Repurposing cancer drugs identifies kenpaullone which ameliorates pathologic pain in preclinical models via normalization of inhibitory neurotransmission

Michele Yeo,Peng Wang,Kaiyuan Wang,Sharat Chandra,Qian Zeng,Andrey Bortsov,Maria Lioudyno,Ru-Rong Ji,Gang Chen,Yong Chen,Changyu Jiang,Jorge Busciglio,Wolfgang Liedtke,Zilong Wang

doi:10.1038/s41467-021-26270-3

Abstract

Inhibitory GABA-ergic neurotransmission is fundamental for the adult vertebrate central nervous system and requires low chloride concentration in neurons, maintained by KCC2, a neuroprotective ion transporter that extrudes intracellular neuronal chloride. To identify Kcc2 gene expression‑enhancing compounds, we screened 1057 cell growth-regulating compounds in cultured primary cortical neurons. We identified kenpaullone (KP), which enhanced Kcc2/KCC2 expression and function in cultured rodent and human neurons by inhibiting GSK3ß. KP effectively reduced pathologic pain-like behavior in mouse models of nerve injury and bone cancer. In a nerve-injury pain model, KP restored Kcc2 expression and GABA-evoked chloride reversal potential in the spinal cord dorsal horn. Delta-catenin, a phosphorylation-target of GSK3ß in neurons, activated the Kcc2 promoter via KAISO transcription factor. Transient spinal over-expression of delta-catenin mimicked KP analgesia. Our findings of a newly repurposed compound and a novel, genetically-encoded mechanism that each enhance Kcc2 gene expression enable us to re-normalize disrupted inhibitory neurotransmission through genetic re-programming.

Highlights

Inhibitory GABA-ergic neurotransmission is fundamental for the adult vertebrate central nervous system and requires low chloride concentration in neurons, maintained by KCC2, a neuroprotective ion transporter that extrudes intracellular neuronal chloride
With the above findings and in view of the spinal cord dorsal horn (SCDH) as the likely site of analgesic action of KP3,6, we investigated the effect of nerve injury on Kcc[2] expression and functioning in the superficial SCDH as well as its response to KP
Running compound-2 and GSK3ß through our molecular dynamics simulation replicated their binding as experimentally verified by X-ray crystallography. These findings extend our result with kinase inhibitors that selectively target glycogen synthase kinase-3 (GSK3) or CKDs, so that the likelihood increases that the GSK3ß-inhibitory function of KP is responsible for its Kcc2/ KCC2 gene expression-enhancing effect in neurons

Summary

Introduction

Inhibitory GABA-ergic neurotransmission is fundamental for the adult vertebrate central nervous system and requires low chloride concentration in neurons, maintained by KCC2, a neuroprotective ion transporter that extrudes intracellular neuronal chloride. KCC2 expression is attenuated in the primary sensory gate in spinal cord dorsal horn (SCDH) neurons This key pathophysiological mechanism contributes to an imbalance of excitation/inhibition because it corrupts inhibitory neurotransmission, leading to inhibitory circuit malfunction[5,7,11,20,21,22,23,24]. After KP treatment, patch-clamp recordings revealed more negative, electrically more stable GABA-evoked chloride reversal potentials in SCDH pain relay neurons of mice subjected to nerve constriction injury In vivo, these mice showed robust analgesia in response to KP, and defective expression of KCC2 in the SCDH was repaired by KP

Methods

Results

Conclusion