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- Bustamante, Mariona, et al.
(author)
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A genome-wide association meta-analysis of diarrhoeal disease in young children identifies FUT2 locus and provides plausible biological pathways.
- 2016
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In: Human molecular genetics. - : Oxford University Press (OUP). - 1460-2083 .- 0964-6906. ; 25:18, s. 4127-4142
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Journal article (peer-reviewed)abstract
- More than a million childhood diarrhoeal episodes occur worldwide each year, and in developed countries a considerable part of them are caused by viral infections. In this study, we aimed to search for genetic variants associated with diarrhoeal disease in young children by meta-analyzing genome-wide association studies, and to elucidate plausible biological mechanisms. The study was conducted in the context of the Early Genetics and Lifecourse Epidemiology (EAGLE) consortium. Data about diarrhoeal disease in two time windows (around 1 year of age and around 2 years of age) was obtained via parental questionnaires, doctor interviews or medical records. Standard quality control and statistical tests were applied to the 1000 Genomes imputed genotypic data. The meta-analysis (N=5758) followed by replication (N=3784) identified a genome-wide significant association between rs8111874 and diarrhoea at age 1 year. Conditional analysis suggested that the causal variant could be rs601338 (W154X) in the FUT2 gene. Children with the A allele, which results in a truncated FUT2 protein, had lower risk of diarrhoea. FUT2 participates in the production of histo-blood group antigens and has previously been implicated in the susceptibility to infections, including Rotavirus and Norovirus Gene-set enrichment analysis suggested pathways related to the histo-blood group antigen production, and the regulation of ion transport and blood pressure. Among others, the gastrointestinal tract, and the immune and neuro-secretory systems were detected as relevant organs. In summary, this genome-wide association meta-analysis suggests the implication of the FUT2 gene in diarrhoeal disease in young children from the general population.
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| 2. |
- Charbord, Jeremie, et al.
(author)
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In vivo screen identifies a SIK inhibitor that induces beta cell proliferation through a transient UPR
- 2021
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In: Nature Metabolism. - : Springer Science and Business Media LLC. - 2522-5812. ; 3:5, s. 682-700
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Journal article (peer-reviewed)abstract
- It is known that beta cell proliferation expands the beta cell mass during development and under certain hyperglycemic conditions in the adult, a process that may be used for beta cell regeneration in diabetes. Here, through a new high-throughput screen using a luminescence ubiquitination-based cell cycle indicator (LUCCI) in zebrafish, we identify HG-9-91-01 as a driver of proliferation and confirm this effect in mouse and human beta cells. HG-9-91-01 is an inhibitor of salt-inducible kinases (SIKs), and overexpression of Sik1 specifically in beta cells blocks the effect of HG-9-91-01 on beta cell proliferation. Single-cell transcriptomic analyses of mouse beta cells demonstrate that HG-9-91-01 induces a wave of activating transcription factor (ATF)6-dependent unfolded protein response (UPR) before cell cycle entry. Importantly, the UPR wave is not associated with an increase in insulin expression. Additional mechanistic studies indicate that HG-9-91-01 induces multiple signalling effectors downstream of SIK inhibition, including CRTC1, CRTC2, ATF6, IRE1 and mTOR, which integrate to collectively drive beta cell proliferation. A high-throughput chemical screen identifies the salt-inducible kinase inhibitor HG-9-91-01 as a driver of beta cell proliferation, acting through an ATF6-dependent unfolded protein response.
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| 4. |
- Schmidt, Vanessa, et al.
(author)
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SORLA facilitates insulin receptor signaling in adipocytes and exacerbates obesity
- 2016
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In: Journal of Clinical Investigation. - : American Society for Clinical Investigation. - 0021-9738 .- 1558-8238. ; 126:7, s. 2706-2720
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Journal article (peer-reviewed)abstract
- In humans, genetic variation of sortilin-related receptor, L(DLR class) A repeats containing (SORL1), which encodes the intracellular sorting receptor SORLA, is a major genetic risk factor for familial and sporadic forms of Alzheimer's disease. Recent GWAS analysis has also associated SORL1 with obesity in humans and in mouse models, suggesting that this receptor may play a role in regulating metabolism. Here, using mouse models with genetic loss or tissue-specific overexpression of SORLA as well as data from obese human subjects, we observed a gene-dosage effect that links SORLA expression to obesity and glucose tolerance. Overexpression of human SORLA in murine adipose tissue blocked hydrolysis of triacylglycerides and caused excessive adiposity. In contrast, Sorl1 gene inactivation in mice accelerated breakdown of triacylglycerides in adipocytes and protected animals from diet-induced obesity. We then identified the underlying molecular mechanism whereby SORLA promotes insulin-induced suppression of lipolysis in adipocytes. Specifically, we determined that SORLA acts as a sorting factor for the insulin receptor (IR) that redirects internalized receptor molecules from endosomes to the plasma membrane, thereby enhancing IR surface expression and strengthening insulin signal reception in target cells. Our findings provide a molecular mechanism for the association of SORL1 with human obesity and confirm a genetic link between neurodegeneration and metabolism that converges on the receptor SORLA.
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