Neuregulin1-ErbB4 Signaling in Spinal Cord Participates in Electroacupuncture Analgesia in Inflammatory Pain

Chaofan Wan; Yunlong Xu; Baoyan Cen; Yucen Xia; Lin Yao; Yuanjia Zheng; Jiaying Zhao; Su He; Yongjun Chen

doi:10.3389/fnins.2021.636348

Neuregulin1-ErbB4 Signaling in Spinal Cord Participates in Electroacupuncture Analgesia in Inflammatory Pain

Front Neurosci. 2021 Jan 28:15:636348. doi: 10.3389/fnins.2021.636348. eCollection 2021.

Authors

Chaofan Wan¹, Yunlong Xu^{1

2}, Baoyan Cen¹, Yucen Xia¹, Lin Yao¹, Yuanjia Zheng¹, Jiaying Zhao¹, Su He¹, Yongjun Chen^{1

3}

Affiliations

¹ South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China.
² Shenzhen Key Laboratory of Drug Addiction, CAS Key Laboratory of Brain Connectome and Manipulation, The Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China.
³ Guangdong-Hong Kong-Macao Greater Bay Area, Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, China.

Abstract

Chronic inflammatory pain is a severe clinical symptom that aggravates the life quality of patients and places a huge economic burden on individuals and society. As one complementary and alternative therapy, electroacupuncture (EA) is widely used in clinical practice to treat chronic inflammatory pain based on its safety and efficacy. Previous studies have revealed the potential role of adenosine, neuropeptides, and inflammatory factors in EA analgesia in various pain models, but the identity of some of the signaling pathways involved remain unknown. In the present study, we explored whether neuregulin1 (NRG1)-ErbB4 signaling is involved in EA analgesia in inflammatory pain. Repeated EA treatment at the acupoints Zusanli (ST36) and Sanyinjiao (SP6) for 3 consecutive days remarkably attenuated mechanical allodynia and thermal hyperalgesia in complete Freund's adjuvant (CFA)-treated mice, with an increased expression of NRG1 in spinal cord (SC). We found that ErbB4 kinase participated in both the EA and NRG1 mediated analgesic effects on inflammatory pain by pharmacological inhibition or genetic ablation ErbB4 in vivo. Intriguingly, the mice with conditional knockout of ErbB4 from PV⁺ interneurons in SC showed abnormal basal mechanical threshold. Meanwhile, NRG1 treatment could not relieve tactile allodynia in PV-Erbb4^-/- mice or AAV-PV-Erbb4^-/- mice after CFA injection. These experimental results suggest that regulating NRG1-ErbB4 signaling in SC could reduce pain hypersensitivity and contribute to EA analgesia in inflammatory pain.

Keywords: ErbB4; analgesia; electroacupuncture; inflammatory pain; neuregulin1; spinal cord.