Lipid-Induced Signaling Causes Release of Inflammatory Extracellular Vesicles from Hepatocytes

Petra Hirsova, Samar C Ibrahim, Anuradha Krishnan, Vikas K. Verma, Steven F. Bronk, Nathan W. Werneburg, Michael R. Charlton, Vijay Shah, Harmeet M Malhi, Gregory James Gores

Research output: Contribution to journalArticle

106 Citations (Scopus)

Abstract

Background & Aims Hepatocyte cellular dysfunction and death induced by lipids and macrophage-associated inflammation are characteristics of nonalcoholic steatohepatitis (NASH). The fatty acid palmitate can activate death receptor 5 (DR5) on hepatocytes, leading to their death, but little is known about how this process contributes to macrophage-associated inflammation. We investigated whether lipid-induced DR5 signaling results in the release of extracellular vesicles (EVs) from hepatocytes, and whether these can induce an inflammatory macrophage phenotype. Methods Primary mouse and human hepatocytes and Huh7 cells were incubated with palmitate, its metabolite lysophosphatidylcholine, or diluent (control). The released EV were isolated, characterized, quantified, and applied to macrophages. C57BL/6 mice were placed on chow or a diet high in fat, fructose, and cholesterol to induce NASH. Some mice also were given the ROCK1 inhibitor fasudil; 2 weeks later, serum EVs were isolated and characterized by immunoblot and nanoparticle-tracking analyses. Livers were collected and analyzed by histology, immunohistochemistry, and quantitative polymerase chain reaction. Results Incubation of primary hepatocytes and Huh7 cells with palmitate or lysophosphatidylcholine increased their release of EVs, compared with control cells. This release was reduced by inactivating mediators of the DR5 signaling pathway or rho-associated, coiled-coil-containing protein kinase 1 (ROCK1) inhibition. Hepatocyte-derived EVs contained tumor necrosis factor-related apoptosis-inducing ligand and induced expression of interleukin 1β and interleukin 6 messenger RNAs in mouse bone marrow-derived macrophages. Activation of macrophages required DR5 and receptor-interacting protein kinase 1. Administration of the ROCK1 inhibitor fasudil to mice with NASH reduced serum levels of EVs; this reduction was associated with decreased liver injury, inflammation, and fibrosis. Conclusions Lipids, which stimulate DR5, induce release of hepatocyte EVs, which activate an inflammatory phenotype in macrophages. Strategies to inhibit ROCK1-dependent release of EVs by hepatocytes might be developed for the treatment of patients with NASH.

Original languageEnglish (US)
Pages (from-to)956-967
Number of pages12
JournalGastroenterology
Volume150
Issue number4
DOIs
StatePublished - Apr 1 2016

Fingerprint

TNF-Related Apoptosis-Inducing Ligand Receptors
Hepatocytes
Lipids
rho-Associated Kinases
Macrophages
Palmitates
Lysophosphatidylcholines
Protein Kinase Inhibitors
Inflammation
Receptor-Interacting Protein Serine-Threonine Kinases
Phenotype
Macrophage Activation
Extracellular Vesicles
Liver
High Fat Diet
Fructose
Serum
Interleukin-1
Inbred C57BL Mouse
Nanoparticles

Keywords

  • Cell Death
  • Exosomes
  • Lipotoxic
  • Microvesicles

ASJC Scopus subject areas

  • Gastroenterology

Cite this

Lipid-Induced Signaling Causes Release of Inflammatory Extracellular Vesicles from Hepatocytes. / Hirsova, Petra; Ibrahim, Samar C; Krishnan, Anuradha; Verma, Vikas K.; Bronk, Steven F.; Werneburg, Nathan W.; Charlton, Michael R.; Shah, Vijay; Malhi, Harmeet M; Gores, Gregory James.

In: Gastroenterology, Vol. 150, No. 4, 01.04.2016, p. 956-967.

Research output: Contribution to journalArticle

Hirsova, Petra ; Ibrahim, Samar C ; Krishnan, Anuradha ; Verma, Vikas K. ; Bronk, Steven F. ; Werneburg, Nathan W. ; Charlton, Michael R. ; Shah, Vijay ; Malhi, Harmeet M ; Gores, Gregory James. / Lipid-Induced Signaling Causes Release of Inflammatory Extracellular Vesicles from Hepatocytes. In: Gastroenterology. 2016 ; Vol. 150, No. 4. pp. 956-967.
@article{cc9dcf837b854d0db2553ebedbed0428,
title = "Lipid-Induced Signaling Causes Release of Inflammatory Extracellular Vesicles from Hepatocytes",
abstract = "Background & Aims Hepatocyte cellular dysfunction and death induced by lipids and macrophage-associated inflammation are characteristics of nonalcoholic steatohepatitis (NASH). The fatty acid palmitate can activate death receptor 5 (DR5) on hepatocytes, leading to their death, but little is known about how this process contributes to macrophage-associated inflammation. We investigated whether lipid-induced DR5 signaling results in the release of extracellular vesicles (EVs) from hepatocytes, and whether these can induce an inflammatory macrophage phenotype. Methods Primary mouse and human hepatocytes and Huh7 cells were incubated with palmitate, its metabolite lysophosphatidylcholine, or diluent (control). The released EV were isolated, characterized, quantified, and applied to macrophages. C57BL/6 mice were placed on chow or a diet high in fat, fructose, and cholesterol to induce NASH. Some mice also were given the ROCK1 inhibitor fasudil; 2 weeks later, serum EVs were isolated and characterized by immunoblot and nanoparticle-tracking analyses. Livers were collected and analyzed by histology, immunohistochemistry, and quantitative polymerase chain reaction. Results Incubation of primary hepatocytes and Huh7 cells with palmitate or lysophosphatidylcholine increased their release of EVs, compared with control cells. This release was reduced by inactivating mediators of the DR5 signaling pathway or rho-associated, coiled-coil-containing protein kinase 1 (ROCK1) inhibition. Hepatocyte-derived EVs contained tumor necrosis factor-related apoptosis-inducing ligand and induced expression of interleukin 1β and interleukin 6 messenger RNAs in mouse bone marrow-derived macrophages. Activation of macrophages required DR5 and receptor-interacting protein kinase 1. Administration of the ROCK1 inhibitor fasudil to mice with NASH reduced serum levels of EVs; this reduction was associated with decreased liver injury, inflammation, and fibrosis. Conclusions Lipids, which stimulate DR5, induce release of hepatocyte EVs, which activate an inflammatory phenotype in macrophages. Strategies to inhibit ROCK1-dependent release of EVs by hepatocytes might be developed for the treatment of patients with NASH.",
keywords = "Cell Death, Exosomes, Lipotoxic, Microvesicles",
author = "Petra Hirsova and Ibrahim, {Samar C} and Anuradha Krishnan and Verma, {Vikas K.} and Bronk, {Steven F.} and Werneburg, {Nathan W.} and Charlton, {Michael R.} and Vijay Shah and Malhi, {Harmeet M} and Gores, {Gregory James}",
year = "2016",
month = "4",
day = "1",
doi = "10.1053/j.gastro.2015.12.037",
language = "English (US)",
volume = "150",
pages = "956--967",
journal = "Gastroenterology",
issn = "0016-5085",
publisher = "W.B. Saunders Ltd",
number = "4",

}

TY - JOUR

T1 - Lipid-Induced Signaling Causes Release of Inflammatory Extracellular Vesicles from Hepatocytes

AU - Hirsova, Petra

AU - Ibrahim, Samar C

AU - Krishnan, Anuradha

AU - Verma, Vikas K.

AU - Bronk, Steven F.

AU - Werneburg, Nathan W.

AU - Charlton, Michael R.

AU - Shah, Vijay

AU - Malhi, Harmeet M

AU - Gores, Gregory James

PY - 2016/4/1

Y1 - 2016/4/1

N2 - Background & Aims Hepatocyte cellular dysfunction and death induced by lipids and macrophage-associated inflammation are characteristics of nonalcoholic steatohepatitis (NASH). The fatty acid palmitate can activate death receptor 5 (DR5) on hepatocytes, leading to their death, but little is known about how this process contributes to macrophage-associated inflammation. We investigated whether lipid-induced DR5 signaling results in the release of extracellular vesicles (EVs) from hepatocytes, and whether these can induce an inflammatory macrophage phenotype. Methods Primary mouse and human hepatocytes and Huh7 cells were incubated with palmitate, its metabolite lysophosphatidylcholine, or diluent (control). The released EV were isolated, characterized, quantified, and applied to macrophages. C57BL/6 mice were placed on chow or a diet high in fat, fructose, and cholesterol to induce NASH. Some mice also were given the ROCK1 inhibitor fasudil; 2 weeks later, serum EVs were isolated and characterized by immunoblot and nanoparticle-tracking analyses. Livers were collected and analyzed by histology, immunohistochemistry, and quantitative polymerase chain reaction. Results Incubation of primary hepatocytes and Huh7 cells with palmitate or lysophosphatidylcholine increased their release of EVs, compared with control cells. This release was reduced by inactivating mediators of the DR5 signaling pathway or rho-associated, coiled-coil-containing protein kinase 1 (ROCK1) inhibition. Hepatocyte-derived EVs contained tumor necrosis factor-related apoptosis-inducing ligand and induced expression of interleukin 1β and interleukin 6 messenger RNAs in mouse bone marrow-derived macrophages. Activation of macrophages required DR5 and receptor-interacting protein kinase 1. Administration of the ROCK1 inhibitor fasudil to mice with NASH reduced serum levels of EVs; this reduction was associated with decreased liver injury, inflammation, and fibrosis. Conclusions Lipids, which stimulate DR5, induce release of hepatocyte EVs, which activate an inflammatory phenotype in macrophages. Strategies to inhibit ROCK1-dependent release of EVs by hepatocytes might be developed for the treatment of patients with NASH.

AB - Background & Aims Hepatocyte cellular dysfunction and death induced by lipids and macrophage-associated inflammation are characteristics of nonalcoholic steatohepatitis (NASH). The fatty acid palmitate can activate death receptor 5 (DR5) on hepatocytes, leading to their death, but little is known about how this process contributes to macrophage-associated inflammation. We investigated whether lipid-induced DR5 signaling results in the release of extracellular vesicles (EVs) from hepatocytes, and whether these can induce an inflammatory macrophage phenotype. Methods Primary mouse and human hepatocytes and Huh7 cells were incubated with palmitate, its metabolite lysophosphatidylcholine, or diluent (control). The released EV were isolated, characterized, quantified, and applied to macrophages. C57BL/6 mice were placed on chow or a diet high in fat, fructose, and cholesterol to induce NASH. Some mice also were given the ROCK1 inhibitor fasudil; 2 weeks later, serum EVs were isolated and characterized by immunoblot and nanoparticle-tracking analyses. Livers were collected and analyzed by histology, immunohistochemistry, and quantitative polymerase chain reaction. Results Incubation of primary hepatocytes and Huh7 cells with palmitate or lysophosphatidylcholine increased their release of EVs, compared with control cells. This release was reduced by inactivating mediators of the DR5 signaling pathway or rho-associated, coiled-coil-containing protein kinase 1 (ROCK1) inhibition. Hepatocyte-derived EVs contained tumor necrosis factor-related apoptosis-inducing ligand and induced expression of interleukin 1β and interleukin 6 messenger RNAs in mouse bone marrow-derived macrophages. Activation of macrophages required DR5 and receptor-interacting protein kinase 1. Administration of the ROCK1 inhibitor fasudil to mice with NASH reduced serum levels of EVs; this reduction was associated with decreased liver injury, inflammation, and fibrosis. Conclusions Lipids, which stimulate DR5, induce release of hepatocyte EVs, which activate an inflammatory phenotype in macrophages. Strategies to inhibit ROCK1-dependent release of EVs by hepatocytes might be developed for the treatment of patients with NASH.

KW - Cell Death

KW - Exosomes

KW - Lipotoxic

KW - Microvesicles

UR - http://www.scopus.com/inward/record.url?scp=84975747692&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84975747692&partnerID=8YFLogxK

U2 - 10.1053/j.gastro.2015.12.037

DO - 10.1053/j.gastro.2015.12.037

M3 - Article

C2 - 26764184

AN - SCOPUS:84975747692

VL - 150

SP - 956

EP - 967

JO - Gastroenterology

JF - Gastroenterology

SN - 0016-5085

IS - 4

ER -