Research Paper Volume 16, Issue 13 pp 10749—10764

Cathepsin L induces cellular senescence by upregulating CUX1 and p16INK4a

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Figure 2. Downregulation of CTSL decreases the expression of CUX1 and p16INK4a, and inhibits cellular senescence in human ECs. (A, B) Western blot and qPCR analyses showing that siRNA-mediated CTSL knockdown (siCTSL) downregulates CUX1 and p16INK4a expression in human ECs. (C, D) siRNA-mediated CTSL knockdown (siCTSL) suppresses cellular senescence in human ECs as evidenced by SA-β-gal and γ-H2AX staining as well as by the expression of the SASP genes IL6, IL-1β, and ICAM-1. Quantitative plots for both β-gal+ cells (%) in SA-β-gal staining and γ-H2AX foci/cells (%) with γ-H2AX staining were shown on the right side of the panel C. DAPI staining visualizes the presence of nuclei as a control for the cells in this analysis. Data for Western blots represent three biologically independent samples (n = 3). Data for qPCR represent a combination of three (n = 3) biologically independent experiments. Data for both SA-β-gal staining and γ-H2AX staining represent three biologically independent samples (n = 3).