Simvastatin Attenuates Expression of Cytokine-inducible Nitric-oxide Synthase in Embryonic Cardiac Myoblasts

Abstract

Cardiac stem cells or myoblasts are vulnerable to inflammatory stimulation in hearts with infarction or ischemic injury. Widely used for the prevention and treatment of atherosclerotic heart disease, the cholesterol-lowering drugs statins may exert anti-inflammatory effects. In this study, we examined the impact of inhibition of hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase with simvastatin on the expression of inducible nitric-oxide synthase (iNOS) in embryonic cardiac myoblasts stimulated with the proinflammatory cytokines, interleukin-1 or tumor necrosis factor. Treatment with simvastatin significantly reduced the levels of iNOS mRNA and protein in cytokine-treated rat H9c2 cardiac embryonic myoblasts. Addition of the HMG-CoA reductase product, Lmevalonate, and the by-product of cholesterol synthesis, geranylgeranyl pyrophosphate, could reverse the statin inhibitory effect on iNOS expression. Simvastatin treatment lowered the Rho GTPase activities, whereas the Rho-associated kinase inhibitor Y27632 partially blocked the statin inhibitory effect on nitrite production in the cytokine-treated H9c2 cells. Treatment with simvastatin led to inactivation of NF-B by elevation of the NF-B inhibitor IB and reduction of the NF-B nuclear contents in the cytokine-stimulated H9c2 cells. Hence, treatment with simvastatin can attenuate iNOS expression and NO synthesis in cytokine-stimulated embryonic cardiac myoblasts. The statin inhibitory effect may occur through isoprenoid-mediated intracellular signal transduction, which involves several key signal proteins, such as Rho kinase and IB/NF-B. These data suggest that statin therapy may protect the cardiac myocyte progenitors against the cytotoxicity of cytokine-induced high output of NO production in infarcted or ischemic hearts with inflammation.

Statins as antiinflammatory and immunomodulatory agents: A future in rheumatologic therapy?

“…Similar results were seen with atorvastatin in a rat spinal injury model (73). Simvastatin decreases iNOS induction in embryonic cardiac myoblasts stimulated with IL-1␤ or tumor necrosis factor ␣ (TNF␣), an effect that is reversed by GGPP and duplicated with a Rho kinase inhibitor (74). Lovastatin, atorvastatin, and fluvastatin decrease both LPS-and interferon-␥ (IFN␥)-stimulated iNOS expression in murine macrophages by reducing iNOS transcription, an effect that is reversed by mevalonate, GGPP, or FPP (75).…”

CD1d-Associated Expression of NF-κB and Cardiac Dysfunction in Diabetic and Obese Mice

“…Nuclear proteins from wild-type C57BL/6 and db/dbl C57BL/6 mice and from wild-type Balb/C and CDldknockout mice were extracted from snap-frozen hearts as previously described (14). Briefly, tissues were harvested and homogenized with an Ultra-Turrax T25-tissue homogenizer (Janke and Kunkel) in a low-salt solution (0.6% Nonidet P-40; 150mMNaCl; 10 mM HEPES, pH 7.9; 1 mMEDTA; 0.5 mM phenylmethylsulfonyl fluoride), and centrifuged for 30 seconds at 2,000 rpm.…”

Anti-inflammatory Effect of Pitavastatin on NF-.KAPPA.B Activated by TNF-.ALPHA. in Hepatocellular Carcinoma Cells

“…38) Other studies have demonstrated that statins may regulate cytokine-induced IL-6 level through different signal pathways that involve both Y27632-sensitive and -insensitive molecular signaling, in particular the NF-kB pathway. 25) Our results demonstrate that the effect of pitavastatin at a low dose appears to be specific to the inhibition of HMG-CoA reductase, as the addition of MEV abolishes the inhibitory effect of pitavastatin. Furthermore, the pitavastatin-reduced NF-kB activity is possibly independent of the Rho kinase pathway.…”

“…24) The Rho kinase inhibitor Y27632 specifically inactivates the p160 Rho-associated protein kinase p160ROCK, which is known to regulate NF-kB activity. 25) 636…”