Cell Th2 Cytokine Research Articles

Interconnection of the Gut-Skin Axis in NC/Nga Mouse with Atopic Dermatitis: Effects of the Three Types of Bifidobacterium bifidum CBT-BF3 (Probiotics, Postbiotics, and Cytosine-Phosphate-Guanine Oligodeoxynucleotide) on T Cell Differentiation and Gut Microbiota.

The gut microbiota is an immune system regulator in the gut-skin axis. Dysfunctional interactions between the gut microbiota and the gut immune system can lead to the development of skin diseases such as atopic dermatitis (AD). Probiotics and postbiotics positively affect the balance of the gut microbiota, immune regulation, protection against pathogens, and barrier integrity. This study investigated the effects of probiotic Bifidobacterium bifidum, postbiotic B. bifidum (heat-killed), and cytosine-phosphate-guanine oligodeoxynucleotide (CpG ODN) on the gut microbiota and T cell differentiation in NC/Nga mice induced with AD. 2,4-Dinitrochlorobenzene-induced AD mice had an increased SCORing atopic dermatitis-index and increased mRNA expression levels of Th2 and Th17 cell transcription factors and cytokines, and thymic stromal lymphopoietin (TSLP) cytokine in their mesenteric lymph nodes (mLNs; p<0.05). However, oral administration of the three types of B. bifidum (probiotics, postbiotics, CpG ODN) to AD mice decreased the mRNA expression levels of Th2 and Th17 cell transcription factors and cytokines as well as TSLP cytokine. They increased the mRNA expression levels of regulatory T (Treg) cell transcription factor and cytokine, galectin-9, and filaggrin genes (p<0.05). These effects were more noticeable in the mLNs than in the spleen. In addition, AD mice showed a decrease in Faecalibacterium prausnitzii, Roseburia spp., Leuconostoc citreum, Weissella cibaria, and Weissella koreensis (p<0.05). However, oral administration of the three types of B. bifidum increased Bacteroides spp., Bifidobacterium spp., F. prausnitzii, and Roseburia spp. (p<0.05).

CD4+ T cell-associated cytokines induce a chronic pro-inflammatory phenotype in induced pluripotent stem cell-derived midbrain astrocytes.

Astrocytes are mediators of homeostasis but contribute to neuroinflammation in Parkinson's disease (PD). Mounting evidence suggests involvement of peripheral immune cells in PD pathogenesis. Therefore, this study aimed to determine the potential role of peripheral immune secreted cytokines in modulating midbrain astrocyte reactivity. Human iPSC-derived midbrain astrocytes were exposed to 5% and 10% CD4+ T cell conditioned media (CD4CM) for 24 h, 72 h, and 7 days to assess chronic exposure. Additionally, astrocytes were exposed to the Th17 cell cytokine, IL-17A (10 ng/mL), alone and in combination with TNF-α (0.3 ng/mL) to assess potential synergistic effects of both cytokines at 24 h, 72 h, and 7 days. CD4CM induced acute and chronic alterations in midbrain astrocytes. Increased NFκB translocation to the nucleus, increased expression of the pro-inflammatory genes, IL-1β, CXCL10 at 24 h, C3, LCN2, IL-6 at 24 and 48 h, as well as an increase in their release of pro-inflammatory cytokines IL-6 and CXCL10 at both these time points were observed. A synergistic response to the combination of IL-17A and TNF-α on increasing inflammatory gene expression and cytokine release occurred. IL-17A and TNF-α increased intensity of S100β at 24 h, decreased nuclear area and increased circularity of astrocytes at 72 h. A synergistic effect on γH2AX intensity at 72 h and an increase in LDH release at 7 days was observed. Our results demonstrate that IL-17A and TNF-α act synergistically, enhancing midbrain astrocyte reactivity to a similar degree as CD4CM. This highlights the importance of the peripheral immune secreted cytokines in increasing the reactivity status of midbrain astrocytes, implicating their role in PD.

Stress-induced VIPergic activation mediates microbiota/Th17cell-dependent depressive-like behaviors

Chronic stress often has deleterious effects leading to the development of psychiatric diseases. The gut-brain axis represents a novel avenue for stress research. The negative effects of stress on the gut physiology have been well-described, whereas the pathways whereby stress controls microbial composition to modulate behaviors remains mainly unknown. We discovered that vasoactive intestinal peptide (VIP) activation promoted stress-induced microbial changes leading to increased infiltration of T helper (Th) 17 cells and microglial activation in the hippocampus and depressive-like behaviors, uncovering a close crosstalk between intestinal VIPergic release and the gut microbiota during stress and providing a new interaction between the nervous system and the gut microbiome after stress. Neutralization of the signature cytokine of Th17 cells, interleukin (IL)-17A, was sufficient to block depressive-like behaviors, reduce neuronal VIPergic activation and microglia activation induced by VIPergic activation after stress, opening new potential therapeutic targets for depression.

Characterization of novel CD8+ regulatory T cells and their modulatory effects in murine model of inflammatory bowel disease

Dysregulation of mucosal immune system has been proposed to be critical in the pathogenesis of inflammatory bowel diseases (IBDs). Regulatory T cells (Tregs) play an important role in regulating immune responses. Tregs are involved in maintaining intestinal homeostasis and exerting suppressive function in colitis. Our previous studies showed that a novel forkhead box protein P3 (Foxp3) negative Tregs (Treg-of-B cells), induced by culturing naïve CD4+ T cells with B cells, could protect against colitis and downregulate T helper (Th) 1 and Th17 cell cytokines in T cell-mediated colitis. In the present study, we aimed to induce Treg-of-B cells in the CD8+ T-cell population and investigate their characteristics and immunomodulatory functions. Our results showed that CD8+ Treg-of-B cells expressed Treg-associated markers, including lymphocyte-activation gene-3 (LAG3), inducible co-stimulator (ICOS), programmed death-1 (PD-1), cytotoxic T-lymphocyte-associated protein-4 (CTLA-4), tumor necrosis factor receptor superfamily member-4 (TNFRSF4, OX40), and tumor necrosis factor receptor superfamily member-18 (TNFRSF18, GITR), but did not express Foxp3. CD8+ Treg-of-B cells produced higher concentration of inhibitory cytokine interleukin (IL)-10, and expressed higher levels of cytotoxic factor granzyme B and perforin after stimulation, compared to those of CD8+CD25- T cells. Moreover, CD8+ Treg-of-B cells suppressed T cell proliferation in vitro and alleviated colonic inflammation in chronic dextran sulfate sodium (DSS)-induced colitis. In conclusion, our study identified a novel subpopulation of CD8+ Tregs with suppressive effects through cell contact. These CD8+ Treg-of-B cells might have therapeutic potential for IBDs.

Dermal White Adipose Tissue–Derived Il-33 Regulates Il-4/13 Expression in Myeloid Cells during Inflammation

Effective tissue response to infection and injury essentially relies on the fine-tuned induction and subsequent resolution of inflammation. Recent research highlighted multiple functions of dermal white adipose tissue (dWAT) beyond its traditional role as an energy reservoir. However, in contrast to other fat depots, there are only limited data about putative immune-regulatory functions of dWAT. Therefore, we investigated the impact of dWAT in the control of an acute skin inflammation. Skin inflammation triggers the activation of dWAT. In turn, soluble mediators of activated dWAT stimulate the expression of numerous genes controlling skin inflammation including the Th2 cell cytokines interleukin-4 (IL-4) and interleukin-13 (IL-13) in myeloid cells in vitro. Consistently, myeloid cells isolated from inflamed skin showed a significant upregulation of IL-4/13 expression compared to those isolated from healthy skin. Mechanistically, we demonstrate that interleukin-33 (IL-33) released from activated dWAT is responsible for IL-4/13 stimulation in myeloid cells. Interestingly, obesity attenuates IL-33 secretion in dWAT during inflammation resulting in decreased IL-4 and IL-13 expression in myeloid cells. Our data reveal an IL-33 - IL-4/13 signaling cascade initiated from dWAT in a Th2 independent context of inflammation that may contribute to limitation of inflammation. This cascade seems to be disturbed in obese individuals with prolonged inflammation.

Differential requirement for IL-2 and IL-23 in the differentiation and effector functions of Th17/ILC3-like cells in a human T cell line.

A well-documented Achilles heel of current cancer immunotherapy approaches is T cell exhaustion within solid tumor tissues. The proinflammatory cytokine interleukin (IL)-23 has been utilized to augment chimeric antigen receptor (CAR) T cell survival and tumor immunity. However, in-depth interrogation of molecular events downstream of IL-23/IL-23 receptor signaling is hampered by a paucity of suitable cell models. The current study investigates the differential contribution of IL-2 and IL-23 to the maintenance and differentiation of the IL-23 responsive Kit225 T-cell line. We observed that IL-23 enhanced cellular fitness and survival but was insufficient to drive proliferation. IL-23 rapidly induced phosphorylation of STAT1, STAT3, and STAT4, and messenger RNA expression of IL17A, the archetypal effector cytokine of T helper 17 (Th17) cells, but not their lineage markers RORC and NCR1. These observations suggest that IL-23 endowed Th17/ILC3-like effector function but did not promote their differentiation. In contrast, spontaneous differentiation of Kit225 cells toward a Th17/ILC3-like phenotype was induced by prolonged IL-2 withdrawal. This was marked by strongly elevated basal IL17A and IL17F expression and the secretion of IL-17. Together, our data present Kit225 cells as a valuable model for studying the interplay between cytokines and their contribution to T cell survival, proliferation, and differentiation.

Imbalance of Th1 and Th2 Cytokines and Stem Cell Therapy in Pathological Pain.

The pathophysiological importance of T helper 1 (Th1) and Th2 cell cytokines in pathological pain has been highly debated in recent decades. However, the analgesic strategy targeting individual cytokines still has a long way to go for clinical application. In this review, we focus on the contributions of Th1 cytokines (TNF-α, IFN-γ, and IL-2) and Th2 cytokines (IL-4, IL-5, IL-10, and IL-13) in rodent pain models and human pain-related diseases. A large number of studies have shown that Th1 and Th2 cytokines have opposing effects on pain modulation. The imbalance of Th1 and Th2 cytokines might determine the final effect of pain generation or inhibition. However, increasing evidence indicates that targeting the individual cytokine is not sufficient for the treatment of pathological pain. It is practical to suggest a promising therapeutic strategy against the combined effects of Th1 and Th2 cytokines. We summarize the current advances in stem cell therapy for pain-related diseases. Preclinical and clinical studies show that stem cells inhibit proinflammatory cytokines and release enormous Th2 cytokines that exhibit a strong analgesic effect. Therefore, a shift of the imbalance of Th1 and Th2 cytokines induced by stem cells will provide a novel therapeutic strategy against intractable pain. It is extremely important to reveal the cellular and molecular mechanisms of stem cell-mediated analgesia. The efficiency and safety of stem cell therapy should be carefully evaluated in animal models and patients with pathological pain.

Short-term administration of Qipian®, a mixed bacterial lysate, inhibits airway inflammation in ovalbumin-induced mouse asthma by modulating cellular, humoral and neurogenic immune responses

AimsQipian® is a commercialized agent composed of extracts of three genera of commensal bacteria, and its mechanism of action on asthma is unclear. This study aimed to examine the impact of Qipian® on airway inflammation and investigate the underlying mechanisms. Materials and methodsQipian® or dexamethasone (DEX) was administered before OVA challenge in an ovalbumin-induced asthma mouse model, and then asthmatic symptoms were observed and scored. Samples of lung tissues, blood, and bronchoalveolar lavage fluid (BALF) were collected, and eosinophils (Eos), immunoglobins (Igs), and type 1 T helper (Th1)/Th2 cell cytokines were measured. Mucus production in the lung was assessed by periodic acid-Schiff (PAS) staining. The effects of Qipian® on dendritic and T regulatory (Treg) cells were investigated using flow cytometry. Key findingsThe short-term administration of Qipian® significantly inhibited the cardinal features of allergic asthma, including an elevated asthmatic behaviour score, airway inflammation and immune response. Histological analysis of the lungs showed that Qipian® attenuated airway inflammatory cell infiltration and mucus hyperproduction. Qipian® restored Th1/Th2 imbalance by decreasing interleukin (IL)-4, IL-5, and IL-13 while increasing interferon (IFN)-γ and IL-10. Further investigation revealed that Qipian® treatment induced the upregulation of CD4+CD25+Foxp3+ Treg cells and CD103+ DCs and downregulation of tachykinins neurokinin A (NKA) and NKB in the lung. SignificanceOur findings suggested that short-term treatment with Qipian® could alleviate inflammation in allergic asthma through restoring the Th1/Th2 balance by recruiting Treg cells to airways and inducing the proliferation of CD103+ DCs, which actually provides a new treatment option for asthma.

BHLHE40 Mediates Cross-Talk between Pathogenic TH17 Cells and Myeloid Cells during Experimental Autoimmune Encephalomyelitis.

TH17 cells are implicated in the pathogenesis of multiple sclerosis and experimental autoimmune encephalomyelitis (EAE). We previously reported that the transcription factor basic helix-loop-helix family member e40 (BHLHE40) marks cytokine-producing pathogenic TH cells during EAE, and that its expression in T cells is required for clinical disease. In this study, using dual reporter mice, we show BHLHE40 expression within TH1/17 and ex-TH17 cells following EAE induction. Il17a-Cre-mediated deletion of BHLHE40 in TH cells led to less severe EAE with reduced TH cell cytokine production. Characterization of the leukocytes in the CNS during EAE by single-cell RNA sequencing identified differences in the infiltrating myeloid cells when BHLHE40 was present or absent in TH17 cells. Our studies highlight the importance of BHLHE40 in promoting TH17 cell encephalitogenicity and instructing myeloid cell responses during active EAE.

Cutting Edge: Serpine1 Negatively Regulates Th1 Cell Responses in Experimental Autoimmune Encephalomyelitis.

Th1 cells are critical in experimental autoimmune encephalomyelitis (EAE). Serine protease inhibitor clade E1 (Serpine1) has been posited as an inhibitor of IFN-γ from T cells, although its role in autoimmunity remains unclear. In this study, we show that Serpine1 knockout (KO) mice develop EAE of enhanced severity relative to wild-type (WT) controls. Serpine1 overexpression represses Th1 cell cytokine production and pathogenicity, whereas Serpine1-KO:2D2 Th1 cells transfer EAE of increased severity in comparison with WT 2D2 Th1 cells. Notably, polarized Serpine1-KO Th1 cells display delayed expression of the Th1-specific inhibitory receptor, Tim-3 (T cell Ig and mucin-domain containing-3). Serpine1-KO:Tim-3-Tg Th1 cells, which transgenically overexpress Tim-3, showed increased expression of IFN-γ and reduced expression of the checkpoint molecules Lag-3 and PD-1 relative to WT Tim-3-Tg counterparts. Furthermore, Serpine1 deficiency restored the EAE phenotype of Tim-3-Tg mice that normally develop mild disease. Taken together, we identify Serpine1 as a negative regulator of Th1 cells.

Mogroside V ameliorates broiler pulmonary inflammation via modulating lung microbiota and rectifying Th17/Treg dysregulation in lipopolysaccharides-induced lung injury

The dysbiosis of lung microbiota and inflammatory factors play a crucial role in the occurrence of lipopolysaccharides (LPS)-induced lung injury. Recently, mogroside V (MGV) has received increasing attention due to its potential health benefits in pneumonia, but its complex mechanism needs further experimental elucidation. In this study, we established an LPS-induced chicken lung injury model to investigate the protective effect of MGV on LPS-induced acute lung injury in broiler and its related mechanisms. A total of 192 one-day-old white-finned broilers were randomly assigned into 4 groups with 6 replicates: 1) control group: basal diet (d 1-44), saline (d 43); 2) LPS group: basal diet (d 1-44), LPS (d 43); 3) MGV group: basal diet+0.2% MGV (d 1-44), saline (d 43); 4) MGV-LPS group: basal diet+0.2% MGV (d 1-44), LPS (d 43). The results showed that pathological examination showed that lung tissue inflammation infiltration was reduced after MGV treatment. In addition, MGV can promote the balance of Th17 and Treg cell cytokines, significantly inhibit the expression of proinflammatory cytokines (IL-1β (P < 0.01), IL-6 (P < 0.001), IL-17F (P < 0.05)), and decrease immunosuppressive target expression (PD-L1 (P < 0.01), PD-1 (P < 0.001), RORα (P < 0.001)), activating the immune system. Furthermore, 16S rRNA sequencing analysis showed that MGV treatment could increase the abundance of beneficial bacteria in the lung and reduce the abundance of bacteria associated with inflammation. Generally, MGV intervention has a preventive effect on the pathological damage induced by lipopolysaccharides. Its mechanism is related to inhibiting the inflammatory response, regulating the Th17/Treg balance, and maintaining the stability of lung microbiota.

Curcumin's spice-infused therapeutic promise: disease severity alleviation in a mouse model of multiple sclerosis via modulation of immune responses.

Multiple sclerosis (MS) is an autoimmune central nervous system (CNS) disorder indicated by demyelination, chronic inflammation, and neuronal destruction. Regional demyelination, inflammation responses, scar development, and various axonal damage are pathological characteristics of MS. Curcumin is a hydrophobic polyphenol extracted from the rhizome of the turmeric plant. In addition to anti-inflammatory effects, beneficial therapeutic effects such as antioxidant, anti-cancer and nerve protection have also been seen from this compound. The purpose of the current investigation was to provide light on the potential benefits of Curcumin in treating experimental autoimmune encephalomyelitis (EAE), the animal model of MS. in Female C57BL/6 mice were used to induce EAE through myelin oligodendroglial glycoprotein (MOG). Curcumin doses of 100 and 200mg/kg were administered orally in the treatment groups starting on the first day of EAE induction. Brains and splenocytes were extracted from euthanized animals on day 25 following EAE induction. Demyelination and leukocyte infiltration, proliferation, cytokine, and gene expression profiles were assessed. Our findings demonstrate that both low and high doses of Curcumin decreased the progression of EAE. Histological analyses revealed low infiltration of leukocytes into the CNS. Curcumin therapy enhanced Th2 and Treg cell secretion of IL-4, IL-10, and TGF-β although considerably decreasing IFN-γ and TNF-α. Curcumin-induced Th2 and Treg cell cytokine production and transcription factor gene expression (IL-13, GATA3, STAT6 and IL-35, CTLA4, Foxp3) and anti-inflammatory cytokines (IL-27, IL-33). Overall, these findings provide additional evidence that Curcumin can slow disease development and alleviate symptoms in EAE through stimulating Treg and Th2 cell polarization. They support Curcumin's potential therapeutic role in MS.

TRAF5 regulates intestinal mucosal Th1/Th17 cell immune responses via Runx1 in colitis mice.

Inflammatory bowel disease (IBD) is a chronic gastrointestinal inflammatory disease associated with CD4+ Th1 and Th17 cell immune responses. Tumour necrosis factor-associated factor 5 (TRAF5) deficiency has been shown to aggravate DSS-induced colitis. However, the potential role of TRAF5 in regulating CD4+ T cell immune responses in the pathogenesis of IBD remains unclear. TRAF5-/- CD4+ CD45RBhigh T cells and WT CD4+ CD45RBhigh T cells were transferred to Rag2-/- mice via intravenous (i.v.) tail injection, respectively, to establish a chronic colitis model. Adeno-associated virus (AAV)-mediated gene knockout technique was used to knock out runt-associated transcription factor 1 (Runx1) expression in vivo. Specific cytokines of Th1 and Th17 cells were detected by quantitative RT-PCR, immunohistochemistry, ELISA, and flow cytometry. In T-cell transfer colitis mice, the Rag2-/- mice reconstituted with TRAF5-/- CD4+ CD45RBhigh T cells showed more severe intestinal inflammation than the WT control group, which was characterised by increased expression of INF-γ, TNF-α, IL-17a. Furthermore, we found that the INF-γ+ CD4+ , IL17a+ CD4+ , and INF-γ+ IL17a+ CD4+ T cells in the intestinal mucosa of Rag2-/- mice reconstituted with TRAF5-/- CD4+ CD45RBhigh T cells were significantly higher than those of the WT control group by flow cytometry. Mechanistically, knockout Runx1 inhibited the differentiation of TRAF5-/- CD4+ T cells into Th1 and Th17 cells in the intestinal mucosa of T-cell transfer colitis mice. TRAF5 regulates Th1 and Th17 cell differentiation and immune response through Runx1 to participate in the pathogenesis of colitis. Thus targeting TRAF5 in CD4+ T cells may be a novel treatment for IBD.

Abstract P1072: Microneedle Patch Loaded With Il-4 Macroparticles Facilitates Heart Repair Through Macrophages Mediated Cardiomyocyte Phenotype Transition

Ischemic heart disease remains the leading cause of mortality worldwide, but significant progress has been made in optimizing the treatment of acute myocardial infarction (MI) with percutaneous coronary intervention techniques. However, the increased pool of post-MI survivors has led to a higher prevalence of heart failure (HF) secondary to coronary artery disease, making it a major public health issue. Monocytes recruited from circulation differentiate into pro-inflammatory macrophages (M1-like) responsible for post-MI inflammation and cellular debris removal. As a unique Th2 cell cytokine, Interleukin 4 (IL-4) has been widely established as a powerful agent for the polarization of anti-inflammatory macrophages that promote tissue repair. However, there are limitations such as local and targeted delivery have hampered the successful translation of IL-4 therapy. In this study, we created an IL-4 microparticle-loaded microneedle patch (IL-4 MP-MN) for localized delivery of IL-4 to the MI region and tested the therapeutic effects in a rat model of MI. Our preliminary data suggested that IL-4 MP-MN treatment promoted cardiomyocyte proliferation and induced an anti-inflammatory microenvironment, which further led to a cardiomyocyte phenotype shift from "self-rescue" to "assisted-rescue" mode. Additionally, we successfully translated the therapeutic effects of IL-4 MP-MN in a porcine model of MI for testing therapeutic feasibility, safety, and efficacy.

IL-17A deficiency alleviates PM-induced allergic asthma by suppressing Th17 cell secretion cytokines and mucus overproduction

Abstract Particulate matter (PM) aggravates airway and lung inflammatory response in allergic asthma by directly inducing Th17 cells to secrete Th17 cell-associated inflammatory factors and chemokines. IL-17A is a key Th17 cell secretion pro-inflammatory cytokine. In this study, we investigated the role of IL-17A in PM-induced allergic asthma in mice. 7–8 weeks old wild type (WT) mice, and similarly IL-17A knockout (KO) mice, were divided into four experimental groups (healthy control, PM only, OVA only, OVA+PM treatment groups) and treated accordingly. Inflammatory cell and eosinophil infiltration were increased in the PM-induced WT mice compared to WT healthy control, but were decreased in KO mice compared to PM-induced WT mice. Among toll-like receptors (TLRs) that play an important role in innate immune response, TLR2/4/7 expression was significantly increased in PM-induced WT mice, but was reduced in KO mice. Furthermore, we observed decrease in mRNA expression of IL-13, IL-17A, IL-22, and TGF-β among cytokines of Th2 and Th17 cells in KO mice. PM-induced WT mice facilitated the overt histopathological symptoms of allergic asthma such as mucus overproduction and goblet cell hyperplasia while KO mice showed mitigated such responses compared to PM-induced allergic asthma WT mice. These results prove that IL-17A plays a key role in pathogenesis of PM-induced allergic asthma. This research was funded by the Ministry of Education. This research was funded by the Ministry of Education

Transcriptome Analysis Identifies Biomarkers for the Diagnosis and Management of Psoriasis Complicated with Depression.

Psoriasis is a systemic inflammatory disease, and the mechanism that links psoriasis to depression is still elusive. Hence, this study aimed to elucidate the potential pathogenesis of psoriasis and depression comorbidity. The gene expression profiles of psoriasis (GSE34248, GSE78097 and GSE161683) and depression (GSE39653) were downloaded from the Gene Expression Omnibus (GEO) DataSets. Functional annotation, protein-protein interaction (PPI) network and module construction, and hub gene identification and co-expression analysis were performed, following identification of the common differentially expressed genes (DEGs) of psoriasis and depression. A total of 115 common DEGs (55 up-regulated and 60 down-regulated) were identified between psoriasis and depression. Functional analysis indicated that T cell activation and differentiation were predominantly implicated in the potential pathogenesis of these two diseases. In addition, Th17 cell differentiation and cytokines is closely related to both. Finally, 17 hub genes were screened, including CTLA4, LCK, ITK, IL7R, CD3D, SOCS1, IL4R, PRKCQ, SOCS3, IL23A, PDGFB, PAG1, TGFA, FGFR1, RELN, ITGB5 and TNXB, which re-emphasized the importance of the immune system in psoriasis and depression. Our study reveals the common pathogenesis of psoriasis and depression. These common pathways and hub genes may apply to a molecular screening tool for depression in psoriasis patients, which could help dermatologists optimize patient management in routine care.

Essential role of IL-17A in activating Treg cells in autoimmune uveitis

Abstract The balance between Th17 cells and regulatory T (Treg) cells is critical for host homeostasis. The signature cytokine of Th17 cells, IL-17A, is a pro-inflammatory cytokine associated with various autoimmune diseases in patients and in animal models. Our previous study demonstrated that IL-17A limits pathogenicity of Th17 cells by inducing IL-24. In this study, we investigate the role of IL-17A in regulating Treg cells. In-vitro studies showed that IL-17A promotes both the differentiation and suppressive functions of Treg cells. Adoptive transfer of IL-17A-treated Treg cells is more potent to ameliorate experimental autoimmune uveitis (EAU) in mice when compared to the control Treg cells. We found that the induction of Treg cells is impaired in Il17ra −/−mice after EAU immunization and Il17ra −/−naïve T cells are less effective in their differentiation into Treg cells in EAU compared to wild-type cells. Mechanistic studies revealed that IL-17A activates NF-kB signaling and inhibits TAZ, a Foxp3 suppressor, during Treg cell differentiation. In conclusion, our data suggest that IL-17A is involved in Tregs induction and/or maintenance, and that this has a role in controlling the autoimmune response. Natural Science Foundation of Guangdong Province (2019A1515010956, 2021A1515010569, 2022A1515012450) Fundamental Research Fund of the State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center.

A bifurcated role for c-Maf in Th2 and Tfh2 cells during helminth infection

Differences in transcriptomes, transcription factor usage, and function have identified T follicular helper 2 (Tfh2) cells and T helper 2 (Th2) cells as distinct clusters of differentiation 4+",(CD4) T-cell subsets in settings of type-2 inflammation. Although the transcriptional programs driving Th2 cell differentiation and cytokine production are well defined, dependence on these classical Th2 programs by Tfh2 cells is less clear. Using cytokine reporter mice in combination with transcription factor inference analysis, the b-Zip transcription factor c-Maf and its targets were identified as an important regulon in both Th2 and Tfh2 cells. Conditional deletion of c-Maf in T cells confirmed its importance in type-2 cytokine expression by Th2 and Tfh2 cells. However, while c-Maf was not required for Th2-driven helminth clearance or lung eosinophilia, it was required for Tfh2-driven Immunoglobulin E production and germinal center formation. This differential regulation of cell-mediated and humoral immunity by c-Maf was a result of redundant pathways in Th2 cells that were absent in Tfh2 cells, and c-Maf-specific mechanisms in Tfh2 cells that were absent in Th2 cells. Thus, despite shared expression by Tfh2 and Th2 cells, c-Maf serves as a unique regulator of Tfh2-driven humoral hallmarks during type-2 immunity.

Targeted GATA3 knockdown in activated T cells via pulmonary siRNA delivery as novel therapy for allergic asthma.

GATA3 gene silencing in activated T cells displays a promising option to early-on undermine pathological pathways in the disease formation of allergic asthma. The central transcription factor of T helper 2 (Th2) cell cytokines IL-4, IL-5, and IL-13 plays a major role in immune and inflammatory cascades underlying asthmatic processes in the airways. Pulmonary delivery of small interfering RNAs (siRNA) to induce GATA3 knockdown within disease related T cells of asthmatic lungs via RNA interference (RNAi) presents an auspicious base to realize this strategy, however, still faces some major hurdles. Main obstacles for successful siRNA delivery in general comprise stability and targeting issues, while in addition the transfection of T cells presents a particularly challenging task itself. In previous studies, we have developed and advanced an eligible siRNA delivery system composed of polyethylenimine (PEI) as polycationic carrier, transferrin (Tf) as targeting ligand and melittin (Mel) as endosomolytic agent. Resulting Tf-Mel-PEI polyplexes exhibited ideal characteristics for targeted siRNA delivery to activated T cells and achieved efficient and sequence-specific gene knockdown in vitro. In this work, the therapeutic potential of this carrier system was evaluated in an optimized cellular model displaying the activated status of asthmatic T cells. Moreover, a suitable siRNA sequence combination was found for effective gene silencing of GATA3. To confirm the translatability of our findings, Tf-Mel-PEI polyplexes were additionally tested ex vivo in activated human precision-cut lung slices (PCLS). Here, the formulation showed a safe profile as well as successful delivery to the lung epithelium with 88% GATA3 silencing in lung explants. These findings support the feasibility of Tf-Mel-PEI as siRNA delivery system for targeted gene knockdown in activated T cells as a potential novel therapy for allergic asthma.

High-fat diet-induced resistance to helminth infection via alternative induction of type 2 immunity

Gastrointestinal nematode infections cause morbidity and socioeconomic loss in the most deprived communities. The shift in the context of obesity has led to spatial overlap with endemic gastrointestinal nematode regions resulting in the emergence of a novel comorbidity. Despite this, the impact of a high-fat diet (HFD) on immune-regulated protection against gastrointestinal infections remains largely unknown. We employed the murine model of nematode infection, Trichuris muris, to investigate the effect of an HFD on the immune response against chronic infection. Surprisingly, diet-induced obesity drove parasite expulsion in both single and repeated trickle low doses of T. muris eggs. Mechanistically, an HFD increased the expression of the ST2 receptor on CD4+ T cells, priming an enhanced type 2 helper T (Th2) cell cytokine production following interleukin (IL)-33 stimulation ex vivo. Despite IL-33-/- mice demonstrating that IL-33 is not critical for host protective immunity to T. muris under a conventional diet, HFD-fed T-cell deplete mice adoptively transferred with ST2-/- CD4 T cells were unable to expel a T. muris infection unlike those transferred with ST2-sufficient cells. Collectively, this study demonstrates that an HFD primes CD4+ T cells to utilize the IL-33-ST2 axis in a novel induction of type 2 immunity, providing insights into the emerging comorbidities of obesity and nematode infection.