Metabolism

BackgroundObesity is a serious risk factor for cardiovascular diseases. A high fat diet results in cellular oxidative stress and endothelial dysfunction in resistance-sized arteries, characterized by reduced nitric oxide (NO) and endothelium-dependent hyperpolarizing (EDH) responses. Thioredoxin-1, a sulfo-oxidoreductase protein that cleaves disulfide bridges between two adjacent cysteine residues in oxidized proteins, has been shown to lower blood pressure and improve endothelium-dependent relaxing responses in aged C57Bl6/J mice.\n\nMethods and ResultsYoung ([~] 3 month-old) male C57Bl6/J mice were fed a high fat diet (42% kcal from fat; obese) or a normal chow (lean) for 3 months. Mice were administered recombinant human thioredoxin-1 (rhTrx; 25 mg/kg) or saline (0.9% NaCl) via tail vein injection at the start, after one month, and after two months. Body weight (BW) was comparable between lean/rhTrx1 and lean/saline at the time of euthanasia (32 {+/-}1 g versus 32 {+/-} 1 g). The high fat regimen resulted in a comparable BW between obese/saline and obese/rhTrx mice (47 {+/-} 1 g versus 45 {+/-} 2 g, respectively). Small (second-order branches) mesenteric arteries (MA2), coronary and femoral arteries were isolated and mounted on the wire-myograph. MA2 and femoral arteries from obese/saline had blunted acetylcholine (10-9 - 10-5 M)-mediated relaxations compared to lean/saline mice, but not to the NO donor sodium nitroprusside. NO and EDH-mediated relaxing responses were blunted in MA2 from obese/lean mice compared to the three other groups.\n\nConclusionTail vein injections with rhTrx prevented endothelial dysfunction in obese mice by improving NO and EDH relaxing responses in MA2.

High-fat, high-sucrose (HFHS) diets are established risk factors for obesity. In the intestine, sucrose is hydrolyzed into glucose and fructose, with fructose being taken up by epithelial cells and phosphorylated by ketohexokinase (KHK). We hypothesized that KHK is required for the obesogenic effects of HFHS diets and performed genetic and pharmacologic experiments in mice using diet-induced obesity (DIO) models. We show that genetic loss of KHK prevents HFHS-induced weight gain and intestinal villus elongation. Moreover, pharmacologic inhibition of KHK (KHKi) promotes weight and fat loss during continued HFHS feeding in DIO mice and enhances weight loss and weight maintenance during and after incretin-mimetic therapy. The anti-obesogenic effects of KHKi were associated with delayed intestinal lipid absorption, reprogramming of lipid metabolism in the distal intestinal epithelium, and reduced absorption of unsaturated dietary fats. Together, these findings identify fructose metabolism as a key regulator of intestinal lipid handling and suggest that fructose promotes obesity, in part, by enhancing intestinal lipid absorption and metabolism.

NAD+ deficiency underlies obesity-induced metabolic disturbances. Here we evaluated the treatment effect of a new and potent NAD+ enhancer, dihydronicotinamide riboside (NRH), in diet-induced obese mice with hyperglycemia and hyperlipidemia. Administering NRH for 7 weeks improved glucose homeostasis by enhancing pancreatic beta-cell functional mass, increasing muscle insulin sensitivity, and reducing hepatic gluconeogenesis. NRH treatment also mobilized fat deposition, reduced circulating lipid, and improved white adipose function. Significant elevation in multi-tissue NAD+ levels and sirtuin (SIRT) activities, especially SIRT3, mediated these metabolic improvements. Inhibiting adenosine kinase (ADK), a newly recognized enzyme in the NRH-induced NAD+ synthesis pathway, blocked NRHs effect in improving glucose and lipid metabolism. ADK inhibition also reduced tissue NAD+ elevation and the subsequent activation of SIRT3, suggesting an active ADK pathway is necessary for NRH-induced metabolic benefits. These observations, for the first time, establish NRH as a promising intervention for correcting obesity-induced metabolic syndrome.

We conducted a comprehensive genetic investigation of obesity in a cohort of 93,673 Korean individuals, categorized by both body mass index and waist circumference using Korean-specific and international criteria. To explore the genetic architecture of obesity and its comorbidities, we performed genome-wide association studies and constructed polygenic risk scores (PRSs) using both conventional single trait and advanced multiple-trait models, including the PRSsum approach. Our analyses identified genome-wide significant loci and demonstrated higher heritability for general obesity than abdominal obesity, and for moderate compared to severe obesity. Notably, East Asian populations showed stronger genetic correlations between abdominal obesity and obesity-related diseases. Both single trait and multiple trait PRSs stratified individuals by risk, with low PRS individuals exhibiting reduced risk for obesity, hypertension, and type 2 diabetes, while high PRS individuals displayed elevated risk, particularly under the multiple trait model. Additionally, interaction and mediation analyses revealed distinct genetic pathways through which obesity contributes to disease development. Collectively, our findings uncover key loci and shared genetic mechanisms linking obesity and its comorbidities in the Korean population. These insights highlight the value of multiple trait PRS models and underscore the importance of ancestry-specific genetic research for addressing the obesity epidemic.

ObjectiveThis research aims to uncover the factors associated with circulating FGF21 levels in a cohort mimicking metabolic disease progression, examining its relationship with adipose tissue (AT) morphology and function. It also investigates FGF21 level changes post-metabolic surgery, predictive factors, and their links to metabolic adjustments. DesignIn this observational study, serum FGF21 was measured in 678 individuals cross-sectionally and longitudinally in 189 undergoing metabolic surgery. We explored links between FGF21, AT histology, cardiometabolic risk factors, weight loss, glucose metabolism changes using feature selection algorithms, univariate/multivariate models, and transcriptome/proteome network analyses in subcutaneous and visceral AT. ResultsFGF21 levels track closely with central adiposity, subclinical inflammation, insulin resistance, and cardiometabolic risk, with circulating leptin emerging as the top predictor. Visceral AT inflammation was associated with liver dysfunction and FGF21 elevation. Post-surgery, FGF21 peaked transitorily at 3 months and predicted fat mass loss at 12 months but not HOMA-IR improvements. Mediation analysis indicated an increased catabolic and AT-lipolytic state associated with higher liver enzyme and FGF21 levels (total effect 0.38, p<0.01; proportion mediation 32%, p<0.01). AT fibrosis was related to a blunted transitory FGF21 increase, and lower fat loss, and hence linked with a reduced surgical effect (FFA and visceral AT fibrosis: rho=-0.31, p=0.030; FFA and fat-mass loss: rho=0.17, p=0.020). ConclusionFGF21 reflects the livers metabolic response to AT characteristics in both central adiposity and after metabolic surgery, with its dynamics reflecting AT-liver crosstalk.

ObjectiveMaternal obesity is usually associated with placental hypovascularity. This study aimed to challenge this paradigm by investigating the immediate vascular adaptations in the placental labyrinth zone in response to short-term, diet-induced obesity. The study hypothesised that there would be an initial compensatory hypervascularisation before the onset of systemic metabolic disease. MethodsFemale Wistar rats were fed either a standard control diet (CG, n = 9) or an ultra-processed, hypercaloric cafeteria diet (EG, n = 9) for eight weeks to induce obesity. On gestational day 16.5, maternal morphometric and biochemical analyses were performed alongside detailed placental histomorphometry and immunohistochemistry for CD31/-actin, in order to quantify foetal vessel density in the labyrinth zone using ImageJ. ResultsThe cafeteria diet successfully induced a significant obese phenotype (mean weight gain: 62.73 g in the experimental group (EG) versus 32.26 g in the control group (CG); P < 0.0001), but did not induce significant hyperglycaemia or dyslipidaemia (P > 0.05). Although there were no significant differences in foetal or placental weights, the labyrinth zone of the EG showed a significant increase in foetal vessel density (29.08 {+/-} 1.91 vessels/field) compared to the CG (26.06 {+/-} 1.80 vessels/field; P = 0.014), indicating robust vascular remodelling. ConclusionShort-term exposure to an obesogenic diet triggers significant compensatory hypervascularisation in the placenta of rats, which is an adaptive response that precedes systemic metabolic dysfunction. This finding contrasts with the hypovascularity observed in chronic obesity. The discrepancy between increased vascular density and foetal growth underscores the importance of evaluating not only the quantity but also the quality and function of blood vessels when assessing placental health in cases of maternal obesity. HighlightsO_LIAcute cafeteria diet-induced obesity causes placental hypervascularity. C_LIO_LIIncreased placental vasculature does not correlate with enhanced foetal growth. C_LIO_LIRapid obesity develops without major pre-gestational metabolic disruption. C_LIO_LIA biphasic model of vascular adaptation to maternal obesity is proposed. C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=112 SRC="FIGDIR/small/664837v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@1090dfaorg.highwire.dtl.DTLVardef@174c7cdorg.highwire.dtl.DTLVardef@1e9a413org.highwire.dtl.DTLVardef@131bf9_HPS_FORMAT_FIGEXP M_FIG C_FIG

BackgroundMetabolically healthy obesity (MHO) is unstable, with up to 80% of individuals progressing to metabolically abnormal obesity (MAO), yet mechanisms underlying this transition remain unclear. African Americans bear a disproportionate burden of obesity-related cardiovascular disease. Circulating extracellular vesicles (EVs) mediate inter-organ communication and may drive MAO-related vascular dysfunction. MethodsAdults of African ancestry were classified as metabolically healthy lean (MHL, n=14), MHO (n=9), or MAO (n=16). Plasma-derived EVs were characterized and their microRNA cargo profiled. Human coronary artery endothelial cells were treated with EVs from each group to assess nitric oxide signaling, oxidative stress, inflammatory activation, and mitochondrial dynamics. ResultsMHO participants exhibited preserved insulin sensitivity and lower inflammation compared with MAO despite comparable adiposity. EVs from MHO carried a distinct microRNA signature enriched in miR-148a-5p, miR-181c-5p, and miR-1255a, linked to antioxidant and matrix regulatory pathways. MAO EVs were enriched in miR-3613-3p, miR-6842-3p, and miR-326, targeting inflammation and insulin resistance pathways. Compared with both MHL and MHO EVs, MAO EVs suppressed endothelial nitric oxide synthase phosphorylation and reduced nitric oxide bioavailability, with increased reactive oxygen species and ICAM-1 expression. MHO EVs induced an intermediate phenotype with disrupted mitochondrial morphology, supporting a graded continuum of endothelial stress. ConclusionsMHO represents a biologically active intermediate state. Circulating EVs from MHO individuals convey molecular signals that impair endothelial and mitochondrial function, predisposing to vascular injury and progression toward MAO. EV-associated microRNAs are mechanistic mediators and candidate biomarkers of metabolic and vascular deterioration in obesity. CLINICAL PERSPECTIVEO_ST_ABSWhat Is New?C_ST_ABSO_LIThis study systematically investigated extracellular vesicles derived from metabolically healthy obese individuals to define direct vesicle effects on endothelial function using integrated omics coupled to functional outputs. C_LIO_LIExtracellular vesicles from metabolically healthy obesity convey a distinct molecular and biological signature that distinguishes lean and metabolically abnormal obesity. C_LIO_LIMetabolic health status, rather than obesity alone, drives extracellular vesicle-mediated endothelial nitric oxide signaling, oxidative stress, inflammation, and mitochondrial dynamics. C_LI What Are the Clinical Implications?O_LIThese findings explain why some individuals with obesity exhibit preserved vascular function while others develop early endothelial dysfunction. C_LIO_LIStratifying obesity by metabolic health status improves cardiovascular risk assessment beyond body mass index alone. C_LIO_LITargeting extracellular vesicle signaling pathways represents a novel strategy to prevent metabolically healthy individuals from progressing to metabolically abnormal obesity. C_LI

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with poor outcomes. Obesity is a risk factor for several cancers including PDAC due to metabolic dysregulation and inflammation. The ketogenic diet (KD) can alter metabolism and has been evaluated for its effects on tumor progression in non-obese but not obese PDAC using genetically engineered mouse models (GEMMs). We hypothesized that ketone bodies and a KD alter cell and tumor metabolism. We show that ketone treatments altered pyrimidine metabolism in PDAC cells. Moreover, in an obese PDAC GEMM, KD prevented tumor progression independent of weight loss but promoted PDAC in a non-obese PDAC GEMM. The KD-specific delay of obesity-associated PDAC was associated with pancreatic metabolic shifts in pyrimidine, cysteine and methionine, and arginine and proline pathways. These findings suggest potential benefits of a KD in preventing obesity-associated PDAC, but highlights some risks in non-obese settings.

Glucokinase activators (GKAs) have been developed as blood glucose lowering drugs for type 2 diabetes. Despite good short-term efficacy, several GKAs showed a decline in efficacy chronically during clinical trials. The underlying mechanisms remain incompletely understood. We tested the hypothesis that deficiency in the liver glucokinase regulatory protein (GKRP) as occurs with common human GCKR variants affects chronic GKA efficacy. We used a Gckr-P446L mouse model for the GCKR exonic rs1260326 (P446L) variant and the Gckr-del/wt mouse to model transcriptional deficiency to test for chronic efficacy of the GKA, AZD1656 in GKRP-deficient states. In the Gckr-P446L mouse, the blood glucose lowering efficacy of AZD1656 (3 mg/kg body wt) after 2 weeks was independent of genotype. However after 19 weeks, efficacy was maintained in wild-type but declined in the LL genotype, in conjunction with raised hepatic glucokinase activity and without raised liver lipids. Sustained blood glucose lowering efficacy in wild-type mice was associated with qualitatively similar but more modest changes in the liver transcriptome compared with the P446L genotype, consistent with GKA therapy representing a more modest glucokinase excess than the P446L genotype. Chronic treatment with AZD1656 in the Gckr-del/wt mouse was associated with raised liver triglyceride and hepatocyte microvesicular steatosis. The results show that in mouse models of liver GKRP deficiency in conjunction with functional liver glucokinase excess as occurs in association with common human GCKR variants, GKRP-deficiency predisposes to declining efficacy of the GKA in lowering blood glucose and to GKA induced elevation in liver lipids.

Gastric bypass surgery results in long-term weight loss due to re-routing of the gastro-intestinal anatomy and dietary intake alterations. Studies have examined protein change during rapid weight loss (up to 1 year post-surgery), but whether protein changes are maintained long-term after weight stabilization is unknown. To identify proteins and pathways involved with the long-term beneficial effects of weight loss, abundances of 1297 blood-circulating proteins were measured at baseline, 2 and 12 years after Roux-en-Y gastric bypass surgery. Protein changes were compared between 234 surgery and 144 non-surgery subjects with severe obesity, with discovery and replication subgroups. Seventy-one protein changes were associated with 12-year BMI changes and 58 (7 unique) with surgical status. Protein changes, including ApoM, were most strongly associated with long-term changes in lipids (HDL-C and triglycerides). Inflammation, adipogenesis, cellular signaling, and complement pathways were implicated. Short-term improvements in protein levels were maintained long-term, even after some weight regain.

Emerging evidence that circulating levels of key metabolic intermediates are sensed by a range of G-Protein Coupled receptors (GPCRs) is providing critical new insights into the control of systemic metabolic homeostasis, and how disturbances in such sensing may contribute to metabolic disease. The hydroxycarboxylic acid receptors for lactate (HCAR1), {beta}-hydroxybutyrate (HCAR2), and octanoate (HCAR3) are encoded by three closely homologous GPCR genes co-located in a region where common genetic variation has been reportedly associated with lipid levels and body fat distribution. By resolving sequence homology in this region, we were able to refine this signal to a coding variant (R311C) in HCAR2. Using corrected genotypes from [~]500K participants from UK Biobank and direct genotyping of four other studies, we found that carriage of the HCAR2 p.R311C variant was significantly associated with type 2 diabetes risk, reduced gynoid fat mass, increased waist-hip ratio, higher circulating triglycerides, glucose and alanine aminotransferase levels, lower levels of HDL cholesterol and adiponectin and impaired suppression of circulating levels of non-esterified fatty acids after oral glucose. Adipose tissue explants from mice engineered to express the equivalent mutation variant (p.R308C) in the mouse ortholog showed increased lipolytic activity, basally and after {beta}-hydroxybutyrate (BHB) treatment. In vivo, the mice were insulin resistant and had increased liver fat and impaired post-prandial suppression of NEFAs. The variant alters an amino acid located in the intracellular C-terminal tail of HCAR2, increasing recruitment of {beta}-arrestin and resulting in enhanced internalisation and reduced cell surface expression. In conclusion, a common variant in the human ketone body receptor results in impaired control of adipocyte lipolysis and adversely impacts systemic lipid and glucose metabolism. These findings highlight the importance of anti-lipolytic ketone body signalling in adipocytes for the maintenance of metabolic health Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=182 HEIGHT=200 SRC="FIGDIR/small/25336995v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@1dd7e54org.highwire.dtl.DTLVardef@90ca10org.highwire.dtl.DTLVardef@1c1ef16org.highwire.dtl.DTLVardef@137c18b_HPS_FORMAT_FIGEXP M_FIG C_FIG

Consumption of high fat diet (HFD) is linked to reduced cardiac vagal motor output, a main contributor to progression of cardiovascular disease. HFD for 15 days increases extrasynaptic or tonic gamma aminobutyric acid (GABA) current in cardiac projecting neurons in the dorsal motor nucleus of the vagus (CVNDMV), which contributes to dampening cardiac parasympathetic output. However, the mechanism underlying this increased inhibition is unknown. Here, we hypothesize that increased activity of protein kinase C {delta} isoform (PKC{delta}) enhances tonic GABA current in CVNDMV after HFD. Whole-cell patch-clamp recording of retrogradely labeled CVNDMV demonstrated that pan inhibition of PKC activity with GFX, and isoform specific inhibition of PKC{delta} with rottlerin normalize 15-day HFD-induced increases in tonic GABA current, suggesting that PKC{delta} mediates enhanced tonic inhibition. This effect persisted in the presence of dynasore, a clathrin-mediated endocytosis blocker, indicating that the normalization effect of PKC{delta} inhibition on tonic current in HFD is likely independent of clathrin-mediated endocytosis. Furthermore, no differences in PKC{delta} mRNA or protein expression were observed between NFD and HFD, suggesting a post-translational mechanism underpinning increased tonic GABA current after 15 days of HFD. Altogether, this study provides evidence that HFD-induces increased PKC{delta} activity, but not expression, leading to increased tonic GABAergic inhibition in CVNDMV. This increase PKC{delta} activity could explain the cardiac vagal motor output dampening in CVD and be developed into treatments targeting PKC{delta} for CVD.

The intermittent energy restriction (iER) represents an effective dietary strategy for improving metabolic diseases including metabolic dysfunction-associated steatotic liver disease (MASLD) and type 2 diabetes mellitus (T2DM), yet the underlying mechanisms remain elusive. In this study, we integrated human clinical data, mouse models, and in vitro experiments to investigate the role of iER in modulating the gut-liver axis in comorbid MASLD and T2DM. We demonstrate that an iER diet improves hyperglycemia, hepatic steatosis and decreases the abundance of gut pathogen Klebsiella pneumoniae, which is strongly associated with reductions in blood endotoxin, lipopolysaccharide (LPS) levels, suggesting a potential role of K. pneumoniae-derived LPS in mediating effects of the iER on hepatometabolic improvements. We confirm that K. pneumoniae-derived LPS exacerbates lipid accumulation and inflammation using an in vitro model. Mechanistically, we reveal a core target of protein lysine acetylation (Kac), hydroxyacyl-CoA dehydrogenase -subunit (HADHA) Lys353 in the liver of db/db mice through a multi-omics analysis. The iER decreases HADHA-K353 acetylation and enhances its enzyme activity. A Kac-mimicking mutation (K353R) increases its enzyme activity and stability, blocks its binding to the inflammasome adaptor ASC, and alleviates lipid accumulation and inflammation in K. pneumoniae-derived LPS induced in vitro model. This study provides novel insights into the potential benefits of the iER in comorbid MASLD and T2DM.

BackgroundEndothelial dysfunction, dyslipidemia, and myocardial injury are major contributors to cardiovascular disease. Avocado (Persea americana), rich in monounsaturated fatty acids and phytochemicals, has shown lipid-lowering and anti-inflammatory properties, but its integrated effects on vascular injury remain unclear. MethodsMale rats were randomized into six groups (n = 4 per group): control, avocado, L-NAME, L-NAME+drugs (metoprolol+losartan), L-NAME+avocado, and L-NAME+drugs+avocado. Morphometric indices, lipid profiles, cardiac injury enzymes, and vascular biomarkers were measured after treatment. One-way ANOVA with Tukey test assessed group differences, while contour plots and correlation networks visualized biomarker interactions. ResultsL-NAME treatment induced a pathological phenotype characterized by reduced feed efficiency (-40%), weight gain (-80%), and BMI (-18%), together with dyslipidemia (LDL +120%, TG +55%, TC +42%, HDL -28%), myocardial stress (troponin +70%, CK +50%, LDH +35%), and vascular activation (endothelin +350%, VCAM-1 +55%, AngII +80%; all p < 0.01). Avocado supplementation mitigated these effects: BMI and feed efficiency returned to near-control levels, LDL, TG, and TC fell by 30-45%, and troponin, CK, and LDH decreased by [~]25-30%. Endothelin, VCAM-1, and AngII were reduced by 40-55% relative to L-NAME. Network analysis revealed dense pathological correlations under L-NAME (density 0.42), simplified under avocado (0.17), and most normalized with avocado+drugs (0.09), indicating restoration of physiological biomarker independence. ConclusionAvocado supplementation attenuates L-NAME-induced vascular injury by improving metabolic efficiency, correcting dyslipidemia, reducing cardiac injury, and dampening endothelial activation, while reprogramming pathological biomarker networks toward control-like organization HighlightsO_LIAvocado supplementation improves lipid balance, cardiac integrity, and vascular function in L-NAME-induced injury. C_LIO_LIContour and network analyses reveal avocado disrupts maladaptive biomarker couplings and restores control-like organization. C_LIO_LIPreclinical evidence supports avocado as a nutraceutical adjunct for integrated cardiometabolic protection. C_LI GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=152 SRC="FIGDIR/small/681762v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@12bc02borg.highwire.dtl.DTLVardef@1558740org.highwire.dtl.DTLVardef@229d49org.highwire.dtl.DTLVardef@843627_HPS_FORMAT_FIGEXP M_FIG C_FIG

Hypertension drives heterogeneous aortic remodeling, but the mechanisms underlying regional disparities remain unclear. Here, we demonstrate that adaptive immunity orchestrates spatial differences in vascular dysfunction by modulating perivascular adipose tissue (PVAT) phenotype and immune-metabolic crosstalk. Using angiotensin II (AngII)-infused wild-type (WT) and Rag1-/-mice lacking T and B cells, we integrated biaxial mechanical testing, bulk transcriptomics, and PVAT analyses. In WT mice, AngII induced pronounced descending thoracic aorta (DTA) remodeling, marked by wall thickening, reduced circumferential stiffness and inflammatory gene upregulation (Il6, Ccl2). These changes were attenuated in Rag1-/- mice, implicating T cells in thoracic maladaptation. Conversely, the infrarenal abdominal aorta (IAA) exhibited hypertensive resilience in WT mice but unmasked PPAR{gamma}-associated metabolic reprogramming (Pparg, Adipoq) in Rag1-/- mice, suggesting T cells suppress protective abdominal adaptations. PVAT heterogeneity emerged as a key regulator wherein thoracic PVAT (T-PVAT) adopted a pro-inflammatory phenotype (CCL5, TIMP-1) in WT mice, exacerbating DTA damage, while Rag1-/- mice showed thermogenic plasticity (Ucp1 upregulation) in abdominal PVAT (A-PVAT). T cell reconstitution restored maladaptive remodeling in Rag1-/- mice, confirming adaptive immunitys dual role in promoting thoracic injury and restraining metabolic resilience. This work identifies PVAT as an immune-metabolic switch governing regional susceptibility to vascular remodeling, offering spatially resolved strategies to preserve aortic compliance in hypertensive disease.

BackgroundIndividuals affected by obesity present different health trajectories and do not suffer from cardiometabolic complications all in the same way. There is a need to better understand obesity subtypes and to develop approaches for stratification. In this study we investigated both metabolomic and proteomic signatures in serum and blood plasma samples discriminating metabolically healthy from unhealthy obesity. MethodsWe investigated cross-sectional metabolomic and proteomic data from participants of the Cooperative Health Research in South Tyrol (CHRIS) study. Participants were grouped into metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) based on available health data in the study. A total of 461 individuals were included in the analysis, with n=130 MHO and n=331 MUO. Random forest (RF) classifiers were used to discriminate metabolically healthy from unhealthy obesity and to identify molecular features characteristic of MHO/MUO. Linear regression models were used to assess associations between each relevant metabolite/protein and MHO/MUO phenotypes independently of age, sex and body composition. ResultsThe MHO/MUO RF classifier achieved a performance of AUC = 0.709, 95% CI = (0.698,0.721). Three plasma proteins and 12 circulating metabolites were identified as relevant predictors of MHO/MUO phenotypes. Linear regression models confirmed the Apolipoprotein C-III (APOC3) association to be independent of age, visceral fat composition, medication or serum triglyceride levels. ConclusionAPOC3 was identified as a novel predictor for obesity stratification, highlighting the importance of circulating triglyceride levels in relation to metabolic health.

Hepatic glucose production is crucial for the maintenance of normal glucose homeostasis. Although hepatic insulin resistance contributes to excessive glucose production, its mechanism is not well understood. Here, we show that inositol polyphosphate multikinase (IPMK), a key enzyme in inositol polyphosphate biosynthesis, plays a role in regulating hepatic insulin signaling and gluconeogenesis both in vitro and in vivo.IPMK-deficient hepatocytes exhibit decreased insulin-induced activation of Akt-FoxO1 signaling. The expression of mRNA levels of phosphoenolpyruvate carboxykinase 1 (Pck1) and glucose 6-phosphatase (G6pc), key enzymes mediating gluconeogenesis, are increased in IPMK-deficient hepatocytes compared to wild type (WT) hepatocytes. Importantly, re-expressing IPMK restores insulin sensitivity and alleviates glucose production in IPMK-deficient hepatocytes. Moreover, hepatocyte-specific IPMK deletion exacerbates hyperglycemia and insulin sensitivity in mice fed a high-fat diet (HFD), accompanied by an increase in hepatic glucose production during pyruvate tolerance test and reduction in Akt phosphorylation in IPMK deficient liver. Our results demonstrate that IPMK mediates insulin signaling and gluconeogenesis and may be potentially targeted for treatment of diabetes. HighlightsIPMK expression is reduced in livers of HFD-fed mice. Hepatocyte-specific deletion of IPMK in mice aggravated HFD-induced insulin resistance. Loss of IPMK decreased insulin-induced activation of Akt-FoxO1 signaling, leading to the increase of glucose production in hepatocytes.

BackgroundReverse cholesterol transport by high density lipoproteins (HDL) is considered as an anti-atherogenic metabolic pathway. Hepatocytes determine the efficacy of this pathway by the production of apolipoprotein A-I (apoA-I) and its lipidation by ATP binding cassette transporter A1 (ABCA1), selective uptake of cholesterol via scavenger receptor BI (SR-BI) and uptake of entire HDL particles. The molecular determinants of the latter step are not well understood. MethodsWe performed a genome-wide RNA interference screen for genes limiting the uptake of fluorescent HDL into Huh-7 hepatocarcinoma cells. Top hit genes were validated by targeted in vitro experiments and the analysis of associations between their variants and HDL cholesterol levels in the databases of the Global Lipids Genetics Consortium and UK Biobank as well as inborn errors of metabolism and their respective mouse models. ResultsThe knockdown of 128 genes significantly inhibited HDL uptake. Six of them encode for components of the COPI coatomer, namely COPA, COPB1, COPB2, COPG1, ARCN1, and COPZ1. Knocking down any of them decreased the uptake of both fluorescently labeled proteins and lipids of HDL, the cell surface abundance of SR-BI as well as APOA1 expression and apoA-I secretion but increased the cell surface abundance of ABCA1 as well as cholesterol efflux. Single nucleotide polymorphisms of COPB1, ARCN1, and COPZ2 were associated with significantly higher HDL-cholesterol (HDL-C) levels in the population while rare COPA and COPG1 variants causing immunopathies in humans and mice were associated with low levels of HDL cholesterol. ConclusionsIn hepatocytes, the COPI coatomer regulates HDL holoparticle uptake, selective lipid uptake, apoA-I secretion, and cholesterol efflux, and thereby, it influences plasma levels of HDL-C. HighlightsO_LIBy genome-wide RNA interference screening and replication experiments we found six components of the COPI coatomer, namely COPA, COPB1, COPB2, COPG1, ARCN1, and COPZ1 to limit the uptake of HDL holoparticles into Huh-7 hepatocarcinoma cells, possibly by a mechanism that involves ATP binding cassette transporter ABCA1 C_LIO_LILoss of any of expression of any of these six COPI genes decreases HDL lipid uptake by interfering with the glycosylation and cell surface abundance of scavenger receptor SR-BI C_LIO_LILoss of any of expression of any of these six COPI genes decreases HDL secretion from Huh7 cells, possibly by decreasing gene expression of APOA1 and ABCA1, but despite increasing cell surface abundance of ABCA1 and ABCA1-mediated cholesterol efflux C_LIO_LISingle nucleotide polymorphisms of ARCN1 are associated with significantly higher HDL-cholesterol (HDL-C) levels in the population while rare COPA and COPG1 variants causing immunopathies in humans and mice were associated with rather low levels of HDL cholesterol. C_LI

BackgroundDegenerative protein modifications (DPMs) accumulate with aging and can alter biomolecule structure and function, including via spontaneous conversion of Asn-Gly-Arg (NGR) to isoAsp-Gly-Arg (isoDGR) motifs that can bind integrins and drive chronic inflammation. Since isoDGR-modified extracellular matrix proteins are enriched in atherosclerosis and have been associated with rupture-prone plaque characteristics, we hypothesized that antibody neutralisation can inhibit key pathological features including atherosclerotic vascular plaque formation and metabolic dysfunction. MethodsWe first examined Pcmt1-/- mice which rapidly accumulate isoDGR due to lack of the corresponding repair enzyme to assess the extent of vascular protein damage. We then treated 6-8 week old atherosclerosis-prone (ApoE-/-) mice which were fed a high-fat Western diet (WD) with weekly dose of 1mg/kg isoDGR-specific monoclonal antibody (isoDGR-mAb) or isotype-matched control (while on diet) for 2 months duration. A regular chow-fed ApoE-/- group served as baseline control. Aortic atherosclerotic burden, plaque composition, systemic inflammation, lipid profiles, hepatic steatosis, and metabolic parameters (indirect calorimetry) were assessed. ResultsPcmt1-/- mice displayed extensive isoDGR deposition and degeneration of the aortic wall, linking this DPM to vascular structural damage. In the ApoE-/- mice, WD induced large aortic root plaques with abundant isoDGR and macrophage infiltration. IsoDGR-mAb treatment decreased plaque size by [~]30% with reduced lipid and collagen content (p=0.001). Furthermore, plaques in treated mice contained significantly fewer CD68+ macrophages that also exhibited limited activation. Systemically, isoDGR-mAb modified lipoprotein profiles by decreasing atherogenic VLDL/IDL/LDL cholesterol (p=0.04) while slightly increasing HDL, accompanied by a reduction in circulating inflammatory proteins. IsoDGR-mAb also protected against hepatic lipid accumulation which was reduced by [~]60% in treated animals (p<0.001), with indirect calorimetry confirming [~]30% higher oxygen consumption and energy expenditure without change in food intake or physical activity. ConclusionWe identified isoDGR as a key pathological factor involved in the progression of atherosclerosis. Remarkably, isoDGR neutralization diminished plaque inflammation and improved atherosclerotic plaque stability. Our findings support isoDGR neutralization as a promising therapeutic strategy to mitigate both atherosclerosis and aging-associated metabolic dysfunction.

A new definition of clinical obesity was introduced by the 2025 Lancet Diabetes & Endocrinology Commission to characterize excess body fat and dysfunctional adiposity beyond body mass index (BMI). We performed the first genome-wide analysis (GWAS) of 151,642 cases of clinical obesity and 128,874 controls without obesity from the All of Us Research Program and UK Biobank spanning five ancestry groups and compared these results to GWAS for BMI. We identified 127 independent loci associated with clinical obesity, 63 of which did not share any significant association with BMI. We highlight rs15285 as the most discordant variant, with larger effect size and significance for clinical obesity compared to BMI (delta Z: +6.35, delta -log10 P: 17.67). This variant is located in the LPL gene, colocalized to expression quantitative loci for lipoprotein lipase, and associated with elevated triglyceride levels and proteomic markers of insulin resistance and inflammation. Next, we constructed a clinical obesity polygenic score, which had improved association with cardiovascular risk factors and proteomic markers of inflammation (interleukin-6, fibroblast growth factor 21, hepatic growth factor) and insulin resistance (adiponectin, resistin, leptin, and leptin receptor) over a BMI polygenic score. Stratifying individuals into low, intermediate, and high inherited obesity risk groups, we found that clinical obesity polygenic risk reclassified 35% of individuals compared to BMI polygenic risk. Clinical obesity polygenic risk improved discrimination for myocardial infarction, heart failure and stroke over BMI polygenic risk. We replicated the significant improvement in cardiovascular risk prediction of clinical obesity polygenic scores in Atherosclerosis Risk in Communities, Multi-Ethnic Study of Atherosclerosis, Framingham Heart Study, and Women Health Initiative. These findings demonstrate that clinical obesity captures genetic loci distinct from BMI that are biologically and clinically relevant to cardiovascular health and can improve cardiovascular genetic risk prediction.