Diabetes

Type 2 diabetes is a heterogeneous disease that can be subdivided based on beta-cell function and insulin sensitivity. We aimed to investigate the presence, incidence and progression of diabetic retinopathy (DR) according to subtypes of type 2 diabetes. In a national cohort, we identified three subtypes of type 2 diabetes which included classical, hyperinsulinemic and insulinopenic type 2 diabetes based on HOMA2 measurements. From the Danish Registry of Diabetic Retinopathy (DiaBase) we extracted information on level of DR...

Sodium-glucose co-transporter 2 (SGLT2) inhibitor, an efficacious anti-diabetic agent, which has cardiovascular and renal benefits, can promote pancreatic β-cell regeneration in type 2 diabetic mice. However, the underlying mechanism remains unclear. In this study, we aimed to use multi-omics to identify the mediators involved in β-cell regeneration induced by dapagliflozin. We showed that dapagliflozin lowered blood glucose level, upregulated plasma insulin level, and increased islet area in db/db mice...

African Americans (AAs) have been underrepresented in polygenic risk score (PRS) studies. Herein, we integrated genome-wide data from multiple observational studies on type 2 diabetes (T2D), encompassing a total of 101,987 AAs, to train and optimize an AA focused T2D PRS (PRSAA), using a Bayesian polygenic modeling method (PRS-CS). We further tested the score in three independent studies with a total of 7,275 AAs. We then compared the PRSAA to other published scores. Results show that a 1 standard deviation increase in the PRSAA was associated with 40%-60% increase in the odds of T2D (OR=1...

Heat shock protein 20 (HSP20) emerges as a novel regulator of autophagy in the heart. Nonetheless, the detailed function of HSP20 in liver and its effect on autophagy remain unknown. Here, we observed that HSP20 expression is increased in liver tissues from mice and patients with metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as nonalcoholic fatty liver disease (NAFLD). Liver-specific downregulation of HSP20 mitigates hepatic steatosis and insulin resistance in obese mice, while upregulating HSP20 promotes lipid deposition and hepatocyte cell death...

Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease. As many genes associate with DKD, multi-omics approaches were employed to narrow the list of functional genes, gene products and related pathways providing insights into the pathophysiological mechanisms of DKD. The Kidney Precision Medicine Project human kidney single-cell RNA-sequencing (scRNAseq) dataset and Mendeley Data on human kidney cortex biopsy proteomics were utilized. R package Seurat was used to analyze scRNAseq and subset proximal tubule cells...

NAFLD is considered as a risk factor for cardiovascular and cerebrovascular disease owing to its close association with coagulant disturbances. However, the precise biological functions and mechanisms that connect coagulation factors to NAFLD pathology remain inadequately understood. Herein, with unbiased bioinformatic analyses followed by functional test, we demonstrate that hepatic expression of coagulation factor FVII decreases in patients and mice with NAFLD/NASH. By employing adenovirus-mediated F7-knockdown and hepatocyte-specific F7-knockout mouse models, our mechanistic investigations unveil a non-coagulant function of hepatic FVII in mitigating lipid accumulation and lipotoxicity...

Beneficial effects of SGLT2 inhibitors on kidney function are well-known; however, their molecular mechanisms are not fully understood. We focused on 78 kDa glucose-regulated protein (GRP78) and its interaction with SGLT2 and Integrin ß1 beyond the chaperone property of GRP78. In STZinduced diabetic mouse kidneys, GRP78, SGLT2, and Integrin ß1 increased in the plasma membrane fraction, while they were suppressed by canagliflozin. The altered subcellular localization of GRP78/Integrin ß1 in STZ mice promoted epithelial mesenchymal transition (EMT) and fibrosis, which were mitigated by canagliflozin...

Increasing evidence implicates chronic inflammation as the main pathological cause of diabetic nephropathy (DN). Exploration of key targets in the inflammatory pathway may provide new treatment options for DN. Here, we aim to investigate the role of Src Homology 2 Containing Protein Tyrosine Phosphatase 2 (SHP2) in macrophages and its association with DN. The upregulated phosphorylation of SHP2 was detected in macrophages of both diabetic patients and mouse model. Using the macrophage-specific SHP2 knockout mice (SHP2-MKO) and SHP2fl/fl mice injected with streptozotocin (STZ), we showed that SHP2-MKO significantly attenuated renal dysfunction, collagen deposition, fibrosis, and inflammatory response in STZ-induced diabetic mice...

Insulin resistance and its linked health complications are increasing in prevalence. Recent work has caused the role of Tribbles2 (TRIB2) in metabolism and cellular signaling to be increasingly appreciated, but its role in the progression of insulin resistance has not been elucidated. Here, we explore the functions of TRIB2 in modulating insulin resistance and the mechanism involved in insulin resistance mice and palmitic acid (PA) treated HepG2 cells. We demonstrate that whole-body knockout and hepatic-specific TRIB2 deficiency protect against diet-induced insulin resistance, inflammation and ER stress...

Type 1 diabetes (T1D) is an autoimmune disease where pathogenic lymphocytes target autoantigens expressed in the pancreatic islets, leading to the destruction of insulin-producing β-cells. Zinc transporter 8 (ZnT8) is a major autoantigen abundantly present on the β-cell surface. This unique molecular target offers the potential to shield β-cells against autoimmune attacks in T1D. Our previous work showed that a monoclonal antibody (mAb43) against cell-surface ZnT8 can home in on the pancreatic islets and prevent autoantibodies from recognizing β-cells...

Reactive oxygen species (ROS) are formed by virtually all tissues. In normal concentrations they facilitate many physiologic activities, but in excess they cause oxidative stress and tissue damage. Local antioxidant enzyme synthesis in cells is regulated by the cytoplasmic KEAP-1/ Nrf2 complex, which is stimulated by ROS, to release Nrf2 for entry into the nucleus where it upregulates antioxidant gene expression. Major antioxidant enzymes include glutathione peroxidase (GPx), catalase (CAT), superoxide dismutases (SOD), hemoxygenases (HO), and peroxiredoxins (Prdx)...

Cardiovascular disease represents the leading cause of death in people with diabetes, most notably from macrovascular diseases such as myocardial infarction or heart failure. Diabetes also increases the risk of a specific form of cardiomyopathy referred to as diabetic cardiomyopathy (DbCM), originally defined as ventricular dysfunction in the absence of underlying coronary artery disease and/or hypertension. Herein, we provide an overview on the key mediators of DbCM, with an emphasis on the role for perturbations in cardiac substrate metabolism...

The β-cell plays a crucial role in the pathogenesis of type 1 diabetes, in part through the posttranslational modification of self-proteins by biochemical processes such as deamidation. These neoantigens are potential triggers for breaking immune tolerance. We report the detection by LC-MS/MS of 16 novel Gln and 27 novel Asn deamidations in 14 disease-related proteins within inflammatory cytokine-stressed human islets of Langerhans. T-cell clones responsive against one Gln and three Asn deamidated peptides could be isolated from peripheral blood of individuals with type 1 diabetes...

Type 1 diabetes is a chronic autoimmune disease in which destruction of pancreatic beta cells causes life-threatening metabolic dysregulation. Numerous approaches are envisioned for new therapies, but limitations of current clinical outcome measures are significant disincentives to development efforts. C-peptide, a direct byproduct of proinsulin processing, is a quantitative biomarker of beta cell function that is not cleared by the liver and can be measured in the peripheral blood. Studies of quantitative measures of beta cell function have established a predictive relationship between stimulated C-peptide as a measure of beta cell function and clinical benefits...

Familial partial lipodystrophy (FPLD) is a heterogenous group of syndromes associated with a high prevalence of cardiometabolic diseases. Prior work has proposed DEXA-derived fat mass ratio (FMR) - defined as trunk fat percentage (trunk fat %) divided by leg fat percentage (leg fat %) - as a biomarker of FPLD, but this metric has not previously been characterized in large cohort studies. We set out to (1) understand the cardiometabolic burden of individuals with high FMR in up to 40,796 participants in the UK Biobank and 9,408 participants in the Fenland study, (2) characterize the common variant genetic underpinnings of FMR, and (3) build and test a polygenic predictor for FMR...

Heterogeneous nuclear ribonucleoprotein A1 (HNRNPA1) is involved in lipid and glucose metabolism via mRNA processing. However, whether and how HNRNPA1 alters adipocyte function in obesity remain obscure. Here, we found that obese state downregulated HNRNPA1 expression in white adipose tissue (WAT). The depletion of adipocyte HNRNPA1 promoted markedly increased macrophage infiltration, proinflammatory and fibrosis genes expression in WAT of obese mice, eventually leading to exacerbated insulin sensitivity, glucose tolerance, and hepatic steatosis...

Bile acids (BAs) are pleiotropic regulators of metabolism. Elevated levels of hepatic and circulating BAs improve energy metabolism in peripheral organs, but the precise mechanisms underlying the metabolic benefits and harm still need to be fully understood. In the present study, we identified orosomucoid 2 (ORM2) as a liver-secreted hormone (i.e., hepatokine) induced by BAs and investigated its role in BA-induced metabolic improvements in mouse models of dietinduced obesity. Contrary to our expectation, under a high-fat diet (HFD), our Orm2 knockout (Orm2-KO) exhibited a lean phenotype compared to C57BL/6J control, partly due to the increased energy expenditure...

Diabetic peripheral neuropathy (DPN) is a highly prevalent chronic complication in type-2 diabetes mellitus (T2DM), for which no effective treatment is available. In this multi-center, randomized, double-blind, placebo-controlled phase 3 clinical trial in China, T2DM patients with DPN received acetyllevocarnitine hydrochloride (ALC, 1,500 mg/day, n = 231) or placebo (n = 227) for 24 weeks, during which anti-diabetic therapy was maintained. Significantly greater reduction in modified Toronto Clinical Neuropathy Score (mTCNS) as the primary endpoint occurred in the ALC group (-6...

Hybrid insulin peptides (HIPs) formed through covalent cross-linking of proinsulin fragments to secretory granule peptides are detectable within murine and human islets. The 2.5HIP (C-peptide-Chromogranin A (CgA) HIP), recognized by the diabetogenic BDC-2.5 clone, is a major autoantigen in the NOD mouse. However, the relevance of this epitope in human disease is currently unclear. A recent study probed T-cell reactivity toward HIPs in patients with type 1 diabetes, documenting responses in one third of the subjects and isolating several HIP-reactive T-cell clones...

Dipeptidyl peptidase (DPP)-4 and neprilysin (NEP) rapidly degrade glucagon-like peptide 1 (GLP-1) in mice. Commercially available sandwich ELISA kits may not accurately detect the degradation products, leading to potentially misleading results. We aimed to stabilize GLP-1 in mice allowing reliable measurement with sensitive commercially available ELISA kits. Non-anesthetized male C57Bl/6JRj mice were subjected to an oral glucose tolerance test (OGTT; 2 g/kg glucose), and plasma total and intact GLP-1 were measured (Mercodia and Alpco ELISA kits, respectively)...