HIV-1 Tat Upregulates TREM1 Expression in Human Microglia

Because microglia are a reservoir for HIV and are resistant to the cytopathic effects of HIV infection, they are a roadblock for any HIV cure strategy. We have previously identified that triggering receptor expressed on myeloid cells 1 (TREM1) plays a key role in human macrophage resistance to HIV-mediated cytopathogenesis. In this article, we show that HIV-infected human microglia express increased levels of TREM1 and are resistant to HIV-induced apoptosis. Moreover, upon genetic inhibition of TREM1, HIV-infected microglia undergo cell death in the absence of increased viral or proinflammatory cytokine expression or the targeting of uninfected cells. We also show that the expression of TREM1 is mediated by HIV Tat through a TLR4, TICAM1, PG-endoperoxide synthase 2, PGE synthase, and PGE2-dependent manner. These findings highlight the potential of TREM1 as a therapeutic target to eradicate HIV-infected microglia without inducing a proinflammatory response.