Tenascin-C drives cardiovascular dysfunction in a mouse model of diabetic cardiomyopathy

Background: Diabetic cardiomyopathy (DCM) is a complex condition linked to diabetes, characterized by cardiac and vascular dysfunction, frequently concomitant with heart failure with preserved ejection fraction. The extracellular matrix glycoprotein Tenascin-C (TNC) has been found to be upregulated under diabetic conditions. However, the potential contributory role of TNC in the progression of DCM remains largely unclear. This study was designed to elucidate the role of TNC in the pathogenesis of DCM. Methods: Diabetes was induced in adult male wild-type (WT) and TNC knockout (TNC-KO) mice, through the administration of streptozotocin (50 mg/kg) for five consecutive days. At 18 weeks cardiac and aortic vascular function was evaluated using echocardiography and wire myography. Myocardium and plasma samples were collected for biochemical, histological, and molecular analyses. Cardiomyocytes and cardiac fibroblasts were used to investigate the impact of diabetes on TNC expression, inflammation, myocardial stiffness and function. Additionally, transcriptomic analysis of cardiac tissue by RNA-sequencing was conducted. Plasma TNC levels were assessed by enzyme-linked immunosorbent assay in cohorts of heart failure patients and type 2 diabetes mellitus. Results: TNC-KO diabetic mice showed preserved left ventricular systolic and diastolic function, significantly reduced cardiac fibrosis and mitigated endothelial dysfunction compared to WT diabetic animals. Compared with cardiomyocytes of diabetic WT animals, cardiomyocytes of TNC-KO mice developed less stiffness (Fpassive). Additionally, exposing mouse cardiomyocytes and human cardiac fibroblasts to high glucose stress (30 mM) led to a significant increase in TNC expression. Conversely, recombinant human TNC promoted pro-inflammatory and oxidative stress markers in cardiomyocytes. The role of TNC in fibrosis and DCM was found to involve pathways related to p53 signaling and Serpin1k, Ccn1, Cpt1a, and Slc27a1, as identified by RNA sequencing analysis. Additionally, plasma TNC levels were significantly elevated in patients with heart failure, irrespective of diabetes status, compared to healthy individuals. Conclusions: Our findings indicate that in diabetes, TNC contributes to cardiac contractile dysfunction, myocardial fibrosis, oxidative stress, inflammation, and metabolic disturbances in diabetic mouse heart. These results implicate the potential of TNC inhibition as a novel therapeutic approach for treating DCM.