| BackgroundPsoriasis is a chronic immune-mediated disease that primarily affects the skin and joints.Environmental factors(alcohol,infections,certain medications,obesity,stress,nicotinism,etc.)play a significant role in the pathogenesis of psoriasis.Epigenetic mechanisms in psoriasis include DNA methylation,histone modifications and non-coding RNAs regulation.Epigenetic factors can regulate gene expression at the transcriptional and posttranscriptional levels by micro RNAs and long non-coding RNAs.Mi RNA is a kind of small non coding DNA with a length of about 20-22 nucleotides,which can regulate more than 60% of protein coding genes and participate in post transcriptional gene regulation through the translation inhibition and degradation of mRNA.Mi RNA generally plays a negative regulatory role by combining with specific target mRNA to promote the degradation of target mRNA and inhibit translation,and it also participates in a series of biological processes such as cell differentiation,proliferation and apoptosis.Mi RNA is generally involved in the occurrence and development of various diseases,such as malignant tumor、psoriasis、itiligo、alopecia areata、atopic dermatitis and other immune-related diseases.Previous studies have found that miRNAs can regulate cell proliferation,keratinocyte differentiation,apoptosis and atypical immune activation in psoriasis.For example,miR-187 can inhibit the proliferation of keratinocytes by targeting B7 homolog 3 protein(B7-H3,also known as CD276).miR-183-3p can inhibit the proliferation and migration of keratinocytes in psoriasis by inhibiting growth factor receptor binding 2-associated binding protein 1(GAB1).In addition,in the mouse model of psoriasis,overexpression of miR-187 can reduce acanthosis and reduce the severity of the disease.Mi R-320 b negatively regulates keratinocyte proliferation in psoriasis by targeting AKT serine/threonine kinase 3(AKT3)to regulate signal transducer and activator of transcription-3(STAT3)and stress-activated protein kinase/c-Jun N-terminal Kinase(SAPK/JNK)signaling pathways.These studies show that miRNA plays an important role in the pathogenesis of psoriasis.At present,the research of miRNA in psoriasis leads the forefront.Therefore,to identify key miRNAs in psoriasis would help clarify the molecular mechanism of psoriasis.ObjectiveIn this study,Weighted correlation networkanalysis(WGCNA)was used to integrate high-throughput transcriptome data taken from skin tissue samples in psoriasis and the normal controls in order to obtain the interaction network among psoriasis-related genes,functional clusters,signal pathways and protein members corresponding to their differentially expressed genes,which is to be verified by RT PCR in order to determine the key molecular markers and signal pathways of psoriasis,providing new ideas for diagnosis and clinical treatment of psoriasis.Methods1、Micro ribonucleic acid(miRNA)and messenger ribonucleic acid(mRNA)data were obtained from Gene Expression Omnibus(GEO).2、The R language limma R package was used to screen differentially expressed mRNAs(differential expressed mRNAs,DEmRNAs)and differentially expressed miRNAs(differential expressed miRNAs,DEmiRNAs).3、David database was used for functional enrichment analysis of demrnas.The weighted correlation network analysis(WGCNA)R package was used to analyze the coexpression network of all miRNAs.4、 Based on the identified hub miRNA,the miRNA-mRNA regulatory network was constructed and the clinical samples were verified by real-time polymerase chain reaction(RT-PCR).Results1、A total of 639 DEmRNAs and 84 DEmiRNAs were identified by GEO.Functional enrichment found that DEmRNAs were significantly enriched in immune-related biological functions,toll-like receptor signaling pathway,cytokine-cytokine receptor interaction and chemokine signaling pathway being the examples.In WGCNA,we found that turquoise module was the hub module.2、A total of 10 hub miRNA were identified from the intersection of 84 DEmiRNA predicted by microarray data set and 21 DEmiRNA obtained by weighted gene co-expression network analysis.They are up-regulated hsa-miR-21-3p、hsa-miR-21-5p、hsa-miR-31-5p、hsa-miR-18a-5p、hsa-miR-33b-3p,and down-regulated hsa-miR-181a-2-3p、hsa-miR-181a-5p、hsa-miR-6510-3p、hsa-miR-30a-3p、hsa-miR-30c-2-3p,only 8 of which have matching target genes.Among them,there were 4 up-regulated real hub genes,and 11 of their target genes matched with differentially down-regulated mRNA.Additionally,there were 4down-regulated real hub genes,and 72 of their target genes matched with differentially up-regulated mRNA.3、A total of 97 pairs of negatively regulated miRNA-mRNAs were involved in the miRNA-mRNA regulatory network,for example,hsa-miR-21-3p/hsa-miR-18a-5p-F3、hsamiR-21-5p-CLDN8、hsa-miR-33b-3p-PLCB4、hsa-miR-30a-3p-IL-1B、hsa-miR-181a-5pCCL8、hsa-miR-181a-5p/hsa-miR-30c-2-3p-CXCL9 and hsa-miR-30c-2-3p-KYNU.4、RT-PCR resilts showed that in psoriasis IL-1B and CXCL9 were up-regulated while CLDN8 was down-regulated,which showed statistically significant differences(P<0.05).The verification results were consistent with the analysis results.ConclusionsThis study has identified multiple differentially expressed genes associated with psoriasis,including down-regulated hsa-miR-181a-5p and CLDN8,and up-regulated IL-1B,CXCL9 and CCL8,with statistically significant differences between IL-1B,CXCL9 and CLDN8(P<0.05).They would bring great potentials in diagnosing and treating psoriasis.What’s more,the successful identification of key molecular markers and signaling pathways would indicate important research directions for better understanding the molecular mechanism of psoriasis.It not only provides new insights for the determination of potential therapeutic targets in the treatment of psoriasis,but also opens up new ideas for the prevention and treatment of psoriasis in the future. |
