Basic Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 14, 2021; 27(14): 1419-1434
Published online Apr 14, 2021. doi: 10.3748/wjg.v27.i14.1419
Lipotoxic hepatocyte-derived exosomal miR-1297 promotes hepatic stellate cell activation through the PTEN signaling pathway in metabolic-associated fatty liver disease
Xin Luo, Sheng-Zheng Luo, Zi-Xin Xu, Cui Zhou, Zheng-Hong Li, Xiao-Yan Zhou, Ming-Yi Xu
Xin Luo, Sheng-Zheng Luo, Zi-Xin Xu, Cui Zhou, Zheng-Hong Li, Xiao-Yan Zhou, Ming-Yi Xu, Department of Gastroenterology, Shanghai General Hospital, Shanghai 200080, China
Author contributions: Xu MY designed the research; Luo X and Luo SZ performed the research; Xu ZX and Li ZH analyzed the data; Luo X wrote the paper; Zhou C and Zhou XY developed software necessary for performing the study.
Supported by The National Natural Science Foundation of China (General Program), No. 81770597; and the Development Program of China during the 13th Five-year Plan Period, No. 2017ZX10203202003005.
Institutional review board statement: The study was reviewed and approved by the Institutional Review Board at Shanghai General Hospital.
Institutional animal care and use committee statement: All animal experiments conformed to the internationally accepted principles for the care and use of laboratory animals and approved by the Ethical Committee of the Shanghai General Hospital.
Conflict-of-interest statement: The authors hereby declare that no conflict of interest exists.
Data sharing statement: No additional data are available.
ARRIVE guidelines statement: 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: Ming-Yi Xu, MD, Chief Doctor, Professor, Department of Gastroenterology, Shanghai General Hospital, No. 100 Haining Road, Shanghai 200080, China. xumingyi2014@163.com
Received: October 10, 2020
Peer-review started: October 10, 2020
First decision: January 23, 2021
Revised: February 5, 2021
Accepted: March 7, 2021
Article in press: March 7, 2021
Published online: April 14, 2021
Abstract
BACKGROUND

Exosomes play an important role in metabolic-associated fatty liver disease (MAFLD), but the mechanism by which exosomes participate in MAFLD still remain unclear.

AIM

To figure out the function of lipotoxic exosomal miR-1297 in MAFLD.

METHODS

MicroRNA sequencing was used to detect differentially expressed miRNAs (DE-miR) in lipotoxic exosomes derived from primary hepatocytes. Bioinformatic tools were applied to analyze the target genes and pathways regulated by the DE-miRs. Quantitative real-time PCR (qPCR) was conducted for the verification of DE-miRs. qPCR, western blot, immunofluorescence staining and ethynyl-20-deoxyuridine assay were used to evaluate the function of lipotoxic exosomal miR-1297 on hepatic stellate cells (LX2 cells). A luciferase reporter experiment was performed to confirm the relationship of miR-1297 and its target gene PTEN.

RESULTS

MicroRNA sequencing revealed that there were 61 exosomal DE-miRs (P < 0.05) with a fold-change > 2 from palmitic acid treated primary hepatocytes compared with the vehicle control group. miR-1297 was the most highly upregulated according to the microRNA sequencing. Bioinformatic tools showed a variety of target genes and pathways regulated by these DE-miRs were related to liver fibrosis. miR-1297 was overexpressed in exosomes derived from lipotoxic hepatocytes by qPCR. Fibrosis promoting genes (α-SMA, PCNA) were altered in LX2 cells after miR-1297 overexpression or miR-1297-rich lipotoxic exosome incubation via qPCR and western blot analysis. Immunofluorescence staining and ethynyl-20-deoxyuridine staining demonstrated that the activation and proliferation of LX2 cells were also promoted after the above treatment. PTEN was found to be the target gene of miR-1297 and knocking down PTEN contributed to the activation and proliferation of LX2 cells via modulating the PI3K/AKT signaling pathway.

CONCLUSION

miR-1297 was overexpressed in exosomes derived from lipotoxic hepatocytes. The lipotoxic hepatocyte-derived exosomal miR-1297 could promote the activation and proliferation of hepatic stellate cells through the PTEN/PI3K/AKT signaling pathway, accelerating the progression of MAFLD.

Keywords: Metabolic-associated fatty liver disease, miRNA-1297, Exosome, Hepatic stellate cell, PTEN, Liver fibrosis

Core Tip: In this study, the expression of miR-1297 was increased in exosomes derived from primary hepatocytes. Exosomal miR-1297 from lipotoxic LO2 (a hepatocyte cell line) could promote LX2 (a hepatic stellate cell line) activation and proliferation by regulating the PTEN/PI3K/ATK pathway. Currently, the study between exosomes and metabolic-associated fatty liver disease is very limited. This is the first time that exosomal miR-1297 from lipotoxic hepatocytes was confirmed to accelerate liver fibrosis, and the new mechanism may become a promising treatment target for metabolic-associated fatty liver disease.