Enhancement of dynein-mediated autophagosome trafficking and autophagy maturation by ROS in mouse coronary arterial myocytes

Authors

  • Ming Xu,

    1. Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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    • Ming Xu and Xiao-Xue Li contributed equally to this work.
  • Xiao-Xue Li,

    1. Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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    • Ming Xu and Xiao-Xue Li contributed equally to this work.
  • Yang Chen,

    1. Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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  • Ashley L. Pitzer,

    1. Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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  • Yang Zhang,

    1. Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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  • Pin-Lan Li

    Corresponding author
    1. Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
    • Correspondence to: Pin-Lan LI, M.D., Ph.D.,

      Department of Pharmacology and Toxicology,

      Medical College of Virginia, Virginia Commonwealth University,

      1220 East Broad Street, P.O. Box 980613, Richmond,

      VA 23298, USA.

      Tel. 804 828-4793

      Fax: 804 828-2117

      E-mail: pli@vcu.edu

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Abstract

Dynein-mediated autophagosome (AP) trafficking was recently demonstrated to contribute to the formation of autophagolysosomes (APLs) and autophagic flux process in coronary arterial myocytes (CAMs). However, it remains unknown how the function of dynein as a motor protein for AP trafficking is regulated under physiological and pathological conditions. The present study tested whether the dynein-mediated autophagy maturation is regulated by a redox signalling associated with lysosomal Ca2+ release machinery. In primary cultures of CAMs, reactive oxygen species (ROS) including H2O2 and O2−. (generated by xanthine/xanthine oxidase) significantly increased dynein ATPase activity and AP movement, which were accompanied by increased lysosomal fusion with AP and APL formation. Inhibition of dynein activity by (erythro-9-(2-hydroxy-3-nonyl)adenine) (EHNA) or disruption of the dynein complex by dynamitin (DCTN2) overexpression blocked ROS-induced dynein activation, AP movement and APL formation, and resulted in an accumulation of AP along with a failed breakdown of AP. Antagonism of nicotinic acid adenine dinucleotide phosphate (NAADP)-mediated Ca2+ signalling with NED-19 and PPADS abolished ROS-enhanced lysosomal Ca2+ release and dynein activation in CAMs. In parallel, all these changes were also enhanced by overexpression of NADPH oxidase-1 (Nox1) gene in CAMs. Incubation with high glucose led to a marked O2−. production compared with normoglycaemic CAMs, while Nox1 inhibitor ML117 abrogated this effect. Moreover, ML117 and NED-19 and PPADS significantly suppressed dynein activity and APL formation caused by high glucose. Taken together, these data suggest that ROS function as important players to regulate dynein-dependent AP trafficking leading to efficient autophagic maturation in CAMs.

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