IL-17A Produced by Innate Lymphoid Cells Is Essential for Intestinal Ischemia-Reperfusion Injury

Dendritic epidermal T cell hydrogel induces the polarization of M2 macrophages to promote the healing of deep tissue pressure injury

Dendritic epidermal T cells (DETCs) have been shown to promote wound healing. However, the mechanisms involved need to be better understood. In the present study, we investigated the role and mechanism of DETCs in deep tissue pressure injury (DTPI). We established the DTPI model using C57BL/6 mice. Then, DTPI was evaluated and analyzed by histological staining, immunohistochemistry, real-time PCR, Western blotting, and flow cytometry in different treatment groups (DETCs, DETCs/gel, Matrigel, Saline, and Normal group). The results showed that insulin-like growth factor 1 and vascular endothelial growth factor-A expression increased after local DETCs and DETCs/gel implantation in DTPI on days 3 and 7. M1 (inducible nitric oxide synthas-marked) macrophages were predominant at 3 days after DTPI. At 7 days, M1 macrophages were decreased, and M2 (CD206-marked) macrophages were increased in the DETCs and DETCs/gel groups. In vitro, in the co-culture of DETCs and RAW264.7, CD206 expression was significantly increased in M2 macrophages. In addition, Interleukin-17A initially inhibited wound healing 1 day after injury. However, it promoted wound healing at 7, 14, and 21 days after treatment with DETCs and DETCs/gel, respectively. In conclusion, our data suggest that exogenous DETCs improve DTPI wound healing by regulating M1 to M2 macrophage polarization.

Lentinula edodes Cultured Extract and Rouxiella badensis subsp. acadiensis (Canan SV-53) Intake Alleviates Immune Deregulation and Inflammation by Modulating Signaling Pathways and Epigenetic Mechanisms

Puberty is a critical developmental period of life characterized by marked physiological changes, including changes in the immune system and gut microbiota development. Exposure to inflammation induced by immune stressors during puberty has been found to stimulate central inflammation and lead to immune disturbance at distant sites from the gut; however, its enduring effects on gut immunity are not well explored. Therefore, in this study, we used a pubertal lipopolysaccharides (LPS)-induced inflammation mouse model to mimic pubertal exposure to inflammation and dysbiosis. We hypothesized that pubertal LPS-induced inflammation may cause long-term dysfunction in gut immunity by enduring dysregulation of inflammatory signaling and epigenetic changes, while prebiotic/probiotic intake may mitigate the gut immune system deregulation later in life. To this end, four-week-old female Balb/c mice were fed prebiotics/probiotics and exposed to LPS in the pubertal window. To better decipher the acute and enduring immunoprotective effects of biotic intake, we addressed the effect of treatment on interleukin (IL)-17 signaling related-cytokines and pathways. In addition, the effect of treatment on gut microbiota and epigenetic alterations, including changes in microRNA (miRNA) expression and DNA methylation, were studied. Our results revealed a significant dysregulation in selected cytokines, proteins, and miRNAs involved in key signaling pathways related to IL-17 production and function, including IL-17A and F, IL-6, IL-1β, transforming growth factor-β (TGF-β), signal transducer and activator of transcription-3 (STAT3), p-STAT3, forkhead box O1 (FOXO1), and miR-145 in the small intestine of adult mice challenged with LPS during puberty. In contrast, dietary interventions mitigated the lasting adverse effects of LPS on gut immune function, partly through epigenetic mechanisms. A DNA methylation analysis demonstrated that enduring changes in gut immunity in adult mice might be linked to differentially methylated genes, including Lpb, Rorc, Runx1, Il17ra, Rac1, Ccl5, and Il10, involved in Th17 cell differentiation and IL-17 production and signaling. In addition, prebiotic administration prevented LPS-induced changes in the gut microbiota in pubertal mice. Together, these results indicate that following a healthy diet rich in prebiotics and probiotics is an optimal strategy for programming immune system function in the critical developmental windows of life and controlling inflammation later in life.

The role of γδ T17 cells in cardiovascular disease

Due to the ability of γδ T cells to bridge adaptive and innate immunity, γδ T cells can respond to a variety of molecular cues and acquire the ability to induce a variety of cytokines such as IL-17 family, IFN-γ, IL-4, and IL-10. IL-17⁺ γδ T cells (γδ T17 cells) populations have recently received considerable interest as they are the major early source of IL-17A in many immune response models. However, the exact mechanism of γδ T17 cells is still poorly understood, especially in the context of cardiovascular disease (CVD). CVD is the leading cause of death in the world, and it tends to be younger. Here, we offer a review of the cardiovascular inflammatory and immune functions of γδ T17 cells in order to understand their role in CVD, which may be the key to developing new clinical applications.

Heartbreakers or Healers? Innate Lymphoid Cells in Cardiovascular Disease and Obesity

Cardiovascular diseases (CVDs) are responsible for most pre-mature deaths worldwide, contributing significantly to the global burden of disease and its associated costs to individuals and healthcare systems. Obesity and associated metabolic inflammation underlie development of several major health conditions which act as direct risk factors for development of CVDs. Immune system responses contribute greatly to CVD development and progression, as well as disease resolution. Innate lymphoid cells (ILCs) are a family of helper-like and cytotoxic lymphocytes, typically enriched at barrier sites such as the skin, lung, and gastrointestinal tract. However, recent studies indicate that most solid organs and tissues are home to resident populations of ILCs - including those of the cardiovascular system. Despite their relative rarity, ILCs contribute to many important biological effects during health, whilst promoting inflammatory responses during tissue damage and disease. This mini review will discuss the evidence for pathological and protective roles of ILCs in CVD, and its associated risk factor, obesity.

Dysregulated TP53 Among PTSD Patients Leads to Downregulation of miRNA let-7a and Promotes an Inflammatory Th17 Phenotype

Post-traumatic stress disorder (PTSD) is a psychiatric disorder and patients diagnosed with PTSD often express other comorbid health issues, particularly autoimmune and inflammatory disorders. Our previous reports investigating peripheral blood mononuclear cells (PBMCs) from PTSD patients showed that these patients exhibit an increased inflammatory T helper (Th) cell phenotype and widespread downregulation of microRNAs (miRNAs), key molecules involved in post-transcriptional gene regulation. A combination of analyzing prior datasets on gene and miRNA expression of PBMCs from PTSD and Control samples, as well as experiments using primary PBMCs collected from human PTSD and Controls blood, was used to evaluate TP53 expression, DNA methylation, and miRNA modulation on Th17 development. In the current report, we note several downregulated miRNAs were linked to tumor protein 53 (TP53), also known as p53. Expression data from PBMCs revealed that compared to Controls, PTSD patients exhibited decreased TP53 which correlated with an increased inflammatory Th17 phenotype. Decreased expression of TP53 in the PTSD population was shown to be associated with an increase in DNA methylation in the TP53 promotor region. Lastly, the most significantly downregulated TP53-associated miRNA, let-7a, was shown to negatively regulate Th17 T cells. Let-7a modulation in activated CD4+ T cells was shown to influence Th17 development and function, via alterations in IL-6 and IL-17 production, respectively. Collectively, these studies reveal that PTSD patients could be susceptible to inflammation by epigenetic dysregulation of TP53, which alters the miRNA profile to favor a proinflammatory Th17 phenotype.

Carbon monoxide-releasing molecule-2 protects intestinal mucosal barrier function by reducing epithelial tight-junction damage in rats undergoing cardiopulmonary resuscitation

Background

Ischemia-reperfusion injury (IRI) to the small intestine is associated with the development of systemic inflammation and multiple organ failure after cardiopulmonary resuscitation (CPR). It has been reported that exogenous carbon monoxide (CO) reduces IRI. This study aimed to assess the effects of carbon monoxide-releasing molecule-2 (CORM-2) on intestinal mucosal barrier function in rats undergoing CPR.

Methods

We established a rat model of asphyxiation-induced cardiac arrest (CA) and resuscitation to study intestinal IRI, and measured the serum levels of intestinal fatty acid-binding protein. Morphological changes were investigated using light and electron microscopes. The expression levels of claudin 3 (CLDN3), occludin (OCLN), zonula occludens 1 (ZO-1), tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), and nuclear factor kappa B (NF-κB) p65 were detected by western blotting.

Results

Compared with the sham-operated group, histological changes and transmission electron microscopy revealed severe intestinal mucosal injury in the CPR and inactive CORM-2 (iCORM-2) groups. In contrast, CORM-2 alleviated intestinal IRI. CORM-2, unlike iCORM-2, markedly decreased the Chiu's scores (2.38 ± 0.38 vs. 4.59 ± 0.34; P < 0.05) and serum intestinal fatty acid-binding protein level (306.10 ± 19.22 vs. 585.64 ± 119.84 pg/mL; P < 0.05) compared with the CPR group. In addition, CORM-2 upregulated the expression levels of tight junction proteins (CLDN3, OCLN, and ZO-1) (P < 0.05) and downregulated those of IL-10, TNF-α, and NF-кB p65 (P < 0.05) in the ileum tissue of rats that received CPR.

Conclusions

CORM-2 prevented intestinal mucosal damage as a result of IRI during CPR. The underlying protective mechanism was associated with inhibition of ischemia-reperfusion-induced changes in intestinal epithelial permeability and inflammation in intestinal tissue.

Innate Lymphoid Cells and Myocardial Infarction

Myocardial infarction results from obstruction of a coronary artery that causes insufficient blood supply to the myocardium and leads to ischemic necrosis. It is one of the most common diseases threatening human health and is characterized by high morbidity and mortality. Atherosclerosis is the pathological basis of myocardial infarction, and its pathogenesis has not been fully elucidated. Innate lymphoid cells (ILCs) are an important part of the human immune system and participate in many processes, including inflammation, metabolism and tissue remodeling, and play an important role in atherosclerosis. However, their specific roles in myocardial infarction are unclear. This review describes the current understanding of the relationship between innate lymphoid cells and myocardial infarction during the acute phase of myocardial infarction, myocardial ischemia-reperfusion injury, and heart repair and regeneration following myocardial infarction. We suggest that this review may provide new potential intervention targets and ideas for treatment and prevention of myocardial infarction.

Lack of gamma delta T cells ameliorates inflammatory response after acute intestinal ischemia reperfusion in mice

T-cells have been demonstrated to modulate ischemia–reperfusion injury (IRI) in the kidney, lung, liver, and intestine. Whereas most T-cell subpopulations contribute primarily to the antigen-specific effector and memory phases of immunity, γδ-T-cells combine adaptive features with rapid, innate-like responses that can place them in the initiation phase of immune reactions. Therefore, we aimed to clarify the role of γδ-T-cells in intestinal IRI. Adult wild-type (WT) and γδ-T-cell-deficient mice were subjected to acute intestinal IRI. Gene expression of pro-inflammatory cytokines and influx of leukocyte subpopulations in the gut were assessed by qPCR and flow cytometry. Serum transaminases were measured as an indicator of distant organ IRI. Intestinal IRI led to increased influx of neutrophils, pro-inflammatory cytokine expression and LDH/ALT/AST elevation. Selective deficiency of γδ-T-cells significantly decreased pro-inflammatory cytokine levels and neutrophil infiltration in the gut following IRI compared to controls. Furthermore, γδ-T-cell deficiency resulted in decreased LDH and transaminases levels in sera, indicating amelioration of distant organ injury. Increasing evidence demonstrates a key role of T-cell subpopulations in IRI. We demonstrate that γδ-T-cell deficiency ameliorated pro-inflammatory cytokine production, neutrophil recruitment and distant organ injury. Thus, γδ-T-cells may be considered as mediators contributing to the inflammatory response in the acute phase of intestinal IRI.

Lung Edema and Mortality Induced by Intestinal Ischemia and Reperfusion Is Regulated by VAChT Levels in Female Mice

Acute lung injury induced by intestinal ischemia/reperfusion (I/R) is a relevant clinical condition. Acetylcholine (ACh) and the α7 nicotinic ACh receptor (nAChRα-7) are involved in the control of inflammation. Mice with reduced levels of the vesicular ACh transporter (VAChT), a protein responsible for controlling ACh release, were used to test the involvement of cholinergic signaling in lung inflammation due to intestinal I/R. Female mice with reduced levels of VAChT (VAChT-KD^HOM) or wild-type littermate controls (WT) were submitted to intestinal I/R followed by 2 h of reperfusion. Mortality, vascular permeability, and recruitment of inflammatory cells into the lung were investigated. Parts of mice were submitted to ovariectomy (OVx) to study the effect of sex hormones or treated with PNU-282,987 (nAChRα-7 agonist). A total of 43.4% of VAChT-KD^HOM-I/R mice died in the reperfusion period compared to 5.2% of WT I/R mice. The I/R increased lung inflammation in both genotypes. In VAChT-KD^HOM mice, I/R increased vascular permeability and decreased the release of cytokines in the lung compared to WT I/R mice. Ovariectomy reduced lung inflammation and permeability compared to non-OVx, but it did not avoid mortality in VAChT-KD^HOM-I/R mice. PNU treatment reduced lung permeability, increased the release of proinflammatory cytokines and the myeloperoxidase activity in the lungs, and prevented the increased mortality observed in VAChT-KD^HOM mice. Cholinergic signaling is an important component of the lung protector response against intestinal I/R injury. Decreased cholinergic signaling seems to increase pulmonary edema and dysfunctional cytokine release that increased mortality, which can be prevented by increasing activation of nAChRα-7.

Absence of the C5a Receptor C5aR2 Worsens Ischemic Tissue Injury by Increasing C5aR1-Mediated Neutrophil Infiltration

Neutrophil infiltration to ischemic tissues following reperfusion worsens injury. A key driver of neutrophil recruitment and activation is the complement factor C5a, which signals through two receptors, C5aR1 and C5aR2. In this study, we used a neutrophil-dependent mouse model of intestinal ischemia-reperfusion (IR) injury to investigate the underexplored role of C5aR2 in neutrophil mobilization, recruitment, and disease outcomes. We show that intestinal IR induces rapid neutrophil mobilization along with a concomitant reduction in plasma C5a levels that is driven by both C5aR1 and C5aR2. Intestinal IR in C5aR2^-/- mice led to worsened intestinal damage and increased neutrophil infiltration. Inhibition of C5aR1 signaling in C5aR2^-/- mice with PMX53 prevented neutrophil accumulation and reduced IR pathology, suggesting a key requirement for enhanced neutrophil C5aR1 activation in the absence of C5aR2 signaling. Interestingly, C5aR2 deficiency also reduced circulating neutrophil numbers after IR, as well as following G-CSF-mediated bone marrow mobilization, which was independent of C5aR1, demonstrating that C5aR2 has unique and distinct functions from C5aR1 in neutrophil egress. Despite enhanced tissue injury in C5aR2^-/- IR mice, there were significant reductions in intestinal proinflammatory cytokines, highlighting complicated dual protective/pathogenic roles for C5aR2 in pathophysiology. Collectively, we show that C5aR2 is protective in intestinal IR by inhibiting C5aR1-mediated neutrophil recruitment to the ischemic tissue. This is despite the potentially local pathogenic effects of C5aR2 in increasing intestinal proinflammatory cytokines and enhancing circulating neutrophil numbers in response to mobilizing signals. Our data therefore suggest that this balance between the dual pro- and anti-inflammatory roles of C5aR2 ultimately dictates disease outcomes.

Effects of endothelin receptor blockade and COX inhibition on intestinal I/R injury in a rat model: Experimental research

BACKGROUND

Intestinal ischemia is a highly morbid and mortal condition with no specific treatment. The present study aimed to investigate the effects of cyclooxygenase (COX) inhibition synchronized with nitric oxide (NO) release and endothelin (ET) receptor blockade on oxidative stress, inflammation, vasoconstriction, and bacterial translocation which occur during ischemia-reperfusion (I/R) injury in in-vivo rat intestinal I/R model.

MATERIALS AND METHODS

36 male Wistar rats were randomly divided into six groups (n = 6). Superior mesenteric artery blood flow (SMABF) was recorded; SMA was occluded for 30 min; SMABF was re-recorded at the beginning of the reperfusion phase. Rats were sacrificed after the reperfusion period of 60 min. Blood and tissue samples were obtained. Acetylsalicylic acid (ASA), NO-ASA, flurbiprofen (FLUR), and Tezosentan (TS) were administered 15 min after ischemia. Histopathological examination, bacterial translocation, and biochemical analysis were performed in plasma and tissue samples.

RESULTS

SMABF difference, mean Chiu's score and bacterial translocation were increased in the I/R group and decreased in the treatment groups. Plasma LDH, transaminases, intestinal fatty acid-binding protein (I-FABP), TNF-α, ICAM-1, interferon-gamma (IFN-Ɣ) and proinflammatory cytokine panel; tissue lipid peroxidation, MPO, xanthine oxidase (XO), NO, NF-kB levels and the expression of TNF-α were significantly elevated in the I/R group and markedly decreased in the treatment groups. The tissue antioxidant status was decreased in the I/R group and increased in the treatment groups.

CONCLUSION

It is suggested that NO-ASA, TS, and FLUR can be introduced as promising therapeutics to improve intestinal I/R injury.

INSTITUTIONAL PROTOCOL NO

2018-29-05 (Animal Experimentations Ethics Committee, Hacettepe University).

The role of thrombospondin-1 in the pathogenesis of antiphospholipid syndrome

OBJECTIVE

Antiphospholipid syndrome (APS) is an acquired thrombophilia characterized by recurrent thrombosis and/or pregnancy morbidity, in the presence of antibodies to β2 glycoprotein-I (β2GPI), prothrombin or Lupus anticoagulant (LA). Anti-β2GPI antibodies recognize complexes of β2GPI dimers with CXCL4 chemokine and activate platelets. Thrombospondin 1 (TSP-1) is secreted by platelets and exhibits prothrombotic and proinflammatory properties. Therefore, we investigated its implication in APS.

METHODS

Plasma from APS patients (n = 100), Systemic Lupus Erythematosus (SLE) (n = 27) and healthy donors (HD) (n = 50) was analyzed for TSP-1, IL-1β, IL-17A and free active TGF-β1 by ELISA. Human Umbilical Vein Endothelial Cells (HUVECs) and HD monocytes were treated with total HD-IgG or anti-β2GPI, β2GPI and CXCL4 and CD4⁺ T-cells were stimulated by monocyte supernatants. TSP-1, IL-1β, IL-17A TGF-β1 levels were quantified by ELISA and Real-Time PCR.

RESULTS

Higher plasma levels of TSP-1 and TGF-β1, which positively correlated each other, were observed in APS but not HDs or SLE patients. Patients with arterial thrombotic events or those undergoing a clinical event had the highest TSP-1 levels. These patients also had detectable IL-1β, IL-17A in their plasma. HD-derived monocytes and HUVECs stimulated with anti-β2GPI-IgG-β2GPI-CXCL4 secreted the highest TSP-1 and IL-1β levels. Supernatants from anti-β2GPI-β2GPI-CXCL4 treated monocytes induced IL-17A expression from CD4⁺ T-cells. Transcript levels followed a similar pattern.

CONCLUSIONS

TSP-1 is probably implicated in the pathogenesis of APS. In vitro cell treatments along with high TSP-1 levels in plasma of APS patients suggest that high TSP-1 levels could mark a prothrombotic state and an underlying inflammatory process.

IL-17A - A regulator in acute inflammation: Insights from in vitro, in vivo and in silico studies

Acute inflammation following sterile injury is both inevitable and necessary to restore homeostasis and promote tissue repair. However, when excessive, inflammation can jeopardize the viability of organs and cause detrimental systemic effects. Identifying key-regulators of the immune cascade induced by surgery is vital to attenuating excessive inflammation and its subsequent effects. In this review, we describe the emerging role of IL-17A as a key-regulator in acute inflammation. The role of IL-17A in chronic disease states, such as rheumatoid arthritis, psoriasis and cancer has been well documented, but its significance in acute inflammation following surgery, sepsis, or traumatic injury has not been well studied. We aim to highlight the role of IL-17A in acute inflammation caused by trauma, liver ischemia, and organ transplantation, as well as in post-operative surgical infections. Further investigation of the roles of this cytokine in acute inflammation may stimulate novel therapies or diagnostic modalities.