BackgroundSpinal cord injury (SCI) is a devastating disease, which results in tissue loss and neurologic dysfunction. NLRP3 inflammasome plays an important role in the mechanism of diverse diseases. However, no studies have demonstrated the role of NLRP3 inflammasome and the effects of NLRP3 inflammasome inhibitors in a mouse model of SCI. We investigated whether inhibition of NLRP3 inflammasome activation by the pharmacologic inhibitor BAY 11-7082 or A438079 could exert neuroprotective effects in a mouse model of SCI.MethodsSCI was performed using an aneurysm clip with a closing force of 30 g at the level of the T6-T7 vertebra for 1 min. Motor recovery was evaluated by an open-field test. Neuronal death was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling and Nissl staining. Mitochondrial dysfunction was determined by quantitative real-time polymerase chain reaction (qPCR), western blot, and detection of mitochondrial membrane potential level. Microglia/macrophage activation and astrocytic response were evaluated by immunofluorescence labeling.ResultsInhibition of NLRP3 inflammasome activation by pharmacologic inhibitor BAY 11-7082 or A438079 reduced neuronal death, attenuated spinal cord anatomic damage, and promoted motor recovery. Furthermore, BAY 11-7082 or A438079 directly attenuated the levels of NLRP3 inflammasome and proinflammatory cytokines. Moreover, BAY 11-7082 or A438079 alleviated microglia/macrophage activation, neutrophils infiltration, and reactive gliosis, as well as mitochondrial dysfunction.ConclusionsCollectively, our results demonstrate that pharmacologic suppression of NLRP3 inflammasome activation controls neuroinflammation, attenuates mitochondrial dysfunction, alleviates the severity of spinal cord damage, and improves neurological recovery after SCI. These data strongly indicate that the NLRP3 inflammasome is a vital contributor to the secondary damage of SCI in mice.

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MicroRNAs (miRNAs) play critical roles in human cancers including osteosarcoma (OS). miR-92a has been found to be a cancer-related miRNA in many cancer types and it is upregulated in OS cell lines. However, the expression and biological function of miR-92a in OS have not been investigated. In this study, we showed that miR-92a expression was increased in OS tissues, and its high expression was correlated with clinical stage, T classification and histological differentiation. Furthermore, patients with high expression of miR-92a had a significantly poorer survival rate. Functionally, miR-92a overexpression promoted the proliferation and cell cycle progression, and inhibited apoptosis in MG-63 cells. While inhibition of miR-92a showed contrary effects with reduced proliferation, cell cycle arrest at G1 phase and increased apoptosis in U2OS cells. Moreover, we confirmed that miR-92a inhibition reversed the tumor growth of OS cells in nude mice. Phosphatase and tensin homolog (PTEN), a well-known tumor suppressor, was confirmed to be the direct downstream target of miR-92a in OS. Notably, miR-92a consequently regulated the expression of the downstream targets of PTEN/AKT signaling pathway including p-Akt(Ser473), mTOR, p-p27(Thr157) and p-MDM2(Ser166). Furthermore, PTEN knockdown abrogated the functional effects of miR-92a silencing on the proliferation, apoptosis and cell cycle progression in OS cells. Thus, miR-92a that exerts an oncogenic role by targeting PTEN/AKT pathway in OS potentially acts as a biomarker and drug-target.

A-68930 can attenuate tissue damage and improve neurological function recovery, and the mechanism may be related to the inhibition of NLRP3 inflammasome activation.