BACKGROUND: Continuous glucose monitoring (CGM) reveals heterogeneity of postprandial glucose responses (PPGR), a key target for optimizing glycemic control in type 2 diabetes (T2D). We analyzed PPGR patterns to identify...BACKGROUND: Continuous glucose monitoring (CGM) reveals heterogeneity of postprandial glucose responses (PPGR), a key target for optimizing glycemic control in type 2 diabetes (T2D). We analyzed PPGR patterns to identify subtypes reflecting pathophysiological differences. METHODS: Cross-sectional CGM data from 100 individuals with T2D were collected over 4 h following a standardized meal consumed twice. Dynamic PPGR features-glucose peak, incremental area under the curve (iAUC), rise and fall rates, final vs. fasting glucose-were used for K-Means clustering, with stability assessed using a Random Forest classifier trained on the first meal. In 50 participants, postprandial plasma glucose and insulin were measured, and clinical/metabolic parameters compared across clusters using one-way ANOVA. RESULTS: Three CGM-defined PPGR clusters were identified. Cluster 1 (n = 19) showed the highest peak and iAUC, with post-meal glucose remaining persistently above baseline. Cluster 2 (n = 56) and 3 (n = 25) had lower peaks and iAUCs, but Cluster 3 exhibited higher rise and fall rates than Cluster 2. Clusters did not differ in age, sex, BMI, or diabetes duration, but metformin use was lower in Cluster 3. Cluster 1 showed significantly lower insulin secretion (HOMA2-B%: 77.42 ± 25.64 vs. 104.96 ± 43.94) and higher insulin resistance (HOMA-IR: 7.94 ± 3.27 vs. 4.84 ± 2.78) than Cluster 3, with intermediate values for Cluster 2, confirmed by postprandial indices. Cluster 3 had a higher early insulin response than Cluster 1 and 2 (60-min insulinogenic index: 1.67 ± 1.07, 0.84 ± 0.31, 0.84 ± 0.58, respectively; p < 0.05). CONCLUSIONS: CGM-derived PPGR features could identify T2D subtypes with similar clinical profiles but distinct insulin secretion and sensitivity impairments, supporting targeted interventions.
Choline is an essential nutrient required for the synthesis of key molecules, such as phosphatidylcholine, sphingomyelin, acetylcholine, and S-adenosylmethionine. Choline metabolism encompasses two phases, namely the pos...Choline is an essential nutrient required for the synthesis of key molecules, such as phosphatidylcholine, sphingomyelin, acetylcholine, and S-adenosylmethionine. Choline metabolism encompasses two phases, namely the postprandial and postabsorptive states. The former enables the digestion, absorption, distribution, and storage of choline derivatives after a meal, while the latter allows the cellular utilization of choline and the mobilization of stored choline-containing molecules during fasting. Understanding choline metabolism is fundamental to the study of lipid disorders such as steatohepatitis or atherosclerosis, as well as neurodegenerative diseases, including Alzheimer's disease, and inflammatory signaling pathways. Members of the alkaline phosphatase (AP) superfamily are prominent contributors to extracellular choline metabolism. Within this family, several APs and ectonucleotide pyrophosphatases/phosphodiesterases (ENPP) members are required for physiological choline metabolism. While intestinal alkaline phosphatase (IAP) and alkaline sphingomyelinase/ENPP7 both participate in the digestion of choline-containing derivatives in the gut during the postprandial phase, circulating ENPP2, ENPP6, and tissue-nonspecific alkaline phosphatase (TNAP) act during the postabsorptive phase to generate choline. In this review we first provide a comprehensive overview of choline metabolism and then describe how APs and ENPPs have functionally and structurally co-evolved to catalyze sequential reactions within this metabolic pathway.
BACKGROUND AND AIMS: Age-related eye diseases (AREDs) share aging as a major risk factor, but the systemic molecular changes preceding disease onset remain incompletely understood. We aimed to define the shared and disea...BACKGROUND AND AIMS: Age-related eye diseases (AREDs) share aging as a major risk factor, but the systemic molecular changes preceding disease onset remain incompletely understood. We aimed to define the shared and disease-specific immunometabolic architecture of major AREDs and to examine how circulating molecular features relate to retinal phenotypes, pre-diagnostic patterns, and disease risk. METHODS: We performed a large-scale prospective multi-omics study in the UK Biobank integrating baseline plasma proteomics, metabolomics, retinal imaging-derived phenotypes, and longitudinal follow-up across five major AREDs: age-related macular degeneration, cataract, diabetic retinopathy, glaucoma, and retinal vascular occlusion. Cox regression, functional enrichment, protein-metabolite correlation, mediation analysis, trajectory analysis, and machine-learning models were applied. RESULTS: Proteome-wide analyses identified both shared and disease-specific circulating signatures, mainly involving immune, extracellular matrix, vascular, and stress-response pathways. Reconstructed population-level molecular patterns diverged from controls up to 15 years before diagnosis, with marked heterogeneity across diseases. Integration with retinal imaging linked immune- and matrix-related proteins to retinal neurodegenerative and microvascular phenotypes. Metabolite clustering and mediation analyses highlighted recurrent lipoprotein-related pathways, particularly HDL-related structure and composition, as cross-layer features associated with systemic protein signals, metabolic states, and disease risk. Combined proteomic-metabolomic models improved prediction of incident disease compared with protein-only models. CONCLUSIONS: Major AREDs share a systemic immunometabolic aging architecture while retaining substantial disease-specific molecular features. Circulating molecular alterations are detectable years before clinical onset and may support future biological stratification and risk prediction.
BACKGROUND: The progression of metabolic dysfunction-associated steatohepatitis (MASH) involves chronic, irreversible inflammatory responses linked to intracellular organelle dysfunction. While endoplasmic reticulum (ER)...BACKGROUND: The progression of metabolic dysfunction-associated steatohepatitis (MASH) involves chronic, irreversible inflammatory responses linked to intracellular organelle dysfunction. While endoplasmic reticulum (ER) stress and mitochondrial impairment are recognized as critical drivers, the precise molecular mechanisms governing inter-organelle communication in this disease context remain incompletely understood. AIM: This study aimed to investigate the role of the ER transmembrane protein SEC62 in MASH pathogenesis. Specifically, it sought to determine whether SEC62 expression is altered in MASH, define its functional impact on disease phenotypes, and elucidate the mechanistic pathway through which it regulates mitochondrial homeostasis and inflammation. RESULTS: SEC62 was upregulated in both human and mouse MASH livers. Hepatocyte-specific SEC62 overexpression worsened hepatic steatosis, inflammation, and mitochondrial damage, whereas SEC62 knockout ameliorated these features. Mechanistically, SEC62 interacted directly with ATAD3B at the mitochondria-associated membranes (MAMs) interface, leading to the significant downregulation of ATAD3B expression. This SEC62-ATAD3B axis resulted in defective mitophagy, increased mitochondrial reactive oxygen species (ROS) production, and amplified inflammatory responses. CONCLUSION: Our results demonstrate that SEC62 is a novel regulator of MAMs that drives MASH progression. By interacting with and suppressing ATAD3B, SEC62 disrupts mitochondrial quality control, leading to oxidative stress and inflammation. Together, these findings define a specific molecular mechanism of organelle interplay in MASH and position SEC62 as a potential therapeutic target for intervention.
BACKGROUND & AIMS: Metabolic dysfunction-associated steatohepatitis (MASH) is a progressive liver disease with limited therapeutic options, and the role of ferroptosis in its pathogenesis remains to be fully understood....BACKGROUND & AIMS: Metabolic dysfunction-associated steatohepatitis (MASH) is a progressive liver disease with limited therapeutic options, and the role of ferroptosis in its pathogenesis remains to be fully understood. In this study, we aimed to investigate the action of DNA damage-inducible transcript 4 (DDIT4) in the ferroptosis and regulation of MASH progression. METHODS: The Gene Expression Omnibus database of MASH mice models and ferroptosis database were used to identify crucial ferroptosis related genes in MASH. Hepatic DDIT4 expression was detected in MASH patients, mouse models and hepatocytes. The functional role of DDIT4 was assessed in different diet-induced MASH mice models with hepatocyte-specific DDIT4 overexpression or knockout. RNA-sequencing and immunoprecipitation-mass spectrometry (IP-MS) were performed to determine DDIT4 interacting proteins. Molecular docking was used to explore the potential compound targeting DDIT4. RESULTS: We have discovered significantly elevated DDIT4 levels in mice and patients with MASH, which were positively correlated with MASH severity. Hepatocyte-specific over-expression of DDIT4 aggravated ferroptosis and MASH progression, while DDIT4 deletion alleviated ferroptosis and MASH progression. Mechanistically, DDIT4 decreased glutathione peroxidase 4 (GPX4) expression in an mTORC1 dependent manner. Additionally, DDIT4 interacted with cytosolic GPX4 and inhibited TOM22-mediated mitochondrial translocation, resulting in mitochondrial GPX4 reduction and ferroptosis activation. Importantly, through molecular docking and surface plasmon resonance (SPR), we have identified quercetagetin, a natural flavonoid, as a potential DDIT4-targeting compound. Administration of quercetagetin alleviated hepatic steatosis, inflammation, and fibrosis in MASH mice. CONCLUSIONS: Our study establishes the DDIT4-GPX4-ferroptosis axis as a new regulatory node in MASH progression and highlights DDIT4 as a potential therapeutic target for MASH.
OBJECTIVE: The mechanisms by which skeletal muscle activity during exercise state modulates vascular function and atherosclerosis remain poorly understood. The aim of this study was to investigate the function of skeleta...OBJECTIVE: The mechanisms by which skeletal muscle activity during exercise state modulates vascular function and atherosclerosis remain poorly understood. The aim of this study was to investigate the function of skeletal muscle/endothelium axis and determine whether and how skeletal muscle-derived Meteorin-like (Metrnl), a myokine implicated in metabolism and inflammation, exerts endothelioprotective and anti-atherosclerotic effects. METHODS: In in vivo experiments, both loss- and gain-of-function strategies were used to evaluate the effect of skeletal muscle-derived Metrnl on vascular endothelial function and atherosclerosis. For loss-of-function, we generated skeletal muscle-targeted Metrnl-null mice on an apolipoprotein E gene knockout background. For gain-of-function, we restored skeletal muscle-derived Metrnl by systemic plasma administration and skeletal muscle-specific Metrnl overexpression mouse. In in vitro and ex-vivo experiments were conducted. RESULTS: The expression of Metrnl from skeletal muscle markedly increased in human and mice, thereby increased circulating Metrnl levels, mitigated inflammation responses and improved vascular endothelial function, consequently ameliorated atherosclerosis under chronic aerobic exercise condition. Importantly, the Metrnl loss-of-function experiments by skeletal muscle-specific Metrnl deficiency and neutralizing antibody against Metrnl exacerbated vascular inflammation, promoted leukocyte homing, and increased endothelial injury and atherosclerosis in mice. Conversely, the gain of skeletal muscle Metrnl function experiment by adeno-associated virus assay reversed these issues. In vitro and ex-vivo experiments exhibited that Metrnl decreased inflammation and endothelial damage. Mechanistically, the KIT/protein kinase B (Akt)/nuclear factor-κB signaling is essential for the benefits of Metrnl on endothelial cells. CONCLUSIONS: The findings concluded that skeletal muscle/artery axis exists and skeletal muscle modulates cardiovascular function via skeletal muscle-derived Metrnl under chronic aerobic exercise, and skeletal muscle-derived Metrnl may serve as a novel therapeutic target for metabolic disorders.
6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) is a bifunctional enzyme involved in the production and breakdown of fructose-2,6-bisphosphate (F-2,6-BP) and serves as a key regulator of glucose metabolism...6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) is a bifunctional enzyme involved in the production and breakdown of fructose-2,6-bisphosphate (F-2,6-BP) and serves as a key regulator of glucose metabolism. It is closely implicated in the progression of diabetes and its associated complications, including diabetic cardiomyopathy (DCM), diabetic kidney disease (DKD), and diabetic retinopathy (DR). PFKFB3 mediates diabetes-induced organ damage through its effects on immune-inflammatory responses, fibrosis, vascular dysfunction, as well as β-cells function and survival. In this review, we highlight the bidirectional regulatory role of PFKFB3 in diabetes and its complications and explore the therapeutic potential of PFKFB3 inhibitors for managing diabetes and its related complications.
The mammalian heart critically depends on oxidative metabolism of fatty acids, glucose, ketones, and amino acids to meet its extensive ATP demands. AKT/protein kinase B plays a central role in regulating cell growth and...The mammalian heart critically depends on oxidative metabolism of fatty acids, glucose, ketones, and amino acids to meet its extensive ATP demands. AKT/protein kinase B plays a central role in regulating cell growth and metabolism by coordinating an anabolic metabolism in response to insulin or IGF1, particularly by elevating glucose uptake and mTOR activity. Here, we investigated the effect of simultaneous deletion of the two major cardiac isoforms AKT1 and AKT2 on the function and metabolism of the adult mouse heart. Inducible cardiomyocyte specific AKT1 AKT2 double knockout mice developed a rapidly progressing and lethal heart failure with extensive cardiomyocyte atrophy. Metabolic analyses of substrate-specific respiration of mitochondria (respirometry) and of isolated cardiac tissue (Seahorse flux analysis) demonstrated that fatty acid metabolism was severely compromised, whereas glucose metabolism was less affected. Volume-specific in vivo NMR spectroscopy and CrCEST (Creatine chemical exchange saturation transfer) imaging revealed a drop of the cardiac phosphocreatine/ATP ratios from 2 to 1.5, indicating severe energetic depletion. Transcriptomic and proteomic studies showed that genes of the TCA cycle, β-oxidation, and oxidative phosphorylation were coordinately down-regulated. Moreover, AKT1/AKT2 deficient cardiomyocytes lost the ability to store fatty acids in lipid droplets (LDs) due to an early loss of perilipins and other proteins involved in LD generation and function. In conclusion, our data show that general, isoform-independent AKT signaling in cardiac myocytes is indispensable for preservation of cardiac fatty acid metabolism and energy supply.
OBJECTIVE: The basis for protein synthesis is the genetic code. Many of these proteins will affect intermediary metabolites by acting as enzymes, hormones, or by other actions. The aim of the present study was to assess...OBJECTIVE: The basis for protein synthesis is the genetic code. Many of these proteins will affect intermediary metabolites by acting as enzymes, hormones, or by other actions. The aim of the present study was to assess the relationships of a large number of proteins with endogenous metabolites. METHODS: Plasma protein levels were measured by the proximity extension assay (PEA) and metabolites by mass spectrometry. Cross-sectional relationships of 242 proteins and 790 metabolites were evaluated in the EpiHealth and POEM studies using a discovery/validation approach. Genetic instruments identified in UK Biobank for protein levels (n = 1621) and genetics for metabolite levels (n = 777) in SCAPIS and EpiHealth were employed for Mendelian randomization (MR) analysis regarding putative causal associations. RESULTS: In the observational analyses, 20% of the evaluated pairwise protein-metabolite associations were found significant in both the discovery and validation samples. We could however only find support for causal effects in the MR analysis for <0.1% of the pairwise associations, representing 326 unique proteins. The R for the relationship between the MR and observational estimates was only 0.05. 37 protein-metabolite relationships that were significant in a congruent fashion in both the observational and MR analyses were identified. A searchable online protein vs metabolite atlas was created for the scientific community to use these results. We also give some examples where metabolites were used to enhance protein findings in cardiovascular epidemiological research. CONCLUSION: This study provides a comprehensive assessment of a large number of protein- metabolite relationships using both observational and MR analyses, highlighting how these results could be used to enhance clinical research.
Inoue R, Tajima K, Okuyama T
… +17 more, Sakai C, Kanno T, Zou M, Kyohara M, Matsunaga K, Tsuno T, Luo J, Ishida E, Horike SI, Hirano T, Arakawa N, Kin T, Shapiro AMJ, Terauchi Y, Obinata H, Hirano H, Shirakawa J
Endoplasmic reticulum (ER) stress is a critical driver of pancreatic β-cell dysfunction and apoptosis. Although metformin, a drug used to treat type 2 diabetes, primarily decreases blood glucose levels by improving insul...Endoplasmic reticulum (ER) stress is a critical driver of pancreatic β-cell dysfunction and apoptosis. Although metformin, a drug used to treat type 2 diabetes, primarily decreases blood glucose levels by improving insulin sensitivity, its direct effects on β-cell survival remain unclear. Here, we investigated the effect of metformin on β-cell stress responses under ER stress conditions. Thapsigargin (Tg)-induced ER stress increased β-cell apoptosis in mouse islets, which was prevented by metformin in a dose-dependent manner. Treatment with metformin for 24 h suppressed the Tg-induced upregulation of unfolded protein response (UPR)-related genes, as confirmed by transcriptomic and pathway analyses. Quantitative proteomics revealed that Tg inhibited eIF2 signaling and protein translation, both of which were partially restored by metformin. Enrichment analysis further indicated the attenuation of apoptotic pathways in metformin-treated islets. Polysome profiling and puromycin incorporation assays demonstrated that metformin reduced protein translation independently of ER stress. Metformin promoted the dephosphorylation of 4E-BP1, a key initiator of cap-dependent protein translation that is activated by phosphorylation, and the antiapoptotic effect of metformin was abolished by 4E-BP1 knockdown in MIN6 cells. Phosphoproteomic analysis indicated that the activation of mTOR signaling, a kinase of 4E-BP1, in Tg-treated islets was mitigated by metformin. Taken together, these findings reveal a cytoprotective mechanism of metformin in β-cells, in which metformin suppresses ER stress-induced apoptosis through 4E-BP1-mediated inhibition of mRNA translation and modulation of mTOR signaling. This study highlights a β-cell-intrinsic action of metformin that may contribute to its long-term therapeutic benefits in diabetes management.
Diseases associated with obesity and metabolic dysregulation, such as diabetes and metabolic dysfunction-associated steatotic liver disease (MASLD) promote chronic low-grade inflammation, which in turn, may enhance the r...Diseases associated with obesity and metabolic dysregulation, such as diabetes and metabolic dysfunction-associated steatotic liver disease (MASLD) promote chronic low-grade inflammation, which in turn, may enhance the risk for cardiovascular disease. Emerging evidence in recent years suggests that chronicity of inflammation involves alterations in bone marrow homeostasis. Obesity-related inflammation and metabolic stress, including hyperglycemia or hyperlipidemia, may trigger rewiring of hematopoietic stem and progenitor cells (HSPCs) in the bone marrow, driving production of myeloid cells with heightened inflammatory capacity that in turn fuel and sustain chronic inflammation. This process is akin to trained immunity and may promote an inflammatory memory that links metabolic disorders to their cardiovascular complications. Clonal hematopoiesis of indeterminate potential (CHIP) is characterized by aging-related emergence of somatic mutations in hematopoietic cells that clonally expand and bear higher inflammatory potential. Importantly, a bidirectional link between CHIP and metabolic disorders as well as their cardiovascular sequelae emerges. Here, we review current concepts regarding the links between bone marrow biology and metabolic diseases and associated chronic inflammation.
Diabetic complications are major drivers of morbidity and mortality, leading to progressive cardiovascular, renal, retinal, and neurological damage. Early intervention is hindered by the lack of reliable biomarkers for p...Diabetic complications are major drivers of morbidity and mortality, leading to progressive cardiovascular, renal, retinal, and neurological damage. Early intervention is hindered by the lack of reliable biomarkers for prediction and disease staging. Advances in proteomics and metabolomics provide powerful tools to elucidate molecular mechanisms and identify clinically actionable signatures. This systematic review included 67 cohort and 41 cross-sectional studies published between 2012 and August 2025, comprising 73,580 participants. Most studies involved type 2 diabetes (T2D) populations (n = 71), followed by type 1 diabetes (T1D) (n = 16), as well as mixed T1D and T2D cohorts (n = 8). Most investigations analyzed serum or plasma, with additional studies examining urine and other matrices. Proteomic profiling was primarily conducted using mass spectrometry (MS)-based platforms, alongside several affinity-based technologies. Metabolomic analyses were largely MS-based, with a minority employing nuclear magnetic resonance spectroscopy. Overall, 275 metabolites and 363 proteins demonstrated predictive relevance. Pathway enrichment implicated lipoprotein metabolism in macrovascular complications, complement/coagulation and inflammatory signaling in nephropathy, VEGFA-VEGFR2 signaling in retinopathy, and receptor-mediated endocytosis in neuropathy, while amino acid metabolism was consistently disrupted. These molecular signatures show promise for early detection and risk stratification but require standardized prospective validation before clinical translation. PROSPERO registration number: CRD420250656551 Name of the registration: Metabolomics and proteomics-based biomarkers for chronic complications of diabetes: A comprehensive systematic review and meta-analysis. URL: https://www.crd.york.ac.uk/PROSPERO/view/CRD420250656551.
BACKGROUND: Identifying high-risk individuals for cardiovascular and all-cause mortality among individuals with cardiovascular-kidney-metabolic (CKM) syndrome stage 0-3 can guide the implementation of targeted interventi...BACKGROUND: Identifying high-risk individuals for cardiovascular and all-cause mortality among individuals with cardiovascular-kidney-metabolic (CKM) syndrome stage 0-3 can guide the implementation of targeted interventions. This study aimed to evaluate the predictive value of plasma proteins for future cardiovascular and all-cause mortality. METHODS: This study included 39,007 participants from the UK Biobank (UKB) with CKM stage 0-3 and available proteomic data. Associations between plasma proteins and future risks of cardiovascular and all-cause mortality were assessed using Cox proportional hazards models. Key proteins were identified through an ensemble machine learning approach integrating support vector machine (SVM), random forest (RF), and extreme gradient boosting (XGBoost) algorithms. Subsequently, Cox models were applied to evaluate the incremental predictive value of these key proteins and their ability to enhance risk stratification for mortality outcomes. Furthermore, temporal trajectories of protein levels were examined in the years preceding death. RESULTS: During a median follow-up of 15.2 years, 505 participants died from cardiovascular causes and 3368 from any cause. 56 and 269 out of 2911 plasma proteins were significantly associated with cardiovascular and all-cause mortality, respectively (Bonferroni-adjusted P < 0.05). Incorporating seven and eight key proteins into conventional model significantly improved long-term predictive performance (C-statistics: 0.812 versus 0.782 for cardiovascular mortality; 0.772 versus 0.739 for all-cause mortality; both P < 0.001), and also provided incremental predictive value for 5- and 10-year mortality risks. Notably, participants died during follow-up exhibited markedly elevated certain protein levels over a decade before deaths, with progressively increasing trajectories over time. Stratification based on optimal predicted risk thresholds further revealed distinct cumulative mortality risks across groups. CONCLUSIONS: In individuals with CKM stage 0-3, plasma proteins combined with traditional risk factors may predict future cardiovascular and all-cause mortality.