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American Heart Association

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Final ID: We068

TRAF6 Mediates TFEB Ubiquitination to Inhibit Cardiomyocyte Autophagy in Sepsis-Associated Cardiac Dysfunction

Abstract Body: Sepsis-associated cardiac dysfunction (SACD) is the predominant cause of death in patients with severe sepsis. Complex mechanisms have been proposed for SACD, including maladaptive inflammation and autophagy. However, studies in the past have emphasized these different manifestations underlying SACD as discrete processes and largely neglect their inherent connection. Herein using both in vivo and in vitro SACD models, we showed that the cardiomyocyte Toll-like receptor 4 (cTLR4) can serve as a key receptor mediating the interaction between the cardiomyocyte and macrophage under SACD-like conditions. The stress-induced secretome of macrophage caused activation of cTLR4 which intensified the impairment of autophagic flux in cardiomyocytes. The TNF receptor-associated factor 6 (TRAF6) was further identified as the primary downstream target which conferred the regulatory effects of TLR4 signaling on cardiac autophagy. Importantly, we found that cardiac targeted Traf6 gain-of function exacerbated, while cardiac targeted Traf6 loss-of function partially rescued, the cardiac dysfunction in a mice model of SACD. Mechanistically, TRAF6 functioned as a ubiquitin E3 ligase to facilitate the degradation of transcription factor EB (TFEB) via ubiquitination and subsequently led to the blockage of autophagic flux. Along the line, dynamics computational simulation combined with experimental validation revealed unique local electrostatic interactions between human TRAF6 and TFEB. Overall, our study provides novel mechanistic supports which link the macrophage-initiated inflammation and cardiomyocyte autophagy, demonstrates a previously undescribed role of cTLR4/TRAF6/TFEB signaling in fine-tuning cardiac autophagy, and highlights TRAF6 as a novel therapeutic gene target to develop autophagy-based therapeutics for SACD.
  • Wang, Xiaoping  ( Peking Union Medical College , Beijing , China )
  • Author Disclosures:
    Xiaoping Wang: DO NOT have relevant financial relationships
Meeting Info:

Basic Cardiovascular Sciences

2024

Chicago, Illinois

Session Info:

Poster Session and Reception 3

Wednesday, 07/24/2024 , 04:30PM - 07:00PM

Poster Session and Reception

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