title: The novel TLR9 antagonist COV08-0064 protects from ischemia/reperfusion injury in non-steatotic and steatotic mice livers.
abstract: Ischemia/reperfusion (I/R) injury constitutes a major reason for failure of liver surgeries and transplantation. I/R injury is more severe in steatotic livers and limits their use in transplantation. Here, we present a novel and selective Toll-like receptor 9 (TLR9) antagonist COV08-0064 and test its potential to protect from I/R-induced injury in normal and steatotic livers. The in vivo effects of COV08-0064 pretreatment were investigated on normal chow diet (NCD) and high fat diet (HFD)-fed mice subjected to segmental (70%) warm hepatic I/R. Also, the in vitro effects of COV08-0064 were elucidated in murine macrophages and dendritic cells. Mice on a HFD had pronouncedly greater hepatic I/R injury than mice on a NCD. COV08-0064-pretreatment to both NCD and HFD-fed mice reduced hepatic I/R injury. COV08-0064-pretreatment was associated with less production of the liver inflammatory cytokines and mediators TNF-α, IL-1β, IL-6, NLRP3, iNOS and MCP-1. These manifestations were preceded with inhibition of JNK and ERK phosphorylation and TLR9 cleavage in the liver. COV08-0064 enhanced the hepatic expression of the endogenous anti-inflammatory cytokines IL-10 and IL-1Ra at the early phase I/R injury. In vitro, COV08-0064 selectively blocked mRNA upregulation of TNF-α, IL-1β, NLRP3 and MCP-1 in macrophages and IFN-β mRNA in dendritic cells induced by the TLR9 agonist CpG-ODN. These effects were concordant with inhibition of JNK, ERK, IκBα and IKKα/β phosphorylation. In conclusion, TLR9 signaling inhibition by COV08-0064 may be an effective approach in liver surgeries including transplantation to limit I/R-injury and overcome the shortages in the donor pool by incorporating steatotic livers.
authors.affiliation: Section of Digestive Diseases, Department of Internal Medicine, Yale University, New Haven, CT 06520, USA; Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt.
authors.forename: Mohamed E
authors.initials: ME
authors.lastname: Shaker
authors.affiliation: Center for Organic Chemistry, Mallinckrodt Pharmaceuticals, St. Louis, MO 63147, USA.
authors.forename: Bobby N
authors.initials: BN
authors.lastname: Trawick
authors.affiliation: Section of Digestive Diseases, Department of Internal Medicine, Yale University, New Haven, CT 06520, USA; Section of Digestive Diseases, Department of Veterans Affairs Connecticut Healthcare, West Haven, CT 06516, USA. Electronic address: wajahat.mehal@yale.edu.
authors.forename: Wajahat Z
authors.initials: WZ
authors.lastname: Mehal
mesh_terms: D000818:Animals; D003713:Dendritic Cells / Q000187:drug effects / Q000378:metabolism; D059305:Diet, High-Fat; D005234:Fatty Liver / Q000150:complications* / Q000473:pathology; D008099:Liver / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008111:Liver Function Tests; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D015427:Reperfusion Injury / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D051217:Toll-Like Receptor 9 / Q000037:antagonists & inhibitors*
chemical_list: C000619250:6-N-methylnaltrexamine; C495370:Tlr9 protein, mouse; D051217:Toll-Like Receptor 9; D009271:Naltrexone
keywords: Liver ischemia/reperfusion; Liver transplantation; Steatosis; TLR9