MKRN1 Ubiquitylates p21 to Protect against Intermittent Hypoxia-Induced Myocardial Apoptosis

Figure 5

The effect of MKRN1 overexpression in cardiomyocytes is reversed by p21 overexpression under IH conditions. (a, b) H9C2 cells were transfected with control siRNA (siControl) or two kinds of MKRN1-siRNAs (siMKRN1-1 and siMKRN1-2) before IH stimulation. Thereafter, the (a) protein and (b) mRNA expression levels of MKRN1 and p21 were detected using WB and qPCR, respectively (); versus the group; (c, d) H9C2 cells were transfected with the vector, MKRN1-overexpressing lentiviruses, and MKRN1-overexpressing lentiviruses combined with p21-overexpressing lentiviruses before IH stimulation. (c) Representative immunoblotting analysis and quantification of MKRN1, p21, Bcl-2, Bax, Bak, caspase-3, cleaved caspase-3 protein levels, and the Bax/Bcl-2 ratio () and GAPDH as an internal control; , versus the group, , versus the group, , and versus the group; (d) representative fluorescence image of DHE staining and quantification of fluorescence intensity (scale bar, 100 μm) (); , versus the group, , versus the group, and versus the group. indicates the independent sample number in each group.

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