The Mechanism Of CCN1 Promoteing IL-36 Production In Keratinocytes To Participate In The Pathogenesis Of Psoriasis

Psoriasis is a popular chronic inflammatory skin disease,which includs ordinary Psoriasis,erythrodermic Psoriasis and pustular Psoriasis characterized by red,scaly and well-demarcated skin lesions formed by the hyper-proliferation of epidermal keratinocytes?KC?.The pathogenesis includes epidermal keratinocytes hyper-proliferation which is caused by excessive activation of hyperplasia,parakeratosis and inflammatory cell infiltration leading to patchy skin surface area scales fall off as well as local chronic inflammation of the skin.In recent years,numerous studies show that Psoriasis symptoms?such as keratinocyte hyperplasia,neovascularization,inflammation,etc.?can be attributed to a large number of local infiltration of inflammatory cytokines.CCN1,also known as Cysteine-rich protein 61?Cysteine-rich angiogenic inducer61,Cyr61?,is a secreted matrixcelluar protein.CCN1 is now recognized as a new pro-inflammatory cytokine,which is involved in a variety of inflammatory and autoimmune diseases.In 2015,we reported that CCN1 promots excessive keratinocytes activation,proliferation in aggravating psoriasis skin lesions.Recently,we found CCN1 can promote keratinocytes to produce IL-6,IL-8 and IL-1?.CCN1may be involved in psoriasis via a variety of pathways.But there are still a lot of problem yet and need to be solved.What is the expressive phase of CCN1 in psoriasis.What role does it play?Is CCN1 induced in the initiation of the disease or expresss high in the late phase of Psoriasis.Recent studies showed that in patients with psoriatic skin lesions,IL-36?,IL-36?,IL-36?were highly expressed.In addition,significantly reduced psoriasis-like symptoms were observed in imiquimod treated IL-36?^-/-mice.While overexpression of IL-36?in mice spontaneously generates psoriasis-like lesions.It has been reported that IL-36 synergistically assists IL-1?to increase local inflammation in psoriasis.All of these studies illustrate that IL-36 is important in the development of psoriasis.Therefore,it is significant and applicable to find the factors regulating IL-36 to block the disease from the orgin.In this research,we first established the IMQ/IL-23-induced psoriasis-like mouse model,then collected all skin samples at different time points to analyze the expression pattern of inflammatory factors and CCN1.The results showed that CCN1and inflammatory cytokines TNF-?,IL-17,IL-23 quickly increased from the first two days of modeling and reached the peak,which suggests that CCN1,TNF-?,IL-17,and IL-23 may be involved in the initial occurrence of psoriasis.Conversely,IL-36?,IL-36?and IL-36?are significantly induced on the seventh day from the beginning of the modeling,which suggests that IL-36?,IL-36?and IL-36?may be involved in psoriasis maintenance and relapse.Thereby we established our hypothesis:"CCN1may be involved in the pathogenesis of psoriasis via regulating IL-36 expression."Next,we studied the regulation between CCN1 and IL-36 in cultured KC and HaCaT cell line in vitro.The results showed that both CCN1 protein extra-added or PCDH-CCN1 expression plasmid transfection are able to selectively promote IL-36?and IL-36?expression.On the other hand,IL-36?and IL-36?expression were selectively inhibited upon CCN1 interference.In addition,it is well known that TNF-?,IL-17,IL-22 can induce IL-36 expression.So what is the relationship between these already known cytokines and CCN1 in regulating IL-36 production?Our data showed that CCN1,which is not involved in the regulatory effect of TNF-?,IL-17and IL-22 on IL-36 expression,can induces IL-36 expression directly without the involvement of TNF-?and IL-22.So we concluded that CCN1 regulates IL-36 in a parallel regulatory pathway with TNF-?,IL-17,IL-22 regulation.Further,we established IMQ-induced psoriasis-like model and treated the model mice by specific anti-CCN1 monoclonal antibodies to block the expression of CCN1and analyzed the expression of IL-36.We found that CCN1 expression inhibition in vivo can selectively reduce IL-36?and IL-36?expression resulting in a relieved symptom.In addition,using signal pathway inhibitor and predicting promoter binding sites,we further analyzed the molecular mechanisms of CCN1 regulating IL-36.The results showed that,CCN1 selectively upregulated IL-36?and IL-36?expression through the specific combination of KC cell surface integrin receptors?6?1,signaling through PI3K-AKT-NF-?B and ERK-AP1 pathways,then increased p65 and ERK phosphorylation to the nucleus and binding to IL-36?and IL-36?promoter to start the expression.In conclusion,our study found that:CCN1 not only participates in promoting psoriasis KC hyper-proliferation,but also play an important role in expanding inflammation during disease progression,such as regulation of IL-1?,IL-36?and IL-36?to participate in the expansion of local inflammation in psoriasis as an up-stream origin.Therefore,CCN1,from different aspects,became involved in the network of psoriatic KC and inflammatory microenvironment promoting the development of pathological processes of psoriasis.Moreover,our researches provided the experimental and theoretical basis of CCN1 for the clinical treatment of psoriasis as a new target.In summary,we found CCN1 can regulate IL-36 expression via AKT-NF-?B/ERK-MAPK pathways to participate in Psoriasis in vitro and in vivo to expand the inflammatory microenvironment which plays an important role in the pathogenesis of psoriasis.Also,blocking CCN1 function significantly inhibit skin damage and inflammation,suggesting that CCN1 may be a potential target for clinical treatment of psoriasis and psoriasis research,and provided strong new evidence in the mechanism of clinical treatment.