Project description:Type 2 diabetes is one of the most prevalent metabolic disorders. It is characterised by insulin resistance in peripheral tissues. Skeletal muscle is one of the tissues that affect by insulin resistance. Therefore, the study aims to identify differentially regulated genes in skeletal muscle of type 2 diabetes patients. Here, we obtained biopsies from the pectoralis major muscle and performed RNA sequencing to profile the gene expression patterns from four patients with diabetes and three healthy controls.
Project description:The current study aimed to address the hypothesis that programmed expression of key miRNAs in skeletal muscle mediates the development of insulin resistance, and consequently long-term health. We thus examined microRNA signatures in skeletal muscle of unmedicated newly diagnosed human pre-diabetics and type 2 diabetics. Skeletal muscle biopsies were obtained from the vastus lateralis from males with pre-diabetes (PD, n=5) or type 2 diabetes mellitus (T2DM, n=6) along with age and sex-matched healthy volunteers (H, n=5). Ramaciotti Centre for Genomics (UNSW, sydney, Australia)
Project description:Aging and type 2 diabetes mellitus (T2DM) are associated with impaired skeletal muscle function and degeneration of the skeletal muscle microenvironment. However, the origin and mechanisms underlying the degeneration are not well described in human skeletal muscle. Here we show that skeletal muscles of T2DM patients exhibit pathological degenerative remodeling of the extracellular matrix that was associated with a selective increase of a subpopulation of fibro-adipogenic progenitors (FAPs) marked by expression of THY1 (CD90).
Project description:Mechanistic insights into the molecular events by which exercise enhances the skeletal muscle phenotype are lacking, particularly in the context of type 2 diabetes. Here we unravel a fundamental role for exercise-responsive cytokines (exerkines) on skeletal muscle development and growth in individuals with normal glucose tolerance or type 2 diabetes. Acute exercise triggered an inflammatory response in skeletal muscle, concomitant with an infiltration of immune cells. These exercise effects were potentiated in type 2 diabetes. In response to contraction or hypoxia, cytokines were mainly produced by endothelial cells and macrophages. The chemokine CXCL12 was induced by hypoxia in endothelial cells, as well as by conditioned medium from contracted myotubes in macrophages. We found that CXCL12 was associated with skeletal muscle remodeling after exercise and differentiation of cultured muscle. Collectively, acute aerobic exercise mounts a non-canonical inflammatory response, with an atypical production of exerkines, which is potentiated in type 2 diabetes.
Project description:Type 2 diabetes mellitus (DM) is characterized by insulin resistance and pancreatic beta-cell dysfunction. In high-risk subjects, the earliest detectable abnormality is insulin resistance in skeletal muscle. Impaired insulin-mediated signaling, gene expression, and glycogen synthesis, and accumulation of intramyocellular triglycerides have all been linked with insulin resistance, but no specific defect responsible for insulin resistance and DM has been identified in humans. To identify genes potentially important in the pathogenesis of DM, we analyzed gene expression in skeletal muscle from healthy metabolically characterized nondiabetic (family history negative and positive for DM) and diabetic Mexican-American subjects. We demonstrate that insulin resistance and DM associate with reduced expression of multiple nuclear respiratory factor-1 (NRF-1)-dependent genes encoding key enzymes in oxidative metabolism and mitochondrial function. While NRF-1 expression is decreased only in diabetic subjects, expression of both PPARg coactivator 1-alpha and -beta (PGC1-a/PPARGC1, and PGC1-b/PERC), coactivators of NRF-1 and PPARg-dependent transcription, is decreased in both diabetic subjects and family history positive nondiabetic subjects. Decreased PGC1 expression may be responsible for decreased expression of NRFdependent genes, leading to the metabolic disturbances characteristic of insulin resistance and DM. Human muscle samples were obtained from five subjects with type 2 diabetes and ten subjects without diabetes, as well as 5 aliquots from a single subject without diabetes. The subjects without diabetes were further classified as family history positive (four subjects) or family history negative (six subjects).
Project description:Patients with hypertension alone, hypertension plus controlled diabetes and hypertension plus uncontrolled diabetes, and control patients without these conditions underwent coronary artery bypass grafting surgery. Skeletal muscle biopsy specimens were taken at the beginning ('pre-operative') and at the end ('post-operative') of the surgery.
Project description:Gene expression profiles of biopsy samples of skeletal muscle of three male patients of type 2 diabetes and three non-diabetic male patients were generated using Illumina HumanHT-12 v3 Expression BeadChip arrays. The primary indications of surgery were non-infective and non-malignant conditions, namely, cholelethiasis, hernia and trauma.