Activin-A limits Th17 pathogenicity and autoimmune neuroinflammation via CD39 and CD73 ectonucleotidases and Hif1-α-dependent pathways

mTOR promotes an inflammatory response through the HIF1 signaling pathway in ulcerative colitis

The imbalance between T helper cell 17 （Th17）and regulatory T cells (Treg) cells leading to inflammation has an important role in the pathogenesis of ulcerative colitis (UC). Mammalian target of rapamycin (mTOR) can regulate the differentiation of T cells, but the specific pathway leading mTOR to regulate Th17/Treg cells in UC remains unclear. Our aim with this study was to investigate the effects of mTOR overexpression and silencing on the hypoxia inducible factor-1α (HIF-1α) - Th17/Treg signaling pathway. To mimic a human study, we established a colon cancer epithelial cell line (HT-29) co-culture system with human CD4+ T cells, and we treated the cells with TNF-α. We observed the effects of mTOR on the HIF-Th17/Treg signaling pathway to determine whether mTOR is involved in the regulatory mechanism. Under the stimulation of TNF-α, the levels of HIF-1α in CD4+T cells were increased in the HT-29 co-culture with CD4+ T cells, promoting glycolysis, increasing the Th17 proportion, decreasing the Treg proportion, increasing the pro-inflammatory factors levels, and decreasing the anti-inflammatory factors levels. Moreover, after mTOR silencing, the HIF-1α level and cell glycolysis levels decreased, Th17 cell differentiation decreased, the pro-inflammatory factor levels decreased, and the anti-inflammatory factor levels increased. In contrast, mTOR overexpression lead to the opposite results.mTOR promotes inflammation by regulating the HIF signaling pathway during UC, and silencing mTOR may alleviate inflammation. An mTOR inhibitor is a potential therapeutic target for UC treatment.

Role of transforming growth factor-β in peripheral nerve regeneration

Injuries caused by trauma and neurodegenerative diseases can damage the peripheral nervous system and cause functional deficits. Unlike in the central nervous system, damaged axons in peripheral nerves can be induced to regenerate in response to intrinsic cues after reprogramming or in a growth-promoting microenvironment created by Schwann cells. However, axon regeneration and repair do not automatically result in the restoration of function, which is the ultimate therapeutic goal but also a major clinical challenge. Transforming growth factor (TGF) is a multifunctional cytokine that regulates various biological processes including tissue repair, embryo development, and cell growth and differentiation. There is accumulating evidence that TGF-β family proteins participate in peripheral nerve repair through various factors and signaling pathways by regulating the growth and transformation of Schwann cells; recruiting specific immune cells; controlling the permeability of the blood-nerve barrier, thereby stimulating axon growth; and inhibiting remyelination of regenerated axons. TGF-β has been applied to the treatment of peripheral nerve injury in animal models. In this context, we review the functions of TGF-β in peripheral nerve regeneration and potential clinical applications.

Extracellular vesicles set the stage for brain plasticity and recovery by multimodal signalling

Extracellular vesicles (EVs) are extremely versatile naturally occurring membrane particles that convey complex signals between cells. EVs of different cellular sources are capable of inducing striking therapeutic responses in neurological disease models. Differently from pharmacological compounds that act by modulating defined signalling pathways, EV-based therapeutics possess multiple abilities via a variety of effectors, thus allowing the modulation of complex disease processes that may have very potent effects on brain tissue recovery. When applied in vivo in experimental models of neurological diseases, EV-based therapeutics have revealed remarkable effects on immune responses, cell metabolism and neuronal plasticity. This multimodal modulation of neuroimmune networks by EVs profoundly influences disease processes in a highly synergistic and context-dependent way. Ultimately, the EV-mediated restoration of cellular functions helps to set the stage for neurological recovery. With this review we first outline the current understanding of the mechanisms of action of EVs, describing how EVs released from various cellular sources identify their cellular targets and convey signals to recipient cells. Then, mechanisms of action applicable to key neurological conditions such as stroke, multiple sclerosis and neurodegenerative diseases are presented. Pathways that deserve attention in specific disease contexts are discussed. We subsequently showcase considerations about EV biodistribution and delineate genetic engineering strategies aiming at enhancing brain uptake and signalling. By sketching a broad view of EV-orchestrated brain plasticity and recovery, we finally define possible future clinical EV applications and propose necessary information to be provided ahead of clinical trials. Our goal is to provide a steppingstone that can be used to critically discuss EVs as next generation therapeutics for brain diseases.

Chemoprophylaxis Effect of EGCG on the Recurrence of Colorectal Cancer: A Systematic Review and Meta-Analysis

BACKGROUND AND AIMS

The recurrence rate of Colorectal Cancer (CRC) after cure is always high. The purpose of this study was to investigate whether green tea extract (-)-Epigallocatechin gallate (EGCG) has an effective preventive effect on the recurrence of CRC.

METHODS

We conducted a systematic literature review and meta-analysis of the effects of taking EGCG or placebo on disease recurrence in patients after colon polyp removal.

RESULTS

Five Randomized Controlled Trials (RCTs) were included in this review. A double-blind drug trial involving 1389 participants involved EGCG and placebo. The results showed no significant publication bias or heterogeneity in the five studies (I2 = 38%; p = 0.17). Patients taking EGCG had a lower recurrence rate of CRC than those in the placebo group. The results were statistically significant (Z=2.83, p < 0.05).

CONCLUSION

This study demonstrated that long-term EGCG can prevent CRC recurrence to a certain extent.

Oral administration of procyanidin B2 3,3"-di-O-gallate ameliorates experimental autoimmune encephalomyelitis through immunosuppressive effects on CD4+ T cells by regulating glycolysis

Multiple Sclerosis (MS) is a chronic autoimmune disease of the central nervous system caused by the excessive activation of T cells. Procyanidins are polyphenols that exhibit anti-inflammatory activity. Procyanidin B2 (PCB2) gallate [specifically, PCB2 3,3″-di-O-gallate (PCB2DG)] inhibits cytokine production in T cells by suppressing the acceleration of glycolysis. In this study, we determined the effect of PCB2DG on T cell-mediated autoimmune disease in vivo. We examined the immunosuppressive effects of PCB2DG using an experimental autoimmune encephalomyelitis (EAE) model, which is a classic animal model for MS. Our results indicated that the clinical score for EAE symptoms improved significantly following the oral administration of PCB2DG. This effect was associated with the suppression of T cell-mediated cytokines (e.g., IFN-γ, TNF-α, and IL-17) and infiltrating T cells into the spinal cord, which ameliorated spinal cord injury. In addition, spleen cell culture experiments revealed that the increase of T cell-mediated pro-inflammatory cytokines in EAE mice was significantly decreased following PCB2DG treatment. We further analyzed the glycolytic activity of spleen cells to identify the mechanism of the immunosuppressive effects of PCB2DG. The production of lactate and the expression of glycolytic enzymes and transporters were increased following EAE induction, but not in PCB2DG-treated EAE mice. Collectively, our results indicate that a dietary polyphenol, which has a unique structure, improves the onset of EAE symptoms and inhibits the excessive activation of T cells by influencing glycolysis.

TH17 cell immune adaptation

At mucosal barriers, the T helper 17 (T_H17) cell population plays a fundamental role in controlling tissue homeostasis. The adaptability of this population to a more pro-inflammatory or anti-inflammatory function - that is, their functional plasticity and consequently heterogeneity - primarily depends on the environment. We would like to term this process environmental immune adaptation. Interfering with T_H17 cell adaptation leads to pathological consequences, including development of immune-mediated inflammatory diseases or even cancer. Several molecular mechanisms have been shown to participate in this process and recently, a better understanding of the transcriptional and metabolic profiling of T_H17 cells has shed light on a new level of complexity. Here, we offer a summary on the role of T_H17 cell plasticity in inflammatory diseases and cancer as well as the latest discoveries and controversies regarding the mechanisms that control the adaptability of the T_H17 cell population.

Different Immunoregulation Roles of Activin A Compared With TGF-β

Activin A, a critical member of the transforming growth factor-β (TGF-β) superfamily, is a pluripotent factor involved in allergies, autoimmune diseases, cancers and other diseases with immune disorder. Similar to its family member, TGF-β, activin A also transmits signals through SMAD2/SMAD3, however, they bind to distinct receptors. Recent studies have uncovered that activin A plays a pivotal role in both innate and adaptive immune systems. Here we mainly focus its effects on activation, differentiation, proliferation and function of cells which are indispensable in the immune system and meanwhile make some comparisons with those of TGF-β.

Excessive immunosuppression by regulatory T cells antagonizes T cell response to schistosome infection in PD-1-deficient mice

Schistosomiasis is caused by parasitic flatworms known as schistosomes and affects over 200 million people worldwide. Prevention of T cell exhaustion by blockade of PD-1 results in clinical benefits to cancer patients and clearance of viral infections, however it remains largely unknown whether loss of PD-1 could prevent or cure schistosomiasis in susceptible mice. In this study, we found that S. japonicum infection dramatically induced PD-1 expression in T cells of the liver where the parasites chronically inhabit and elicit deadly inflammation. Even in mice infected by non-egg-producing unisex parasites, we still observed potent induction of PD-1 in liver T cells of C57BL/6 mice following S. japonicum infection. To determine the function of PD-1 in schistosomiasis, we generated PD-1-deficient mice by CRISPR/Cas9 and found that loss of PD-1 markedly increased T cell count in the liver and spleen of infected mice. IL-4 secreting Th2 cells were significantly decreased in the infected PD-1-deficient mice whereas IFN-γ secreting CD4⁺ and CD8⁺ T cells were markedly increased. Surprisingly, such beneficial changes of T cell response did not result in eradication of parasites or in lowering the pathogen burden. In further experiments, we found that loss of PD-1 resulted in both beneficial T cell responses and amplification of regulatory T cells that prevented PD-1-deficient T cells from unleashing anti-parasite activity. Moreover, such PD-1-deficient Tregs exert excessive immunosuppression and express larger amounts of adenosine receptors CD39 and CD73 that are crucial for Treg-mediated immunosuppression. Our experimental results have elucidated the function of PD-1 in schistosomiasis and provide novel insights into prevention and treatment of schistosomiasis on the basis of modulating host adaptive immunity.

Chronic schistosome infection leads to exaggerated upregulation of PD-1 in the liver, and loss of PD-1 markedly increased T cell presence in the liver of schistosome infected mice, which was accompanied by suppressed Th2 cytokines but markedly increased IFN-γ secretion in CD4⁺ and CD8⁺ T cells. The beneficial T cell response did not result in eradication of parasites or lowering the pathogen burden. Loss of PD-1 also resulted in amplification of Tregs and excessive Treg-mediated immunosuppression may prevent T cells from unleashing anti-parasitic immunity.

Targeting Th17 cells in HIV-1 remission/cure interventions

Since the discovery of HIV-1, progress has been made in deciphering the viral replication cycle and mechanisms of host-pathogen interactions that has facilitated the implementation of effective antiretroviral therapies (ARTs). Major barriers to HIV-1 remission/cure include the persistence of viral reservoirs (VRs) in long-lived CD4⁺ T cells, residual viral transcription, and lack of mucosal immunity restoration during ART, which together fuel systemic inflammation. Recently, T helper (Th)17-polarized cells were identified as major contributors to the pool of transcriptionally/translationally competent VRs. In this review, we discuss the functional features of Th17 cells that were elucidated by fundamental immunology studies in the context of autoimmunity. We also highlight recent discoveries supporting the possibility of extrapolating this knowledge toward the identification of new putative Th17-targeted HIV-1 remission/cure strategies.

TFEB signaling attenuates NLRP3-driven inflammatory responses in severe asthma

BACKGROUND

NLRP3-driven inflammatory responses by circulating and lung-resident monocytes are critical drivers of asthma pathogenesis. Autophagy restrains NLRP3-induced monocyte activation in asthma models. Yet, the effects of autophagy and its master regulator, transcription factor EB (TFEB), on monocyte responses in human asthma remain unexplored. Here, we investigated whether activation of autophagy and TFEB signaling suppress inflammatory monocyte responses in asthmatic individuals.

METHODS

Peripheral blood CD14⁺ monocytes from asthmatic patients (n = 83) and healthy controls (n = 46) were stimulated with LPS/ATP to induce NLRP3 activation with or without the autophagy inducer, rapamycin. ASC specks, caspase-1 activation, IL-1β and IL-18 levels, mitochondrial function, ROS release, and mTORC1 signaling were examined. Autophagy was evaluated by LC3 puncta formation, p62/SQSTM1 degradation and TFEB activation. In a severe asthma (SA) model, we investigated the role of NLRP3 signaling using Nlrp3^-/- mice and/or MCC950 administration, and the effects of TFEB activation using myeloid-specific TFEB-overexpressing mice or administration of the TFEB activator, trehalose.

RESULTS

We observed increased NLRP3 inflammasome activation, concomitant with impaired autophagy in circulating monocytes that correlated with asthma severity. SA patients also exhibited mitochondrial dysfunction and ROS accumulation. Autophagy failed to inhibit NLRP3-driven monocyte responses, due to defective TFEB activation and excessive mTORC1 signaling. NLRP3 blockade restrained inflammatory cytokine release and linked airway disease. TFEB activation restored impaired autophagy, attenuated NLRP3-driven pulmonary inflammation, and ameliorated SA phenotype.

CONCLUSIONS

Our studies uncover a crucial role for TFEB-mediated reprogramming of monocyte inflammatory responses, raising the prospect that this pathway can be therapeutically harnessed for the management of SA.

CD161 expression and regulation defines rapidly responding effector CD4+ T cells associated with improved survival in HPV16-associated tumors

BACKGROUND

Expression of killer cell lectin-like receptor B1 (KLRB1), the gene encoding the cell surface molecule CD161, is associated with favorable prognosis in many cancers. CD161 is expressed by several lymphocyte populations, but its role and regulation on tumor-specific CD4+ T cells is unknown.

METHODS

We examined the clinical impact of CD4+CD161+ T cells in human papillomavirus (HPV)16+ oropharyngeal squamous cell carcinoma (OPSCC), analyzed their contribution in a cohort of therapeutically vaccinated patients and used HPV16-specific CD4+CD161+ tumor-infiltrating lymphocytes and T cell clones for in-depth mechanistic studies.

RESULTS

Central and effector memory CD4+ T cells express CD161, but only CD4+CD161+ effector memory T cells (Tem) are associated with improved survival in OPSCC. Therapeutic vaccination activates and expands type 1 cytokine-producing CD4+CD161+ effector T cells. The expression of CD161 is dynamic and follows a pattern opposite of the checkpoint molecules PD1 and CD39. CD161 did not function as an immune checkpoint molecule as demonstrated using multiple experimental approaches using antibodies to block CD161 and gene editing to knockout CD161 expression. Single-cell transcriptomics revealed KLRB1 expression in many T cell clusters suggesting differences in their activation. Indeed, CD4+CD161+ effector cells specifically expressed the transcriptional transactivator SOX4, known to enhance T cell receptor (TCR) signaling via CD3ε. Consistent with this observation, CD4+CD161+ cells respond more vigorously to limiting amounts of cognate antigen in presence of interleukin (IL)-12 and IL-18 compared to their CD161- counterparts. The expression of CD161/KLRB1 and SOX4 was downregulated upon TCR stimulation and this effect was boosted by transforming growth factor (TGF)β1.

CONCLUSION

High levels of CD4+CD161+ Tem are associated with improved survival and our data show that CD161 is dynamically regulated by cell intrinsic and extrinsic factors. CD161 expressing CD4+ T cells rapidly respond to suboptimal antigen stimulation suggesting that CD161, similar to SOX4, is involved in the amplification of TCR signals in CD4+ T cells.

Activin-A impedes the establishment of CD4+ T cell exhaustion and enhances anti-tumor immunity in the lung

Background

Although tumor-infiltrating T cells represent a favorable prognostic marker for cancer patients, the majority of these cells are rendered with an exhausted phenotype. Hence, there is an unmet need to identify factors which can reverse this dysfunctional profile and restore their anti-tumorigenic potential. Activin-A is a pleiotropic cytokine, exerting a broad range of pro- or anti-inflammatory functions in different disease contexts, including allergic and autoimmune disorders and cancer. Given that activin-A exhibits a profound effect on CD4⁺ T cells in the airways and is elevated in lung cancer patients, we hypothesized that activin-A can effectively regulate anti-tumor immunity in lung cancer.

Methods

To evaluate the effects of activin-A in the context of lung cancer, we utilized the OVA-expressing Lewis Lung Carcinoma mouse model as well as the B16F10 melanoma model of pulmonary metastases. The therapeutic potential of activin-A-treated lung tumor-infiltrating CD4⁺ T cells was evaluated in adoptive transfer experiments, using CD4^−/−-tumor bearing mice as recipients. In a reverse approach, we disrupted activin-A signaling on CD4⁺ T cells using an inducible model of CD4⁺ T cell-specific knockout of activin-A type I receptor. RNA-Sequencing analysis was performed to assess the transcriptional signature of these cells and the molecular mechanisms which mediate activin-A’s function. In a translational approach, we validated activin-A’s anti-tumorigenic properties using primary human tumor-infiltrating CD4⁺ T cells from lung cancer patients.

Results

Administration of activin-A in lung tumor-bearing mice attenuated disease progression, an effect associated with heightened ratio of infiltrating effector to regulatory CD4⁺ T cells. Therapeutic transfer of lung tumor-infiltrating activin-A-treated CD4⁺ T cells, delayed tumor progression in CD4^−/− recipients and enhanced T cell-mediated immunity. CD4⁺ T cells genetically unresponsive to activin-A, failed to elicit effective anti-tumor properties and displayed an exhausted molecular signature governed by the transcription factors Tox and Tox2. Of translational importance, treatment of activin-A on tumor-infiltrating CD4⁺ T cells from lung cancer patients augmented their immunostimulatory capacity towards autologous CD4⁺ and CD8⁺ T cells.

Conclusions

In this study, we introduce activin-A as a novel immunomodulatory factor in the lung tumor microenvironment, which bestows exhausted CD4⁺ T cells with effector properties.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02092-5.

Metabolic rewiring: a new master of Th17 cell plasticity and heterogeneity

T helper type 17 (Th17) cells are characterized by inherent plasticity and heterogeneity displaying both pathogenic and tissue-protective functions. Emerging evidence has illuminated a pivotal role for metabolic reprogramming in shaping Th17 cell fate determination. Metabolic responses are regulated by a constellation of factors and environmental triggers, including cytokines, nutrients, oxygen levels, and metabolites. Dysregulation of metabolic pathways not only influences Th17 cell plasticity and effector function but also affects the outcome of Th17-linked autoimmune, inflammatory, and antitumor responses. Understanding the molecular mechanisms underpinning metabolic reprogramming can allow the enhancement of protective Th17 cell-mediated responses during infections and cancer, concomitant with the suppression of detrimental Th17 processes during autoimmune and inflammatory diseases. In the present review, we describe major metabolic pathways underlying the differentiation of Th17 cells and their crosstalk with intracellular signaling mediators, we discuss how metabolic reprogramming affects Th17 cell plasticity and functions, and, finally, we outline current advances in the exploitation of metabolic checkpoints for the development of novel therapeutic interventions for the management of tissue inflammation, autoimmune disorders, and cancer.

Impact of Maternal Food Restriction on Heart Proteome in Appropriately Grown and Growth-Restricted Wistar-Rat Offspring

Objective: Fetal growth restriction is associated with increased postnatal cardiovascular morbidity. The alterations in heart physiology and structure caused by in utero nutrient deprivation have not been extensively studied. We aim to investigate the impact of maternal food restriction on the cardiac proteome of newborn rats with normal (non-fetal growth-restricted (FGR)) and reduced (FGR) birth weight. Methods: On day 14 of gestation, 10 timed pregnant rats were randomized into two nutritional groups: (a) Standard laboratory diet and (b) 50% global food restriction. Pups born to food-restricted mothers were subdivided, based on birthweight, into fetal growth-restricted (FGR) and non-FGR, while pups born from normally nourished mothers were considered controls. Rat neonates were euthanized immediately after birth and the hearts of 11 randomly selected male offspring (n = 4 FGR, n = 4 non-FGR, n = 3 control group) were analyzed using quantitative proteomics. Results: In total, 7422 proteins were quantified (q < 0.05). Of these, 1175 were differentially expressed in FGR and 231 in non-FGR offspring vs. control with 151 common differentially expressed proteins (DEPs) between the two groups. Bioinformatics analysis of DEPs in FGR vs. control showed decreased integrin and apelin cardiac fibroblast signaling, decreased muscle contraction and glycolysis, and over-representation of a protein network related to embryonic development, and cell death and survival. Conclusion: Our study illustrates the distinct proteomic profile of FGR and non-FGR offspring of food-restricted dams underlying the importance of both prenatal adversities and birth weight in cardiac physiology and development.

Ectonucleotidase Modulation of Lymphocyte Function in Gut and Liver

Imbalance between regulatory and effector T lymphocytes contributes to loss of immunotolerance and plays a permissive role in the initiation, perpetuation, and progression of chronic inflammatory diseases and autoimmune disorders. Regulatory/effector cell balance is governed by the CD39 ectonucleotidase, the prototype member of the NTPDase family that hydrolyzes ATP and ADP into AMP, subsequently converted into adenosine by CD73. Generation of adenosine impacts T-cell function as it contributes to the mechanism of suppression of Tregs and confers regulatory properties to pathogenic Th17-cells. CD39 cell distribution, mechanism of regulation and impact on inflammatory and regulatory signaling pathways are also discussed here. Innovative therapeutic strategies to boost CD39 levels and activity by either administering soluble ADPases or interfering with CD39 inhibitory signals are reviewed. Restoration of CD39 levels and function has enormous translational and clinical implications and should be regarded as an additional form of treatment to be deployed in the chronic inflammatory setting. The key role of CD39 in immunoregulation in the context of Crohn's disease, one of the most frequent manifestations of inflammatory bowel disease, and autoimmune hepatitis, an autoimmune disorder of the liver, is reviewed and discussed here.

The TGF-β superfamily cytokine Activin-A is induced during autoimmune neuroinflammation and drives pathogenic Th17 cell differentiation

Th17 cells are known to exert pathogenic and non-pathogenic functions. Although the cytokine transforming growth factor β1 (TGF-β1) is instrumental for Th17 cell differentiation, it is dispensable for generation of pathogenic Th17 cells. Here, we examined the T cell-intrinsic role of Activin-A, a TGF-β superfamily member closely related to TGF-β1, in pathogenic Th17 cell differentiation. Activin-A expression was increased in individuals with relapsing-remitting multiple sclerosis and in mice with experimental autoimmune encephalomyelitis. Stimulation with interleukin-6 and Activin-A induced a molecular program that mirrored that of pathogenic Th17 cells and was inhibited by blocking Activin-A signaling. Genetic disruption of Activin-A and its receptor ALK4 in T cells impaired pathogenic Th17 cell differentiation in vitro and in vivo. Mechanistically, extracellular-signal-regulated kinase (ERK) phosphorylation, which was essential for pathogenic Th17 cell differentiation, was suppressed by TGF-β1-ALK5 but not Activin-A-ALK4 signaling. Thus, Activin-A drives pathogenic Th17 cell differentiation, implicating the Activin-A-ALK4-ERK axis as a therapeutic target for Th17 cell-related diseases.

Tumour Microenvironment: Roles of the Aryl Hydrocarbon Receptor, O-GlcNAcylation, Acetyl-CoA and Melatonergic Pathway in Regulating Dynamic Metabolic Interactions across Cell Types-Tumour Microenvironment and Metabolism

This article reviews the dynamic interactions of the tumour microenvironment, highlighting the roles of acetyl-CoA and melatonergic pathway regulation in determining the interactions between oxidative phosphorylation (OXPHOS) and glycolysis across the array of cells forming the tumour microenvironment. Many of the factors associated with tumour progression and immune resistance, such as yin yang (YY)1 and glycogen synthase kinase (GSK)3β, regulate acetyl-CoA and the melatonergic pathway, thereby having significant impacts on the dynamic interactions of the different types of cells present in the tumour microenvironment. The association of the aryl hydrocarbon receptor (AhR) with immune suppression in the tumour microenvironment may be mediated by the AhR-induced cytochrome P450 (CYP)1b1-driven 'backward' conversion of melatonin to its immediate precursor N-acetylserotonin (NAS). NAS within tumours and released from tumour microenvironment cells activates the brain-derived neurotrophic factor (BDNF) receptor, TrkB, thereby increasing the survival and proliferation of cancer stem-like cells. Acetyl-CoA is a crucial co-substrate for initiation of the melatonergic pathway, as well as co-ordinating the interactions of OXPHOS and glycolysis in all cells of the tumour microenvironment. This provides a model of the tumour microenvironment that emphasises the roles of acetyl-CoA and the melatonergic pathway in shaping the dynamic intercellular metabolic interactions of the various cells within the tumour microenvironment. The potentiation of YY1 and GSK3β by O-GlcNAcylation will drive changes in metabolism in tumours and tumour microenvironment cells in association with their regulation of the melatonergic pathway. The emphasis on metabolic interactions across cell types in the tumour microenvironment provides novel future research and treatment directions.

Cytokine-regulated Th17 plasticity in human health and diseases

Upon activation, naïve CD4⁺ T helper (Th) cells differentiate into distinct Th effector cell lineages depending on the local cytokine environment. However, these polarized Th cells can also adapt their function and phenotype depending on the changing cytokine environment, demonstrating functional plasticity. Here, Th17 cells, which play a critical role in host protection from extracellular pathogens and in autoimmune disorders, are of particular interest. While being able to shift phenotype within their lineage, Th17 cells can also acquire characteristics of Th1, Th2, T follicular helper (Tfh) or regulatory T cells. Th17 cell identity is determined by a spectrum of extracellular signals, including cytokines, which are critical orchestrators of cellular immune responses. Cytokine induces changes in epigenetic, transcriptional, translational and metabolomic parameters. How these signals are integrated to determine Th17 plasticity is not well defined, yet this is a crucial point of investigation as it represents a potential target to treat autoimmune and inflammatory diseases. The goal of this review was to discuss how cytokines regulate intracellular networks, focusing on the regulation of lineage-specific transcription factors, chromatin remodelling and metabolism, to control human Th17 cell plasticity. We discuss the importance of Th17 plasticity in autoimmunity and cancer and present current strategies and challenges in targeting pathogenic Th17 cells with cytokine-based approaches, considering human genetic variants associated with altered Th17 differentiation. Finally, we discuss how modulating Th17 plasticity rather than targeting the Th17 lineage as a whole might preserve its essential immune function while purging its adverse effects.

Upregulation of miR-9 and miR-193b over human Th17 cell differentiation

BACKGROUND

Th17 cells are a newly discovered subset of CD4⁺ T cells known as key participants in various immune responses and inflammatory conditions including autoimmune diseases. Mi(cro)RNAs are a family of non-coding RNAs that regulate numerous critical immune functions. Immuno-miRNAs modulate cell biological processes in T cells, such as differentiation and function of Th17 cells. The aim of the present study is to investigate the expression of miR-9-5p, miR-193b-3p, and autoimmunity-related genes during human Th17 cells differentiation.

METHODS

Human naïve CD4⁺ T cells were purified from peripheral blood mononuclear cells (PBMCs) by magnetic cell sorting system (MACS) and their purity was checked by flow-cytometric analysis. Naïve CD4⁺ T cells were cultured under Th17-polarizing condition for 6 days. IL- 17 secretion was determined by means of enzyme-linked immunosorbent assay (ELISA). Next, the expression levels of miRNAs and putative targets genes were assessed by qRT-PCR at different time points of differentiation.

RESULTS

Our result showed dramatic downregulation of TCF7, MAP3K1, ENTPD1, and NT5E genes during human Th17 differentiation. Polarization also had a significant inducible effect on the expression of miR-9 and miR-193b over differentiation of human Th17 cells. According to our results, miR-9-5p and miR-193b-3p may contribute to Th17 differentiation probably by inhibiting the expression of negative regulators of Th17 differentiation.

CONCLUSION

This study confirmed deregulation of TCF7, MAP3K1, ENTPD1, and NT5E genes in Th17 differentiation process and introduced miR-9 and miR-193b as Th17 cell-associated miRNAs, making them good candidates for further investigations.