Activation Of Innate Immune System Research Articles

Activation of the Innate Immune System in Brain-Dead Donors Can Be Reduced by Luminal Intestinal Preservation During Organ Procurement Surgery - A Porcine Model.

Organs obtained from brain dead donors can have suboptimal outcomes. Activation of the innate immune system and translocation of intestinal bacteria could be causative. Thirty two pigs were assigned to control, brain death (BD), BD + luminal intestinal polyethylene glycol (PEG), and BD + luminal intestinal University of Wisconsin solution (UW) groups. Animals were observed for 360min after BD before organ retrieval. 2,000mL luminal intestinal preservation solution was instilled into the duodenum at the start of organ procurement. Repeated measurements of plasma C3a, Terminal Complement Complex (TCC), IL-8, TNF, and lipopolysaccharide binding protein were analysed by immunoassays. C3a was significantly higher in the BD groups compared to controls at 480min after brain death. TCC was significantly higher in BD and BD + UW, but not BD + PEG, compared to controls at 480min. TNF was significantly higher in the BD group compared to all other groups at 480min. LPS binding protein increased following BD in all groups except BD + PEG, which at 480min was significantly lower compared with all other groups. Brain death induced innate immune system activation was decreased by luminal preservation using PEG during organ procurement, possibly due to reduced bacterial translocation.

Adenosine triphosphate: a new player in complex regional pain syndrome type 1.

The complex regional pain syndrome type 1 (CRPS-1) is one of the most discussed painful syndromes due to the variability and severity of its symptoms. CRPS-1 generally occurs after a trauma, a fracture or a sprain followed by an immobilization. Classical diagnostic criteria are not always clear; hence, the diagnosis is difficult. The definition of CRPS itself defines and considers the pain as key symptom neglecting the bone damage. Early CRPS involves the activation of the innate cutaneous immune system with altered sensory and sympathetic signaling, activation and proliferation of keratinocytes and mast cells in addition to the release of inflammatory mediators and pain. The role of the immune system and the response to the disease is becoming clearer as the microglia is activated as a result of injury and can induce a central sensitization while astrocytes can maintain the process. Adenosine triphosphate (ATP) exerts a fundamental role in the activation of innate cutaneous immune system, in the proliferation of keratinocytes and mast cells, in the release of several proinflammatory cytokines and in the microglia activation. It is essential to intervene on this pathology as soon as possible with drugs, as clodronate, able to reduce bone marrow edema and pain through the inhibition of the primary inflammatory process and the immune reaction, limiting the activation of macrophages and the release of cytokines activating nuclear growth factor (NGF). In this review the role of ATP, bisphosphonates and rehabilitation are discussed.

Replication properties of a contemporary Zika virus from West Africa.

Zika virus (ZIKV) has become a global health problem over the past decade due to the extension of the geographic distribution of the Asian/American genotype. Recent epidemics of Asian/American ZIKV have been associated with developmental disorders in humans. There is mounting evidence that African ZIKV may be associated with increased fetal pathogenicity necessitating to pay a greater attention towards currently circulating viral strains in sub-Saharan Africa. Here, we generated an infectious molecular clone GUINEA-18 of a recently transmitted human ZIKV isolate from West Africa, ZIKV-15555. The available infectious molecular clone MR766MC of historical African ZIKV strain MR766-NIID was used for a molecular clone-based comparative study. Viral clones GUINEA-18 and MR766MC were compared for their ability to replicate in VeroE6, A549 and HCM3 cell lines. There was a lower replication rate for GUINEA-18 associated with weaker cytotoxicity and reduced innate immune system activation compared with MR766MC. Analysis of chimeric viruses between viral clones stressed the importance of NS1 to NS4B proteins, with a particular focus of NS4B on GUINEA-18 replicative properties. ZIKV has developed strategies to prevent cytoplasmic stress granule formation which occurs in response to virus infection. GUINEA-18 was greatly efficient in inhibiting stress granule assembly in A549 cells subjected to a physiological stressor, with NS1 to NS4B proteins also being critical in this process. The impact of these GUINEA-18 proteins on viral replicative abilities and host-cell responses to viral infection raises the question of the role of nonstructural proteins in the pathogenicity of currently circulating ZIKV in sub-Saharan Africa.

Additive aluminum as a cause of induced immunoexcitoxicity resulting in neurodevelopmental and neurodegenerative disorders: A biochemical, pathophysiological, and pharmacological analysis.

Much has been learned about the neurotoxicity of aluminum over the past several decades in terms of its ability to disrupt cellular function, result in slow accumulation, and the difficulty of its removal from cells. Newer evidence suggests a central pathophysiological mechanism may be responsible for much of the toxicity of aluminum and aluminofluoride compounds on the brain and spinal cord. This mechanism involves activation of the brain's innate immune system, primarily the microglia, astrocytes, and macrophages, with a release of neurotoxic concentrations of excitotoxins and proinflammatory cytokines, chemokines, and immune mediators. Many studies suggest that excitotoxicity plays a significant role in the neurotoxic action of several metals, including aluminum. Recently, researchers have found that while most of the chronic pathology involved in the observed neurodegenerative effects of these metals are secondary to prolonged inflammation, it is the enhancement of excitotoxicity by the immune mediators that are responsible for most of the metal's toxicity. This enhancement occurs through a crosstalk between cytokines and glutamate-related mechanisms. The author coined the name immunoexcitotoxicity to describe this process. This paper reviews the evidence linking immunoexcitotoxicity to aluminum's neurotoxic effects and that a slow accumulation of aluminum may be the cause of neurodevelopmental defects as well as neurodegeneration in the adult.

Risk for cancer development in familial Mediterranean fever and associated predisposing factors: an ambidirectional cohort study from the international AIDA Network registries.

Inflammation has been associated with an increased risk for cancer development, while innate immune system activation could counteract the risk for malignancies. Familial Mediterranean fever (FMF) is a severe systemic inflammatory condition and also represents the archetype of innate immunity deregulation. Therefore, the aim of this study is to investigate the risk for cancer development in FMF. The risk ratio (RR) for malignancies was separately compared between FMF patients and fibromyalgia subjects, Still's disease patients and Behçet's disease patients. Clinical variables associated with cancer development in FMF patients were searched through binary logistic regression. 580 FMF patients and 102 fibromyalgia subjects, 1012 Behçet's disease patients and 497 Still's disease patients were enrolled. The RR for the occurrence of malignant neoplasms was 0.26 (95% Confidence Interval [CI.] 0.10-0.73, p=0.006) in patients with FMF compared to fibromyalgia subjects; the RR for the occurrence of malignant cancer was 0.51 (95% CI. 0.23-1.16, p=0.10) in FMF compared to Still's disease and 0.60 (95% CI. 0.29-1.28, p=0.18) in FMF compared to Behçet's disease. At logistic regression, the risk of occurrence of malignant neoplasms in FMF patients was associated with the age at disease onset (β1 = 0.039, 95% CI. 0.001-0.071, p=0.02), the age at the diagnosis (β1 = 0.048, 95% CI. 0.039-0.085, p=0.006), the age at the enrolment (β1 = 0.05, 95% CI. 0.007-0.068, p=0.01), the number of attacks per year (β1 = 0.011, 95% CI. 0.001- 0.019, p=0.008), the use of biotechnological agents (β1 = 1.77, 95% CI. 0.43-3.19, p=0.009), the use of anti-IL-1 agents (β1 = 2.089, 95% CI. 0.7-3.5, p=0.002). The risk for cancer is reduced in Caucasic FMF patients; however, when malignant neoplasms occur, this is more frequent in FMF cases suffering from a severe disease phenotype and presenting a colchicine-resistant disease.

Acute Exposure to High-Altitude Results in Changes to Immune Cell Populations

High altitude is a challenging environment due to the reduced atmospheric pressure and oxygen availability, increased ultraviolet radiation, and reduced temperature relative to sea level. Previous studies in individuals who travel to high altitude demonstrate differential expression of genes involved in inflammation and innate immune system activation. This study aims to extend these findings by defining changes in immune cell population distributions and cell phenotypes during travel to high altitude. We hypothesized that acute high-altitude exposure would lead to shifts in immune cell populations toward a pro-inflammatory phenotype due to cellular stress caused by hypoxemia and tissue hypoxia. Participants (N=17) traveled to Barcroft Station in the White Mountain Research Center (3800 m). Whole blood was collected during fasting at sea level on the morning of ascent and each morning at high altitude for three days. Cells in whole blood were fixed and stained within 1-2 hours of collection and were processed via flow cytometry upon return to sea level. We observed a decrease in classical monocytes on the first (p=0.010) and second (p=0.003) mornings of high-altitude acclimatization to sea-level baseline, and an increase in intermediate monocytes on the first (p=0.013) and second (p=0.014) mornings at high altitude. We also observed an increase in B cells on the second (p=0.004) and third (p=0.004) mornings at high altitude compared to sea-level baseline (mean: 3.53%, SD: ±1.82). These results indicate that acute high altitude exposure results in a shift toward a pro-inflammatory monocyte phenotype and supports prior research suggesting a significant role of hypoxia in modulating B cell function. This research was supported through funding provided by a private donor. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

An Exploration of Some Predictors of Quality of Life-Related to the Innate Immune System, Inflammation, and Disease Activity in Patients with Behcet's Syndrome: An Analytical Cross-sectional Study.

Behçet's disease (BD) has a growing prevalence in Silk Road countries. The aim of our cross-sectional study was to explore the clinical and molecular predictors of quality of life in BD patients. One hundred and fifty consecutive Iranian BD patients with an age range between 20-50 years were included. The Leeds Behçet's disease quality of life (BDQoL) in Persian form was fulfilled to evaluate the quality of life. Anthropometric measurements were carried out using the calibrated scales. Iranian Behcet's Disease Dynamic Activity Measure (IBDDAM), Behcet's disease current activity form (BDCAF), and Total Inflammatory Activity Index (TIAI) were used to assess BD activity. mRNA expression of toll-like receptors 2 and 4 (TLR2 and TLR4) and tumor-necrosis-factor-alpha (TNF-α) levels in serum were measured by real-time polymerase chain reaction (PCR) and ELISA, respectively. Multiple linear backward regression at P = 0.1 was used to study the potential predictors of quality of life. TLR2 and BDCAF were shown to be the most important predictors of quality of life in BD patients by 22%. There were positive associations between them (β = 0.326, p = 0.013 for BDCAF; β = 0.366, p = 0.006 for TLR2) and BDQoL value. Higher TLR2 expression as a key protein in recognizing pathogens by innate immunity and BDCAF value as a comprehensive BD assessing scale contribute to poor quality of life among BD patients. Emphasizing therapeutically, approaches associated with lower TLR2 expression and BDCAF value can be considered in future studies.

Impact of chronic muscle use and disuse on innate immune signaling in skeletal muscle

Mitochondria exhibit high levels of adaptability to various stimuli such as chronic muscle use (i.e. exercise) or disuse, such as immobilization or denervation. These changes in the mitochondrial network ultimately affect the health and functioning of skeletal muscle, which contributes to whole-body metabolism, locomotion, and postural stability. It is now acknowledged that mitochondrial dysfunction can activate inflammatory pathways through the recognition of damage-associated molecular patterns (DAMPs). The objective of this study was to examine how changes in mitochondria brought about by either chronic muscle inactivity or chronic exercise training affect innate immune system activation. We hypothesized that an inverse relationship between mitochondrial content and innate immune signaling would be evident in skeletal muscle. To investigate this, skeletal muscle from the hindlimbs of mice was collected after 7 days of sciatic muscle denervation, or after 4.5 weeks of endurance swim training involving 240 minutes of daily exercise. We analyzed the expression of the NLRP3 inflammasome, innate immune system signaling proteins, mitochondrial markers, and mitochondrial DNA (mtDNA) content using western blotting, cytochrome C oxidase (COX) activity, ELISA and qPCR. Following 7 days of denervation, there was a significant decrease in both COX-IV protein and COX activity, indicating a reduction in mitochondrial content. This was accompanied by an increase (p<0.05) in NLRP3, procaspase-1, gasdermin-D (GSDMD) and its active N-terminal fragment, GSDMD-N, as well as a notable increase in IL-1β. In addition, other possible converging pathways were also upregulated including cGAS-STING, and gasdermin-E. In comparison, following exercise training, there was a significant increase in mitochondrial content, apparent through increases in COX-IV protein, COX activity and mitochondrial RNA content. This was associated with decreases in procaspase-1 and caspase-1 protein expression alongside reduced STING activation. These findings highlight an inverse relationship between mitochondrial content and the activation of several inflammatory pathways that possibly converge upon NLRP3 inflammasome activation and pyroptotic cell death, leading to detriments in skeletal muscle health. This work aims to further the understanding of innate immune signaling pathways within muscle which can potentially highlight therapeutic targets to regulate its activation under divergent metabolic conditions. This work was supported by funds from the Natural Science and Engineering Research Council (NSERC). Priyanka Khemraj is the holder of an Ontario Graduate Scholarship. David A. Hood is the holder of a Canadian Research Chair in Cell Physiology. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Biological Response Following the Systemic Injection of PEG-PAMAM-Rhodamine Conjugates in Zebrafish.

Numerous therapeutic and diagnostic approaches used within a clinical setting depend on the administration of compounds via systemic delivery. Biomaterials at the nanometer scale, as dendrimers, act as delivery systems by improving cargo bioavailability, circulation time, and the targeting of specific tissues. Although evaluating the efficacy of pharmacological agents based on nanobiomaterials is crucial, conducting toxicological assessments of biomaterials is essential for advancing clinical translation. Here, a zebrafish larvae model was explored to assess the biocompatibility of poly(amido amine) (PAMAM), one of the most exploited dendrimers for drug delivery. We report the impact of a systemic injection of polyethylene glycol (PEG)-modified G4 PAMAM conjugated with rhodamine (Rho) as a mimetic drug (PEG-PAMAM-Rho) on survival, animal development, inflammation, and neurotoxicity. A concentration- and time-dependent effect was observed on mortality, developmental morphology, and innate immune system activation (macrophages). Significant effects in toxicological indicators were reported in the highest tested concentration (50 mg/mL PEG-PAMAM-Rho) as early as 48 h post-injection. Additionally, a lower concentration of PEG-PAMAM-Rho (5 mg/mL) was found to be safe and subsequently tested for neurotoxicity through behavioral assays. In accordance, no significative signs of toxicity were detected. In conclusion, the dose response of the animal was assessed, and the safe dosage for future use in theragnostics was defined. Additionally, new methodologies were established that can be adapted to further studies in toxicology using other nanosystems for systemic delivery.

Macrophage activation markers are associated with infection and mortality in patients with acute liver failure.

Acute liver failure is a multisystem disorder with a high mortality and frequent need for emergency liver transplantation. Following massive innate immune system activation, soluble markers of macrophage activation are released during liver damage and their association with disease severity and prognosis requires exploration. Patients ALF from the United States Acute Liver Failure Study Group (USALFSG, n = 224) and King's College Hospital (n = 40) together with healthy controls (HC, n = 50) were recruited. Serum from early (Days 1-3) and late (>Day 3) time points were analysed for MAMs by enzyme-linked immunosorbent assay correlated to markers of illness severity and 21-day spontaneous survival. Surface expression phenotyping was performed via Flow Cytometry on CD14+ monocytes. All MAMs serum concentrations were significantly higher in ALF compared to controls (p < .0001). sCD206 concentration was higher in early and late stages of the disease in patients with bacteraemia (p = .002) and infection in general (p = .006). In MELD-adjusted multivariate modelling, sCD206 and sCD163 were independently associated with mortality. CD14+ monocyte expression of CD206 (p < .001) was higher in patients with ALF compared with controls and correlated with SOFA score (p = .018). sCD206 was independently validated as a predictor of infection in an external cohort. sCD206 is increased in serum of ALF patients with infections and poor outcome and is upregulated on CD14+ monocytes. Later measurements of sCD163 and sCD206 during the evolution of ALF have potential as mechanistic predictors of mortality. sCD206 should be explored as a biomarker of sepsis and mortality in ALF.

Abstract 2836: Assessment of therapeutic antibody efficacy without the interference of murine Fc receptors allows for investigation of human antibody-dependent cellular cytotoxicity mediated by NK cells in the FcResolv™ hIL-15 NOG mouse model

Abstract Targeted antibody therapy is applied to treat various cancer types. In addition to the primary mode of action (MOA), which involves direct binding to the tumor antigen, indirect MOA acting through the constant region (Fc) of the antibody can enhance anti-tumor efficacy. Indirect mechanisms engage the innate immune system, mediated by both the complement system (complement-dependent cytotoxicity (CDC)) and immune cells (antibody-dependent cellular phagocytosis (ADCP) and antibody-dependent cellular cytotoxicity (ADCC)). These indirect mechanisms can complicate the evaluation and accurate assessment of antibody-induced ADCC by human NK cells in current mouse models. In immune-deficient mouse strains (e.g. NOG), false positives and/or negatives may occur due to interactions with murine Fc receptors. These can either result in anti-tumor responses via activation of the murine innate immune system or can interfere with the human-targeted therapy's primary MOA. To study the response to anti-cancer antibodies without the interference of these murine Fc receptor interactions and to investigate ADCC mediated by human NK cells, a novel mouse model deficient in Fc receptors and expressing human IL-15 (FcResolv™ hIL-15 NOG) was employed for testing antibody therapies. Methods: Patient-derived xenograft (PDX) tumor models were transplanted into hIL-15 NOG and FcResolv™ hIL-15 NOG mice. A human head and neck squamous cell carcinoma and a lung adenocarcinoma PDX model were both treated with cetuximab. Treatment with pertuzumab and trastuzumab was applied in a breast ductal carcinoma PDX model. Rituximab treatment was tested in two diffuse large B cell lymphoma PDX models. Based on growth kinetics, the lung cancer PDX model was chosen for further testing of ADCC in the NK cell-humanized FcResolv™ hIL-15 NOG mouse. Results and Conclusion: There was no difference in percent tumor growth inhibition between the FcResolv™ hIL-15 NOG and hIL-15 NOG mice with regards to cetuximab treatment in the lung and head and neck cancer or for trastuzumab treatment of breast ductal carcinoma. However, pertuzumab treatment revealed a false positive efficacy, with the false positive effect more pronounced in hIL-15 NOG mice than in FcResolv™ hIL-15 NOG mice. In one of the lymphoma models, a false negative result was observed. Here, rituximab did not show notable tumor inhibition in the hIL-15 NOG mice but did in the FcResolv™ hIL-15 NOG mice. These results demonstrate that FcResolv™ hIL-15 NOG mice serve as a suitable mouse model for a more accurate assessment of the therapeutic efficacy of anti-tumor antibodies. Additionally, evaluation of human-mediated ADCC of therapeutic antibodies in NK cell-humanized FcResolv™ hIL-15 NOG allows detection of effects specifically mediated by human NK cells. Citation Format: Simone Rhein, Maria Stecklum, Monika Buczek, Janell Richardson, Jens Hoffmann. Assessment of therapeutic antibody efficacy without the interference of murine Fc receptors allows for investigation of human antibody-dependent cellular cytotoxicity mediated by NK cells in the FcResolv™ hIL-15 NOG mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2836.

Interpersonal violence exposure and inflammation during adolescence and young adulthood

Exposure to violence increases young peoples’ risk of developing mental and physical health problems. Chronic stress-related upregulation of innate immune system activity and the development of low-grade inflammation may partially underlie this health risk. However, much of the previous research has been limited to cross-sectional studies utilizing between-person analytic designs, susceptible to confounding by unmeasured factors. In this six-wave panel study of N=157 female adolescents and young adults, we tested within-person associations between interpersonal violence exposure and multiple measures of inflammatory activity. Ex vivo culture studies suggested that participants’ immune cells were more reactive to microbial stimulation and less sensitive to inhibition by glucocorticoids after violence. Numbers of circulating monocyte cells increased after violence, but serum levels of interleukin-6 and c-reactive protein did not. Findings from this within-person analysis suggest that violence exposure up-regulates innate immune system activity during adolescence and young adulthood in ways that may increase mental and physical health risk.

Cell-cycle inhibition and immune microenvironment in breast cancer treated with ribociclib and letrozole or chemotherapy

In this study, we performed genomic analyses of cell cycle and tumor microenvironment changes during and after ribociclib and letrozole or chemotherapy in the CORALLEEN trial. 106 women with untreated PAM50-defined Luminal B early breast cancers were randomly assigned to receive neoadjuvant ribociclib and letrozole or standard-of-care chemotherapy. Ki67 immunohistochemistry, tumor-infiltrating lymphocytes quantification, and RNA sequencing were obtained from tissue biopsies pre-treatment, on day 14 of treatment, and tumor specimens from surgical resection. Results showed that at surgery, Ki67 and the PAM50 proliferation scores were lower after ribociclib compared to chemotherapy. However, consistent reactivation of tumor cell proliferation from day 14 to surgery was only observed in the ribociclib arm. In tumors with complete cell cycle arrest (CCCA) at surgery, PAM50 proliferation scores were lower in the ribociclib arm compared to chemotherapy (p < 0.001), whereas the opposite was observed with tumor cellularity (p = 0.002). Gene expression signatures (GES) associated with antigen-presenting cells (APCs) and innate immune system activity showed increased expression post-chemotherapy but decreased expression post-ribociclib. Interferon-associated GES had decreased expression with CCCA and increased expression with non-CCCA. Our findings suggest that while both treatment strategies decreased proliferation, the depth and the patterns over time differed by treatment arm. Immunologically, ribociclib was associated with downregulated GES associated with APCs and the innate immune system in Luminal B tumors, contrary to existing preclinical data. Further studies are needed to understand the effect of CDK4/6 inhibition on the tumor cells and microenvironment, an effect which may vary according to tumor subtypes.

Mitochondrial DNA replication stress triggers a pro-inflammatory endosomal pathway of nucleoid disposal.

Mitochondrial DNA (mtDNA) encodes essential subunits of the oxidative phosphorylation system, but is also a major damage-associated molecular pattern (DAMP) that engages innate immune sensors when released into the cytoplasm, outside of cells or into circulation. As a DAMP, mtDNA not only contributes to anti-viral resistance, but also causes pathogenic inflammation in many disease contexts. Cells experiencing mtDNA stress caused by depletion of the mtDNA-packaging protein, transcription factor A, mitochondrial (TFAM) or during herpes simplex virus-1 infection exhibit elongated mitochondria, enlargement of nucleoids (mtDNA-protein complexes) and activation of cGAS-STING innate immune signalling via mtDNA released into the cytoplasm. However, the relationship among aberrant mitochondria and nucleoid dynamics, mtDNA release and cGAS-STING activation remains unclear. Here we show that, under a variety of mtDNA replication stress conditions and during herpes simplex virus-1 infection, enlarged nucleoids that remain bound to TFAM exit mitochondria. Enlarged nucleoids arise from mtDNA experiencing replication stress, which causes nucleoid clustering via a block in mitochondrial fission at a stage when endoplasmic reticulum actin polymerization would normally commence, defining a fission checkpoint that ensures mtDNA has completed replication and is competent for segregation into daughter mitochondria. Chronic engagement of this checkpoint results in enlarged nucleoids trafficking into early and then late endosomes for disposal. Endosomal rupture during transit through this endosomal pathway ultimately causes mtDNA-mediated cGAS-STING activation. Thus, we propose that replication-incompetent nucleoids are selectively eliminated by an adaptive mitochondria-endosomal quality control pathway that is prone to innate immune system activation, which might represent a therapeutic target to prevent mtDNA-mediated inflammation during viral infection and other pathogenic states.

Effects of immune exhaustion and senescence of innate immunity in autoimmune disorders.

Innate immune system activation is crucial in the inflammatory response, but uncontrolled activation can lead to autoimmune diseases. Cellular exhaustion and senescence are two processes that contribute to innate immune tolerance breakdown. Exhausted immune cells are unable to respond adequately to specific antigens or stimuli, while senescent cells have impaired DNA replication and metabolic changes. These processes can impair immune system function and disrupt homeostasis, leading to the emergence of autoimmunity. However, the influence of innate immune exhaustion and senescence on autoimmune disorders is not well understood. This review aims to describe the current findings on the role of innate immune exhaustion and senescence in autoimmunity, focusing on the cellular and molecular changes involved in each process. Specifically, the article explores the markers and pathways associated with immune exhaustion, such as PD-1 and TIM-3, and senescence, including Β-galactosidase (β-GAL), lamin B1, and p16ink4a, and their impact on autoimmune diseases, namely type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus, and immune-mediated myopathies. Understanding the mechanisms underlying innate immune exhaustion and senescence in autoimmunity may provide insights for the development of novel therapeutic strategies.

Formylated Peptide Receptor-1-Mediated Gut Inflammation as a Therapeutic Target in Inflammatory Bowel Disease.

Formylated peptide receptor (FPR)-1 is a G-coupled receptor that senses foreign bacterial and host-derived mitochondrial formylated peptides (FPs), leading to innate immune system activation. We sought to investigate the role of FPR1-mediated inflammation and its potential as a therapeutic target in inflammatory bowel disease (IBD). We characterized FPR1 gene and protein expression in 8 human IBD (~1000 patients) datasets with analysis on disease subtype, mucosal inflammation, and drug response. We performed in vivo dextran-sulfate sodium (DSS) colitis in C57/BL6 FPR1 knockout mice. In ex vivo studies, we studied the role of mitochondrial FPs and pharmacological blockade of FPR1 using cyclosporin H in human peripheral blood neutrophils. Finally, we assess mitochondrial FPs as a potential mechanistic biomarker in the blood and stools of patients with IBD. Detailed in silico analysis in human intestinal biopsies showed that FPR1 is highly expressed in IBD (n = 207 IBD vs 67 non-IBD controls, P < .001), and highly correlated with gut inflammation in ulcerative colitis (UC) and Crohn's disease (CD) (both P < .001). FPR1 receptor is predominantly expressed in leukocytes, and we showed significantly higher FPR1+ve neutrophils in inflamed gut tissue section in IBD (17 CD and 24 UC; both P < .001). Further analysis in 6 independent IBD (data available under Gene Expression Omnibus accession numbers GSE59071, GSE206285, GSE73661, GSE16879, GSE92415, and GSE235970) showed an association with active gut inflammation and treatment resistance to infliximab, ustekinumab, and vedolizumab. FPR1 gene deletion is protective in murine DSS colitis with lower gut neutrophil inflammation. In the human ex vivo neutrophil system, mitochondrial FP, nicotinamide adenine dinucleotide dehydrogenase subunit-6 (ND6) is a potent activator of neutrophils resulting in higher CD62L shedding, CD63 expression, reactive oxygen species production, and chemotactic capacity; these effects are inhibited by cyclosporin H. We screened for mitochondrial ND6 in IBD (n = 54) using ELISA and detected ND6 in stools with median values of 2.2 gg/mL (interquartile range [IQR] 0.0-4.99; range 0-53.3) but not in blood. Stool ND6 levels, however, were not significantly correlated with paired stool calprotectin, C-reactive protein, and clinical IBD activity. Our data suggest that FPR1-mediated neutrophilic inflammation is a tractable target in IBD; however, further work is required to clarify the clinical utility of mitochondrial FPs as a potential mechanistic marker for future stratification.

Importance of the Frequency at Using Immunomodulatory Therapies with Evidence Based and Standardized Plant Biomodulators

Many years ago, a great deal of research was carried out to improve the suppressed activity of innate immune system in cancer patients using various immunomodulators originated from microorganisms or plants. However, more than 30 years ago these investigations were stopped since their repeated applications often led to a tolerance which could not be explained at the level of science at that time and in spite of a great amount of data, the curative role of innate system was poorly understood. Today, growing evidence suggests that the adaptive cytotoxic T cells have rather prophylactic effects working more proficiently in the early phases of tumor development, whereas the innate cellular system acts more curatively in parallel with disease progression. It’s now also known, that tumor-induced dysregulation of the innate immune system leads to a decreased function of type-1 effector cells and a predominance of type-2 cells, promoting the development of tumors. In this review article a number of results originating from old publications are discussed and presented again in order to interpret them according to our current knowledges which appear to be helpful for more correct application of standardized and evidence based immunomodulators (SEIM) from plant or microbes. Conclusions: 1.) Since the chemistry is not able to produce appropriate structures of Pathogen Associated Molecular Pattern (PAMP) molecules, we need PAMP containing SEIM from plants and microbes which can activate the type-1 phagocytic cells by binding their Pattern Recognition / Toll Like Receptors (RCC/TLR) on their cell membrane. 2.) PAMP molecules have a direct effect only on RCC/TLR molecules of phagocytes and only thereafter with a minimum time delay of 24 hours are the regulatory cascade mechanisms activated which can increase the function of the for the curative tumor defense important MHC-I unrestricted effectors (such as NK, γδT and type-1 NKT cells). 3.) A permanent activation of phagocytic cells can result in a decrease in MHC-1 unrestricted immune function, which may explain the tolerance observed often during continuous SEIM treatments. 4.) Since short-term activations of type-1 phagocytic cells causes more antitumor benefit, on the base of kinetic investigations a necessity to insert of 72h therapy-free intervals during SEIM therapy must be taken into consideration.

Neutrophil extracellular trap-induced intermediate monocytes trigger macrophage activation syndrome in adult-onset Still’s disease

BackgroundAdult-onset Still’s disease (AOSD) is a systemic autoinflammatory disease characterized by innate immune system activation, with a high risk for macrophage activation syndrome (MAS). MAS development is associated with monocyte/macrophage activation and cytokine storm. Monocytes consist of three different subsets, classical monocytes (CMs, CD14brightCD16 −), intermediate monocytes (IMs, CD14brightCD16 +), and non-classical monocytes (NCMs, CD14dimCD16 +), each has distinct roles in inflammatory regulation. However, the frequencies and regulatory mechanism of monocyte subsets in AOSD patients have not been identified.MethodsWe performed flow cytometry, RNA sequencing, phagocytosis analysis, and enzyme-linked immunosorbent assay to evaluate monocyte subsets, cell functions, and potential biomarkers. The effect of neutrophil extracellular traps (NETs) on monocytes was determined by evaluating mRNA levels of DNA sensors, surface CD16 expression, and inflammasome pathway activation.ResultsHigher proportions of intermediate monocytes (IMs) were identified in active AOSD patients. IMs displayed higher expression of CD80, CD86, HLA-DR, and CD163 than CMs and NCMs. CD163 upregulation was noted on AOSD IMs, accompanied by increased phagocytic activity and elevated cytokine/chemokine production, including IL-1β, IL-6, CCL8, and CXCL10. The frequencies of IMs were correlated with disease activity and higher in AOSD patients with MAS (AOSD-MAS). CCL8 and CXCL10 were highly expressed in RNA sequencing of monocytes from AOSD-MAS patients and plasma CXCL10 level could serve as a potential biomarker for AOSD-MAS. Moreover, DNA-sensing pathway was activated in monocytes from AOSD-MAS patients. Stimulation with NETs derived from AOSD induced DNA sensor expression, the expansion of IMs, and inflammasome pathway activation. These effects can be abrogated by DNase I treatment.ConclusionsOur results demonstrated that the proportions of IMs were elevated in AOSD and associated with MAS. The DNA component in NETs from AOSD plays an important role in the formation of IMs, shedding new light for the therapeutic target.

Toll-Like Receptor mRNA Levels in Schizophrenia: Association With Complement Factors and Cingulate Gyrus Cortical Thinning.

Previous studies revealed innate immune system activation in people with schizophrenia (SZ), potentially mediated by endogenous pathogen recognition receptors, notably Toll-like receptors (TLR). TLRs are activated by pathogenic molecules like bacterial lipopolysaccharides (TLR1 and TLR4), viral RNA (TLR3), or both (TLR8). Furthermore, the complement system, another key component of innate immunity, has previously been linked to SZ. Peripheral mRNA levels of TLR1, TLR3, TLR4, and TLR8 were compared between SZ and healthy controls (HC). We investigated their relationship with immune activation through complement expression and cortical thickness of the cingulate gyrus, a region susceptible to immunological hits. TLR mRNA levels and peripheral complement receptor mRNA were extracted from 86 SZ and 77 HC white blood cells; structural MRI scans were conducted on a subset. We found significantly higher TLR4 and TLR8 mRNA levels and lower TLR3 mRNA levels in SZ compared to HC. TLRs and complemental factors were significantly associated in SZ and HC, with the strongest deviations of TLR mRNA levels in the SZ subgroup having elevated complement expression. Cortical thickness of the cingulate gyrus was inversely associated with TLR8 mRNA levels in SZ, and with TLR4 and TLR8 levels in HC. The study underscores the role of innate immune activation in schizophrenia, indicating a coordinated immune response of TLRs and the complement system. Our results suggest there could be more bacterial influence (based on TLR 4 levels) as opposed to viral influence (based on TLR3 levels) in schizophrenia. Specific TLRs were associated with brain cortical thickness reductions of limbic brain structures.

Association between neutrophil to lymphocyte ratio and Alzheimer’s Disease in large biobank cohorts

AbstractBackgroundNeutrophil to lymphocyte ratio (NLR) is used as a marker for systematic inflammation and innate immune system activation; NLR has been associated with Alzheimer’s disease (AD) in previous literature, but mostly in relatively small case control studies. The goal of this study is to investigate the association between AD and NLR in two large biobanks, the UK Biobank and the United States based All of Us.MethodAD was defined using inpatient ICD10/9 codes and death certificates (UK Biobank) or inpatient ICD10/9 codes and Systematized Nomenclature of Medicine (All of Us). Cox proportional hazards models were used to estimate hazard ratios (HR) adjusting for age, sex, race, and recruitment center (UK Biobank). Because the UK Biobank had extensive covariate data available, we also estimated HRs further adjusting for hypertension, hypercholesterolemia, education, body mass index, and smoking.ResultWith complete covariate data, 233,173 UK Biobank (mean age = 58; 56% female; 2,049 incident AD cases) and 68,382 All of Us (mean age = 59; 65% female; 239 incident AD cases) participants were included. In the UK Biobank, every 1 standard deviation (SD) increase in NLR was associated with a 3% increase in AD risk (HR = 1.03, 95% CI = 1.01‐1.05, p‐value = 0.001) and this relationship was robust to lifestyle and clinical factor adjustment. NLR per 1 SD increase was not associated with AD (HR = 1.03, 95% CI = 0.81‐1.17, p‐value = 0.755) in All of Us.ConclusionNLR was associated with AD in UK Biobank but not in All of Us, however, we note that power is lower in All of Us due to fewer AD cases. We plan to repeat this analysis as more cases accrue in All of Us and explore the neutrophil‐associated Duffy null variant for potential modification of this AD/NLR association. These findings provide further evidence for the association between NLR and AD as well as the possible role of systemic inflammation in AD pathology.