Deciphering the crosstalk among IL-1 and IL-10 family cytokines in intestinal immunity

The lipooligosaccharide of the gut symbiont Akkermansia muciniphila exhibits a remarkable structure and TLR signaling capacity

The cell-envelope of Gram-negative bacteria contains endotoxic lipopolysaccharides (LPS) that are recognized by the innate immune system via Toll-Like Receptors (TLRs). The intestinal mucosal symbiont Akkermansia muciniphila is known to confer beneficial effects on the host and has a Gram-negative architecture. Here we show that A. muciniphila LPS lacks the O-polysaccharide repeating unit, with the resulting lipooligosaccharide (LOS) having unprecedented structural and signaling properties. The LOS consists of a complex glycan chain bearing two distinct undeca- and hexadecasaccharide units each containing three 2-keto-3-deoxy-D-manno-octulosonic acid (Kdo) residues. The lipid A moiety appears as a mixture of differently phosphorylated and acylated species and carries either linear or branched acyl moieties. Peritoneal injection of the LOS in mice increased higher gene expression of liver TLR2 than TLR4 (100-fold) and induced high IL-10 gene expression. A. muciniphila LOS was found to signal both through TLR4 and TLR2, whereas lipid A only induced TLR2 in a human cell line. We propose that the unique structure of the A. muciniphila LOS allows interaction with TLR2, thus generating an anti-inflammatory response as to compensate for the canonical inflammatory signaling associated with LOS and TLR4, rationalizing its beneficial host interaction.

Effects of weaning American glass eels (Anguilla rostrata) with the formula diet on intestinal microbiota and inflammatory cytokines genes expression

This study aimed to investigate the effects of weaning American glass eels (Anguilla rostrata) with the formula diet on intestinal microbiota and the expression of inflammatory cytokines genes. During the feeding trial, the control group (termed IF group) was fed with initial feed for 34 days, and the experimental group (termed FF group) was fed with initial feed for 30 days, and then weaned with the formula diet for 4 days. After feeding trial, intestines were subjected to microbiota analysis using 16S rDNA high-throughput sequencing, and expression of three inflammatory cytokines genes in gut were examined by qPCR. The results indicated that the species richness and diversity of intestinal microbiota exhibited significantly higher in FF group than that in IF group (P < 0.05). At the phylum level, the core intestinal microflora was the same for two groups. The most abundant phylum was Firmicutes in IF group, while it was Proteobacteria in FF group. Five genera were significantly higher in the IF group compared with the FF group, and Bacillus was the most major enriched biomarker at genus level. Nine genera were significantly higher in the FF group compared with the IF group, and Acidovorax was the most major enriched biomarker. Weaning from initial feeding diet to formula feeding diet enhanced the expression levels of TNF-α and IL-8, and there was no significant change in IL-1β expression between the two groups. These findings would be very useful to improve the diet formulation for weaning stage of American glass eels.

The role of plasminogen activator inhibitor-2 in pneumococcal meningitis

Pneumococcal meningitis is associated with dysregulation of the coagulation cascade. Previously, we detected upregulation of cerebral plasminogen activator inhibitor-2 (PAI-2) mRNA expression during pneumococcal meningitis. Diverse functions have been ascribed to PAI-2, but its role remains unclear. We analyzed the function of SERPINB2 (coding for PAI-2) in patients with bacterial meningitis, in a well-established pneumococcal meningitis mouse model, using Serpinb2 knockout mice, and in vitro in wt and PAI-2-deficient bone marrow-derived macrophages (BMDMs). We measured PAI-2 in cerebrospinal fluid of patients, and performed functional, histopathological, protein and mRNA expression analyses in vivo and in vitro. We found a substantial increase of PAI-2 concentration in CSF of patients with pneumococcal meningitis, and up-regulation and increased release of PAI-2 in mice. PAI-2 deficiency was associated with increased mortality in murine pneumococcal meningitis and cerebral hemorrhages. Serpinb2−/− mice exhibited increased C5a levels, but decreased IL-10 levels in the brain during pneumococcal infection. Our in vitro experiments confirmed increased expression and release of PAI-2 by wt BMDM and decreased IL-10 liberation by PAI-2-deficient BMDM upon pneumococcal challenge. Our data show that PAI-2 is elevated during in pneumococcal meningitis in humans and mice. PAI-2 deficiency causes an inflammatory imbalance, resulting in increased brain pathology and mortality.

Application of the Care Bundle in Perioperative Nursing Care of the Type A Aortic Dissection

Background

To investigate the effect of the care bundle in the nursing care of the type A aortic dissection (TAAD).

Methods

A total of 161 patients with TAAD were included in the study. They were divided into control group (n=79) and care bundle group (n=82). The patients in the control group received routine nursing, while the patients in the care bundle group received routine nursing and care bundle. IL-2, IL-6 and IL-10 levels in the three periods of T0 (before anesthesia), T1 (before anesthesia to 6 h after surgery) and T2 (6–24 h after surgery), intraoperative blood loss, postoperative recovery, ICU stay time, intraoperative pressure ulcer rate, postoperative delirium rate, bloodstream infection rate and doctor satisfaction.

Results

The postoperative T and pH levels in two groups were all in the normal range. The levels of IL-2, IL-6 and IL-10 in the care bundle group at different periods were also significantly different. The levels of IL-2 and IL-10 showed an increased trend, while that of IL-6 showed a downward trend. The intraoperative blood loss, postoperative recovery and ICU stay time, intraoperative pressure sore rate, postoperative delirium rate, and bloodstream infection rate were lower, whereas doctor satisfaction was all significantly higher in care bundle group.

Conclusion

Care bundle increased the safety of the operation, and it was beneficial to the postoperative rehabilitation for TAAD patients.

Relevance to Clinical Practice

Patients with TAAD who underwent operation need higher quality care during the entire operation. Cluster nursing is the kind of the nursing model that can better meet the requirements of the intraoperative nursing quality. The intervention methods in this study include 5 core nursing measures. These measures are implemented together in a synergistic manner to effectively improve the quality of nursing care in operating room and the health outcomes of patients with TAAD. Care bundle is worthy of clinical application.

TLR22-mediated activation of TNF-α-caspase-1/IL-1β inflammatory axis leads to apoptosis of Aeromonas hydrophila-infected macrophages

Toll-like receptors (TLRs) represent first line of host defence against microbes. Amongst different TLRs, TLR22 is exclusively expressed in non-mammalian vertebrates, including fish. The precise role of TLR22 in fish-immunity remains abstruse. Herein, we used headkidney macrophages (HKM) from Clarias gariepinus and deciphered its role in fish-immunity. Highest tlr22 expression was observed in the immunocompetent organ - headkidney; nonetheless expression in other tissues suggests its possible involvement in non-immune sites also. Aeromonas hydrophila infection up-regulates tlr22 expression in HKM. Our RNAi based study suggested TLR22 restricts intracellular survival of A. hydrophila. Inhibitor and RNAi studies further implicated TLR22 induces pro-inflammatory cytokines TNF-α and IL-1β. We observed heightened caspase-1 activity and our results suggest the role of TLR22 in activating TNF-α/caspase-1/IL-1β cascade leading to caspase-3 mediated apoptosis of A. hydrophila-infected HKM. We conclude, TLR22 plays critical role in immune-surveillance and triggers pro-inflammatory cytokines leading to caspase mediated HKM apoptosis and pathogen clearance.

Endothelial Cells in the Decidual Bed Are Potential Therapeutic Targets for Preterm Birth Prevention

Preterm birth (PTB) is a syndrome with many origins. Among them, infection or inflammation are major risk factors for PTB; however, local defense mechanisms to mount anti-inflammatory responses against inflammation-induced PTB are poorly understood. Here, we show that endothelial TLR4 in the decidual bed is critical for sensing inflammation during pregnancy because mice with endothelial Tlr4 deletion are resistant to lipopolysaccharide (LPS)-induced PTB. Under inflammatory conditions, IL-6 is readily expressed in decidual endothelial cells with signal transducer and activator of transcription 3 (Stat3) phosphorylation in perivascular stromal cells, which then regulates expression of anti-inflammatory IL-10. Our observation that administration of an IL-10 neutralizing antibody predisposing mice to PTB shows IL-10's anti-inflammatory role to prevent PTB. We show that the integration of endothelial and perivascular stromal signaling can determine pregnancy outcomes. These findings highlight a role for endothelial TLR4 in inflammation-induced PTB and may offer a potential therapeutic target to prevent PTB.

Effect of Aspirin on the Intestinal Response to a Necrotic Enteritis Challenge

The effect of aspirin on intestinal lesions was evaluated in birds undergoing an experimental challenge with Clostridium perfringens as part of a model for inducing subclinical necrotic enteritis (SNE). Broilers were raised on clean wood shavings and randomly assigned to three treatments: Uninfected (U), Infected (I), and Infected + Aspirin (I+A; 0.025% acetylsalicylic acid in drinking water during days 21-25). Birds in the I and I+A groups were gavaged with Eimeria maxima on day 18 and their feed was inoculated with C. perfringens (1 × 10⁹ CFU/bird) during days 23-25. On day 26, birds were euthanatized, intestinal lesions were evaluated, and intestinal tissue was collected for qPCR assessment of genes thought to be involved in the immune response to SNE: IL-1β, IL-10, MMP-2, and MMP-7. Birds in the I+A group had more-severe and numerous lesions compared to the I group. For all genes except MMP-2, expression was upregulated in the I group compared to the U group, but did not differ between the I and I+A groups. These results indicate that aspirin exacerbated the intestinal lesions associated with this disease. Aspirin could play a role in the development of a reliable and consistent model for the induction of necrotic enteritis under experimental settings.

Macrophage spatial heterogeneity in gastric cancer defined by multiplex immunohistochemistry

Tumor-associated macrophages (TAMs), one of the most abundant immune components in gastric cancer (GC), are difficult to characterize due to their heterogeneity. Multiple approaches have been used to elucidate the issue, however, due to the tissue-destructive nature of most of these methods, the spatial distribution of TAMs in situ remains unclear. Here we probe the relationship between tumor context and TAM heterogeneity by multiplex immunohistochemistry of 56 human GC cases. Using distinct expression marker profiles on TAMs, we report seven predominant populations distributed between tumor and non-tumor tissue. TAM population-associated gene signatures reflect their heterogeneity and polarization in situ. Increased density of CD163+ (CD206-) TAMs with concurrent high CD68 expression is associated with upregulated immune-signaling and improved patient survival by univariate, but not multivariate analysis. CD68-only and CD206+ TAMs are correlated with high PDL1 expression.

Chronic Non-bacterial Osteomyelitis: A Review

Chronic non-bacterial osteomyelitis (CNO) is a rare auto-inflammatory bone disorder, with a prevalence of around one in a million patients. In the more severe form, it is referred to as chronic recurrent multifocal osteomyelitis (CRMO). We present the current knowledge on epidemiology, pathophysiology as well as diagnostic options and treatment regimens. CNO/CRMO most commonly affects children and lesions are often seen in the metaphyseal plates of the long bones, but cases have been described affecting all age groups as well as lesions in almost every bone. It is, therefore, a disease that clinicians can encounter in many different settings. Diagnosis is mainly a matter of exclusion from differential diagnoses such as bacterial osteomyelitis and cancer. Magnetic resonance imaging is the best radiological method for diagnosis coupled with a low-grade inflammation and a history of recurring episodes. Treatment is based on case reports and consists of alleviating symptoms with non-steroidal anti-inflammatory drugs since the disease is often self-limiting. Recently, more active treatments using either bisphosphonates or biological treatment are becoming more common, to prevent long term bone damage. In general, due to its rarity, much remains unclear regarding CNO/CRMO. We review the known literature on CNO/CRMO and propose areas of interest as well as possible ways to make current diagnostic criteria more detailed. We also find unifocal cases of the jaw to be a possible sub-type that may need its own set of criteria.

Circulating Lymphocytes, PD-L1 Expression on Tumor-infiltrating Lymphocytes, and Survival of Colorectal Cancer Patients with Different Mismatch Repair Gene Status

Clinical outcomes of checkpoint blockade immunotherapy on colorectal cancer (CRC) are influenced by mismatch repair (MMR) gene status, which is associated with distinct tumor immune infiltrates and systemic inflammatory response status. However, the prognostic value of PD-L1 expression and the systemic inflammatory response for patients with MMR deficiency has not been fully investigated. In this study, we examined the association of systemic inflammatory markers, PD-1/PD-L1 pathway expression, microsatellite instability (MSI) status, and clinicopathological characteristics of CRC with patient survival between MMR-deficient (dMMR) group (N=168) and MMR-proficient (pMMR) group (N=169). We found a large proportion of dMMR CRC patients displayed increased level of systemic inflammatory markers such as C-reactive protein, Neutrophil/Lymphocyte Ratio (NLR), Glasgow Prognostic Score (GPS), and low expression of PD-L1 in tumor stroma. Several systemic inflammatory markers were associated with AJCC stage only in dMMR patients. Similarly, Tumor infiltrating lymphocyte (TIL) PD-L1 or stroma PD-L1 expression was associated with AJCC stage only in dMMR patients. Circulating serum lymphocytes and TIL PD-L1 expression are both independent prognosis predictors for CRC patients. Overall, we found that dMMR CRC displayed a comprehensively distinct tumor immune microenvironment and systemic inflammatory response makers. PD-L1 expression at different location has different impacts on CRC patient survival, and the TIL PD-L1 expression might be a potential predictor for dMMR CRC patient response to anti-PD-1 therapy.

Deciphering desirable immune responses from disease models with resistant and susceptible chickens

Coccidiosis and necrotic enteritis (NE) are among the most significant diseases affecting the poultry industry. These diseases have become more prominent in the wake of policies to reduce the use of antibiotics in animal production. This has led to more research focused on better understanding the immune system and its responses to pathogen challenge, and thus developing informed strategies to exploit immune responses that can support enhanced disease resistance and growth performance. Some chicken breeds and lines show greater resistance or susceptibility to various diseases, and thus these birds maybe able to shed light on immune processes or pathways that contribute to the more resistant/susceptible state. This review attempts to identify potentially important genes that show some consistency in (relative) up or downregulation in key tissues between the resistant and susceptible chickens. For coccidiosis and NE, relative downregulation of IL-10 and (slightly less consistently) upregulation of IFN-γ appear to be features of more resistant birds. Data for IFN-α, IL-12, and IL-17D are currently less consistent. Gene expression data from NE studies have identified some potentially interesting, perhaps less well understood, immune-related genes (e.g., TCF12, BCL2, IRF2, TRAF3, TAB3, etc.,) that maybe associated with the resistant and/or susceptible phenotype. Salmonella and Campylobacter are important foodborne pathogens harbored by the chicken intestinal tract, while infectious bursal disease and infectious bronchitis are also important viral diseases of poultry. We, therefore, consider whether there are consistent features from resistant/susceptible disease models with these pathogens that relate to findings from the coccidiosis and NE studies. It is not anticipated that ideal immune responses to these pathogens will be identical but rather that consistent elements maybe identified that could help inform breeding or alternative strategies to support general disease resistance and enhanced (and efficient) flock productivity.

Intestinal Anti-Inflammatory Activity of the Aqueous Extract from Ipomoea asarifolia in DNBS-Induced Colitis in Rats

Inflammatory bowel disease is triggered by an uncontrolled immune response associated with genetic, environmental, and intestinal microbiota imbalance. Ipomoea asarifolia (IA), popularly known as “salsa” or “brave salsa”, belongs to the Convolvulaceae family. The aim of this approach was to study the preventive effect of IA aqueous extract in 2,4-dinitrobenzene sulfonic acid (DNBS)-induced colitis in rats. Rats pretreated with IA extract or sulfasalazine (SSZ) received intracolonic instillation of DNBS in 50% ethanol (v/v). IA extract presented a protective effect against intestinal inflammation, with improvement in the disease activity index and macroscopic damage. IA or SSZ significantly reduced myeloperoxidase activity, and also down-regulation of the gene expression of JNK1, NF-κβ-p65, STAT3, and decreased levels of TNFα, IL-1β, and increased IL-10, associated with a significant improvement of oxidative stress, in addition to a reduction in MDA and an increase of glutathione in colonic tissue. The protective effect of the extract was also confirmed in histological evaluation, showing preservation of the colonic cytoarchitecture. Immunohistochemical analysis revealed down-regulation of NF-κβ-p65, iNOS, IL-17, and up-regulation of SOCs-1 and MUC-2. IA extract presents antioxidant and anti-inflammatory intestinal properties, and proved to be a potential application for preventing damage induced by DNBS.

Interleukin-1α Mediates Ozone-Induced Myeloid Differentiation Factor-88-Dependent Epithelial Tissue Injury and Inflammation

Air pollution associated with ozone exposure represents a major inducer of respiratory disease in man. In mice, a single ozone exposure causes lung injury with disruption of the respiratory barrier and inflammation. We investigated the role of interleukin-1 (IL-1)-associated cytokines upon a single ozone exposure (1 ppm for 1 h) using IL-1α-, IL-1β-, and IL-18-deficient mice or an anti-IL-1α neutralizing antibody underlying the rapid epithelial cell death. Here, we demonstrate the release of the alarmin IL-1α after ozone exposure and that the acute respiratory barrier injury and inflammation and airway hyperreactivity are IL-1α-dependent. IL-1α signaling via IL-1R1 depends on the adaptor protein myeloid differentiation factor-88 (MyD88). Importantly, epithelial cell signaling is critical, since deletion of MyD88 in lung type I alveolar epithelial cells reduced ozone-induced inflammation. In addition, intratracheal injection of recombinant rmIL-1α in MyD88^acid mice led to reduction of inflammation in comparison with wild type mice treated with rmIL-1α. Therefore, a major part of inflammation is mediated by IL-1α signaling in epithelial cells. In conclusion, the alarmin IL-1α released upon ozone-induced tissue damage and inflammation is mediated by MyD88 signaling in epithelial cells. Therefore, IL-1α may represent a therapeutic target to attenuate ozone-induced lung inflammation and hyperreactivity.

STING-Dependent Signaling Underlies IL-10 Controlled Inflammatory Colitis

Intestinal immune homeostasis is preserved by commensal bacteria interacting with the host to generate a balanced array of cytokines that are essential for wound repair and for combatting infection. Inflammatory bowel disease (IBD), which can lead to colitis-associated cancer (CAC), is thought to involve chronic microbial irritation following a breach of the mucosal intestinal epithelium. However, the innate immune pathways responsible for regulating these inflammatory processes remain to be fully clarified. Here, we show that commensal bacteria influence STING signaling predominantly in mononuclear phagocytes to produce both pro-inflammatory cytokines as well as anti-inflammatory IL-10. Enterocolitis, manifested through loss of IL-10, was completely abrogated in the absence of STING. Intestinal inflammation was less severe in the absence of cGAS, possibly suggesting a role for cyclic dinucleotides (CDNs) indirectly regulating STING signaling. Our data shed insight into the causes of inflammation and provide a potential therapeutic target for prevention of IBD.

Protective effect of β-glucan and glutamine on intestinal and immunological damage in mice induced by cytarabine (Ara-C)

ABSTRACT: Recently, glutamine and β-glucan have been demonstrated to play an important role in modulation of the immune system and in promoting intestinal health benefits. The aim of this study was to investigate the effect of this intervention on inflammatory responses and intestinal health in mice orally pretreated with soluble Saccharomyces cerevisiae derived 1,3/1,6-β-glucan (80mg/kg) with or without glutamine (150mg/kg) and then challenged with cytarabine (Ara-C) (15mg/kg). Improvements in villi and crypts were not observed in the β-glucan group. The intestinal morphometry in the glutamine group showed the best results. β-glucan in combination with glutamine presented the highest values of IL-1β and IL-10 and lowest values for leukocytes and INF-γ. Based on these results, combined β-glucan and glutamine pretreatment reduced intestinal inflammation and improved the immune response after Ara-C challenge.

Cytokines IL-17 and IL-22 in the host response to infection

Cytokines IL-17 and IL-22 play pivotal roles in host defense against microbes and in the development of chronic inflammatory diseases. These cytokines are produced by cells that are often located in epithelial barriers, including subsets of T cells and innate lymphoid cells. In general, IL-17 and IL-22 can be characterized as important cytokines in the rapid response to infectious agents, both by recruiting neutrophils and by inducing the production of antimicrobial peptides. Although each cytokine induces an innate immune response in epithelial cells, their functional spectra are generally distinct: IL-17 mainly induces an inflammatory tissue response and is involved in the pathogenesis of several autoimmune diseases, whereas IL-22 is largely protective and regenerative. In this review, we compare IL-17 and IL-22, describing overlaps and differences in their cellular sources as well as their regulation, signaling, biological functions and roles during disease, with a focus on the contribution of these cytokines to the gut mucosal barrier during bacterial infection.

Analysis of the function of IL-10 in chickens using specific neutralising antibodies and a sensitive capture ELISA

In mammals, the inducible cytokine interleukin 10 is a feedback negative regulator of inflammation. To determine the extent to which this function is conserved in birds, recombinant chicken IL-10 was expressed as a secreted human Ig Fc fusion protein (chIL-10-Fc) and used to immunise mice. Five monoclonal antibodies (mAb) which specifically recognise chicken IL-10 were generated and characterised. Two capture ELISA assays were developed which detected native chIL-10 secreted from chicken bone marrow-derived macrophages (chBMMs) stimulated with lipopolysaccharide (LPS). Three of the mAbs detected intracellular IL-10. This was detected in only a subset of the same LPS-stimulated chBMMs. The ELISA assay also detected massive increases in circulating IL-10 in chickens challenged with the coccidial parasite, Eimeria tenella. The same mAbs neutralised the bioactivity of recombinant chIL-10. The role of IL-10 in feedback control was tested in vitro. The neutralising antibodies prevented IL-10-induced inhibition of IFN-γ synthesis by mitogen-activated lymphocytes and increased nitric oxide production in LPS-stimulated chBMMs. The results confirm that IL-10 is an inducible feedback regulator of immune response in chickens, and could be the target for improved vaccine efficacy or breeding strategies.

The role of barrier function, autophagy, and cytokines in maintaining intestinal homeostasis

Intestinal homeostasis is maintained through the interplay of the intestinal mucosa, local and systemic immune factors, and the microbial content of the gut. The cellular processes of autophagy, endoplasmic reticulum stress, the unfolded protein response and regulation of reactive oxygen species production are required to maintain a balance between pro-inflammatory responses against potential pathogens and a tolerogenic response towards commensal bacteria. Intestinally active cytokines regulate innate immune pathways and cellular pathways within the gut mucosa. Disruption of these processes, or alterations in the cytokine milieu, can result in an improper response to the commensal gut microbial community leading to inappropriate inflammation characteristic of conditions such as inflammatory bowel disease.

Keratin 8-deletion induced colitis predisposes to murine colorectal cancer enforced by the inflammasome and IL-22 pathway

Keratins (K) are intermediate filament proteins important in protection from cellular stress. K8, K18 and K19 are the main components of keratin filaments in colonic epithelia but their role in intestinal diseases remains ambiguous. A function for keratins in intestinal health is supported by the K8-knock-out (K8(-/-)) mouse which manifests an early chronic ulcerative colitis-like inflammatory bowel disease and epithelial hyperproliferation. We tested whether K8(-/-) mice are more susceptible to colorectal cancer (CRC) compared to K8 wild type (K8(+/+)), and K8 heterozygote (K8(+/-)) mice showing increased proliferation but no inflammation. K8(-/-) mice did not develop CRC spontaneously, but had dramatically increased numbers of tumors in the distal colon in the azoxymethane (AOM) and Apc(Min/+) CRC models while neither K8(+/+) nor K8(+/-) mice were susceptible. Upregulation of IL-22 in combination with a complete loss of its negative regulator IL-22BP, and increased downstream STAT3-signaling in K8(-/-) and K8(-/-)Apc(Min/+) colonic epithelia confirmed that the IL-22 pathway, important in inflammation, proliferation and tissue regeneration, was activated. The nearly total loss of IL-22BP correlated with an activated inflammasome leading to increased cleaved caspase-1, and the putative IL-22BP inhibitor, IL-18, as well as a decrease in ALDH1/2. Ablation of K8 in a colorectal cancer cell line similarly resulted in increased IL-18 and decreased ALDH1/2. K8/K18 co-immunoprecipitated with pro-caspase-1, a component of the inflammasome in the colon, which suggests that keratins modulate inflammasome activity and protect the colon from inflammation and tumorigenesis. The K8-null mouse models also provide novel epithelial-derived robust colon-specific CRC models.