Acacetin protects against cerebral ischemia-reperfusion injury via the NLRP3 signaling pathway.

Acacetin (5,7-dihydroxy-4'-methoxyflavone), a potential neuroprotective agent, has an inhibitory effect on lipopolysaccharide-induced neuroinflammatory reactions. However, whether acacetin has an effect on inflammatory corpuscle 3 (NLRP3) after cerebral ischemia-reperfusion injury has not been fully determined. This study used an improved suture method to establish a cerebral ischemia-reperfusion injury model in C57BL/6 mice. After ischemia with middle cerebral artery occlusion for 1 hour, reperfusion with intraperitoneal injection of 25 mg/kg of acacetin (acacetin group) or an equal volume of saline (0.1 mL/10 g, middle cerebral artery occlusion group) was used to investigate the effect of acacetin on cerebral ischemia-reperfusion injury. Infarct volume and neurological function scores were determined by 2,3,5-triphenyltetrazolium chloride staining and the Zea-Longa scoring method. Compared with the middle cerebral artery occlusion group, neurological function scores and cerebral infarction volumes were significantly reduced in the acacetin group. To understand the effect of acacetin on microglia-mediated inflammatory response after cerebral ischemia-reperfusion injury, immunohistochemistry for the microglia marker calcium adapter protein ionized calcium-binding adaptor molecule 1 (Iba1) was examined in the hippocampus of ischemic brain tissue. In addition, tumor necrosis factor-α, interleukin-1ß, and interleukin-6 expression in ischemic brain tissue of mice was quantified by enzyme-linked immunosorbent assay. Expression of Iba1, tumor necrosis factor-α, interleukin-1ß and interleukin-6 was significantly lower in the acacetin group compared with the middle cerebral artery occlusion group. Western blot assay results showed that expression of Toll-like receptor 4, nuclear factor kappa B, NLRP3, procaspase-1, caspase-1, pro-interleukin-1ß, and interleukin-1ß were significantly lower in the acacetin group compared with the middle cerebral artery occlusion group. Our findings indicate that acacetin has a protective effect on cerebral ischemia-reperfusion injury, and its mechanism of action is associated with inhibition of microglia-mediated inflammation and the NLRP3 signaling pathway.

MicroRNA-126-3p suppresses cell proliferation by targeting PIK3R2 in Kaposi's sarcoma cells.

Kaposi's sarcoma is a highly vascular tumor of lymphatic endothelial origin. Many deregulated miRNAs, including miR-126-3p, have been identified in Kaposi's sarcoma tissues. miR-126-3p is the most highly endothelial-specific miRNA that regulates vascular integrity and angiogenesis. In this study, we aimed to determine the effect of miR-126-3p on Kaposi's sarcoma cells through transfection of a miRNA mimic and inhibitor. Moreover, we searched the target gene (PIK3R2) of miR-126-3p using bioinformatics software and further verified PIK3R2 using luciferase reporter assays, Real-time quantitative PCR (qRT-PCR) and western blot. The results demonstrated that miR-126-3p inhibited cell proliferation, arrested cell cycle progression, induced cell apoptosis, and inhibited cell invasion of SLK cells. The bioinformatics analysis and luciferase reporter assay revealed that PIK3R2 mRNA is a direct target of miR-126-3p. Moreover, the level of expression of the PIK3R2 gene was downregulated in SLK cells transfected with miR-126-3p siRNAs. Therefore, our data demonstrated that miR-126-3p is a tumor suppressor miRNA that acts by targeting PIK3R2 in Kaposi's sarcoma cells. These findings contribute to our understanding of the molecular mechanisms underlying Kaposi's sarcoma.

The expression profiles of microRNAs in Kaposi's sarcoma.

Kaposi's sarcoma (KS) is a multicentric angioproliferative tumor of mesenchymal origin. The molecular and biologic aspects of KS are not fully understood. MicroRNAs are non-protein-coding small RNAs in the size range 19-25 nucleotides (nt) that play important roles in biological processes, including cellular differentiation, proliferation, and death. We performed a miRNA microarray analysis by detecting six paired KS and matched adjacent healthy tissues using the 7th generation of miRCURY(TM) LNA Array (v.18.0) (Exiqon) containing 3100 capture probes. We selected 10 significant differentially expressed miRNAs, which were confirmed by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) in 18 paired KS and matched adjacent healthy tissue specimens. We also investigated the associations between clinical features and miRNA expression. Among the 3100 human miRNA probes in the microarrays, we identified 170 differentially expressed miRNAs (69 upregulated and 101 downregulated miRNAs) in KS versus adjacent healthy tissues. Among the most significantly upregulated miRNAs were miR-126-3p, miR-199a-3p, miR-16-5p, and the 13 KSHV-related miRNAs. The most significantly downregulated miRNAs included miR-125b-1-3p and miR-1183. Eight upregulated miRNAs, miR-181b-5p, miR-199a-3p, miR-15a-5p, miR-126-3p, miR-1297, kshv-miR-k12-12-3p, kshv-miR-k12-1-5p, and miR-16-5p, and two downregulated miRNAs, miR-125b-1-3p and miR-1183, were confirmed by qRT-PCR in 18 paired KS samples. The qRT-PCR results for 10 miRNAs were consistent with our microarray results. The miR-125b-1-3p and miR-16-5p had statistically significant associations with HHV-8 and HIV infections in KS. The results of miRNA profiling showed that KS appears to have unique expression patterns when compared with paired adjacent healthy tissues, suggesting that deregulation of miRNAs plays an important role in the progression of KS. These differentially expressed miRNAs may provide novel diagnostic and prognostic tools.