Deubiquitination of aryl hydrocarbon receptor (AhR) by USP21 negatively regulates Th17 cells differentiation.

Aryl hydrocarbon receptor (AhR) is a key transcription factor that modulates the differentiation of T helper 17 (Th17) cells. How AhR is regulated at the post-translational level in Th17 cells remains largely unclear. Here we identify USP21 as a newly defined deubiquitinase of AhR. We demonstrate that USP21 interacts with and stabilizes AhR by removing the K48-linked polyubiquitin chains from AhR. Interestingly, USP21 inhibits the transcriptional activity of AhR in a deubiquitinating-dependent manner. USP21 deubiquitinates AhR at the K432 residue, and the maintenance of ubiquitination on this site is required for the intact transcriptional activity of AhR. Moreover, the deficiency of USP21 promotes the differentiation of Th17 cells both in vitro and in vivo. Consistently, adoptive transfer of USP21 deficient naïve CD4+ T cells elicits more severe colitis in Rag1-/- recipients. Therefore, our study reveals a novel mechanism in which USP21 deubiquitinates AhR and negatively regulates the differentiation of Th17 cells.

A Th17 cell-intrinsic glutathione/mitochondrial-IL-22 axis protects against intestinal inflammation.

The intestinal tract generates significant reactive oxygen species (ROS), but the role of T cell antioxidant mechanisms in maintaining intestinal homeostasis is poorly understood. We used T cell-specific ablation of the catalytic subunit of glutamate cysteine ligase (Gclc), which impaired glutathione (GSH) production, crucially reducing IL-22 production by Th17 cells in the lamina propria, which is critical for gut protection. Under steady-state conditions, Gclc deficiency did not alter cytokine secretion; however, C. rodentium infection induced increased ROS and disrupted mitochondrial function and TFAM-driven mitochondrial gene expression, resulting in decreased cellular ATP. These changes impaired the PI3K/AKT/mTOR pathway, reducing phosphorylation of 4E-BP1 and consequently limiting IL-22 translation. The resultant low IL-22 levels led to poor bacterial clearance, severe intestinal damage, and high mortality. Our findings highlight a previously unrecognized, essential role of Th17 cell-intrinsic GSH in promoting mitochondrial function and cellular signaling for IL-22 protein synthesis, which is critical for intestinal integrity and defense against gastrointestinal infections.

Pretransplant, Th17 dominant alloreactivity in highly sensitized kidney transplant candidates.

Introduction: Sensitization to donor human leukocyte antigen (HLA) molecules prior to transplantation is a significant risk factor for delayed access to transplantation and to long-term outcomes. Memory T cells and their cytokines play a pivotal role in shaping immune responses, thereby increasing the risk of allograft rejection among highly sensitized patients. This study aims to elucidate the precise contribution of different CD4+ memory T cell subsets to alloreactivity in highly sensitized (HS) kidney transplant recipients. Methods and results: Stimulation of peripheral blood mononuclear cells (PBMC) with various polyclonal stimulating agents to assess non-specific immune responses revealed that HS patients exhibit elevated immune reactivity even before kidney transplantation, compared to non-sensitized (NS) patients. HS patients' PBMC displayed higher frequencies of CD4+ T cells expressing IFNγ, IL4, IL6, IL17A, and TNFα and secreted relatively higher levels of IL17A and IL21 upon stimulation with PMA/ionomycin. Additionally, PBMC from HS patients stimulated with T cell stimulating agent phytohemagglutinin (PHA) exhibited elevated expression levels of IFNγ, IL4 and, IL21. On the other hand, stimulation with a combination of resiquimod (R848) and IL2 for the activation of memory B cells demonstrated higher expression of IL17A, TNFα and IL21, as determined by quantitative real-time PCR. A mixed leukocyte reaction (MLR) assay, employing third-party donor antigen presenting cells (APCs), was implemented to evaluate the direct alloreactive response. HS patients demonstrated notably higher frequencies of CD4+ T cells expressing IL4, IL6 and IL17A. Interestingly, APCs expressing recall HLA antigens triggered a stronger Th17 response compared to APCs lacking recall HLA antigens in sensitized patients. Furthermore, donor APCs induced higher activation of effector memory T cells in HS patients as compared to NS patients. Conclusion: These results provide an assessment of pretransplant alloreactive T cell subsets in highly sensitized patients and emphasize the significance of Th17 cells in alloimmune responses. These findings hold promise for the development of treatment strategies tailored to sensitized kidney transplant recipients, with potential clinical implications.

Activation of the interleukin-23/Th17 axis in major depression: a systematic review and meta-analysis.

The interleukin-23/Th17 axis is a promising modifiable target for depression. However, its association with depression has not been systematically evaluated. We systematically searched four databases (EMBASE, Web of Science, Pubmed and PsycINFO) for studies comparing patients with major depression and healthy controls for plasma/serum levels of Th17 cells and their canonical cytokines (interleukin-17A [IL-17A], IL-22, granulocyte macrophage colony stimulating factor [GM-CSF]). We also compared counts of Th1, Th2 and Th9 cells between depressed/non-depressed patients and their respective canonical cytokines. We performed random-effects meta-analysis of the standardised mean difference (SMD) in immune measures between groups. Risk of bias was assessed using the Newcastle-Ottawa scale. Of 3154 studies screened, 36 studies were included in meta-analysis. Patients with depression had elevated IL-17A compared to controls (SMD = 0.80 [95% CI 0.03 to 1.58], p = 0.042), an association moderated by antidepressant use (Z = 2.12, p = 0.034). Patients with depression had elevated GM-CSF (SMD = 0.54 [95% CI 0.16 to 0.91], p = 0.0047), and a trend towards higher Th17 counts (SMD = 0.44 [- 0.01 to 0.88], p = 0.052). Whilst the Th2-associated cytokine IL-5 was elevated in depression (SMD = 0.36 [95% CI 0.05 to 0.66], p = 0.02), Th2 cell counts (p = 0.97), Th1 cell counts (p = 0.17) and interferon-γ (p = 0.22) were not. Data for Th9 cells, IL-9 and IL-22 were insufficient for meta-analysis. Respectively, 22, 25 and 5 studies were good, fair and poor in quality. Patients with major depression show peripheral over-activation of the IL-23/Th17 axis. Future interventional studies should test whether this is a modifiable target for depression.

VX-509 (Decernotinib)-modified tolerogenic dendritic cells alleviate experimental autoimmune neuritis by promoting Th17/Treg rebalance.

BACKGROUND: Guillain-Barré syndrome (GBS) is an auto-inflammatory peripheral nerve disease. Dendritic cell-mediated T cell polarization is of pivotal importance in demyelinating lesions of peripheral nerves and nerve roots. However, the regulatory function of VX-509 (Decernotinib)-modified tolerogenic dendritic cells (VX-509-tolDCs) during immune remodeling following GBS remains unclear. Here, we used experimental autoimmune neuritis (EAN) as a model to investigate these aspects of GBS. METHODS: DCs were treated with varying concentrations of VX-509 (0.25, 1, and 4 µM) or served as a control using 10-8 M 1,25-(OH)2D3. Flow cytometry was employed to assess the apoptosis, phenotype, and capacity to induce T cell responses of the treated DCs. In the in vivo experiments, EAN mice received administration of VX-509-tolDCs or 1,25-(OH)2D3-tolDCs via the tail vein at a dose of 1x106 cells/mouse on days 5, 9, 13, and 17. RESULTS: VX-509 inhibited the maturation of DCs and promoted the development of tolDCs. The function of antigen-specific CD4 + T cells ex vivo was influenced by VX-509-tolDCs. Furthermore, the adoptive transfer of VX-509-tolDCs effectively alleviated inflammatory demyelinating lesions in EAN by promoting Th17/Treg (T helper 17 and regulatory T cells) rebalance. CONCLUSION: The adoptive transfer of VX-509-tolDCs alleviated inflammatory demyelinating lesions in a mouse model of GBS, known as the EAN mouse, by partially restoring the balance between Treg and Th17 cells.

Identification and functional characterization of fish IL-17 receptors suggest important roles in the response to nodavirus infection.

Th17 is a lymphocyte T helper (Th) subpopulation relevant in the control and regulation of the immune response characterized by the production of interleukin (IL)-17. This crucial cytokine family acts through their binding to the IL-17 receptors (IL-17R), having up to six members. Although the biology of fish Th17 is well-recognized, the molecular and functional characterization of IL-17 and IL-17R has been limited. Thus, our aim was to identify and characterize the IL-17R repertory and regulation in the two main Mediterranean cultured fish species, the gilthead seabream (Sparus aurata) and the European sea bass (Dicentrarchus labrax). Our in silico results showed the clear identification of six members in each fish species, from IL-17RA to IL-17RE-like, with well-conserved gene structure and protein domains with their human orthologues. All of them showed wide and constitutive transcription in naïve tissues but with highest levels in mucosal tissues, namely skin, gill or intestine. In leucocytes, T mitogens showed the strongest up-regulation in most of the il17 receptors though il17ra resulted in inhibition by most stimulants. Interestingly, in vivo nodavirus infection resulted in alterations on the transcription of il17 receptors. While nodavirus infection led to some increments in the il17ra, il17rb, il17rc and il17rd transcripts in the susceptible European sea bass, many down-regulations were observed in the resistant gilthead seabream. Our data identify the presence and conservation of six coding IL-17R in gilthead seabream and European sea bass as well as their differential regulation in vitro and upon nodavirus infection. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-024-00225-1.

Impairment of Gal-9 and Tim-3 crosstalk between Tregs and Th17 cells drives tobacco smoke-induced airway inflammation.

Overexpression of T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) on T cells has been observed in smokers. However, whether and how galectin-9 (Gal-9)/TIM-3 signal between T-regulatory cells (Tregs) and type 17 helper (Th17) cells contributes to tobacco smoke-induced airway inflammation remains unclear. Here, we aimed to explore the role of the Gal-9/TIM-3 signal between Tregs and Th17 cells during chronic tobacco smoke exposure. Tregs phenotype and the expression of TIM-3 on CD4+ T cells were detected in a mouse model of experimental emphysema. The role of TIM-3 in CD4+ T cells was explored in a HAVCR2-/- mouse model and in mice that received recombinant anti-TIM3. The crosstalk between Gal-9 and Tim-3 was evaluated by coculture Tregs with effector CD4+ T cells. We also invested the expression of Gal-9 in Tregs in patients with COPD. Our study revealed that chronic tobacco smoke exposure significantly reduces the frequency of Tregs in the lungs of mice and remarkably shapes the heterogeneity of Tregs by downregulating the expression of Gal-9. We observed a pro-inflammatory but restrained phenotypic transition of CD4+ T cells after tobacco smoke exposure, which was maintained by TIM-3. The restrained phenotype of CD4+ T cells was perturbed when TIM-3 was deleted or neutralised. Tregs from the lungs of mice with emphysema displayed a blunt ability to inhibit the differentiation and proliferation of Th17 cells. The inhibitory function of Tregs was partially restored by using recombinant Gal-9. The interaction between Gal-9 and TIM-3 inhibits the differentiation of Th17 cells and promotes apoptosis of CD4+ T cells, possibly by interfering with the expression of retinoic acid receptor-related orphan receptor gamma t. The expression of Gal-9 in Tregs was reduced in patients with COPD, which was associated with Th17 response and lung function. These findings present a new paradigm that impairment of Gal-9/Tim-3 crosstalk between Tregs and Th17 cells during chronic tobacco smoke exposure promotes tobacco smoke-induced airway/lung inflammation.

Peripheral Th17/Treg imbalance in Chinese patients with untreated antisynthetase syndrome associated interstitial lung disease.

Interstitial lung disease (ILD) is a common and fatal manifestation of antisynthetase syndrome (ASS). The aim of this study was to provide new insight into investigate peripheral blood lymphocytes, CD4+ T cells, cytokine levels and their relation to the clinical profile of untreated patients with ASS-ILD. The retrospective study population included thirty patients diagnosed with ASS-ILD and 30 healthy controls (HCs). Baseline clinical and laboratory data were collected for all subjects, including peripheral blood lymphocyte, CD4+ T cell subsets measured by flow cytometry, and serum cytokine levels measured by multiple microsphere flow immunofluorescence. Their correlations with clinical and laboratory findings were analyzed by Pearson's or Spearman's correlation analysis. In addition, the Benjamini-Hochberg method was used for multiple correction to adjust the p-values. Patients with ASS-ILD had lower CD8+ T cells, higher proportion of Th17 cells and Th17/Treg ratio than HCs. Serum cytokine levels (IL-1ß, IL-6, IL-12, IL-17, IL-8, IL-2, IL-4, IL-10, TNF-α and IFN-γ) were higher in patients with ASS-ILD than HCs. Moreover, Th17/Treg ratio was negatively correlated with diffusing capacity of carbon monoxide (DLCO)%. Our study demonstrated abnormalities of immune disturbances in patients with ASS-ILD, characterized by decreased CD8+ T cells and an increased Th17/Treg ratio, due to an increase in the Th17 cells. These abnormalities may be the immunological mechanism underlying the development of ILD in ASS.

VISTA Deficiency Exacerbates the Development of Pulmonary Fibrosis by Promoting Th17 Differentiation.

Background: Interstitial lung disease (ILD), characterized by pulmonary fibrosis (PF), represents the end-stage of various ILDs. The immune system plays an important role in the pathogenesis of PF. V-domain immunoglobulin suppressor of T-cell activation (VISTA) is an immune checkpoint with immune suppressive functions. However, its specific role in the development of PF and the underlying mechanisms remain to be elucidated. Methods: We assessed the expression of VISTA in CD4 T cells from patients with connective tissue disease-related interstitial lung disease (CTD-ILD). Spleen cells from wild-type (WT) or Vsir -/- mice were isolated and induced for cell differentiation in vitro. Additionally, primary lung fibroblasts were isolated and treated with interleukin-17A (IL-17A). Mice were challenged with bleomycin (BLM) following VISTA blockade or Vsir knockout. Moreover, WT or Vsir -/- CD4 T cells were transferred into Rag1 -/- mice, which were then challenged with BLM. Results: VISTA expression was decreased in CD4 T cells from patients with CTD-ILD. Vsir deficiency augmented T-helper 17 (Th17) cell differentiation in vitro. Furthermore, IL-17A enhanced the production of inflammatory cytokines, as well as the differentiation and migration of lung fibroblasts. Both VISTA blockade and knockout of Vsir increased the percentage of IL-17A-producing Th17 cells and promoted BLM-induced PF. In addition, mice receiving Vsir -/- CD4 T cells exhibited a higher percentage of Th17 cells and more severe PF compared to those receiving WT CD4 T cells. Conclusion: These findings demonstrate the significant role of VISTA in modulating the development of PF by controlling Th17 cell differentiation. These insights suggest that targeting VISTA could be a promising therapeutic strategy for PF.

CD169+ Skin Macrophages Function as a Specialized Subpopulation in Promoting Psoriasis-like Skin Disease in Mice.

Skin macrophages are critical to maintain and restore skin homeostasis. They serve as major producers of cytokines and chemokines in the skin, participating in diverse biological processes such as wound healing and psoriasis. The heterogeneity and functional diversity of macrophage subpopulations endow them with multifaceted roles in psoriasis development. A distinct subpopulation of skin macrophages, characterized by high expression of CD169, has been reported to exist in both mouse and human skin. However, its role in psoriasis remains unknown. Here, we report that CD169+ macrophages exhibit increased abundance in imiquimod (IMQ) induced psoriasis-like skin lesions. Specific depletion of CD169+ macrophages in CD169-ditheria toxin receptor (CD169-DTR) mice inhibits IMQ-induced psoriasis, resulting in milder symptoms, diminished proinflammatory cytokine levels and reduced proportion of Th17 cells within the skin lesions. Furthermore, transcriptomic analysis uncovers enhanced activity in CD169+ macrophages when compared with CD169- macrophages, characterized by upregulated genes that are associated with cell activation and cell metabolism. Mechanistically, CD169+ macrophages isolated from IMQ-induced skin lesions produce more proinflammatory cytokines and exhibit enhanced ability to promote Th17 cell differentiation in vitro. Collectively, our findings highlight the crucial involvement of CD169+ macrophages in psoriasis development and offer novel insights into the heterogeneity of skin macrophages in the context of psoriasis.

miR-155 promotes Th17 differentiation by targeting FOXP3 to aggravate inflammation in MRSA pneumonia.

BACKGROUND: Previous researches have clarified that miR-155 is increased in methicillin-resistant Staphylococcus aureus (MRSA) pneumonia, and modulates Th9 differentiation. Like Th9 cells, Th17 cells were also a subset of CD4+ T cells and involved in MRSA pneumonia progression. This work aimed to investigate the role and mechanism of miR-155 in Th17 differentiation. METHODS: Bronchoalveolar lavage fluid (BALF) was collected from children with MRSA pneumonia and bronchial foreign bodies. MRSA-infected murine model was established followed by collecting BALF and lung tissues. qRT-PCR, ELISA and flow cytometry were performed to examine the mRNA expression and concentration of IL-17 and the number of Th17 cells in above samples. HE and ELISA were used to evaluate inflammatory responses in lung. Furthermore, CD4+ T cells were isolated from BALF of children for in vitro experiments. After treatments with miR-155 mimic/inhibitor, the roles of miR-155 in Th17/IL-17 regulation were determined. The downstream of miR-155 was explored by qRT-PCR, western blotting, dual luciferase reporter analysis and RIP assay. RESULTS: The levels of IL-17 and the proportion of Th17 cells were increased in children with MRSA pneumonia. A similar pattern was observed in MRSA-infected mice. On the contrary, IL-17 neutralization abolished the activation of Th17/IL-17 induced by MRSA infection. Furthermore, IL-17 blockade diminished the inflammation caused by MRSA. In vitro experiments demonstrated miR-155 positively regulated IL-17 expression and Th17 differentiation. Mechanistically, FOXP3 was a direct target of miR-155. miR-155 inhibited FOXP3 level via binding between FOXP3 and Argonaute 2 (AGO2), the key component of RNA-induced silencing complex (RISC). FOXP3 overexpression reversed elevated IL-17 levels and Th17 differentiation induced by miR-155. CONCLUSIONS: miR-155 facilitates Th17 differentiation by reducing FOXP3 through interaction of AGO2 and FOXP3 to promote the pathogenesis of MRSA pneumonia. IL-17 blockade weakens the inflammation due to MRSA, which provides a nonantibiotic treatment strategy for MRSA pneumonia.

Intergenic risk variant rs56258221 skews the fate of naive CD4+ T cells via miR4464-BACH2 interplay in primary sclerosing cholangitis.

Primary sclerosing cholangitis (PSC) is an immune-mediated liver disease of unknown pathogenesis, with a high risk to develop cirrhosis and malignancies. Functional dysregulation of T cells and association with genetic polymorphisms in T cell-related genes were previously reported for PSC. Here, we genotyped a representative PSC cohort for several disease-associated risk loci and identified rs56258221 (BACH2/MIR4464) to correlate with not only the peripheral blood T cell immunophenotype but also the functional capacities of naive CD4+ T (CD4+ TN) cells in people with PSC. Mechanistically, rs56258221 leads to an increased expression of miR4464, in turn causing attenuated translation of BACH2, a major gatekeeper of T cell quiescence. Thereby, the fate of CD4+ TN is skewed toward polarization into pro-inflammatory subsets. Clinically, people with PSC carrying rs56258221 show signs of accelerated disease progression. The data presented here highlight the importance of assigning functional outcomes to disease-associated genetic polymorphisms as potential drivers of diseases.

HSP90ß shapes the fate of Th17 cells with the help of glycolysis-controlled methylation modification.

BACKGROUND AND PURPOSE: Ulcerative colitis (UC) is a refractory inflammatory disease associated with immune dysregulation. Elevated levels of heat shock protein (HSP) 90 in the ß but not α subtype were positively associated with disease status in UC patients. This study validated the possibility that pharmacological inhibition or reduction of HSP90ß would alleviate colitis, induced by dextran sulfate sodium, in mice and elucidated its mechanisms. EXPERIMENTAL APPROACH: Histopathological and biochemical analysis assessed disease severity, and bioinformatics and correlation analysis explained the association between the many immune cells and HSP90ß. Flow cytometry was used to analyse the homeostasis and transdifferentiation of Th17 and Treg cells. In vitro inhibition and adoptive transfer assays were used to investigate functions of the phenotypically transformed Th17 cells. Metabolomic analysis, DNA methylation detection and chromatin immunoprecipitation were used to explore these mechanisms. KEY RESULTS: The selective pharmacological inhibitor (HSP90ßi) and shHSP90ß significantly mitigated UC in mice and promoted transformation of Th17 to Treg cell phenotype, via Foxp3 transcription. The phenotypically-transformed Th17 cells by HSP90ßi or shHSP90ß were able to inhibit lymphocyte proliferation and colitis in mice. HSP90ßi and shHSP90ß selectively weakened glycolysis by stopping the direct association of HSP90ß and GLUT1, the key glucose transporter, to accelerate ubiquitination degradation of GLUT1, and enhance the methylation of Foxp3 CNS2 region. Then, the mediator path was identified as the "lactate-STAT5-TET2" cascade. CONCLUSION AND IMPLICATIONS: HSP90ß shapes the fate of Th17 cells via glycolysis-controlled methylation modification to affect UC progression, which provides a new therapeutic target for UC.

Predicting role of Myc-induced nuclear antigen 53 in determining the development and severity of systemic lupus erythematosus.

Introduction: Systemic lupus erythematosus (SLE) as an autoimmune disease can relate to an imbalance between regulatory T cells (Tregs) and Th17 cells. Previous reports have shown that Myc-induced nuclear antigen (Mina) 53 protein is involved in the developments of Tregs and Th17 cells. Therefore, the current study focused on determining whether Mina53 level is correlated to the severity of SLE. Methods: The blood samples were collected from 60 patients with SLE (30 cases with mild SLE and 30 cases with severe SLE) and 30 healthy subjects. The serum concentration of Mina53 was measured using enzyme-linked immunosorbent assay (ELISA). The expression of Mina53 gene was assessed using real-time PCR method after extracting RNA from isolated peripheral blood mononuclear cells and synthesizing cDNA. Results: Patients with SLE showed significant increases in the serum level and gene expression of Mina53 compared to healthy subjects (P<0.001). Furthermore, serum level and gene expression of Mina53 showed significant effects on SLE disease and its severity (P<0.01). There was the highest sensitivity and maximum specificity in the cut-off point of Mina53 serum level equal to 125.4 (area under the curve (AUC)=0.951) and Mina53 expression level equal to 8.5 (AUC=0.88) for SLE diagnosis. The cut-off point of Mina53 serum level equal to 139.5 (AUC=0.854) and the cut-off point of Mina53 expression level equal to 8.5 (AUC=0.788) had the highest sensitivity and maximum specificity determining severe forms of SLE. Discussion: Our results showed that the changes in serum and expression levels of Mina53 have significant effects on SLE disease and its severity. These levels may be considered as diagnostic and predictive markers for SLE.

Autoimmune uveitis attenuated in diabetic mice through imbalance of Th1/Th17 differentiation via suppression of AP-1 signaling pathway in Th cells.

Purpose: Inflammation is involved in the pathogenesis of diabetes, however the impact of diabetes on organ-specific autoimmune diseases remains unexplored. Experimental autoimmune uveoretinitis (EAU) is a widely accepted animal model of human endogenous uveitis. In this study, we investigated the effects of diabetic conditions on the development of EAU using a mouse diabetes model. Methods: EAU was induced in wild-type C57BL/6 (WT) mice and Ins2Akita (Akita) mice with spontaneous diabetes by immunization with IRBP peptide. Clinical and histopathological examinations, and analysis of T cell activation state were conducted. In addition, alternations in the composition of immune cell types and gene expression profiles of relevant immune functions were identified using single-cell RNA sequencing. Results: The development of EAU was significantly attenuated in immunized Akita (Akita-EAU) mice compared with immunized WT (WT-EAU) mice, although T cells were fully activated in Akita-EAU mice, and the differentiation into Th17 cells and regulatory T (Treg) cells was promoted. However, Th1 cell differentiation was inhibited in Akita-EAU mice, and single-cell analysis indicated that gene expression associated AP-1 signaling pathway (JUN, FOS, and FOSB) was downregulated not only in Th1 cells but also in Th17, and Treg cells in Akita-EAU mice at the onset of EAU. Conclusions: In diabetic mice, EAU was significantly attenuated. This was related to selective inhibition of Th1 cell differentiation and downregulated AP-1 signaling pathway in both Th1 and Th17 cells.

Tumor-Infiltrating T Cells in Skin Basal Cell Carcinomas and Squamous Cell Carcinomas: Global Th1 Preponderance with Th17 Enrichment-A Cross-Sectional Study.

Basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) are high-incidence, non-melanoma skin cancers (NMSCs). The success of immune-targeted therapies in advanced NMSCs led us to anticipate that NMSCs harbored significant populations of tumor-infiltrating lymphocytes with potential anti-tumor activity. The main aim of this study was to characterize T cells infiltrating NMSCs. Flow cytometry and immunohistochemistry were used to assess, respectively, the proportions and densities of T cell subpopulations in BCCs (n = 118), SCCs (n = 33), and normal skin (NS, n = 30). CD8+ T cells, CD4+ T cell subsets, namely, Th1, Th2, Th17, Th9, and regulatory T cells (Tregs), CD8+ and CD4+ memory T cells, and γδ T cells were compared between NMSCs and NS samples. Remarkably, both BCCs and SCCs featured a significantly higher Th1/Th2 ratio (~four-fold) and an enrichment for Th17 cells. NMSCs also showed a significant enrichment for IFN-γ-producing CD8+T cells, and a depletion of γδ T cells. Using immunohistochemistry, NMSCs featured denser T cell infiltrates (CD4+, CD8+, and Tregs) than NS. Overall, these data favor a Th1-predominant response in BCCs and SCCs, providing support for immune-based treatments in NMSCs. Th17-mediated inflammation may play a role in the progression of NMSCs and thus become a potential therapeutic target in NMSCs.

Rocaglamide promotes infiltration and differentiation of T cells and coordinates with PD-1 inhibitor to overcome checkpoint resistance in multiple tumor models.

Tumor-infiltrating lymphocyte (TIL) deficiency is the most conspicuous obstacle to limit the cancer immunotherapy. Immune checkpoint inhibitors (ICIs), such as anti-PD-1 antibody, have achieved great success in clinical practice. However, due to the limitation of response rates of ICIs, some patients fail to benefit from monotherapy. Thus, novel combination therapy that could improve the response rates emerges as new strategies for cancer treatment. Here, we reported that the natural product rocaglamide (RocA) increased tumor-infiltrating T cells and promoted Th17 differentiation of CD4+ TILs. Despite RocA monotherapy upregulated PD-1 expression of TILs, which was considered as the consequence of T cell activation, combining RocA with anti-PD-1 antibody significantly downregulated the expression of PD-1 and promoted proliferation of TILs. Taken together, these findings demonstrated that RocA could fuel the T cell anti-tumor immunity and revealed the remarkable potential of RocA as a therapeutic candidate when combining with the ICIs.

Smoking and osteoimmunology: Understanding the interplay between bone metabolism and immune homeostasis.

Smoking continues to pose a global threat to morbidity and mortality in populations. The detrimental impact of smoking on health and disease includes bone destruction and immune disruption in various diseases. Osteoimmunology, which explores the communication between bone metabolism and immune homeostasis, aims to reveal the interaction between the osteoimmune systems in disease development. Smoking impairs the differentiation of mesenchymal stem cells and osteoblasts in bone formation while promoting osteoclast differentiation in bone resorption. Furthermore, smoking stimulates the Th17 response to increase inflammatory and osteoclastogenic cytokines that promote the receptor activator of NF-κB ligand (RANKL) signaling in osteoclasts, thus exacerbating bone destruction in periodontitis and rheumatoid arthritis. The pro-inflammatory role of smoking is also evident in delayed bone fracture healing and osteoarthritis development. The osteoimmunological therapies are promising in treating periodontitis and rheumatoid arthritis, but further research is still required to block the smoking-induced aggravation in these diseases. Translational potential: This review summarizes the adverse effect of smoking on mesenchymal stem cells, osteoblasts, and osteoclasts and elucidates the smoking-induced exacerbation of periodontitis, rheumatoid arthritis, bone fracture healing, and osteoarthritis from an osteoimmune perspective. We also propose the therapeutic potential of osteoimmunological therapies for bone destruction aggravated by smoking.

TIGIT Stimulation Suppresses Autoimmune Uveitis by Inhibiting Th17 Cell Infiltration.

T cell immunoglobulin and ITIM domain (TIGIT) is an immune checkpoint molecule that suppresses T cell activation and promotes an immunosuppressive environment to suppress autoimmune diseases. However, the impact of a TIGIT agonist as a treatment for ocular autoimmune disease has not been investigated. We examined TIGIT expression on Th17 and Treg cells, the role of TIGIT on experimental autoimmune uveitis (EAU) and Th17 cells, and the impact of Treg generation following TIGIT stimulation. TIGIT stimulation at the onset of clinical symptoms reduced the severity of uveitis and suppressed infiltration of Th17 cells into the eye. Further, Tregs from mice treated with the TIGIT agonist were capable of suppressing EAU in recipient mice. This report demonstrates that stimulation of TIGIT at onset of disease suppresses symptoms and allows for induction of regulatory immunity that provides resistance to uveitis.

Correlation between the dynamic changes of γδT cells, Th17 cells, CD4+CD25+ regulatory T cells in peripheral blood and pharmacological interventions against bleomycin-induced pulmonary fibrosis progression in mice.

The involvement of γδT cells, Th17 cells, and CD4+CD25+ regulatory T cells (Tregs) is crucial in the progression of pulmonary fibrosis (PF), particularly in maintaining immune tolerance and homeostasis. However, the dynamics of these cells in relation to PF progression, especially under pharmacological interventions, remains poorly understood. This study aims to unravel the interplay between the dynamic changes of these cells and the effect of pharmacological agents in a mouse model of PF induced by intratracheal instillation of bleomycin. We analyzed changes in lung histology, lung index, hydroxyproline levels, and the proportions of γδT cells, Th17 cells, and Tregs on the 3rd, 14th, and 28th days following treatment with Neferine, Isoliensinine, Pirfenidone, and Prednisolone. Our results demonstrate that these drugs can partially or dynamically reverse weight loss, decrease lung index and hydroxyproline levels, and ameliorate lung histopathological damage. Additionally, they significantly modulated the abnormal changes in γδT, Th17, and Treg cell proportions. Notably, on day 3, the proportion of γδT cells increased in the Neferine and Prednisolone groups but decreased in the Isoliensinine and Pirfenidone groups, while the proportion of Th17 cells decreased across all treated groups. On day 14, the Neferine group showed an increase in all three cell types, whereas the Pirfenidone group exhibited a decrease. In the Isoliensinine group, γδT and Th17 cells increased, and in the Prednisolone group, only Tregs increased. By day 28, an increase in Th17 cell proportion was observed in all treatment groups, with a decrease in γδT cells noted in the Neferine group. These shifts in cell proportions are consistent with the pathogenesis changes induced by these anti-PF drugs, suggesting a correlation between cellular dynamics and pharmacological interventions in PF progression. Our findings imply potential strategies for assessing the efficacy and timing of anti-PF treatments based on these cellular changes.