Gegen Qinlian decoction maintains colonic mucosal homeostasis in acute/chronic ulcerative colitis via bidirectionally modulating dysregulated Notch signaling

Yaxing Zhao; Haofan Luan; Hui Gao; Xiaojun Wu; Yubin Zhang; Ruiyan Li

doi:10.1016/j.phymed.2020.153182

Gegen Qinlian decoction maintains colonic mucosal homeostasis in acute/chronic ulcerative colitis via bidirectionally modulating dysregulated Notch signaling

Phytomedicine. 2020 Mar:68:153182. doi: 10.1016/j.phymed.2020.153182. Epub 2020 Feb 7.

Authors

Yaxing Zhao¹, Haofan Luan¹, Hui Gao¹, Xiaojun Wu², Yubin Zhang³, Ruiyan Li⁴

Affiliations

¹ State Key Laboratory of Natural Medicines, Department of Biochemistry, China Pharmaceutical University, 24 Tongjia Xiang, Nanjing 210009, China.
² Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
³ State Key Laboratory of Natural Medicines, Department of Biochemistry, China Pharmaceutical University, 24 Tongjia Xiang, Nanjing 210009, China. Electronic address: ybzhang@cpu.edu.cn.
⁴ State Key Laboratory of Natural Medicines, Department of Biochemistry, China Pharmaceutical University, 24 Tongjia Xiang, Nanjing 210009, China. Electronic address: 1020061778@cpu.edu.cn.

PMID: 32065953
DOI: 10.1016/j.phymed.2020.153182

Abstract

Background: Gegen Qinlian decoction (GQ) is a well-known traditional Chinese medicine that has been clinically proven to be effective in treating ulcerative colitis (UC). However, its therapeutic mechanism has not been fully elucidated. Notch signaling plays an essential role in the regeneration of the intestinal epithelium.

Purpose: This study was designed to ascertain the mechanism by which GQ participates in the recovery of the colonic mucosa by regulating Notch signaling in acute and chronic UC models.

Methods: Acute and chronic UC mice (C57BL/6) were established with 3 and 2% dextran sulfate sodium (DSS), respectively, and treated with oral administration of GQ. The expression of the Notch target gene Hes1 and the Notch-related proteins RBP-J, MAML and Math1 was analyzed by western blotting. PTEN mRNA levels were detected by qRT-PCR. Mucin production that is characteristic of goblet cells was determined by Alcian blue/periodic acid-Schiff staining and verified by examining MUC2 mRNA levels by qRT-PCR. Cell proliferation was assayed by immunohistochemistry analysis of Ki67. HT-29 and FHC cells and Toll-like receptor 4 knockout (TLR4^-/-) acute UC mice were also used in this study.

Results: GQ restored the injured colonic mucosa in both acute and chronic UC models. We found that Notch signaling was hyperactive in acute UC mice and hypoactive in chronic UC mice. GQ downregulated Hes1, RBP-J and MAML proteins and augmented goblet cells in the acute UC models, whereas GQ upregulated Hes1, RBP-J and MAML proteins in chronic UC mice, reducing goblet cell differentiation and promoting crypt base columnar (CBC) stem cell proliferation. Hes1 mRNA was suppressed in TLR4^-/- UC mice, and GQ treatment reversed this effect. In vitro, GQ reduced Hes1 protein in Notch-activated HT29 and FHC cells but increased Hes1 protein in Notch-inhibited cells.

Conclusions: GQ restored the colonic epithelium by maintaining mucosal homeostasis via bidirectional regulation of Notch signaling in acute/chronic UC models.

Keywords: Bidirectional regulation; Colonic mucosa; Gegen Qinlian decoction; Notch signaling; Regeneration; Ulcerative colitis.

MeSH terms

Acute Disease
Animals
Cell Differentiation / physiology
Cell Proliferation
Chronic Disease
Colitis, Ulcerative / chemically induced
Colitis, Ulcerative / drug therapy*
Colitis, Ulcerative / metabolism
Dextran Sulfate / toxicity
Drugs, Chinese Herbal / pharmacology*
Female
Gastric Mucosa / drug effects*
Gastric Mucosa / pathology
Goblet Cells / drug effects
HT29 Cells
Homeostasis / drug effects
Humans
Intestinal Mucosa / drug effects
Intestinal Mucosa / metabolism
Intestinal Mucosa / pathology
Mice, Inbred C57BL
Receptors, Notch / metabolism*
Signal Transduction / drug effects
Transcription Factor HES-1 / genetics
Transcription Factor HES-1 / metabolism

Substances

Drugs, Chinese Herbal
Hes1 protein, mouse
Receptors, Notch
Transcription Factor HES-1
gegenqinlian
Dextran Sulfate