Downregulation of Mirlet7 miRNA family promotes Tc17 differentiation and emphysema via de-repression of RORγt.

Environmental air irritants including nanosized carbon black (nCB) can drive systemic inflammation, promoting chronic obstructive pulmonary disease (COPD) and emphysema development. The let-7 microRNA (Mirlet7 miRNA) family is associated with IL-17-driven T cell inflammation, a canonical signature of lung inflammation. Recent evidence suggests the Mirlet7 family is downregulated in patients with COPD, however, whether this repression conveys a functional consequence on emphysema pathology has not been elucidated. Here, we show that overall expression of the Mirlet7 clusters, Mirlet7b/Mirlet7c2 and Mirlet7a1/Mirlet7f1/Mirlet7d, are reduced in the lungs and T cells of smokers with emphysema as well as in mice with cigarette smoke (CS)- or nCB-elicited emphysema. We demonstrate that loss of the Mirlet7b/Mirlet7c2 cluster in T cells predisposed mice to exaggerated CS- or nCB-elicited emphysema. Furthermore, ablation of the Mirlet7b/Mirlet7c2 cluster enhanced CD8+IL17a+ T cells (Tc17) formation in emphysema development in mice. Additionally, transgenic mice overexpressing Mirlet7g in T cells are resistant to Tc17 and CD4+IL17a+ T cells (Th17) development when exposed to nCB. Mechanistically, our findings reveal the master regulator of Tc17/Th17 differentiation, RAR-related orphan receptor gamma t (RORγt), as a direct target of Mirlet7 in T cells. Overall, our findings shed light on the Mirlet7/RORγt axis with Mirlet7 acting as a molecular brake in the generation of Tc17 cells and suggest a novel therapeutic approach for tempering the augmented IL-17-mediated response in emphysema.

Steroid receptor coactivators in Treg and Th17 cell biology and function.

Steroid receptor coactivators (SRCs) are master regulators of transcription that play key roles in human physiology and pathology. SRCs are particularly important for the regulation of the immune system with major roles in lymphocyte fate determination and function, macrophage activity, regulation of nuclear factor κB (NF-κB) transcriptional activity and other immune system biology. The three members of the p160 SRC family comprise a network of immune-regulatory proteins that can function independently or act in synergy with each other, and compensate for - or moderate - the activity of other SRCs. Recent evidence indicates that the SRCs are key participants in governing numerous aspects of CD4+ T cell biology. Here we review findings that establish the SRCs as essential regulators of regulatory T cells (Tregs) and T helper 17 (Th17) cells, with a focus on their crucial roles in Treg immunity in cancer and Treg-Th17 cell phenotypic plasticity.

Thymic gene expression analysis reveals a potential link between HIF-1A and Th17/Treg imbalance in thymoma associated myasthenia gravis.

Myasthenia gravis (MG) is an immune-mediated disease frequently associated with thymic changes. Increased T helper 17 (Th17) cell activity and dysfunctional regulatory T (Treg) cells have been demonstrated in subgroups of MG. On the other hand, hypoxia-inducible factor 1 (HIF-1) has been shown to regulate the Th17/Treg balance by inducing Th17 differentiation while attenuating Treg development. To identify the underlying mechanisms of different thymic pathologies in MG development, we evaluated thymic samples from thymoma-associated myasthenia gravis (TAMG), MG with hyperplasia (TFH-MG) and thymoma without MG (TOMA) patients. Differential gene expression analysis revealed that TAMG and TFH-MG cells are associated with different functional pathways. A higher RORC/FOXP3 ratio provided evidence for Th17/Treg imbalance in TAMG potentially related to increased HIF1A. The hypoxic microenvironment in thymoma may be a driver of TAMG by increasing HIF1A. These findings may lead to new therapeutic approaches targeting HIF1A in the development of TAMG.

IGF-1 Genome-Edited Human MSCs Exhibit Robust Anti-Arthritogenicity in Collagen-Induced Arthritis.

Stem cell therapy stands out as a promising avenue for addressing arthritis treatment. However, its therapeutic efficacy requires further enhancement. In this study, we investigated the anti-arthritogenic potential of human amniotic mesenchymal stem cells (AMM) overexpressing insulin-like growth factor 1 (IGF-1) in a collagen-induced mouse model. The IGF-1 gene was introduced into the genome of AMM through transcription activator-like effector nucleases (TALENs). We assessed the in vitro immunomodulatory properties and in vivo anti-arthritogenic effects of IGF-1-overexpressing AMM (AMM/I). Co-culture of AMM/I with interleukin (IL)-1ß-treated synovial fibroblasts significantly suppressed NF-kB levels. Transplantation of AMM/I into mice with collagen-induced arthritis (CIA) led to significant attenuation of CIA progression. Furthermore, AMM/I administration resulted in the expansion of regulatory T-cell populations and suppression of T-helper-17 cell activation in CIA mice. In addition, AMM/I transplantation led to an increase in proteoglycan expression within cartilage and reduced infiltration by inflammatory cells and also levels of pro-inflammatory factors including cyclooxygenase-2 (COX-2), IL-1ß, NF-kB, and tumor necrosis factor (TNF)-α. In conclusion, our findings suggest that IGF-1 gene-edited human AMM represent a novel alternative therapeutic strategy for the treatment of arthritis.

Differential Response of Human Dendritic Cells upon Stimulation with Encapsulated or Non-Encapsulated Isogenic Strains of Porphyromonas gingivalis.

During periodontitis, the extracellular capsule of Porphyromonas gingivalis favors alveolar bone loss by inducing Th1 and Th17 patterns of lymphocyte response in the infected periodontium. Dendritic cells recognize bacterial antigens and present them to T lymphocytes, defining their activation and polarization. Thus, dendritic cells could be involved in the Th1 and Th17 response induced against the P. gingivalis capsule. Herein, monocyte-derived dendritic cells were obtained from healthy individuals and then stimulated with different encapsulated strains of P. gingivalis or two non-encapsulated isogenic mutants. Dendritic cell differentiation and maturation were analyzed by flow cytometry. The mRNA expression levels for distinct Th1-, Th17-, or T-regulatory-related cytokines and transcription factors, as well as TLR2 and TLR4, were assessed by qPCR. In addition, the production of IL-1ß, IL-6, IL-23, and TNF-α was analyzed by ELISA. The encapsulated strains and non-encapsulated mutants of P. gingivalis induced dendritic cell maturation to a similar extent; however, the pattern of dendritic cell response was different. In particular, the encapsulated strains of P. gingivalis induced higher expression of IRF4 and NOTCH2 and production of IL-1ß, IL-6, IL-23, and TNF-α compared with the non-encapsulated mutants, and thus, they showed an increased capacity to trigger Th1 and Th17-type responses in human dendritic cells.

Genomic deletion of Bcl6 differentially affects conventional dendritic cell subsets and compromises Tfh/Tfr/Th17 cell responses.

Conventional dendritic cells (cDC) play key roles in immune induction, but what drives their heterogeneity and functional specialization is still ill-defined. Here we show that cDC-specific deletion of the transcriptional repressor Bcl6 in mice alters the phenotype and transcriptome of cDC1 and cDC2, while their lineage identity is preserved. Bcl6-deficient cDC1 are diminished in the periphery but maintain their ability to cross-present antigen to CD8+ T cells, confirming general maintenance of this subset. Surprisingly, the absence of Bcl6 in cDC causes a complete loss of Notch2-dependent cDC2 in the spleen and intestinal lamina propria. DC-targeted Bcl6-deficient mice induced fewer T follicular helper cells despite a profound impact on T follicular regulatory cells in response to immunization and mounted diminished Th17 immunity to Citrobacter rodentium in the colon. Our findings establish Bcl6 as an essential transcription factor for subsets of cDC and add to our understanding of the transcriptional landscape underlying cDC heterogeneity.

The Dysregulated IL-23/TH17 Axis in Endometriosis Pathophysiology.

Endometriosis is a chronic inflammatory disease in which endometrial-like tissue grows ectopically, resulting in pelvic pain and infertility. IL-23 is a key contributor in the development and differentiation of TH17 cells, driving TH17 cells toward a pathogenic profile. In a variety of inflammatory and autoimmune disorders, TH17 cells secrete proinflammatory cytokines, including IL-17, contributing to disease pathophysiology. Our studies and others have implicated IL-17 and TH17 cell dysregulation in endometriosis, which is associated with disease severity. In this article, we address whether IL-23-driven TH17 cells contribute to cardinal features of lesion proliferation, vascularization, and inflammation in endometriosis using patient samples, representative cell lines, and our established mouse model of endometriosis. The results indicated dysregulated expression of key genes in the IL-23/TH17 axis in patient ectopic and eutopic endometrial samples and increased IL-23 protein in patient plasma compared with controls. In vitro studies using primary human TH cells determined that rIL-23 mixture treatment increased pathogenic TH17 cell frequency. Similarly, rIL-23 treatment of cell lines (12Z cells, EECCs, HUVECs, and hESCs) representative of the endometriotic lesion microenvironment increased cytokines and growth factors, which play a role in lesion establishment and maintenance. In a syngeneic mouse model of endometriosis, rIL-23 treatment altered numbers of myeloid and T cell subsets in peritoneal fluid and increased giant cells within the lesion. Lesions from rIL-23-treated mice did not reveal significant alterations in proliferation/vascularization, although trends of increased proliferation and vascularization were observed. Collectively, these findings provide insights into the impact of the IL-23/TH17 axis on local immune dysfunction and broadly on endometriosis pathophysiology.

NLRC3 attenuates osteoclastogenesis by limiting TNFα+ Th17 cell response in osteoporosis.

NOD-like receptor family CARD domain containing 3 (NLRC3) is the intracellular protein belonging to NLR (NOD-like receptor) family. NLRC3 can negatively regulate inflammatory signal transduction pathways within the adaptive and innate immunocytes. However, studies need to elucidate the biological role of NLRC3 in bone remodeling. Herein, our study proved that NLRC3 prevents bone loss by inhibiting TNFα+ Th17 cell responses. In osteoporosis, NLRC3 attenuated TNFα+ Th17 cell accumulation in the bone marrow. However, osteoporosis (OP) development was aggravated without affecting bone marrow macrophage (BMM) osteoclastogenesis in NLRC3-deficient ovariectomized (OVX) mice. In this study, we transferred the wild-type and NLRC3-/- CD4+ cells into Rag1-/- mice. Consequently, we evidenced the effects of NLRC3 in CD4+ T cells on inhibiting the accumulation of TNFα + Th17 cells, thus restricting bone loss in the OVX mice. Simultaneously, NLRC3-/- CD4+ T cells promoted the recruitment of osteoclast precursors and inflammatory monocytes into the OVX mouse bone marrow. Mechanism-wise, NLRC3 reduced the secretion of TNFα + Th17 cells of RANKL, MIP1α, and MCP1, depending on the T cells. In addition, NLRC3 negatively regulated the Th17 osteoclastogenesis promoting functions via limiting the NF-κB activation. Collectively, this study appreciated the effect of NLRC3 on modulating bone mass via adaptive immunity depending on CD4+ cells. According to findings of this study, NLRC3 may be the candidate anti-OP therapeutic target. KEY MESSAGES: NLRC3 negatively regulated the Th17 osteoclastogenesis promoting functions via limiting the NF-κB activation. NLRC3 may be the candidate anti-OP therapeutic target.

[The role of microbiota and flavonoids in maintaining the balance of helper and regulatory T-lymphocytes associated with the intestinal immune barrier].

The gastrointestinal tract is a barrier, represented by dynamic and mutually regulating components (microbial, chemical, physical and immune) for the selective penetration of luminal contents into the internal environment. From the point of view of immunologists, even in a physiological condition, the epithelium of the intestinal wall is in a state of mild inflammation, which is explained by the constant invasion of antigens (food, microbial) and, in turn, the constant readiness of the immune system to respond. The purpose of this review was to analyze information about the formation of microbial and immunological barriers, immunological tolerance to microbiota and the possible role of flavonoids in this. Material and methods. The literature search was carried out using PubMed, ResearchGate, Elibrary databases mainly for the last 10 years, using the following keywords: flavonoid, gut microbiome/microbiota, Th17, Treg, RORγt, immunity, segmented filamentous bacteria. Results. During the immune response, a significant role in maintaining the intestinal barrier function is assigned to helper T lymphocytes type 17 (Th17). The intestinal microbiome is a key element in the formation of the immune barrier. Th17 differentiation in the intestine is fully triggered by commensals (apparently, the main role belongs to segmented filamentous bacteria) after weaning and the start of complementary feeding. Pro-inflammatory Th17 effectors in the gut are controlled by anti-inflammatory regulatory T-cells (Treg). In recent years, it has been established that despite the opposing functions of regulatory cells and effector Th17 cells, their differentiation is similar and is characterized by the expression of the common transcription factor RORγt. The main part of the peripheral regulatory lymphocytes of the intestine is a population that stably expresses not only FOXP3, but also RORγt. Flavonoids, which are plant secondary metabolites of the polyphenolic structure, are able to inhibit intracellular kinases and, as a result, influence the activation and implementation of effector functions of immunocompetent cells. Some flavonoids promote RORγt expression and appear to be able to reprogram the effector phenotype of Th17 cells, reducing their pathogenicity. Conclusion. Understanding the interactions between the microbiota, immune cells, and factors involved in their regulation, which are critical for the maintenance of tolerance, may facilitate progress in the prevention and therapeutic approaches to treat immunoinflammatory and autoimmune diseases.

Characterization of Th17 tissue-resident memory cells in non-inflamed intestinal tissue of Crohn's disease patients.

Crohn's disease (CD) is a chronic inflammatory disorder affecting the bowel wall. Tissue-resident memory T (Trm) cells are implicated in CD, yet their characteristics remain unclear. We aimed to investigate the transcriptional profiles and functional characteristics of Trm cells in the small bowel of CD and their interactions with immune cells. Seven patients with CD and four with ulcerative colitis as controls were included. Single-cell RNA sequencing and paired T cell receptor sequencing assessed T cell subsets and transcriptional signatures in lamina propria (LP) and submucosa/muscularis propria-enriched fractions (SM/MP) from small bowel tissue samples. We detected 58,123 T cells grouped into 16 populations, including the CD4+ Trm cells with a Th17 signature and CD8+ Trm clusters. In CD, CD4+ Trm cells with a Th17 signature, termed Th17 Trm, showed significantly increased proportions within both the LP and SM/MP areas. The Th17 Trm cluster demonstrated heightened expression of tissue-residency marker genes (ITGAE, ITGA1, and CXCR6) along with elevated levels of IL17A, IL22, CCR6, and CCL20. The clonal expansion of Th17 Trm cells in CD was accompanied by enhanced transmural dynamic potential, as indicated by significantly higher migration scores. CD-prominent Th17 Trm cells displayed an increased interferon gamma (IFNγ)-related signature possibly linked with STAT1 activation, inducing chemokines (i.e., CXCL10, CXCL8, and CXCL9) in myeloid cells. Our findings underscored the elevated Th17 Trm cells throughout the small bowel in CD, contributing to disease pathogenesis through IFNγ induction and subsequent chemokine production in myeloid cells.

Pathogenic Th17 cell-mediated liver fibrosis contributes to resistance to PD-L1 antibody immunotherapy in hepatocellular carcinoma.

Understanding the mechanisms of resistance of hepatocellular carcinoma (HCC) to targeted therapies and immune checkpoint blockade is critical for the development of new combination therapies and improving patient survival. Here, we found that in HCC, anti-programmed cell death 1 ligand 1 (PD-L1) therapy reduces liver cancer growth, but the tumors eventually become resistant to continued therapy. Experimental analyses shows that the infiltration of pathogenic T helper 17 (pTh17) cells increases in drug-resistant HCC, and pTh17 cells secrete interleukin-17A (IL-17A), which promotes the expression of PD-L1 on the surface of HCC cells and produces resistance to anti-PD-L1 therapy. Anti-IL-17A combined with PD-L1 blockade significantly increased the infiltration of cytotoxic CD8+ T cells expressing high levels of interferon-γ and reduced treatment resistance in HCC. These results support the combination of anti-PD-L1 and anti-IL-17A as a novel strategy to induce effective T cell-mediated anti-tumor immune responses.

Prostaglandin E2 may clinically alleviate dry eye disease by inducing Th17 cell differentiation.

Dry eye (DE) is a multifactorial ocular surface disease characterised by an imbalance in tear homeostasis. The pathogenesis of DE is complex and related to environmental, immunological (e.g., T helper 17 cells) and other factors. However, the DE disease pathogenesis remains unclear, thereby affecting its clinical treatment. This study aimed to explore the mechanism through which prostaglandin E2 (PGE2) affects DE inflammation by regulating Th17. The DE mouse model was established through subcutaneous injection of scopolamine hydrobromide. The tear secretion test and break-up time (BUT) method were used to detect tear secretion and tear film BUT, respectively. Enzyme-linked immunosorbent assay (ELISA) was used to detect the concentrations of PGE2, interleukin (IL)-17, IL-6 and tumour necrosis factor (TNF-α) in tear fluid and those of PGE2 and IL-17 in the serum. RT-qPCR and western blotting were used to test the mRNA and protein expression levels of IL-17 and retinoid-related orphan receptor-γt (RORγt). PGE2 was highly expressed in the DE mouse model. The mRNA and protein levels of IL-17 and the key Th17 transcription factor RORγt were increased in tissues of the DE mice. Moreover, PGE2 promoted tear secretion, reduced the BUT, increased the IL-17 concentration in tears and increased the Th17 cell proportion in DE, whereas the PGE2 receptor inhibitor AH6809 reversed the effects of PGE2 on tear secretion, BUT, and the Th17 cell proportion in draining lymph node (DLN) cells. Taken together, the study findings indicate that PGE2 could induce DE-related symptoms by promoting Th17 differentiation.

Downregulation of circular RNA ETS1 promotes SLE activity and inhibits Treg cell differentiation through miR-1205/FoxP3 molecular axis.

PURPOSE: This study aimed to explore the mechanism by which systemic lupus erythematosus (SLE) activity is promoted through Treg inhibition from the perspective of ceRNA. METHODS: qRT-PCR was used to detect the expressions of circETS1, miR-1205, and FoxP3 in clinical SLE patient samples. Overexpression of circETS1and miR-1205, along with knockdown of miR-1205 and FoxP3 were conducted in CD4+ T cells, while the proliferation of helper T cell 17 (Th17) and regulatory T cell (Treg) was detected. Arescue assay was performed to verify the molecular mechanism of circETS1/miR-1205/Foxp3 mRNA axis in regulating CD4+ T cell differentiation. In the in vivo experiment, the expression of miR-1205 in SLE mice was intervened, and renal function, inflammatory factors, and serum complement were measured. Additionally, Treg/Th17 cell ratio was detected by flow cytometry. RESULTS: In SLE patients, Treg cells were found to decrease, while Th17 cells increased. Transfection with circETS1 overexpression led to CD4+ T cells differentiating into Treg cells, causing an imbalance in the Th17/Treg ratio. Transfection of miR-1205 mimic and si-FoxP3 could reverse the effect of circETS1 overexpression. Moreover, inhibiting the expression of miR-1205 showed therapeutic effects on SLE mice. CONCLUSION: circETS1 inhibits Treg via the miR-1205/FoxP3 axis, thereby promoting SLE activity, which may become a new target for SLE treatment.

Elevated levels of peripheral Th17 cells and Th17-related cytokines in patients with periampullary adenocarcinoma.

AIM: Periampullary adenocarcinoma (PAC) is a malignant tumor originating at the ampulla of Vater, distal common bile duct, head of the pancreas, ampulla and duodenum. The levels of circulating Th17 cells and Th17-related cytokines in patients with PAC remain unreported. Therefore, the aim of this study was to determine the levels of circulating Th17 cells and Th17-related cytokines in patients with PAC. MATERIALS AND METHODS: Flow cytometry was used to measure Th17 cell proportions in PBMCs from 60 PAC patients and 30 healthy controls. Enzyme-linked immunosorbent assay (ELISA) was used to quantify IL-17A and IL-23 levels in serum samples, while quantitative reverse transcription polymerase chain reaction (qRT-PCR) assessed IL-17A mRNA expression and Th17-related transcription factors (RORγt and STAT3) in tissue samples. RESULTS: The findings showed a substantial increase in Th17 cell percentages, elevated concentrations of IL-17A and IL-23, and higher mRNA expression levels of IL-17A, RORγt, and STAT3 in patients with PAC when compared to healthy controls (HCs). CONCLUSION: Th17 cells play an important role in the pathogenesis of PAC and may represent potential therapeutic targets.

Sulforaphane effectively inhibits HBV by altering Treg/Th17 immune balance and the MIF-macrophages polarizing axis in vitro and in vivo.

BACKGROUND: Hepatitis B virus (HBV) infection is a major public health problem. After HBV infection, viral antigens shift the immune balance in favor of viral escape. Sulforaphane (SFN) is a traditional Chinese medicine.It regulates multi-biological activities, including anti-inflammation, anticancer, and antiviral. However, few studies reported that SFN can inhibit HBV infection before. METHODS: An immunocompetent HBV CBA/CaJ mouse model and a co-culture model were used to explore the effect of SFN on HBV and whether SFN altered the immune balance after HBV infection. RESULTS: We found that SFN was able to reduce HBV DNA, cccDNA, HBsAg, HBeAg, and HBcAg levels in serum and liver tissues of HBV-infected mice. In vitro and in vivo experiments showed that SFN could significantly increase the expression of Cd86 and iNOS and inhibit the expression of Arg1 on macrophages after HBV infection. After SFN administration, Th17 markers in liver tissue and serum were significantly increased. There was no significant changes in the proportion of Treg cells in peripheral blood, but a significant increase in the proportion of Th17 cells and decrease of the Treg/Th17 ratio. Using a network pharmacology approach, we predicted macrophage migration inhibitory factor (MIF) as a potential target of SFN and further validated that MIF expression was significantly increased after HBV infection and SFN significantly inhibited MIF expression both in vitro and in vivo. There was an upward trend in HBV markers (p>0.05) after MIF overexpression. Overexpression of MIF combined with the use of SFN resulted in a significant reversion in the expression of HBV markers and polarization of macrophages towards the M1 phenotype. CONCLUSION: Our results indicated that immunocompetent HBV CBA/CaJ mouse model is a good model to evaluate HBV infection. SFN could inhibit the expression of HBV markers, promote polarization of macrophages towards the M1 phenotype after HBV infection, change the proportion of Treg and Th17 cells. Our findings demonstrate that SFN inhibit HBV infection by inhibiting the expression of MIF and promoting the polarization of macrophages towards the M1 phenotype, which illustrates a promising therapeutic approach in HBV infection.

Interplay of IL-33 and IL-35 Modulates Th2/Th17 Responses in Cigarette Smoke Exposure HDM-Induced Asthma.

Cigarette smoke (CS) facilitates adverse effects on the airway inflammation and treatment of asthma. Here, we investigated the mechanisms by which CS exacerbates asthma. The roles of IL-33 and IL-35 in asthma development were examined by treatment with IL-33 knockout (IL-33 KO) or transfection of adenovirus encoding IL-35 (Ad-IL-35) in a murine model of cigarette smoke-exposure asthma. Furthermore, the involvement of IL-33 and IL-35 in regulating DCs and Th2/Th17 cells was examined in a coculture system of DCs with CD4+ T cells. Additionally, we observed the effect of CpG-ODNs on the balance of IL-33 and IL-35. We show that CS and house dust mite (HDM) exposure induced IL-33 and suppressed IL-35 levels in cigarette smoke-exposure asthma in vivo and in vitro. Treatment with IL-33 KO or Ad-IL-35 significantly attenuated airway hyperreactivity, goblet hyperplasia, airway remodelling, and eosinophil and neutrophil infiltration in the lung tissues from asthmatic mice. Furthermore, we demonstrated reciprocal regulation between CS and HDM-modulated IL-33 and IL-35. Mechanistically, IL-33 KO (or anti-ST2) and Ad-IL-35 attenuated Th2- and Th17-associated inflammation by downregulating TSLP-DC signalling. Finally, administration of CpG-ODNs suppressed the expression of IL-33/ST2 and elevated the levels of IL-35, which is mainly derived from CD4+Foxp+ Tregs, to alleviate Th2- and Th17-associated inflammation by inhibiting the activation of BMDCs. Taken together, the IL-33/ST2 pathway drives the DC-Th2 and Th17 responses of cigarette smoke-exposure asthma, while IL-35 has the opposite effect. CpG-ODNs represent a potential therapeutic strategy for modulating the balance of IL-33 and IL-35 to suppress allergic airway inflammation.

17-ß Estradiol (E2) distinctly regulates the expression of IL-4 and IL-13 in Th2 cells via modulating the interplay between GATA3 and PU.1.

17-ß Estradiol (E2) has long standing known functions in regulating human physiology as well as immune system. E2 is known to elicit a protective role against experimental autoimmune encephalomyelitis (EAE) and has been used as a drug for treatment against multiple sclerosis. Moreover, E2 regulates the adaptive immune system by directly affecting the T helper cell subsets differentiation and antibody secretion mediated by B cells. Reports have shown that E2 promotes Th1 and Treg cell differentiation; whereas it attenuated the Th17 and Tfh cell differentiation. Albeit multiple and contrasting studies, the mechanisms of behind E2 action on Th2 cells remained understudied. Hence, we sought to dissect the impact of E2 in Th2 cell differentiation. In this study, we elucidated the molecular mechanisms behind E2-mediated regulation of the differentiation of Th2 cells. We observed that E2 significantly attenuated the IL-4-secreting Th2 population in an ERα-dependent manner. We validated these findings using ICI 182, 780, an antagonist to ERα, not ERß and ectopically overexpressing ERα in Th2 cells. We further determined that ERα alters the recruitment of GATA3 and PU.1 to Il4 gene by directly interacting with them. This altered recruitment was observed to be stronger at Il4 than Il13 locus. Interestingly, we detected a distinct recruitment of GATA3 and PU.1 at Il13 gene; however, there was no E2-mediated broad alteration in the recruitment of histone-modifiers at Il13 locus. These findings suggest that E2 regulates Il4 in a distinctly separate mechanism as opposed to Il13 locus in Th2 cells.

Human placenta-derived mesenchymal stem cells ameliorate diabetic kidney disease by modulating the T helper 17 cell/ regulatory T-cell balance through the programmed death 1 / programmed death-ligand 1 pathway.

AIM: To investigate the therapeutic effects and immunomodulatory mechanisms of human placenta-derived mesenchymal stem cells (PMSCs) in diabetic kidney disease (DKD). METHODS: Streptozotocin-induced DKD rats were administered an equivalent volume of saline or PMSCs (1 × 106 in 2 mL phosphate-buffered saline per rat) for 3 weeks. Eight weeks after treatment, we examined the biochemical parameters in the blood and urine, the ratio of T helper 17 cells (Th17) and regulatory T cells (Treg) in the blood, cytokine levels in the kidney and blood, and renal histopathological changes. In addition, we performed PMSC tracing and renal transcriptomic analyses using RNA-sequencing. Finally, we determined whether PMSCs modulated the Th17/Treg balance by upregulating programmed death 1 (PD-1) in vitro. RESULTS: The PMSCs significantly improved renal function, which was assessed by serum creatinine levels, urea nitrogen, cystatin C levels, urinary albumin-creatinine ratio, and the kidney index. Further, PMSCs alleviated pathological changes, including tubular vacuolar degeneration, mesangial matrix expansion, and glomerular filtration barrier injury. In the DKD rats in our study, PMSCs were mainly recruited to immune organs, rather than to the kidney or pancreas. PMSCs markedly promoted the Th17/Treg balance and reduced the levels of pro-inflammatory cytokines (interleukin [IL]-17A and IL-1ß) in the kidney and blood of DKD rats. In vitro experiments showed that PMSCs significantly reduced the proportion of Th17 cells and increased the proportion of Treg cells by upregulating PD-1 in a cell-cell contact manner and downregulating programmed death-ligand 1 (PD-L1) expression in PMSCs, which reversed the Th17/Treg balance. CONCLUSION: We found that PMSCs improved renal function and pathological damage in DKD rats and modulated Th17/Treg balance through the PD-1/PD-L1 pathway. These findings provide a novel mechanism and basis for the clinical use of PMSCs in the treatment of DKD.

PIM kinases regulate early human Th17 cell differentiation.

The serine/threonine-specific Moloney murine leukemia virus (PIM) kinase family (i.e., PIM1, PIM2, and PIM3) has been extensively studied in tumorigenesis. PIM kinases are downstream of several cytokine signaling pathways that drive immune-mediated diseases. Uncontrolled T helper 17 (Th17) cell activation has been associated with the pathogenesis of autoimmunity. However, the detailed molecular function of PIMs in human Th17 cell regulation has yet to be studied. In the present study, we comprehensively investigated how the three PIMs simultaneously alter transcriptional gene regulation during early human Th17 cell differentiation. By combining PIM triple knockdown with bulk and scRNA-seq approaches, we found that PIM deficiency promotes the early expression of key Th17-related genes while suppressing Th1-lineage genes. Further, PIMs modulate Th cell signaling, potentially via STAT1 and STAT3. Overall, our study highlights the inhibitory role of PIMs in human Th17 cell differentiation, thereby suggesting their association with autoimmune phenotypes.

Increased gene expression of CCR6 and RORγt in peripheral blood cells of rheumatoid arthritis patients and their correlation with anti-cyclic citrullinated peptide and disease activity.

OBJECTIVES: The significance of T helper 17 (Th17) cells in the pathogenesis of rheumatoid arthritis (RA) has recently been demonstrated in many studies. Retinoic acid receptor-related orphan receptor γt (RORγt) is a transcription factor that is specifically involved in the generation of Th17 cells. Besides, the chemokine receptor CCR6, the receptor for CCL20, is characteristically expressed by these cells. Considering the pivotal roles of Th17 cells in RA pathogenesis, in this study, we assessed the gene expression of CCR6 and RORγt in the peripheral blood leukocytes of new case RA patients. Also, we evaluated their association with anticyclic citrullinated peptide (anti-CCP) antibodies and disease activity. METHODS: Forty-five new case RA patients and 45 healthy persons have been recruited in this investigation. The gene expression of CCR6 and RORγt was evaluated by quantitative real-time PCR (qRT-PCR), and anti-CCP antibodies plasma levels were measured using the enzyme-linked immunosorbent assay (ELISA) technique. Disease activity was measured according to the disease activity score-28 (DAS-28) formula. RESULTS: The gene expression of CCR6 and RORγt increased remarkably in new case RA patients compared to healthy controls (p < .05 and p < .01, respectively). Moreover, there was a positive correlation between RORγt gene expression and parameters, including gene expression of CCR6 (p = .001, r = .461), plasma levels of CCL20 (p = .0009, r = .477), ESR (p = .004, r = .419), DAS-28 (p = .006, r = .402), anti-CCP (p = .019, r = .346), and RF (p = .001, r = .451). Also, CCR6 gene expression was positively associated with the DAS-28 (p = .037, r = .310), plasma levels of anti-CCP (p = .037, r = .312), and ESR (p = .029, r = .327). CONCLUSION: Increased gene expression of CCR6 and RORγt in peripheral blood leukocytes of new case RA patients may contribute to the exacerbation and pathogenesis of RA.