NLRP3 inflammasome blockade reduces liver inflammation and fibrosis in experimental NASH in mice.
NOD-like receptor protein 3 (NLRP3) inflammasome activation occurs in Non-alcoholic fatty liver disease (NAFLD). We used the first small molecule NLRP3 inhibitor, MCC950, to test whether inflammasome blockade alters inflammatory recruitment and liver fibrosis in two murine models of steatohepatitis.



We fed foz/foz and wild-type mice an atherogenic diet for 16weeks, gavaged MCC950 or vehicle until 24weeks, then determined NAFLD phenotype. In mice fed an methionine/choline deficient (MCD) diet, we gavaged MCC950 or vehicle for 6weeks and determined the effects on liver fibrosis.



In vehicle-treated foz/foz mice, hepatic expression of NLRP3, pro-IL-1β, active caspase-1 and IL-1β increased at 24weeks, in association with cholesterol crystal formation and NASH pathology; plasma IL-1β, IL-6, MCP-1, ALT/AST all increased. MCC950 treatment normalized hepatic caspase 1 and IL-1β expression, plasma IL-1β, MCP-1 and IL-6, lowered ALT/AST, and reduced the severity of liver inflammation including designation as NASH pathology, and liver fibrosis. In vitro, cholesterol crystals activated Kupffer cells and macrophages to release IL-1β; MCC950 abolished this, and the associated neutrophil migration. MCD diet-fed mice developed fibrotic steatohepatitis; MCC950 suppressed the increase in hepatic caspase 1 and IL-1β, lowered numbers of macrophages and neutrophils in the liver, and improved liver fibrosis.



MCC950, an NLRP3 selective inhibitor, improved NAFLD pathology and fibrosis in obese diabetic mice. This is potentially attributable to the blockade of cholesterol crystal-mediated NLRP3 activation in myeloid cells. MCC950 reduced liver fibrosis in MCD-fed mice. Targeting NLRP3 is a logical direction in pharmacotherapy of NASH.



Fatty liver disease caused by being overweight with diabetes and a high risk of heart attack, termed non-alcoholic steatohepatitis (NASH), is the most common serious liver disease with no current treatment. There could be several causes of inflammation in NASH, but activation of a protein scaffold within cells termed the inflammasome (NLRP3) has been suggested to play a role. Here we show that cholesterol crystals could be one pathway to activate the inflammasome in NASH. We used a drug called MCC950, which has already been shown to block NLRP3 activation, in an attempt to reduce liver injury in NASH. This drug partly reversed liver inflammation, particularly in obese diabetic mice that most closely resembles the human context of NASH. In addition, such dampening of liver inflammation in NASH achieved with MCC950 partly reversed liver scarring, the process that links NASH to the development of cirrhosis.
Liver Research Group, ANU Medical School, Australian National University at The Canberra Hospital, Garran, ACT, Australia.
Auvro R
AR
Mridha
Department of Internal Medicine III, RWTH-Aachen University Hospital, Aachen, Germany; Department of Pediatrics, University of California - San Diego, La Jolla, San Diego, CA, United States.
Alexander
A
Wree
Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia.
Avril A B
AAB
Robertson
Department of Pathology, University of Washington, Seattle, WA, United States.
Matthew M
MM
Yeh
Department of Pediatrics, University of California - San Diego, La Jolla, San Diego, CA, United States.
Casey D
CD
Johnson
Liver Research Group, ANU Medical School, Australian National University at The Canberra Hospital, Garran, ACT, Australia.
Derrick M
DM
Van Rooyen
Liver Research Group, ANU Medical School, Australian National University at The Canberra Hospital, Garran, ACT, Australia.
Fahrettin
F
Haczeyni
Liver Research Group, ANU Medical School, Australian National University at The Canberra Hospital, Garran, ACT, Australia.
Narci C-H
NC
Teoh
Department of Gastroenterology and Hepatology, Veterans Affairs Puget Sound Health Care System and University of Washington, Seattle, WA, United States.
Christopher
C
Savard
Department of Gastroenterology and Hepatology, Veterans Affairs Puget Sound Health Care System and University of Washington, Seattle, WA, United States.
George N
GN
Ioannou
The Walter and Eliza Hall Institute, Parkville, VIC, Australia.
Seth L
SL
Masters
Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia.
Kate
K
Schroder
Institute for Molecular Bioscience, University of Queensland, St Lucia, QLD, Australia.
Matthew A
MA
Cooper
Department of Pediatrics, University of California - San Diego, La Jolla, San Diego, CA, United States.
Ariel E
AE
Feldstein
Liver Research Group, ANU Medical School, Australian National University at The Canberra Hospital, Garran, ACT, Australia. Electronic address: geoff.farrell@anu.edu.au.
Geoffrey C
GC
Farrell
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D005663:Furans; D006505:Hepatitis / Q000517:prevention & control*; D006576:Heterocyclic Compounds, 4 or More Rings / Q000627:therapeutic use*; D007192:Indenes; D053583:Interleukin-1beta / Q000097:blood; D008106:Liver Cirrhosis, Experimental / Q000517:prevention & control*; D051379:Mice; D016328:NF-kappa B / Q000502:physiology; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein / Q000037:antagonists & inhibitors* / Q000502:physiology; D065626:Non-alcoholic Fatty Liver Disease / Q000150:complications / Q000188:drug therapy*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013449:Sulfonamides; D013450:Sulfones / Q000627:therapeutic use*
D005663:Furans; D006576:Heterocyclic Compounds, 4 or More Rings; D007192:Indenes; D053583:Interleukin-1beta; D016328:NF-kappa B; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C492716:Nlrp3 protein, mouse; D017382:Reactive Oxygen Species; D013449:Sulfonamides; D013450:Sulfones; C000597426:N-(1,2,3,5,6,7-hexahydro-S-indacen-4-ylcarbamoyl)-4-(2-hydroxy-2-propanyl)-2-furansulfonamide
Cholesterol crystals; Diet, atherogenic; Fibrosis; Hepatocytes; Inflammasomes; Interleukin-1β; Kupffer cells; Methionine; NAFLD; NLR proteins; NLRP3