bims-obesme Biomed News
on Obesity metabolism
Issue of 2026–06–07
nine papers selected by
Xiong Weng, University of Edinburgh



  1. Nat Commun. 2026 Jun 03.
      The mechanisms connecting the human fat depots, subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT), to metabolic dysfunction-associated steatotic liver disease (MASLD) remain elusive. We hypothesize that in individuals with obesity, a decreased degree of adipocyte differentiation may contribute to ectopic fat accumulation in the liver, seen in MASLD. Here we show, using single nucleus RNA-sequencing from adipose tissue biopsies, that the predicted degree of VAT adipocyte differentiation is decreased in individuals with MASLD, with an attenuated impact observed in SAT adipocytes. Next, we discover that regional variants of the VAT adipocyte differentiation gene set explain a substantial proportion (17%) of MASLD heritability. These genes largely overlap (>50%) with adipocyte genes differentially expressed by MASLD, regulated by variants in cis. Finally, we show that these genes are linked to smaller adipocyte size. Together, our findings reveal that a decreased predicted degree of VAT adipocyte differentiation contributes to MASLD.
    DOI:  https://doi.org/10.1038/s41467-026-73660-6
  2. Nat Genet. 2026 Jun 02.
    VA Million Veteran Program
      Genome-wide association studies have identified >100 loci associated with metabolic dysfunction-associated steatotic liver disease (MASLD), yet the mechanisms by which noncoding variants alter disease risk remain unclear. Here we map chromatin accessibility in human MASLD liver nuclei, revealing enrichment of risk variants within cell-type-specific regulatory elements bound by lineage-determining transcription factors. Using a massively parallel reporter assay, we identified hundreds of differential activity variants (DAVs) that act in a cell-type-dependent and stimulus-dependent manner and perturb transcriptional regulatory networks linked to liver pathology. Integration of liver expression quantitative trait loci, chromatin looping and single-cell CRISPR interference screening assigns target genes to these DAVs. Importantly, DAVs at numerous loci, including SLC22A3 and key triglyceride metabolism regulators (APOA5, ANGPTL3 and LPL), modulate gene expression, lipid metabolism and hepatic stellate cell activation. Moreover, these DAVs allow improved prediction of MASLD risk. These results define a regulatory framework linking noncoding genetic variation to MASLD pathogenesis.
    DOI:  https://doi.org/10.1038/s41588-026-02617-8
  3. Cell Metab. 2026 Jun 02. pii: S1550-4131(26)00152-X. [Epub ahead of print]38(6): 1079-1080
      After decades without approved pharmacotherapies, mitochondrial disease care is shifting. Two FDA approvals emerged in 1 year, elamipretide (Forzinity) for Barth syndrome and deoxynucleoside therapy (Kygevvi) for TK2 deficiency, with another under review. Zink et al.1 suggest sildenafil (Viagra) could treat Leigh syndrome, highlighting drug repurposing for severe pediatric mitochondrial disease.
    DOI:  https://doi.org/10.1016/j.cmet.2026.04.014
  4. Mol Metab. 2026 Jun 01. pii: S2212-8778(26)00073-6. [Epub ahead of print] 102389
      Metabolic liver disease arises due to dysregulated signaling between hepatocytes and non-parenchymal cells (NPCs). Through parallel RNA sequencing screens in diet-induced and genetic mouse models, backdropped by human transcriptomic data, we identified latent TGFβ binding protein-3 (LTBP3) - a regulator of TGFβ secretion - as a novel contributor to metabolic liver disease pathogenesis. GalNAc-conjugated Ltbp3 ASO reduced hepatic triglyceride accumulation in diet-induced metabolic liver disease mouse models, which was phenocopied in mice lacking hepatocyte TGFβ activity, but surprisingly not in hepatocyte-specific Ltbp3 knockout mice. This discordance prompted evaluation as to whether GalNAc-based tools are hepatocyte-specific. In fact, we found that GalNAc-Ltbp3 ASO also targeted multiple NPC populations, reducing intrahepatic TGFβ activity, culminating to lowered lipid content by increased proteasomal degradation of the key lipogenic enzyme Acetyl-CoA-Carboxylase 1 (ACC1) in hepatocytes. These data reveal a previously unrecognized NPC-hepatocyte axis to regulate lipogenesis in metabolic liver disease.
    Keywords:  Lipogenesis; MASH; MASLD; TGFβ
    DOI:  https://doi.org/10.1016/j.molmet.2026.102389
  5. Cell Rep. 2026 Jun 04. pii: S2211-1247(26)00513-9. [Epub ahead of print]45(6): 117435
      5-methylcytosine is a reversible regulatory mark in mammalian genomes whose distribution varies across genetic loci, cell types, and disease conditions. Cytosine-5 methylation is brought about by three AdoMet-dependent DNA methyltransferases (DNMTs) with primary tasks in de novo (DNMT3A and DNMT3B) or maintenance (DNMT1) methylation. However, the precise roles and interplay between the three methylation "writers" remain obscure. To selectively track an individual DNMT, we derived a heterozygous mESC line with chromosomal alleles expressing the wild-type and a sterically engineered variant of DNMT1. This enables catalysis-dependent chemical tagging DNMT1 methylation sites upon in-cell delivery of a synthetic AdoMet analog. Genome-wide mapping of the DNMT1 catalysome during naive-to-primed transition of mESC shows that DNMT1 contributes to de novo methylation of germline genes and competes with active demethylation at boundaries of CpG islands. Altogether, we provide a unique tool for chemical monitoring of individual methylation writers in minimally perturbed developmental and disease models.
    Keywords:  AdoMet cofactor analogs; AdoMet-dependent methyltransferase; CP: genomics; CP: molecular biology; DNA cytosine-5 methylation; Embryonic stem cells; Epigenomic tools; bioorthogonal click labeling; epigenetic reprograming; precision genome editing
    DOI:  https://doi.org/10.1016/j.celrep.2026.117435
  6. Cell Death Dis. 2026 Jun 05.
      Mitochondria undergo fusion and fission. While DRP1 regulates fission, fusion is controlled by OPA1, MFN1, and MFN2. The balance between these processes and the crosstalk between machineries remains poorly understood. MFN2 mutations cause Charcot-Marie-Tooth disease type 2 A (CMT2A), affecting mitochondrial fusion and morphology. However, their role in fission is unclear. Using skin fibroblasts from CMT2A patients (L248H and M376V MFN2 mutations) and wild-type mouse embryonic fibroblasts expressing these variants, we studied how MFN2 mutations impact mitochondrial dynamics beyond fusion. We analyzed mitochondrial morphology and dynamics by live-cell confocal microscopy and tested fusion/fission protein levels, oxygen consumption rate (OCR), extracellular acidification rate (ECAR), and oxidative phosphorylation complex subunits. MFN2 mutations impaired mitochondrial fusion and displayed distinct effects on fission and cellular metabolism. L248H-expressing cells showed hyper-elongated mitochondria, impaired fission, and increased OCR, while M376V cells exhibited fragmentation, enhanced fission, and elevated ECAR. These effects correlated with differential Drp1 phosphorylation. Our findings demonstrate that MFN2 mutants differentially influence fission and metabolism, highlighting the need to consider these effects in therapies aimed at modulating mitochondrial dynamics.
    DOI:  https://doi.org/10.1038/s41419-026-08838-3
  7. Trends Mol Med. 2026 Jun 02. pii: S1471-4914(26)00114-0. [Epub ahead of print]
      
    Keywords:  adipose tissue; insulin resistance; lipodystrophy; whole-body metabolism
    DOI:  https://doi.org/10.1016/j.molmed.2026.05.005
  8. medRxiv. 2026 May 19. pii: 2025.09.24.25336527. [Epub ahead of print]
    Genes & Health Research Team
      Type 2 diabetes (T2D) is a common and complex metabolic condition with significant heterogeneity within and across ancestries 1-4 . Compared with individuals of European ancestry (EUR), people of south Asian ancestry (SAS) have two to four-fold higher risk of T2D, develop the disease at younger ages and lower body mass index (BMI), and experience more rapid progression to complications 5-10 . Understanding the genetic basis of this is hindered by low representation of south Asians in genetic studies. Here, we perform an exome-wide association study of T2D in 13,674 cases and 41,024 controls from the Genes & Health study of British Pakistani and Bangladeshi individuals. We identify a novel rare variant in HNF4A - a canonical monogenic diabetes / MODY gene, in which missense variants would be expected to increase T2D risk. Surprisingly, HNF4A Pro437Ser is associated with a halved risk of T2D and reduced risk of diabetes-related complications but increased non-HDL cholesterol. We additionally characterise a T2D risk-increasing variant which is common only in South and East Asian ancestral groups ( GP2 Val429Met), which is associated with lower BMI and phenotypic and genetic markers of insulin deficiency. We validate our findings through replication in independent multi-ancestry cohorts, in vitro functional assays, and integration of proteogenomic analysis. These findings highlight how the study of under-represented populations can identify biological mechanisms associated with disease phenotypes enriched in those populations.
    DOI:  https://doi.org/10.1101/2025.09.24.25336527
  9. medRxiv. 2026 May 24. pii: 2026.05.21.26353759. [Epub ahead of print]
    Colorado Center for Personalized Medicine
      Rare coding variants can have large effects on disease risk and provide direct routes from human genetics to disease mechanisms and therapeutic targets, but their discovery is constrained by sample size, particularly for low-prevalence diseases. Here we establish the Biobank Rare Variant Analysis (BRaVa) consortium, a global rare variant association resource that integrates sequencing and linked health-record data from ten biobanks and cohorts comprising over 1.2 million individuals across diverse ancestries. We performed gene-based meta-analyses of rare coding variation across 33 clinical endpoints and 11 quantitative traits. Aggregating evidence across biobanks and ancestries identified 514 gene-trait associations, including 31 not previously reported in prior studies or curated association resources following systematic literature review. Notably, 36.1% of gene-level associations were undetectable in any individual biobank, and 91 emerged only through cross-ancestry meta-analysis, demonstrating that federated integration enables discovery beyond the reach of single cohorts. Similar gains were observed at the variant level, where 25.0% of phenotype-locus associations were detectable only through meta-analysis. Effect size estimates were correlated across ancestries with concordant directions of effect, supporting the generalizability of rare variant associations. The identified signals implicate pathways involved in transcriptional and epigenetic regulation, metabolism, vascular and epithelial biology, and immune function, highlighting rare coding variation as an engine for biological discovery across medical record phenotypes. For example, damaging variation in ANKRD12 implicates inflammatory transcriptional dysregulation in asthma and chronic obstructive pulmonary disease, and ultra-rare predicted loss-of-function variants in NAA15 link protein acetylation processes to type 2 diabetes risk. BRaVa establishes a scalable framework and freely available community resource for rare variant meta-analysis across global biobanks. Public release of gene- and variant-level association summary statistics provides a reference map of rare coding variant associations to support disease gene discovery, biological interpretation, and therapeutic target prioritization as sequencing-linked health-record resources continue to expand.
    DOI:  https://doi.org/10.64898/2026.05.21.26353759