Mechanism of pain hypersensitivity of diabetic neuropathy involving functional interaction of TRP channels and AMP kinase

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K09048
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Pain science
• Research Institution: Hyogo University of Health Sciences
• Principal Investigator: Dai Yi 兵庫医療大学, 薬学部, 教授 (20330441)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 糖尿病性ニューロパチー

Outline of Final Research Achievements

In this study, we demonstrated a functional interaction between AMP activated protein kinase (AMPK) and transient receptor potential (TRP) channels in dorsal root ganglion (DRG) neurons, in which AMPK activation resulted in downregulation of membrane-associated TRPA1 and its channel activity in both short-term and long-term manner. Treatment with two AMPK activators, metformin or AICAR, inhibited TRPA1 activity in DRG neurons by decreasing the amount of membrane-associated TRPA1. Conversely, in diabetic db/db mice, AMPK activity was impaired in DRG neurons, and this was associated with a concomitant increase in membrane-associated TRPA1 and mechanical allodynia. Notably, these molecular and behavioral changes were normalized following treatment with AMPK activators. Our results identify AMPK as a previously unknown regulator of TRPA1 channels. AMPK modulation of TRPA1 could thus serve as an underlying mechanism and potential therapeutic molecular target in painful diabetic neuropathy.

Free Research Field

神経科学

Academic Significance and Societal Importance of the Research Achievements

本研究は、感覚神経に発現している疼痛センサー（TRPA1)は、エネルギー代謝センサー（AMPK)とそのシグナルによって負の制御を受ける新しい生理現象を解明した。本研究成果は、糖尿病や肥満症など体内エネルギー代謝異常による感覚神経機能の変調（疼痛過敏など）の発症機序を示唆した。また、メトホルミン（商品名メトグルコ）など細胞AMPKシグナルをコントロールする薬剤の疼痛緩和効果が証明された。
今後、これに基づく疼痛治療薬の開発や、既存AMPK薬剤の適応拡大に繋がる臨床試験が期待され、糖尿病性ニューロパチーの患者にとって希望をもたらすであろう。