Effect of Losartan on Caveolin-1 and Hsp70 Expression in Vascular Smooth Muscle Cells (VSMC) From Spontaneously Hypertensive Rats

GIL LORENZO ANDREA; CACCIAMANI VALERIA; BENARDON MARIA EUGENIA; LOPEZ APPIOLAZA MARTÍN; GARRAMUÑO VALLÉS PATRICIA

La Punta, San Luis

Congreso; XXVII Reunión Científica Anual Sociedad de Biología de Cuyo; 2009

Sociedad de Biolog¨ªa de Cuyo

EFFECT OF LOSARTAN ON CAVEOLIN-1 AND Hsp70 EXPRESSION IN VASCULAR SMOOTH MUSCLE CELLS (VSMC) FROM SPONTANEOUSLY HYPERTENSIVE RATS Gil Lorenzo AF, Cacciamani V, Benardon ME, Lopez Apiazzola M, Vall¨¦s P. IMBECU, CONICET, FCM, UNCuyo, Mendoza, 5500. E-mail: gil.andrea@fcm.uncu.edu.ar Full expression of Angiotensin II signaling in VSMCs is dependent on the ROS derived from NADPH oxidase and the dynamic association of the Ang II (Ang II) type I receptor (AT1R) with caveolae/lipid rafts.The chaperone Hsp70 regulates a diverse set of signaling pathways through their interactions with proteins. We examined the AT1 receptor antagonist Losartan effect, on Caveolin- 1 and Hsp70 protein and its involvement on oxidative stress in VSMCs from SHR and WKY rats. VSMCs stimulated with Ang II (100 ¦Ìmol/L) for 15 min in the presence or absence of Losartan (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 1 and Hsp70 protein and its involvement on oxidative stress in VSMCs from SHR and WKY rats. VSMCs stimulated with Ang II (100 ¦Ìmol/L) for 15 min in the presence or absence of Losartan (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 1 and Hsp70 protein and its involvement on oxidative stress in VSMCs from SHR and WKY rats. VSMCs stimulated with Ang II (100 ¦Ìmol/L) for 15 min in the presence or absence of Losartan (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 caveolae/lipid rafts.The chaperone Hsp70 regulates a diverse set of signaling pathways through their interactions with proteins. We examined the AT1 receptor antagonist Losartan effect, on Caveolin- 1 and Hsp70 protein and its involvement on oxidative stress in VSMCs from SHR and WKY rats. VSMCs stimulated with Ang II (100 ¦Ìmol/L) for 15 min in the presence or absence of Losartan (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 1 and Hsp70 protein and its involvement on oxidative stress in VSMCs from SHR and WKY rats. VSMCs stimulated with Ang II (100 ¦Ìmol/L) for 15 min in the presence or absence of Losartan (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 1 and Hsp70 protein and its involvement on oxidative stress in VSMCs from SHR and WKY rats. VSMCs stimulated with Ang II (100 ¦Ìmol/L) for 15 min in the presence or absence of Losartan (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 caveolae/lipid rafts.The chaperone Hsp70 regulates a diverse set of signaling pathways through their interactions with proteins. We examined the AT1 receptor antagonist Losartan effect, on Caveolin- 1 and Hsp70 protein and its involvement on oxidative stress in VSMCs from SHR and WKY rats. VSMCs stimulated with Ang II (100 ¦Ìmol/L) for 15 min in the presence or absence of Losartan (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 1 and Hsp70 protein and its involvement on oxidative stress in VSMCs from SHR and WKY rats. VSMCs stimulated with Ang II (100 ¦Ìmol/L) for 15 min in the presence or absence of Losartan (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 (100 ¦Ìmol/L) added 30 min before Ang II stimulation were subjected to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreated with Losartan 100 ¦Ìmol/L and subsequently stimulated with Ang II (100 to RT-PCR and Western blot analysis. The exposure of SHR VSMCs to Ang II for 15 minutes downregulated membrane caveolin expression and overexpressed p22 and Nox4 NADHP oxidase isoforms, whereas Losartan increased Cav-1 expression, lightly increased Hsp70 and decreased p22 and Nox4 protein levels in SHR VSM cell membranes. VSMCs from WKY rats pretreat