XIST Knockdown Research Articles

LncRNA XIST promotes neovascularization in diabetic retinopathy by regulating miR-101-3p/VEGFA.

This study sought to investigate the regulation of long noncoding RNA (lncRNA) XIST on the microRNA (miR)-101-3p/vascular endothelial growth factor A (VEGFA) axis in neovascularization in diabetic retinopathy (DR). Serum of patients with DR was extracted for the analysis of XIST, miR-101-3p, and VEGFA expression levels. High glucose (HG)-insulted HRMECs and DR model rats were treated with lentiviral vectors. MTT, transwell, and tube formation assays were performed to evaluate cell viability, migration, and angiogenesis, and ELISA was conducted to detect the levels of inflammatory cytokines. Dual-luciferase reporter, RIP, and RNA pull-down experiments were used to validate the relationships among XIST, miR-101-3p, and VEGFA. XIST and VEGFA were upregulated and miR-101-3p was downregulated in serum from patients with DR. XIST knockdown inhibited proliferation, migration, vessel tube formation, and inflammatory responsein HG-treated HRMECs, whereas the above effects were nullified by miR-101-3p inhibition or VEGFA overexpression. miR-101-3p could bind to XIST and VEGFA. XIST promoted DR development in rats by regulating the miR-101-3p/VEGFA axis. LncRNA XIST promotes VEGFA expression by downregulating miR-101-3p, thereby stimulating angiogenesis and inflammatory response in DR.

Polysaccharides from Dendrobium officinale delay diabetic kidney disease interstitial fibrosis through LncRNA XIST/TGF-β1

PurposeRenal interstitial fibrosis is a pathological manifestation of the progression of diabetic kidney disease (DKD). Dendrobium officinale polysaccharides (DOP), one of the major active components of Dendrobium officinale, have hypoglycemic and hypolipidemic effects and are used clinically to treat diabetes. However, the role of DOP in delaying DKD progression remains unclear. This study aimed to explore the potential mechanisms by which DOP delays DKD renal interstitial fibrosis. MethodsUsing db/db mice as a model of DKD, we administered DOP by gavage and observed its therapeutic effectiveness. Employing ASO technology, we knocked down lncRNA XIST expression in kidney tissues and detected the expression of lncRNA XIST, TGF-β1, and renal interstitial fibrosis-related molecules. ResultsDOP was primarily composed of monosaccharides, with 91.57% glucose and 1.41% mannose, forming a spheroid-like structure. It has a high polydispersity index with an Mw/Mn of 6.146, and the polysaccharides are mainly connected by 4-Man(p) and 4-Glc(p) linkages. In the kidneys of db/db mice, lncRNA XIST and TGF-β1 are highly expressed; however, their expression is significantly reduced after gastric infusion with DOP, and upon knockdown of lncRNA XIST, it might delay the progression of renal interstitial fibrosis in DKD. ConclusionDOP may delay the progression of DKD renal interstitial fibrosis through the regulation of the LncRNA XIST/TGF-β1 related fibrotic pathway. This provides a new perspective for clinical strategies to delay the progression of DKD renal interstitial fibrosis.

Effect of lncRNA XIST on acute myeloid leukemia cells via miR-142-5p-PFKP axis

ABSTRACT Acute myeloid leukemia (AML) is the common blood cancer in hematopoietic system-related diseases and has a poor prognosis. Studies have shown that long non-coding RNAs (lncRNAs) are closely related to the pathogenesis of a variety of diseases, including AML. However, the specific molecular mechanism remains unclear. Hence, the objective of this study was to investigate the effect and mechanism of lncRNA X inactive specific transcript (lncRNA XIST) on AML. To achieve our objective, some tests were performed. Quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to detect the expression of lncRNA XIST, miR-142-5p and the platelet isoform of phosphofructokinase (PFKP). The targeting relationship between miR-142-5p and lncRNA XIST and PFKP was verified by Pearson correlation analysis, dual-luciferase reporter assay, and pull-down assay. Functional experiments were used to analyze the effect and mechanism of action of knocking down lncRNA XIST on THP-1 and U937 cells. Compared with bone marrow cells, lncRNA XIST and PFKP expression levels were up-regulated and miR-142-5p expression levels were down-regulated in AML. Further analysis revealed that lncRNA XIST targeted and bound to miR-142-5p, and PFKP was a target gene of miR-142-5p. Knockdown of lncRNA XIST significantly promoted miR-142-5p expression to down-regulate PFKP in THP-1 and U937 cells, while the cell proliferation, cell viability, and cell cycle arrest were inhibited and apoptosis was increased. Knockdown of miR-142-5p reversed the functional impact of lncRNA XIST knockdown on AML cells. In conclusion, down-regulation of lncRNA XIST can affect the progression of AML by regulating miR-142-5p.

LncRNA xist regulates sepsis associated neuroinflammation in the periventricular white matter of CLP rats by miR-122-5p/PKCη Axis.

Neuroinflammation is a common feature of many neurological diseases, and remains crucial for disease progression and prognosis. Activation of microglia and astrocytes can lead to neuroinflammation. However, little is known about the role of lncRNA xist and miR-122-5p in the pathogenesis of sepsis-associated neuroinflammation (SAN). This study aims to investigate the role of lncRNA xist and miR-122-5p in the pathogenesis of SAN. Levels of miR-122-5p and proinflammatory mediators were detected in the cerebrospinal fluid (CSF) of patients with intracranial infection (ICI) by ELISA and qRT-PCR. miRNA expression in the periventricular white matter (PWM) in rats was analyzed by high-throughput sequencing. Levels of lncRNA xist, miR-122-5p and proinflammatory mediators in the PWM were measured using qRT-PCR and western blot. Bioinformatics analysis was used to predict the upstream and downstream of miR-122-5p. The interaction between miR-122-5p and its target protein was validated using luciferase reporter assay. BV2 and astrocytes were used to detect the expression of lncRNA xist, miR-122-5p. The level of miR-122-5p was significantly decreased in the CSF of ICI patients, while the expression of IL-1β and TNF-α were significantly upregulated. Furthermore, it was found that the expression of IL-1β and TNF-α were negatively correlated with the level of miR-122-5p. A high-throughput sequencing analysis showed that miR-122-5p expression was downregulated with 1.5-fold changes in the PWM of CLP rats compared with sham group. Bioinformatics analysis found that lncRNA xist and PKCη were the upstream and downstream target genes of miR-122-5p, respectively. The identified lncRNA xist and PKCη were significantly increased in the PWM of CLP rats. Overexpression of miR-122-5p or knockdown of lncRNA xist could significantly downregulate the level of PKCη and proinflammatory mediators from activated microglia and astrocytes. Meanwhile, in vitro investigation showed that silencing lncRNA xist or PKCη or enhancing the expression of miR-122-5p could obviously inhibit the release of proinflammatory mediators in activated BV2 cells and astrocytes. LncRNA xist could regulate microglia and astrocytes activation in the PWM of CLP rats via miR-122-5p/PKCη axis, further mediating sepsis associated neuroinflammation.

Artemisinin suppresses aerobic glycolysis in thyroid cancer cells by downregulating HIF-1a, which is increased by the XIST/miR-93/HIF-1a pathway.

The incidence of thyroid cancer (TC) continues to increase worldwide. Aerobic glycolysis, the prominent feature of glucose metabolism in cancer progression, is associated with TC. We first demonstrated that HIF-1a is highly expressed in TC tissues and is positively correlated with the level of XIST in the serum of patients with TC. Then, we proved that XIST regulates the expression of HIF-1a through the XIST/miR-93/HIF-1a pathway, thereby regulating the level of glycolysis in TC cells. Knockdown of XIST inhibits glycolysis, proliferation, the cell cycle and metastasis of TC cells. Finally, we verified that artemisinin could target the degradation of HIF-1a and inhibit glycolysis in TC cells. Collectively, XIST levels in serum may be used as a tumor marker for TC promoted by HIF-1a, which could be treated using artemisinin.

LncRNA XIST knockdown reduces myocardial damage in myocarditis by targeting the miR-140-3p/RIPK1 axis

ABSTRACT Viral myocarditis (MC) is caused by Coxsackie virus B3 (CVB3)-induced cardiomyocyte apoptosis and inflammation, and changes in miRNA and lncRNA are linked to cardiac remodeling. The long non-coding RNA XIST (XIST) has been identified as a regulator in various pathological processes in heart diseases, but its role in CVB3-induced MC is not well understood. This research aimed to evaluate the impact that XIST has on CVB3-induced MC as well as the mechanism behind this effect. XIST expression in CVB3-exposed H9c2 cells (H9c2 cells) was evaluated by qRT-PCR. In CVB3-exposed H9c2 cells, reactive oxygen species production, inflammatory mediators, and apoptosis were experimentally observed. An investigation into and confirmation of the existence of an interaction involving XIST, miR-140-3p, and RIPK1 were carried out. The findings showed that CVB3 induced upregulation of XIST in H9c2 cells. However, XIST knockdown reduced oxidative stress, inflammation, and apoptosis of CVB3-exposed H9c2 cells. XIST was specifically bound to miR-140-3p, and there was mutual negative regulation between the two. Moreover, XIST downregulated RIPK1, which was mediated by miR-140-3p. The study suggests that downregulating XIST can alleviate inflammatory injury in CVB3-exposed H9c2 cells through the miR-140-3p/RIPK1 axis. These findings provide novel insights into the underlying mechanisms of MC.

LncRNA XIST regulates breast cancer stem cells by activating proinflammatory IL-6/STAT3 signaling

Aberrant expression of XIST, a long noncoding RNA (lncRNA) initiating X chromosome inactivation (XCI) in early embryogenesis, is a common feature of breast cancer (BC). However, the roles of post-XCI XIST in breast carcinogenesis remain elusive. Here we identify XIST as a key regulator of breast cancer stem cells (CSCs), which exhibit aldehyde dehydrogenase positive (ALDH+) epithelial- (E) and CD24loCD44hi mesenchymal-like (M) phenotypes. XIST is variably expressed across the spectrum of BC subtypes, and doxycycline (DOX)-inducible knockdown (KD) of XIST markedly inhibits spheroid/colony forming capacity, tumor growth and tumor-initiating potential. This phenotype is attributed to impaired E-CSC in luminal and E- and M-CSC activities in triple-negative (TN) BC. Gene expression profiling unveils that XIST KD most significantly affects cytokine-cytokine receptor interactions, leading to markedly suppressed expression of proinflammatory cytokines IL-6 and IL-8 in ALDH- bulk BC cells. Exogenous IL-6, but not IL-8, rescues the reduced sphere-forming capacity and proportion of ALDH+ E-CSCs in luminal and TN BC upon XIST KD. XIST functions as a nuclear sponge for microRNA let-7a-2-3p to activate IL-6 production from ALDH- bulk BC cells, which acts in a paracrine fashion on ALDH+ E-CSCs that display elevated cell surface IL-6 receptor (IL6R) expression. This promotes CSC self-renewal via STAT3 activation and expression of key CSC factors including c-MYC, KLF4 and SOX9. Together, this study supports a novel role of XIST by derepressing let-7 controlled paracrine IL-6 proinflammatory signaling to promote CSC self-renewal.

IRF-1-inhibited lncRNA XIST regulated the osteogenic differentiation via miR-450b/FBXW7 axis.

Osteoporosis influences life quality among elder people. Osteoblast dysfunction could cause the occurrence of osteoporosis. LncRNA XIST are involved in the progression of osteoporosis. However, the correlation between IRF-1 and XIST in osteogenic differentiation remains unclear. In the study, Clinical samples were collected for the analysis of XIST level. mRNA and protein levels were detected by RT-qPCR and western blot, respectively. H&E staining was performed to observe the histological changes in mice. Alizarin Red Staining was applied to assess the calcium deposits in hBMSCs. Meanwhile, the relation among XIST, miR-450b and FBXW7 was investigated by dual luciferase assay and ChIP. In vivo model was constructed to assess the impact of XIST in osteoporosis. XIST was found to be upregulated in osteoporosis, and XIST overexpression could inhibit the osteogenic differentiation in hBMSCs. IRF-1 could transcriptionally inhibit the expression of XIST, and XIST could inhibit osteogenic differentiation through binding with miR-450b in hBMSCs. In addition, miR-450b significantly promoted the osteogenic differentiation in hBMSCs via targeting FBXW7. Furthermore, XIST knockdown could inhibit the symptom of osteoporosis in vivo. IRF-1 promoted the osteogenic differentiation via mediation of lncRNA XIST/miR-450b/FBXW7 axis, and this finding might shed novel insights on exploring new ideas against osteoporosis.

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.

IncRNA XIST Stimulates Papillary Thyroid Cancer Development through the miR-330-3p/PDE5A Axis

Long non-coding RNAs (lncRNAs) possess both tumor suppressive and oncogenic functions in papillary thyroid cancer (PTC). Among all the thyroid cancers, PTC is the most prevalent form. Herein, we aim to determine the regulatory mechanisms and functions of lncRNA XIST in the multiplication, invasion, and survival of PTC. Quantitative reverse transcription polymerase chain reaction and Western blot experiments were performed to determine the patterns of lncRNA XIST, miR-330-3p, and PDE5A expressions. The subcellular localization of XIST was determined through subcellular fractionation. Bioinformatics analyses were performed to determine miR-330-3p's relationships with XIST and PDE5A, which were further confirmed through luciferase reporter assays. Loss-of-function combined with Transwell, CCK-8, and caspase-3 activity experiments were performed to determine the mechanism of the XIST/miR-330-3p/PDE5A axis in regulating the malignancy of PTC cells. Xenograft tumor experiment was employed to study the influence of XIST on tumor development in vivo. The PTC cell lines and tissues manifested considerably high levels of lncRNA XIST expression. The XIST knockdown inhibited proliferation, blocked migration, and strengthened apoptosis among PTC cells. Moreover, its knockdown suppressed PTC tumor development in vivo. XIST repressed miR-330-3p to stimulate the malignant behaviors of PTC. Through the downregulation of PDE5A, miR-330-3p attenuated the capability of PTC cells to grow, migrate, and survive. lncRNA XIST promotes tumor development in PTC through the regulation of the miR-330-3p/PDE5A axis. The findings from this study provide new insights into the treatment of PTC.

Sinomenine Suppressed Keratinocyte Proliferation and Imiquimod-Induced Psoriasis-Like Dermatitis by Regulating lncRNA XIST

Background: Psoriasis is a chronic inflammatory skin disease. Sinomenine (SIN) has anti-inflammatory and antioxidant effects. Objective: The objective of this study was to confirm the anti-inflammatory effects and mechanism of SIN in imiquimod (IMQ)-induced psoriasis-like mouse model and IMQ-induced differentiated human keratinocytes (HaCaT) cells. Methods: BALB/c mice were treated with IMQ to construct a psoriasis-like mice model. PASI score and HE staining were used to observe pathology injury of skin tissue. The secretion of inflammatory factors and the oxidative stress level were detected by ELISA. HaCaT cells after induction of differentiation were treated with IMQ (100 μM) and SIN (10 μg/mL or 50 μg/mL), cell viability, the secretion of inflammatory factors, and the oxidative stress level were detected by MTT assay, ELISA, respectively. The expression of lncRNA XIST was detected by RT-qPCR. The relationship between XIST and EIF4G2 protein was detected by RNA immunoprecipitation (RIP) assay and ubiquitination experiment. Results: SIN significantly reduced PASI score, epidermal thickness, inflammatory response, and oxidative stress levels that increased by IMQ in vivo. SIN inhibited IMQ-induced HaCaT cell proliferation, inflammatory response, and oxidative stress levels and decreased the expression of XIST. Overexpression of XIST negated the protective effect of SIN on HaCaT cells. XIST interacted directly with EIF4G2 and regulated EIF4G2 expression via K48 ubiquitin. Knockdown of XIST reduced the half-life of EIF4G2 and decreased EIF4G2 protein stability. In addition, the E3 ubiquitin protein ligase MDM2 interacted with EIF4G2 and downregulated EIF4G2 expression. XIST reduced the interaction between MDM2 and EIF4G2, which mediated EIF4G2 K48 ubiquitination. Overexpression of XIST negated the protective effect of SIN on the inflammation of HaCaT cells through activating the NF-κB signaling pathway, while NF-κB pathway inhibitor PDTC reversed this result. Conclusion: SIN had a protective effect on psoriasis and could inhibit HaCaT cell proliferation and inflammatory response via XIST/MDM2/EIF4G2/NF-κB axis.

LncXIST Facilitates Iron Overload and Iron Overload-Induced Islet Beta Cell Injury in Type 2 Diabetes through miR-130a-3p/ALK2 Axis.

Iron overload is directly associated with diabetes mellitus, loss of islet beta cell, and insulin resistance. Likewise, long noncoding RNA (lncRNA) is associated with type 2 diabetes (T2D). Moreover, lncRNAs could be induced by iron overload. Therefore, we are going to explore the molecular mechanism of lncRNA XIST in iron overload-related T2D. Real-time quantitative PCR and Western blot were used to detect gene and protein levels, respectively. TUNEL and MTT assay were performed to examine cell survival. The glucose test strip, colorimetric analysis kit, ferritin ELISA kit, and insulin ELISA kit were performed to examine the levels of glycolic, iron, and total iron-binding capacity, ferritin, and insulin in serum. Fluorospectrophotometry assay was used to examine labile iron pool level. XIST was higher expressed in T2D and iron overload-related T2D rat tissues and cells, and iron overload-induced promoted XIST expression in T2D. Higher XIST expression was associated with iron overload in patients with T2D. Knockdown of XIST alleviated iron overload and iron overload-induced INS-1 cells injury. Further, we found that XIST can sponge miR-130a-3p to trigger receptor-like kinase 2 (ALK2) expression. Moreover, knockdown of ALK2 alleviated iron overload and iron overload-induced INS-1 cells injury by inhibiting bone morphogenetic protein 6 (BMP6)/ALK2/SMAD1/5/8 axis but reversed with XIST upregulation, which was terminally boosted by overexpression of miR-130a-3p. XIST has the capacity to promote iron overload and iron overload-related T2D initiation and development through inhibition of ALK2 expression by sponging miR-130a-3p, and that targeting this axis may be an effective strategy for treating patients with T2D.

RNAi-mediated knockdown of Xist improves development of the female buffalo (Bubalus bubalis) nuclear transfer embryos

Xist plays a critical role in the X-chromosome inactivation (XCI), an important epigenetic reprogramming of somatic cell nuclear transfer (SCNT) embryos. Modulation of Xist expression enhanced the developmental ability of mouse cloned embryos. However, the roles of Xist in buffalo SCNT embryos remain unknown. In this study, we investigated the methylation and expression status of Xist in different genders of buffalo donor cells and various stages (two-cell, eight-cell, morula and blastocyst) of in vitro fertilization (IVF) and SCNT embryos. The methylation of Xist in SCNT-♀ and SCNT-♂ embryos was aberrant hypomethylation compared with the buffalo foetal fibroblast (♀-BFF and ♂-BFF), IVF-♀ and IVF-♂ embryos. At the eight-cell stage, Xist expression was significantly higher in SCNT-♀ embryos compared with those in SCNT-♂, IVF-♀ and IVF-♂ embryos (P < 0.05). Meanwhile, no significant difference was found between IVF-♀ and IVF-♂ embryos (P > 0.05). Accordingly, we suppressed Xist expression by RNAi-Xist in SCNT-♀ embryos. Results showed that injection of Xist-shRNA significantly improved the morula and blastocyst rates (P < 0.05). These results indicated that correcting the abnormal expression of the Xist gene contributed to the development of SCNT-♀ embryos.

Mechanism of LncRNA XIST/ miR-101–3p/ZEB1 axis in EMT associated with silicosis

Silicosis is a systemic disease characterized by diffuse fibrosis of lung tissue. However, its pathogenesis has not been fully elucidated. Previous studies have demonstrated that there is a close relationship between EMT and pulmonary fibrosis. However, LncRNA XIST and miR-101–3p regulate the expression of ZEB1 which is a key transcription factor in the process of EMT through competitive endogenous RNA, thus affecting the process of EMT has not been reported. In this work, an experimental silicosis mouse model and cell model of TGF-β1 stimulated lung epithelial cells (A549) for 48 h are established to investigate the biological effects of LncRNA XIST/ miR-101–3p/ZEB1 axis in the EMT process. The results reveal that LncRNA XIST and ZEB1 are up-regulated while the miR-101–3p expression is down-regulated in vivo and vitro models. Furthermore, the knockdown of LncRNA XIST prevents the EMT process and the inhibition of miR-101–3p markedly promotes EMT stimulated by TGF-β1. Moreover, the results also illustrate that LncRNA XIST is mainly localized in the cytoplasm used FISH and possesses binding site with miR-101–3p which was identified as the target of ZEB1 used bioinformatics prediction website and Dual-luciferase reporter assay. The above demonstrated that LncRNA-XIST regulates ZEB1 by directly sponging miR-101–3p. To sum up, we uncovered that the up-regulated LncRNA XIST can modulate miR-101–3p and then up-regulate the expression of ZEB1, thus promoting the EMT process of alveolar epithelial cells in the process of silicosis-related pulmonary fibrosis EMT. Our study provides a new research idea for related targets of silicosis treatment.

Genetic and epigenetic determinants of reactivation of Mecp2 and the inactive X chromosome in neural stem cells.

SummaryRett syndrome may be treated by reactivating the silent copy of Mecp2 from the inactive X chromosome in female cells. Most studies that model Mecp2 reactivation have used mouse fibroblasts rather than neural cells, which would be critical for phenotypic reversal, and rely on fluorescent reporters that lack adequate sensitivity. Here, we present a mouse model based on a dual bioluminescent and fluorescent reporter to assess the level of reactivation of Mecp2 and the inactive X chromosome by treating neural stem cells with 5-azacytidine and Xist knockdown. We show that reactivation of Mecp2 and other X-linked genes correlates with CpG density, with distance from escapees, and, very strongly, with the presence of short interspersed nuclear elements. In addition, X-linked genes reactivated in neural stem cells overlap substantially with early reactivating genes by induced pluripotent stem cell reprogramming of fibroblasts or neuronal progenitors, indicating that X chromosome reactivation follows similar paths regardless of the technique or cell type used.

LncRNA XIST facilitates S1P-mediated osteoclast differentiation via interacting with FUS.

The diagnosis and treatment of osteoporosis, a frequent age-related metabolic bone disorder, remain incomprehensive and challenging. The potential regulatory role of lncRNA XIST and sphingosine kinase 1 (SPHK1) pathway need experimental investigations. RAW264.7 cells and BMMs were obtained for in vitro studies and 30ng/mL RANKL was implemented for induction of osteoclast differentiation. The suppressing of lncRNA XIST, SPHK1 and fused in sarcoma (FUS) was achieved using small hairpin RNA, while overexpression of XIST and FUS was constructed by pcDNA3.1 vector system. Tartrate-resistant acid phosphatase (TRAP) staining was used for observation of formation of osteoclasts. RNA-pulldown analysis and RNA binding protein immunoprecipitation (RIP) was implemented for measuring mRNA and protein interactions. RT-qPCR was conducted to determining mRNA expression, whereas ELISA and Western blotting assay was performed for monitoring protein expression. RANKL induced osteoclast differentiation and upregulated expression of osteoclastogenesis-related genes that included NFATc1, CTSK, TRAP and SPHK1 and the level of lncRNA XIST in both RAW264.7 cells and BMMs. However, knockdown of lncRNA XIST or suppressing SPHK1 significantly reserved the effects of RANKL. LncRNA XIST was further demonstrated to be interacted with FUS and increased the stability of SPHK1, indicating its ability in promoting osteoclast differentiation through SPHK1/S1P/ERK signaling pathway. LncRNA XIST promoted osteoclast differentiation via interacting with FUS and upregulating SPHK1/S1P/ERK pathway.

Long noncoding RNA XIST regulates brown preadipocytes differentiation and combats high-fat diet induced obesity by targeting C/EBP\u03b1

BackgroundActivation of brown adipose tissue (BAT) increases energy expenditure, which makes it an attractive therapeutic strategy for obesity. LncRNAs play an important role in adipocyte differentiation and regulation. Here we assessed the effect of lncRNA XIST on brown preadipocytes differentiation and metabolic regulation.MethodsXIST expression levels were detected in human perirenal (peri-N) and subcutaneous adipose tissues (sub-Q), brown preadipocytes and 3T3-L1 preadipocytes. XIST overexpression and knockdown experiments were performed in brown preadipocytes. XIST overexpression mouse model was established by plasmid injection through tail vein.ResultsIn human adipose tissues, XIST expression was significantly higher in female than in male individuals. In vitro, XIST expression was significantly up-regulated during brown adipocyte differentiation. XIST knockdown inhibited differentiation of brown preadipocytes, while overexpression of XIST promotes brown preadipocytes to fully differentiation. RNA Binding Protein Immunoprecipitation (RIP) experiment revealed that XIST could directly bind to C/EBPα. In vivo, XIST overexpression prevents high-fat diet induced obesity and improves metabolic dysorder in male mice.ConclusionOur results suggest that XIST combats obesity through BAT activation at least partly by combination with transcription factor C/EBPα.

LncRNA XIST induces Aβ accumulation and neuroinflammation by the epigenetic repression of NEP in Alzheimer’s disease

Alzheimer’s disease (AD) is the leading cause of dementia globally, but effective treatment is lacking. We aimed to explore lncRNA XIST role in AD and the mechanisms involved in the effect of changes in lncRNA XIST on the expression of Aβ-degrading enzymes. The mouse model of AD and the cell model induced by Aβ were established. LncRNA XIST, IDE, NEP, Plasmin, ACE, EZH2 expressions and distribution of XIST in the nucleus and cytoplasm were detected by qRT-PCR. Inflammatory cytokines IL-6, IL-1β, TNFα, IL-8, and Aβ42 levels were detected by ELISA. TUNEL was used to measure brain tissue damage. Cell proliferation was detected by CCK-8 assay. Flow cytometry detected cell apoptosis. RIP validated the combination of XIST and EZH2. ChIP verified that XIST recruits EZH2 to mediate enrichment of HEK27me3 in the NEP promoter region. The protein expression in brain tissues and cells was detected by Western blot. The expression of lncRNA XIST was increased in AD mice and cell models. Inflammation and injury of nerve cells occurred in AD mice and cell models. The knockdown of lncRNA XIST alleviated Aβ-induced neuronal inflammation and damage. LncRNA XIST affected the expression of Aβ-degrading enzyme NEP, and lncRNA XIST was negatively correlated with NEP expression in AD mice. LncRNA XIST regulated NEP expression partly through epigenetic regulation by binding with EZH2. LncRNA XIST mediated neuronal inflammation and injury through epigenetic regulation of NEP. Overall, our study found that lncRNA XIST induced Aβ accumulation and neuroinflammation by the epigenetic repression of NEP in AD.

Knockdown of lncRNA XIST prevents the epithelial-mesenchymal transition of TGF-β2-induced human lens epithelial cells via miR-124/Slug axis

Posterior capsular opacification (PCO) is linked to the pathological process of lens epithelial cells, which includes proliferation, migration, and epithelial-mesenchymal transition (EMT). Our goal was to investigate whether long noncoding RNA (lncRNA) XIST contributes to EMT via targeting miR-124/Slug axis in TGF-β2-induced SRA01/04 cells. EMT was induced by stimulating SRA01/04 cells with 10 ng/mL TGF-β2 for 24 h, and PCO microenvironment was simulated. The expressions levels of lncRNA XIST, miR-124, and Slug were measured by real-time polymerase chain reaction (RT-PCR) and western blot. The role and mechanism of lncRNA XIST in promoting EMT of TGF-β2-treated SRA01/04 cells were investigated by using cell transfection, cell counting kit-8 (CCK-8), immunofluorescence staining, transwell assay, wound-healing assay, RT-PCR, western blot and dual-luciferase reporter assay. The expression of Slug and lncRNA XIST was markedly increased, while miR-124 was downregulated in TGF-β2-treated SRA01/04 cells compared with the control group. Knockdown of lncRNA XIST reduced EMT, migration, and cell viability in TGF-β2-induced SRA01/04 cells; moreover, it adversely modulated miR-124 and adjusted the expression of Slug in SRA01/04 cells, while these effects were diminished by co-transfection with AMO-miR-124. Our data demonstrated that lncRNA XIST functioned as a competitive endogenous RNA (ceRNA) of miR-124 to modulate the expression level of Slug, thereby modulating EMT, migration, and cell viability in SRA01/04 cells. In conclusion, lncRNA XIST has a crucial role in promoting TGF-β2-induced EMT via modulating the miR-124/Slug axis in SRA01/04 cells, and it may provide a novel therapeutic option for PCO treatment.

The proliferation and migration of atherosclerosis-related HVSMCs were inhibited by downregulation of lncRNA XIST via regulation of the miR-761/BMP9 axis.

Atherosclerosis (AS) is a chronic inflammatory disease that can be caused by the proliferation and migration of human vascular smooth muscle cells (HVSMCs). Here, we found that lncRNA XIST was related to the abnormal proliferation and migration of HVSMCs, and thus, the mechanism by which XIST regulated HVSMCs was further investigated. HVSMCs were treated with oxidized low-density lipoprotein (ox-LDL, 100 μg/ml) as AS models. CCK8 assays, flow cytometry, Transwell assays and wound healing assays were applied to evaluate cell viability, cell cycle analysis, and cell migration, respectively. A dual-luciferase reporter assay was employed to verify the binding relationships between XIST and miR-761, miR-761, and BMP9. Ox-LDL induced the proliferation and migration of HVSMCs, upregulated the expression of XIST, downregulated miR-761 expression, and activated the BMP9/ALK1/endoglin pathway. Luciferase assays revealed that XIST sponged miR-761. XIST knockdown ameliorated ox-LDL-mediated effects in HVSMCs, which were largely abolished by miR-761 silencing. BMP9 was targeted-inhibited by miR-761. MiR-761 overexpression alleviated ox-LDL-mediated effects in HVSMCs. However, BMP9 overexpression abolished miR-761-mediated effects in HVSMCs treated with ox-LDL. Our findings suggested that XIST knockdown suppressed the proliferation and migration of HVSMCs by promoting miR-761, which targeted-inhibited the BMP9/ALK1/endoglin pathway.