Britannin as a novel NLRP3 inhibitor, suppresses inflammasome activation in macrophages and alleviates NLRP3-related diseases in mice.

Overactivation of the NLRP3 inflammasomes induces production of pro-inflammatory cytokines and drives pathological processes. Pharmacological inhibition of NLRP3 is an explicit strategy for the treatment of inflammatory diseases. Thus far no drug specifically targeting NLRP3 has been approved by the FDA for clinical use. This study was aimed to discover novel NLRP3 inhibitors that could suppress NLRP3-mediated pyroptosis. We screened 95 natural products from our in-house library for their inhibitory activity on IL-1ß secretion in LPS + ATP-challenged BMDMs, found that Britannin exerted the most potent inhibitory effect with an IC50 value of 3.630 µM. We showed that Britannin (1, 5, 10 µM) dose-dependently inhibited secretion of the cleaved Caspase-1 (p20) and the mature IL-1ß, and suppressed NLRP3-mediated pyroptosis in both murine and human macrophages. We demonstrated that Britannin specifically inhibited the activation step of NLRP3 inflammasome in BMDMs via interrupting the assembly step, especially the interaction between NLRP3 and NEK7. We revealed that Britannin directly bound to NLRP3 NACHT domain at Arg335 and Gly271. Moreover, Britannin suppressed NLRP3 activation in an ATPase-independent way, suggesting it as a lead compound for design and development of novel NLRP3 inhibitors. In mouse models of MSU-induced gouty arthritis and LPS-induced acute lung injury (ALI), administration of Britannin (20 mg/kg, i.p.) significantly alleviated NLRP3-mediated inflammation; the therapeutic effects of Britannin were dismissed by NLRP3 knockout. In conclusion, Britannin is an effective natural NLRP3 inhibitor and a potential lead compound for the development of drugs targeting NLRP3.

Descending Necrotizing Mediastinitis: Analysis of 9 Cases in Our Hospital.

OBJECTIVES: Descending necrotizing mediastinitis (DNM) is a serious and progressive infection involving the neck and chest and with high mortality if not treated quickly and properly. The aim of this study is to share our practices for managing this condition. METHODS: We retrospectively evaluated 9 patients diagnosed with DNM in our hospital between January 2006 and October 2019. Age, gender, origin of infection, length of hospital stay, microorganisms present, type of surgical treatment, and clinical outcomes were reviewed. RESULTS: All patients underwent surgery to drain neck and mediastinal secretions and collections. Three (33.3%) patients were treated with transcervical drainage alone, and 6 (66.7%) patients were treated with combined transcervical and transthoracic drainage. Reoperations were reported in 3 (33.3%) cases. The average length of hospital stay was 22.78 ± 10.05 days (range: 9-40 days). The average length of intensive care unit stay was 6.44 ± 10.10 days (range: 0-25 days). There were no in-hospital deaths, and all patients were discharged home with good outcomes. CONCLUSIONS: To improve the prognosis of DNM, we suggest early and adequate debridement of all affected areas along with the proper use of antibiotics. A multidisciplinary approach involving both cardiothoracic and ENT surgeons is also required.

Antitumor treatment efficacy by targeting epidermal growth factor receptor and vascular endothelial growth factor receptor-2 in an orthotopic human glioblastoma model.

Using an orthotopic intracerebral model from our established HM55-BGIV-101 tumor line, we investigated the antitumor effect on the angiogenesis and growth of human glioblastoma after treatment with monoclonal antibody DC101 against the vascular endothelial growth factor receptor-2 and monoclonal antibody C225 against the epidermal growth factor receptor. Nude mice bearing intracerebral glioblastoma xenografts were treated intraperitoneally with DC101 and C225 either alone or in combination. Histopathological analysis of solid tumor volume, satellite tumor number, microvessel density, tumor cell proliferation, and apoptosis was performed. In the DC101-treated group, solid tumor volume and microvessel density were reduced by 59.7 and 64%, respectively; tumor cell proliferative activity was reduced by 53.2% and the apoptotic index (AI) was increased by 66.7%; satellite tumor number was enhanced by 84.4%. C225 alone reduced satellite tumor number by 43.3%, but had no effect on solid tumor volume, microvessel density, tumor cell proliferation, and apoptosis. C225 combined with DC101 not only reduced solid tumor volume, microvessel density, tumor cell proliferative activity, and increased AI, but also reduced satellite tumor number. Inhibition of angiogenesis achieved by DC101 can cause increased tumor cell invasiveness. In our studies this increased tumor cell invasiveness was inhibited simultaneously by C225, which provides a theoretical basis for treatment of glioblastoma by the method of combining drugs with different pharmacological activity.

Enhanced cancer therapy with the combination of EGFR and VEGFR-2 targeting in an orthotopic glioblastoma model.

Using an orthotopic glioblastoma model, we investigated the activity of the combination of monoclonal antibody DC101 against vascular endothelial growth factor receptor-2 (VEGFR-2) and monoclonal antibody C225 against epidermal growth factor receptor (EGFR). Nude mice bearing intracerebral glioblastoma xenografts were administered either DC101 or C225, or the combination via intraperitoneal (i.p.) injection. Histopathological analysis of solid tumor volume, microvessel density, tumor cell proliferation and apoptosis were performed. In the DC101-treated group, solid tumor volume and microvessel density were reduced by 59.7% and 64%, respectively. The tumor cell proliferation level was reduced by 53.2% and tumor cell apoptosis was increased by 66.7% but there was enhanced tumor cell invasiveness. C225 alone reduced the invasiveness of tumor tissue, but had no effect on solid tumor growth, microvessel density, tumor cell proliferation or apoptosis. The combination cancer therapy with C225 and DC101 enhanced tumor treatment with reduced tumor volume, microvessel density, tumor cell proliferation level, and increased cancer cell apoptosis, while decreasing tumor cell invasiveness.