PTGS2 and cystitis: However, among previously infected mice (Sensitized and Resolved), TNFɑ signaling is sustained through 24 hpi only in Sensitized mice, who also experience high expression of bladder Ptgs2, which is known to mediate mucosal immune damage to the urothelium and precipitate severe chronic and recurrent cystitis (Hannan et al., 2010; O'Brien et al., 2016).