Publications - Publikationer

The IGF System and Aging

Conover, C. A., Oxvig, C. — Tue, 01 Apr 2025 17:45:38 +0200

There is strong evidence that IGF signaling is involved in fundamental aspects of the aging process. However, the extracellular part of the IGF system is complex with various receptors, ligand effectors, high-affinity IGF-binding proteins, proteinases, and endogenous inhibitors that all, along with their biological context, must be considered. The IGF system components are evolutionarily conserved, underscoring the importance of understanding this system in physiology and pathophysiology. This review will briefly describe the different components of the IGF system and then discuss past and current literature regarding IGF and aging, with a focus on cellular senescence, model organisms of aging, centenarian genetics, and 3 age-related diseases - pulmonary fibrosis, Alzheimer disease, and macular degeneration - in appropriate murine models and in humans. Commonalities in mechanism suggest conditions where IGF system components may be disease drivers and potential targets in promoting healthy aging in humans.

Studies of the topoisomerase II-mediated cleavage and religation reactions by use of a suicidal double-stranded DNA substrate

Tue, 01 Jan 1991 17:45:38 +0100

The cleavage and religation reactions of eukaryotic topoisomerase II were studied by use of a 5′-recessed DNA substrate containing a strong recognition sequence for the enzyme. Cleavage of the DNA substrate was suicidal, that is the enzyme was unable to religate the cleaved DNA due to a release of DNA 5′ to the cleavage position. With this substrate cleavage products accumulated with time in the absence of protein-denaturing agents, and the cleavage reaction was not reversible with salt. The suicide cleavage complexes contained a kinetically competent topoisomerase II enzyme as determined by the enzyme's ability to perform intermolecular ligation of the cleaved DNA to a free 3′-hydroxyl end on another DNA strand. The efficiency of the religation reaction depended on the ability of the religation substrate to base pair to the DNA in the cleaved enzyme-DNA complex. Higher levels of religation were obtained with dinucleotides than with long DNA substrates. Mononucleotides also were efficiently religated, indicating an ability of the enzyme to mediate religation without making contacts to a long stretch of nucleotides 5′ to the cleavage position.

Drug stimulated DNA cleavage mediated by cauliflower topoisomerase II

Sørensen, B. S., Fukata, H., Jensen, P. S., et al. — Fri, 01 Feb 1991 17:45:38 +0100

We have investigated cauliflower (Brassica oleracea) topoisomerase Il with respect to its interaction with DNA and demonstrate that the enzyme shares the characteristics of topoisomerase II purified from a variety of phylogenetically remote organisms. In the presence of the 2-nitroimidazole Ro 15-0216, cauliflower topoisomerase II-mediated DNA cleavage is extensively stimulated (approximately 20-fold) only at a site recognized as a major cleavage site for the enzyme in the absence of drug. The conservation of the enzyme's DNA specificity in the presence of Ro 15-0216 is in contrast to the effect exerted by traditional topoisomerase II inhibitors, which cause enzyme-mediated cleavage to take place at a multiple number of DNA sites. Ro 15-0216 may therefore prove useful as a tool in the elucidation of the enzyme's DNA interaction sites and its involvement in nucleic acid metabolism in plant cells.

Role of electrostatics in cold adaptation

Thu, 10 Apr 2025 17:45:38 +0200

Psychrophilic (cold-active) organisms have developed enzymes that facilitate sufficient metabolic activity at low temperatures to sustain life. This occurs through molecular adaptations that tend to increase protein flexibility at the expense of stability. However, psychrophiles also vary in their growth conditions. Eurypsychrophiles thrive over a wide temperature range and often prefer temperatures above 20 °C, while stenopsychrophiles grow optimally below 15 °C and are more narrowly adapted to cold temperatures. To elucidate differences between these two classes of enzymes, we here compare the stability and unfolding kinetics of two orthologues of the basal household enzyme triose phosphate isomerase, one from the stenopsychrophilic Antarctic permafrost bacterium Rhodonellum psychrophilum (sTPI) and the other from the eurypsychrophilic Greenland ikaite column bacterium Rhodococcus sp. JG-3 (eTPI). Remarkably, sTPI proved significantly more thermostable and resistant to chemical denaturation than its eurypsychrophilic counterpart, eTPI, in the absence of ionic components in solution, whereas inclusion of electrostatic screening agents in the form of sodium chloride or the charged denaturant guanidinium chloride largely cancelled out this difference. Thus, electrostatics play a prominent role in stabilizing the stenopsychrophilic sTPI, and a mandatory low-temperature growth environment does not preclude the development of considerable thermotolerance for individual enzymes. We were able to increase the thermostability of sTPI using an evolutionary machine learning model, which transferred several sTPI residues into the eTPI active site. While the stabilizing effect was modest, the combination of individual mutations was additive, underscoring the potential of combining multiple beneficial mutations to achieve enhanced enzyme properties.

Gfa1 (glutamine fructose-6-phosphate aminotransferase) is essential for Aspergillus fumigatus growth and virulence

Qin, Q., Wei, P., Usman, S., et al. — Mon, 01 Dec 2025 17:45:38 +0100

Background: Aspergillus fumigatus, the primary etiological agent of invasive aspergillosis, causes over 1.8 million deaths annually. Targeting cell wall biosynthetic pathways offers a promising antifungal strategy. Gfa1, a rate-limiting enzyme in UDP-GlcNAc synthesis, plays a pivotal role in the hexosamine biosynthetic pathway (HBP). Results: Deletion of gfa1 (Δgfa1) results in auxotrophy for glucosamine (GlcN) or N-acetylglucosamine (GlcNAc). Under full recovery (FR) conditions, where minimal medium is supplemented with 5 mM GlcN as the sole carbon source, the Δgfa1 mutant shows growth comparable to the wild-type (WT). However, when supplemented with 5 mM GlcN and 55 mM glucose, growth is partially repressed, likely due to carbon catabolite repression, a condition termed partial repression (PR). Under PR conditions, Δgfa1 exhibits compromised growth, reduced conidiation, defective germination, impaired cell wall integrity, and increased sensitivity to endoplasmic reticulum (ER) stress and high temperatures. Additionally, Δgfa1 demonstrates disruptions in protein homeostasis and iron metabolism. Transcriptomic analysis of the mutant under PR conditions reveals significant alterations in carbohydrate and amino acid metabolism, unfolded protein response (UPR) processes, and iron assimilation. Importantly, Gfa1 is essential for A. fumigatus virulence, as demonstrated in Caenorhabditis elegans and Galleria mellonella infection models. Conclusions: These findings underscore the critical role of Gfa1 in fungal pathogenicity and suggest its potential as a therapeutic target for combating A. fumigatus infections.

3D dental similarity quantification in forensic odontology identification

Kofod Petersen, A., Forgie, . A. H., Villesen, P., Staun Larsen, L. — Thu, 01 May 2025 17:45:38 +0200

Structure of the [Ca]E2P intermediate of Ca²⁺-ATPase 1 from Listeria monocytogenes

Basse Hansen, S., Flygaard, R. K., Kjaergaard, M., Nissen, P. — Wed, 01 Jan 2025 17:45:38 +0100

Active transport by P-type Ca²⁺-ATPases maintain internal calcium stores and a low cytosolic calcium concentration. Structural studies of mammalian sarco/endoplasmic reticulum Ca²⁺-ATPases (SERCA) have revealed several steps of the transport cycle, but a calcium-releasing intermediate has remained elusive. Single-molecule FRET studies of the bacterial Ca²⁺-ATPase LMCA1 revealed an intermediate of the transition between so-called [Ca]E1P and E2P states and suggested that calcium release from this intermediate was the essentially irreversible step of transport. Here, we present a 3.5 Å resolution cryo-EM structure for a four-glycine insertion mutant of LMCA1 in a lipid nanodisc obtained under conditions with calcium and ATP and adopting such an intermediate state, denoted [Ca]E2P. The cytosolic domains are positioned in the E2P-like conformation, while the calcium-binding transmembrane (TM) domain adopts a calcium-bound E1P-ADP-like conformation. Missing density for the E292 residue at the calcium site (the equivalent of SERCA1a E309) suggests flexibility and a site poised for calcium release and proton uptake. The structure suggests a mechanism where ADP release and re-organization of the cytoplasmic domains precede calcium release.

High-dose vitamin D supplementation in pregnancy ameliorates obesity-induced increase in maternal IL-1β level without affecting obesity-induced increase in IL-6 and MCP-1

Wed, 01 Jan 2025 17:45:38 +0100

Background Maternal and placental inflammatory activity is carefully regulated during pregnancy and changes in inflammatory status are associated with pregnancy complications and health deficits in the offspring including adverse effects on neurodevelopment. Overweight/obesity is associated with chronic inflammation, thereby contributing to adverse effects. Disturbingly, overweight and obesity are highly prevalent among pregnant women worldwide. Vitamin D (vitD) possess immunomodulatory effects and is believed to support healthy pregnancy. Endocrinological societies recommend empiric vitD supplementation in pregnancy but there is no consensus on the minimal supplementation dose Methods An adjacent study to GRAVIT-D (no. NCT04291313, ClinicalTrial.gov), a double-blinded randomized trial investigating the clinical benefits of increasing vitD supplementation in pregnancy from 400IU to 3600IU/day from gestational week 11–16 onwards. In a subgroup, (n = 156), multiplex ELISA targeting third-semester serum levels of IL-1β, IL-6, IL-10, TNFα, MCP-1, and IL-17A was performed. Inflammation signals were correlated with the vitD dose given, subsequently analysing the effect of vitD in relation to the pre-pregnancy body mass index (BMI) within each treatment arm comparing the inflammatory response in WHO-defined BMI groups,  30 kg/m2. Main Results High pre-pregnancy BMI was associated with increased IL6 and MCP1 in both the 400IU and the 3600 IU exposed group. IL1β levels increased with BMI if using a 400IU/day supplement. High dose vitD supplementation ameliorated BMI effects on IL1β. Conclusion and Perspectives Increased vitD supplementation during pregnancy may ameliorate some overweight/obesity-induced inflammatory activity. Further studies are needed to determine the vitD need in pregnancies complicated by obesity and overweight.

Cold-Active Starch-Degrading Enzymes from a Cold and Alkaline Greenland Environment: Role of Ca 2+ Ions and Conformational Dynamics in Psychrophilicity.

Bendtsen, M. K., Nowak, J. S., Paiva, P., et al. — Fri, 14 Mar 2025 17:45:38 +0100

Cold-active enzymes hold promise for energy-efficient processes. Amylases are widely used in household and industrial applications, but only a few are cold-active. Here we describe three novel secreted amylases, Rho13, Ika2 and I3C6, all from bacteria growing in the cold and alkaline ikaite columns in Greenland. They all hydrolyzed starch to smaller malto-oligomers, but only Rho13 and Ika2 hydrolyzed cyclodextrins, and only Ika2 displayed transglycosylation activity. Ika2 forms a stable dimer, while both Rho13 and I3C6 are mainly monomeric. They all have optimal active temperatures around 30-35 °C and significant enzymatic activity below 20 °C, but Rho13 and I3C6 had an alkaline optimal pH, while Ika2 was markedly acidophilic. They showed complex dependence on Ca 2+ concentration, with the activity of Rho13 and I3C6 following a bell-shaped curve and Ika2 being unaffected; however, removal of Ca 2+ reduced the stability of all three enzymes. Loss of structure occurred well above the temperature of optimal activity, showing the characteristic psychrophilic divorce between activity and stability. MD simulations showed that Ika2 did not have a well-defined Ca 2+ binding site, while Rho13 and I3C6 both maintained one stably bound Ca 2+ ion. We identified psychrophilic features as higher levels of backbone fluctuations compared to mesophilic counterparts, based on a lower number of internal hydrogen bonds and salt bridges. This increased fluctuation was also found in regions outside the active site and may provide easier substrate access and accommodation, as well as faster barrier transitions. Our work sheds further light on the many ways in which psychrophilic enzymes adapt to increased catalysis at lower temperatures.

Distribution, activity, and storage of xanthine oxidase in bovine milk fractions

Gadegaard, I. S. E., Madsen, C. M., Johansen, P. M., Rasmussen, J. T. — Wed, 01 Jan 2025 17:45:38 +0100

Mammal enzyme xanthine dehydrogenase/oxidase exists in two interconvertible forms, with oxidase dominating in milk. Initially, the enzyme was affiliated to the milk fat globule membrane, but it is more widely distributed. Xanthine dehydrogenase/oxidase is involved in purine catabolism, but accumulated evidence reveals a much more complex and versatile role in milk, prompting the need for more accurate knowledge about its fractional presence. The content and activity of xanthine oxidase were estimated in a wide range of bovine milk fractions, with 220 mg L⁻¹ and 3.93 U g⁻¹ protein in whole milk, respectively. Besides buttermilk and fat globule membrane, high amounts of xanthine oxidase activity were found in extracellular vesicles and whey. Inclusion of detergent was shown to be important for release of all embedded xanthine oxidase activity. Finally, the conducted experiments disclosed effects of different storage conditions on the enzymatic integrity, showing that storage at −20 °C is not recommendable.

CRISPR/Cas9-mediated knockout of DYRK1B in triple-negative breast cancer cells

Rashidi, A., Füchtbauer, E. M., Vahabzadeh, Z., et al. — Wed, 01 Jan 2025 17:45:38 +0100

Breast cancer is the most common cancer among women worldwide, with the triple-negative subtype (TNBC) having a poor prognosis and limited treatment options. DYRK1B is a dual-specificity kinase that regulates the cell cycle and quiescence. While its role in several cancers has been characterized, its role in TNBC remains unknown. In this study, we used CRISPR/Cas9 to delete DYRK1B in MDA-MB-231 cells, a model of TNBC and investigated its effects on cell proliferation, apoptosis, invasion, migration, angiogenesis, and response to Paclitaxel. The DYRK1B knockout (KO) was confirmed by PCR, Real-time qPCR, and Sanger sequencing. KO cells showed a significant reduction in cell proliferation, colony formation, invasion, and migration. Additionally, there were alterations in mRNA expression levels of several genes related to the cell cycle, angiogenesis, and cell motility, such as CCND1, MCM2, PCNA, CDKN1B, HIF1A, VEGFA, and WASF3, compared to MDA-MB-231 wild type (WT) cells. Immunocytochemistry results assessing Ki67 expression, a marker of cell proliferation, indicated that DYRK1B knockout cells had significantly lower Ki67 expression than WT cells. Furthermore, KO cells exhibited increased apoptosis and sensitivity to contact inhibition. Additionally, the IC₅₀ for Paclitaxel was significantly decreased in KO cells. These results suggest that DYRK1B plays an important role in the survival and invasion of TNBC cells and might be a potential candidate as a new therapeutic target for this disease.

Comprehensive genomic characterization of early-stage bladder cancer

Prip, F., Lamy, P., Lindskrog, S. V., et al. — Wed, 01 Jan 2025 17:45:38 +0100

Understanding the molecular landscape of nonmuscle-invasive bladder cancer (NMIBC) is essential to improve risk assessment and treatment regimens. We performed a comprehensive genomic analysis of patients with NMIBC using whole-exome sequencing (n = 438), shallow whole-genome sequencing (n = 362) and total RNA sequencing (n = 414). A large genomic variation within NMIBC was observed and correlated with different molecular subtypes. Frequent loss of heterozygosity in FGFR3 and 17p (affecting TP53) was found in tumors with mutations in FGFR3 and TP53, respectively. Whole-genome doubling (WGD) was observed in 15% of the tumors and was associated with worse outcomes. Tumors with WGD were genomically unstable, with alterations in cell-cycle-related genes and an altered immune composition. Finally, integrative clustering of multi-omics data highlighted the important role of genomic instability and immune cell exhaustion in disease aggressiveness. These findings advance our understanding of genomic differences associated with disease aggressiveness in NMIBC and may ultimately improve patient stratification.

Genetic predictions of eye and hair colour in the Danish population

Cabrejas-Olalla, A., Jørgensen, F. G., Cheng, J. Y., et al. — Sun, 01 Jun 2025 17:45:38 +0200

Genetic predictions of eye and hair colour are prominent examples of forensic DNA phenotyping that can help resolve criminal cases. The advent of high-throughput genotyping technologies in forensic genetics opens up the possibility of applying polygenic risk scores in forensic settings. In this work, we compare the performance of HIrisPlex with PRSice-2 in predicting eye and hair colour to gain insights into the relative benefits of new approaches. Predictions were carried out on 584 Danish high school students for which genetic and self-reported phenotype data were available. Prediction of brown eye colour was very accurate (AUC = 0.98), followed by blue eye colour (AUC = 0.82), while it failed for intermediate eye colour (AUC = 0.57). As for hair colour, red and black were overall better predicted than blond and brown, and PRSice-2 performed better in all but the black hair colour. Despite the limitations of the study, HIrisPlex exhibited its usual high performance in the prediction of brown and blue eye colour, as well as red and black hair colour. However, PRSice-2 offered overall improvements in hair colour prediction over HIrisPlex suggesting that there is room for improvement in forensic DNA phenotyping by using polygenic risk scores.

Diagnosis and Staging of Metabolic Dysfunction-Associated Steatotic Liver Disease Using Biomarker-Directed Aptamer Panels

Kjær, M. B., Jørgensen, A. G., Fjelstrup, S., et al. — Sat, 01 Feb 2025 17:45:38 +0100

Metabolic dysfunction-associated steatotic liver disease (MASLD) affects one-third of adults globally. Despite efforts to develop non-invasive diagnostic tools, liver biopsy remains the gold standard for diagnosing metabolic dysfunction-associated steatohepatitis (MASH) and assessing fibrosis. This study investigated RNA aptamer panels, selected using APTASHAPE technology, for non-invasive MASLD diagnosis and fibrosis stratification. Aptamer panels were selected in a cohort of individuals with MASLD (development cohort, n = 77) and tested in separate cohorts: one with MASLD (test cohort, n = 57) and one assessed for bariatric surgery (bariatric cohort, n = 62). A panel distinguishing MASLD without steatohepatitis from MASH accurately stratified individuals in the development cohort (AUC = 0.83) but failed in the test and bariatric cohorts. It did, however, distinguish healthy controls from individuals with MASLD, achieving an AUC of 0.72 in the test cohort. A panel for fibrosis stratification differentiated F0 from F3–4 fibrosis in the development cohort (AUC = 0.68) but not in other cohorts. Mass spectrometry identified five plasma proteins as potential targets of the discriminative aptamers, with complement factor H suggested as a novel MASLD biomarker. In conclusion, APTASHAPE shows promise as a non-invasive tool for diagnosing and staging MASLD and identifying associated plasma biomarkers.

Stem cells in ageing and longevity: a new section in Biogerontology

Fraifeld, V., Rattan, S. — Tue, 01 Apr 2025 17:45:38 +0200

The genomic consequences and persistence of sociality in spiders

Sat, 01 Mar 2025 17:45:38 +0100

In cooperatively breeding social animals, a few individuals account for all reproduction. In some taxa, sociality is accompanied by a transition from outcrossing to inbreeding. In concert, these traits reduce effective population size, potentially rendering transitions to sociality “evolutionarily dead-ends.” We addressed this hypothesis in a comparative genomic study in spiders, in which sociality has evolved independently at least 23 times, but social branches are recent and short. We present genomic evidence for the evolutionary dead-end hypothesis in a spider genus with three independent transitions to sociality. We assembled and annotated high-quality, chromosome-level reference genomes from three pairs of closely related social and subsocial Stegodyphus species. We timed the divergence between the social and subsocial species pairs to be from 1.3 million to 1.8 million years. Social evolution in spiders involves a shift from outcrossing to inbreeding and from an equal to a female-biased sex ratio, causing severe reductions in effective population size and decreased efficacy of selection. We show that transitions to sociality only had full effect on purifying selection at 119, 260, and 279 kya, respectively, and follow similar convergent trajectories of progressive loss of diversity and shifts to an increasingly female-biased sex ratio. This almost deterministic genomic response to sociality may explain why social spider lineages do not persist. What causes species extinction is not clear, but either could be selfish meiotic drive eliminating the production of males or could be an inability to retain genome integrity in the face of extremely reduced efficacy of selection.

A roadmap toward the synthesis of life

Kriebisch, C. M.E., Bantysh, O., Baranda Pellejero, L., et al. — Thu, 13 Mar 2025 17:45:38 +0100

The synthesis of life from non-living matter has captivated and divided scientists for centuries. This bold goal aims at unraveling the fundamental principles of life and leveraging its unique features, such as its resilience, sustainability, and ability to evolve. Synthetic life represents more than an academic milestone—it has the potential to revolutionize biotechnology, medicine, and materials science. Although the fields of synthetic biology, systems chemistry, and biophysics have made great strides toward synthetic life, progress has been hindered by social, philosophical, and technical challenges, such as vague goals, misaligned interdisciplinary efforts, and incompletely addressing public and ethical concerns. Our perspective offers a roadmap toward the synthesis of life based on discussions during a 2-week workshop with scientists from around the globe.

Integrative in silico and biochemical analyses demonstrate direct Arl3-mediated ODA16 release from the intraflagellar transport machinery

Wang, J., Kidmose, R. T., Boegholm, N., et al. — Sat, 01 Mar 2025 17:45:38 +0100

Outer dynein arms (ODAs) are essential for ciliary motility and are preassembled in the cytoplasm before trafficking into cilia by intraflagellar transport (IFT). ODA16 is a key adaptor protein that links ODAs to the IFT machinery via direct interaction with the IFT46 protein. However, the molecular mechanisms regulating the assembly, transport, and release of ODAs remain poorly understood. Here, we employ AlphaPulldown, an in silico screening method, to identify direct interactors of ODA16, including the dynein adaptor IDA3 and the small GTPase Arl3. We use structural modeling, biochemical, and biophysical assays on Chlamydomonas and human proteins to elucidate the interactions and regulatory mechanisms governing the IFT of ODAs. We identify a conserved N-terminal motif in Chlamydomonas IFT46 that mediates its binding to one side of the ODA16 structure. Biochemical dissection reveals that IDA3 and Arl3 bind to the same surface of ODA16 (the C-terminal β-propeller face), which is opposite to the IFT46 binding site, enabling them to dissociate ODA16 from IFT46, likely through an allosteric mechanism. Our findings provide mechanistic insights into the concerted actions of IFT and adaptor proteins in ODA transport and regulation.

The Composition of the Fecal and Mucosa-adherent Microbiota Varies Based on Age and Disease Activity in Ulcerative Colitis

Malham, M., Vestergaard, M. V., Bataillon, T., et al. — Sat, 01 Feb 2025 17:45:38 +0100

Background: Pediatric-onset ulcerative colitis (pUC) represents a more aggressive disease phenotype compared with adult-onset UC. We hypothesized that this difference can, in part, be explained by the composition of the microbiota. Methods: In a prospective, longitudinal study, we included pediatric (N=30) and adult (N=30) patients with newly or previously (>1 year) diagnosed UC. We analyzed the microbiota composition in the mucosa-adherent microbiota at baseline, using 16S rRNA gene sequencing, and the fecal microbiota at baseline and at 3-month intervals, using shotgun metagenomics. Results: For fecal samples, the bacterial composition differed between pUC and aUC in newly diagnosed patients (β-diversity, Bray Curtis: R²=0.08, P=.02). In colon biopsies, microbial diversity was higher in aUC compared with pUC (α-diversity, Shannon: estimated difference 0.54, P=.006). In the mucosa-adherent microbiota, Alistipes finegoldii was negatively associated with disease activity in pUC while being positively associated in aUC (estimate: -0.255 and 0.098, P=.003 and P=.02 in pUC and aUC, respectively). Finally, we showed reduced stability of the fecal microbiota in pediatric patients, evidenced by a different composition of the fecal microbiota in newly and previously diagnosed pUC, a pattern not found in adults. Conclusions: Our results indicate that pediatric UC patients have a more unstable fecal microbiota and a lower α diversity than adult patients and that the microbiota composition differs between aUC and pUC patients. These findings offer some explanation for the observed differences between pUC and aUC and indicate that individualized approaches are needed if microbiota modifications are to be used in the future treatment of UC.

Polygenic scores for autism are associated with reduced neurite density in adults and children from the general population

Gu, Y., Maria-Stauffer, E., Bedford, S. A., et al. — Mon, 24 Feb 2025 17:45:38 +0100

Genetic variants linked to autism are thought to change cognition and behaviour by altering the structure and function of the brain. Although a substantial body of literature has identified structural brain differences in autism, it is unknown whether autism-associated common genetic variants are linked to changes in cortical macro- and micro-structure. We investigated this using neuroimaging and genetic data from adults (UK Biobank, N = 31,748) and children (ABCD, N = 4928). Using polygenic scores and genetic correlations we observe a robust negative association between common variants for autism and a magnetic resonance imaging derived phenotype for neurite density (intracellular volume fraction) in the general population. This result is consistent across both children and adults, in both the cortex and in white matter tracts, and confirmed using polygenic scores and genetic correlations. There were no sex differences in this association. Mendelian randomisation analyses provide no evidence for a causal relationship between autism and intracellular volume fraction, although this should be revisited using better powered instruments. Overall, this study provides evidence for shared common variant genetics between autism and cortical neurite density.

Prepubertal Children With Obesity Have High Free IGF-1 Levels and Accelerated Growth Despite Reduced Pappalysin Levels

Martín-Rivada, Á., Martos-Moreno, G., Guerra-Cantera, S., et al. — Sat, 01 Mar 2025 17:45:38 +0100

Background: Prepubertal children with obesity frequently have enhanced growth, accelerated skeletal maturation, and changes in the growth hormone-insulin-like growth factor (GH-IGF) axis. However, the involvement of pappalysins (PAPP-A, PAPP-A2) and stanniocalcins (STC1, STC2) as regulators of IGF bioavailability has not been studied in obesity. Objective: We aimed to determine the effects of childhood obesity and weight reduction on serum levels of PAPP-A, PAPP-A2, STC1, and STC2 and their relationship with IGF bioavailability, growth, and other components of the GH-IGF system. Methods: Prepubertal children with severe obesity (150, 50% males/females, age: 7.72 ± 2.05 years, BMI z-score: 4.95 ± 1.70, height z-score: 1.28 ± 1.04) were studied at diagnosis and after a minimum of 0.5 BMI z-score reduction. Two hundred and six healthy age- and sex-matched children were used as controls. Results: Children with obesity had decreased serum concentrations of PAPP-A, PAPP-A2 and STC2, but increased total and free IGF-I, intact IGFBP-3, acid-labile subunit (ALS), IGF-II, and insulin levels, with no difference in the free IGF-I/total IGF-I ratio. Neither the standardized body mass index (BMI) nor height correlated with any biochemical parameter analyzed. A decrease in IGF-II, insulin, and ALS with an increase in IGFBP-2 and -5, STC2, and PAPP-A were observed after weight loss. Conclusion: Increased circulating total and free IGF-I, insulin, and IGF-II may all contribute to the increased rate of prepubertal growth and bone maturation observed in children with obesity, with STC2 possibly being involved.

Shared genetics of ADHD, cannabis use disorder and cannabis use and prediction of cannabis use disorder in ADHD

Nielsen, T. T., Duan, J., Levey, D. F., et al. — Sun, 01 Sep 2024 17:45:38 +0200

Cannabis use disorder (CUD) and cannabis use (CU) are prevalent conditions co-occurring with attention-deficit hyperactivity disorder (ADHD). Here we report results from a cross-disorder genome-wide association study of ADHD and CUD or CU. We identified 36 concordant genome-wide significant loci for ADHD–CUD and ten loci for ADHD–CU. DRD2 was identified as an ADHD–CUD risk gene. ADHD–CUD risk genes showed high expression across brain tissues and brain developmental stages, which was not observed for ADHD–CU genes. ADHD–CUD and ADHD–CU showed similar genetic correlations with substance use, whereas they differed for substance-use disorders. Individuals with ADHD–CUD had increased polygenic scores (PGS) for psychiatric disorders compared with those with ADHD without CUD and increased burden of rare deleterious variants. Stratification of individuals with ADHD by their CUD PGS revealed an absolute risk of 22% for comorbid CUD in the highest CUD-PGS bin—much higher than 1.6% risk among controls. Sex-specific differences were substantial with an approximately 10% higher CUD risk among men in the highest CUD-PGS bin.

Investigating strategies for creating cross-linked amyloid fibril networks through branching of amyloid growth

Olsen, W. P., Larsen, A. K., Christensen, J. L., Malle, M. G., Otzen, D. E. — Fri, 07 Mar 2025 17:45:38 +0100

Hydrogel biomaterials have been extensively explored for applications in medicine, materials science, and the development of functionalized materials. Traditionally, hydrogels were produced using simple polymers, but advancements over recent decades have enabled the use of biological materials such as proteins, peptides, polysaccharides, and even amyloid fibrils. Among these, amyloid-based hydrogels have demonstrated unique advantages, including enhanced cell adhesion and differentiation. Furthermore, they can be engineered as living materials using bacteria capable of producing and repairing the hydrogel in situ. Here we investigate novel strategies for controlling amyloid fibrillation using the functional amyloid CsgA. We designed fusion proteins combining two CsgA moieties to explore methods for creating branched fibril networks. Our approach utilized two distinct strategies: passive and active branching. The passive strategy involved direct fusion of two CsgA moieties separated by a designed alpha-helical linker and engineered to integrate into fibrils without external intervention. The active branching approach incorporated a redox-sensitive CsgA variant containing an internal disulfide bridge that blocks fibrillation until reduced. This design allows for precise control of amyloid fibrillation in the active variants. We analyzed these constructs qualitatively approach using a combination of transmission electron microscopy (TEM), real-time atomic force microscopy (AFM), and total internal reflection fluorescence (TIRF) microscopy, supported by quantitative image analysis. While we did not observe direct evidence of fibril branching, our modifications led to significant changes in fibrillation behavior. Notably, TIRF imaging revealed a marked increase in high-density fibril regions following the activation of our engineered constructs, indicating the potential for controlled assembly of higher-order structures. These findings provide new insights into controlling amyloid fibrillation and suggest alternative strategies for manipulating fibril organization. The observed ability to alter local fibril density through chemical triggers offers promising directions for developing responsive biomaterials. We propose refinements for future design and suggest new directions to optimize amyloid-based hydrogels for next-generation biomaterial applications.

Estimating Gene Conversion Tract Length and Rate From PacBio HiFi Data

Charmouh, A. P., Porsborg, P. S., Hansen, L. T., et al. — Sat, 01 Feb 2025 17:45:38 +0100

Gene conversions are broadly defined as the transfer of genetic material from a "donor" to an "acceptor" sequence and can happen both in meiosis and mitosis. They are a subset of noncrossover (NCO) events and, like crossover (CO) events, gene conversion can generate new combinations of alleles and counteract mutation load by reverting germline mutations through GC-biased gene conversion. Estimating gene conversion rate and the distribution of gene conversion tract lengths remains challenging. We present a new method for estimating tract length, rate, and detection probability of NCO events directly in HiFi PacBio long read data. The method can be used to make inference from sequencing of gametes from a single individual. The method is unbiased even under low single nucleotide variant (SNV) densities and does not necessitate any demographic or evolutionary assumptions. We test the accuracy and robustness of our method using simulated datasets where we vary length of tracts, number of tracts, the genomic SNV density, and levels of correlation between SNV density and NCO event position. Our simulations show that under low SNV densities, like those found in humans, only a minute fraction (∼2%) of NCO events are expected to become visible as gene conversions by moving at least 1 SNV. We finally illustrate our method by applying it to PacBio sequencing data from human sperm.

The Medicago truncatula LYR4 intracellular domain serves as a scaffold in immunity signaling independent of its phosphorylation activity

Simonsen, B., Rübsam, H., Kolte, M. V., et al. — Mon, 10 Mar 2025 17:45:38 +0100

The therapeutic potential of circular RNAs

O’Leary, E., Jiang, Y., Kristensen, L. S., Hansen, T. B., Kjems, J. — Tue, 01 Apr 2025 17:45:38 +0200

Over the past decade, research into circular RNA (circRNA) has increased rapidly, and over the past few years, circRNA has emerged as a promising therapeutic platform. The regulatory functions of circRNAs, including their roles in templating protein translation and regulating protein and RNA functions, as well as their unique characteristics, such as increased stability and a favourable immunological profile compared with mRNAs, make them attractive candidates for RNA-based therapies. Here, we describe the properties of circRNAs, their therapeutic potential and technologies for their synthesis. We also discuss the prospects and challenges to be overcome to unlock the full potential of circRNAs as drugs.

Comparison of cable bacteria genera reveals details of their conduction machinery

Digel, L., Justesen, M. L., Madsen, N. S., et al. — Mon, 17 Feb 2025 17:45:38 +0100

Cable bacteria are centimeter-long multicellular bacteria conducting electricity through periplasmic conductive fibers (PCFs). Using single-strain enrichments of the genera Electrothrix and Electronema we systematically investigate variations and similarities in morphology and electrical properties across both genera. Electrical conductivity of different PCFs spans three orders of magnitude warranting further investigations of the plasticity of their conduction machinery. Using electron microscopy and elemental analyses, we show that the two cable bacteria genera have similar cell envelopes and cell–cell junction ultrastructures. Iron, sulfur, and nickel signals are co-localized with the PCFs, indicating key functional roles of these elements. The PCFs are organized as stranded rope-like structures composed of multiple strands. Furthermore, we report lamellae-like structures formed at the cell–cell junctions with a core layer connecting to the PCFs, and intriguing vesicle-like inner membrane invaginations below the PCFs. Finally, using bioinformatic tools, we identify a cytochrome family with predicted structural homology to known multi-heme nanowire proteins from other electroactive microorganisms and suggest that these cytochromes can play a role in the extra- or intercellular electron conduction of cable bacteria.

Interactions between pathological and functional amyloid

Otzen, D. E., Peña-Díaz, S., Widmann, J., et al. — Sat, 01 Mar 2025 17:45:38 +0100

The amyloid state of proteins occurs in many different contexts in Nature and in modern society, ranging from the pathological kind (neurodegenerative diseases and amyloidosis) via man-made forms (food processing and - to a much smaller extent - protein biologics) to functional versions (bacterial biofilm, peptide hormones and signal transmission). These classes all come together in the human body which endogenously produces amyloidogenic protein able to form pathological human amyloid (PaHA), hosts a microbiome which continuously makes functional bacterial amyloid (FuBA) and ingests food which can contain amyloid. This can have grave consequences, given that PaHA can spread throughout the body in a "hand-me-down" fashion from cell to cell through small amyloid fragments, which can kick-start growth of new amyloid wherever they encounter monomeric amyloid precursors. Amyloid proteins can also self- and cross-seed across dissimilar peptide sequences. While it is very unlikely that ingested amyloid plays a role in this crosstalk, FuBA-PaHA interactions are increasingly implicated in vivo amyloid propagation. We are now in a position to understand the structural and bioinformatic basis for this cross-talk, thanks to the very recently obtained atomic-level structures of the two major FuBAs CsgA (E. coli) and FapC (Pseudomonas). While there are many reports of homology-driven heterotypic interactions between different PaHA, the human proteome does not harbor significant homology to CsgA and FapC. Yet we and others have uncovered significant cross-stimulation (and in some cases inhibition) of FuBA and PaHA both in vitro and in vivo, which we here rationalize based on structure and sequence. These interactions have important consequences for the transmission and development of neurodegenerative diseases, not least because FuBA and PaHA can come into contact via the gut-brain interface, recurrent infections with microbes and potentially even through invasive biofilm in the brain. Whether FuBA and PaHA first interact in the gut or the brain, they can both stimulate and block each other's aggregation as well as trigger inflammatory responses. The microbiome may also affect amyloidogenesis in other ways, e.g. through their own chaperones which recognize and block growth of both PaHA and FuBA as we show both experimentally and computationally. Heterotypic interactions between and within PaHA and FuBA both in vitro and in vivo are a vital part of the amyloid phenomenon and constitute a vibrant and exciting frontier for future research.

Endothelial and neuronal engagement by AAV-BR1 gene therapy alleviates neurological symptoms and lipid deposition in a mouse model of Niemann-Pick type C2

Rasmussen, C. L. M., Frederiksen, S. F., Heegaard, C. W., et al. — Mon, 01 Dec 2025 17:45:38 +0100

Background: Patients with the genetic disorder Niemann-Pick type C2 disease (NP-C2) suffer from lysosomal accumulation of cholesterol causing both systemic and severe neurological symptoms. In a murine NP-C2 model, otherwise successful intravenous Niemann-Pick C2 protein (NPC2) replacement therapy fails to alleviate progressive neurodegeneration as infused NPC2 cannot cross the blood–brain barrier (BBB). Genetic modification of brain endothelial cells (BECs) is thought to enable secretion of recombinant proteins thereby overcoming the restrictions of the BBB. We hypothesized that an adeno-associated virus (AAV-BR1) encoding the Npc2 gene could cure neurological symptoms in Npc2−/− mice through transduction of BECs, and possibly neurons via viral passage across the BBB. Methods: Six weeks old Npc2−/− mice were intravenously injected with the AAV-BR1-NPC2 vector. Composite phenotype scores and behavioral tests were assessed for the following 6 weeks and visually documented. Post-mortem analyses included gene expression analyses, verification of neurodegeneration in Purkinje cells, determination of NPC2 transduction in the CNS, assessment of gliosis, quantification of gangliosides, and co-detection of cholesterol with NPC2 in degenerating neurons. Results: Treatment with the AAV-BR1-NPC2 vector improved motor functions, reduced neocortical inflammation, and preserved Purkinje cells in most of the mice, referred to as high responders. The vector exerted tropism for BECs and neurons resulting in a widespread NPC2 distribution in the brain with a concomitant reduction of cholesterol in adjacent neurons, presumably not transduced by the vector. Mass spectrometry imaging revealed distinct lipid alterations in the brains of Npc2−/− mice, with increased GM2 and GM3 ganglioside accumulation in the cerebellum and hippocampus. AAV-BR1-NPC2 treatment partially normalized these ganglioside distributions in high responders, including restoration of lipid profiles towards those of Npc2+/+ controls. Conclusion: The data suggests cross-correcting gene therapy to the brain via delivery of NPC2 from BECs and neurons.

Structural basis of THC analog activity at the Cannabinoid 1 receptor

Thorsen, T. S., Kulkarni, Y., Sykes, D. A., et al. — Mon, 01 Dec 2025 17:45:38 +0100

Tetrahydrocannabinol (THC) is the principal psychoactive compound derived from the cannabis plant Cannabis sativa and approved for emetic conditions, appetite stimulation and sleep apnea relief. THC’s psychoactive actions are mediated primarily by the cannabinoid receptor CB₁. Here, we determine the cryo-EM structure of HU210, a THC analog and widely used tool compound, bound to CB₁ and its primary transducer, G_i1. We leverage this structure for docking and 1000 ns molecular dynamics simulations of THC and 10 structural analogs delineating their spatiotemporal interactions at the molecular level. Furthermore, we pharmacologically profile their recruitment of G_i and β-arrestins and reversibility of binding from an active complex. By combining detailed CB₁ structural information with molecular models and signaling data we uncover the differential spatiotemporal interactions these ligands make to receptors governing potency, efficacy, bias and kinetics. This may help explain the actions of abused substances, advance fundamental receptor activation studies and design better medicines.

Pharmacological blocking of microfibrillar-associated protein 4 reduces retinal neoangiogenesis and vascular leakage

Schlosser, A., Pilecki, B., Allen, C., et al. — Wed, 05 Mar 2025 17:45:38 +0100

Neovascular age-related macular degeneration and diabetic macular edema are leading causes of vision loss evoked by retinal neovascularization and vascular leakage. The glycoprotein microfibrillar-associated protein 4 (MFAP4) is an integrin α_Vβ_3/5/6 ligand present in the extracellular matrix. Single-cell transcriptomics reveal MFAP4 expression in cell types in close proximity to vascular endothelial cells, including choroidal vascular mural cells, retinal astrocytes, and Müller cells. Binding of the anti-MFAP4 antibody, hAS0326, makes MFAP4 inaccessible for integrin receptor interaction, and thereby hAS0326 blocked endothelial cell motility in vitro. Intravitreal hAS0326 inhibited retinal vascular lesion area and neovessel volume in a laser-induced choroidal neovascularization mouse model, vascular permeability in streptozotocin-induced retinopathy, and vascular leakage area in a chronic non-human primate model of DL-2-aminoadipic acid-induced retinopathy. One dose of hAS0326 showed duration of efficacy of at least 12 weeks in the latter model. Moreover, hAS0326 treatment significantly enriched Gene Ontology terms involving reduction of integrin binding. Our data suggest that hAS0326 constitutes a promising treatment of neovascularization and vascular leakage in retinal diseases.

Milk osteopontin mediates zinc uptake in intestinal cells in the presence of phytic acid

Christensen, B., Krüger, T. F., Hjorth, T. P., Buhl, E. H., Sørensen, E. S. — Sat, 01 Feb 2025 17:45:38 +0100

The bioavailability and the intestinal absorption of the essential mineral zinc are challenged by the food matrix and especially the content of zinc chelating antinutrients. Many milk proteins and peptides affect zinc bioavailability. Osteopontin (OPN) is an acidic and highly phosphorylated whey protein that has been shown to bind calcium, magnesium and iron. Here we report the zinc binding properties of OPN, and the effect of OPN-Zn complexes on zinc absorption in Caco-2 cells. By isothermal titration calorimetry milk OPN was shown to bind approximately 36 zinc ions (K_D of ∼70 μM). The binding was mainly mediated by the phosphorylations in the protein. OPN retained zinc bound after in vitro simulated gastrointestinal transit. Interestingly the OPN-Zn complex enhanced zinc bioavailability in the presence of phytic acid, compared to inorganic zinc salts. Zinc uptake mediated by OPN significantly upregulated the gene expression of MT1G and ZnT1 which are crucial proteins involved in preserving enterocyte zinc homoeostasis. These results indicate that OPN could be incorporated into functional foods and infant formulas to increase zinc bioavailability and uptake.

Heterotypic interactions among members of the death domain superfamily with implications for p75^NTR-mediated co-signaling

Li, Z., Xue, Y., Duan, Y., et al. — Tue, 01 Apr 2025 17:45:38 +0200

The death domain (DD) superfamily, a group of protein interaction modules, plays a crucial role in regulating downstream signaling pathways through the formation of specific complexes. However, the aggregation-prone behavior of many DD superfamily members in solution limits their interaction studies, and the structural mechanisms underlying oligomeric assembly involving different DD subfamilies are not fully understood. Here, we demonstrate that RIP2-CARD retains its native folding and protein function for interacting with the DD of p75 neurotrophin receptor (p75^NTR) in pure water rather than under acidic conditions of pH 5.0 or lower. Leveraging this pure water system, we uncover the heterotypic interactions among p75^NTR-DD, RIP2-CARD, and TRADD-DD, elucidate their ternary HADDOCK complex structure, and identify a new specific binding interface between RIP2-CARD and TRADD-DD. Using developing cortical neurons with endogenous p75^NTR, we demonstrated that co-signaling of the p75^NTR:TRADD:RIP2 tricomplex may shift the signaling balance towards survival by reducing the efficiency of death pathways. Our findings suggest a mechanism in which p75^NTR serves as a molecular scaffold, assembling diverse signaling components to co-activate multiple signaling cascades at the receptor level.

The Digital Health Competencies in Medical Education Framework

Car, J., Ong, Q. C., Erlikh Fox, T., et al. — Thu, 02 Jan 2025 17:45:38 +0100

Importance: Rapid digitalization of health care and a dearth of digital health education for medical students and junior physicians worldwide means there is an imperative for more training in this dynamic and evolving field. Objective: To develop an evidence-informed, consensus-guided, adaptable digital health competencies framework for the design and development of digital health curricula in medical institutions globally. Evidence Review: A core group was assembled to oversee the development of the Digital Health Competencies in Medical Education (DECODE) framework. First, an initial list was created based on findings from a scoping review and expert consultations. A multidisciplinary and geographically diverse panel of 211 experts from 79 countries and territories was convened for a 2-round, modified Delphi survey conducted between December 2022 and July 2023, with an a priori consensus level of 70%. The framework structure, wordings, and learning outcomes with marginal percentage of agreement were discussed and determined in a consensus meeting organized on September 8, 2023, and subsequent postmeeting qualitative feedback. In total, 211 experts participated in round 1, 149 participated in round 2, 12 participated in the consensus meeting, and 58 participated in postmeeting feedback. Findings: The DECODE framework uses 3 main terminologies: domain, competency, and learning outcome. Competencies were grouped into 4 domains: professionalism in digital health, patient and population digital health, health information systems, and health data science. Each competency is accompanied by a set of learning outcomes that are either mandatory or discretionary. The final framework comprises 4 domains, 19 competencies, and 33 mandatory and 145 discretionary learning outcomes, with descriptions for each domain and competency. Six highlighted areas of considerations for medical educators are the variations in nomenclature, the distinctiveness of digital health, the concept of digital health literacy, curriculum space and implementation, the inclusion of discretionary learning outcomes, and socioeconomic inequities in digital health education. Conclusions and Relevance: This evidence-informed and consensus-guided framework will play an important role in enabling medical institutions to better prepare future physicians for the ongoing digital transformation in health care. Medical schools are encouraged to adopt and adapt this framework to align with their needs, resources, and circumstances.

Shining a light on cell biology of the nucleus with single-cell sequencing

van den Berg, J., Zeller, P. — Tue, 01 Apr 2025 17:45:38 +0200

From the preservation of genomic integrity to the regulation of RNA translation, nearly all cellular processes are regulated in a cell context-dependent manner. To fully understand the context-specific function of involved nuclear processes, a vast number of single-cell sequencing technologies were developed over the last decade. This instrumental work demonstrated the heterogeneity between cell types and individual cells, bringing about new understanding of nuclear mechanisms and their crosstalk to cell states. In this review, we will cover new technological advances and their exciting applications as well as future opportunities to discover new nuclear processes and the crosstalk between them.

Non-classical neutrophil extracellular traps induced by PAR2-signaling proteases

Bryzek, D., Gasiorek, A., Kowalczyk, D., et al. — Mon, 01 Dec 2025 17:45:38 +0100

Neutrophil extracellular traps (NETs) are associated with diseases linked to aberrant coagulation. The blood clotting cascade involves a series of proteases, some of which induce NET formation via a yet unknown mechanism. We hypothesized that this formation involves signaling via a factor Xa (FXa) activation of the protease-activated receptor 2 (PAR2). Our findings revealed that NETs can be triggered in vitro by enzymatically active proteases and PAR2 agonists. Intravital microscopy of the liver vasculature revealed that both FXa infusion and activation of endogenous FX promoted NET formation, effects that were prevented by the FXa inhibitor, apixaban. Unlike classical NETs, these protease-induced NETs lacked bactericidal activity and their proteomic signature indicates their role in inflammatory disorders, including autoimmune diseases and carcinogenesis. Our findings suggest a novel mechanism of NET formation under aseptic conditions, potentially contributing to a self-amplifying clotting and NET formation cycle. This mechanism may underlie the pathogenesis of disseminated intravascular coagulation and other aseptic conditions. (Figure presented.)

End-To-End Deep Learning Explains Antimicrobial Resistance in Peak-Picking-Free MALDI-MS Data

Lassen, J. K., Villesen, P. — Sat, 01 Feb 2025 17:45:38 +0100

Mass spectrometry is used to determine infectious microbial species in thousands of clinical laboratories across the world. The vast amount of data allows modern data analysis methods that harvest more information and potentially answer new questions. Here, we present an end-to-end deep learning model for predicting antibiotic resistance using raw matrix assisted laser desorption ionization mass spectrometry (MALDI-MS) data. We used a 1-dimensional convolutional neural network to model (almost) raw data, skipping conventional peak-picking and directly predict resistance. The model’s performance is state-of-the-art, having AUCs between 0.93 and 0.99 in all antimicrobial resistance phenotypes and validates across time and location. Feature attribution values highlight important insights into the model and how the end-to-end workflow can be improved further. This study showcases that reliable resistance phenotyping using MALDI-MS data is attainable and highlights the gains of using end-to-end deep learning for spectrometry data.

Xanthine oxidase-lactoperoxidase system

Sat, 01 Feb 2025 17:45:38 +0100

Xanthine oxidase (XO) and lactoperoxidase (LPO) are highly abundant enzymes in milk. Their substrates, xanthine and thiocyanate, are found in elevated amounts in infant saliva, leading to a proposed interaction between milk and saliva referred to as the XO-LPO system. This system is suggested to generate reactive oxygen and nitrogen species with potential antibacterial effects. The antibacterial activity of the XO-LPO system was assessed on bacteria cultured from the oral cavities of five infants, where a reduction in bacterial growth rate was observed at 40 µg mL⁻¹ of each enzyme and with complete inhibition achieved at 200 µg mL⁻¹. Gene expression analysis showed that XO-LPO treatment led to downregulation of several reactive oxygen species-related genes, suggesting a transient bacterial stress response. The study also observed downregulation of key glycolytic enzymes, indicating that XO-LPO treatment affects bacterial metabolism at transcriptional level, suggesting a possible mechanism of action for the XO-LPO system. Collectively, these findings offer new insights into the XO-LPO system, revealing novel aspects of the interaction between lactation and microbiome influence.

Bradykinesia and postural instability in a model of prodromal synucleinopathy with α-synuclein aggregation initiated in the gigantocellular nuclei

Theologidis, V., Ferreira, S. A., Jensen, N. M., et al. — Mon, 17 Feb 2025 17:45:38 +0100

α-Synuclein (aSyn) accumulation within the extra-nigral neuronal populations in the brainstem, including the gigantocellular nuclei (GRN/Gi) of reticular formation, is a recognized feature during the prodromal phase of Parkinson disease (PD). Accordingly, there is a burgeoning interest in animal model development for understanding the pathological significance of extra-nigral synucleinopathy, in relation to motor and/or non-motor symptomatology in PD. Here, we report an experimental paradigm for the induction of aSyn aggregation in brainstem, with stereotaxic delivery of pre-formed fibrillar (PFF) aSyn in the pontine GRN of transgenic mice expressing the mutant human Ala53Thr aSyn (M83 line). Our data show that PFF aSyn-induced aggregate pathology in GRN and distinct nuclei of subcortical motor system leads to progressive decline in home cage activity, which was accompanied by postural instability and impaired motor coordination. The progressive accumulation of aSyn pathology in brainstem and motor neurons in lumbar spinal cord heralded the onset of a moribund stage, which culminated in impaired survival. Collectively, our observations suggest an experimental framework for studying the pathological significance of aSyn aggregation in GRN in relation to features of movement disability in PD. With further refinements, we anticipate that this model holds promise as a test-bed for translational research in PD and related disorders.

Sulfamerazine as a Potential Modulator against α-Synuclein Aggregation and Associated Toxicity

Singh, P., Kadam, N. Y., Panigrahi, R., et al. — Wed, 05 Mar 2025 17:45:38 +0100

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder. The presence of Lewy bodies, primarily consisting of amyloid aggregates of the protein α-synuclein (α-Syn), is a common feature seen in dopaminergic neurons in (PD) patients. In the present study, we screened 2320 FDA-approved drugs and found 3 lead molecules, sulfamerazine, lathosterol, and tamoxifen, that reproducibly inhibited α-Syn fibrillation. Dose-response studies showed that sulfamerazine and lathosterol are relatively more potent than tamoxifen in inhibiting α-Syn aggregation. Among the lead compounds, sulfamerazine showed a significant reduction in α-Syn aggregation and associated toxicity in Caenorhabditis elegans model of PD. Sulfamerazine also reduced the accumulation of α-Syn aggregates in neuronal SH-SY5Y cells. Microscale thermophoresis confirmed the binding of sulfamerazine to α-Syn. NMR studies corroborated the binding of sulfamerazine with α-Syn and show that upon interaction, α-Syn is sequestered into large soluble dispersed assemblies, which is similar to as seen in transmission electron microscopy. We conclude that sulfamerazine and its derivatives hold promise as therapeutic agents against Parkinson's disease.

In vitro investigations on the impact of fermented dairy constituents on fecal microbiota composition and fermentation activity.

Li, Q., Marietou, A., Andersen, F. F., et al. — Sat, 01 Mar 2025 17:45:38 +0100

Fermented dairy constitutes a major dietary source and contains lactose as the main carbohydrate and living starter cultures, which can encounter the intestinal microbiota after ingestion. To investigate whether dairy-related nutritional and microbial modulation impacted intestinal microbiota composition and activity, we employed static fecal microbiota fermentations and a dairy model system consisting of lactose and Streptococcus thermophilus wild type and β-galactosidase deletion mutant. In addition, we conducted single-culture validation studies. 16S rRNA gene-based microbial community analysis showed that lactose increased the abundance of Bifidobacteriaceae and Anaerobutyricum and Faecalibacterium spp. The supplied lactose was hydrolyzed within 24 h of fermentation and led to higher expression of community-indigenous β-galactosidases. Targeted protein analysis confirmed that bifidobacteria contributed most β-galactosidases together with other taxa, including Escherichia coli and Anaerobutyricum hallii. Lactose addition led to higher (P < 0.05) levels of butyrate compared to controls, likely due to lactate-based cross-feeding and direct lactose metabolism by butyrate-producing Anaerobutyricum and Faecalibacterium spp. Representatives of both genera used lactose to produce butyrate in single cultures. When supplemented at around 5.5 log cells mL⁻¹, S. thermophilus or its β-galactosidase-negative mutant outnumbered the indigenous Streptococcaceae population at the beginning of fermentation but had no impact on lactose utilization and final short-chain fatty acid profiles.

Familial confounding in the associations between maternal health and autism

Khachadourian, V., Arildskov, E. S., Grove, J., et al. — Fri, 31 Jan 2025 17:45:38 +0100

Evidence suggests that maternal health in pregnancy is associated with autism in the offspring. However, most diagnoses in pregnant women have not been examined, and the role of familial confounding remains unknown. Our cohort included all children born in Denmark between 1998 and 2015 (n = 1,131,899) and their parents. We fitted Cox proportional hazard regression models to estimate the likelihood of autism associated with each maternal prenatal ICD-10 diagnosis, accounting for disease chronicity and comorbidity, familial correlations and sociodemographic factors. We examined the evidence for familial confounding using discordant sibling and paternal negative control designs. Among the 1,131,899 individuals in our sample, 18,374 (1.6%) were diagnosed with autism by the end of follow-up. Across 236 maternal diagnoses we tested (prevalence ≥0.1%), 30 were significantly associated with autism after accounting for sociodemographic factors, disorder chronicity and comorbidity, and correction for multiple testing. This included obstetric, cardiometabolic and psychiatric disorders (for example, diabetes in pregnancy (hazard ratio (HR) 1.19, 95% confidence interval (CI) 1.08-1.31) and depression (HR 1.49, 95% CI 1.27-1.75)), previously shown to be associated with autism. Family-based analyses provided strong evidence for familial confounding in most of the observed associations. Our findings indicate pervasive associations between maternal health in pregnancy and offspring autism and underscore that these associations are largely attributable to familial confounding.

The neuroprotective effect of human umbilical cord MSCs-derived secretome against α-synuclein aggregates on the blood-brain barrier

Tue, 01 Apr 2025 17:45:38 +0200

The blood-brain barrier (BBB) is a specialized network that maintains central nervous system homeostasis. Disruption of the BBB can lead to neuronal damage and contribute to neurodegenerative diseases like Parkinson's disease (PD), characterized by alpha-synuclein (αSN) aggregation, which forms intracellular inclusions. Mesenchymal stem cells (MSCs) have shown promise in alleviating the severity of neurological diseases through their paracrine secretions. However, the impact of MSCs secretome on the BBB remains largely unclear. In this study, we investigated the effect of human umbilical cord-derived MSCs (hUC-MSCs) secretome on the BBB in the presence of toxic αSN-aggregates (αSN-AGs). Using in vitro BBB models established through mono- and co-culture systems of hCMEC/D3 cells, we assessed the influence of the secretome on the cytotoxicity and inflammatory responses induced by αSN-AGs. Our results demonstrate that the hUC-MSCs secretome exerts protective effects by mitigating the toxic effects of αSN-AGs on the BBB. Specifically, this study shows a notable reduction in cytotoxicity and inflammation. Our findings highlight the potential of hUC-MSCs secretome as a promising candidate for innovative, cell-free therapies in PD treatment. Furthermore, we propose an optimized method for isolating MSCs from umbilical cord tissue, aimed at facilitating future research on the therapeutic applications of these cells.

A randomized controlled trial investigating the neurocognitive effects of Lacprodan® PL-20, a phospholipid-rich milk protein concentrate, in elderly participants with age-associated memory impairment

Scholey, A. B., Camfield, D. A., Hughes, M. E., et al. — Tue, 26 Nov 2013 17:45:38 +0100

Background: Age-related cognitive decline (ARCD) is of major societal concern in an ageing population, with the development of dietary supplements providing a promising avenue for amelioration of associated deficits. Despite initial interest in the use of phospholipids (PLs) for ARCD, in recent years there has been a hiatus in such research. Because of safety concerns regarding PLs derived from bovine cortex, and the equivocal efficacy of soybean-derived PLs, there is an important need for the development of new PL alternatives. Phospholipids derived from milk proteins represent one potential candidate treatment.Methods: In order to reduce the effects of age-associated memory impairment (AAMI) the Phospholipid Intervention for Cognitive Ageing Reversal (PLICAR) was developed to test the efficacy of a milk protein concentrate rich in natural, non-synthetic milk phospholipids (Lacprodan® PL-20). PLICAR is a randomized, double-blind, placebo-controlled parallel-groups study where 150 (N = 50/group) AAMI participants aged > 55 years will be randomized to receive a daily supplement of Lacprodan® PL-20 or one of two placebos (phospholipid-free milk protein concentrate or inert rice starch) over a 6-month (180-day) period. Participants will undergo testing at baseline, 90 days and 180 days. The primary outcome is a composite memory score from the Rey Auditory Verbal Learning Test. Secondary outcomes include cognitive (verbal learning, working memory, prospective and retrospective memory, processing speed and attention), mood (depression, anxiety, stress and visual analogue scales), cardiovascular (blood pressure, blood velocity and pulse wave pressure), gastrointestinal microbiota and biochemical measures (oxidative stress, inflammation, B vitamins and Homocysteine, glucoregulation and serum choline). Allelic differences in the Apolipoprotein E and (APOE) and Methylenetetrahydrofolate reductase (MTHFR) gene will be included for subgroup analysis. A subset (N = 60; 20/group)) will undergo neuroimaging using functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) in order to further explore in vivo central mechanisms of action of Lacprodan® PL-20. This study will enable evaluation of the efficacy of milk-derived phospholipids for AAMI, and their mechanisms of action.Trial Registration: The trial is jointly funded by Arla Foods and Swinburne University of Technology, currently recruiting and is registered on the Australian New Zealand Clinical Trials Registry as ACTRN12613000347763.

Dietary milk-fat-globule membrane affects resistance to diarrheagenic escherichia coli in healthy adults in a randomized, placebo-controlled, double-blind study

Ten Bruggencate, S. J., Frederiksen, P. D., Pedersen, S. M., et al. — Fri, 01 Jan 2016 17:45:38 +0100

Background: The milk-fat-globule membrane (MFGM) contains phospholipids and membrane glycoproteins that have been shown to affect pathogen colonization and gut barrier integrity. Objective: In the present study, we determined whether commercial heat-treated MFGM can increase resistance to diarrheagenic Escherichia coli. Methods: A randomized, placebo-controlled, double-blind, 4-wk parallel-intervention study was conducted in healthy adults. Participants were randomly assigned to a milk protein concentrate rich in MFGM [10 g Lacprodan PL-20 (Arla Foods Ingredients Group P/S), twice daily; n = 30; MFGM group) or a control [10 g Miprodan 30 (sodium caseinate), twice daily; n = 28]. After 2 wk, participants were orally challenged with live, attenuated diarrheagenic E. coli (1010 colonyforming units). Primary outcomes were infection-induced diarrhea and fecal diarrheagenic E. coli excretion. Secondary outcomes were gastrointestinal symptoms [Gastrointestinal Symptom Rating Scale (GSRS)], stool frequency, and stool consistency (Bristol Stool Scale). Results: Diarrheagenic E. coli resulted in increased fecal output, lower relative fecal dry weight, increased fecal E. coli numbers, and an increase in stool frequency and gastrointestinal complaints at day 1 after challenge. MFGM significantly decreased the E. coli-induced changes in reported stool frequency (1.1 ± 0.1 stools/d in the MFGM group; 1.6 ± 0.2 stools/d in the control group; P = 0.04) and gastrointestinal complaints at day 2 (1.1 ± 0.5 and 2.5 ± 0.6 GSRS scores in the MFGM and control groups, respectively; P = 0.05). MFGM did not affect fecal wet weight and E. coli excretion at day 2 after challenge. Conclusions: The attenuated diarrheagenic E. coli strain transiently induced mild symptoms of a food-borne infection, with complete recovery of reported clinical symptoms within 2 d. The present diarrheagenic E. coli challenge trial conducted in healthy adults indicates that a milk concentrate rich in natural, bioactive phospho- and sphingolipids from the MFGM may improve in vivo resistance to diarrheagenic E. coli. This trial was registered at clinicaltrials.gov as NCT01800396.

Effects of milk-based phospholipids on cognitive performance and subjective responses to psychosocial stress

Boyle, N. B., Dye, L., Arkbåge, K., et al. — Tue, 01 Jan 2019 17:45:38 +0100

Objectives: The aim of this study was to examine the stress-buffering potential of phospholipid (PL) intake on cognitive performance and neuroendocrine and psychological responses under conditions of psychosocial stress in a high-stress vulnerable (perfectionist) sample. Methods: Fifty-four high-perfectionist men consumed a 6-wk daily intake of a bovine milk–derived PL (2.7 g/d) or placebo drink in a randomized, double-blind, placebo-controlled, parallel groups design. Working memory, executive control function, and acute physiological/subjective responses to an acute psychosocial stressor were examined before and after the 6-wk PL or placebo intake. Results: PL intake improved post-stress reaction time performance on an attention-switching task (P = 0.01). No significant attenuation of the salivary cortisol stress response was shown. PL intake significantly increased mid-stress induction energetic arousal (P = 0.03). A non-significant reduction in anticipatory subjective stress was reported after PL intake (P = 0.06). Systolic and diastolic blood pressures (P < 0.04 and P = 0.01, respectively) were significantly augmented in the PL condition. Conclusions: Dietary intake of bovine milk PLs conferred cognitive performance benefit under conditions of psychosocial stress but failed to moderate cortisol response. Moderation of subjective response to stress exposure may have underpinned this performance protection.

Genomics yields biological and phenotypic insights into bipolar disorder

O'Connell, K. S., Koromina, M., van der Veen, T., et al. — Wed, 01 Jan 2025 17:45:38 +0100

Bipolar disorder is a leading contributor to the global burden of disease1. Despite high heritability (60-80%), the majority of the underlying genetic determinants remain unknown2. We analysed data from participants of European, East Asian, African American and Latino ancestries (n = 158,036 cases with bipolar disorder, 2.8 million controls), combining clinical, community and self-reported samples. We identified 298 genome-wide significant loci in the multi-ancestry meta-analysis, a fourfold increase over previous findings3, and identified an ancestry-specific association in the East Asian cohort. Integrating results from fine-mapping and other variant-to-gene mapping approaches identified 36 credible genes in the aetiology of bipolar disorder. Genes prioritized through fine-mapping were enriched for ultra-rare damaging missense and protein-truncating variations in cases with bipolar disorder4, highlighting convergence of common and rare variant signals. We report differences in the genetic architecture of bipolar disorder depending on the source of patient ascertainment and on bipolar disorder subtype (type I or type II). Several analyses implicate specific cell types in the pathophysiology of bipolar disorder, including GABAergic interneurons and medium spiny neurons. Together, these analyses provide additional insights into the genetic architecture and biological underpinnings of bipolar disorder.

Inorganic phosphate transporter PiT2 and phosphate homeostasis

Segelund, E. B., Kristensen, M. D., Holste, S., Lundby, J. M. B., Pedersen, L. — Thu, 07 Nov 2024 17:45:38 +0100

Exploiting O-GlcNAc dyshomeostasis to screen O-GlcNAc transferase intellectual disability variants

Yuan, H., Mitchell, C. W., Ferenbach, A. T., et al. — Tue, 14 Jan 2025 17:45:38 +0100

O-GlcNAcylation is an essential protein modification catalyzed by O-GlcNAc transferase (OGT). Missense variants in OGT are linked to a novel intellectual disability syndrome known as OGT congenital disorder of glycosylation (OGT-CDG). The mechanisms by which OGT missense variants lead to this heterogeneous syndrome are not understood, and no unified method exists for dissecting pathogenic from non-pathogenic variants. Here, we develop a double-fluorescence strategy in mouse embryonic stem cells to measure disruption of O-GlcNAc homeostasis by quantifying the effects of variants on endogenous OGT expression. OGT-CDG variants generally elicited a lower feedback response than wild-type and Genome Aggregation Database (gnomAD) OGT variants. This approach was then used to dissect new putative OGT-CDG variants from pathogenic background variants in other disease-associated genes. Our work enables the prediction of pathogenicity for rapidly emerging de novo OGT-CDG variants and points to reduced disruption of O-GlcNAc homeostasis as a common mechanism underpinning OGT-CDG.

The structural organisation of pentraxin-3 and its interactions with heavy chains of inter-α-inhibitor regulate crosslinking of the hyaluronan matrix

Shah, A., Zhang, X., Snee, M., et al. — Tue, 01 Apr 2025 17:45:38 +0200

Pentraxin-3 (PTX3) is an octameric protein, comprised of eight identical protomers, that has diverse functions in reproductive biology, innate immunity and cancer. PTX3 interacts with the large polysaccharide hyaluronan (HA) to which heavy chains (HCs) of the inter-α-inhibitor (IαI) family of proteoglycans are covalently attached, playing a key role in the (non-covalent) crosslinking of HC•HA complexes. These interactions stabilise the cumulus matrix, essential for ovulation and fertilisation in mammals, and are also implicated in the formation of pathogenic matrices in the context of viral lung infections. To better understand the physiological and pathological roles of PTX3 we have analysed how its quaternary structure underpins HA crosslinking via its interactions with HCs. A combination of X-ray crystallography, cryo-electron microscopy (cryo-EM) and AlphaFold predictive modelling revealed that the C-terminal pentraxin domains of the PTX3 octamer are arranged in a central cube, with two long extensions on either side, each formed from four protomers assembled into tetrameric coiled-coil regions, essentially as described by (Noone et al., 2022; doi:10.1073/pnas.2208144119). From crystallography and cryo-EM data, we identified a network of inter-protomer salt bridges that facilitate the assembly of the octamer. Small angle X-ray scattering (SAXS) validated our model for the octameric protein, including the analysis of two PTX3 constructs: a tetrameric 'Half-PTX3' and a construct missing the 24 N-terminal residues (Δ1-24-PTX3). SAXS determined a length of ∼520 Å for PTX3 and, combined with 3D variability analysis of cryo-EM data, defined the flexibility of the N-terminal extensions. Biophysical analyses revealed that the prototypical heavy chain HC1 does not interact with PTX3 at pH 7.4, consistent with our previous studies showing that, at this pH, PTX3 only associates with HC•HA complexes if they are formed in its presence. However, PTX3 binds to HC1 at acidic pH, and can also be incorporated into pre-formed HC•HA complexes under these conditions. This provides a novel mechanism for the regulation of PTX3-mediated HA crosslinking (e.g., during inflammation), likely mediated by a pH-dependent conformational change in HC1. The PTX3 octamer was found to associate simultaneously with up to eight HC1 molecules and, thus, has the potential to form a major crosslinking node within HC•HA matrices, i.e., where the physical and biochemical properties of resulting matrices could be tuned by the HC/PTX3 composition.