The biology of innate lymphoid cells

Pathophysiology of bone remodelling cycle: Role of immune system and lipids

Osteoporosis is the most common skeletal disease worldwide, characterized by low bone mineral density, resulting in weaker bones, and an increased risk of fragility fractures. The maintenance of bone mass relies on the precise balance between bone synthesis and resorption. The close relationship between the immune and skeletal systems, called "osteoimmunology", was coined to identify these overlapping "scientific worlds", and its function resides in the evaluation of the mutual effects of the skeletal and immune systems at the molecular and cellular levels, in both physiological and pathological states. Lipids play an essential role in skeletal metabolism and bone health. Indeed, bone marrow and its skeletal components demand a dramatic amount of daily energy to control hematopoietic turnover, acquire and maintain bone mass, and actively being involved in whole-body metabolism. Statins, the main therapeutic agents in lowering plasma cholesterol levels, are able to promote osteoblastogenesis and inhibit osteoclastogenesis. This review is meant to provide an updated overview of the pathophysiology of bone remodelling cycle, focusing on the interplay between bone, immune system and lipids. Novel therapeutic strategies for the management of osteoporosis are also discussed.

IL-17A-producing NKp44(-) group 3 innate lymphoid cells accumulate in Familial Adenomatous Polyposis duodenal tissue

Familial adenomatous polyposis (FAP) is an inherited gastrointestinal syndrome associated with duodenal adenoma formation. Even among carriers of the same genetic variant, duodenal phenotypes vary, indicating that additional factors, such as the local immune system, play a role. We observe an increase in duodenal IL-17A(+)NKp44(-) innate lymphoid type 3 cell (ILC3) in FAP, localized near the epithelium and enriched in adenomas and carcinomas. Elevated IL1B, IL23A, and DLL4 transcript levels correlate with IL-17A(+)NKp44(-)ILC3 accumulation, and in vitro studies with duodenal organoids confirmed this relationship. Bulk RNA sequencing reveals upregulated Reactive oxygen species (ROS)-inducing enzymes DUOX2 and DUOXA2 in FAP adenomas. IL-17A-stimulated FAP organoids show increased DUOX2/DUOXA2 expression, Duox2 protein, and ROS production, leading to DNA damage, suggesting a mechanism by which these immune cells promote tumorigenesis. These findings suggest IL-17A(+)NKp44(-)ILC3s may contribute to a local environment that makes the epithelium more submissive for oncogenic transformation in FAP.

Brusatol ameliorates intestinal mucosal injury in ulcerative colitis via activating IL-22/STAT3 pathway

Brusatol (BR) is an active compounds isolated from Brucea javanica, a Chinese herbal medicine that is famous for its anti-diarrheal effect. We have previously reported that BR mitigated inflammation in murine ulcerative colitis (UC) models. However, BR's role in intestinal mucosal healing, which is recently established as central strategy for the prevention and treatment of UC, remains unknown. In this study, the ameliorative effect of BR on intestinal mucosal damage was investigated in DSS-induced UC mice. BR significantly alleviated colitis symptoms, improved intestinal barrier function by preventing loss of goblet cells and downregulation of mucins and tight junction proteins, as well as maintained proliferative and apoptotic homeostasis in the colonic epithelium of UC mice. Mechanistically, BR enhanced the level and secretion of IL-22, but inhibited IL-22BP, an inhibitory protein of IL-22, in the blood serum and intestinal tissues of UC mice, as well as in MNK3 cells which is an effective cell model for studying ILC3s. Additionally, BR elevated the expressions of receptors for IL-22 (IL-10R2 and IL-22R1), and activated its downstream STAT3 signaling pathway. Furthermore, the involvement of IL-22 was further investigated by using recombinant IL-22 (rIL-22) and IL-22 antibody (anti-IL-22). BR demonstrated comparable effects with rIL-22 on alleviating intestinal inflammation and repairing intestinal mucosal injury. Treatment with anti-IL-22 abrogated the mucosal protective effects of BR. The present findings shed novel insights into the role of BR in intestinal mucosal healing via activating IL-22/STAT3 signaling pathway in UC.

A vasculature-resident innate lymphoid cell population in mouse lungs

Tissue-resident immune cells such as innate lymphoid cells (ILC) are known to reside in the parenchymal compartments of tissues and modulate local immune protection. Here we use intravascular cell labeling, parabiosis and multiplex 3D imaging to identify a population of group 3 ILCs in mice that are present within the intravascular space of lung blood vessels (vILC3). vILC3s are distributed broadly in alveolar capillary beds from which inhaled pathogens enter the lung parenchyma. By contrast, conventional ILC3s in tissue parenchyma are enriched in lymphoid clusters in proximity to large veins. In a mouse model of pneumonia, Pseudomonas aeruginosa infection results in rapid vILC3 expansion and production of chemokines including CCL4. Blocking CCL4 in vivo attenuates neutrophil recruitment to the lung at the early stage of infection, resulting in prolonged inflammation and delayed bacterial clearance. Our findings thus define the intravascular space as a site of ILC residence in mice, and reveal a unique immune cell population that interfaces with tissue alarmins and the circulating immune system for timely host defense.

Baicalin restores innate lymphoid immune imbalance during exacerbation of COPD

Chronic obstructive pulmonary disease (COPD) is characterized by immune dysregulation, including altered innate lymphoid cell (ILC) immune responses, particularly during exacerbations (ECOPD). Baicalin, a natural compound prevalent in various herbal medicines, has shown promise as a therapeutic candidate in ECOPD. However, its potential and molecular mechanism for addressing ILC immune imbalance during ECOPD remain poorly understood. First, this study conducted a cross-sectional analysis of ILC immune responses in stable COPD patients and those experiencing exacerbations. Then, clinical findings of skewed ILC immunity were validated in cigarette smoke and lipopolysaccharide-induced ECOPD mouse models. Lastly, the therapeutic effect of baicalin on restoring ILC immune homeostasis was investigated in experimental ECOPD mouse models. Significant downregulation of ILC2 immunity was observed during COPD exacerbations, accompanied by increased ILC1 and ILC3 responses, particularly in cases associated with bacterial infections. Notably, elevated IL-22 levels were observed in this group. Administration of recombinant IL-22 in ECOPD mouse models disrupted lung ILC homeostasis, specifically inhibiting the accumulation of ILC2. Proteomics and transcriptomics analyses suggested IL-22 as a mediator of type 2 immune suppression by creating a molecular environment that favors type 1 and type 3 immunity. Treatment with baicalin effectively restored ILC2 immunity by enhancing the recruitment and activation of lung ILC2 while suppressing ILC1 and ILC3 responses. Importantly, baicalin attenuated IL-22 production from lung ILC3, highlighting its potential as an IL-22 inhibitor. Baicalin demonstrates potential as a therapeutic strategy for addressing ILC immune imbalance in COPD exacerbations, particularly by restoring ILC2 immunity and partially inhibiting IL-22 production. Clinical registration The cross-sectional study was registered with the Chinese Clinical Trial Registry (ChiCTR2100050683).

Emerging Role of the p53 Pathway in Modulating NK Cell-Mediated Immunity

The p53 pathway plays an important role in role in cancer immunity. Mutation or downregulation of the proteins in the p53 pathway are prevalent in many cancers, contributing to tumor progression and immune dysregulation. Recent findings suggest that the activity of p53 within tumor cells, immune cells, and the tumor microenvironment can play an important role in modulating NK cell-mediated immunity. Consequently, efforts to restore p53 pathway activity are being actively pursued to modulate this form of immunity. This review focuses on p53 activity regulating the infiltration and activation of NK cells in the tumor immune microenvironment. Furthermore, the impact of p53 and its regulation of NK cells on immunogenic cell death within solid tumors and the abscopal effect are reviewed. Finally, future avenues for therapeutically restoring p53 activity to improve NK cell-mediated antitumor immunity and optimize the effectiveness of cancer therapies are discussed.

There's no place like home: How local tissue microenvironments shape the function of innate lymphoid cells

Innate lymphoid cells (ILC) have emerged as critical immune effectors with key roles in orchestrating the wider immune response. While ILC are relatively rare cells they are found enriched within discrete microenvironments, predominantly within barrier tissues. An emerging body of evidence implicates complex and multi-layered interactions between cell types, tissue structure and the external environment as key determinants of ILC function within these niches. In this review we will discuss the specific components that constitute ILC-associated microenvironments and consider how they act to determine health and disease. The development of holistic, integrated models of ILC function within complex tissue environments will inform new understanding of the contextual cues and mechanisms that determine the protective versus disease-causing roles of this immune cell family.

Preoperative blood neutrophil-to-lymphocyte ratio, hematocrit and fibrinogen predict prognosis in colorectal cancer

OBJECTIVE

To investigate the prognostic potential of preoperative blood neutrophil to lymphocyte ratio (NLR), hematocrit (HCT) and Fibrinogen (FIB) level in patients with colorectal cancer (CRC).

METHODS

The data of 268 patients with CRC who underwent radical surgery from March 2013 to August 2017 in the First Affiliated Hospital of Guangzhou Medical University (Guangzhou, China) were retrospectively collected. The correlations between preoperative blood NLR, HCT and FIB level and the clinicopathologic features and prognosis were explored by Cox regression in the patients with CRC.

RESULTS

Univariate and multivariate analyses identified preoperative blood with high NLR (HR = 2.265, 95% CI: 1.437-3.570), low HCT (HR = 1.575, 95% CI: 1.010-2.454), and high FIB (HR = 1.667, 95% CI: 1.067-2.605) as independent predictors of reduced 5-year overall survival (OS). Furthermore, the patients were stratified into high (with 3 predictors), middle (with 2 predictors) and low (with 0 or 1 predictors) risk groups according to the number of the 3 independent prognostic predictors. The more independent predictors a patient has, the poorer their prognosis tends to be.

CONCLUSIONS

Preoperative NLR, HCT, and FIB serve as cost-effective prognostic biomarkers in CRC. Their combination enables precise risk stratification, guiding personalized postoperative management.

The maternal-fetal interface at single-cell resolution: uncovering the cellular anatomy of the placenta and decidua

The maternal-fetal interface represents a critical site of immunological interactions that can greatly influence pregnancy outcomes. The unique cellular composition and cell-cell interactions taking place within these tissues has spurred substantial research efforts focused on the maternal-fetal interface. With the recent advent of single-cell technologies, multiple investigators have applied such methods to gain an unprecedented level of insight into maternal-fetal communication. Here, we provide an overview of the dynamic cellular composition and cell-cell communications at the maternal-fetal interface as reported by single-cell investigations. By primarily focusing on data from pregnancies in the second and third trimesters, we aim to showcase how single-cell technologies have bolstered the foundational understanding of each cell's contribution to physiologic gestation. Indeed, single-cell technologies have enabled the examination of classical placental cells, such as the trophoblast, as well as uncovered new roles for structural cells now recognized as active participants in pregnancy and parturition, such as decidual and fetal stromal cells, which are reviewed herein. Furthermore, single-cell data investigating the ontogeny, function, differentiation, and interactions among immune cells present at the maternal-fetal interface, namely macrophages, T cells, dendritic cells, neutrophils, mast cells, innate lymphoid cells, natural killer cells, and B cells are discussed in this review. Moreover, a key output of single-cell investigations is the inference of cell-cell interactions, which has been leveraged to not only dissect the intercellular communications within specific tissues but also between compartments such as the decidua basalis and placental villi. Collectively, this review emphasizes the ways by which single-cell technologies have expanded the understanding of cell composition and cellular processes underlying pregnancy in mid-to-late gestation at the maternal-fetal interface, which can prompt their continued application to reveal new pathways and targets for the treatment of obstetrical disease.

Association of overweight/obesity and insulin resistance with activation of circulating innate lymphoid cells in women after gestational diabetes mellitus

Introduction

Women with a history of gestational diabetes mellitus (GDM) are at high risk of developing prediabetes or type 2 diabetes later in life. Recent studies have highlighted the regulation and function of innate lymphoid cells (ILCs) in metabolic homeostasis. However, the multifactorial impact of both overweight/obesity and GDM on the immunological profile of circulating ILCs and the progression to prediabetes are not yet fully elucidated.

Methods

Blood samples from 42 women with a history of insulin-treated GDM (GDMi), 33 women with a history of GDM without insulin treatment during pregnancy (GDM), and 45 women after a normoglycemic pregnancy (Ctrl) participating in the ongoing observational PPSDiab study were analyzed by flow cytometry for markers of ILC subsets at the baseline visit (3-16 months postpartum; Visit 1) and 5 years postpartum (58-66 months postpartum; Visit 2).

Results

During the first 5 years postpartum, 18 women of the GDMi group (42.8%), 10 women of the GDM group (30.3%), and 8 participants of the Ctrl group (17.8%) developed prediabetes, respectively. Total circulating type 1 innate lymphoid cells (ILC1s) and NK cell numbers as well as percent HLA-DR+ ILC1s were increased in GDMi versus GDM and Ctrl women both at the baseline visit and the 5-year follow-up. Although ILC subsets at Visit 1 could not predict the progression from GDM to prediabetes, ILC2 frequency was associated with insulin sensitivity index (ISI), whereas percent HLA-DR+ ILC1s were inversely correlated. Moreover, circulating leukocytes and total NK cells were associated with waist circumference and fat mass both at Visit 1 and Visit 2.

Discussion

Our findings introduce human ILCs as a potential therapeutic target deserving further exploration.

Trial registration

Study ID 300-11.

Postprandial parasympathetic signals promote lung type 2 immunity

Lung type 2 immunity protects against pathogenic infection, but its dysregulation causes asthma. Although it has long been observed that symptoms of asthmatic patients often become exaggerated following food intake, the pathophysiological mechanism underlying this postprandial phenomenon is incompletely understood. Here, we report that lung type 2 immunity in mice is enhanced after feeding, which correlates with parasympathetic activation. Also, local parasympathetic innervations exhibit spatial engagement with such immune responses mediated by group 2 innate lymphoid cells (ILC2s). Pharmacologic or surgical blockage of parasympathetic signals diminishes lung type 2 immunity. Conversely, chemogenetic manipulation of parasympathetic inputs and their upstream neurocircuit is sufficient to modulate those immune responses. We then show that the cholinergic receptor muscarinic 4 (Chrm4) for the parasympathetic neurotransmitter acetylcholine is expressed in mouse or human lung ILC2s, and the Chrm4 deletion mitigates ILC2-mediated lung inflammation. These results have revealed a critical neuroimmune function of the gut-brain-lung reflex.

Immunogenicity and Protective Efficacy of an mRNA Vaccine Targeting HSV-2 UL41 in Mice

BACKGROUND

Herpes simplex virus 2 (HSV-2) is the primary cause of sexually transmitted genital ulcerative diseases, for which no effective prophylactic vaccine is currently available. However, the identification of appropriate targets for an HSV-2 mRNA vaccine remains an area requiring further investigation.

METHODS

The immunogenicity and protective effects of an HSV-2 UL41 mRNA vaccine were evaluated in a BALB/c mouse model. The mice were intramuscularly immunized twice, followed by HSV-2 infection at 28 days post boost. Clinical signs were monitored daily, and the viral load and tissue inflammation were assessed on days 1, 4, and 7 post infection. Dendritic cell (DC) activation in spleen tissue was analyzed via transcriptome sequencing.

RESULTS

A comparison of the clinical, immunological, and pathological characteristics of the groups that were immunized with the UL41 mRNA vaccine and then infected with HSV2, along with the control groups, revealed that the vaccine elicited both cellular and humoral immunity, inhibited viral replication, suppressed the inflammatory response, and provided protective effects against the virus in vivo. Furthermore, in vitro assays of DC expansion revealed that the vaccine immunization increased the induction of DCs from splenic cells. Transcriptomic analysis of these DCs revealed the activation of immune signaling pathways.

CONCLUSIONS

Our study suggests that the UL41 mRNA vaccine may provide effective protection against HSV-2-related diseases and holds promise as a potential mRNA vaccine candidate.

Design, current states, and challenges of nanomaterials in anti-neuroinflammation: A perspective on Alzheimer's disease

Alzheimer's disease (AD), an age-related neurodegenerative disease, brings huge damage to the society, to the whole family and even to the patient himself. However, until now, the etiological factor of AD is still unknown and there is no effective treatment for it. Massive deposition of amyloid-beta peptide(Aβ) and hyperphosphorylation of Tau proteins are acknowledged pathological features of AD. Recent studies have revealed that neuroinflammation plays a pivotal role in the pathology of AD. With the rise of nanomaterials in the biomedical field, researchers are exploring how the unique properties of these materials can be leveraged to develop effective treatments for AD. This article has summarized the influence of neuroinflammation in AD, the design of nanoplatforms, and the current research status and inadequacy of nanomaterials in improving neuroinflammation in AD.

Enteric GABAergic neuron-derived γ-aminobutyric acid initiates expression of Igfbp7 to sustain ILC3 homeostasis

Neuronal signals have emerged as critical factors that regulate group 3 innate lymphoid cell (ILC3) response and tissue homeostasis, but the molecular mechanisms underlying this regulation remain largely elusive. Here, we identified that the enteric GABAergic neuron-derived neurotransmitter γ-aminobutyric acid (GABA) inhibited proliferation and IL-17A production in ILC3s in a manner dependent on the GABA receptors Gabbr1 and Gabbr2. Conditional deletion of Gabbr1 or ablation of GABAergic neurons caused increased IL-17A production and aggravated colitis. Mechanistically, GABA suppressed the expression of the LIP isoform of the transcription factor C/EBP-β in ILC3s, which repressed the transcription of Igfbp7, which encodes the secreted factor Igfbp7. Autocrine Igfbp7 signaling through the receptor Igf1R inhibited ILC3 proliferation and IL-17A production. Suppression of signaling through the GABA-C/EBP-β-IGFBP7 pathway highly correlated with severity of intestinal inflammation in patients with inflammatory bowel disease (IBD). Collectively, our findings describe an important molecular mechanism underlying the maintenance of gut immune homeostasis.

Natural killer cells in the lung: novel insight and future challenge in the airway diseases

Natural killer (NK) cells are innate lymphoid cells which are present in the lung as circulating and resident cells. They are key players both in airway surveillance and in crosstalk with (COPD) pathogenesis, and they seem to contribute to the development of bronchiectasis. In asthma, NK cell dysfunction was observed mainly in severe forms, and it can lead to a biased type-2 immune response and failure in the resolution of eosinophilic inflammation that characterise both allergic and eosinophilic phenotypes. Moreover, aberrant NK cell functions may interfere with antimicrobial immune response contributing to the frequency and severity of virus-induced exacerbations. In COPD, lung NK cells exhibit increased cytotoxicity against lung epithelium contributing to lung tissue destruction and emphysema. This cell destruction may be exacerbated by viral infections and cigarette smoke exposure through NKG2D-dependent detection of cellular stress. Lastly, in bronchiectasis, the airway NK cells might both promote neutrophil survival following stimulation by proinflammatory cytokines and promote neutrophil apoptosis. Systemic steroid treatment seemingly compromises NK activity, while biologic treatment with benralizumab could enhance NK cell proliferation, maturation and activation. This narrative review gives an overview of NK cells in airway diseases focusing on pathophysiological and clinical implications. Together, our findings emphasise the pleiotropic role of NK cells in airway diseases underscoring their possible implications as to therapeutical approaches.

Innate lymphoid cells in HIV pathogenesis and in the human female genital tract

PURPOSE OF REVIEW

Women are underrepresented in HIV infection and prevention research despite making up half of people living with HIV. The female genital tract (FGT) serves as a primary site of HIV acquisition, but gaps in knowledge remain regarding protective innate immune mechanisms. Innate lymphoid cells are tissue-resident cells involved in mucosal barrier maintenance and protection, and innate lymphoid cells (ILCs) are altered during chronic HIV infection. However, ILCs role in mucosal HIV pathogenesis is unclear and they are poorly characterized in the FGT.

RECENT FINDINGS

Human ILCs differ from their mouse counterparts and plastically adjust to their tissue of residency. Human ILC characterization is difficult due to tissue-specific adaptations and transition between subsets. While evidence for ILC involvement in antiviral activity and barrier maintenance is provided in mouse models, human ILC role in mucosal immunity remain understudied, particularly in the FGT. In chronic HIV/simian immunodeficiency virus (SIV) infection, ILCs are altered in a tissue-specific manner, and SIV models indicate potential for antiviral responses.

SUMMARY

ILCs are tissue-resident plastic cells that provide barrier protection at mucosal surfaces and display antiviral capacity. Considering that HIV is primarily transmitted through mucosal exposure, more research is needed to understand ILC contribution to HIV pathogenesis in human mucosal surfaces relevant for HIV acquisition.

HDAC inhibitors and IBD: Charting new approaches in disease management

Inflammatory bowel disease (IBD) represents a group of chronic inflammatory disorders of the gastrointestinal tract. Despite substantial advances in our understanding of IBD pathogenesis, the currently available therapeutic options remain limited in their efficacy and often come with significant side effects. Therefore, there is an urgent need to explore novel approaches for the management of IBD. One promising avenue of investigation revolves around the use of histone deacetylase (HDAC) inhibitors, which have garnered considerable attention for their potential in modulating gene expression and curbing inflammatory responses. This review emphasizes the pressing need for innovative drugs in the treatment of IBD, and drawing from a wealth of preclinical studies and clinical trials, we underscore the multifaceted roles and the therapeutic effects of HDAC inhibitors in IBD models and patients. This review aims to contribute significantly to the understanding of HDAC inhibitors' importance and prospects in the management of IBD, ultimately paving the way for improved therapeutic strategies in this challenging clinical landscape.

Role of innate immune cells in multiple sclerosis

Multiple sclerosis (MS) is a chronic autoimmune, inflammatory and neurodegenerative disease affecting the central nervous system (CNS). MS is associated with a complex interplay between neurodegenerative and inflammatory processes, mostly attributed to pathogenic T and B cells. However, a growing body of preclinical and clinical evidence indicates that innate immunity plays a crucial role in MS promotion and progression. Accordingly, preclinical and clinical studies targeting different innate immune cells to control MS are currently under study, highlighting the importance of innate immunity in this pathology. Here, we reviewed recent findings regarding the role played by innate immune cells in the pathogenesis of MS. Additionally, we discuss potential new treatments for MS based on targets against innate immune components.

SIRI as a biomarker for bladder neoplasm: Utilizing decision curve analysis to evaluate clinical net benefit

PURPOSE

This analysis aimed to evaluate the clinical relevance of the presurgical systemic inflammation response index (SIRI) in individuals undergoing radical cystectomy (RC).

METHODS

In this retrospective study, 228 were categorized into 2 cohorts depending on their SIRI levels using the best cut-off determined by the Youden Index. The association between SIRI and lymph node metastasis (N), advanced pT stage (pT3/pT4), and loco-regional extended state were analyzed at the time of surgery. Multivariate Cox regression analysis was performed to evaluate the impact of SIRI on time to relapse, tumor-specific survival, and survival rates. The additional medical advantage was evaluated through decision curve analysis (DCA).

RESULTS

High and low SIRI group was obtained using the best cut-off value (1.71×109/l). On multivariate logistic regression analysis, elevated SIRI was significantly associated with advanced pT stage (P = 0.003) and loco-regional extended state (P = 0.003). On multivariable Cox regression models based on presurgical clinicopathological factors, an augmented SIRI was linked to poorer relapse-free survival (RFS) (P = 0.035), with the improvement of the concordance index just for RFS. In DCAs, incorporating SIRI yielded results equal to or better than those of the model without SIRI for all outcomes models. It demonstrated improvements in net benefit at probability thresholds up to 50% for the model adjusted with preoperative factors for RFS and for postoperative factors in CSS and OS.

CONCLUSIONS

SIRI is an innovative prognostic indicator and a potential biomarker that can enhance conventional medical pathological evaluation and improve the personalization of clinical treatment strategies for bladder cancer patients following RC.

Regulation of 5-fluorouracil-induced intestinal damage by the interleukin-23/interleukin-22 axis in chemotherapy

5-Fluorouracil (5-FU) is a primary chemotherapeutic agent for gastrointestinal cancers, known to improve survival but also cause significant intestinal damage, affecting patient quality of life. This study investigated the IL-23-IL-22 axis's role in moderating 5-FU-induced intestinal damage. We analyzed paracancerous tissue damage in colon cancer patients with different Tumor Regression Grade (TRG) and found a direct correlation between TRG and tissue damage severity, indicating that higher chemotherapy effectiveness is linked to increased tissue damage. In a 5-FU-treated mouse model, we observed severe intestinal damage and a reduction in proliferative cells. Transcriptome sequencing and immunofluorescence revealed that myeloid cells in damaged tissues produced IL-23, which activated ILC3s to secrete IL-22, promoting tissue repair and homeostasis. IL-22 supplementation in deficient mice significantly mitigated damage, underscoring the IL-22/IL-23 axis's potential as a therapeutic target to reduce chemotherapy-induced damage and enhance recovery. This research advances understanding of the biochemical responses to chemotherapy and suggests new avenues for developing therapies to maintain intestinal integrity during cancer treatment.

HCNetlas: A reference database of human cell type-specific gene networks to aid disease genetic analyses

Cell type-specific actions of disease genes add a significant layer of complexity to the genetic architecture underlying diseases, obscuring our understanding of disease mechanisms. Single-cell omics have revealed the functional roles of genes at the cellular level, identifying cell types critical for disease progression. Often, a gene impact on disease through its altered network within specific cell types, rather than mere changes in expression levels. To explore the cell type-specific roles of disease genes, we developed HCNetlas (human cell network atlas), a resource cataloging cell type-specific gene networks (CGNs) for various healthy tissue cells. We also devised 3 network analysis methods to investigate cell type-specific functions of disease genes. These methods involve comparing HCNetlas CGNs with those derived from disease-affected tissue samples. These methods find that systemic lupus erythematosus genes predominantly function in myeloid cells, and Alzheimer's disease genes mainly play roles in inhibitory and excitatory neurons. Additionally, they suggest that many lung cancer-related genes may exert their roles in immune cells. These findings suggest that HCNetlas has the potential to link disease-associated genes to cell types of action, facilitating development of cell type-resolved diagnostics and therapeutic strategies for complex human diseases.

The Physiology of Enteric Glia

Enteric glia are the partners of neurons in the enteric nervous system throughout the gastrointestinal tract. Roles fulfilled by enteric glia are diverse and contribute to maintaining intestinal homeostasis through interactions with neurons, immune cells, and the intestinal epithelium. Glial influences optimize physiological gut processes such as intestinal motility and epithelial barrier integrity through actions that regulate the microenvironment of the enteric nervous system, the activity of enteric neurons, intestinal epithelial functions, and immune response. Changes to glial phenotype in disease switch glial functions and contribute to intestinal inflammation, dysmotility, pain, neuroplasticity, and tumorigenesis. This review summarizes current concepts regarding the physiological roles of enteric glial cells and their potential contributions to gut disease. The discussion is focused on recent evidence that suggests important glial contributions to gastrointestinal health and pathophysiology.

NKp46 enhances type 1 innate lymphoid cell proliferation and function and anti-acute myeloid leukemia activity

NKp46 is a critical regulator of natural killer (NK) cell immunity, but its function in non-NK innate immune cells remains unclear. Here, we show that NKp46 is indispensable for expressing IL-2 receptor-α (IL-2Rα) by non-NK liver-resident type-1 innate lymphoid cells (ILC1s). Deletion of NKp46 reduces IL-2Rα on ILC1s by downregulating NF-κB signaling, thus impairing ILC1 proliferation and cytotoxicity in vitro and in vivo. The binding of anti-NKp46 antibody to NKp46 triggers the activation of NF-κB, the expression of IL-2Rα, interferon-γ (IFN-γ), tumor necrosis factor (TNF), proliferation, and cytotoxicity. Functionally, NKp46 expressed on mouse ILC1s interacts with tumor cells through cell-cell contact, increasing ILC1 production of IFN-γ and TNF, and enhancing cytotoxicity. In a mouse model of acute myeloid leukemia, deletion of NKp46 impairs the ability of ILC1s to control tumor growth and reduces survival. This can be reversed by injecting NKp46+ ILC1s into NKp46 knock-out mice. Human NKp46+ ILC1s exhibit stronger cytokine production and cytotoxicity than their NKp46- counterparts, suggesting that NKp46 plays a similar role in humans. These findings identify an NKp46-NF-κB-IL-2Rα axis and suggest that activating NKp46 with an anti-NKp46 antibody may provide a potential strategy for anti-tumor innate immunity.

Tissue-resident immune cells: from defining characteristics to roles in diseases

Tissue-resident immune cells (TRICs) are a highly heterogeneous and plastic subpopulation of immune cells that reside in lymphoid or peripheral tissues without recirculation. These cells are endowed with notably distinct capabilities, setting them apart from their circulating leukocyte counterparts. Many studies demonstrate their complex roles in both health and disease, involving the regulation of homeostasis, protection, and destruction. The advancement of tissue-resolution technologies, such as single-cell sequencing and spatiotemporal omics, provides deeper insights into the cell morphology, characteristic markers, and dynamic transcriptional profiles of TRICs. Currently, the reported TRIC population includes tissue-resident T cells, tissue-resident memory B (BRM) cells, tissue-resident innate lymphocytes, tissue-resident macrophages, tissue-resident neutrophils (TRNs), and tissue-resident mast cells, but unignorably the existence of TRNs is controversial. Previous studies focus on one of them in specific tissues or diseases, however, the origins, developmental trajectories, and intercellular cross-talks of every TRIC type are not fully summarized. In addition, a systemic overview of TRICs in disease progression and the development of parallel therapeutic strategies is lacking. Here, we describe the development and function characteristics of all TRIC types and their major roles in health and diseases. We shed light on how to harness TRICs to offer new therapeutic targets and present burning questions in this field.

T-bet+ILC3 in peripheral blood is increased in the ankylosing spondylitis with high disease activity

Objective

Ankylosing spondylitis (AS) is a chronic autoimmune disease characterized by systemic inflammation, often resulting in fusion of the spine and peripheral joints. This study aimed to investigate the role of innate lymphoid cells (ILCs) in AS patients with high disease activity.

Methods

Blood samples were collected from healthy controls and AS patients categorized by high or low disease activity. Systemic inflammation was quantified through C-reactive protein (CRP) levels and erythrocyte sedimentation rate (ESR), alongside disease activity scores such as Ankylosing Spondylitis Disease Activity Score(ASDAS) and Bath Ankylosing Spondylitis Disease Activity Index(BASDAI). The levels of different ILC subsets and the expression of T-box transcription factor 21 (T-bet) and retinoic-acid-receptor-related orphan receptor gamma (RORγt) in peripheral blood were analyzed via flow cytometry. Additionally, 24 cytokines in plasma were measured using a Luminex liquid suspension chip.

Results

The proportion of total ILCs and the distribution of ILC subsets in peripheral blood varied with AS disease activity scores. Specifically, the frequencies of total ILCs and ILC3s were significantly elevated in AS patients with high disease activity (AS-HA). The frequency and absolute number of ILC3s showed a positively correlation with disease severity scores. Furthermore, T-bet+ILC3s were significantly increased in the AS-HA group. Plasma levels of IL-17A and IFN-γ were positively correlated with the frequency of circulating-ILC3 in AS patients.

Conclusions

These findings highlight the critical role of T-bet+ILC3s in the inflammatory process of AS, suggesting their potential as a therapeutic target for managing AS disease.

Hyperactivity of the IL-33-ILC2s-IL-13-M-MDSCs axis promotes cervical cancer progression

The interleukin-33(IL-33) - group 2 innate lymphoid cells (ILC2s) - interleukin-13(IL-13) - monocytic myeloid-derived suppressor cells (M-MDSCs) axis plays a critical role in promoting immune evasion in tumors; however, its specific function in cervical cancer remains poorly understood. In this study, we observed that the proportion of IL-33-ILC2s-IL-13-M-MDSCs were significantly elevated in both cervical cancer patients and the subcutaneous U14 cervical cancer mouse model, compared to normal controls. Our results suggest that IL-33 stimulates ILC2s to secrete IL-13, which, in turn, regulates M-MDSCs to enhance their immune evasion capabilities. Notably, in vitro blockade of IL-33 and IL-13 partially restored the levels and functions of both ILC2s and M-MDSCs. In conclusion, these findings imply that the overactivation of the IL-33-ILC2s-IL-13-M-MDSCs axis may contribute to cervical cancer progression. However, further in vivo blockade studies are required to fully elucidate the precise mechanisms underlying this interaction and to assess its potential therapeutic implications for cervical cancer.

OMIP-110: A 37-Color Spectral Flow Cytometric Panel to Assess Transcription Factors and Chemokine Receptors in Human Intestinal Lymphoid Cells

We have developed a 37-color spectral flow cytometry panel to assess the phenotypical differentiation of innate and adaptive immune lymphoid subsets within human intestinal tissue. In addition to lineage markers for identifying innate lymphoid cells (ILC), TCRγδ, MAIT (mucosal-associated invariant T), natural killer (NK), CD4+ and CD8+ T cells, we incorporated markers of differentiation and activation (CD45RA, CD45RO, CD25, CD27, CD38, CD39, CD69, CD103, CD127, CD161, HLA-DR, CTLA-4 [CD152]), alongside transcription factors (Bcl-6, FoxP3, GATA-3, Helios, T-bet, PU.1 and RORγt) and chemokine receptors (CCR4, CCR6, CCR7, CXCR3, and CXCR5). Additionally, Granzyme B and Ki-67 were included to assess cytotoxicity and proliferation potential of the different subsets. This panel is currently used for in-depth immunophenotyping in endoscopic biopsies and peripheral blood mononuclear cells (PBMC) from inflammatory bowel disease (IBD) patients. Distinguished from other OMIP papers, the comprehensive detection of both transcription factors and chemokine receptors facilitates the efficient assessment of several subsets, particularly CD4+ T helper cells, and its potential application extends to both tissue and circulation.

Rebalancing immune homeostasis in combating disease: The impact of medicine food homology plants and gut microbiome

BACKGROUND

Gut microbiota plays an important role in multiple human physiological processes and an imbalance in it, including the species, abundance, and metabolites can lead to diseases. These enteric microorganisms modulate immune homeostasis by presenting a myriad of antigenic determinants and microbial metabolites. Medicinal and food homologous (MFH) plants, edible herbal materials for both medicine and food, are important parts of Traditional Chinese Medicine (TCM). MFH plants have drawn much attention due to their strong biological activity and low toxicity. However, the interplay of MFH and gut microbiota in rebalancing the immune homeostasis in combating diseases needs systematic illumination.

PURPOSE

The review discusses the interaction between MFH and gut microbiota, including the effect of MFH on the major group of gut microbiota and the metabolic effect of gut microbiota on MFH. Moreover, how gut microbiota influences the immune system in terms of innate and adaptive immunity is addressed. Finally, the immunoregulatory mechanisms of MFH in regulation of host pathophysiology via gut microbiota are summarized.

METHODS

Literature was searched, analyzed, and collected using databases, including PubMed, Web of Science, and Google Scholar using relevant keywords. The obtained articles were screened and summarized by the research content of MFH and gut microbiota in immune regulation.

RESULTS

The review demonstrates the interaction between MFH and gut microbiota in disease prevention and treatment. Not only do the intestinal microorganisms and intestinal mucosa constitute an important immune barrier of the human body, but also lymphoid tissue and diffused immune cells within the mucosa participate in the response of innate immunity and adaptive immunity. MFH modulates immune regulation by affecting intestinal flora, helps maintain the balance of the immune system and interfere with the occurrence and development of a broad category of diseases.

CONCLUSION

Being absorbed from the gastrointestinal tract, MFH can have profound effects on gut microbiota. In turn, the gut microbiota also actively participate in the bioconversion of complex constituents from MFH, which could further influence their physiological and pharmacological properties. The review deepens the understanding of the relationship among MFH, gut microbiota, immune system, and human diseases and further promotes the progression of additional relevant research.

Monocyte-lymphocyte ratio predicts cardiovascular diseases death in individuals with type 2 diabetes

PURPOSE

Previous studies have shown higher cardiovascular mortality risk with higher monocyte-lymphocyte ratio levels in general population. However, the levels of oxidative stress in individuals with type 2 diabetes are higher than those in the general population, which may affect the link between monocyte-to-lymphocyte ratio and cardiovascular disease deaths. And the association between the monocyte-to-lymphocyte ratio and mortality risk in people with type 2 diabetes still be unknown. This study aimed to investigate the prognostic significance of monocyte-to-lymphocyte ratio in type 2 diabetes.

METHODS

This analysis involved 2,954 individuals with type 2 diabetes from the National Health and Nutrition Examination Survey 1999-2010. The National Death Index records through December 31, 2019, was used to determine all-cause and cardiovascular mortality. The prognostic roles were determined using Cox regression models, restricted cubic spline analysis, and time-dependent receiver operating characteristic curve analysis.

RESULTS

During an average follow-up period of 12.4 years, a total of 1,007 deaths occurred, while 252 were due to cardiovascular disease. An elevated monocyte-to-lymphocyte ratio level exhibited a significant dose-response relationship with an increased risk of all-cause mortality (1.34 [95% CI 1.12, 1.60] for all-cause mortality [P trend = 0.001]). The multivariable-adjusted HR was 1.81 (95% CI 1.25, 2.63) (P trend = 0.001) for cardiovascular mortality indicating a U-shaped relationship (P nonlinear = 0.013).

CONCLUSIONS

The results of this study indicate a U-shaped relationship between the monocyte-to-lymphocyte ratio and cardiovascular mortality in individuals with diabetes. Both very low and high monocyte-to-lymphocyte ratio monocyte-to-lymphocyte ratio values were found to be associated with increased cardiovascular mortality risk.

Utility of lymphocyte-to-monocyte ratio and pretreatment tooth extraction in intra-arterial chemoradiotherapy for oral cancer to prevent osteoradionecrosis of the jaw

The objective of this study was to evaluate the utility of inflammation-based prognostic scores (IBPS) in predicting ORN among patients undergoing superselective intra-arterial chemoradiotherapy (SSIACRT). This retrospective cohort study examined the medical records of 54 patients with advanced oral cancer (stage 3 or 4) treated with SSIACRT. The predictor variable was IBPS. The main outcome variable was onset of ORN. Covariates comprised sex, median age, tooth status, tumor size, and pretreatment tooth extraction with professional oral care (pretreatment tooth extraction). For each factor, cumulative incidence and univariate and multivariate analyses of ORN incidence were performed. The cumulative incidence of ORN in patients with pre-treatment lymphocyte-to-monocyte ratio (LMR < 4.95vs LMR ≥4.95, P = 0.01) and pretreatment tooth extraction (no vs. yes, P = 0.03) was significantly different. Univariate and multivariate analyses identified pre-treatment LMR cutoff values < 4.95 and pre-treatment tooth extraction as significantly associated with the development of ORN. Pretreatment tooth extraction reduced the incidence of ORN in low LMR group (P = 0.04). LMR is a useful biomarker to predict ORN in SSIACRT. Pretreatment tooth extraction was a useful treatment to prevent ORN. Pretreatment extraction with LMR may be important for the prevention of ORN in SSIACRT.

Group 3 Innate Lymphoid Cells: A Potential Therapeutic Target for Steroid Resistant Asthma

Asthma is a chronic airway inflammatory disease that affects millions globally. Although glucocorticoids are a mainstay of asthma treatment, a subset of patients show resistance to these therapies, resulting in poor disease control and increased morbidity. The complex mechanisms underlying steroid-resistant asthma (SRA) involve Th1 and Th17 lymphocyte activity, neutrophil recruitment, and NLRP3 inflammasome activation. Recent studies provided evidence that innate lymphoid cells type 3 (ILC3s) might be potential therapeutic targets for non-eosinophilic asthma (NEA) and SRA. Like Th17 cells, ILC3s play crucial roles in immune responses, inflammation, and tissue homeostasis, contributing to disease severity and corticosteroid resistance in NEA. Biologics targeting ILC3-related pathways have shown promise in managing Th2-low asthma, suggesting new avenues for SRA treatment. This review aims to explore the risk factors for SRA, discuss the challenges and mechanisms underlying SRA, consolidate current findings on innate lymphoid cells, and elucidate their role in respiratory conditions. We present the latest findings on the involvement of ILC3s in human diseases and explore their potential mechanisms in SRA development. Furthermore, we review emerging therapeutic biologics targeting ILC3-related pathways in managing NEA and SRA. This review highlights current challenges, and emerging therapeutic strategies, and addresses a significant gap in asthma research, with implications for improving the management of steroid-resistant asthma.

A double-edged sword role of IFN-γ-producing iNKT cells in sepsis: Persistent suppression of Treg cell formation in an Nr4a1-dependent manner

Sepsis, a leading cause of mortality in intensive care units worldwide, lacks effective treatments for advanced-stage sepsis. Therefore, understanding the underlying mechanisms of this disease is crucial. This study reveals that invariant natural killer T (iNKT) cells have an opposing role in the progression of sepsis by suppressing regulatory T (Treg) cell differentiation and function. The activation of iNKT cells by α-Galcer enhances interferon (IFN)-γ production. Blocking antibodies or transferring IFN-γ-deficient iNKT cells demonstrates that iNKT cells inhibit Treg differentiation through IFN-γ production. Additionally, iNKT cell-mediated Treg inhibition prevents secondary infection caused by Listeria monocytogenes during the post-septic phase. The transcriptomic analysis of Treg cells further reveals that the suppressive function of Tregs is impaired by iNKT cells. Finally, we demonstrate that iNKT cells inhibit Treg differentiation in an Nr4a1-dependent manner. Our data uncover the dual function of iNKT cells in sepsis progression and provide a potential treatment target for this adverse long-term outcome induced by sepsis.

Developmental patterns of intestinal group 3 innate lymphoid cells in piglets and their response to enterotoxigenic Escherichia coli infection

Diarrhoea and preweaning mortality in piglets are crucial factors impacting the economic sustainability of the swine industry. Pathogenic infections are among the main causes of diarrhea and mortality. Group 3 innate lymphoid cells (ILC3s) are crucial for safeguarding against pathogenic infections. However, knowledge regarding the development and function of ILC3s in suckling piglets is currently limited. Our findings demonstrate that the development of ILC3s in suckling piglets gradually progresses from day 1 to day 21, with a notable increase observed on day 28. Additionally, the development of NKp46+ILC3s and the production of interleukin (IL)-17A by ILC3s displayed consistent patterns with the changes observed in ILC3s. Notably, interferon (IFN)-γ levels significantly increased on day 14. Moreover, the production of IFN-γ by NKp46+ILC3s was greater than that by NKp46-ILC3s. Importantly, when piglets were subjected to a 4-h challenge with enterotoxigenic Escherichia coli, both the percentages of ILC3s significantly increased, accompanied by increased IL-22 production, highlighting their importance in maintaining intestinal health. The outcomes of this study provide valuable insights for future related research.

T cell metabolism in kidney immune homeostasis

Kidney immune homeostasis is intricately linked to T cells. Inappropriate differentiation, activation, and effector functions of T cells lead to a spectrum of kidney disease. While executing immune functions, T cells undergo a series of metabolic rewiring to meet the rapid energy demand. The key enzymes and metabolites involved in T cell metabolism metabolically and epigenetically modulate T cells' differentiation, activation, and effector functions, thereby being capable of modulating kidney immune homeostasis. In this review, we first summarize the latest advancements in T cell immunometabolism. Second, we outline the alterations in the renal microenvironment under certain kidney disease conditions. Ultimately, we highlight the metabolic modulation of T cells within kidney immune homeostasis, which may shed light on new strategies for treating kidney disease.

Naturally arising memory-phenotype CD4+ T lymphocytes contain an undifferentiated population that can generate TH1, TH17, and Treg cells

Memory-phenotype (MP) CD4+ T lymphocytes develop from naïve cells via self-recognition at homeostasis. While previous studies defined MP cells as a heterogeneous population that comprises T helper 1 (TH1)/17-like subsets, functional significance of the T-bet- Rorγt- subpopulation remains unknown. Here we show that MP lymphocytes as a whole population can differentiate into TH1/17/regulatory T (Treg) cells to mediate mild and persistent inflammation in lymphopenic environments, whereas naïve cells exhibit strong, TH1-dominated responses. Moreover, we demonstrate that MP lymphocytes comprise not only TH1/17-differentiated subsets but a polyclonal, transcriptomically immature "undifferentiated" subpopulation at homeostasis. Furthermore, our data argue that while the T-bet+ Rorγt- MP subset is terminally TH1-differentiated, its undifferentiated counterpart retains the capacity to rapidly proliferate to differentiate into TH1/17/Treg cells, with the latter response tonically constrained by preexisting Treg cells. Together, our results identify undifferentiated MP CD4+ T lymphocytes as a unique precursor that has a diverse differentiation potential to generate TH1/17/Treg cells to contribute to pathogenesis of inflammation.

RIPK3 and caspase-8 interpret cytokine signals to regulate ILC3 survival in the gut

Group 3 innate lymphoid cells (ILC3s) are abundant in the developing or healthy intestine to critically support tissue homeostasis in response to microbial colonization. However, intestinal ILC3s are reduced during chronic infections, colorectal cancer, or inflammatory bowel disease (IBD), and the mechanisms driving these alterations remain poorly understood. Here we employed RNA sequencing of ILC3s from IBD patients and observed a significant upregulation of RIPK3, the central regulator of necroptosis, during intestinal inflammation. This was modeled in mice where we found that intestinal ILC3s express RIPK3, with conventional (c)ILC3s exhibiting high RIPK3 and low levels of pro-survival genes relative to lymphoid tissue inducer (LTi)-like ILC3s. ILC3-specific RIPK3 is promoted by gut microbiota, further upregulated following enteric infection, and dependent upon IL-23R and STAT3 signaling. However, lineage-specific deletion of RIPK3 revealed a redundant role in ILC3 survival, due to a blockade of RIPK3-mediated necroptosis by caspase 8, which was also activated in response to enteric infection. In contrast, lineage-specific deletion of caspase 8 resulted in loss of cILC3s from the healthy intestine and all ILC3 subsets during enteric infection, which increased pathogen burdens and gut inflammation. This function of caspase 8 required catalytic activity induced by TNF or TL1A and was dispensable if RIPK3 was simultaneously deleted. Caspase 8 activation and cell death were associated with increased Fas on ILC3s, and the Fas-FasL pathway was upregulated by cILC3s during enteric infection, which could restrain the abundance of intestinal ILC3s. Collectively, these data reveal that interpretation of key cytokine signals controls ILC3 survival following microbial challenge, and that an imbalance of these pathways, such as in IBD or across ILC3 subsets, provokes depletion of tissue-protective ILC3s from the inflamed intestine.

Computational exploration of novel ketoprofen derivatives: Molecular dynamics simulations and MM-PBSA calculations for COX-2 inhibition as promising anti-inflammatory drugs

Computer-aided drug design is widely employed to identify novel compounds for therapeutic applications. Ketoprofen (KTP), a commonly used and marketed nonsteroidal anti-inflammatory drug (NSAID), is effective in treating pain, fever, inflammation, and some cancers. In this research, we explored the behavior of six analogues designed by structurally modifying the KTP molecule. Specifically, KTP-A and KTP-B contain a -CN group at the ortho position, KTP-C and KTP-D have a -CN group at the meta position, and KTP-E and KTP-F feature a -CF3 group at the meta position. To assess these analogues, we conducted molecular dynamics simulations (MD) to study their inhibitory effects on human cyclooxygenase 2 (COX-2), providing detailed insights into the structure and dynamics of the protein both with and without ligands. MD simulation, enhanced by technological advances, has proven to be a powerful tool for new drug discovery. We further quantified the binding affinity of these drug molecules toward COX-2 using molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) binding free energy calculations. The dynamic properties were evaluated through analyses of root mean square deviations (RMSD), root mean square fluctuations (RMSF), radius of gyration (Rg), solvent-accessible surface area (SASA), covariance matrix, principal component analysis (PCA), and Gibbs free energy landscapes (FEL). Ultimately, this study confirms that the six KTP derivatives are promising candidates for the treatment of inflammation, with KTP-B standing out as particularly effective.

Immune checkpoint landscape of human atherosclerosis and influence of cardiometabolic factors

Immune checkpoint inhibitor (ICI) therapies can increase the risk of cardiovascular events in survivors of cancer by worsening atherosclerosis. Here we map the expression of immune checkpoints (ICs) within human carotid and coronary atherosclerotic plaques, revealing a network of immune cell interactions that ICI treatments can unintentionally target in arteries. We identify a population of mature, regulatory CCR7+FSCN1+ dendritic cells, similar to those described in tumors, as a hub of IC-mediated signaling within plaques. Additionally, we show that type 2 diabetes and lipid-lowering therapies alter immune cell interactions through PD-1, CTLA4, LAG3 and other IC targets in clinical development, impacting plaque inflammation. This comprehensive map of the IC interactome in healthy and cardiometabolic disease states provides a framework for understanding the potential adverse and beneficial impacts of approved and investigational ICIs on atherosclerosis, setting the stage for designing ICI strategies that minimize cardiovascular disease risk in cancer survivors.

Dynamic regulation of innate lymphoid cell development during ontogeny

The helper-like ILC contains various functional subsets, such as ILC1, ILC2, ILC3 and LTi cells, mediating the immune responses against viruses, parasites, and extracellular bacteria, respectively. Among them, LTi cells are also crucial for the formation of peripheral lymphoid tissues, such as lymph nodes. Our research, along with others', indicates a high proportion of LTi cells in the fetal ILC pool, which significantly decreases after birth. Conversely, the proportion of non-LTi ILCs increases postnatally, corresponding to the need for LTi cells to mediate lymphoid tissue formation during fetal stages and other ILC subsets to combat diverse pathogen infections postnatally. However, the regulatory mechanism for this transition remains unclear. In this study, we observed a preference for fetal ILC progenitors to differentiate into LTi cells, while postnatal bone marrow ILC progenitors preferentially differentiate into non-LTi ILCs. Particularly, this differentiation shift occurs within the first week after birth in mice. Further analysis revealed that adult ILC progenitors exhibit stronger activation of the Notch signaling pathway compared to fetal counterparts, accompanied by elevated Gata3 expression and decreased Rorc expression, leading to a transition from fetal LTi cell-dominant states to adult non-LTi ILC-dominant states. This study suggests that the body can regulate ILC development by modulating the activation level of the Notch signaling pathway, thereby acquiring different ILC subsets to accommodate the varying demands within the body at different developmental stages.

Dissecting Innate and Adaptive Immunity in Inflammatory Bowel Disease: Immune Compartmentalization, Microbiota Crosstalk, and Emerging Therapies

The intestinal immune system is the largest immune organ in the human body. Excessive immune response to intestinal cavity induced by harmful stimuli including pathogens, foreign substances and food antigens is an important cause of inflammatory diseases such as celiac disease and inflammatory bowel disease (IBD). Although great progress has been made in the treatment of IBD by some immune-related biotherapeutic products, yet a considerable proportion of IBD patients remain unresponsive or immune tolerant to immunotherapeutic strategy. Therefore, it is necessary to further understand the mechanism of immune cell populations involved in enteritis, including dendritic cells, macrophages and natural lymphocytes, in the steady-state immune tolerance of IBD, in order to find effective IBD therapy. In this review, we discussed the important role of innate and adaptive immunity in the development of IBD. And the relationship between intestinal immune system disorders and microflora crosstalk were also presented. We also focus on the new findings in the field of T cell immunity, which might identify novel cytokines, chemokines or anti-cytokine antibodies as new approaches for the treatment of IBD.

Overview of the development, characterization, and function of human types 1, 2, and 3 innate lymphoid cells

Hematopoiesis is characterized by the differentiation and maturation of multipotent stem cells into hematopoietic cells. Common lymphoid progenitor cells differentiate into B and T lymphocytes; natural killer cells can also originate from common lymphoid progenitors. In recent years, a cellular subtype of lymphocytes, called innate lymphocytes, has been described. Innate lymphoid cells (ILCs) play an important effector and regulatory role in innate immunity, and similar to natural killer cells, depend on the γc and Id2 chains for their development. These cells are divided into three main subtypes according to their characteristics, namely type 1 innate lymphocytes (ILC1), type 2 (ILC2), and type 3 (ILC3); the production of cytokines and transcription factors is essential for this classification. Furthermore, these cells have high plasticity, which allows them to change their phenotype in response to the environment. ILCs have recently been characterized further and emerged as a family of effectors and regulators of innate immune responses. Uncontrolled activation of these cells can contribute to inflammatory, autoimmune diseases and cancer. The current review aimed to describe their main characteristics, immunophenotypes, and plasticity, and based on the existing literature, suggested a phenotypic analysis to differentiate innate lymphocytes from natural killer cells, and across the subsets.

CD38 modulates cytokine secretion by NK cells through the Sirt1/NF-κB pathway, suppressing immune surveillance in colorectal cancer

Tregs and M2-type macrophages are essential for immune surveillance. CD38 + NK cells are involved in immunoregulation by modulating cytokine secretion. This study investigated how CD38 + NKs affect Tregs and macrophages in colorectal cancer (CRC). Higher proportions of CD38 + NKs and Tregs were detected in bloods and tumor tissues of CRC patients than that in the samples from healthy controls (HCs). Compared with CD38 + NKs from HCs, the NK cells from CRC promoted the differentiation of Tregs from CD4 + T cells, and secreted increased levels of IL-10, TGF-β and TNF-α and decreased levels of IFN-γ. CD38 + NKs from CRC expressed higher levels of CD38, NF-κB and acetyl-NF-κB and lower levels of Sirt1. When CRC CD38 + NK cells were treated with anti-CD38 monoclonal antibody, the above trends were reversed. CRC CD38 + NKs with treatment of NF-κB inhibitor also showed opposite effects on cytokine secretion and CD4 + T-cell differentiation. After treatment with a Sirt1 activator, NF-κB signaling was inhibited in these CD38 + NKs, whereas treatment with a Sirt1 inhibitor activated NF-κB signaling. The supernatants of CRC CD38 + NK culture promoted M0 macrophage polarization to M2-type. We suggest that CD38 modulates cytokine secretion by NK cells through Sirt1/NF-κB signaling pathway, thereby suppressing immune surveillance in tumorigenesis.

Direct activation of toll-like receptor 4 signaling in group 2 innate lymphoid cells contributes to inflammatory responses of allergic diseases

Group 2 innate lymphoid cells (ILC2s) are key players in type 2 immunity, but whether they can be directly activated by microbial ligands remain uncertain. In this study, we observed a positive correlation between blood endotoxin (LPS) levels and circulating ILC2s in allergic patients. In vitro, LPS robustly induced ILC2 proliferation and production of type 2 effector cytokines. RNA-seq revealed a type 2 immune-responsive profile in LPS-stimulated ILC2s. Notably, ILC2s lost their LPS-mediated growth and activation capacity when treated with TLR4 receptor antagonists and inhibitors of the NF-κB and JAK pathways, though this effect was not observed with IL-33 receptor blocking antibodies. Genetically, ILC2s from TLR4 knockout (KO) mice, but not from ST2 KO mice, were unresponsive to LPS. Collectively, these findings suggest a direct, non-canonical activation mechanism of ILC2s via the LPS-TLR4-NF-κB/JAK signaling axis.

Oral exposure to high concentrations of polystyrene microplastics alters the intestinal environment and metabolic outcomes in mice

Introduction

Oral exposure to microplastics (MPs) is a global health concern. In our previous study, MPs induced glucose intolerance and non-alcoholic fatty liver disease (NAFLD) under a high-fat diet-induced leaky gut syndrome (LGS). This study aims to evaluate the effects of high concentrations of MP on lipid metabolism under normal dietary conditions and to assess the changes in the intestinal tract resulting from MP exposure.

Methods

C57BL6/J mice were fed a normal diet (ND) without polystyrene MPs (PS-MPs) or with PS-MPs (1000 µg/L or 5000 µg/L) for six weeks. Subsequently, intestinal permeability, gut microbiota, and metabolite levels in the serum, feces, and liver were determined.

Results

Mice fed the ND showed no increase in intestinal permeability in either group. However, high MPs concentrations led to increased serum lipid levels and exacerbated fatty liver function. Oral exposure to MPs did not affect the number of innate lymphoid cells or short-chain fatty acids in the intestine. However, it increased the number of natural killer cells, altered the gut microbiota, induced inflammation, and modulated the expression of genes related to nutrient transport in the intestine. The severity of intestinal disturbance tended to worsen with dose.

Discussion

Despite the absence of LGS, high concentrations of MPs induced dyslipidemia and NAFLD. Oral exposure to MPs triggered intestinal inflammation via natural killer cells, altered the gut microbiota, and modulated nutrient metabolism. Our study highlights the need for environmental measures to reduce oral MPs exposure in the future.

CTLA-4 expressing innate lymphoid cells modulate mucosal homeostasis in a microbiota dependent manner

The maintenance of intestinal homeostasis is a fundamental process critical for organismal integrity. Sitting at the interface of the gut microbiome and mucosal immunity, adaptive and innate lymphoid populations regulate the balance between commensal micro-organisms and pathogens. Checkpoint inhibitors, particularly those targeting the CTLA-4 pathway, disrupt this fine balance and can lead to inflammatory bowel disease and immune checkpoint colitis. Here, we show that CTLA-4 is expressed by innate lymphoid cells and that its expression is regulated by ILC subset-specific cytokine cues in a microbiota-dependent manner. Genetic deletion or antibody blockade of CTLA-4 in multiple in vivo models of colitis demonstrates that this pathway plays a key role in intestinal homeostasis. Lastly, we have found that this observation is conserved in human IBD. We propose that this population of CTLA-4-positive ILC may serve as an important target for the treatment of idiopathic and iatrogenic intestinal inflammation.

The Role of Breastfeeding in Acute Respiratory Infections in Infancy

BACKGROUND

Acute respiratory infections (ARIs) affect the respiratory tract, are often caused by viruses such as respiratory syncytial virus and rhinovirus, and present symptoms such as coughing, fever, respiratory distress, and breathing difficulty. The global adherence to exclusive breastfeeding (BF) for the first 6 months of life has reached 44%, supported by the World Health Organization and United Nations International Children's Emergency Fund efforts. BF provides vital nutrients and contributes to infant immune system development, protecting against infections. The role of BF in preventing and reducing complications of ARIs in infants is gaining attention, prompting a review of current data and future research needs. This review aims to summarize the evidence on the role of BF in reducing the risk and severity of ARIs in infants, elucidate the adaptations in breast milk composition during infections, and identify relevant research needs.

METHODS AND RESULTS

Human milk (HM) is rich in immunoglobulins, antimicrobial peptides, and immunomodulatory factors that protect against various pathogens, including respiratory viruses. Several studies have demonstrated that BF is associated with a significant reduction in hospitalization, oxygen requirements, and mortality in infants with ARIs. The effectiveness of BF varies according to the specific respiratory virus, and a longer duration of exclusive BF appears to enhance its protective effect. It is documented that the composition of HM adjusts dynamically in response to infections, fortifying the infant's immune defenses. Specific immunological components of HM, including leukocytes and immunoglobulins, increase in response to infection in the infant, contributing to the enhancement of the immune defense in infants. Immune-boosting microRNAs enhance immune transfer to the infants and promote early gut maturation, and the HM microbiome along with other factors modifies the infant's gut microbiome and immune system.

CONCLUSIONS

BF defends infants from respiratory infections, and the investigation of the microRNAs in HM offers new insights into its antiviral properties. The promotion of BF, especially in vulnerable communities, is of paramount importance in alleviating the global burden of ARIs in infancy.

Bimin Kang ameliorates the minimal persistent inflammation in allergic rhinitis by reducing BCL11B expression and regulating ILC2 plasticity

ETHNOPHARMACOLOGICAL RELEVANCE

Minimal persistent inflammation (MPI) is a major contributor to the recurrence of allergic rhinitis (AR). The traditional Chinese herbal medicine known as Bimin Kang Mixture (BMK) have been used in clinics for decades to treat AR, which can relieve AR symptoms, reduce inflammatory response and improve immune function. However, its mechanism in controlling MPI is still unclear.

AIM OF THE STUDY

This study aims to assess the therapeutic effect of BMK on MPI, and elaborate the mechanism involved in BMK intervention in BCL11B regulation of type 2 innate lymphoid cell (ILC2) plasticity in the treatment of MPI.

MATERIAL AND METHODS

The effect of BMK (9.1 ml/kg) and Loratadine (15.15 mg/kg) on MPI was evaluated based on symptoms, pathological staining, and ELISA assays. RT-qPCR and flow cytometry were also employed to assess the expression of BCL11B, IL-12/IL-12Rβ2, and IL-18/IL-18Rα signaling pathways associated with ILC2 plasticity in the airway tissues of MPI mice following BMK intervention.

RESULTS

BMK restored the airway epithelial barrier, and markedly reduced inflammatory cells (eosinophils, neutrophils) infiltration (P < 0.01) and goblet cells hyperplasia (P < 0.05). BCL11B expression positively correlated with the ILC2 proportion in the lungs and nasal mucosa of AR and MPI mice (P < 0.01). BMK downregulated BCL11B expression (P < 0.05) and reduced the proportion of ILC2, ILC3 and ILC3-like ILC2 subsets (P < 0.05). Moreover, BMK promoted the conversion of ILC2 into an ILC1-like phenotype through IL-12/IL-12Rβ2 and IL-18/IL-18Rα signaling pathways in MPI mice.

CONCLUSION

By downregulating BCL11B expression, BMK regulates ILC2 plasticity and decreases the proportion of ILC2, ILC3, and ILC3-like ILC2 subsets, promoting the conversion of ILC2 to ILC1, thus restoring balance of ILC subsets in airway tissues and control MPI.

(Multi-) omics studies of ILC2s in inflammation and metabolic diseases

Type 2 innate lymphoid cells (ILC2s) have emerged as pivotal regulators in the pathogenesis of diseases, with their roles in inflammation, metabolism, and tissue homeostasis becoming increasingly recognized. This review provides an overview of the current understanding of ILC2s in inflammation and metabolic disorders, including their functional contributions. Moreover, we will discuss how these cells adapt their metabolic processes to support their function and survival and how their metabolic requirements change under different physiological and pathological conditions. Lastly, we will review recent omics studies that have provided insights into the molecular and cellular characteristics of ILC2s. This includes transcriptomic, proteomic, and metabolomic analyses that have elucidated the gene expression profiles, protein interactions, and metabolic networks, respectively, associated with ILC2s. These studies have advanced our understanding of the functional diversity of ILC2s and their involvement in metabolic disease.