LncRNA GAS6-AS2 Participates In The Pathogenesis Of Psoriasis Via Regulating Inflammatory Response And Proliferation Of Keratinocytes

Background:Psoriasis is an immune-mediated chronic inflammatory skin disease,characterized by infiltration of lymphocytes and excessive proliferation of keratinocytes.Keratinocytes are the main effector cells in the pathogenesis of psoriasis,but the mechanism that leads to the abnormal differentiation,hyperproliferation and excessive inflammatory response of keratinocytes is not completely elucidated.It’s reported that lncRNAs take part in cutaneous biology,including regulation of keratinocytes differentiation,modulating melanocyte function,affection on hair growth and cell proliferation,and involve in hyperproliferation skin diseases.GAS6-AS2 is a newly reported lncRNA that promote proliferation of tumor cells and is involved in the pathogenesis and progression of melanoma and bladder cancer.By bioinformatic analysis of RNA-seq in psoriatic lesions,lncRNA GAS6AS2 was found one of the most differentially expressed lncRNAs in psoriasis,but its role in keratinocytes has not been studied yet.Motivation:This study is to figure out the function and molecular mechanism of GAS6-AS2 that dedicate to the development of psoriasis,and present new clues for searching novel therapeutic target.Method:The RNA-seq data in psoriatic lesions was downloaded from NCBI and the expression of lncRNA GAS6-AS2 was analyzed by bioinformatics.The level of GAS6-AS2 in psoriatic lesions and psoriatic peripheral blood mononuclear cells(PBMCs)was detected by RT-qPCR,including the expression of GAS6-AS2 in PBMCs in patients with psoriasis receiving anti-IL-17A biologic therapy.We activated HaCaT cells with psoriasis-related pro-inflammatory cytokines such as IL-17A or IL22 and then detected GAS6-AS2 expression by RT-qPCR.The expression of cytokines and chemokines that secreted from HaCaT cells transfected with GAS6AS2-specific shRNA were detected by RT-qPCR and ELISA.EdU proliferation assay and flow cytometric analysis of cell cycle was performed on GAS6-AS2 knockdown HaCaT cells.The biological function of GAS6-AS2 was analyzed by RNA-seq,and GAS6-AS2-TF-mRNA regulatory network was constructed to predict the transcriptional factors and the downstream pathway that interact with GAS6-AS2.Results:LncRNA GAS6-AS2 was found downregulated in the psoriasis skin lesions and PBMCs by bioinformatic analysis and experimental validation,but the expression of GAS6-AS2 in psoriatic PBMCs was significantly restored after anti-IL-17A biological therapy.IL-17A and IL-22 can induce the low expression of GAS6-AS2 in keratinocytes.Knock down GAS6-AS2 in keratinocytes decreased the secretion of pro-inflammatory cytokines and chemokines such as TNF-alpha,IL-6,CCL20,CXCL1.Downregulated GAS6-AS2 of keratinocytes can suppress cell proliferation and induce cell cycle arrest at G0/G1 phase.Four potential transcription factorbinding motifs,including NFκB2,CEBPB,XBP1,and ETS1,were identified in the promoter regions of GAS6-AS2 using the PROMO program.lncRNA GAS6-AS2 plays a role through regulating NF-kappa B pathway validated by GAS6-AS2-TFmRNA regulatory network and western blot.Conclusion:lncRNA GAS6-AS2 take part in the pathogenesis of psoriasis by regulating the secretion of pro-inflammatory cytokines and chemokines and the proliferation of keratinocytes via mediating NF-kB signaling pathway.