Hai-Yan Hu1, Jun-Qiang Wang. 1. Department of Prosthodontics, Yanan Affiliated Hospital of Yanan University. Yanan 716000, Shaanxi Province, China. E-mail:hbo_liu@126.com.
Abstract
PURPOSE: To investigate the effects of miR-142-3p overexpression on secretion of inflammatory factors in human periodontal ligament cells (hPDLCs) induced by lipopolysaccharide (LPS) and its underlying mechanism. METHODS: hPDLCs were cultured by tissue cultivation in vitro and treated with various concentrations of LPS for 6, 12, 24 and 48 h. hPDLCs were treated with miR-142-3p mimics for 24 h in the presence of 2.0 μg/mL LPS and the expression levels of inflammatory factors (TNF-α, IL-6 and IL-1β) were detected by ELISA assay. The target relationship between miR-142-3p and interleukin-1 receptor- associated kinase 1 (IRAK1) was detected by dual-luciferase reporter assay. The miR-142-3p and IRAK1 mRNA expression was measured by qRT-PCR. The protein expression levels of IRAK1, TLR4 and NF-κB were detected by Western blotting. Statistical analysis was performed using SPSS 16.0 software package. RESULTS: The miR-142-3p expression level was decreased significantly at 24 h in 2.0 μg/mL LPS-treated hPDLCs (P<0.01). Transfection of miR-142-3p mimics remarkably increased miR-142-3p expression (P<0.01). The secretion of inflammatory factors (TNF-α, IL-6 and IL-1β) in LPS-treated hPDLCs was significantly decreased by miR-142-3p overexpression (P<0.05). Dual-luciferase reporter assay showed a directly targeting relationship between miR-142-3p and IRAK1. Overexpression of miR-142-3p significantly reduced the IRAK1 protein expression in LPS-treated hPDLCs (P<0.05), whereas no obvious effect on IRAK1 mRNA expression was noted (P>0.05). Moreover, miR-142-3p overexpression markedly diminished the protein expression of TLR4 and phosphorylated NF-κB in LPS-treated hPDLCs (P<0.05). CONCLUSIONS: Overexpression of miR-142-3p can alleviate the inflammatory response induced by LPS in hPDLCs and the underlying mechanism may be associated with targeting and inhibiting IRAK1 expression leading to suppression of TLR4/NF-κB inflammatory signaling pathway through which miR-142-3p overexpression protects peridentium against inflammation.
PURPOSE: To investigate the effects of miR-142-3p overexpression on secretion of inflammatory factors in human periodontal ligament cells (hPDLCs) induced by lipopolysaccharide (LPS) and its underlying mechanism. METHODS: hPDLCs were cultured by tissue cultivation in vitro and treated with various concentrations of LPS for 6, 12, 24 and 48 h. hPDLCs were treated with miR-142-3p mimics for 24 h in the presence of 2.0 μg/mL LPS and the expression levels of inflammatory factors (TNF-α, IL-6 and IL-1β) were detected by ELISA assay. The target relationship between miR-142-3p and interleukin-1 receptor- associated kinase 1 (IRAK1) was detected by dual-luciferase reporter assay. The miR-142-3p and IRAK1 mRNA expression was measured by qRT-PCR. The protein expression levels of IRAK1, TLR4 and NF-κB were detected by Western blotting. Statistical analysis was performed using SPSS 16.0 software package. RESULTS: The miR-142-3p expression level was decreased significantly at 24 h in 2.0 μg/mL LPS-treated hPDLCs (P<0.01). Transfection of miR-142-3p mimics remarkably increased miR-142-3p expression (P<0.01). The secretion of inflammatory factors (TNF-α, IL-6 and IL-1β) in LPS-treated hPDLCs was significantly decreased by miR-142-3p overexpression (P<0.05). Dual-luciferase reporter assay showed a directly targeting relationship between miR-142-3p and IRAK1. Overexpression of miR-142-3p significantly reduced the IRAK1 protein expression in LPS-treated hPDLCs (P<0.05), whereas no obvious effect on IRAK1 mRNA expression was noted (P>0.05). Moreover, miR-142-3p overexpression markedly diminished the protein expression of TLR4 and phosphorylated NF-κB in LPS-treated hPDLCs (P<0.05). CONCLUSIONS: Overexpression of miR-142-3p can alleviate the inflammatory response induced by LPS in hPDLCs and the underlying mechanism may be associated with targeting and inhibiting IRAK1 expression leading to suppression of TLR4/NF-κB inflammatory signaling pathway through which miR-142-3p overexpression protects peridentium against inflammation.