Metabolism

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.

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.

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.

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.

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.

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

Background/Objectives: Childhood appetitive traits are heritable behavioural phenotypes hypothesized to link genetic susceptibility to obesity risk. Yet their genetic architecture and role in mediating polygenic adiposity risk remain poorly understood. Methods: We conducted the largest survey of childhood eating behaviour to date, allowing us to perform genome-wide association studies of six appetitive domains derived from 18 items of the parent-reported Children's Eating Behaviour Questionnaire in up to 31,018 eight-year-old children from the Norwegian Mother, Father and Child Cohort Study (MoBa). A trio-based design enabled decomposition of direct and indirect genetic effects on appetite and BMI. Results: We identified ten independent genome-wide significant loci for childhood eating behaviour, primarily across Food Responsiveness, Satiety Responsiveness, and Food Fussiness, eight of which lie at established childhood or adult BMI loci. Food Responsiveness and Satiety Responsiveness showed both phenotypic and genetic correlations with BMI trajectories from early childhood through adolescence. Statistical mediation analyses indicated that 22.1% and 10.4% of the aggregated genetic association with BMI at age 8 could be decomposed through these traits, respectively. Locus-specific patterns further suggested mechanistic pathways, with the FTO locus acting predominantly via Food Responsiveness, and the ADCY3 locus via Satiety Responsiveness. Trio analyses demonstrated that both BMI and eating behaviour associations were predominantly explained by children's inherited alleles, with minimal contribution from indirect effect from parental adiposity, although parental genetic liability influenced reporting of Satiety Responsiveness. Conclusions: Childhood appetitive traits capture a substantial proportion of genetic susceptibility to adiposity through distinct eating behaviour pathways (under standard mediation assumptions). These effects are primarily driven by the child's own genotype rather than indirect parental influences, positioning appetite as a plausible, biologically grounded target for early obesity prevention.

Endothelial dysfunction is a hallmark of numerous vascular pathologies and is strongly influenced by mechanobiological forces within the vascular microenvironment. While the effects of shear stress have been extensively investigated, the mechanisms by which elevated hydrostatic pressure regulates endothelial junctional organisation remain sparsely investigated. Here, we employed a microfluidic platform to investigate the combined effects of low shear stress (1.4 dyne/cm2) and elevated hydrostatic pressure (~3972 Pa) on endothelial junctional dynamics. Elevated hydrostatic pressure induced marked remodelling of VE-cadherin junctions, characterised by formation of serrated, finger-like structures accompanied by increased YAP1 nuclear localisation and reduced YAP1-VE-cadherin cytoplasmic colocalisation compared to shear stress alone conditions. Further, elevated hydrostatic pressure also demonstrated an increase in cytoplasmic accumulation of EPS8, an actin adaptor protein, and increased cytoplasmic EPS8-VE-cadherin colocalisation. These observations were accompanied by functional changes marked by increased endothelial permeability, and enhanced THP-1 monocyte adhesion, thus suggesting activation of mechanosensitive pathways linked to dynamic junctional reorganisation. Inhibition of PI3K at elevated hydrostatic pressure exhibited a thin VE-cadherin patterning and increased cytoplasmic EPS8-VE-cadherin colocalisation, thus demonstrating a prominent role for PI3K signalling in regulating the junction organisation. Interestingly, Piezo-1 activation using Yoda1 produced context-dependent effects. Under shear stress alone, Yoda1 promoted YAP1 nuclear translocation, reduced YAP1-VE-cadherin colocalisation, increased endothelial permeability but strikingly did not impact THP-1 adhesion compared to shear stress alone conditions. In contrast, under elevated hydrostatic pressure conditions, Yoda1 significantly reduced both endothelial permeability and THP-1 adhesion while increasing YAP1-VE-cadherin colocalisation and decreasing YAP1 nuclear accumulation. Collectively, these findings identify a previously underappreciated elevated hydrostatic pressure-Piezo-1-PI3K signalling axis that regulates endothelial barrier integrity and pro-adhesive endothelial activation through coordinated regulation of VE-cadherin, YAP1, and EPS8. These results highlight elevated hydrostatic pressure as a unique mechanobiological stimulus, distinct from that of shear stress alone and provide novel insights into mechanisms underlying microvascular dysfunction.

Pancreatic ductal adenocarcinoma (PDAC) is commonly associated with obesity, diabetes, and cachexia. The pancreatic anabolic hormone, insulin, is implicated in each of these metabolic diseases, but how insulin levels affect tumor growth and relevant host physiological factors, was unclear. To address this, we transplanted orthotopic PDAC patient-derived organoids into mice consuming a hyperinsulinemia-inducing high-fat diet (HFD). We found that insulin concentrations were higher in tumors compared to circulation. Genetically reducing insulin levels reduced PDAC growth, particularly in HFD-fed mature male mice. In turn, we found the presence of pancreatic tumors increased glucose clearance and limited the expected dietary-induced gains in insulin, weight and fat mass. Interestingly, tumor growth in normal-chow-fed mice, but not HFD-fed mice, was associated with declining circulating insulin levels, as well as declines in fat and muscle mass. Together, these data provide new insights into the complex, insulin-centred interplay between PDAC and the hosts systemic metabolism that underlie cancer-associated metabolic dysfunction.

BackgroundCardiovascular disease risk is higher in men than in women. Although sex differences in aortic wall adaptation following antihypertensive treatment have been reported in acute hypertension models, the response after gradually developing hypertension, which mimics human essential hypertension, remains unclear. This study investigated sex differences in aortic wall adaptation following acute blood pressure reduction after gradually developing hypertension. MethodSeventeen-week-old spontaneously hypertensive rats (SHRs) were assigned to the Hypertensive group or the antihypertensive (Reversal) group (N = 5/sex each). The Reversal group received the antihypertensive drug captopril for 4 weeks to maintain systolic blood pressure below 130 mmHg. Age-matched Wistar Kyoto rats (N = 3/sex) served as normotensive (Normal) group. After the experimental period, arterial wall thickness, circumferential wall stress, smooth muscle cell phenotype, and histological changes were evaluated. ResultsAntihypertensive treatment significantly reduced systolic blood pressure in both sexes. Both male and female SHRs exhibited elevated circumferential wall stress during the gradual development of hypertension. In females, antihypertensive treatment significantly reduced medial thickness compared with the Hypertensive group, whereas males showed no reduction. Circumferential wall stress in female Reversal group did not differ significantly from either the Hypertensive or Normal group, whereas males exhibited a significant reduction in circumferential wall stress compared with the Hypertensive group. Furthermore, the reduced collagen area fraction in the Hypertensive group returned to the normotensive levels only in females following antihypertensive treatment. ConclusionThese findings indicate that vascular remodeling induced by gradually developing hypertension is more effectively reversed by antihypertensive treatment in females than in males.

Angiotensinogen (AGT) deletion in hepatocytes reduces Western diet-induced adiposity and hepatic steatosis in mice maintained under conventional room-temperature (RT) housing. Given the high metabolic activity of mice, this temperature imposes adaptive metabolic responses in this species. Whether this metabolic protection persists independent of increased thermogenic demand remains unclear. In this study, we first determined whether thermoneutral housing (TN, 30 {degrees}C) alters Western diet-induced metabolic phenotypes compared with RT housing (20 {degrees}C) in wild-type mice. Although body weight did not differ significantly between housing conditions, Western diet-fed mice housed at TN exhibited brown adipose tissue whitening and more pronounced hepatic steatosis than mice housed at RT, confirming that thermoneutrality exacerbated diet-induced metabolic dysfunction. We then housed hepatocyte Agt deficient (hepAGT-/-) mice and wild-type (hepAGT+/+) littermates at TN and fed them Western diet for 12 weeks. Despite enhanced metabolic dysfunction under TN, hepatocyte AGT deletion resulted in reductions in diet-induced body weight gain, fat mass, liver weight, and hepatic triglyceride accumulation. Bulk RNA sequencing of liver revealed hepatocyte AGT deficiency-dependent alterations in lipid-metabolic pathways. Cross-temperature analysis of RT and TN housing identified 35 shared differentially expressed genes, including 27 concordantly downregulated genes enriched in lipid metabolism and transport. Extended Western diet feeding for 24 weeks confirmed sustained reductions in body weight gain, liver weight, and hepatic lipid accumulation in hepAGT-/- mice. These findings demonstrate that hepatocyte AGT deletion provides sustained protection against Western diet-induced metabolic dysfunction under thermoneutral housing, a condition that more closely recapitulates human basal metabolism. NEW & NOTEWORTHYThis study investigated hepatocyte angiotensinogen (AGT) biology during Western diet feeding in mice under thermoneutral housing, a condition relevant to human metabolism. By minimizing adaptive thermogenesis induced by standard room temperature housing, thermoneutrality more closely recapitulates human basal metabolic conditions. Under this condition, hepatocyte AGT deletion remains protective against adipo and hepatic lipid accumulation, despite exacerbated Western diet-induced metabolic dysfunction in wild-type mice, demonstrating that this protection persists in a human-relevant thermal environment. GRAPHIC ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=132 SRC="FIGDIR/small/742617v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@1ac7094org.highwire.dtl.DTLVardef@131cfforg.highwire.dtl.DTLVardef@d4dba6org.highwire.dtl.DTLVardef@a09acc_HPS_FORMAT_FIGEXP M_FIG C_FIG

Background Lifestyle interventions are central to obesity prevention and management, yet interindividual variability in response remains incompletely understood. Here, we leveraged genetically defined, distinct obesity endotypes to examine lifestyle-body mass index (BMI) associations across biological pathways. Methods In the UK Biobank, we analyzed 305,713 participants with partitioned polygenic scores (pPSs) representing 10 obesity endotypes. We evaluated interactions between endotype-specific genetic susceptibility and physical activity, diet, sedentary behavior, and sleep on BMI using multivariable linear regression. Primary findings were externally evaluated in the All of Us Research Program using Fitbit-derived lifestyle measures. Results Favorable lifestyle behaviors were associated with lower BMI for all obesity endotypes, but the magnitude of these associations varied significantly across endotypes. Higher endotype-specific pPSs strengthened the benefits of physical activity (7 endotypes), healthy diet (3 endotypes), nonsedentary behavior (5 endotypes), and adequate sleep (7 endotypes) on BMI. Distinct endotypes demonstrated the greatest responsiveness to different lifestyle domains, with the metabolically unhealthy endotype showing the strongest interaction with physical activity, metabolically healthy endotype with sedentary behavior, hypothalamic dysregulation endotype with diet, and hypoinsulin 2 endotype with sleep, corresponding to differences in BMI of 0.22-0.49 kg/m2 between the highest and lowest pPS deciles. These interaction patterns were consistent in the All of Us cohort. Conclusions Obesity endotypes modify the association between lifestyle behaviors and BMI, demonstrating that responsiveness to lifestyle behaviors is heterogeneous and pathway dependent. These findings provide a framework for precision obesity prevention by identifying individuals who may derive greater benefit from specific lifestyle interventions.

Body mass index (BMI) alone may underestimate clinically relevant obesity because it does not capture central fat distribution. We compared obesity prevalence in Mexico using BMI-only criteria, adiposity-confirmed criteria, and the clinical obesity definition proposed by the Lancet Diabetes and Endocrinology Commission. We conducted a population-based, cross-sectional study of 13,160 adults aged 18 years or older who participated in the 2018-2019 Mexican National Health and Nutrition Survey (ENSANUT). Obesity prevalence was estimated through survey-weighted analyses that accounted for the complex sampling design. The weighted prevalence of obesity based on BMI was 34.5% (95% CI, 33.1-35.9), while 30.9% (95% CI, 29.6-32.2) met criteria for clinical obesity. One quarter of individuals with clinical obesity had a BMI under 30 kg/m2, a phenotype more common among older adults. Half of adults with a BMI under 30 kg/m2 showed elevated central adiposity. BMI alone underestimates clinically relevant obesity in Mexican adults. Adding waist-based measurements could improve the identification of individuals with excess fat and metabolic risk, both in clinical settings and population monitoring.

The role of 2-hydroxyglutarate in lipid metabolism is currently unknown. Here we show that 2HG redistributes the partitioning of fatty acids into triglyceride storage and away from membrane phospholipid synthesis, mitochondrial oxidation, and lipotoxic intermediates. In primary human cardiac and vascular cells, both enantiomers, D2HG and L2HG, expanded triglyceride stores and lipid droplets while selectively depleting phosphatidylethanolamine, with L2HG acting more potently than D2HG despite lower intracellular accumulation. Mechanistically, L2HG increases DGAT-dependent triglyceride synthesis, slows triglyceride turnover, and constrains the ethanolamine branch of the Kennedy pathway. This response limits fatty acid oxidation, long-chain acylcarnitine accumulation, and lipid peroxidation independently of pseudohypoxic transcription or canonical lipid storage regulators, while also remodeling the phosphoproteome and redox proteome. L2HG accumulation induces hypertriglyceridemia in mice, redistributes the acyl chain composition of cardiac triglycerides, and limits ischemia-induced acylcarnitine accumulation in the heart, mirroring a positive association between circulating 2HG and triglycerides in humans. Thus, 2HG expands metabolic flexibility from whether fatty acids are used as fuel to how that fuel is allocated among storage, membrane synthesis, and oxidation.

Background & Aims: Fatigue is a central symptom of chronic liver disease (CLD), substantially impacting health-related quality of life (HRQoL). This study aimed to further understand CLD symptomatology, including fatigue, and its impact on HRQoL from a patient perspective. Methods: Abbott Global Assessment of Patients unmet needs (aGAP) was a multinational, cross-sectional survey in adults with compensated CLD in China, India and Mexico, conducted between July and November 2024. Adult participants who self-reported that they had physician-diagnosed CLD and were experiencing fatigue completed a quantitative survey to assess symptom burden and included three HRQoL patient-reported outcome (PRO) questionnaires (Patient-Reported Outcomes Measurement Information System [PROMIS]-29+2, Work Productivity and Activity Impairment - Specific Health Problem version 2.0 [WPAI: SHP], Multidimensional Fatigue Inventory [MFI]). Results: Overall, 505 participants (China: 200; Mexico: 105; India: 200) completed the study. Participants reported that their CLD-related fatigue sometimes, often or always affected their self-esteem/confidence (45.1%) and ability to maintain or acquire new employment (38.6%). Most participants reported moderate (51.3%) or serious (26.9%) fatigue, with 33.5% experiencing fatigue every day or almost every day. Many participants felt their social life was negatively impacted by their fatigue (47.3%) and that there were related financial difficulties (53.9%). Use of validated PRO tools demonstrated severe fatigue (MFI: overall mean [SD] 13.9 [3.4] general fatigue and 13.4 [3.6] physical fatigue) as well as substantial levels of work and activity impairment (WPAI: SHP overall mean [SD] 53.0 [26.4]) and high levels of anxiety, pain interference, depression and sleep interference (PROMIS T-scores [≥]54). Conclusions: Fatigue has a substantial impact on HRQoL among adults with CLD across several countries, highlighting a global unmet need for targeted interventions to effectively identify and manage the condition.

Background and AimsPregnancy requires dynamic, stage-specific adaptations in maternal liver metabolism and growth to sustain fetal development while preserving systemic homeostasis. Estrogen signaling, which significantly increases during pregnancy, is primarily mediated in hepatocytes by estrogen receptor (ER). Although hepatic ER regulates female liver metabolism under non-pregnant conditions, its role in pregnancy-induced hepatic remodeling remains unclear. MethodsWe studied non-pregnant and pregnant control and liver-specific ER knockout (LERKO) mice across gestational stages using longitudinal physiological measurements, liver transcriptomics, targeted metabolomics, histological assessment of cell proliferation, and metabolic phenotyping. ResultsIn control mice, pregnancy elicited sequential hepatic remodeling characterized by early induction of cell-cycle programs, a mid-gestational peak in hepatocyte proliferation with transient suppression of selected metabolic pathways, and late reactivation of specific metabolic programs. Chronic hepatic ER deficiency alters this temporal pattern. LERKO livers showed premature activation of proliferative and anabolic transcriptional programs, changes in amino acid- and fatty acid-related metabolic pathways, and altered temporal regulation of AKT-mTORC1-related signaling. At mid-gestation, LERKO mice displayed reduced hepatocyte proliferation, altered expression of metabolic and insulin-related genes, blunted gestational glucose adaptation without overt evidence of systemic insulin resistance, and changes in the light/dark-phase metabolic patterns. ConclusionsThese findings suggest that hepatic ER is required for the appropriate stage-specific coupling of liver growth, metabolic remodeling, and insulin-responsive signaling during pregnancy. Its loss is associated with gestational hepatic maladaptation and systemic metabolic phenotypes, providing a framework for investigating estrogen-dependent mechanisms underlying pregnancy-associated metabolic and liver disorders. HighlightsHepatic ER is required for stage-specific liver remodeling during pregnancy. Loss of hepatic ER alters temporal coupling of liver growth and metabolism. LERKO mice show early changes in amino acid- and fatty acid-related pathways. Hepatic ER loss reduces proliferation and alters gestational glucose adaptation. Hepatic ER loss is associated with altered light/dark-phase metabolic organization. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=80 SRC="FIGDIR/small/743939v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@d52bborg.highwire.dtl.DTLVardef@b27511org.highwire.dtl.DTLVardef@23b286org.highwire.dtl.DTLVardef@19d9314_HPS_FORMAT_FIGEXP M_FIG C_FIG

MTCH2 (mitochondrial carrier homolog 2) is a noncanonical member of the solute carrier family with five transmembrane (TM) helices, localized to the mitochondrial outer membrane. MTCH2's atypical topology creates a membrane-accessible hydrophilic groove, predicted to be necessary for its protein insertase and lipid scramblase activities. MTCH2 is linked to lipid metabolism and obesity and is required for starvation-induced mitochondrial hyperfusion. Here, we show that MTCH2 is a stable component of a complex containing the Armadillo (ARM) repeat-containing protein, ARMC1, and the DnaJ/Hsp40 chaperone protein, DNAJC11. Protein crosslinking, protein structural modeling, and molecular dynamics simulations demonstrate that the ARMC1 alpha-helical C-terminal domain (CTD) inserts into and stably interacts with the MTCH2 hydrophilic groove and blocks its lipid scramblase activity. We observe that starvation-induced mitochondrial fatty acid oxidation (FAO) is negatively regulated by the ARMC1-MTCH2 interaction. In ARMC1-deficient cells, FAO is stimulated compared to wild-type cells and lipid droplet abundance is significantly reduced. The altered lipid phenotype of ARMC1-/- cells is strictly dependent on MTCH2 and is reversed by ARMC1 expression in a manner dependent on its CTD. Beyond this metabolic axis, we also identify a function for ARMC1 in regulating lysosomal distribution and autophagic flux that is independent of its CTD and interaction with MTCH2. Thus, our data support a model in which the MTCH2-ARMC1 interaction functions as a metabolic switch during starvation to regulate the balance between fat storage and fat burning.

Glucagon is a key metabolic hormone regulating blood glucose and appetite, yet little is known about its actions within the brain. Here, we investigated its receptor (GCGR) localization in periventricular brain barrier interfaces in young rats using immunohistochemical and immunofluorescence approaches. GCGR was enriched in the proximal region of motile ependymal cilia lining the ventricles, as well as in tanycytic primary cilia and cytoplasmic extensions within the hypothalamus. Additional immunostaining was observed in ciliated cells of the subcommissural organ and, more heterogeneously, in choroid plexus epithelium and associated primary cilia, while other circumventricular organs lacked detectable GCGR. These findings identify brain cilia and tanycytes as previously unrecognized sites of glucagon receptor localization and suggest that glucagon signaling at brain barrier interfaces may contribute to integrating peripheral metabolic cues with central homeostatic circuits.

Polygenic risk scores (PRS) have emerged as promising tools for stratifying inherited disease risk, yet their translation into clinical practice is constrained by a critical and frequently unmet requirement: demonstration that scores derived in one cohort retain discriminatory value when applied independently in a different population. For suspected familial hypercholesterolemia (FH), a substantial proportion of patients that meet clinical criteria still test negative for a monogenic cause. These patients are presumed to carry polygenic LDL-C burden, yet PRS validation is still scarce. Here, we evaluated a published hypercholesterolemia PRS (PGS000936) spanning 5,386 genome-wide loci. We tested the score in 117 monogenic-negative hypercholesterolemia cases and 496 controls from the German general population genotyped on the Illumina Global Screening Array v3.0, with imputation to approximately 11 million variants. The score was applied without retraining, using externally derived {beta}-coefficients. The PRS clearly distinguished cases from controls (p < 2x10-16), with a mean PRS of 0.97 in cases versus 0.52 in controls. Decile analysis revealed a seven-fold increase in odds of hypercholesterolemia in the top 10% of the distribution (OR 7.55; 95% CI 4.36-13.07; p < 0.0001). In 94 cases for which clinical data was available, higher PRS was associated with significantly higher LDL-C levels before treatment. Importantly, the PRS distribution in the German control cohort was shifted relative to that of the control cohort in the initial study, suggesting that population-matched calibration is required for accurate odds ratio estimation and proper interpretation of PRS values. These findings show that the published hypercholesterolemia PRS (PGS000936) can effectively stratify risk and identify individuals with a high genetic burden in a real-world German clinical setting, supporting its clinical utility when appropriately calibrated for the local population.

Left ventricular hypertrophy, common in cardiometabolic and renal disease, is a major risk factor for cardiovascular morbidity and mortality. Left ventricular mass is a highly heritable, polygenic trait. Linkage studies in WKY and SHRSP rats have identified a quantitative trait locus for left ventricular mass index on chromosome 14. Congenic strains, where trait-associated genetic loci are introduced into a control strain, can identify causal genetic mediators relevant to human disease. Chromosome 14 congenic (WKY.SPGla14a), WKY, and SHRSP strains underwent cardiac phenotyping and transcriptome profiling at; 1-3 days (neonate), 5 weeks, and 16-weeks. Compared to WKY, LVMI was significantly increased in SHRSP and WKY.SPGla14a at 5 weeks (LVMISHRSP-WKY=0.26g/kg, LVMIWKY.SPGla14a-WKY=0.30g/kg), prior to measured hypertension in this model. SHRSP blood pressure was significantly greater than WKY.SPGla14a, and WKY from 12-20 weeks (AUCdiff=497 vs WKY, AUCdiff=412 vs WKY.SPGla14a). Cardiac transcriptome analysis of neonate, 5-week, and 16-week hearts identified significantly increased expression of secreted phosphoprotein 1 (Spp1/osteopontin) in SHRSP and WKY.SPGla14a compared to WKY, which is positioned within the transferred congenic region. Overexpression of Spp1 mRNA significantly increased H9c2 cell size and was shown to be transferred in small extracellular vesicles (sEV). Overexpression of Spp1 in neonatal chromosome 14 congenic and SHRSP strains preceded development of increased cardiac mass and onset of hypertension. The congenic strategy identified Spp1 as a positional and functional candidate gene determining increased LVMI in the SHRSP model of human cardiovascular disease.