The transcription factor E74-like factor 4 suppresses differentiation of proliferating CD4+ T cells to the Th17 lineage

ELF4 was a prognostic biomarker and related to immune infiltrates in glioma

ELF4 (E74-like factor 4) is a transcription factor, dysregulation of which has been associated with carcinogenesis and cancer development. Nevertheless, the precise role of ELF4 in glioma pathology and its impact on clinical outcomes remains to be investigated. In the present research, comprehensive analyses demonstrated that elevated expression of ELF4 in glioma tissues correlates with malignant phenotypes and adverse clinical outcomes. Multivariate Cox regression analysis determined that ELF4 expression could serve as a reliable predictor of glioma outcomes. (CGGA, hazard ratio [HR]: 1.21, 95% confidence interval [CI]: 1.09-1.34, p<0.001; TCGA, HR: 1.19, 95%CI: 1.01-1.41, p=0.043; and Gravendeel, HR: 1.44, 95%CI: 1.15-1.80, p=0.002). Knockdown of ELF4 reduced the cell viability and migration capacity of glioma cells in vitro. In addition to the tumor invasive role, enrichment analysis revealed the overexpressed ELF4 was involved in the immune regulation, characterized by the elevated activity of Il6/Jak/Stat3 signaling, interferon alpha (IFN-α) response, and IL2/Stat5 signaling. Single-cell RNA sequencing (scRNA)-seq and spatial transcriptome (ST)-seq analyses revealed that ELF4 could induce reprogramming of tumor-associated monocytes/macrophages (TAMMs). Molecular docking analysis revealed ELF4 might be targeted by drugs/compounds, including Veliparib (ABT-888), Motesanib (AMG 706), and EHT 1864. Genomic analysis revealed that, in LGG, in the low ELF4 expression subgroup, IDH1 demonstrated a higher mutation rate, and TP53 and ATRX Chromatin Remodeler (ATRX) displayed the lower mutation rates, than the high ELF4 expression group. Conclusion: Our research suggests that ELF4 may contribute to the prognostic assessment of glioma and personalized medicine.

A Novel Frameshift Variant of the ELF4 Gene in a Patient with Autoinflammatory Disease: Clinical Features, Transcriptomic Profiling and Functional Studies

We described the diagnosis and treatment of a patient with autoinflammatory disease, named "Deficiency in ELF4, X-linked (DEX)". A novel ELF4 variant was discovered and its pathogenic mechanism was elucidated. The data about clinical, laboratory and endoscopic features, treatment, and follow-up of a patient with DEX were analyzed. Whole exome sequencing and Sanger sequencing were performed to identify potential pathogenic variants. The mRNA and protein levels of ELF4 were analyzed by qPCR and Western blotting, respectively. The association of ELF4 frameshift variant with nonsense-mediated mRNA decay (NMD) in the pathogenesis DEX was examined. Moreover, RNA-seq was performed to identify the key molecular events triggered by ELF4 variant. The relationship between ELF4 and IFN-β activity was validated using a dual-luciferase reporter assay and a ChIP-qPCR assay. An 11-year-old boy presented with a Behçet's-like phenotype. The laboratory abnormality was the most obvious in elevated inflammatory indicators. Endoscopy revealed multiple ileocecal ulcers. Intestinal histopathology showed inflammatory cell infiltrations. The patient was treated with long-term immunosuppressant and TNF-α blocker (adalimumab), which reaped an excellent response over 16 months of follow-up. Genetic analysis identified a maternal hemizygote frameshift variant (c.1022del, p.Q341Rfs*30) in ELF4 gene in the proband. The novel variant decreased the mRNA level of ELF4 via the NMD pathway. Mechanistically, insufficient expression of ELF4 disturbed the immune system, leading to immunological disorders and pathogen susceptibility, and disrupted ELF4-activating IFN-β responses. This analysis detailed the clinical characteristics of a Chinese patient with DEX who harbored a novel ELF4 frameshift variant. For the first time, we used patient-derived cells and carried out transcriptomic analysis to delve into the mechanism of ELF4 variant in DEX.

[Two Cases of Behcet's Disease-Like Syndrome with Gene Deficiency in ELF4]

The patient 1, a 13-year-old boy, was admitted due to "recurrent oral ulcers for 3 years, abdominal pain for 8 months, and perianal ulcers for 10 days"; The patient 2, a 3-year-old boy, was admitted due to "recurrent abdominal pain, diarrhea, and fever for over 3 months". Genetic testing of both patients revealed "deficiency in ELF4, X-linked" (DEX), and the patients were diagnosed with Behcet's disease-like syndrome due to deficiency in ELF4, accordingly. The patient 1 was successively given intravenous methylprednisolone pulses and oral prednisone and mesalazine for symptomatic treatment. The patient 2 was successively treated with corticosteroids combined with enteral nutrition, as well as oral mercaptopurine. Subsequently, both patients showed improvements in symptoms and were discharged.

Current understanding of ELF4 deficiency: a novel inborn error of immunity

BACKGROUND

ELF4 deficiency has been recently recognized as a novel disorder within the spectrum of inborn errors of immunity (IEIs), specifically categorized as a "disease of immune dysregulation." Cases of this condition, reported by our team and others, are very limited worldwide. As such, our current knowledge of this new disease remains preliminary. This review aims to provide a brief overview of the clinical manifestations, pathogenesis, and treatment strategies for this novel IEI.

DATA SOURCES

A comprehensive review was conducted after an extensive literature search in the PubMed/Medline database and websites concerning transcriptional factor ELF4 and reports concerning patients with ELF4 deficiency. Our search strategy was "ELF4 OR ETS-related transcription factor Elf-4 OR EL4-like factor 4 OR myeloid Elf-1-like factor" as of the time of manuscript submission.

RESULTS

The current signature manifestations of ELF4 deficiency disorder are recurrent and prolonged oral ulcer, abdominal pain, and diarrhea in pediatric males. In some cases, immunodeficiency and autoimmunity can also be prominent. Targeted Sanger sequencing or whole exome sequencing can be used to detect variation in ELF4 gene. Western blotting for ELF4 expression of the patient's cells can confirm the pathogenic effect of the variant. To fully confirm the pathogenicity of the variant, further functional test is strongly advised. Glucocorticoid and biologics are the mainstream management of ELF4 deficiency disorder.

CONCLUSIONS

Pediatric males presenting with recurring ulcerations in digestive tract epithelium with or without recurrent fever should be suspected of DEX. When atypical presentations are prominent, variations in ELF4 gene should be carefully evaluated functionally due to the complex nature of ELF4 function. Experience of treating DEX includes use of glucocorticoid and biologics and more precise treatment needs more patients to identify and further mechanistic study.

"Deficiency in ELF4, X-Linked": a Monogenic Disease Entity Resembling Behçet's Syndrome and Inflammatory Bowel Disease

Defining monogenic drivers of autoinflammatory syndromes elucidates mechanisms of disease in patients with these inborn errors of immunity and can facilitate targeted therapeutic interventions. Here, we describe a cohort of patients with a Behçet's- and inflammatory bowel disease (IBD)-like disorder termed "deficiency in ELF4, X-linked" (DEX) affecting males with loss-of-function variants in the ELF4 transcription factor gene located on the X chromosome. An international cohort of fourteen DEX patients was assessed to identify unifying clinical manifestations and diagnostic criteria as well as collate findings informing therapeutic responses. DEX patients exhibit a heterogeneous clinical phenotype including weight loss, oral and gastrointestinal aphthous ulcers, fevers, skin inflammation, gastrointestinal symptoms, arthritis, arthralgia, and myalgia, with findings of increased inflammatory markers, anemia, neutrophilic leukocytosis, thrombocytosis, intermittently low natural killer and class-switched memory B cells, and increased inflammatory cytokines in the serum. Patients have been predominantly treated with anti-inflammatory agents, with the majority of DEX patients treated with biologics targeting TNFα.

The transcription factor ELF4 alleviates inflammatory bowel disease by activating IL1RN transcription, suppressing inflammatory TH17 cell activity, and inducing macrophage M2 polarization

Background

Inflammatory bowel disease (IBD) is a chronic immune-mediated disorder affecting millions worldwide. Due to the complexity of its pathogenesis, the treatment options for IBD are limited. This study focuses on ELF4, a member of the ETS transcription factor family, as a target to elucidate its role in IBD and investigate its mechanism of action in alleviating IBD symptoms by activating IL1RN transcription to suppress the activity of inflammatory TH17 cells.

Methods

Using the GEO database, this study examined LPS-induced intestinal inflammatory genes and their regulation mechanisms. We examined the colon length of LPS-treated mice and derived the Disease Activity Index (DAI). H&E staining, ELISA, and flow cytometry were used to detect mice colon tissue damage, inflammatory factor levels in mouse serum, mouse macrophage types and inflammatory TH17 cell activity. RT-qPCR and Western blot detected ELF4, IL1RN, M1, and M2 polarization markers. In Vitro, using dual-luciferase and ChIP assays, we tested mouse bone marrow-derived macrophages (BMDMs) and mouse intestinal epithelial cells for IL1RN promoter activity and ELF4 enrichment.

Results

Bioinformatics showed that LPS-induced colitis animals have reduced ELF4 expression in their colon tissue. In vivo tests confirmed reduced ELF4 expression in mice with LPS-induced colitis. ELF4 overexpression reduced mouse intestinal inflammation. ELF4 activated IL1RN transcription in bioinformatics and in vitro tests. ELF4 promoted IL1RN transcription and macrophage M2 polarization to limit intestinal epithelial cell death and inflammation and reduce mouse intestinal inflammation in vitro. ELF4 also reduced the Th17/Treg ratio by increasing IL1RN transcription.

Conclusion

ELF4 activates IL1RN transcription, suppresses inflammatory TH17 cells, and induces macrophage M2 polarization to treat IBD.

Knockdown of ELF4 aggravates renal injury in ischemia/reperfusion mice through promotion of pyroptosis, inflammation, oxidative stress, and endoplasmic reticulum stress

BACKGROUND

Renal ischemia/reperfusion (I/R) injury is a major cause of acute kidney injury (AKI). Dysfunction of E74-like ETS transcription factor 4 (ELF4) leads to inflammation. This research intended to look into the function and mechanisms of ELF4 in I/R and oxygen-glucose deprivation/reperfusion (OGD/R) model.

RESULTS

In I/R and OGD/R model, ELF4 expression was downregulated. ELF4 knockout aggravated I/R-induced kidney injury, oxidative stress (OS), endoplasmic reticulum stress (ERS), apoptosis, inflammation, and pyroptosis in mice. In HK-2 cells treated with OGD/R, suppression of ELF4 expression inhibited cell proliferation and promoted cell apoptosis, OS, ERS, inflammation, and pyroptosis. Moreover, ELF4 overexpression led to the opposite results.

CONCLUSION

ELF4 deficiency aggravated I/R induced AKI, which was involved in apoptosis, OS, ERS, inflammation, and pyroptosis. Targeting ELF4 may be a promising new therapeutic strategy for preventing inflammation after IR-AKI.

In vitro treatment of murine splenocytes with extracellular vesicles derived from mesenchymal stem cells altered the mRNA levels of the master regulator genes of T helper cell subsets

INTRODUCTION

The purpose of the current study was to evaluate the effect of mesenchymal stem cells-derived extracellular vesicles (MSC-EVs) on the production of cytokines and expression of genes, which are corresponded to the subsets of T helper cells.

MATERIALS AND METHODS

The supernatant of the second passage of MSCs that had been isolated from C57BL/6 mice abdominal adipose tissue was used to collect the MSC-EV. Splenocytes of healthy mice were activated using anti-CD3 and anti-CD28 antibodies and simultaneously were treated using the MSC-EVs. The proliferation rate of lymphocytes and the frequency of regulatory T cells were measured using flow cytometry. In addition, the expressions of T helper cell subset-specific transcription factors were evaluated using a real-time PCR assay. To appraise the effects of MSC-EV on splenocytes, the levels of IFN-γ, IL-17A, IL-10, and TGF-β were measured using ELISA.

RESULTS

The results showed that the treatment of the CD3/CD28-activated splenocytes with MSC-EV did not statistically change the proliferation of CD3⁺ splenocytes. However, after the treatment, the mRNA levels of Foxp3 and Elf4 as well as the frequency of regulatory T cells was significantly higher when compared to the control group. The expression levels of Gata3, Rorc, and Tbx21 were down-regulated while, the corresponding cytokines levels did not alter.

CONCLUSION

The results revealed that the in vitro treatment of MSC-EV was associated with the increase in the frequency of CD4⁺CD25⁺FOXP3⁺ T cells and upregulation of Foxp3 mRNA level.

X-linked genetic risk factors that promote autoimmunity and dampen remyelination are associated with multiple sclerosis susceptibility

BACKGROUND

Multiple sclerosis (MS) is a chronic neurodegenerative disease, which has a strong genetic component and is more prevalent in women. MS is caused by an autoimmunity initiated inflammatory response which leads to axon demyelination, followed by axon loss, plaque formation and neurodegeneration. The goal of this article was to explore X-linked genetic factors that are associated with MS susceptibility.

METHODS

Using UK Biobank microarray, we analyzed the prevalence of alleles on the X chromosome to identify variants potentially involved in MS. Overall, 488,225 patients across 18,857 markers were analyzed using PLINK.

RESULTS

Our results identify 20 SNPs that are significantly more abundant in persons with MS. The genes associated with these SNPs belong to immunity (LAMP2, AVPR2, MTMR8, F8, BCOR, PORCN, and ELF4) and remyelination (NSDHL, HS6ST2, RBM10, TAZ, and AR) pathways that are potentially of great significance for understanding the onset and progression of multiple sclerosis. We further identified a significant 20-fold increase in incidence of MS cases in women with co-occurrences of SNPs associated with myelination and immunity functions.

CONCLUSIONS

Our analysis provides novel insights into the roles of X-linked genes in the onset and presentation of multiple sclerosis, identifying 20 SNPs in 14 genes involved primarily in immunity and myelination functions that are significantly more abundant in persons with MS. Our co-occurrence analysis suggests that concurrent disruption of both myelination and immune systems significantly increases the risk of MS onset in women.

Proximal and Distal Regions of Pathogenic Th17 Related Chromatin Loci Are Sequentially Accessible During Pathogenicity of Th17

Pathogenic Th17, featured by their production of pro-inflammatory cytokines, are considered as a key player in most autoimmune diseases. The transcriptome of them is obviously distinct from that of conventional regulatory Th17. However, chromatin accessibility of the two Th17 groups have not been comprehensively compared yet. Here, we found that their chromatin-accessible regions(ChARs) significantly correlated with the expression of related genes, indicating that they might engage in the regulation of these genes. Indeed, pathogenic Th17 specific ChARs (patho-ChARs) exhibited a significant distribution preference in TSS-proximal region. We further filtered the patho-ChARs based on their conservation among mammalians or their concordance with the expression of their related genes. In either situation, the filtered patho-ChARs also showed a preference for TSS-proximal region. Enrichment of expression concordant patho-ChARs related genes suggested that they might involve in the pathogenicity of Th17. Thus, we also examined all ChARs of patho-ChARs related genes, and defined an opening ChAR set according to their changes in the Th17 to Th1 conversion. Interestingly, these opening ChARs displayed a sequential accessibility change from TSS-proximal region to TSS-distal region. Meanwhile, a group of patho-TFs (transcription factors) were identified based on the appearance of their binding motifs in the opening ChARs. Consistently, some of them also displayed a similar preference for binding the TSS-proximal region. Single-cell transcriptome analysis further confirmed that these patho-TFs were involved in the generation of pathogenic Th17. Therefore, our results shed light on a new regulatory mechanism underlying the generation of pathogenic Th17, which is worth to be considered for autoimmune disease therapy.

Loss of Function Mutation in ELF4 Causes Autoinflammatory and Immunodeficiency Disease in Human

Monogenic autoinflammatory diseases (mAIDs) are a heterogeneous group of diseases affecting primarily innate immunity, with various genetic causes. Genetic diagnosis of mAIDs can assist in the patient's management and therapy. However, a large number of sporadic and familial cases remain genetically uncharacterized. Deficiency in ELF4, X-linked (DEX) is recently identified as a novel mAID. Here, we described a pediatric patient suffering from recurrent viral and bacterial respiratory infection, refractory oral ulcer, constipation, and arthritis. Whole-exome sequencing found a hemizygous variant in ELF4 (chrX:129205133 A > G, c.691 T > C, p.W231R). Using cells from patient and point mutation mice, we showed mutant cells failed to restrict viral replication effectively and produced more pro-inflammatory cytokines. RNA-seq identified several potential critical antiviral and anti-inflammation genes with decreased expression, and ChIP-qPCR assay suggested mutant ELF4 failed to bind to the promoters of these genes. Thus, we presented the second report of DEX.

Immune Response of an Oral Enterococcus faecalis Phage Cocktail in a Mouse Model of Ethanol-Induced Liver Disease

Cytolysin-positive Enterococcus faecalis (E. faecalis) cause more severe alcohol-associated hepatitis, and phages might be used to specifically target these bacteria in a clinical trial. Using a humanized mouse model of ethanol-induced liver disease, the effect of cytolytic E. faecalis phage treatment on the intestinal and liver immune response was evaluated. The observed immune response was predominantly anti-inflammatory and tissue-restoring. Besides, live phages could be readily recovered from the serum, spleen, and liver following oral gavage in ethanol-fed mice. We also isolated 20 new phages from the sewage water; six of them exhibited a relatively broad host range. Taken together, the oral administration of cytolytic E. faecalis phages leads to the translocation of phages to the systemic circulation and appears to be safe, following chronic-binge ethanol administration. A cocktail of three phages covers the majority of tested cytolysin-positive E. faecalis strains and could be tested in a clinical trial.

Human autoinflammatory disease reveals ELF4 as a transcriptional regulator of inflammation

Transcription factors specialized to limit the destructive potential of inflammatory immune cells remain ill-defined. We discovered loss-of-function variants in the X-linked ETS transcription factor gene ELF4 in multiple unrelated male patients with early onset mucosal autoinflammation and inflammatory bowel disease (IBD) characteristics, including fevers and ulcers that responded to interleukin-1 (IL-1), tumor necrosis factor or IL-12p40 blockade. Using cells from patients and newly generated mouse models, we uncovered ELF4-mutant macrophages having hyperinflammatory responses to a range of innate stimuli. In mouse macrophages, Elf4 both sustained the expression of anti-inflammatory genes, such as Il1rn, and limited the upregulation of inflammation amplifiers, including S100A8, Lcn2, Trem1 and neutrophil chemoattractants. Blockade of Trem1 reversed inflammation and intestine pathology after in vivo lipopolysaccharide challenge in mice carrying patient-derived variants in Elf4. Thus, ELF4 restrains inflammation and protects against mucosal disease, a discovery with broad translational relevance for human inflammatory disorders such as IBD.

Elf4 regulates lysosomal biogenesis and the mTOR pathway to promote clearance of Staphylococcus aureus in macrophages

Staphylococcus aureus is a major cause of infectious disease. Macrophages can directly destroy most of the invading bacteria through the phagolysosomal pathway. E74-like factor 4 (Elf4) is one of the important transcription factors that controls diverse pathogens, but the role of Elf4 in macrophage-mediated S. aureus eradication is unknown. Our data show that Elf4 is induced by S. aureus in macrophages. Elevated expression of Elf4 results in decreased bacterial load and inflammatory responses during S. aureus infection in vivo and in vitro. Elf4-overexpressed macrophages have decreased mTOR activity and increased lysosomal mass. Collectively, these results suggest that S. aureus induces Elf4 expression, which enhances lysosomal function and increases the capacity of macrophages to eliminate intracellular pathogens.

Suppression of ELF4 in ulcerative colitis predisposes host to colorectal cancer

Ulcerative colitis (UC) is a chronic inflammatory bowel disease, characterized by relapsing and remitting colon mucosal inflammation. For patients suffering from UC, a higher risk of colon cancer has been widely recognized. Here, we found that Elf4^−/− mice developed colon tumors with 3 cycles of dextran sulfate sodium salt (DSS) treatment alone. We further showed that ELF4 suppression was prevalent in both patients with UC and DSS-induced mice models, and this suppression was caused by promoter region methylation. ELF4, upon PARylation by PARP1, transcriptionally regulated multiple DNA damage repair machinery components. Consistently, ELF4 deficiency leads to more severe DNA damage both in vitro and in vivo. Oral administration of montmorillonite powder can prevent the reduction of ELF4 in DSS-induced colitis models and lower the risk of colon tumor development during azoxymethane (AOM) and DSS induced colitis-associated cancer (CAC). These data provided additional mechanism of CAC initiation and supported the “epigenetic priming model of tumor initiation”.

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Elf4 expression is suppressed in both colitis and colitis-associated cancer (CAC).

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Elf4 deficiency leads to increased hyper-susceptibility to colitis and CAC in mice

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Elf4 promotes DNA damage repair upon PARylation by PARP1

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Oral administration of montmorillonite lowers risk of CAC development

Immunosuppressive Effects of Mesenchymal Stem Cells-derived Exosomes

Mesenchymal stem cells (MSCs) have become important seed cells in therapy because of their immunosuppressive function and anti-inflammatory effects. MSCs exert immunosuppressive effects through direct contact or paracrine action. The paracrine functions of MSCs are at least partially mediated by exosomes, which are membrane vesicles, carrying abundant proteins, nucleic acids and other active molecules. MSC-exos have heterogeneity. The exosomes from different donors, tissues generations of MSCs carry different bioactive molecules. These cargos are transferred to recipient cells by endocytosis or binding to proteins on the receptor surface to mediate intercellular communication between different cell types and affect the functions of the recipient cells. Exosomes play an important role in the regulation of the immune system. Exosomes derived from MSCs (MSC-exos) carry immunomodulatory effectors or transmit active signal molecules to regulate the biological activities of immune cells and thus mediating immune suppression, especially on macrophages and T cells. Mitochondria and autophagy-related pathways are also associated with MSC-exos immunosuppressive effects. Graphical Abstract.

Early life exposures shape the CD4+ T cell transcriptome, influencing proliferation, differentiation, and mitochondrial dynamics later in life

Early life environmental exposures drive lasting changes to the function of the immune system and can contribute to disease later in life. One of the ways environmental factors act is through cellular receptors. The aryl hydrocarbon receptor (AHR) is expressed by immune cells and binds numerous xenobiotics. Early life exposure to chemicals that bind the AHR impairs CD4+ T cell responses to influenza A virus (IAV) infection in adulthood. However, the cellular mechanisms that underlie these durable changes remain poorly defined. Transcriptomic profiling of sorted CD4+ T cells identified changes in genes involved in proliferation, differentiation, and metabolic pathways were associated with triggering AHR during development. Functional bioassays confirmed that CD4+ T cells from infected developmentally exposed offspring exhibit reduced proliferation, differentiation, and cellular metabolism. Thus, developmental AHR activation shapes T cell responsive capacity later in life by affecting integrated cellular pathways, which collectively alter responses later in life. Given that coordinated shifts in T cell metabolism are essential for T cell responses to numerous challenges, and that humans are constantly exposed to many different types of AHR ligands, this has far-reaching implications for how AHR signaling, particularly during development, durably influences T cell mediated immune responses across the lifespan.

In vitro analysis of immunomodulatory effects of mesenchymal stem cell- and tumor cell -derived exosomes on recall antigen-specific responses

BACKGROUND

The aim of the present study was to evaluate in vitro effects of exosomes derived from mesenchymal stem cells (MSCs) or tumor cells on recall-antigen-specific immune responses.

METHODS

The exosomes were isolated from the supernatant of the cultures of the adipose-derived MSCs, and 4T1 cell line. The splenocytes isolated from experimental autoimmune encephalomyelitis (EAE) mice were utilized to evaluate the effects of exosomes on recall-antigen-specific responses. The expression of master regulators for T cell sub-types and the levels of their corresponding cytokines were evaluated.

RESULTS

Treatment by disease-inducing peptide (MOG_35-55) combined with MSC-EXO or by MOG+TEX enhanced the expression of Foxp3 as the master regulator for Treg cells; by comparing with splenocytes which were treated by MOG. Nonetheless, the production of IL-10 and TGF-β were increased only in splenocytes treated by MOG+TEX. Additionally, treatments of splenocytes by MOG+TEX and MOG+MSC-EXO decreased the expression of Tbx21 and Gata3, as the master regulator for T helper (T_H)1 and T_H2 responses. However, the IFN-γ level did not decrease. The expression of Rorc and Elf4, which are the activator and inhibitor for differentiation of T_H17 respectively were increased after splenocytes was treated by MOG+TEX. However, a reduction in Rorc and Elf4 levels was observed when splenocytes were treated by MOG+MSC-EXO. Indeed, the concentration of IL-17 did not alter significantly following the treatment by MOG+exosomes.

CONCLUSION

It was ultimately attained that TEX and MSC-EXO utilized various mechanisms to modulate the recall immune responses. TEX was more potent than MSC-EXO to induce regulatory responses by upregulating the production of Foxp3, IL-10, and TGF-β.

Roles and regulations of the ETS transcription factor ELF4/MEF

Most E26 transformation-specific (ETS) transcription factors are involved in the pathogenesis and progression of cancer. This is in part due to the roles of ETS transcription factors in basic biological processes such as growth, proliferation, and differentiation, and also because of their regulatory functions that have physiological relevance in tumorigenesis, immunity, and basal cellular homoeostasis. A member of the E74-like factor (ELF) subfamily of the ETS transcription factor family—myeloid elf-1-like factor (MEF), designated as ELF4—has been shown to be critically involved in immune response and signalling, osteogenesis, adipogenesis, cancer, and stem cell quiescence. ELF4 carries out these functions as a transcriptional activator or through interactions with its partner proteins. Mutations in ELF4 cause aberrant interactions and induce downstream processes that may lead to diseased cells. Knowing how ELF4 impinges on certain cellular processes and how it is regulated in the cells can lead to a better understanding of the physiological and pathological consequences of modulated ELF4 activity.

The Th17 Lineage: From Barrier Surfaces Homeostasis to Autoimmunity, Cancer, and HIV-1 Pathogenesis

The T helper 17 (Th17) cells represent a subset of CD4+ T-cells with unique effector functions, developmental plasticity, and stem-cell features. Th17 cells bridge innate and adaptive immunity against fungal and bacterial infections at skin and mucosal barrier surfaces. Although Th17 cells have been extensively studied in the context of autoimmunity, their role in various other pathologies is underexplored and remains an area of open investigation. This review summarizes the history of Th17 cell discovery and the current knowledge relative to the beneficial role of Th17 cells in maintaining mucosal immunity homeostasis. We further discuss the concept of Th17 pathogenicity in the context of autoimmunity, cancer, and HIV infection, and we review the most recent discoveries on molecular mechanisms regulating HIV replication/persistence in pathogenic Th17 cells. Finally, we stress the need for novel fundamental research discovery-based Th17-specific therapeutic interventions to treat pathogenic conditions associated with Th17 abnormalities, including HIV infection.

Identification of Transcriptional Regulators of Psoriasis from RNA-Seq Experiments

Psoriasis is a common inflammatory skin disease with complex etiology and chronic progression. To provide novel insights into the molecular mechanisms of regulation of the disease we performed RNA sequencing (RNA-Seq) analysis of 14 pairs of skin samples collected from psoriatic patients. Subsequent pathway analysis and an extraction of transcriptional regulators governing psoriasis-associated pathways was executed using a combination of MetaCore Interactome enrichment tool and cisExpress algorithm, and followed by comparison to a set of previously described psoriasis response elements. A comparative approach has allowed us to identify 42 core transcriptional regulators of the disease associated with inflammation (NFkB, IRF9, JUN, FOS, SRF), activity of T-cells in the psoriatic lesions (STAT6, FOXP3, NFATC2, GATA3, TCF7, RUNX1, etc.), hyperproliferation and migration of keratinocytes (JUN, FOS, NFIB, TFAP2A, TFAP2C), and lipid metabolism (TFAP2, RARA, VDR). After merging the ChIP-seq and RNA-seq data, we conclude that the atypical expression of FOXA1 transcriptional factor is an important player in psoriasis, as it inhibits maturation of naive T cells into this Treg subpopulation (CD4+FOXA1+CD47+CD69+PD-L1(hi)FOXP3-), therefore contributing to the development of psoriatic skin lesions.

Integrated computational approach to the analysis of RNA-seq data reveals new transcriptional regulators of psoriasis

Psoriasis is a common inflammatory skin disease with complex etiology and chronic progression. To provide novel insights into the regulatory molecular mechanisms of the disease, we performed RNA sequencing analysis of 14 pairs of skin samples collected from patients with psoriasis. Subsequent pathway analysis and extraction of the transcriptional regulators governing psoriasis-associated pathways was executed using a combination of the MetaCore Interactome enrichment tool and the cisExpress algorithm, followed by comparison to a set of previously described psoriasis response elements. A comparative approach allowed us to identify 42 core transcriptional regulators of the disease associated with inflammation (NFκB, IRF9, JUN, FOS, SRF), the activity of T cells in psoriatic lesions (STAT6, FOXP3, NFATC2, GATA3, TCF7, RUNX1), the hyperproliferation and migration of keratinocytes (JUN, FOS, NFIB, TFAP2A, TFAP2C) and lipid metabolism (TFAP2, RARA, VDR). In addition to the core regulators, we identified 38 transcription factors previously not associated with the disease that can clarify the pathogenesis of psoriasis. To illustrate these findings, we analyzed the regulatory role of one of the identified transcription factors (TFs), FOXA1. Using ChIP-seq and RNA-seq data, we concluded that the atypical expression of the FOXA1 TF is an important player in the disease as it inhibits the maturation of naive T cells into the (CD4+FOXA1+CD47+CD69+PD-L1(hi)FOXP3-) regulatory T cell subpopulation, therefore contributing to the development of psoriatic skin lesions.

Role of Ets Proteins in Development, Differentiation, and Function of T-Cell Subsets

Through positive selection, double-positive cells in the thymus differentiate into CD4(+) or CD8(+) T single-positive cells that subsequently develop into different types of effective T cells, such as T-helper and cytotoxic T lymphocyte cells, that play distinctive roles in the immune system. Development, differentiation, and function of thymocytes and CD4(+) and CD8(+) T cells are controlled by a multitude of secreted and intracellular factors, ranging from cytokine signaling modules to transcription factors and epigenetic modifiers. Members of the E26 transformation specific (Ets) family of transcription factors, in particular, are potent regulators of these CD4(+) or CD8(+) T-cell processes. In this review, we summarize and discuss the functions and underlying mechanisms of the Ets family members that have been characterized as involved in these processes. Ongoing research of these factors is expected to identify practical applications for the Ets family members as novel therapeutic targets for inflammation-related diseases.

Association of Pneumococcal Carriage and Expression of Foxp3+ Regulatory T Cells and Th17 Cells in the Adenoids of Children

BACKGROUND

Pneumococcal carriage in the nasopharynx is a primary means of transmission and a necessary prerequisite for pneumococcal disease.

OBJECTIVES

We analyzed the relationship between expressions of Foxp3+ regulatory T (Treg) cells and Th17 cells, and pneumococcal carriage in the adenoids of children who were either positive or negative for pneumococci.

METHODS

We collected adenoidal tissue and nasopharyngeal swab samples from children undergoing an adenoidectomy. Adenoidal mononuclear cells were isolated, cultured and then stimulated with culture concentrated supernatant (CCS) obtained from a D39 bacterial strain.

RESULTS

Foxp3+ Treg cells were upregulated and Th17 cells were downregulated in populations of adenoidal mononuclear cells obtained from the pneumococcus-positive group. Following CCS stimulation, the increment in Foxp3+ Treg cells in the pneumococcus-positive group was significantly greater than that in the pneumococcus-negative group, while the increment in Th17 cells was less as compared to that in the pneumococcus-negative group. These results were consistent with variations in levels of Foxp3 mRNA and retinoic acid receptor-related orphan receptor-γt mRNA in adenoidal mononuclear cells. Levels of IL-17A and IL-6 in adenoid tissue were higher in the pneumococcus-negative group, and the levels of TGF-β in adenoid tissue were lower in the pneumococcus-negative group compared to the pneumococcus-positive group. Pneumococcal carriage in children was closely associated with the expressions of Foxp3+ Treg and Th17 cells in the adenoid.

CONCLUSION

Upregulation of Foxp3+ Treg cells might downregulate the production of Th17 cells in the adenoid, resulting in decreased scavenging of Streptococcus pneumoniae and chronic pneumococcal carriage.

Bu-Shen-Yi-Qi formulae suppress chronic airway inflammation and regulate Th17/Treg imbalance in the murine ovalbumin asthma model

ETHNOPHARMACOLOGICAL RELEVANCE

Bu-Shen-Yi-Qi formulae (BSYQF) are frequently used in the treatment of chronic inflammatory diseases in the respiratory system in traditional Chinese medicine (TCM). However, the regulatory effect of BSYQF on T helper 17 (Th17) and regulatory T (Treg) cells in murine ovalbumin (OVA) asthma model remains poorly understood. In the present study, we sought to determine the effect of high-performance liquid chromatography/mass spectrometry (HPLC/MS) standardized BSYQF on chronic airway inflammation and Th17/Treg imbalance in the murine OVA asthma model.

MATERIALS AND METHODS

The murine asthma model was induced by OVA sensitization and challenge and BSYQF was oral administrated. 24h after last OVA exposure, airway hyperresponsiveness (AHR) to methacholine (Mch) was assessed, and inflammatory cell counts and classification in bronchoalveolar lavage fluid (BALF) were analysed. Histopathological evaluation of the lung tissue was performed by hematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) staining. Th17 and Treg associated cytokine levels in serum and BALF as well as transcription factors expression in the lung tissue were measured by ELISA, Bio-Plex and western blot assay. We also analysed the CD4(+)RORγt(+) and CD4(+)Foxp3(+) T cells in BALF and spleen by flow cytometric analysis.

RESULTS

Our results demonstrated that oral administration of BSYQF inhibited the markedly increased AHR and lung inflammation (p<0.05), resulted in a dramatic reduction in total inflammatory cells as well as neutrophils (Neu), lymphocytes (Lym), monocytes (Mon), eosinophils (Eos) and basophils (Bas) of OVA-induced asthmatic mice (p<0.05). Furthermore, BSYQF treatment caused a distinct reduction in IL-6, IL-10 and IL-17A levels in serum (p<0.05), and induced a significant improvement in IL-6 and IL-10 as well as a marked decrease in TGF-β1 and IL-17A levels in BALF of OVA-induced asthmatic mice (p<0.05). Mice in BSYQF treated groups also had decreased RORγt and increased Foxp3 expression in the lung tissue (p<0.05). Flow cytometry analysis revealed that CD4(+)RORγt(+) T cells elevated markedly and CD4(+)Foxp3(+) T cells decreased prominently in BALF and spleen in murine OVA asthma model (p<0.05), and BSYQF and DEX treatment lead to an obvious reduction in CD4(+)RORγt(+) T cells in BALF (p<0.05) but not in spleen. BSYQF and DEX treatment resulted in an obvious elevation in CD4(+)Foxp3(+) T cells in BALF and spleen (p<0.05).

CONCLUSIONS

Collectively, these results demonstrated that BSYQF could suppress chronic airway inflammation and regulate Th17/Treg imbalance by inhibition of Th17 and enhancement of Treg functions in the murine OVA asthma model, which may help to elucidate the underlying regulatory mode of BSYQF on asthma treatment.

Spleen supports a pool of innate-like B cells in white adipose tissue that protects against obesity-associated insulin resistance

Lipid accumulation in obesity triggers a low-grade inflammation that results from an imbalance between pro- and anti-inflammatory components of the immune system and acts as the major underlying mechanism for the development of obesity-associated diseases, notably insulin resistance and type 2 diabetes. Innate-like B cells are a subgroup of B cells that respond to innate signals and modulate inflammatory responses through production of immunomodulatory mediators such as the anti-inflammatory cytokine IL-10. In this study, we examined innate-like B cells in visceral white adipose tissue (VAT) and the relationship of these cells with their counterparts in the peritoneal cavity and spleen during diet-induced obesity (DIO) in mice. We show that a considerable number of innate-like B cells bearing a surface phenotype distinct from the recently identified "adipose natural regulatory B cells" populate VAT of lean animals, and that spleen represents a source for the recruitment of these cells in VAT during DIO. However, demand for these cells in the expanding VAT outpaces their recruitment during DIO, and the obese environment in VAT further impairs their function. We further show that removal of splenic precursors of innate-like B cells through splenectomy exacerbates, whereas supplementation of these cells via adoptive transfer ameliorates, DIO-associated insulin resistance. Additional adoptive transfer experiments pointed toward a dominant role of IL-10 in mediating the protective effects of innate-like B cells against DIO-induced insulin resistance. These findings identify spleen-supplied innate-like B cells in VAT as previously unrecognized players and therapeutic targets for obesity-associated diseases.