An Exploration of the Role of MicroRNAs in Psoriasis: A Systematic Review of the Literature

Abstract

Psoriasis is recently characterized by a specific microRNAs (miRNAs) expression profile, which guides the researchers' efforts to explore the therapeutic targets and objective biomarkers that reflect the diagnosis and disease activity in clinical use for psoriasis.The paper presents a state-of-the-art review of expression and function of miRNAs in psoriasis along with its clinical implications.We analyzed all literature searched by keywords "microRNA" and "psoriasis" in PubMed (Medline) from inception up to July 2015, and the references in the literature searched were also considered.Relevant literature was chosen according to the objective of this review. Relevant literature was searched by 3 independent investigators, and experts in the field of miRNAs and psoriasis were involved in analyzing process.We included any study in which role of miRNAs in psoriasis was examined in relation to disease pathogenesis, diagnosis, and treatment.The specific miRNAs profile has been identified from human psoriatic skin, blood, and hair samples. It is found that genetic polymorphisms related to some of specific miRNAs, miR-146a for example, are associated with psoriasis susceptibility. Key roles of several unique miRNAs, such as miR-203 and miR-125b, in inflammatory responses and immune dysfunction, as well as hyperproliferative disorders of psoriatic lesions have been revealed. Moreover, circulating miRNAs detected from blood samples have a potential of clinic application to be the biomarkers of diagnosis, prognosis, and treatment responses. Additionally, a new layer of regulatory mechanisms mediated by miRNAs is to some extent revealed in pathogenesis of psoriasis.The dramatically altered mRNA expression profiles are displayed in psoriasis, and some of these may become disease markers and therapeutic targets. Herein, this work underscores the potential importance of miRNAs to diagnosis, prognosis, and treatment of psoriasis. However, further study in this field is worth doing in the future, as the exact roles of miRNAs in psoriasis have not been fully elucidated.Systematic review registration number is not registered.

FIGURE 1

Possible signaling mechanisms underlying miRNAs action with the examples of miR31 and miR-21. A, a signal transduction feedback loop, in which miR-31 and NF-κB play a key role, has been delineated. This feedback loop contributes to inflammatory responses and skin phenotype of psoriasis. B, a complex network formed by miR-21 activity and STAT3 activation contributes to keratinocytes proliferation in psoriasis. The detailed information of these signals is seen in the related body text. AP-1 =  Jun/activating protein 1; CXCLs = chemokine (C-X-C motif) ligands; FIH-1 = factor-inhibiting hypoxia-inducible factor 1; IL = interleukin; NF-κB = nuclear factor κB; ppp6c = protein phosphatase 6c; P2X7R = receptor of purinergic recepter p2x, ligand-gated ion channel,7; STAT3 = signal transducer and activator of transcription 3; TGF-β1 =  transforming growth factor β1; Th17 = T helper type-17; VEGF = vascular endothelial growth factor.