Figure 7.

Sirt1 is involved in Sirt1 antisense (AS) long noncoding RNA (lncRNA)–regulated cardiomyocyte (CM) proliferation. A, Ki67 immunofluorescence staining in isolated postnatal day 1 CMs transfected with si‐NC or si‐Sirt1 and quantification of ki67‐positive CMs (349 CMs from 4 mice in si‐NC group, 308 CMs from 4 mice in si‐Sirt1 group). Bar=50 μm. B, The protein levels of Sirt1 in isolated CMs transfected with adenovirus‐control (Ad‐NC), Ad–Sirt1 AS lncRNA (SAS), Ad‐SAS+si‐NC, or Ad‐SAS+si‐Sirt1 and quantitative analyses of protein intensity. β‐Actin was used as a loading control (n=3 mice per group). C, Ki67 immunofluorescence staining in CMs transfected with Ad‐NC, Ad‐SAS, Ad‐SAS+si‐NC, or Ad‐SAS+si‐Sirt1 and quantification of ki67‐positive CMs (391 CMs from 4 mice in Ad‐NC group, 399 CMs from 4 mice in Ad‐SAS group, 413 CMs from 4 mice in Ad‐SAS+si‐NC group, 347 CMs from 4 mice in Ad‐SAS+si‐Sirt1 group). Ki67‐positive CMs were indicated by arrows. Bar=50 μm. D, Western blotting analysis and quantitative analysis of Sirt1 protein levels in neonatal hearts injected with Ad‐NC, Ad‐SAS, Ad‐SAS+Ad‐si‐NC, or Ad‐SAS+Ad‐si‐Sirt1. β‐Actin was used as a loading control (n=5 mice per group). E, Immunofluorescence of ki67 in neonatal hearts injected with Ad‐NC, Ad‐SAS, Ad‐SAS+Ad‐si‐NC, or Ad‐SAS+Ad‐si‐Sirt1 and quantification of ki67‐positive CMs (1722 CMs from 5 mice in Ad‐NC group, 1733 CMs from 5 mice in Ad‐SAS group, 1769 CMs from 5 mice in Ad‐SAS+Ad‐si‐NC group, 1666 CMs from 5 mice in Ad‐SAS+Ad‐si‐Sirt1 group). Ki67‐positive CMs were indicated by arrows. Bar=50 μm. F, The schematic model of Sirt1 AS lncRNA interacted and stabilized Sirt1, thereby regulating CM proliferation and cardiac regeneration after myocardial infarction. Statistical significance was calculated using 2‐tailed unpaired Student t test in A and 1‐way ANOVA followed by least significant difference post hoc test in B through E. Data represent mean±SEM. *P<0.05.