Identification of an exosomal miRNA-mRNA regulatory network contributing to methotrexate efficacy

OBJECTIVE

Methotrexate (MTX) is an economic and effective medicine treatment for psoriasis. Extracellular vesicle (EV) miRNA biomarkers related to its efficiency have been identified in various diseases. Whether certain miRNA profiles are associated with psoriasis treatment is unknown. In order to determine specific miRNA biomarkers for MTX effectiveness prediction and the severity of psoriasis, our study looked at the variations in circulating EV miRNA profiles before and after MTX therapy.

METHODS

Plasma EV isolation and next-generation sequencing were performed to identify differentially expressed EV miRNAs between GRs (n = 14) and NRs (n = 6). Univariate and multiple linear regression analyses were performed to evaluate the correlation between PASI scores and miRNA expression levels.

RESULTS

15 miRNAs out of a total profile of 443 miRNAs were substantially different between GRs and NRs at baseline, 4 of them (miR-199a-5p, miR-195-5p, miR-196a-5p, and miR-1246) have the potential to distinguish between GRs and NRs [area under the curve (AUC) ≥ 0.70, all P < 0.05]. KEGG pathway analyses revealed differentially expressed miRNAs to potentially target immune-related pathways. SIRT1 was discovered to be a target of miR-199a-5p and involved in MAPK signaling pathway. MiR-191-5p and miR-21-5p expression levels have been discovered to positively correlate with PASI scores[P < 0.05].

CONCLUSION

This pilot investigation found that miR-199a-5p, miR-195-5p, miR-196a-5p, and miR-1246 might be prospective biomarkers to predict the efficacy of MTX, and that miR-191-5p and miR-21-5p were correlated with psoriasis severity. Five of them previously reported to be involved in MAPK signaling pathway, indicating a potential role of MTX in delaying the progression of psoriatic inflammation.

RNA-Based Antipsoriatic Gene Therapy: An Updated Review Focusing on Evidence from Animal Models

Psoriasis presents as a complex genetic skin disorder, characterized by the interaction between infiltrated immune cells and keratinocytes. Substantial progress has been made in understanding the molecular mechanisms of both coding and non-coding genes, which has positively impacted clinical treatment approaches. Despite extensive research into the genetic aspects of psoriasis pathogenesis, fully grasping its epigenetic component remains a challenging endeavor. In response to the pressing demand for innovative treatments to alleviate inflammatory skin disorders, various novel strategies are under consideration. These include gene therapy employing antisense nucleotides, silencing RNA complexes, stem cell therapy, and antibody-based therapy. There is a pressing requirement for a psoriasis-like animal model that replicates human psoriasis to facilitate early preclinical evaluations of these novel treatments. The authors conduct a comprehensive review of various gene therapy in different psoriasis-like animal models utilized in psoriasis research. The animals included in the list underwent skin treatments such as imiquimod application, as well as genetic and biologic injections, and the results of these interventions are detailed. Animal models play a crucial role in translating drug discoveries from the laboratory to clinical practice, and these models aid in improving the reproducibility and clinical applicability of preclinical data. Numerous animal models with characteristics similar to those of human psoriasis have proven to be useful in understanding the development of psoriasis. In this review, the article focuses on RNA-based gene therapy exploration in different types of psoriasis-like animal models to improve the treatment of psoriasis.

The Role of Epigenetic Factors in the Pathogenesis of Psoriasis

Psoriasis is a chronic inflammatory skin disease, the prevalence of which is increasing. Genetic, genomic, and epigenetic changes play a significant role in the pathogenesis of psoriasis. This review summarizes the impact of epigenetics on the development of psoriasis and highlights challenges for the future. The development of epigenetics provides a basis for the search for genetic markers associated with the major histocompatibility complex. Genome-wide association studies have made it possible to link psoriasis to genes and therefore to epigenetics. The acquired knowledge may in the future serve as a solid foundation for developing newer, increasingly effective methods of treating psoriasis. In this narrative review, we discuss the role of epigenetic factors in the pathogenesis of psoriasis.

MiRNA-21-5p induces chicken hepatic lipogenesis by targeting NFIB and KLF3 to suppress the PI3K/AKT signaling pathway

The liver plays a critical role in metabolic activity and is the body's first immune barrier, and maintaining liver health is particularly important for poultry production. MicroRNAs (miRNAs) are involved in a wide range of biological activities due to their capacity as posttranscriptional regulatory elements. A growing body of research indicates that miR-21-5p plays a vital role as a modulator of liver metabolism in various species. However, the effect of miR-21-5p on the chicken liver is unclear. In the current study, we discovered that the fatty liver had high levels of miR-21-5p. Then the qPCR, Western blot, flow cytometry, enzyme-linked immunosorbent assay, dual-luciferase, and immunofluorescence assays were, respectively, used to determine the impact of miR-21-5p in the chicken liver, and it turned out that miR-21-5p enhanced lipogenesis, oxidative stress, and inflammatory responses, which ultimately induced hepatocyte apoptosis. Mechanically, we verified that miR-21-5p can directly target nuclear factor I B (NFIB) and kruppel-like factor 3 (KLF3). Furthermore, our experiments revealed that the suppression of NFIB promoted apoptosis and inflammation, and the KLF3 inhibitor accelerated lipogenesis and enhanced oxidative stress. Furthermore, the cotransfection results suggest that the PI3K/AKT pathway is also involved in the process of miRNA-21-5p-mediate liver metabolism regulation. In summary, our study demonstrated that miRNA-21-5p plays a role in hepatocyte lipogenesis, oxidative stress, inflammation, and apoptosis, via targeting NFIB and KLF3 to suppress the PI3K/AKT signal pathway in chicken.

Non-Coding RNAs as Potential Targets for Diagnosis and Treatment of Oral Lichen Planus: A Narrative Review

Oral lichen planus (OLP) is a chronic inflammatory disease that is characterized by the infiltration of T cells into the oral mucosa, causing the apoptosis of basal keratinocytes. OLP is a multifactorial disease of unknown etiology and is not solely caused by the malfunction of a single key gene but rather by various intracellular and extracellular factors. Non-coding RNAs play a critical role in immunological homeostasis and inflammatory response and are found in all cell types and bodily fluids, and their expression is closely regulated to preserve normal physiologies. The dysregulation of non-coding RNAs may be highly implicated in the onset and progression of diverse inflammatory disorders, including OLP. This narrative review summarizes the role of non-coding RNAs in molecular and cellular changes in the oral epithelium during OLP pathogenesis.

Identification of circulating microRNA patterns in patients in psoriasis and psoriatic arthritis

OBJECTIVE

miRNAs are small non-coding RNAs that control gene expression. Specific intra- and extracellular miRNA signatures have been identified in various diseases. Whether certain miRNA signatures are associated with psoriasis (PsO) and PsA is currently unknown. We aimed to search for circulating miRNA signatures associated with PsO and PsA patients.

METHODS

Expression of miRNAs was analysed by reverse transcription quantitative real-time PCR (RT-qPCR) in the serum of PsA, PsO patients and healthy controls. Demographic and disease-specific characteristics and imaging data from hand MRI were recorded. In the discovery phase, 192 miRNA assays were analysed in 48 samples (PsA, PsO, controls: each N = 16). For validation, 17 selected miRNAs were measured in the total population.

RESULTS

A total of 141 patients and controls were analysed (51 PsA, 40 PsO, 50 controls). In the discovery phase 51 miRNAs in PsO and 64 miRNAs in PsA were down- or upregulated compared with controls, with 33 miRNAs being changed in both (adj. P < 0.05). The 17 top candidates from discovery were assessed in the validation phase, 9 of them discriminated PsA and PsO from controls [area under the curve (AUC) ≥0.70, all P < 0.05]. Four miRNAs (miR-19b-3p, miR-21-5p, miR-92a-3p and let-7b-5p) were significantly differently regulated between PsO and PsA. A combination of these miRNAs increased the AUC to 0.92 in multivariate regression model to discriminate PsO and PsA.

CONCLUSION

miRNA signatures in PsA and PsO patients differ from controls. Nine miRNAs were differentially regulated in PsA and PsO patients, five of them previously reported to be involved in bone and cartilage metabolism, indicating an intimate association of psoriatic inflammation and bone/cartilage changes.

The role of microRNA in psoriasis: A review

Psoriasis is a chronic immune-mediated inflammatory skin disease that involves a complex interplay between infiltrated immune cells and keratinocytes. Great progress has been made in the research on the molecular mechanism of coding and non-coding genes, which has helped in clinical treatment. However, our understanding of this complex disease is far from clear. MicroRNAs (miRNAs) are small non-coding RNA molecules that are involved in post-transcriptional regulation, characterised by their role in mediating gene silencing. Recent studies on miRNAs have revealed their important role in the pathogenesis of psoriasis. We reviewed the current advances in the study of miRNAs in psoriasis; the existing research has found that dysregulated miRNAs in psoriasis notably affect keratinocyte proliferation and/or differentiation processes, as well as inflammation progress. In addition, miRNAs also influence the function of immune cells in psoriasis, including CD4+ T cells, dendritic cells, Langerhans cells and so on. In addition, we discuss possible miRNA-based therapy for psoriasis, such as the topical delivery of exogenous miRNAs, miRNA antagonists and miRNA mimics. Our review highlights the potential role of miRNAs in the pathogenesis of psoriasis, and we expect more research progress with miRNAs in the future, which will help us understand this complex skin disease more accurately.

miRNA-559 and MTDH as possible diagnostic markers of psoriasis: Role of PTEN/AKT/FOXO pathway in disease pathogenesis

Psoriasis is a persistent, inflammatory, autoimmune skin disorder which can be elicited by genetic and environmental factors. Several microRNAs (miRNAs) that are abnormally expressed in psoriasis have emerged as an interesting candidate in psoriasis pathogenesis. However, the expression profile and function of miRNA-559, and its direct target metadherin (MTDH), in psoriasis need to be further illuminated. This study intended to assess miRNA-559 and MTDH levels in skin and sera of psoriatic patients and to investigate their clinical significance in an attempt for developing novel distinct tools for early diagnosis of psoriasis. Moreover, this study aimed at exploring participation of miRNA-559 in regulating MTDH/PTEN/AKT pathway in psoriasis. Expression levels of miRNA-559, AKT, FOXO1 and PTEN were measured by real-time qRT-PCR, whereas MTDH and p27 levels were assessed by ELISA in lesional, non-lesional tissues and serum of 20 psoriatic patients and 20 matching controls. Correlation study was conducted between different parameters. The diagnostic performance of miRNA-559 and MTDH in psoriasis was estimated by receiver operating characteristic (ROC) curve analysis. Expression of miRNA-559 in psoriatic patients was significantly downregulated in both lesional tissues and serum as compared to controls. Conversely, MTDH protein level showed significant increase in both tissues and serum of psoriatic patients and was inversely correlated with miRNA-559 level. Meanwhile, levels of PTEN, AKT and FOXO1 were dramatically changed in psoriatic patients compared to controls. Furthermore, serum miRNA-559 and MTDH displayed comparable diagnostic accuracy in discriminating psoriatic patients from controls. Yet, miRNA-559 demonstrated superior diagnostic performance than MTDH in psoriasis diagnosis. Together, the current findings provide the first suggestion of a new mechanism by which downregulation of miRNA-559 might induce proliferation in psoriasis through modulating PTEN/AKT/FOXO1 pathway by positive regulation of MTDH. Thus, miRNA-559 and MTDH might be proposed as promising diagnostic biomarkers of psoriasis.

The Essential Role of microRNAs in Inflammatory and Autoimmune Skin Diseases-A Review

The etiopathogenesis of autoimmune skin diseases is complex and still not fully understood. The role of epigenetic factors is emphasized in the development of such diseases. MicroRNAs (miRNAs), a group of non-coding RNAs (ncRNAs-non-coding RNAs), are one of the important post-transcriptional epigenetic factors. miRNAs have a significant role in the regulation of the immune response by participating in the process of the differentiation and activation of B and T lymphocytes, macrophages, and dendritic cells. Recent advances in research on epigenetic factors have provided new insights into the pathogenesis and potential diagnostic and therapeutic targets of many pathologies. Numerous studies revealed a change in the expression of some microRNAs in inflammatory skin disorders, and the regulation of miRNA expression is a promising therapeutic goal. This review presents the state of the art regarding changes in the expression and role of miRNAs in inflammatory and autoimmune skin diseases, including psoriasis, atopic dermatitis, vitiligo, lichen planus, hidradenitis suppurativa, and autoimmune blistering diseases.

miRNA implication in the pathogenesis and the outcome of Tunisian endemic pemphigus foliaceous

Pemphigus foliaceous (PF) is a bullous autoimmune skin disease diagnosed through sera and skin analyses. PF severity is associated with maintained anti-Dsg1 sera levels and its prognosis is unpredictable. MicroRNA (miRNA), dynamic regulators of immune function, have been identified as potential biomarkers for some autoimmune diseases. This study aimed to assess the miRNA expression of miR-17-5p, miR-21-5p, miR-146a-5p, miR-155-5p and miR-338-3p using quantitative real-time PCR in peripheral blood mononuclear cells (PBMC) and lesional skin samples from untreated and treated PF patients (both remittent and chronic) over 3 months. Overall, miRNA expression was significantly higher in PBMC than in biopsy samples. Blood miR-21 expression was increased in untreated patients compared to controls and had a diagnostic value with an AUC of 0.78. After 6 weeks, it decreased significantly, similar to anti-Dsg1 antibodies and the PDAI score. In addition, a positive correlation was observed between cutaneous miR-21 expression and the disease activity score. Conversely, cutaneous expressions of miR-17, miR-146a and miR-155 were significantly higher in treated chronic patients compared to remittent ones. The cutaneous level of miR-155 positively correlated with pemphigus activity, making it a potential predictive marker for patients' clinical stratification with an AUC of 0.86.These findings suggest that blood miR-21 and cutaneous miR-155 can be used as supplemental markers for PF diagnosis and activity, respectively in addition to classical parameters.

The critical importance of epigenetics in autoimmune-related skin diseases

Autoimmune-related skin diseases are a group of disorders with diverse etiology and pathophysiology involved in autoimmunity. Genetics and environmental factors may contribute to the development of these autoimmune disorders. Although the etiology and pathogenesis of these disorders are poorly understood, environmental variables that induce aberrant epigenetic regulations may provide some insights. Epigenetics is the study of heritable mechanisms that regulate gene expression without changing DNA sequences. The most important epigenetic mechanisms are DNA methylation, histone modification, and noncoding RNAs. In this review, we discuss the most recent findings regarding the function of epigenetic mechanisms in autoimmune-related skin disorders, including systemic lupus erythematosus, bullous skin diseases, psoriasis, and systemic sclerosis. These findings will expand our understanding and highlight the possible clinical applications of precision epigenetics approaches.

Targeting TGF-β1/miR-21 pathway in keratinocytes reveals protective effects of silymarin on imiquimod-induced psoriasis mouse model

Epidermal cells integrate multiple signals that activate the signaling pathways involved in skin homeostasis. TGF-β1 signaling pathway upregulates microRNA (miR)-21-5p in keratinocytes and is often deregulated in skin diseases. To identify the bioactive compounds that enable to modulate the TGF-β1/miR-21-5p signaling pathway, we screened a library of medicinal plant extracts using our miR-ON RILES luciferase reporter system placed under the control of the miR-21-5p in keratinocytes treated with TGF-β1. We identified silymarin, a mixture of flavonolignans extracted from Silybum marianum (L.) Gaertn., as the most potent regulator of miR-21-5p expression. Using Argonaute 2 immunoprecipitation and RT-qPCR, we showed that silymarin regulates the expression of miR-21-5p through a noncanonical TGF-β1 signaling pathway, whereas RNA-sequencing analysis revealed three unexpected transcriptomic signatures associated with keratinocyte differentiation, cell cycle, and lipid metabolism. Mechanistically, we demonstrated that SM blocks cell cycle progression, inhibits keratinocyte differentiation through repression of Notch3 expression, stimulates lipid synthesis via activation of PPARγ signaling and inhibits inflammatory responses by suppressing the transcriptional activity of NF-κB. We finally showed that topical application of silymarin alleviates the development of imiquimod-induced psoriasiform lesions in mice by abrogating the altered expression levels of markers involved in inflammation, proliferation, differentiation, and lipid metabolism.

Intravenous As2O3 as a promising treatment for psoriasis - an experimental study in psoriasis-like mouse model

OBJECTIVE

To evaluate the efficacy and mechanistic bases of the intravenous injection of arsenic trioxide at clinical-relevant doses for treating an imiquimod-induced psoriasis-like mouse model.

METHODS

After inducing psoriasis-like skin lesions on the back of mice with imiquimod, mice in each group were injected with a clinical dose of arsenic trioxide through the tail vein. The changes in the gene expression, protein expression and distribution of relevant inflammatory factors were evaluated in the inflicted skin area, for mechanisms underlying the efficacy of intravenous As₂O₃ intervention. HaCaT cells were used to establish an in vitro psoriasis model and pcDNA3.1-NF-κB overexpression plasmid was transfected into cells to overexpress P65, which further confirmed the role of the NF-κB signaling pathway in the effectiveness of As₂O₃.

RESULTS

Clinical dose of As₂O₃ can significantly improve abnormal symptoms and pathological changes in psoriasis-like skin lesions induced by IMQ in mice. While IMQ induced abnormal expression and distribution of inflammatory factors in the RIG-I pathway and the microRNA-31 (miR-31) pathway in psoriatic skin tissues, intravenous As₂O₃ can effectively regulate and restore the normality. The leading role of NF-κB signaling was evidenced in vivo and validated in vitro using the NF-κB-overexpressed HaCaT cell model.

CONCLUSION

Clinical dosage of As₂O₃ may achieve effective treatment of IMQ-induced psoriatic skin lesions by modulating the NF-κB signaling pathway which regulates both the RIG-I and the miR-31 lines of action. Our data provided strong evidence supporting the claim that systemic As₂O₃ administration of clinical doses can be a promising treatment for psoriasis patients.

Possible Role of lncRNA MEG3-microRNA-21 and Endoplasmic Reticulum (ER) Stress Proteins in the Pathogenesis of Psoriasis Vulgaris

BACKGROUND

Psoriasis is a chronic inflammatory immune mediated disease arising from interaction between genetic risk variants and the environment. Maternally expressed gene3 (MEG3) is a long noncoding RNA (lncRNA) known for gene transcription regulation and inhibiting proliferation. MEG3 competes with microRNA (miRNA-21) influencing cell proliferation and apoptosis balance. Endoplasmic reticulum (ER) stress proteins promote cell survival via unfolded protein response (UPR) influenced by MEG3. We aimed to detect the possible role of MEG3, miRNA-21 and ER stress proteins in pathogenesis of psoriasis vulgaris.

METHODS

Human GRP78, ATF6, caspase3 tissue levels were assayed by Enzyme Linked Immunosorbent Assay (ELISA). Assessment of long non-coding MEG3 and miRNA 21 expressions was done by quantitative real time polymerase chain reaction (qRT-PCR).

RESULTS

Expression of MEG3 was significantly downregulated, while miRNA-21 was remarkably upregulated, ER stress proteins GRP78, ATF6, and caspase 3 all showed low levels in homogenized psoriatic lesions when compared to normal skin. miRNA 21 and MEG3 were identified as possible diagnostic markers for psoriasis vulgaris.

DISCUSSION

MEG3 is barely expressed in psoriatic lesions while miRNA-21 expression is remarkably elevated but when correlated to each other there was unexpected positive correlation. MEG3 and miRNA-21 were identified as possible diagnostic markers for psoriasis. Undifferentiated psoriatic lesions have very weak UPR.

Global circRNA expression changes predate clinical and histological improvements of psoriasis patients upon secukinumab treatment

Psoriasis is a common chronic inflammatory skin disease accompanied by heterogenous clinical and histological features, including a characteristic keratinocyte hyperproliferation and dermal immunogenic profile. In addition, psoriasis is associated with widespread transcriptomic alterations including changes in microRNA (miRNA) and circular RNA (circRNA) abundance, which constitute non-coding RNA (ncRNA) classes with specific regulatory capacities in diverse physiological and pathological processes. However, the knowledge about the expression dynamics of ncRNA during psoriasis treatment is sparse. To elucidate the dynamics of miRNA and circRNA abundance during secukinumab (anti-IL-17A) treatment, we studied their expression patterns in skin biopsies from 14 patients with severe plaque-type psoriasis before and during an 84-day secukinumab therapy at day 0, 4, 14, 42, and 84 using NanoString nCounter technology. We found a comprehensive downregulation of the majority of investigated circRNAs and specific alterations in the miRNA profile, including an upregulation of miR-203a-3p, miR-93-5p, and miR-378i in lesional compared to non-lesional skin before treatment. During treatment, the circRNAs progressively returned to the expression levels observed in non-lesional skin and already four days after treatment initiation most circRNAs were significantly upregulated. In comparison, for miRNAs, the normalization to baseline during treatment was delayed and limited to a subset of miRNAs. Moreover, we observed a strong correlation between multiple circRNAs, including ciRS-7 and circPTPRA, and the psoriasis area and severity index (PASI). Similar pronounced correlations could, however, not be found for miRNAs. Finally, we did not observe any significant changes in circRNA expression in peripheral blood mononuclear cells during treatment. In conclusion, we uncovered a rapid shift in global circRNA abundance upon anti-IL-17A treatment, which predated clinical and histological improvements, and a strong correlation with PASI, indicating a biomarker potential of individual circRNAs.

Peroxisome proliferator-activator receptor γ and psoriasis, molecular and cellular biochemistry

The pathophysiology of psoriasis is complex and has not been completely elucidated. Better understanding of the pathogenesis may contribute to further improvement of our therapeutic strategies controlling psoriasis. Emerging evidence points to a causative relationship between altered activity of peroxisome proliferator-activated receptor γ (PPARγ) and psoriasis. The present review focuses on deeper understanding of the possible role of PPARγ in the pathogenesis of psoriasis and the potential of PPARγ agonist to improve the treatment of psoriasis. PPARγ is decreased in psoriasis. PPARγ possibly has effects on the multiple aspects of the pathogenesis of psoriasis, including abnormal lipid metabolism, insulin resistance, immune cells, pro-inflammatory cytokines, keratinocytes, angiogenesis, oxidative stress, microRNAs and nuclear factor kappa B. As defective activation of PPARγ is involved in psoriasis development, PPARγ agonists may be promising agents for treatment of psoriasis. Pioglitazone appears an effective and safe option in the treatment of patients with psoriasis, but there are still concerns about its potential side effects. Research effort has recently been undertaken to explore the PPARγ-activating potential of natural products. Among them some have been studied clinically or preclinically for treatment of psoriasis with promising results.

Role of microRNAs in the Pathophysiology of Ulcerative Colitis

Ulcerative colitis (UC) is an intractable disorder characterized by a chronic inflammation of the colon. Studies have identified UC as a multifactorial disorder affected by both genetic and environmental factors; however, the precise mechanism remains unclear. Recent advances in the field of microRNA (miRNA) research have identified an association between this small non-coding RNA in the pathophysiology of UC and altered miRNA expression profiles in patients with UC. Nevertheless, the roles of individual miRNAs are uncertain due to heterogeneity in both research samples and clinical backgrounds. In this review, we focus on miRNA expression in colonic mucosa where inflammation occurs in UC and discuss the potential roles of individual miRNAs in disease development, outlining the pathophysiology of UC.

High-Throughput RNA Sequencing Reveals the Effect of NB-UVB Phototherapy on Major Inflammatory Molecules of Lesional Psoriasis

OBJECTIVE

To identify the narrowband ultraviolet B (NB-UVB)-induced molecular mechanisms that may account for their anti-inflammatory efficacy, gene expression and transcriptome profiling, which were performed using advanced molecular techniques.

METHODS

This research was conducted on patients with moderate-to-severe plaque-type psoriasis who received NB-UVB treatment. RNA sequencing (RNA-Seq) was conducted to assay the transcriptomes and identify the differentially expressed transcripts that had been enriched during the major pathway analysis.

RESULTS

Clinical improvement of psoriasis by NB-UVB therapy is linked to the suppression of the "immunological signaling pathways" and "cell cycle regulatory, growth and proliferation pathways" which are critical to the pathogenesis of the disease. In addition, these results were further substantiated by demonstrating that NB-UVB therapy has a significant effect on keratinocyte differentiation and affects the regulation of genes and inflammatory mediators that are related to cell proliferation and apoptosis. Moreover, NB-UVB phototherapy is also involved with the downregulation of toll-like receptors signaling in lesional psoriasis.

CONCLUSION

NB-UVB is an effective treatment for psoriasis. Our study supports the conclusion that the clinical effectiveness of NB-UVB therapy is based on the suppression of a broad range of inflammatory signaling pathways, gene expression of inflammatory cytokines and increased expressions of anti-inflammatory signaling pathways in psoriatic skin. This is the first study that applied advanced molecular techniques to investigate phototherapy as a new key to unlock genetic knowledge and create novel information. Ultimately, the goal is to increase medical knowledge and improve the patient care of psoriasis.

Circ-IGF1R plays a significant role in psoriasis via regulation of a miR-194-5p/CDK1 axis

Psoriasis is a skin disorder that is classed as an autoimmune disease. It is characterized by excessive proliferation, abnormal migration and differentiation of keratinocytes, as well as inflammatory cell infiltration. Circular RNAs (circRNAs/circ) have been reported to play an important role in several aspects of psoriasis. Thus in the present study, the role of circ-insulin-like growth factor 1 receptor (circ-IGF1R) in the development of psoriasis was assessed, and the involvement of microRNA (miR)-194-5p was also investigated as its expression was downregulated in psoriasis. StarBase analysis and dual luciferase reporter assays confirmed the interaction between circ-IGF1R with miR-194-5p. The increased expression of circ-IGF1R and decreased expression of miR-194-5p were further confirmed by reverse transcription-quantitative polymerase chain reaction in interleukin (IL-22)-stimulated HaCaT cells. The increased proliferation, migration and invasion, as well as decreased apoptosis, caspase 3 activity and cleaved-caspase 3/caspase 3 ratio were observed in IL-22-stimulated HaCaT cells. Conversely, transfection of circ-IGF1R-small interfering (si)RNA resulted in significantly increased expression of miR-194-5p with or without stimulation of IL-22 in HaCaT cells, and also overcame the effects of the miR-194-5p inhibitor. Additionally, transfection of circ-IGF1R-siRNA inhibited cell proliferation, migration and invasion, which were reversed by transfection of a miR-194-5p inhibitor. Similarly, circ-IGF1R-siRNA promoted apoptosis, caspase 3 activity and the cleaved-caspase 3/caspase 3 ratio, which were reversed by miR-194-5p inhibitor. These results showed that circ-IGF1R could affect the proliferation, apoptosis, migration and invasion of IL-22-stimulated HaCaT cells by regulating the expression of miR-194-5p. Based on TargetScan prediction and dual luciferase reporter assays, it was shown that cyclin-dependent kinase (CDK)1 was targeted by miR-194-5p. Additionally, the expression of CDK1 was upregulated following stimulation with IL-22 in HaCaT cells at the mRNA and protein levels. Transfection of miR-194-5p mimic or miR-194-5p inhibitor negatively regulated CDK1 expression in the IL-22 induced HaCaT cells. In conclusion, circ-IGF1R-siRNA could inhibit the cell proliferation, migration and invasion, and induce apoptosis by regulating the miR-194-5p/CDK1 axis. circ-IGF1R may thus serve as a potential treatment target for psoriasis.

MicroRNA-21 Regulates Diametrically Opposed Biological Functions of Regulatory T Cells

Regulatory T cells (Tregs) are considered important for controlling the onset and development of autoimmune disease. Although studies have shown that miR-21 is expressed at higher levels in Treg cells, it remains largely elusive whether miR-21 regulates the immune-suppressive function of Tregs. In the current study, we generated mice lacking miR-21 specifically in their Tregs and investigated the role of miR-21 in regulating Treg function both in vitro and in vivo. Our study revealed that Tregs lacking miR-21 exhibit normal phenotype and unaltered function in suppressing T cell proliferation and dendritic cell activation in vitro. However, compared with miR-21-sufficient Tregs, they produce significant more IL-17 and IL-10 when under pathogenic Th17-priming condition. Adenoviral delivery of miR-21 into Treg cells is able to reduce the expression of both IL-17 and IL-10. Mechanistic study revealed that miR-21 down-regulates IL-10 expression through direct targeting of IL-10, and suppresses reprogramming of Tregs into IL-17-secreting cells through down-regulating Stat3 activity. However, we detected no significant or marginal difference in the development of various autoimmune diseases between wild type mice and mice with Treg-specific deletion of miR-21. In conclusion, our study demonstrated that miR-21 in Tregs regulates diametrically opposed biological Treg functions and is largely dispensable for the development of autoimmune disease.

MicroRNA profiling of psoriatic skin identifies 11 miRNAs associated with disease severity

MicroRNAs (miRNAs) are small non-coding RNAs that have emerged as central regulators of gene expression and powerful biomarkers of disease. Much is yet unknown about their role in psoriasis pathology. To globally characterize the miRNAome of psoriatic skin, skin biopsies were collected from psoriatic cases (n = 75) and non-psoriatic controls (n = 46) and RNA sequenced. Count data were meta-analysed with a previously published dataset (cases, n = 24, controls, n = 20), increasing the number of psoriatic cases fourfold from previously published studies. Differential gene expression analyses were performed comparing lesional psoriatic (PP), non-lesional psoriatic (PN) and control (NN) skin. Further, functional enrichment and cell-specific analyses were performed. Across all contrasts, we identified 439 significantly differentially expressed miRNAs (DEMs), of which 85 were novel for psoriasis and 11 were related to disease severity. Meta-analyses identified 20 DEMs between PN and NN, suggesting an inherent change in the constitution of all skin in psoriasis. By integrating the miRNA transcriptome with mRNA target interactions, we identified several functionally enriched terms, including "thyroid hormone signalling," "insulin resistance" and various infectious diseases. Cell-specific expression analyses revealed that the upregulated DEMs were enriched in epithelial and immune cells. This study provides the most comprehensive overview of the miRNAome in psoriatic skin to date and identifies a miRNA signature related to psoriasis severity. Our results may represent molecular links between psoriasis and related comorbidities and have outlined potential directions for future functional studies to identify biomarkers and treatment targets.

miR-21 sustains CD28 signalling and low-affinity T-cell responses at the expense of self-tolerance

Objective

miR-21 is highly expressed in iNKT and activated T cells, but its T-cell autonomous functions are poorly defined. We sought to investigate the role of miR-21 in the development and functions of T and iNKT cells, representing adaptive and innate-like populations, respectively.

Methods

We studied mice with a conditional deletion of miR-21 in all mature T lymphocytes.

Results

Thymic and peripheral T and iNKT compartments were normal in miR-21 KO mice. Upon activation in vitro, miR-21 depletion reduced T-cell survival, T_H17 polarisation and, remarkably, T- and iNKT cell ability to respond to low-affinity antigens, without altering their response to high-affinity ones. Mechanistically, miR-21 sustained CD28-dependent costimulation pathways required to lower the T-cell activation threshold, inhibiting its repressors in a positive feedback circuit, in turn increasing T-cell sensitivity to antigenic stimulation and survival. Upon immunisation with the low-affinity self-epitope MOG_35-55, miR-21 KO mice were indeed less susceptible than WT animals to the induction of experimental autoimmune encephalomyelitis, whereas they mounted normal T-cell responses against high-affinity viral epitopes generated upon lymphocytic choriomeningitis virus infection.

Conclusion

The induction of T-cell responses to weak antigens (signal 1) depends on CD28 costimulation (signal 2). miR-21 sustains CD28 costimulation, decreasing the T-cell activation threshold and increasing their sensitivity to antigenic stimulation and survival, broadening the immune surveillance range. This occurs at the cost of unleashing autoimmunity, resulting from the recognition of weak self-antigens by autoreactive immune responses. Thus, miR-21 fine-tunes T-cell response and self-/non-self-discrimination.

miR-21-3p/IL-22 Axes Are Major Drivers of Psoriasis Pathogenesis by Modulating Keratinocytes Proliferation-Survival Balance and Inflammatory Response

Psoriasis is a chronic inflammatory skin disease that is mediated by complex crosstalk between immune cells and keratinocytes (KCs). Emerging studies have showed a specific psoriatic microRNAs signature, in which miR-21 is one of the most upregulated and dynamic miRNAs. In this study, we focused our investigations on the passenger miR-21-3p strand, which is poorly studied in skin and in psoriasis pathogenesis. Here, we showed the upregulation of miR-21-3p in an IMQ-induced psoriasiform mouse model. This upregulation was correlated with IL-22 expression and functionality, both in vitro and in vivo, and it occurred via STAT3 and NF-κB signaling. We identified a network of differentially expressed genes involved in abnormal proliferation control and immune regulatory genes implicated in the molecular pathogenesis of psoriasis in response to miR-21-3p overexpression in KCs. These results were confirmed by functional assays that validated the proliferative potential of miR-21-3p. All these findings highlight the importance of miR-21-3p, an underestimated miRNA, in psoriasis and provide novel molecular targets for therapeutic purposes.

Expression of microRNA-21 and TIMP-3 in paradoxical psoriasiform reactions during treatment with antitumor necrosis factor agents

BACKGROUND

Expression of microRNA-21 (miR-21) is increased in psoriasis, leading to reduced levels of epidermal tissue inhibitor of matrix metalloproteinase 3 (TIMP-3), a highly potent inhibitor of the tumor necrosis factor alpha (TNFα) sheddase TACE (TNFα-converting enzyme)/ADAM17. We described the profile of miR-21 and TIMP-3 in paradoxical psoriasiform reactions induced by anti-TNFα drugs and in a control group to elucidate the pathogenesis of this reactions.

METHODS

We performed an analytic, cross-sectional, prospective, experimental case-control study. We compared our findings with those of non-induced psoriasis.

RESULTS

We included 15 patients with a change of morphology (plaque to guttate psoriasis) and 10 patients with induced psoriasis (six palmoplantar pustulosis and four plaque psoriasis). Consecutive patients with different subtypes of non-induced, non-systemically treated psoriasis were included as a control group. We found that most cases with guttate psoriasis and with induced plaque psoriasis cases showed high expression of TIMP-3 expression and decreased or poorly increased levels of miR-21. The expression pattern was not homogeneous in the cases of induced palmoplantar pustulosis. These profiles differ from those of non-induced psoriasis.

CONCLUSION

We conclude that various pro-inflammatory cytokine profiles are involved in the pathogenesis of paradoxical psoriasiform reactions and non-induced psoriasis.

microRNAs involved in psoriasis and cardiovascular diseases

Psoriasis is a chronic inflammatory disease involving the skin. Both genetic and environmental factors play a pathogenic role in psoriasis and contribute to the severity of the disease. Psoriasis, in fact, has been associated with different comorbidities such as diabetes, metabolic syndrome, gastrointestinal or kidney diseases, cardiovascular disease (CVD), and cerebrovascular diseases (CeVD). Indeed, life expectancy in severe psoriasis is reduced by up to 5 years due to CVD and CeVD. Moreover, patients with severe psoriasis have a higher prevalence of traditional cardiovascular (CV) risk factors, including dyslipidemia, diabetes, smoking, and hypertension. Further, systemic inflammation is associated with oxidative stress increase and induces endothelial damage and atherosclerosis progression. Different miRNA have been already described in psoriasis, both in the skin tissues and in the blood flow, to play a role in the progression of disease. In this review, we will summarize and discuss the most important miRNAs that play a role in psoriasis and are also linked to CVD.

Cutaneous microRNA expression in healthy Labrador and Golden retrievers and retrievers with allergic and inflammatory skin diseases

BACKGROUND

MicroRNAs (miRNA) are short, single-stranded RNA molecules that regulate gene expression in a post-transcriptional manner. Their expression is proposed to be tissue-specific and alterations in miRNA expression have been detected in many diseases.

OBJECTIVE

To compare miRNA expression in the skin of healthy Labrador and golden retrievers, and those with allergic and nonallergic dermatitis.

METHODS AND MATERIALS

Formalin-fixed and paraffin-embedded (FFPE) skin specimens from seven healthy Labrador and golden retrievers, and seven dogs with allergic skin disease were collected. A further mixed nonallergic inflammation group consisted of samples from five dogs with fungal infection, demodicosis and mast cell tumours. Total RNA was extracted and miRNA primer assays for 18 target miRNAs (miR-142, miR-363, miR-18b, miR-451, miR-146a, miR-124, miR-409, miR-193b, miR-223, miR-215, miR-155, miR-423a, miR-143, miR-1839, miR-21, miR-34b, miR-146b and miR-202) were performed, with RNU6-2 and SNORD95 as miRNAs for normalisation. The selection of miRNAs for investigation was based on reported data and a pilot study evaluating miRNA extraction from FFPE tissue specimens.

RESULTS

In the two dogs with mast cell tumours, miRNA expression was undetermined for most miRNAs, so both were excluded from analysis. Although there were differences in the miRNA expression between healthy and inflamed skin, allergic and nonallergic inflammation showed similar expression patterns.

CONCLUSION AND CLINICAL RELEVANCE

Although the number of included dogs was small, based on this study, none of the evaluated miRNAs allowed differentiation of allergic dermatitis from other inflammatory skin diseases in retriever dogs.

Canonical and Interior Circular RNAs Function as Competing Endogenous RNAs in Psoriatic Skin

(1) Background: Understanding the function of circular RNAs (circRNAs), a class of noncoding RNA, in psoriatic skin can provide important insights into the complex regulation of genes contributing to the pathogenesis of psoriasis. (2) Methods: A novel method was applied to RNA-seq datasets from 93 skin biopsy samples to comprehensively identify circRNAs of all types, i.e., canonical circRNAs from the intron-exon junctions of mRNAs and interior circRNAs (i-circRNAs) from the interior regions of exons, introns, and intergenic regions. Selected circRNAs were experimentally validated by qRT-PCR and Sanger sequencing. CircRNAs with abundant and differential expression were identified and their putative function as competing endogenous RNAs (ceRNAs) was analyzed by an integrated analysis of circRNAs, microRNAs, and mRNAs. (3) Results: With a comprehensive search using no information of splicing signals, we systematically identified 179 highly abundant circRNAs in psoriatic skin. Many of these were reported for the first time and many were differentially expressed in involved versus normal or uninvolved skin. Validation based on three additional RNA-seq datasets confirmed most of the identified circRNAs in psoriatic skin. Experimental analyses confirmed the expression of the well-known circRNA CDR1as, a canonical circRNA, and a novel i-circRNA in psoriasis. We also identified many circRNAs that may act as ceRNAs to regulate the expression of mRNA genes in psoriasis-related signaling pathways in psoriasis. (4) Conclusions: The result of the study suggested that circRNAs are abundant in psoriatic skin, have distinct characteristics, and contribute to psoriatic pathogenesis.

Circulating microRNA profile unveils mechanisms of action of acitretin for psoriasis vulgaris

Psoriasis vulgaris is a common chronic and recurrent inflammatory skin disease. In clinical practice, acitretin is the first-line treatment drug for psoriasis vulgaris. MicroRNAs (miRNAs) play a vital role in the initiation and development of psoriasis vulgaris. However few studies focused on the mechanisms of acitretin in the treatment of psoriasis vulgaris from the perspective of miRNAs. Here, the expression profiles of circulating miRNAs in the plasma of 12 patients with psoriasis vulgaris before and after acitretin treatment were sequenced. Three miRNAs (miR-146a-5p, miR-122-5p and miR-21-5p) were identified using expression pattern analysis, and the levels were significantly decreased after acitretin treatment (P< 0.001). Receiver operating characteristic (ROC) analyses indicated that the three miRNAs have the potential to be utilized as molecular markers to evaluate the therapeutic effect of acitretin, and the values of the area under the curve (AUC) were 0.825, 0.831, and 0.796, respectively. In addition, we predicted target genes of the three miRNAs and performed signaling pathway enrichment analyses. The results demonstrated that the target genes were mainly involved in the MAPK, JAK-STAT, and NF-κB signaling pathways, which were further validated through in vitro experiments. In conclusion, acitretin can suppress miRNA-mediated MAPK, JAK-STAT, and NF-κB signaling pathways by decreasing miRNAs expression, thereby inhibiting the proliferation and inflammatory response of keratinocytes.

Upregulation of the miRNA-155, miRNA-210, and miRNA-20b in psoriasis patients and their relation to IL-17

Psoriasis is an immune-mediated disease, with genetic background and triggering environmental factors; however, several gaps are still present in understanding the intertwined relationship between these elements. Epigenetic mechanisms, including microRNAs (miRNAs), play an important role in the pathogenesis of psoriasis. The relationship between interleukin (IL)-17, a key cytokine in psoriasis, and these epigenetic mechanisms still needs to be elucidated. This study aimed at assessing the expression of miRNA-155, miRNA-210, and miRNA-20b in skin and sera of psoriasis patients in relation to IL-17 levels. For 20 psoriasis patients and 20 matching controls, the expression of miRNA-155, miRNA-210, and miRNA-20b was assessed using real-time polymerase chain reaction (RT-PCR), whereas IL-17/IL-17A levels were measured using quantitative enzyme-linked immunosorbent assay (ELISA) technique. MiRNA-155 expression was significantly higher in lesional skin compared to controls (P = 0.001). MiRNA-210 expression was significantly higher in both, lesional skin (P = 0.010) and sera of patients (P = 0.001) in comparison with controls. A statistically significant positive correlation was found between serum miRNA-210 expression and serum levels of IL-17/IL-17A (P = 0.010, rs = 0.562). MiRNA-20b lesional and non-lesional expression was significantly higher than controls (P < 0.001; P = 0.018). In conclusion, the expression of miRNA-155, miRNA-210, and miRNA-20b is exaggerated in psoriasis and they may be involved in disease pathogenesis. A possible relationship between miRNA-210 and IL-17 may be suggested; however, further studies are still needed to verify this relation.

miR-617 Promotes the Growth of IL-22-Stimulated Keratinocytes Through Regulating FOXO4 Expression

Psoriasis is considered as a common chronic and relapsing inflammatory skin disease. MicroRNAs (miRNAs) were found to be related with psoriasis pathogenesis. Nevertheless, the function of miR-617 in psoriasis is still unclear. The miR-617 RNA level was detected using quantitative reverse transcription-PCR (qRT-PCR). Western blot analysis examined the protein level. Cell proliferation was analyzed via cell counting kit-8 (CCK-8) assay. Flow cytometry analysis detected cell cycle and apoptosis. The relationship between miR-617 and forkhead box protein O4 (FOXO4) was confirmed through dual luciferase assay. The miR-617 was up-regulated in psoriatic skin tissues and interleukin-22 (IL-22)-stimulated immortalized human keratinocyte HaCaT cells. Moreover, miR-617 mimics promoted proliferation, cell cycle, and suppressed apoptosis in IL-22-stimulated HaCaT cells. However, miR-617 inhibitor showed opposite effects. Additionally, FOXO4 was a target of miR-617. FOXO4 was down-regulated in psoriatic skin tissues and IL-22-stimulated HaCaT cells. Negative correlation between miR-617 and FOXO4 was identified. FOXO4 overexpression alleviated the effects of miR-617 proliferation, cell cycle and apoptosis in the IL-22-stimulated HaCaT cells. These results demonstrate that miR-617 increases the growth of IL-22-stimulated keratinocytes through targeting FOXO4, which provides a new therapeutic target for psoriasis.

Cross-talk between IFN-γ and TWEAK through miR-149 amplifies skin inflammation in psoriasis

BACKGROUND

Psoriasis is a chronic inflammatory skin disease with disturbed interplay between immune cells and keratinocytes. A strong IFN-γ signature is characteristic for psoriasis skin, but the role of IFN-γ has been elusive. MicroRNAs are short RNAs regulating gene expression.

OBJECTIVE

Our aim was to investigate the role of miR-149 in psoriasis and in the inflammatory responses of keratinocytes.

METHODS

miR-149 expression was measured by quantitative RT-PCR in keratinocytes isolated from healthy skin and lesional and nonlesional psoriasis skin. Synthetic miR-149 was injected intradermally into the back skin of mice, and imiquimod was applied to induce psoriasis-like skin inflammation, which was then evaluated at the morphologic, histologic, and molecular levels. miR-149 was transiently overexpressed or inhibited in keratinocytes in combination with IFN-γ- and/or TNF-related weak inducer of apoptosis (TWEAK)-treatment.

RESULTS

Here we report a microRNA-mediated mechanism by which IFN-γ primes keratinocytes to inflammatory stimuli. Treatment with IFN-γ results in a rapid and long-lasting suppression of miR-149 in keratinocytes. Depletion of miR-149 in keratinocytes leads to widespread transcriptomic changes and induction of inflammatory mediators with enrichment of the TWEAK pathway. We show that IFN-γ-mediated suppression of miR-149 leads to amplified inflammatory responses to TWEAK. TWEAK receptor (TWEAKR/Fn14) is identified as a novel direct target of miR-149. The in vivo relevance of this pathway is supported by decreased miR-149 expression in psoriasis keratinocytes, as well as by the protective effect of synthetic miR-149 in the imiquimod-induced mouse model of psoriasis.

CONCLUSION

Our data define a new mechanism, in which IFN-γ primes keratinocytes for TWEAK-induced inflammatory responses through suppression of miR-149, promoting skin inflammation.

Mucosal microRNAs relate to age and severity of disease in ulcerative colitis

Despite significant evidence that the expression of several microRNAs (miRNAs) impacts disease activity in patients with ulcerative colitis (UC), it remains unknown if the more severe disease phenotype seen in pediatric onset UC can be explained by an altered miRNA expression. In this study, we assessed the relationship between miRNA expression, age, and disease severity in pediatric and adult patients with UC. Using RT-qPCR, we analyzed the expression of miR-21, miR-31, miR-126, miR-142 and miR-155 in paraffin embedded rectum biopsies from 30 pediatric and 30 adult-onset UC patients. We found that lesions from adult patients had significantly higher expression levels of miR-21 compared to pediatric patients and that the expression levels of miR-31 (all patients) and miR-155 (pediatric patients only) correlated inversely with histological assessed disease severity. Using in situ hybridization followed by image analysis, the expression level estimates of miR-21 and miR-126 correlated with histological assessed disease severity. In conclusion, we found that the expression of miRNAs depends on the age of the patient and/or the severity of the disease, suggesting that miRNAs may contribute to the regulation of inflammation in UC and could be useful biomarkers in the surveillance of disease severity.

Epigenetics in Non-tumor Immune-Mediated Skin Diseases

Epigenetics is the study of the mechanisms that regulate gene expression without modifying DNA sequences. Knowledge of and evidence about how epigenetics plays a causative role in the pathogenesis of many skin diseases is increasing. Since the epigenetic changes present in tumor diseases have been thoroughly reviewed, we believe that knowledge of the new epigenetic findings in non-tumor immune-mediated dermatological diseases should be of interest to the general dermatologist. Hence, the purpose of this review is to summarize the recent literature on epigenetics in most non-tumor dermatological pathologies, focusing on psoriasis. Hyper- and hypomethylation of DNA methyltransferases and methyl-DNA binding domain proteins are the most common and studied methylation mechanisms. The acetylation and methylation of histones H3 and H4 are the most frequent and well-characterized histone modifications and may be associated with disease severity parameters and serve as therapeutic response markers. Many specific microRNAs dysregulated in non-tumor dermatological disease have been reviewed. Deepening the study of how epigenetic mechanisms influence non-tumor immune-mediated dermatological diseases might help us better understand the role of interactions between the environment and the genome in the physiopathogenesis of these diseases.

miRNAs Flowing Up and Down: The Concerto of Psoriasis

Psoriasis is a chronic immune-mediated skin disease, whose hallmarks include keratinocyte hyperproliferation and CD4⁺ T cell subsets imbalance. Dysregulated microRNAs (miRNAs) identified in psoriasis have been shown to affect keratinocyte and T cell functions, with studies on the molecular mechanisms and intrinsic relationships of the miRNAs on the way. Here, we focus on the dysregulated miRNAs that contribute to the two hallmarks of psoriasis with the miRNA target genes confirmed. We review a network, in which, upregulated miR-31/miR-203/miR-155/miR-21 and downregulated miR-99a/miR-125b facilitate the excessive proliferation and abnormal differentiation of psoriatic keratinocytes; upregulated miR-210 and downregulated miR-138 work in concert to distort CD4⁺ T cell subsets balance in psoriasis. The miRNAs exert their functions through regulating key psoriasis-associated transcription factors including NF-κB and STAT3. Whether flowing up or down, these miRNAs collaborate to promote the development and maintenance of psoriasis.

Galectin-7 downregulation in lesional keratinocytes contributes to enhanced IL-17A signaling and skin pathology in psoriasis

Psoriasis is a chronic inflammatory skin disease characterized by inflammatory cell infiltration, as well as hyperproliferation of keratinocytes in skin lesions, and is considered a metabolic syndrome. We found that the expression of galectin-7 is reduced in skin lesions of patients with psoriasis. IL-17A and TNF-α, 2 cytokines intimately involved in the development of psoriatic lesions, suppressed galectin-7 expression in human primary keratinocytes (HEKn cells) and the immortalized human keratinocyte cell line HaCaT. A galectin-7 knockdown in these cells elevated the production of IL-6 and IL-8 and enhanced ERK signaling when the cells were stimulated with IL-17A. Galectin-7 attenuated IL-17A-induced production of inflammatory mediators by keratinocytes via the microRNA-146a/ERK pathway. Moreover, galectin-7-deficient mice showed enhanced epidermal hyperplasia and skin inflammation in response to intradermal IL-23 injection. We identified fluvastatin as an inducer of galectin-7 expression by connectivity map analysis, confirmed this effect in keratinocytes, and demonstrated that fluvastatin attenuated IL-6 and IL-8 production induced by IL-17A. Thus, we validate a role of galectin-7 in the pathogenesis of psoriasis, in both epidermal hyperplasia and keratinocyte-mediated inflammatory responses, and formulate a rationale for the use of statins in the treatment of psoriasis.

MicroRNAs in Several Cutaneous Autoimmune Diseases: Psoriasis, Cutaneous Lupus Erythematosus and Atopic Dermatitis

MicroRNAs (miRNAs) are endogenous small non-coding RNA molecules that regulate the gene expression at a post-transcriptional level and participate in maintaining the correct cell homeostasis and functioning. Different specific profiles have been identified in lesional skin from autoimmune cutaneous diseases, and their deregulation cause aberrant control of biological pathways, contributing to pathogenic conditions. Detailed knowledge of microRNA-affected pathways is of crucial importance for understating their role in skin autoimmune diseases. They may be promising therapeutic targets with novel clinical implications. They are not only present in skin tissue, but they have also been found in other biological fluids, such as serum, plasma and urine from patients, and therefore, they are potential biomarkers for the diagnosis, prognosis and response to treatment. In this review, we discuss the current understanding of the role of described miRNAs in several cutaneous autoimmune diseases: psoriasis (Ps, 33 miRNAs), cutaneous lupus erythematosus (CLE, 2 miRNAs) and atopic dermatitis (AD, 8 miRNAs). We highlight their role as crucial elements implicated in disease pathogenesis and their applicability as biomarkers and as a novel therapeutic approach in the management of skin inflammatory diseases.

Psoriasis: pathological mechanisms, current pharmacological therapies, and emerging drug delivery systems

Psoriasis is a chronic autoimmune skin disorder triggered by either genetic factors, environmental factors, life style, or a combination thereof. Clinical investigations have identified pathogenesis, such as T cell and cytokine-mediated, genetic disposition, antimicrobial peptides, lipocalin-2, galectin-3, vaspin, fractalkine, and human neutrophil peptides in the progression of psoriasis. In addition to traditional therapies, newer therapeutics, including phosphodiesterase type 4 (PDE4) inhibitors, Janus kinase (JAK) inhibitors, monoclonal antibodies (mAbs), gene therapy, anti-T cell therapy, and phytoconstituents have been explored. In this review, we highlight nanotechnology-related developments for psoriasis treatment, including patented delivery systems and therapeutics currently in clinical trials.

The Role of MicroRNAs in Epidermal Barrier

MicroRNAs (miRNAs), which mostly cause target gene silencing via transcriptional repression and degradation of target mRNAs, regulate a plethora of cellular activities, such as cell growth, differentiation, development, and apoptosis. In the case of skin keratinocytes, the role of miRNA in epidermal barrier integrity has been identified. Based on the impact of key genetic and environmental factors on the integrity and maintenance of skin barrier, the association of miRNAs within epidermal cell differentiation and proliferation, cell-cell adhesion, and skin lipids is reviewed. The critical role of miRNAs in the epidermal barrier extends the use of miRNAs for control of relevant skin diseases such as atopic dermatitis, ichthyoses, and psoriasis via miRNA-based technologies. Most of the relevant miRNAs have been associated with keratinocyte differentiation and proliferation. Few studies have investigated the association of miRNAs with structural proteins of corneocytes and cornified envelopes, cell-cell adhesion, and skin lipids. Further studies investigating the association between regulatory and structural components of epidermal barrier and miRNAs are needed to elucidate the role of miRNAs in epidermal barrier integrity and their clinical implications.

Pathogenesis of psoriasis in the "omic" era. Part III. Metabolic disorders, metabolomics, nutrigenomics in psoriasis

Psoriasis is a systemic disease that is strictly connected with metabolic disorders (insulin resistance, atherogenic dyslipidemia, arterial hypertension, and cardiovascular diseases). It occurs more often in patients with a more severe course of the disease. Obesity is specially an independent risk factor and it is associated with a worse treatment outcome because of the high inflammatory activity of visceral fatty tissue and the production of inflammatory mediators involved in the development of both psoriasis and metabolic disorders. However, in psoriasis the activation of the Th17/IL-17 and the abnormalities in the Th17/Treg balance axis are observed, but this pathomechanism does not fully explain the frequent occurrence of metabolic disorders. Therefore, there is a need to look for better biomarkers in the diagnosis, prognosis and monitoring of concomitant disorders and therapeutic effects in psoriasis. In addition, the education on the use of a proper diet as a prophylaxis for the development of the above disorders is an important element of holistic care for a patient with psoriasis. Diet may affect gene expression due to epigenetic modification which encompasses interactions of environment, nutrition and diseases. Patients with psoriasis should be advised to adopt proper diet and dietician support.

Serum MicroRNA Signature as a Diagnostic and Therapeutic Marker in Patients with Psoriatic Arthritis

OBJECTIVE

MicroRNA (miRNA) are small endogenous regulatory RNA molecules that have emerged as potential therapeutic targets and biomarkers in autoimmunity. Here, we investigated serum miRNA levels in patients with psoriatic arthritis (PsA) and further assessed a serum miRNA signature in therapeutic responder versus nonresponder PsA patients.

METHODS

Serum samples were collected from healthy controls (HC; n = 20) and PsA patients (n = 31), and clinical demographics were obtained. To examine circulatory miRNA in serum from HC and PsA patients, a focused immunology miRNA panel was analyzed utilizing a miRNA Fireplex assay (FirePlex Bioworks Inc.). MiRNA expression was further assessed in responders versus nonresponders according to the European League Against Rheumatism response criteria.

RESULTS

Six miRNA (miR-221-3p, miR-130a-3p, miR-146a-5p, miR-151-5p, miR-26a-5p, and miR-21-5p) were significantly higher in PsA compared to HC (all P < 0.05), with high specificity and sensitivity determined by receiver-operating characteristic curve analysis. Analysis of responder versus nonresponders demonstrated higher baseline levels of miR-221-3p, miR-130a-3p, miR-146a-5p, miR-151-5p, and miR-26a-5p were associated with therapeutic response.

CONCLUSION

This study identified a 6-serum microRNA signature that could be attractive candidates as noninvasive markers for PsA and may help to elucidate the disease pathogenesis.

miRNAs as Therapeutic Targets in Inflammatory Disease

In the past decade, we have witnessed considerable developments in understanding the roles and functions of miRNAs. In parallel, the identification of alterations in miRNA expression in inflammatory disease indicates their potential as therapeutic targets. Pharmacological treatments targeting abnormally expressed miRNAs for inflammatory diseases are not yet in clinical practice; however, some small compounds and nucleic acids targeting miRNAs have shown promise in preclinical development. Here, we focus on recent advances in understanding miRNA deregulation in inflammatory diseases and provide an overview of the current development of miRNA-based therapeutics in these diseases with an emphasis on newly discovered miRNA therapeutic targets.