Metabolism

Background: Sodium-glucose cotransporter-2 (SGLT2) inhibitors reduce cardiovascular mortality and chronic kidney disease (CKD) progression in cardiovascular-kidney-metabolic (CKM) syndrome, but this benefit derives primarily from reductions in heart failure and cardiovascular mortality rather than in atherothrombotic events. Sotagliflozin, which inhibits both intestinal SGLT1 and renal SGLT2, is the only drug in this class shown to lower rates of myocardial infarction and stroke in CKD. However, its mechanism remains unclear, and its effectiveness in non-diabetic CKD has not been studied. We hypothesized that dual SGLT1/2 inhibition reprograms systemic substrate utilization toward fatty acid oxidation, which may partially account for this protective effect. Methods: CKD was induced in male low-density lipoprotein receptor-deficient mice by 5/6 nephrectomy. Sham and CKD mice received a high-fat diet and drinking water containing sotagliflozin, empagliflozin, or vehicle for 16 weeks, at doses that produced equivalent fractional excretion of glucose. We quantified atherosclerosis en face and in the aortic sinus. Indirect calorimetry, echocardiography, hepatic RNA sequencing, plasma acylcarnitine profiling, and in vivo deuterium labeling of palmitate were performed. Results: At matched levels of glucosuria and plasma total cholesterol, sotagliflozin decreased body mass, atherosclerosis burden, triglycerides, and TNF- more than empagliflozin, and raised postprandial total GLP-1 approximately 3-fold, while both drugs similarly improved albuminuria and diastolic function. Sotagliflozin increased energy expenditure independent of body mass and lowered respiratory exchange ratio despite compensatory hyperphagia. Sotagliflozin reduced hepatic lipogenic genes and de novo lipogenic flux, while increasing {beta}-oxidation and ketogenesis; empagliflozin only activated the oxidative pathway. Conclusions: In experimental CKM syndrome, dual SGLT1/2 inhibition reduces atherosclerosis and metabolic syndrome more effectively than selective SGLT2 inhibition and is associated with reprogramming of hepatic lipid metabolism. These results suggest that sotagliflozin could be an attractive candidate for mitigating atherosclerotic risk in non-diabetic CKD.

Background: Tonic endothelium-derived nitric oxide (NO) suppresses platelet activation physiologically, and its loss underlies the thrombotic risk of endothelial dysfunction. Inorganic nitrate and nitrite provide an alternative NO source, and xanthine oxidoreductase (XOR) is a candidate nitrite reductase, but whether endogenous XOR sustains platelet NO signalling in vivo, and its source is unknown. Methods: Dietary nitrate (15 mmol/L KNO3) was given to eNOS-/- and ApoE-/- mice. XOR was interrogated pharmacologically (allopurinol) and genetically (global Xdh+/- and hepatocyte-specific XOR knockout, HXOR KO). Haemostasis and thrombosis were assessed by tail bleeding and intravital microscopy imaging of FeCl3-induced mesenteric arterial thrombosis, alongside aggregometry, flow cytometry, platelet VASPSer239 phosphorylation, cGMP and ozone chemiluminescence-based analysis of nitrate and nitrite. Results: Dietary nitrate raised plasma nitrate and nitrite levels in all genotypes. In eNOS-/- and ApoE-/- mice, it prolonged bleeding time and normalised thrombus burden. In ApoE-/- mice nitrate treatment improved vasorelaxation, without altering XOR or eNOS expression. Allopurinol suppressed nitrite reductase activity in liver and plasma but not aorta, elevated plasma nitrite, shortened bleeding time and reduced platelet P-VASPSer239 expression. Xdh+/- mice were spontaneously prothrombotic, showed reduced P-VASPSer239 and exaggerated calcium mobilisation, and were refractory to dietary nitrate treatment despite equivalent nitrite elevation. XOR was undetectable in platelets. HXOR KO mice phenocopied global deficiency, with blunted nitrite-induced vasorelaxation but preserved acetylcholine and spermine-NO responses, reduced P-VASPSer239, enhanced aggregation and shortened bleeding time. Conclusions: Hepatic XOR sustains platelet NO-cGMP signalling and thromboresistance through an inter-organ, endocrine-like axis. Dietary nitrate restores antithrombotic protection when endothelial NO generation fails, whereas XOR inhibition removes physiological tonic antithrombotic signal.

Obesity is a chronic disease of disordered energy balance for which durable weight management remains an unmet need. The rise in use of anorectic therapies, such as incretin analogues, now particularly highlights the need for therapies which maintain weight loss after cessation of effective pharmacotherapy. Phosphodiesterase 10A (PDE10A) inhibition increases energy expenditure and promotes white adipose tissue browning in preclinical models, providing a mechanistic rationale for its therapeutic application. Two complementary studies in male diet-induced obese C57BL/6J mice were conducted to evaluate its pharmacological activity. In a 21-day dose-response study, BEN-8744, an orally bioavailable, peripherally-restricted, PDE10A inhibitor, significantly attenuated body weight gain relative to vehicle at all doses tested. In a 40-day weight maintenance study, mice pre-treated with semaglutide were switched to vehicle-only, BEN-8744, the brain-penetrant PDE10A inhibitor mardepodect or continued semaglutide. Mardepodect was comparable to continued semaglutide, significantly suppressing food intake and weight gain. BEN-8744 showed numerically less gain than vehicle but this difference did not reach statistical significance. Contrary to mardepodect treatment, BEN-8744 also did not significantly improve glucose tolerance or serum insulin. These findings establish BEN-8744 as pharmacologically active through a food-intake-independent mechanism consistent with increased energy expenditure, but indicate that its efficacy is modest relative to additional central PDE10A inhibition. Central PDE10A target engagement is essential for a sustained anti-obesity effect.

Background: Type 2 diabetes (T2D) has been associated with reduced abdominal aortic aneurysm (AAA) risk and slower growth in observational studies, but the mechanism for this paradoxical association remains unclear. We hypothesized that T2D's mechanistic heterogeneity obscures opposing, pathway-specific effects on AAA. Methods: We performed two-sample Mendelian Randomization (MR) to investigate the effect of T2D (T2DGGI, 242,283 individuals with T2D and 1,569,730 without) on AAA (AAAgen, 37,214 individuals with AAA and 997,456 without) using 449 genetic instruments. We also performed MR within previously defined clusters representing different mechanisms of T2D. We extended the analysis to individual hyperglycemic, insulin-resistance, and insulin-sensitivity traits. Our hypothesis was tested in a porcine pancreatic elastase murine model of abdominal aortic aneurysm formation. Results: Overall T2D liability showed no net association with AAA liability (OR 1.00, 95% CI 0.96-1.04, P = 0.90), albeit with marked instrument heterogeneity (Cochran's Q = 1356, P = 5 x 10-92) and inconsistency across sensitivity analyses, with a notably protective MR-Egger result (OR 0.87, 95% CI 0.80-0.94, P = 0.0011) and non-zero intercept (P = 2 x 10-4). MR of T2D on AAA within mechanistic clusters showed opposing effects: lipodystrophy (OR 1.47, 95% CI 1.26-1.72) and obesity (OR 1.27, 95% CI 1.18-1.36) cluster membership associated with increased AAA risk, while beta-cell negative proinsulin (OR 0.83, 95% CI 0.76-0.90) and beta-cell positive proinsulin (OR 0.86, 95% CI 0.80-0.93) clusters were protective. This pattern was robust to clustering method. Traits indexing hyperglycemia (fasting glucose, 2-hour glucose, hemoglobin A1c) were associated with reduced AAA risk, while traits indexing insulin resistance (fasting insulin, BMI, waist-hip ratio, triglyceride-to-HDL ratio) were associated with increased AAA risk. In mice, those treated with a high fructose diet as a model for insulin resistance showed increased growth of the abdominal aorta compared with controls, whereas those treated with pancreatoxin streptozotocin as a model for isolated hyperglycemia showed blunted growth. Conclusion: Distinct components of T2D physiology may have differential effects on AAA development. Whereas insulin resistance may promote AAA, hyperglycemia appears to protect against it. Our findings support insulin sensitization as a rational direction for AAA pharmacotherapy and suggest that the pathways mediating the protective effect of hyperglycemia may harbor additional therapeutic targets.

Adult obesity, including morbid obesity, has reached epidemic proportions worldwide. Yet, the current genetic models based on BMI-associated common variants identified through genome-wide association studies (GWAS) explain only a modest fraction of BMI variability. Contribution of rare and low-frequency variants to polygenic obesity remains incompletely defined. Leveraging whole-exome sequences of 1138 adults spanning normal-weight, overweight, obese and morbidly obese (MO) categories from Kuwait and Qatar, we catalogued cohort-specific rare and low-frequency deleterious variants differentiating MO individuals from normal-weight individuals. Cross-cohort comparisons identified 147 risk variants seen in [≥]2 MO individuals from one cohort and in [≥]1 MO individual from the other; among these, 27 variants occurred in [≥]2 MO individuals from each cohort. The risk genes were enriched in obesity-related pathways and tissues, with most harbouring GWAS variants associated primarily with obesity traits followed by metabolic and brain-related traits. Duodenal tissue expression data exhibited significant dysregulation of key risk genes in MO individuals. Variants from the 147-list and 27-list occurred in 87% and 49% of MO individuals, respectively; MO-variant burden correlated positively with BMI (r=0.30 and r=0.31, respectively) across the overweight-obese-MO categories. Combinations of a finite set of low-frequency coding variants substantially shape the continuum of polygenic obesity.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major cause of chronic liver disease, with weight loss as the pivotal therapeutic strategy. However, the metabolic and molecular adaptations underlying rapid weight loss remain incompletely defined. In this pilot study, women with obesity and MASLD but without diabetes consumed a very low-calorie diet (VLCD) for 8 weeks. Clinical parameters, hepatic steatosis measured by controlled attenuation parameter (CAP), circulating metabolites, and microRNAs (miRs) were assessed before and after the dietary intervention. Integrated correlation and hierarchical clustering analyses were performed to identify molecular networks associated with clinical improvement. VLCD was well tolerated, resulting in significant weight loss (~11%) with ~80% adherence. Significant improvements in metabolic parameters were observed, including fat mass, waist circumference, blood pressure, insulinemia, HOMA-IR, HbA1c, and triglycerides, with unchanged liver enzymes. Hepatic steatosis decreased markedly, as indicated by a reduction in CAP, while stiffness remained unchanged. Metabolomic profiling revealed elevated ketone bodies and broad reductions in amino acid levels, consistent with enhanced fatty acid oxidation and a catabolic metabolic state. Correlation analysis identified distinct metabolite signatures associated with hepatic steatosis, with changes in CAP positively associated with changes in amino acids and inversely associated with changes in ketone bodies and tricarboxylic acid cycle intermediates. Circulating miRs underwent selective rather than global remodeling, with only a limited subset showing strong associations with clinical parameters, including CAP and HOMA-IR. Specifically, VLCD altered the circulating levels of miR-148a-3p, miR-140-3p, miR-10b-5p, and miR-345-5p. Integration of metabolomic and miR datasets identified coordinated metabolite-miR modules involving glucose metabolism, branched-chain amino acid catabolism, mitochondrial metabolism, purine metabolism, microbial metabolites, and cellular redox pathways. These findings demonstrate that improvement in hepatic steatosis during VLCD-induced weight loss is accompanied by coordinated remodeling of circulating metabolite-miR networks. Integrated multi-omics analysis identifies candidate molecular signatures associated with metabolic adaptation and highlights circulating miR-metabolite modules as potential biomarkers of therapeutic response in MASLD.

The extracellular matrix (ECM) of adipose tissue regulates metabolic homeostasis, yet how ECM composition drives adipose dysfunction in obesity remains only partially defined. Multi-omics profiling of visceral adipose tissue identified the multidomain ECM protein SVEP1 as a candidate regulator of adipose remodeling; SVEP1 was elevated in obese human adipose tissue and correlated with insulin resistance and systemic inflammation, and interaction analysis predicted associations with ECM proteins, integrins, and cytoskeletal regulators. On a chow diet, Svep1 heterozygous (Svep1+/-) mice gained less weight with lower fasting glucose, and their adipocytes showed enhanced lipolysis and AMPK activation. On a high-fat diet, Svep1+/- mice exhibited attenuated adiposity, improved glucose tolerance and insulin sensitivity, and fewer adipose macrophages with a shift away from a pro-inflammatory profile, alongside downregulation of inflammatory, lipid-metabolic, and ECM-remodeling pathways. Decellularized Svep1+/- matrix altered macrophage adhesion and phenotype relative to Svep1+/+ matrix, identifying SVEP1 as a matrix-borne mediator coupling adipose remodeling to immune activation and metabolic impairment. Together, these findings position the adipose ECM as an active driver of immunometabolic dysfunction and nominate SVEP1 and its receptor network as candidate targets in obesity.

Insulin resistance (IR) is a hallmark feature of Type 2 Diabetes Mellitus and a well-established risk factor for coronary heart disease (CHD), yet the pathways through which IR contributes to CHD remain incompletely understood. To comprehensively describe the genetic architecture of IR, we collected three direct IR indicators--- fasting insulin (N = 151,013), the Modified Stumvoll insulin sensitivity index (N = 53,657), and pro-insulin (N = 45,861), and conducted joint analysis on them using Linkage Disequilibrium (LD) Score Regression and factor analysis. A single latent IR factor was generated which captures 60.5% of the shared genetic variance. Based on the IR factor, a multivariate GWAS was conducted within Genomic Structural Equation Modelling and then we built a polygenic risk score (PRS) of IR for the UK Biobank European cohort (N = 407,767; 55,729 CHD cases and 352,038 controls). Then we performed the association study to quantify the relationship between genetically predicted IR and CHD. Causal mediation analyses were also performed through 2,923 plasma proteins (Olink) and 168 metabolites (Nightingale NMR), followed by serial-mediation models (IR -> protein -> metabolite -> CHD) over all prescreened pairs. Single-mediator screening nominated 938 proteins and 159 metabolites; this yielded 3,669 significant "protein -> metabolite -> CHD" serial-mediation pathways, from which 33 broadly-acting core mediating proteins were prioritized. These acted predominantly through the large and very large high-density lipoprotein (HDL) particle subclasses: 30 of the 33 core proteins and all 14 HDL-subclass metabolites formed 306 pathways, of which 303 (99.0%) amplify the CHD risk. These results map a proteomic and metabolomic axis linking the genetic component of IR to CHD and highlight HDL lipoprotein-subclass biology as a candidate therapeutic and biomarker space.

Mechanical homeostasis plays a central role in promoting and preserving optimal structure and function in the adult aorta. Although pathogenic variants can compromise homeostatic processes, it appears that intramural cells yet attempt to compensate for some genetically induced changes. In particular, lysyl oxidase is higher in the adult Marfan aorta compared with the age-matched control aorta. Here, we block lysyl oxidase in adult Fbn1C1041G/+ Marfan syndrome mice after stimulating aortic disease progression via induced hypertension. Whereas hypertension alone increases aortic dilatation, concurrent blocking of lysyl oxidase results in a dramatic increase in disease severity, driving an otherwise mild aortic phenotype in adult male Fbn1C1041G/+ Marfan mice to aneurysmal dilatations as well as dissection and rupture, with frequent premature death. Deposition and cross-linking of fibrillar collagens, among other extracellular matrix constituents, can represent a protective compensation against severe disease in the Marfan aorta. The present study emphasizes the need clinically to avoid compromising new collagen deposition and suggests that strategies to augment collagen cross-linking could be beneficial.

Arteries are among the first tissues to exhibit age-related dysfunction, yet the metabolic mechanisms driving vascular senescence remain poorly understood. Here, analysis of human aortic transcriptomic data identified HCAR1, encoding the lactate receptor GPR81, as one of the genes most significantly downregulated with age. We therefore investigated whether age-associated loss of GPR81 contributes to cellular senescence within the vessel wall. Senescent human endothelial cells and vascular smooth muscle cells accumulated neutral and oxidized lipids and exhibited increased labile iron and ferroptosis. Silencing GPR81 in early-passage cells recapitulated this metabolic phenotype together with multiple hallmarks of cellular senescence. Moreover, endothelial-specific deletion of GPR81 in young mice was sufficient to induce senescent cell accumulation, impaired lipid homeostasis, endothelial dysfunction, and elastin disorganization. Conversely, pharmacological activation of GPR81 with the agonist CHBA restored fatty acid metabolism, promoted glycolytic reprogramming, and attenuated ferroptotic stress and senescence-associated phenotypes. In lamin A knock-in (LAKI) progeroid mice, CHBA reduced arterial lipid accumulation and cellular senescence, shifted vascular cell composition toward a youthful state, improved endothelial integrity, and restored extracellular matrix homeostasis. Together, these findings identify age-associated loss of GPR81 as a driver of vascular metabolic dysfunction and cellular senescence and establish pharmacological GPR81 activation as a promising therapeutic strategy for preserving vascular homeostasis and mitigating age-associated cardiovascular disease.

Glucagon-like peptide-1 (GLP-1) receptor agonists produce less weight loss in people with type 2 diabetes than without, and higher compensatory doses are limited by gastrointestinal adverse events and lean-mass loss--leaving patients with obesity, type 2 diabetes, and metabolic dysfunction-associated steatohepatitis (MASH) inadequately treated. We tested whether linafexor, a pulsatile farnesoid X receptor (FXR) agonist, could augment the weight-loss efficacy of low-dose semaglutide in this population while preserving tolerability. In this multicenter, randomized, double-blind, placebo-controlled, phase 2 trial, 62 adults with obesity (body-mass index, 30-45 kg/m2), treatment-naive type 2 diabetes, and MASH (MRI-PDFF [≥]10%) were assigned to linafexor (4 mg orally once daily) or placebo, each with semaglutide (0.5 mg once weekly), for 16 weeks. The primary outcome was the percentage change in body weight at week 16. Adding linafexor more than doubled weight loss (-6.17% vs. -2.91%; treatment difference, -3.26%; 95% CI, -5.35 to -1.18; P=0.003), and more participants achieved at least 5% weight loss (53.3% vs. 28.1%; P=0.046). Consistent with this, combination therapy further reduced visceral adipose tissue (treatment difference, -13.85 cm2; P=0.035), the liver enzymes alanine aminotransferase and {gamma}-glutamyl transferase, and serum bile acids, whose changes correlated with weight and liver-enzyme improvements--associations absent with monotherapy. Gastrointestinal adverse events were comparable (23.3% vs. 18.8%), with no treatment-related serious adverse events or discontinuations. Thus, in a population with blunted GLP-1 responses, adding linafexor to low-dose semaglutide enhanced weight loss and improved body composition and hepatic measures while preserving tolerability--a dose-sparing, mechanism-complementary strategy (ClinicalTrials.gov number, NCT06492330).

Background. Type 2 diabetes (T2D) and coronary artery disease (CAD) frequently co-occur, yet the biological pathways that jointly determine risk remain incompletely understood. Most genetic studies have examined shared risk from a single-disease perspective, limiting insight into the mechanisms that generate discordant risk between conditions. Methods. We applied PLACO to multi-ancestry GWAS data of T2D and CAD to identify shared loci, prioritising shared causal signals using colocalisation. Shared variants were clustered by their associations with 77 cardiometabolic traits, and cluster-specific genetic risk scores (GRS) were tested for association with 17 clinical biomarkers and 1,254 binary outcomes in 378,772 UK Biobank (UKB) participants. Two-sample Mendelian randomisation (MR) was used to test the causal role of liver fat. Results. We identified 149 loci shared between T2D and CAD; most novel loci had discordant effects (35 of 42), in contrast to the predominantly concordant signals reported previously. Clustering 187 independent shared variants revealed seven mechanistic clusters, three of them centred on liver fat and defined by discordant T2D?CAD effects. Enrichment analyses and cluster-GRS associations in UKB highlight associations between higher liver fat and T2D risk with a cardioprotective lipid profile and reduced CAD risk. Genetically higher liver fat increased T2D risk but lowered CAD risk in MR analyses; partitioning liver fat instruments by their effect on ApoB-containing lipoproteins indicates that the CAD effects are determined more by effects of circulating ApoB rather than liver fat itself. Conclusions. Liver fat largely sets the direction of T2D risk, whereas the fate of that lipid, retained in the liver with low circulating ApoB or exported as ApoB-containing lipoproteins, sets the direction of CAD risk. This liver-centric partitioning provides a mechanistic framework for the discordant cardiometabolic effects of hepatic lipid and lipid-lowering pathways, with implications for precision prevention.

Plasma proteomic scores for body mass index have been derived primarily in European populations, and it is unclear whether these scores are generalizable and useful in other ancestries. Here, we show that plasma proteomic BMI scores developed in participants of European, East Asian, South Asian and African ancestries from the UK Biobank (UKBB; N=50,621) and the South African Middle-Aged Soweto Cohort (MASC; N=948) are portable across ancestries, explain up to 48.7% of trait variance and significantly predict incident obesity. We identified eight protein biomarkers common across all scores, six of which showed causal associations with BMI in Mendelian randomization analyses and were associated with BMI across the Olink (UKBB, MASC) and SomaScan platforms (Qatar Biobank; N= 2410). Discrepancy analysis between the high predicted proteomic BMI and low measured BMI revealed metabolically unhealthy normal weight (MUNW) individuals, with higher visceral fat, elevated triglycerides, and low insulin sensitivity. Thus, plasma proteomic BMI scores may enhance the precision of cardiometabolic risk stratification across diverse populations

Knockout of the UDP-glucose-activated P2Y14 receptor (P2Y14R) in adipocytes or whole-body has been reported to provide metabolic benefits in obese mice. We hypothesized that selective P2Y14R activation would lead to metabolic impairments, whereas pharmacological antagonism would improve metabolic deficits in diet-induced obese (DIO) mice. Here, we investigated the metabolic effects of a synthetic P2Y14R agonist, UDP-like methylene-bridged MRS2905. Acute P2Y14R activation with MRS2905 triggered a robust and prolonged hyperglycemic effect in lean and obese mice with impaired glucose homeostasis. Moreover, MRS2905 treatment of obese mice lowered fasting plasma insulin and increased glucagon levels, along with upregulation of liver JNK phosphorylation and the expression of rate-limiting gluconeogenic genes. The MRS2905-induced hyperglycemic effect was blunted in whole-body P2Y14R knockout mice compared with wild-type control. In contrast, a potent P2Y14R antagonist mono-ester prodrug (MRS4779) partially reversed the agonist-induced hyperglycemia and restored proper glucose homeostasis after acute treatment. Chronic MRS4779 administration in DIO mice reduced fat mass and improved various metabolic parameters including liver steatosis. Additionally, we examined the roles of P2Y14R in hepatocytes of DIO mice. Here, we report that P2Y14R was upregulated in liver and hepatocytes from obese mice compared to lean mice. Overnight fasting also upregulated hepatic P2Y14R expression. P2Y14R deletion from hepatocytes in DIO mice improved fasting blood glucose level and lipid metabolism without improving glucose homeostasis. These results suggest a novel P2Y14R function in hepatic lipid metabolism, and P2Y14R antagonists may prove useful for the treatment of obesity and obesity-related metabolic disorders.

Obesity is a significant public health concern. Early-onset obesity in the context of rare disease can reflect genetically-mediated pathology or elevated susceptibility through indirect mechanisms. Mapping the diverse characteristics and needs of young people with obesity in the rare disease population is a first step toward mechanistic and translational research. We carried out a retrospective comparative analysis of demographic, genotypic, phenotypic and health service utilisation data for young people with obesity (cases: n=500) and without obesity (controls: n=11,444) from the UK 100,000 Genomes Project rare disease cohort. Cases and controls were recruited prior to genomic diagnosis, across clinical disorder categories. We observed significant association between socioeconomic deprivation and obesity risk. Young people with obesity had significantly higher utilisations of acute care and mental health services, indicating an overall higher health burden. A curated panel of 519 candidate obesity-associated genes demonstrated aggregate association with obesity, although no single gene reached significance. Phenotypic comparison between cases and controls highlighted increased multi-organ and neurological system involvement, highlighting the overlap between neurodevelopmental and obesity risks. Within the case group, we conducted cluster analysis to identify early-onset obesity groups with different phenotypic profiles, potentially arising from different causal pathways - this identified six obesity subgroups of interest, with differing involvement of neurodevelopmental and other systems. Our study confirms that obesity co-occurs with a wide range of factors within the rare disease population, and is associated with significant physical and mental health needs, requiring holistic lifelong care.

BACKGROUNDLysine methyltransferase SET7 activates gene expression through mono- methylation of histone H3 at lysine 4 (H3K4me1) and modulates protein function via mono- methylation of non-histone proteins (Kme1). However, its role and molecular targets in endothelial dysfunction associated with cardiometabolic disorders remain unknown. METHODSEndothelial-specific Setd7 knockout (Setd7EC-KO) mice were generated and endothelial function assessed in WT and Setd7EC-KO mice after high-fat diet (HFD). Human aortic endothelial cells (HAECs) were used to investigate SET7 expression and function under metabolic stress. SET7-dependent histone and non-histone targets were identified by proteomic and ChIP analyses. Insights from these datasets guided the design of bioinformatic, molecular, and functional studies to define their regulatory mechanisms. Clinical relevance was evaluated in human arteries. RESULTSHFD selectively increased endothelial SET7 expression in WT mouse aortas. Despite comparable metabolic abnormalities, Setd7EC-KO mice were protected from HFD- induced endothelial dysfunction, oxidative stress, and inflammation. In HAECs, high glucose emerged as the strongest inducer of SET7 expression, promoting pro-inflammatory and pro- oxidant gene expression, monocyte adhesion, and ROS generation. These effects were reproduced by overexpression of catalytically active SET7 and reversed by its inhibition or silencing. Proteomic and ChIP analyses revealed that SET7-dependent H3K4me1 activates transcription of spliceosome components, linking aberrant mRNA splicing to endothelial inflammation and oxidative stress. Moreover, Kme1-proteomics identified endothelial nitric oxide synthase (eNOS) as a direct SET7 substrate. Bioinformatic analyses and mutagenesis experiments demonstrated that SET7-mediated mono-methylation of eNOS at K494 disrupts calmodulin (CaM) binding and impairs NO synthesis. These molecular signatures were also observed in internal mammary arteries from patients with vascular disease and hyperglycemia. CONCLUSIONSSET7 drives endothelial dysfunction through a dual mechanism: 1) H3K4me1-dependent activation of splicing machinery triggering inflammation and oxidative stress, and 2) eNOS mono-methylation at K494 reducing NO bioavailability. Targeting SET7 may therefore represent a promising avenue to safeguard endothelial homeostasis in cardiometabolic disease. GRAPHIC ABSTRACTA graphic abstract is available for this article.

The GLP-1-based obesity drug semaglutide lowers bodyweight primarily by increasing satiation and satiety, whilst also reducing food reward and commonly causing nausea. The brainstem dorsal vagal complex (DVC) has been identified as a key site of action for these phenotypic components of semaglutides anorectic effect. However, which GLP-1 receptor (GLP-1R) populations within the DVC are recruited to mediate these phenotypic components, and whether they are dissociable, are translationally important but unresolved questions. We addressed these using metabolic and behavioural phenotyping, combined with activity-dependent genetic labelling ( Sema-TRAP) and chemogenetic manipulation of semaglutide-recruited brainstem circuits. Semaglutide potentiated satiation and satiety, caused behavioural proxies of nausea, and suppressed motivation for Western diet, in a largely sex-independent manner. It activated a substantial proportion of GLP-1R-expressing neurons in the brainstem area postrema (AP), but surprisingly most semaglutide-activated neurons in the nucleus tractus solitarius (NTS) did not express GLP-1R. Chemogenetic reactivation of Sema-TRAP neurons in the NTS alone was sufficient to recapitulate the acute effects of semaglutide on satiation, nausea, food reward, and bodyweight. Knockdown of GLP-1R expression in the AP before Sema-TRAPing abolished the recruitment of Sema-TRAPNTS neurons which elicited all these effects, while leaving the effects of semaglutide on satiety and bodyweight intact. These data demonstrate that semaglutide recruits dissociable anorectic circuits to suppress eating via distinct behavioural mechanisms, with non-GLP-1R NTS neurons downstream of GLP-1RAP representing potential therapeutic targets to tune GLP-1-based obesity drugs towards a better-tolerated effect profile.

Background & Aims: Childhood obesity is a complex, heterogeneous disease. Children with obesity are often grouped into metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) phenotypes, although this classification may oversimplify the underlying metabolic diversity. We aimed to characterise the metabolic profiles associated with the conventional MHO/MUO classification and to identify data-driven metabolic profiles in 267 children and adolescents with obesity. Methods: In this cross-sectional study, we used serum 1H-NMR spectroscopy to quantify lipoproteins, glycoproteins, low-molecular-weight metabolites, and lipid fractions. Univariate comparisons and partial least squares discriminant analysis (PLS-DA) were used to characterise NMR-derived variables associated with MHO and MUO groups. We applied unsupervised k-means clustering based on principal component scores to identify data-driven metabolic profiles independent of the predefined clinical phenotypes. Results: Forty-one NMR-derived variables differed between MUO and MHO (FDR q-value < 0.05), predominantly in the triglyceride-rich lipoprotein and glycoprotein profiles, of which 31 were elevated in MUO. PLS-DA discriminated between MHO and MUO (AUC = 0.84, Q2 = 0.33; permutation p < 0.001). Unsupervised clustering identified two data-driven metabotypes that only partially overlapped with the clinical phenotypes: 27% of children with MHO clustered within the adverse metabolic profile (Cluster 2), characterised by a triglyceride-rich and inflammation-associated profile, whereas 41% of children with MUO were assigned to the comparatively favourable profile (Cluster 1). Clustering further revealed additional differences in lipoprotein subclasses and lipid composition that the MHO/MUO classification did not capture. Conclusions: The conventional MHO/MUO classification captures an important component of metabolic variation in childhood obesity but does not fully capture cardiometabolic heterogeneity. Quantitative 1H-NMR metabolomics identified putative metabotypes characterised by differences in lipoprotein composition and cholesterol distribution beyond clinical phenotypes. These findings support the potential value of metabolomic profiling to refine cardiometabolic risk stratification in children with obesity; however, the relevance of these data-driven metabotypes requires confirmation in independent cohorts and longitudinal follow-up studies.

Obesity is a global epidemic characterized by metabolic dysfunction, with white adipose tissue playing a pivotal role in these processes. Noncoding RNAs, such as long non-coding RNAs (lncRNAs) and short non-coding RNAs (e.g., microRNAs), have been identified as an emerging class of regulatory molecules that can influence metabolic function. Here, the Dleu2/miR-15a/16-1 cluster (known as 13q14-Minimal Deleted Region, i.e., MDR), which encodes the lncRNA Dleu2 and miR-15a/16-1, a previously unrecognized player in metabolic function, is shown to contribute to obesity and insulin resistance. Using a combination of phenotypic and molecular approaches, this study establishes that MDR governs metabolic regulation for the first time. In a nutshell, this study identifies a new role of a lncRNA-miRNA cluster, previously implicated exclusively in cancer, in the regulation of obesity, thereby extending its biological significance beyond oncology. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=184 SRC="FIGDIR/small/745519v1_ufig1.gif" ALT="Figure 1"> View larger version (68K): org.highwire.dtl.DTLVardef@424a1borg.highwire.dtl.DTLVardef@f6e3eorg.highwire.dtl.DTLVardef@10ebf0borg.highwire.dtl.DTLVardef@120803c_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIDeletion of MDR contributes to obesity, insulin resistance, and impaired energy metabolism C_LIO_LILoss of MDR reduces circulating adiponectin levels, indicating metabolic dysfunction C_LIO_LIMDR regulates satiety signaling in visceral adipose tissue and increases serum leptin levels C_LIO_LIMDR modulates several unrecognized new transcriptional regulators in obesity C_LIO_LIFirst evidence to establish the metabolic role of MDR beyond cancer biology C_LI

Diabetes and obesity increase cardiac lipid levels leading to cardiomyopathy and heart failure. We hypothesized that intermittent fasting would reduce cardiac lipid levels. Surprisingly, intermittent fasting increased myocardial triglyceride content, but rescued mortality and attenuated cardiomyopathy in mice overexpressing cardiomyocyte acyl-CoA synthetase 1 (MHC-ACSL1). Lipid overload caused cardiomyocyte accumulation of polyubiquitinated protein aggregates containing desmin, a scaffolding intermediate filament protein, which intermittent fasting prevented. Furthermore, intermittent fasting reversed elevated myocardial C16:0 ceramide content, and knockdown of ceramide synthase CerS5 and CerS6 reduced palmitate-induced protein aggregation, highlighting a role for C16:0 ceramides in this pathology. Conversely, impairing aggrephagy with cardiomyocyte-specific p62 ablation induced heart failure in mice fed a high-fat diet, with paradoxically reduced cardiac lipid content. Crucially, non-failing diabetic human hearts also exhibited protein aggregate pathology. Taken together, these results demonstrate that impaired proteostasis characterizes cardiomyopathy from cardiac lipid overload and identify a promising new therapeutic target for this condition.