Objective

Metabolic reprogramming emerges as a central driver of therapy resistance and survival disadvantage in ovarian cancer. We recently demonstrated that inhibiting the enzyme Deiodinase type 3 (DIO3) reduces ovarian cancer growth, although the underlying mechanism remains unclear.

Methods

We studied DIO3 role in metabolism in genetically manipulated ovarian cancer cells using protein expression analysis, integrative proteomics, endogenous and extracellular metabolomics, metabolic assays including lactate and glutamate secretion, reactive oxygen species (ROS) production and the Seahorse Cell Mito Stress test.

Results

We reveled that inhibiting DIO3 suppresses glycolysis while enhancing ATP production through oxidative phosphorylation (OXPHOS). We corroborated these findings using two models of ovarian cancer xenografts, demonstrating a marked reduction in glycolytic proteins upon silencing or inhibiting DIO3 using our first in class small molecule. Moreover, altered glutamine metabolism was also documented, favoring urea cycle and TCA cycle engagement over antioxidant production, accompanied by elevated ROS. Intriguingly, DIO3 depletion in fallopian tube cells, the precursor of HGSOC, displayed distinct metabolic adaptations, including enhanced glycolysis and lipid metabolism, suggesting tissue-specific roles for DIO3.

Conclusions

These collective findings position DIO3 as a potential regulator of ovarian cancer metabolism, with implications for targeting this enzyme to disrupt tumor energetics as a novel therapeutic approach.

Objectives

Compelling evidence from investigation of preclinical models and humans links canonical Wnt/β-catenin signaling to regulation of many aspects of white adipose tissue development and physiology. Dysregulation of this ancient pathway alters adiposity and metabolic homeostasis. Herein we explore how disruption of adipocyte Wnt/β-catenin signaling affects gene expression and crosstalk between cell types within adipose tissue.

Methods

To investigate mechanisms through which adipose tissue attempts to maintain homeostasis in the absence of β-catenin in adipocytes, we employed standard methods of metabolic phenotyping as well as bulk RNA sequencing, flow cytometry, single-cell RNA sequencing, and isolation of secreted extracellular vesicles.

Results

Our experiments reveal that male, but not female adipocyte-specific β-catenin knockout mice, Ctnnb1^AdKO, have an increase in adiposity and insulin resistance. Whereas metabolic processes including fatty acid metabolism were suppressed in adipocytes, mitochondrial metabolism of immune cells was made more efficient, resulting in reduced reactive oxygen species in macrophages and dendritic cells. Deficiency of β-catenin in adipocytes altered the transcriptome of numerous stromal-vascular cell populations including adipose stem and progenitor cells, macrophages, and other immune cells. Homeostasis in white adipose tissue of Ctnnb1^AdKO mice is maintained in part by elevated expression of Ctnnb1 mRNA in endothelial cells and in secreted small extracellular vesicles.

Conclusions

Our studies demonstrate the importance of adipocyte Wnt signaling for regulation of lipid and mitochondrial metabolic processes in stromal-vascular cells and adipocytes in adipose tissues. This research provides further support for an intercellular Wnt signaling network with compensatory capability to maintain homeostasis, and underscores importance of Wnt/β-catenin signaling for understanding adipose tissue physiology and pathophysiology.

Objectives

Cold-triggered adaptation of the brown adipose tissue (BAT) promotes increased non-shivering thermogenesis and helps maintain body temperature. This study investigated the role of the secreted protein developmental endothelial locus-1 (DEL-1) in regulating BAT adaptation to cold.

Methods

DEL-1 expression in BAT was assessed following cold exposure in mice. The role of DEL-1 in cold-induced BAT adaptation, thermogenesis and proliferation of brown adipocyte progenitor cells was analyzed by utilizing genetically modified mouse models. Mechanistic insights into DEL-1-mediated regulation of brown adipocyte progenitor proliferation were obtained through in vitro assays.

Results

DEL-1 was expressed in the vascular endothelium of the BAT and its expression was upregulated upon cold exposure. By interacting with αvβ3 integrin on brown adipocyte progenitor cells, DEL-1 promoted their proliferation in a manner dependent on AKT signaling and glycolysis activation. Compared to DEL-1-sufficient mice, DEL-1-deficient mice or mice expressing a non-integrin-binding mutant of DEL-1 carrying an Asp-to-Glu substitution in its RGD motif, displayed decreased cold tolerance. This phenotype was associated with impaired BAT adaptation to cold and reduced brown adipocyte progenitor cell proliferation. Conversely, endothelial-specific DEL-1 overexpression in DEL-1-deficient mice restored the BAT thermogenic response to cold.

Conclusions

Together, the DEL-1/αvβ3 integrin-dependent endothelial-brown adipocyte progenitor cell crosstalk promotes cold-stimulated BAT adaptation. This knowledge could be potentially harnessed therapeutically for promoting BAT expansion towards improving systemic metabolism.

Objectives

A hallmark of type II diabetes is an impairment of the glucose transporter GLUT4 translocation to the plasma membrane of specialized cells in response to insulin. Identifying mechanisms involved in this defect is critical to developing treatments that restore insulin sensitivity. We previously identified a small molecule insulin sensitizer, C59, which improves insulin-stimulated GLUT4 translocation through binding to Unc119b, however, the role and mechanism of Unc119b-mediated regulation of GLUT4 trafficking is unknown.

Methods

Here we use in vitro systems and rodent models of insulin resistance with genetic manipulations of Unc119b expression to uncover the role of this protein in the regulation of glucose homeostasis.

Results

We demonstrate that Unc119b is an endogenous inhibitor of GLUT4 translocation which contributes to the development of insulin resistance in obese individuals. We show that Unc119b interacts with Rac1 and inhibits its activation by insulin, resulting in reduced GLUT4 translocation. Both the prenylated C-terminus of Rac1 and C59 bind to the same site within Unc119b, thus suggesting that C59 enhances GLUT4 translocation by interfering with the action of Unc119b on Rac1.

Conclusions

Overall, this study identifies Unc119b as a critical regulator of glucose homeostasis, uncovers its role in GLUT4 trafficking, and identifies the mechanism of action of a new class of insulin sensitizers.

Objectives

Unlike traditional anti-inflammatory therapies which may interfere with musculoskeletal tissue repair, pharmacological administration of specialized pro-resolving lipid mediators (SPMs) promotes timely resolution of inflammation while stimulating skeletal muscle regeneration. Despite this, the potential role of endogenous inflammation-resolution circuits in skeletal muscle injury and repair remains unknown.

Methods

We investigated the effect of whole-body knockout of leukocyte-type 12/15-lipoxygenase (12/15-LOX) on acute inflammation and regeneration in vivo following skeletal muscle injury in mice. We further tested the impact of 12/15-LOX deficiency on polarization of bone marrow-derived macrophages and differentiation of myogenic progenitor cells in vitro.

Results

Alox15^−/− mice displayed lower intramuscular concentrations of 12/15-LOX-derived lipid mediators than wild type (WT) mice, and this was associated with chronic low-grade muscle inflammation. Alox15-/- mice mounted an exaggerated acute immune response to sterile skeletal muscle injury which was associated with a local imbalance of pro-inflammatory vs. pro-resolving lipid mediators. Alox15^−/− mice also displayed defects in myogenic gene expression, myofiber size, and myonuclear accretion. Mechanistically, bone marrow-derived macrophages (MФ) obtained from Alox15^−/− mice produced less 12/15-LOX-derived lipid mediators and this was associated with impaired M2 polarization. Isolated myogenic progenitor cells also produced many LOX metabolites in response to long chain polyunsaturated fatty acid (LC-PUFA) supplementation, including bioactive SPMs. Alox15^−/− myoblasts were both impaired in their ability to produce SPMs and were insensitive to the stimulatory effect of LC-PUFAs on in vitro myogenesis.

Conclusions

12/15-LOX is essential for timely resolution of acute inflammation and direct determination of myogenic progenitor cell fate following skeletal muscle injury.

Objective

Adipose fibrosis signifies pathological remodeling of white adipose tissue (WAT) associated with insulin resistance, diabetes, and cardiovascular disease. Matrix Gla protein (MGP) balances bone morphogenetic protein (BMP) and transforming growth factor β (TGFβ) signaling but has an unclear role in WAT.

Methods

To study the role of MGP in WAT, we used mice with global or platelet-derived growth factor receptor α (Pdgfra)-Cre-mediated Mgp deletion in adipose progenitor cells (APCs) together with single cell RNA sequencing (scRNA-seq), characterization on adipose and fibrotic phenotypes, and BMP and TGFβ signaling studies.

Results

Our results showed that Mgp deletion promotes fibrosis and impairs adipogenesis in mice with global or Pdgfra-Cre-mediated Mgp deletion in APCs. ScRNA-seq showed two new adipose-derived stem cells (ASC) populations, ASC1 and ASC4, emerging after Mgp deletion. Trajectory analysis found that ASC1 and ASC4 were derived from ASC2, which normally undergo adipogenesis but instead had diverted to fibrogenic differentiation. All three ASCs expressed Pdgfra and dipeptidyl peptidase-4 (Dpp4). Inhibition of TGFβ signaling or DPP4 activity in mice with Pdgfra-Cre-mediated Mgp deletion reduced the size of the PDGFRα+; DPP4+ cell population and rescued the WAT from unwanted fibrosis.

Conclusions

MGP is essential for appropriate balance between adipogenic differentiation and fibroblast activation. Dysregulation of PDGFRα+; DPP4+ cells may signal early adipose fibrosis.

Objective

The single nucleotide polymorphism (SNP) rs1421085 has one of the highest associated risks with obesity of any SNP in the human genome. Through the generation of a novel mouse model harboring rs1421085 (OA-SNP^rs142/rs142), we examined the impact of this SNP on energy balance. Furthermore, we investigated the role of IRX3, a potential mediator of the metabolic effects of rs1421085, in multiple brain regions.

Methods

To explore the impact and mechanisms of rs1421085, we monitored body weight, food intake, energy expenditure, and other metabolic parameters of OA-SNP^rs142/rs142 mice under metabolic conditions similar to human obesogenic conditions (thermoneutral housing and 45% high fat diet). We additionally leveraged this model to investigate the impact of rs1421085 on genes that have been suggested to mediate the effects of this SNP on obesity. Finally, we used Irx3-Cre mice in combination with Cre-dependent AAV-Irx3 to determine if localized induction of IRX3 in neurons was sufficient to drive the energetic effects of rs1421085.

Results

OA-SNP^rs142/rs142 mice are more susceptible to diet-induced obesity and have increased food intake and decreased energy expenditure under human obesogenic conditions. Additionally, OA-SNP^rs142/rs142 mice have elevated Irx3 mRNA expression in the brain with prominent expression in metabolically relevant regions such as the posterior hypothalamus (PH) and dorsal vagal complex (DVC). Increased IRX3 in the PH, but not the DVC, resulted in a significant increase in body weight and food intake. Finally, we found that increased expression of IRX3, specifically in IRX3⁺ neurons, decreases excitability and activity of IRX3⁺ neurons in the PH but not the DVC. Interestingly, inhibition of IRX3⁺ PH neurons led to increased body weight and food intake.

Conclusions

These data demonstrate that OA-SNP^rs142/rs142 mice recapitulate the body weight phenotype associated with rs1421085 in humans and that increased IRX3 in the posterior hypothalamus, as seen in OA-SNP^rs142/rs142 mice, is sufficient to drive some of the metabolic effects of the SNP.

Objectives

We found that the levels of the peroxisomal fatty acid oxidation (FAO) marker in pancreatic ductal adenocarcinoma (PDAC) patients were higher than those in healthy individuals, based on tissue microarray analysis. This study investigates FAO in preclinical in vitro and in vivo models.

Methods

To examine the role of FAO in the peroxisome, we created acetyl-coenzyme A acyltransferase (ACAA1) knockout mice, crossed them with KPC mice, and monitored their survival rates. Additionally, we tested a mouse xenograft model with ACAA1 knockdown in human PDAC cells.

Results

In normal cells, ACAA1 knockdown did not affect oxygen consumption. In contrast, in PDAC cells, ACAA1 knockdown reduced the oxygen consumption rate by up to 60% and decreased ATP production by up to 70%. This suggests that peroxisomes in PDAC supply various acyl-carnitines for FAO in mitochondria. In PDAC cells, ACAA1 knockdown lowered ATP levels, resulting in mTOR inactivation and autophagy induction. Additionally, ACAA1 knockdown significantly increased LC3-II levels, leading to growth retardation in mouse xenograft models. Acaa1a^+/− mice showed a median survival increase of 3 weeks after crossing Acaa1a^+/− with KPC mice (Kras^G12D/+; Trp53^R172H/+; Pdx1-Cre, a genetically engineered mice model for PDAC).

Conclusions

ACAA1 knockdown inhibited tumor growth by triggering autophagy, which supported the survival of KPC mice. The most important benefit of targeting ACAA1 is that it blocks tumor growth specifically in cancer cells without harming normal cell energy metabolism.

Mitochondria are crucial for regulating metabolism, but their role in the placenta and how they may shape offspring metabolism and long-term health remains unclear, despite being commonly associated with pregnancy complications. To investigate this, we used a genetic model with placenta-specific deletion of the mitochondrial calcium uniporter (Pl-MCUKO) and assessed the metabolic trajectory of adult offspring. We found that, at baseline, female placental trophoblasts in wild-type animals exhibited higher respiration rates than males. MCU deletion impaired mitochondrial function specifically in female placentas and was accompanied by distinct changes in the metabolomic profiles of protein and lipid metabolism. Transcriptome analysis revealed reduced placental cellular growth pathways, consistent with smaller placentas and reduced embryonic body weights in Pl-MCUKO. Although in utero MCU deletion affected fetal growth, it was insufficient to cause permanent postnatal changes in body weight, as these deficits normalized in adulthood, with normal glucose homeostasis in Pl-MCUKO offspring. However, when challenged with a high-fat diet, Pl-MCUKO females exhibited reduced weight gain, improved glucose and insulin tolerance, smaller fat depots, and increased ambulatory activity compared to controls. This improved metabolic profile was associated with reduced pancreatic β-cell mass but preserved β-cell function. These findings provide direct evidence that placental mitochondrial function can influence the long-term metabolic health of female offspring by modulating key metabolic tissues.

Objective

The circadian clock anticipates daily repetitive events to adapt physiological processes. In mammals, the circadian system consists of a master clock in the suprachiasmatic nucleus (SCN), which synchronizes subordinate tissue clocks, including extra-SCN central nervous system (CNS) clocks involved in functions such as sleep and appetite regulation. Appetite is controlled by both homeostatic and non-homeostatic (hedonic) circuits. Homeostatic appetite addresses energy needs, while hedonic feeding targets cravings for palatable, calorie-dense foods. The adipokine leptin is a major appetite regulator, interacting with the circadian clock. Although leptin's role in satiation through its action in the mediobasal hypothalamus (MBH) is well established, its involvement in the circadian regulation of feeding remains poorly understood. We hypothesized that circadian gating of leptin signaling in the CNS controls homeostatic and hedonic appetite across the day.

Methods

We analyzed food intake rhythms in mice with a loss of leptin (ob/ob mice) or clock function (Per1/2 or Bmal1 KO) and in mice with specific disruption of leptin circadian gating in the CNS (ObRb.Bmal1).

Results

We found that in leptin-deficient mice hedonic appetite increases specifically in the early rest phase. In contrast, clock-deficient Per1/2 mutant mice exhibit blunted rhythms in both hedonic and homeostatic appetite control. Finally, when clock function is disrupted in leptin-sensitive neurons only, mice display a lower sensitivity to palatable food, along with reduced initial weight gain and adipose hypertrophy under obesogenic diet conditions.

Conclusions

Our data describe a local clock-controlled central leptin gating mechanism that modulates hedonic food intake rhythms and impacts metabolic homeostasis.

Objectives

Oxytocin (OT) is a neuropeptide produced in the paraventricular (PVH) and supraoptic (SON) nuclei of the hypothalamus. Either peripheral or central OT administration reduces food intake through reductions in meal size. However, pharmacological approaches do not differentiate whether OT's influence on food intake is mediated by OT neurons located in the PVH vs. the SON. Here we address this gap using both gain- and loss-of-function approaches targeting OT neurons.

Methods

OT neuron-specific designer receptors exclusively activated by designer drugs (DREADDs) were targeted in either the PVH or SON in rats, thus allowing for evaluation of caloric intake following selective activation of OT neurons separately in each nucleus. To examine the physiological role of distinct OT neuron populations in eating behavior, a viral-mediated approach was used to silence synaptic transmission of OT neurons separately in either the PVH or SON.

Results

DREADDs-mediated excitation of PVH OT neurons reduced consumption of standard chow via reductions in meal size. On the contrary, SON OT neuron activation had the opposite effect by increasing standard chow consumption. Consistent with these opposing outcomes, activation of PVH and SON OT neurons simultaneously had minimal effects on food intake. Additional results from chronic loss-of-function experiments reveal that PVH OT neuron silencing significantly increased consumption of a high fat and high sugar diet by increasing meal size whereas SON OT neuron silencing reduced chow consumption by decreasing meal size.

Conclusions

Collectively these findings suggest that PVH and SON OT neurons differentially modulate food intake by either reducing or increasing caloric consumption, respectively.

Objective

Obesity disrupts metabolic homeostasis through changes in brain function. Hypothalamic cilia and associated proteins, such as the BBSome, a protein complex composed of eight Bardet-Biedl syndrome (BBS) proteins, have been implicated in metabolic regulation and disorders. Here, we investigated the significance of brainstem cilia and the BBSome for energy balance and glucose homeostasis.

Methods

Primary cilia were assessed by immunofluorescence and confocal imaging, and brainstem neuron transcriptomes were analyzed using single-cell RNA sequencing. Mice with Phox2b-specific deletion of Ift88 or Bbs1 were studied under control or high-fat diets. Metabolic tests, insulin signaling, nerve recordings, and viral techniques were used to evaluate the impact of cilia or Bbs1 disruption.

Results

We found that diet-induced obese mice display increased primary cilia length in the nucleus tractus solitarius. Single cell RNAseq revealed that cilia related genes are enriched in glutamatergic dorsal vagal complex (DVC) neurons expressing Phox2b. Primary cilia deletion in Phox2b neurons (Phox2b^Cre/Ift88 ^fl/fl) caused a mild weight reduction during adolescence without altering metabolic homeostasis during adulthood. We next investigated the brainstem BBSome using Phox2b^Cre/Bbs1^fl/fl mice, which exhibited reduced adolescent lean mass gain but normal adult body weight. Surprisingly, these mice developed glucose intolerance and elevated fasting glucose associated with contrasting changes in hepatic sympathetic and parasympathetic activity, pointing to autonomic imbalance as a cause of glucose dysregulation. Targeted BBSome disruption in the DVC replicated elevations in fasting glucose and chemogenetic DVC Phox2b neuron activation attenuated hyperglycemia during glucose tolerance test and suppressed hepatic sympathetic nerve activity. Interestingly, diet-induced obese Phox2b^Cre/Bbs1^fl/fl mice exhibited lower lean mass and a paradoxical improvement in glucose tolerance despite insulin resistance, suggesting a complex role for the brainstem BBSome in obesity-associated metabolic dysfunction.

Conclusions

Our findings highlight novel brainstem mechanisms regulating metabolic homeostasis and distinct roles for primary cilia and the BBSome in glucose regulation and lean mass.

Background

Creatine serves as an intracellular shuttle for high-energy phosphate bonds, enabling rapid ATP transfer from energy-producing to energy-consuming cellular compartments. In skeletal muscle, creatine coordinates energy distribution among mitochondrial oxidative phosphorylation, glycolysis, and the phosphagen system. Consequently, creatine supplementation acutely enhances muscular performance and is widely utilized as an ergogenic aid in power-based sports. Recent studies demonstrate that enhanced creatine metabolism in adipose tissue promotes brown adipocyte renewal and boosts energy expenditure in cold environments or sedentary conditions, thereby improving overall systemic metabolism. Beyond its traditional role as an exercise supplement, the creatine metabolic network has emerged as a promising therapeutic target for metabolic disorders.

Scope of review

This review begins by revisiting the history and latest advancements in creatine research, and ultimately proposes three dimensions for the current explanation of creatine metabolism: (1) subcellular energy transport; (2) muscle-fat metabolic axis; (3) systemic energy sensing and metabolic reprogramming.

Major conclusions

The creatine cycle enables directed energy flow through mitochondrial supercomplexes (VDAC/ANT-CK) and resets systemic metabolism via subcellular energy tunnels and inter-organ interactions. Creatine kinase (CK) condensates, through liquid–liquid phase separation, can rapidly meet energy demands during exercise. Therefore, targeting the dynamics of the CK phase may be promising for enhancing athletic performance and improving metabolic diseases.

Background

Many biological processes from physiological development to different pathological conditions are closely linked to dynamic energetic metabolism and its dysregulations. Mounting evidence shows that metabolic rewiring allows cells to adapt to stress conditions, changes in extracellular cues, and nutritional fluctuations in a timely and precise manner by modulating gene expression. Recent studies reveal non-strictly metabolic functions of metabolic enzymes and related metabolites often confined to the nucleus. Indeed, beyond the diffusion of metabolites through nuclear pores, several metabolic enzymes translocate to the nucleus during cellular differentiation, macrophage activation, tumorigenesis, and so on.

Scope of review

This review aims to outline recent advances in the nuclear functions of metabolic enzymes, focusing on gene expression regulation through transcription factors and epigenetic mechanisms.

Major conclusions

The nuclear localization of metabolic enzymes and metabolites underlines the dual role of metabolism as both a driver and a controller of cellular processes by linking energy metabolism directly to gene expression and cellular reprogramming. The main involvement of respiratory enzymes in nuclear functions suggests a ready interplay between energy status and transcriptional regulation. We trust that these insights will contribute to a more extensive knowledge of the cellular and nuclear landscape and could inspire future investigations on metabolic-mediated gene regulation mechanisms with the aim of developing more effective therapies against diseases.

Objective

In autoimmune Type 1 Diabetes (T1D), aberrant immune activation promotes regulatory T cell (Treg) impairments thereby boosting progression of islet autoimmunity. Consequently, there is a progressive destruction of the insulin-producing beta cells in the pancreas. Controlling overshooting immune activation represents a relevant approach to allow for efficient Treg-targeting by broadening the window of opportunity to induce Tregs.

Methods

We investigated the effect of restricting pyrimidine de novo synthesis during islet autoimmunity and T1D by Dihydroorotate dehydrogenase (DHODH) inhibition using the next-generation DHODH inhibitor Vidofludimus calcium. We assessed Treg-inducing features of DHODH inhibition in T cells from ongoing murine islet autoimmunity and human T1D in vitro. To dissect the functional relevance of these observations, we tested the impact of DHODH inhibition on interfering with autoimmune activation and disease progression in pre-clinical models of T1D in vivo.

Results

We show that DHODH inhibition results in enhanced Treg induction in vitro especially during increased immune activation and reduced T cell proliferation. In addition, Vidofludimus calcium reduced T1D incidence in two mouse models. On the cellular level, treated mice showed reduced T cell activation accompanied by increased Treg frequencies.

Conclusions

We demonstrate that restricting pyrimidine de novo synthesis by next-generation DHODH inhibition is a strategy to interfere with autoimmune activation while fostering Tregs.

Objective

Glucagon-like peptide 1 (GLP-1) receptor (GLP-1R) agonism is foundational to modern obesity pharmacotherapies. These compounds were engineered for maximal G protein alpha(s) (Gsα) signaling potency and downstream cAMP production. However, this strategy requires reconsideration as partial, biased GLP-1R agonists characterized by decreased Gsα signaling and disproportionate reductions in β-arrestin recruitment relative to the native ligand provide greater weight loss than full, balanced agonists in preclinical models.

Methods

We tested the hypothesis that in vitro signaling bias, which considers both cAMP signaling and β-arrestin recruitment, better predicts weight loss efficacy in diet induced obese (DIO) rodents than cAMP potency alone.

Results

Our data demonstrate that signaling bias significantly correlates to GLP-1R agonist mediated weight loss in diet-induced obese mice. We further characterized a protracted GLP-1 analogue (NNC5840) which exhibits a partial-Gsα, cAMP-biased GLP-1R signaling profile in vitro and demonstrates superior maximal body weight reduction compared to semaglutide in DIO mice. The NNC5840 weight loss profile is characterized by reduced in vivo potency but increased maximal efficacy.

Conclusion

The data demonstrate that biased agonism is a strong predictor of in vivo efficacy for GLP-1R agonists independent of factors like intrinsic cAMP potency or pharmacokinetics. These data suggest that drug discovery screening strategies which take a holistic approach to target receptor signaling may provide more efficacious candidate molecules. The interpretations of these studies are limited by unknowns including how structural modifications to the biased GLP-1R agonist effect physiochemical properties of the molecules.

Objective

Sex differences in adipose tissue impact metabolic health, but the underlying molecular mechanisms remain unclear. We previously identified a female-specific chr17 trans-eQTL hotspot regulating mitochondrial gene expression in gonadal white adipose tissue (gWAT). Here, we tested whether iWAT contributes comparably to sex differences in mitochondrial function and futile cycling.

Methods

We analyzed iWAT and gWAT from male and female mice across 58 genetically diverse Hybrid Mouse Diversity Panel (HMDP) strains fed a high-fat, high-sucrose diet. We assessed mitochondrial DNA (mtDNA), oxidative phosphorylation (OXPHOS) and futile cycle gene expression, performed genetic mapping, and measured respiration.

Results

In gWAT, females showed higher mtDNA, OXPHOS expression, and a female-specific chr17 trans-eQTL, correlating with metabolic traits. In contrast, iWAT lacked this hotspot and showed higher mtDNA, OXPHOS expression, and respiration in males. Lipid cycling genes (Lipe, Mgll, Pnpla2) were elevated in male iWAT, while Mpc1, Mpc2, and Pck1 were enriched in female gWAT. Ucp1 was higher in female gWAT but not sex-biased in iWAT. Alpl (TNAP), key creatine cycling gene, was upregulated in females in both depots, particularly in iWAT.

Conclusions

Female gWAT shows genetically driven mitochondrial regulation linked to metabolic protection, whereas male iWAT has higher mitochondrial content, OXPHOS expression, and respiration. Elevated lipolytic enzymes in male iWAT suggest greater FFA release, while higher pyruvate import and glyceroneogenesis genes in female gWAT favor FFA recycling. Alpl upregulation in females indicates sex-biased UCP1-independent thermogenesis. These depot- and sex-specific signatures reflect distinct metabolic strategies and highlight the need to consider both in adipose research.

Objective

Glucagon-like peptide-1 (GLP-1) reduces systemic and gut inflammation. Here we assessed whether gain or loss of GLP-1 receptor (GLP-1R) signaling modifies the extent of gut injury and inflammation in experimental murine acute graft vs. host disease (aGvHD).

Methods

Allogeneic hematopoietic cell transplantation (HCT) was performed using bone marrow and splenocytes from BALB/c donors to induce aGvHD in C57BL/6 recipients or vice versa. Chimerism was determined by flow cytometry analysis of immune cell compartments. Inflammation was assessed by histological scoring of gut mucosal damage and by measuring circulating cytokine levels. qPCR was used to quantify gene expression in small intestine immune cells and tissues. The gut microbiome was assessed by 16S rRNA sequencing.

Results

Allogeneic chimerism was greater than 90% in peripheral blood and in the gut epithelial compartment. Levels of Glp1r mRNA transcripts were induced in the ileum of both vehicle- and semaglutide-treated allogeneic mice, reflecting that allogeneic T cells homing to the gut express a functional GLP-1R. Nevertheless, semaglutide did not attenuate the severity of systemic cytokine induction, gut injury or inflammation, or the extent of aGvHD in the gut mucosa. Loss of GLP-1R signaling in donor cells had limited effects on overall microbial diversity during acute GvHD, and semaglutide-treated mice exhibited modest changes in proportions of microbial species.

Conclusions

Although gut T cells express a functional GLP-1R, GLP-1R signaling has no meaningful impact on systemic or intestinal inflammation or microbiota composition in mice with experimental aGvHD, highlighting that the anti-inflammatory actions of GLP-1 medicines are highly context-dependent.