A novel mouse model of depletion of stellate cells clarifies their role in ischemia/reperfusion- and endotoxin-induced acute liver injury.
OBJECTIVE
Hepatic stellate cells (HSCs) that express glial fibrillary acidic protein (GFAP) are located between the sinusoidal endothelial cells and hepatocytes. HSCs are activated during liver injury and cause hepatic fibrosis by producing excessive extracellular matrix. HSCs also produce many growth factors, chemokines and cytokines, and thus may play an important role in acute liver injury. However, this function has not been clarified due to unavailability of a model, in which HSCs are depleted from the normal liver.


METHODS
We treated mice expressing HSV-thymidine kinase under the GFAP promoter (GFAP-Tg) with 3 consecutive (3 days apart) CCl4 (0.16 μl/g; ip) injections to stimulate HSCs to enter the cell cycle and proliferate. This was followed by 10-day ganciclovir (40 μg/g/day; ip) treatment, which is expected to eliminate actively proliferating HSCs. Mice were then subjected to hepatic ischemia/reperfusion (I/R) or endotoxin treatment.


RESULTS
CCl4/ganciclovir treatment caused depletion of the majority of HSCs (about 64-72%), while the liver recovered from the initial CCl4-induced injury (confirmed by histology, serum ALT and neutrophil infiltration). The magnitude of hepatic injury due to I/R or endotoxemia (determined by histopathology and serum ALT) was lower in HSC-depleted mice. Their hepatic expression of TNF-α, neutrophil chemoattractant CXCL1 and endothelin-A receptor also was significantly lower than the control mice.


CONCLUSIONS
HSCs play an important role both in I/R- and endotoxin-induced acute hepatocyte injury, with TNF-α and endothelin-1 as important mediators of these effects.
Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213.
Rachel K
RK
Stewart
Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213.|Department of Surgery University of Cincinnati and Cincinnati VA Medical Center, Cincinnati, OH, USA and Cincinnati Veterans Administration, Cincinnati, OH, USA.
Anil
A
Dangi
Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213.
Chao
C
Huang
Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213.
Noriko
N
Murase
Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213.
Shoko
S
Kimura
Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA.
Donna B
DB
Stolz
Department of Surgery University of Cincinnati and Cincinnati VA Medical Center, Cincinnati, OH, USA and Cincinnati Veterans Administration, Cincinnati, OH, USA.
Gregory C
GC
Wilson
Department of Surgery University of Cincinnati and Cincinnati VA Medical Center, Cincinnati, OH, USA and Cincinnati Veterans Administration, Cincinnati, OH, USA.
Alex B
AB
Lentsch
Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213.|Department of Surgery University of Cincinnati and Cincinnati VA Medical Center, Cincinnati, OH, USA and Cincinnati Veterans Administration, Cincinnati, OH, USA.|Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
Chandrashekhar R
CR
Gandhi
D000818:Animals; D002251:Carbon Tetrachloride / Q000633:toxicity; D056486:Chemical and Drug Induced Liver Injury / Q000235:genetics / Q000473:pathology / Q000503:physiopathology; D054360:Chemokine CXCL1 / Q000235:genetics; D004195:Disease Models, Animal; D019332:Endothelin-1 / Q000235:genetics; D015774:Ganciclovir / Q000633:toxicity; D015870:Gene Expression; D005904:Glial Fibrillary Acidic Protein; D055166:Hepatic Stellate Cells / Q000187:drug effects / Q000473:pathology* / Q000502:physiology*; D015850:Interleukin-6 / Q000235:genetics; D008070:Lipopolysaccharides / Q000633:toxicity; D008099:Liver / Q000293:injuries* / Q000473:pathology / Q000503:physiopathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000235:genetics; D015427:Reperfusion Injury / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology*; D013937:Thymidine Kinase / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D054360:Chemokine CXCL1; C475895:Cxcl1 protein, mouse; D019332:Endothelin-1; D005904:Glial Fibrillary Acidic Protein; D015850:Interleukin-6; D008070:Lipopolysaccharides; D009419:Nerve Tissue Proteins; D014409:Tumor Necrosis Factor-alpha; C528900:glial fibrillary astrocytic protein, mouse; D002251:Carbon Tetrachloride; D013937:Thymidine Kinase; D015774:Ganciclovir
ALT; Ab; Apoptosis; CCl(4); Depletion; ECM; ET-1; Endotoxemia; GCV; GFAP; H/E; HSC; HSV; Hepatic stellate cells; Hepatocytes; I/R; IL; IP; Injury; Ischemia/reperfusion; KCs; Kupffer cells; LPS; Lipopolysaccharide; Liver; NO; NOS; Necrosis; PBS; ROS; TK; TNF; Tg; WT; alanine aminotransferase; antibody; carbon tetrachloride; endothelin-1; extracellular matrix; ganciclovir; glial fibrillary acidic protein; hematoxylin and eosin; hepatic stellate cell; herpes simplex virus; interleukin; intraperitoneal; ischemia/reperfusion; lipopolysaccharide; nitric oxide; nitric oxide synthase; phosphate-buffered saline; qRT-PCR; quantitative real-time polymerase chain reaction; reactive oxygen species; thymidine kinase; transgenic; tumor necrosis factor; wild type