NOD-like receptor protein 3 inflammasome drives postoperative mechanical pain in a sex-dependent manner

AM Cowie, AD Menzel, C O'Hara, MW Lawlor… - Pain, 2019 - journals.lww.com
AM Cowie, AD Menzel, C O'Hara, MW Lawlor, CL Stucky
Pain, 2019journals.lww.com
Postoperative pain management continues to be suboptimal because of the lack of effective
nonopioid therapies and absence of understanding of sex-driven differences. Here, we
asked how the NLRP3 inflammasome contributes to postoperative pain. Inflammasomes are
mediators of the innate immune system that are responsible for activation and secretion of IL-
1b upon stimulation by specific molecular signals. Peripheral IL-1b is known to contribute to
the mechanical sensitization induced by surgical incision. However, it is not known which …
Abstract
Postoperative pain management continues to be suboptimal because of the lack of effective nonopioid therapies and absence of understanding of sex-driven differences. Here, we asked how the NLRP3 inflammasome contributes to postoperative pain. Inflammasomes are mediators of the innate immune system that are responsible for activation and secretion of IL-1b upon stimulation by specific molecular signals. Peripheral IL-1b is known to contribute to the mechanical sensitization induced by surgical incision. However, it is not known which inflammasome mediates the IL-1b release after surgical incision. Among the 9 known inflammasomes, the NLRP3 inflammasome is ideally positioned to drive postoperative pain through IL-1b production because NLRP3 can be activated by factors that are released by incision. Here, we show that male mice that lack NLRP3 (NLRP3KO) recover from surgery-induced behavioral and neuronal mechanical sensitization faster and display less surgical site inflammation than mice expressing NLRP3 (wild-type). By contrast, female NLRP3KO mice exhibit minimal attenuation of the postoperative mechanical hypersensitivity and no change in postoperative inflammation compared with wild-type controls. Sensory neuron-specific deletion of NLRP3 revealed that in males, NLRP3 expressed in non-neuronal cells and potentially sensory neurons drives postoperative pain. However, in females, only the NLRP3 that may be expressed in sensory neurons contributes to postoperative pain where the nonneuronal cell contribution is NLRP3 independent. This is the first evidence of a key role for NLRP3 in postoperative pain and reveals immune-mediated sex differences in postoperative pain.
Lippincott Williams & Wilkins