Regulates Keratinocyte Proliferation Research Articles

Transcriptome Profiling Unveils Key Genes Regulating the Growth and Development of Yangzhou Goose Knob.

Goose is one of the most economically valuable poultry species and has a distinct appearance due to its possession of a knob. A knob is a hallmark of sexual maturity in goose (Anser cygnoides) and plays crucial roles in artificial selection, health status, social signaling, and body temperature regulation. However, the genetic mechanisms influencing the growth and development of goose knobs remain completely unclear. In this study, histomorphological and transcriptomic analyses of goose knobs in D70, D120, and D300 Yangzhou geese revealed differential changes in tissue morphology during the growth and development of goose knobs and the key core genes that regulate goose knob traits. Observation of tissue sections revealed that as age increased, the thickness of the knob epidermis, cuticle, and spinous cells gradually decreased. Additionally, fat cells in the dermis and subcutaneous connective tissue transitioned from loose to dense. Transcriptome sequencing results, analyzed through differential expression, Weighted Gene Co-expression Network Analysis (WGCNA), and pattern expression analysis methods, showed D70-vs.-D120 (up-regulated: 192; down-regulated: 423), D70-vs.-D300 (up-regulated: 1394; down-regulated: 1893), and D120-vs.-D300 (up-regulated: 1017; down-regulated: 1324). A total of 6243 differentially expressed genes (DEGs) were identified, indicating varied expression levels across the three groups in the knob tissues of D70, D120, and D300 Yangzhou geese. These DEGs are significantly enriched in biological processes (BP) such as skin morphogenesis, the regulation of keratinocyte proliferation, and epidermal cell differentiation. Furthermore, they demonstrate enrichment in pathways related to goose knob development, including ECM-receptor interaction, NF-kappa B, and PPAR signaling. Through pattern expression analysis, three gene expression clusters related to goose knob traits were identified. The joint analysis of candidate genes associated with goose knob development and WGCNA led to the identification of key core genes influencing goose knob development. These core genes comprise WNT4, WNT10A, TCF7L2, GATA3, ADRA2A, CASP3, SFN, KDF1, ERRFI1, SPRY1, and EVPL. In summary, this study provides a reference for understanding the molecular mechanisms of goose knob growth and development and provides effective ideas and methods for the genetic improvement of goose knob traits.

Abstract 1799: Regulation of epidermal stem cell proliferation and adhesion by ACSS2

Abstract Acetyl-CoA Synthetase Short-Chain Family Member 2 (ACSS2) is an enzyme that converts acetate into acetyl-CoA, a crucial metabolite required for protein acetylation and lipogenesis. Acetyl-CoA is membrane-impermeable and must be synthesized in the compartment in which it will be used. Among ACSS enzymes, ACSS2 alone is found in the nucleocytoplasmic compartment rather than the mitochondria. This enzyme shows dynamic localization dependent on cell nutrient status, with nutrient stress promoting nuclear localization where ACSS2 activity promotes cell growth and survival. Emerging evidence suggests ACSS2 may also play roles in promoting metastasis, and has been proposed as a potential therapeutic target. However, the role of ACSS2 in controlling normal tissue homeostasis is understudied. Addressing this knowledge gap is critical to ensure safety and efficacy of cancer therapeutics. As 80% to 90% of human cancers originate from epithelial tissues, we have leveraged human epidermal stem cells to further interrogate the role of ACSS2. As progenitor keratinocytes differentiate, they detach from the basal lamina and migrate from the metabolically privileged basal layer to the more challenging environment at the surface of the epidermis. Using shRNA-mediated knockdown, we first found ACSS2 knockdown dramatically decreases progenitor keratinocyte clonogenicity, abolishing proliferative capacity. Analysis of RNA sequencing data following ACSS2 knockdown with five constructs showed significant increases in expression of genes related to cell adhesion, extracellular matrix organization, collagen catabolism, and cell migration, in addition to keratinocyte differentiation. Downregulated genes were associated with cell division, DNA repair, and DNA replication. Live cell imaging revealed knockdown cells show striking differences in cell adhesion compared to control. These results indicate a role for ACSS2 in regulating keratinocyte proliferation and adhesion during the maintenance of epidermal homeostasis. Citation Format: Nicholas K. Chamberlain, Xiaomin Bao. Regulation of epidermal stem cell proliferation and adhesion by ACSS2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1799.

Qinzhuliangxue mixture ameliorates psoriasis by restraining apoptosis in psoriasis via downregulating the MDA-5 pathway

Ethnopharmacological relevancePsoriasis is characterized by hyperkeratosis that produces the classic silvery scales, and the pathogenesis of psoriasis involves abnormal proliferation of keratinocytes. Emerging evidence supports that apoptosis regulates keratinocyte proliferation and formation of stratum corneum, which maintains the homeostasis of the skin. Qinzhuliangxue mixture (QZLX) is a representative formula for the treatment of psoriasis, which was earliest recorded in the classic Chinese medicine book Xia's Surgery. In our previous clinical studies, QZLX demonstrated 83.33% efficacy with few side effects in the treatment of psoriasis. Furthermore, our published basic research has also proved that the QZLX mixture effectively inhibits the hyperproliferation of keratinocytes, thus exerting therapeutic effects on psoriasis. However, whether QZLX mixture can regulate keratinocytes apoptosis requires further clarification. Objective of the studyTo investigate the mechanism of QZLX in the treatment of psoriasis from the perspective of keratinocyte apoptosis. Materials and methodsFirst, psoriasis-like mice with imiquimod (IMQ)-induced were given QZLX intragastric administration and Psoriasis Area Severity Index (PASI) scores were recored for 11 consecutive days to appraise the efficacy. Then, tissue samples were collected for transcriptome analysis. The DEseq2 method detected significantly differentially expressed genes (DEGs), Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway databases were used to analyze the functions and pathway enrichment of DEGs. After that, the therapeutic mechanisms of QZLX in intervening with psoriasis were explored using TUNEL, immunohistochemical staining, and western blotting. ResultsQZLX ameliorated the symptoms and pathological characteristics of IMQ-induced psoriasis in mice. The epidermal cell hyperplasia in the skin was inhibited, in accordance with the suppressed expression of PCNA and Ki67 after treatment. Transcriptome sequencing showed that melanoma differentiation associated gene-5 (MDA-5) was downregulated. GO and KEGG enrichment analysis of the signaling pathways indicated that the differentially expressed genes were significantly enriched in apoptosis pathways. Besides, QZLX treatment decreased the apoptosis of keratinocyte as shown by reduced TUNEL-positive cells. As MDA-5 protein levels decreased, so did the expression of the downstream protein Caspase-8, which indicates that the apoptotic pathway was triggered. Furthermore, QZLX therapy might also help to balance the apoptotic Bcl-2 family expression. ConclusionQZLX restrains the apoptosis of keratinocyte in psoriasis-like mice by downregulating the MDA-5 pathway. The restoration of the balance between cell apoptosis and proliferation in the skin may lead to considerable psoriasis relief. Our study reveals the possible molecular processes behind the effects of QZLX therapy on the skin lesions of psoriasis, and lends support to its clinical efficacy.

Cold atmospheric plasma for chronic kidney disease-related skin disorders.

An estimated 80% of individuals with chronic kidney disease (CKD) experience concomitant skin disorders, yet experimental research that elucidates the pathological changes in CKD-affected skin is limited. Cold atmospheric plasma (CAP) has shown promise in regulating keratinocyte proliferation, skin barrier function, and anti-inflammatory activity. We hypothesize that CAP emerges as a promising therapeutic avenue for CKD-related skin diseases. Male and female C57/BL6 mice were administered a 0.2% adenine diet to generate a CKD mouse model. Skin samples from dialysis patients were also collected. These models were used to investigate the pathological alterations in the renal glomeruli, tubules, and epidermis. Subsequently, the potential impact of CAP on the stratum corneum, keratinocytes, skin hydration, and inflammation in mice with CKD were examined. Renal biopsies revealed glomerular and tubular atrophy, epithelial degeneration and necrosis in uriniferous tubules, and significant renal interstitial fibrosis. Skin biopsies from patients with CKD and mice showed stratum corneum thickening, epidermis atrophy, skin hydration dysfunction, and excessive inflammation. CAP attenuated skin atrophy, hydration dysfunction, and inflammation in mice with CKD, as evidenced by the activated level of YAP1/β-catenin and Nrf-2/OH-1, enhanced expression of K5 and Ki67, increased levels of AQP3, collagen I, and GLUT1, reduced infiltration of CD3+ T cells, and diminished levels of IL-6 and TNF-α. This study provides valuable insights into the pathological changes in skin associated with CKD in both patients and animal models. It also establishes that CAP has the potential to effectively mitigate skin atrophy, hydration dysfunction, and inflammation, suggesting a novel therapeutic avenue for the treatment of CKD-related skin disorders.

IL-6 Up-Regulates Expression of LIM-Domain Only Protein 4 in Psoriatic Keratinocytes through Activation of the MEK/ERK/NF-κB Pathway

Psoriasis is a chronic inflammatory skin disease characterized by the activation of keratinocytes and the infiltration of immune cells. Overexpression of the transcription factor LIM-domain only protein 4 (LMO4) promoted by interleukin-23 (IL-23) has critical roles in regulating the proliferation and differentiation of psoriatic keratinocytes. IL-6, an autocrine cytokine in psoriatic epidermis, is a key mediator of IL-23/T helper (Th17)-driven cutaneous inflammation. However, little is known about how IL-6 regulates the upregulation of LMO4 expression in psoriatic lesions. In this study, human immortalized keratinocyte (HaCaT) cells, clinical biopsy specimens, and an animal model of psoriasis induced by imiquimod cream were used to investigate the role of IL-6 in the regulation of keratinocyte proliferation and differentiation. We found that IL-6 and LMO4 were abnormally expressed in the psoriatic epidermis. IL-6 up-regulates the expression of LMO4 and promotes keratinocyte proliferation and differentiation. Furthermore, in vitro and in vivo studies showed that IL-6 upregulates LMO4 expression by activating the MEK/ERK/NF-κB signaling pathway. These results suggest that IL-6 can activate the NF-κB signaling pathway, upregulate the expression of LMO4, lead to abnormal proliferation and differentiation of keratinocytes, and promote the occurrence and development of psoriasis.

Epidermal turnover and iron metabolism in senile lentigo.

Senile lentigo (SL) is a pigmentary disorder associated with disrupted epidermal turnover. Trace minerals in the skin are known to regulate keratinocyte proliferation and differentiation. To clarify the role of iron in SL, we compared the expression of molecules related to iron metabolism between SL lesion (lesion) and the surrounding normal skin (nonlesion). Our results revealed that proteins involved in iron uptake and utilization such as transferrin receptor 1, iron regulatory protein 1, mitoferrin 1, and divalent metal transporter 1 were expressed in the lower epidermis in the nonlesion, while expression of them was also observed in the upper epidermis in the lesion. Ferroportin (FPN), involved in iron export, was expressed in the upper epidermis in the nonlesion, but was only scarcely expressed in the upper epidermis in the lesion. Hepcidin, which promotes FPN degradation, was expressed in the lower epidermis in the nonlesion; however, its expression was also observed in the upper epidermis in the lesion. These changes in the expression of molecules involved in iron uptake/export/utilization might reflect the altered iron utilization state in SL, resulting in disruption of keratinocyte differentiation and disturbing epidermal turnover. Our results suggest that the metabolism of iron in keratinocytes in SL differs from that in the normal epidermis, and these changes could be associated with the abnormal epidermal turnover and decreased melanin excretion in SL.

Pro-inflammatory cytokine IL-6 regulates LMO4 expression in psoriatic keratinocytes via AKT/STAT3 pathway.

The transcription factor LIM-only protein 4 (LMO4) is overexpressed in the psoriatic epidermis and regulates keratinocyte proliferation and differentiation. High LMO4 expression levels are induced by interleukin-23 (IL-23) to activate the AKT/STAT3 signaling pathway. Interleukin-6 (IL-6) is mainly involved in regulating T cell functions and development in patients with psoriasis. However, whether LMO4 expression is regulated by IL-6 remains unclear. Therefore, the purpose of this study is to explore the role and molecular mechanisms of IL-6 in regulating LMO4 expression. The interleukin-6 (IL-6) levels in human plasma were determined using a chemiluminescence immunoassay system. A psoriasis-like mouse model was established using imiquimod induction. Epidermal keratinocytes (HaCaT) were cultured in defined keratinocyte-serum-free medium and stimulated by IL-6 alone or with inhibitors. The proteins of interest were detected using western blot analysis, immunofluorescence, and immunohistochemistry. The 5-ethynyl-2'-deoxyuridine assay was used to detect cell proliferation. The results revealed that IL-6 levels were markedly increased in the plasma of patients with psoriasis, compared to healthy control. The high expression of LMO4 was consistent with high levels of IL-6, p-AKT, and p-STAT3 in the lesions of both psoriasis patients and imiquimod-induced psoriasis-like mice. IL-6 activates the AKT/STAT3 signaling pathway, followed by LMO4 high-expression in HaCaT cells. IL-6 induces HaCaT proliferation and differentiation via AKT/STAT3 signaling pathway activation. We think that the high expression of LMO4 in psoriatic keratinocytes requires IL-6 to activate the AKT/STAT3 signaling pathway and leads to epidermal keratinocytes abnormal proliferation and differentiation.

LncRNA H19 Inhibits Keratinocyte Cell Proliferation and Migration by Targeting miR-17-5p/RUNX1 Axis in Chronic Wounds.

The migration and proliferation of keratinocytes are critical for re-epithelization during chronic wound healing. Runt-related transcription factor 1 (RUNX1) has been indicated to repress keratinocyte proliferation. Nonetheless, the potential molecular mechanism of RUNX1 in regulating keratinocyte proliferation and migration remains unclear. Cell counting kit-8 and wound-healing assays were implemented for examining keratinocyte viability and migration, respectively. Western blotting and real-time quantitative polymerase chain reaction were utilized for quantifying protein and RNA levels. Luciferase reporter assay was employed for verifying the interaction between RUNX1, miR-17-5p, and long noncoding RNA H19. The results showed that RUNX1 depletion promoted keratinocyte proliferation and migration and repressed extracellular matrix degradation. Mechanistically, H19 upregulated RUNX1 expression by competitively absorbing miR-17-5p. Rescue experiments revealed that overexpressing RUNX1 reversed H19 silencing-mediated effects on the phenotypes of keratinocytes. In conclusion, H19 knockdown promotes keratinocyte proliferation and migration and suppresses extracellular matrix degradation via the miR-17-5p/RUNX1 axis.

Proteinase K/Retinoic Acid-Loaded Cationic Liposomes as Multifunctional Anti-Acne Therapy to Disorganize Biofilm and Regulate Keratinocyte Proliferation.

Simultaneous anti-Cutibacterium acnes and anti-inflammatory actions are highly beneficial in treating acne vulgaris. In this study, we present novel anti-acne nanovesicles based on liposomes loaded with proteinase K (PK), retinoic acid (RA), and soyaethyl morpholinium ethosulfate (SME) to achieve an effective and safe treatment. This study examined in vitro planktonic and biofilm C. acnes elimination, as well as the keratinocyte proliferation suppression by liposomes. The multifunctional liposomes for treating C. acnes in mice were also evaluated. We acquired multifunctional liposomes with a size of 71 nm and zeta potential of 31 mV. The antimicrobial activity of SME was enhanced after liposomal encapsulation according to the reduction of minimum bactericidal concentration (MBC) by 6-fold. The multifunctional liposomes exhibited a synergistically inhibitory effect on biofilm C. acnes colonization compared with the liposomes containing PK or those containing SME individually. The adhesive bacterial colony in the microplate was lessened by 62% after multifunctional liposome intervention. All liposomal formulations tested here demonstrated no cytotoxicity against the normal keratinocytes but inhibited C. acnes-stimulated cell hyperproliferation. The in vitro scratch assay indicated that the liposomal RA-but not free RA-restrained keratinocyte migration. The animal study showed that free RA combined with SME and multifunctional nanovesicles had a similar effect on diminishing C. acnes colonies in the skin. On the other hand, liposomes exhibited superior performance in recovering the impaired skin barrier function than the free control. We also found that RA-loaded nanovesicles had greater skin tolerability than free RA. The cationic liposomes containing dual PK and RA represented a potential treatment to arrest bacterial infection and associated inflammation in acne.

Defective cathepsin Z affects EGFR expression and causes autosomal dominant palmoplantar keratoderma.

The abnormal function of epidermal growth factor receptor (EGFR) has recently been shown to underlie various disorders of cornification. To delineate the genetic basis of a novel dominant form of palmoplantar keratoderma (PPK). Whole-exome (WES) and direct sequencing, quantitative real-time polymerase chain reaction, protein modelling, confocal immunofluorescence microscopy, immunoblotting, three-dimensional skin equivalents and an enzyme activity assay were used to delineate the genetic basis of a novel dominant form of PPK. WES revealed heterozygous variants (c.274T > C and c.305C > T) in CTSZ (encoding cathepsin Z) in four individuals (belonging to three unrelated families) with focal PPK. Bioinformatics and protein modelling predicted the variants to be pathogenic. Previous studies have suggested that EGFR expression may be subject to cathepsin regulation. Immunofluorescence revealed reduced cathepsin Z expression in the upper epidermal layers and concomitant increased epidermal EGFR expression in patients harbouring CTSZ variants. Accordingly, human keratinocytes transfected with constructs expressing PPK-causing variants in CTSZ displayed reduced cathepsin Z enzymatic activity, as well as increased EGFR expression. In line with the role played by EGFR in the regulation of keratinocyte proliferation, human keratinocytes transfected with the PPK-causing variants showed significantly increased proliferation that was abolished upon exposure to erlotinib, an EGFR inhibitor. Similarly, downregulation of CTSZ resulted in increased EGFR expression and increased proliferation in human keratinocytes, suggestive of a loss-of-function effect of the pathogenic variants. Finally, three-dimensional organotypic skin equivalents grown from CTSZ-downregulated cells showed increased epidermal thickness and EGFR expression as seen in patient skin; here, too, erlotinib was found to rescue the abnormal phenotype. Taken collectively, these observations attribute to cathepsin Z a hitherto unrecognized function in epidermal differentiation.

230 Investigating the role of histone deacetylases in human epidermis

Histone deacetylases (HDACs) remove acetyl moieties from lysine residues of histones and other proteins to induce epigenetic change to DNA, and hence are important regulators of gene expression. Within the skin, they play a role in regulating keratinocyte proliferation and differentiation. To date, four classes of the HDACs have been identified: Class I (HDAC1, HDAC2, HDAC3, and HDAC8), class II HDACs (HDAC4, HDAC5, HDAC6, HDAC7, HDAC9, and HDAC10), class III (SIRT1-7) and class IV (HDAC11) but their role in keratinocyte biology is largely unknown.

Transcription Factors Runx1 and Runx3 Suppress Keratin Expression in Undifferentiated Keratinocytes.

The Runt-related transcription factor (Runx) family has been suggested to play roles in stem cell regulation, tissue development, and oncogenesis in various tissues/organs. In this study, we investigated the possible functions of Runx1 and Runx3 in keratinocyte differentiation. Both Runx1 and Runx3 proteins were detected in primary cultures of mouse keratinocytes. Proteins were localized in the nuclei of undifferentiated keratinocytes but translocated to the cytoplasm of differentiated cells. The siRNA-mediated inhibition of Runx1 and Runx3 expression increased expression of keratin 1 and keratin 10, which are early differentiation markers of keratinocytes. In contrast, overexpression of Runx1 and Runx3 suppressed keratin 1 and keratin 10 expression. Endogenous Runx1 and Runx3 proteins were associated with the promoter sequences of keratin 1 and keratin 10 genes in undifferentiated but not differentiated keratinocytes. In mouse skin, the inhibition of Runx1 and Runx3 expression by keratinocyte-specific gene targeting increased the ratios of keratin 1- and keratin 10-positive cells in the basal layer of the epidermis. On the other hand, inhibition of Runx1 and Runx3 expression did not alter the proliferation capacity of cultured or epidermal keratinocytes. These results suggest that Runx1 and Runx3 likely function to directly inhibit differentiation-induced expression of keratin 1 and keratin 10 genes but are not involved in the regulation of keratinocyte proliferation.

733 G-protein-coupled receptors (GPCRs) in the regulation of keratinocyte proliferation and differentiation

G-protein-coupled receptors (GPCRs) and their associated heterotrimeric G protein-signaling cascades regulate epidermal stem cell fate. We have previously demonstrated that G-alpha stimulating (Gs) and inhibitory (Gi) proteins regulate downstream cAMP signaling which controls keratinocyte differentiation and proliferation in vitro and in vivo. In particular, Gs inactivation causes an expansion of the stem cell compartment resulting in basal cell carcinoma formation. On the other hand, decreasing cAMP signaling by Gi activation leads to epidermal hyperplasia and unbalanced keratinocyte proliferation and differentiation.

Long-Acting β2 Adrenergic Receptor Agonist Ameliorates Imiquimod-Induced Psoriasis-Like Skin Lesion by Regulating Keratinocyte Proliferation and Apoptosis.

Psoriasis is a chronic inflammatory disease that affects approximately 1%–5% of the population worldwide. Considering frequent relapse, adverse drug reactions, and large costs of treatment, it is urgent to identify new medications for psoriasis. Keratinocytes play an essential role during psoriasis development, and they express high levels of β2-Adrenergic receptor (β2-AR), which increases intracellular cAMP levels when activated. Increased level of cAMP is associated with the inhibition of epidermal cell proliferation. In the present study, we observed the effect of salmeterol, a long-acting β2-AR agonist, on the proliferation and apoptosis of keratinocytes as well as imiquimod-induced psoriasis-like skin lesions in mice. As phosphodiesterase 4 (PDE4) inhibitors increases intracellular cAMP concentration by inhibiting its inactivation, we further explored the synergetic effect of a PDE4 inhibitor and salmeterol on psoriasis-like skin lesions in mice. Our results indicated that salmeterol effectively inhibited the proliferation of HaCaT cells induced by TNF-α and serum, and this effect was accompanied by significantly increased apoptosis and CREB phosphorylation, which were reversed by the PKA inhibitor, H89. Salmeterol ameliorated imiquimod-induced psoriasis-like skin lesions in mice, but salmeterol combined with a PDE4 inhibitor had no synergetic effect in improving skin lesions in mice. Of note, the synergistic effects of anti-proliferation and induction of apoptosis in HaCaT cells appeared by inhibiting ERK signaling. In summary, salmeterol, a long-acting β2-AR agonist, alleviates the severity of psoriasis via inhibiting the proliferation and promoting apoptosis of keratinocytes, partially by activating the cAMP/PKA signaling pathway.

CircOAS3 Regulates Keratinocyte Proliferation and Psoriatic Inflammation by Interacting with Hsc70 via the JNK/STAT3/NF-κB Signaling Pathway.

Psoriasis is a chronic inflammatory disease of the skin with a very complex pathogenesis. Circular RNAs (circRNAs) play important regulatory roles in many diseases, including psoriasis. In this study, we found that circOAS3 expression was significantly upregulated in both psoriatic tissues and M5-induced keratinocytes. Silencing circOAS3 in HaCaT and Ker-CT cells inhibited their viability, promoted apoptosis, and blocked the cell cycle from the G1 to the S phase. RNA pull-down and RNA immunoprecipitation (RIP) analyses led to the identification of a direct interaction between circOAS3 and heat shock cognate protein 70 (Hsc70). Silencing circOAS3 expression negatively influenced Hsc70 protein expression but not mRNA expression. circOAS3 knockdown suppressed the activation of the JNK/STAT3/NF-κB signaling pathway. circOAS3 or Hsc70 silencing led to downregulated protein IL-6 expression, thus reducing psoriatic inflammation in vitro. In conclusion, the interaction between circOAS3 and Hsc70 mediates the proliferation and psoriatic inflammation of HaCaT and Ker-CT cells through the JNK/STAT3/NF-κB signaling pathway, suggesting that circOAS3 or Hsc70 may be a promising therapeutic target for psoriasis.

LncRNA XIST Engages in Psoriasis via Sponging miR-338-5p to Regulate Keratinocyte Proliferation and Inflammation

Introduction: Psoriasis is an immune-mediated polygenic inflammatory skin disease in which keratinocyte proliferation is an important mechanism. The study investigated the role and regulatory relationship between lncRNA XIST and miR-338-5p in psoriatic patients and cell models. Methods: Serum samples were collected from 55 psoriasis patients. HaCaT was recruited for the cell experiments, and induced by M5 cytokines to mimic psoriasis in vitro. XIST and miR-338-5p levels were detected via qRT-PCR. Cell viability under different treatments was evaluated using CCK-8. ELISA was applied to measure the concentration of inflammatory cytokines. The regulatory relationship was confirmed using luciferase reporter gene assay. Results: Serum XIST was elevated in patients with psoriasis and can distinguish the psoriasis patients from healthy controls according to the receiver operating characteristic curve. A high level of XIST was positively correlated with the PASI score and serum tumor necrosis factor-alpha (TNF-α), interleukin-17A [IL-17A], and IL-22 concentrations in psoriasis patients. XIST silencing suppressed M5-induced keratinocyte proliferation and restrained the discharge of inflammatory cytokines (TNF-α, IL-17A, IL-22) and chemokines (CXCL1, CXCL8, CCL20). XIST can sponge miR-338-5p, and miR-338-5p downregulation abolished the inhibitory effect of XIST silencing on cell proliferation and inflammation. miR-338-5p was highly expressed in the clinical serum samples from psoriasis patients. The target relationship between miR-338-5p and IL-6 was proved. Conclusion: LncRNA XIST is highly expressed in the serum of patients with psoriasis, and was positively correlated with disease severity and inflammation. XIST may regulate keratinocyte proliferation and inflammation via regulating miR-338-5p/IL-6 axis.

MicroRNA-17-3p is upregulated in psoriasis and regulates keratinocyte hyperproliferation and pro-inflammatory cytokine secretion by targeting CTR9.

Psoriasis is a chronic inflammatory skin disease. Although miRNAs are reported to be associated with the pathogenesis of psoriasis, the contribution of individual microRNAs toward psoriasis remains unclear. The miR-17-92 cluster regulates cell growth and immune functions that are associated with psoriasis. miR-17-3p is a member of miR-17-92 cluster; however, its role in dermatological diseases remains unclear. Our study aims at investigating the effects of miR-17-3p and its potential target gene on keratinocytes proliferation and secretion of pro-inflammatory cytokine and their involvement in psoriasis. Initially, we found that miR-17-3p was upregulated in psoriatic skin lesions, and bioinformatic analyses suggested that CTR9 is likely to be a target gene of miR-17-3p. Quantitative reverse-transcriptase PCR and immunohistochemical analysis revealed that CTR9 expression was downregulated in psoriatic lesions. Using dual-luciferase reporter assays, we identified CTR9 as a direct target of miR-17-3p. Further functional experiments demonstrated that miR-17-3p promoted the proliferation and pro-inflammatory cytokine secretion of keratinocytes, whereas CTR9 exerted the opposite effects. Gain-of-function studies confirmed that CTR9 suppression partially accounted for the effects of miR- 17-3p in keratinocytes. Furthermore, Western blot revealed that miR-17-3p activates the downstream STAT3 signaling pathway while CTR9 inactivates the STAT3 signaling pathway. Together, these findings indicate that miR-17-3p regulates keratinocyte proliferation and pro-inflammatory cytokine secretion partially by targeting the CTR9, which inactivates the downstream STAT3 protein, implying that miR-17-3p might be a novel therapeutic target for psoriasis.

MiR-21-3p regulates keratinocyte proliferation and apoptosis possibly via regulating Janus kinase/signal transducer and activator of transcription-3 pathway and cytokeratin 17 expression

Objectives We investigated the effect and mechanism of miR-21-3p on the biological behavior of keratinocyte HaCaT cells. Methods HaCaT cells were transfected with miR-21-3p mimics and miR-21-3p inhibitor, respectively. Cell proliferation was detected by CCK-8, and apoptosis and cell cycle were analyzed by flow cytometry. The expression changes of Bax and Bcl-2 were measured with immunohistochemistry. The mRNA expressions of IL-17A and STAT3 were detected by real-time fluorescence quantitative PCR. Cytokeratin 17 protein was detected by Western blot. The relationship between miR-21-3p and STAT3 was verified by dual luciferase reporter gene assay. Results The miR-21-3p mimics significantly promoted the proliferation and cell cycle progression of HaCaT cells. However, miR-21-3p mimics significantly inhibited cell apoptosis, decreased Bax expression and increased Bcl-2 expression. Additionally, miR-21-3p mimics significantly increased the expressions of Cytokeratin 17 protein, IL-17A mRNA and STAT3 mRNA. Of note, the miR-21-3p inhibitor exhibited contrary effects to miR-21-3p mimics. Furthermore, STAT3 was a direct target of miR-21-3p. Conclusion miR-21-3p may promote the abnormal proliferation and inhibit apoptosis of HaCaT cells, possibly through regulating JAK/STAT pathway and the expression of Cytokeratin 17.

Urea in Dermatology: A Review of its Emollient, Moisturizing, Keratolytic, Skin Barrier Enhancing and Antimicrobial Properties.

Urea is a hygroscopic molecule (capable of absorbing water) present in the epidermis as a component of the natural moisturizing factor (NMF) and is essential for the adequate hydration and integrity of the stratum corneum. Urea improves skin barrier function including antimicrobial defense by regulating gene expression in keratinocytes relevant for their differentiation and antimicrobial peptide production. It also plays a fundamental role in regulating keratinocyte proliferation. One of the first uses of urea in modern medicine was the topical treatment of wounds due to its proteolytic and antibacterial properties. At present, urea is widely used in dermatology to improve skin barrier function and as one of the most common moisturizers and keratolytic agents. Urea-containing formulations are available in diverse formulations and concentrations. Multiple clinical trials on the use of urea-containing formulations have shown significant clinical improvement in many of the dermatosis presenting with scaly and dry skin such as atopic dermatitis, ichthyosis, xerosis, seborrheic dermatitis and psoriasis, among others. Furthermore, urea can increase skin penetration and optimize the action of topical drugs. Urea-based products are well tolerated; their side effects are mild and are more frequent at high concentration. Here, we present a review of the use of urea in dermatology, discussing its mechanism of action, safety profile and frequent indications.

100 Activation of A2B adenosine receptor normalizes filaggrin and caspase-14 levels in a murine model of epidermal hyperplasia

A2B adenosine receptor (AR) is the subtype mainly expressed within the epidermis, regulating keratinocyte proliferation and inflammatory responses. In the murine model of epidermal hyperplasia induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), we recently demonstrated the protective role of A2B AR activation, reducing macroscopic and microscopic lesions and restoring the epidermal barrier. Caspase-14 is a crucial protease in the activation and catabolism of filaggrin, a protein with a pivotal role in the development of the cornified envelope.