Cleavage stimulating factor 64 depletion mitigates cardiac fibrosis through alternative polyadenylation

Authors: NEUPANE, RAHUL - Houston Methodist Research Institute; YOUKER, KEITH - Houston Methodist Research Institute; YALAMANCHILI, HARI - Children'S Nutrition Research Center (CNRC); CIESLIK, KATARZYNA - Baylor College Of Medicine; KARMOUTY-QUINTANA, HARRY - University Of Texas Health Science Center; GUHA, ASHRITH - Houston Methodist Research Institute; THANDAVARAYAN, RAJARAJAN - Houston Methodist Research Institute

Submitted to: Biochemical and Biophysical Research Communications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/24/2022
Publication Date: 1/29/2022
Citation: Neupane, R., Youker, K., Yalamanchili, H.K., Cieslik, K.A., Karmouty-Quintana, H., Guha, A., Thandavarayan, R.A. 2022. Cleavage stimulating factor 64 depletion mitigates cardiac fibrosis through alternative polyadenylation. Biochemical and Biophysical Research Communications. 597:109-114. https://doi.org/10.1016/j.bbrc.2022.01.093.
DOI: https://doi.org/10.1016/j.bbrc.2022.01.093

Interpretive Summary: Cardiac fibrosis is a complex process characterized by excessive deposits of connective tissue in the heart, which makes the heart stiff, unable to function, and ultimately result in heart failure. Fibrosis does not have any cure and it is debated whether it can be reversed. We discovered a novel RNA regulatory mechanism – alternative polyadenylation (APA) that is playing a role in progression of cardiac fibrosis using tissue samples and derived cells from patients with end stage heart failure. We found that the dysregulation of APA enhances and stabilizes the proteins responsible for progressing fibrosis in heart failure patients and showed that this process is reversible when the APA is corrected. Hence, our finding suggests a new therapy for controlling and reversing fibrosis in heart failure.

Technical Abstract: Alternative polyadenylation (APA) regulates gene expression by cleavage and addition of poly(A) sequence at different polyadenylation sites (PAS) in 3'UTR, thus, generating transcript isoforms with different lengths. Cleavage stimulating factor 64 (CstF64) is an APA regulator which plays a role in PAS selection and determines the length of 3'UTR. CstF64 favors the use of proximal PAS, resulting in 3'UTR shortening, which enhances the protein expression by increasing the stability of the target genes. The aim of this study is to investigate the role of CstF64 in cardiac fibrosis, a key event leading to heart failure (HF). We determined the expression of CstF64, key profibrotic genes, and their 3'UTR changes by calculating distal PAS (dPAS) usage in left ventricular (LV) tissues and cardiac fibroblasts from HF patients. CstF64 was upregulated in HF LV tissues and cardiac fibroblasts along with increased deposition of fibrosis genes such as COL1A and FN1 and significant shortening in their 3'UTR. In addition, HF cardiac fibroblasts showed increased transforming growth factor receptor B1 (TGFBR1) expression consistent with significant shortening in 3'UTR of TGFBR1. Upon knockdown of CstF64 from HF fibroblasts, downregulation in pro-fibrotic genes corresponding to lengthening in their 3'UTR was observed. Our finding suggests an important role of CstF64 in myofibroblast activation and promotion of cardiac fibrosis during HF through APA. Therefore, targeting CstF64 mediated RNA processing approach in human HF could provide a new therapeutic treatment strategy for limiting fibrotic remodeling.