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American Heart Association

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Final ID: Or101

Phospho-Mimic Mutation in Beta Tubulin Suppresses Arrhythmias and Improves Cardiac Connexin 43 Localization in Duchenne Muscular Dystrophy Mice

Abstract Body: Duchenne Muscular Dystrophy (DMD) is a severe X-linked neuromuscular disorder, causing progressive muscle degeneration and premature death due to heart and skeletal muscle dysfunction. It is caused by mutations in the dmd gene, leading to the absence of dystrophin, a crucial protein for muscle integrity. There is no cure for DMD. Its associated dystrophic cardiomyopathy is the primary cause of mortality by age 20. Connexin-43 (Cx43) is a gap junction protein responsible for electrical signaling in the heart. Cx43 localizes at the intercalated disc of the cardiomyocyte (CM), forming an intercellular channel with adjacent CMs; In DMD, Cx43 hemichannel remodels to the lateral side of the cardiomyocyte. Our previous research indicated that phospho-mimic Cx43 carrying serine to glutamic acid substitutions at the triplet regulatory site S325, S328, S330 in mdx hearts suppressed Cx43 lateralization and improved cardiac rhythm. The phospho-mimic Cx43 also reduced pathological hyperdensity and transverse directionality of microtubules in mdx cardiomyocytes. Colchicine (Colch) treatment, known to inhibit microtubule polymerization, also improved cardiac rhythm and Cx43 localization in mdx mice. To phenocopy the effect observed with Colch, we generated a mouse model with a beta tubulin mutation at serine 172, which was replaced by glutamic acid (S172E). We found reduced arrhythmias and improved localization of Cx43 in mdx hearts carrying the S172E phospho-mimic mutant tubulin by electrocardiography and immunofluorescent staining, respectively. Moreover, the proteomics data showed that the level of phospho-Cx43 was also upregulated in mdx hearts with S172E tubulin mutation. Further investigation will explore how this mutation impacts protein regulation and electrophysiology, and elucidate its mechanism of action in microtubule polymerization. These studies investigate a regulatory link between microtubule dynamics and localization of Cx43, potentially suggesting a novel therapeutic target for DMD-associated cardiomyopathy.
  • Zhou, Delong  ( Rutgers School of Graduate Studies , Newark , New Jersey , United States )
  • Wehrens, Xander  ( BAYLOR COLLEGE OF MEDICINE , Houston , Texas , United States )
  • Lampe, Paul  ( Fred Hutchinson Cancer Research Cen , Seattle , Washington , United States )
  • Gourdie, Robert  ( Fralin Biomedical Research Inst. , Roanoke , Virginia , United States )
  • Xie, Lai-hua  ( RUTGERS-NEW JERSEY MEDICAL SCHOOL , Newark , New Jersey , United States )
  • Fraidenraich, Diego  ( RUTGERS - NJMS , Newark , New Jersey , United States )
  • Nouet, Julie  ( Rutgers University , Newark , New Jersey , United States )
  • Mesa, Elam  ( Rutgers School of Graduate Studies , Newark , New Jersey , United States )
  • Geukgeuzian, Geovanni  ( Rutgers School of Graduate Studies , Newark , New Jersey , United States )
  • Li, Hong  ( Rutgers-NJMS , Newark , New Jersey , United States )
  • Liu, Tong  ( Rutgers University , Newark , New Jersey , United States )
  • Yehia, Ghassan  ( Rutgers University , Newark , New Jersey , United States )
  • Romanienko, Peter  ( Rutgers , New Brunswick , New Jersey , United States )
  • Rodney, George  ( Baylor College of Medicine , Houston , Texas , United States )
  • Author Disclosures:
    Delong Zhou: DO NOT have relevant financial relationships | Xander Wehrens: DO NOT have relevant financial relationships | Paul Lampe: DO NOT have relevant financial relationships | Robert Gourdie: DO have relevant financial relationships ; Individual Stocks/Stock Options:The Tiny Cargo Company Inc:Active (exists now) ; Research Funding (PI or named investigator):NHBLI/NIH:Active (exists now) ; Individual Stocks/Stock Options:Xequel Bio Inc:Active (exists now) ; Executive Role:The Tiny Cargo Company Inc:Active (exists now) | Lai-Hua Xie: DO NOT have relevant financial relationships | Diego Fraidenraich: DO NOT have relevant financial relationships | Julie Nouet: No Answer | Elam Mesa: No Answer | Geovanni Geukgeuzian: No Answer | Hong Li: No Answer | Tong Liu: No Answer | Ghassan Yehia: No Answer | Peter Romanienko: DO NOT have relevant financial relationships | George Rodney: No Answer
Meeting Info:

Basic Cardiovascular Sciences

2024

Chicago, Illinois

Session Info:

Early Career Pre-Conference Session 1: Next Best Thing

Monday, 07/22/2024 , 09:15AM - 10:15AM

Early Career Session

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