Design, Synthesis, and Pharmacological Evaluation of Spiro[carbazole-3,3'-pyrrolidine] Derivatives as cGAS Inhibitors for Treatment of Acute Lung Injury.

Overactivation of cyclic GMP-AMP synthase (cGAS) is implicated in the occurrence of many inflammatory and autoimmune diseases, and inhibition of cGAS with a specific inhibitor has been proposed as a potential therapeutic strategy. However, only a few low-potency cGAS inhibitors have been reported, and few are suitable for clinical investigation. As a continuation of our structural optimization on the reported cGAS inhibitor 6 (G140), we developed a series of spiro[carbazole-3,3'-pyrrolidine] derivatives bearing a unique 2-azaspiro[4.5]decane structural motif, among which compound 30d-S was identified with high cellular effects against cGAS. This compound showed improved plasma exposure, lower clearance, and an oral bioavailability of 35% in rats. Moreover, in the LPS-induced acute lung injury (ALI) mice model, oral administration of compound 30d-S at 30 mg/kg markedly reduced lung inflammation and alleviated histopathological changes. These results confirm that 30d-S is a new efficacious cGAS inhibitor and is worthy of further investigation.

RIPK1 inhibitor ameliorates pulmonary injury by modulating the function of neutrophils and vascular endothelial cells.

Acute lung injury (ALI) is an acute and progressive hypoxic respiratory failure that could progress to acute respiratory distress syndrome (ARDS) with a high mortality rate, thus immediate medical attention and supportive care are necessary. The pathophysiology of ALI is characterized by the disruption of the alveolar-capillary barrier and activation of neutrophils, leading to lung tissue damage. The receptor-interacting protein kinase 1 (RIPK1) has emerged as a promising target for the treatment of multiple inflammatory diseases, but the role of RIPK1 in the ALI remains poorly understood. In this study, we aimed to figure out the pathological role of RIPK1 in ALI, especially in the pulmonary immune microenvironment involving neutrophils and endothelial cells. In vivo experiments showed that RIPK1 inhibitor protected against lipopolysaccharide (LPS)-induced lung injury in mouse models, with reduced neutrophils and monocytes infiltration in the lungs. Further studies demonstrated that, besides the inhibitory action on necroptosis, RIPK1 inhibitor directly suppressed reactive oxygen species (ROS) generation and inflammatory cytokines secretion from neutrophils. Furthermore, RIPK1 inhibition maintains the barrier function in TNF-α-primed vascular endothelial cells and prevents their activation induced by the supernatant from LPS-stimulated neutrophils. Mechanistically, the aforementioned effects of RIPK1 inhibitor are associated with the NF-κB signaling pathway, which is partially independent of necroptosis inhibition. These results provide new evidence that RIPK1 inhibitor directly regulates the function of neutrophils and endothelial cells, as well as interferes with the interactions between these two cell types, therefore contributing to a better understanding of RIPK1 in ALI and providing a potential avenue for future therapeutic interventions.

The anti-hyperlipidemic effects of Poria cocos (Schw.) Wolf extract: Modulating cholesterol homeostasis in hepatocytes via PPARα pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Poria cocos (Schw.) Wolf (Polyporaceae, P.cocos), which is born on the pine root, has a history of more than two thousand years of medicine in China. P.cocos was first recorded in the Shennong's Herbal Classic, studies have proved its lipid-lowering effect. AIM OF STUDY: The aim of study was to investigate the underlying mechanism of P.cocos extract on hyperlipidemia. MATERIALS AND METHODS: Male Sprague-Dawley (SD) rats aged 9-12 weeks were intraperitoneally (IP) injected with Triton-WR 1339 to establish an acute hyperlipidemia model. At 0 h and 20 h after the model was established, low and high doses of P.cocos extract or simvastatin were given twice. After 48 h, the rats were sacrificed, and liver and serum samples were collected for analysis. The cell model was constructed by treating L02 cells with 1% fat emulsion-10% FBS-RPMI 1640 medium for 48 h. At the same time, low and high doses of P.cocos extract and simvastatin were administered. Oil red O staining was used to evaluate the lipid accumulation in the cells, and H&E staining was used to evaluate the liver lesions of rats. Real-time quantitative PCR and western blotting were used to detect the expressions of lipid metabolism-related genes. RESULTS: P.cocos extract relieved lipid accumulation in vitro and alleviated hyperlipidemia in vivo. Both gene and protein expressions of peroxisome proliferator-activated receptor α (PPARα) were shown to be up-regulated by P.cocos extract. Additionally, P.cocos extract down-regulated the expressions of fatty acid synthesis-related genes sterol regulatory element-binding protein-1 (SREBP-1), Acetyl-CoA Carboxylase 1 (ACC1) and fatty acid synthase (FAS), while up-regulated the expressions of cholesterol metabolism-related genes liver X receptor-α (LXRα), ATP-binding cassette transporter A1 (ABCA1), cholesterol 7alpha-hydroxylase (CYP7A1) and low density lipoprotein receptor (LDLR), which were reversed by the treatment with the PPARα inhibitor GW6471. CONCLUSION: P.cocos extract ameliorates hyperlipidemia and lipid accumulation by regulating cholesterol homeostasis in hepatocytes through PPARα pathway. This study provides evidence that supplementation with P.cocos extract could be a potential strategy for the treatment of hyperlipidemia.

Atranorin inhibits NLRP3 inflammasome activation by targeting ASC and protects NLRP3 inflammasome-driven diseases.

Aberrant NLRP3 activation has been implicated in the pathogenesis of numerous inflammation-associated diseases. However, no small molecular inhibitor that directly targets NLRP3 inflammasome has been approved so far. In this study, we show that Atranorin (C19H18O8), the secondary metabolites of lichen family, effectively prevents NLRP3 inflammasome activation in macrophages and dendritic cells. Mechanistically, Atranorin inhibits NLRP3 activation induced cytokine secretion and cell pyroptosis through binding to ASC protein directly and therefore restraining ASC oligomerization. The pharmacological effect of Atranorin is evaluated in NLRP3 inflammasome-driven disease models. Atranorin lowers serum IL-1ß and IL-18 levels in LPS induced mice acute inflammation model. Also, Atranorin protects against MSU crystal induced mice gouty arthritis model and lowers ankle IL-1ß level. Moreover, Atranorin ameliorates intestinal inflammation and epithelial barrier dysfunction in DSS induced mice ulcerative colitis and inhibits NLRP3 inflammasome activation in colon. Altogether, our study identifies Atranorin as a novel NLRP3 inhibitor that targets ASC protein and highlights the potential therapeutic effects of Atranorin in NLRP3 inflammasome-driven diseases including acute inflammation, gouty arthritis and ulcerative colitis.