Fibrin(ogen) drives repair after acetaminophen-induced liver injury via leukocyte αMβ2 integrin-dependent upregulation of Mmp12

Abstract

Background & aims Acetaminophen (APAP)-induced liver injury is coupled to activation of the blood coagulation cascade and fibrin(ogen) accumulation within APAP-injured livers of experimental mice. We sought to define the precise role of fibrin(ogen) deposition in APAP-induced liver injury and repair. Methods Fasted mice were injected with 300 mg/kg APAP i.p. and evaluated various times later. Results In wild-type mice APAP overdose increased intrahepatic levels of high molecular weight cross-linked fibrin(ogen). Anticoagulation reduced early APAP hepatotoxicity (6 hours), but surprisingly, increased hepatic injury at 24 hours, implying a protective role for coagulation at the onset of repair. Complete fibrin(ogen) deficiency delayed liver repair after APAP overdose, evidenced by a reduction of proliferating hepatocytes (24 hours) and unresolved hepatocellular necrosis (48 and 72 hours). Mutant mice with fibrin(ogen) incapable of binding leukocyte αMβ2 integrin (Fibγ390-396A mice) had decreased hepatocyte proliferation and increases in multiple indices of liver injury, suggesting a mechanism related to fibrin(ogen)-leukocyte interaction. Induction of the macrophage-associated gene, matrix metalloproteinase 12 (Mmp12), was dramatically reduced in APAP-treated Fibγ390-396A mice, and mice lacking Mmp12 displayed exacerbated APAP-induced liver injury, resembling Fibγ390-396A mice. In contrast, administration of the αMβ2 integrin allosteric agonist leukadherin-1 enhanced hepatic MMP12 mRNA and reduced necrosis in APAP-treated mice. Further, administration of recombinant MMP12 protein to APAP-treated Fibγ390-396A mice restored hepatocyte proliferation. Conclusions Collectively, these studies highlight an entirely novel pathway of liver repair after APAP overdose, mediated by fibrin(ogen)-αMβ2 integrin engagement and demonstrate for the first time a protective role of Mmp12 expression after APAP overdose.

Intrahepatic fibrin(ogen) deposition drives liver regeneration after partial hepatectomy in mice and humans

“…For example, fibrin(ogen) engagement of the integrin a M b 2 is a catalyst for leukocyte-driven repair of the liver after acetaminophen overdose. 39 Leukocytes are recruited to the liver remnant in mice undergoing PHx, and liver regeneration is delayed in leukocytopenic mice. 40 Thus, it is conceivable that fibrin(ogen)leukocyte interactions promote regeneration after PHx, as in toxic liver injury.…”

“…40 Thus, it is conceivable that fibrin(ogen)leukocyte interactions promote regeneration after PHx, as in toxic liver injury. 39 Alternatively, fibrin(ogen) may be required to promote leukocyte-directed platelet recruitment, or vice versa, after PHx. Although the interaction between platelets and leukocytes in the setting of PHx has not been studied extensively, in other models, platelets form a surface for leukocytes adhesion, and the interaction between these 2 cell types can facilitate liver repair.…”

Von Willebrand factor deficiency reduces liver fibrosis in mice

“…Hematoxylin and eosin (H&E), sirius red, alpha-smooth muscle actin (α-SMA), proliferating cell nuclear antigen (PCNA) and type I collagen stains were performed and analyzed as described previously (Sullivan et al , 2010; Joshi et al , 2016; Kopec et al , 2016). Necrosis area was calculated as described previously (Joshi et al , 2016).…”

Thrombin promotes diet-induced obesity through fibrin-driven inflammation

“…To assess WAT levels of cross-linked high-molecular weight fibrin(ogen), 100 mg of eWAT was homogenized in 8 M urea, 40 mM DTT, 12.5 mM EDTA based on protocols outlined previously (23,80), rotated end over end in a 60°C incubator for 2 hours, and incubated stationary at 60°C overnight (~15 hours). Samples were collected by centrifugation and resolved on Wes 66-to 440-kDa 25-microcapillary gels (Protein Simple).…”