1. Academic Validation
  2. Catalpolaglycone disrupts mitochondrial thermogenesis by specifically binding to a conserved lysine residue of UCP2 on the proton leak tunnel

Catalpolaglycone disrupts mitochondrial thermogenesis by specifically binding to a conserved lysine residue of UCP2 on the proton leak tunnel

  • Phytomedicine. 2024 Jan 14:125:155356. doi: 10.1016/j.phymed.2024.155356.
Fukui Shen 1 Wen Yang 1 Guoqing Luan 1 Jiamin Peng 1 Zhenqiang Li 1 Jie Gao 2 Yuanyuan Hou 3 Gang Bai 1
Affiliations

Affiliations

  • 1 State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Tianjin 300353, China.
  • 2 State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Tianjin 300353, China. Electronic address: gaojie@nankai.edu.cn.
  • 3 State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Tianjin 300353, China. Electronic address: houyy@nankai.edu.cn.
Abstract

Background: Catalpol (CAT), a naturally occurring iridoid glycoside sourced from the root of Rehmannia glutinosa, affects mitochondrial metabolic functions. However, the mechanism of action of CAT against pyrexia and its plausible targets remain to be fully elucidated.

Purpose: This study aimed to identify the specific targets of CAT for blocking mitochondrial thermogenesis and to unveil the unique biological mechanism of action of the orthogonal binding mode between the hemiacetal group and lysine residue on the target protein in vivo.

Methods: Lipopolysaccharide (LPS)/ carbonyl cyanide 3-chlorophenylhydrazone (CCCP)-induced fever models were established to evaluate the potential antipyretic effects of CAT. An alkenyl-modified CAT probe was designed to identify and capture potential targets. Binding capacity was tested using in-gel imaging and a cellular thermal shift assay. The underlying antipyretic mechanisms were explored using biochemical and molecular biological methods. Catalpolaglycone (CA) was coupled with protein profile identification and molecular docking analysis to evaluate and identify its binding mode to UCP2.

Results: After deglycation of CAT in vivo, the hemiacetal group in CA covalently binds to Lys239 of UCP2 in the mitochondria of the liver via an ɛ-amine nucleophilic addition. This irreversible binding affects proton leakage and improves mitochondrial membrane potential and ADP/ATP transformation efficiency, leading to an antipyretic effect.

Conclusion: Our findings highlight the potential role of CA in modulating UCP2 activity or function within the mitochondria and open new avenues for investigating the therapeutic effects of CA on mitochondrial homeostasis.

Keywords

Antipyretic; Catalpol; Covalent inhibition; Mitochondrial respiration; UCP2.

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