Effect And Mechanism On Down-regulated NF-κB And IL-6in Human Keratinocytes By Quercetin

BackgroundThe epigenetic phytochemical agent for regulatory neoplastic and autoimmune diseases is the hot spot in research. In present, lots research are related about neoplatic, only a few about psoriatic autoimmune diseases. The aberrant character of psoriasis is immunogenetic inflammation and proliferation in the keratinocytes. IP-10protein with lOkDa generated from interferon-y is one kind of pro-inflammatory factors/chemokines, which can not only attract the inflammatory cells to the pathogenic focus, but also facilitate the keratinocytes proliferative. Since the IP-10in keratinocytes of the psoriatic lesions is more closely related with the psoriatic state than multiple cytokines in the patients’ plasma, we designed to establish the IP-10induced-kerakinocytes as psoriatic keratinocytes, or as the psoriasis-thrapeutic target cells. The polyphenol quercetin can inhibit tumor cells growth and induce cells differentiation toward apoptosis, moreover, the anti-nflammatory effect can be induced by the quercetin mediated via suppressing IL-6(inflammatory cytokine) production. The nuclear factor NF-κB can be activated by stress, inflammation etc, NF-κB facilitate cells proliferation through up-regulating Cyclin D1and cell cycle progression to promote the cells proliferated. The quercetin is hardly dissoluble in water, which was prepared by us into nanoliposomal quercetin and absorbed by cells easier. In our previous MTT experiment it was demonstrated that20ng/ml IP-10 could facilitate the normal keratinocytes to proliferation, which could be inhibited by40μmol/l Q or10"7mol/l D to appear as antagonist effect. Thus, we design to explore whether could alter the expression of NF-κBp65, Cyclin D1, IL-6or P16associated with proliferation and inflammation and the altered tumor suppressor gene of DNMT1/HDAC1level associated with epigenetic modification induced by Q in comparison with D, to provide novel therapeutic strategy for psoriatic disease.ObjectiveTo study the epigenetic effects on down-regulated NF-κB and IL-6in human keratinocytes by quercetin (Q), and compared the effects with dexamethone (D).Materials and Methods1. The cultured keratinocytes were divided into3groups:①IP-10+Q group:20ng/mlIP-10+40μmol/lQ②IP-10+D group:20ng/mlIP-10+10-7mol/lD and③control group (C):20ng/mlIP-10. The keratinocytess in three groups were cultured for48h.2. The specific methylation (MS) of p16INK4α PCR (MSP), immunoblotiting of DNMT1, HDAC1, NF-κBp65, Cyclin D1, IL-6and p16INK4α and immunostaining of HDAC1or IL-6were performed in each group.3. Statistics process:All the statistical analyses were performed by the SPSS17.0software package and all the data are expressed with x±s. The comparisons of the least three experiments between every two groups were analyze by variance analysis. The inspection level is a=0.05.Results1.When compared with the control group in MS-PCR of p16INK4αmethylation, the methylated p16INK4αin MS-PCR was attenuated in group①and group②, much weaker than that in the group②, P<0.05.2. When compared with the control group, The immunoblotting of DNMT1, HDACl,NF-κBp65,Cyclin D1or IL-6was attenuated in group①, much weaker than that in group②,D,P<0.05, while the p16INK4α expression was promoted in group①, much marked than that in group②,P<0.05.3. When compared with the control group, the expression of HDAC1or IL-6in°immunostaining was down-regulated in group①and group②P<0.05, much weaker than that in group②P<0.05.ConclusionsThe inhibitory effect of proliferation (NF-κB) and inflammation (IL-6) by nanoliposomal quercetin and dexamethone may be mediated through epigenetic-NF-KB signaling. Moreover, the inhibitory effect of nanoliposomal quercetin is more distinct than that of dethamethone.