Nature Metabolism

Overconsumption of foods rich in fats, sugars, and calories is a major contributing factor to increased risk for cardiometabolic disease. Ingestive experience with these foods can begin early in children, yet there is limited understanding of the impact of early life nutrition on the development of vagal afferent neurons necessary for coordinating appetitive and satiating behaviors. To this end, mice reared on a chow diet (control) were compared to those reared on a high-fat diet (HFDEARLY). We demonstrate that the vagally-mediated satiation response to cholecystokinin (CCK) does not mature until adolescence in chow-reared mice. However, HFDEARLY exposure triggers a precocious maturation of this response, accompanied by transcriptomic changes in the nodose ganglion. Durable changes in appetitive behaviors were also evident in adult HFDEARLY mice, which consumed more lipid than control mice. Behavioral analyses point to alterations in orosensory integration and enhanced appetition in adult HFDEARLY mice, establishing nutrient exposure as a significant contributor to vagal circuit maturation and function.

Lower familial socioeconomic status (SES) is linked to increased childhood disease risk. Since SES has no inherent biological basis, identifying how it becomes physiologically embedded is essential for equitable intervention. Using data from the CHILD cohort, we analyzed modifiable pathways linking SES to child health and found that the infant gut microbiota plays a key mediating role. Breastfeeding was associated with a stabilized infant microbiota, buffering against environmental impacts and reducing health risks in lower SES contexts. The presence of Bifidobacterium infantis, enriched through breastfeeding, was linked to protection against adverse outcomes from SES. We observed similar associations in the independent COPSAC2010 cohort, including links among SES, breastfeeding, child health, the microbiota, and B. infantis. Together, these results suggest the improving breastfeeding rates and restoring breastfeeding-enriched microbes, like B. infantis, may help buffer early biological impacts of social inequality and support healthier trajectories for children growing up in industrialized settings. One-Sentence SummaryBreastfeeding limits the adverse impact of socioeconomic status on child risk factors associated with non-communicable diseases potentially by modifying infant gut microbiota and enriching for Bifidobacterium infantis.

Fetal growth restriction (FGR) subjects exhibit altered metabolism, with higher metabolic rate due to their small body mass, and by adopting strategies to minimise energy expenditure. We investigated how these metabolic differences develop, or manifest in growth trajectories, after FGR, small for gestational age (SGA) (constitutionally small), and normal pregnancies. We curated a unique composite dataset of 1934 subjects between 14 weeks of gestation and 5 years of age. First, we assessed fetal and infant heart rate to assess whether higher metabolic rate persisted postnatally after FGR. Next, as the largest energy expenditure is brain synaptic maintenance, we tested whether FGR infants had lower white matter volume (proxy for synapse number). Finally, we modelled longitudinal body weight into childhood in FGR, SGA, and control groups, and tested for associations with neurodevelopmental scores at 1-2 years. Heart rate at rest was higher in FGR fetuses and infants (688 subjects), and FGR infants exhibited a blunted capacity to increase heart rate to a nociceptive procedure (i.e. a physiological challenge). FGR infants had smaller white matter volume (270 subjects). Finally, the more an individuals weight gain deviated below average curves (1714 subjects), the lower were their motor and cognitive scores at 1-2 years.

Very preterm birth disrupts critical fetal developmental programs, yet the systemic molecular trajectories driving extrauterine adaptation remain poorly defined. Although extracellular vesicles (EVs) represent informative systemic compartments, comprehensive multi-omics is constrained by the small plasma volumes safely obtainable from neonates. Here, we adapted a magnetic bead-based framework (Mag-Net) to enable parallel EV proteomics and lipidomics from the same EV-enriched preparation using 10 {micro}L of plasma. Across 74 longitudinal samples collected from birth to term-equivalent age, we quantified 1,528 EV-associated proteins and 421 lipid species. The EV proteome shifted from early translation and metabolic programs toward progressive immune competence, while the lipidome underwent selective structural remodeling enriched in triacylglycerols and ether-linked phosphatidylcholines. Cross-omics integration identified coordinated protein-lipid modules associated with clinical phenotypes, including brain injury. This study demonstrates that parallel EV proteomic-lipidomic profiling from microliter plasma volumes is feasible and captures coordinated developmental and clinically relevant programs in very preterm infants.

Gene-environment interactions shape animal behavior and the susceptibility to neurobehavioral symptoms such as depression. However, little is known about the signaling pathway that integrates genetic and environmental inputs with neurobehavioral outcomes, preventing the development of targeted therapies. Here we report that Gpr35 engages a gut microbe-to-brain metabolic pathway to modulate neuronal plasticity and depressive behavior in mice. Chronic stress decreases gut epithelial Gpr35, the genetic deletion of which induces despair and social impairment in a microbiome-dependent manner. We identify a dominant role for the imbalance of microbe-derived indole-3-carboxaldehyde (IAld) and indole-3-lactate (ILA) in the behavioral symptoms with Gpr35 deficiency. Mechanistically, these bacterial metabolites counteractively modulate dendritic spine density and synaptic transmission in the nucleus accumbens. Supplementation of IAld, which is similarly decreased in depressive patients, produce anti-depressant effects in mice with stress or gut epithelial Gpr35 deficiency. Together, these findings identify a genetics-shaped gut-brain connection underlying the susceptibility to depression and suggest a microbial metabolite-based therapeutic strategy to genetic predisposition.

Amylin analogs, including potential anti-obesity therapies like cagrilintide, act on neurons in the brainstem dorsal vagal complex (DVC) that express calcitonin receptors (CALCR). These receptors, often combined with receptor activity-modifying proteins (RAMPs), mediate the suppression of food intake and body weight. To understand the molecular and neural mechanisms of cagrilintide action, we used single-nucleus RNA sequencing to define 89 cell populations across the rat, mouse, and non-human primate caudal brainstem. We then integrated spatial profiling to reveal neuron distribution in the rat DVC. Furthermore, we compared the acute and long-term transcriptional responses to cagrilintide across DVC neurons of rats, which exhibit strong cagrilintide responsiveness, and mice, which respond poorly to cagrilintide over the long term. We found that cagrilintide promoted long-term transcriptional changes, including increased prolactin releasing hormone (Prlh) expression, in the nucleus of the solitary tract (NTS) Calcr/Prlh cells in rats, but not in mice, suggesting the importance of NTS Calcr/Prlh cells for sustained weight loss. Indeed, activating rat area postrema Calcr cells briefly reduced food intake but failed to decrease food intake or body weight over the long term. Overall, these results not only provide a cross-species and spatial atlas of DVC cell populations but also define the molecular and neural mediators of acute and long-term cagrilintide action.

Male sex is a risk factor for progression of diabetic kidney disease, but the reasons for this predilection are unclear. Here, we demonstrate that cell sex and sex hormones alter the metabolic phenotype of human proximal tubular epithelial cells (PTECs). Male PTECs displayed increased glycolysis, mitochondrial respiration, oxidative stress, apoptosis, and high glucose-induced injury, compared to female PTECs. This phenotype was enhanced by dihydrotestosterone (DHT) and linked to increased mitochondrial utilization of glucose and glutamine. Studies in vivo pointed towards increased glutamine anaplerosis in diabetic male kidneys. Male sex was linked to increased levels of glutamate, TCA cycle, and glutathione cycle metabolites, in PTECs and in the blood metabolome of healthy youth and youth with type 2 diabetes. Conversely, female PTECs displayed increased levels of pyruvate, glutamyl-cysteine, cysteinylglycine, and a higher GSH/GSSG ratio than male PTECs, indicative of enhanced redox homeostasis. Finally, we identified transcriptional mechanisms that control kidney metabolism in a sex-specific fashion. While X-linked demethylase KDM6A facilitated metabolic homeostasis in female PTECs, transcription factor HNF4A mediated the deleterious effects of DHT in male PTECs. This work uncovers the role of sex in glucose/glutamine metabolism, that may explain the roots of sex dimorphism in the healthy and diabetic kidney.

The importance of NAD+ homeostasis for neuronal health has been emphasized by studies on nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2), a NAD+-synthesizing enzyme, and sterile alpha and TIR motif-containing protein 1 (SARM1), a NAD+ hydrolase. NMNAT2 declines caused by neurodegenerative insults activate SARM1 to degenerate axons. To elucidate the impact of the NMNAT2-SARM1 axis on brain energy metabolism, we employed multi-omics approaches to investigate the metabolic effects caused by neuronal NMNAT2 loss. The loss of NMNAT2 in glutamatergic neurons results in a striking metabolic shift in the cerebral cortex from glucose to lipid catabolism, reduced lipid abundance, and pronounced neurodegenerative phenotypes. Proteomic analysis found that neuronal NMNAT2 loss altered levels of glial enzymes central to glucose and lipid metabolism. Genetic deletion of SARM1 in NMNAT2-deficient mice restores lipid metabolism and mitigates neurodegeneration. Taken together, we show that neuronal NAD+ reduction leads to SARM1-dependent maladaptive adaptations in both neurons and glia.

AbstractsGestational diabetes mellitus (GDM) is a common metabolic complication of pregnancy that is paradoxically associated with both fetal overgrowth and fetal growth restriction (FGR). While maternal hyperglycemia is widely presumed to drive macrosomia through excessive nutrient supply, the mechanisms underlying FGR remain poorly understood. Here, using a mouse model that recapitulates the small-for-gestational-age (SGA) phenotype observed in human GDM pregnancies, we identify placental underdevelopment as a principal driver of FGR. Despite systemic nutrient abundance, hyperglycemic placentas exhibit reduced mass and an increased fetal-to-placental weight ratio, indicative of placental insufficiency. Mechanistically, maternal hyperglycemia induces anabolic metabolic rewiring while suppressing oxidative phosphorylation (OXPHOS), accompanied by upregulation and nuclear redistribution of ATP-citrate lyase (ACLY). ACLY converts glucose-derived carbon into acetyl-CoA in the cytosol and nucleus, thereby coupling glycolytic flux to lipid and hexosamine biosynthesis as well as to global histone hyperacetylation. This hyperacetylation-associated epigenetic reprogramming activates metabolic, innate immune, and inflammatory gene programs while repressing pro-proliferative and anti-apoptotic pathways. Consequently, placental growth is compromised despite nutrient excess. Importantly, activation of the ACLY-acetyl-CoA axis and global histone hyperacetylation is consistently observed in human GDM placentas across diverse birth outcomes, suggesting a conserved metabolic-epigenetic adaptation to maternal hyperglycemia. Together, these findings identify ACLY-dependent acetyl-CoA production as a central metabolic node linking maternal hyperglycemia to chromatin remodeling and placental development control, thereby reshaping fetal growth trajectories.

The activation of non-shivering thermogenesis (NST) in brown adipose tissue (BAT) by environmental cold challenge yields strong metabolic benefit in the face of diet-induced obesity (DIO). Yet, a critical barrier to leveraging brown fat NST for therapeutic use against metabolic disease is that BAT is silenced and inactive at physiological ambient temperature conditions in humans. The mechanisms that govern this silencing process remain poorly understood. Here, we identified a putative BAT-silencing factor, aquaporin-1 (AQP1), in brown fat from wild-type (WT) mice via proteomics analysis. We generated the first BAT-specific AQP1 knockout mice (AQP1-KO) and revealed that AQP1-KO could activate NST under BAT silencing environmental conditions and that the AQP1-KO mice were significantly protected against DIO and metabolic dysfunction compared to Flox controls. We found that AQP1-KO mice on high fat diet (HFD) had reduced weight gain through reductions in fat mass, improved glucose tolerance, and increased whole body energy expenditure compared to Flox control mice. Mechanistically, we show that AQP1 ablation in mice had upregulated gene expression related to the electron transport chain (ETC) and mitochondrial translation contributing to the activation of NST under BAT environmental silenced conditions. Significance StatementNovel strategies to combat obesity-associated metabolic dysfunction are urgently needed to curb the growing obesity epidemic. Investigation of brown adipose tissue (BAT) silencing mechanisms may reveal novel therapeutic targets that when ablated, can activate BAT to increase energy expenditure and protect subjects against the metabolic dysfunction associated with obesity. We have identified Aquaporin 1 (AQP1) as a putative BAT silencer regulatory factor and show through the generation of the first BAT-specific aquaporin-1 knockout (AQP1-KO) mouse that BAT can be activated under environmental silencing conditions. We further show that these mice are protected against diet-induced obesity, with improved glucose tolerance, and increased energy expenditure. These findings highlight AQP1 as a promising therapeutic target in the emerging research field of BAT silencers.

Mitochondria warrant cellular energy demands by generating energy equivalents in central carbon metabolism. They are also able to newly synthesize fatty acids via mitochondrial fatty acid synthesis (mtFAS), however, the role of mtFAS for systemic metabolism has been poorly investigated. Here we show that mitochondrial Trans-2-Enoyl-CoA Reductase (MECR), a key enzyme of mtFAS, critically regulates cellular and systemic glucose and lipid homeostasis. In mice, liver or adipose tissue-specific deletion of Mecr reduces the capacity for aerobic glycolytic catabolism and lipogenesis and causes severe mitochondrial as well as fatal parenchymal organ dysfunction. Mechanistically, mtFAS is essential for pyruvate dehydrogenase activity, resulting in low NAD(P)H synthesis and reduced non-mitochondrial lipogenesis. In different human mitochondriopathies we further identify a dysregulation of mtFAS-associated lipid species, thus linking inherited mitochondrial disease to mtFAS. In summary, we introduce mtFAS as an important player in metabolic health via facilitating cellular glycolysis-derived metabolite transformation ultimately linking mtFAS to mitochondrial function and diseases.

Microglia play essential roles in maintaining energy homeostasis, and their dysfunction contributes to metabolic disease. Although high-fat diet (HFD) exposure induces microglial activation, the underlying mechanisms remain poorly defined. Here, we identified a previously unrecognized role for THIK-1 channel in mediating glucose sensing of microglia in arcuate nucleus of the hypothalamus (ARH), during HFD-induced obesity. Pharmacological inhibition of THIK-1 channel with tetrapentylammonium (TPA) suppresses feeding and attenuates body-weight gain in diet induced obese mice. Mechanistically, inhibition of agouti-related peptide (AgRP) neurons is indispensable for TPA-induced hypophagia. Moreover, THIK-1 inhibition promotes microglial phagocytosis of perineuronal nets (PNNs), leading to reduced AgRP neuronal activity and feeding suppression. Together, these findings establish THIK-1 as a critical glucose sensor in hypothalamic microglia and uncover a microglia-dependent pathway through which overnutrition modulates AgRP neuronal activity via PNN remodeling to regulate energy balance, highlighting THIK-1 as a potential therapeutic target for treatment of diet-induced obesity.

Consumption of processed foods is associated with dementia, obesity, and other negative health outcomes. Sustained heat treatment, a common food processing approach to enhance flavor, induces the chemical Maillard reaction that promotes the formation of dietary advanced glycation end-products (AGEs). The neurocognitive impacts of consuming dietary AGEs are poorly understood. Here we modeled an AGE-rich diet through heat treatment fed to rats during adolescence, a critical period of neural development, to mechanistically evaluate the long-term impact of early life dietary AGEs on behavioral and neural processes. Consuming the AGE-rich diet impaired hippocampal-dependent memory function and altered the gut microbiome without inducing obesity or nonspecific behavioral deficits. AGE-induced memory deficits were coupled with impaired hippocampal glutamatergic synaptic neurotransmission and altered expression in the synapse-pruning complement system. Hippocampal synaptic deficits likely result from direct AGE-complement interactions, as our extended studies reveal competitive antagonist action of AGEs on complement receptors. Memory impairments were prevented by administration of the AGE-inhibitor, alagebrium, and by supplementation with an AGE-inhibiting bacterial taxon, Lactococcus lactis, which was depleted in the heat-treated diet. These findings reveal a functional connection between early life dietary AGEs, the microbiome, and memory impairments, thus illuminating mechanisms through which food processing negatively impacts neurocognition.

The neonatal gastrointestinal tract mediates nutrient absorption and the establishment of immune tolerance to commensal microbiota. In early life, lysosome-rich enterocytes (LREs) in the ileum are necessary for the intracellular digestion of maternal milk proteins. However, the molecular mechanisms sustaining their function remain incompletely characterized. Here, we demonstrate that LRE mitochondrial homeostasis and autophagic capacity are critical for efficient nutrient uptake and maintenance of their specialized identity, as disruption of either process leads to premature differentiation into post-weaning enterocytes (PECs) with diminished endolysosomal and metabolic activity. Transcriptomic profiling further revealed that neonatal LREs exhibit a distinctive antioxidant signature, which preserves redox balance and safeguards the expression of the transcriptional regulators MAFB and BLIMP1, both central repressors of the neonatal-to-adult metabolic transition. These findings establish the mitochondria-lysosome axis as a key determinant of LRE function and neonatal metabolic programming. They also provide a mechanistic framework for understanding how organelle dysfunction and redox imbalance may contribute to early-life malnutrition syndromes, such as Kwashiorkor, and suggest therapeutic strategies aimed at preserving mitochondrial and lysosomal integrity.

Changes in mitochondrial energy metabolism are thought to be central to the development of diabetic kidney disease (DKD); however, whether this response is explicitly driven by systemic glucose concentrations remains unknown. Here, we show that titrating blood glucose concentrations in vivo directly impacts mitochondrial morphology and bioenergetics and remodels the mitochondrial proteome in the kidney in early DKD. Mitoproteomic analysis revealed profound metabolic disturbances induced by severe hyperglycemia, including upregulation of enzymes involved in the TCA cycle and fatty acid metabolism, enhanced ketogenesis as well as dysregulation of the mitochondrial SLC25 carrier family. Untargeted metabolomics and lipidomics confirmed the enrichment of TCA cycle metabolites, an increase in triglyceride concentrations, and extensive and specific cardiolipin remodeling. Lowering blood glucose to moderate hyperglycemia stabilized all three omic landscapes, partially prevented changes in mitochondrial morphology and bioenergetics, and improved kidney injury. This study demonstrates altered substrate utilization and energy generation in the kidney early in diabetes, during moderate and severe hyperglycemia and provides new insights into kidney metabolism, which has implications for therapeutic strategies aiming at the reinvigoration of mitochondrial function and signaling in diabetes.

Despite the success of fructose as a low-cost food additive, recent epidemiological evidence suggests that high fructose consumption by pregnant mothers or during adolescence is associated with disrupted neurodevelopment1-7. An essential step in appropriate mammalian neurodevelopment is the synaptic pruning and elimination of newly-formed neurons by microglia, the central nervous systems (CNS) resident professional phagocyte8-10. Whether early life high fructose consumption affects microglia function and if this directly impacts neurodevelopment remains unknown. Here, we show that both offspring born to dams fed a high fructose diet and neonates exposed to high fructose exhibit decreased microglial density, increased uncleared apoptotic cells, and decreased synaptic pruning in vivo. Importantly, deletion of the high affinity fructose transporter SLC2A5 (GLUT5) in neonates completely reversed microglia dysfunction, suggesting that high fructose directly affects neonatal development. Mechanistically, we found that high fructose treatment of both mouse and human microglia suppresses synaptic pruning and phagocytosis capacity which is fully reversed in GLUT5-deficient microglia. Using a combination of in vivo and in vitro nuclear magnetic resonance- and mass spectrometry-based fructose tracing, we found that high fructose drives significant GLUT5-dependent fructose uptake and catabolism, rewiring microglia metabolism towards a hypo-phagocytic state. Importantly, mice exposed to high fructose as neonates exhibited cognitive defects and developed anxiety-like behavior which were rescued in GLUT5-deficient animals. Our findings provide a mechanistic explanation for the epidemiological observation that early life high fructose exposure is associated with increased prevalence of adolescent anxiety disorders.

Ergothioneine (EGT) is a diet-derived, atypical amino acid that accumulates to high levels in human tissues. Reduced EGT levels have been linked to age-related disorders, including neurodegenerative and cardiovascular diseases, while EGT supplementation is protective in a broad range of disease and aging models in mice. Despite these promising data, the direct and physiologically relevant molecular target of EGT has remained elusive. Here we use a systematic approach to identify how mitochondria remodel their metabolome in response to exercise training. From this data, we find that EGT accumulates in muscle mitochondria upon exercise training. Proteome-wide thermal stability studies identify 3-mercaptopyruvate sulfurtransferase (MPST) as a direct molecular target of EGT; EGT binds to and activates MPST, thereby boosting mitochondrial respiration and exercise training performance in mice. Together, these data identify the first physiologically relevant EGT target and establish the EGT-MPST axis as a molecular mechanism for regulating mitochondrial function and exercise performance.

Adipose tissue homeostasis plays a critical role in metabolic disease but the metabolic circuitry regulating adipose tissue dynamics remains unclear. In this study, polyamine metabolism emerges as an important regulator of adipose tissue pathophysiology. We identify AZIN2 (Antizyme inhibitor 2), a protein promoting polyamine synthesis and acetylation, as a major regulator of total acetyl-CoA in adipocyte progenitors (APs). AZIN2 deficient APs demonstrate increased H3K27 acetylation marks in genes related to lipid metabolism, cell cycle arrest and cellular senescence, and enhanced adipogenesis compared to wild-type counterparts. Upon high-fat diet (HFD)-induced obesity, global AZIN2 deficiency in mice provokes adipose tissue hypertrophy, AP senescence, lipid storage perturbations, inflammation and insulin resistance. IL4 promotes Azin2 expression in APs but not mature adipocytes due to diminished IL4 receptor expression in the latter. In human visceral and subcutaneous adipose tissue, AZIN2 expression positively correlates with expression of early progenitor markers and genes associated with protection against insulin resistance, while it negatively correlates with markers of lipogenesis. In sum, AZIN2-driven polyamine metabolism preserves adipose tissue health, a finding that could be therapeutically harnessed for the management of obesity-associated metabolic disease.

Methionine -an essential amino acid that has to be provided by nutrition- and its metabolite S-Adenosyl methionine (SAM) are indispensable for cell proliferation, stem cell maintenance and epigenetic regulation 1-5, three processes that are central to embryonic development 6. Previous studies using chronic dietary restriction of methyl donors prior to and during gestation indicated that methionine restriction (MR) is detrimental to the development or growth of the neocortex 7,8, however, the consequences of acute MR have not been extensively studied. Here, we designed a dietary MR regime coinciding with the neurogenic phases of neocortex development in the mouse. Our results indicate that dietary MR for 5 days leads to a severe reduction in neocortex growth and neuronal production. In comparison, growth of the liver and heart was unaffected, highlighting an organ-specific response to MR which was also observed at the cellular and molecular levels. Progenitor cohort labeling revealed a time-dependent sensitivity to MR and cell cycle analyses indicated that after 5 days of MR, progenitors are stalled in the S/G2 phases. Unexpectedly, neocortex growth reduction induced after 5 days of MR is completely rescued at birth when switching the dam back to control diet for the remaining of gestation, uncovering a mechanism of catch-up growth. Using multiplexed imaging we probed metabolic and epigenetic markers following MR and during catch-up growth and show that pyruvate metabolism is rewired in progenitors. Altogether, our data uncover a transient state of quiescence in G2/S which is metabolically distinct from G0 quiescence and associated with efficient catch-up growth. More globally, our study highlights both the extreme sensitivity of the developing neocortex to acute dietary changes and its remarkable plasticity.

Sympathetic activation during cold exposure increases adipocyte thermogenesis via expression of mitochondrial protein uncoupling protein 1 (UCP1)1. The propensity of adipocytes to express UCP1 is under a critical influence of the adipose microenvironment and varies among various fat depots2-7. Here we report that cold-induced adipocyte UCP1 expression in female mouse subcutaneous white adipose tissue (scWAT) is regulated by mammary gland ductal epithelial cells in the adipose niche. Single cell RNA-sequencing (scRNA-seq) show that under cold condition glandular alveolar and hormone-sensing luminal epithelium subtypes express transcripts that encode secretory factors involved in regulating adipocyte UCP1 expression. We term mammary duct secretory factors as "mammokines". Using whole-tissue immunofluorescence 3D visualization, we reveal previously undescribed sympathetic nerve-ductal points of contact and show that sympathetic nerve-activated mammary ducts limit adipocyte UCP1 expression via cold-induced mammokine production. Both in vivo and ex vivo ablation of mammary ductal epithelium enhances cold-induced scWAT adipocyte thermogenic gene program. The mammary duct network extends throughout most scWATs in female mice, which under cold exposure show markedly less UCP1 expression, fat oxidation, energy expenditure, and subcutaneous fat mass loss compared to male mice. These results show a previously uncharacterized role of sympathetic nerve-activated glandular epithelium in adipocyte thermogenesis. Overall, our findings suggest an evolutionary role of mammary duct luminal cells in defending glandular adiposity during cold exposure, highlight mammary gland epithelium as a highly active metabolic cell type, and implicate a broader role of mammokines in mammary gland physiology and systemic metabolism.