Effect of tankyrase 1 on autophagy in the corpus cavernosum smooth muscle cells from ageing rats with erectile dysfunction and its potential mechanism

This study compared tankyrase 1 expression and autophagy quantity between erectile dysfunction (ED) and non-ED rats'' corpus cavernosum smooth muscle cells (CSMCs). This study aslo explored the effect and possible mechanism of tankyrase 1 on autophagy and cell proliferation in ageing ED rats'' CSMCs. The intracavernous pressure and mean systemic arterial pressure were measured to investigate erectile function so that eight 24-month-old ED and eight 8-month-old male Wistar rats were choosed respectively. The rat CSMCs were isolated and cultured by enzyme digestion, in which tankyrase 1 expression and autophagy quantity were compared. Tankyrase 1 overexpression was induced with plasmid transfection by Lipofectamine^™. The effect of tankyrase 1 overexpression on proliferation, autophagy and mTOR pathway in 24-month-old ED rats'' CSMCs was measured by the cell growth curve in MTT assay, cell cycle analysis in flow cytometry (FCM), key protein expression in Western blot, autophagy quantity in transmission electron microscopy, monodansylcadaverine staining and GFP-LC3 fluorescence. The primary CSMCs were confirmed by immunofluorescence, and the purity was 99.1% in FCM. Compared with that of 8-month-old rats, tankyrase 1 expression and autophagy quantity significantly decreased in 24-month-old ED rats'' primary CSMCs (P < 0.01). Tankyrase 1 overexpression significantly increased the growth rate (P < 0.05) and increased the S phase of cell cycle (P < 0.01). The autophagosome quantity was remarkably increased (P < 0.01), LC3-I/II and Beclin 1 were upregulated (P < 0.01 and P < 0.05), and p-p70S6K (Thr₃₈₉) was downregulated in 24-month-old ED rat CSMCs (P < 0.05). In conclusion, Tankyrase 1 and autophagy decrease in the CSMCs from aging rats with ED, and tankyrase 1 may have a positive effect on proliferation by enhancing autophagy and regulating the mTOR signalling pathway.