Functional interactions between innate lymphoid cells and adaptive immunity

Circulating subpopulations of non-cytotoxic ILCs in diffuse large B-cell lymphoma

Non-cytotoxic innate lymphoid cells (ILCs) have been added to the list of immune cells that may contribute to the tumor microenvironment. Elevated levels of total ILCs and their subgroups have been reported in peripheral blood and tissue samples from patients with solid tumors, but their frequency in non-Hodgkin lymphomas, particularly diffuse large B-cell lymphoma (DLBCL), has not been clearly established. This study examined frequency and subset distribution in newly diagnosed DLBCL patients (nodal and extra-nodal) and compared it with blood specimens from healthy donors. The percentage of total ILCs (Lin - CD127+) was assessed by flow cytometry, as well as the four ILC subsets, defined as ILC1 (Lin - CD127 + cKit - CRTH2-), ILC2 (Lin - CD127 + cKit+/- CRTH2+), ILCp NCR- (Lin - CD127 + cKit + CRTH2- NKp46-) and NCR + ILC3 (Lin - CD127 + cKit + NKp46+). In the studied group of patients (n = 54), significantly lower levels of circulating total ILCs, ILC1, and ILCp NCR- were observed compared to the control group (n = 43). Similarly, there was a statistically significant decrease in the median frequency of NKp46 + ILC3 cells in lymphoma patients. Analysis of the ILC2 subpopulation showed no significant differences. The correlation of the distribution of individual subpopulations of ILCs with the stage and location of the tumor was also demonstrated. Our results suggest that circulating ILCs are activated and differentiated and/or differentially recruited to the lymph nodes or tumor microenvironment where they may be involved in antitumor defense. However, our observations require confirmation in functional studies.

Intestinal CXCR6+ ILC3s migrate to the kidney and exacerbate renal fibrosis via IL-23 receptor signaling enhanced by PD-1 expression

Group 3 innate lymphoid cells (ILC3s) regulate inflammation and tissue repair at mucosal sites, but whether these functions pertain to other tissues-like the kidneys-remains unclear. Here, we observed that renal fibrosis in humans was associated with increased ILC3s in the kidneys and blood. In mice, we showed that CXCR6+ ILC3s rapidly migrated from the intestinal mucosa and accumulated in the kidney via CXCL16 released from the injured tubules. Within the fibrotic kidney, ILC3s increased the expression of programmed cell death-1 (PD-1) and subsequent IL-17A production to directly activate myofibroblasts and fibrotic niche formation. ILC3 expression of PD-1 inhibited IL-23R endocytosis and consequently amplified the JAK2/STAT3/RORγt/IL-17A pathway that was essential for the pro-fibrogenic effect of ILC3s. Thus, we reveal a hitherto unrecognized migration pathway of ILC3s from the intestine to the kidney and the PD-1-dependent function of ILC3s in promoting renal fibrosis.

Implications of innate lymphoid cells in oral diseases

Innate lymphoid cells (ILCs), as newly discovered antigen-independent innate immune cells, respond promptly to stimuli by secreting effector cytokines to exert effector functions similar to those of T cells. ILCs predominantly reside at mucosal sites and play critical roles in defending against infections, maintaining mucosal homeostasis, regulating inflammatory and immune responses, and participating in tumorigenesis. Recently, there has been a growing interest in the role of ILCs in oral diseases. This review outlines the classifications and the major characteristics of ILCs, and then comprehensively expatiates the research on ILCs in oral cancer, primary Sjogren's syndrome, periodontal diseases, oral lichen planus, oral candidiasis, Behcet's disease, and pemphigus vulgaris, aiming at summarising the implications of ILCs in oral diseases and providing new ideas for further research.

p53 suppresses the inflammatory response following respiratory syncytial virus infection by inhibiting TLR2

-Respiratory syncytial virus (RSV) is a pivotal virus leading to acute lower respiratory tract infections in children under 5 years old. This study aimed to explore the correlation between p53 and Toll-like receptors (TLRs) post RSV infection. p53 levels exhibited a substantial decrease in nasopharyngeal aspirates (NPAs) from infants with RSV infection compared to control group. Manipulating p53 expression had no significant impact on RSV replication or interferon signaling pathway. Suppression of p53 expression led to heightened inflammation following RSV infection in A549 cells or airways of BALB/c mice. while stabilizing p53 expression using Nutlin-3a mitigated the inflammatory response in A549 cells. Additionally, Inhibiting p53 expression significantly increased Toll-like receptor 2 (TLR2) expression in RSV-infected epithelial cells and BALB/c mice. Furthermore, the TLR2 inhibitor, C29, effectively reduced inflammation mediated by p53 in A549 cells. Collectively, our results indicate that p53 modulates the inflammatory response after RSV infection through TLR2.

Immune consequences of exercise in hypoxia: A narrative review

Immune outcomes are key mediators of many health benefits of exercise and are determined by exercise type, dose (frequency/duration, intensity), and individual characteristics. Similarly, reduced availability of ambient oxygen (hypoxia) modulates immune functions depending on the hypoxic dose and the individual capacity to respond to hypoxia. How combined exercise and hypoxia (e.g., high-altitude training) sculpts immune responses is not well understood, although such combinations are becoming increasingly popular. Therefore, in this paper, we summarize the impact on immune responses of exercise and of hypoxia, both independently and together, with a focus on specialized cells in the innate and adaptive immune system. We review the regulation of the immune system by tissue oxygen levels and the overlapping and distinct immune responses related to exercise and hypoxia, then we discuss how they may be modulated by nutritional strategies. Mitochondrial, antioxidant, and anti-inflammatory mechanisms underlie many of the adaptations that can lead to improved cellular metabolism, resilience, and overall immune functions by regulating the survival, differentiation, activation, and migration of immune cells. This review shows that exercise and hypoxia can impair or complement/synergize with each other while regulating immune system functions. Appropriate acclimatization, training, and nutritional strategies can be used to avoid risks and tap into the synergistic potentials of the poorly studied immune consequences of exercising in a hypoxic state.

Immune mechanisms in the pathophysiology of hypertension

Hypertension is a leading risk factor for morbidity and mortality worldwide. Despite current anti-hypertensive therapies, most individuals with hypertension fail to achieve adequate blood pressure control. Moreover, even with adequate control, a residual risk of cardiovascular events and associated organ damage remains. These findings suggest that current treatment modalities are not addressing a key element of the underlying pathology. Emerging evidence implicates immune cells as key mediators in the development and progression of hypertension. In this Review, we discuss our current understanding of the diverse roles of innate and adaptive immune cells in hypertension, highlighting key findings from human and rodent studies. We explore mechanisms by which these immune cells promote hypertensive pathophysiology, shedding light on their multifaceted involvement. In addition, we highlight advances in our understanding of autoimmunity, HIV and immune checkpoints that provide valuable insight into mechanisms of chronic and dysregulated inflammation in hypertension.

Immunological aspects of central neurodegeneration

The etiology of various neurodegenerative disorders that mainly affect the central nervous system including (but not limited to) Alzheimer's disease, Parkinson's disease and Huntington's disease has classically been attributed to neuronal defects that culminate with the loss of specific neuronal populations. However, accumulating evidence suggests that numerous immune effector cells and the products thereof (including cytokines and other soluble mediators) have a major impact on the pathogenesis and/or severity of these and other neurodegenerative syndromes. These observations not only add to our understanding of neurodegenerative conditions but also imply that (at least in some cases) therapeutic strategies targeting immune cells or their products may mediate clinically relevant neuroprotective effects. Here, we critically discuss immunological mechanisms of central neurodegeneration and propose potential strategies to correct neurodegeneration-associated immunological dysfunction with therapeutic purposes.

Dysregulation of Wnt/β-catenin signaling contributes to intestinal inflammation through regulation of group 3 innate lymphoid cells

RORγt+ group 3 innate lymphoid cells (ILC3s) are essential for intestinal homeostasis. Dysregulation of ILC3s has been found in the gut of patients with inflammatory bowel disease and colorectal cancer, yet the specific mechanisms still require more investigation. Here we observe increased β-catenin in intestinal ILC3s from inflammatory bowel disease and colon cancer patients compared with healthy donors. In contrast to promoting RORγt expression in T cells, activation of Wnt/β-catenin signaling in ILC3s suppresses RORγt expression, inhibits its proliferation and function, and leads to a deficiency of ILC3s and subsequent intestinal inflammation in mice. Activated β-catenin and its interacting transcription factor, TCF-1, cannot directly suppress RORγt expression, but rather alters global chromatin accessibility and inhibits JunB expression, which is essential for RORγt expression in ILC3s. Together, our findings suggest that dysregulated Wnt/β-catenin signaling impairs intestinal ILC3s through TCF-1/JunB/RORγt regulation, further disrupting intestinal homeostasis, and promoting inflammation and cancer.

Gut microbiota and acute kidney injury: immunological crosstalk link

The gut microbiota, often called the "forgotten organ," plays a crucial role in bidirectional communication with the host for optimal physiological function. This communication helps regulate the host's immunity and metabolism positively and negatively. Many factors influence microbiota homeostasis and subsequently lead to an immune system imbalance. The correlation between an unbalanced immune system and acute diseases such as acute kidney injury is not fully understood, and the role of gut microbiota in disease pathogenesis is still yet uncovered. This review summarizes our understanding of gut microbiota, focusing on the interactions between the host's immune system and the microbiome and their impact on acute kidney injury.

The immune system in neurological diseases: What innate-like T cells have to say

The immune system classically consists of 2 lines of defense, innate and adaptive, both of which interact with one another effectively to protect us against any pathogenic threats. Importantly, there is a diverse subset of cells known as innate-like T cells that act as a bridge between the innate and adaptive immune systems and are pivotal players in eliciting inflammatory immune responses. A growing body of evidence has demonstrated the regulatory impact of these innate-like T cells in central nervous system (CNS) diseases and that such immune cells can traffic into the brain in multiple pathological conditions, which can be typically attributed to the breakdown of the blood-brain barrier. However, until now, it has been poorly understood whether innate-like T cells have direct protective or causative properties, particularly in CNS diseases. Therefore, in this review, our attention is focused on discussing the critical roles of 3 unique subsets of unconventional T cells, namely, natural killer T cells, γδ T cells, and mucosal-associated invariant T cells, in the context of CNS diseases, disorders, and injuries and how the interplay of these immune cells modulates CNS pathology, in an attempt to gain a better understanding of their complex functions.

SARS-CoV-2: A Glance at the Innate Immune Response Elicited by Infection and Vaccination

The COVID-19 pandemic caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has led to almost seven million deaths worldwide. SARS-CoV-2 causes infection through respiratory transmission and can occur either without any symptoms or with clinical manifestations which can be mild, severe or, in some cases, even fatal. Innate immunity provides the initial defense against the virus by sensing pathogen-associated molecular patterns and triggering signaling pathways that activate the antiviral and inflammatory responses, which limit viral replication and help the identification and removal of infected cells. However, temporally dysregulated and excessive activation of the innate immune response is deleterious for the host and associates with severe COVID-19. In addition to its defensive role, innate immunity is pivotal in priming the adaptive immune response and polarizing its effector function. This capacity is relevant in the context of both SARS-CoV-2 natural infection and COVID-19 vaccination. Here, we provide an overview of the current knowledge of the innate immune responses to SARS-CoV-2 infection and vaccination.

Role of Formyl Peptide Receptors and β-Arrestin-1 in suPAR Signal Transduction in Mouse Podocytes: Interactions with αVβ3-Integrin

The soluble urokinase plasminogen activator receptor (suPAR) has been implicated in a wide range of pathological conditions including primary nephrotic syndromes and acute kidney injuries. suPAR can trigger transduction cascades in podocytes by outside-in activation of αVβ3-integrin, but there is evidence that the functional cell surface response element is actually a complex of different types of receptors, which may also include the receptor for advanced glycation end-products (RAGE) and formyl peptide receptors (FPRs). Here we observed that ROS accumulation and Src activation could be evoked by continuous 24 h exposure to either suPAR or the FPR agonist fMLF. Responses to suPAR and fMLF were completely blocked by either the FPR antagonist WRW4 or by the αV-integrin inhibitor cilengitide. Moreover, endogenous podocyte mouse Fpr1 co-immunoprecipitates with β3-integrin, suggesting that these receptors occur as a complex on the cell surface. suPAR- and fMLF-evoked activation of Src and ROS differed in time course. Thus, robust pertussis toxin (PTX)-sensitive responses were evoked by 60 min exposures to fMLF but not to suPAR. By contrast, responses to 24 h exposures to either suPAR or fMLF were PTX-resistant and were instead abolished by knockdown of β-arrestin-1 (BAR1). FPRs, integrins, and RAGE (along with various Toll-like receptors) can all function as pattern-recognition receptors that respond to "danger signals" associated with infections and tissue injury. The fact that podocytes express such a wide array of pattern-recognition receptors suggests that the glomerular filter is designed to change its function under certain conditions, possibly to facilitate clearance of toxic macromolecules.

Natural killer cells and innate lymphoid cells but not NKT cells are mature in their cytokine production at birth

Early life is a time of increased susceptibility to infectious diseases and development of allergy. Innate lymphocytes are crucial components of the initiation and regulation of immune responses at mucosal surfaces, but functional differences in innate lymphocytes early in life are not fully described. We aimed to characterize the abundance and function of different innate lymphocyte cell populations in cord blood in comparison to that of adults. Blood was collected from adult donors and umbilical vessels at birth. Multicolor flow cytometry panels were used to identify and characterize lymphocyte populations and their capacity to produce hallmark cytokines. Lymphocytes were more abundant in cord blood compared to adults, however, mucosal-associated invariant T cells and natural killer T (NKT)-like cells, were far less abundant. The capacity of NKT-like cells to produce cytokines and their expression of the cytotoxic granule protein granzyme B and the marker of terminal differentiation CD57 were much lower in cord blood than in adults. In contrast, natural killer (NK) cells were as abundant in cord blood as in adults, they could produce IFNγ, and their expression of granzyme B was not significantly different from that of adult NK cells, although CD57 expression was lower. All innate lymphoid cell (ILC) subsets were more abundant in cord blood, and ILC1 and ILC2 were capable of production of IFNγ and IL-13, respectively. In conclusion, different innate lymphoid cells differ in both abundance and function in peripheral blood at birth and with important implications for immunity in early life.

Cell Death Pathway Regulation by Functional Nanomedicines for Robust Antitumor Immunity

Cancer immunotherapy has become a mainstream cancer treatment over traditional therapeutic modes. Cancer cells can undergo programmed cell death including ferroptosis, pyroptosis, autophagy, necroptosis, apoptosis and cuproptosis which are find to have intrinsic relationships with host antitumor immune response. However, direct use of cell death inducers or regulators may bring about severe side effects that can also be rapidly excreted and degraded with low therapeutic efficacy. Nanomaterials are able to carry them for long circulation time, high tumor accumulation and controlled release to achieve satisfactory therapeutic effect. Nowadays, a large number of studies have focused on nanomedicines-based strategies through modulating cell death modalities to potentiate antitumor immunity. Herein, immune cell types and their function are first summarized, and state-of-the-art research progresses in nanomedicines mediated cell death pathways (e.g., ferroptosis, pyroptosis, autophagy, necroptosis, apoptosis and cuproptosis) with immune response provocation are highlighted. Subsequently, the conclusion and outlook of potential research focus are discussed.

Washed microbiota transplantation promotes homing of group 3 innate lymphoid cells to the liver via the CXCL16/CXCR6 axis: a potential treatment for metabolic-associated fatty liver disease

Despite the observed decrease in liver fat associated with metabolic-associated fatty liver disease (MAFLD) in mice following fecal microbiota transplantation, the clinical effects and underlying mechanisms of washed microbiota transplantation (WMT), a refined method of fecal microbiota transplantation, for the treatment of MAFLD remain unclear. In this study, both patients and mice with MAFLD exhibit an altered gut microbiota composition. WMT increases the levels of beneficial bacteria, decreases the abundance of pathogenic bacteria, and reduces hepatic steatosis in MAFLD-affected patients and mice. Downregulation of the liver-homing chemokine receptor CXCR6 on ILC3s results in an atypical distribution of ILC3s in patients and mice with MAFLD, characterized by a significant reduction in ILC3s in the liver and an increase in ILC3s outside the liver. Moreover, disease severity is negatively correlated with the proportion of hepatic ILC3s. These hepatic ILC3s demonstrate a mitigating effect on hepatic steatosis through the release of IL-22. Mechanistically, WMT upregulates CXCR6 expression on ILC3s, thereby facilitating their migration to the liver of MAFLD mice via the CXCL16/CXCR6 axis, ultimately contributing to the amelioration of MAFLD. Overall, these findings highlight that WMT and targeting of liver-homing ILC3s could be promising strategies for the treatment of MAFLD.

Bcl6 is a subset-defining transcription factor of lymphoid tissue inducer-like ILC3

Innate lymphoid cells (ILCs) are tissue-resident effector cells with roles in tissue homeostasis, protective immunity, and inflammatory disease. Group 3 ILCs (ILC3s) are classically defined by the master transcription factor RORγt. However, ILC3 can be further subdivided into subsets that share type 3 effector modules that exhibit significant ontological, transcriptional, phenotypic, and functional heterogeneity. Notably lymphoid tissue inducer (LTi)-like ILC3s mediate effector functions not typically associated with other RORγt-expressing lymphocytes, suggesting that additional transcription factors contribute to dictate ILC3 subset phenotypes. Here, we identify Bcl6 as a subset-defining transcription factor of LTi-like ILC3s in mice and humans. Deletion of Bcl6 results in dysregulation of the LTi-like ILC3 transcriptional program and markedly enhances expression of interleukin-17A (IL-17A) and IL-17F in LTi-like ILC3s in a manner in part dependent upon the commensal microbiota-and associated with worsened inflammation in a model of colitis. Together, these findings redefine our understanding of ILC3 subset biology.

Microbiota as key factors in inflammatory bowel disease

Inflammatory Bowel Disease (IBD) is characterized by prolonged inflammation of the gastrointestinal tract, which is thought to occur due to dysregulation of the immune system allowing the host's cells to attack the GI tract and cause chronic inflammation. IBD can be caused by numerous factors such as genetics, gut microbiota, and environmental influences. In recent years, emphasis on commensal bacteria as a critical player in IBD has been at the forefront of new research. Each individual harbors a unique bacterial community that is influenced by diet, environment, and sanitary conditions. Importantly, it has been shown that there is a complex relationship among the microbiome, activation of the immune system, and autoimmune disorders. Studies have shown that not only does the microbiome possess pathogenic roles in the progression of IBD, but it can also play a protective role in mediating tissue damage. Therefore, to improve current IBD treatments, understanding not only the role of harmful bacteria but also the beneficial bacteria could lead to attractive new drug targets. Due to the considerable diversity of the microbiome, it has been challenging to characterize how particular microorganisms interact with the host and other microbiota. Fortunately, with the emergence of next-generation sequencing and the increased prevalence of germ-free animal models there has been significant advancement in microbiome studies. By utilizing human IBD studies and IBD mouse models focused on intraepithelial lymphocytes and innate lymphoid cells, this review will explore the multifaceted roles the microbiota plays in influencing the immune system in IBD.

What do we know about co-stimulatory and co-inhibitory immune checkpoint signals in ankylosing spondylitis?

Ankylosing spondylitis is the main entity of a family of inflammatory diseases affecting many musculoskeletal (sacroiliac joints, spine, and peripheral joints) and extra-musculoskeletal sites, termed spondyloarthritis. While it is debated whether disease onset is primarily driven by autoimmune or autoinflammatory processes, what is certain is that both innate and adaptive immune responses orchestrate local and systemic inflammation, which leads to chronic pain and immobility. Immune checkpoint signals are one key player in keeping the immune system in check and in balance, but their role in disease pathogenesis is still rather elusive. Therefore, we ran a MEDLINE search utilizing the PubMed platform for a variety of immune checkpoint signals in regard to ankylosing spondylitis. In this review, we summarize the experimental and genetic data available and evaluate the relevance of immune checkpoint signalling in the pathogenesis of ankylosing spondylitis. Markers such as PD-1 and CTLA-4 have been extensively studied and facilitate the concept of an impaired negative immune regulation in ankylosing spondylitis. Other markers are either neglected completely or insufficiently examined, and the data is conflicting. Still, some of those markers remain interesting targets to decipher the pathogenesis of ankylosing spondylitis and to develop new treatment strategies.

Distinct WBC Trajectories are Associated with the Risks of Incident CVD and All-Cause Mortality

AIMS

To examine the trajectory of white blood cell (WBC) and their potential impacts on cardiovascular disease (CVD) and all-cause mortality (ACM) risks.

METHODS

This prospective cohort included 61,666 participants without CVD on or before June 1, 2012. Latent mixture modeling was used to identify WBC trajectories in 2006-2012 as predictors of CVD and ACM. Incident CVD and ACM in 2012-2019 were the outcomes. Cox proportional hazards models were fitted to analyze the risks of incident CVD and ACM.

RESULTS

According to WBC ranges and dynamics, five distinct WBC trajectories were identified: low-stable (n=18,432), moderate-stable (n=26,656), elevated-stable (n=3,153), moderate-increasing (n=11,622), and elevated-decreasing (n=1,803). During 6.65±0.83 years of follow-up, we documented 3773 incident CVD cases and 3304 deaths. Relative to the low-stable pattern, the moderate-increasing pattern was predictive of an elevated risk of CVD (HR=1.36, 95% CI: 1.24-1.50), especially acute myocardial infarction (AMI) (HR=1.91, 95% CI: 1.46-2.51), while the elevated-stable pattern was predictive of an elevated risk of ACM (HR=1.77, 95% CI: 1.52-2.06). Among participants with hs-CRP ＜2 mg/L or ≥2 mg/L, similar associations were observed between the moderate-increasing pattern with CVD (HR=1.41, 95% CI: 1.24-1.61) and ACM (HR=1.54, 95% CI: 1.18-2.01, HR=1.89, 95% CI: 1.57-2.29, respectively).

CONCLUSIONS

We found that distinct WBC trajectories were differentially associated with CVD and ACM risks in Chinese adults.

Immune cells in pemphigus vulgaris and bullous Pemphigoid: From pathogenic roles to targeting therapies

Pemphigus vulgaris (PV) and bullous pemphigoid (BP) are two major subtypes of autoimmune bullous diseases (AIBD), characterized by blisters and erosions of skin and/or mucous membranes with dysregulated immune activity. Current literature established that T and B cells are the main executors of PV and BP. Emerging evidence revealed that macrophages and related cytokines also contribute to these diseases. While the role of lymphocytes on PV and BP is well established, the definitive functions of macrophages in disease progression are not fully understood. Furthermore, current status of clinical trials targeting immune cells is poorly recapitulated in PV and BP. In this review, we summarized current knowledge in this rapidly advancing field, with emphasis on the individual functions of immune cells and their interactions, as well as ongoing clinical trials targeting immune cells, to provide novel insights in mechanistic understanding and clinical management of PV and BP.

Bcl-2 supports survival and metabolic fitness of quiescent tissue-resident ILC3

Group 3 innate lymphoid cells (ILC3) are potent effector cells with critical roles in enforcing immunity, barrier integrity and tissue homeostasis along the gastrointestinal tract. ILC3 are considered primarily tissue-resident cells, seeding the gastrointestinal tract during embryonic stages and early life. However, the mechanisms through which mature ILC3 are maintained within adult tissues are poorly understood. Here, we report that lymphoid tissue-inducer-like (LTi-like) ILC3 exhibit minimal turnover in the healthy adult intestinal tract, persist for extended periods of time, and display a quiescent phenotype. Strikingly, during enteric bacterial infection LTi-like ILC3 also exhibit negligible hematopoietic replenishment and remain non-proliferative, despite robustly producing cytokines. Survival of LTi-like ILC3 was found to be dependent upon the balance between the metabolic activity required to drive effector function and anti-apoptotic programs. Notably, the pro-survival protein B-cell lymphoma-2 (Bcl-2) was required for the survival of LTi-like ILC3 ex vivo but was rendered partially dispensable if mitochondrial respiration was inhibited. Together we demonstrate LTi-like ILC3 are a tissue-resident, quiescent population that persist independently of hematopoietic replenishment to survive within the intestinal microenvironment.

Unveiling the mystery of ILC3s: Their functions and interactions in mucosal immunity

Innate lymphoid cells (ILCs) are a recently discovered subset of immune cells that play a crucial role in preserving tissue health and combating infections. Among these, ILC3s are particularly vital in regulating mucosal immunity across multiple organs such as the gut, lungs, and skin. The purpose of this article is to present a comprehensive and detailed overview of current knowledge on ILC3s, with a specific emphasis on their intricate interactions with various components of the intestinal microenvironment. Recent research on the complex, bidirectional communication pathways between ILC3s and intestinal epithelial cells, stromal cells, immune cells, microbiota, their metabolites, and diet are highlighted. Furthermore, this review comprehensively examines the diverse functions of ILC3s, which include lymphoid tissue development, tissue repair, infection, inflammation, and metabolic diseases, as well as the effector molecules that facilitate these functions. Overall, this review provides valuable insights into the biological and functional aspects of ILC3s and underscores their potential for developing innovative therapies for immune-mediated disorders, while also acknowledging the remaining knowledge gaps and challenges that need to be addressed.

Microbiota-dependent regulation of costimulatory and coinhibitory pathways via innate immune sensors and implications for immunotherapy

Our bodies are inhabited by trillions of microorganisms. The host immune system constantly interacts with the microbiota in barrier organs, including the intestines. Over decades, numerous studies have shown that our mucosal immune system is dynamically shaped by a variety of microbiota-derived signals. Elucidating the mediators of these interactions is an important step for understanding how the microbiota is linked to mucosal immune homeostasis and gut-associated diseases. Interestingly, the efficacy of cancer immunotherapies that manipulate costimulatory and coinhibitory pathways has been correlated with the gut microbiota. Moreover, adverse effects of these therapies in the gut are linked to dysregulation of the intestinal immune system. These findings suggest that costimulatory pathways in the immune system might serve as a bridge between the host immune system and the gut microbiota. Here, we review mechanisms by which commensal microorganisms signal immune cells and their potential impact on costimulation. We highlight how costimulatory pathways modulate the mucosal immune system through not only classical antigen-presenting cells but also innate lymphocytes, which are highly enriched in barrier organs. Finally, we discuss the adverse effects of immune checkpoint inhibitors in the gut and the possible relationship with the gut microbiota.

Group 2 innate lymphoid cells boost CD8+ T-cell activation in anti-tumor immune responses

Group 2 innate lymphoid cells (ILC2s) are essential for orchestrating type 2 immune responses during allergic airway inflammation and infection. ILC2s have been reported to play a regulatory role in tumors; however, this conclusion is controversial. In this study, we showed that IL-33-activated ILC2s could boost CD8+ T-cell function through direct antigen cross-presentation. After activation by IL-33, ILC2s showed an enhanced potential to process antigens and prime CD8+ T cell activation. Activated ILC2s could phagocytose exogenous antigens in vivo and in vitro, promoting antigen-specific CD8+ T cell function to enhance antitumor immune responses. Administration of OVA-loaded ILC2s induces robust antitumor effects on the OVA-expressing tumor model. These findings suggested that the administration of tumor antigen-loaded ILC2s might serve as a potential strategy for cancer treatment.

Modulation of innate lymphoid cells by enteric bacterial pathogens

Innate lymphoid cells (ILCs) are key regulators of tissue homeostasis, inflammation, and immunity to infections. ILCs rapidly respond to environmental cues such as cytokines, microbiota and invading pathogens which regulate their function and phenotype. Even though ILCs are rare cells, they are enriched at barrier surfaces such as the gastrointestinal (GI) tract, and they are often critical to the host's immune response to eliminate pathogens. On the other side of host-pathogen interactions, pathogenic bacteria also have the means to modulate these immune responses. Manipulation or evasion of the immune cells is often to the pathogen's benefit and/or to the detriment of competing microbiota. In some instances, specific bacterial virulence factors or toxins have been implicated in how the pathogen modulates immunity. In this review, we discuss the recent progress made towards understanding the role of non-cytotoxic ILCs during enteric bacterial infections, how these pathogens can modulate the immune response, and the implications these have on developing new therapies to combat infection.

Protective and pathogenic functions of innate lymphoid cells in transplantation

Innate lymphoid cells (ILCs) are a family of lymphocytes with essential roles in tissue homeostasis and immunity. Along with other tissue-resident immune populations, distinct subsets of ILCs have important roles in either promoting or inhibiting immune tolerance in a variety of contexts, including cancer and autoimmunity. In solid organ and hematopoietic stem cell transplantation, both donor and recipient-derived ILCs could contribute to immune tolerance or rejection, yet understanding of protective or pathogenic functions are only beginning to emerge. In addition to roles in directing or regulating immune responses, ILCs interface with parenchymal cells to support tissue homeostasis and even regeneration. Whether specific ILCs are tissue-protective or enhance ischemia reperfusion injury or fibrosis is of particular interest to the field of transplantation, beyond any roles in limiting or promoting allograft rejection or graft-versus host disease. Within this review, we discuss the current understanding of ILCs functions in promoting immune tolerance and tissue repair at homeostasis and in the context of transplantation and highlight where targeting or harnessing ILCs could have applications in novel transplant therapies.

Advances in tuft cells, a chemosensory cell in sequential diseases of the pancreas

Tuft cells are solitary chemosensory cells distributed mainly in hollow organs and detected in human and mouse pancreas precursor lesions of pancreatic cancer. Induced by inflammation and KRAS mutation, pancreatic acinar cell-derived tuft cells play a protective role in epithelium injury. The tumour suppression of tuft cells has been indicated in some studies. However, the function of tuft cells in pancreatic cancer remains unclear. In this review, we first introduce the definition of tuft cells and then review the relationship between tuft cells and pancreatic inflammation. In addition, we emphasized the role of tuft cells in the genesis and development of pancreatic cancers, especially the part of markers for tuft cell's doublecortin-like kinase 1 (DCLK1). Finally, we turn to the microscopic perspective and review the interactions between tuft cells and the microbiome in the pancreatic microenvironment. Overall, we describe the role of tuft cells in response to tissue damage and tumour progression in the pancreas. Nevertheless, the specific formation principle and the more detailed mechanism of action of tuft cells in the pancreas remain to be further explored.

Single-cell RNA sequencing of human lung innate lymphoid cells in the vascular and tissue niche reveals molecular features of tissue adaptation

Innate lymphoid cells (ILCs) are sentinels of healthy organ function, yet it is unknown how ILCs adapt to distinct anatomical niches within tissues. Here, we used a unique humanized mouse model, MISTRG mice transplanted with human hematopoietic stem and progenitor cells (HSPCs), to define the gene signatures of human ILCs in the vascular versus the tissue (extravascular) compartment of the lung. Single-cell RNA sequencing in combination with intravascular cell labeling demonstrated that heterogeneous populations of human ILCs and natural killer (NK) cells occupied the vascular and tissue niches in the lung of HSPC-engrafted MISTRG mice. Moreover, we discovered that niche-specific cues shape the molecular programs of human ILCs in the distinct sub-anatomical compartments of the lung. Specifically, extravasation of ILCs into the lung tissue was associated with the upregulation of genes involved in the acquisition of tissue residency, cell positioning within the lung, sensing of tissue-derived signals, cellular stress responses, nutrient uptake, and interaction with other tissue-resident immune cells. We also defined a core tissue signature shared between human ILCs and NK cells in the extravascular space of the lung, consistent with imprinting by signals from the local microenvironment. The molecular characterization of human ILCs and NK cells in the vascular and tissue niches of the lung provides new knowledge on the mechanisms of ILC tissue adaptation and represents a resource for further studies.

Mechanisms of lung damage in tuberculosis: implications for chronic obstructive pulmonary disease

Pulmonary tuberculosis is increasingly recognized as a risk factor for COPD. Severe lung function impairment has been reported in post-TB patients. Despite increasing evidence to support the association between TB and COPD, only a few studies describe the immunological basis of COPD among TB patients following successful treatment completion. In this review, we draw on well-elaborated Mycobacterium tuberculosis-induced immune mechanisms in the lungs to highlight shared mechanisms for COPD pathogenesis in the setting of tuberculosis disease. We further examine how such mechanisms could be exploited to guide COPD therapeutics.

Regulation of systemic metabolism by tissue-resident immune cell circuits

Recent studies have demonstrated that tissue homeostasis and metabolic function are dependent on distinct tissue-resident immune cells that form functional cell circuits with structural cells. Within these cell circuits, immune cells integrate cues from dietary contents and commensal microbes in addition to endocrine and neuronal signals present in the tissue microenvironment to regulate structural cell metabolism. These tissue-resident immune circuits can become dysregulated during inflammation and dietary overnutrition, contributing to metabolic diseases. Here, we review the evidence describing key cellular networks within and between the liver, gastrointestinal tract, and adipose tissue that control systemic metabolism and how these cell circuits become dysregulated during certain metabolic diseases. We also identify open questions in the field that have the potential to enhance our understanding of metabolic health and disease.

Reciprocal costimulatory molecules control the activation of mucosal type 3 innate lymphoid cells during engagement with B cells

Innate lymphoid cells (ILCs) are the counterpart of T helper cells in the innate immune system and share multiple phenotypes with T helper cells. Inducible T-cell costimulator (ICOS) is recognized on T cells and participates in T-cell activation and T and B-cell engagement in lymphoid tissues. However, the role of ICOS in ILC3s and ILC3-involved interactions with the immune microenvironment remains unclear. Here, we found that ICOS expression on human ILC3s was correlated with the activated state of ILC3s. ICOS costimulation enhanced the survival, proliferation, and capacity of ILC3s to produce cytokines (IL-22, IL-17A, IFN-γ, TNF, and GM-CSF). Via synergistic effects of ICOS and CD40 signaling, B cells promoted ILC3 functions, and ILC3-induced T-cell-independent B-cell IgA and IgM secretion primarily required CD40 signaling. Hence, ICOS is essential for the nonredundant role of ILC3s and their interaction with adjacent B cells.

Management of eosinophil-associated inflammatory diseases: the importance of a multidisciplinary approach

Elevated eosinophil counts in blood and tissue are a feature of many pathological processes. Eosinophils can migrate and accumulate in a wide variety of tissues and, by infiltrating a target organ, can mediate the development of several inflammatory diseases. The normalization of eosinophilia is a common biomarker of a treatable trait and can also be used as a prognostic and predictive biomarker since it implies a reduction in type 2 inflammation that contributes to disease pathogenesis. Biological therapies targeting this cell type and its proinflammatory mediators have been shown to be effective in the management of a number of eosinophilic diseases, and for this reason they constitute a potential common strategy in the treatment of patients with various multimorbidities that present with type 2 inflammation. Various biological options are available that could be used to simultaneously treat multiple target organs with a single drug, bearing in mind the need to offer personalized treatments under the umbrella of precision medicine in all patients with eosinophil-associated diseases (EADs). In addition to reviewing these issues, we also discuss a series of perspectives addressing the management of EAD patients from a multidisciplinary approach, with the collaboration of health professionals from different specialties who manage the different multimorbidities that frequently occur in these patients. We examine the basic principles of care that this multidisciplinary approach must cover and present a multidisciplinary expert opinion regarding the ideal management of patients with EADs, from diagnosis to therapeutic approach and follow-up.

Single-cell landscape dissecting the transcription and heterogeneity of innate lymphoid cells in ischemic heart

Background

Until now, few articles have revealed the potential roles of innate lymphoid cells (ILCs) in cardiovascular diseases. However, the infiltration of ILC subsets in ischemic myocardium, the roles of ILC subsets in myocardial infarction (MI) and myocardial ischemia-reperfusion injury (MIRI) and the related cellular and molecular mechanisms have not been described with a sufficient level of detail.

Method

In the current study, 8-week-old male C57BL/6J mice were divided into three groups: MI, MIRI and sham group. Single-cell sequencing technology was used to perform dimensionality reduction clustering of ILC to analyze the ILC subset landscape at a single-cell resolution, and finally flow cytometry was used to confirm the existence of the new ILC subsets in different disease groups.

Results

Five ILC subsets were found, including ILC1, ILC2a, ILC2b, ILCdc and ILCt. It is worth noting that ILCdc, ILC2b and ILCt were identified as new ILC subclusters in the heart. The cellular landscapes of ILCs were revealed and signal pathways were predicted. Furthermore, pseudotime trajectory analysis exhibited different ILC statuses and traced related gene expression in normal and ischemic conditions. In addition, we established a ligand-receptor-transcription factor-target gene regulatory network to disclose cell communications among ILC clusters. Moreover, we further revealed the transcriptional features of the ILCdc and ILC2a subsets. Finally, the existence of ILCdc was confirmed by flow cytometry.

Conclusion

Collectively, by characterizing the spectrums of ILC subclusters, our results provide a new blueprint for understanding ILC subclusters' roles in myocardial ischemia diseases and further potential treatment targets.

The Function of NK Cells in Tumor Metastasis and NK Cell-Based Immunotherapy

Metastatic tumors cause the most deaths in cancer patients. Treating metastasis remains the primary goal of current cancer research. Although the immune system prevents and kills the tumor cells, the function of the immune system in metastatic cancer has been unappreciated for decades because tumors are able to develop complex signaling pathways to suppress immune responses, leading them to escape detection and elimination. Studies showed NK cell-based therapies have many advantages and promise for fighting metastatic cancers. We here review the function of the immune system in tumor progression, specifically focusing on the ability of NK cells in antimetastasis, how metastatic tumors escape the NK cell attack, as well as the recent development of effective antimetastatic immunotherapies.

SARS-CoV-2: Immunity, Challenges with Current Vaccines, and a Novel Perspective on Mucosal Vaccines

The global rollout of COVID-19 vaccines has played a critical role in reducing pandemic spread, disease severity, hospitalizations, and deaths. However, the first-generation vaccines failed to block severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and transmission, partially due to the limited induction of mucosal immunity, leading to the continuous emergence of variants of concern (VOC) and breakthrough infections. To meet the challenges from VOC, limited durability, and lack of mucosal immune response of first-generation vaccines, novel approaches are being investigated. Herein, we have discussed the current knowledge pertaining to natural and vaccine-induced immunity, and the role of the mucosal immune response in controlling SARS-CoV2 infection. We have also presented the current status of the novel approaches aimed at eliciting both mucosal and systemic immunity. Finally, we have presented a novel adjuvant-free approach to elicit effective mucosal immunity against SARS-CoV-2, which lacks the safety concerns associated with live-attenuated vaccine platforms.

The Roles of Innate Lymphoid Cells in the Gastric Mucosal Immunology and Oncogenesis of Gastric Cancer

Innate lymphoid cells (ILCs) are a group of innate immune cells that have garnered considerable attention due to their critical roles in regulating immunity and tissue homeostasis. They are particularly abundant in the gastrointestinal tract, where they have been shown to interact with commensal bacteria, pathogens, and other components of the local microenvironment to influence host immune responses to infection and oncogenesis. Their tissue-residency properties enable gastric ILCs a localized and rapid response to alert and stress, which indicates their key potential in regulating immunosurveillance. In this review, we discuss the current understanding of the role of ILCs in the gastric mucosa, with a focus on their interactions with the gastric microbiota and Helicobacter pylori and their contributions to tissue homeostasis and inflammation. We also highlight recent findings on the involvement of ILCs in the pathogenesis of gastric cancer and the implications of targeting ILCs as a therapeutic approach. Overall, this review provides an overview of the diverse functions of ILCs in gastric mucosa and highlights their potential as targets for future therapies for gastric cancer.

Progress in nanoparticle-based regulation of immune cells

Immune cells are indispensable defenders of the human body, clearing exogenous pathogens and toxicities or endogenous malignant and aging cells. Immune cell dysfunction can cause an inability to recognize, react, and remove these hazards, resulting in cancers, inflammatory diseases, autoimmune diseases, and infections. Immune cells regulation has shown great promise in treating disease, and immune agonists are usually used to treat cancers and infections caused by immune suppression. In contrast, immunosuppressants are used to treat inflammatory and autoimmune diseases. However, the key to maintaining health is to restore balance to the immune system, as excessive activation or inhibition of immune cells is a common complication of immunotherapy. Nanoparticles are efficient drug delivery systems widely used to deliver small molecule inhibitors, nucleic acid, and proteins. Using nanoparticles for the targeted delivery of drugs to immune cells provides opportunities to regulate immune cell function. In this review, we summarize the current progress of nanoparticle-based strategies for regulating immune function and discuss the prospects of future nanoparticle design to improve immunotherapy.

The role of tumor-derived extracellular vesicles containing noncoding RNAs in mediating immune cell function and its implications from bench to bedside

Extracellular vesicles (EVs) are membrane-encapsulated vesicles released by almost all cell types, which participate in intercellular communication by delivering different types of molecular cargoes, such as non-coding RNAs (ncRNAs). Accumulating evidence suggests that tumor-derived EVs act as a bridge for intercellular crosstalk between tumor cells and surrounding cells, including immune cells. Tumor-derived EVs containing ncRNAs (TEV-ncRNAs) mediate intercellular crosstalk to manipulate immune responses and affect the malignant phenotypes of cancer cells. In this review, we summarize the double-edged roles and the underlying mechanisms of TEV-ncRNAs in regulating innate and adaptive immune cells. We also highlight the advantages of using TEV-ncRNAs in liquid biopsies for cancer diagnosis and prognosis. Moreover, we outline the use of engineered EVs to deliver ncRNAs and other therapeutic agents for cancer therapy.

Innate immune cellular therapeutics in transplantation

Successful organ transplantation provides an opportunity to extend the lives of patients with end-stage organ failure. Selectively suppressing the donor-specific alloimmune response, however, remains challenging without the continuous use of non-specific immunosuppressive medications, which have multiple adverse effects including elevated risks of infection, chronic kidney injury, cardiovascular disease, and cancer. Efforts to promote allograft tolerance have focused on manipulating the adaptive immune response, but long-term allograft survival rates remain disappointing. In recent years, the innate immune system has become an attractive therapeutic target for the prevention and treatment of transplant organ rejection. Indeed, contemporary studies demonstrate that innate immune cells participate in both the initial alloimmune response and chronic allograft rejection and undergo non-permanent functional reprogramming in a phenomenon termed "trained immunity." Several types of innate immune cells are currently under investigation as potential therapeutics in transplantation, including myeloid-derived suppressor cells, dendritic cells, regulatory macrophages, natural killer cells, and innate lymphoid cells. In this review, we discuss the features and functions of these cell types, with a focus on their role in the alloimmune response. We examine their potential application as therapeutics to prevent or treat allograft rejection, as well as challenges in their clinical translation and future directions for investigation.

Combination Therapy with Indigo and Indirubin for Ulcerative Colitis via Reinforcing Intestinal Barrier Function

Indigo and indirubin, the active molecules of traditional Chinese medicine indigo naturalis, exert therapeutic activity for ulcerative colitis (UC). Indigo and indirubin are isomers and have distinctive profiles in anti-inflammation, immune regulation, intestinal microbiota regulation, oxidative stress regulation, and intestinal mucosal repair for UC treatment. Thus, exploring its combined administration's integrated advantages for UC is critical. This study is aimed at clarifying the effect and mechanisms of the combined administration of indigo and indirubin on colitis mouse models. The results showed that all the treatment groups could improve the disease symptoms, and the combined administration showed the best effect. Additionally, compared with indigo and indirubin alone, the combination group could significantly reinforce intestinal barrier function by increasing the expression of E-cadherin, occludin, ZO-1, and MUC2 and improving intestinal permeability. The treatment groups significantly improved the expression of cytokines, including TNF-α, IFN-γ, IL-12, IL-23, and IL-17A, and indirubin presented the most potent anti-inflammatory effect. Furthermore, all the treatment groups reduced the infiltration of the immune cells in intestinal lamina propria and the production of ROS/RNS. Notably, indigo exhibited a more substantial capacity to regulate natural killer (NK) cells, ILC3, neutrophils, and dendritic cells, followed by the combination group and indirubin alone. Finally, all the treatment groups modulated intestinal microbiota composition, increased the proportion of beneficial microbiota, and decreased the proportion of microbiota. Our results indicated that indigo and indirubin synergistically reinforced the intestinal barrier function, which may be associated with integrating the indirubin anti-inflammatory and intestinal microbiota regulating strength and indigo immune and ROS/RNS regulation advantage.

Innate Lymphoid Cell Plasticity in Mucosal Infections

Mucosal tissue homeostasis is a dynamic process that involves multiple mechanisms including regulation of innate lymphoid cells (ILCs). ILCs are mostly tissue-resident cells which are critical for tissue homeostasis and immune response against pathogens. ILCs can sense environmental changes and rapidly respond by producing effector cytokines to limit pathogen spread and initiate tissue recovery. However, dysregulation of ILCs can also lead to immunopathology. Accumulating evidence suggests that ILCs are dynamic population that can change their phenotype and functions under rapidly changing tissue microenvironment. However, the significance of ILC plasticity in response to pathogens remains poorly understood. Therefore, in this review, we discuss recent advances in understanding the mechanisms regulating ILC plasticity in response to intestinal, respiratory and genital tract pathogens. Key transcription factors and lineage-guiding cytokines regulate this plasticity. Additionally, we discuss the emerging data on the role of tissue microenvironment, gut microbiota, and hypoxia in ILC plasticity in response to mucosal pathogens. The identification of new pathways and molecular mechanisms that control functions and plasticity of ILCs could uncover more specific and effective therapeutic targets for infectious and autoimmune diseases where ILCs become dysregulated.

MSI2 deficiency in ILC3s attenuates DSS-induced colitis by affecting the intestinal microbiota

Background

The etiology and pathogenesis of inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), are generally believed to be related to immune dysfunction and intestinal microbiota disorder. However, the exact mechanism is not yet fully understood. The pathological changes associated with dextran sodium sulfate (DSS)-induced colitis are similar to those in human UC. As a subgroup of the innate immune system, group 3 innate lymphoid cells (ILC3s) are widely distributed in the lamina propria of the intestinal mucosa, and their function can be regulated by a variety of molecules. Musashi2 (MSI2) is a type of evolutionarily conserved RNA-binding protein that maintains the function of various tissue stem cells and is essential for postintestinal epithelial regeneration. The effect of MSI2 deficiency in ILC3s on IBD has not been reported. Thus, mice with conditional MSI2 knockout in ILC3s were used to construct a DSS-induced colitis model and explore its effects on the pathogenesis of IBD and the species, quantity and function of the intestinal microbiota.

Methods

Msi2^flox/flox mice (Msi2^fl/fl ) and Msi2^flox/floxRorc^Cre mice (Msi2^ΔRorc ) were induced by DSS to establish the IBD model. The severity of colitis was evaluated by five measurements: body weight percentage, disease activity index, colon shortening degree, histopathological score and routine blood examination. The species, quantity and function of the intestinal microbiota were characterized by high-throughput 16S rRNA gene sequencing of DNA extracted from fecal samples.

Results

MSI2 was knocked out in the ILC3s of Msi2^ΔRorc mice. The Msi2^ΔRorc mice exhibited reductions in body weight loss, the disease activity index, degree of colon shortening, tissue histopathological score and immune cells in the peripheral blood compared to those of Msi2^fl/fl mice after DSS administration. The 16S rRNA sequencing results showed that the diversity of the intestinal microbiota in DSS-treated Msi2^ΔRorc mice changed, with the abundance of Firmicutes increasing and that of Bacteroidetes decreasing. The linear discriminant analysis effect size (LEfSe) approach revealed that Lactobacillaceae could be the key bacteria in the Msi2^ΔRorc mouse during the improvement of colitis. Using PICRUST2 to predict the function of the intestinal microbiota, it was found that the functions of differential bacteria inferred by modeling were mainly enriched in infectious diseases, immune system and metabolic functions.

Conclusions

MSI2 deficiency in ILC3s attenuated DSS-induced colonic inflammation in mice and affected intestinal microbiota diversity, composition, and function, with Lactobacillaceae belonging to the phylum Firmicutes possibly representing the key bacteria. This finding could contribute to our understanding of the pathogenesis of IBD and provide new insights for its clinical diagnosis and treatment.

The Polyamine Putrescine Is a Positive Regulator of Group 3 Innate Lymphocyte Activation

Group 3 innate lymphocytes (ILC3s) rapidly respond to invading pathogens or inflammatory signals, which requires shifting cellular metabolic demands. Metabolic adaptations regulating ILC3 function are not completely understood. Polyamines are polycationic metabolites that have diverse roles in cellular functions and in immunity regulate immune cell biology, including Th17 cells. Whether polyamines play a role in ILC3 activation is unknown. In this article, we report that the polyamine synthesis pathway is important for ILC3 activation. IL-23-activated mouse ILC3s upregulate ornithine decarboxylase, the enzyme catalyzing the rate-limiting step of the conversion of ornithine to putrescine in polyamine synthesis, with a subsequent increase in putrescine levels. Inhibition of ornithine decarboxylase via a specific inhibitor, α-difluoromethylornithine, reduced levels of IL-22 produced by steady-state or IL-23-activated ILC3s in a putrescine-dependent manner. Thus, the polyamine putrescine is a positive regulator of ILC3 activation. Our results suggest that polyamines represent a potential target for therapeutic modulation of ILC3 activation during infection or inflammatory disorders.

Mechanisms of gut microbiota-immune-host interaction on glucose regulation in type 2 diabetes

Intestinal absorption of food is one of the sources of glucose. Insulin resistance and impaired glucose tolerance caused by lifestyle and diet are the precursors of type 2 diabetes. Patients with type 2 diabetes have trouble controlling their blood sugar levels. For long-term health, strict glycemic management is necessary. Although it is thought to be well correlated with metabolic diseases like obesity, insulin resistance, and diabetes, its molecular mechanism is still not completely understood. Disturbed microbiota triggers the gut immune response to reshape the gut homeostasis. This interaction not only maintains the dynamic changes of intestinal flora, but also preserves the integrity of the intestinal barrier. Meanwhile, the microbiota establishes a systemic multiorgan dialog on the gut-brain and gut-liver axes, intestinal absorption of a high-fat diet affects the host's feeding preference and systemic metabolism. Intervention in the gut microbiota can combat the decreased glucose tolerance and insulin sensitivity linked to metabolic diseases both centrally and peripherally. Moreover, the pharmacokinetics of oral hypoglycemic medications are also influenced by gut microbiota. The accumulation of drugs in the gut microbiota not only affects the drug efficacy, but also changes the composition and function of them, thus may help to explain individual therapeutic variances in pharmacological efficacy. Regulating gut microbiota through healthy dietary patterns or supplementing pro/prebiotics can provide guidance for lifestyle interventions in people with poor glycemic control. Traditional Chinese medicine can also be used as complementary medicine to effectively regulate intestinal homeostasis. Intestinal microbiota is becoming a new target against metabolic diseases, so more evidence is needed to elucidate the intricate microbiota-immune-host relationship, and explore the therapeutic potential of targeting intestinal microbiota.

The role of group 3 innate lymphoid cell in intestinal disease

Group 3 innate lymphoid cells (ILC3s), a novel subpopulation of lymphocytes enriched in the intestinal mucosa, are currently considered as key sentinels in maintaining intestinal immune homeostasis. ILC3s can secrete a series of cytokines such as IL-22 to eliminate intestinal luminal antigens, promote epithelial tissue repair and mucosal barrier integrity, and regulate intestinal immunity by integrating multiple signals from the environment and the host. However, ILC3 dysfunction may be associated with the development and progression of various diseases in the gut. Therefore, in this review, we will discuss the role of ILC3 in intestinal diseases such as enteric infectious diseases, intestinal inflammation, and tumors, with a focus on recent research advances and discoveries to explore potential therapeutic targets.

Immune Responses at Host Barriers and Their Importance in Systemic Autoimmune Diseases

Host barriers such as the skin, the lung mucosa, the intestinal mucosa and the oral cavity are crucial at preventing contact with potential threats and are populated by a diverse population of innate and adaptive immune cells. Alterations in antigen recognition driven by genetic and environmental factors can lead to autoimmune systemic diseases such rheumatoid arthritis, systemic lupus erythematosus and food allergy. Here we review how different immune cells residing at epithelial barriers, host-derived signals and environmental signals are involved in the initiation and progression of autoimmune responses in these diseases. We discuss how regulation of innate responses at these barriers and the influence of environmental factors such as the microbiota can affect the susceptibility to develop local and systemic autoimmune responses particularly in the cases of food allergy, systemic lupus erythematosus and rheumatoid arthritis. Induction of pathogenic autoreactive immune responses at host barriers in these diseases can contribute to the initiation and progression of their pathogenesis.

Sexual Dimorphism in the Polarization of Cardiac ILCs through Elabela

Elabela is a component of the apelinergic system and may exert a cardioprotective role by regulating the innate immune responses. Innate lymphoid cells (ILCs) have a significant role in initiating and progressing immune-inflammatory responses. While ILCs have been intensively investigated during the last decade, little is known about their relationship with the apelinergic system and their cardiac diversity in a gender-based paradigm. In this study, we investigated the polarization of cardiac ILCs by Elabela in males versus females in a mouse model. Using flow cytometry and immunohistochemistry analyses, we showed a potential interplay between Elabela and cardiac ILCs and whether such interactions depend on sexual dimorphism. Our findings showed, for the first time, that Elabela is expressed by cardiac ILCs, and its expression is higher in females' ILC class 3 (ILC3s) compared to males. Females had higher frequencies of ILC1s, and Elabela was able to suppress T-cell activation and the expression of co-stimulatory CD28 in a mixed lymphocyte reaction assay (MLR). In conclusion, our results suggest, for the first time, a protective role for Elabela through its interplay with ILCs and that it can be used as an immunotherapeutic target in the treatment of cardiovascular disorders in a gender-based fashion.

RORγt-lineage APCs: The Aire apparent

Recent studies shed light on new populations and potential roles of Aire⁺ and RORγt⁺ antigen-presenting cells-including unique subsets with surprising properties-in immune homeostasis and host-microbe interactions.