Chemokine Responses Research Articles

Prime-Boost Vaccination With Covaxin/BBV152 Induces Heightened Systemic Cytokine and Chemokine Responses.

Covaxin/BBV152 is a whole virion inactivated SARS-CoV-2 vaccine. The effect of prime-boost vaccination with Covaxin on systemic immune responses is not known. We investigated the effect of Covaxin on the plasma levels of a wide panel of cytokines and chemokines at baseline (M0) and at months 1 (M1), 2 (M2) and 3 (M3) following prime-boost vaccination in healthy volunteers. Our results demonstrate that Covaxin induces enhanced plasma levels of Type 1 cytokines (IFNγ, IL-2, TNFα), Type 2/regulatory cytokines (IL-4, IL-5, IL-10 and IL-13), Type 17 cytokine (IL-17A), other pro-inflammatory cytokines (IL-6, IL-12, IL-1α, IL-1β) and other cytokines (IL-3 and IL-7) but diminished plasma levels of IL-25, IL-33, GM-CSF and Type 1 IFNs. Covaxin also induced enhanced plasma levels of CC chemokine (CCL4) and CXC chemokines (CXCL1, CXCL2 and CX3CL1) but diminished levels of CXCL10. Covaxin vaccination induces enhanced cytokine and chemokine responses as early as month 1, following prime-boost vaccination, indicating robust activation of innate and adaptive immune responses in vaccine recipients.

Role of expression of host cytokines in the pathogenesis of H9N2-PB2 reassortant and non-reassortant H5N1 avian influenza viruses isolated from crows in BALB/c mice

The present experiment was conducted to study the role of cytokine, chemokine and TLRs responses of H9N2-PB2 reassortant H5N1 virus as compared to non-reassortant H5N1 virus isolated from crows in BALB/c mice. Two groups (12 mice each) of 6–8 weeks old BALB/c mice were intranasally inoculated with 106 EID50/ml of viruses A/crow/India/03CA04/2015 (H9N2-PB2 reassortant H5N1) and A/crow/India/02CA01/2012 (non-reassortant H5N1). At each interval, brain, lung and spleen were collected and relative quantification of cytokines, chemokines and TLRs was done by qPCR. The H9N2-PB2 reassortant H5N1 infected mice brain, the transcripts of TLR7 were significantly higher than other cytokines at 3dpi and KC was significantly upregulated at 7dpi. In non-reassortant H5N1 infected mice brain showed, TLR 7 and IFNα upregulation at 3dpi and IFNγ and TLR7 upregulation at 7dpi. The H9N2-PB2 reassortant H5N1 infected mice lung revealed, IL2 and TLR7 significant upregulation at 3dpi and in non-reassortant H5N1 infected mice, IL6 was significantly upregulated. At 7dpi in H9N2-PB2 reassortant H5N1 virus infected group mice, IL1 and TLR 3 were significantly upregulated in lungs and in non-reassortant group mice, IL1 and TLR7 were significantly upregulated. At 3dpi in H9N2-PB2 reassortant H5N1 virus infected mice spleen, IL4, IFNα, IFNβ were significantly downregulated and TLR7 transcript was significantly upregulated. In non-reassortant group mice, IL6, IFNα, IFNβ and TLR 3 were significantly upregulated. At 7dpi in H9N2-PB2 reassortant H5N1 virus infected mice spleen, IFNα, IFNβ and TLR7 were significantly lower than other cytokines and in non-reassortant group mice, IFNα and IFNβ were significantly downregulated. This study concludes that dysregulation of cytokines in lungs and brain might have contributed to the pathogenesis of both the viruses in mice.

PSXIV-20 Ovine circulatory markers regulating the acute-phase response of variable stress responding sheep to LPS challenge

Abstract Pathogens induce neuroendocrine-immune interactions in their hosts, which are a basis to overcome the microbial stressor. These interactions result in individual variation of the hypothalamic-pituitary-adrenal (HPA) axis response and could contribute to variable stress resiliency. In present study, a comprehensive set of circulatory markers was assessed in variable stress responding lambs selected from a population (n = 112) and categorized based on cortisol levels as high (HSR, 336.2 ±27.9 nmol/L, n =12), middle (MSR, 147.3 ±9.5 nmol/L, n =12) and low (LSR, 32.1 ±10.4 nmol/L, n =12) responding phenotypes post LPS challenge (400 ng/kg iv). Blood was collected from the jugular vein at 0 (pre-) and 4 hrs post-LPS challenge to monitor changes in serum with a panel of 15 pro- and anti-inflammatory cytokines and chemokines and 84 miRNAs, and white blood cell (WBC) populations. The HSR had the strongest fever and pro-inflammatory IL-6, IFN-γ cytokine responses compared to MSR and LSR. HSR and MSR had stronger anti-inflammatory IL-10 cytokine and CCL2 chemokine responses than LSR. WBC counts changed between 0 and 4 hrs; however, no differences were detected among the variable stress response groups. Three miRNAs, oar-miR-485-5p (+3.82 folds), oar-miR-1193-5p (+2.43 folds) and oar-miR-3957-5p (+3.14 folds) were significantly (P < 0.05) upregulated, and seven miRNAs, oar-miR-376b-3p (-6.6 fold), oar-miR-376c-3p (3.5 folds), oar-miR-411b-5p (-11.69 folds), (oar-miR-376a-3p (-2.28 fold), oar-miR-376b-3p (-6.08 folds), oar-miR-376c-3p (-2.62 folds), oar-miR-381-3p (-3.85 folds) were downregulated (P < 0.05) in HSR compared to LSR and MSR. Functional analysis of miRNAs revealed their roles in activating TGF-beta signalling, Cytokine receptor interaction and Thyroid signalling pathways in HSR phenotypes indicating a hyper-induced acute-phase response. In summary, these results indicate variation in the acute-phase response to stress, and some of these markers could be used as stress biomarkers. Further investigation is warranted to understand the plausible association of cortisol phenotype with other important traits.

The link between serum ACKR2 level and Crohn's Disease and its activity

Backgrounds/Aim: Atypical chemokine receptor (ACKR) family suppresses chemokine response and keeps the inflammatory state under control. This study investigated ACKR2 serum levels, which are thought to have an effect on the extreme inflammatory state in Crohn's disease (CD). Methods: Active and newly diagnosed Crohn's patients under treatment and a healthy control group were included in this prospective case-control study. Patients under the age of 18 years and those with Crohn's disease in remission were excluded. Clinical, demographic, laboratory parameters and serum ACKR2 levels of the patients were examined. Disease activity was evaluated using the simplified endoscopic score for Crohn’s disease (SES-CD) and Crohn’s disease activity index (CDAI) index. The relationship between disease activity and serum ACKR2 was evaluated using the Spearman correlation analysis. Results: A total of 119 subjects (66 CD patients and 53 healthy controls) were included in the study. Serum ACKR2 level was significantly lower in the CD group (4.80 ng/mL) compared to the control group (11.15 ng/mL) (P

Systematic investigation of cytokine signaling activity at the tissue and single-cell levels.

Cytokines are critical for intercellular communication in human health and disease, but the investigation of cytokine signaling activity has remained challenging due to the short half-lives of cytokines and the complexity/redundancy of cytokine functions. To address these challenges, we developed the Cytokine Signaling Analyzer (CytoSig, https://cytosig.ccr.cancer.gov), providing both a database of target genes modulated by cytokines and a predictive model of cytokine signaling cascades from transcriptomic profiles. We collected 20,591 transcriptome profiles for human cytokine, chemokine, and growth factor responses. This atlas of transcriptional patterns induced by cytokines enabled the reliable prediction of signaling activities in distinct cell populations in infectious diseases, chronic inflammation, and cancer using bulk and single-cell transcriptomic data. CytoSig revealed previously unidentified roles of many cytokines, such as BMP6 as an anti-inflammatory factor, and identified candidate therapeutic targets in human inflammatory diseases, such as CXCL8 for severe COVID-19.

A high-throughput customized cytokinome screen of colon cancer cell responses to small-molecule oncology drugs.

Inflammatory cytokines, chemokines, and growth factors are molecular messengers that circulate and have the capability to modify the tumor microenvironment and impact therapeutic response. The characterization of soluble mediators as biomarkers for diagnosis and prognosis is of interest in oncology. We utilize the cytokinome to characterize the response of colorectal tumor cell lines to selected small-molecules in oncology as a proof-of-concept dataset with immunomodulatory analyte heat map rankings for drug and cell line combinations. We observed overall trends in drug class effects with MEK-, BRAF-, PARP-inhibitors, and Imipridones in cytokine, chemokine, and growth factor responses that may help guide therapy selection. MEK-inhibitor treatment downregulated analytes VEGF, CXCL9/MIG, and IL-8/CXCL8 and upregulated CXCL14/BRAK, Prolactin, and CCL5/RANTES. BRAF-inhibitor treatment downregulated VEGF and IL-8/CXCL8, while increasing soluble TRAIL-R2. Treatment with PARP-inhibitors decreased CXCL9/MIG, IL-8/CXCL8, CCL3/MIP-1 alpha, VEGF, and CXCL14/BRAK, while treatment increased soluble TRAIL-R2 and prolactin. Treatment with Imipridones decreased CCL3/MIP-1 alpha, VEGF, CXCL14/BRAK, IL-8/CXCL8, and Prolactin and increased CXCL5/ENA-78. We also observed differential responses to therapeutics depending on the mutational profile of the cell line. In the future, a similar but larger dataset may be utilized in the clinic to aid in the prediction of patient response to immunomodulatory therapies based on tumor genotype.

Cytokine and Chemokine Responses in Invasive Aspergillosis Following Hematopoietic Stem Cell Transplantation: Past Evidence for Future Therapy of Aspergillosis

Invasive pulmonary aspergillosis is a frequent complication in immunocompromised individuals, and it continues to be an important cause of mortality in patients undergoing hematopoietic stem cell transplantation. In addition to antifungal therapy used for mycoses, immune-modulatory molecules such as cytokines and chemokines can modify the host immune response and exhibit a promising form of antimicrobial therapeutics to combat invasive fungal diseases. Cytokine and chemokine profiles may also be applied as biomarkers during fungal infections and clinical research has demonstrated different activation patterns of cytokines in invasive mycoses such as aspergillosis. In this review, we summarize different aspects of cytokines that have been described to date and provide possible future directions in research on invasive pulmonary aspergillosis following hematopoietic stem cell transplantation. These findings suggest that cytokines and chemokines may serve as useful biomarkers to improve diagnosis and monitoring of infection.

Increased plasma levels of CCL20 in peripheral blood of rheumatoid arthritis patients and its association with clinical and laboratory parameters.

Rheumatoid arthritis (RA) is a systemic autoimmune disease that primarily affects small joints. The impaired chemokine and cytokine responses are essential pathological mechanisms for the RA clinical presentation. Given the role of chemokines and inflammatory reactions in RA pathogenesis, we evaluate the association between the plasma concentration of CCL20 with the clinical and laboratory parameters in newly diagnosed RA patients. Forty-five newly diagnosed RA patients and forty-five healthy subjects were enrolled in this study. The plasma levels of CCL20, rheumatoid factor, and anti-citrullinated peptide antibodies were measured using the enzyme-linked immunosorbent assay (ELISA) technique. The plasma levels of CCL20 were increased significantly in RA patients compared to the healthy controls (p < 0.0001). There was a positive correlation between CCL20 and RF, anti-CCP, ESR, and DAS-28 (p < 0.0001, r = 0.669; p < 0.015, r = 0.358; p < 0.0001, r = 0.586; p < 0.0001, r = 0.769). The increased plasma levels of CCL20 in newly diagnosed RA patients may contribute to RA pathogenesis, and it is in association with clinical and laboratory parameters. Key Points • CCL20 has a contribution to the early phase of RA.

Bovine innate immune phenotyping via a standardized whole blood stimulation assay

Cattle vary in their susceptibility to infection and immunopathology, but our ability to measure and longitudinally profile immune response variation is limited by the lack of standardized immune phenotyping assays for high-throughput analysis. Here we report longitudinal innate immune response profiles in cattle using a low-blood volume, whole blood stimulation system—the ImmunoChek (IChek) assay. By minimizing cell manipulation, our standardized system minimizes the potential for artefactual results and enables repeatable temporal comparative analysis in cattle. IChek successfully captured biological variation in innate cytokine (IL-1β and IL-6) and chemokine (IL-8) responses to 24-hr stimulation with either Gram-negative (LPS), Gram-positive (PamCSK4) bacterial or viral (R848) pathogen-associated molecular patterns (PAMPs) across a 4-month time window. Significant and repeatable patterns of inter-individual variation in cytokine and chemokine responses, as well as consistent high innate immune responder individuals were identified at both baseline and induced levels. Correlation coefficients between immune response read-outs (IL-1β, IL-6 and IL-8) varied according to PAMP. Strong significant positive correlations were observed between circulating monocytes and IL-6 levels for null and induced responses (0.49–0.61) and between neutrophils and cytokine responses to R848 (0.38–0.47). The standardized assay facilitates high-throughput bovine innate immune response profiling to identify phenotypes associated with disease susceptibility and responses to vaccination.

Siglec-H-Deficient Mice Show Enhanced Type I IFN Responses, but Do Not Develop Autoimmunity After Influenza or LCMV Infections.

Siglec-H is a DAP12-associated receptor on plasmacytoid dendritic cells (pDCs) and microglia. Siglec-H inhibits TLR9-induced IFN-α production by pDCs. Previously, it was found that Siglec-H-deficient mice develop a lupus-like severe autoimmune disease after persistent murine cytomegalovirus (mCMV) infection. This was due to enhanced type I interferon responses, including IFN-α. Here we examined, whether other virus infections can also induce autoimmunity in Siglec-H-deficient mice. To this end we infected Siglec-H-deficient mice with influenza virus or with Lymphocytic Choriomeningitis virus (LCMV) clone 13. With both types of viruses we did not observe induction of autoimmune disease in Siglec-H-deficient mice. This can be explained by the fact that both types of viruses are ssRNA viruses that engage TLR7, rather than TLR9. Also, Influenza causes an acute infection that is rapidly cleared and the chronicity of LCMV clone 13 may not be sufficient and may rather suppress pDC functions. Siglec-H inhibited exclusively TLR-9 driven type I interferon responses, but did not affect type II or type III interferon production by pDCs. Siglec-H-deficient pDCs showed impaired Hck expression, which is a Src-family kinase expressed in myeloid cells, and downmodulation of the chemokine receptor CCR9, that has important functions for pDCs. Accordingly, Siglec-H-deficient pDCs showed impaired migration towards the CCR9 ligand CCL25. Furthermore, autoimmune-related genes such as Klk1 and DNase1l3 are downregulated in Siglec-H-deficient pDCs as well. From these findings we conclude that Siglec-H controls TLR-9-dependent, but not TLR-7 dependent inflammatory responses after virus infections and regulates chemokine responsiveness of pDCs.

Downregulated ARID1A by miR-185 Is Associated With Poor Prognosis and Adverse Outcomes in Colon Adenocarcinoma.

AT-rich interaction domain 1A (ARID1A) is a tumor suppressor gene that mutates in several cancer types, including breast cancer, ovarian cancer, and colorectal cancer (CRC). In colon adenocarcinoma (COAD), the low expression of ARID1A was reported but the molecular reason is unclear. We noticed that ARID1A low expression was associated with increased levels of miR-185 in the COAD. Therefore, this study aims to explore ncRNA-dependent mechanism that regulates ARID1A expression in COAD regarding miR-185. The expression of ARID1A was tested in COAD cell line under the effect of miR-185 mimics compared with inhibitor. The molecular features associated with loss of ARID1A and its association with tumor prognosis were analyzed using multi-platform data from The Cancer Genome Atlas (TCGA), and gene set enrichment analysis (GSEA) to identify potential signaling pathways associated with ARID1A alterations in colon cancer. Kaplan-Meier survival curve showed that a low level of ARID1A was closely related to low survival rate in patients with COAD. Results showed that inhibiting miR-185 expression in the COAD cell line significantly restored the expression of ARID1A. Further, the increased expression of ARID1A significantly improved the prolonged overall survival of COAD. We noticed that there is a possible relationship between ARID1A high expression and tumor microenvironment infiltrating immune cells. Furthermore, the increase of ARID1A in tumor cells enhanced the response of inflammatory chemokines. In conclusion, this study demonstrates that ARID1A is a direct target of miR-185 in COAD that regulates the immune modulations in the microenvironment of COAD.

Development of a Human Intestinal Organoid Model for In Vitro Studies on Gut Inflammation and Fibrosis.

Inflammatory Bowel Diseases (IBDs) are characterized by chronic intestinal inflammation and fibrosis, the latter being the predominant denominator for long-term complications. Epithelial and mesenchymal 2D cultures are highly utilized in vitro models for the preclinical evaluation of anti-inflammatory and antifibrotic therapies. More recently, human intestinal organoids (HIOs), a new 3D in vitro model derived from pluripotent stem cells, have the advantage to closely resemble the architecture of the intestinal mucosa. However, the appropriate timing for the study of inflammatory and fibrotic responses, during HIO development, has not been adequately investigated. We developed HIOs from the human embryonic stem cell line, H1, and examined the expression of mesenchymal markers during their maturation process. We also investigated the effect of inflammatory stimuli on the expression of fibrotic and immunological mediators. Serial evaluation of the expression of mesenchymal and extracellular matrix (ECM) markers revealed that HIOs have an adequately developed mesenchymal component, which gradually declines through culture passages. Specifically, CD90, collagen type I, collagen type III, and fibronectin were highly expressed in early passages but gradually diminished in late passages. The proinflammatory cytokines IL-1α and TNF-α induced the mRNA expression of fibronectin, collagen types I and III, tissue factor (TF), and alpha-smooth muscle actin (α-SMA) primarily in early passages. Similarly, HIOs elicited strong mRNA and protein mesenchymal (CXCL10) and epithelial (CXCL1, CCL2, CXCL8, and CCL20) chemokine responses in early but not late passages. In contrast, the epithelial tight junction components, CLDN1 and JAMA, responded to inflammatory stimulation independently of the culture passage. Our findings indicate that this HIO model contains a functional mesenchymal component, during early passages, and underline the significance of the mesenchymal cells' fitness in inflammatory and fibrotic responses. Therefore, we propose that this model is suitable for the study of epithelial-mesenchymal interactions in early passages when the mesenchymal component is active.

Endotoxin-induced cytokine, chemokine and white blood cell profiles of variable stress-responding sheep

Individual variation of the hypothalamic-pituitary-adrenal (HPA) axis response to stress could contribute to variable stress resiliency of livestock. During stress events, the innate immune system can also become activated and work in concert with the neuroendocrine system to restore homeostasis, while minimizing tissue damage. The purpose of this study was to assess immune function in variable stress-responding sheep in response to bacterial lipopolysaccharide (LPS) endotoxin immune-challenge. High (HSR, n = 12), middle (MSR, n = 12), and low-stress responders (LSR, n = 12) were selected from a population of 112 female lambs and classified based on serum cortisol concentration after receiving an intravenous bolus of LPS (400 ng/kg). Blood was collected from the jugular vein at 0 and 4 hrs post-LPS challenge to monitor changes in serum pro- and anti-inflammatory cytokines and chemokines, and white blood cell populations. Rectal temperature was recorded hourly to monitor fever. HSR had the greatest increase in rectal temperature and strongest pro-inflammatory IL-6 and IFN-γ cytokine responses compared to MSR and LSR. HSR and MSR had stronger anti-inflammatory IL-10 cytokine and CCL2 chemokine responses than LSR. White blood cell counts changed between 0 and 4 h; however, no differences were detected among the variable stress response groups. The distinct inflammatory response in variable stress responding sheep could contribute to individual differences in stress resiliency and this warrants investigation in the context of other types of stress.

Systemic IL-15, IFN-γ, and IP-10/CXCL10 signature associated with effective immune response to SARS-CoV-2 in BNT162b2 mRNA vaccine recipients

Early responses to vaccination are important for shaping both humoral and cellular protective immunity. Dissecting innate vaccine signatures may predict immunogenicity to help optimize the efficacy of mRNA and other vaccine strategies. Here, we characterize the cytokine and chemokine responses to the 1st and 2nd dose of the BNT162b2 mRNA (Pfizer/BioNtech) vaccine in antigen-naive and in previously coronavirus disease 2019 (COVID-19)-infected individuals (NCT04743388). Transient increases in interleukin-15 (IL-15) and interferon gamma (IFN-γ) levels early after boost correlate with Spike antibody levels, supporting their use as biomarkers of effective humoral immunity development in response to vaccination. We identify a systemic signature including increases in IL-15, IFN-γ, and IP-10/CXCL10 after the 1st vaccination, which were enriched by tumor necrosis factor alpha (TNF-α) and IL-6 after the 2nd vaccination. In previously COVID-19-infected individuals, a single vaccination results in both strong cytokine induction and antibody titers similar to the ones observed upon booster vaccination in antigen-naive individuals, a result with potential implication for future public health recommendations.

COVID-19, T Cells, Cytokines and Immunotherapy: Review

In December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus (COVID-19), materialized in the city of Wuhan and quickly spread to form a global pandemic. An essential role in the immune system is undertaken by lymphocytes, which defend against bacteria, viruses, fungi, and parasites. Previous study found that very severe COVID-19 patients had suppression of the immune response enabling the virus to spread and cause more damage. This was evident by the changes in their white blood cell and lymphocyte count. Early clinical findings suggest that those suffering from severe COVID-19 have reduced numbers of lymphocytes, monocytes, and other granulocytes. One of the most efficient responses for a variety of viral infections is cellular immune response activation, especially via T cells. Viruses can be eliminated by T cytotoxic (CD8+) (Tc) in the host body, these secrete a variety of molecules, including interferons (IFNs), granzyme, and perforin. T helper (CD4+) (Th) cells help by assisting cytotoxic T cells and B cells to eliminate viral infection. CD8+ and CD4+ work together in a coordinated immune response with other constituents to primarily resolve acute viral infections, and after to produce protection against any reinfection.&#x0D; Also, COVID-19 causes dramatic changes in cytokine profiles and serological markers. Therefore, the subsets of immune cells and the level of the pro-inflammatory cytokines are crucial evidence to determine the severity of COVID-19. The disease severity has already been proved to be associated with the disruption in the proinflammatory chemokine response, this eventually leads to a cytokine storm and progression of cytokines release syndrome (CRS). This review aimed to demonstrate a full understanding of the alterations to the immune response by determining the T-cell expression and cytokine levels against the pathological processes of COVID-19, which can be a significant step in early treatment and diagnosis of this disease, in reduction of COVID-19 mortality cases, and to emphasize the most recent and current studies to try to identify new immuno-therapeutics for COVID-19.

Abstract 700: CellSig: A data-driven model of cytokine activity identifies therapeutic targets for severe COVID-19 and cancer immunotherapy-induced colitis

Abstract Studies of cytokine activity are foundational to immunology research. However, the complexity and redundancy of cytokine functions have prevented systematic profiling of signaling activities in biological samples. To address these issues, we developed Cell Signaling Analyzer (CellSig, https://cellsig.ccr.cancer.gov), a data-driven infrastructure to model how cytokines cooperate with and antagonize each other in inflammation processes. We manually curated 20,591 transcriptomic profiles related to human cytokine, chemokine, and growth-factor response. CellSig revealed two main cytokine groups typified by NFKB and interferon-associated signals, respectively. The primary pro-inflammatory members of each group induce a distinct set of secondary signals and are repressed by different anti-inflammatory cytokines. CellSig can reliably predict target activities of 43 cytokines using the transcriptomic data from severe COVID-19 cases, cancer immunotherapy-induced colitis, and immune checkpoint blockade response. Among these clinical applications, the differential activities of the NFKB and interferon cytokine groups revealed potential therapeutic targets for alleviating adverse inflammation without compromising viral clearance or cancer treatment. Citation Format: Peng Jiang, Yu Zhang, Beibei Ru, Eytan Ruppin, Kai Wucherpfennig. CellSig: A data-driven model of cytokine activity identifies therapeutic targets for severe COVID-19 and cancer immunotherapy-induced colitis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 700.

Human variation in gingival inflammation.

Oral commensal bacteria actively participate with gingival tissue to maintain healthy neutrophil surveillance and normal tissue and bone turnover processes. Disruption of this homeostatic host-bacteria relationship occurs during experimental gingivitis studies where it has been clearly established that increases in the bacterial burden increase gingival inflammation. Here, we show that experimental gingivitis resulted in three unique clinical inflammatory phenotypes (high, low, and slow) and reveal that interleukin-1β, a reported major gingivitis-associated inflammatory mediator, was not associated with clinical gingival inflammation in the slow response group. In addition, significantly higher levels of Streptococcus spp. were also unique to this group. The low clinical response group was characterized by low concentrations of host mediators, despite similar bacterial accumulation and compositional characteristics as the high clinical response group. Neutrophil and bone activation modulators were down-regulated in all response groups, revealing novel tissue and bone protective responses during gingival inflammation. These alterations in chemokine and microbial composition responses during experimental gingivitis reveal a previously uncharacterized variation in the human host response to a disruption in gingival homeostasis. Understanding this human variation in gingival inflammation may facilitate the identification of periodontitis-susceptible individuals. Overall, this study underscores the variability in host responses in the human population arising from variations in host immune profiles (low responders) and microbial community maturation (slow responders) that may impact clinical outcomes in terms of destructive inflammation.

Acute systemic inflammation exacerbates neuroinflammation in Alzheimer's disease: IL-1β drives amplified responses in primed astrocytes and neuronal network dysfunction.

Neuroinflammation contributes to Alzheimer's disease (AD) progression. Secondary inflammatory insults trigger delirium and can accelerate cognitive decline. Individual cellular contributors to this vulnerability require elucidation. Using APP/PS1 mice and AD brain, we studied secondary inflammatory insults to investigate hypersensitive responses in microglia, astrocytes, neurons, and human brain tissue. The NLRP3 inflammasome was assembled surrounding amyloid beta, and microglia were primed, facilitating exaggerated interleukin-1β(IL-1β) responses to subsequent LPS stimulation. Astrocytes were primed to produce exaggerated chemokine responses to intrahippocampal IL-1β. Systemic LPS triggered microglial IL-1β, astrocytic chemokines, IL-6, and acute cognitive dysfunction, whereas IL-1β disrupted hippocampal gamma rhythm, all selectively in APP/PS1 mice. Brains from AD patients with infection showed elevated IL-1β and IL-6 levels. Therefore, amyloid leaves the brain vulnerable to secondary inflammation at microglial, astrocytic, neuronal, and cognitive levels, and infection amplifies neuroinflammatory cytokine synthesis in humans. Exacerbation of neuroinflammation to produce deleterious outcomes like delirium and accelerated disease progression merits careful investigation in humans.

Platelet-Derived Growth Factor-D Activates Complement System to Propagate Macrophage Polarization and Neovascularization.

Platelet-derived growth factor-D (PDGF-D) is highly expressed in immune cells. However, the potential role of PDGF-D in immune system remains thus far unclear. Here, we reveal a novel function of PDGF-D in activating both classical and alternative complement pathways that markedly increase chemokine and cytokine responses to promote macrophage polarization. Pharmacological targeting of the complement C3a receptor using SB290157 alleviated PDGF-D-induced neuroinflammation by blocking macrophage polarization and inhibited pathological choroidal neovascularization. Our study thus suggests that therapeutic strategies targeting both PDGF-D and the complement system may open up new possibilities for the treatment of neovascular diseases.

P045 Oncostatin M induces strong fibrotic and chemokine responses from primary colonic subepithelial myofibroblasts

Abstract Background Oncostatin M (OSM) may play an important role in Inflammatory Bowel Disease (IBD) pathogenesis. Specifically, both OSM and its receptor are upregulated in inflamed colonic regions of IBD patients, and high OSM expression has been associated with failure to respond to anti-TNF therapy. Our aim was to investigate the effect of OSM in fibrotic factors and chemokine expression on primary colonic subepithelial myofibroblasts (SEMFs) from healthy individuals (HI). Methods Primary SEMFs were isolated from endoscopically-obtained colonic biopsies from HI. SEMFs were stimulated with 1, 10, or 100ng/ml OSM for 6 hours, with or without pre-stimulation with 5ng/ml IL-1α plus 50ng/ml TNF-α for 24h. Total RNA was collected and mRNA transcripts for collagen type I, type III, fibronectin, and the chemokines CCL2, CXCL9, CXCL10 and CXCL11 were measured by reverse transcription quantitative PCR. Results Unstimulated SEMFs had a basal expression of collagen type I, III, fibronectin, CCL2, CXCL9, CXCL10 and CXCL11. OSM stimulation augmented chemokine mRNA expression in a dose-dependent manner (Table 1) but had no effect on fibrotic factors expression. Pre-stimulation of myofibroblasts with TNF-α and IL-1α resulted in augmented expression of collagens I and III and fibronectin, in addition to further increases in chemokine expression in response to subsequent stimulation by OSM (Table 2). Conclusion Our results show that stimulation with OSM induces fibrotic and chemokine responses by SEMFs. Our findings further support the hypothesis that SEMFs may play a key role in regulating chronic intestinal inflammation and response to biological therapy.