The long noncoding RNA loc107053557 acts as a gga-miR-3530-5p sponge to suppress the replication of vvIBDV through regulating STAT1 expression

Infectious bursal disease virus (IBDV) causes immunosuppression and high mortality in young chickens. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are important regulators during viral infection. However, detailed the regulatory mechanisms of lncRNA-miRNA-mRNA have not yet been described in IBDV infection. Here, we analysed the role of lncRNA53557/gga-miR-3530-5p/STAT1 axis in very virulent IBDV (vvIBDV) infection. Evidently upregulated expression of lncRNA53557 was observed in bursa of Fabricius and DT40 cells. Meanwhile, overexpression of lncRNA53557 promoted STAT1 expression and inhibited vvIBDV replication and vice versa, indicating that the upregulation of lncRNA53557 was part of the host antiviral defence. The subcellular fractionation assay confirmed that lncRNA53557 can be localized in the cytoplasm. Further, dual-luciferase reporter, RNA pulldown, FISH and RT-qPCR assays revealed that lncRNA53557 were directly bound to gga-miR-3530-5p and had a negative regulatory relationship between them. Subsequent mechanistic analysis showed that lncRNA53557 acted as a competing endogenous RNA (ceRNA) of gga-miR-3530-5p to relieve the repressive effect of gga-miR-3530-5p on its target STAT1, as well as Mx1, OASL, and ISG15, thereby suppressing vvIBDV replication. The study reveals that a network of enriched lncRNAs and lncRNA-associated ceRNA is involved in the regulation of IBDV infection, offering new insight into the mechanisms underlying IBDV-host interaction.

Multi-omics reveals the switch role of abnormal methylation in the regulation of decidual macrophages function in recurrent spontaneous abortion

RSA, recurrent spontaneous abortion, often causes serious physical damage and psychological pressure in reproductive women with unclarified pathogenesis. Abnormal function of decidual cells and aberrant DNA methylation have been reported to cause RSA, but their association remains unclear. Here, we integrated transcriptome, DNA methylome, and scRNA-seq to clarify the regulatory relationship between DNA methylation and decidual cells in RSA. We found that DNA methylation mainly influenced the function of decidual macrophages (DMs), of which four hub genes, HLA-A, HLA-F, SQSTM1/P62, and Interferon regulatory factor 7 (IRF7), related to 22 hypomethylated CpG sites, regulated 16 hub pathways to participate in RSA pathogenesis. In particular, using transcription factor analysis, it is suggested that the upregulation of IRF7 transcription was associated with enhanced recruitment of the transcription factor STAT1 by the hypomethylated promoter region of IRF7. As the current research on DNA methylation of macrophages in the uterine microenvironment of RSA is still blank, our systematic picture of abnormal DNA methylation in regulating DM function provides new insights into the role of DNA methylation in RSA occurrence, which may aid in further prevention and treatment of RSA.

Tumor associated macrophages transfer ceruloplasmin mRNA to fibrosarcoma cells and protect them from ferroptosis

Solid tumors are characterized by hypoxic areas, which are prone for macrophage infiltration. Once infiltrated, macrophages polarize to tumor associated macrophages (TAM) to support tumor progression. Therefore, the crosstalk between TAMs and tumor cells is of current interest for the development of novel therapeutic strategies. These may comprise induction of an iron- and lipid peroxidation-dependent form of cell death, known as ferroptosis. To study the macrophage - tumor cell crosstalk we polarized primary human macrophages towards a TAM-like phenotype, co-cultured them with HT1080 fibrosarcoma cells, and analyzed the tumor cell response to ferroptosis induction. In TAMs the expression of ceruloplasmin mRNA increased, which was driven by hypoxia inducible factor 2 and signal transducer and activator of transcription 1. Subsequently, ceruloplasmin mRNA was transferred from TAMs to HT1080 cells via extracellular vesicles. In tumor cells, mRNA was translated into protein to protect HT1080 cells from RSL3-induced ferroptosis. Mechanistically this was based on reduced iron abundance and lipid peroxidation. Interestingly, in naïve macrophages also hypoxia induced ceruloplasmin under hypoxia and a co-culture of HT1080 cells with hypoxic macrophages recapitulated the protective effect observed in TAM co-cultures. In conclusion, TAMs provoke tumor cells to release iron and thereby protect them from lipid peroxidation/ferroptosis.

The Myc-associated zinc finger protein epigenetically controls expression of interferon-γ-stimulated genes by recruiting STAT1 to chromatin

The MYC-Associated Zinc Finger Protein (MAZ) plays important roles in chromatin organization and gene transcription regulation. Dysregulated expression of MAZ causes diseases, such as glioblastoma, breast cancer, prostate cancer, and liposarcoma. Previously, it has been reported that MAZ controls the proinflammatory response in colitis and colon cancer via STAT3 signaling, suggesting that MAZ is involved in regulating immunity-related pathways. However, the molecular mechanism underlying this regulation remains elusive. Here, we investigate the regulatory effect of MAZ on interferon-gamma (IFN-γ)-stimulated genes via STAT1, a protein that plays an essential role in immune responses to viral, fungal, and mycobacterial pathogens. We demonstrate that about 80% of occupied STAT1-binding sites colocalize with occupied MAZ-binding sites in HAP1/K562 cells after IFN-γ stimulation. MAZ depletion significantly reduces STAT1 binding in the genome. By analyzing genome-wide gene expression profiles in the RNA-Seq data, we show that MAZ depletion significantly suppresses a subset of the immune response genes, which include the IFN-stimulated genes IRF8 and Absent in Melanoma 2. Furthermore, we find that MAZ controls expression of the immunity-related genes by changing the epigenetic landscape in chromatin. Our study reveals an important role for MAZ in regulating immune-related gene expression.

Type I gamma phosphatidylinositol phosphate 5-kinase i5 controls cell sensitivity to interferon

The interferon signaling pathway is critical for host defense by serving diverse functions in both innate and adaptive immune responses. Here, we show that type I gamma phosphatidylinositol phosphate 5-kinase i5 (PIPKIγi5), an enzyme that synthesizes phosphatidylinositol-4,5-bisphosphate (PI4,5P2), controls the sensitivity to interferon in both human and mouse cells. PIPKIγi5 directly binds to the interferon-gamma (IFN-γ) downstream effector signal transducer and activator of transcription 1 (STAT1), which suppresses the STAT1 dimerization, IFN-γ-induced STAT1 nuclear translocation, and transcription of IFN-γ-responsive genes. Depletion of PIPKIγi5 significantly enhances IFN-γ signaling and strengthens an antiviral response. In addition, PIPKIγi5-synthesized PI4,5P2 can bind to STAT1 and promote the PIPKIγi5-STAT1 interaction. Similar to its interaction with STAT1, PIPKIγi5 is capable of interacting with other members of the STAT family, including STAT2 and STAT3, thereby suppressing the expression of genes mediated by these transcription factors. These findings identify the function of PIPKIγi5 in immune regulation.

STAT1 mediated downregulation of the tumor suppressor gene PDCD4, is driven by the atypical cadherin FAT1, in glioblastoma

STAT1 (Signal Transducer and Activator of Transcription 1), belongs to the STAT protein family, essential for cytokine signaling. Ithas been reported to have either context dependent oncogenic or tumor suppressor roles in different tumors. Earlier, we demonstrated that Glioblastoma multiforme (GBMs) overexpressing FAT1, an atypical cadherin, had poorer outcomes. Overexpressed FAT1 promotes pro-tumorigenic inflammation, migration/invasion by downregulating tumor suppressor gene, PDCD4. Here, we demonstrate that STAT1 is a novel mediator downstream to FAT1, in downregulating PDCD4 in GBMs. In-silico analysis of GBM databases as well as q-PCR analysis in resected GBM tumors showed positive correlation between STAT1 and FAT1 mRNA levels. Kaplan-Meier analysis showed poorer survival of GBM patients having high FAT1 and STAT1 expression. SiRNA-mediated knockdown of FAT1 decreased STAT1 and increased PDCD4 expression in glioblastoma cells (LN229 and U87MG). Knockdown of STAT1 alone resulted in increased PDCD4 expression. In silico analysis of the PDCD4 promoter revealed four putative STAT1 binding sites (Site1-Site4). ChIP assay confirmed the binding of STAT1 to site1. ChIP-PCR revealed decrease in the binding of STAT1 on the PDCD4 promoter after FAT1 knockdown. Site directed mutagenesis of Site1 resulted in increased PDCD4 luciferase activity, substantiating STAT1 mediated PDCD4 inhibition. EMSA confirmed STAT1 binding to the Site 1 sequence. STAT1 knockdown led to decreased expression of pro-inflammatory cytokines and EMT markers, and reduced migration/invasion of GBM cells. This study therefore identifies STAT1 as a novel downstream mediator of FAT1, promoting pro-tumorigenic activity in GBM, by suppressing PDCD4 expression.

Proteome, lysine acetylome and succinylome identify post-translational modification of STAT1 as a novel drug target in silicosis

Inhalation of crystalline silica dust induces incurable lung damage, silicosis and pulmonary fibrosis. However, the mechanisms of the lung injury remain poorly understood, with limited therapeutic options aside from lung transplantation. Post-translational modifications can regulate the function of proteins and play an important role in studying disease mechanisms. To investigate changes in post-translational modifications of proteins in silicosis, combined quantitative proteome, acetylome, and succinylome analyses were performed with lung tissues from silica-injured and healthy mice using liquid chromatography-mass spectrometry. Combined analysis was applied to the three omics datasets to construct a protein landscape. The acetylation and succinylation of the key transcription factor STAT1 were found to play important roles in the silica-induced pathophysiological changes. Modulating the acetylation level of STAT1 with geranylgeranylacetone (GGA) effectively inhibited the progression of silicosis. This report revealed a comprehensive landscape of post-translational modifications in silica-injured mouse, presented a novel therapeutic strategy targeting the post-translational level for silica-induced lung diseases.

Anti-adipogenesis effect of indole-3-acrylic acid on human preadipocytes and HFD-induced zebrafish

BACKGROUND

Obesity, defined as excessive or abnormal body fat accumulation, which could significantly increase the risk of cardiovascular disease, type 2 diabetes mellitus (T2DM) diseases and seriously affect people's quality of life. More than 2 billion people are overweight, and the incidence of obesity is increasing rapidly worldwide, it has become a widely concerned public health issue in the world. Diverse evidence show that active metabolites are involved in the pathophysiological processes of obesity.

AIMS

However, whether the downstream catabolite of tryptophan, 3-indole acrylic acid (IA), is involved in obesity remains unclear.

METHODS

We collected the samples of serum from peripheral blood of obesity and health controls, and liquid chromatography-mass spectrometry (LC-MS) was performed to identify the plasma levels of IA. Additionally, we verified the potential benefits of IA on human preadipocytes and HFD- induced zebrafish by cell viability assay, flow cytometry assay, Oil red O staining, total cholesterol (T-CHO), triglyceride (TG) and nonesterified free fatty acids (NEFA) measurements and Nile Red staining. RNA-Seq, functional analysis and western blot revealed the mechanisms underlying the function of IA.

RESULTS

We found that the content of IA in peripheral blood serum of overweight people was significantly lower than that of normal people. In addition, supplementation with IA in zebrafish larvae induced by a high fat diet (HFD) dramatically reduced HFD induced lipid accumulation. IA had no effect on proliferation and apoptosis of preadipocytes, but significantly inhibited adipogenesis of preadipocytes by down-regulate CEBPα and PPARγ. RNA-Seq and functional analysis revealed that IA regulated the adipogenesis of preadipocytes through stimulate the phosphorylation of STAT1.

CONCLUSIONS

Taken together, IA has been identified as a potent metabolite for the prevention or treatment of obesity.

STING inhibition suppresses microglia-mediated synapses engulfment and alleviates motor functional deficits after stroke

Ischemic stroke is the leading cause of adult disability. Ischemia leads to progressive neuronal death and synapse loss. The engulfment of stressed synapses by microglia further contributes to the disruption of the surviving neuronal network and related brain function. Unfortunately, there is currently no effective target for suppressing the microglia-mediated synapse engulfment. Stimulator of interferon genes (STING) is an important participant in innate immune response. In the brain, microglia are the primary cell type that mediate immune response after brain insult. The intimate relationship between STING and microglia-mediated neuroinflammation has been gradually established. However, whether STING affects other functions of microglia remains elusive. In this study, we found that STING regulated microglial phagocytosis of synapses after photothrombotic stroke. The treatment of STING inhibitor H151 significantly improved the behavioral performance of injured mice in grid-walking test, cylinder test, and adhesive removal test after stroke. Moreover, the puncta number of engulfed SYP or PSD95 in microglia was reduced after consecutive H151 administration. Further analysis showed that the mRNA levels of several complement components and phagocytotic receptors were decreased after STING inhibition. Transcriptional factor STAT1 is known for regulating most of the decreased molecules. After STING inhibition, the nucleus translocation of phosphorylated STAT1 was also suppressed in microglia. Our data uncovered the novel regulatory effects of STING in microglial phagocytosis after stroke, and further emphasized STING as a potential drug-able target for post-stroke functional recovery.

Exploring the role of CITED transcriptional regulators in the control of macrophage polarization

Macrophages are tissue resident innate phagocytic cells that take on contrasting phenotypes, or polarization states, in response to the changing combination of microbial and cytokine signals at sites of infection. During the opening stages of an infection, macrophages adopt the proinflammatory, highly antimicrobial M1 state, later shifting to an anti-inflammatory, pro-tissue repair M2 state as the infection resolves. The changes in gene expression underlying these transitions are primarily governed by nuclear factor kappaB (NF-κB), Janus kinase (JAK)/signal transducer and activation of transcription (STAT), and hypoxia-inducible factor 1 (HIF1) transcription factors, the activity of which must be carefully controlled to ensure an effective yet spatially and temporally restricted inflammatory response. While much of this control is provided by pathway-specific feedback loops, recent work has shown that the transcriptional co-regulators of the CBP/p300-interacting transactivator with glutamic acid/aspartic acid-rich carboxy-terminal domain (CITED) family serve as common controllers for these pathways. In this review, we describe how CITED proteins regulate polarization-associated gene expression changes by controlling the ability of transcription factors to form chromatin complexes with the histone acetyltransferase, CBP/p300. We will also cover how differences in the interactions between CITED1 and 2 with CBP/p300 drive their contrasting effects on pro-inflammatory gene expression.

Nodal negatively regulates osteoclast differentiation by inducing STAT1 phosphorylation

Several members of the transforming growth factor beta (TGF-β) superfamily regulate the proliferation, differentiation, and function of bone-forming osteoblasts and bone-resorbing osteoclasts. However, it is still unknown whether Nodal, a member of the TGF-β superfamily, serves a function in bone cells. In this study, we found that Nodal did not have any function in osteoblasts but instead negatively regulated osteoclast differentiation. Nodal inhibited RANKL-induced osteoclast differentiation by downregulating the expression of pro-osteoclastogenic genes, including c-fos, Nfatc1, and Blimp1, and upregulating the expression of antiosteoclastogenic genes, including Bcl6 and Irf8. Nodal activated STAT1 in osteoclast precursor cells, and STAT1 downregulation significantly reduced the inhibitory effect of Nodal on osteoclast differentiation. These findings indicate that Nodal activates STAT1 to downregulate or upregulate the expression of pro-osteoclastogenic or antiosteoclastogenic genes, respectively, leading to the inhibition of osteoclast differentiation. Moreover, the inhibitory effect of Nodal on osteoclast differentiation contributed to the reduction of RANKL-induced bone loss in vivo.

hsa_circ_0087100/hsa-miR-6743-5p affects Th1 cell differentiation by regulating STAT1 in diabetic retinopathy

Objective: To elucidate the role of the competitive endogenous RNA (ceRNA) network in immune infiltration of diabetic retinopathy (DR). Methods: We obtained differentially expressed (DE) circRNAs, miRNAs and mRNAs from the Gene Expression Omnibus database. Then, we identified immune infiltration by CIBERSORT and single-sample gene set enrichment analysis and discovered co-expression genes by weighted gene co-expression network analysis. Furthermore, STAT1-mediated Th1 differentiation was determined in DR cell models, DR patients and DR mouse models. Results: hsa_circ_0087100/hsa-miR-6743-5p/STAT1 was involved in immune infiltration of Th1 cells. Aberrant expression of the ceRNA network and STAT1-mediated Th1 differentiation was thus verified in vitro and in vivo. Conclusion: hsa_circ_0087100/hsa-miR-6743-5p/STAT1 may affect Th1 cell differentiation in DR.

LINC01686 affects LPS-induced cytokine expression via the miR-18a-5p/A20/STAT1 axis in THP-1 cells

BACKGROUND AND OBJECTIVE

Long noncoding RNAs (lncRNAs) are crucial in regulating various physiological and pathological processes, including immune responses. LINC01686 is a lncRNA with previously uncharacterized functions in immune regulation. This study aims to investigate the function of LINC01686 in lipopolysaccharide (LPS)-induced inflammatory responses in the human monocytic leukemia cell line THP-1 and its potential regulatory mechanisms involving miR-18a-5p and the anti-inflammatory protein A20.

METHOD

THP-1 cells were stimulated with LPS to induce inflammatory responses, followed by analysis of LINC01686 expression levels. The role of LINC01686 in regulating the expression of interleukin (IL)-6, IL-8, A20, and signal transducer and activator of transcription 1 (STAT1) was examined using small interfering RNA-mediated knockdown. Additionally, the involvement of miR-18a-5p in LINC01686-mediated regulatory pathways was assessed by transfection with decoy RNAs mimicking the miR-18a-5p binding sites of LINC01686 or A20 messenger RNA.

RESULTS

LINC01686 expression was upregulated in THP-1 cells following LPS stimulation. Suppression of LINC01686 enhanced LPS-induced expression of IL-6 and IL-8, mediated through increased production of reactive oxygen species. Moreover, LINC01686 knockdown upregulated the expression and activation of IκB-ζ, STAT1, and downregulated A20 expression. Transfection with decoy RNAs reversed the effects of LINC01686 suppression on A20, STAT1, IL-6, and IL-8 expression, highlighting the role of LINC01686 in sponging miR-18a-5p and regulating A20 expression.

CONCLUSION

This study provides the first evidence that LINC01686 plays a critical role in modulating LPS-induced inflammatory responses in THP-1 cells by sponging miR-18a-5p, thereby regulating the expression and activation of A20 and STAT1. These findings shed light on the complex regulatory mechanisms involving lncRNAs in immune responses and offer potential therapeutic targets for inflammatory diseases.

Single-cell and bulk RNA sequencing highlights the role of M1-like infiltrating macrophages in antibody-mediated rejection after kidney transplantation

Background

Antibody-mediated rejection (ABMR) significantly affects transplanted kidney survival, yet the macrophage phenotype, ontogeny, and mechanisms in ABMR remain unclear.

Method

We analyzed post-transplant sequencing and clinical data from GEO and ArrayExpress. Using dimensionality reduction and clustering on scRNA-seq data, we identified macrophage subpopulations and compared their infiltration in ABMR and non-rejection cases. Cibersort quantified these subpopulations in bulk samples. Cellchat, SCENIC, monocle2, and monocle3 helped explore intercellular interactions, predict transcription factors, and simulate differentiation of cell subsets. The Scissor method linked macrophage subgroups with transplant prognosis. Furthermore, hdWGCNA, nichnet, and lasso regression identified key genes associated with core transcription factors in selected macrophages, validated by external datasets.

Results

Six macrophage subgroups were identified in five post-transplant kidney biopsies. M1-like infiltrating macrophages, prevalent in ABMR, correlated with pathological injury severity. MIF acted as a primary intercellular signal in these macrophages. STAT1 regulated monocyte-to-M1-like phenotype transformation, impacting transplant prognosis via the IFNγ pathway. The prognostic models built on the upstream and downstream genes of STAT1 effectively predicted transplant survival. The TLR4-STAT1-PARP9 axis may regulate the pro-inflammatory phenotype of M1-like infiltrating macrophages, identifying PARP9 as a potential target for mitigating ABMR inflammation.

Conclusion

Our study delineates the macrophage landscape in ABMR post-kidney transplantation, underscoring the detrimental impact of M1-like infiltrating macrophages on ABMR pathology and prognosis.

PRMT1 acts as a suppressor of MHC-I and anti-tumor immunity

Cancer immunotherapies have demonstrated remarkable success; however, the majority of patients do not respond or develop resistance. Here, we conduct epigenetic gene-targeted CRISPR-Cas9 screens to identify epigenomic factors that limit CD8+ T cell-mediated anti-tumor immunity. We identify that PRMT1 suppresses interferon gamma (Ifnγ)-induced MHC-I expression, thus dampening CD8+ T cell-mediated killing. Indeed, PRMT1 knockout or pharmacological targeting of type I PRMT with the clinical inhibitor GSK3368715 enhances Ifnγ-induced MHC-I expression through elevated STAT1 expression and activation, while re-introduction of PRMT1 in PRMT1-deficient cells reverses this effect. Importantly, loss of PRMT1 enhances the efficacy of anti-PD-1 immunotherapy, and The Cancer Genome Atlas analysis reveals that PRMT1 expression in human melanoma is inversely correlated with expression of human leukocyte antigen molecules, infiltration of CD8+ T cells, and overall survival. Taken together, we identify PRMT1 as a negative regulator of anti-tumor immunity, unveiling clinical type I PRMT inhibitors as immunotherapeutic agents or as adjuncts to existing immunotherapies.

PAD4 controls tumor immunity via restraining the MHC class II machinery in macrophages

Tumor-associated macrophages (TAMs) shape tumor immunity and therapeutic efficacy. However, it is poorly understood whether and how post-translational modifications (PTMs) intrinsically affect the phenotype and function of TAMs. Here, we reveal that peptidylarginine deiminase 4 (PAD4) exhibits the highest expression among common PTM enzymes in TAMs and negatively correlates with the clinical response to immune checkpoint blockade. Genetic and pharmacological inhibition of PAD4 in macrophages prevents tumor progression in tumor-bearing mouse models, accompanied by an increase in macrophage major histocompatibility complex (MHC) class II expression and T cell effector function. Mechanistically, PAD4 citrullinates STAT1 at arginine 121, thereby promoting the interaction between STAT1 and protein inhibitor of activated STAT1 (PIAS1), and the loss of PAD4 abolishes this interaction, ablating the inhibitory role of PIAS1 in the expression of MHC class II machinery in macrophages and enhancing T cell activation. Thus, the PAD4-STAT1-PIAS1 axis is an immune restriction mechanism in macrophages and may serve as a cancer immunotherapy target.

Deacetylase Sirtuin 1 mitigates type I IFN- and type II IFN-induced signaling and antiviral immunity

Type I and type II IFNs are important immune modulators in both innate and adaptive immunity. They transmit signaling by activating JAK-STAT pathways. Sirtuin 1 (SIRT1), a class III NAD+-dependent deacetylase, has multiple functions in a variety of physiological processes. Here, we characterized the novel functions of SIRT1 in the regulation of type I and type II IFN-induced signaling. Overexpression of SIRT1 inhibited type I and type II IFN-induced interferon-stimulated response element activation. In contrast, knockout of SIRT1 promoted type I and type II IFN-induced expression of ISGs and inhibited viral replication. Treatment with SIRT1 inhibitor EX527 had similar positive effects. SIRT1 physically associated with STAT1 or STAT3, and this interaction was enhanced by IFN stimulation or viral infection. By deacetylating STAT1 at K673 and STAT3 at K679/K685/K707/K709, SIRT1 downregulated the phosphorylation of STAT1 (Y701) and STAT3 (Y705). Sirt1+/- primary peritoneal macrophages and Sirt1+/- mice exhibited enhanced IFN-induced signaling and antiviral activity. Thus, SIRT1 is a novel negative regulator of type I and type II IFN-induced signaling through its deacetylase activity.IMPORTANCESIRT1 has been reported in the precise regulation of antiviral (RNA and DNA) immunity. However, its functions in type I and type II IFN-induced signaling are still unclear. In this study, we deciphered the important functions of SIRT1 in both type I and type II IFN-induced JAK-STAT signaling and explored the potential acting mechanisms. It is helpful for understanding the regulatory roles of SIRT1 at different levels of IFN signaling. It also consolidates the notion that SIRT1 is an important target for intervention in viral infection, inflammatory diseases, or even interferon-related therapies.

Adaptive inhibition of CGAS signaling by TREX1

Mammalian cells react to the accumulation of double-stranded (ds)DNA in the cytosol by secreting antiviral and proinflammatory cytokines, notably type I interferon (IFN). Recent data reported by Tani et al. demonstrate that overactivation of this pathway is prevented by an adaptive feedback mechanism elicited by type I IFN receptors and executed by the exonuclease three prime repair exonuclease 1 (TREX1).

Human STAT1 gain of function with chronic mucocutaneous candidiasis: A comprehensive review for strengthening the connection between bedside observations and laboratory research

Germline human heterozygous STAT1 gain-of-function (GOF) variants were first discovered a common cause of chronic mucocutaneous candidiasis (CMC) in 2011. Since then, numerous STAT1 GOF variants have been identified. A variety of clinical phenotypes, including fungal, viral, and bacterial infections, endocrine disorders, autoimmunity, malignancy, and aneurysms, have recently been revealed for STAT1 GOF variants, which has led to the expansion of the clinical spectrum associated with STAT1 GOF. Among this broad range of complications, it has been determined that invasive infections, aneurysms, and malignancies are poor prognostic factors for STAT1 GOF. The effectiveness of JAK inhibitors as a therapeutic option has been established, although further investigation of their long-term utility and side effects is needed. In contrast to the advancements in treatment options, the precise molecular mechanism underlying STAT1 GOF remains undetermined. Two primary hypotheses for this mechanism involve impaired STAT1 dephosphorylation and increased STAT1 protein levels, both of which are still controversial. A precise understanding of the molecular mechanism is essential for not only advancing diagnostics but also developing therapeutic interventions. Here, we provide a comprehensive review of STAT1 GOF with the aim of establishing a stronger connection between bedside observations and laboratory research.

Solamargine Induces Hepatocellular Carcinoma Cell Apoptosis and Ferroptosis via Regulating STAT1/MTCH1 Axis

BACKGROUND

Solamargine (SM) has been shown to play anti-tumor role in hepatocellular carcinoma (HCC). However, the underlying molecular mechanisms of SM in HCC progression deserve further exploration.

METHODS

HCC cell proliferation and apoptosis were assessed by cell counting kit 8 assay, colony formation assay and flow cytometry. Ferroptosis was evaluated by detecting the levels of Fe2+, iron, MDA, ROS and GSH in HCC cells. In addition, mitochondrial carrier 1 (MTCH1) mRNA level was detected by quantitative real-time PCR. Western blot was used to test MTCH1 and signal transduction and activation of transcription 1 (STAT1) protein levels. Dual-luciferase reporter assay was employed to analyze the interaction between STAT1 and MTCH1. A mouse xenograft model was also constructed to explore the role of SM in vivo.

RESULTS

SM could potentially suppress HCC cell growth by inducing ferroptosis. MTCH1 was highly expressed in HCC tissues and cells, and its silencing inhibited HCC cell proliferation, promoted apoptosis and ferroptosis. MTCH1 expression was reduced by SM, and its overexpression reversed SM-induced HCC cell apoptosis and ferroptosis. Furthermore, STAT1 facilitated MTCH1 transcription and promoted its expression. Besides, STAT1 expression could be reduced by SM, and its overexpression abolished the decreasing effect of SM on MTCH1 expression. In vivo, SM suppressed HCC tumor growth by reducing MTCH1 expression.

CONCLUSION

SM promoted HCC cell apoptosis and ferroptosis via the STAT1/MTCH1 axis.

Valproate attenuates somatic hyperalgesia induced by orofacial inflammation combined with stress through inhibiting spinal IL-6 and STAT1 phosphorylation

Temporomandibular disorder (TMD) and fibromyalgia syndrome (FMS) may present as comorbid conditions, but treatment options are ineffective. The purpose of this study was to investigate whether valproate (VPA) attenuates somatic hyperalgesia induced by orofacial inflammation combined with stress, which represents a model of pain associated with TMD and FMS comorbidity, and to explore the potential mechanisms. The results showed that VPA inhibited somatic hyperalgesia induced by orofacial inflammation combined with stress, and down-regulated the interleukin-6 (IL-6) expression in the L4-L5 spinal dorsal horn of female rats. The anti-nociceptive effect of VPA was blocked by single or 5 consecutive day intrathecal administration of recombinant rat IL-6. Orofacial inflammation combined with stress up-regulated the ratio of phosphorylated signal transducer and activator of transcription 1 (p-STAT1) to STAT1 (p-STAT1/STAT1) in the spinal cord. VPA did not affect the STAT1 expression, while it down-regulated the ratio of p-STAT1/STAT1. The expression of STAT3 and the ratio of p-STAT3/STAT3 were not affected by orofacial inflammation combined with stress and VPA treatment. Intrathecal administration of exogenous IL-6 up-regulated the ratio of p-STAT1/STAT1. These data indicate that VPA attenuated somatic hyperalgesia induced by orofacial inflammation combined with stress via inhibiting spinal IL-6 in female rats, and the mechanism may involve the alteration of activation status of spinal STAT1. Thus, VPA may be a new candidate analgesic that targets IL-6 and STAT1 for the treatment of pain associated with the comorbidity of TMD and FMS.

Ginkgetin exhibits antifibrotic effects by inducing hepatic stellate cell apoptosis via STAT1 activation

Liver fibrosis affects approximately 800 million patients worldwide, with over 2 million deaths each year. Nevertheless, there are no approved medications for treating liver fibrosis. In this study, we investigated the impacts of ginkgetin on liver fibrosis and the underlying mechanisms. The impacts of ginkgetin on liver fibrosis were assessed in mouse models induced by thioacetamide or bile duct ligation. Experiments on human LX-2 cells and primary mouse hepatic stellate cells (HSCs) were performed to explore the underlying mechanisms, which were also validated in the mouse models. Ginkgetin significantly decreased hepatic extracellular matrix deposition and HSC activation in the fibrotic models induced by thioacetamide (TAA) and bile duct ligation (BDL). Beneficial effects also existed in inhibiting hepatic inflammation and improving liver function. In vitro experiments showed that ginkgetin markedly inhibited HSC viability and induced HSC apoptosis dose-dependently. Mechanistic studies revealed that the antifibrotic effects of ginkgetin depend on STAT1 activation, as the effects were abolished in vitro after STAT1 silencing and in vivo after inhibiting STAT1 activation by fludarabine. Moreover, we observed a meaningful cross-talk between HSCs and hepatocytes, in which IL-6, released by ginkgetin-induced apoptotic HSCs, enhanced hepatocyte proliferation by activating STAT3 signaling. Ginkgetin exhibits antifibrotic effects by inducing HSC apoptosis via STAT1 activation and enhances hepatocyte proliferation secondary to HSC apoptosis via the IL-6/STAT3 pathway.

STAT expression and TFH1 cells in CVID granulomatosis and sarcoidosis: immunological and histopathological comparisons

Granulomatous disease is a serious complication of common variable immunodeficiency (CVID-GD) that occurs in 8-22% of these patients and can mimic sarcoidosis, with which it shares certain clinical, biological, and radiological features. However, few studies to date have compared the two pathologies immunologically and histologically. Therefore, we analyzed the immunological-histological findings for different tissue samples from ten patients with CVID-GD and compared them to those of biopsy-proven sarcoidosis. Specifically, we wanted to know whether or not the signaling abnormalities observed in sarcoidosis granulomas are also present in CVID-GD. Morphological differences were found between CVID-GD histology and classical sarcoidosis: mainly, the former's notable lymphoid hyperplasia associated with granulomas not observed in the latter. All CVID-GD involved organs contained several follicular helper-T (TFH) cells within the granulomatosis, while those cells were inconstantly and more weakly expressed in sarcoidosis. Moreover, CVID and sarcoidosis granulomas expressed the phosphorylated-signal transducer and activator of transcription (pSTAT)1 and pSTAT3 factors, regardless of the organ studied and without any significant difference between entities. Our results suggest that the macrophage-activation mechanism in CVID resembles that of sarcoidosis, thereby suggesting that Janus kinase (JAK)-STAT-pathway blockade might be useful in currently difficult-to-treat CVID-GD.

The effect of STAT1, miR-99b, and MAP2K1 in alcoholic liver disease (ALD) mouse model and hepatocyte

Alcoholic liver disease (ALD) serves as the leading cause of chronic liver diseases-related morbidity and mortality, which threatens the life of millions of patients in the world. However, the molecular mechanisms underlying ALD progression remain unclear. Here, we applied microarray analysis and experimental approaches to identify miRNAs and related regulatory signaling that associated with ALD. Microarray analysis identified that the expression of miR-99b was elevated in the ALD mouse model. The AML-12 cells were treated with EtOH and the expression of miR-99b was enhanced in the cells. The expression of miR-99b was positively correlated with ALT levels in the ALD mice. The microarray analysis identified the abnormally expressed mRNAs in ALD mice and the overlap analysis was performed with based on the differently expressed mRNAs and the transcriptional factors of miR-99b, in which STAT1 was identified. The elevated expression of STAT1 was validated in ALD mice. Meanwhile, the treatment of EtOH induced the expression of STAT1 in the AML-12 cells. The expression of STAT1 was positively correlated with ALT levels in the ALD mice. The positive correlation of STAT1 and miR-99b expression was identified in bioinformatics analysis and ALD mice. The expression of miR-99b and pri-miR-99b was promoted by the overexpression of STAT1 in AML-12 cells. ChIP analysis confirmed the enrichment of STAT1 on miR-99b promoter in AML-12 cells. Next, we found that the expression of mitogen-activated protein kinase kinase 1 (MAP2K1) was negatively associated with miR-99b. The expression of MAP2K1 was downregulated in ALD mice. Consistently, the expression of MAP2K1 was reduced by the treatment of EtOH in AML-12 cells. The expression of MAP2K1 was negative correlated with ALT levels in the ALD mice. We identified the binding site of MAP2K1 and miR-99b. Meanwhile, the treatment of miR-99b mimic repressed the luciferase activity of MAP2K1 in AML-12 cells. The expression of MAP2K1 was suppressed by miR-99b in the cells. We observed that the expression of MAP2K1 was inhibited by the overexpression of STAT1 in AML-12 cells. Meanwhile, the apoptosis of AML-12 cells was induced by the treatment of EtOH, while miR-99b mimic promoted but the overexpression of MAP2K1 attenuated the effect of EtOH in the cells. In conclusion, we identified the correlation and effect of STAT1, miR-99b, and MAP2K1 in ALD mouse model and hepatocyte. STAT1, miR-99b, and MAP2K1 may serve as potential therapeutic target of ALD.

LATS1/2 loss promote tumor immune evasion in endometrial cancer through downregulating MHC-I expression

BACKGROUND

LATS1/2 are frequently mutated and down-regulated in endometrial cancer (EC), but the contributions of LATS1/2 in EC progression remains unclear. Impaired antigen presentation due to mutations or downregulation of the major histocompatibility complex class I (MHC-I) has been implicated in tumor immune evasion. Herein, we elucidate the oncogenic role that dysregulation of LATS1/2 in EC leads to immune evasion through the down-regulation of MHC-I.

METHODS

The mutation and expression as well as the clinical significance of LATS1/2 in EC was assessed in the TCGA cohort and our sample cohort. CRISPR-Cas9 was used to construct knockout cell lines of LATS1/2 in EC. Differentially expressed genes were analyzed by RNA-seq. The interaction between LATS1/2 and STAT1 was verified using co-immunoprecipitation and GST pull-down assays. Mass spectrometry, in vitro kinase assays, ChIP-qPCR, flow cytometry, immunohistochemistry, immunofluorescence and confocal microscopy were performed to investigate the regulation of LATS1/2 on MHC-I through interaction with and phosphorylate STAT1. The killing effect of activated PBMCs on EC cells were used to monitor anti-tumor activity.

RESULTS

Here, we demonstrate that LATS1/2 are frequently mutated and down-regulated in EC. Moreover, LATS1/2 loss was found to be associated with a significant down-regulation of MHC-I, independently of the Hippo-YAP pathway. Instead, LATS1/2 were found to directly interact with and phosphorylate STAT1 at Ser727, a crucial transcription factor for MHC-I upregulation in response to interferon-gamma (IFN-γ) signaling, to promote STAT1 accumulating and moving into the nucleus to enhance the transcriptional activation of IRF1/NLRC5 on MHC-I. Additionally, the loss of LATS1/2 was observed to confer increased resistance of EC cells to immune cell-mediated killing and this resistance could be reversed by over-expression of MHC-I.

CONCLUSION

Our findings indicate that dysregulation of LATS1/2 in EC leads to immune evasion through the down-regulation of MHC-I, leading to the suppression of infiltrating activated CD8 + T cells and highlight the importance of LATS1/2 in IFN-γ signaling-mediated tumor immune response, suggesting that LATS1/2 is a promising target for immune checkpoint blockade therapy in EC.

Enterovirus D68 3C protease antagonizes type I interferon signaling by cleaving signal transducer and activator of transcription 1

Following the successful control of poliovirus, the re-emergence of respiratory enterovirus D68 (EV-D68), a prominent non-polio enterovirus, has become a serious public health concern worldwide. Host innate immune responses are the primary defense against EV-D68 invasion; however, the mechanism underlying viral evasion of the antiviral activity of interferons (IFN) remains unclear. In this study, we found that EV-D68 inhibited type I IFN signaling by cleaving signal transducer and activator of transcription 1 (STAT1), a crucial factor in cellular responses to interferons and other cytokines. We observed that the prototype and circulating EV-D68 strains conserved their ability to induce STAT1 cleavage and attenuate IFN signal transduction. Further investigation revealed that EV-D68 3C protease cleaves STAT1 at the 131Q residue. Interestingly, not all enterovirus-encoded 3C proteases exhibited this ability. EV-D68 and poliovirus 3C proteases efficiently induced STAT1 cleavage; whereas, 3C proteases from EV-A71, coxsackievirus A16, and echoviruses did not. STAT1 cleavage also abolished the nuclear translocation capacity of STAT1 in response to IFN stimulation to activate downstream signaling elements. Overall, these results suggest that STAT1, targeted by viral protease 3C, is utilized by EV-D68 to subvert the host's innate immune response.IMPORTANCEEnterovirus D68 (EV-D68) has significantly transformed over the past decade, evolving from a rare pathogen to a potential pandemic pathogen. The interferon (IFN) signaling pathway is an important defense mechanism and therapeutic target for the host to resist viral invasion. Previous studies have reported that the EV-D68 virus blocks or weakens immune recognition and IFN production in host cells through diverse strategies; however, the mechanisms of EV-D68 resistance to IFN signaling have not been fully elucidated. Our study revealed that EV-D68 relies on its own encoded protease, 3C, to directly cleave signal transducer and activator of transcription 1 (STAT1), a pivotal transduction component in the IFN signaling pathway, disrupting the IFN-mediated antiviral response. Previous studies on human enteroviruses have not documented direct cleavage of the STAT1 protein to evade cellular immune defenses. However, not all enteroviral 3C proteins can cleave STAT1. These findings highlight the diverse evolutionary strategies different human enteroviruses employ to evade host immunity.

Hypidone hydrochloride (YL-0919) protects mice from meningitis via Sigma1R-STAT1-NLRP3-GSDMD pathway

BACKGROUND

A growing number of studies have found that antidepressants have anti-inflammatory effects while protecting nerves. Hypidone hydrochloride (YL-0919) is a novel highly selective 5-HT reuptake blocker. Our previous studies have demonstrated that YL-0919 exerts notable antidepressant- and anxiolytic-like as well as procognitive effects. However, whether YL-0919 can be used to treat inflammatory and infectious diseases remain unknown. In this study, we aimed to verify the anti-inflammatory effect of YL-0919 on bacterial meningitis and further explore the potential molecular mechanisms.

METHODS

We performed the experiments on pneumococcal meningitis mice in vivo and S. pneumoniae infected macrophages/microglia in vitro, with or without YL-0919 treatment. Cognitive function was evaluated by open-field task, Morris water maze test, and novel object recognition test. Histopathological staining and immunofluorescence staining were used to detect the pathological damage of meningitis and NLRP3 inflammasome activation in microglia/macrophages. The expression of the STAT1/NLRP3/GSDMD signal pathway was measured by western blots. Proinflammatory cytokines associated with pyroptosis were detected by ELISA.

RESULTS

YL-0919 protected mice from fatal pneumococcal meningitis, characterized by attenuated cytokine storms, decreased bacterial loads, improved neuroethology, and reduced mortality. NLRP3 plays a key role in the regulation of inflammation. When the underlying mechanisms were investigated, we found that YL-0919 inhibited the activation of NLRP3 via STAT1, and thus inhibited macrophages/microglia pyroptosis, resulting in downregulation of proinflammatory cytokines. In addition, Sigma1R was identified as a pivotal receptor that can be engaged by YL-0919 to inhibit NLRP3 activation and pyroptosis pathway in microglia/macrophages.

CONCLUSIONS

These results provide new insights into the mechanisms of inflammation regulation mediated by the antidepressant YL-0919. Moreover, targeting the STAT1/NLRP3 pyroptosis pathway is a promising strategy for the treatment of infectious diseases like bacterial meningitis.

Low-Shear Stress Promotes Atherosclerosis via Inducing Endothelial Cell Pyroptosis Mediated by IKKε/STAT1/NLRP3 Pathway

Atherosclerosis is initiated by vascular endothelial dysfunction, and low-shear stress (LSS) of blood flow is a key factor leading to endothelial dysfunction. Growing evidence suggests that endothelial cell pyroptosis plays an important role in the development of atherosclerosis. Studies have shown that low-shear stress can induce endothelial cell pyroptosis, but the exact mechanism remains unclear. Our experiments demonstrated that low-shear stress induced endothelial cell pyroptosis and the phosphorylation of IκB kinase ε (IKKε). IKKε knockdown not only significantly attenuated atherosclerosis lesions of aortic arch areas in ApoE-/- mice fed with high cholesterol diets, but also markedly reduced endothelial cell pyroptosis and NLRP3 expression triggered by low-shear stress. Further mechanism studies showed that IKKε promoted the expression of NLRP3 via activating signal transducer and activator of transcription 1 (STAT1) and the subsequent binding of STAT1 to NLRP3 promoter region. These results suggest that low-shear stress plays a pro-atherosclerotic role by promoting endothelial cell pyroptosis through the IKKε/STAT1/NLRP3 pathway, which provides new insights into the formation of atherosclerosis.

Toxoplasma gondii IST suppresses inflammatory and apoptotic responses by inhibiting STAT1-mediated signaling in IFN-γ/TNF-α-stimulated hepatocytes

The dense granule protein of Toxoplasma gondii, inhibitor of signal transducer and activator of transcription 1 (IST) is an inhibitor of signal transducer and activator of transcription 1 (STAT1) transcriptional activity that binds to STAT1 and regulates the expression of inflammatory molecules in host cells. A sterile inflammatory liver injury in pathological acute liver failures occurs when excessive innate immune function, such as the massive release of IFN-γ and TNF-α, is activated without infection. In relation to inflammatory liver injury, we hypothesized that Toxoplasma gondii inhibitor of STAT1 transcription (TgIST) can inhibit the inflammatory response induced by activating the STAT1/IRF-1 mechanism in liver inflammation. This study used IFN-γ and TNF-α as inflammatory inducers at the cellular level of murine hepatocytes (Hepa-1c1c7) to determine whether TgIST inhibits the STAT1/IRF-1 axis. In stable cells transfected with TgIST, STAT1 expression decreased with a decrease in interferon regulatory factor (IRF)-1 levels. Furthermore, STAT1 inhibition of TgIST resulted in lower levels of NF-κB and COX2, as well as significantly lower levels of class II transactivator (CIITA), iNOS, and chemokines (CLXCL9/10/11). TgIST also significantly reduced the expression of hepatocyte proapoptotic markers (Caspase3/8/9, P53, and BAX), which are linked to sterile inflammatory liver injury. TgIST also reduced the expression of adhesion (ICAM-1 and VCAM-1) and infiltration markers of programmed death-ligand 1 (PD-L1) induced by hepatocyte and tissue damage. TgIST restored the cell apoptosis induced by IFN-γ/TNF-α stimulation. These results suggest that TgIST can inhibit STAT1-mediated inflammatory and apoptotic responses in hepatocytes stimulated with proinflammatory cytokines.

Photobiomodulation with 630-nm LED Inhibits M1 Macrophage Polarization via STAT1 Pathway Against Sepsis-Induced Acute Lung Injury

Background: Sepsis-induced acute lung injury (ALI) is a clinical syndrome characterized by excessive uncontrolled inflammation. Photobiomodulation such as light-emitting diode (LED) irradiation has been used to attenuate inflammatory disease. Objective: The protective effect of 630 nm LED irradiation on sepsis-induced ALI remains unknown. The purpose of this study was to investigate the role of 630 nm LED irradiation in sepsis-induced ALI and its underlying mechanism. Methods and results: C57BL/6 mice were performed cecal ligation and puncture (CLP) for 12 h to generate experimental sepsis models. Histopathology analysis showed that alveolar injury, inflammatory cells infiltration, and hemorrhage were suppressed in CLP mice after 630 nm LED irradiation. The ratio of wet/dry weigh of lung tissue was significantly inhibited by irradiation. The number of leukocytes was reduced in bronchoalveolar lavage fluid. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) results and enzyme-linked immunosorbent assay showed that 630 nm LED irradiation significantly inhibited the mRNA and protein levels of M1 macrophage-related genes in the lung of CLP-induced septic mice. Meanwhile, LED irradiation significantly inhibited signal transducer and activator of transcription 1 (STAT1) phosphorylation in the lung of septic mice. In vitro experiments showed that 630 nm LED irradiation significantly inhibited M1 genes mRNA and protein expression in THP-1-derived M1 macrophages without affecting the cell viability. LED irradiation also significantly inhibited the level of STAT1 phosphorylation in THP-1-derived M1 macrophages. Conclusions: We concluded that 630 nm LED is promising as a treatment against ALI through inhibiting M1 macrophage polarization, which is associated with the downregulation of STAT1 phosphorylation.

Avian coronavirus infectious bronchitis virus Beaudette strain NSP9 interacts with STAT1 and inhibits its phosphorylation to facilitate viral replication

Avian coronavirus, known as infectious bronchitis virus (IBV), is the causative agent of infectious bronchitis (IB). Viral nonstructural proteins play important roles in viral replication and immune modulation. IBV NSP9 is a component of the RNA replication complex for viral replication. In this study, we uncovered a function of NSP9 in immune regulation. First, the host proteins that interacted with NSP9 were screened. The immune-related protein signal transducer and activator of transcription 1 (STAT1) was identified and the interaction between NSP9 and STAT1 was further confirmed. Furthermore, IBV replication was inhibited in STAT1-overexpressing cells but inversely affected in STAT1 knock-down cells. Importantly, NSP9 inhibited STAT1 phosphorylation. Finally, the expression of JAK/STAT pathway downstream genes IRF7 and ISG20 was significantly decreased in NSP9-overexpressing cells. These results showed the important role of IBV NSP9 in immunosuppression.

3'-Sialyllactose protects against LPS-induced endothelial dysfunction by inhibiting superoxide-mediated ERK1/2/STAT1 activation and HMGB1/RAGE axis

AIM

Endothelial hyperpermeability is an early stage of endothelial dysfunction associated with the progression and development of atherosclerosis. 3'-Sialyllactose (3'-SL) is the most abundant compound in human milk oligosaccharides, and it has the potential to regulate endothelial dysfunction. This study investigated the beneficial effects of 3'-SL on lipopolysaccharide (LPS)-induced endothelial dysfunction in vitro and in vivo.

MAIN METHODS

We established LPS-induced endothelial dysfunction models in both cultured bovine aortic endothelial cells (BAECs) and mouse models to determine the effects of 3'-SL. Western blotting, qRT-PCR analysis, immunofluorescence staining, and en face staining were employed to clarify underlying mechanisms. Superoxide production was measured by 2',7'-dichlorofluorescin diacetate, and dihydroethidium staining.

KEY FINDINGS

LPS significantly decreased cell viability, whereas 3'-SL treatment mitigated these effects via inhibiting ERK1/2 activation. Mechanistically, 3'-SL ameliorated LPS-induced ROS accumulation leading to ERK1/2 activation-mediated STAT1 phosphorylation and subsequent inhibition of downstream transcriptional target genes, including VCAM-1, TNF-α, IL-1β, and MCP-1. Interestingly, LPS-induced ERK1/2/STAT1 activation leads to the HMGB1 release from the nucleus into the extracellular space, where it binds to RAGE, while 3'-SL suppressed EC hyperpermeability by suppressing the HMGB1/RAGE axis. This interaction also led to VE-cadherin endothelial junction disassembly and endothelial cell monolayer disruption through ERK1/2/STAT1 modulation. In mouse endothelium, en face staining revealed that 3'-SL abolished LPS-stimulated ROS production and VCAM-1 overexpression.

SIGNIFICANCE

Our findings suggest that 3'-SL inhibits LPS-induced endothelial hyperpermeability by suppressing superoxide-mediated ERK1/2/STAT1 activation and HMGB1/RAGE axis. Therefore, 3'-SL may be a potential therapeutic agent for preventing the progression of atherosclerosis.

NSD2 modulates Drp1-mediated mitochondrial fission in chronic renal allograft interstitial fibrosis by methylating STAT1

Renal interstitial fibrosis/tubular atrophy (IF/TA) is a prominent pathological feature of chronic allograft dysfunction (CAD). Our previous study has demonstrated that epithelial-mesenchymal transition (EMT) plays a significant role in shaping the development of IF/TA. Nuclear SET domain (NSD2), a histone methyltransferase catalyzing methylation at lysine 36 of histone 3, is crucially involved in the development and progression of solid tumors. But its role in the development of renal allograft interstitial fibrosis has yet to be elucidated. Here, we characterize NSD2 as a crucial mediator in the mouse renal transplantation model in vivo and a model of tumor necrosis factor-α (TNF-α) stimulated-human renal tubular epithelial cells (HK-2) in vitro. Functionally, NSD2 knockdown inhibits EMT, dynamin-related protein 1 (Drp1)-mediated mitochondrial fission in mice. Conversely, NSD2 overexpression exacerbates fibrosis-associated phenotypes and mitochondrial fission in tubular cells. Mechanistically, tubular NSD2 aggravated the Drp-1 mediated mitochondrial fission via STAT1/ERK/PI3K/Akt signaling pathway in TNF-α-induced epithelial cell models. Momentously, mass spectrometry (MS) Analysis and site-directed mutagenesis assays revealed that NSD2 interacted with and induced Mono-methylation of STAT1 on K173, leading to its phosphorylation, IMB1-dependent nuclear translocation and subsequent influence on TNF-α-induced EMT and mitochondrial fission in NSD2-dependent manner. Collectively, these findings shed light on the mechanisms and suggest that targeting NSD2 could be a promising therapeutic approach to enhance tubular cell survival and alleviate interstitial fibrosis in renal allografts during CAD.

Angiotensin converting enzyme 2 does not facilitate porcine epidemic diarrhea virus entry into porcine intestinal epithelial cells and inhibits it-induced inflammatory injury by promoting STAT1 phosphorylation

ACE2 has been confirmed to be a functional receptor for SARS-CoV and SARS-CoV-2, but research on animal coronaviruses, especially PEDV, are still unknown. The present study investigated whether ACE2 plays a role in receptor recognition and subsequent infection during PEDV invasion of host cells. IPEC-J2 cells stably expressing porcine ACE2 did not increase the production of PEDV-N but inhibited its expression. Porcine ACE2 knockout cells was generated by CRISPR/Cas9 genome editing in IPEC-J2 cells. The expression of PEDV-N did not decrease but slightly increased. The Co-IP results showed that there was no significant association between ACE2 and PEDV-S. There were no obvious interaction between PEDV-S, PEDV-E, PEDV-M and porcine ACE2 promoters, but PEDV-N could inhibit the activity of ACE2 promoters. PEDV-N degraded STAT1 and prevented its phosphorylation, thereby inhibiting the expression of interferon-stimulated genes. Repeated infection of PEDV further confirmed the above results. PEDV activated ACE-Ang II-AT1R axis, while ACE2-Ang (1-7)-MasR axis activity was decreased and inflammatory response was intensified. However, excess ACE2 can reverse this reaction. These results reveal that ACE2 does not facilitate PEDV entry into cells, but relieves PEDV-induced inflammation by promoting STAT1 phosphorylation.

Rescue of NLRC5 expression restores antigen processing machinery in head and neck cancer cells lacking functional STAT1 and p53

The antigen processing machinery (APM) components needed for a tumor cell to present an antigen to a T cell are expressed at low levels in solid tumors, constituting an important mechanism of immune escape. More than most other solid tumors, head and neck squamous cell carcinoma (HNSCC) cells tend to have low APM expression, rendering them insensitive to immune checkpoint blockade and most other forms of immunotherapy. In HNSCC, this APM deficiency is largely driven by high levels of EGFR and SHP2, leading to low expression and activation of STAT1; however, recent studies suggest that p53, which is often mutated in HNSCCs, may also play a role. In the current study, we aimed to investigate the extent to which STAT1 and p53 individually regulate APM component expression in HNSCC cells. We found that in cells lacking functional p53, APM expression could still be induced by interferon-gamma or DNA-damaging chemotherapy (cisplatin) as long as STAT1 expression remained intact; when both transcription factors were knocked down, APM component expression was abolished. When we bypassed these deficient pathways by rescuing the expression of NLRC5, APM expression was also restored. These results suggest that dual loss of functional STAT1 and p53 may render HNSCC cells incapable of processing and presenting antigens, but rescue of downstream NLRC5 expression may be an attractive strategy for restoring sensitivity to T cell-based immunotherapy.

Transforming Growth Factor Beta 2 (TGFB2) and Interferon Gamma Receptor 2 (IFNGR2) mRNA Levels in the Brainstem Tumor Microenvironment (TME) Significantly Impact Overall Survival in Pediatric DMG Patients

This hypothesis-generating study characterized the mRNA expression profiles and prognostic impacts of antigen-presenting cell (APC) markers (CD14, CD163, CD86, and ITGAX/CD11c) in pediatric brainstem diffuse midline glioma (pbDMG) tumors. We also assessed the mRNA levels of two therapeutic targets, transforming growth factor beta 2 (TGFB2) and interferon gamma receptor 2 (IFNGR2), for their biomarker potentials in these highly aggressive pbDMG tumors. The expressions of CD14, CD163, and ITGAX/CD11c mRNAs exhibited significant decreases of 1.64-fold (p = 0.037), 1.75-fold (p = 0.019), and 3.33-fold (p < 0.0001), respectively, in pbDMG tumors relative to those in normal brainstem/pons samples. The pbDMG samples with high levels of TGFB2 in combination with low levels of APC markers, reflecting the cold immune state of pbDMG tumors, exhibited significantly worse overall survival outcomes at low expression levels of CD14, CD163, and CD86. The expression levels of IFNGR2 and TGFB2 (1.51-fold increase (p = 0.002) and 1.58-fold increase (p = 5.5 × 10-4), respectively) were significantly upregulated in pbDMG tumors compared with normal brainstem/pons samples. We performed multivariate Cox proportional hazards modelling that showed TGFB2 was a prognostic indicator (HR for patients in the TGFB2high group of pbDMG patients = 2.88 (1.12-7.39); p = 0.028) for poor overall survival (OS) and was independent of IFNGR2 levels, the age of the patient, and the significant interaction effect observed between IFNGR2 and TGFB2 (p = 0.015). Worse survival outcomes in pbDMG patients when comparing high versus low TGFB2 levels in the context of low IFNGR2 levels suggest that the abrogation of the TGFB2 mRNA expression in the immunologically cold tumor microenvironment can be used to treat pbDMG patients. Furthermore, pbDMG patients with low levels of JAK1 or STAT1 mRNA expression in combination with high levels of TGFB2 also exhibited poor OS outcomes, suggesting that the inclusion of (interferon-gamma) IFN-γ to stimulate and activate JAK1 and STAT1 in anti-tumor APC cells present the brainstem TME can enhance the effect of the TGFB2 blockade.

Zika virus infection triggers caspase cleavage of STAT1

IMPORTANCE

Zika virus (ZIKV) is a re-emerging flavivirus. Similar to other flaviviruses, ZIKV antagonizes the host interferon (IFN) signaling pathway to establish infection. Understanding the molecular mechanism by which ZIKV antagonizes IFN-induced antiviral signaling may lead to a new antiviral strategy by cracking the IFN antagonism. Flaviviruses have been reported to employ NS5-dependent and -independent mechanisms to block STAT2-mediated signaling, whereas whether flaviviruses target STAT1 remains controversial. Herein, we found that ZIKV infection triggered caspase-dependent cleavage of STAT1 at the aspartic acid 694 during late infection, whereas murine STAT1 (mSTAT1) was resistant to cleavage. Intriguingly, ectopically expressed cleavage-resistant human STAT1.D694A or complementation of cleavable mSTAT1.D695G exerted comparable anti-ZIKV activity with their counterparts, challenging the role of caspase-mediated STAT1 cleavage in the IFN antagonism in ZIKV-infected cells. These data may also imply a dominant role of the antagonism of STAT2 but not STAT1 in ZIKV-infected cells.

Role of ATG7-dependent non-autophagic pathway in angiogenesis

ATG7, one of the core proteins of autophagy, plays an important role in various biological processes, including the regulation of autophagy. While clear that autophagy drives angiogenesis, the role of ATG7 in angiogenesis remains less defined. Several studies have linked ATG7 with angiogenesis, which has long been underappreciated. The knockdown of ATG7 gene in cerebrovascular development leads to angiogenesis defects. In addition, specific knockout of ATG7 in endothelial cells results in abnormal development of neovascularization. Notably, the autophagy pathway is not necessary for ATG7 regulation of angiogenesis, while the ATG7-dependent non-autophagic pathway plays a critical role in the regulation of neovascularization. In order to gain a better understanding of the non-autophagic pathway-mediated biological functions of the autophagy-associated protein ATG7 and to bring attention to this expanding but understudied research area, this article reviews recent developments in the ATG7-dependent non-autophagic pathways regulating angiogenesis.

PKR inhibitor protects spinal cord injury through mitigating endoplasmic reticulum stress and pyroptosis

OBJECTIVES

The goal of the study was to reveal the regulatory role of protein kinase R (PKR) in spinal cord injury (SCI), a devasting disorder of the neurological system, and to elucidate its potential mechanism.

METHODS

The established animal and cellular models of SCI were treated by the PKR inhibitor C12. Histological injury and tissue apoptosis were assessed via H&E staining and TUNEL assays, respectively. Basso-Beattie-Bresnahan (BBB) scoring as well as forelimb grip strength tests were employed to evaluate functional recovery. The production of ROS and cytokines were appraised via their related commercial kits. Western blot and immunofluorescence assay were used to examine protein expression. CCK-8 method was used to assay cell activity. Co-immunoprecipitation assay was conducted to measure the affinity of PKR with STAT1.

RESULTS

PKR expression was enhanced following SCI, and the PKR inhibitor C16 mitigated histological injury, cell apoptosis and water content in spinal cord, and improved function recovery following SCI. Meanwhile, C16 attenuated ER stress, pyroptosis, NLRP3 inflammasome and inflammation in mice with SCI and in BV-2 cells challenged with LPS. Additionally, PKR interacted with STAT1 in BV-2 cells, and STAT1 knockdown inhibited ER stress, pyroptosis and inflammation in BV-2 cells challenged with LPS. The protective role of C16 in BV-2 cells exposed to LPS were partly abolished by STAT1 overexpression.

CONCLUSION

PKR inhibition might be a prospective effective approach to attenuating SCI and accelerating function recovery through modulating microglial pyroptosis and ER stress.

Exosome-derived miR-5p-72106_14 in vascular endothelial cells regulates fate determination of BMSCs

Vascular endothelial cells have recently been shown to be associated with osteogenic activity. However, the mechanism of vascular endothelial cells promoting osteogenesis is unclear. Here, we found that exosomes secreted from human microvascular endothelial cells (HMEC-1) promoted osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and inhibited adipogenic differentiation. Aged and ovariectomy mice treated with exosomes showed increased bone formation and decreased lipid accumulation in the bone marrow cavity. Additionally, we screened out novel exosomal miR-5p-72106_14 by miRNA-seq and confirmed that miR-5p-72106_14 promoted osteogenic differentiation and inhibited adipogenic differentiation of BMSCs by inhibiting STAT1. Our results suggest that vascular endothelial cell-derived exosomes are involved in BMSC differentiation and exosomal miR-5p-72106_14 is a major factor in regulating fate determination of BMSCs.

Antibody dependent cell-mediated cytotoxicity selection pressure induces diverse mechanisms of resistance

Targeted monoclonal antibody therapy has emerged as a powerful therapeutic strategy for cancer. However, only a minority of patients have durable responses and the development of resistance remains a major clinical obstacle. Antibody-dependent cell-mediated cytotoxicity (ADCC) represents a crucial therapeutic mechanism of action; however, few studies have explored ADCC resistance. Using multiple in vitro models of ADCC selection pressure, we have uncovered both shared and distinct resistance mechanisms. Persistent ADCC selection pressure yielded ADCC-resistant cells that are characterized by a loss of NK cell conjugation and this shared resistance phenotype is associated with cell-line dependent modulation of cell surface proteins that contribute to immune synapse formation and NK cell function. We employed single-cell RNA sequencing and proteomic screens to interrogate molecular mechanisms of resistance. We demonstrate that ADCC resistance involves upregulation of interferon/STAT1 and DNA damage response signaling as well as activation of the immunoproteasome. Here, we identify pathways that modulate ADCC sensitivity and report strategies to enhance ADCC-mediated elimination of cancer cells. ADCC resistance could not be reversed with combinatorial treatment approaches. Hence, our findings indicate that tumor cells utilize multiple strategies to inhibit NK cell mediated-ADCC. Future research and development of NK cell-based immunotherapies must incorporate plans to address or potentially prevent the induction of resistance.

RanBP2/Nup358 Mediates Sumoylation of STAT1 and Antagonizes Interferon-α-Mediated Antiviral Innate Immunity

Type I interferon (IFN-I)-induced signaling plays a critical role in host antiviral innate immune responses. Despite this, the mechanisms that regulate this signaling pathway have yet to be fully elucidated. The nucleoporin Ran Binding Protein 2 (RanBP2) (also known as Nucleoporin 358 KDa, Nup358) has been implicated in a number of cellular processes, including host innate immune signaling pathways, and is known to influence viral infection. In this study, we documented that RanBP2 mediates the sumoylation of signal transducers and activators of transcription 1 (STAT1) and inhibits IFN-α-induced signaling. Specifically, we found that RanBP2-mediated sumoylation inhibits the interaction of STAT1 and Janus kinase 1 (JAK1), as well as the phosphorylation and nuclear accumulation of STAT1 after IFN-α stimulation, thereby antagonizing the IFN-α-mediated antiviral innate immune signaling pathway and promoting viral infection. Our findings not only provide insights into a novel function of RanBP2 in antiviral innate immunity but may also contribute to the development of new antiviral therapeutic strategies.

Signal Transducer and Activator of Transcription Proteins at the Nexus of Immunodeficiency, Autoimmunity and Cancer

The signal transducer and activator of transcription (STAT) family of proteins has been demonstrated to perform pivotal roles downstream of a myriad of cytokines, particularly those that control immune cell production and function. This is highlighted by both gain-of-function (GOF) and loss-of-function (LOF) mutations being implicated in various diseases impacting cells of the immune system. These mutations are typically inherited, although somatic GOF mutations are commonly observed in certain immune cell malignancies. This review details the growing appreciation of STAT proteins as a key node linking immunodeficiency, autoimmunity and cancer.

Nickel-induced transcriptional memory in lung epithelial cells promotes interferon signaling upon nicotine exposure

Exposure to nickel, an environmental respiratory toxicant, is associated with lung diseases including asthma, pulmonary fibrosis, bronchitis and cancers. Our previous studies have shown that a majority of the nickel-induced transcriptional changes are persistent and do not reverse even after the termination of exposure. This suggested transcriptional memory, wherein the cell 'remembers' past nickel exposure. Transcriptional memory, due to which the cells respond more robustly to a previously encountered stimulus has been identified in a number of organisms. Therefore, transcriptional memory has been described as an adaptive mechanism. However, transcriptional memory caused by environmental toxicant exposures has not been well investigated. Moreover, how the transcriptional memory caused by an environmental toxicant might influence the outcome of exposure to a second toxicant has not been explored. In this study, we investigated whether nickel-induced transcriptional memory influences the outcome of the cell's response to a second respiratory toxicant, nicotine. Nicotine, an addictive compound in tobacco, is associated with the development of chronic lung diseases including chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis. Our results show that nicotine exposure upregulated a subset of genes only in the cells previously exposed to nickel. Furthermore, our analyses indicate robust activation of interferon (IFN) signaling in these cells. IFN signaling is a driver of inflammation, which is associated with many chronic lung diseases. Therefore, our results suggest that nicotine exposure of lung cells that retain the transcriptional memory of previous nickel exposure could result in increased susceptibility to developing chronic inflammatory lung diseases.

TGF-β-p-STAT1-LAIR2 axis has a "self-rescue" role for exhausted CD8+ T cells in hepatocellular carcinoma

BACKGROUND

TGF-β is related to the function of T cells in the tumor microenvironment. However, the characteristics of TGF-β affecting the function of CD8+ T cells in hepatocellular carcinoma (HCC) have not been clearly resolved.

METHODS

In this study, flow cytometry, mass cytometry, immunohistochemistry, RNA-seq, single-cell RNA-seq, assay for transposase-accessible chromatin with high throughput sequencing, chromatin immunoprecipitation, and dual-luciferase reporter gene assay were used to study the regulatory effect and molecular mechanism of TGF-β on HCC infiltrating CD8+ T cells.

RESULTS

Here, we demonstrated that the overall effect of TGF-β on CD8+ T cells in HCC was to activate p-p38 to induce exhaustion, but it also initiated cell-intrinsic resistance mechanisms: 1) TGF-β upregulated the levels of p-STAT1 (S727) and promoted LAIR2 secretion; 2) the TGF-β-p-STAT1-LAIR2 axis relieved CD8+ T cells from exhaustion, which we called "self-rescue"; 3) this "self-rescue" behavior showed time and dose limitations on TGF-β stimulation, which was easily masked by stronger inhibitory signals; 4) the function of CD8+ T cells was improved by using TAK-981 to amplify "self-rescue" signal.

CONCLUSION

Our study describes a "self-rescue" mechanism of CD8+ T cells in HCC against exhaustion and the good effects from amplifying this signal.

Lactate inhibits interferon-α response in ovarian cancer by inducing STAT1 ubiquitin degradation

The emergence of lactate, produced by lactate dehydrogenase A (LDHA), as an important regulator of the immune response in tumor development has garnered attention in recent research. But, many questions still need to be clarified regarding the relationship between lactate and anti-tumor immunity. Here, we reported that both exogenous and endogenous lactate reduced the protein level and activation of the signal transducer and activator of transcription 1(STAT1) in ovarian cancer cells. As a consequence, the expression of IFNα-STAT1 regulated genes was weakened. This, in turn, weakened the antitumor effect of IFNα by impeding NKT and CD8+T cells recruitment. Strikingly, we found that LDHA knockdown did not result in the downregulation of STAT1 mRNA level in ovarian cancer cells. Instead, we observed that lactate triggered the degradation of STAT1 through the proteasomal pathway. Notably, we identified that lactate reduced the stability of STAT1 by promoting the expression of F-box only protein 40 (Fbxo40). This protein interacts with STAT1 and potentially acts as an E3 ubiquitin ligase, leading to the induction of STAT1 polyubiquitination and degradation. Importantly, ectopic over-expression of the Fbxo40 gene significantly inhibited the expression of ISGs in LDHA knockdown cells. In the TCGA tumor data, we observed that high expression of Fbxo40 negatively correlates with overall survival in ovarian cancer patients. Collectively, our findings reveal lactate as a negative regulator of the IFNα-STAT1 signaling axis in ovarian cancer. This discovery suggests that strategies aimed at targeting lactate for ovarian cancer prevention and treatment should consider the impact on the IFNα-STAT1 response.

Insulin-like growth factor 2 mRNA-binding protein 2 is a therapeutic target in ovarian cancer

Ovarian cancer (OC) is a fatal gynecologic disease. The most common treatment for OC patients is surgery combined with chemotherapy but most patients at advanced stages eventually develop relapse due to chemoresistance. This study examined the role and function of insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) in OC. We observed that the expression of IGF2BP2 mRNA and protein was up-regulated in OC cells and tissues using quantitative real-time polymerase chain reaction (qRT-PCR) and western blot, respectively. An increase in IGF2BP2 expression at mRNA and protein levels was verified by the analyses of The Cancer Genome Atlas (TCGA) and Clinical Proteomic Tumor Analysis Consortium (CPTAC), respectively. Gene Expression Omnibus (GEO) and Cancer Cell Line Encyclopedia (CCLE) databases were applied to analyze the expression and clinical value of IGF2BP2. Gene set enrichment analysis (GSEA), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Ontology (GO) analyses explored biological functions and the involvement of IGF2BP2 in cell growth. Indeed, the knockdown of IGF2BP2 resulted in the inhibition of OC cell proliferation evaluated by the Cell Counting Kit-8 assay. Genomic amplification of IGF2BP2 partly accounted for its overexpression. High expression of IGF2BP2 was associated with signal transducer and activator of transcription 1 (STAT1) and drug sensitivity and was correlated with an unfavorable survival outcome in OC patients. Furthermore, the responsiveness of chemotherapy and immunotherapy were analyzed using the "pRRophetic" R package and The Cancer Immune Atlas (TCIA) database, respectively. The low expression of IGF2BP2 was associated with chemoresistance but with high tumor microenvironment scores and tumor-infiltrating immune cells, suggesting that immunotherapy may apply in chemoresistant patients. The alteration of IGF2BP2 expression may respond to chemotherapy and immunotherapy. Thus, IGF2BP2 shows potential as a therapeutic target and diagnostic biomarker for OC.

Acetyltransferases CBP/p300 Control Transcriptional Switch of β-Catenin and Stat1 Promoting Osteoblast Differentiation

CREB-binding protein (CBP) (CREBBP) and p300 (EP300) are multifunctional histone acetyltransferases (HATs) with extensive homology. Germline mutations of CBP or p300 cause skeletal abnormalities in humans and mice. However, the precise roles of CBP/p300 in bone homeostasis remain elusive. Here, we report that conditional knockout of CBP or p300 in osteoblasts results in reduced bone mass and strength due to suppressed bone formation. The HAT activity is further confirmed to be responsible for CBP/p300-mediated osteogenesis using A-485, a selective inhibitor of CBP/p300 HAT. Mechanistically, CBP/p300 HAT governs osteogenic gene expression in part through transcriptional activation of β-catenin and inhibition of Stat1. Furthermore, acetylation of histone H3K27 and the transcription factor Foxo1 are demonstrated to be involved in CBP/p300 HAT-regulated β-catenin and Stat1 transcription, respectively. Taken together, these data identify acetyltransferases CBP/p300 as critical regulators that promote osteoblast differentiation and reveal an epigenetic mechanism responsible for maintaining bone homeostasis. © 2023 American Society for Bone and Mineral Research (ASBMR).

ETS2 overexpression ameliorates cartilage injury in osteoarthritis by the ETS2/miR-155/STAT1/DNMT1 feedback loop pathway

Osteoarthritis (OA) is the most common irreversible chronic joint dysfunction disease, which is pathologically characterized by disturbance of articular cartilage homeostasis leading to subsequent inflammatory response and cartilage extracellular matrix (ECM) degradation. Increasing evidence has demonstrated the dysregulation of transcription factors play crucial roles in the occurrence and development of osteoarthritis (OA), but the potential functions and mechanism of most transcription factors in OA has not been completely illuminated. In this study, we identified that transcription factor V-ets erythroblastosis virus E26 oncogene homolog 2 (ETS2) was significantly down-regulated in OA cartilage and IL-1β-induced OA chondrocytes. Functional experiments in vitro demonstrated that the overexpressed ETS2 strikingly enhanced proliferation, outstandingly suppressed apoptosis, and dramatically reduced inflammation and ECM degradation in IL-1β-induced OA chondrocytes, whereas the knockdown of ETS2 led to the opposite effects. Further in vivo studies have shown that up-regulated ETS2 dramatically ameliorates cartilage injury in DMM-induced OA mice. Mechanical studies have disclosed that DNMT1-mediated downregulation of ETS2 dramatically promotes STAT1 by inhibiting miR-155 transcription, and increased STAT1 initiates a feedback loop that may enhance DNMT1-mediated hypermethylation of ETS2 to inhibit ETS2 expression, thus forming a DNMT1/ETS2/miR-155/STAT1 feedback loop that inhibits MAPK signaling pathways and aggravates OA cartilage injury. In all, our results revealed that overexpression of ETS2 markedly ameliorated OA cartilage injury through the ETS2/miR-155/STAT1/DNMT1 feedback loop, providing a new perspective on the pathogenesis and therapeutic strategies for OA.

The effect of an exopolysaccharide probiotic molecule from Bacillus subtilis on breast cancer cells

Introduction

Many well-known risk factors for breast cancer are associated with dysbiosis (an aberrant microbiome). However, how bacterial products modulate cancer are poorly understood. In this study, we investigated the effect of an exopolysaccharide (EPS) produced by the commensal bacterium Bacillus subtilis on breast cancer phenotypes. Although B. subtilis is commonly included in probiotic preparations and its EPS protects against inflammatory diseases, it was virtually unknown whether B. subtilis-derived EPS affects cancer.

Methods

This work investigated effects of EPS on phenotypes of breast cancer cells as a cancer model. The phenotypes included proliferation, mammosphere formation, cell migration, and tumor growth in two immune compromised mouse models. RNA sequencing was performed on RNA from four breast cancer cells treated with PBS or EPS. IKKβ or STAT1 signaling was assessed using pharmacologic or RNAi-mediated knock down approaches.

Results

Short-term treatment with EPS inhibited proliferation of certain breast cancer cells (T47D, MDA-MB-468, HCC1428, MDA-MB-453) while having little effect on others (MCF-7, MDA-MB-231, BT549, ZR-75-30). EPS induced G1/G0 cell cycle arrest of T47D cells while increasing apoptosis of MDA-MB-468 cells. EPS also enhanced aggressive phenotypes in T47D cells including cell migration and cancer stem cell survival. Long-term treatment with EPS (months) led to resistance in vitro and promoted tumor growth in immunocompromised mice. RNA-sequence analysis showed that EPS increased expression of pro-inflammatory pathways including STAT1 and NF-κB. IKKβ and/or STAT1 signaling was necessary for EPS to modulate phenotypes of EPS sensitive breast cancer cells.

Discussion

These results demonstrate a multifaceted role for an EPS molecule secreted by the probiotic bacterium B. subtilis on breast cancer cell phenotypes. These results warrant future studies in immune competent mice and different cancer models to fully understand potential benefits and/or side effects of long-term use of probiotics.