Beta-Catenin Activation In Cardiac Fibroblasts Modulates The Immune Micro-Environment To Promote Fibrosis And Heart Failure Following Chronic Injury

Almost 6.5 million people in United States suffer from heart failure (HF). Diastolic HF following non-ischemic cardiac insult is a progressive condition with limited effective therapies underscoring the urgency to invest in identifying novel therapeutic targets for treatment. Reactive fibrosis in response to pathological stress is one of the major causes of diastolic HF. Emerging data suggest an association of systemic inflammation with reactive fibrosis and HF. Canonical Wnt/beta-catenin signaling has been linked to HF and fibrosis with limited understanding of the precise cellular and molecular mechanism. We utilized thoracic aortic constriction (TAC), a well-defined model of HF, to study Wnt signaling mediated reactive fibrosis. TAC was induced in a transgenic mouse model with stabilized beta-catenin (Wnt signaling) in fibroblasts (Bcat/Postn). Wnt activation following TAC resulted in increased maladaptive reactive fibrosis, HF marker ANP, and cardiac hypertrophy with preserved Ejection Fraction (pEF) suggesting Wnt-mediated progression of diastolic heart failure with pEF. TAC also resulted in increased macrophage activation and recruitment of CD8+ cytotoxic T-cells. In vitro co-culture of Wnt3a-overexpressing fibroblasts with activated myeloid cells promoted fibroblast proliferation and collagen synthesis. Therefore, we hypothesize that Wnt signaling activation promotes interstitial fibrosis via recruitment of specific inflammatory cells. Genomic analysis further supports this by demonstrating distinct chemokine gene expression patterns in fibroblasts resulting from Wnt activation in these injury models. Our future goal is to elucidate the role of Wnt signaling in modulating the fibroblast-immune cell crosstalk in modulating interstitial fibrosis induced diastolic HFpEF. Currently, there is no approved therapy to specifically target reactive fibrosis to avert diastolic dysfunction. Our study is aiming to identify targetable cellular and molecular players that improve, prevent or avert reactive fibrosis mediated HFpEF in order to reduce the incidence and severity of pathology resulting from HF.