Dysregulated Txnip-ROS-Wnt axis contributes to the impaired ischemic heart repair in diabetic mice.

ABSTRACT

Hyperglycemia-induced impairment of angiogenesis contributes to the unfavorable prognosis of myocardial ischemia in long-standing diabetes mellitus. The underlying mechanism remains largely unknown and therapeutic strategies thereby limited. In the present study, we investigated the possible involvement of thioredoxin-interacting protein (TXNIP) and Wnt/ß-catenin signaling in the context, and their possible relation was also explored. STZ induced diabetic mice were subjected to myocardial infarction (MI). Adenovirus expressing shTXNIP, shCtnnb1 (ß-catenin) driven by VE-Cadherin promoter was administered intramyocardially immediately after MI. Cardiac function, histology, and molecular analyses were performed at predetermined time points. Increased endothelial expression of TXNIP was found in diabetic hearts, which correlated well with reduced nuclear ß-catenin expression, insufficient angiogenesis, aggravated cardiac remodeling, and poor survival. Endothelial-specific knockdown of TXNIP significantly rescued ß-catenin activity, together with increased angiogenesis, preserved cardiac function, and improved survival rate. Moreover, additional knockdown of ß-catenin essentially reversed the beneficial effects of TXNIP downregulation. In vitro, high glucose treatment of human umbilical vein endothelial cells (HUVECs) increased TXNIP levels and ROS concentration, while it reduced ß-catenin activity. Silencing TXNIP or ROS scavenger restored the high glucose induced reduction of Wnt/ß-catenin activity in HUVECs. In addition, either reduction of TXNIP expression or supplementation of exogenous Wnt3a improved the HUVECs quantity and migration under high glucose conditions. Diabetes-induced increase of TXNIP expression in the endothelium contributes to impaired angiogenesis after MI, especially via the elevation of ROS and the impaired Wnt/ß-catenin signaling. Targeting TXNIP-ROS-Wnt is a promising strategy in improving the prognosis.