Ribonucleic Acid Interference Knockdown of Interleukin 6 Attenuates Cold-Induced Hypertension

Abstract

Abstract-The purpose of this study was to determine the role of the proinflammatory cytokine interleukin (IL) 6 in cold-induced hypertension. Four groups of male Sprague-Dawley rats were used (6 rats per group). After blood pressure was stabilized, 3 groups received intravenous delivery of adenoassociated virus carrying IL-6 small hairpin RNA (shRNA), adenoassociated virus carrying scrambled shRNA, and PBS, respectively, before exposure to a cold environment (5°C). The last group received PBS and was kept at room temperature (25°C, warm) as a control. Adenoassociated virus delivery of IL-6 shRNA significantly attenuated cold-induced elevation of systolic blood pressure and kept it at the control level for Յ7 weeks (length of the study). Chronic exposure to cold upregulated IL-6 expression in aorta, heart, and kidneys and increased macrophage and T-cell infiltration in kidneys, suggesting that cold exposure increases inflammation. IL-6 shRNA delivery abolished the cold-induced upregulation of IL-6, indicating effective silence of IL-6. Interestingly, RNA interference knockdown of IL-6 prevented cold-induced inflammation, as evidenced by a complete inhibition of tumor necrosis factor-␣ expression and leukocyte infiltration by IL-6 shRNA. RNA interference knockdown of IL-6 significantly decreased the cold-induced increase in vascular superoxide production. It is noted that IL-6 shRNA abolished the cold-induced increase in collagen deposition in the heart, suggesting that inflammation is involved in cold-induced cardiac remodeling. Cold exposure caused glomerular collapses, which could be prevented by knockdown of IL-6, suggesting an important role of inflammation in cold-induced renal damage. In conclusion, cold exposure increased IL-6 expression and inflammation, which play critical roles in the pathogenesis of cold-induced hypertension and cardiac and renal damage. (Hypertension. 2010;55:1484-1491.)

AAV-Based RNAi Silencing of NADPH Oxidase gp91phox Attenuates Cold-Induced Cardiovascular Dysfunction

“…This sequence was designed to target on rat gp91 phox at 5'-CCA TCG AGC TTC AGA TGA A-3' (nucleotides 842-860). This gp91 phox -shRNA was then constructed into AAV-2 vector (Stratagene, La Jolla, CA) under the control of RNA polymerase III promoter U6 (AAV.U6-gp91-shRNA), as described in our recent studies (Wang et al, 2006;Crosswhite and Sun, 2010). AAV.U6-gp91-shRNA plasmid DNA was then packaged with pHelper and pAAV-RC to produce recombinant AAV-gp91-shRNA.…”

“…Following a 1-week recovery, three groups of animals were exposed to a moderate cold environment (5 -0.2°C) continuously, as we described recently (Crosswhite and Sun, 2010), whereas the remaining group was kept at room temperature (25 -2°C) and served as a control. The three cold-exposed groups of rats received intravenous (IV) delivery of AAV-gp91-shRNA (1.25 · 10 10 particles/rat, 0.5 mL), AAV-Control-shRNA (1.25 · 10 10 particles/rat, 0.5 mL), and phosphate-buffered solution (PBS; 0.5 mL/rat), respectively, 3 days before exposure to cold.…”

“…Therefore, we designed short hairpin RNA (shRNA) carried by adenoassociated virus serotype 2 (AAV-2) for in vivo specific inhibition of gp91 phox expression. Our recent studies showed that shRNA carried by the AAV-2 vector is an effective approach for long-term inhibition of protein expression in animal models (Wang et al, 2006;Crosswhite and Sun, 2010).…”

Antiaging Gene Klotho Regulates Adrenal CYP11B2 Expression and Aldosterone Synthesis

“…The VPR tail-cuff procedure can reliably monitor BP and is a common method for monitoring BP in our laboratory. 14,[43][44][45] …”

“…The semiquantitative analysis was done using the Image J software (NIH Freeware, Bethesda, MD) as described in our recent studies. 15,43,46 The numbers of CD4-, CD8-, and CD68-positive cells infiltrated in kidneys were counted in three random fields per section.…”