Abstract
The population of HIV reservoir in infected person is very small, but extremely long-lived and is a major obstacle for an HIV cure. We previously showed that cells with established HIV latency have deficiencies in DNA damage response (DDR). Here, we investigated ability of HIV-1 to interfere with telomere maintenance, and the effects of targeting telomeres on latently infected cells. Our results show that telomeres are elongated in cultured primary memory CD4 + T cells (TCM) after HIV-1 infection and when virus latency is established. Similarly, much longer telomeres were found in several Jurkat-derived latently infected cell lines, indicating that virus stimulates telomere elongation. Exposing primary CD4+ TCM cells to BRACO19, an agent targeting telomeres, resulted in a higher rate of apoptosis for infected cultures at day 3 post-infection, during HIV-1 latency and for PMA-stimulated cultures with low level of HIV-1 reactivation. Importantly, BRACO19 induced apoptosis in infected cells with potency similar to etoposide and camptothecin, whereas uninfected cells were less affected by BRACO19. We also determined that apoptosis induced by BRACO19 is not caused by telomeres shortening, but is related to formation of gamma-H2AX, implicating DNA damage or uncapping of telomeres, which triggers genome instability. In conclusion, our results indicate that HIV-1 stimulates telomere elongation during latency, suggesting that HIV reservoir has greater capacity for clonal expansion and extended lifespan. Higher rates of apoptosis in response to BRACO19 treatment suggest that HIV reservoirs are more susceptible to targeting telomere maintenance and to inhibitors targeting DDR, which is also involved in stabilizing telomeres.