Structure-Based Design of Novel Alkynyl Thio-Benzoxazepinone Receptor-Interacting Protein Kinase-1 Inhibitors: Extending the Chemical Space from the Allosteric to ATP Binding Pockets.

Systemic inflammatory response syndrome (SIRS), characterized by severe systemic inflammation, represents a major cause of health loss, potentially leading to multiple organ failure, shock, and death. Exploring potent RIPK1 inhibitors is an effective therapeutic strategy for SIRS. Recently, we described thio-benzoxazepinones as novel RIPK1 inhibitors and confirmed their anti-inflammatory activity. Herein, we further synthesized novel thio-benzoxazepinones by introducing substitutions on the benzene ring by an alkynyl bridge in order to extend the chemical space from the RIPK1 allosteric to ATP binding pockets. The in vitro cell and kinase assays found that compounds 2 and 29 showed highly potent activity against necroptosis (EC50 = 3.7 and 3.2 nM) and high RIPK1 inhibitory activity (Kd = 9.7 and 70 nM). Prominently, these two analogues possessed better in vivo anti-inflammatory effects than the clinical candidate GSK'772 and effectively blocked hypothermia and deaths in a TNFα-induced SIRS model.

Discovery of a Trifluoromethoxy Cyclopentanone Benzothiazole Receptor-Interacting Protein Kinase 1 Inhibitor as the Treatment for Alzheimer's Disease.

Receptor-interacting protein kinase 1 (RIPK1) contributes to a broad set of inflammations and necroptosis in human diseases, which also plays an important role in the pathogenesis of Alzheimer's disease (AD). The inhibition of RIPK1 could be a novel strategy to improve cognitive function. SZM679, a highly specific RIPK1 inhibitor (Kd,RIPK1 = 8.6 nM, Kd,RIPK3 > 5000 nM), was developed by our group with superior high antinecroptotic activity (EC50 = 2 nM), and investigated to completely reverse the tumor necrosis factor-induced systemic inflammatory response syndrome. In a streptozocin-induced AD-like mouse model, behavioral tests showed that SZM679 apparently ameliorated learning and memory dysfunction. Nissl staining revealed that SZM679 improved neuronal loss. Moreover, the Tau hyperphosphorylation, neuroinflammation, and the RIPK1 phosphorylation level in the hippocampus and cortex were significantly decreased in the SZM679-treated group. Collectively, SZM679 represents a promising lead structure for the discovery of novel RIPK1 inhibitory anti-AD agents.

Rosemary Extracts Upregulate Nrf2, Sestrin2, and MRP2 Protein Level in Human Hepatoma HepG2 Cells.

In the past few decades, the incidence of liver cancer has been rapidly rising across the world. Rosemary is known to possess antioxidant activity and is used as natural antioxidant food preservative. It is proposed to have anticancer activity in treating different tumor models. In this study, we try to explore the impact of rosemary extracts on upregulating the level of Nrf2 and Nrf2-regulatory proteins, Sestrin2 and MRP2 in HepG2 cells, and to speculate its potential mechanism. The anticancer activity of rosemary extract, including its polyphenolic diterpenes carnosic acid and carnosol, was evaluated to understand the potential effect on HepG2 cells. Rosemary extract, carnosic acid, and carnosol induced the expression of Sestrin2 and MRP2 associate with enhancement of Nrf2 protein level in HepG2 cells, in which carnosic acid showed most obvious effect. Although the activation pathway of Nrf2/ARE was not exactly assessed, it can be assumed that the enhancement of expression of Sestrin2 and MRP2 may result from upregulation of Nrf2.