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FOXO1 promotes HIV latency by suppressing ER stress in T cells.

Nature microbiology (2020-06-17)
Albert Vallejo-Gracia, Irene P Chen, Rosalba Perrone, Emilie Besnard, Daniela Boehm, Emilie Battivelli, Tugsan Tezil, Karsten Krey, Kyle A Raymond, Philip A Hull, Marius Walter, Ireneusz Habrylo, Andrew Cruz, Steven Deeks, Satish Pillai, Eric Verdin, Melanie Ott
ABSTRACT

Quiescence is a hallmark of CD4+ T cells latently infected with human immunodeficiency virus 1 (HIV-1). While reversing this quiescence is an effective approach to reactivate latent HIV from T cells in culture, it can cause deleterious cytokine dysregulation in patients. As a key regulator of T-cell quiescence, FOXO1 promotes latency and suppresses productive HIV infection. We report that, in resting T cells, FOXO1 inhibition impaired autophagy and induced endoplasmic reticulum (ER) stress, thereby activating two associated transcription factors: activating transcription factor 4 (ATF4) and nuclear factor of activated T cells (NFAT). Both factors associate with HIV chromatin and are necessary for HIV reactivation. Indeed, inhibition of protein kinase R-like ER kinase, an ER stress sensor that can mediate the induction of ATF4, and calcineurin, a calcium-dependent regulator of NFAT, synergistically suppressed HIV reactivation induced by FOXO1 inhibition. Thus, our studies uncover a link of FOXO1, ER stress and HIV infection that could be therapeutically exploited to selectively reverse T-cell quiescence and reduce the size of the latent viral reservoir.

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