A lipidome landscape of aging in mice.

Understanding the molecular mechanisms of aging is crucial for enhancing healthy longevity. We conducted untargeted lipidomics across 13 biological samples from mice at various life stages (2, 12, 19 and 24 months) to explore the potential link between aging and lipid metabolism, considering sex (male or female) and microbiome (specific pathogen-free or germ-free) dependencies. By analyzing 2,704 molecules from 109 lipid subclasses, we characterized common and tissue-specific lipidome alterations associated with aging. For example, the levels of bis(monoacylglycero)phosphate containing polyunsaturated fatty acids increased in various organs during aging, whereas the levels of other phospholipids containing saturated and monounsaturated fatty acids decreased. In addition, we discovered age-dependent sulfonolipid accumulation, absent in germ-free mice, correlating with Alistipes abundance determined by 16S ribosomal RNA gene amplicon sequencing. In the male kidney, glycolipids such as galactosylceramides, galabiosylceramides (Gal2Cer), trihexosylceramides (Hex3Cer), and mono- and digalactosyldiacylglycerols were detected, with two lipid classes-Gal2Cer and Hex3Cer-being significantly enriched in aged mice. Integrated analysis of the kidney transcriptome revealed uridine diphosphate galactosyltransferase 8A (UGT8a), alkylglycerone phosphate synthase and fatty acyl-coenzyme A reductase 1 as potential enzymes responsible for the male-specific glycolipid biosynthesis in vivo, which would be relevant to sex dependency in kidney diseases. Inhibiting UGT8 reduced the levels of these glycolipids and the expression of inflammatory cytokines in the kidney. Our study provides a valuable resource for clarifying potential links between lipid metabolism and aging.

A Bcl11bN797K variant isolated from an immunodeficient patient inhibits early thymocyte development in mice.

BCL11B is a transcription factor with six C2H2-type zinc-finger domains. Studies in mice have shown that Bcl11b plays essential roles in T cell development. Several germline heterozygous BCL11B variants have been identified in human patients with inborn errors of immunity (IEI) patients. Among these, two de novo mis-sense variants cause asparagine (N) to lysine (K) replacement in distinct zinc-finger domains, BCL11BN441K and BCL11BN807K. To elucidate the pathogenesis of the BCL11BN807K variant, we generated a mouse model of BCL11BN807K by inserting the corresponding mutation, Bcl11bN797K, into the mouse genome. In Bcl11b+/N797K mice, the proportion of immature CD4-CD8+ single-positive thymocytes was increased, and the development of invariant natural killer cells was severely inhibited in a T-cell-intrinsic manner. Under competitive conditions, γδT cell development was outcompeted by control cells. Bcl11bN797K/N797K mice died within one day of birth. Recipient mice reconstituted with Bcl11bN797K/N797K fetal liver cells nearly lacked CD4+CD8+ double-positive thymocytes, which was consistent with the lack of their emergence in culture from Bcl11bN797K/N797K fetal liver progenitors. Interestingly, Bcl11bN797K/N797K progenitors gave rise to aberrant c-Kit+ and CD44+ cells both in vivo and in vitro. The increase in the proportion of immature CD8 single-positive thymocytes in the Bcl11bN797K mutants is caused, in part, by the inefficient activation of the Cd4 gene due to the attenuated function of the two Cd4 enhancers via distinct mechanisms. Therefore, we conclude that immunodeficient patient-derived Bcl11bN797K mutant mice elucidated a novel role for Bcl11b in driving the appropriate transition of CD4-CD8- into CD4+CD8+ thymocytes.

Disease pathogenesis and barrier functions regulated by group 3 innate lymphoid cells.

The mucosal surface is in constant contact with foreign antigens and is regulated by unique mechanisms that are different from immune responses in the peripheral organs. For the last several decades, only adaptive immune cells such as helper T (Th) cells, Th1, Th2, or Th17 were targeted to study a wide variety of immune responses in the mucosal tissues. However, since their discovery, innate lymphoid cells (ILCs) have been attracting attention as a unique subset of immune cells that provide border defense with various functions and tissue specificity. ILCs are classified into different groups based on cell differentiation and functions. Group 3 innate lymphoid cells (ILC3s) are particularly in close proximity to mucosal surfaces and therefore have the opportunity to be exposed to a variety of bacteria including pathogenic bacteria. In recent years, studies have also provided much evidence that ILC3s contribute to disease pathogenesis as well as the defense of mucosal surfaces by rapidly responding to pathogens and coordinating other immune cells. As the counterpart of helper T cells, ILC3s together with other ILC subsets establish the immune balance between adaptive and innate immunity in protecting us from invasion or encounter with non-self-antigens for maintaining a complex homeostasis. In this review, we summarize recent advances in our understanding of ILCs, with a particular focus on the function of ILC3s in their involvement in bacterial infection and disease pathogenesis.

Possible Metastatic Stage-Dependent ILC2 Activation Induces Differential Functions of MDSCs through IL-13/IL-13Rα1 Signaling during the Progression of Breast Cancer Lung Metastasis.

Breast cancer is the most common cancer in women worldwide, and lung metastasis is one of the most frequent distant metastases. When breast cancer metastasizes to the lung, group 2 innate lymphoid cells (ILC2s) are thought to promote tumor growth via the activation of myeloid-derived suppressor cells (MDSCs), which are known to negatively regulate anticancer immune responses. However, it remains to be elucidated exactly how this ILC2-MDSC interaction is involved in tumor growth during metastases formation. Using a 4T1/LM4 breast cancer mouse model, we found that ILC2s were activated in both the micro- and macrometastatic regions, suggesting sustained activation throughout the metastatic cascades via IL-33/ST2 signaling. Consistent with IL-13 secretion from activated ILC2s, the frequencies of polymorphonuclear (PMN)- and monocytic (M)-MDSCs were also significantly elevated during the progression from micro- to macrometastatic cancer. However, the effects of ILC2-induced MDSC functionality on the microenvironment differed in a metastatic-stage-specific manner. Our findings indicate that ILC2s may induce the immunosuppressive functions of MDSCs during the later stages of metastasis. Concomitantly, ILC2 may instigate extracellular matrix remodeling by PMN-MDSC activation during the early stages of metastasis. These metastatic-stage-specific changes may contribute to metastatic tumor growth in the microenvironment of breast cancer lung metastasis.

A Japanese Herbal Formula, Daikenchuto, Alleviates Experimental Colitis by Reshaping Microbial Profiles and Enhancing Group 3 Innate Lymphoid Cells.

Daikenchuto (DKT) is one of the most widely used Japanese herbal formulae for various gastrointestinal disorders. It consists of Zanthoxylum Fructus (Japanese pepper), Zingiberis Siccatum Rhizoma (processed ginger), Ginseng radix, and maltose powder. However, the use of DKT in clinical settings is still controversial due to the limited molecular evidence and largely unknown therapeutic effects. Here, we investigated the anti-inflammatory actions of DKT in the dextran sodium sulfate (DSS)-induced colitis model in mice. We observed that DKT remarkably attenuated the severity of experimental colitis while maintaining the members of the symbiotic microbiota such as family Lactobacillaceae and increasing levels of propionate, an immunomodulatory microbial metabolite, in the colon. DKT also protected colonic epithelial integrity by upregulating the fucosyltransferase gene Fut2 and the antimicrobial peptide gene Reg3g. More remarkably, DKT restored the reduced colonic group 3 innate lymphoid cells (ILC3s), mainly RORγthigh-ILC3s, in DSS-induced colitis. We further demonstrated that ILC3-deficient mice showed increased mortality during experimental colitis, suggesting that ILC3s play a protective function on colonic inflammation. These findings demonstrate that DKT possesses anti-inflammatory activity, partly via ILC3 function, to maintain the colonic microenvironment. Our study also provides insights into the molecular basis of herbal medicine effects, promotes more profound mechanistic studies towards herbal formulae and contributes to future drug development.

Dietary Derived Micronutrients Modulate Immune Responses Through Innate Lymphoid Cells.

Innate lymphoid cells (ILCs) are a group of innate immune cells that possess overlapping features with T cells, although they lack antigen-specific receptors. ILCs consist of five subsets-ILC1, ILC2, ILC3, lymphoid tissue inducer (LTi-like) cells, and natural killer (NK) cells. They have significant functions in mediating various immune responses, protecting mucosal barrier integrity and maintaining tissue homeostasis in the lung, skin, intestines, and liver. ILCs react immediately to signals from internal and external sources. Emerging evidence has revealed that dietary micronutrients, such as various vitamins and minerals can significantly modulate immune responses through ILCs and subsequently affect human health. It has been demonstrated that micronutrients control the development and proliferation of different types of ILCs. They are also potent immunoregulators in several autoimmune diseases and play vital roles in resolving local inflammation. Here, we summarize the interplay between several essential micronutrients and ILCs to maintain epithelial barrier functions in various mucosal tissues and discuss their limitations and potentials for promoting human health.

Sepsis Induces Deregulation of IL-13 Production and PD-1 Expression in Lung Group 2 Innate Lymphoid Cells.

ABSTRACT: Deregulation of the immune system in sepsis plays the central role in the pathogenesis of multiple organ failure including septic lung injury. Group 2 innate lymphoid cells (ILC2s) have emerged as a new player in regulating immune homeostasis in the lung; however, the role of ILC2s in lung injury in sepsis remains poorly understood. Here, we investigated temporal changes in stimulatory and inhibitory receptor expression and intracellular type 2 cytokine expression of ILC2s in the lung using a cecal ligation and puncture mouse sepsis model. We found that IL-13 production by ILC2s, which were predominately composed of the resident natural ILC2 subset rather than the migratory inflammatory ILC2 subset, was reduced in the lungs of sepsis mice on day 1 and gradually restored through day 7. Although the expression levels of ST2 and inducible T-cell costimulator (stimulatory receptors) were high, IL-13 production by ILC2s was reduced while showing high programmed cell death 1 (PD-1) (inhibitory receptor) expression. Furthermore, using IL-33 knockout mice, we have shown that IL-33 regulates the capacity of ILC2s to produce IL-13, possibly through the modulation of ST2 and PD-1 expression and signaling in the septic lung. To the best of our knowledge, this is the first report showing differential costimulatory/inhibitory receptor expression on ILC2s in a septic lung in the context of an IL-33/IL-13 pathway-mediated type 2 immune response in the progression and resolution of inflammation. Our present findings contribute to a better understanding of the underlying immunological mechanism of ILC2s and may fill the critical knowledge gap regarding immune homeostasis in the lung that hampers the development of new therapeutic strategies for sepsis-induced acute lung injury.

Unraveling the Heterogeneity and Specialization of ILCs.

In this issue of Immunity, Zeis et al. report the generation of a single-cell atlas of lung innate lymphoid cells (ILCs). Their findings provide insight into the how ILCs are locally maintained, revealing in situ differentiation and diversification as mechanisms of ILC renewal and function.

The Role of Innate Lymphoid Cells in the Regulation of Immune Homeostasis in Sepsis-Mediated Lung Inflammation.

Septic shock/severe sepsis is a deregulated host immune system response to infection that leads to life-threatening organ dysfunction. Lung inflammation as a form of acute lung injury (ALI) is often induced in septic shock. Whereas macrophages and neutrophils have been implicated as the principal immune cells regulating lung inflammation, group two innate lymphoid cells (ILC2s) have recently been identified as a new player regulating immune homeostasis. ILC2 is one of the three major ILC subsets (ILC1s, ILC2s, and ILC3s) comprised of newly identified innate immune cells. These cells are characterized by their ability to rapidly produce type 2 cytokines. ILC2s are predominant resident ILCs and, thereby, have the ability to respond to signals from damaged tissues. ILC2s regulate the immune response, and ILC2-derived type 2 cytokines may exert protective roles against sepsis-induced lung injury. This focused review not only provides readers with new insights into the signaling mechanisms by which ILC2s modulate sepsis-induced lung inflammation, but also proposes ILC2 as a novel therapeutic target for sepsis-induced ALI.

Stomach microbiota, Helicobacter pylori, and group 2 innate lymphoid cells.

The stomach has been thought to host few commensal bacteria because of the existence of barriers, such as gastric acid. However, recent culture-independent, sequencing-based microbial analysis has shown that the stomach also harbors a wide diversity of microbiota. Although the stomach immune system, especially innate lymphoid cells (ILCs), has not been well elucidated, recent studies have shown that group 2 ILCs (ILC2s) are the dominant subtype in the stomach of both humans and mice. Stomach ILC2s are unique in that their existence is dependent on stomach microbiota, in sharp contrast to the lack of an impact of commensal microbiota on ILC2s in other tissues. The microbiota dependency of stomach ILC2s is partly explained by their responsiveness to interleukin (IL)-7. Stomach ILC2s express significantly higher IL-7 receptor protein levels on their surface and proliferate more in response to IL-7 stimulation in vitro than small intestinal ILC2s. Consistently, the stomach expresses much higher IL-7 protein levels than the small intestine. IL-5 secreted from stomach ILC2s promotes immunoglobulin (Ig) A production by plasma B cells. In a murine model, stomach ILC2s are important in containing Helicobacter pylori infection, especially in the early phase of infection, by promoting IgA production.

Remote cardiac rehabilitation is a good alternative of outpatient cardiac rehabilitation in the COVID-19 era.

BACKGROUND: In the wake of the coronavirus disease 2019 (COVID-19) pandemic, people need to practice social distancing in order to protect themselves from SARS-CoV-2 infection. In such stressful situations, remote cardiac rehabilitation (CR) might be a viable alternative to the outpatient CR program. METHODS: We prospectively investigated patients hospitalized for heart failure (HF) with a left ventricular ejection fraction of < 50%. As for patients who participated in the remote CR program, telephone support was provided by cardiologists and nurses who specialized in HF every 2 weeks after discharge. The emergency readmission rate within 30 days of discharge was compared among the outpatient CR, remote CR, and non-CR groups, and the EQ-5D score was compared between the outpatient CR and remote CR groups. RESULTS: The participation rate of HF patients in our remote CR program elevated during the COVID-19 pandemic. As observed in the outpatient CR group (n = 69), the emergency readmission rate within 30 days of discharge was lower in the remote CR group (n = 30) than in the non-CR group (n = 137) (P = 0.02). The EQ-5D score was higher in the remote CR group than in the outpatient CR group (P = 0.03) 30 days after discharge. CONCLUSIONS: Remote CR is as effective as outpatient CR for improving the short-term prognosis of patients hospitalized for heart failure post-discharge. This suggests that the remote CR program can be provided as a good alternative to the outpatient CR program.

Innate Lymphoid Cells: Important Regulators of Host-Bacteria Interaction for Border Defense.

Innate lymphoid cells (ILCs) are a recently discovered type of innate immune lymphocyte. They include three different groups classified by the nature of the transcription factors required for their development and by the cytokines they produce. ILCs mainly reside in tissues close to the mucosal barrier such as the respiratory and gastrointestinal tracts. Due to their close proximity to the mucosal surface, ILCs are exposed to a variety of both commensal and pathogenic bacteria. Under non-pathological conditions, ILCs have been shown to be important regulators for the maintenance of tissue homeostasis by mutual interactions with the microbiome. Besides these important functions at homeostasis, several studies have also provided emerging evidence that ILCs contribute to defense against pathogenic bacterial infection by responding rapidly to the pathogens as well as orchestrating other immune cells. In this review, we summarize recent advances in our understanding of the interactions of ILCs and bacteria, with special focus on the function of the different ILC subsets in bacterial infections.

Bacteria-Induced Group 2 Innate Lymphoid Cells in the Stomach Provide Immune Protection through Induction of IgA.

The intestinal microbiota shapes and directs immune development locally and systemically, but little is known about whether commensal microbes in the stomach can impact their immunological microenvironment. Here, we report that group 2 innate lymphoid cells (ILC2s) were the predominant ILC subset in the stomach and show that their homeostasis and effector functions were regulated by local commensal communities. Microbes elicited interleukin-7 (IL-7) and IL-33 production in the stomach, which in turn triggered the propagation and activation of ILC2. Stomach ILC2s were also rapidly induced following infection with Helicobacter pylori. ILC2-derived IL-5 resulted in the production of IgA, which coated stomach bacteria in both specific pathogen-free (SPF) and H. pylori-infected mice. Our study thus identifies ILC2-dependent IgA response that is regulated by the commensal microbiota, which is implicated in stomach protection by eliminating IgA-coated bacteria including pathogenic H. pylori.

Human gain-of-function STAT1 mutation disturbs IL-17 immunity in mice.

Gain-of-function (GOF) mutations in the gene for signal transducer and activator of transcription 1 (STAT1) account for approximately one-half of patients with chronic mucocutaneous candidiasis (CMC) disease. Patients with GOF-STAT1 mutations display a broad variety of infectious and autoimmune manifestations in addition to CMC, and those with severe infections and/or autoimmunity have a poor prognosis. The establishment of safe and effective treatments based on a precise understanding of the molecular mechanisms of this disorder is required to improve patient care. To tackle this problem, we introduced the human R274Q GOF mutation into mice [GOF-Stat1 knock-in (GOF-Stat1R274Q)]. To investigate the immune responses, we focused on the small intestine (SI), which contains abundant Th17 cells. Stat1R274Q/R274Q mice showed excess phosphorylation of STAT1 in CD4+ T cells upon IFN-γ stimulation, consistent with the human phenotype in patients with the R274Q mutation. We identified two subpopulations of CD4+ T cells, those with 'normal' or 'high' level of basal STAT1 protein in Stat1R274Q/R274Q mice. Upon IFN-γ stimulation, the 'normal' level CD4+ T cells were more efficiently phosphorylated than those from WT mice, whereas the 'high' level CD4+ T cells were not, suggesting that the level of STAT1 protein does not directly correlate with the level of pSTAT1 in the SI. Inoculation of Stat1R274Q/R274Q mice with Candida albicans elicited decreased IL-17-producing CD4+RORγt+ cells. Stat1R274Q/R274Q mice also excreted larger amounts of C. albicans DNA in their feces than control mice. Under these conditions, there was up-regulation of T-bet in CD4+ T cells. GOF-Stat1R274Q mice thus should be a valuable model for functional analysis of this disorder.

Dietary Antigens Induce Germinal Center Responses in Peyer's Patches and Antigen-Specific IgA Production.

The primary induction sites for intestinal IgA are the gut-associated lymphoid tissues (GALT), such as Peyer's patches (PPs) and isolated lymphoid follicles (ILFs). The commensal microbiota is known to contribute to IgA production in the gut; however, the role of dietary antigens in IgA production is poorly understood. To understand the effect of dietary antigens on IgA production, post-weaning mice were maintained on an elemental diet without any large immunogenic molecules. We found that dietary antigens contribute to IgA production in PPs through induction of follicular helper T cells and germinal center B cells. The role of dietary antigens in the PP responses was further confirmed by adding bovine serum albumin (BSA) into the elemental diet. Although dietary antigens are important for PP responses, they have fewer effects than the microbiota on the development and maturation of ILFs. Furthermore, we demonstrated that dietary antigens are essential for a normal antigen-specific IgA response to Salmonella typhi serovar Typhimurium infection. These results provide new insights into the role of dietary antigens in the regulation of mucosal immune responses.

Correction to: The potential of cardiac rehabilitation as a method of suppressing abdominal aortic aneurysm expansion: a pilot study.

In the original publication of the article, under the result section.

The potential of cardiac rehabilitation as a method of suppressing abdominal aortic aneurysm expansion: a pilot study.

This study is a prospective evaluation of the effectiveness of cardiac rehabilitation (CR) in terms of clinical outcomes for small abdominal aortic aneurysms (AAA) that were previously reported in a retrospective cohort study. We conducted a prospective non-randomized trial on patients with small AAA (N = 40; mean age 75.0 ± 6.6 years). Patients were enrolled into one of two groups, rehabilitation (CR) or non-rehabilitation (non-CR) group. Only CR group participated in a supervised-CR program including bicycle ergometer for 150 days. The AAA expansion rate and the risk of AAA repair were compared between two groups. We also researched the relationship between AAA expansion rate and body composition, blood IL-6 and TGFß1 levels. The CR (N = 15) and non-CR groups (N = 25) were comparable in terms their baseline data. The CR group had a significantly smaller change in the maximal AAA size (- 1.3 ± 2.4 mm/years) compared to the non-CR group (2.0 ± 3.6 mm/years) (p < 0.01). The IL-6, and TGFß1 levels were unrelated to the changes in AAA size. There was mild positive correlation between the change in systolic blood pressure from rest to exercise and the AAA expansion rate (p = 0.06). The risk of AAA repair after 12 months was lower in the CR group compared to the non-CR group (0% vs. 28%, respectively). CR in patients with small AAA significantly suppressed AAA expansion and resulted in a lowered risk of AAA repair.Clinical trial Trial name: The study of the profitability and protective effect of cardiac rehabilitation on abdominal aortic aneurysm. Number: UMIN000028237. UTL: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R0000323.

An exploratory study on the efficacy and safety of a BCAA preparation used in combination with cardiac rehabilitation for patients with chronic heart failure.

BACKGROUND: Sarcopenia is generally complicated with patients with chronic heart failure (CHF) and its presence negatively affects the course of heart failure, however effective nutritional intervention had not been elucidated yet. The primary objective of this study is to explore whether the addition of a branched-chain amino acid (BCAA) preparation for cardiac rehabilitation (CR) of patients with CHF further improves cardiopulmonary functions, skeletal muscle functions, and metabolism in comparison with conventional CR. METHODS: This is a randomized, parallel-group comparative study. The elderly patients that were participated in CR and complicated with left ventricular systolic or diastolic dysfunction are randomized into two groups, CR + BCAA and CR. 20 weeks later, the second randomization is performed, which divide subjects into two groups with and without BCAA intervention without CR. Primary outcome measure is the rate of change of the anaerobic threshold workload from baseline to post-intervention. Secondary outcome include parameters of exercise capacity, cardiac function and psychological status. DISCUSSION: In the current study the effect of a promising new intervention, BCAA, will be assessed to determine whether its addition to CR improve exercise capacity in patients with heart failure, who are generally complicated with sarcopenia. TRIAL REGISTRATION: This clinical trial was registered with the University Hospital Medical Information Network-Clinical Trials Registry (UMIN-CTR; JPRN-UMIN R000022440 ).

Understanding the immune signature fingerprint of peritoneal dialysis-related peritonitis.

Although acute peritonitis is a common and severe complication associated with peritoneal dialysis, the culture-based test used as the diagnostic criterion for this disease is often too slow to allow appropriate point-of-care diagnosis of specific bacterial infection. To address this problem, Zhang et al. report the efficacy of a novel set of immune biomarkers derived from a machine-learning algorithm applied to patient data. This fingerprint could predict major pathogenic causes of peritonitis.

Phenotypic and Functional Plasticity of Murine Intestinal NKp46+ Group 3 Innate Lymphoid Cells.

Group 3 innate lymphoid cells (ILC3) actively participate in mucosal defense and homeostasis through prompt secretion of IL-17A, IL-22, and IFN-γ. Reports identify two ILC3 lineages: a CCR6(+)T-bet(-) subset that appears early in embryonic development and promotes lymphoid organogenesis and a CCR6(-)T-bet(+) subset that emerges after microbial colonization and harbors NKp46(+) ILC3. We demonstrate that NKp46 expression in the ILC3 subset is highly unstable. Cell fate mapping using Ncr1(CreGFP) × Rosa26(RFP) mice revealed the existence of an intestinal RFP(+) ILC3 subset (Ncr1(FM)) lacking NKp46 expression at the transcript and protein levels. Ncr1(FM) ILC3 produced more IL-22 and were distinguishable from NKp46(+) ILC3 by differential CD117, CD49a, DNAX accessory molecule-1, and, surprisingly, CCR6 expression. Ncr1(FM) ILC3 emerged after birth and persisted in adult mice following broad-spectrum antibiotic treatment. These results identify an unexpected phenotypic instability within NKp46(+) ILC3 that suggests a major role for environmental signals in tuning ILC3 functional plasticity.