Rho-associated protein kinase 1 inhibition in hepatocytes attenuates nonalcoholic steatohepatitis.

BACKGROUND: NASH is the progressive form of NAFLD characterized by lipotoxicity, hepatocyte injury, tissue inflammation, and fibrosis. Previously, Rho-associated protein kinase (ROCK) 1 has been implicated in lipotoxic signaling in hepatocytes in vitro and high-fat diet-induced lipogenesis in vivo. However, whether ROCK1 plays a role in liver inflammation and fibrosis during NASH is unclear. Here, we hypothesized that pathogenic activation of ROCK1 promotes murine NASH pathogenesis. METHODS AND RESULTS: Patients with NASH had increased hepatic ROCK1 expression compared with patients with fatty liver. Similarly, hepatic ROCK1 levels and activity were increased in mice with NASH induced by a western-like diet that is high in fat, fructose, and cholesterol (FFC). Hepatocyte-specific ROCK1 knockout mice on the FFC diet displayed a decrease in liver steatosis, hepatic cell death, liver inflammation, and fibrosis compared with littermate FFC-fed controls. Mechanistically, these effects were associated with a significant attenuation of myeloid cell recruitment. Interestingly, myeloid cell-specific ROCK1 deletion did not affect NASH development in FFC-fed mice. To explore the therapeutic opportunities, mice with established NASH received ROCKi, a novel small molecule kinase inhibitor of ROCK1/2, which preferentially accumulates in liver tissue. ROCK inhibitor treatment ameliorated insulin resistance and decreased liver injury, inflammation, and fibrosis. CONCLUSIONS: Genetic or pharmacologic inhibition of ROCK1 activity attenuates murine NASH, suggesting that ROCK1 may be a therapeutic target for treating human NASH.

Inhibition of Bruton's TK regulates macrophage NF-κB and NLRP3 inflammasome activation in metabolic inflammation.

BACKGROUND AND PURPOSE: There are no medications currently available to treat metabolic inflammation. Bruton's tyrosine kinase (BTK) is highly expressed in monocytes and macrophages and regulates NF-κB and NLRP3 inflammasome activity; both propagate metabolic inflammation in diet-induced obesity. EXPERIMENTAL APPROACH: Using an in vivo model of chronic inflammation, high-fat diet (HFD) feeding, in male C57BL/6J mice and in vitro assays in primary murine and human macrophages, we investigated if ibrutinib, an FDA approved BTK inhibitor, may represent a novel anti-inflammatory medication to treat metabolic inflammation. KEY RESULTS: HFD-feeding was associated with increased BTK expression and activation, which was significantly correlated with monocyte/macrophage accumulation in the liver, adipose tissue, and kidney. Ibrutinib treatment to HFD-fed mice inhibited the activation of BTK and reduced monocyte/macrophage recruitment to the liver, adipose tissue, and kidney. Ibrutinib treatment to HFD-fed mice decreased the activation of NF-κB and the NLRP3 inflammasome. As a result, ibrutinib treated mice fed HFD had improved glycaemic control through restored signalling by the IRS-1/Akt/GSK-3ß pathway, protecting mice against the development of hepatosteatosis and proteinuria. We show that BTK regulates NF-κB and the NLRP3 inflammasome specifically in primary murine and human macrophages, the in vivo cellular target of ibrutinib. CONCLUSION AND IMPLICATIONS: We provide "proof of concept" evidence that BTK is a novel therapeutic target for the treatment of diet-induced metabolic inflammation and ibrutinib may be a candidate for drug repurposing as an anti-inflammatory agent for the treatment of metabolic inflammation in T2D and microvascular disease.

Reaction of Glyconitriles with Organometallic Reagents: Access to Acyl ß-C-Glycosides.

A new strategy for the synthesis of acyl ß-C-glycosides is described. The reactivity of glyconitriles toward organometallic reagents such as organomagnesium or organolithium derivatives was studied, affording acyl ß-C-glycosides in moderate to good yields. In this study, glycal formation was efficiently prevented by deprotonating the hydroxyl group in position 2 of the glyconitriles during the process.