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Role of Src kinase in regulating protein kinase C mediated phosphorylation of TRPV1. Eur J Pain 2022 Oct;26(9):1967-1978

Date

07/29/2022

Pubmed ID

35900227

Pubmed Central ID

PMC9483845

DOI

10.1002/ejp.2017

Scopus ID

2-s2.0-85135524078 (requires institutional sign-in at Scopus site)   7 Citations

Abstract

BACKGROUND: Transient receptor potential vanilloid-1 (TRPV1), activated by heat, acidic pH, endogenous vanilloids and capsaicin, is essential for thermal hyperalgesia. Under inflammatory conditions, phosphorylation of TRPV1 by protein kinase C (PKC) can sensitize the channel and decrease the activation threshold. Src kinase also phosphorylates TRPV1, promoting channel trafficking to the plasma membrane. These post-translational modifications are important for several chronic pain conditions. This study presents a previously undescribed relationship between Src and PKC phosphorylation of TRPV1, influencing the thermal hypersensitivity associated with TRPV1 activation.

METHODS: We assessed TRPV1 channel activity using intracellular calcium imaging and patch-clamp electrophysiology in mouse dorsal root ganglion cultures. Additionally, we used behavioural experiments to evaluate plantar thermal sensitivity following intraplantar injections of activators of known modulators of TRPV1 with and without an Src antagonist.

RESULTS: Using calcium imaging and patch-clamp techniques, we demonstrated that pharmacological inhibition of Src kinase or mutation of the Src phosphorylation site on TRPV1 prevented PKC but not PKA-mediated sensitization of TRPV1 in vitro. We found that intraplantar injection of the PKC activator phorbol 12-myristate 13-acetate (PMA) or bradykinin produces thermal hypersensitivity that can be attenuated by pharmacological inhibition of Src. Additionally, complete Freund's Adjuvant (CFA)-induced inflammatory hypersensitivity could also be attenuated by local Src kinase inhibition.

CONCLUSIONS: Our data demonstrate that Src phosphorylation is critical for PKC-mediated sensitization of TRPV1. Further, in a model of inflammatory pain, CFA, Src kinase inhibition could reduce thermal hypersensitivity. Targeting of Src kinase may have analgesic benefits in inflammatory pain conditions.

SIGNIFICANCE: Src kinase-mediated phosphorylation of TRPV1 is a critical regulator of the PKC-induced sensitization induced by multiple inflammatory mediators. This suggest a new regulatory mechanism governing TRPV1 function and a potential therapeutic target for inflammatory type pain, including cancer pain where Src antagonists are currently utilized.

Author List

Robilotto GL, Mohapatra DP, Shepherd AJ, Mickle AD

Author

Aaron D. Mickle PhD Associate Professor in the Physiology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Calcium
Capsaicin
Chronic Pain
Freund's Adjuvant
Ganglia, Spinal
Hyperalgesia
Mice
Phosphorylation
Protein Kinase C
TRPV Cation Channels
src-Family Kinases