Fig. 7: AAV9-mediated cardiac-myocyte-specific knockdown of Igfbp7 rescued TAC-induced HF in mice.
From: Insulin-like growth factor-binding protein-7 (IGFBP7) links senescence to heart failure
AAV9-mediated shRNA knockdown of Igfbp7 in cardiac myocytes by echo-guided LV injection of AAV9-Igfbp7-shRNA in post-TAC mice hearts. a,b, At day 3 after surgery and injection, mCherry staining of heart sections tracked AAV9-mCherry-U6-mIgfbp7-shRNA to cardiomyocytes (a) (scale bars, 50 μm); meanwhile, qRT–PCR analysis showed that there is a significantly decreased Igfbp7 mRNA expression in the hearts of AAV9-mCherry-U6-mIgfbp7-shRNA-injected mice (n = 4) compared to AAV9-scrmb-shRNA-injected mouse hearts (n = 4) (b). c–g, Four weeks after TAC and injection, Igfbp7 knockdown attenuated TAC-induced HW/BW and LW/BW increase in AAV9-mCherry-U6-mIgfbp7-shRNA-injected mice (n = 11) compared to control shRNA-injected mice (n = 9) (c). d, Representative WGA staining of transverse heart cross-sections showing myocyte cross-sectional area, which demonstrates that Igfbp7 knockdown attenuated TAC-induced cardiac myocyte enlargement. Scale bars, 50 μm. e, Representative PSR staining of heart sections shows increased collagen deposition in control AAV9-scrmb-shRNA-injected TAC hearts, and this is much attenuated by Igfbp7 knockdown with AAV9-mCherry-U6-mIgfbp7-shRNA. Scale bars are 4 mm for top panels and 100 μm for bottom panels. f, Echocardiographic analysis shows improved cardiac function in AAV9-mCherry-U6-mIgfbp7-shRNA-injected mice (n = 11) compared to control shRNA-injected mice (n = 9). g, qRT–PCR revealed that there is a trend of decreased key senescence gene Trp53 and Cdkn1a expression in AAV9-mCherry-U6-mIgfbp7-shRNA-injected mice (n = 7) compared to control shRNA-injected mice (n = 9). In all panels, error bars represent s.e.m. Unpaired two-tailed t-tests were used to calculate P values.
