RhoA activation attenuates HSPA1A expression.

(A) Relative luciferase expression of a reporter construct driven by the SRE promoter (downstream target of RhoA/ROCK signaling) in HL-1 cardiomyocytes transfected with empty plasmid (pC, pcDNA3.1+), C3T exoenzyme plasmid (pC3T) or RhoA-WT encoding plasmid (pRhoA). (B) Relative luciferase expression of a reporter construct driven by the HSPA1A promoter in cardiomyocytes transfected with pC, pC3T or pRhoA. (C) Relative HSPA1A-luc expression in cardiomyocytes transfected with pC, pC3T or pRhoA and subjected to a HS (45°C, 10 min), white bars represent control non-HS, whereas black bars represent HS cells. (D) Top panel shows a representative Western blot with HSPA1A levels of cardiomyocytes transfected with pC, pC3T or pRhoA and subjected to a HS. Below, quantified data of HSPA1A/GAPDH levels for conditions as indicated. (E) Relative luciferase expression of a reporter construct driven by the HSPA1A promoter in cardiomyocytes transfected with empty plasmid pC, pC3T, pP190RhoGAP, pRhoA-n19, pRhoA or pRhoA-v14 without (E) and with (F) HS. (G) RhoA activation attenuates HSPA1A expression in human HEK-293 cells. Relative luciferase expression of a reporter construct driven by the HSPA1A promoter in HEK293 cells transfected with empty plasmid pC, pC3T, or pRhoA. *P<0.05, **P<0.01, ***P<0.001 compared to control pC and ^#P<0.05, ^##P<0.01 compared to pC or pC HS. White bar in panel (F) represents control non-HS cells, whereas black bars represent HS cells.