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

Interleukins and Psoriasis

Psoriasis is an immune-mediated chronic inflammatory skin disease that affects 2% to 3% of the world's population. It is widely assumed that immune cells and cytokines acting together play a crucial part in the pathophysiology of psoriasis by promoting the excessive proliferation of skin keratinocytes and inflammatory infiltration. Interleukins (ILs), as a critical component of cytokines, have been closely associated with the pathogenesis and progression of psoriasis. This review summarizes the current contribution of ILs to psoriasis and describes the role each IL performs in psoriasis. Furthermore, the paper presents the therapeutic effects and application prospects of biologics developed for ILs in clinical treatment and experiments. The study aims to further the research on ILs in the treatment of psoriasis.

The Role of T Helper 22 Cells in Dermatological Disorders

T helper 22 (Th22) cells are a newly identified subset of CD4+ T cells that secrete the effector cytokine interleukin 22 (IL-22) upon specific antigen stimulation, barely with IFN-γ or IL-17. Increasing studies have demonstrated that Th22 cells and IL-22 play essential roles in skin barrier defense and skin disease pathogenesis since the IL-22 receptor is widely expressed in the skin, especially in keratinocytes. Herein, we reviewed the characterization, differentiation, and biological activities of Th22 cells and elucidated their roles in skin health and disease. We mainly focused on the intricate crosstalk between Th22 cells and keratinocytes and provided potential therapeutic strategies targeting the Th22/IL-22 signaling pathway.

TRAF3IP2 regulated by FOXO4 affects fibroblast proliferation, migration and extracellular matrix deposition in keloid through the TGF-β1/Smad pathway

BACKGROUND

Keloids are "tumor-like" scars that grow beyond the boundary of injury. Its pathogenesis is complex. This paper will discuss the pathogenesis of keloid from the transcriptional regulation mechanism of TRAF3IP2.

METHODS

IL-17 was utilized to induce human keloid fibroblasts (KFs) and normal dermal fibroblasts. With the application of RT-qPCR and Western blot, TRAF3IP2 expression was detected. . Subsequently, the expression of TRAF3IP2 was interfered by cell transfection and the effects of interfering TRAF3IP2 on cell proliferative rate, migration rate as well as extracellular matrix were assessed with CCK-8, Wound Healing, immunofluorescence as well as Western blot techniques. proliferation, migration and (ECM) deposition were detected by JASPAR software predicted the binding sites of transcription factors FOXO4 and TRAF3IP2 promoters. The relationship between FOXO4 and TRAF3IP2 was verified by Dual luciferase activity assay and ChIP. Finally, the expression of TRAF3IP2 and FOXO4 was interfered simultaneously to further explore the mechanism.

RESULTS

TRAF3IP2 was enhanced in IL-17 induced KFs. Interference with TRAF3IP2 imparted suppressive effects on the proliferation, migration as well as ECM deposition of KFs. FOXO4 could inhibit TRAF3IP2 transcription. And interference with FOXO4 reversed the effect of TRAF3IP2 downregulation on KFs via TGF-β1/Smad pathway.

CONCLUSION

TRAF3IP2 was regulated by FOXO4 and affected fibroblast proliferation, migration and ECM deposition in keloid through the TGF-β1/Smad pathway.

MicroRNA Alterations Induced in Human Skin by Diesel Fumes, Ozone, and UV Radiation

Epigenetic alterations are a driving force of the carcinogenesis process. MicroRNAs play a role in silencing mutated oncogenes, thus defending the cell against the adverse consequences of genotoxic damages induced by environmental pollutants. These processes have been well investigated in lungs; however, although skin is directly exposed to a great variety of environmental pollutants, more research is needed to better understand the effect on cutaneous tissue. Therefore, we investigated microRNA alteration in human skin biopsies exposed to diesel fumes, ozone, and UV light for over 24 h of exposure. UV and ozone-induced microRNA alteration right after exposure, while the peak of their deregulations induced by diesel fumes was reached only at the end of the 24 h. Diesel fumes mainly altered microRNAs involved in the carcinogenesis process, ozone in apoptosis, and UV in DNA repair. Accordingly, each tested pollutant induced a specific pattern of microRNA alteration in skin related to the intrinsic mechanisms activated by the specific pollutant. These alterations, over a short time basis, reflect adaptive events aimed at defending the tissue against damages. Conversely, whenever environmental exposure lasts for a long time, the irreversible alteration of the microRNA machinery results in epigenetic damage contributing to the pathogenesis of inflammation, dysplasia, and cancer induced by environmental pollutants.

Circ_0084443 Inhibits Wound Healing Via Repressing Keratinocyte Migration Through Targeting the miR-17-3p/FOXO4 Axis

Keratinocyte migration is a crucial process during skin wound healing, and circular RNAs are associated with keratinocyte migration. The purpose of our study was to clarify the role of circ_0084443 in wound healing. The levels of circ_0084443, microRNA (miR)-17-3p, and forkhead box protein O4 (FOXO4) were examined by quantitative reverse transcription-PCR. Cell migration was detected via wound scratch assay or transwell assay. The protein expression was measured using western blot. The binding analysis between miR-17-3p and circ_0084443 or FOXO4 was determined by dual-luciferase reporter assay and RNA Immunoprecipitation assay. TGF-β1 decreased the levels of circ_0084443 and FOXO4 while increased the miR-17-3p expression in keratinocytes by a concentration-dependent manner. Circ_0084443 acted as a miR-17-3p sponge and circ_0084443 overexpression alleviated TGF-β1-induced migration of keratinocytes by sponging miR-17-3p. FOXO4 was a target for miR-17-3p. The downregulation of miR-17-3p suppressed cell migration in TGF-β1-induced cells by increasing the FOXO4 level. Circ_0084443 positively regulated the FOXO4 expression by sponging miR-17-3p. Circ_0084443 suppressed the TGFβ signaling pathway by affecting the miR-17-3p/FOXO4 axis. These results exhibited that circ_0084443 suppressed the TGF-β1-induced keratinocyte migration by regulating the miR-17-3p/FOXO4 axis, suggesting the application potential of circ_0084443 in wound-healing-related diseases.

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.

CircRAB3B suppresses proliferation, motility, cell cycle progression and promotes the apoptosis of IL-22-induced keratinocytes depending on the regulation of miR-1228-3p/PTEN axis in psoriasis

INTRODUCTION

Psoriasis is an immune-related chronic skin disease, and interleukin-22 (IL-22) is involved in psoriasis pathogenesis through promoting proliferation and migration abilities of keratinocytes. Here, we analysed the role of circular RNA (circRNA) RAB3B, member RAS oncogene family (circRAB3B) in regulating the phenotypes of IL-22-induced HaCaT cells.

METHODS

RT-qPCR was implemented to assess RNA abundance. Western blot assay was adopted to assess protein abundance. Cell proliferation capacity was examined by cell counting kit-8 (CCK8) assay and 5-ethynyl-2'-deoxyuridine (Edu) assay. Cell motility was assessed by transwell assays and wound healing assay. Flow cytometric analysis was utilized to evaluate cell cycle progression and apoptosis. The intermolecular binding relations were tested via dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. CircRAB3B expression was reduced in psoriatic cutaneous specimens and IL-22-treated HaCaT cells.

RESULTS

CircRAB3B overexpression hampered the proliferation, motility, and cell cycle progression and elevated the apoptotic rate of IL-22-treated HaCaT cells, and circRAB3B silencing exhibited opposite effects in IL-22-induced HaCaT cells. CircRAB3B acted as microRNA-1228-3p (miR-1228-3p) sponge in HaCaT cells, and miR-1228-3p overexpression largely overturned circRAB3B overexpression-induced effects in HaCaT cells. MiR-1228-3p interacted with phosphatase and tensin homolog (PTEN), and circRAB3B sponged miR-1228-3p to induce PTEN level. MiR-1228-3p accumulation-mediated effects were partly alleviated by PTEN overexpression in HaCaT cells upon IL-22 treatment.

CONCLUSIONS

CircRAB3B suppressed psoriasis progression partly through down-regulating miR-1228-3p and up-regulating PTEN.