HIV-1 infection renders brain vascular pericytes susceptible to the extracellular glutamate

Abstract

Reduced pericytes coverage of endothelium in brain is one of the structural changes leading to breach of the Blood Brain Barrier during HIV infection. We previously showed in central memory T (TCM) cells that HIV latency increases cellular susceptibility to DNA damage. In this study we investigated susceptibility of primary brain pericytes infected with HIV-1 to DNA damage in response to glutamate and TNFα, both known to induce neuronal death during chronic inflammatory conditions. To infect pericytes, we used a single-cycle HIV-1 pseudotyped with VSV-G envelope glycoprotein and maintained the cultures until latency was established. Our data indicate that pericytes silence HIV-1 expression at similar rate compared to primary TCM cells. TNFα and IL-1β caused partial reactivation of the virus suggesting that progression of disease and neuroinflammation might facilitate virus reactivation from latency. Significant increases in the level of γH2AX, which reflect DNA damage, were observed in infected cultures exposed to TNFα and glutamate at day 2 post-infection. Glutamate, an excitatory neurologic stimuli, also caused increases in the γH2AX level in latently infected pericytes, whereas PARP and DNA-PK inhibitors caused reductions in cell population suggesting that HIV-1 latency affects repairs of single and double strand DNA breaks. For comparison, we also analyzed latently infected astrocytes and determined that DNA damage response in astrocytes is less affected by HIV-1. In conclusion, our results indicate that productive infection and HIV-1 latency in pericytes interferes with DNA damage response, rendering them vulnerable to the agents that are characteristic of chronic neuroinflammatory disease conditions.

Occludin, caveolin‐1, and Alix form a multi‐protein complex and regulate HIV‐1 infection of brain pericytes

“…Our group reported that brain pericytes express the main HIV‐1 receptor, CD4, HIV‐1 co‐receptors CCR5 and CXCR4, and that these cells are prone to HIV‐1 infection 19 . Several studies confirmed these results, identifying brain pericytes as an important player in HIV‐1 infection 11,20,22,23,44 . We recently proposed that pericytes might be HIV‐1 reservoir cells in the CNS, as they can alternate from productive HIV‐1 infection to latent steps of the viral cycle 22 .…”

“…19 Several studies confirmed these results, identifying brain pericytes as an important player in HIV-1 infection. 11,20,22,23,44 We recently proposed that pericytes might be HIV-1 reservoir cells in the CNS, as they can alternate from productive HIV-1 infection to latent steps of the viral cycle. 22 The importance of these findings stems from the fact that infection of pericytes may provide a gateway for HIV-1 to enter brain parenchyma.…”

Monocytes complexed to platelets differentiate into functionally deficient dendritic cells

“…Plasmid expressing vesicular stomatitis G protein (VSV‐G) was obtained from Dr. Dykes 46 . The virus stocks were generated as described previously with some modifications 47,48 . Briefly, human embryonic kidney cells, 293T, were cotransfected with 40 μg each of NL4‐3 vector and VSV‐G vector using polyethyleneimine.…”

“…46 The virus stocks were generated as described previously with some modifications. 47,48 Briefly, human embryonic kidney cells, 293T, were cotransfected with 40 g each of NL4-3 vector and VSV-G vector using polyethyleneimine. Virus supernatant was harvested after 72 h and concentrated using PEG6000 as described and resuspended in PBS.…”

The Paradox of HIV Blood–Brain Barrier Penetrance and Antiretroviral Drug Delivery Deficiencies

“…Several studies have shown that after an initial HIV infection, increased BBB permeability arises, contributing to significant neurological implications [ 17 , 18 ]. Part of this permeability change may be due to a reduction in pericyte coverage of the brain endothelium that may lead to monocyte neuro-infiltration, including trafficking of HIV-infected cells, and to elevated levels of proinflammatory cytokines [ 19 ]. Additionally, dysfunction of the BBB has been confirmed in the form of pericyte loss, contributing to the HIV-induced BBB dysregulation and associated comorbidities [ 20 ].…”