Recent findings have broadened our understanding of the tripartite motif (TRIM) protein family, positioning these proteins as pivotal regulators of cellular metabolism and cell fate. Primarily functioning as versatile E3...Recent findings have broadened our understanding of the tripartite motif (TRIM) protein family, positioning these proteins as pivotal regulators of cellular metabolism and cell fate. Primarily functioning as versatile E3 ubiquitin ligases, TRIM proteins orchestrate key metabolic pathways-including glucose, lipid, and amino acid metabolism-through both ubiquitination-dependent and -independent mechanisms such as oligomerization and epigenetic modification. For example, TRIM38, TRIM11, and TRIM24 have been reported to modulate glycolytic flux and insulin signaling by targeting key glucose transporters and glycolytic enzymes, with effects on cancer metabolism and insulin responses in model systems. Similarly, TRIM21 and TRIM56 have been implicated in fatty acid synthesis, oxidation, and cholesterol balance, with potential relevance to fatty-liver conditions and atherosclerosis. Moreover, TRIM-mediated regulation of amino acid metabolism-particularly through pathways involving glutamine and branched-chain amino acids-plays a central role in tumor metabolic reprogramming and survival. Beyond enzymatic regulation, TRIM proteins exert non-canonical functions through epigenetic modulation and interactions with signaling networks. This review synthesizes current insights into the multifaceted roles of TRIM proteins in metabolic control and cell death, suggesting that ferroptosis may link TRIM proteins to lipid and amino acid metabolism, and highlights the connection between TRIM proteins and metabolic stress as a key area for future research.
Contemporary lifestyle modifications such as changes in nutritional and sleep/wake rhythms increase the risk of metabolic and inflammatory complications linked to obesity, including type 2 diabetes (T2D) and metabolic dy...Contemporary lifestyle modifications such as changes in nutritional and sleep/wake rhythms increase the risk of metabolic and inflammatory complications linked to obesity, including type 2 diabetes (T2D) and metabolic dysfunction-associated steatohepatitis (MASH). BMAL2 (Brain and Muscle ARNT Like Protein 2) is a transcription factor belonging to the circadian clock transcriptional feedback loop which synchronizes internal biological rhythms to environment. In humans, reduced expression in white adipose tissue (WAT) and specific polymorphisms of BMAL2 are associated with obesity and T2D. In this study we report that Bmal2 deletion in mice leads to increased body weight gain during diet-induced obesity. Loss of BMAL2 triggers the inflammatory response by increasing Tnfα expression and modifying adipocyte progenitor fate. This results in reduced lipid storage capacity within the WAT and increased ectopic storage in the liver. These functional and structural alterations culminate in the onset of hepatic steatosis and insulin resistance in liver and WAT. Overall, our investigations underscore the role of BMAL2 in the development and function of adipocytes, as well as in their inflammatory potential within the WAT. Our findings contribute to the understanding of the role of circadian clock genes in obesity and interconnected metabolic complications.
Kay M, Samuelsson AM, Bharucha N
… +10 more, Li X, Ramchandani R, Baum RE, Ruiz Arvizo D, Laguerre A, Lajevardi S, Kambhampati S, Metallo CM, Kapiloff MS, Karakikes I
Genetic dilated cardiomyopathy (DCM) is a leading cause of heart failure. However, disease-modifying therapies remain limited. Metabolic dysfunction has emerged as a key driver of DCM pathogenesis, and impaired serine bi...Genetic dilated cardiomyopathy (DCM) is a leading cause of heart failure. However, disease-modifying therapies remain limited. Metabolic dysfunction has emerged as a key driver of DCM pathogenesis, and impaired serine biosynthesis, catalyzed by the rate-limiting enzyme phosphoglycerate dehydrogenase (PHGDH), has recently been identified as a potential therapeutic target. Here, we evaluated the therapeutic potential of increasing serine biosynthesis through AAV9-mediated PHGDH gene augmentation in a transgenic TM54 mouse model of DCM with established pathology. Longitudinal echocardiography showed preserved systolic function and prevented ventricular dilatation in TM54 mice treated with AAV9-PHGDH compared to AAV9-GFP controls. Histological analysis revealed reduced myocardial fibrosis and cardiomyocyte hypertrophy in AAV9-PHGDH-treated TM54 hearts, indicating a reversal of pathological remodeling. Metabolic profiling, including targeted metabolomics and in vivo C-glucose tracing analysis, revealed that serine levels increased in hearts treated with AAV9-PHGDH, accompanied by decreases in glucose-derived pyruvate and lactate. At the same time, mitochondrial oxidative metabolism remained intact, indicating a shift of glycolytic carbon towards serine biosynthesis. Collectively, these findings show that enhancing cardiac serine synthesis through PHGDH gene augmentation therapy preserves contractile function and mitigates disease progression in vivo, suggesting a novel metabolic therapeutic strategy for DCM.
Lipid droplets (LDs) are lipid-rich organelles recognized as central players in lipid homeostasis, signaling, and inflammation. While their functions in inflammation are well-documented, the mechanisms of LDs in antibact...Lipid droplets (LDs) are lipid-rich organelles recognized as central players in lipid homeostasis, signaling, and inflammation. While their functions in inflammation are well-documented, the mechanisms of LDs in antibacterial immunity and infection resistance remain less understood. Our results show that E. coli-infection trigger immunometabolic reprogramming and LD accumulation in murine macrophages (BMDM). Moreover, purified LDs from LPS-stimulated and E. coli-infected macrophages exhibited direct E. coli anti-bacterial activity. Pharmacological inhibition or genetic knockdown of DGAT1, a key enzyme in triglyceride synthesis, reduced LD formation, bacterial clearance, and pro-inflammatory responses (nitric oxide, PGE, CCL2, IL-6). Notably, DGAT1 inhibition impaired the expression of IFN-β and interferon-stimulated genes (ISGs), including viperin, iNOS, cathelicidin and IGTP, in E. coli-infected macrophages. In a cecal-ligation and puncture model of sepsis in C57BL/6 mice, DGAT1 inhibition reduced sepsis-induced LD accumulation in peritoneal cells and decreased levels of IFN-β, CCL2, nitric oxide, and lipid mediators (PGE, LTB, and RvD1) in the peritoneum. Furthermore, DGAT1 inhibition accelerated sepsis-related mortality, coinciding with elevated bacterial loads in the peritoneum and bloodstream at 6- and 24-h post-sepsis. Our results demonstrate that LDs are critical regulators of innate immunity infection resistance, contributing to both bacterial clearance and the coordination of a protective proinflammatory response during sepsis through mechanisms dependent on DGAT-1 and Type I IFN.
E4BP4/NFIL3 (E4 promoter-binding protein 4 or nuclear factor interleukin-3-regulated protein), is well-established for its association with circadian rhythm regulation and immune function. Recent advances in research hav...E4BP4/NFIL3 (E4 promoter-binding protein 4 or nuclear factor interleukin-3-regulated protein), is well-established for its association with circadian rhythm regulation and immune function. Recent advances in research have revealed its emerging and indispensable role in metabolic homeostasis, positioning it at the crossroads of circadian biology, immune responses, and metabolic balance. This review summarizes three decades of research on E4BP4/NFIL3 and explores its structural basis and regulatory functions. We synthesized current insights into the regulatory pathways that govern E4BP4/NFIL3 and discuss its central role in various metabolic scenarios, emphasizing its emerging significance as a pivotal metabolic regulator. Finally, we identify critical, unresolved questions and propose future research directions to enhance our understanding of E4BP4/NFIL3's broader implications in metabolic health.
BACKGROUND AND AIMS: Insulin resistance is a key driver of metabolic disorders, yet its molecular mechanisms remain elusive. This study identifies 27-hydroxycholesterol (27HC), a cholesterol-derived metabolite, and inves...BACKGROUND AND AIMS: Insulin resistance is a key driver of metabolic disorders, yet its molecular mechanisms remain elusive. This study identifies 27-hydroxycholesterol (27HC), a cholesterol-derived metabolite, and investigates its role in insulin resistance. METHODS: Targeted metabolomics quantified absolute and relative levels of 27HC (27HC/cholesterol ratio) in patients, mice, and hepatocytes. Insulin resistant mouse models were established to characterize spatiotemporal dynamics of 27HC and related enzymes. Functional analyses assessed 27HC's effect on insulin signaling across multiple hepatocyte types. Transcriptomic analysis identified key effector pathways. Plasma membrane cholesterol accessibility was evaluated using biosensors and validated by cholesterol rescue. Membrane protein extraction, immunofluorescence, and flow cytometry were employed to assess the impact of 27HC on insulin receptor (IR) distribution and binding capacity. RESULTS: Elevated 27HC levels were observed in patients with metabolic dysfunction-associated steatotic liver disease (MASLD), obese and type 2 diabetic mice (T2DM), and PA-treated HepG2 and primary hepatocytes, correlating with impaired insulin sensitivity. CYP27A1 was identified as the key enzyme regulating liver 27HC levels. In vitro studies demonstrated that 27HC disrupts insulin signaling in HepG2, AML12, and primary hepatocytes, whereas CYP27A1 knockdown restored IR responsiveness. 27HC suppresses SREBP2-dependent cholesterol biosynthesis, depleting accessible cholesterol in the plasma membrane, triggering IR mislocalization and signal attenuation. Liver-specific CYP27A1 silencing in mice fed a high-fat diet improved systemic insulin sensitivity and restored metabolic homeostasis. CONCLUSION: Our findings establish 27HC as a key effector linking cholesterol metabolism to insulin resistance and propose CYP27A1 inhibition as a potential therapeutic strategy for insulin resistance.
AIMS/HYPOTHESIS: Nutritional disorders directly affect the endocrine pancreas, increasing the susceptibility to type 2 diabetes mellitus. However, the molecular mechanisms underlying these alterations remain unknown. Thi...AIMS/HYPOTHESIS: Nutritional disorders directly affect the endocrine pancreas, increasing the susceptibility to type 2 diabetes mellitus. However, the molecular mechanisms underlying these alterations remain unknown. This study aims to characterize the role of endoplasmic reticulum (ER)-mitochondria contact sites, known as mitochondrial-associated membranes (MAMs), in insulin secretion dysfunctions associated with undernutrition, obesity, and the double burden of malnutrition (DBM). METHODS: Rat pancreatic INS-1E β-cells were cultured in a medium without amino acids supplemented with 1 × (control) or 0.25 × (amino acid restriction) of an amino acid solution for 48 h, and then cells were exposed to a fatty acid mix for 48 h. Male C57BL/6 mice were fed a normoprotein diet (14 % protein) or protein-restricted diet (6 % protein) for 6 weeks and subsequently a high-fat diet (35 % kcal) for 12 weeks. ER-mitochondria interactions were evaluated by in situ proximity ligation assay and transmission electronic microscopy. RESULTS: Our findings indicate that protein restriction reduces ER-mitochondria contacts in pancreatic beta-cells, leading to decreased mitochondrial metabolism and glucose-stimulated insulin secretion (GSIS). In contrast, obesity increases ER-mitochondria contact points, mitochondrial metabolism, and GSIS in pancreatic beta-cells, without alterations in viability. DBM results in a significant increase in ER-mitochondria contacts, elevated mitochondrial calcium levels, increased production of reactive oxygen species, and cell death, collectively contributing to impaired GSIS response in the context of obesity. CONCLUSIONS/INTERPRETATION: These data indicates that MAMs play a crucial role in GSIS during nutritional disorders such as undernutrition, obesity, and DBM. Importantly, changes in MAMs precede GSIS impairment, therefore targeting these interactions might prevent further disruption in beta-cell function.
Giannakogeorgou A, Kahl S, Granata C
… +12 more, Heilmann G, Mastrototaro L, Dewidar B, Bobrov P, Esposito I, Yavas A, Trenkamp S, Granderath FA, Schlensak M, Mantzoros CS, Roden M, Schrauwen P
BACKGROUND AND PURPOSE: Preclinical studies reported elevated growth differentiation factor 15 (GDF15) when mitochondrial function is reduced. In humans, metabolic dysfunction-associated steatotic liver disease (MASLD) a...BACKGROUND AND PURPOSE: Preclinical studies reported elevated growth differentiation factor 15 (GDF15) when mitochondrial function is reduced. In humans, metabolic dysfunction-associated steatotic liver disease (MASLD) and steatohepatitis (MASH) exhibit different hepatic mitochondrial adaptation. We hypothesized that circulating GDF15 differently correlates with hepatic mitochondrial respiration in obesity and/or MASLD/MASH. METHODS: Humans without (n = 20) and with biopsy-confirmed MASLD (n = 20) or MASH (n = 20) underwent hyperinsulinemic-euglycemic clamps to assess whole-body (M-value) and adipose-tissue (insulin-induced NEFA suppression) insulin sensitivity. Fasting serum GDF15 and glucagon were quantified by ELISA. Mitochondrial respiration was measured in liver obtained during bariatric surgery by high-resolution respirometry. Associations were assessed with Spearman's nonparametric correlation. RESULTS: Serum GDF15 correlated negatively with M-value (r = -0.35, p = 0.017) and NEFA suppression (r = -0.29, p = 0.046), but not with hepatic mitochondrial respiration across the whole cohort. However, correlations were found upon stratification into groups based on the presence (n = 37, age: 41 ± 2y, BMI: 49 ± 1 kg/m) or absence of hepatic fibrosis (n = 23, 44 ± 2 years, BMI: 49 ± 1 kg/m). In persons without fibrosis, GDF15 correlated positively with fatty acid oxidation-linked (F; r = 0.35, p = 0.035) and maximal coupled (FNS; r = 0.42, p = 0.010) mitochondrial respiration. Conversely, GDF15 correlated negatively with hepatic FN in persons with fibrosis (r = -0.48, p = 0.022). CONCLUSIONS: In humans with obesity, serum GDF15 correlates positively with hepatic mitochondrial respiration in persons without, but negatively in persons with hepatic fibrosis. Future studies are needed to investigate whether and how GDF15 affects hepatic mitochondrial respiration in a fibrosis-dependent manner and/or, conversely, how fibrosis might modulate hepatic GDF15 secretion through altered mitochondrial function.
AIMS: SerpinA3N (Serpin peptidase inhibitor clade A member 3) is a serine protease inhibitor upregulated in the hypothalamus by leptin and obesity, yet its role in physiological regulation remains poorly understood. This...AIMS: SerpinA3N (Serpin peptidase inhibitor clade A member 3) is a serine protease inhibitor upregulated in the hypothalamus by leptin and obesity, yet its role in physiological regulation remains poorly understood. This study aims to elucidate the role of hypothalamic SerpinA3N in regulation of energy balance, glucose homeostasis, and autonomic and cardiovascular functions. METHODS AND RESULTS: Immunostaining revealed that SerpinA3N is primarily expressed in neurons, including those expressing the leptin receptor (LepRb). Targeted deletion of SerpinA3N in LepRb neurons reduced body weight and adiposity and improved insulin sensitivity in female mice. SerpinA3N deficiency also enhanced leptin sensitivity, evidenced by amplified leptin-induced anorexia, weight loss, and LepRb signaling in the hypothalamic arcuate nucleus. Upon exposure to an obesogenic diet, mice lacking SerpinA3N in LepRb neurons exhibited attenuated weight gain, hepatic lipid accumulation and microgliosis. Notably, SerpinA3N deletion in LepRb neurons impaired baroreflex sensitivity and elevated renal sympathetic nerve activity, with dietary obesity further exacerbating sympathetic tone. CONCLUSIONS: These findings identify neuronal SerpinA3N as a key regulator of energy balance, leptin and insulin sensitivity, and autonomic function.
Mezza T, Wewer Albrechtsen NJ, Di Giuseppe G
… +13 more, Ferraro PM, Soldovieri L, Ciccarelli G, Brunetti M, Quero G, Alfieri S, Nista EC, Gasbarrini A, Tondolo V, Mari A, Pontecorvi A, Giaccari A, Holst JJ
Chimeric antigen receptor (CAR) cell therapies have emerged as a groundbreaking approach in cancer treatment, offering new hope for patients with refractory tumors. Despite their success, the therapeutic efficacy of CAR...Chimeric antigen receptor (CAR) cell therapies have emerged as a groundbreaking approach in cancer treatment, offering new hope for patients with refractory tumors. Despite their success, the therapeutic efficacy of CAR cell therapies is often undermined by metabolic factors within the tumor microenvironment (TME), which impede CAR cell function and lead to treatment resistance. Current literature has not fully explored how these metabolic processes contribute to CAR cell therapy failure, particularly in the context of solid tumors, where the TME presents unique challenges. Addressing this gap is crucial for enhancing the effectiveness of CAR cell therapies across a broader range of cancers. Here, we review the latest research on the metabolic mechanisms that influence CAR cell therapy outcomes, from preclinical studies to clinical applications. We conducted a comprehensive analysis of studies from PubMed and Web of Science, focusing on how various metabolic processes-such as hypoxia, immune cytokine signaling, glycolysis, adenine metabolism, cellular senescence, lactic acid increment, and cholesterol metabolism-affect CAR cell functions, including cytotoxicity, proliferation, stemness, and activation. Additionally, we examine how interactions between CAR cells and other components of the TME, such as tumor cells, stromal cells, and the extracellular matrix, contribute to an immune-suppressive environment that diminishes CAR cell efficacy. We also discuss potential strategies for overcoming these metabolic barriers, including the development of CAR cells with enhanced metabolic regulation, gene expression modulation, and the combination of CAR cell therapy with existing pharmacological treatments. Our findings underscore the critical role of metabolism in shaping the anti-tumor efficacy of CAR cell therapies in both hematologic and solid tumors. By targeting metabolic pathways within the TME, it is possible to enhance CAR cell infiltration, function, and persistence, thereby overcoming resistance and improving therapeutic outcomes. This approach not only addresses a key limitation in current CAR cell therapies but also paves the way for more effective cancer treatments in the future.
BACKGROUND: The transition from acute kidney injury (AKI) to chronic kidney disease (CKD) is characterized by persistent renal fibrosis, in which abnormal lipid metabolism plays a crucial role. Syndecan-1 (SDC-1) has bee...BACKGROUND: The transition from acute kidney injury (AKI) to chronic kidney disease (CKD) is characterized by persistent renal fibrosis, in which abnormal lipid metabolism plays a crucial role. Syndecan-1 (SDC-1) has been implicated in various tissue remodeling processes; however, its role in lipid metabolism and fibrosis during the progression from AKI to CKD is not well understood. METHODS: This study used a murine model of unilateral ischemia-reperfusion-induced AKI-to-CKD progression for in vivo analysis and employed transforming growth factor-beta (TGF-β)-induced fibrosis in Human Kidney-2 cells and primary mouse tubular epithelial cells for in vitro studies. The tubule-specific knockout and overexpression of SDC-1 mice were utilized to investigate kidney fibrosis and lipid metabolism. RESULTS: Following unilateral ischemia-reperfusion and TGF-β stimulation, SDC-1 expression was significantly reduced, exacerbating renal fibrosis. Notably, SDC-1 deficiency led to lipid accumulation in the kidneys, while its overexpression alleviated lipid overload and improved metabolic parameters. Furthermore, SDC-1 played a crucial role in regulating fatty acid-binding protein 7 (FABP7), and its absence resulted in increased FABP7 levels. Inhibition of FABP7 not only reduced fibrosis but also restored carnitine palmitoyltransferase 1α expression, which suggests that the SDC-1/FABP7 axis is critical for maintaining lipid homeostasis and mitigating fibrosis in the kidney. CONCLUSION: These findings underscore the importance of SDC-1 in lipid metabolism and suggest that targeting lipid metabolic pathways may represent therapeutic strategies that can slow the progression of AKI to CKD.
Human diets play a crucial role in both human health and environmental sustainability. In 2019, the EAT-Lancet Commission on healthy diets from sustainable food systems introduced the EAT-Lancet planetary health diet, a...Human diets play a crucial role in both human health and environmental sustainability. In 2019, the EAT-Lancet Commission on healthy diets from sustainable food systems introduced the EAT-Lancet planetary health diet, a universal reference diet designed to promote human health while minimizing environmental degradation. It is a predominantly plant-based dietary pattern, rich in whole grains, vegetables, fruits, legumes, and nuts, while low in red meat and added sugars. In this mini-review, we summarize findings from prospective cohorts examining the EAT-Lancet diet in relation to mortality and cardiometabolic outcomes. Higher adherence to this diet was generally associated with lower risk of all-cause mortality, cardiovascular disease, and type 2 diabetes. However, the magnitude of associations varied depending on cohort characteristics, scoring systems, and methodological factors. In addition, adherence to the EAT-Lancet diet was generally low in the studies reviewed. These results suggest potential public health benefits of adopting the EAT-Lancet diet but also highlight the need for harmonized definitions and further research on underlying mechanisms.
Lipotoxic ceramides (CERs) are implicated in the development of insulin resistance, type 2 diabetes (T2D) and related complications. Exercise training improves insulin sensitivity, potentially via reducing intracellular...Lipotoxic ceramides (CERs) are implicated in the development of insulin resistance, type 2 diabetes (T2D) and related complications. Exercise training improves insulin sensitivity, potentially via reducing intracellular lipids or enhancing mitochondrial oxidation. Acid sphingomyelinase (ASM), which hydrolyzes sphingomyelin (SM) to CERs, is crucial for muscle repair and development, yet its role in insulin-resistant states and response to exercise remain unclear. We assessed ASM protein and activity, neutral sphingomyelinase (NSM) and sphingolipid species in skeletal muscle of insulin-sensitive (IS, n = 12), insulin-resistant (IR, n = 11) and T2D men (n = 20), before and after a 12-week high-intensity interval training (HIIT). Comprehensive phenotyping comprised hyperinsulinemic-euglycemic clamps, spiroergometry, targeted lipidomics and assessment of markers of mitochondrial quality control. ASM protein was lower at baseline and increased after HIIT only in T2D (p < 0.05), while ASM activity rose across all groups (IS p < 0.01; IR and T2D p < 0.001). HIIT also increased NSM protein in all groups (p < 0.05). Despite lower baseline SM levels in T2D, HIIT led to elevated CERs species in T2D (C16:0, C20:0, C22:0, C24:1, C24:0) and in IR (C16:0, C20:0) (all p < 0.05). Regression analysis suggested that changes in ASM protein and activity relate to changes in mitochondrial fusion and fission as well as AMP-activated protein kinase (AMPK)-mediated mitophagy. In conclusion, HIIT induces expression of both ASM and NSM and alters CER profiles in insulin-resistant skeletal muscle, independently of changes in insulin sensitivity. ASM could therefore rather contribute to exercise-induced mitochondrial remodeling than driving lipotoxicity, warranting further investigation of ASM as a potential target for exercise mimetic therapies.
Mund C, Sinha A, Aderhold A
… +27 more, Mateska I, Hagag E, Traikov S, Gercken B, Soto A, Pollock J, Arndt L, Wölk M, Werner N, Fodelianaki G, Subramanian P, Chung KJ, Grossklaus S, Langner M, Elgendy M, Grinenko T, Wielockx B, Dahl A, Gericke M, Blüher M, Coskun Ü, Voehringer D, Fedorova M, Peitzsch M, Murray PJ, Chavakis T, Alexaki VI
BACKGROUND AND AIMS: Adipose tissue function is integral to systemic metabolic homeostasis. Excessive adipose tissue growth is associated with development of chronic low-grade inflammation and whole body dysmetabolism. T...BACKGROUND AND AIMS: Adipose tissue function is integral to systemic metabolic homeostasis. Excessive adipose tissue growth is associated with development of chronic low-grade inflammation and whole body dysmetabolism. The cell metabolic pathways regulating adipose tissue growth and homeostasis are little understood. Here we studied the role of polyamine metabolism in adipose tissue (patho)physiology. METHODS: We generated mice with global and adipocyte progenitor (AP)-specific Antizyme inhibitor 2 (AZIN2) deficiency and performed diet-induced obesity studies. APs were isolated from the subcutaneous and gonadal adipose tissue of mice and cultured. RESULTS: Polyamine metabolism components, including AZIN2, were highly expressed in APs and their expression in the adipose tissue was downregulated with obesity. IL4 induced Azin2 expression in APs. AZIN2 facilitated polyamine synthesis and acetylation, and regulated total acetyl-CoA levels in APs. AZIN2 deficiency upregulated histone acetylation in genes related to lipid metabolism. Azin2 APs committed more efficiently to adipogenesis in vivo and in vitro, and were more prone to senescence compared to wild-type counterparts. Upon diet-induced obesity, global and AP-specific AZIN2 deficiency in mice provoked AP depletion, adipocyte hypertrophy, obesity, inflammation, glucose intolerance and insulin resistance. In human adipose tissue, AZIN2 expression strongly correlated with expression of progenitor markers. CONCLUSIONS: Altogether, we identified AZIN2 as a novel AP marker that regulates AP fate and preserves adipose tissue health.
Sarcopenia is a progressive musculoskeletal condition associated with aging, marked by a decline in muscle mass, strength, and performance. This condition not only compromises functional independence in older individuals...Sarcopenia is a progressive musculoskeletal condition associated with aging, marked by a decline in muscle mass, strength, and performance. This condition not only compromises functional independence in older individuals but also contributes to escalating healthcare and economic burdens. Although the underlying mechanisms are complex and multifaceted, recent discoveries have emphasized the regulatory influence of multiple forms of programmed cell death-including apoptosis, ferroptosis, necroptosis, and pyroptosis-on skeletal muscle degeneration. These cell death pathways contribute to key pathological features such as muscle fiber loss, proteostasis imbalance, neuromuscular dysfunction, mitochondrial deficits, and persistent inflammation. This review synthesizes current understanding of the molecular underpinnings of regulated cell death (RCD) in sarcopenia and discusses emerging therapeutic interventions aimed at modulating these pathways. These include pharmacological agents (e.g., ferroptosis inhibitors, polyphenols), structured exercise programs (notably resistance), targeted nutritional support (e.g., amino acids, vitamin D), cell-based therapies, and gene-targeted strategies. Despite growing evidence supporting RCD as a viable therapeutic target, the interplay among different cell death modalities and the translation of mechanistic insights into clinical practice remain insufficiently understood. Advancing sarcopenia treatment will require integrated multi-omics analyses, identification of predictive biomarkers, and rigorously designed clinical studies to support personalized and effective therapeutic approaches.
Exercise protects against several diseases including cardiometabolic disorders. However, the molecular mechanisms driving these adaptations remain incompletely defined. Endothelial nitric oxide synthase (eNOS), a key sou...Exercise protects against several diseases including cardiometabolic disorders. However, the molecular mechanisms driving these adaptations remain incompletely defined. Endothelial nitric oxide synthase (eNOS), a key source of nitric oxide (NO), is implicated in regulating glucose uptake, fatty acid metabolism, and mitochondrial remodeling in response to exercise. eNOS is expressed in both endothelial and non-endothelial cells and its effects on metabolism are multifaceted. Notably, eNOS is highly expressed in endothelial cells which are ubiquitous throughout all organ systems allowing them to closely integrate with surrounding cell types. This unique feature of the endothelium enables eNOS to influence both local microenvironments and signaling across organ systems. This review summarizes current findings on the role of eNOS-derived NO in exercise metabolism. Evidence suggests eNOS contributes to improved metabolic flexibility, enhanced mitochondrial function, and tissue crosstalk. However, data across experimental models remain mixed, with both supportive and conflicting results. Collectively, the literature indicates that eNOS plays a central, though context-dependent, role in facilitating exercise-induced metabolic benefits. Identifying the specific mechanisms and tissue contributions of eNOS activity remains an important area for future investigation, with potential relevance to metabolic disease prevention and treatment.
BACKGROUND: Gut microbiota and their metabolites play an essential role in type 2 diabetes (T2D). However, contributions of individual bacterial strains and their metabolites to T2D pathogenesis remain poorly understood....BACKGROUND: Gut microbiota and their metabolites play an essential role in type 2 diabetes (T2D). However, contributions of individual bacterial strains and their metabolites to T2D pathogenesis remain poorly understood. We investigated T2D regulation by Lactobacillus in various animal models to understand its therapeutic effects. METHODS AND RESULTS: We performed a case-control study of Chinese adults using metabolome profiling and identified an inverse correlation between l-glutamine and T2D serum concentrations. The glnA and GLUL genes encoding glutamine synthetase (GS) in L. plantarum 84-3 were also identified. L. plantarum 84-3 treatment significantly decreased serum inflammation and improved metabolic phenotypes in streptozotocin- or tetraoxypyrimidine-induced T2D rats, including blood glucose, glucose tolerance, insulin resistance, and lipids. We confirmed elevated serum l-glutamine levels in the L. plantarum 84-3 group. RNA sequencing analysis demonstrated that L. plantarum 84-3-derived l-glutamine is a vital bioactive molecule, improving glucose homeostasis by activating the liver AMPK/PPAR signaling pathway and ameliorating T2D. We conducted co-culture fermentation experiments in vitro and in vivo, and metagenomic and metabolomic analyses revealed that resistance starch combined with L. plantarum 84-3 significantly enriched of Lactobacillus abundance and increased the l-glutamine level, affecting of alanine, aspartate, and glutamate metabolism pathways, which was confirmed in vivo in rats. The reduced L. plantarum and l-glutamine levels were validated in a human T2D cohort. CONCLUSIONS: These findings revealed a novel therapeutic effect of L. plantarum in alleviating T2D-related glucose homeostasis by increasing circulating l-glutamine, which suggests viable preventive and therapeutic strategies for metabolic disorders.
BACKGROUND: The "thrifty genotype hypothesis" states that gene variants promoting efficient fat deposition may have been advantaged by natural selection to allow human survival during famine. Nowadays, such genes are ren...BACKGROUND: The "thrifty genotype hypothesis" states that gene variants promoting efficient fat deposition may have been advantaged by natural selection to allow human survival during famine. Nowadays, such genes are rendered detrimental by progress as they promote fat deposition in preparation for a famine that never comes, resulting in widespread obesity. Obesity is genetically heterogeneous, with a continuum between very rare syndromic, rare monogenic, and common polygenic forms of obesity. The identification of natural selection signatures has been largely restricted to polygenic obesity-susceptibility variants, and this approach has failed to validate the thrifty genotype hypothesis. However, polygenic variants may not be as relevant as monogenic mutations, characterized by strong phenotypic effects on body mass index variation and obesity risk, in detecting significant signatures of natural selection. METHODS: We investigated the patterns of natural selection of 65 syndromic and 8 monogenic obesity genes in the gnomAD multiethnic population (N = 807,162). RESULTS: Our data suggest that most dominant syndromic obesity genes display negative signatures of natural selection (i.e., deleterious alleles are selectively purged from the population). In contrast, monogenic obesity genes exhibit neither negative nor positive patterns of natural selection. Our findings do not support the thrifty genotype hypothesis for syndromic and monogenic hyperphagic obesity in 7 ethnic groups. CONCLUSION: Our work highlights the evolutionary mechanisms that have shaped the modern ethnic distribution of monogenic and syndromic obesity mutations, why some individuals are susceptible to obesity and have a profound impact on therapeutic strategies for managing chronic diseases.
Mitochondrial sirtuins, including SIRT3, SIRT4, and SIRT5, play pivotal roles in maintaining mitochondrial homeostasis by regulating oxidative phosphorylation, energy metabolism, and redox balance. Dysregulation of these...Mitochondrial sirtuins, including SIRT3, SIRT4, and SIRT5, play pivotal roles in maintaining mitochondrial homeostasis by regulating oxidative phosphorylation, energy metabolism, and redox balance. Dysregulation of these enzymes is closely associated with the pathogenesis of aging-related diseases such as neurodegenerative diseases, metabolic diseases, and cardiovascular diseases. SIRT3 has been the most extensively studied, demonstrating protective effects against oxidative stress and metabolic dysregulation. In contrast, while SIRT4 and SIRT5 are less characterized, they are critical for the regulation of insulin sensitivity, nitrogen metabolism, and mitochondrial function. This review focuses on the involvement of mitochondrial sirtuins in modulating cellular metabolism, redox balance, and mitochondrial homeostasis, highlighting their roles in the development and progression of aging-related diseases. Furthermore, we provide an overview of small-molecule modulators targeting mitochondrial sirtuins, which aim to restore cellular function, attenuate aging processes, and offer novel therapeutic strategies for treating aging-related diseases.