An update on the role of long non-coding RNAs in psoriasis

The Role of Long Non-Coding RNA in the Pathogenesis of Psoriasis

Psoriasis is a chronic immune-mediated disease with complex pathogenesis. The altered proliferation and differentiation of keratinocytes, together with the activity of dendritic cells and T cells, are crucial drivers of psoriasis progression. Long non-coding RNAs (lncRNAs) are composed of over 200 nucleotides and exert a large variety of functions, including the regulation of gene expression. Under pathological conditions, the expression of lncRNAs is frequently dysregulated. Recent studies demonstrated that lncRNAs significantly affect major cellular processes, and their aberrant expression is likely involved in the pathogenesis of various disorders. In this review, we will discuss the role of lncRNAs in the pathophysiology of psoriasis. We will summarize recent studies that investigated the relationships between lncRNAs and keratinocyte proliferation and pro-inflammatory responses.

Inflammatory memory in psoriasis: From remission to recurrence

The routine use of targeted systemic immunomodulatory therapies has transformed outcomes for people with severe psoriasis, with skin clearance (clinical remission) rates up to 60% at 1 year of biologic treatment. However, psoriasis may recur following drug withdrawal, and as a result, patients tend to continue receiving costly treatment indefinitely. Here, we review research into the "inflammatory memory" in resolved psoriasis skin and the potential mechanisms leading to psoriasis recurrence following drug withdrawal. Research has implicated immune cells such as tissue resident memory T cells, Langerhans cells, and dermal dendritic cells, and there is growing interest in keratinocytes and fibroblasts. A better understanding of the interactions between these cell populations, enabled by single cell technologies, will help to elucidate the events underpinning the shift from remission to recurrence. This may inform the development of personalized strategies for sustaining remission while reducing long-term drug burden.

Formononetin attenuates psoriasiform inflammation by regulating interferon signaling pathway

BACKGROUND

Psoriasis is a long-lasting, inflammatory, continuous illness caused through T cells and characterized mainly by abnormal growth and division of keratinocytes. Currently, corticosteroids are the preferred option. However, prolonged use of traditional topical medication can lead to adverse reactions and relapse, presenting a significant therapeutic obstacle. Improved alternative treatment options are urgently required. Formononetin (FMN) is a representative component of isoflavones in Huangqi (HQ) [Astragalus membranaceus (Fisch.) Bge.]. It possesses properties that reduce inflammation, combat oxidation, inhibit tumor growth, and mimic estrogen. Although FMN has been shown to ameliorate skin barrier devastation via regulating keratinocyte apoptosis and proliferation, there are no reports of its effectiveness in treating psoriasis.

OBJECTIVE

Through transcriptomics clues and experimental investigation, we aimed to elucidate the fundamental mechanisms underlying FMN's action on psoriasis.

MATERIALS AND METHODS

Cell viability was examined using CCK8 assay in this study. The results of analysis of differentially expressed genes (DEGs) between FMN-treated HaCaT cells and normal HaCaT cells using RNA-sequencing (RNA-seq) were presented on volcano plots and heatmap. Enrichment analysis was conducted on DEGs using Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO), and results were validated through RT-qPCR verification. After 12 days of FMN treatment in psoriasis mouse model, we gauged the PASI score and epidermis thickness. A variety of techniques were used to assess FMN's effectiveness on inhibiting inflammation and proliferation related to psoriasis, including RT-qPCR, HE staining, western blot, and immunohistochemistry (IHC).

RESULTS

The findings indicated that FMN could suppress the growth of HaCaT cells using CCK8 assay (with IC50 = 40.64 uM) and 20 uM FMN could reduce the level of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) to the greatest extent. FMN-treated HaCaT cells exhibited 985 up-regulated and 855 down-regulated DEGs compared to normal HaCaT cells. GO analysis revealed that DEGs were linked to interferon (IFN) signaling pathway. Furthermore, FMN improved pathological features, which encompassed decreased erythema, scale, and thickness scores of skin lesions in psoriasis mouse model. In vivo experiments confirmed that FMN down-regulated expression of IFN-α, IFN-β, IFN-γ, decreased secretion of TNF-α and IL-17 inflammatory factors, inhibited expression of IFN-related chemokines included Cxcl9, Cxcl10, Cxcl11 and Cxcr3 and reduced expression of transcription factors p-STAT1, p-STAT3 and IFN regulatory factor 1 (IRF1) in the imiquimod (IMQ) group.

CONCLUSIONS

In summary, these results suggested that FMN played an anti-inflammatory and anti-proliferative role in alleviating psoriasis by inhibiting IFN signaling pathway, and FMN could be used as a potential therapeutic agent.

LncRNA MIR181A2HG negatively regulates human keratinocytes proliferation by binding SRSF1

Psoriasis is a common chronic inflammatory skin disease. Abnormal proliferation of keratinocytes plays an important role in the pathogenesis of psoriasis. Long non-coding RNAs (lncRNAs) are involved in the regulation of a variety of cell biological processes. The purpose of this study was to investigate the potential role of lncRNA MIR181A2HG in the proliferation of human keratinocytes. qRT-PCR and Western blotting were performed to measure the expression levels of MIR181A2HG, SRSF1, KRT6, and KRT16 in tissue specimens and HaCaT keratinocytes. The effects of MIR181A2HG on HaCaT keratinocytes proliferation were evaluated using Cell Counting Kit-8 (CCK-8) assays, 5-Ethynyl-2'-deoxyuridine (EdU) incorporation, and cell-cycle assays. RNA pulldown-mass spectrometry (MS) was applied to identify the proteins interacting with MIR181A2HG. RNA pull-down-Western blotting and RNA immunoprecipitation coupled with real-time quantitative reverse transcription-PCR (RIP-qRT-PCR) assays were used to determine the interactions between MIR181A2HG and its RNA-binding proteins (RBPs). MIR181A2HG was down-regulated in psoriasis tissues. MIR181A2HG overexpression induced G0/G1 and G2/M phase cell cycle arrest and decreased the protein levels of KRT6, KRT16, Cyclin D1, CDK4, and Cyclin A2 in HaCaT keratinocytes. MIR181A2HG knockdown showed the opposite effect. By using RNA pulldown-MS, 356 proteins were identified to interact with MIR181A2HG potentially. Bioinformatics analysis showed that NOP56 and SRSF1 may be RNA binding proteins (RBPs) that may be interact with MIR181A2HG. Furthermore, by using RNA pull-down-Western blotting and RIP-qRT-PCR, SRSF1 was determined to interact with MIR181A2HG. Moreover, silencing of SRSF1 inhibited keratinocytes proliferation, which could be reversed with the knockdown of MIR181A2HG. Our findings indicated that MIR181A2HG can negatively regulate HaCaT keratinocytes proliferation by binding SRSF1, suggesting that MIR181A2HG and SRSF1 may serve as potential targets for the treatment of psoriasis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-024-00621-6.

Involvement of transcribed lncRNA uc.291 in hyperproliferative skin disorders

The uc.291 transcript controls keratinocytes differentiation by physical interaction with ACTL6A and subsequent induction of transcription of the genes belonging to the epidermal differentiation complex (EDC). Uc.291 is also implicated in the dedifferentiation phenotype seen in poorly differentiated cutaneous squamous cell carcinomas. Here, we would like to investigate the contribution of uc.291 to the unbalanced differentiation state of keratinocytes observed in hyperproliferative skin disorders, e. g., psoriasis. Psoriasis is a multifactorial inflammatory disease, caused by alteration of keratinocytes homeostasis. The imbalanced differentiation state, triggered by the infiltration of immune cells, represents one of the events responsible for this pathology. In the present work, we explore the role of uc.291 and its interactor ACTL6A in psoriasis skin, using quantitative real-time PCR (RT-qPCR), immunohistochemistry and bioinformatic analysis of publicly available datasets. Our data suggest that the expression of the uc.291 and of EDC genes loricrin and filaggrin (LOR, FLG) is reduced in lesional skin compared to nonlesional skin of psoriatic patients; conversely, the mRNA and protein level of ACTL6A are up-regulated. Furthermore, we provide evidence that the expression of uc.291, FLG and LOR is reduced, while ACTL6A mRNA is up-regulated, in an in vitro psoriasis-like model obtained by treating differentiated keratinocytes with interleukin 22 (IL-22). Furthermore, analysis of a publicly available dataset of human epidermal keratinocytes treated with IL-22 (GSE7216) confirmed our in vitro results. Taken together, our data reveal a novel role of uc.291 and its functional axis with ACTL6A in psoriasis disorder and a proof of concept that biological inhibition of this molecular axis could have a potential pharmacological effect against psoriasis and, in general, in skin diseases with a suppressed differentiation programme.

Genome-Wide Differential Transcription of Long Noncoding RNAs in Psoriatic Skin

Long noncoding RNAs (lncRNAs) may contribute to the formation of psoriatic lesions. The present study's objective was to identify long lncRNA genes that are differentially expressed in patient samples of psoriasis through computational analysis techniques. By using previously published RNA sequencing data from psoriatic and healthy patients (n = 324), we analysed the differential expression of lncRNAs to determine transcripts of heightened expression. We computationally screened lncRNA transcripts as annotated by GENCODE across the human genome and compared transcription in psoriatic and healthy samples from two separate studies. We observed 54 differentially expressed genes as seen in two independent datasets collected from psoriasis and healthy patients. We also identified the differential expression of LINC01215 and LINC1206 associated with the cell cycle pathway and psoriasis pathogenesis. SH3PXD2A-AS1 was identified as a participant in the STAT3/SH3PXD2A-AS1/miR-125b/STAT3 positive feedback loop. Both the SH3PXD2A-AS1 and CERNA2 genes have already been recognised as part of the IFN-γ signalling pathway regulation. Additionally, EPHA1-AS1, CYP4Z2P and SNHG12 gene upregulation have all been previously linked to inflammatory skin diseases. Differential expression of various lncRNAs affects the pathogenesis of psoriasis. Further characterisation of lncRNAs and their functions are important for developing our understanding of psoriasis.

The role of glucose-dependent insulinotropic polypeptide 3 (G1P-3) and nucleolar phosphoprotein-1 (NPM1) in pathogenesis of psoriasis

Background Psoriasis is a multifactorial, hyperproliferative, chronic inflammatory skin disease affecting males and females equally. Aims To study the expression of certain non-coding RNAs, Interferon Alpha Inducible Protein 6 (IFI6), previously named Glucose-dependent Insulinotropic Polypeptide 3 (G1P-3), and nucleolar phosphoprotein (in serum and tissue), and to attempt to elucidate their role in the pathogenesis of psoriasis, which in turn might help in treatment. Methods Twenty patients with psoriasis and 20 healthy subjects were included in this study. Serum and skin biopsies were obtained from all participants. Molecular biology techniques were employed to estimate the expression levels of long noncoding G1P-3 and nucleolar phosphoprotein in serum and skin biopsy. Results Psoriasis patients had a mean age of 41.85 ± 12.29. The median serum G1P-3 level of the patients' group (3.330) was significantly higher than that of the control group (1.085) (P ≤ 0.001). Tissue G1P-3 level of the patients' group (6.495) was also significantly higher compared to that of controls (1.040) (P ≤ 0.001). Similarly, for nucleolar phosphoprotein, the median serum level of patients' group (2.030) was significantly higher than that of controls (1.040) (P ≤ 0.001) and median tissue level (5.425) was also significantly higher than that of controls (1.040) (P ≤ 0.001). Limitations In this study, only outpatients were included and follow-up was not well-handled. For future work, follow-up can be considered. Conclusion Long non-coding G1P-3 as well as nucleolar phosphoprotein may be considered as genetic markers for psoriasis susceptibility. In future, these might provide a novel direction for advances in psoriasis treatment.

lncRNA TUG1 regulates Smac/DIABLO expression by competitively inhibiting miR-29b and modulates the apoptosis of lens epithelial cells in age-related cataracts

BACKGROUND

As one of the early discovered long non-coding RNAs (lncRNA), taurine upregulation gene 1 ( TUG1 ) has been widely expressed in a variety of tumors. Moreover, it promotes cell proliferation, differentiation, apoptosis, and migration. However, our understanding of its importance in the pathogenesis of cataracts remains limited. This study aimed to explore the mechanism by which lncRNA TUG1 mediates lens epithelial cell apoptosis in age-related cataracts (ARC) by regulating the microRNAs (miR-29b)/second mitochondria-derived activator of caspases axis, and to identify more non-surgical strategies for cataract treatment.

METHODS

The messenger RNA expression levels of TUG1 , miR-29b, and Smac were detected using quantitative real-time polymerase chain reaction in vivo and in vitro . The expression of the Smac protein was analyzed by Western blotting and immunofluorescence. Flow cytometry and cell counting kit-8 assays were used to detect the cell apoptosis and proliferation rates, respectively. The targeted regulatory relationship between lncRNA TUG1 , miR-29b, and Smac was verified by viral vector construction, co-transfection, nuclear and cytoplasmic separation, luciferase reporter assays, and RNA immunoprecipitation.

RESULTS

TUG1 and Smac were expressed at high levels in ARC and HLE-B3 cells treated with 200 μmol/L H 2 O 2 , whereas miR-29b expression was decreased. In vitro cell experiments confirmed that down-regulation of TUG1 could inhibit the apoptosis of lens epithelial cells. Mechanistically, Smac expression was negatively regulated by miR-29b. TUG1 competitively inhibited miR-29b expression and caused greater release of Smac. In addition, miR-29b partially reversed the effects of TUG1 on human lens epithelial cell line cells.

CONCLUSIONS

lncRNA TUG1 increases Smac expression and promotes apoptosis of lens epithelial cells in ARC by competitively inhibiting miR-29b. This mechanism is the cytological basis for ARC formation. Based on these results, the lncRNA TUG1/miR29b/Smac axis may be a new molecular pathway that regulates ARC development.

Integrative single-cell transcriptomic investigation unveils long non-coding RNAs associated with localized cellular inflammation in psoriasis

Psoriasis is a complex, chronic autoimmune disorder predominantly affecting the skin. Accumulating evidence underscores the critical role of localized cellular inflammation in the development and persistence of psoriatic skin lesions, involving cell types such as keratinocytes, mesenchymal cells, and Schwann cells. However, the underlying mechanisms remain largely unexplored. Long non-coding RNAs (lncRNAs), known to regulate gene expression across various cellular processes, have been particularly implicated in immune regulation. We utilized our neural-network learning pipeline to integrate 106,675 cells from healthy human skin and 79,887 cells from psoriatic human skin. This formed the most extensive cell transcriptomic atlas of human psoriatic skin to date. The robustness of our reclassified cell-types, representing full-layer zonation in human skin, was affirmed through neural-network learning-based cross-validation. We then developed a publicly available website to present this integrated dataset. We carried out analysis for differentially expressed lncRNAs, co-regulated gene patterns, and GO-bioprocess enrichment, enabling us to pinpoint lncRNAs that modulate localized cellular inflammation in psoriasis at the single-cell level. Subsequent experimental validation with skin cell lines and primary cells from psoriatic skin confirmed these lncRNAs' functional role in localized cellular inflammation. Our study provides a comprehensive cell transcriptomic atlas of full-layer human skin in both healthy and psoriatic conditions, unveiling a new regulatory mechanism that governs localized cellular inflammation in psoriasis and highlights the therapeutic potential of lncRNAs in this disease's management.

Long noncoding RNA (taurine upregulated gene 1) and micro RNA-377: emerging players in the development of metabolic syndrome among psoriasis patients

Background

Psoriasis (PsO) is an immune-mediated dermatosis and systemic inflammatory condition that can affect the skin, joints, and other organs and tissues with a range of comorbidities. The activation of proinflammatory cytokines is the primary cause of the development of skin lesions in PsO. Patients with PsO have a higher risk of developing cardiovascular metabolic comorbidities; among these is the metabolic syndrome (MetS). Particularly, MetS is characterized by abdominal obesity, hypertension, hyperglycemia, and hyperlipidemia, has been linked to PsO. The connection between PsO and MetS is believed to be caused by PsO generating systemic inflammation, which then results in elevated inflammatory adipokines, endothelial dysfunction, and insulin resistance. Micro RNA-377 and long noncoding RNA taurine upregulated 1 (TUG1) are both involved in the control of a variety of inflammatory disorders in humans and can be employed as biomarkers for the diagnosis and prognosis of psoriasis. The aim of the present study is to establish a panel of biomarkers for the early diagnosis of MetS incidence in psoriasis and thereby, reducing its lethal consequences.

Results

In this study, 120 patients: 40 psoriatic patients, 40 psoriatic patients with metabolic syndrome, and 40 healthy subjects were conducted. Expressions of Long noncoding RNA Taurine Upregulated Gene-1 (TUG1), miRNA-377 and Peroxisome Proliferator-Activated Receptor-γ (PPAR-γ) were assessed in tissue lesion by real-time PCR. ELISA technique was carried out for the detection of serum levels of plasminogen activator inhibitor-1 (PAI-1) and transforming growth factor β (TGFβ). Moreover, miRNA-377 expression was significantly elevated with the simultaneous down-regulation of both TUG-1 and PPAR-γ in PsO-MetS group when compared to those of PsO and control groups. Furthermore, PAI-1 and TGFβ levels were higher in PsO-MetS than PsO.

Conclusions

The dysregulated levels of TUG-1, miRNA-377, PPAR-γ, PAI-1, and TGFβ, biomarkers may provide information about their potential role in the emergence of MetS in psoriasis patients.

Pathogenesis of psoriasis via miR-149-5p/AKT1axis by long noncoding RNA BLACAT1

BACKGROUND

Psoriasis is a chronic, complicated, and recurrent inflammatory skin disease, whose precise molecular mechanisms need to be further explored. The lncRNA bladder cancer-associated transcript 1 (BLACAT1) is aberrantly expressed in many cancers and associated with cellular hyperproliferation and may play a role in the pathogenesis of psoriasis. Thus, this study aimed at identifying the primary mechanism associated with BLACAT1 in psoriasis pathogenesis.

MATERIALS AND METHODS

Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was performed to detect the expression of BLACAT1 in psoriasis tissues. Cell proliferation and apoptosis were assessed using cell counting kit-8 and apoptosis assays, respectively. In vivo experiments and histopathological examinations were performed to investigate the effects of BLACAT1 on psoriasis. Dual-luciferase Reporter and RNA immunoprecipitation assays were used to evaluate the relationship among BLACAT1 and miR-149-5p and AKT1.

RESULTS

BLACAT1 was upregulated in psoriasis tissues. Overexpression exacerbated the clinical manifestation of psoriasis and increased the epidermal thickness in imiquimod-induced mice. BLACAT1 could promote proliferation and inhibit apoptosis of keratinocytes. Further studies demonstrated that BLACAT1 positively regulated AKT1 expression, functioning as a competing endogenous RNA (ceRNA) by sponging miR-149-5p.

CONCLUSIONS

The combination of lncRNA BLACAT1 and miR-149-5p regulates AKT1 expression and promotes psoriasis formation thus may provide a new direction for psoriasis treatment.

CircEIF5 contributes to hyperproliferation and inflammation of keratinocytes in psoriasis via p-NFκB and p-STAT3 signalling pathway

Psoriasis is a chronic, immune-mediated skin disease accompanied by hyperproliferation and inflammation of keratinocytes. Circular RNAs (circRNAs) as new players regulating the development of psoriasis have been reported in recent years. However, its mechanism has not yet been fully revealed. In this study, we identified that hsa_circ_0033469 (circEIF5) was highly expressed in psoriasis tissues compared with the normal skin. We investigated the functional roles of circEIF5 in proliferation and inflammatory of HaCat cells under M5-stimulated inflammatory condition. By using a approach of knockdown and overexpression of circEIF5, we showed that circEIF5 could promote proliferation by facilitating the G1/S transition and increase secretion of chemokines in HaCat cells. These moderating effects of circEIF5 were associated with the activating of the NF-κB and STAT3 signalling pathways. Moreover, NF-κB and STAT3 inhibition abrogated circEIF5-induced promotion of cell proliferation and chemokine secretion. These results indicated that through NF-κB and STAT3 signalling pathways, circEIF5 regulated the proliferation and chemokine secretion of HaCat cells and contributed to the pathogenesis of psoriasis, which might become a potent target for psoriasis treatment.

Recent Update on Immunopathogenesis of Psoriasis

Psoriasis is a chronic disabling complex inflammatory disorder prevalent worldwide with environmental and genetic components that involve predominantly skin in addition to nails and joints associated with various systemic comorbidities having periods of exacerbations and remissions. Psoriasis is characterized by hyper-proliferation as well as abnormal differentiation of epidermal keratinocytes and lymphocyte infiltration (mainly T cells) with resultant inflammatory cytokines and chemokines. Immunological and genetic studies over the last decade have identified genetic susceptibility risk alleles, molecular, cellular and immunological mechanisms involved in immunopathogenesis of psoriasis. The current disease model emphasizes the role of aberrant Th1 and Th17 responses regulated by a complex network of different cytokines, including TNF-α, IL-17 and IL-23; signal transduction pathways downstream to the cytokine receptors; and various activated transcription factors, including NF-κB, interferon regulatory factors and signal transducer and activator of transcriptions. Cytokines targeting biologics (IL-17, IL-23 and TNFα) therapies have revolutionized the management of severe skin disease having beneficial effects on joints and systemic inflammation of psoriasis as well. Further better understanding of immunopathogenesis of psoriasis will pave way for precision medicine based on specific immunopathogenic targets in a given phenotype of disease. Complex interplay of psoriasis with associated comorbidities is also a future area of research for overall better patient management and to improve their quality of life.