IMR Press / FBL / Volume 28 / Issue 12 / DOI: 10.31083/j.fbl2812324
Open Access Original Research
EGCG Restores Keratinocyte Autophagy to Promote Diabetic Wound Healing through the AMPK/ULK1 Pathway
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1 Department of Orthopaedics, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, 410004 Changsha, Hunan, China
2 Institute of Pediatrics, Laboratory of Pediatric Nephrology, Central South University, 410011 Changsha, Hunan, China
*Correspondence: 2018050831@usc.edu.cn (Liangdong Jiang); 15228449@qq.com (Mingjiang Liu)
These authors contributed equally.
Front. Biosci. (Landmark Ed) 2023, 28(12), 324; https://doi.org/10.31083/j.fbl2812324
Submitted: 18 April 2023 | Revised: 3 July 2023 | Accepted: 17 July 2023 | Published: 1 December 2023
(This article belongs to the Special Issue Plant Bioactive Molecules)
Copyright: © 2023 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.
Abstract

Background: Delayed wound healing, a common problem in patients with diabetes mellitus (DM), is associated with impaired keratinocyte autophagy. Epigallocatechin gallate (EGCG), a catechin, has been proven to promote diabetic wound healing. This study aims to explore the therapeutic mechanism of EGCG on diabetic wound healing. Methods: High glucose (HG)-induced keratinocytes and streptozotocin (STZ)-induced DM rats were prepared and intervened with EGCG to examine its therapeutic effects in in vivo and in vitro settings. The AMPK inhibitor, Compound C, was utilized to determine whether EGCG exerted its therapeutic effects through the AMPK/ULK1 pathway. Results: In vitro, EGCG improved HG-induced autophagy impairment in keratinocytes by increasing LC3II/LC3I, Becline1, and ATG5 levels and decreasing p62 level. Mechanically, EGCG activated the AMPK/ULK1 pathway, thereby promoting keratinocyte autophagy through the phosphorylation of AMPK and ULK1. Notably, EGCG promoted the proliferation, migration, synthesis and release of C-C motif chemokine ligand 2 (CCL2) in HG-treated keratinocytes. Furthermore, EGCG indirectly promoted the activation of fibroblasts, as evidenced by increased alpha-smooth muscle actin (α-SMA) and Collagen I levels. In vivo, EGCG promoted wound healing in DM rats, primarily by reducing inflammatory infiltration and increasing granulation tissue to promote wound epithelialization. Besides, EGCG promoted ATG5, KRT10, KRT14, TGF-β1, Collagen I, and α-SMA expressions in the neonatal epithelial tissues of DM rats. However, the use of Compound C reversed the effects of EGCG. Conclusions: These findings indicated that EGCG restored keratinocyte autophagy to promote diabetic wound healing through the AMPK/ULK1 pathway.

Keywords
diabetic cutaneous ulcers (DCU)
epigallocatechin gallate (EGCG)
AMPK/ULK1 pathway
keratinocytes
autophagy
Funding
kq2208441/Natural Science Foundation of Changsha
kq2208446/Natural Science Foundation of Changsha
YNKY202107/Key Project in Changsha Central Hospital
2020SK53304/Hunan Clinical Medical Technology Innovation Guidance Project
Figures
Fig. 1.
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