HIV-1 disrupts mitochondrial dynamics: induces fission and mitophagy to attenuate apoptosis in astrocytes

DIEGO OJEDA; JORGE QUARLERI

Durban

Simposio; The IAS 2016 Towards an HIV Cure Symposium; 2016

International AIDS Society (IAS)

BackgroundThe presence of HIV-1 tissue reservoirs, located in the central nervous system, is the main support for HIV-1 chronic infection and the consequent avoidance to virus eradication in HIV-1-infected individuals.Given the diverse pathophysiological functions of mitochondria during viral infections, understanding the role of mitochondrial dynamics and mitophagy in HIV-infected astrocytes is highly warranted. The present study addressed these challenges and revealed new and opposing phenomena on HIV-infected. Here we demostrate that HIV-1 productive infection on astrocytes can induce aberrant mitochondrial dynamics by mitochondrial fission and subsequent complete mitophagy as a pivotal strategy to subvert imminent apoptosis due to increased mitochondrial injury.MethodsWe employed pNL43-DsRed/eGFP, a full-length infectious molecular clone of HIV-1 to infect U373 cells (human astrocytoma cells). It can be monitored on FACS (FACSCanto, BD Biosciences) through the fluorescent reporter gene expression and simultaneously evaluate intracellular ROS level (DCFDA), mitochondrial ROS production (MITOSox), mitochondrial transmembrane potential gradient ΔΨm (TMRM) and apoptosis (Caspase 3 & 7 and Annexin V). All measurements were made simultaneously 3 days post infection. Mitochondrial fragmentation, autophagy and mitophagy were measured in transfected cells overexpressing RFP-LC3 protein and later infected with HIV-1. Three days post-infection were stained with Mitotracker and evaluated by fluorescence microscopy. Statistical differences were calculated by Student t-test.ResultsROS production was significantly higher in U373 productively infected cells than in neighbor non-infected cells (82±5% vs. 15±3%; p