Insulin-Like Growth Factors Are Key Regulators of T Helper 17 Regulatory T Cell Balance in Autoimmunity

Review of Codonopsis Radix biological activities: A plant of traditional Chinese tonic

ETHNOPHARMACOLOGICAL RELEVANCE

Codonopsis Radix, commonly known as Dangshen in Chinese, is frequently used to treat deficiencies of spleen and lung Qi, gastrointestinal discomfort, fatigue, asthmatic breathing, sallow complexion, lack of strength, shortness of breath, deficiencies of both Qi and blood, as well as impairments to both Qi and body fluids in suboptimal health status.

AIM OF THE REVIEW

This review systematically expounds on the modern pharmacological studies related to the use of Codonopsis Radix in invigorating Qi and nourishing the body in recent years. The aim is to provide theoretical research and reference for the in-depth and systematic exploration and development of the applications of Codonopsis Radix in the fields of food and medicine.

MATERIALS AND METHODS

This study employs "Codonopsis Radix," "Codonopsis," and "Dangshen" as keywords to gather pertinent information on Codonopsis Radix medicine through electronic searches of classical literature and databases such as PubMed, Elsevier, Google Scholar, Wiley, EMBASE, Cochrane Library, Web of Science, CNKI, Wanfang, VIP, and Baidu Scholar.

RESULTS

From previous studies, activities such as immune system modulation, gastrointestinal motility regulation, cardiac function revitalization, lung function improvement, blood circulation enhancement, aging process deceleration, learning and memory augmentation, fatigue resistance enhancement, and liver and kidney damage protection of Codonopsis Radix have been reported. Recognized as an important medicine and food homologous traditional Chinese herbal remedy for supplementing deficiencies, its mode of action is multi-elemental, multi-systemic, multi-organ, multi-mechanistic, and multi-targeted. Furthermore, the benefits of its tonic surpass its therapeutic value, establishing it as an extraordinary preventive and therapeutic medicine.

CONCLUSIONS

With its long history of traditional applications and the revelations of contemporary pharmacological research, Codonopsis Radix exhibits great potential as both a therapeutic agent and a dietary supplement for further research in medicine, nutrition, and healthcare.

An open-label, randomized controlled trial to assess a ketogenic diet in critically ill patients with sepsis

Patients with sepsis experience metabolic and immunologic dysfunction that may be amplified by standard carbohydrate-based nutrition. A ketogenic diet (KD) may offer an immunologically advantageous alternative, although clinical evidence is limited. We conducted a single-center, open-label, randomized controlled trial to assess whether a KD could induce stable ketosis in critically ill patients with sepsis. Secondary outcomes included assessment of feasibility and safety of KD, as well as explorative analysis of clinical and immunological characteristics. Forty critically ill adults were randomized to either a ketogenic or standard high-carbohydrate diet. Stable ketosis was achieved in all KD patients, with significant increases in β-hydroxybutyrate levels compared with controls [mean difference 1.4 milimoles per liter; 95% confidence interval (CI): 1.0 to 1.8; P < 0.001). No major adverse events or harmful metabolic side effects (acidosis, dysglycemia, or dyslipidemia) were observed. After day 4, none of the patients in the KD group required insulin treatment, whereas in the control group, insulin dependency ranged between 35% and 60% (P = 0.009). There were no differences in 30-day survival, but ventilation-free [incidence rate ratio (IRR) 1.7; 95% CI: 1.5 to 2.1; P < 0.001], vasopressor-free (IRR 1.7; 95% CI: 1.5 to 2.0; P < 0.001), dialysis-free (IRR 1.5; 95% CI: 1.3 to 1.8; P < 0.001), and intensive care unit-free days (IRR 1.7; 95% CI: 1.4 to 2.1; P < 0.001) were higher in the ketogenic group. Next-generation sequencing of CD4+/CD8+ T cells and protein analyses showed reduced immune dysregulation, with decreased gene expression of T-cell activation and signaling markers and lower pro-inflammatory cytokine secretion. This trial demonstrated the safe induction of a stable ketogenic state in sepsis, warranting larger trials to investigate potential benefits in sepsis-related organ dysfunction.

SLAM/SAP signaling regulates discrete γδ T cell developmental checkpoints and shapes the innate-like γδ TCR repertoire

During thymic development, most γδ T cells acquire innate-like characteristics that are critical for their function in tumor surveillance, infectious disease, and tissue repair. The mechanisms, however, that regulate γδ T cell developmental programming remain unclear. Recently, we demonstrated that the SLAM-SAP signaling pathway regulates the development and function of multiple innate-like γδ T cell subsets. Here, we used a single-cell proteogenomics approach to identify SAP-dependent developmental checkpoints and to define the SAP-dependent γδ TCR repertoire. SAP deficiency resulted in both a significant loss of an immature Gzma + Blk + Etv5 + Tox2 + γδT17 precursor population, and a significant increase in Cd4 + Cd8+ Rorc + Ptcra + Rag1 + thymic γδ T cells. SAP-dependent diversion of embryonic day 17 thymic γδ T cell clonotypes into the αβ T cell developmental pathway was associated with a decreased frequency of mature clonotypes in neonatal thymus, and an altered γδ TCR repertoire in the periphery. Finally, we identify TRGV4/TRAV13-4(DV7)-expressing T cells as a novel, SAP-dependent Vγ4 γδT1 subset. Together, the data suggest that SAP-dependent γδ/αβ T cell lineage commitment regulates γδ T cell developmental programming and shapes the γδ TCR repertoire.

Genome-wide DNA methylation profiles and breast cancer among World Trade Center survivors

Background

Increased incidence of cancer has been reported among World Trade Center (WTC)-exposed persons. Aberrant DNA methylation is a hallmark of cancer development. To date, only a few small studies have investigated the relationship between WTC exposure and DNA methylation. The main objective of this study was to assess the DNA methylation profiles of WTC-exposed community members who remained cancer free and those who developed breast cancer.

Methods

WTC-exposed women were selected from the WTC Environmental Health Center clinic, with peripheral blood collected during routine clinical monitoring visits. The reference group was selected from the NYU Women's Health Study, a prospective cohort study with blood samples collected before 9 November 2001. The Infinium MethylationEPIC array was used for global DNA methylation profiling, with adjustments for cell type composition and other confounders. Annotated probes were used for biological pathway and network analysis.

Results

A total of 64 WTC-exposed (32 cancer free and 32 with breast cancer) and 32 WTC-unexposed (16 cancer free and 16 with prediagnostic breast cancer) participants were included. Hypermethylated cytosine-phosphate-guanine probe sites (defined as β > 0.8) were more common among WTC-exposed versus unexposed participants (14.3% vs. 4.5%, respectively, among the top 5000 cytosine-phosphate-guanine sites). Cancer-related pathways (e.g., human papillomavirus infection, cGMP-PKG) were overrepresented in WTC-exposed groups (breast cancer patients and cancer-free subjects). Compared to the unexposed breast cancer patients, 47 epigenetically dysregulated genes were identified among WTC-exposed breast cancers. These genes formed a network, including Wnt/β-catenin signaling genes WNT4 and TCF7L2, and dysregulation of these genes contributes to cancer immune evasion.

Conclusion

WTC exposure likely impacts DNA methylation and may predispose exposed individuals toward cancer development, possibly through an immune-mediated mechanism.

ECHDC2 inhibits the proliferation of gastric cancer cells by binding with NEDD4 to degrade MCCC2 and reduce aerobic glycolysis

BACKGROUND

The Enoyl-CoA hydratase/isomerase family plays a crucial role in the metabolism of tumors, being crucial for maintaining the energy balance and biosynthetic needs of cancer cells. However, the enzymes within this family that are pivotal in gastric cancer (GC) remain unclear.

METHODS

We employed bioinformatics techniques to identify key Enoyl-CoA hydratase/isomerase in GC. The expression of ECHDC2 and its clinical significance were validated through tissue microarray analysis. The role of ECHDC2 in GC was further assessed using colony formation assays, CCK8 assay, EDU assay, Glucose and lactic acid assay, and subcutaneous tumor experiments in nude mice. The mechanism of action of ECHDC2 was validated through Western blotting, Co-immunoprecipitation, and immunofluorescence experiments.

RESULTS

Our analysis of multiple datasets indicates that low expression of ECHDC2 in GC is significantly associated with poor prognosis. Overexpression of ECHDC2 notably inhibits aerobic glycolysis and proliferation of GC cells both in vivo and in vitro. Further experiments revealed that overexpression of ECHDC2 suppresses the P38 MAPK pathway by inhibiting the protein level of MCCC2, thereby restraining glycolysis and proliferation in GC cells. Ultimately, it was discovered that ECHDC2 promotes the ubiquitination and subsequent degradation of MCCC2 protein by binding with NEDD4.

CONCLUSIONS

These findings underscore the pivotal role of the ECHDC2 in regulating aerobic glycolysis and proliferation in GC cells, suggesting ECHDC2 as a potential therapeutic target in GC.

IL-21 conditions antigen-presenting human γδ T-cells to promote IL-10 expression in naïve and memory CD4+ T-cells

Direct interaction between T-cells exerts a major influence on tissue immunity and inflammation across multiple body sites including the human gut, which is highly enriched in 'unconventional' lymphocytes such as γδ T-cells. We previously reported that microbial activation of human Vγ9/Vδ2+ γδ T-cells in the presence of the mucosal damage-associated cytokine IL-15 confers the ability to promote epithelial barrier defence, specifically via induction of IL-22 expression in conventional CD4+ T-cells. In the current report, we assessed whether other cytokines enriched in the gut milieu also functionally influence microbe-responsive Vγ9/Vδ2 T-cells. When cultured in the presence of IL-21, Vγ9/Vδ2 T-cells acquired the ability to induce expression of the immunoregulatory cytokine IL-10 in both naïve and memory CD4+ T-cells, at levels surpassing those induced by monocytes or monocyte-derived DCs. These findings identify an unexpected influence of IL-21 on Vγ9/Vδ2 T-cell modulation of CD4+ T-cell responses. Further analyses suggested a possible role for CD30L and/or CD40L reverse signalling in mediating IL-10 induction by IL-21 conditioned Vγ9/Vδ2 T-cells. Our findings indicate that the local microenvironment exerts a profound influence on Vγ9/Vδ2 T-cell responses to microbial challenge, leading to induction of distinct functional profiles among CD4+ T-cells that may influence inflammatory events at mucosal surfaces. Targeting these novel pathways may offer therapeutic benefit in disorders such as inflammatory bowel disease.

Cellular senescence in cancer: molecular mechanisms and therapeutic targets

Aging exhibits several hallmarks in common with cancer, such as cellular senescence, dysbiosis, inflammation, genomic instability, and epigenetic changes. In recent decades, research into the role of cellular senescence on tumor progression has received widespread attention. While how senescence limits the course of cancer is well established, senescence has also been found to promote certain malignant phenotypes. The tumor-promoting effect of senescence is mainly elicited by a senescence-associated secretory phenotype, which facilitates the interaction of senescent tumor cells with their surroundings. Targeting senescent cells therefore offers a promising technique for cancer therapy. Drugs that pharmacologically restore the normal function of senescent cells or eliminate them would assist in reestablishing homeostasis of cell signaling. Here, we describe cell senescence, its occurrence, phenotype, and impact on tumor biology. A "one-two-punch" therapeutic strategy in which cancer cell senescence is first induced, followed by the use of senotherapeutics for eliminating the senescent cells is introduced. The advances in the application of senotherapeutics for targeting senescent cells to assist cancer treatment are outlined, with an emphasis on drug categories, and the strategies for their screening, design, and efficient targeting. This work will foster a thorough comprehension and encourage additional research within this field.

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

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

Single-cell RNA sequencing reveals Immune Education promotes T cell survival in mice subjected to the cecal ligation and puncture sepsis model

Background

Individual T cell responses vary significantly based on the microenvironment present at the time of immune response and on prior induced T cell memory. While the cecal ligation and puncture (CLP) model is the most commonly used murine sepsis model, the contribution of diverse T cell responses has not been explored. We defined T cell subset responses to CLP using single-cell RNA sequencing and examined the effects of prior induced T cell memory (Immune Education) on these responses. We hypothesized that Immune Education prior to CLP would alter T cell responses at the single cell level at a single, early post-CLP time point.

Methods

Splenic T cells were isolated from C57BL/6 mice. Four cohorts were studied: Control, Immune-Educated, CLP, and Immune-Educated CLP. At age 8 weeks, Immune-Educated and Immune-Educated CLP mice received anti-CD3ϵ antibody; Control and CLP mice were administered an isotype control. CLP (two punctures with a 22-gauge needle) was performed at 12-13 weeks of life. Mice were sacrificed at baseline or 24-hours post-CLP. Unsupervised clustering of the transcriptome library identified six distinct T cell subsets: quiescent naïve CD4+, primed naïve CD4+, memory CD4+, naïve CD8+, activated CD8+, and CD8+ cytotoxic T cell subsets. T cell subset specific gene set enrichment analysis and Hurdle analysis for differentially expressed genes (DEGs) were performed.

Results

T cell responses to CLP were not uniform - subsets of activated and suppressed T cells were identified. Immune Education augmented specific T cell subsets and led to genomic signatures favoring T cell survival in unoperated and CLP mice. Additionally, the combination of Immune Education and CLP effected the expression of genes related to T cell activity in ways that differed from CLP alone. Validating our finding that IL7R pathway markers were upregulated in Immune-Educated CLP mice, we found that Immune Education increased T cell surface IL7R expression in post-CLP mice.

Conclusion

Immune Education enhanced the expression of genes associated with T cell survival in unoperated and CLP mice. Induction of memory T cell compartments via Immune Education combined with CLP may increase the model's concordance to human sepsis.

Th17/Treg balance: the bloom and wane in the pathophysiology of sepsis

Sepsis is a multi-organ dysfunction characterized by an unregulated host response to infection. It is associated with high morbidity, rapid disease progression, and high mortality. Current therapies mainly focus on symptomatic treatment, such as blood volume supplementation and antibiotic use, but their effectiveness is limited. Th17/Treg balance, based on its inflammatory property, plays a crucial role in determining the direction of the inflammatory response and the regression of organ damage in sepsis patients. This review provides a summary of the changes in T-helper (Th) 17 cell and regulatory T (Treg) cell differentiation and function during sepsis, the heterogeneity of Th17/Treg balance in the inflammatory response, and the relationship between Th17/Treg balance and organ damage. Th17/Treg balance exerts significant control over the bloom and wanes in host inflammatory response throughout sepsis.

Keratinocyte-derived circulating microRNAs in extracellular vesicles: a novel biomarker of psoriasis severity and potential therapeutic target

BACKGROUND

Psoriasis is a chronic inflammatory disorder characterized by pathogenic hyperproliferation of keratinocytes and immune dysregulation. Currently, objective evaluation tools reflecting the severity of psoriasis are insufficient. MicroRNAs in extracellular vesicles (EV miRNAs) have been shown to be potential biomarkers for various inflammatory diseases. Our objective was to investigate the possibility of plasma-derived EV miRNAs as a marker for the psoriasis disease severity.

METHODS

EVs were extracted from the plasma of 63 patients with psoriasis and 12 with Behçet's disease. We performed next-generation sequencing of the plasma-derived EV miRNAs from the psoriasis patients. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to validate the level of EV miRNA expression. In situ hybridization was used to discern the anatomical location of miRNAs. qRT-PCR, western blotting, and cell counting kits (CCKs) were used to investigate IGF-1 signaling in cells transfected with miRNA mimics.

RESULTS

We identified 19 differentially expressed EV miRNAs and validated the top three up-and down-regulated EV miRNAs. Among these, miR-625-3p was significantly increased in patients with severe psoriasis in both plasma and skin and most accurately distinguished moderate-to-severe psoriasis from mild-to-moderate psoriasis. It was produced and secreted by keratinocytes upon stimulation. We also observed a significant intensification of IGF-1 signalling and increased cell numbers in the miR-625-3p mimic transfected cells.

CONCLUSIONS

We propose keratinocyte-derived EV miR-625-3p as a novel and reliable biomarker for estimating the severity of psoriasis. This biomarker could objectively evaluate the severity of psoriasis in the clinical setting and might serve as a potential therapeutic target. Trial registration None.

Emerging mechanisms of obesity-associated immune dysfunction

Obesity is associated with a wide range of complications, including type 2 diabetes mellitus, cardiovascular disease, hypertension and nonalcoholic fatty liver disease. Obesity also increases the incidence and progression of cancers, autoimmunity and infections, as well as lowering vaccine responsiveness. A unifying concept across these differing diseases is dysregulated immunity, particularly inflammation, in response to metabolic overload. Herein, we review emerging mechanisms by which obesity drives inflammation and autoimmunity, as well as impairing tumour immunosurveillance and the response to infections. Among these mechanisms are obesity-associated changes in the hormones that regulate immune cell metabolism and function and drive inflammation. The cargo of extracellular vesicles derived from adipose tissue, which controls cytokine secretion from immune cells, is also dysregulated in obesity, in addition to impairments in fatty acid metabolism related to inflammation. Furthermore, an imbalance exists in obesity in the biosynthesis and levels of polyunsaturated fatty acid-derived oxylipins, which control a range of outcomes related to inflammation, such as immune cell chemotaxis and cytokine production. Finally, there is a need to investigate how obesity influences immunity using innovative model systems that account for the heterogeneous nature of obesity in the human population.

Patients with ankylosing spondylitis present a distinct CD8 T cell subset with osteogenic and cytotoxic potential

OBJECTIVES

Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease affecting mainly the axial skeleton. Peripheral involvement (arthritis, enthesitis and dactylitis) and extra-musculoskeletal manifestations, including uveitis, psoriasis and bowel inflammation, occur in a relevant proportion of patients. AS is responsible for chronic and severe back pain caused by local inflammation that can lead to osteoproliferation and ultimately spinal fusion. The association of AS with the human leucocyte antigen-B27 gene, together with elevated levels of chemokines, CCL17 and CCL22, in the sera of patients with AS, led us to study the role of CCR4+ T cells in the disease pathogenesis.

METHODS

CD8+CCR4+ T cells isolated from the blood of patients with AS (n=76) or healthy donors were analysed by multiparameter flow cytometry, and gene expression was evaluated by RNA sequencing. Patients with AS were stratified according to the therapeutic regimen and current disease score.

RESULTS

CD8+CCR4+ T cells display a distinct effector phenotype and upregulate the inflammatory chemokine receptors CCR1, CCR5, CX3CR1 and L-selectin CD62L, indicating an altered migration ability. CD8+CCR4+ T cells expressing CX3CR1 present an enhanced cytotoxic profile, expressing both perforin and granzyme B. RNA-sequencing pathway analysis revealed that CD8+CCR4+ T cells from patients with active disease significantly upregulate genes promoting osteogenesis, a core process in AS pathogenesis.

CONCLUSIONS

Our results shed light on a new molecular mechanism by which T cells may selectively migrate to inflammatory loci, promote new bone formation and contribute to the pathological ossification process observed in AS.

Insulin and IGF-1 have both overlapping and distinct effects on CD4+ T cell mitochondria, metabolism, and function

Insulin and insulin-like growth factor 1 (IGF-1) are metabolic hormones with known effects on CD4+ T cells through insulin receptor (IR) and IGF-1 receptor (IGF-1R) signaling. Here, we describe specific and distinct roles for these hormones and receptors. We have found that IGF-1R, but not IR, expression is increased following CD4+ T cell activation or following differentiation toward Th17 cells. Although both insulin and IGF-1 increase the metabolism of CD4+ T cells, insulin has a more potent effect. However, IGF-1 has a unique role and acts specifically on Th17 cells to increase IL-17 production and Th17 cell metabolism. Furthermore, IGF-1 decreases mitochondrial membrane potential and mitochondrial reactive oxygen species (mROS) in Th17 cells, providing a cytoprotective effect. Interestingly, both IR and IGF-1R are required for this effect of IGF-1 on mitochondria, which suggests that the hybrid IR/IGF-1R may be required for mediating the effect of IGF-1 on mitochondrial membrane potential and mROS production.

Manipulating the tumor immune microenvironment to improve cancer immunotherapy: IGF1R, a promising target

Cancer immunotherapy has made impressive advances in improving the outcome of patients affected by malignant diseases. Nonetheless, some limitations still need to be tackled to more efficiently and safely treat patients, in particular for those affected by solid tumors. One of the limitations is related to the immunosuppressive tumor microenvironment (TME), which impairs anti-tumor immunity. Efforts to identify targets able to turn the TME into a milieu more auspicious to current immuno-oncotherapy is a real challenge due to the high redundancy of the mechanisms involved. However, the insulin-like growth factor 1 receptor (IGF1R), an attractive drug target for cancer therapy, is emerging as an important immunomodulator and regulator of key immune cell functions. Here, after briefly summarizing the IGF1R signaling pathway in cancer, we review its role in regulating immune cells function and activity, and discuss IGF1R as a promising target to improve anti-cancer immunotherapy.

Feline Comorbidities: Hypersomatotropism-induced diabetes in cats

PRACTICAL RELEVANCE

Diabetes mellitus is the second-most common feline endocrinopathy, affecting an estimated 1/200 cats. While the underlying causes vary, around 15-25% of cats with diabetes mellitus develop the condition secondarily to progressive growth hormone (GH)-induced insulin resistance. This typically results in a form of diabetes that is challenging to manage, whereby the response to insulin is very variable or high doses are required to achieve even minimal diabetic control.

CLINICAL CHALLENGES

Although uncontrolled chronic excessive GH may result in phenotypic changes that raise suspicion for acromegaly, many cats with hypersomatotropism (HST) do not have these changes. In these situations, a clinician's index of suspicion may be increased by the presence of less dramatic changes such as marked polyphagia, stertor or uncontrolled diabetes mellitus. The current diagnostic test of choice is demonstration of a markedly increased serum insulin-like growth factor 1 (IGF1) concentration, but some affected cats will have only a marginal increase; additionally, chronic insulin administration in cats results in an increase in serum IGF1, making the diagnosis less clear cut and requiring additional confirmatory tests.

EVIDENCE BASE

Over the past two decades, HST has increasingly been recognised as an underlying cause of diabetes mellitus in cats. This review, which focuses on diagnosis and treatment, utilises data from observational studies, clinical trials and case series, as well as drawing on the experience of the authors in managing this condition.

Mechanistic target of rapamycin in regulating macrophage function in inflammatory cardiovascular diseases

The mechanistic target of rapamycin (mTOR) is evolutionarily conserved from yeast to humans and is one of the most fundamental pathways of living organisms. Since its discovery three decades ago, mTOR has been recognized as the center of nutrient sensing and growth, homeostasis, metabolism, life span, and aging. The role of dysregulated mTOR in common diseases, especially cancer, has been extensively studied and reported. Emerging evidence supports that mTOR critically regulates innate immune responses that govern the pathogenesis of various cardiovascular diseases. This review discusses the regulatory role of mTOR in macrophage functions in acute inflammation triggered by ischemia and in atherosclerotic cardiovascular disease (ASCVD) and heart failure with preserved ejection fraction (HFpEF), in which chronic inflammation plays critical roles. Specifically, we discuss the role of mTOR in trained immunity, immune senescence, and clonal hematopoiesis. In addition, this review includes a discussion on the architecture of mTOR, the function of its regulatory complexes, and the dual-arm signals required for mTOR activation to reflect the current knowledge state. We emphasize future research directions necessary to understand better the powerful pathway to take advantage of the mTOR inhibitors for innovative applications in patients with cardiovascular diseases associated with aging and inflammation.

Systemic immunometabolism and responses to vaccines: insights from T and B cell perspectives

Vaccination stands as the cornerstone in the battle against infectious diseases, and its efficacy hinges on several host-related factors like genetics, age, and metabolic status. Vulnerable populations, such as malnourished individuals, the obese, and the elderly, commonly exhibit diminished vaccine responses and efficacy. While the specific factors contributing to this impairment may vary, these individuals typically display a degree of metabolic dysregulation, thereby underscoring its potential significance as a fundamental determinant of suboptimal vaccine responses. The emerging field of immunometabolism aims to unravel the intricate interplay between immune regulation and metabolic pathways, and recent research has revealed diverse metabolic signatures linked to various vaccine responses and outcomes. In this review, we summarize the major metabolic pathways utilized by B and T cells during vaccine responses, their complex and varied metabolic requirements, and the impact of micronutrients and metabolic hormones on vaccine outcomes. Furthermore, we examine how systemic metabolism influences vaccine responses and the evidence suggesting that metabolic dysregulation in vulnerable populations can lead to impaired vaccine responses. Lastly, we reflect on the challenge of proving causality with respect to the contribution of metabolic dysregulation to poor vaccine outcomes, and highlight the need for a systems biology approach that combines multimodal profiling and mathematical modelling to reveal the underlying mechanisms of such complex interactions.

CD4+ T cells are homeostatic regulators during Mtb reinfection

Immunological priming - either in the context of prior infection or vaccination - elicits protective responses against subsequent Mycobacterium tuberculosis (Mtb) infection. However, the changes that occur in the lung cellular milieu post-primary Mtb infection and their contributions to protection upon reinfection remain poorly understood. Here, using clinical and microbiological endpoints in a non-human primate reinfection model, we demonstrate that prior Mtb infection elicits a long-lasting protective response against subsequent Mtb exposure and that the depletion of CD4+ T cells prior to Mtb rechallenge significantly abrogates this protection. Leveraging microbiologic, PET-CT, flow cytometric, and single-cell RNA-seq data from primary infection, reinfection, and reinfection-CD4+ T cell depleted granulomas, we identify differential cellular and microbial features of control. The data collectively demonstrate that the presence of CD4+ T cells in the setting of reinfection results in a reduced inflammatory lung milieu characterized by reprogrammed CD8+ T cell activity, reduced neutrophilia, and blunted type-1 immune signaling among myeloid cells, mitigating Mtb disease severity. These results open avenues for developing vaccines and therapeutics that not only target CD4+ and CD8+ T cells, but also modulate innate immune cells to limit Mtb disease.

Age-associated Senescent - T Cell Signaling Promotes Type 3 Immunity that Inhibits the Biomaterial Regenerative Response

Aging is associated with immunological changes that compromise response to infections and vaccines, exacerbate inflammatory diseases and can potentially mitigate tissue repair. Even so, age-related changes to the immune response to tissue damage and regenerative medicine therapies remain unknown. Here, it is characterized how aging induces changes in immunological signatures that inhibit tissue repair and therapeutic response to a clinical regenerative biological scaffold derived from extracellular matrix. Signatures of inflammation and interleukin (IL)-17 signaling increased with injury and treatment both locally and regionally in aged animals, and computational analysis uncovered age-associated senescent-T cell communication that promotes type 3 immunity in T cells. Local inhibition of type 3 immune activation using IL17-neutralizing antibodies improves healing and restores therapeutic response to the regenerative biomaterial, promoting muscle repair in older animals. These results provide insights into tissue immune dysregulation that occurs with aging that can be targeted to rejuvenate repair.

CD70-induced differentiation of proinflammatory Th1/17/22/GM lymphocytes associated with disease progression and immune reconstitution during HIV infection

Immune overactivation is a hallmark of chronic HIV infection, which is critical to HIV pathogenesis and disease progression. The imbalance of helper T cell (Th) differentiation and subsequent cytokine dysregulation are generally considered to be the major drivers of excessive activation and inflammatory disorders in HIV infection. However, the accurate factors driving HIV-associated Th changes remained to be established. CD70, which was a costimulatory molecule, was found to increase on CD4+ T cells during HIV infection. Overexpression of CD70 on CD4+ T cells was recently reported to associate with highly pathogenic proinflammatory Th1/Th17 polarization in multiple sclerosis. Thus, the role of CD70 in the imbalance of Th polarization and immune overactivation during HIV infection needs to be investigated. Here, we found that the elevated frequency of CD70 + CD4+ T cells was negatively correlated with CD4 count and positively associated with immune activation in treatment-naïve people living with HIV (PLWH). More importantly, CD70 expression defined a population of proinflammatory Th1/17/22/GM subsets in PLWH. Blocking CD70 decreased the mRNA expression of subset-specific markers during Th1/17/22/GM polarization. Furthermore, we demonstrated that CD70 influenced the differentiation of these Th cells through STAT pathway. Finally, it was revealed that patients with a high baseline level of CD70 on CD4+ T cells exhibited a greater risk of poor immune reconstitution after antiretroviral therapy (ART) than those with low CD70. In general, our data highlighted the role of CD70 in Th1/17/22/GM differentiation during HIV infection and provided evidence for CD70 as a potential biomarker for predicting immune recovery.

Allo Beta Cell transplantation: specific features, unanswered questions, and immunological challenge

Type 1 diabetes (T1D) presents a persistent medical challenge, demanding innovative strategies for sustained glycemic control and enhanced patient well-being. Beta cells are specialized cells in the pancreas that produce insulin, a hormone that regulates blood sugar levels. When beta cells are damaged or destroyed, insulin production decreases, which leads to T1D. Allo Beta Cell Transplantation has emerged as a promising therapeutic avenue, with the goal of reinstating glucose regulation and insulin production in T1D patients. However, the path to success in this approach is fraught with complex immunological hurdles that demand rigorous exploration and resolution for enduring therapeutic efficacy. This exploration focuses on the distinct immunological characteristics inherent to Allo Beta Cell Transplantation. An understanding of these unique challenges is pivotal for the development of effective therapeutic interventions. The critical role of glucose regulation and insulin in immune activation is emphasized, with an emphasis on the intricate interplay between beta cells and immune cells. The transplantation site, particularly the liver, is examined in depth, highlighting its relevance in the context of complex immunological issues. Scrutiny extends to recipient and donor matching, including the utilization of multiple islet donors, while also considering the potential risk of autoimmune recurrence. Moreover, unanswered questions and persistent gaps in knowledge within the field are identified. These include the absence of robust evidence supporting immunosuppression treatments, the need for reliable methods to assess rejection and treatment protocols, the lack of validated biomarkers for monitoring beta cell loss, and the imperative need for improved beta cell imaging techniques. In addition, attention is drawn to emerging directions and transformative strategies in the field. This encompasses alternative immunosuppressive regimens and calcineurin-free immunoprotocols, as well as a reevaluation of induction therapy and recipient preconditioning methods. Innovative approaches targeting autoimmune recurrence, such as CAR Tregs and TCR Tregs, are explored, along with the potential of stem stealth cells, tissue engineering, and encapsulation to overcome the risk of graft rejection. In summary, this review provides a comprehensive overview of the inherent immunological obstacles associated with Allo Beta Cell Transplantation. It offers valuable insights into emerging strategies and directions that hold great promise for advancing the field and ultimately improving outcomes for individuals living with diabetes.

Insulin signaling in development

Nutrient intake is obligatory for animal growth and development, but nutrients alone are not sufficient. Indeed, insulin and homologous hormones are required for normal growth even in the presence of nutrients. These hormones communicate nutrient status between organs, allowing animals to coordinate growth and metabolism with nutrient supply. Insulin and related hormones, such as insulin-like growth factors and insulin-like peptides, play important roles in development and metabolism, with defects in insulin production and signaling leading to hyperglycemia and diabetes. Here, we describe the insulin hormone family and the signal transduction pathways activated by these hormones. We highlight the roles of insulin signaling in coordinating maternal and fetal metabolism and growth during pregnancy, and we describe how secretion of insulin is regulated at different life stages. Additionally, we discuss the roles of insulin signaling in cell growth, stem cell proliferation and cell differentiation. We provide examples of the role of insulin in development across multiple model organisms: Caenorhabditis elegans, Drosophila, zebrafish, mouse and human.

Insulin-like Growth Factor-1 Synergizes with IL-2 to Induce Homeostatic Proliferation of Regulatory T Cells

IL-2 has been proposed to restore tolerance via regulatory T cell (Treg) expansion in autoimmunity, yet off-target effects necessitate identification of a combinatorial approach allowing for lower IL-2 dosing. We recently reported reduced levels of immunoregulatory insulin-like growth factor-1 (IGF1) during type 1 diabetes progression. Thus, we hypothesized that IGF1 would synergize with IL-2 to expand Tregs. We observed IGF1 receptor was elevated on murine memory and human naive Treg subsets. IL-2 and IGF1 promoted PI3K/Akt signaling in Tregs, inducing thymically-derived Treg expansion beyond either agent alone in NOD mice. Increased populations of murine Tregs of naive or memory, as well as CD5lo polyclonal or CD5hi likely self-reactive, status were also observed. Expansion was attributed to increased IL-2Rγ subunit expression on murine Tregs exposed to IL-2 and IGF1 as compared with IL-2 or IGF1 alone. Assessing translational capacity, incubation of naive human CD4+ T cells with IL-2 and IGF1 enhanced thymically-derived Treg proliferation in vitro, without the need for TCR ligation. We then demonstrated that IGF1 and IL-2 or IL-7, which is also IL-2Rγ-chain dependent, can be used to induce proliferation of genetically engineered naive human Tregs or T conventional cells, respectively. These data support the potential use of IGF1 in combination with common γ-chain cytokines to drive homeostatic T cell expansion, both in vitro and in vivo, for cellular therapeutics and ex vivo gene editing.

Blocking insulin-like growth factor 1 receptor signaling pathway inhibits neuromuscular junction regeneration after botulinum toxin-A treatment

Botulinum toxin-A (BTX) administration into muscle is an established treatment for conditions with excessive muscle contraction. However, botulinum therapy has short-term effectiveness, and high-dose injection of BTX could induce neutralizing antibodies against BTX. Therefore, prolonging its effects could be beneficial in a clinical situation. Insulin-like growth factor-1 receptor (IGF1R) and its ligands, insulin-like growth factor (IGF) -I and II, regulate the physiological and pathological processes of the nervous system. It has been suggested that IGF1R is involved in the process after BTX administration, but the specific regeneration mechanism remains unclear. Therefore, this study aimed to determine how inhibition of IGF1R signaling pathway affects BTX-induced muscle paralysis. The results showed that anti-IGF1R antibody administration inhibited the recovery from BTX-induced neurogenic paralysis, and the synaptic components at the neuromuscular junction (NMJ), mainly post-synaptic components, were significantly affected by the antibody. In addition, the wet weight or frequency distribution of the cross-sectional area of the muscle fibers was regulated by IGF1R, and sequential antibody administration following BTX treatment increased the number of Pax7+-satellite cells in the gastrocnemius (GC) muscle, independent of NMJ recovery. Moreover, BTX treatment upregulated mammalian target of rapamycin (mTOR)/S6 kinase signaling pathway, HDAC4, Myog, Fbxo32/MAFbx/Atrogin-1 pathway, and transcription of synaptic components, but not autophagy. Finally, IGF1R inhibition affected only mTOR/S6 kinase translational signaling in the GC muscle. In conclusion, the IGF1R signaling pathway is critical for NMJ regeneration via specific translational signals. IGF1R inhibition could be highly beneficial in clinical practice by decreasing the number of injections and total dose of BTX due to the prolonged duration of the effect.

Soya saponins and prebiotics alter intestinal functions in Ballan wrasse (Labrus bergylta)

A 5-week feeding trial was conducted in the cleaner fish Ballan wrasse (Labrus bergylta) for a better understanding of the basic biology of the intestinal functions and health in this stomach less species. During the trial, Ballan wrasse was fed either a reference diet, the reference diet supplemented with (i) a commercial prebiotic (Aquate™ SG, 0·4 %) expected to have beneficial effects, (ii) soya saponins (0·7 %) expected to induce inflammation or (iii) a combination of the prebiotics and the soya saponins to find a remedy for gut inflammation. Blood, intestinal tissue and gut content from four consecutive intestinal segments (IN1 - IN4) were collected. No significant differences in fish growth were observed between the four dietary groups. Saponin supplementation, both alone and in combination with prebiotics, increased weight index of IN2 and IN3 and decreased blood plasma glucose, cholesterol and total protein. Dry matter of intestinal content and activity of digestive enzymes were not affected by diet. Histomorphological analyses revealed a progressing inflammation with increased infiltration by immune cells particularly into the distal parts of the intestine in fish fed diets with saponins, both alone and in combination with prebiotics. Gene expression profiles obtained by RNA sequencing and quantitative PCR mirrored the histological and biochemical changes induced by the saponin load. The study demonstrated that Ballan wrasse gut health and digestive function may be markedly affected by feed ingredients containing antinutrients.

Immune aging - A mechanism in autoimmune disease

Evidence is emerging that the process of immune aging is a mechanism leading to autoimmunity. Over lifetime, the immune system adapts to profound changes in hematopoiesis and lymphogenesis, and progressively restructures in face of an ever-expanding exposome. Older adults fail to generate adequate immune responses against microbial infections and tumors, but accumulate aged T cells, B cells and myeloid cells. Age-associated B cells are highly efficient in autoantibody production. T-cell aging promotes the accrual of end-differentiated effector T cells with potent cytotoxic and pro-inflammatory abilities and myeloid cell aging supports a low grade, sterile and chronic inflammatory state (inflammaging). In pre-disposed individuals, immune aging can lead to frank autoimmune disease, manifesting with chronic inflammation and irreversible tissue damage. Emerging data support the concept that autoimmunity results from aging-induced failure of fundamental cellular processes in immune effector cells: genomic instability, loss of mitochondrial fitness, failing proteostasis, dwindling lysosomal degradation and inefficient autophagy. Here, we have reviewed the evidence that malfunctional mitochondria, disabled lysosomes and stressed endoplasmic reticula induce pathogenic T cells and macrophages that drive two autoimmune diseases, rheumatoid arthritis (RA) and giant cell arteritis (GCA). Recognizing immune aging as a risk factor for autoimmunity will open new avenues of immunomodulatory therapy, including the repair of malfunctioning mitochondria and lysosomes.

Linsitinib, an IGF-1R inhibitor, attenuates disease development and progression in a model of thyroid eye disease

Introduction

Graves' disease (GD) is an autoimmune disorder caused by autoantibodies against the thyroid stimulating hormone receptor (TSHR) leading to overstimulation of the thyroid gland. Thyroid eye disease (TED) is the most common extra thyroidal manifestation of GD. Therapeutic options to treat TED are very limited and novel treatments need to be developed. In the present study we investigated the effect of linsitinib, a dual small-molecule kinase inhibitor of the insulin-like growth factor 1 receptor (IGF-1R) and the Insulin receptor (IR) on the disease outcome of GD and TED.

Methods

Linsitinib was administered orally for four weeks with therapy initiating in either the early ("active") or the late ("chronic") phases of the disease. In the thyroid and the orbit, autoimmune hyperthyroidism and orbitopathy were analyzed serologically (total anti-TSHR binding antibodies, stimulating anti TSHR antibodies, total T4 levels), immunohistochemically (H&E-, CD3-, TNFa- and Sirius red staining) and with immunofluorescence (F4/80 staining). An MRI was performed to quantify in vivo tissue remodeling inside the orbit.

Results

Linsitinib prevented autoimmune hyperthyroidism in the early state of the disease, by reducing morphological changes indicative for hyperthyroidism and blocking T-cell infiltration, visualized by CD3 staining. In the late state of the disease linsitinib had its main effect in the orbit. Linsitinib reduced immune infiltration of T-cells (CD3 staining) and macrophages (F4/80 and TNFa staining) in the orbita in experimental GD suggesting an additional, direct effect of linsitinib on the autoimmune response. In addition, treatment with linsitinib normalized the amount of brown adipose tissue in both the early and late group. An in vivo MRI of the late group was performed and revealed a marked decrease of inflammation, visualized by ¹⁹F MR imaging, significant reduction of existing muscle edema and formation of brown adipose tissue.

Conclusion

Here, we demonstrate that linsitinib effectively prevents development and progression of thyroid eye disease in an experimental murine model for Graves' disease. Linsitinib improved the total disease outcome, indicating the clinical significance of the findings and providing a path to therapeutic intervention of Graves' Disease. Our data support the use of linsitinib as a novel treatment for thyroid eye disease.

Growth hormone releasing hormone signaling promotes Th17 cell differentiation and autoimmune inflammation

Dysregulation of Th17 cell differentiation and pathogenicity contributes to multiple autoimmune and inflammatory diseases. Previously growth hormone releasing hormone receptor (GHRH-R) deficient mice have been reported to be less susceptible to the induction of experimental autoimmune encephalomyelitis. Here, we show GHRH-R is an important regulator of Th17 cell differentiation in Th17 cell-mediated ocular and neural inflammation. We find that GHRH-R is not expressed in naïve CD4⁺ T cells, while its expression is induced throughout Th17 cell differentiation in vitro. Mechanistically, GHRH-R activates the JAK-STAT3 pathway, increases the phosphorylation of STAT3, enhances both non-pathogenic and pathogenic Th17 cell differentiation and promotes the gene expression signatures of pathogenic Th17 cells. Enhancing this signaling by GHRH agonist promotes, while inhibiting this signaling by GHRH antagonist or GHRH-R deficiency reduces, Th17 cell differentiation in vitro and Th17 cell-mediated ocular and neural inflammation in vivo. Thus, GHRH-R signaling functions as a critical factor that regulates Th17 cell differentiation and Th17 cell-mediated autoimmune ocular and neural inflammation.

Roles and regulation of microglia activity in multiple sclerosis: insights from animal models

As resident macrophages of the CNS, microglia are critical immune effectors of inflammatory lesions and associated neural dysfunctions. In multiple sclerosis (MS) and its animal models, chronic microglial inflammatory activity damages myelin and disrupts axonal and synaptic activity. In contrast to these detrimental effects, the potent phagocytic and tissue-remodelling capabilities of microglia support critical endogenous repair mechanisms. Although these opposing capabilities have long been appreciated, a precise understanding of their underlying molecular effectors is only beginning to emerge. Here, we review recent advances in our understanding of the roles of microglia in animal models of MS and demyelinating lesions and the mechanisms that underlie their damaging and repairing activities. We also discuss how the structured organization and regulation of the genome enables complex transcriptional heterogeneity within the microglial cell population at demyelinating lesions.

The potential role of T-cell metabolism-related molecules in chronic neuropathic pain after nerve injury: a narrative review

Neuropathic pain is a common type of chronic pain, primarily caused by peripheral nerve injury. Different T-cell subtypes play various roles in neuropathic pain caused by peripheral nerve damage. Peripheral nerve damage can lead to co-infiltration of neurons and other inflammatory cells, thereby altering the cellular microenvironment and affecting cellular metabolism. By elaborating on the above, we first relate chronic pain to T-cell energy metabolism. Then we summarize the molecules that have affected T-cell energy metabolism in the past five years and divide them into two categories. The first category could play a role in neuropathic pain, and we explain their roles in T-cell function and chronic pain, respectively. The second category has not yet been involved in neuropathic pain, and we focus on how they affect T-cell function by influencing T-cell metabolism. By discussing the above content, this review provides a reference for studying the direct relationship between chronic pain and T-cell metabolism and searching for potential therapeutic targets for the treatment of chronic pain on the level of T-cell energy metabolism.

T cell aging as a risk factor for autoimmunity

Immune aging is a complex process rendering the host susceptible to cancer, infection, and insufficient tissue repair. Many autoimmune diseases preferentially occur during the second half of life, counterintuitive to the concept of excess adaptive immunity driving immune-mediated tissue damage. T cells are particularly susceptible to aging-imposed changes, as they are under extreme proliferative pressure to fulfill the demands of clonal expansion and of homeostatic T cell repopulation. T cells in older adults have a footprint of genetic and epigenetic changes, lack mitochondrial fitness, and fail to maintain proteostasis, diverging them from host protection to host injury. Here, we review recent progress in understanding how the human T-cell system ages and the evidence detailing how T cell aging contributes to autoimmune conditions. T cell aging is now recognized as a risk determinant in two prototypic autoimmune syndromes; rheumatoid arthritis and giant cell arteritis. The emerging concept adds susceptibility to autoimmune and autoinflammatory disease to the spectrum of aging-imposed adaptations and opens new opportunities for immunomodulatory therapy by restoring the functional intactness of aging T cells.

Mitochondrial fusion induced by transforming growth factor-β1 serves as a switch that governs the metabolic reprogramming during differentiation of regulatory T cells

Although metabolic reprogramming during the differentiation of regulatory T cells (Treg cells) has been extensively studied, the molecular switch to alter energy metabolism remains undefined. The present study explores the critical role of mitochondrial dynamics in the reprogramming and consequent generation of Treg cells. The results showed that during Treg cell differentiation, mitochondrial fusion but not fission led to elevation of oxygen consumption rate values, facilitation of metabolic reprogramming, and increase of number of Treg cells and expression of Foxp3 in vitro and in vivo. Mechanistically, mitochondrial fusion favored fatty acid oxidation but restricted glycolysis in Treg cells through down-regulating the expression of HIF-1α. Transforming growth factor-β1 (TGF-β1) played a crucial role in the induction of mitochondrial fusion, which activated Smad2/3, promoted the expression of PGC-1α and therefore facilitated the expression of mitochondrial fusion proteins. In conclusion, during Treg cell differentiation, TGF-β1 promotes PGC-1α-mediated mitochondrial fusion, which drives metabolic reprogramming from glycolysis to fatty acid oxidation via suppressing HIF-1α expression, and therefore favors the generation of Treg cells. The signals and proteins involved in mitochondrial fusion are potential therapeutic targets for Treg cell-related diseases.

The relationship between CD4+ T cell glycolysis and their functions

CD4⁺ T cells are effector T cells (Teffs) produced by the differentiation of initial T cells in peripheral lymphoid tissue after being attacked by antigens, and have an indispensable role in the development and activation of B cells and CD8⁺ T cells to regulate and assist immunity. In this review, we provide a new perspective on the relationship between CD4⁺ T cell glycolysis and its function. We summarize the effects of changes in the glycolysis level of CD4⁺ T cells on their activation, differentiation, proliferation, and survival. In addition, we emphasize that regulation of the glycolysis level of CD4⁺ T cells changes their inflammatory phenotypes and function. The study of immune metabolism has received more attention recently, but more work is needed to answer many open questions.

FOXP3+ macrophage represses acute ischemic stroke-induced neural inflammation

Proper termination of cell-death-induced neural inflammation is the premise of tissue repair in acute ischemic stroke (AIS). Macrophages scavenge cell corpses/debris and produce inflammatory mediators that orchestrate immune responses. Here, we report that FOXP3, the key immune-repressive transcription factor of Tregs, is conditionally expressed in macrophages in stroke lesion. FOXP3 ablation in macrophages results in detrimental stroke outcomes, emphasizing the beneficial role of FOXP3+ macrophages. FOXP3+ macrophages are distinct from the M1 or M2 subsets and display superactive efferocytic capacity. With scRNAseq and analysis of FOXP3-bound-DNA isolated with CUT & RUN, we show that FOXP3 facilitates macrophage phagocytosis through enhancing cargo metabolism. FOXP3 expression is controlled by macroautophagic/autophagic protein degradation in resting macrophages, while initiation of LC3-associated phagocytosis (LAP) competitively occupies the autophagic machineries, and thus permits FOXP3 activation. Our data demonstrate a distinct set of FOXP3+ macrophages with enhanced scavenging capability, which could be a target in immunomodulatory therapy against AIS.Abbreviations: ADGRE1/F4/80: adhesion G protein-coupled receptor E1; AIF1/Iba1: allograft inflammatory factor 1; AIS: acute ischemic stroke; ARG1: arginase 1; ATP: adenosine triphosphate; BECN1/Beclin1: Beclin 1, autophagy related; BMDM: bone marrow-derived macrophages; CKO: conditional knockout; CSF1/M-CSF: colony stimulating factor 1 (macrophage); CSF2/GM-CSF: colony stimulating factor 2; CSF3/G-CSF: colony stimulating factor 3; CUT & RUN: cleavage under targets and release using nuclease; CyD: cytochalasin D; DAMP: danger/damage-associated molecular pattern; DIL: dioctadecyl-3,3,3,3-tetramethylin docarbocyanine; ELISA: enzyme linked immunosorbent assay; GO: Gene Ontology; FCGR3/CD16: Fc receptor, IgG, low affinity III; HMGB1: high mobility group box 1; IFNG/IFNγ: interferon gamma; IP: immunoprecipitation; KEGG: Kyoto Encyclopedia of Genes and Genomes; ITGAM/CD11b: integrin subunit alpha M; ITGAX/CD11c: integrin subunit alpha X; LAP: LC3-associated phagocytosis; LC-MS: liquid chromatography-mass spectrometry; LPS: lipopolysaccharide; MRC1/CD206: mannose receptor, C type 1; O4: oligodendrocyte marker O4; PBMC: peripheral blood mononuclear cells; RBC: red blood cells; PTPRC/CD45: protein tyrosine phosphatase, receptor type, C; RBFOX3/NeuN: RNA binding protein, fox 1 homolog (C. elegans) 3; RUBCN/Rubicon: RUN domain and cysteine-rich domain containing, Beclin 1-interacting protein; scRNAseq: single cell RNA sequencing; SQSTM1/p62 (sequestosome 1); TGFB/TGFβ: transforming growth factor, beta; tMCAO: transient middle cerebral artery occlusion; TNF/TNFα: tumor necrosis factor; Treg: regulatory T cell.

In silico repurposing of CNS drugs for multiple sclerosis

Multiple sclerosis (MS) is an autoimmune neurodegenerative disease affecting numerous people worldwide. While the relapsing subtypes of MS are to some extent treatable, the disease remains incurable leading to progressive disability. Limited efficacy of current small molecule drugs necessitates development of efficient and safe MS medications. Accordingly, drug repurposing is an invaluable strategy that recognizes new targets for known drugs especially in the field of poorly addressed therapeutic areas. Drug discovery largely depends on the identification of potential binding molecules to the intended biomolecular target(s). In this regard, current study was devoted to in silico repurposing of 263 small molecule CNS drugs to achieve superior binders to some MS-related targets. On the basis of molecular docking scores, thioxanthene and benzisothiazole-based antipsychotics could be identified as potential binders to sphingosine-1-phosphate lyase (S1PL) and cyclophilin D (CypD). Tightest interaction modes were observed for zuclopenthixol-S1PL (ΔG_b -7.96 kcal/mol) and lurasidone-CypD (ΔG_b -8.84 kcal/mol) complexes. Molecular dynamics (MD) simulations proved the appropriate and stable accommodation of top-ranked drugs inside enzyme binding sites during 100 ns. Hydroxyethyl piperazine of zuclopenthixol and benzisothiazole of lurasidone flipped inside the binding pocket to interact with adjacent polar and apolar residues. Solvent accessible surface area (SASA) fluctuations confirmed the results of binding trajectory analysis and showed that non-polar hydrophobic interactions played significant roles in acquired stabilities. Our results on lurasidone binding pattern were interestingly in accordance with previous reports on X-ray structures of other norbornane maleimide derivatives as CypD inhibitors. According to this, Asn144, Phe102 and Phe155 served as important residues in providing stable binding pose of lurasidone through both exo and endo conformations. Although experimental results are necessary to be achieved, the outcomes of this study proposed the potentiality of some thioxanthene and benzisothiazole-based antipsychotics for binding to S1PL and CypD, respectively, as MS-related targets.

Regulation of the immune system by the insulin receptor in health and disease

The signaling pathways downstream of the insulin receptor (InsR) are some of the most evolutionarily conserved pathways that regulate organism longevity and metabolism. InsR signaling is well characterized in metabolic tissues, such as liver, muscle, and fat, actively orchestrating cellular processes, including growth, survival, and nutrient metabolism. However, cells of the immune system also express the InsR and downstream signaling machinery, and there is increasing appreciation for the involvement of InsR signaling in shaping the immune response. Here, we summarize current understanding of InsR signaling pathways in different immune cell subsets and their impact on cellular metabolism, differentiation, and effector versus regulatory function. We also discuss mechanistic links between altered InsR signaling and immune dysfunction in various disease settings and conditions, with a focus on age related conditions, such as type 2 diabetes, cancer and infection vulnerability.

Regulatory T cells promote functional recovery after spinal cord injury by alleviating microglia inflammation via STAT3 inhibition

BACKGROUND

Immediately after spinal trauma, immune cells, and proinflammatory cytokines infiltrate the spinal cord and disrupt the focal microenvironment, which impedes axon regeneration and functional recovery. Previous studies have reported that regulatory T cells (Tregs) enter the central nervous system and exert immunosuppressive effects on microglia during multiple sclerosis and stroke. However, whether and how Tregs interact with microglia and modulate injured microenvironments after spinal cord injury (SCI) remains unknown.

METHOD

Regulatory T cells spatiotemporal characteristics were analyzed in a mouse contusion SCI model. Microglia activation status was evaluated by immunostaining and RNA sequencing. Cytokine production in injured spinal cord was examined using Luminex. The role of STAT3 in Treg-microglia crosstalk was investigated in a transwell system with isolated Tregs and primary microglia.

RESULTS

Regulatory T cells infiltration of the spinal cord peaked on day 7 after SCI. Treg depletion promoted microglia switch to a proinflammatory phenotype. Inflammation-related genes, such as ApoD, as well as downstream cytokines IL-6 and TNF-α were upregulated in microglia in Treg-depleted mice. STAT3 inhibition was involved in Treg-microglia crosstalk, and STAT3 chemical blockade improved function recovery in Treg-depleted mice.

CONCLUSION

Our results suggest that Tregs promote functional recovery after SCI by alleviating microglia inflammatory reaction via STAT3.

Insulin-like growth factor-1 receptor controls the function of CNS-resident macrophages and their contribution to neuroinflammation

Signaling by insulin-like growth factor-1 (IGF-1) is essential for the development of the central nervous system (CNS) and regulates neuronal survival and myelination in the adult CNS. In neuroinflammatory conditions including multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE), IGF-1 can regulate cellular survival and activation in a context-dependent and cell-specific manner. Notwithstanding its importance, the functional outcome of IGF-1 signaling in microglia/macrophages, which maintain CNS homeostasis and regulate neuroinflammation, remains undefined. As a result, contradictory reports on the disease-ameliorating efficacy of IGF-1 are difficult to interpret, together precluding its potential use as a therapeutic agent. To fill this gap, we here investigated the role of IGF-1 signaling in CNS-resident microglia and border associated macrophages (BAMs) by conditional genetic deletion of the receptor Igf1r in these cell types. Using a series of techniques including histology, bulk RNA sequencing, flow cytometry and intravital imaging, we show that absence of IGF-1R significantly impacted the morphology of both BAMs and microglia. RNA analysis revealed minor changes in microglia. In BAMs however, we detected an upregulation of functional pathways associated with cellular activation and a decreased expression of adhesion molecules. Notably, genetic deletion of Igf1r from CNS-resident macrophages led to a significant weight gain in mice, suggesting that absence of IGF-1R from CNS-resident myeloid cells indirectly impacts the somatotropic axis. Lastly, we observed a more severe EAE disease course upon Igf1r genetic ablation, thus highlighting an important immunomodulatory role of this signaling pathway in BAMs/microglia. Taken together, our work shows that IGF-1R signaling in CNS-resident macrophages regulates the morphology and transcriptome of these cells while significantly decreasing the severity of autoimmune CNS inflammation.

IGF1R expression by adult oligodendrocytes is not required in the steady-state but supports neuroinflammation

In the central nervous system (CNS), insulin-like growth factor 1 (IGF-1) regulates myelination by oligodendrocyte (ODC) precursor cells and shows anti-apoptotic properties in neuronal cells in different in vitro and in vivo systems. Previous work also suggests that IGF-1 protects ODCs from cell death and enhances remyelination in models of toxin-induced and autoimmune demyelination. However, since evidence remains controversial, the therapeutic potential of IGF-1 in demyelinating CNS conditions is unclear. To finally shed light on the function of IGF1-signaling for ODCs, we deleted insulin-like growth factor 1 receptor (IGF1R) specifically in mature ODCs of the mouse. We found that ODC survival and myelin status were unaffected by the absence of IGF1R until 15 months of age, indicating that IGF-1 signaling does not play a major role in post-mitotic ODCs during homeostasis. Notably, the absence of IGF1R did neither affect ODC survival nor myelin status upon cuprizone intoxication or induction of experimental autoimmune encephalomyelitis (EAE), models for toxic and autoimmune demyelination, respectively. Surprisingly, however, the absence of IGF1R from ODCs protected against clinical neuroinflammation in the EAE model. Together, our data indicate that IGF-1 signaling is not required for the function and survival of mature ODCs in steady-state and disease.

JAK2 inhibitor ameliorates the progression of experimental autoimmune myasthenia gravis and balances Th17/Treg cells via regulating the JAK2/STAT3-AKT/mTOR signaling pathway

BACKGROUND

An imbalance in Th17/regulatory T (Treg) cells is the major pathogenic mechanism underlying myasthenia gravis (MG). JAK2 inhibitors selectively inhibit JAK2 and reduce inflammatory responses. However, there have been no studies examining the therapeutic effects of JAK2 inhibitors in the context of MG.

METHODS

Here, an experimental autoimmune MG (EAMG) rat model was established to explore the therapeutic effect of JAK2 inhibitors on EAMG rats immunized with the AChR α-subunit (97-116 peptide). A JAK2 inhibitor was administered to EAMG rats both in vivo and in vitro. The following experimental methods were used to evaluate the effects of JAK2 inhibitors. The behavioral scores and body weights of the rats were assessed on alternate days. Serum anti-AChR (97-116) IgG and cytokine levels were detected using ELISA. CD4⁺ T cell subsets and related transcription factors in mononuclear cells were detected using flow cytometry and qPCR, respectively. The expression levels of protein molecules in the signaling pathway were detected by western blotting, and the neuromuscular junctions were observed using immunofluorescence.

RESULTS

The results revealed that JAK2 inhibitors could regulate Th17/Treg balance in vivo and in vitro. JAK2 inhibitors reduced the immune response in EAMG rats (including reducing pro-inflammatory cytokines and postsynaptic membrane complement deposition), improved clinical symptoms, and increased AChR aggregation in the postsynaptic membrane. Meanwhile, this study demonstrated that JAK2 inhibitor treatment suppressed the phosphorylation of JAK2/STAT3 and AKT/mTOR pathways and decreased the expression level of the IL-23 receptor.

CONCLUSIONS

This study reveals that there is crosstalk between the JAK2/STAT3 and AKT/mTOR pathways in EAMG rats. JAK2 inhibitors can ameliorate EAMG by regulating Th17/Treg balance by inhibiting both signaling pathways. Our study provides new potential therapeutic targets for MG immunotherapy.

Insulin Receptor Substrate 1 Signaling Inhibits Foxp3 Expression and Suppressive Functions in Treg Cells through the mTORC1 Pathway

Regulatory T (Treg) cells play an important role in immune homeostasis by inhibiting cells within the innate and adaptive immune systems; therefore, the stability and immunosuppressive function of Treg cells need to be maintained. In this study, we found that the expression of insulin receptor substrate 1 (IRS1) by Treg cells was lower than that by conventional CD4 T cells. IRS1-overexpressing Treg cells showed the downregulated expression of FOXP3, as well as Treg signature markers CD25 and CTLA4. IRS1-overexpressing Treg cells also showed diminished immunosuppressive functions in an in vitro suppression assay. Moreover, IRS1-overexpressing Treg cells were unable to suppress the pathogenic effects of conventional T cells in a transfer-induced colitis model. IRS1 activated the mTORC1 signaling pathway, a negative regulator of Treg cells. Moreover, IRS1 destabilized Treg cells by upregulating the expression of IFN-γ and Glut1. Thus, IRS1 acts as a negative regulator of Treg cells by downregulating the expression of FOXP3 and disrupting stability.

In Silico Drug Repurposing in Multiple Sclerosis Using scRNA-Seq Data

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system still lacking a cure. Treatment typically focuses on slowing the progression and managing MS symptoms. Single-cell transcriptomics allows the investigation of the immune system-the key player in MS onset and development-in great detail increasing our understanding of MS mechanisms and stimulating the discovery of the targets for potential therapies. Still, de novo drug development takes decades; however, this can be reduced by drug repositioning. A promising approach is to select potential drugs based on activated or inhibited genes and pathways. In this study, we explored the public single-cell RNA data from an experiment with six patients on single-cell RNA peripheral blood mononuclear cells (PBMC) and cerebrospinal fluid cells (CSF) of patients with MS and idiopathic intracranial hypertension. We demonstrate that AIM2 inflammasome, SMAD2/3 signaling, and complement activation pathways are activated in MS in different CSF and PBMC immune cells. Using genes from top-activated pathways, we detected several promising small molecules to reverse MS immune cells' transcriptomic signatures, including AG14361, FGIN-1-27, CA-074, ARP 101, Flunisolide, and JAK3 Inhibitor VI. Among these molecules, we also detected an FDA-approved MS drug Mitoxantrone, supporting the reliability of our approach.

Oral Corticosteroids for Teprotumumab-Related Hearing Loss: A Case Report

Teprotumumab is a novel insulin-like growth factor-1 receptor inhibitor approved for the treatment of thyroid eye disease, but growing reports of hearing loss require further investigation. To date, an effective protocol for managing hearing loss in this setting has not been determined. Here, we present the first report of the resolution of teprotumumab-related hearing loss with prompt oral prednisone. A 70-year-old woman on teprotumumab experienced sudden hearing loss and tinnitus after her first infusion. An audiogram demonstrated a mild down-sloping to moderately severe mixed conductive and sensorineural hearing loss that was promptly treated with prednisone 60 mg for 6 days with a 1-week gradual taper. An audiogram 3 weeks later demonstrated return of hearing to normal thresholds, and the whole teprotumumab treatment course was completed without further issue. This case highlights the importance of audiometric monitoring, prompt identification of hearing symptoms, and the potential for oral steroids to reverse teprotumumab-related hearing loss.

Elucidating the Heterogeneity of Serum Metabolism in Patients with Myelodysplastic Syndrome and Acute Myeloid Leukemia by Raman Spectroscopy

Myelodysplastic syndrome (MDS) is difficult to diagnose and classify because it has the potential to evolve into acute myeloid leukemia (AML). Raman spectroscopy and orthogonal partial least squares discrimination analysis (OPLS-DA) are used to systematically analyze peripheral blood serum samples from 33 patients with MDS, 25 patients with AML, and 29 control volunteers to gain insight into the heterogeneity of serum metabolism in patients with MDS and AML. AML patients show unique serum spectral data compared to MDS patients with considerably greater peak intensities of collagen (859 and 1345 cm^-1) and carbohydrate (920 and 1123 cm^-1) compared to MDS patients. Screening and bioinformatics analysis of MDS- and AML-related genes based on the Gene Expression Omnibus (GEO) database shows that 1459 genes are differentially expressed, and the main signaling pathways are related to Th17 cell differentiation, pertussis, and cytokine receptor interaction. Statistical analysis of serological indexes related to glucose and lipid metabolism shows that patients with AML have increased serum triglyceride (TG) levels and decreased total protein levels. This study provides a spectral basis for the relationship between the massive serological data of patients and the typing of MDS and AML and provides important information for the rapid and early identification of MDS and AML.

Growth hormone-releasing hormone receptor signaling in experimental ocular inflammation and neuroprotection

Both inflammation and anti-inflammation are involved in the protection of retinal cells. Antagonists of the hypothalamic growth hormone-releasing hormone receptor (GHRHR) have been shown to possess potent anti-inflammatory properties in experimental disease models of various organs, some with systemic complications. Such effects are also found in ocular inflammatory and neurologic injury studies. In experimental models of mice and rats, both growth hormone-releasing hormone receptor agonists and antagonists may alleviate death of ocular neural cells under certain experimental conditions. This review explores the properties of growth hormone-releasing hormone receptor agonists and antagonists that lead to its protection against inflammatory responses induced by extrinsic agents or neurologic injures in ocular animal models.

Metabolic regulation and function of T helper cells in neuroinflammation

Neuroinflammatory conditions such as multiple sclerosis (MS) are initiated by pathogenic immune cells invading the central nervous system (CNS). Autoreactive CD4⁺ T helper cells are critical players that orchestrate the immune response both in MS and in other neuroinflammatory autoimmune diseases including animal models that have been developed for MS. T helper cells are classically categorized into different subsets, but heterogeneity exists within these subsets. Untangling the more complex regulation of these subsets will clarify their functional roles in neuroinflammation. Here, we will discuss how differentiation, immune checkpoint pathways, transcriptional regulation and metabolic factors determine the function of CD4⁺ T cell subsets in CNS autoimmunity. T cells rely on metabolic reprogramming for their activation and proliferation to meet bioenergetic demands. This includes changes in glycolysis, glutamine metabolism and polyamine metabolism. Importantly, these pathways were recently also implicated in the fine tuning of T cell fate decisions during neuroinflammation. A particular focus of this review will be on the Th17/Treg balance and intra-subset functional states that can either promote or dampen autoimmune responses in the CNS and thus affect disease outcome. An increased understanding of factors that could tip CD4⁺ T cell subsets and populations towards an anti-inflammatory phenotype will be critical to better understand neuroinflammatory diseases and pave the way for novel treatment paradigms.

Immunometabolism of macrophages regulates skeletal muscle regeneration

Sarcopenia is an age-related progressive loss of skeletal muscle mass, quality, and strength disease. In addition, sarcopenia is tightly correlated with age-associated pathologies, such as sarcopenic obesity and osteoporosis. Further understanding of disease mechanisms and the therapeutic strategies in muscle regeneration requires a deeper knowledge of the interaction of skeletal muscle and other cells in the muscle tissue. Skeletal muscle regeneration is a complex process that requires a series of highly coordinated events involving communication between muscle stem cells and niche cells, such as muscle fibro/adipogenic progenitors and macrophages. Macrophages play a critical role in tissue regeneration and the maintenance of muscle homeostasis by producing growth factors and cytokines that regulate muscle stem cells and myofibroblast activation. Furthermore, the aging-related immune dysregulation associated with the release of trophic factors and the polarization in macrophages transiently affect the inflammatory phase and impair muscle regeneration. In this review, we focus on the role and regulation of macrophages in skeletal muscle regeneration and homeostasis. The aim of this review is to highlight the important roles of macrophages as a therapeutic target in age-related sarcopenia and the increasing understanding of how macrophages are regulated will help to advance skeletal muscle regeneration.

IGF1R signalling is a guardian of self-tolerance restricting autoantibody production

Objective

Insulin-like growth factor 1 receptor (IGF1R) acts at the crossroad between immunity and cancer, being an attractive therapeutic target in these areas. IGF1R is broadly expressed by antigen-presenting cells (APC). Using mice immunised with the methylated albumin from bovine serum (BSA-immunised mice) and human CD14⁺ APCs, we investigated the role that IGF1R plays during adaptive immune responses.

Methods

The mBSA-immunised mice were treated with synthetic inhibitor NT157 or short hairpin RNA to inhibit IGF1R signalling, and spleens were analysed by immunohistology and flow cytometry. The levels of autoantibody and cytokine production were measured by microarray or conventional ELISA. The transcriptional profile of CD14⁺ cells from blood of 55 patients with rheumatoid arthritis (RA) was analysed with RNA-sequencing.

Results

Inhibition of IGF1R resulted in perifollicular infiltration of functionally compromised S²⁵⁶-phosphorylated FoxO1⁺ APCs, and an increased frequency of IgM⁺CD21⁺ B cells, which enlarged the marginal zone (MZ). Enlargement of MHCII⁺CD11b⁺ APCs ensured favourable conditions for their communication with IgM⁺ B cells in the MZ. The reduced expression of ICOSL and CXCR5 by APCs after IGF1R inhibition led to impaired T cell control, which resulted in autoreactivity of extra-follicular B cells and autoantibody production. In the clinical setting, the low expression of IGF1R on CD14⁺ APCs was associated with an involuted FOXO pathway, non-inflammatory cell metabolism and a high IL10 production characteristic for tolerogenic macrophages. Furthermore, autoantibody positivity was associated with low IGF1R signalling in CD14⁺ APCs.

Conclusions

In experimental model and in patient material, this study demonstrates that IGF1R plays an important role in preventing autoimmunity. The study raises awareness of that immune tolerance may be broken during therapeutic IGF1R targeting.