EPSTI1 promotes osteoclast differentiation and bone resorption by PKR/NF-κB signaling.

BACKGROUND: Epithelial stromal interaction 1 (EPSTI1) plays an important role in M1 macrophages, which induce osteoclastogenesis. One recent genome-wide association study (GWAS) involving 426,824 individuals has shown that EPSTI1 is strongly associated with osteoporosis (P < 5E-8). Therefore, we speculate that EPSTI1 participates in the modulation of osteoporosis through osteoclastogenesis. The roles of EPSTI1 in osteoclastogenesis and bone resorption remain unclear. METHODS: Femur specimens were collected from osteoporotic patients and control patients. Immunofluorescence staining was used to detect the expression of EPSTI1 and signaling pathways. The osteoclastic potential of RAW264.7 cells with Sh-EPSTI1 lentivirus infection was tested using tartrate-resistant acid phosphatase (TRAP) staining, western blotting, and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Western blotting was also used to examine signaling pathways. RESULTS: In this study, EPSTI1 was found to be significantly increased in tartrate-resistant acid phosphatase positive (ACP5+) osteoclasts of bone sections from osteoporotic patients. Next, we identified EPSTI1 as a positive regulator of osteoclastogenesis and osteoclast differentiation capability. Diminished EPSTI1 expression resulted in reduced osteoclastic resorption. Mechanistically, EPSTI1-driven osteoclastogenesis was regulated by NF-κB pathway, which was mediated by the phosphorylation of protein kinase R (p-PKR). Furthermore, EPSTI1 participating in the modulation of osteoporosis via PKR/NF-κB pathway was also verified in the bone samples of osteoporotic patients. CONCLUSIONS: Collectively, our findings suggest that EPSTI1 may regulate osteoclast differentiation and bone resorption through PKR/NF-κB pathway and in vivo experiments are needed to further verify EPSTI1 as the therapy target for osteoporosis.

Upregulation of EPSTI1/Drp1/AKT1 Signaling Pathways Using pDNA/Melittin Against Breast Cancer.

This study investigates the role of genes related to breast cancer in apoptosis control. A melittin nucleic acid sequence was synthesized and introduced into a pcDNA3.1(+) Mammalian Expression Plasmid. The cloning accuracy was assessed using PCR testing and enzyme digestion techniques. The vectors were transfected into cells using LipofectamineTM2000. The transfection efficacy of MCF-7 and 4T1 cells was evaluated using fluorescence and bright-field imaging. Pure melittin produced from bee venom had a notable hemolytic impact, with lower hemolytic activity levels than the positive control, Triton X-100. The growth rate of 4T1 and MCF-7 cancer cells was significantly inhibited. The apoptosis rates were 8.54%, 46.20%, and 78.82% for free pDNA, melittin, and pDNA-melittin, respectively. The C-pDNA/Melittin-treated group showed a statistically significant reduction in cancer factors compared to the control group. The treated tumors exhibited significant necrosis and late apoptosis, with a prevalence ranging from about 5% to 10% of the lesions. After exposure to pDNA-melittin, there was no significant increase in transcription levels of caspase-3, caspase-8, BCRA1, BAX, Drp1, AKT1, and EPSTI1 genes in the normal non-cancerous groups. The findings provide novel opportunities for the therapeutic targeting of malignancies via melittin and the stimulation of the EPSTI1/Drp1/AKT1 signaling cascades.

EPSTI1 promotes monocyte adhesion to endothelial cells in vitro via upregulating VCAM-1 and ICAM-1 expression.

Atherosclerosis is a chronic inflammatory disease of arterial wall, and circulating monocyte adhesion to endothelial cells is a crucial step in the pathogenesis of atherosclerosis. Epithelial-stromal interaction 1 (EPSTI1) is a novel gene, which is dramatically induced by epithelial-stromal interaction in human breast cancer. EPSTI1 expression is not only restricted to the breast but also in other normal tissues. In this study we investigated the role of EPSTI1 in monocyte-endothelial cell adhesion and its expression pattern in atherosclerotic plaques. We showed that EPSTI1 was dramatically upregulated in human and mouse atherosclerotic plaques when compared with normal arteries. In addition, the expression of EPSTI1 in endothelial cells of human and mouse atherosclerotic plaques is significantly higher than that of the normal arteries. Furthermore, we demonstrated that EPSTI1 promoted human monocytic THP-1 cell adhesion to human umbilical vein endothelial cells (HUVECs) via upregulating VCAM-1 and ICAM-1 expression in HUVECs. Treatment with LPS (100, 500, 1000 ng/mL) induced EPSTI1 expression in HUVECs at both mRNA and protein levels in a dose- and time-dependent manner. Knockdown of EPSTI1 significantly inhibited LPS-induced monocyte-endothelial cell adhesion via downregulation of VCAM-1 and ICAM-1. Moreover, we revealed that LPS induced EPSTI1 expression through p65 nuclear translocation. Thus, we conclude that EPSTI1 promotes THP-1 cell adhesion to endothelial cells by upregulating VCAM-1 and ICAM-1 expression, implying its potential role in the development of atherosclerosis.

circEPSTI1 regulates ovarian cancer progression via decoying miR-942.

Increasing studies show that circular RNAs (circRNAs) play vital roles in tumour progression. But, how circRNAs function in ovarian cancer is mostly unclear. Here, we detected the expression of circEPSTI1 in ovarian cancer and explored the function of circEPSTI1 in ovarian cancer via a series of experiments. Then, we performed luciferase assay and RNA immunoprecipitation (RIP) assay to explore the competing endogenous RNA (ceRNA) function of circEPSTI1 in ovarian cancer. qRT-PCR verified that circEPSTI1 was overexpressed in ovarian cancer. Inhibition of circEPSTI1 suppressed ovarian cancer cell proliferation, invasion but promoted cell apoptosis. Luciferase assays and RIP assay showed that circEPSTI1 and EPSTI1 (epithelial stromal interaction 1) could directly bind to miR-942. And circEPSTI1 could regulate EPSTI1 expression via sponging miR-942. In summary, circEPSTI1 regulated EPSTI1 expression and ovarian cancer progression by sponging miR-942. circEPSTI1 could be used as a biomarker and therapeutic target in ovarian cancer.

Regulation of inflammatory gene expression in macrophages by epithelial-stromal interaction 1 (Epsti1).

Epithelial-stromal interaction 1 (EPSTI1) was first discovered as a gene induced in breast cancer epithelial cells by co-cultured stromal fibroblasts. There are many reports on the role of Epsti1 in cancer malignancy. Epsti1 is now well known in regulating cancer. Recently, the role of Epsti1 in the immune response has been reported; these reports suggest the role of Epsti1 in immune function, immune privilege, and autoimmune diseases. Furthermore, they show that Epsti1 is expressed in various types of immune cells. In this study, we observed that Epsti1 is highly expressed in macrophages exposed to IFNγ and lipopolysaccharide (LPS), which classically activates macrophages. Polarization of macrophage to classically activated (M1) or alternatively activated (M2) is important for mounting responses against various infections. The M1 and M2 types of macrophage have a distinct role in the immune system. However, the molecular mechanism of modulation of the macrophage type is not well defined. Our results showed that the M2 type macrophage phenotype is enhanced in Epsti1-deficient bone marrow-derived macrophages (BMDM). In addition, Epsti1 deficiency suppresses induction of pro-inflammatory genes in BMDMs via inhibition of Stat1 and p65 nuclear localization and phosphorylation. Surprisingly, Epsti1-/- mice show decreased numbers of M1 macrophages in the peritoneal cavity. These findings identify Epsti1 as a modulator of macrophage activation and polarization via the Stat1 and p65 pathways, and suggest a potentially important role of Epsti1 in immunotherapies against inflammatory diseases.

Identification of EPSTI1 as a new potential biomarker for SLE based on GEO database.

OBJECTIVE: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with highly heterogeneous. The aim of this study is to find the key genes in peripheral blood mononuclear cells (PBMCs) of SLE patients and to provide a new direction for the diagnosis and treatment of lupus. METHODS: GSE121239, GSE50772, GSE81622, and GSE144390 mRNA expression profiles were obtained from the website of Gene Expression Omnibus (GEO), and differential expressed genes (DEGs) analysis was performed by R. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to elucidate signaling pathways for the DEGs. Real-time qPCR (RT-qPCR) was used to verify the key gene EPSTI1 in PBMCs of SLE patients. Finally, the correlation analysis and ROC curve analysis of EPSTI1 for SLE were performed. RESULTS: A total of 12 upregulated DEGs were identified, including MMP8, MX1, IFI44, EPSTI1, OAS1, OAS3, HERC5, IFIT1, RSAD2, USP18, IFI44L, and IFI27. GO and KEGG pathway enrichment analysis showed that those DEGs were mainly concentrated in the response to virus and IFN signaling pathways. Real-time qPCR (RT-qPCR) revealed that EPSTI1 was increased in PBMCs of SLE. EPSTI1 was positively correlated with SLEDAI score in SLE patients. Besides, EPSTI1 was positively correlated with T cell activation- or differentiation-associated genes (BCL6 and RORC). Furthermore, ROC analyses proved EPSTI1 may have diagnostic value for SLE. CONCLUSION: Together, EPSTI1 was found to be a potential biomarker for SLE, closely related to T cell immune imbalance. Key Points • EPSTI1 expression was significantly increased in PBMCs of SLE patients. • EPSTI1 was positively correlated with disease activity and T cell activation- or differentiation-associated genes in SLE patients. • EPSTI1 might have a good diagnostic value for SLE.

Epsti1 Regulates the Inflammatory Stage of Early Muscle Regeneration through STAT1-VCP Interaction.

During muscle regeneration, interferon-gamma (IFN-γ) coordinates inflammatory responses critical for activation of quiescent muscle stem cells upon injury via the Janus kinase (JAK) - signal transducer and activator of transcription 1 (STAT1) pathway. Dysregulation of JAK-STAT1 signaling results in impaired muscle regeneration, leading to muscle dysfunction or muscle atrophy. Until now, the underlying molecular mechanism of how JAK-STAT1 signaling resolves during muscle regeneration remains largely elusive. Here, we demonstrate that epithelial-stromal interaction 1 (Epsti1), an interferon response gene, has a crucial role in regulating the IFN-γ-JAK-STAT1 signaling at early stage of muscle regeneration. Epsti1-deficient mice exhibit impaired muscle regeneration with elevated inflammation response. In addition, Epsti1-deficient myoblasts display aberrant interferon responses. Epsti1 interacts with valosin-containing protein (VCP) and mediates the proteasomal degradation of IFN-γ-activated STAT1, likely contributing to dampening STAT1-mediated inflammation. In line with the notion, mice lacking Epsti1 exhibit exacerbated muscle atrophy accompanied by increased inflammatory response in cancer cachexia model. Our study suggests a crucial function of Epsti1 in the resolution of IFN-γ-JAK-STAT1 signaling through interaction with VCP which provides insights into the unexplored mechanism of crosstalk between inflammatory response and muscle regeneration.

High-resolution transcriptomics analysis of CXCL13+ EPSTI1+ CDK1+ cells with a specific focus on lung adenocarcinoma.

Background: Programmed cell death ligand 1 (PD-L1) blocking therapy has transformed the treatment of lung adenocarcinoma (LUAD), which has significantly changed the landscape of immunotherapy. We aimed to explore specific cell subpopulations to understand tumor progression and identify markers of response to PD-L1 blocking therapy. Methods: Bulk, fluorescence-activated cell sorting (FACS), and single-cell RNA (scRNA) sequencing were used to profile CXCL13, EPSTI1, and CDK1. The gene set variation analysis (GSVA) R package was utilized for score calculation, and prognostic analyses included receiver operating characteristic (ROC) curves, Cox proportional hazard models, and meta-analysis. Additionally, we analyzed tumor microenvironment (TME), genomics, compound perturbations, and clinical indicators. The high-dimensional analysis captured the intrinsic characteristics of the subpopulation. Furthermore, subpopulation differential genes were used for enrichment analysis of transcription factors and compounds. Results: Literature and website analyses supported the essential role of CXCL13, CDK1, and EPSTI1 in immunotherapy. This led us to focus specifically on LUAD by representing a pan-cancer profile of immune-sensitive genes. Logically, the high-characteristic population may consist of samples positive for CXCL13, EPSTI1, and CDK1. The three-gene signature was a favorable indicator of immunotherapy response in the Stand Up to Cancer-Mark Foundation (SU2C-MARK) LUAD cohort but showed a poor prognosis before treatment in the Lung Cancer Explorer (LCE) database. Further mechanistic exploration revealed specific mutations associated with the three-gene signature in SU2C-MARK LUAD, such as STK11. In The Cancer Genome Atlas (TCGA)-LUAD cohort, the high-scoring group exhibited a higher tumor mutational burden (TMB) and global methylation but a lower fraction genome altered (FGA) and estimated tumor purity. Moreover, dasatinib demonstrated sensitivity in the high-scoring group. The co-localization of the CXCL13, EPSTI1, and CDK1 subpopulation was validated through spatial transcriptome and immunohistochemical databases. Assessment of the subpopulation depicted high-resolution intercellular communication. Maintenance of specific pathways, such as TNF, CD74, and CD44, contributed to immunotherapy sensitivity. Finally, the subpopulation-enriched targets and drugs were confirmed through ConnectivityMap (CMAP) analysis and multi-omics, respectively. Conclusions: In this study, positive samples for CXCL13, EPSTI1, and CDK1 exhibited poor prognostic significance in treatment-naïve LUAD cases but demonstrated benefits from PD-L1 blockade and dasatinib therapies.

Sevoflurane suppresses the malignant progression of breast cancer via the hsa_circ_0000129/miR-578/EPSTI1 axis.

BACKGROUND: Sevoflurane (Sev) is a commonly used volatile anesthetic that might suppress the process of breast cancer. Also, circular RNAs (circRNAs) have been reported to partake in the pathogenesis of breast cancer. Accordingly, this research was designed to investigate the mechanism of hsa_circ_0005962 on Sev-mediated breast cancer development. METHODS: Sev was applied to treat breast cancer cells. Cell proliferation ability, migration, invasion, and apoptosis were detected using Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), Transwell, and flow cytometry assay. Proliferating cell nuclear antigen (PCNA), Matrix metallopeptidase 9 (MMP9), B-cell lymphoma-2 (Bcl-2)-associated X protein (Bax), and Epithelial stromal interaction 1 (EPSTI1) were assessed using western blot assay. circ_0000129, microRNA-578 (miR-578), and EPSTI1 levels were determined using real-time quantitative polymerase chain reaction (RT-qPCR). Using bioinformatics software (Circinteractome and Targetscan), the binding between miR-578 and circ_0000129 or EPSTI1 were predicted, and proved using dual-luciferase reporter and RNA pull-down assay. The biological roles of circ_0000129 and Sevoflurane on tumor growth were analyzed using a xenograft tumor model in vivo. RESULTS: Sevoflurane blocked tumor cell proliferation, migration, invasion, and promoted apoptosis. Circ_0000129 and EPSTI1 expression were increased, and miR-578 was decreased in breast cancer cells. Also, they presented an opposite trend in Sev-treated tumor cells. Circ_0000129 upregulation might abolish Sev-mediated tumor progression in vitro. Mechanically, circ_0000129 can affect EPSTI1 expression by sponging miR-578. Sev might inhibit tumor growth by regulating circ_0000129 in vivo. CONCLUSION: Circ_0000129 relieved Sev-triggered suppression impacts on breast cancer development partly via the miR-578/EPSTI1 axis, which provides a new mechanism for studying mediated therapy of breast cancer treatment.

EPSTI1 as an immune biomarker predicts the prognosis of patients with stage III colon cancer.

Objective: The poor prognosis and heterogeneity of stage III colon cancer (CC) suggest the need for more prognostic biomarkers. The tumor microenvironment (TME) plays a crucial role in tumor progression. We aimed to explore novel immune infiltration-associated molecules that serve as potential prognostic and therapeutic targets. Methods: TME immune scores were calculated using "TMEscore" algorithm. Differentially expressed genes between the high and low TME immune score groups were identified and further investigated through a protein-protein interaction network and the Molecular Complex Detection algorithm. Cox regression, meta-analysis and immunohistochemistry were applied to identify genes significantly correlated with relapse-free survival (RFS). We estimated immune infiltration using three different algorithms (TIMER 2.0, CIBERSORTx, and TIDE). Single-cell sequencing data were processed by Seurat software. Results: Poor RFS was observed in the low TME immune score groups (log-rank P < 0.05). EPSTI1 was demonstrated to be significantly correlated with RFS (P < 0.05) in stage III CC. Meta-analysis comprising 547 patients revealed that EPSTI1 was a protective factor (HR = 0.79, 95% CI, 0.65-0. 96; P < 0.05)). More immune infiltrates were observed in the high EPSTI1 group, especially M1 macrophage and myeloid dendritic cell infiltration (P < 0.05). Conclusion: The TME immune score is positively associated with better survival outcomes. EPSTI1 could serve as a novel immune prognostic biomarker for stage III CC.

Contrasting functions of the epithelial­stromal interaction 1 gene, in human oral and lung squamous cell cancers.

The epithelial­stromal interaction 1 gene (EPSTI1) is known to play multiple roles in the malignant progression of breast cancer and also in some aspects of the immune responses to the tumor. However, the relevance of the gene in the onset/progression of oral squamous cell carcinoma (OSCC) and lung squamous cell carcinoma (LSCC) is not yet known. The present study was aimed at revealing the roles of EPSTI1 in conferring malignant characteristics to OSCC and LSCC, and the underlying mechanisms. Quantitative real­time polymerase chain reaction (PCR) and western blot analyses demonstrated significant upregulation of EPSTI1 in all four OSCC cell lines (HSC2, HSC3, HSC3­M3 and HSC4), and significant downregulation of EPST11 in all three LSCC cell lines (LK­2, EBC­1 and H226) used in the present study, as compared to the expression levels in the corresponding control cell lines. Both knockdown of EPST11 in OSCC and overexpression of the gene in LSCC suppressed cell proliferation, and induced cell­cycle arrest in the G1 phase, with upregulation of p21 and downregulation of CDK2 and cyclin D1. Furthermore, these alterations of EPST11 gene expression in the OSCC and LSCC cell lines suppressed the cell migration ability and reversed the EMT phenotype of the tumor cells. Collectively, while EPSTI1 appears to have oncogenic roles in OSCC, it appears to exert tumor­suppressive roles in LSCC. PCR array analyses revealed some genes whose expression levels were altered along with the modified EPSTI1 expression in both the OSCC and LSCC cell lines. These findings suggest that EPSTI1 may be a therapeutic target for both OSCC and LSCC.

Pro-Inflammatory Cytokines Promote the Transcription of Circular RNAs in Human Pancreatic ß Cells.

Circular RNAs (circRNAs) have recently been implicated in impaired ß-cell function in diabetes. Using microarray-based profiling of circRNAs in human EndoC-ßH1 cells treated with pro-inflammatory cytokines, this study aimed to investigate the expression and possible regulatory roles of circRNAs in human ß cells. We identified ~5000 ß-cell-expressed circRNAs, of which 84 were differentially expressed (DE) after cytokine exposure. Pathway analysis of the host genes of the DE circRNAs revealed the enrichment of cytokine signaling pathways, indicative of circRNA transcription from inflammatory genes in response to cytokines. Multiple binding sites for ß-cell-enriched microRNAs and RNA-binding proteins were observed for the highly upregulated circRNAs, supporting their function as 'sponges' or 'decoys'. We also present evidence for circRNA sequence conservation in multiple species, the presence of cytokine-induced regulatory elements, and putative protein-coding potential for the DE circRNAs. This study highlights the complex regulatory potential of circRNAs, which may play a crucial role during immune-mediated ß-cell destruction in type 1 diabetes.

Integrative RNA profiling of TBEV-infected neurons and astrocytes reveals potential pathogenic effectors.

Tick-borne encephalitis virus (TBEV), the most medically relevant tick-transmitted flavivirus in Eurasia, targets the host central nervous system and frequently causes severe encephalitis. The severity of TBEV-induced neuropathogenesis is highly cell-type specific and the exact mechanism responsible for such differences has not been fully described yet. Thus, we performed a comprehensive analysis of alterations in host poly-(A)/miRNA/lncRNA expression upon TBEV infection in vitro in human primary neurons (high cytopathic effect) and astrocytes (low cytopathic effect). Infection with severe but not mild TBEV strain resulted in a high neuronal death rate. In comparison, infection with either of TBEV strains in human astrocytes did not. Differential expression and splicing analyses with an in silico prediction of miRNA/mRNA/lncRNA/vd-sRNA networks found significant changes in inflammatory and immune response pathways, nervous system development and regulation of mitosis in TBEV Hypr-infected neurons. Candidate mechanisms responsible for the aforementioned phenomena include specific regulation of host mRNA levels via differentially expressed miRNAs/lncRNAs or vd-sRNAs mimicking endogenous miRNAs and virus-driven modulation of host pre-mRNA splicing. We suggest that these factors are responsible for the observed differences in the virulence manifestation of both TBEV strains in different cell lines. This work brings the first complex overview of alterations in the transcriptome of human astrocytes and neurons during the infection by two TBEV strains of different virulence. The resulting data could serve as a starting point for further studies dealing with the mechanism of TBEV-host interactions and the related processes of TBEV pathogenesis.

MiR-654-5p attenuates breast cancer progression by targeting EPSTI1.

MicroRNAs (miRNAs) dysregulation is a common event in a variety of human diseases including breast cancer. However, clinical relevance and biological role of miR-654-5p in the progression of breast cancer remain greatly elusive. Herein, the expression levels of miR-654-5p were aberrantly downregulated in human breast cancer specimens and four breast cancer cell lines. Low expression of miR-654-5p was strongly associated with advanced TNM stage and lymph node metastasis as well as a poor survival. Functional analysis showed that miR-654-5p overexpression inhibited cell growth and invasion, and induced cell apoptosis in two aggressive breast cancer cells. Further studies demonstrated that Epithelial stromal interaction 1 (EPSTI1) was a direct target gene of miR-654-5p and showed an inverse correlation with miR-654-5p expression. Forced expression of EPSTI1 could abrogate the inhibitory effect of miR-654-5p on the growth and invasion of breast cancer cells as well as apoptosis-induced ability. In conclusion, the present study highlights that miR-654-5p acts as a tumor suppressor in breast cancer through directly targeting EPSTI1, and their functional regulation may open a novel avenue with regard to the therapeutic target for breast cancer.