Extracellular vesicles derived from fat-laden hepatocytes undergoing chemical hypoxia promote a pro-fibrotic phenotype in hepatic stellate cells.
Animals
Cell Communication
Cell Hypoxia
/ drug effects
Cobalt
/ pharmacology
Culture Media
/ metabolism
Disease Models, Animal
Disease Progression
Extracellular Vesicles
/ metabolism
Fatty Acids, Nonesterified
/ metabolism
Hep G2 Cells
Hepatic Stellate Cells
/ metabolism
Hepatocytes
/ metabolism
Humans
Hypoxia
/ blood
Hypoxia-Inducible Factor 1, alpha Subunit
/ agonists
Liver Cirrhosis
/ blood
Male
Mice
Non-alcoholic Fatty Liver Disease
/ blood
Oxidative Stress
Sleep Apnea, Obstructive
/ blood
Extracellular vesicles
Hypoxia
Liver fibrosis
Nonalcoholic fatty liver disease
Journal
Biochimica et biophysica acta. Molecular basis of disease
ISSN: 1879-260X
Titre abrégé: Biochim Biophys Acta Mol Basis Dis
Pays: Netherlands
ID NLM: 101731730
Informations de publication
Date de publication:
01 10 2020
01 10 2020
Historique:
received:
10
01
2020
revised:
30
05
2020
accepted:
01
06
2020
pubmed:
9
6
2020
medline:
15
12
2020
entrez:
9
6
2020
Statut:
ppublish
Résumé
The transition from steatosis to non-alcoholic steatohepatitis (NASH) is a key issue in non-alcoholic fatty liver disease (NAFLD). Observations in patients with obstructive sleep apnea syndrome (OSAS) suggest that hypoxia contributes to progression to NASH and liver fibrosis, and the release of extracellular vesicles (EVs) by injured hepatocytes has been implicated in NAFLD progression. To evaluate the effects of hypoxia on hepatic pro-fibrotic response and EV release in experimental NAFLD and to assess cellular crosstalk between hepatocytes and human hepatic stellate cells (LX-2). HepG2 cells were treated with fatty acids and subjected to chemically induced hypoxia using the hypoxia-inducible factor 1 alpha (HIF-1α) stabilizer cobalt chloride (CoCl2). Lipid droplets, oxidative stress, apoptosis and pro-inflammatory and pro-fibrotic-associated genes were assessed. EVs were isolated by ultracentrifugation. LX-2 cells were treated with EVs from hepatocytes. The CDAA-fed mouse model was used to assess the effects of intermittent hypoxia (IH) in experimental NASH. Chemical hypoxia increased steatosis, oxidative stress, apoptosis and pro-inflammatory and pro-fibrotic gene expressions in fat-laden HepG2 cells. Chemical hypoxia also increased the release of EVs from HepG2 cells. Treatment of LX2 cells with EVs from fat-laden HepG2 cells undergoing chemical hypoxia increased expression pro-fibrotic markers. CDAA-fed animals exposed to IH exhibited increased portal inflammation and fibrosis that correlated with an increase in circulating EVs. Chemical hypoxia promotes hepatocellular damage and pro-inflammatory and pro-fibrotic signaling in steatotic hepatocytes both in vitro and in vivo. EVs from fat-laden hepatocytes undergoing chemical hypoxia evoke pro-fibrotic responses in LX-2 cells.
Sections du résumé
BACKGROUND
The transition from steatosis to non-alcoholic steatohepatitis (NASH) is a key issue in non-alcoholic fatty liver disease (NAFLD). Observations in patients with obstructive sleep apnea syndrome (OSAS) suggest that hypoxia contributes to progression to NASH and liver fibrosis, and the release of extracellular vesicles (EVs) by injured hepatocytes has been implicated in NAFLD progression.
AIM
To evaluate the effects of hypoxia on hepatic pro-fibrotic response and EV release in experimental NAFLD and to assess cellular crosstalk between hepatocytes and human hepatic stellate cells (LX-2).
METHODS
HepG2 cells were treated with fatty acids and subjected to chemically induced hypoxia using the hypoxia-inducible factor 1 alpha (HIF-1α) stabilizer cobalt chloride (CoCl2). Lipid droplets, oxidative stress, apoptosis and pro-inflammatory and pro-fibrotic-associated genes were assessed. EVs were isolated by ultracentrifugation. LX-2 cells were treated with EVs from hepatocytes. The CDAA-fed mouse model was used to assess the effects of intermittent hypoxia (IH) in experimental NASH.
RESULTS
Chemical hypoxia increased steatosis, oxidative stress, apoptosis and pro-inflammatory and pro-fibrotic gene expressions in fat-laden HepG2 cells. Chemical hypoxia also increased the release of EVs from HepG2 cells. Treatment of LX2 cells with EVs from fat-laden HepG2 cells undergoing chemical hypoxia increased expression pro-fibrotic markers. CDAA-fed animals exposed to IH exhibited increased portal inflammation and fibrosis that correlated with an increase in circulating EVs.
CONCLUSION
Chemical hypoxia promotes hepatocellular damage and pro-inflammatory and pro-fibrotic signaling in steatotic hepatocytes both in vitro and in vivo. EVs from fat-laden hepatocytes undergoing chemical hypoxia evoke pro-fibrotic responses in LX-2 cells.
Identifiants
pubmed: 32512191
pii: S0925-4439(20)30204-0
doi: 10.1016/j.bbadis.2020.165857
pii:
doi:
Substances chimiques
Culture Media
0
Fatty Acids, Nonesterified
0
HIF1A protein, human
0
Hypoxia-Inducible Factor 1, alpha Subunit
0
Cobalt
3G0H8C9362
cobaltous chloride
EVS87XF13W
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
165857Informations de copyright
Copyright © 2020 The Author(s). Published by Elsevier B.V. All rights reserved.
Déclaration de conflit d'intérêts
Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.