ABSTRACT
Objective To observe the expression of ChemR23 induced by Angiotensin Ⅱ (Ang Ⅱ) in podocyte and its role in renal injury.Methods Conditionally immortalized mice podocytes were cultured in vitro.Immunofluorescence was used to observe the sub-cellular location of ChemR23.The expressions of ChemR23,Nephrin and Podocin stimulated by different concentrations of Ang Ⅱ were detected by qRT-PCR and Western blotting.Lentivirus targeting ChemR23 was used.The expressions of Nephrin and Podocin and the phosphorylation state of NF-κB P65 were detected by Western Blot.The inhibitor of NF-κB P65 was added to the cultural medium for 2 h before Ang Ⅱ stimulation.The effect of NF-κB P65 inhibitor on Ang Ⅱ-induced expression of Nephrin and Podocin was detected by Western Blot.Results It is showed that ChemR23 was located in cytosol and membrane.Compared with the normal control,the expression of ChemR23 was significantly increased by Ang Ⅱ in mRNA and protein level,while the expressions of Nephrin and Podocin were decreased (P ＜ 0.05).When using Lentivirus vector to interfere the expression of ChemR23,Ang Ⅱ-repressed expressions of Nephrin and Podocin were restored (P ＜ 0.05).Western Blot showed the level of phosphorylated NF-κB P65 was significantly increased by Ang Ⅱ stimulation (P ＜ 0.05),which could be inhibited by interfering the expression of ChemR23.When adding the NF-κB P65 inhibitor,the low expression of Nephrin and Podocin induced by Ang Ⅱ stimulation was restored (P＜0.05).Conclusions Ang Ⅱ can induce ChemR23 expression,which activates NF-κB P65 signaling pathway,and then inhibits the expressions of Nephrin and Podocin.Targeting ChemR23 is a potential way to alleviate podocyte injury caused by Ang Ⅱ.
ABSTRACT
Objective To observe the role and related mechanism of chemerin and its receptor ChemR23 in glomerular endothelial cells (GEnCs) stimulated by high glucose.Methods Mouse GEnCs were cultured and divided into control group,20.0 mmol/L high glucose group,40.0 mmol/L high glucose group and mannitol control group.Then the expressions of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in cell culture supematant as well as the expressions of intracellular protein and mRNA of chemerin,ChemR23,IL-6 and TNF-α were detected.Lentiviral transfection targeting ChemR23 was applied before high glucose-or Chemerin-stimulated,and expressions of supernatant and intracellular mRNA of IL-6 and TNF-α were measured.Meanwhile whether p38 mitogen-activated protein kinase (p38 MAPK) pathway was activated by high glucose was detected.The specific inhibitor of p38 MAPK was added prior to high glucose-stimulated,then supernatant and intracellular mRNA expressions of IL-6 and TNF-α was detected.The supernatant expressions of IL-6 and TNF-α were measured by ELISA.The intracellular protein expression and p38 MAPK phosphorylation activity were detected by Western blotting.The mRNA expression was detected by real time PCR.Results Compared with those in the control group,in high glucose groups the expressions of IL-6,TNF-α and chemerin were significantly increased (all P ＜ 0.05),however,the expressions of ChemR23 did not change (all P ＞ 0.05);the supernatant and mRNA expressions of IL-6 and TNF-α were also elevated in the chemerin group (all P ＜ 0.05).Lentivirus baring shRNA could efficiently suppress ChemR23 expression,and the Chemerin-or high glucose-induced expressions of IL-6 and TNF-α were reduced (all P ＜ 0.05).Also it could significantly reduce the expression of phosphorylated-p38 MAPK (p-p38 MAPK) induced by high glucose (P ＜ 0.05),as high glucose group had higher p-p38 MAPK than control group (P ＜ 0.05).While the high glucose-elevated expressions of IL-6 and TNF-α were significantly attenuated by p38 MAPK inhibitor (all P ＜ 0.05).Conclusions High glucose stimulation can induce the expression of chemerin in GEnCs.By binding to ChemR23,chemerin activates p38 MAPK signaling pathway,and then promotes the expressions of IL-6 and TNF-α.These inflammatory cytokines aggravate inflammation of GEnCs.