TNF-α blockade induces IL-10 expression in human CD4+ T cells

Investigating the pro-inflammatory differentiation of macrophages with bacterial ghosts in potential infection control

In the complex realm of bacterial infections, particularly those caused by Staphylococcus aureus (S. aureus), macrophages play a pivotal role in orchestrating the immune response. During the initial stages of infection, the monocytes give rise to macrophages with a pro-inflammatory (M1 type) behaviour, engulfing and neutralizing the invading pathogens. However, under the sustained influence of S. aureus infection, monocytes can undergo a transition into an anti-inflammatory M2 state (pro-infection) rather than the M1 state (anti-infection), thereby compromising effective infection control. Therefore, it is necessary to develop a strategy that would preserve the pro-inflammatory functions of macrophages, in a safe and controlled manner. For this, we focused on harnessing the potential of S. aureus-derived ghost cells (GCs) which are non-live empty envelopes of bacterial cells, but with the antigenic determinants intact. Through a unique Lugol's-iodine treatment, we generated GCs and characterization of these GCs using gel electrophoresis, FTIR, flow cytometry, TEM, and SEM confirmed their structural integrity. Following this, we assessed the extend of cellular association of the GCs with RAW267.4 macrophages, and observed an immediate interaction between the two, as evident from the flowcytometry and microscopy studies. We then performed macrophage polarisation on a human monocyte-macrophage model cell line, THP-1. Our findings revealed that GCs effectively activated macrophages, and promoted a pro-inflammatory polarisation with the expression of M1 differentiation markers (CD86, TNFα, IL-1β, IL-6, IL-12) evaluated through both qPCR and ELISA. Interestingly an intermediary expression of M2 markers viz., CD206 and IL-10 was also observed, but was overruled by the enhanced expression of M1 markers at a later time point. Overall, our study introduces a novel approach utilizing GCs to guide naïve macrophages towards M1 subtypes, thereby potentiating immune responses during microbial infections. This innovative strategy can modulate macrophage function, ultimately improving outcomes in S. aureus infections and beyond.

A H₂S-Evolving Alternately-Catalytic Enzyme Bio-Heterojunction with Antibacterial and Macrophage-Reprogramming Activity for All-Stage Infectious Wound Regeneration

The disorder of the macrophage phenotype and the hostile by-product of lactate evoked by pathogenic infection in hypoxic deep wound inevitably lead to the stagnant skin regeneration. In this study, hydrogen sulfide (H2S)-evolving alternately catalytic bio-heterojunction enzyme (AC-BioHJzyme) consisting of CuFe2S3 and lactate oxidase (LOD) named as CuFe2S3@LOD is developed. AC-BioHJzyme exhibits circular enzyme-mimetic antibacterial (EMA) activity and macrophage re-rousing capability, which can be activated by near-infrared-II (NIR-II) light. In this system, LOD exhausts lactate derived from bacterial anaerobic respiration and generated hydrogen peroxide (H2O2), which provides an abundant stock for the peroxidase-mimetic activity to convert the produced H2O2 into germicidal •OH. The GPx-mimetic activity endows AC-BioHJzyme with a glutathione consumption property to block the antioxidant systems in bacterial metabolism, while the O2 provided by the CAT-mimetic activity can generate 1O2 under the NIR-II irradiation. Synchronously, the H2S gas liberated from CuFe2S3@LOD under the infectious micromilieu allows the reduction of Fe(III)/Cu(II) to Fe(II)/Cu(І), resulting in sustained circular EMA activity. In vitro and in vivo assays indicate that the CuFe2S3@LOD AC-BioHJzyme significantly facilitates the infectious cutaneous regeneration by killing bacteria, facilitating epithelialization/collagen deposition, promoting angiogenesis, and reprogramming macrophages. This study provides a countermeasure for deep infectious wound healing via circular enzyme-mimetic antibiosis and macrophage re-rousing.

AIOLOS-Associated Inborn Errors of Immunity

AIOLOS, encoded by the IKZF3 gene, belongs to the Ikaros zinc finger transcription factor family and plays a pivotal role in regulating lymphocyte development. Recently, heterozygous missense loss-of-function variants within the DNA-binding domain of the IKZF3 gene (G159R, N160S, and G191R) have been identified in patients with inborn errors of immunity (IEI). Additionally, a missense and a truncating variant (E82K and Q402X) leading to the AIOLOS haploinsufficiency have been documented. The majority of individuals with AIOLOS-associated IEI manifest recurrent sinopulmonary infections, as well as various bacterial and viral infections. The patients carrying the AIOLOSN160S variant exhibit severe immunodeficient phenotypes. In contrast, patients harboring AIOLOS haploinsufficient variants predominantly present with clinical phenotypes associated with immune dysregulation. A varying degree of B-lymphopenia and hypoimmunoglobulinemia was noted in approximately half of the patients. Mouse models of AIOLOSG159R and AIOLOSN160S variants (AiolosG158R and AiolosN159S in mice, respectively) recapitulated most of the immune abnormalities observed in the patients. Among these models, AiolosG158R mice prominently exhibited defects in early B cell differentiation resulting from mutant Aiolos interfering with Ikaros function through heterodimer formation. In contrast, AiolosN159S mice did not manifest early B cell differentiation defects. However, they displayed a distinct immune abnormality characterized by impaired induction of CD62L expression in lymphocytes, which is likely attributable to dysfunction of Ikaros, leading to defective lymphocyte homing to lymph nodes. Considering the diverse clinical phenotypes observed in the reported cases and the distinct molecular pathogenesis associated with each variant, further studies with more patients with AIOLOS-associated IEI would contribute to a better understanding of the clinical spectrum and underlying molecular mechanisms associated with this disorder.

Regulation of Treg cells by cytokine signaling and co-stimulatory molecules

CD4+CD25+Foxp3+ regulatory T cells (Tregs), a vital component of the immune system, are responsible for maintaining immune homeostasis and preventing excessive immune responses. This review explores the signaling pathways of the cytokines that regulate Treg cells, including transforming growth factor beta (TGF-β), interleukin (IL)-2, IL-10, and IL-35, which foster the differentiation and enhance the immunosuppressive capabilities of Tregs. It also examines how, conversely, signals mediated by IL-6 and tumor necrosis factor -alpha (TNF-α) can undermine Treg suppressive functions or even drive their reprogramming into effector T cells. The B7 family comprises indispensable co-stimulators for T cell activation. Among its members, this review focuses on the capacity of CTLA-4 and PD-1 to regulate the differentiation, function, and survival of Tregs. As Tregs play an essential role in maintaining immune homeostasis, their dysfunction contributes to the pathogenesis of autoimmune diseases. This review delves into the potential of employing Treg-based immunotherapy for the treatment of autoimmune diseases, transplant rejection, and cancer. By shedding light on these topics, this article aims to enhance our understanding of the regulation of Tregs by cytokines and their therapeutic potential for various pathological conditions.

TNF-α signals through ITK-Akt-mTOR to drive CD4+ T cell metabolic reprogramming, which is dysregulated in rheumatoid arthritis

Upon activation, T cells undergo metabolic reprogramming to meet the bioenergetic demands of clonal expansion and effector function. Because dysregulated T cell cytokine production and metabolic phenotypes coexist in chronic inflammatory disease, including rheumatoid arthritis (RA), we investigated whether inflammatory cytokines released by differentiating T cells amplified their metabolic changes. We found that tumor necrosis factor-α (TNF-α) released by human naïve CD4+ T cells upon activation stimulated the expression of a metabolic transcriptome and increased glycolysis, amino acid uptake, mitochondrial oxidation of glutamine, and mitochondrial biogenesis. The effects of TNF-α were mediated by activation of Akt-mTOR signaling by the kinase ITK and did not require the NF-κB pathway. TNF-α stimulated the differentiation of naïve cells into proinflammatory T helper 1 (TH1) and TH17 cells, but not that of regulatory T cells. CD4+ T cells from patients with RA showed increased TNF-α production and consequent Akt phosphorylation upon activation. These cells also exhibited increased mitochondrial mass, particularly within proinflammatory T cell subsets implicated in disease. Together, these findings suggest that T cell-derived TNF-α drives their metabolic reprogramming by promoting signaling through ITK, Akt, and mTOR, which is dysregulated in autoinflammatory disease.

TH17 cell: a double-edged sword in the development of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic nonspecific inflammatory disease of the gastrointestinal tract, and its pathogenesis has not been fully understood. Extensive dysregulation of the intestinal mucosal immune system is critical in the development and progression of IBD. T helper (Th) 17 cells have the characteristics of plasticity. They can transdifferentiate into subpopulations with different functions in response to different factors in the surrounding environment, thus taking on different roles in regulating the intestinal immune responses. In this review, we will focus on the plasticity of Th17 cells as well as the function of Th17 cells and their related cytokines in IBD. We will summarize their pathogenic and protective roles in IBD under different conditions, respectively, hoping to further deepen the understanding of the pathological mechanisms underlying IBD and provide insights for future treatment.

Identifying immune checkpoint-related lncRNA biomarkers for immunotherapy response and prognosis in cancers

Long non-coding RNAs (lncRNAs) could modulate expression of immune checkpoints (ICPs) in tumor-immune. However, precise functions in immunity and potential for predicting ICP inhibitors (ICI) response have been described for only a few lncRNAs. Here, a multiple-step pipeline was developed to identify cancer- and immune-context ICP and lncRNA cooperative regulation pairs (ICPaLncCRPs) across cancers. Immune-related ICPs and lncRNAs were extracted follow immune cell lines and immunologic constant of rejection groups. ICPaLncCRP networks were constructed, which likely to modulate tumor-immune by specific patterns. Common and specific hub ICPaLncs such as MIR155HG, TRG-AS1 and PCED1B-AS1 maybe play central roles in prognosis and circulating. Moreover, these hub ICPaLncs were significantly correlated with immune cell infiltration based on bulk and single-cell RNA sequencing data. Some ICPaLncCRPs such as IDO1-MIR155HG could predict three- and five-year prognosis of melanoma in two independent datasets. We also validated that some ICPaLncCRPs could effectively predict ICI-response follow six independent datasets. Collectively, this study will enhance our understanding of lncRNA functions and accelerate discovery of lncRNA-based biomarkers in ICI treatment.

Modulation of neurotrophic factors in the treatment of dementia, stroke and TBI: Effects of Cerebrolysin

Neurotrophic factors (NTFs) are involved in the pathophysiology of neurological disorders such as dementia, stroke and traumatic brain injury (TBI), and constitute molecular targets of high interest for the therapy of these pathologies. In this review we provide an overview of current knowledge of the definition, discovery and mode of action of five NTFs, nerve growth factor, insulin-like growth factor 1, brain derived NTF, vascular endothelial growth factor and tumor necrosis factor alpha; as well as on their contribution to brain pathology and potential therapeutic use in dementia, stroke and TBI. Within the concept of NTFs in the treatment of these pathologies, we also review the neuropeptide preparation Cerebrolysin, which has been shown to resemble the activities of NTFs and to modulate the expression level of endogenous NTFs. Cerebrolysin has demonstrated beneficial treatment capabilities in vitro and in clinical studies, which are discussed within the context of the biochemistry of NTFs. The review focuses on the interactions of different NTFs, rather than addressing a single NTF, by outlining their signaling network and by reviewing their effect on clinical outcome in prevalent brain pathologies. The effects of the interactions of these NTFs and Cerebrolysin on neuroplasticity, neurogenesis, angiogenesis and inflammation, and their relevance for the treatment of dementia, stroke and TBI are summarized.

Cadmium exposure caused cardiotoxicity in common carps (Cyprinus carpio L.): miR-9-5p, oxidative stress, energetic impairment, mitochondrial division/fusion imbalance, inflammation, and autophagy

Cadmium (Cd), a toxic heavy metal pollutant, is a threat to human and eatable fish health. Common carps are widely cultivated and eaten by humans. However, there are no reports about Cd-damaged common carp hearts. Our experiment attempted to investigate the cardiotoxicity of Cd to common carps by establishing a common carp Cd exposure model. Our results showed that Cd injured hearts. Moreover, Cd treatment induced autophagy via miR-9-5p/Sirt1/mTOR/ULK1 pathway. Cd exposure caused oxidant/antioxidant imbalance and oxidative stress; and led to energetic impairment. Energetic impairment partook in oxidative stress-mediated autophagy through AMPK/mTOR/ULK1 pathway. Furthermore, Cd caused mitochondrial division/fusion imbalance and resulted in inflammatory injury via NF-κB-COX-2-PTGEs and NF-κB-COX-2-TNF-α pathways. Oxidative stress mediated mitochondrial division/fusion imbalance, further induced inflammation and autophagy via OPA1/NF-κB-COX-2-TNF-α-Beclin1 and OPA1/NF-κB-COX-2-TNF-α/P62 pathways under Cd treatment. Taken together, miR-9-5p, oxidative stress, energetic impairment, mitochondrial division/fusion imbalance, inflammation, and autophagy participated in the mechanism of Cd-cardiotoxicity to common carps. Our study revealed harmful effect of Cd on hearts, and provided new information for researches of environmental pollutant toxicity.

IKZF3 modulates cerebral ischemia/reperfusion injury by inhibiting neuroinflammation

Neuroinflammation is a key mediator to the pathogenic cascades induced by cerebral ischemia-reperfusion (I/R) injury. IKZF3, a key zinc finger transcription factor in the Ikaros family, has already been shown to modulate a wide range of cell functions and the production of inflammatory mediators. However, the effects of IKZF3 on inflammation and the potential mechanism after cerebral I/R injury remain unclear. In this study, we evaluated the effect of IKZF3 on HT-22 cells under oxygen-glucose deprivation and reoxygenation (OGD/R) in vitro and in mice with MACO in vivo. We found that IKZF3 expression peaked at 12 h after MCAO and OGD/R, and there was high expression of IKZF3 in brain tissues and HT-22 cells. IKZF3 knockdown exacerbated the damage by OGD-induced HT-22 cells injury and MCAO-induced brain injury in mice by regulating the production of inflammatory factors, which promoted the phosphorylation and nuclear transfer of NF-ĸB and may bind with NF-ĸB-p65 in vivo and in vitro. Our results suggested that IKZF3 may provide a new target in improve neurological recovery and reducing neuroinflammation after cerebral I/R injury.

Selective inhibition of soluble tumor necrosis factor signaling reduces abdominal aortic aneurysm progression

Background

Tumor necrosis factor (TNF) is pathologically elevated in human abdominal aortic aneurysms (AAA). Non-selective TNF inhibition-based therapeutics are approved for human use but have been linked to several side effects. Compounds that target the proinflammatory soluble form of TNF (solTNF) but preserve the immunomodulatory capabilities of the transmembrane form of TNF (tmTNF) may prevent these side effects. We hypothesize that inhibition of solTNF signaling prevents AAA expansion.

Methods

The effect of the selective solTNF inhibitor, XPro1595, and the non-selective TNF inhibitor, Etanercept (ETN) was examined in porcine pancreatic elastase (PPE) induced AAA mice, and findings with XPro1595 was confirmed in angiotensin II (ANGII) induced AAA in hyperlipidemic apolipoprotein E (Apoe) ^–/– mice.

Results

XPro1595 treatment significantly reduced AAA expansion in both models, and a similar trend (p = 0.06) was observed in PPE-induced AAA in ETN-treated mice. In the PPE aneurysm wall, XPro1595 improved elastin integrity scores. In aneurysms, mean TNFR1 levels reduced non-significantly (p = 0.07) by 50% after TNF inhibition, but the histological location in murine AAAs was unaffected and similar to that in human AAAs. Semi-quantification of infiltrating leucocytes, macrophages, T-cells, and neutrophils in the aneurysm wall were unaffected by TNF inhibition. XPro1595 increased systemic TNF levels, while ETN increased systemic IL-10 levels. In ANGII-induced AAA mice, XPro1595 increased systemic TNF and IL-5 levels. In early AAA development, proteomic analyses revealed that XPro1595 significantly upregulated ontology terms including “platelet aggregation” and “coagulation” related to the fibrinogen complex, from which several proteins were among the top regulated proteins. Downregulated ontology terms were associated with metabolic processes.

Conclusion

In conclusion, selective inhibition of solTNF signaling reduced aneurysm expansion in mice, supporting its potential as an attractive treatment option for AAA patients.

Migration and homeostasis of regulatory T cells in rheumatoid arthritis

Regulatory T (T_reg) cells are garnering increased attention in research related to autoimmune diseases, including rheumatoid arthritis (RA). They play an essential role in the maintenance of immune homeostasis by restricting effector T cell activity. Reduced functions and frequencies of T_reg cells contribute to the pathogenesis of RA, a common autoimmune disease which leads to systemic inflammation and erosive joint destruction. T_reg cells from patients with RA are characterized by impaired functions and by an altered phenotype. They show increased plasticity towards Th17 cells and a reduced suppressive capacity. Besides the suppressive function of T_reg cells, their effectiveness is determined by their ability to migrate into inflamed tissues. In the past years, new mechanisms involved in T_reg cell migration have been identified. One example of such a mechanism is the phosphorylation of vasodilator-stimulated phosphoprotein (VASP). Efficient migration of T_reg cells requires the presence of VASP. IL-6, a cytokine which is abundantly present in the peripheral blood and in the synovial tissue of RA patients, induces posttranslational modifications of VASP. Recently, it has been shown in mice with collagen-induced arthritis (CIA) that this IL-6 mediated posttranslational modification leads to reduced T_reg cell trafficking. Another protein which facilitates T_reg cell migration is G-protein-signaling modulator 2 (GPSM2). It modulates G-protein coupled receptor functioning, thereby altering the cellular activity initiated by cell surface receptors in response to extracellular signals. The almost complete lack of GPSM2 in T_reg cells from RA patients contributes to their reduced ability to migrate towards inflammatory sites. In this review article, we highlight the newly identified mechanisms of T_reg cell migration and review the current knowledge about impaired T_reg cell homeostasis in RA.

Differential genotypes of TNF-α and IL-10 for immunological diagnosis in discoid lupus erythematosus and oral lichen planus: A narrative review

Discoid lupus erythematosus and oral lichen planus are chronic systemic immune system-mediated diseases with unclear etiology and pathogenesis. The oral mucosa is the common primary site of pathogenesis in both, whereby innate and adaptive immunity and inflammation play crucial roles. The clinical manifestations of discoid lupus erythematosus on the oral mucosa are very similar to those of oral lichen planus; therefore, its oral lesion is classified under oral lichenoid lesions. In practice, the differential diagnosis of discoid lupus erythematosus and oral lichen planus has always relied on the clinical manifestations, with histopathological examination as an auxiliary diagnostic tool. However, the close resemblance of the clinical manifestations and histopathology proves challenging for accurate differential diagnosis and further treatment. In most cases, dentists and pathologists fail to distinguish between the conditions during the early stages of the lesions. It should be noted that both are considered to be precancerous conditions, highlighting the significance of early diagnosis and treatment. In the context of unknown etiology and pathogenesis, we suggest a serological and genetic diagnostic method based on TNF-α and IL-10. These are the two most common cytokines produced by the innate and adaptive immune systems and they play a fundamental role in maintaining immune homeostasis and modulating inflammation. The prominent variability in their expression levels and gene polymorphism typing in different lesions compensates for the low specificity of current conventional diagnostic protocols. This new diagnostic scheme, starting from the immunity and inflammation of the oral mucosa, enables simultaneous comparison of discoid lupus erythematosus and oral lichen planus. With relevant supportive evidence, this information can enhance physicians’ understanding of the two diseases, contribute to precision medicine, and aid in prevention of precancerous conditions.

Tumour necrosis factor inhibitor use during pregnancy is associated with increased birth weight of rheumatoid arthritis patients' offspring

OBJECTIVES

To study pregnancy outcomes in a closely monitored, well-defined cohort of women with rheumatoid arthritis (RA). In particular, pregnancy outcomes of women that used a TNFi during pregnancy.

METHODS

Patients were derived from a prospective study on pregnancy and RA (Preconception Counseling in Active RA study) and treated according to a treatment protocol aimed at minimal disease activity. Multivariate linear regression analysis was used to describe which variables influenced birth weight.

RESULTS

188 patients were included, 92 (48.9%) patients with RA used a TNFi during pregnancy. Disease Activity Score in 28 joints C reactive protein (DAS28CRP) was low at all time points during pregnancy (DAS28CRP in the third trimester: 2.17 (SD 0.73). TNFi use was not associated with an increase of adverse pregnancy outcomes such as low birth weight (<2500 g), (emergency) caesarian section, hypertensive disorders or congenital malformations. TNFi use resulted in less children born small-for-gestational age (p=0.05), however, did not increase the risk of large-for-gestational age (p=0.73). Mean birth weight was 173 g higher in women that used a TNFi during pregnancy (3.344 kg vs 3.171 kg, p=0.03). In the multivariate analysis, maternal age (β -0.023, 95% CI -0.040 to -0.0065, p=0.007), TNFi use (β 0.20, 95% CI 0.066, 0.34, p=0.004), diabetes mellitus (β 0.37, 95% CI 0.12, 0.63, p=0.004) and gestational age (β 0.18, 95% CI 0.15, 0.2, p<0.001) were statistically significant associated with birth weight.

CONCLUSIONS

This is the first study to show that TNFi use during pregnancy is associated with increased birth weight of offspring of women with well-controlled RA. The underlying mechanism of TNF-inhibition on birth weight and the long-term consequences for the offspring should be explored in future research.

Regulatory T Cells from Patients with Rheumatoid Arthritis Are Characterized by Reduced Expression of Ikaros Zinc Finger Transcription Factors

Regulatory T (Treg) cells play an important role in immune tolerance and contribute to the prevention of autoimmune diseases, including rheumatoid arthritis (RA). The differentiation, function and stability of Treg cells is controlled by members of the Ikaros zinc finger transcription factor family. In this study, we aimed to reveal how the expression of Ikaros transcription factors is affected by disease activity in RA. Therefore, we analyzed the ex vivo expression of Ikaros, Helios, Aiolos and Eos in Treg cells, Th17 cells and Th1 cells from RA patients by flow cytometry. We found significantly reduced expression of Helios, Aiolos and Eos in Treg cells from RA patients as compared to healthy controls. Moreover, Helios and Aiolos levels correlated with disease activity, as assessed by DAS28-CRP. In addition, Ikaros, Helios and Aiolos were significantly downregulated in Th1 cells from RA patients, while no difference between healthy individuals and RA was observed in Th17 cells. In summary, Helios and Aiolos expression in Treg cells correlates with disease activity and the expression levels of Ikaros transcription factors are diminished in Treg cells from RA patients. This observation could explain the reduced stability of Treg cells in RA.

T Cell Extracellular Traps: Tipping the Balance Between Skin Health and Disease

The role of extracellular traps (ETs) in the innate immune response against pathogens is well established. ETs were first identified in neutrophils and have since been identified in several other immune cells. Although the mechanistic details are not yet fully understood, recent reports have described antigen-specific T cells producing T cell extracellular traps (TETs). Depending on their location within the cutaneous environment, TETs may be beneficial to the host by their ability to limit the spread of pathogens and provide protection against damage to body tissues, and promote early wound healing and degradation of inflammatory mediators, leading to the resolution of inflammatory responses within the skin. However, ETs have also been associated with worse disease outcomes. Here, we consider host-microbe ET interactions by highlighting how cutaneous T cell-derived ETs aid in orchestrating host immune responses against Cutibacterium acnes (C. acnes), a commensal skin bacterium that contributes to skin health, but is also associated with acne vulgaris and surgical infections following joint-replacement procedures. Insights on the role of the skin microbes in regulating T cell ET formation have broad implications not only in novel probiotic design for acne treatment, but also in the treatment for other chronic inflammatory skin disorders and autoimmune diseases.

Favorable vaccine-induced SARS-CoV-2 specific T cell response profile in patients undergoing immune-modifying therapies

BACKGROUND

Patients undergoing immune-modifying therapies demonstrate a reduced humoral response after COVID-19 vaccination, but we lack a proper evaluation of the effect of such therapies on vaccine-induced T cell responses.

METHODS

We longitudinally characterized humoral and spike-specific T cell responses in patients with inflammatory bowel disease (IBD), who were on antimetabolite therapy (azathioprine or methotrexate), TNF inhibitors, and/or other biologic treatment (anti-integrin or anti-p40) for up to 6 months after completing 2-dose COVID-19 mRNA vaccination.

RESULTS

We demonstrate that a spike-specific T cell response was not only induced in treated patients with IBD at levels similar to those of healthy individuals, but also sustained at higher magnitude for up to 6 months after vaccination, particularly in those treated with TNF inhibitor therapy. Furthermore, the spike-specific T cell response in these patients was mainly preserved against mutations present in SARS-CoV-2 B.1.1.529 (Omicron) and characterized by a Th1/IL-10 cytokine profile.

CONCLUSION

Despite the humoral response defects, patients under immune-modifying therapies demonstrated a favorable profile of vaccine-induced T cell responses that might still provide a layer of COVID-19 protection.

FUNDING

This study was funded by the National Centre for Infectious Diseases (NCID) Catalyst Grant (FY2021ES) and the National Research Fund Competitive Research Programme (NRF-CRP25-2020-0003).

miR-155-overexpressing monocytes resemble HLAhighISG15+ synovial tissue macrophages from patients with rheumatoid arthritis and induce polyfunctional CD4+ T-cell activation

MicroRNAs (miRs) are known to regulate pro-inflammatory effector functions of myeloid cells, and miR dysregulation is implicated in rheumatoid arthritis (RA), a condition characterized by inflammation and destruction of the joints. We showed previously that miR-155 is increased in myeloid cells in RA and induces pro-inflammatory activation of monocytes and macrophages; however, its role at the interface between innate and adaptive immunity was not defined. Here, RNA-sequencing revealed that overexpression of miR-155 in healthy donor monocytes conferred a specific gene profile which bears similarities to that of RA synovial fluid-derived CD14+ cells and HLAhighISG15+ synovial tissue macrophages, both of which are characterized by antigen-presenting pathways. In line with this, monocytes in which miR-155 was overexpressed, displayed increased expression of HLA-DR and both co-stimulatory and co-inhibitory molecules, and induced activation of polyfunctional T cells. Together, these data underpin the notion that miR-155-driven myeloid cell activation in the synovium contributes not only to inflammation but may also influence the adaptive immune response.

Th17 cells in the liver: balancing autoimmunity and pathogen defense

In addition to carcinogenesis, T helper 17 (Th17) cells (a subtype of CD4 + T lymphocytes) are involved in the acute, chronic, and cirrhotic phases of liver diseases; however, their role in the development and progression of liver diseases remains unclear. It is difficult to elucidate the role of Th17 cells in liver diseases due to their dichotomous nature, i.e., plasticity in terms of pathogenic or host protective function depending on environmental and time phase factors. Moreover, insufficient depletion of Th17 cells by inhibiting the cytokines and transcription factors involved in their production causes difficulties in analyzing their specific role in vitro and in vivo murine models, partially due to complex interaction. This review summarizes the recent progress in understanding the plasticity and function of hepatic Th17 cells and type 3 cytokines.

Tumour necrosis factor inhibitors in inflammatory bowel disease: the story continues

In the 1990s, tumour necrosis factor-α inhibitor therapy ushered in the biologic therapy era for inflammatory bowel disease, leading to marked improvements in treatment options and patient outcomes. There are currently four tumour necrosis factor-α inhibitors approved as treatments for ulcerative colitis and/or Crohn's disease: infliximab, adalimumab, golimumab and certolizumab pegol. Despite the clear benefits of tumour necrosis factor-α inhibitors, a subset of patients with inflammatory bowel disease either do not respond, experience a loss of response after initial clinical improvement or report intolerance to anti-tumour necrosis factor-α therapy. Optimizing outcomes of these agents may be achieved through earlier intervention, the use of therapeutic drug monitoring and thoughtful switching within class. To complement these approaches, evolving predictive biomarkers may help inform and optimize clinical decision making by identifying patients who might potentially benefit from an alternative treatment strategy. This review will focus on the current use of tumour necrosis factor-α inhibitors in inflammatory bowel disease and the application of personalized medicine to improve future outcomes for all patients.

Therapeutic Effect of IL-38 on Experimental Autoimmune Uveitis: Reprogrammed Immune Cell Landscape and Reduced Th17 Cell Pathogenicity

Purpose

The purpose of this study was to elucidate the effects of interleukin (IL)-38 on experimental autoimmune uveitis (EAU) and its underlying mechanisms.

Methods

Mice with EAU were treated with IL-38, and the retinas and cervical draining lymph nodes (CDLNs) were analyzed by flow cytometry. Single-cell RNA sequencing (scRNA-seq) was conducted to analyze the immune cell profiles of CDLNs from normal, EAU, and IL-38-treated mice.

Results

Administration of IL-38 attenuated EAU symptoms and reduced the proportion of T helper 17 (Th17) and T helper 1 (Th1) cells in the retinas and CDLNs. In scRNA-seq analysis, IL-38 downregulated the IL-17 signaling pathway and reduced the expression of Th17 cell pathogenicity-related genes (Csf2 and Il23r), findings which were also confirmed by flow cytometry. In vitro, IL-38 reduced the granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulation function of IL-23 and inhibited IL-23R expression in Th17 cells. Moreover, when co-cultured with Th17 cells, IL-38 prevented IL-23 production in antigen-presenting cells (APCs).

Conclusions

Our data demonstrate the therapeutic effect of IL-38 on EAU, and suggest that the effect of IL-38 may be caused by dampening of the GM-CSF/IL-23R/IL-23 feedback loop between Th17 cells and APCs.

Tumor-Infiltrating Immune-Related Long Non-Coding RNAs Indicate Prognoses and Response to PD-1 Blockade in Head and Neck Squamous Cell Carcinoma

Long non-coding RNAs (lncRNAs) in immune cells play critical roles in tumor cell–immune cell interactions. This study aimed to characterize the landscape of tumor-infiltrating immune-related lncRNAs (Ti-lncRNAs) and reveal their correlations with prognoses and immunotherapy response in head and neck squamous cell carcinoma (HNSCC). We developed a computational model to identify Ti-lncRNAs in HNSCC and analyzed their associations with clinicopathological features, molecular alterations, and immunotherapy response. A signature of nine Ti-lncRNAs demonstrated an independent prognostic factor for both overall survival and disease-free survival among the cohorts from Fudan University Shanghai Cancer Center, The Cancer Genome Atlas, GSE41613, and GSE42743. The Ti-lncRNA signature scores in immune cells showed significant associations with TP53 mutation, CDKN2A mutation, and hypoxia. Inferior signature scores were enriched in patients with high levels of PDCD1 and CTLA4 and high expanded immune gene signature (IGS) scores, who displayed good response to PD-1 blockade in HNSCC. Consistently, superior clinical response emerged in melanoma patients with low signature scores undergoing anti-PD-1 therapy. Moreover, the Ti-lncRNA signature was a prognostic factor independent of PDCD1, CTLA4, and the expanded IGS score. In conclusion, tumor-infiltrating immune profiling identified a prognostic Ti-lncRNA signature indicative of clinical response to PD-1 blockade in HNSCC.

Role of Apoptotic Cell Clearance in Pneumonia and Inflammatory Lung Disease

Pneumonia and inflammatory diseases of the pulmonary system such as chronic obstructive pulmonary disease and asthma continue to cause significant morbidity and mortality globally. While the etiology of these diseases is highly different, they share a number of similarities in the underlying inflammatory processes driving disease pathology. Multiple recent studies have identified failures in efferocytosis-the phagocytic clearance of apoptotic cells-as a common driver of inflammation and tissue destruction in these diseases. Effective efferocytosis has been shown to be important for resolving inflammatory diseases of the lung and the subsequent restoration of normal lung function, while many pneumonia-causing pathogens manipulate the efferocytic system to enhance their growth and avoid immunity. Moreover, some treatments used to manage these patients, such as inhaled corticosteroids for chronic obstructive pulmonary disease and the prevalent use of statins for cardiovascular disease, have been found to beneficially alter efferocytic activity in these patients. In this review, we provide an overview of the efferocytic process and its role in the pathophysiology and resolution of pneumonia and other inflammatory diseases of the lungs, and discuss the utility of existing and emerging therapies for modulating efferocytosis as potential treatments for these diseases.

Established and emergent roles for Ikaros transcription factors in lymphoid cell development and function

Ikaros zinc finger transcription factors are important regulators of the gene programs underlying the development of hematopoietic cell lineages. The family consists of five members: Ikaros, Helios, Aiolos, Eos, and Pegasus, which engage in both homo- and heterotypic intrafamilial interactions to exert diverse functional effects. Pioneering studies focused on the role of these factors in early lymphoid development, as their absence resulted in severe defects in lymphocyte populations. More recent work has now begun to define nuanced, stage-specific roles for Ikaros family members in the differentiation and function of mature T, B, and innate lymphoid cell populations including natural killer (NK) cells. The precise transcriptional mechanisms by which these factors function, both independently and collaboratively, is an area of active investigation. However, several key themes appear to be emerging regarding the pathways influenced by Ikaros family members, including the end-to-end regulation of cytokine signaling. Here, we review roles for Ikaros factors in lymphoid cell development, differentiation, and function, including a discussion of the current understanding of the transcriptional mechanisms they employ and considerations for the future study of this important transcription factor family.

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.

Distinct Roles of LFA-1 and ICAM-1 on ILC2s Control Lung Infiltration, Effector Functions, and Development of Airway Hyperreactivity

Asthma is a heterogeneous airway inflammatory disease characterized by increased airway hyperreactivity (AHR) to specific and unspecific stimuli. Group 2 innate lymphoid cells (ILC2)s are type-2 cytokine secreting cells capable of inducing eosinophilic lung inflammation and AHR independent of adaptive immunity. Remarkably, reports show that ILC2s are increased in the blood of human asthmatics as compared to healthy donors. Nevertheless, whether ILC2 expression of adhesion molecules regulates ILC2 trafficking remains unknown. Our results show that IL-33-activated ILC2s not only express LFA-1 but also strikingly LFA-1 ligand ICAM-1. Both LFA-1^-/- and ICAM-1^-/- mice developed attenuated AHR in response to IL-33 intranasal challenge, associated with a lower airway inflammation and less lung ILC2 accumulation compared to controls. Our mixed bone marrow chimera studies however revealed that ILC2 expression of LFA-1 - but not ICAM-1 - was required for their accumulation in the inflamed lungs. Importantly, we found that LFA-1 remarkably controlled ILC2 homing to the lungs, suggesting that LFA-1 is involved in ILC2 trafficking to the lungs. Our exploratory transcriptomic analysis further revealed that ICAM-1 deficiency on ILC2s significantly affects their effector functions. While it downregulated pro-inflammatory cytokines such as Il5, Il9, Il13, and Csf2, it however notably also upregulated cytokines including Il10 both at the transcriptomic and protein levels. These findings provide novel avenues for future investigations, as modulation of LFA-1 and/or ICAM-1 represents an unappreciated regulatory mechanism for ILC2 trafficking and cytokine production respectively, potentially serving as therapeutic target for ILC2-dependent diseases such as allergic asthma.

Interleukin-17 in rheumatoid arthritis: Trials and tribulations

Interleukin-17A (IL-17A) is a pro-inflammatory cytokine with well-characterized biological effects on stromal cell activation, angiogenesis, and osteoclastogenesis. The presence of this cytokine in the inflamed joints of patients with rheumatoid arthritis (RA), together with compelling data from in vitro and experimental arthritis models demonstrating its pro-inflammatory effects, made this cytokine a strong candidate for therapeutic targeting. Clinical trials, however, have shown relatively modest success in RA as compared with other indications. Guided by recent insights in IL-17 biology, this review aims to explore possible reasons for the limited clinical efficacy of IL-17A blockade in RA, and what we can learn from these results going forward.

CCL26 regulates the proportion of CD4+CD25+FOXP3+ Tregs and the production of inflammatory factors in peripheral blood mononuclear cells following acute ischemic stroke via the STAT5 pathway

Acute ischemic stroke (AIS) is the most common type of stroke. Recent studies have found that AIS is closely involved in the immune regulation function of regulatory T cells (Tregs). C-C motif chemokine ligand 26 (CCL26) is a member of the chemokine family that plays an essential role in cell activation, cell differentiation, lymphocyte homing, and inflammatory and immune responses. The present study aimed to investigate the role of CCL26 in the regulation of Tregs in AIS. Peripheral blood mononuclear cells (PBMCs) were incubated with a CCL26-neutralizing antibody. The proportion of cluster of differentiation (CD)4⁺CD25⁺ forkhead box P3 (FOXP3)⁺ Tregs was increased, and the expression of FOXP3, phosphorylated signal transducer and activator of transcription 5 (p-STAT5), and that of the immunosuppressive factors, interleukin (IL)-10 and transforming growth factor (TGF)-β1, was upregulated. Conversely, the expression of immune-promoting factors, such as tumor necrosis factor (TNF)-α and IL-6 was significantly downregulated. Further experiments using CCL26 recombinant protein-treated PBMCs revealed a decreased proportion of CD4⁺CD25⁺FOXP3⁺ Tregs and the downregulated expression of FOXP3, p-STAT5, TGF-β1 and IL-10. Moreover, the expression of immunostimulatory factors, such as CX3C chemokine receptor 1, TNF-α and IL-6 was significantly upregulated. On the whole, these results demonstrate that CCL26 regulates the proportion of CD4⁺CD25⁺FOXP3⁺ Tregs and the production of inflammatory factors in PBMCs following AIS via the STAT5 pathway.

IKZF3/Aiolos Is Associated with but Not Sufficient for the Expression of IL-10 by CD4+ T Cells

The expression of anti-inflammatory IL-10 by CD4+ T cells is indispensable for immune homeostasis, as it allows T cells to moderate their effector function. We previously showed that TNF-α blockade during T cell stimulation in CD4+ T cell/monocyte cocultures resulted in maintenance of IL-10-producing T cells and identified IKZF3 as a putative regulator of IL-10. In this study, we tested the hypothesis that IKZF3 is a transcriptional regulator of IL-10 using a human CD4+ T cell-only culture system. IL-10+ CD4+ T cells expressed the highest levels of IKZF3 both ex vivo and after activation compared with IL-10-CD4+ T cells. Pharmacological targeting of IKZF3 with the drug lenalidomide showed that IKZF3 is required for anti-CD3/CD28 mAb-mediated induction of IL-10 but is dispensable for ex vivo IL-10 expression. However, overexpression of IKZF3 was unable to upregulate IL-10 at the mRNA or protein level in CD4+ T cells and did not drive the transcription of the IL10 promoter or putative local enhancer constructs. Collectively, these data indicate that IKZF3 is associated with but not sufficient for IL-10 expression in CD4+ T cells.

Effects of tumor necrosis factor on viral replication and pulmonary inflammation during acute mouse adenovirus type 1 respiratory infection

CD8 T cells contribute to effective clearance of mouse adenovirus type 1 (MAV-1) and to virus-induced pulmonary inflammation. We characterized effects of a CD8 T cell effector, TNF, on MAV-1 pathogenesis. TNF inhibited MAV-1 replication in vitro. TNF deficiency or immunoneutralization had no effect on lung viral loads or viral gene expression in mice infected intranasally with MAV-1. Absence of TNF delayed virus-induced weight loss and reduced histological evidence of pulmonary inflammation, although concentrations of proinflammatory cytokines and chemokines in bronchoalveolar lavage fluid (BALF) were not significantly affected. BALF concentrations of IL-10 were greater in TNF-deficient mice compared to controls. Our data indicate that TNF is not essential for control of viral replication in vivo, but virus-induced TNF contributes to some aspects of immunopathology and disease. Redundant CD8 T cell effectors and other aspects of immune function are sufficient for antiviral and pro-inflammatory responses to acute MAV-1 respiratory infection.

Synovial tissue transcriptomes of long-standing rheumatoid arthritis are dominated by activated macrophages that reflect microbial stimulation

Advances in microbiome research suggest involvement in chronic inflammatory diseases such as rheumatoid arthritis (RA). Searching for initial trigger(s) in RA, we compared transcriptome profiles of highly inflamed RA synovial tissue (RA-ST) and osteoarthritis (OA)-ST with 182 selected reference transcriptomes of defined cell types and their activation by exogenous (microbial) and endogenous inflammatory stimuli. Screening for dominant changes in RA-ST demonstrated activation of monocytes/macrophages with gene-patterns induced by bacterial and fungal triggers. Gene-patterns of activated B- or T-cells in RA-ST reflected a response to activated monocytes/macrophages rather than inducing their activation. In contrast, OA-ST was dominated by gene-patterns of non-activated macrophages and fibroblasts. The difference between RA and OA was more prominent in transcripts of secreted proteins and was confirmed by protein quantification in synovial fluid (SF) and serum. In total, 24 proteins of activated cells were confirmed in RA-SF compared to OA-SF and some like CXCL13, CCL18, S100A8/A9, sCD14, LBP reflected this increase even in RA serum. Consequently, pathogen-like response patterns in RA suggest that direct microbial influences exist. This challenges the current concept of autoimmunity and immunosuppressive treatment and advocates new diagnostic and therapeutic strategies that consider microbial persistence as important trigger(s) in the etiopathogenesis of RA.

Interplay between Cytokine Circuitry and Transcriptional Regulation Shaping Helper T Cell Pathogenicity and Plasticity in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic disorder manifested as Crohn’s disease (CD) and ulcerative colitis (UC) characterized by intestinal inflammation and involves a dysregulated immune response against commensal microbiota through the activation of CD4 T helper cells. T helper cell differentiation to effector or regulatory phenotypes is controlled by cytokine networks and transcriptional regulators. Distinct polarized T helper cells are able to alter their phenotypes to adapt to diverse and fluctuating physiological environments. T helper cells exhibit intrinsic instability and flexibility to express cytokines of other lineages or transdifferentiate from one T helper cell type to another in response to various perturbations from physiological cytokine milieu as a means of promoting local immunity in response to injury or ensure tissue homeostasis. Furthermore, functional plasticity and diversity of T helper cells are associated with pathogenicity and are critical for immune homeostasis and prevention of autoimmunity. In this review, we provide deeper insights into the combinatorial extrinsic and intrinsic signals that control plasticity and transdifferentiation of T helper cells and also highlight the potential of exploiting the genetic reprogramming plasticity of T helper cells in the treatment of IBD.

Coronavirus Disease 2019-related dyspnea cases difficult to interpret using chest computed tomography

Patients with Coronavirus Disease 2019 (COVID-19) often have clinical characteristics, such as chest tightness and dyspnea. Continuous, unresolved dyspnea often indicates the progression of lung lesions. The mechanism that underlies the chest distress and dyspnea in patients with COVID-19 is still unclear. Chest CT has a higher sensitivity and can play an essential role in the diagnosis and treatment of the disease. However, our clinical observations showed that although some patients had significant chest distress and dyspnea, the lesions that were observed in the lungs during computed tomography were milder and not completely consistent with clinical symptoms. We analyzed the clinical characteristics, laboratory test results, and imaging findings of these patients. We found that extensive inflammation of the bilateral and respiratory bronchioles in patients with COVID-19 due to excessive activation of proinflammatory cytokines and chemotactic aggregation of T-lymphocytes at the site of inflammation are possible mechanisms underlying chest distress and dyspnea in patients with COVID-19. Short-time and lose-dose use of corticosteroid may be helpful to treat chest tightness and dyspnea in mild COVID-19 patients. Through this study, we aimed to improve our understanding of the pathogenesis of COVID-19.

Update on the Pathomechanism, Diagnosis, and Treatment Options for Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease that involves multiple joints bilaterally. It is characterized by an inflammation of the tendon (tenosynovitis) resulting in both cartilage destruction and bone erosion. While until the 1990s RA frequently resulted in disability, inability to work, and increased mortality, newer treatment options have made RA a manageable disease. Here, great progress has been made in the development of disease-modifying anti-rheumatic drugs (DMARDs) which target inflammation and thereby prevent further joint damage. The available DMARDs are subdivided into (1) conventional synthetic DMARDs (methotrexate, hydrochloroquine, and sulfadiazine), (2) targeted synthetic DMARDs (pan-JAK- and JAK1/2-inhibitors), and (3) biologic DMARDs (tumor necrosis factor (TNF)-α inhibitors, TNF-receptor (R) inhibitors, IL-6 inhibitors, IL-6R inhibitors, B cell depleting antibodies, and inhibitors of co-stimulatory molecules). While DMARDs have repeatedly demonstrated the potential to greatly improve disease symptoms and prevent disease progression in RA patients, they are associated with considerable side-effects and high financial costs. This review summarizes our current understanding of the underlying pathomechanism, diagnosis of RA, as well as the mode of action, clinical benefits, and side-effects of the currently available DMARDs.

Tumor necrosis factor inhibition attenuates white matter gliosis after systemic inflammation in preterm fetal sheep

Background

Increased circulating levels of tumor necrosis factor (TNF) are associated with greater risk of impaired neurodevelopment after preterm birth. In this study, we tested the hypothesis that systemic TNF inhibition, using the soluble TNF receptor Etanercept, would attenuate neuroinflammation in preterm fetal sheep exposed to lipopolysaccharide (LPS).

Methods

Chronically instrumented preterm fetal sheep at 0.7 of gestation were randomly assigned to receive saline (control; n = 7), LPS infusion (100 ng/kg i.v. over 24 h then 250 ng/kg/24 h for 96 h plus 1 μg LPS boluses at 48, 72, and 96 h, to induce inflammation; n = 8) or LPS plus two i.v. infusions of Etanercept (2 doses, 5 mg/kg infused over 30 min, 48 h apart) started immediately before LPS-exposure (n = 8). Sheep were killed 10 days after starting infusions, for histology.

Results

LPS boluses were associated with increased circulating TNF, interleukin (IL)-6 and IL-10, electroencephalogram (EEG) suppression, hypotension, tachycardia, and increased carotid artery perfusion (P < 0.05 vs. control). In the periventricular and intragyral white matter, LPS exposure increased gliosis, TNF-positive cells, total oligodendrocytes, and cell proliferation (P < 0.05 vs control), but did not affect myelin expression or numbers of neurons in the cortex and subcortical regions. Etanercept delayed the rise in circulating IL-6, prolonged the increase in IL-10 (P < 0.05 vs. LPS), and attenuated EEG suppression, hypotension, and tachycardia after LPS boluses. Histologically, Etanercept normalized LPS-induced gliosis, and increase in TNF-positive cells, proliferation, and total oligodendrocytes.

Conclusion

TNF inhibition markedly attenuated white matter gliosis but did not affect mature oligodendrocytes after prolonged systemic inflammation in preterm fetal sheep. Further studies of long-term brain maturation are now needed.

Elevated T-helper 2 cytokine levels in high fat diet-fed C57BL/6 mice are attenuated by short-term 6-week treatment with a combination of low-dose aspirin and metformin

OBJECTIVE

To evaluate T-helper cytokine responses in a short-term high fat diet (HFD) induced impaired glucose metabolism. To further evaluate the modulation of T-helper 1 (Th₁) and T-helper 2 (Th₂) cytokines using short-term low-dose aspirin in combination with metformin.

DESIGN

Two experiments were carried out in this study in order to evaluate the T-helper cytokine profiles in a state of impaired glucose metabolism. A total of 28 six-week-old male C57BL/6 mice were used in this study. In the first experiment, mice were fed either a high fat diet or low fat diet for a duration of 10 weeks. We then determined the Th₁, Th₂ and T-helper 17 (Th₁₇) cytokine profiles. In the second experiment, we evaluated whether the short term 6-week treatment with low-dose aspirin in combination with metformin modulates T-helper cytokine profiles of the HFD-fed mice.

MEASUREMENTS

In the first experiment, we measured the body weights, blood glucose levels, insulin levels, lipid profiles and haematological parameters. We further performed oral glucose tolerance testing following an 8-hour fast and serum Th₁, Th₂ and Th₁₇ cytokine levels were also determined following short-term 8-week diet-feeding and 6-week low-dose aspirin and combined metformin with low-dose aspirin treatment.

RESULTS

High fat diet-feeding caused a marked increase in circulating peripheral blood lymphocytes, which was attenuated by short-term low-dose aspirin treatment. Moreover, the HFD feeding resulted in 2-fold increase in total cholesterol and a 4-fold increase in low-density lipoprotein cholesterol when compared to the low-fat diet-fed group (p < 0.05). In the high fat diet group, impaired glucose metabolism was associated with skewed Th₂ responses without alterations in the Th₁ and Th₁₇ cytokine profiles. Interestingly the short-term treatment with low-dose aspirin showed no effect on the selected T-helper 1 cytokine IFN-Ƴ (P > 0.05). While the combination of low-dose aspirin with metformin considerably reduced the levels of serum IFN-Ƴ (P < 0.05). Furthermore low-dose aspirin treatment showed the modest attenuation of the selected Th₂ cytokines, IL-10 and IL-13 when compared to low-dose aspirin with metformin (P < 0.01).

CONCLUSION

The early immunological and metabolic changes that occur in a state impaired glucose tolerance are accompanied by the increased production of Th₂ cell cytokines. The short-term treatment using low-dose aspirin combined with metformin may provide therapeutic benefits in preventing complications associated with dysregulated Th₂ cell responses.

Molecular switches for regulating the differentiation of inflammatory and IL-10-producing anti-inflammatory T-helper cells

CD4 T-helper (Th) cells secret a variety of inflammatory cytokines and play critical roles in host defense against invading foreign pathogens. On the other hand, uncontrolled inflammatory responses mediated by Th cells may result in tissue damage and inflammatory disorders including autoimmune and allergic diseases. Thus, the induction of anti-inflammatory cytokine expression becomes an important "brake" to repress and/or terminate aberrant and/or unnecessary immune responses. Interleukin-10 (IL-10) is one of the most important anti-inflammatory cytokines to limit inflammatory Th cells and immunopathology and to maintain tissue homeostasis. Many studies have indicated that Th cells can be a major source of IL-10 under specific conditions both in mouse and human and that extracellular signals and cell intrinsic molecular switches are required to turn on and off Il10 expression in different Th cells. In this review, we will highlight the recent findings that have enhanced our understanding on the mechanisms of IL-10 induction in distinct Th-cell subsets, including Th1, Th2, and Th17 cells, as well as the importance of these IL-10-producing anti-inflammatory Th cells in immunity and inflammation.

Involvement of TNF-Producing CD8+ Effector Memory T Cells with Immunopathogenesis of Erythema Nodosum Leprosum in Leprosy Patients

Type 2 reaction (T2R) or erythema nodosum leprosum (ENL), a sudden episode of acute inflammation predominantly affecting lepromatous leprosy patients (LL), characterized by a reduced cellular immune response. This possibly indicates a close relationship between the onset of T2R and the altered frequency, and functional activity of T lymphocytes, particularly of memory subsets. This study performed ex vivo and in vitro characterizations of T cell blood subpopulations from LL patients with or without T2R. In addition, the evaluation of activity of these subpopulations was performed by analyzing the frequency of these cells producing IFN-γ, TNF, and IL-10 by flow cytometry. Furthermore, the expression of transcription factors, for the differentiation of T cells, were analyzed by quantitative real-time polymerase chain reaction. Our results showed an increased frequency of CD8⁺/TNF⁺ effector memory T cells (T_EM) among T2Rs. Moreover, there was evidence of a reduced frequency of CD4 and CD8⁺ IFN-γ-producing cells in T2R, and a reduced expression of STAT4 and TBX21. Finally, a significant and positive correlation between bacteriological index (BI) of T2R patients and CD4⁺/TNF⁺ and CD4⁺/IFN-γ⁺ T cells was observed. Thus, negative correlation between BI and the frequency of CD4⁺/IL-10⁺ T cells was noted. These results suggest that CD8⁺/TNF⁺ T_EM are primarily responsible for the transient alteration in the immune response to Mycobacterium leprae in ENL patients. Thus, our study improves our understanding of pathogenic mechanisms and might suggest new therapeutic approaches for leprosy.

Anti-TNF treatment negatively regulates human CD4+ T-cell activation and maturation in vitro, but does not confer an anergic or suppressive phenotype

TNF‐blockade has shown clear therapeutic value in rheumatoid arthritis and other immune‐mediated inflammatory diseases, however its mechanism of action is not fully elucidated. We investigated the effects of TNF‐blockade on CD4⁺ T cell activation, maturation, and proliferation, and assessed whether TNF‐inhibitors confer regulatory potential to CD4⁺ T cells. CyTOF and flow cytometry analysis revealed that in vitro treatment of human CD4⁺ T cells with the anti‐TNF monoclonal antibody adalimumab promoted IL‐10 expression in CD4⁺ T cells, whilst decreasing cellular activation. In line with this, analysis of gene expression profiling datasets of anti‐TNF‐treated IL‐17 or IFN‐γ‐producing CD4⁺ T cells revealed changes in multiple pathways associated with cell cycle and proliferation. Kinetics experiments showed that anti‐TNF treatment led to delayed, rather than impaired T‐cell activation and maturation. Whilst anti‐TNF‐treated CD4⁺ T cells displayed some hyporesponsiveness upon restimulation, they did not acquire enhanced capacity to suppress T‐cell responses or modulate monocyte phenotype. These cells however displayed a reduced ability to induce IL‐6 and IL‐8 production by synovial fibroblasts. Together, these data indicate that anti‐TNF treatment delays human CD4⁺ T‐cell activation, maturation, and proliferation, and this reduced activation state may impair their ability to activate stromal cells.

Functions and regulation of T cell-derived interleukin-10

Interleukin (IL)-10 is an essential anti-inflammatory cytokine and functions as a negative regulator of immune responses to microbial antigens. IL-10 is particularly important in maintaining the intestinal microbe-immune homeostasis. Loss of IL-10 promotes the development of inflammatory bowel disease (IBD) as a consequence of an excessive immune response to the gut microbiota. IL-10 also functions more generally to prevent excessive inflammation during the course of infection. Although IL-10 can be produced by virtually all cells of the innate and adaptive immune system, T cells constitute a non-redundant source for IL-10 in many cases. The various roles of T cell-derived IL-10 will be discussed in this review. Given that IL-10 is at the center of maintaining the delicate balance between effective immunity and tissue protection, it is not surprising that IL-10 expression is highly dynamic and tightly regulated. We summarize the environmental signals and molecular pathways that regulate IL-10 expression. While numerous studies have provided us with a deep understanding of IL-10 biology, the majority of findings have been made in murine models, prompting us to highlight gaps in our knowledge about T cell-derived IL-10 in the human system.

Precision medicine in psoriatic arthritis: how should we select targeted therapies?

Psoriatic arthritis (PsA) is a heterogeneous inflammatory arthritis associated with psoriasis. Patients manifest variable presentations with potential involvement of peripheral joints, spine, tendons, skin, and nails. There has been a rapid expansion in targeted treatment options for patients with PsA, but typically less than half of those who receive therapy achieve optimal treatment targets. Many patients respond to second-line or third-line biological therapies, but little evidence exists to guide the choice of therapeutics for each individual. At present, choice of therapy is driven by active clinical disease domains, clinician familiarity with existing treatments, and cost. Here, we review recent data that highlight the potential for personalised, or precision, medicine in PsA and other forms of inflammatory arthritis, noting that this research is still at a preliminary stage. In the future, a combination of detailed immunophenotyping and sophisticated statistical analyses should help to facilitate a personalised medicine approach in PsA, following examples from other clinical areas, such as oncology. This change in approach to the treatment of PsA has the potential to maximise outcomes for patients and to provide optimal therapies without delay.

IL-17 in the immunopathogenesis of spondyloarthritis

Spondyloarthritis (SpA) is a term that refers to a group of inflammatory diseases that includes psoriatic arthritis, axial SpA and nonradiographic axial SpA, reactive arthritis, enteropathic arthritis and undifferentiated SpA. The disease subtypes share clinical and immunological features, including joint inflammation (peripheral and axial skeleton); skin, gut and eye manifestations; and the absence of diagnostic autoantibodies (seronegative). The diseases also share genetic factors. The aetiology of SpA is still the subject of research by many groups worldwide. Evidence from genetic, experimental and clinical studies has accumulated to indicate a clear role for the IL-17 pathway in the pathogenesis of SpA. The IL-17 family consists of IL-17A, IL-17B, IL-17C, IL-17D, IL-17E and IL-17F, of which IL-17A is the best studied. IL-17A is a pro-inflammatory cytokine that also has the capacity to promote angiogenesis and osteoclastogenesis. Of the six family members, IL-17A has the strongest homology with IL-17F. In this Review, we discuss how IL-17A and IL-17F and their cellular sources might contribute to the immunopathology of SpA.

Tumor Necrosis Factor-Alpha Antagonist Interferes With the Formation of Granulomatous Multinucleated Giant Cells: New Insights Into Mycobacterium tuberculosis Infection

More than half of tuberculosis cases in the world are due to resuscitation of dormant Mycobacterium tuberculosis (Mtb) sequestered into cell-derived structures called granulomas. It is fairly admitted that cytokines and more particularly Tumor Necrosis Factor (TNF)-α is critical in the control of Mtb infections and that anti-TNF-α drugs constitute one of the main risk factors for reactivation of latent Mtb infection. The aim of this study was to evaluate the role of etanercept, a dimeric fusion protein consisting of the extracellular ligand-binding portion of the human p75 TNF receptor linked to the Fc portion of human IgG1, in an in vitro model of human tuberculous granuloma. We showed that etanercept slightly delayed the formation of granuloma and reduced the generation of multinuclear giant cells (MGCs). In addition, etanercept exacerbated the expression of M1 polarization genes but also induced interleukin (IL)-10 release. In addition, our results indicated that etanercept inhibited cell fusion in an IL-10-dependent manner. Moreover, adalimumab, a human monoclonal anti-TNF-α IgG1 inhibited MGC formation in granuloma, without altering IL-10 secretion and induced macrophage apoptosis. Taken together, our data provides new insights into the role of TNF-α blockers in MGCs formation and the impact of such immunomodulatory drugs on tuberculous granuloma maturation.

Evaluation of Th1 and Th2 immune response in clinical and sub-clinical scrub typhus infection

Scrub typhus (ST), caused by a gram negative intracellular bacteria- Orientia tsutsugamushi, is one among the leading causes of febrile illness across Southeast Asia, including India. Clinical presentation can vary from asymptomatic to severely fatal. Th1-cell mediated immunity has been suggested to play an important role against ST infection in animal models. However, human data on protective immunity are limited. The present study was undertaken to identify host immune correlates that could confer protection in individuals that remain clinically asymptomatic/sub-clinical. Serum cytokine profiling and mRNA expression levels of Th1 (TNF-α, IFN-γ, IL-2) and Th2 (IL-10, IL-6, IL-4) cytokines was studied amongst the clinical and sub-clinical infections. It was observed that a Th1/Th2 pattern is not involved in human ST infection irrespective of being a symptomatic or asymptomatic presentation. However, significant difference was observed in IL-10 serum and gene expression levels. This study suggests a possible role of IL-10 in disease phenotypic presentation. Over-production of IL-10 was found to be a significant factor contributing to the severity of the disease whereas a protective immune mechanism might exist with a low level of IL-10 in ST infection.

Anti-TNF Therapy in Spondyloarthritis and Related Diseases, Impact on the Immune System and Prediction of Treatment Responses

Immune-mediated inflammatory diseases (IMIDs), such as spondyloarthritis (SpA), psoriasis, Crohn's disease (CD), and rheumatoid arthritis (RA) remain challenging illnesses. They often strike at a young age and cause lifelong morbidity, representing a considerable burden for the affected individuals and society. Pioneering studies have revealed the presence of a TNF-dependent proinflammatory cytokine cascade in several IMIDs, and the introduction of anti-TNF therapy 20 years ago has proven effective to reduce inflammation and clinical symptoms in RA, SpA, and other IMID, providing unprecedented clinical benefits and a valid alternative in case of failure or intolerable adverse effects of conventional disease-modifying antirheumatic drugs (DMARDs, for RA) or non-steroidal anti-inflammatory drugs (NSAIDs, for SpA). However, our understanding of how TNF inhibitors (TNFi) affect the immune system in patients is limited. This question is relevant because anti-TNF therapy has been associated with infectious complications. Furthermore, clinical efficacy of TNFi is limited by a high rate of non-responsiveness (30–40%) in RA, SpA, and other IMID, exposing a substantial fraction of patients to side-effects without clinical benefit. Despite the extensive use of TNFi, it is still not possible to determine which patients will respond to TNFi before treatment initiation. The recent introduction of antibodies blocking IL-17 has expanded the therapeutic options for SpA, as well as psoriasis and psoriatic arthritis. It is therefore essential to develop tools to guide treatment decisions for patients affected by SpA and other IMID, both to optimize clinical care and contain health care costs. After a brief overview of the biology of TNF, its receptors and currently used TNFi in the clinics, we summarize the progress that has been made to increase our understanding of the action of TNFi on the immune system in patients. We then summarize efforts dedicated to identify biomarkers that can predict treatment responses to TNFi and we conclude with a section dedicated to the recently introduced inhibitors of IL-17A and IL-23 in SpA and related diseases. The focus of this review is on SpA, however, we also refer to RA on topics for which only limited information is available on SpA in the literature.

Effector Functions of CD4+ T Cells at the Site of Local Autoimmune Inflammation-Lessons From Rheumatoid Arthritis

Infiltration of memory CD4+ T cells in synovial joints of Rheumatoid Arthritis (RA) patients has been reported since decades. Moreover, several genome wide association studies (GWAS) pinpointing a key genetic association between the HLA-DR locus and RA have led to the generally agreed hypothesis that CD4+ T cells are directly implicated in the disease. Still, RA is a heterogeneous disease and much effort has been made to understand its different facets. T cell differentiation is driven by mechanisms including antigen stimulation, co-stimulatory signals and cytokine milieu, all of which are abundant in the rheumatic joint, implying that any T cells migrating into the joint may be further affected locally. In parallel to the characterization and classification of T-cell subsets, the contribution of different effector T cells to RA has been investigated in numerous studies though sometimes with contradictory results. In particular, the frequency of Th1 and Th17 cells has been assessed in the synovial joints with various results that could, at least partly, be explained by the stage of the disease. For regulatory T cells, it is largely accepted that they accumulate in RA synovial fluid and that the equilibrium between regulatory T cells and effector cells is a key factor in controlling inflammation processes involved in RA. Recent phenotypic studies describe the possible implication of a novel subset of peripheral T helper cells (Tph) important for T-B cell cross talk and plasma cell differentiation in the RA joint of ACPA+ (autoantibodies against citrullinated proteins) RA patients. Finally, cytotoxic CD4+ T cells, historically described as increased in the peripheral blood of RA patients have attracted new attention in the last years. In view of the recently identified peripheral T-cell subsets, we will integrate immunological data as well as information on genetic variants and therapeutic strategy outcomes into our current understanding of the width of effector T cells. We will also integrate tissue-resident memory T cell aspects, and discuss similarities and differences with inflammatory conditions in skin (psoriasis) and mucosal organs (Crohn's disease).

The cholesterol biosynthesis pathway regulates IL-10 expression in human Th1 cells

The mechanisms controlling CD4+ T cell switching from an effector to an anti-inflammatory (IL-10+) phenotype play an important role in the persistence of chronic inflammatory diseases. Here, we identify the cholesterol biosynthesis pathway as a key regulator of this process. Pathway analysis of cultured cytokine-producing human T cells reveals a significant association between IL-10 and cholesterol metabolism gene expression. Inhibition of the cholesterol biosynthesis pathway with atorvastatin or 25-hydroxycholesterol during switching from IFNγ+ to IL-10+ shows a specific block in immune resolution, defined as a significant decrease in IL-10 expression. Mechanistically, the master transcriptional regulator of IL10 in T cells, c-Maf, is significantly decreased by physiological levels of 25-hydroxycholesterol. Strikingly, progression to rheumatoid arthritis is associated with altered expression of cholesterol biosynthesis genes in synovial biopsies of predisposed individuals. Our data reveal a link between sterol metabolism and the regulation of the anti-inflammatory response in human CD4+ T cells.

Transplantation of mesenchymal stem cells genetically engineered to overexpress interleukin-10 promotes alternative inflammatory response in rat model of traumatic brain injury

Background

Traumatic brain injury (TBI) is a major cause for long-term disability, yet the treatments available that improve outcomes after TBI limited. Neuroinflammatory responses are key contributors to determining patient outcomes after TBI. Transplantation of mesenchymal stem cells (MSCs), which release trophic and pro-repair cytokines, represents an effective strategy to reduce inflammation after TBI. One such pro-repair cytokine is interleukin-10 (IL-10), which reduces pro-inflammatory markers and trigger alternative inflammatory markers, such as CD163. In this study, we tested the therapeutic effects of MSCs that were engineered to overexpress IL-10 when transplanted into rats following TBI in the medial frontal cortex.

Methods

Thirty-six hours following TBI, rats were transplanted with MSCs and then assessed for 3 weeks on a battery of behavioral tests that measured motor and cognitive abilities. Histological evaluation was then done to measure the activation of the inflammatory response. Additionally, immunomodulatory effects were evaluated by immunohistochemistry and Western blot analyses.

Results

A significant improvement in fine motor function was observed in rats that received transplants of MSCs engineered to overexpress IL-10 (MSCs + IL-10) or MSCs alone compared to TBI + vehicle-treated rats. Although tissue spared was unchanged, anti-inflammatory effects were revealed by a reduction in the number of glial fibrillary acidic protein cells and CD86 cells in both TBI + MSCs + IL-10 and TBI + MSC groups compared to TBI + vehicle rats. Microglial activation was significantly increased in the TBI + MSC group when compared to the sham + vehicle group. Western blot data suggested a reduction in tumor necrosis factor-alpha in the TBI + MSCs + IL-10 group compared to TBI + MSC group. Immunomodulatory effects were demonstrated by a shift from classical inflammation expression (CD86) to an alternative inflammation state (CD163) in both treatments with MSCs and MSCs + IL-10. Furthermore, co-labeling of both CD86 and CD163 was detected in the same cells, suggesting a temporal change in macrophage expression.

Conclusions

Overall, our findings suggest that transplantation of MSCs that were engineered to overexpress IL-10 can improve functional outcomes by providing a beneficial perilesion environment. This improvement may be explained by the shifting of macrophage expression to a more pro-repair state, thereby providing a possible new therapy for treating TBI.