Abnormal Levels of Expression of Plasma MicroRNA-33 in Patients With Psoriasis

A panel of blood-based circulatory miRNAs with diagnostic potential in patients with psoriasis

Psoriasis is a chronic inflammatory skin disease with keratinocyte hyperproliferation and T cells as key mediators of lesional and systemic inflammatory changes. To date, no suitable differential biomarkers are available for the disease diagnosis. More recently, microRNAs have been identified as critical regulators of lesional and systemic immune changes in psoriasis with diagnostic potential. We have performed expression profiling of T cell-specific miRNAs in 38 plasma samples from psoriasis vulgaris patients and an equal number of age- and gender-matched healthy subjects. Our findings have identified a panel of five blood-based circulatory miRNAs with a significant change in their expression levels, comprising miR-215, miR-148a, miR-125b-5p, miR-223, and miR-142-3p, which can differentiate psoriasis vulgaris patients from healthy individuals. The receiver operating characteristic (ROC) curves for all five miRNAs individually and in combination exhibited a significant disease discriminatory area under the curve with an AUC of 0.762 and a p < 0.0001 for all the miRNAs together. Statistically, all five miRNAs in combination depicted the best-fit model in relation to disease severity (PASI) compared with individual miRNAs, with the highest R2 value of 0.94 and the lowest AIC score of 131.8. Each of the miRNAs also exhibited a significant association with at least one of the other miRNAs in the panel. Importantly, the five miRNAs in the panel regulate one or more immune-inflammation pathways based on target prediction, pathway network analysis, and validated roles in the literature. The miRNA panel provides a rationalized combination of biomarkers that can be tested further on an expanded cohort of patients for their diagnostic value.

Contribution of the Environment, Epigenetic Mechanisms and Non-Coding RNAs in Psoriasis

Despite the increasing research and clinical interest in the predisposition of psoriasis, a chronic inflammatory skin disease, the multitude of genetic and environmental factors involved in its pathogenesis remain unclear. This complexity is further exacerbated by the several cell types that are implicated in Psoriasis’s progression, including keratinocytes, melanocytes and various immune cell types. The observed interactions between the genetic substrate and the environment lead to epigenetic alterations that directly or indirectly affect gene expression. Changes in DNA methylation and histone modifications that alter DNA-binding site accessibility, as well as non-coding RNAs implicated in the post-transcriptional regulation, are mechanisms of gene transcriptional activity modification and therefore affect the pathways involved in the pathogenesis of Psoriasis. In this review, we summarize the research conducted on the environmental factors contributing to the disease onset, epigenetic modifications and non-coding RNAs exhibiting deregulation in Psoriasis, and we further categorize them based on the under-study cell types. We also assess the recent literature considering therapeutic applications targeting molecules that compromise the epigenome, as a way to suppress the inflammatory cutaneous cascade.

Relationship between mir-126 expression in children with psoriasis, disease progression and therapeutic response

This study aimed to investigate the expression level of miR-126 in children with psoriasis in the epidermis affected by psoriasis and intact buccal epithelium, establish the impact on the characteristics of the course of psoriasis and the results of therapy in children with psoriasis of initial expression levels of miR-126. miR-126 expression levels in psoriatic keratinocytes and buccal epithelium were determined in 54 children with psoriasis on the severity of psoriasis, treatment efficacy. miR-126 levels in the buccal epithelium in children with psoriasis were reduced compared to healthy children (AUC=0.776±0.048, p<0.001). There were no discrepancies between miR-126 expression levels in psoriatic keratinocytes and buccal epithelium (p=0.097). There are statistically significant discrepancies between miR-126 expression levels in the psoriatic epidermis depending on the clinical form of psoriasis (AUC=0.637±0.056; p=0.014) and severity according to BSA (AUC=0.634±0.063; p=0.034). Depending on the miR-126 level in the buccal epithelium, the response to treatment (PASI<75) in children with high miR-126 is worse than in children with expected miR-126 levels (OR 2.79; 95%; CI: 1.19 - 6.51). Treatment failures were observed in children with high levels of miR-126 in the buccal epithelium compared to miR-126 in the psoriatic epidermis: children aged 12/13 to 17 years (OR 2.44; 95% CI: 1.02 - 5.85), children with PGA=4 (OR 3.16; 95% CI: 1.34 - 7.43). The location and level of miR-126 expression affects the course of psoriasis and the outcome of treatment. High levels of miR-126 in psoriatic keratinocytes lead to manifestations of plaque psoriasis with a course of moderate to severe forms. Initial miR-126 levels in the buccal epithelium in children with psoriasis are a prognostic criterion for response to therapy and can be used as a marker for prescribing systemic treatment.

Decreased microRNA-126 expression in psoriatic CD4+ T cells promotes T-helper 17 cell differentiation and the formation of dermatitis in imiquimod-induced psoriasis-like mice

Psoriasis is a chronic inflammatory skin disease with multiple genetic backgrounds, whose etiology and pathogenesis are still unclear. Complex T-cell immune imbalance has been demonstrated to play an important role in pathogenesis of psoriasis. This study reported that microRNA-126 (miR-126) expression was decreased in CD4⁺ T cells of both psoriasis patients and psoriasis-like mouse models and its expression was negatively correlated with the Psoriasis Area and Severity Index (PASI) score of psoriasis patients. Conditional Mir126 knockout in mouse CD4⁺ T cells can obviously aggravate the psoriasis-like dermatitis and promote T-helper (Th)1 and Th17 cells' infiltration in spleen of imiquimod (IMQ)-induced psoriasis-like mouse model. In addition, the mRNA expression of Il17a and Il17f were significantly increased in mouse naïve CD4⁺ T cells with Mir126 knockout after stimulating with CD3 and CD28. Compared with naïve CD4⁺ T cells, the expression of Mir126 was decreased in Th17 cells, and Mir126 knockout notably promoted the differentiation of naïve CD4⁺ T cells to Th17 cells as well as the mRNA expression of Il17a, Il17f, Rorc, and Il23R. Our results revealed that decreased miR-126 in psoriatic CD4⁺ T cells might accelerate the formation of skin lesions through promoting the differentiation of Th17 cells, thus suggesting a potential intervention target for psoriasis.

Circulating microRNAs: Biomarkers of disease

MicroRNAs are a class of endogenous noncoding single-stranded RNA molecules with approximately 20-24 nucleotides and are associated with a broad range of biological processes. Researchers found that microRNAs are abundant in tissues, and more importantly, there are also trace circulating microRNAs that exist in biological fluids. In recent years, circulating microRNAs had emerged as promising diagnostic and prognostic biomarkers for the noninvasive detection of diseases with high specificity and sensitivity. More importantly, specific microRNA expression signatures reflect not only the existence of early-stage diseases but also the dynamic development of advanced-stage diseases, disease prognosis prediction, and drug resistance. To date, an increasing number of potential miRNA biomarkers have been reported, but their practical application prospects are still unclear. Therefore, microRNAs, as potential diagnostic and prognostic biomarkers in a variety of diseases, need to be updated, as they are of great importance in the diagnosis, prognosis and prediction of therapeutic responses. In this review, we summary our current understanding of microRNAs as potential biomarkers in the major diseases (e.g., cancers and cardio-cerebrovascular diseases), which provide the basis for the design of diagnosis and treatment plan and the improvement of the cure rate.

Psoriasis Pathogenesis and Treatment

Research on psoriasis pathogenesis has largely increased knowledge on skin biology in general. In the past 15 years, breakthroughs in the understanding of the pathogenesis of psoriasis have been translated into targeted and highly effective therapies providing fundamental insights into the pathogenesis of chronic inflammatory diseases with a dominant IL-23/Th17 axis. This review discusses the mechanisms involved in the initiation and development of the disease, as well as the therapeutic options that have arisen from the dissection of the inflammatory psoriatic pathways. Our discussion begins by addressing the inflammatory pathways and key cell types initiating and perpetuating psoriatic inflammation. Next, we describe the role of genetics, associated epigenetic mechanisms, and the interaction of the skin flora in the pathophysiology of psoriasis. Finally, we include a comprehensive review of well-established widely available therapies and novel targeted drugs.