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.

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.

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

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.

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.

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.

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.

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

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.

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.

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.

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 [&ge;]2 MO individuals from one cohort and in [&ge;]1 MO individual from the other; among these, 27 variants occurred in [&ge;]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.

Clearance of circulating insulin is critical for metabolic homeostasis. In the liver, insulin is degraded by the activity of the insulin-degrading enzyme (IDE). Here we establish a hepatic regulatory axis for IDE through WDR23-proteostasis. Wdr23KO mice have increased IDE expression, reduced circulating insulin, and defective insulin responses. Genetically engineered human cell models lacking WDR23 also increase IDE expression and display dysregulated phosphorylation of insulin signaling cascade proteins, IRS-1, AKT2, MAPK, FoxO, and mTOR, similar to cells treated with insulin, which can be mitigated by chemical inhibition of IDE. Mechanistically, the cytoprotective transcription factor NRF2, a direct target of WDR23-Cul4 proteostasis, mediates the enhanced transcriptional expression of IDE when WDR23 is ablated. Moreover, an analysis of human genetic variation in WDR23 across a large naturally aging human cohort in the US Health and Retirement Study reveals a significant association of WDR23 with altered hemoglobin A1C (HbA1c) levels in older adults, supporting the use of WDR23 as new molecular determinant of metabolic health in humans.

IntroductionInflammation is a key pathogenic feature of abdominal aortic aneurysm (AAA). Soluble epoxide hydrolase (sEH) is a pro-inflammatory enzyme that converts cytochrome P450-derived epoxides of fatty acids to the corresponding diols, and pharmacological inhibition of sEH prevented AAA formation. Both cytochrome P450 enzymes and sEH are highly expressed in the liver. Here, we investigated the role of hepatic sEH in AAA using a selective pharmacological inhibitor of sEH and hepatocyte-specific Ephx2 (which encodes sEH gene) knockout (KO) mice in two models of AAA [angiotensin II (AngII) infusion and calcium chloride (CaCl2) application]. Methods and resultssEH expression and activity were strikingly higher in mouse liver compared with aorta and further increased the context of AAA, in conjunction with elevated expression of the transcription factor Sp1 and the epigenetic regulator Jarid1b, which have been reported to positively regulate sEH expression. Pharmacological sEH inhibition, or liver-specific sEH disruption, achieved by crossing sEH floxed mice with albumin-cre mice, prevented AAA formation in both models, concomitant with reduced expression of hepatic sEH as well as complement factor 3 (C3) and serum amyloid A (SAA), liver-derived factors linked to AAA formation. Moreover, sEH antagonism markedly reduced C3 and SAA protein accumulation in the aortic wall. Co-incubation of liver ex vivo with aneurysm-prone aorta resulted in induction of sEH in the liver, concomitant with upregulation of Sp1, Jarid1b, C3 and SAA gene expression, suggesting that the aneurysm-prone aorta secretes factors that activate sEH and downstream inflammatory signaling in the liver. Using an unbiased proteomic approach, we identified a number of dysregulated proteins [e.g., plastin-2, galectin-3 (gal-3), cathepsin S] released by aneurysm-prone aorta as potential candidate mediators of hepatic sEH induction. ConclusionWe provide the first direct evidence of the livers role in orchestrating AAA via the enzyme sEH. These findings not only provide novel insight into AAA pathogenesis, but they have potentially important implications with regard to developing effective medical therapies for AAA.