RT Journal Article
SR Electronic
T1 Gain-of-function cardiomyopathic mutations in RBM20 rewire splicing regulation and re-distribute ribonucleoprotein aggregates within processing bodies
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.06.02.446820
DO 10.1101/2021.06.02.446820
A1 Aidan M. Fenix
A1 Yuichiro Miyaoka
A1 Alessandro Bertero
A1 Steven Blue
A1 Matthew J. Spindler
A1 Kenneth K. B. Tan
A1 Juan Perez-Bermejo
A1 Amanda H. Chan
A1 Steven J. Mayer
A1 Trieu Nguyen
A1 Caitlin R. Russell
A1 Paweena Lizarraga
A1 Annie Truong
A1 Po-Lin So
A1 Aishwarya Kulkarni
A1 Kashish Chetal
A1 Shashank Sathe
A1 Nathan J. Sniadecki
A1 Gene W. Yeo
A1 Charles E. Murry
A1 Bruce R. Conklin
A1 Nathan Salomonis
YR 2021
UL http://biorxiv.org/content/early/2021/06/03/2021.06.02.446820.abstract
AB RNA binding motif protein 20 (RBM20) is a key regulator of alternative splicing in the heart, and its mutation leads to malignant dilated cardiomyopathy (DCM). To understand the mechanism of RBM20-associated DCM, we engineered isogenic human induced pluripotent stem cells (iPSCs) with heterozygous or homozygous DCM-associated missense mutations in RBM20 (R636S) as well as RBM20 knockout (KO) iPSCs. iPSC-derived engineered heart tissues made from these cell lines recapitulated contractile dysfunction of RBM20-associated DCM and revealed greater dysfunction with missense mutations than KO. Analysis of RBM20 RNA binding by eCLIP revealed a gain-of-function preference of mutant RBM20 for 3′ UTR sequences that are shared with amyotrophic lateral sclerosis (ALS) and processing-body associated RNA binding proteins (FUS, DDX6). Deep RNA sequencing revealed that the RBM20 R636S mutant has unique gene, splicing, polyadenylation and circular RNA defects that differ from RBM20 KO, impacting distinct cardiac signaling pathways. Splicing defects specific to KO or R636S mutations were supported by data from R636S gene-edited pig hearts and eCLIP. Super-resolution microscopy verified that mutant RBM20 maintains limited nuclear localization potential; rather, the mutant protein associates with cytoplasmic processing bodies (DDX6) under basal conditions, and with stress granules (G3BP1) following acute stress. Taken together, our results highlight a novel pathogenic mechanism in cardiac disease through splicing-dependent and -independent pathways that are likely to mediate differential contractile phenotypes and stress-associated heart pathology.Competing Interest StatementN.J.S. is a scientific advisor to and has equity in Curi Bio, Inc. C.E.M. is a scientific founder and equity holder in Sana Biotechnology. The other authors declare no competing interests.