Biology subjects

Wiberg, A.

Publications and source records attributed to Wiberg, A..

7 recordsLinked to original sources

bioRxiv2021

Variants in ALDH1A2 reveal an anti-inflammatory role for retinoic acid and a new class of disease-modifying drugs in osteoarthritis

Over 40% of individuals will develop osteoarthritis (OA) during their lifetime, yet there are currently no licensed disease modifying treatments for this disabling condition. Common polymorphic variants in ALDH1A2, that encodes the key enzyme in the synthesis of all-trans retinoic acid (atRA), have been associated with severe hand OA. In this study, we sought to elucidate the biological significance of this association. We first confirmed that ALDH1A2 risk variants were associated with hand OA in UK Biobank. Articular cartilage was acquired from 33 consenting individuals with hand OA at the time of routine hand OA surgery. They were stratified by genotype and RNA sequencing performed. A reciprocal relationship between ALDH1A2 mRNA and inflammatory genes was observed. Articular cartilage injury up-regulates similar inflammatory genes by a process that we have previously termed mechanoflammation, and which we believe is a primary driver of OA. Cartilage injury was also associated with a concomitant drop in atRA-dependent genes, indicative of cellular atRA levels, and both responses to injury were reversed using talarozole, a retinoic acid metabolism blocking agent (RAMBA). Suppression of mechanoflammation by talarozole was mediated by a peroxisome proliferator activated receptor (PPAR)-{gamma} dependent mechanism. Talarozole, delivered by minipump, was able to suppress mechano-inflammatory genes in articular cartilage in vivo 6h after mouse knee joint destabilization, and reduced cartilage degradation and osteophyte formation after 4 weeks. These data show that boosting atRA suppresses mechanoflammation in the articular cartilage in vitro and in vivo, and identifies RAMBAs as potential disease modifying drugs in OA. One Sentence SummaryAnalysis of hand OA cartilage stratified by ALDH1A2 polymorphic variants reveals a targetable, anti-inflammatory role for retinoic acid in OA.

molecular biology↗

bioRxiv2020

An SNP variant MT1-MMP with a defect in its collagenolytic activity confers the fibrotic phenotype of Dupuytren's Disease

Dupuytrens Disease (DD) is a common fibroproliferative disease of the palmar fascia. We previously identified a strong association with a non-synonymous variant (rs1042704, pD273N) in MMP14 (encoding MT1-MMP). We investigated the functional consequences of this variant, and demonstrated that the variant MT1-MMP (MT1-N273) exhibits only 17% of cell surface collagenolytic activity compared to the ancestral enzyme (MT1-D273). Cells expressing both MT1-D273 and MT1-N273 in a 1:1 ratio, mimicking the heterozygous state, possess 38% of the collagenolytic activity compared to the cells expressing MT1-D273, suggesting that MT1-N273 acts in a dominant negative manner. Consistent with this hypothesis, patient-derived DD myofibroblasts expressing MT1-N273 demonstrated around 30% of full collagenolytic activity regardless of the heterozygous or homozygous state. 3D-molecular envelope modelling using small angle X-ray scattering demonstrated altered positioning of the catalytic domain within dimeric molecules. Taken together, our data suggest that rs1042704 directly contributes to the fibrotic phenotype of DD.

biochemistry↗

bioRxiv2020

Genome-wide association analysis and replication in 810,625 individuals identifies novel therapeutic targets for varicose veins

BackgroundVaricose veins (VVs) affect one-third of Western society, with a significant subset of patients developing venous ulceration, and ongoing management of venous leg ulcers costing around $14.9 billion annually in the USA. There is no current medical management for VVs, with approaches limited to compression stockings, ablation techniques, or open surgery for more advanced disease. A significant proportion of patients report a positive family history, and heritability is ~17%, suggesting a strong genetic component. We aimed to identify novel therapeutic targets by improving our understanding of the aetiopathology and genetic architecture of VVs. MethodsWe performed the largest two-stage genome-wide association study of VVs in 401,656 subjects from UK Biobank, and replication in 408,969 subjects from 23andMe (total 135,514 varicose veins cases and 675,111 controls). We constructed a genetic risk score for VVs to investigate its use as a prognostic tool. Genes and pathways were prioritised using a suite of bioinformatic tools, and therapeutic targets identified using the Open Targets Platform. ResultsWe discovered 49 signals at 46 susceptibility loci associated with VVs, including 29 previously unreported genetic associations (28 susceptibility loci). We demonstrated that patients with VVs requiring surgery have a higher genetic risk score than those managed non-surgically. We map 237 genes to these loci, many of which are biologically relevant and tractable to therapeutic targeting or repurposing (notably VEGFA, COL27A1, EFEMP1, PPP3R1 and NFATC2). Tissue enrichment analyses implicated vascular tissue, and several genes were enriched in biological pathways relating to extracellular matrix biology, inflammation, angiogenesis, lymphangiogenesis, vascular smooth muscle cell migration, and apoptosis. ConclusionsGenes and pathways identified represent biologically plausible contributors to the pathobiology of VVs, identifying promising candidates for further investigation of venous biology and potential therapeutic targets. We have provided the proof-of-principle that genetic risk score correlates with disease severity, which represents a first step in personalised medicine approaches to varicose veins.

genetics↗

bioRxiv2019

Molecular and cellular correlates of human nerve regeneration: ADCYAP1 encoding PACAP enhances sensory neuron outgrowth

We only have a rudimentary understanding of the molecular and cellular determinants of human nerve regeneration. Here, we use carpal tunnel syndrome (CTS) as a human model system to prospectively evaluate correlates of neural regeneration and their relationship with clinical recovery after decompression surgery. At 6 months post-surgery, we noted a significant improvement of median nerve neurophysiological and somatosensory function. Serial skin biopsies revealed a partial recovery of intraepidermal innervation, whose extent correlated with symptom improvement. In myelinated afferents, nodal length increased postoperatively. Transcriptional profiling of the skin revealed 23 differentially expressed genes following decompression, with ADCYAP1 (encoding PACAP) being the most strongly upregulated and showing an association with regeneration of intraepidermal nerve fibres. Using human induced pluripotent stem cell-derived sensory neurons, we confirmed that PACAP significantly enhances axon outgrowth in vivo. Since PACAP signals through G-protein receptors, this pathway provides an interesting therapeutic target for human sensory nerve regeneration.

neuroscience↗

bioRxiv2019

Genetic variants of calcium and vitamin D metabolism in kidney stone disease

Kidney stone disease (nephrolithiasis) is a major clinical and economic health burden1,2 with a heritability of ~45-60%3. To identify genetic variants associated with nephrolithiasis we performed genome-wide association studies (GWAS) and meta-analysis in British and Japanese populations, including 12,123 nephrolithiasis cases and 416,928 controls. Twenty loci associated with nephrolithiasis were identified, ten of which are novel. A novel CYP24A1 locus is predicted to affect vitamin D metabolism and five loci, DGKD, DGKH, WDR72, GPIC1, and BCR, are predicted to influence calcium-sensing receptor (CaSR) signaling. In a validation cohort of nephrolithiasis patients the CYP24A1-associated locus correlated with serum calcium concentration and number of kidney stone episodes, and the DGKD-associated locus correlated with urinary calcium excretion. Moreover, DGKD knockdown impaired CaSR-signal transduction in vitro, an effect that was rectifiable with the calcimimetic cinacalcet. Our findings indicate that genotyping may inform risk of incident kidney stone disease prior to vitamin D supplementation and facilitate precision-medicine approaches, by targeting CaSR-signaling or vitamin D activation pathways in patients with recurrent kidney stones.

genomics↗

bioRxiv2018

Characterization of the endocrine pancreas in Type 1 Diabetes: islet size is maintained but islet number is markedly reduced

Insulin deficiency in type 1 diabetes (T1D) is generally considered a consequence of specific beta-cell loss. Since healthy pancreatic islets consist of ~65% beta cells, this would lead to reduced islet size if the beta cells are not replaced by other cells or tissue. The number of islets per pancreas volume (islet density) would not be affected.\n\nIn this study, we compared the islet density, size, and size distribution in subjects with recent-onset or long-standing T1D, with that in matched non-diabetic subjects. Results show that subjects with T1D, regardless of disease duration, had a dramatically reduced islet number per mm2, while the islet size was similar in all groups. Insulin-negative islets in T1D subjects were dominated by glucagon-positive cells that frequently had lost the alpha-cell transcription factor ARX while instead expressing PDX1, normally expressed in beta cells.\n\nBased on our findings, we propose that failure during childhood to establish a sufficient islet number to reach the beta-cell mass needed to cope with episodes of increased insulin demand contributes to T1D susceptibility. Exhaustion induced by relative lack of beta cells could then potentially drive beta-cell dedifferentiation to alpha-cells, explaining the preserved islet size observed in T1D compared to controls.

pathology↗

bioRxiv2018

Human Handedness: Genetics, Microtubules, Neuropsychiatric Diseases and Brain Language Areas

BackgroundThe skew in distribution of handedness is a uniquely human trait, and has fascinated researchers for centuries. The heritability of handedness is estimated at 25%, but defining genetic variants contributing to this trait has so far proved elusive.\n\nMethodsWe performed GWAS of self-reported handedness in UK Biobank, a prospective cohort study of [~]500,000 individuals. Furthermore, we investigated correlations between our associated SNPs and brain imaging-derived phenotypes (IDPs) from >9,000 individuals in UK Biobank, as well as between self-reported handedness and IDPs.\n\nResultsOur association study of 38,322 left-handers vs 356,567 right-handers (excluding ambidextrous participants) revealed three genome-wide significant loci (rs199512, 17q21.31, p=4.1x10-9; rs45608532, 22q11.22, p=1.4x10-8; rs13017199, 2q34, p=3.3x10-8). In the imaging study, we found strong associations between rs199512 and diffusion MRI measures mainly in white matter tracts connecting language-related brain regions (p<2.0x10-6). Direct investigation between handedness and IDPs revealed numerous associations with functional connectivity between the same language-related areas of the brain. A second GWAS of non-right handers (n=44,631) vs right-handers (n=356,567) revealed an additional locus: rs3094128, 6p21.33, p=2.9x10-8. Three of the four associated loci (2q34, 17q21.31, 6p21.33) contain genes that encode microtubule-related proteins that are highly expressed in the brain: MAP2, MAPT and TUBB. These genes are strongly implicated in the pathogenesis of diseases that are known to affect an excess of left-handed people, including schizophrenia.\n\nConclusionsThis is the first GWAS to identify genome-wide significant loci for human handedness in the general population, and the genes at these loci have biological plausibility in contributing to neurodevelopmental lateralization of brain organisation, which appears to predispose both to left-handedness and to certain neurodegenerative and psychiatric diseases.

neuroscience↗