Angptl2 Mediates Actue Inflammation In The Eye By Activating Müller Cell Through PirB

Angiopoietin-like protein 2(Angptl2)belongs to angiopoietin-like proteins(ANGPTLs)and is a secretory glycoprotein expressed in various organs of the body.The expression of Angptl2 is increased under the stimulation of hypoxia,high pressure and inflammation,and It’s also considered as an important inflammatory inducer in various acute and chronic inflammation,and it plays important role in Corneal Inflammation,endophthalmitis,retinitis,uveitis and so on.Studies have found that when inflammation occurs in the eye,the expression of Angptl2 mRNA will be increased,inducing macrophages to migrate into the eye and releasing pro-inflammatory factors such as interleukin-1β(IL-1β),interleukin-6(IL-6),tumor necrosis factor-a(TNF-a).However,the mechanism and pathway of how Angptl2 induce inflammation in eyes are not completely clear.In previous studies,Angptl2 mediates inflammation in the eye mainly by promoting the release of pro-inflammatory cytokines through monocytes/macrophages.Since there is a lack of monocytes/macrophages in the retina,Müller glial cells are considered to be the main source of retinal inflammatory factors.Therefore,we speculate that Angptl2 may activate retinal Müller cells to participate inflammation in the eye.Our research focus on the following three studies: Firstly,we confirm that LPS-Stimulated Induction of Angptl2 mRNA Expression;Secondly,we want to prove that Angptl2 stimulates the proliferation of Müller cells,enhances glial activation and increases the release of pro-inflammatory factors.Finally,we would like to verify that Angptl2 mediates actue inflammation in the eye by activating Müller cell through PirB.Objectives:To study the role and mechanism of angiopoietin-like protein 2(Angptl2)in mediating inflammation in the eye.Methods:1.SD rats were randomly divided into LPS group and PBS group.Rats in LPS group were injected with 0.2 mg LPS in vitreous cavity.The control group was added with equal volume of PBS.RT-PCR was used to detect the expression of retinal Angptl2 in the two groups.2.Müller cells were randomly divided into Angptl2 group and PBS group,Angptl2 group was addedAngptl2 at a final concentration of 1ug/ml,The control group was added with equal volume of PBS,and the cells were incubated for 0h,6 h,18 h and 24 h,cell count the Proliferation of Müller cells.The expression of GFAP in Müller cells was observed by Immunofluorescence staining and the expression of pro-inflammatory factors IL-1β,IL-6 and TNF-α were detected by RT-PCR.3.Immunofluorescence was used to observe the expression of paired immunoglobulin-like receptor B(PirB)on Müller cells.Angptl2 was added toMüller cells and then Müller cells were transfected with Ad-PirB-siRNA and Ad-C.we divided Müller cells into PBS control group,Angptl2 group,Ad-C+Angptl2 group and Ad-PirB-siRNA+Angptl2group.The expression of inflammatory factors was observed by RT-PCR.Results:1.Angptl2 mRNA level was increased notably in the retina of LPS group compared with that of control group.2.Compared with PBS group,treatment with Angptl2 resulted in a higher proliferation rate of Müller cells,levels of IL-1β,IL-6,TNF-α and GFAP.3.PirB was expressed on retinal Müller cells.levels of IL-6 and TNF-α in the Ad-PirB-siRNA+Angptl2 group was significantly lower than those in the Angptl2 group and Ad-C+Angptl2 group.Conclusions:Angptl2 mediates actue inflammation in the eye by activating Müller cell through PirB.