HIV-1 Vpr accessory protein has a negative impact on astrocityc telomerase activity

DIEGO OJEDA, JORGE QUARLERI, AND MAURICIO CAROBENE

Washington

Simposio; 12th International Symposium on NeuroVirology and 2013 Conference on HIV in the Nervous System; 2013

Background HIV-1 Infection leads to a wide spectrum of neurodegenerative diseases. Among central nervous system (CNS) cells, astrocytes have been shown to be susceptible to HIV-1 infection, although infection is nonproductive. Vpr is an HIV-1 accessory protein that negatively affects the highly controlled CNS compartment, inducing glial hyperactivation, astrocytic apoptosis, and secretion of neurotoxins that causes neuronal loss, which indicates that this protein may play an important role in HIV-1-associated neuropathogenesis. Telomerase is a cellular ribonucleoprotein complex key in controlling cellular senescence, and involved in inhibition of apoptosis, protection against oxidative stress, and improvement of DNA repair. Considering that HIV-1 has been shown to modify the cellular aging process by interfering with telomerase activity (TA), the aim of our study was to evaluate the impact of Vpr protein expression on TA in astrocytes. Methods Vpr coding sequence from HIV-1 NL4-3 strain was PCR-amplified and cloned into the pEGFP-C3 expression vector. U373 astrocytic cells were transfected with the pEGFP-Vpr vector, and TA was evaluated by real-time PCR (expressed as Relative Telomerase Activity, RTA), 48 h post-transfection. Untransfected and pEGFP-C3-transfected cells were used as controls. Transfection efficiency, expressed as percentage of GFP-positive cells, was measured by FACS. All experiments were carried-out by duplicate. Statistical differences were calculated by t-student test. Results Telomerase activity (RTA) was found to be significantly reduced in U373 astrocytic cells transfected with the HIV-1 Vpr-expression vector (25.7% RTA, p