Poly(ADP)ribose polymerase 9 contributes to early protection against Mycobacterium tuberculosis infection in mice

PARP family members have essential roles in the cell and the role of PARP1 in DNA damage repair has been well characterized, however there is a paucity of studies assessing the role PARP9 plays in biological processes. PARP1 is a known substrate for the pro-apoptotic caspase 3 which cleaved PARP1 and drives apoptosis. We postulated that similar to PARP1, PARP9 might also play essential roles in cell death pathways and the absence of PARP9 might influence mycobacterial infection. Utilizing C57Bl6 and Parp9-/- mice infected with the clinical virulent strain HN878 infection we show that absence of PARP9 enhances mycobacterial disease burden in mice and enhances inflammatory changes especially at early time-points post-infection. Our findings provide novel information on less characterized isoform of PARP, Parp9 in mycobacterial infections and suggesting its potential as an early biomarker for tuberculosis disease severity and outcome.