X-inactive Specific Transcript Research Articles

XIST and MUC1-C form an auto-regulatory pathway in driving cancer progression

The long non-coding RNA X-inactive specific transcript (lncRNA XIST) and MUC1 gene are dysregulated in chronic inflammation and cancer; however, there is no known interaction of their functions. The present studies demonstrate that MUC1-C regulates XIST lncRNA levels by suppressing the RBM15/B, WTAP and METTL3/14 components of the m6A methylation complex that associate with XIST A repeats. MUC1-C also suppresses the YTHDF2-CNOT1 deadenylase complex that recognizes m6A sites and contributes to XIST decay with increases in XIST stability and expression. In support of an auto-regulatory pathway, we show that XIST regulates MUC1-C expression by promoting NF-κB-mediated activation of the MUC1 gene. Of significance, MUC1-C and XIST regulate common genes associated with inflammation and stemness, including (i) miR-21 which is upregulated across pan-cancers, and (ii) TDP-43 which associates with the XIST E repeats. Our results further demonstrate that the MUC1-C/XIST pathway (i) is regulated by TDP-43, (ii) drives stemness-associated genes, and (iii) is necessary for self-renewal capacity. These findings indicate that the MUC1-C/XIST auto-regulatory axis is of importance in cancer progression.

Dysregulation of the Long Noncoding RNA X-Inactive–Specific Transcript Expression in Male Patients with Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a sex-biased disease with female gender as a significant risk factor. Recently, we reported that increased expression of the long non-coding (lnc)RNA Xist, as induced by an intersectin-1s protein fragment with proliferative potential (EHITSN), may explain the sexual dimorphism of female pulmonary artery endothelial cells (ECs) and at least in part, the imbalance sex/ratio of PAH.Xist is essential for X-chromosome inactivation and dosage compensation of X-linked genes. Increased Xist expression was also detected in a subset of ECs and lung tissue samples of male PAH patients. The role of different Xist expression levels in ECs of male PAH patients (ECPAH) was studied in several lines of male ECPAH in conjunction with molecular, biochemical, morphological, and functional approaches. Male ECPAH showed on average 10.3-fold increase in high Xist vs. low Xist, a significant association between Xist levels and their proliferative potential, and a heterogeneous methylation of the Xist/Tsix locus. Interestingly, Xist up-regulation in male ECPAH decreases the expression of Klf2, via EHITSN interaction with EZH2, the catalytic subunit of the polycomb repressive complex 2. Moreover, the studies demonstrate that EHITSN-triggered p38/Elk1/c-Fos signaling is a pathological mechanism central to ECPAH proliferation and the dynamic crosstalk with cell cycle regulatory proteins ccna1/ccnd2, and Xist-EZH2-Klf2 interaction participate directly and differentially in establishing the proliferative profile of male ECPAH.

Discovering therapeutic possibilities for polycystic ovary syndrome by targeting XIST and its associated ceRNA network through the analysis of transcriptome data

Long non-coding RNA (lncRNA) regulates many physiological processes by acting as competitive endogenous RNA (ceRNA). The dysregulation of lncRNA X-inactive specific transcript (XIST) has been shown in various human disorders. However, its role in the pathogenesis of polycystic ovary syndrome (PCOS) is yet to be explored. This study aimed to explore the underlying mechanism of XIST in the pathogenesis of PCOS, specifically through dataset functional analysis. GEO PCOS datasets including RNA-seq, microarray, and miRNA-seq in granulosa cells (GCs) and blood, were examined and comprehensively analyzed. Enrichment analysis, ROC curve constructions, lncRNA-miRNA-mRNA interaction network analyses, and qRT-PCR validation were performed followed by a series of drug signature screenings. Our results revealed significant dysregulation in the expression of 1131 mRNAs, 30 miRNAs, and XIST in GCs of PCOS patients compared to healthy individuals. Of the120 XIST-correlated upregulated genes, 25 were enriched in inflammation-related pathways. Additionally, 5 miRNAs were identified as negative regulators of XIST-correlated genes. Accordingly, a ceRNA network containing XIST-miRNAs-mRNAs interactions was constructed. Furthermore, 6 genes, including AQP9, ETS2, PLAU, PLEK, SOCS3, and TNFRSF1B served as both GCs and blood-based biomarkers. By analyzing the number of interactions among XIST, miRNAs, and mRNAs, we pinpointed ETS2 as the pivotal gene within the ceRNA network. Our findings reveal a novel XIST- hsa-miR-146a-5p, hsa-miR-144-3p, and hsa-miR-1271-5p-ETS2 axis that comprehensively elucidates the XIST-associated mechanism underlying PCOS onset. qRT-PCR analysis further confirmed the, overexpression of both XIST and ETS2 . Furthermore, our results demonstrated that XIST and ETS2 were correlated with some assisted reproductive technologies outcomes. Finally, we identified two novel compounds including, methotrexate/folate and threonine using drug–gene interaction databases for PCOS management. These findings provide novel insights into the molecular etiology, diagnosis, and potential therapeutic interventions for PCOS.

Inhibition of Mir-21-5p Affects the Expression of LNCRNA X-Inactive Specific Transcript and Induces Apoptosis in MCF-7 Breast Cancer Cells

Background: We aimed to investigate  miR-21-5p inhibition effect on lncRNA-XIST expression and apoptosis status of MCF-7 cells.
 Methods: The MCF-7 cells were cultured and transfected by the anti-miR-21-5p oligonucleotide and expression of miR-21-5p, lncRNA-XIST, apoptosis-associated genes (bax and p53) and one miR-21-5p-unrelated lncRNA (BC200) was assessed by RT-qPCR. Furthermore, cell viability checked by MTT assay and apoptosis and cell cycle in transfected cells were detected by flow cytometry. Also, bioinformatics analysis on the transcriptome data confirmed that the lncRNA XIST might have a critical role in breast cancer (BC) cell apoptosis through ceRNAs mechanism and possible regulatory interactions with miR-21-5p.
 Results: Expression of miR-21-5p and lncRNA-XIST was significantly down- and up-regulated respectively (P<0.05). However, there was no significant change in lncRNA-BC200 expression. Also, the expression of bax and p53 upraised significantly (P<0.05). In transfected cells, MTT and flow cytometry assays reported a highly significant decrease and increase in viability and apoptosis respectively.
 Conclusion: Inhibition of miR-21-5p resulted in significant upregulation of lncRNA-XIST and apoptosis-associated genes bax and p53, which led to the induction of apoptosis in MCF-7 cells. Therefore, more investigations may provide a valuable target for studies on molecular therapies for BC.    

Transcription suppression of GABARAP mediated by lncRNA XIST-EZH2 interaction triggers caspase-11-dependent inflammatory injury in ulcerative colitis

BackgroundWe have previously found that enhancer of zeste homolog 2 (EZH2) is correlated with inflammatory infiltration and mucosal cell injury in ulcerative colitis (UC). This study aims to analyze the role of X-inactive specific transcript (XIST), a possible interactive long non-coding RNA of EZH2, in UC and to explore the mechanisms. MethodsC57BL/6N mice were treated with dextran sulfate sodium (DSS), and mouse colonic mucosal epithelial cells were treated with DSS and lipopolysaccharide (LPS) for UC modeling. The UC-related symptoms in mice, and the viability and apoptosis of mucosal epithelial cells were determined. Inflammatory injury in animal and cellular models were assessed through the levels of ACS, occludin, IL-1β, IL-18, TNF-α, caspase-1, and caspase-11. Molecular interactions between XIST, EZH2, and GABA type A receptor-associated protein (GABARAP) were verified by immunoprecipitation assays, and their functions in inflammatory injury were determined by gain- or loss-of-function assays. ResultsXIST was highly expressed in DSS-treated mice and in DSS + LPS-treated mucosal epithelial cells. It recruited EZH2, which mediated gene silencing of GABARAP through H3K27me3 modification. Silencing of XIST alleviated body weight loss, colon shortening, and disease active index of mice and reduced inflammatory injuries in their colon tissues. Meanwhile, it reduced apoptosis and inflammation in mucosal epithelial cells. However, these alleviating effects were blocked by either EZH2 overexpression or GABARAP knockdown. Rescue experiments identified caspase-11 as a key effector mediating the inflammatory injury following GABARAP loss. ConclusionThis study suggests that the XIST-EZH2 interaction-mediated GABARAP inhibition activates caspase-11-dependent inflammatory injury in UC.

Long noncoding RNA XIST: A novel independent prognostic biomarker for patients with ABC-DLBCL receiving R-CHOP treatment.

Approximately one-third of activated B-cell-like diffuse large B-cell lymphoma (ABC-DLBCL) cases were unresponsive to standard first-line therapy; thus, identifying biomarkers to evaluate therapeutic efficacy and assessing the emergence of drug resistance is crucial. Through early-stage screening, long noncoding RNA (lncRNA) X-inactive specific transcript (XIST) was found to be correlated with the R-CHOP treatment response. This study aimed to clarify the characteristics of XIST in ABC-DLBCL. The expression level of XIST in 161 patients with ABC-DLBCL receiving R-CHOP therapy was examined via RNA in situ hybridization, and the association between XIST expression and clinicopathological features, treatment response, and prognosis was analyzed in the study cohort and validated in the Gene Expression Omnibus cohort. Cell biological experiments and bioinformatics analyses were conducted to reveal aberrant signaling. The proportion of complete response in patients with high XIST expression was lower than that in patients with low XIST expression (53.8% vs. 77.1%) (P = 0.002). High XIST expression was remarkably associated with the characteristics of tumor progression and was an independent prognostic element for overall survival (P = 0.039) and progression-free survival (P = 0.027) in ABC-DLBCL. XIST was proven to be involved in m6A-related methylation and ATF6-associated autophagy. XIST knockdown repressed ABC-DLBCL cellular proliferation by regulating Raf/MEK/ERK signaling. High XIST expression was associated with ABC-DLBCL tumorigenesis and development and contributed to R-CHOP treatment resistance. XIST may be a promising signal to predict ABC-DLBCL prognosis.

Long Non-coding RNA X-Inactive Specific Transcript Promotes Esophageal Squamous Cell Carcinoma Progression via the MicroRNA 34a/Zinc Finger E-box–Binding Homeobox 1 Pathway

BackgroundThe long non-coding RNA X-inactive specific transcript (XIST) plays a crucial role in transcriptional silencing of the X chromosome. Zinc finger E-box-binding homeobox 1 (ZEB1) is a transcription factor involved in epithelial-mesenchymal transition (EMT) regulation.AimsThis study aimed to investigate the impact of XIST on esophageal squamous cell carcinoma (ESCC) progression and its underlying mechanism involving the miR-34a/ZEB1/E-cadherin/EMT pathway.MethodsXIST and ZEB1 expression were analyzed using quantitative PCR and immunohistochemistry. XIST knockdown was achieved in KYSE150 ESCC cells using siRNA or shRNA lentivirus transfection. Proliferation, migration, and invasion abilities were assessed, and luciferase reporter assays were performed to confirm XIST-miR-34a-ZEB1 interactions. In vivo ESCC growth was evaluated using a xenograft mouse model.ResultsXIST and ZEB1 were upregulated in tumor tissues, correlating with metastasis and reduced survival. XIST knockdown inhibited proliferation, migration, and invasion of KYSE150 cells. It decreased ZEB1 expression, increased E-cadherin and miR-34a levels. Luciferase reporter assays confirmed miR-34a binding to XIST and ZEB1. XIST knockdown suppressed xenograft tumor growth.ConclusionXIST promotes ESCC progression via the miR-34a/ZEB1/E-cadherin/EMT pathway. Targeting the XIST/miR-34a/ZEB1 axis holds therapeutic potential and serves as a prognostic biomarker in ESCC.Graphical This study has discovered an XIST-associated pathway involved in the regulation of ZEB1 expression, thereby influencing the progression of squamous cell carcinoma (ESCC). The specific mechanism is as follows: XIST can regulates ZEB1 expression by sponging miR-34a, ultimately promoting the metastasis of tumor by down-regulating the expression of E-cadherin.

Long noncoding RNA XIST promotes cell proliferation and migration in diabetic foot ulcers through the miR-126-3p/EGFR axis

BackgroundThe prevalence of diabetic foot ulcers (DFUs) has caused serious harm to human health. To date, a highly effective treatment is lacking. Long noncoding RNA X-inactive specific transcript (lncRNA XIST) has been the subject of mounting research studies, all of which have found that it serves as a protective factor against certain diseases; however, its function in DFUs is not entirely understood. This study was performed to determine the importance of the lncRNA XIST in the pathogenesis and biological function of DFUs.MethodsDiabetic ulcer skin from rats was analysed using haematoxylin-eosin (HE), Masson’s trichrome, and immunohistochemistry (IHC) staining. The differences in the expression of genes and proteins were examined with real-time quantitative polymerase chain reaction (RT–qPCR) and Western blotting. Next, the interaction was verified with a dual luciferase gene reporter assay. In addition, CCK-8, Transwell, and wound healing assays were used to assess the proliferation and migration of HaCaT cells.ResultsThe lncRNA XIST and epidermal growth factor receptor (EGFR) were downregulated, while microRNA-126-3p (miR-126-3p) was increased in diabetic ulcer rat skin tissues and high glucose-induced HaCaT cells. In addition, we found that the lncRNA XIST binds to miR-126-3p and that EGFR is directly targeted by miR‑126‑3p. Silencing XIST contributed to upregulated miR-126-3p expression, thus lowering EGFR levels and inhibiting the proliferative and migratory abilities of high glucose-treated HaCaT cells; however, the miR-126-3p inhibitor and overexpression of EGFR reversed this effect.ConclusionDecreased lncRNA XIST expression inhibits the proliferative and migratory abilities of high glucose-induced HaCaT cells by modulating the miR-126-3p/EGFR axis, causing delayed wound healing.

Evaluation of tumor-educated platelet long non-coding RNAs (lncRNAs) as potential diagnostic biomarkers for colorectal cancer.

Cancer-derived circulating components are increasingly considered as candidate sources for non-invasive diagnostic biomarkers. This study aimed to investigate the expression of tumor-educated platelet (TEP) long non-coding RNAs (lncRNAs) in colorectal cancer (CRC) patients and determine whether it could be served as a potential tool for CRC diagnosis. Relative quantitative real-time PCR (qRT-PCR) was used to detect the expression levels of three cancer-related platelet-derived lncRNAs CCAT1, HOTTIP, and XIST in 75 CRC patients and 42 healthy controls. Quantitative data were analyzed by SPSS (IBM Corp., Armonk, NY, USA) for comparison of cancer and non-cancer individuals. The receiver operating characteristic (ROC) curve analysis was further performed to assess the diagnostic values of lncRNAs within the CRC patients. The expression levels of lncRNAs colon cancer associated transcript 1 (CCAT1) (P = 0.006) and HOXA transcript at the distal tip (HOTTIP) (P = 0.049), but not X-inactive specific transcript (XIST) (P = 0.12), were significantly upregulated in CRC patients compared to healthy individuals. However, there were no significant correlations between platelet lncRNAs and clinicopathological characteristics, including sex, age, tumor location, differentiation, and size (all at P > 0.05). The area under the ROC curve (AUC) of the lncRNA CCAT1 was 0.61 (sensitivity, 71%; specificity, 50%). TEP lncRNA CCAT1 is detectable in the circulation of CRC patients and could be considered as a potential diagnostic biomarker.

LncRNA XIST Interacts with Regulatory T Cells within the Tumor Microenvironment in Chronic Hepatitis B-Associated Hepatocellular Carcinoma.

Alterations in the expression of several long non-coding RNAs (lncRNAs) have been shown in chronic hepatitis B-associated hepatocellular carcinoma (CHB-HCC). Here, we aimed to investigate the association between the expression of inflammation-associated lncRNA X-inactive specific transcript (XIST) and the type of inflammatory cells within the tumor microenvironment. Twenty-one consecutive cirrhotic patients with CHB-HCC were included. XIST expression levels were investigated on formalin-fixed paraffin-embedded (FFPE) tumoral and peritumoral tissue samples by real-time polymerase chain reaction (RT-PCR). Immunohistochemical staining for CD3, CD4, CD8, CD25, CD163, CTLA4, and PD-1 were performed. The findings were statistically analyzed. Of the 21 cases, 11 (52.4%) had tumoral and 10 (47.6%) had peritumoral XIST expression. No significant association was found between the degree of inflammation and XIST expression. The number of intratumoral CD3, CD4, CD8 and CD20 positive cells was higher in XIST-expressing tumors, albeit without statistical significance. Tumoral and peritumoral XIST expression tended to be more common in patients with tumoral and peritumoral CD4high inflammation. The number of intratumoral CD25 positive cells was significantly higher in XIST-expressing tumors (p=0.01). Tumoral XIST expression was significantly more common in intratumoral CD25high cases (p=0.04). Peritumoral XIST expression was also more common among patients with CD25high peritumoral inflammation, albeit without statistical significance (p=0.19). lncRNA XIST is expressed in CHB-HCC and its expression is significantly associated with the inflammatory tumor microenvironment, particularly with the presence and number of CD25 (+) regulatory T cells. In vitro studies are needed to explore the detailed mechanism.

METTL14-mediated lncRNA XIST silencing alleviates GDM progression by facilitating trophoblast cell proliferation and migration via the miR-497-5p/FOXO1 axis.

Gestational diabetes mellitus (GDM),a prevalent complication during the gestation period, has been linked to impaired proliferation and migration of trophoblasts causing placental maldevelopment. We previously found that lncRNA X-inactive specific transcript (XIST)played an essential role in GDM progression. Here, we investigated the precise biological functions as well as the upstream and downstream regulatory mechanisms of XIST in GDM. We found that XISTand forkheadbox O1 (FOXO1) were conspicuously upregulated and miR-497-5p and methyltransferase-like 14 (METTL14) were downregulated in the placentas of GDM patients. XIST silencing facilitated proliferation and migration and inhibited cell apoptosis and cell cycle arrest in HG-cultured HTR8/SVneo cells. METTL14 inhibited XIST expression through m6A methylation modification. XIST overexpression abrogated the positive effect of METTL14 overexpression on HG-cultured HTR8/SVneo cell progression. MiR-497-5p and FOXO1 are downstream regulatory genes of XIST in HTR8/SVneo cells. Reverse experiments illustrated that XIST mediated HTR8/SVneo cell functions by regulating the miR-497-5p/FOXO1 axis. Additionally, XIST silencing augmented glucose tolerance and alleviated fetal detrimental changes in GDM rats. To conclude, METTL14-mediated XIST silencing facilitated proliferation and migration and inhibited cell apoptosis and cell cycle arrest in HG-cultured HTR8/SVneo cells via the miR-497-5p/FOXO1 axis, thereby alleviating GDM progression in rats.

The Mechanisms of Long Non-coding RNA-XIST in Ischemic Stroke: Insights into Functional Roles and Therapeutic Potential.

Ischemic stroke, which occurs due to the occlusion of cerebral arteries, is a common type of stroke. Recent research has highlighted the important role of long non-coding RNAs (lncRNAs) in the development of cerebrovascular diseases, specifically ischemic stroke. Understanding the functional roles of lncRNAs in ischemic stroke is crucial, given their potential contribution to the disease pathology. One noteworthy lncRNA is X-inactive specific transcript (XIST), which exhibits downregulation during the early stages of ischemic stroke and subsequent upregulation in later stages. XIST exert its influence on the development of ischemic stroke through interactions with multiple miRNAs and transcription factors. These interactions play a significant role in the pathogenesis of the condition. In this review, we have provided a comprehensive summary of the functional roles of XIST in ischemic stroke. By investigating the involvement of XIST in the disease process, we aim to enhance our understanding of the mechanisms underlying ischemic stroke and potentially identify novel therapeutic targets.

Long noncoding RNA X-inactive specific transcript (lncRNA XIST) inhibits hepatic insulin resistance by competitively binding microRNA-182-5p.

What is highlighted in this study refers to the role and molecular mechanism of long noncoding RNA (lncRNA) X-inactive specific transcript(XIST) in cells with insulin resistance (IR). In this study, LX-2 cells were applied to establish IR model in vitro. The expressions of lncRNA XIST, phosphoenolpyruvate carboxykinase(PEPCK,) and glucose-6-phosphatase (G6Pase) were quantified by quantitativereverse transcription polymerase chain reaction. The 2-deoxy-d-glucose-6-phosphate (2-DG6P) level was detected utilizing 2-deoxy-d-glucose (2-DG) uptake measurement kit. Western blot was adopted to measure the protein expressions of insulin-like growth factor-1 receptor (IGF-1R), G6Pase, PEPCK, and phosphatidylinositol 3-kinase(PI3K)/Akt pathway-related genes. StarBase was used to predict the targeting relationship between lncRNA XIST or IGF-1R with miR-182-5p, the results of which were verified by dual-luciferase reporter, RNA pull-down, and RNA immunoprecipitation assays. Rescue experiments were conducted to investigate the effect of miR-182-5p on IR cells. Next, low-expressed lncRNA XIST and high-expressed miR-182-5p were observed in IR cells. Upregulation of lncRNA XIST increased IGF-1R and 2-DG6P levels, decreased G6Pase and PEPCK expressions, and promoted PI3K/Akt pathway activation in IR cells. LncRNA XIST sponged miR-182-5p which targeted IGF-1R. MiR-182-5p mimic reversed the above effects of lncRNA XIST overexpression on IR cells. In conclusion, lncRNA XIST/miR-182-5p axis alleviates hepatic IR in vitro via IGF-1R/PI3K/Akt signaling pathway, which could be the promising therapeutic target.

The XIST lncRNA is a sex-specific reservoir of TLR7 ligands in SLE.

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with a dramatic sex bias, affecting 9 times more women than men. Activation of Toll-like receptor 7 (TLR7) by self-RNA is a central pathogenic process leading to aberrant production of type I interferon (IFN) in SLE, but the specific RNA molecules that serve as TLR7 ligands have not been defined. By leveraging gene expression data and the known sequence specificity of TLR7, we identified the female-specific X-inactive specific transcript (XIST) long noncoding RNA as a uniquely rich source of TLR7 ligands in SLE. XIST RNA stimulated IFN-α production by plasmacytoid DCs in a TLR7-dependent manner, and deletion of XIST diminished the ability of whole cellular RNA to activate TLR7. XIST levels were elevated in blood leukocytes from women with SLE compared with controls, correlated positively with disease activity and the IFN signature, and were enriched in extracellular vesicles released from dying cells in vitro. Importantly, XIST was not IFN inducible, suggesting that XIST is a driver, rather than a consequence, of IFN in SLE. Overall, our work elucidated a role for XIST RNA as a female sex-specific danger signal underlying the sex bias in SLE.

Long non-coding RNA X-Inactive Specific Transcript (XIST) interacting with USF2 promotes osteogenic differentiation of periodontal ligament stem cells through regulation of WDR72 transcription.

Periodontal ligament stem cells (PDLSCs) are the most potential cells in periodontal tissue regeneration and bone tissue regeneration. Our prior work had revealed that WD repeat-containing protein 72 (WDR72) was crucial for osteogenic differentiation of PDLSCs. Here, we further elucidated its underlying mechanism in PDLSC osteogenic differentiation. Human PDLSCs, isolated and identified by flow cytometry, were prepared for osteogenic differentiation induction. Levels of WDR72, long non-coding RNA X-Inactive Specific Transcript (XIST), upstream stimulatory factor 2 (USF2), and osteogenic marker genes (Runx2, Osteocalcin, and Collagen I) in human PDLSCs and clinical specimens were detected by RT-qPCR. Protein expressions of WDR72, Runx2, Osteocalcin, and Colla1 were tested by Western blot. The interactions among the molecules were verified by RIP, RNA pull-down, ChIP, and luciferase reporter assays. Osteogenic differentiation was evaluated by alkaline phosphatase (ALP) and alizarin red staining (ARS). WDR72 was decreased in periodontal tissues of periodontitis patients, and overexpression reversed TNF-α-mediated suppressive effects on PDLSC osteogenic differentiation. Mechanically, XIST recruited the enrichment of USF2 to the WDR72 promoter region, thereby positively regulating WDR72. WDR72 silencing overturned XIST-mediated biological effects in PDLSCs. WDR72, regulated by the XIST/USF2 axis, enhances osteogenic differentiation of PDLSCs, implying a novel strategy for alleviating periodontitis.

Construction of lncRNA-miRNA-mRNA regulatory network in severe asthmatic bronchial epithelial cells: A bioinformatics study.

Asthma is a chronic respiratory disease caused by environment-host interactions. Bronchial epithelial cells (BECs) are the first line of defense against environmental toxins. However, the mechanisms underlying the role of BECs in severe asthma (SA) are not yet fully understood. Long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) have been shown to play important roles in the regulation of gene expression in the pathogenesis of SA. In this study, bioinformatics was used for the first time to reveal the lncRNA-miRNA-mRNA regulatory network of BECs in SA. Five mRNA datasets of bronchial brushing samples from patients with SA and healthy controls (HC) were downloaded from the Gene Expression Omnibus (GEO) database. A combination of the Venn diagram and robust rank aggregation (RRA) method was used to identify core differentially expressed genes (DEGs). Protein-protein interaction (PPI) analysis of core DEGs was performed to screen hub genes. The miRDB, miRWalk, and ENCORI databases were used to predict the miRNA-mRNA relationships, and the ENCORI and starBase v2.0 databases were used to predict the upstream lncRNAs of the miRNA-mRNA relationships. Four core DEGs were identified: carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5), interleukin-1 receptor type 2 (IL1R2), trefoil factor 3 (TFF3), and vascular endothelial growth factor A (VEGFA). These 4 core DEGs indicated that SA was not significantly associated with sex. Enrichment analysis showed that the MAPK, Rap1, Ras, PI3K-Akt and Calcium signaling pathways may serve as the principal pathways of BECs in SA. A lncRNA-miRNA-mRNA regulatory network of the severe asthmatic bronchial epithelium was constructed. The top 10 competing endogenous RNAs (ceRNAs) were FGD5 antisense RNA 1 (FGD5-AS1), metastasis associated lung adenocarcinoma transcript 1 (MALAT1), X inactive specific transcript (XIST), HLA complex group 18 (HCG18), small nucleolar RNA host gene 16 (SNHG16), has-miR-20b-5p, has-miR-106a-5p, hsa-miR-106b-5p, has-miR-519d-3p and Fms related receptor tyrosine kinase 1 (FLT1). Our study revealed a potential mechanism for the lncRNA-miRNA-mRNA regulatory network in BECs in SA.

Downregulation of lncRNA XIST may promote Th17 differentiation through KDM6A-TSAd pathway in neuromyelitis optica spectrum disorders.

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease with significant female preponderance. X inactive specific transcript (XIST) is a long non-coding RNA (lncRNA) and a key regulator of X-chromosome inactivation which is related to the sex-bias of autoimmunity. And Th17 cell proportion was significantly elevated in NMOSD according to our previous study. This study aimed to explore the expression levels of lncRNA XIST-KDM6A-TSAd pathway in lymphocytes of female NMOSD patients, and investigate its possible relationship with pathogenesis of NMOSD. The study enrolled 30 acute-phase untreated female NMOSD patients and 30 age-matched female healthy controls, their lymphocytes were collected for experiments. Microarray as well as validation experiments showed lncRNA XIST was significantly downregulated in the NMOSD group. And the levels of lysine demethylase 6A (KDM6A) decreased in NMOSD and showed significant positive correlation with XIST. The levels of T cell-specific adapter (TSAd) mRNA and protein levels were significantly lower in NMOSD. And Chromatin immunoprecipitation assay demonstrated that NMOSD had more H3K27me3 modification than control at TSAd promoter region. The present study introduced a potential pathway that following lncRNA XIST downregulation, which process may promote Th17 differentiation in NMOSD. These findings shed new light on the immune regulation mechanism about lncRNA XIST and related epigenetic features, which may contribute to develop female-specific treatment plans.

The Role of LncRNA XIST in Gynecologic Cancers

Abstract: Long non-coding RNAs (lncRNAs) are non-coding RNAs longer than 200 nucleotides that act by targeting translational and post-translational modifications, epigenetic regulators, and chromatin remodeling complexes. There has been increasing evidence that the lncRNA X-inactive specific transcript (lncRNA Xist) via targeting miRNAs and transcription factors plays a critical role in cell growth, proliferation, and differentiation. This lncRNA also has an important role in the progression of tumors and other human diseases by acting as a competing endogenous RNA (ceRNA). Accumulating evidence revealed that lncRNA Xist by targeting several signaling pathways is involved in the pathogenesis of gynecologic cancers. In this review, we focused on the recent functions of lncRNA Xist in breast, cervical, and ovarian cancers.

Silencing of long noncoding RNA X-inactive specific transcript alleviates Aβ1-42-induced microglia-mediated neurotoxicity by shifting microglial M1/M2 polarization.

This experimental study aims to investigate the role of long noncoding RNA X-inactive specific transcript (lncRNA XIST) in the microglial polarization and microglia-mediated neurotoxicity in Alzheimer's disease (AD). The levels of XIST and microRNA-107 (miR-107) were detected by quantitative real-time polymerase chain reaction. The spatial learning and memory capability of APPswe/PS1dE9 (APP/PS1) mice were evaluated by the Morris water maze test. The morphology of mouse hippocampus cells was evaluated by hematoxylin and eosin staining. The Iba1-positive microglia were labeled by immunohistochemistry staining. The protein levels were determined by western blot and enzyme-linked immunosorbent assay. Neurotoxicity was evaluated by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, caspase-3 activity, and Cell Counting Kit-8 assay. The XIST, miR-107, and AD targets were predicted by bioinformatics analysis. The level of XIST was increased in APP/PS1 mice, and XIST silencing ameliorated AD progression. XIST silencing suppressed microglia activation, microglial M1 polarization, and proinflammatory factor levels, but promoted microglial M2 polarization in APP/PS1 mice and Aβ1-42-treated BV-2 cells. XIST knockdown reduced Aβ1-42-induced microglia-mediated apoptosis and enhanced cell viability in HT22 cells. XIST silencing down-regulated miR-107 level and attenuated Aβ1-42-caused suppression of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling. Those effects of XIST silencing were attenuated by miR-107 inhibitor or LY294002. Downregulation of XIST lessened Aβ1-42-induced microglia-mediated neurotoxicity by modulating microglial M1/M2 polarization, which may be mediated by the miR-107/PI3K/Akt pathway.

LncRNA XIST facilitates hypertrophy of ligamentum flavum by activating VEGFA-mediated autophagy through sponging miR-302b-3p

BackgroundIncreasing evidences have shown that long non-coding RNAs (lncRNAs) display crucial regulatory roles in the occurrence and development of numerous diseases. However, the function and underlying mechanisms of lncRNAs in hypertrophy of ligamentum flavum (HLF) have not been report.MethodsThe integrated analysis of lncRNAs sequencing, bioinformatics analysis and real-time quantitative PCR were used to identify the key lncRNAs involved in HLF progression. Gain- and loss-function experiments were used to explore the functions of lncRNA X inactive specific transcript (XIST) in HLF. Mechanistically, bioinformatics binding site analysis, RNA pull-down, dual-luciferase reporter assay, and rescue experiments were utilized to investigate the mechanism by which XIST acts as a molecular sponge of miR-302b-3p to regulate VEGFA-mediated autophagy.ResultsWe identified that XIST was outstandingly upregulated in HLF tissues and cells. Moreover, the up-regulation of XIST strongly correlated with the thinness and fibrosis degree of LF in LSCS patients. Functionally, knockdown of XIST drastically inhibited proliferation, anti-apoptosis, fibrosis and autophagy of HLF cells in vitro and suppressed hypertrophy and fibrosis of LF tissues in vivo. Intestinally, we uncovered that overexpression of XIST significantly promoted proliferation, anti-apoptosis and fibrosis ability of HLF cells by activating autophagy. Mechanistic studies illustrated that XIST directly medullated the VEGFA-mediated autophagy through sponging miR-302b-3p, thereby enhancing the development and progression of HLF.ConclusionOur findings highlighted that the XIST/miR-302b-3p/VEGFA-mediated autophagy axis is involved in development and progression of HLF. At the same time, this study will complement the blank of lncRNA expression profiles in HLF, which laid the foundation for further exploration of the relationship between lncRNAs and HLF in the future.