Basic Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 28, 2021; 27(40): 6908-6926
Published online Oct 28, 2021. doi: 10.3748/wjg.v27.i40.6908
Transforming growth factor beta-1 upregulates glucose transporter 1 and glycolysis through canonical and noncanonical pathways in hepatic stellate cells
Ming-Yu Zhou, Ming-Liang Cheng, Tao Huang, Rui-Han Hu, Gao-Liang Zou, Hong Li, Bao-Fang Zhang, Juan-Juan Zhu, Yong-Mei Liu, Yang Liu, Xue-Ke Zhao
Ming-Yu Zhou, Ming-Liang Cheng, Tao Huang, Rui-Han Hu, Xue-Ke Zhao, Department of Internal Medicine, Guizhou Medical University, Guiyang 550001, Guizhou Province, China
Ming-Yu Zhou, Ming-Liang Cheng, Gao-Liang Zou, Hong Li, Bao-Fang Zhang, Juan-Juan Zhu, Yang Liu, Xue-Ke Zhao, Department of Infectious Diseases, Affiliated Hospital of Guizhou Medical University, Guiyang 550004, Guizhou Province, China
Yong-Mei Liu, Clinical Laboratory Center, Affiliated Hospital of Guizhou Medical University, Guiyang 550004, Guizhou Province, China
Author contributions: Zhao XK and Cheng ML designed the study; Zhou MY, Huang T and Hu RH performed most of the experiments and wrote the article; all authors contributed to the design and interpretation of the study; Zhou MY, Huang T and Hu RH contributed equally to this work; all authors approved the final version of the article.
Supported by National Natural Science Foundation of China, No. 82060116, No. 81860115 and No. 81960118; and Guizhou Science and Technology Support Project Fund, No. [2021] 058.
Institutional review board statement: This study was approved by the Institutional Review Board of the Affiliated Hospital of Guizhou Medical University.
Institutional animal care and use committee statement: All animal experiments conformed to the internationally accepted principles for the care and use of laboratory animals (license No. 2000719). All animal interventions were approved by the Institutional Animal Care and Use Committee (IACUC) of Guizhou Medical University.
Conflict-of-interest statement: The authors declare no conflicts of interest related to this study.
Data sharing statement: No additional data are available.
ARRIVE guidelines statement: The authors have read the ARRIVE Guidelines, and the manuscript was prepared and revised according to the ARRIVE Guidelines.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Xue-Ke Zhao, MD, PhD, Chief Physician, Professor, Department of Infectious Diseases, Affiliated Hospital of Guizhou Medical University, No. 28 Guiyi Road, Guiyang 550004, Guizhou Province, China. zhaoxueke1@163.com
Received: April 30, 2021
Peer-review started: April 30, 2021
First decision: July 2, 2021
Revised: July 19, 2021
Accepted: September 8, 2021
Article in press: September 8, 2021
Published online: October 28, 2021
Processing time: 180 Days and 3.8 Hours
Abstract
BACKGROUND

Hepatic stellate cells (HSCs) are the key effector cells mediating the occurrence and development of liver fibrosis, while aerobic glycolysis is an important metabolic characteristic of HSC activation. Transforming growth factor-β1 (TGF-β1) induces aerobic glycolysis and is a driving factor for metabolic reprogramming. The occurrence of glycolysis depends on a high glucose uptake level. Glucose transporter 1 (GLUT1) is the most widely distributed glucose transporter in the body and mainly participates in the regulation of carbohydrate metabolism, thus affecting cell proliferation and growth. However, little is known about the relationship between TGF-β1 and GLUT1 in the process of liver fibrosis and the molecular mechanism underlying the promotion of aerobic glycolysis in HSCs.

AIM

To investigate the mechanisms of action of GLUT1, TGF-β1 and aerobic glycolysis in the process of HSC activation during liver fibrosis.

METHODS

Immunohistochemical staining and immunofluorescence assays were used to examine GLUT1 expression in fibrotic liver tissue. A Seahorse extracellular flux (XF) analyzer was used to examine changes in aerobic glycolytic flux, lactate production levels and glucose consumption levels in HSCs upon TGF-β1 stimulation. The mechanism by which TGF-β1 induces GLUT1 protein expression in HSCs was further explored by inhibiting/promoting the TGF-β1/mothers-against-decapentaplegic-homolog 2/3 (Smad2/3) signaling pathway and inhibiting the p38 and phosphoinositide 3-kinase (PI3K)/AKT signaling pathways. In addition, GLUT1 expression was silenced to observe changes in the growth and proliferation of HSCs. Finally, a GLUT1 inhibitor was used to verify the in vivo effects of GLUT1 on a mouse model of liver fibrosis.

RESULTS

GLUT1 protein expression was increased in both mouse and human fibrotic liver tissues. In addition, immunofluorescence staining revealed colocalization of GLUT1 and alpha-smooth muscle actin proteins, indicating that GLUT1 expression was related to the development of liver fibrosis. TGF-β1 caused an increase in aerobic glycolysis in HSCs and induced GLUT1 expression in HSCs by activating the Smad, p38 MAPK and P13K/AKT signaling pathways. The p38 MAPK and Smad pathways synergistically affected the induction of GLUT1 expression. GLUT1 inhibition eliminated the effect of TGF-β1 on HSC proliferation and migration. A GLUT1 inhibitor was administered in a mouse model of liver fibrosis, and GLUT1 inhibition reduced the degree of liver inflammation and liver fibrosis.

CONCLUSION

TGF-β1 induces GLUT1 expression in HSCs, a process related to liver fibrosis progression. In vitro experiments revealed that TGF-β1-induced GLUT1 expression might be one of the mechanisms mediating the metabolic reprogramming of HSCs. In addition, in vivo experiments also indicated that the GLUT1 protein promotes the occurrence and development of liver fibrosis.

Keywords: Gene regulation; Glycolysis; Liver fibrosis; Glucose transporter 1; Transforming growth factor-β1

Core Tip: Liver fibrosis is a repair response of the liver to various chronic injuries. However, fibrosis may eventually evolve into liver cirrhosis or even liver cancer if it progresses. Hepatic stellate cell activation is the initiating factor for liver fibrosis. Transforming growth factor-β1 (TGF-β1) is a pleiotropic cytokine that induces aerobic glycolysis. Glucose transporter 1 (GLUT1) regulates glucose metabolism. This study examined the effects of TGF-β1-mediated pathways on GLUT1 expression in vivo and in vitro, explored the relationship between GLUT1 and TGF-β1 and further investigated the potential underlying mechanisms.