Withaferin-A Reduces Type I Collagen Expression In Vitro and Inhibits Development of Myocardial Fibrosis In Vivo

Abstract

Type I collagen is the most abundant protein in the human body. Its excessive synthesis results in fibrosis of various organs. Fibrosis is a major medical problem without an existing cure. Excessive synthesis of type I collagen in fibrosis is primarily due to stabilization of collagen mRNAs. We recently reported that intermediate filaments composed of vimentin regulate collagen synthesis by stabilizing collagen mRNAs. Vimentin is a primary target of Withaferin-A (WF-A). Therefore, we hypothesized that WF-A may reduce type I collagen production by disrupting vimentin filaments and decreasing the stability of collagen mRNAs. This study is to determine if WF-A exhibits anti-fibrotic properties in vitro and in vivo and to elucidate the molecular mechanisms of its action. In lung, skin and heart fibroblasts WF-A disrupted vimentin filaments at concentrations of 0.5–1.5 µM and reduced 3 fold the half-lives of collagen α1(I) and α2(I) mRNAs and protein expression. In addition, WF-A inhibited TGF-β1 induced phosphorylation of TGF-β1 receptor I, Smad3 phosphorylation and transcription of collagen genes. WF-A also inhibited in vitro activation of primary hepatic stellate cells and decreased their type I collagen expression. In mice, administration of 4 mg/kg WF-A daily for 2 weeks reduced isoproterenol-induced myocardial fibrosis by 50%. Our findings provide strong evidence that Withaferin-A could act as an anti-fibrotic compound against fibroproliferative diseases, including, but not limited to, cardiac interstitial fibrosis.

Withaferin A induces Nrf2-dependent protection against liver injury: Role of Keap1-independent mechanisms

“…While peak plasma concentration of WA after dietary exposure has not been assessed, Thaiparambil et al showed that peak plasma concentration of WA following 4 mg/kg ( i.p ) was 2 μM [54]. In addition to the well-established therapeutic and preventive role of WA in cancer, it has also been shown to have therapeutic effects against hepatotoxicity [55] [56], diabetes [57] and cardiac fibrosis [58]. Results from our hepatotoxicity experiments are in line with the protective and therapeutic phenotypes exhibited by WA in other models.…”

Osteoblastic alkaline phosphatase mRNA is stabilized by binding to vimentin intermediary filaments

“…It was shown that mRNAs may also associate with intermediate filaments, as ultrastructural in situ hybridization experiments disclosed that about 29% of total poly(A) + mRNAs are found close to or associated with vimentin filaments (Bassell et al, 1994). Challa and colleagues showed that vimentin filaments modulate post-transcriptional gene expression by association and stabilization of collagen mRNAs and thereby may play a role in development of tissue fibrosis (Challa and Stefanovic, 2011;Challa et al, 2012). It was also reported that vimentin interacts with the 5′-untranslated region of the mouse mu opoid receptor mRNA and serves as a post-transcriptional negative regulator of gene expression (Song et al, 2013).…”

Heart Regeneration with Engineered Myocardial Tissue

“…Targeting fibrosis may prevent progression of disease and be a complementary therapeutic for regeneration. For example, administration of withaferin-A, which binds and inhibits vimentin, reduced collagen mRNA half-life, collagen protein production, transcription of collagen genes, and interstitial fibrosis (59). Because engineered cardiac tissue will likely be delivered to a fibrotic environment, we must consider the role of fibroblasts when used as a cell source for tissue engineering (e.g., as a support cell for ECM maintenance) and take into account the host fibroblast and myofibroblast populations, which may act as barriers to or facilitators of integration of implanted engineered tissue.…”