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Latent‐HIV‐1 Exosome Blockade Mitophagy Flux in Human Brain Microvascular Endothelial Cells
Author(s) -
Chandra Partha K,
Rutkai Ibolya,
Kim Hogyoung,
Braun Stephen E,
AbdelMageed Asim B,
Mondal Debasis,
Busija David W
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.802.59
Subject(s) - mitophagy , autophagy , parkin , pink1 , mitochondrion , microbiology and biotechnology , autophagosome , microvesicles , chemistry , exosome , biology , medicine , biochemistry , parkinson's disease , apoptosis , microrna , disease , gene
Background Insufficient removal of dysfunctional mitochondria, due to a defective mitophagy pathway, leads to increased ROS, oxidative stress, and neuroinflammation which triggers the pathogenesis of various neurodegenerative diseases. HIV‐1‐associated neurocognitive disorders (HAND) is a common disease with variable reported prevalence in different populations (20– 69%). We investigated how exosomes from latent‐HIV‐1 infected cells impaired mitophagy flux in the human brain microvascular endothelial cells (HBMVEC). Methods Exosomes were isolated by ultracentrifugation from latent‐HIV‐1 infected T‐cells [exo‐J Lat(9.2)] and monocytes (exo‐U1) and characterized by the qNano‐IZON and NanoSight 300 systems by measuring the concentrations (3.2×10 12 particles/mL), particle diameter (Mean: 100.5±28.8 nm), and size‐distribution (Mode: 75.5±3.5 nm) of exosomes from J Lat(9.2). To determine whether exposure to exo‐J Lat(9.2) could induce mitophagy, HBMVECs were exposed to varying doses of HIV‐exosomes (10, 25, 50 and 100 μg/mL) for 24 and 48 h, after which the expression level of mitophagy markers PINK1, Parkin, and Drp1 were determined using western blotting. Carbonyl cyanide 4‐(trifluoromethoxy) phenylhydrazone (FCCP; 5 μM for 3 h), a known mitophagy inducer, was used as a positive control. Results Mitophagy is a two‐step process by which damaged mitochondria are first primed by PINK1/Parkin proteins and then eliminated via the autophagic machinery. We then examined the expression levels of autophagy (macroautophagy) proteins: the autophagosome initiation marker (Beclin 1), autophagosome formation marker (LC3B‐II), and autophagy degradation marker (SQSTM1 or p62) in HBMVECs exposed to latent‐HIV‐1‐exosomes. Interestingly, following exposure of HBMVECs to exo‐J Lat(9.2), the expression level of PINK1/Parkin proteins were upregulated in a dose dependent manner, with a concomitant increase in the formation of autophagosomes, shown by increased expression of Beclin 1 and LC3B‐II. FCCP treated cells showed decreased expression of p62 indicated by the active presence of mitophagy flux. Remarkably, cell exposure to HIV‐exosome resulted in increased expression of p62, indicating a possible blockage of the mitophagy flux, leading to the accumulation of mitophagosomes. Conclusions Our preliminary study indicated that latent‐HIV‐1 exosome increased mitochondrial damage via defective mitophagy. Support or Funding Information Grant Numbers: U54 GM104940, AHA 17SDG33410366, HL‐093554. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .