An ACAT-1Inhibitor, K-604, Ameliorates Hepatic Inflammation in NAFLD and NASH Models

Abstract

A high level of cholesterol activates Kupffer cells, which subsequently triggers inflammation and ultimately leads to steatohepatitis. The number of Kupffer cells correlates with the inflammatory grade of Non-Alcoholic Fatty Liver Disease (NAFLD). In this study, we studied the role of 'foamy' Kupffer cells in the nexus between inflammation and steatosis and investigated whether K-604, a selective Acyl-Coenzyme A: Cholesterol Acyltransferase-1 (ACAT-1) inhibitor ameliorates hepatic steatosis and inflammation in rodent models of NAFLD and Non-Alcoholic Steatohepatitis (NASH). Methionine-and Choline-Deficient (MCD) diet-fed KK-Ay mice, High-Fat and High-Cholesterol (HFC) diet-fed Low-Density Lipoprotein Receptor-Deficient (Ldlr(−/−)) mice and Zucker fatty rats were evaluated after 16, 16 and 12 weeks of K-604 treatment. The biochemical parameters, hepatic lipid levels, histopathological changes and gene expression levels were assessed. In the MCD dietfed KK-Ay mice, K-604 significantly improved the NASH symptoms. In the HFC diet-fed Ldlr (−/−) mice, K-604 suppressed the inflammatory gene expression and reduced the number of inflammatory foci. Moreover, K-604 decreased the area and size of foamy Kupffer cells. In the Zucker fatty rats, K-604 could also inhibit hepatic steatosis. These results indicated that K-604 acts directly on Kupffer cells and inhibits hepatic inflammation, suggesting that ACAT-1 is involved in the progression of steatohepatitis. Therefore, ACAT-1 inhibition may be a new therapeutic target for NAFLD and NASH.

Discovery of Clinical Candidate 2-(4-(2-((1H-Benzo[d]imidazol-2-yl)thio)ethyl)piperazin-1-yl)-N-(6-methyl-2,4-bis(methylthio)pyridin-3-yl)acetamide Hydrochloride [K-604], an Aqueous-Soluble Acyl-CoA:Cholesterol O-Acyltransferase-1 Inhibitor

“…Alcohol 12 was protected with tert-butyldiphenylchlorosilane in the presence of imidazole in DMF to afford the TBDPS ether, 13. (trans-(4-(Benzyloxy)methyl)cyclohexyl)methanol ( 24) was prepared from trans-1,4-cyclohexanedimethanol (23) according to the method described in a patent application. 38 Exposure of 24 to the sulfur trioxide−pyridine complex in DMSO yielded aldehyde 25, which was oxidized to carboxylic acid 26 by sodium chlorite.…”

“…ACAT-1 is ubiquitously expressed in various human tissues, predominantly in human liver (Kupffer cells), macrophages, adrenal gland, and brain tissue, whereas ACAT-2 is found in human hepatocytes and intestinal tissue. − Recently, an ACAT-1 inhibitor was highlighted in the context of drug repositioning (repurposing) for potential application in the treatment of the following diseases: (1) In multiple neurodegenerative diseases, including Alzheimer’s disease, − blocking ACAT-1 provides new benefits, such as clearance of amyloid β (Aβ) peptides and suppression of 24­( S )-hydroxycholesterol-induced neuronal-cell death. (2) In nonalcoholic steatohepatitis (NASH), progression of steatosis and liver inflammation via Kupffer cells activated by high levels of CE is involved in ACAT-1 induction. Therefore, ACAT-1 inhibition may be a new therapeutic target for the treatment of NASH.…”