miR-320b Is Down-Regulated in Psoriasis and Modulates Keratinocyte Proliferation by Targeting AKT3

Emerging insights into the role of natural products and miRNAs in psoriasis: from pathophysiology to precision medicine

Psoriasis is a sustainable skin disease characterized by inflammation resulting from the interaction between immune cells and keratinocytes. Significant advancements have been achieved in studying the molecular process behind noncoding and coding genes, leading to valuable insights for clinical therapy. Nevertheless, our comprehension of this intricate ailment remains ambiguous. Natural products such as curcumin, vitamin D, omega-3, vitamin E, psoralen, gallic acid (GA), and resveratrol offer a promising alternative or adjunct therapy for psoriasis by modulating multiple pathways and exhibiting fewer side effects compared to conventional treatments. MicroRNAs (miRNAs) are short RNAs that are involved in regulating gene expression after transcription, namely by suppressing gene activity. Recent research on miRNAs has uncovered their significant significance in the development of psoriasis. In this review, we examined the latest developments in the investigation of miRNAs in psoriasis. Previous studies have revealed that imbalanced miRNAs in psoriasis have a significant impact on the processes of keratinocyte differentiation, proliferation, and the progression of inflammation. Furthermore, miRNAs exert an impact on the activity of immune cells involved in psoriasis, such as Langerhans cells, dendritic cells, and CD4+ T cells. Furthermore, we explore potential miRNA-focused treatment options for psoriasis, including the localized administration of external miRNA mimics, and miRNA inhibitors. The effectiveness of natural products and miRNAs in treating psoriasis, as well as the signaling pathways that may be involved, are summarized in this article.

Molecular mechanisms and drug therapy of metabolism disorders in psoriasis

Psoriasis is a prevalent skin disease affecting approximately 1%-3% of the population and imposes significant medical, social and economic burdens. Psoriasis involves multiple organs and is often complicated with obesity, diabetes, dyslipidemia, and hypertension. Because of the benefits of lipid-lowering agents and antidiabetic medications for psoriasis, metabolic abnormalities possibly play a pathogenic role in psoriasis.

This review focuses on the impacts of a variety of metabolic disorders on psoriasis and the underlying mechanisms.

In psoriasis, enhanced glycolysis, glutamine metabolism and altered fatty acid composition in the psoriatic lesion and plasma result in the excessive proliferation of keratinocytes and secretion of inflammatory cytokines. Altered metabolism is associated with the activation of MTORC signaling pathway and transcription factors such as HIF and S6K1. Therefore, MTORC1 can be a target for the treatment of psoriasis. Additionally, there are diabetes drugs and lipid-lowering drugs including TZDs, GLP-1 RAs, Metformin, statins and fibrates, which improve both metabolic levels and psoriasis symptoms.

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.

Downregulation of circ_0024028 inhibits IL-22-induced keratinocyte proliferation and migration by miR-486-3p/AKT3 axis

Circular RNA (circRNA) has been confirmed to participate in psoriasis process, but the role of circ_0024028 in psoriasis development is still unclear. Interleukin 22 (IL-22)-induced keratinocytes (HaCaT) were used to construct psoriasis cell models in vitro. The expression of circ_0024028, microRNA (miR)-486-3p and AKT serine/threonine kinase 3 (AKT3) was analyzed by quantitative real-time PCR. Cell function was assessed by cell counting kit 8 assay, EdU assay, transwell assay, and wound healing assay. Protein expression was examined using western blot analysis. RNA interaction was confirmed by dual-luciferase reporter assay and RIP assay. Exosomes were isolated from cell culture medium using ultracentrifugation and examined by transmission electron microscopy and nanoparticle tracking analysis. Circ_0024028 was highly expressed in psoriasis lesions and IL-22-induced HaCaT cells, and its silencing could inhibit IL-22-induced HaCaT cell proliferation and migration. MiR-486-3p could be sponged by circ_0024028, and its inhibitor restored the functions of circ_0024028 knockdown on IL-22-induced HaCaT cell proliferation and migration. AKT3 was targeted by miR-486-3p, and its overexpression reversed the inhibitory effect of miR-486-3p on IL-22-induced HaCaT cell proliferation and migration. AKT3 expression was positively regulated by circ_0024028, and circ_0024028/miR-486-3p/AKT3 axis could regulate the activity of AKT/mTOR pathway. Additionally, exosomes mediated the transfer of circ_0024028 in cells. Circ_0024028 might be a potential target for psoriasis treatment, which knockdown repressed IL-22-induced keratinocytes proliferation and migration through miR-486-3p/AKT3 pathway.

Early miR-320b and miR-25-3p miRNA levels correlate with multiple sclerosis severity at 10 years: a cohort study

BACKGROUND

Multiple sclerosis (MS) is a chronic demyelinating autoimmune disorder which may cause long-term disability. MicroRNA (miRNA) are stable, non-coding molecules that have been identified in our Comprehensive Longitudinal Investigation of Multiple Sclerosis at the Brigham and Women's Hospital (CLIMB)-cohort, as well as other international cohorts, as potential disease biomarkers in MS. However, few studies have evaluated the association of miRNA expression early in the MS disease course with long-term outcomes. Therefore, we aimed to evaluate the potential role of three candidate serum miRNAs previously correlated with MS disability in patients with MS, miR-320b, miR-25-3p and miRNA 486-5p, as early biomarkers of MS disability at 10-year follow-up.

MAIN BODY

We included 144 patients with serum obtained within three years of MS onset. miRNA expression was measured by RNA extraction followed by RT-PCR. Demographic, clinical, brain MRI and other biomarkers were collected. The primary outcome was the association between early miRNA expression and retaining benign MS, defined as EDSS ≤ 2 at 10-year follow-up. Among the 144 patients, 104 were benign and 40 were not benign at 10-year follow-up. 89 (62%) were women, with mean age at onset 37.7 (SD: 9.6) years. Patients who retained benign MS had lower values of miR-25-3p (p = 0.047) and higher miR-320b (p = 0.025) values. Development of SPMS was associated with higher miR-320b (p = 0.002) levels. Brain parenchymal fraction at year 10 was negatively correlated with miR-25-3p (p = 0.0004) and positively correlated with miR-320b (p = 0.006). No association was found between miR-486-5p and any outcome, and 10-year T2-lesion volume was not associated with any miRNA.

CONCLUSIONS

Our results show that miR-320b and miR-25-3p expression are early biomarkers associated with MS severity and brain atrophy. This study provides class III evidence of that miR-320b and miR-25-3p are associated with long-term MS disability which may be a potential tool to risk-stratify patients with MS for early treatment decisions.

Advances in pathogenesis and nanoparticles (NPs)-mediated treatment of psoriasis

Psoriasis is a chronic papulosquamous skin disease with an autoimmune pathogenic traits and strong genetic predisposition. In the past few decades, with the rapid development of molecular biology and cell biology, the inherent pathogenesis of psoriasis has been gradually elucidated, in which cytokine inflammatory loops, cell signaling pathways, and epigenetic factors such as miRNAs have been demonstrated to play important roles in regulating the development and progression of psoriasis. More importantly, understanding the pathogenesis of psoriasis has promoted the development of effective treatment for psoriasis. In this review, we systemically summarized the molecular mechanisms regulating the development and progression psoriasis, introduced various therapeutics used for clinical psoriasis therapy, and highlighted the recent advances in nanoparticles (NPs)-mediated drug delivery for psoriasis treatment.

Investigating melanogenesis-related microRNAs as disease biomarkers in vitiligo

Vitiligo is considered a disabling disease that affects physical, social, psychological, and occupational aspects of an individual's quality of life. The search for non-invasive and reliable biomarkers for vitiligo's early diagnosis, prognosis, and treatment prediction is under intensive investigation. There is currently an emerging interest in employing miRNAs as biomarkers to predict vitiligo diagnosis and prognosis, inspired by the well-preserved nature of miRNAs in serum or plasma. In the current study, we assessed a panel of 20 melanogenesis pathway-related microRNAs (miRNAs) using quantitative real-time PCR technique in 85 non-segmental vitiligo (NSV) patients compared to 85 normal controls followed by function and pathway enrichment analysis for the miRNAs with significant results. Twelve out of the 20 circulating miRNAs showed significantly higher expression levels in vitiligo patients relative to controls where miR-423 show the highest expression level followed by miR-182, miR-106a, miR-23b, miR-9, miR-124, miR-130a, miR-203a, miR-181, miR-152, and miR-320a. While six miRNAs (miR-224, miR-148a, miR-137, and miR-7, miR-148b, miR-145, miR-374b, and miR-196b) didn’t show significant expression level. The analysis of the receiver operating curve indicated that miR-423, miR-106a, and miR-182 were outstanding biomarkers with the highest areas under the curve in vitiligo. This study is the first Egyptian study to investigate a panel of miRNAs expression profile in the plasma of patients with NSV. Our results suggest that specific circulating miRNAs signature might be implicated in vitiligo pathogenesis and could potentially be used as biomarkers in vitiligo.

Identification of potential key molecules and signaling pathways for psoriasis based on weighted gene co-expression network analysis

BACKGROUND

Psoriasis is a chronic inflammatory skin disease, the pathogenesis of which is more complicated and often requires long-term treatment. In particular, moderate to severe psoriasis usually requires systemic treatment. Psoriasis is also associated with many diseases, such as cardiometabolic diseases, malignant tumors, infections, and mood disorders. Psoriasis can appear at any age, and lead to a substantial burden for individuals and society. At present, psoriasis is still a treatable, but incurable, disease. Previous studies have found that microRNAs (miRNAs) play an important regulatory role in the progression of various diseases. Currently, miRNAs studies in psoriasis and dermatology are relatively new. Therefore, the identification of key miRNAs in psoriasis is helpful to elucidate the molecular mechanism of psoriasis.

AIM

To identify key molecular markers and signaling pathways to provide potential basis for the treatment and management of psoriasis.

METHODS

The miRNA and mRNA data were obtained from the Gene Expression Omnibus database. Then, differentially expressed mRNAs (DEmRNAs) and differentially expressed miRNAs (DEmiRNAs) were screened out by limma R package. Subsequently, DEmRNAs were analyzed for Gene Ontology and Kyoto Encyclopedia of Genes and Genomics functional enrichment. The “WGCNA” R package was used to analyze the co-expression network of all miRNAs. In addition, we constructed miRNA-mRNA regulatory networks based on identified hub miRNAs. Finally, in vitro validation was performed. All experimental procedures were approved by the ethics committee of Chinese PLA General Hospital (S2021-012-01).

RESULTS

A total of 639 DEmRNAs and 84 DEmiRNAs were identified. DEmRNAs screening criteria were adjusted P (adj. P) value < 0.01 and |logFoldChange| (|logFC|) > 1. DEmiRNAs screening criteria were adj. P value < 0.01 and |logFC| > 1.5. KEGG functional analysis demonstrated that DEmRNAs were significantly enriched in immune-related biological functions, for example, toll-like receptor signaling pathway, cytokine-cytokine receptor interaction, and chemokine signaling pathway. In weighted gene co-expression network analysis, turquoise module was the hub module. Moreover, 10 hub miRNAs were identified. Among these 10 hub miRNAs, only 8 hub miRNAs predicted the corresponding target mRNAs. 97 negatively regulated miRNA-mRNA pairs were involved in the miRNA-mRNA regulatory network, for example, hsa-miR-21-5p-claudin 8 (CLDN8), hsa-miR-30a-3p-interleukin-1B (IL-1B), and hsa-miR-181a-5p/hsa-miR-30c-2-3p-C-X-C motif chemokine ligand 9 (CXCL9). Real-time polymerase chain reaction results showed that IL-1B and CXCL9 were up-regulated and CLDN8 was down-regulated in psoriasis with statistically significant differences.

CONCLUSION

The identification of potential key molecular markers and signaling pathways provides potential research directions for further understanding the molecular mechanisms of psoriasis. This may also provide new research ideas for the prevention and treatment of psoriasis in the future.

Immunomodulatory Properties of Human Breast Milk: MicroRNA Contents and Potential Epigenetic Effects

Infants who are exclusively breastfed in the first six months of age receive adequate nutrients, achieving optimal immune protection and growth. In addition to the known nutritional components of human breast milk (HBM), i.e., water, carbohydrates, fats and proteins, it is also a rich source of microRNAs, which impact epigenetic mechanisms. This comprehensive work presents an up-to-date overview of the immunomodulatory constituents of HBM, highlighting its content of circulating microRNAs. The epigenetic effects of HBM are discussed, especially those regulated by miRNAs. HBM contains more than 1400 microRNAs. The majority of these microRNAs originate from the lactating gland and are based on the remodeling of cells in the gland during breastfeeding. These miRNAs can affect epigenetic patterns by several mechanisms, including DNA methylation, histone modifications and RNA regulation, which could ultimately result in alterations in gene expressions. Therefore, the unique microRNA profile of HBM, including exosomal microRNAs, is implicated in the regulation of the genes responsible for a variety of immunological and physiological functions, such as FTO, INS, IGF1, NRF2, GLUT1 and FOXP3 genes. Hence, studying the HBM miRNA composition is important for improving the nutritional approaches for pregnancy and infant's early life and preventing diseases that could occur in the future. Interestingly, the composition of miRNAs in HBM is affected by multiple factors, including diet, environmental and genetic factors.

SNAI2-Induced CircMTO1 Promotes Cell Proliferation and Inhibits Apoptosis Through the miR-320b/MCL1 Axis in Human Granulosa-Like Tumor Cells

Polycystic ovary syndrome (PCOS), one of the most common types of endocrine diseases, is characterized by a high prevalence among women of reproductive-age. However, its pathogenesis and molecular mechanisms remain unclear. CircMTO1 has been reported to participate in numerous biological processes, but, its role in PCOS progression remains unknown. In the current study, we elucidated the expression and circRNA characterization of circMTO1 in human granulosa-like tumor cells. We found that circMTO1 knockdown promoted human granulosa-like tumor cell proliferation and inhibited its apoptosis rate. Next, we explored the underlying molecular mechanisms by using a series of experiments. Our results revealed the effect of the novel circMTO1/miR-320b/MCL1 axis in human granulosa-like tumor cells. Furthermore, we found that the expression of circMTO1 was induced by Snail family transcriptional repressor 2 (SNAI2) in human granulosa-like tumor cells. Our results may provide potential targets for PCOS research and a novel direction for the diagnosis and treatment of PCOS.

Dysregulated epigenetic modifications in psoriasis

The observed incidence of psoriasis has been gradually increasing over time (J Am Acad Dermatol, 03, 2009, 394), but the underlying pathogenic factors have remained unclear. Recent studies suggest the importance of epigenetic modification in the pathogenesis of psoriasis. Aberrant epigenetic patterns including changes in DNA methylation, histone modifications and non-coding RNA expression are observed in psoriatic skin. Reversing these epigenetic mechanisms has showed improvement in psoriatic phenotypes, making epigenetic therapy a potential avenue for psoriasis treatment. Here, we summarize relevant evidence for epigenetic dysregulation contributing to psoriasis susceptibility and pathogenesis, and the factors responsible for epigenetic modifications, providing directions for potential future clinical avenues.

Mir-320b Inhibits Pancreatic Cancer Cell Proliferation by Targeting FOXM1

BACKGROUND

Pancreatic Ductal Adenocarcinoma (PDAC) is the most common and deadly cancer. Surgical resection is the only possible cure for pancreatic cancer but often has a poor prognosis, and the role of adjuvant therapy is urgently explored.

METHODS

MicroRNAs (miRNAs) play a very important role in tumorigenesis by regulating the target genes. In this study, we identified miR-320b lower-expressed in human pancreatic cancer tissues but relatively higher-expressed in the adjacent non-tumor tissues.

RESULTS

Consistently, the expression of miR-320b in different pancreatic cancer cell lines was significantly lower than the normal pancreatic cells. In order to identify the effects of miR-320b on cell growth, we overexpressed miR-320b in PANC-1 and FG pancreatic cancer cell lines, CCK8 and BrdU incorporation assay results showed that miR-320b inhibited cell proliferation.

DISCUSSION

We next predicted miR-320b targeted FOXM1 (Forkhead box protein M1) and identified the negative relationship between miR-320b and FOXM1. We also demonstrated that elevated miR- 320b expression inhibited tumor growth in vivo.

CONCLUSION

All of these results showed that miR-320b suppressed pancreatic cancer cell proliferation by targeting FOXM1, which might provide a new diagnostic marker for pancreatic cancer.

MicroRNA as Potential Biomarkers of Platelet Function on Antiplatelet Therapy: A Review

MicroRNAs (miRNAs) are small, non-coding RNAs, able to regulate cellular functions by specific gene modifications. Platelets are the major source for circulating miRNAs, with significant regulatory potential on cardiovascular pathophysiology. MiRNAs have been shown to modify the expression of platelet proteins influencing platelet reactivity. Circulating miRNAs can be determined from plasma, serum, or whole blood, and they can be used as diagnostic and prognostic biomarkers of platelet reactivity during antiplatelet therapy as well as novel therapeutic targets in cardiovascular diseases (CVDs). Herein, we review diagnostic and prognostic value of miRNAs levels related to platelet reactivity based on human studies, presenting its interindividual variability as well as the substantial role of genetics. Furthermore, we discuss antiplatelet treatment in the context of miRNAs alterations related to pathways associated with drug response.

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.

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.

Study on Targeting Relationship Between miR-320b and FGD5-AS1 and Its Effect on Biological Function of Osteosarcoma Cells

Objective

To probe into the expression of FGD5-AS1 in osteosarcoma and its relationship with miR-320b.

Methods

The tissue and serum samples of 97 patients with osteosarcoma were collected, and the serum samples of 100 healthy subjects who concurrently underwent physical examination were selected as the control. FGD5-AS1 expression in tissues and serum was detected, and osteosarcoma cells were transfected to measure cell behaviors such as proliferation, invasion and apoptosis.

Results

FGD5-AS1 was highly expressed in osteosarcoma, and its elevated expression indicated poor survival of patients. Serum FGD5-AS1 was related to tumor size and clinical stage and could be used for the diagnosis of osteosarcoma. The study of osteosarcoma cell lines U2OS and SaOS-2 showed that after inhibiting FGD5-AS1, the viability and invasion capacity of osteosarcoma cells decreased statistically compared with the control group (CG), while the apoptosis ability could be improved by further regulating apoptotic proteins (P<0.05). Detection of EMT-related proteins identified that E-cadherin increased while N-cadherin decreased significantly after FGD5-AS1 inhibition (P<0.05). Correlation analysis revealed a negative correlation between miR-320b and FGD5-AS1 (r = −0.410, P<0.001). Overexpression of miR-320b significantly inhibited cell viability, invasion and EMT ability, and increased the apoptosis rate, while inhibiting miR-320b expression produced the opposite results. The targeting relationship between miR-320b and FGD5-AS1 was confirmed through the biological prediction website, luciferase assay and RNA binding protein immunoprecipitation (RIP) assay. Inhibition of miR-320b could reverse the regulatory effect of FGD5-AS1 knockdown on osteosarcoma cells.

Conclusion

FGD5-AS1 is highly expressed in osteosarcoma and is involved in the biological procession of osteosarcoma by targeting miR-320b.

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.

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.

Construction of a lncRNA-miRNA-mRNA network to determine the regulatory roles of lncRNAs in psoriasis

Psoriasis is a chronic inflammatory skin disorder that impairs the quality of life of affected patients. Emerging studies indicate that certain long non-coding RNAs (lncRNAs) have important roles in psoriasis. However, the exact functions of lncRNAs and their regulatory mechanisms as competitive endogenous RNAs (ceRNAs) in psoriasis have remained to be fully elucidated. In the present study, differentially expressed lncRNAs, microRNAs (miRNAs) and mRNAs were identified by analyzing public datasets, and a psoriasis-associated lncRNA-miRNA-mRNA network was constructed based on the ceRNA theory. Furthermore, previously validated abnormally expressed miRNAs in psoriasis were identified by a systematic literature search in the PubMed and Web of Science databases, and a specific miRNA-associated lncRNA-miRNA-mRNA sub-network was extracted. Furthermore, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed using DAVID 6.8. A total of 253 lncRNAs, 106 miRNAs and 1,156 mRNAs were identified as being differentially expressed between psoriasis skin and healthy control skin. The present study identified two key lncRNAs that may potentially have a role in the pathogenesis of psoriasis: AL035425.3 and Prader Willi/Angelman region RNA 6. This integrative analysis enhances the understanding of the molecular mechanism of psoriasis and may provide novel therapeutic targets for the treatment of psoriasis.

MiR-125b-5p and miR-181b-5p inhibit keratinocyte proliferation in skin by targeting Akt3

MicroRNAs (miRNAs) have been widely accepted to play important roles in the regulation of keratinocyte functions. Here, we aimed to further explore the role and underlying mechanism of miR-125b-5p and miR-181b-5p in psoriasis. The expression levels of miR-125b-5p, miR-181b-5p and Akt3 mRNA were detected by qRT-PCR assay. Cell proliferation ability was determined by MTT assay and BrdU incorporation assay. Dual-luciferase reporter assay and RNA Immunoprecipitation assay were used to confirm the targeted interaction between miR-125b-5p or miR-181b-5p and Akt3 in human epidermal keratinocytes (HEKs). The levels of ki-67, Akt3 protein, Akt, p-Akt, mTOR and p-mTOR were measured by Western blot. Our study indicated that miR-125b-5p and miR-181b-5p were downregulated (about 61.3% with miR-125b-5p and 60.4% with miR-181b-5p) and Akt3 was upregulated (about 2.68-fold) in psoriasis. Upregulation of miR-125b-5p or miR-181b-5p resulted in about a 33% or 40% reduction of HEKs proliferation in vitro, while Akt3 overexpression triggered a 1.3-fold enhancement on HEKs proliferation. Akt3 was a direct target of miR-125b-5p or miR-181b-5p. Moreover, HEKs proliferation ability in cotransfection of miR-125b-5p mimics (or miR-181-5p mimics) and vector-Akt3 group was about 2-fold (or 1.98-fold) that in the miR-125b-5p mimics (or miR-181-5p mimics) alone group. Akt/mTOR signaling was involved in miR-125b-5p mimics- or miR-181b-5p mimics-mediated inhibition effect on HEKs proliferation. Our study suggested that the upregulation of miR-125b-5p or miR-181b-5p inhibited HEKs proliferation at least partly by targeting Akt3, providing novel mechanisms of miRNAs involved in psoriasis.