Sodium-myoinositol cotransporter-1, SMIT1, mediates the production of reactive oxygen species induced by hyperglycemia in the heart

Circulating miRNAs as Putative Biomarkers of Exercise Adaptation in Endurance Horses

Endurance exercise induces metabolic adaptations and has recently been reported associated with the modulation of a particular class of small noncoding RNAs, microRNAs, that act as post-transcriptional regulators of gene expression. Released into body fluids, they termed circulating miRNAs, and they have been recognized as more effective and accurate biomarkers than classical serum markers. This study examined serum profile of miRNAs through massive parallel sequencing in response to prolonged endurance exercise in samples obtained from four competitive Arabian horses before and 2 h after the end of competition. MicroRNA identification, differential gene expression (DGE) analysis and a protein-protein interaction (PPI) network showing significantly enriched pathways of target gene clusters, were assessed and explored. Our results show modulation of more than 100 miRNAs probably arising from tissues involved in exercise responses and indicating the modulation of correlated processes as muscle remodeling, immune and inflammatory responses. Circulating miRNA high-throughput sequencing is a promising approach for sports medicine for the discovery of putative biomarkers for predicting risks related to prolonged activity and monitoring metabolic adaptations.

Role of SGLT1 in high glucose level-induced MMP-2 expression in human cardiac fibroblasts

Cardiac fibrosis is a major pathological manifestation of diabetic cardiomyopathy (DCM), which leads to cardiac remodeling, dilated cardiomyopathy and congestive heart failure. Human cardiac fibroblasts (HCF) constitute the predominant cell type in the heart and matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are also involved in cardiac fibrosis. However, it is unclear whether high glucose levels affect the expression of MMPs and TIMPs in HCF. Sodium‑glucose cotransporter (SGLT) inhibitors have been developed as therapeutic agents and the anti‑DCM effect of SGLT inhibitors has been demonstrated by previous studies. However, whether SLGT inhibitors protect the diabetic heart by directly inhibiting the SGLTs in HCF in addition to lowering the blood glucose levels, has not yet been determined. In the present study, increased MMP‑2 expression was noted in HCFs in response to high glucose levels, which may be reversed by phlorizin (inhibits both SGLT1 and SGLT2), but not dapagliflozin (inhibits SGLT2). In addition, SGLT1 was revealed to be present in the HCFs and high glucose level was demonstrated to increase SGLT1 expression, which may be attenuated by phlorizin. Therefore it was concluded that high glucose levels induced MMP‑2 expression in the HCFs, potentially by upregulating SGLT1. SGLT1 inhibition may be a novel strategy for the treatment of DCM.