Protease-Activated Receptor 2 (PAR2) expressed in sensory neurons contributes to signs of pain and neuropathy in paclitaxel treated mice

Abstract

Background and Purpose: Chemotherapy-Induced Peripheral Neuropathy (CIPN) is a common, dose-limiting side effect of cancer therapy. Protease-activated receptor 2 (PAR2) is implicated in a variety of pathologies, including CIPN. In this study, we demonstrate the role of PAR2 expressed in sensory neurons in a paclitaxel (PTX)-induced model of CIPN in mice. Experimental Approach: CIPN was induced in both PAR2 knockout/WT mice and mice with PAR2 ablated in sensory neurons via the intraperitoneal injection of paclitaxel. In vivo behavioral studies were done in mice using von Frey filaments and the Mouse Grimace Scale. We then examined immunohistochemical staining of dorsal root ganglion (DRG) and hind paw skin samples from CIPN mice to measure satellite cell gliosis and intra-epidermal nerve fiber (IENF) density. Pharmacological reversal of CIPN pain was tested with the PAR2 antagonist C781 Key Results: Mechanical allodynia caused by paclitaxel treatment was alleviated in PAR2 knockout mice of both sexes. In the PAR2 sensory neuronal conditional knockout (cKO) mice, both mechanical allodynia and facial grimacing were attenuated in mice of both sexes. In the dorsal root ganglion of the paclitaxel-treated PAR2 cKO mice, satellite glial cell activation was reduced compared to control mice. IENF density analysis of the skin showed that the paclitaxel-treated control mice have a reduction in nerve fiber density while the PAR2 cKO mice had a comparable skin innervation as the vehicle-treated animals. Similar results were seen with satellite cell gliosis in the DRG where gliosis induced by PTX was absent in PAR cKO mice. Finally, C781 was able to transiently reverse established PTX-evoked mechanical allodynia. Conclusions and Implications: Our work demonstrates that PAR2 expressed in sensory neurons plays a key role in paclitaxel-induced mechanical allodynia, spontaneous pain and signs of neuropathy, suggesting PAR2 as a possible therapeutic target in multiple aspects of paclitaxel CIPN.

Naringenin relieves paclitaxel‐induced pain by suppressing calcitonin gene‐related peptide signalling and enhances the anti‐tumour action of paclitaxel

“…There is accumulating evidence for the intricate cross‐talk between macrophages, glial cells and nociceptors in the development and maintenance of chemotherapy‐induced neuropathic pain, within both the peripheral and central nervous systems (Chen et al, 2020; Gao et al, 2022; Kume et al, 2023; Liu et al, 2019; Mei et al, 2023; Warwick & Hanani, 2013; Yan et al, 2019; Yu et al, 2020; Zhang et al, 2013, 2016). Studies have revealed that paclitaxel treatment activates immune and glial cells, resulting in the release of various pro‐inflammatory mediators, including TNF‐α, IL‐1β, IL‐6, IL‐23, IL‐36, stromal‐derived cell factor 1, CCL2 and CXCL1.…”