TNF Secretion Research Articles

Patients with coronary atherosclerosis had an altered ratio of monocyte subpopulations in the blood, which was associated with an inflammatory cell response

Coronary artery disease (CAD) is one of the leading causes of death in developed countries. Experimental data confirm the role of monocytes in the development of CAD. Three main subpopulations of circulating blood monocytes are known: classical CD14++CD16- (~80%), intermediate CD14+CD16+ (~5%) and non-classical CD14+CD16++(~15%). It is believed that each of the subpopulations of monocytes performs different functions. There are studies that demonstrate that classical monocytes respond more to the bacterial presence, whereas non-classical ones respond to the viral one. However, the functions of monocyte subpopulations have not been fully studied. Previously, we demonstrated that circulating monocytes of the blood of patients with atherosclerosis had increased proinflammatory activity. We decided to find out how the ratio of monocyte subpopulations in the blood is related to the inflammatory response of cells in atherosclerosis. The aim of our work was to investigate the relationship of the inflammatory response of primary monocytes with the distribution of monocyte subpopulations relative to the total pool of monocytes in healthy and sick CAD. The study included 20 men aged 46 to 70 years, 10 of them without CAD and 10 patients with CAD. A coronary angiography was performed, according to the results of which the patients were divided into patients with coronary atherosclerosis with detected stenosis in 2 or more arteries (CAD) and healthy ones without stenosis in the arteries. Next, blood was taken to study circulating monocytes. Monocyte subpopulations were detected by flow cytometry from the leukocyte fraction using antibodies against CD14- FITC and CD16-PB450-A. Immediately after isolation, monocytes were stimulated with LPS with a final concentration of 1 ug/mL, and a supernatant was selected 24 hours later for further enzyme immunoassay. The inflammatory response was assessed by the secretion of cytokines TNFα, IL-1β, IL-6, IL-8, IL-10, and CCL2 using ELISA. The monocytes of CAD patients had an altered inflammatory response in response to LPS stimulation compared to patients without CAD. This was manifested in increased secretion of IL-1β and TNF, and decreased secretion of CCL2 and IL-6. An increase in the number of intermediate and non-classical monocytes in patients with CAD was associated with changes in the inflammatory response of cells to the secretion of cytokines IL-1β and CCL2. It can be assumed that pathological changes in the representation of monocyte subpopulations in the bloodstream may be one of the causes of chronic inflammation in the walls of the arteries, contributing to the progression of atherosclerotic lesions.

Ageing results in an exacerbated inflammatory response to LPS by resident lung cells

BackgroundAgeing is associated with an increased risk of lung infection and chronic inflammatory lung disease. Innate immune responses are the first line of defence in the respiratory tract, however, age-related changes to innate immunity in the lung are not fully described. Both resident haematopoietic cells, such as alveolar macrophages, and non-haematopoeitic cells, such as epithelial and endothelial cells can contribute to inflammatory and immune responses in the lung. In this study we aimed to determine the impact of ageing on early innate responses of resident cells in the lung.ResultsAged and young mice were inoculated intranasally with lipopolysaccharide (LPS). After 4 h, aged mice recruited higher numbers of neutrophils to the airways and lung. This exacerbated inflammatory response was associated with higher concentrations of chemokines CXCL1, CXCL2 and CCL2 in the airways. Next, precision cut lung slices (PCLS) were stimulated ex vivo with LPS for 16 h. Gene expression of Cxcl2, Tnf and Il1b were all higher in PCLS from aged than young mice and higher levels of secretion of CXCL2 and TNF were detected. To determine which lung cells were altered by age, LPS was intranasally administered to aged and young mice and individual populations of cells isolated by FACS. RT-PCR on sorted cell populations demonstrated higher expression of inflammatory cytokines Cxcl2, Ccl2 and Tnf in epithelial cells and alveolar macrophages and higher expression of Cxcl2 by endothelial cells of aged mice compared to young. These differences in expression of pro-inflammatory cytokines did not correspond to higher levels of Tlr4 expression.ConclusionsAgeing leads to a heightened neutrophilic inflammatory response in the lung after LPS exposure, and higher expression and production of pro-inflammatory cytokines by resident lung cells, including alveolar macrophages, epithelial cells and endothelial cells. The responses of multiple resident lung cell populations are altered by aging and contribute to the exacerbated inflammation in the lung following LPS challenge. This has implications for our understanding of respiratory infections and inflammation in older people.

Differential signalling requirements for RIPK1-dependent pyroptosis in neutrophils and macrophages

TLR4 and TNFR1 signalling promotes potent proinflammatory signal transduction events, thus, are often hijacked by pathogenic microorganisms. We recently reported that myeloid cells retaliate Yersinia blockade of TAK1/IKK signalling by triggering RIPK1-dependent caspase-8 activation that promotes downstream GSDMD and GSDME-mediated pyroptosis in macrophages and neutrophils respectively. However, the upstream signalling events for RIPK1 activation in these cells are not well defined. Here, we demonstrate that unlike in macrophages, RIPK1-driven pyroptosis and cytokine priming in neutrophils are driven through TNFR1 signalling, while TLR4-TRIF signalling is dispensable. Furthermore, we demonstrate that activation of RIPK1-dependent pyroptosis in neutrophils during Yersinia infection requires IFN-γ priming, which serves to induce surface TNFR1 expression and amplify soluble TNF secretion. In contrast, macrophages utilise both TNFR1 and TLR4-TRIF signalling to trigger cell death, but only require TRIF but not autocrine TNFR1 for cytokine production. Together, these data highlight the emerging theme of cell type-specific regulation in cell death and immune signalling in myeloid cells.

TLR9-Dependent Activation by Inactivated Parapoxvirus Ovis in Murine Bone Marrow-Derived Dendritic Cells Is Associated with Specific Strain-Dependent Dendritic Cell Subsets

Introduction: Inactivated parapoxvirus ovis (iPPVO) exerts strong immunomodulatory effects on innate immune cells, making it an attractive therapeutic candidate. However, little is known about the signaling pathways that are involved in iPPVO-induced immune responses. Methods: In this study, we systematically analyzed how different types of dendritic cells (DCs) react to iPPVO (Zylexis, strain D1701) in both BALB/c and C57BL/6 mice by flow cytometry and ELISAs, and investigated which signaling pathway is related to DC activation by Western blotting and protein profiling. Results: We demonstrated that bone marrow-derived conventional DCs (BM-cDCs) and bone marrow-derived plasmacytoid DCs (BM-pDCs) matured and secreted type I interferons in response to Zylexis stimulation in both mouse strains. Similarly, Zylexis promoted the secretion of IL-12/23p40 and TNF by pDCs. However, IL-12/23p40 and TNF secretion by cDCs were induced in BALB/c mice but not in C57BL/6 mice. Analyzing the underlying signaling pathways revealed that iPPVO-induced maturation of cDCs was Toll-like receptor 9 (TLR9) independent, while the maturation of pDCs partially depended on the TLR9 pathway. Moreover, the production of proinflammatory cytokines by cDCs and the secretion of IFN-α/β by pDCs partially depended on the TLR9 pathway in both mouse strains. Therefore, other signaling pathways seem to participate in the response of DCs to iPPVO, supported by protein profiling. Conclusion: Our data provide useful insights into the diversity of iPPVO sensors and their varying effects across different strains and species.

Rv2231c, a unique histidinol phosphate aminotransferase from Mycobacterium tuberculosis, supports virulence by inhibiting host-directed defense

Nitrogen metabolism of M. tuberculosis is critical for its survival in infected host cells. M. tuberculosis has evolved sophisticated strategies to switch between de novo synthesis and uptake of various amino acids from host cells for metabolic demands. Pyridoxal phosphate-dependent histidinol phosphate aminotransferase-HspAT enzyme is critically required for histidine biosynthesis. HspAT is involved in metabolic synthesis of histidine, phenylalanine, tyrosine, tryptophan, and novobiocin. We showed that M. tuberculosis Rv2231c is a conserved enzyme with HspAT activity. Rv2231c is a monomeric globular protein that contains α-helices and β-sheets. It is a secretory and cell wall-localized protein that regulates critical pathogenic attributes. Rv2231c enhances the survival and virulence of recombinant M. smegmatis in infected RAW264.7 macrophage cells. Rv2231c is recognized by the TLR4 innate immune receptor and modulates the host immune response by suppressing the secretion of the antibacterial pro-inflammatory cytokines TNF, IL-12, and IL-6. It also inhibits the expression of co-stimulatory molecules CD80 and CD86 along with antigen presenting molecule MHC-I on macrophage and suppresses reactive nitrogen species formation, thereby promoting M2 macrophage polarization. Recombinant M. smegmatis expressing Rv2231c inhibited apoptosis in macrophages, promoting efficient bacterial survival and proliferation, thereby increasing virulence. Our results indicate that Rv2231c is a moonlighting protein that regulates multiple functions of M. tuberculosis pathophysiology to increase its virulence. These mechanistic insights can be used to better understand the pathogenesis of M. tuberculosis and to design strategies for tuberculosis mitigation.

Induction of NK cell reactivity against acute myeloid leukemia by Fc-optimized CD276 (B7-H3) antibody.

Acute myeloid leukemia (AML) remains a therapeutic challenge despite recent therapeutic advances. Although monoclonal antibodies (mAbs) engaging natural killer (NK) cells via antibody-dependent cellular cytotoxicity (ADCC) hold promise in cancer therapy, almost none have received clinical approval for AML, so far. Recently, CD276 (B7-H3) has emerged as a promising target for AML immunotherapy, due to its high expression on leukemic blasts of AML patients. Here, we present the preclinical development of the Fc-optimized CD276 mAb 8H8_SDIE with enhanced CD16 affinity. We demonstrate that 8H8_SDIE specifically binds to CD276 on AML cell lines and primary AML cells and induces pronounced NK cell activation and degranulation as measured by CD69, CD25, and CD107a. Secretion of IFNγ, TNF, granzyme B, granulysin, and perforin, which mediate NK cell effector functions, was induced by 8H8_SDIE. A pronounced target cell-restricted lysis of AML cell lines and primary AML cells was observed in cytotoxicity assays using 8H8_SDIE. Finally, xenograft models with 8H8_SDIE did not cause off-target immune activation and effectively inhibited leukemia growth in vivo. We here present a novel attractive immunotherapeutic compound that potently induces anti-leukemic NK cell reactivity in vitro and in vivo as treatment option for AML.

Trypanosoma cruzi killing and immune response boosting by novel phenoxyhydrazine-thiazole against Chagas disease

Trypanosoma cruzi (T. cruzi) causes Chagas, which is a neglected tropical disease (NTD). WHO estimates that 6 to 7 million people are infected worldwide. Current treatment is done with benznidazole (BZN), which is very toxic and effective only in the acute phase of the disease. In this work, we designed, synthesized, and characterized thirteen new phenoxyhydrazine-thiazole compounds and applied molecular docking and in vitro methods to investigate cell cytotoxicity, trypanocide activity, nitric oxide (NO) production, cell death, and immunomodulation. We observed a higher predicted affinity of the compounds for the squalene synthase and 14-alpha demethylase enzymes of T. cruzi. Moreover, the compounds displayed a higher predicted affinity for human TLR2 and TLR4, were mildly toxic in vitro for most mammalian cell types tested, and LIZ531 (IC50 2.8 μM) was highly toxic for epimastigotes, LIZ311 (IC50 8.6 μM) for trypomastigotes, and LIZ331 (IC50 1.9 μM) for amastigotes. We observed that LIZ311 (IC50 2.5 μM), LIZ431 (IC50 4.1 μM) and LIZ531 (IC50 5 μM) induced 200 μg/mL of NO and JM14 induced NO production in three different concentrations tested. The compound LIZ331 induced the production of TNF and IL-6. LIZ311 induced the secretion of TNF, IFNγ, IL-2, IL-4, IL-10, and IL-17, cell death by apoptosis, decreased acidic compartment formation, and induced changes in the mitochondrial membrane potential. Taken together, LIZ311 is a promising anti-T. cruzi compound is not toxic to mammalian cells and has increased antiparasitic activity and immunomodulatory properties.

Abstract 1410: An effect of Phenylalanine hydroxylase (PAH) deficiency on cancer development in kidney

Abstract Several studies have noted the importance of amino acid metabolism in cancer progression. Preliminary research using public cancer multi-omics data has revealed associations between heterozygous germline mutations in genes associated with amino acid metabolism and cancer development. In particular, the heterozygous status of the PAH gene enhances the risk of developing kidney cancer by more than three times. Phenylalanine hydroxylase (PAH) is an enzyme that converts phenylalanine to tyrosine. It is highly expressed in the liver and kidneys. Analysis of the blood metabolome in prospectively collected PAH heterozygous carriers indicates that heterozygous status causes metabolome fluctuations in the body. By the way, renal cell carcinoma (RCC) is an immunogenic tumor mainly infiltrated by T cells. Accordingly, we suggest that defects in the PAH gene change the metabolites in the body, leading to a reduction in immune function and an increased risk of developing kidney cancer. First, the expression of the PAH protein was confirmed through immunohistochemistry in a tissue microarray from RCC patients, and the results were then compared with clinical information. Next, we simulated the environment of PAH deficiency in vitro by treating the cells with phenylalanine (Phe) and its metabolite, phenylpyruvate (PRA), which accumulates during PAH dysfunction. The cytotoxicity of Phe and PPA was investigated using the WST assay. The Jurkat T cell line was cultured long-term in a medium containing Phe or PPA and then stimulated with PHA/PMA. Cytokine secretion was confirmed in these supernatants. In addition, purified primary human pan T cells were stimulated with Anti-CD3/CD28 in the medium containing either Phe or PPA. Proliferation was evaluated using CFSE staining. The IHC was performed on 467 tissues from RCC patients aged 29 to 101 years. We classified the cases into three scale scores based on the percentage of PAH intensity. Approximately 73% of cases were PAH-negative, and only 27% were positive (score 1+ or 2+). A comparison of IHC results with clinical information showed that lower PAH expression was associated with a lower relapse-free survival rate. Next, Phe and PPA exhibited minimal cytotoxicity. The secretion of representative proinflammatory cytokines IL-2 and TNF- α were dose-dependent and significantly decreased with Phe and PPA treatment. Additionally, cell proliferation, a critical step in acquiring effector functions of T cells, was inhibited by treatment with Phe and PPA, particularly in the CD8+ T cell population compared to CD4+ T cells. These results suggest that metabolite changes within the tissue microenvironment of the kidney, caused by Pah defects, may suppress anti-tumor immunity by impairing the function of immune cells. This novel discovery may contribute to the importance of the PAH gene as a new biomarker for diagnosing kidney cancer and to the development of kidney cancer therapy. Citation Format: Seojeong Kim, Jihyun Park, Jeongmin Park, Chaelin Kang, Kyung Chul Moon, Seung Seok Han, Youngil Koh, Sung-Soo Yoon. An effect of Phenylalanine hydroxylase (PAH) deficiency on cancer development in kidney [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 1410.

Abstract 633: Integrin αVβ3 activation by thyroid hormones triggers JAK/STAT oncogenic pathways that promote T cell lymphoma dissemination

Abstract T cell lymphomas (TCL) are a heterogeneous group of lymphoproliferative disorders with poor prognosis. Aberrant activation of JAK/STAT pathway is associated with lymphoma dissemination in TCL patients. Although the FDA approved the use of inhibitors to target this pathway (Ruxolitinib), significant toxic effects have been reported and their use is limited. Thus making an excellent opportunity to study biological factors that regulate the activation of these pathways. In this sense, we recently showed that thyroid hormones (THs) acting through integrin αVβ3 induced TCL proliferation, which is reduced in vitro and in vivo in the presence of integrin αVβ3 pharmacological inhibitor. Our aim is to evaluate the impact of THs on JAK/STAT pathway activation and their implications on anti-lymphoma therapy. For the in vitro assays we used human and murine TCL cell lines. We used EL4 cells and c57bl/6 syngeneic mice for in vivo analysis. Proteomic profiles were evaluated by LC-MS-MS analysis. The GSE58445 database was used for in silico analysis. We found that THs induced STAT1, 3 and 5 phosphorylation in TCL cells and that the integrin αVβ3 inhibitor, Cilengitide (Cile) blunted these effects (p<0.05). Interestingly, we found that high mRNA expression levels of integrin β3 significantly correlate with worse overall survival in a cohort of TCL patients (p<0.05). Additionally, Ruxolitinib (Ruxo) diminished THs-induced STATs phosphorylation (p<0.05). As Ruxo reported toxic effects we aim to study alternative therapies such as Bexarotene (Bex), a synthetic retinoid used for cutaneous LCT treatment. We found that Bex significantly reduced cell viability in vitro of all TCL subtypes analyzed and combination with Cile resulted in improved anti-lymphoma activity (p<0.01). Also, Ruxo significantly decreased TCL cell viability but to a lesser extent than Bex+Cile (p<0.05). We previously found that BexT4+Cile (T4+, thyroxine supplementation) significantly decreases the in vivo growth of TCL tumors. To understand the mechanisms under this effects we analyzed tumor proteomics profiles and metalloprotease activity after 12 days of treatment. We found that BexT4+Cile regulates proteomic profiles related not only to lymphoma progression (JAK/STAT and PI3K-Akt signaling) but also pathways that impact the tumor microenvironment (TNF and angiogenic factors secretion and Th1/Th2 T cell differentiation). Regarding metalloprotease activity, we found that BexT+Cile inhibited MMP2 and MMP9 activity (p<0.05). Finally, we evaluated the dissemination of TCL in an in vivo model (by vain tail) and found that BexT4+Cile reduced EL4 cell implantation into the liver and kidneys (p<0.05). These results described the mechanisms by which THs induce the activation of JAK/STAT oncogenic pathway and showed how the inhibition of integrin αvβ3 in combination with bexarotene has therapeutic potential for TCL. Citation Format: María M. Debernardi, María V. Revuelta, Helena Sterle, Gonzalo Gonzalez, Ingrid L M Souza, Alejandro Correa, Leandro Cerchietti, Graciela Cremaschi, Florencia Cayrol. Integrin αVβ3 activation by thyroid hormones triggers JAK/STAT oncogenic pathways that promote T cell lymphoma dissemination [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 633.

Trypanocidal and Anti-Inflammatory Effects of Three ent-Kaurane Diterpenoids from Gymnocoronis spilanthoides var. subcordata (Asteraceae).

Chagas disease, caused by the protozoan Trypanosoma cruzi, affects 6-7 million people worldwide. The dichloromethane extract obtained from the aerial parts of Gymnocoronis spilanthoides var subcordata showed trypanocidal activity in vitro. The fractionation of the dewaxed organic extract via column chromatography led to the isolation of three diterpenoids: ent-9α,11α-dihydroxy-15-oxo-kaur-16-en-19-oic acid or adenostemmoic acid B, (16R)-ent-11α-hydroxy-15-oxokauran-19-oic acid and ent-11α-hydroxy-15-oxo-kaur-16-en-19-oic acid. These compounds showed IC50 values of 10.6, 15.9 and 4.8 µM against T. cruzi epimastigotes, respectively. When tested against amastigotes, the diterpenoids afforded IC50 values of 6.1, 19.5 and 60.6 µM, respectively. The cytotoxicity of the compounds was tested on mammalian cells using an MTT assay, resulting in CC50s of 321.8, 23.3 and 14.8 µM, respectively. The effect of adenostemmoic acid B on T. cruzi was examined at the ultrastructural level using transmission microscopy. Treatment with 20 μM for 48 h stimulated the formation of abnormal cytosolic membranous structures in the parasite. This compound also showed an anti-inflammatory effect in murine macrophages stimulated with LPS and other TLR agonists. Treatment of macrophages with adenostemmoic acid B was able to reduce TNF secretion and nitric oxide production, while increasing IL-10 production. The combination of adenostemmoic acid B with benznidazole resulted in greater inhibition of NF-kB and a decrease in nitrite concentration. The administration of adenostemmoic acid B to mice infected with trypomastigotes of T. cruzi at the dose of 1 mg/kg/day for five days produced a significant decrease in parasitemia levels and weight loss. Treatment with the association with benznidazole increased the survival time of the animals. In view of these results, adenostemmoic acid B could be considered a promising candidate for further studies in the search for new treatments for Chagas disease.

Diverse proinflammatory response in pharyngeal epithelial cells upon interaction with Neisseria meningitidis carriage and invasive isolates

BackgroundInvasive meningococcal disease (IMD), including sepsis and meningitis, can develop when Neisseria meningitidis bacteria breach the barrier and gain access to the circulation. While IMD is a rare outcome of bacterial exposure, colonization of the oropharynx is present in approximately 10% of the human population. This asymptomatic carriage can be long or short term, and it is unknown which determining factors regulate bacterial colonization. Despite descriptions of many bacterial virulence factors and recent advances in detailed genetic identification and characterization of bacteria, the factors mediating invasion and disease vs. asymptomatic carriage following bacterial colonization remain unknown. The pharyngeal epithelia play a role in the innate immune defense against pathogens, and the aim of this study was to investigate the proinflammatory response of pharyngeal epithelial cells following meningococcal exposure to describe the potential inflammatory mediation performed during the initial host‒pathogen interaction. Clinically relevant isolates of serogroups B, C, W and Y, derived from patients with meningococcal disease as well as asymptomatic carriers, were included in the study.ResultsThe most potent cellular response with proinflammatory secretion of TNF, IL-6, CXCL8, CCL2, IL-1β and IL-18 was found in response to invasive serogroup B isolates. This potent response pattern was also mirrored by increased bacterial adhesion to cells as well as induced cell death. It was, however, only with serogroup B isolates where the most potent cellular response was toward the IMD isolates. In contrast, the most potent cellular response using serogroup Y isolates was directed toward the carriage isolates rather than the IMD isolates. In addition, by comparing isolates from outbreaks in Sweden (epidemiologically linked and highly genetically similar), we found the most potent proinflammatory response in cells exposed to carriage isolates rather than the IMD isolates.ConclusionAlthough certain expected correlations between host‒pathogen interactions and cellular proinflammatory responses were found using IMD serogroup B isolates, our data indicate that carriage isolates invoke stronger proinflammatory activation of the epithelial lining than IMD isolates.

Defective Mitophagy Impairs Response to Inflammatory Activation of Macrophage-Like Cells.

The role of mitophagy in atherosclerosis has been extensively studied during the last few years. It was shown that mitophagy is involved in the regulation of macrophages, which are important players as immune cells in atherosclerosis development. In this study, we investigated the relationship between mitophagy and response to inflammatory stimulation of macrophage-like cells. Six cybrid cell lines with normal mitophagy, that is, increasing in response to stimulation, and 7 lines with defective mitophagy not responding to stimulation were obtained. The objective of the study was to compare the nature of the inflammatory response in normal and defective mitophagy in order to elucidate the role of mitophagy defects in inflammation. We used cytoplasmic hybrids (cybrids) as cellular models, created using mitochondrial DNA from different atherosclerosis patients. Mitophagy was stimulated by carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and assessed as the degree of colocalization of mitochondria with lysosomes using confocal microscopy. Western blotting methods were used for the determination of proteins involved in the exact mechanism of mitophagy. Experiments with stimulation of mitophagy show a high correlation between these two approaches (microscopy and blotting). The pro-inflammatory response of cybrids was stimulated with bacterial lipopolysaccharide (LPS). The extent of the inflammatory response was assessed by the secretion of cytokines CCL2, IL8, IL6, IL1β, and TNF measured by ELISA. Basal level of secretion of cytokines CCL2, IL8 and TNF was 1.5-2 times higher in cultures of cybrids with defective mitophagy compared to cells with normal mitophagy. This suggests a persistently elevated inflammatory response in cells with defective mitophagy, even in the absence of an inflammatory stimulus. Such cells in the tissue will constantly recruit other immune cells, which is characteristic of macrophages derived from monocytes circulating in the blood of patients with atherosclerosis. We observed significant differences in the degree and type of response to inflammatory activation in cybrids with defective mitophagy. These differences were not so much quantitative as they were dramatically qualitative. Compared with cells with normal mitophagy, in cells with defective mitophagy, the relative (to basal) secretion of IL8, IL6 and IL1b increased after the second LPS activation. This indicates a possible lack of tolerance to inflammatory activation in cells with defective mitophagy, since typically, re-activation reveals a smaller pro-inflammatory cytokine response, allowing the inflammatory process to resolve. In cells with normal mitophagy, exactly this normal (tolerant) inflammatory reaction was observed. Data on the involvement of mitophagy, including defective mitophagy, in disturbances of the inflammatory response in sepsis, viral infections, autoimmune diseases and other pathologies have previously been reported. In this work, we studied the role of defective mitophagy in non-infectious chronic inflammatory diseases using the example of atherosclerosis. We showed a dramatic disruption of the inflammatory response associated with defective mitophagy. Compared with cybrids with normal mitophagy, in cybrids with defective mitophagy, the secretion of all studied cytokines changed significantly both quantitatively and qualitatively. In particular, the secretion of 3 of 5 cytokines demonstrated an intolerant inflammatory response manifested by increased secretion after repeated inflammatory stimulation. Such an intolerant reaction likely indicates a significant disruption of the pro-inflammatory response of macrophages, which can contribute to the chronification of inflammation. Elucidating the mechanisms of chronification of inflammation is extremely important for the search for fundamentally new pharmacological targets and the development of drugs for the prevention and treatment of chronic inflammatory diseases, including atherosclerosis and diseases characteristic of inflammation. Such diseases account for up to 80% of morbidity and mortality.

The Prolonged Activation of the p65 Subunit of the NF-Kappa-B Nuclear Factor Sustains the Persistent Effect of Advanced Glycation End Products on Inflammatory Sensitization in Macrophages.

Advanced glycation end products (AGEs) prime macrophages for lipopolysaccharide (LPS)-induced inflammation. We investigated the persistence of cellular AGE-sensitization to LPS, considering the nuclear content of p50 and p65 nuclear factor kappa B (NFKB) subunits and the expression of inflammatory genes. Macrophages treated with control (C) or AGE-albumin were rested for varying intervals in medium alone before being incubated with LPS. Comparisons were made using one-way ANOVA or Student t-test (n = 6). AGE-albumin primed macrophages for increased responsiveness to LPS, resulting in elevated levels of TNF, IL-6, and IL-1beta (1.5%, 9.4%, and 5.6%, respectively), compared to C-albumin. TNF, IL-6, and IL-1 beta secretion persisted for up to 24 h even after the removal of AGE-albumin (area under the curve greater by 1.6, 16, and 5.2 times, respectively). The expressions of Il6 and RelA were higher 8 h after albumin removal, and Il6 and Abca1 were higher 24 h after albumin removal. The nuclear content of p50 remained similar, but p65 showed a sustained increase (2.9 times) for up to 24 h in AGE-albumin-treated cells. The prolonged activation of the p65 subunit of NFKB contributes to the persistent effect of AGEs on macrophage inflammatory priming, which could be targeted for therapies to prevent complications based on the AGE-RAGE-NFKB axis.

P034 Peripheral immune cell activity and biopsy gene expression in chronic pouchitis patients treated with tofacitinib: early induction results from the STOPit trial

Abstract Background The Study of TOfacitinib for the treatment of chronic PouchITis (STOPit) is an investigator-initiated, open-label induction, double-blind, placebo-controlled, maintenance withdrawal study to determine the effectiveness of tofacitinib at inducing and maintaining remission in patients with chronic pouchitis. In this interim assessment, we evaluated blood samples and biopsy gene expression collected during the open-label induction period to discover biomarkers of initial clinical response. Methods We collected blood (n = 10 pairs, n = 5 non-responders) and biopsies (n = 21 pairs, n = 9 non-responders) at baseline and after 8 weeks of tofacitinib induction therapy (all participants received 10 mg twice daily induction). We classified patients as responders if they achieved a decrease of ≥ 2 in their modified pouchitis disease activity index after 8 weeks. Bulk peripheral blood mononuclear cells (PBMCs) and memory CD4+ T cells (TMEMs) were isolated from whole blood samples. Cytokines induced by stimulation in the presence or absence of tofacitinib were assessed in culture supernatants by bead array (PBMCs stimulated with PMA/Io or LPS, TMEMs stimulated with CD3/CD28 tetramer). Gene expression was measured in biopsies by qPCR in the pouch and pre-pouch ileum at both time points. Results At baseline, non-responders produced more IL-17 from both their PBMCs stimulated with PMA/Io and TMEMs stimulated with tetramer than responders, but responders secreted more IL-12p70, MCP, IL-10 and IL-8. Tofacitinib inhibited stimulation-induced IL-10 and IL-6 secretion in PBMCs in both responders and non-responders but failed to reduce IFNγ and TNF secretion selectively in non-responders only. All cytokine responses investigated in TMEMs, including IFNγ and TNF, were inhibited by tofacitinib in both responders and non-responders, suggesting the PBMC cell type refractory to inhibition with tofacitinib in non-responders is not TMEMs. Baseline biopsy ileal gene expression of IL18, HES1 and CXCL10 was decreased in responders compared to non-responders, while MMP7 was increased. Clinical response to tofacitinib led to a reduction in pouch expression of GLIS3, G0S2 and WNT5a from baseline to week 8 whereas these genes were unchanged or increased in non-responders. Conclusion Baseline functional immune cell responses and biopsy gene expression may discriminate chronic pouchitis patients' response to tofacitinib therapy and point to a mechanism underlying non-responsiveness. Recruitment for this trial is ongoing, allowing us to bolster and expand our findings with increasing sample sizes.

PAR2 activation on human tubular epithelial cells engages converging signaling pathways to induce an inflammatory and fibrotic milieu.

Key features of chronic kidney disease (CKD) include tubulointerstitial inflammation and fibrosis. Protease activated receptor-2 (PAR2), a G-protein coupled receptor (GPCR) expressed by the kidney proximal tubular cells, induces potent proinflammatory responses in these cells. The hypothesis tested here was that PAR2 signalling can contribute to both inflammation and fibrosis in the kidney by transactivating known disease associated pathways. Using a primary cell culture model of human kidney tubular epithelial cells (HTEC), PAR2 activation induced a concentration dependent, PAR2 antagonist sensitive, secretion of TNF, CSF2, MMP-9, PAI-1 and CTGF. Transcription factors activated by the PAR2 agonist 2F, including NFκB, AP1 and Smad2, were critical for production of these cytokines. A TGF-β receptor-1 (TGF-βRI) kinase inhibitor, SB431542, and an EGFR kinase inhibitor, AG1478, ameliorated 2F induced secretion of TNF, CSF2, MMP-9, and PAI-1. Whilst an EGFR blocking antibody, cetuximab, blocked PAR2 induced EGFR and ERK phosphorylation, a TGF-βRII blocking antibody failed to influence PAR2 induced secretion of PAI-1. Notably simultaneous activation of TGF-βRII (TGF-β1) and PAR2 (2F) synergistically enhanced secretion of TNF (2.2-fold), CSF2 (4.4-fold), MMP-9 (15-fold), and PAI-1 (2.5-fold). In summary PAR2 activates critical inflammatory and fibrotic signalling pathways in human kidney tubular epithelial cells. Biased antagonists of PAR2 should be explored as a potential therapy for CKD.

Macrophage activity modulation via synergistic effect of a porous substrate and low-field laser therapy

Purpose The aim of this study was to investigate the effect of substrate - polycaprolactone (PCL) based porous membrane modified with rosmarinic acid (RA), (PCL-RA) and to determine the optimal values of low field laser irradiation (LLLT) as stimulators of biological response of RAW 264.7 macrophages. Methods The porous polymer membrane was obtained by the phase inversion method, the addition of rosmarinic acid was 1%wt. The reference material was pure polymer membrane. RAW 264.7 were deposited on the material and then irradiated with a laser with a wavelength of 808 nm, a power of 100 mW, an irradiation dose of 2 J/cm2/cell well, applied continuously (C), (100/2/C) or pulsed (I), (100/2/I). Results Macrophage irradiation resulted in an increase their adhesion. Modifying the PCL membranes with rosmarinic acid had no effect on cell viability on day 3 of the cell culture. Irradiation of macrophages cultured on PCL-RA material increased their viability. Irradiation of macrophages cultured on PCL-RA material decreased macrophage secretion of NO and protein and the increase in TNF and MCP-1 secretion was only transient on day 3 of culture. Conclusions Macrophage irradiation had a positive effect on macrophage attachment. Modification of PCL membranes with rosmarinic acid influenced the biological activity of macrophages. Culture of macrophages on rosmarinic acid-modified PCL membranes and simultaneous irradiation of LLLT cells resulted in anti-inflammatory effects.

Tumor necrosis factor α promotes clonal dominance of KIT D816V+ cells in mastocytosis: role of survivin and impact on prognosis

AbstractSystemic mastocytosis (SM) is defined by the expansion and accumulation of neoplastic mast cells (MCs) in the bone marrow (BM) and extracutaneous organs. Most patients harbor a somatic KIT D816V mutation, which leads to growth factor–independent KIT activation and accumulation of MC. Tumor necrosis factor α (TNF) is a proapoptotic and inflammatory cytokine that has been implicated in the clonal selection of neoplastic cells. We found that KIT D816V increases the expression and secretion of TNF. TNF expression in neoplastic MCs is reduced by KIT-targeting drugs. Similarly, knockdown of KIT or targeting the downstream signaling cascade of MAPK and NF-κB signaling reduced TNF expression levels. TNF reduces colony formation in human BM cells, whereas KIT D816V+ cells are less susceptible to the cytokine, potentially contributing to clonal selection. In line, knockout of TNF in neoplastic MC prolonged survival and reduced myelosuppression in a murine xenotransplantation model. Mechanistic studies revealed that the relative resistance of KIT D816V+ cells to TNF is mediated by the apoptosis-regulator BIRC5 (survivin). Expression of BIRC5 in neoplastic MC was confirmed by immunohistochemistry of samples from patients with SM. TNF serum levels are significantly elevated in patients with SM and high TNF levels were identified as a biomarker associated with inferior survival. We here characterized TNF as a KIT D816V-dependent cytokine that promotes clonal dominance. We propose TNF and apoptosis-associated proteins as potential therapeutic targets in SM.

Cutting Edge: PDGF-DD Binding to NKp44 Costimulates TLR9 Signaling and Proinflammatory Cytokine Secretion in Human Plasmacytoid Dendritic Cells.

NKp44 is a human receptor originally found on activated NK cells, group 1 and group 3 innate lymphoid cells that binds dimers of platelet-derived growth factor D (PDGF-DD). NKp44 is also expressed on tissue plasmacytoid dendritic cells (PDCs), but NKp44-PDGF-DD interaction on PDCs remains unstudied. Engagement of NKp44 with PDGF-DD invitro enhanced PDC secretion of IFN-α, TNF, and IL-6 in response to the TLR9 ligand CpG-ODN, but not TLR7/8 ligands. In tissues, PDCs were found in close contact with PDGF-DD-expressing cells in the high endothelial venules and epithelium of tonsils, melanomas, and skin lesions infected with Molluscum contagiosum. Recombinant PDGF-DD enhanced the serum IFN-α response to systemic HSV-1 infection in a humanized mouse model. We conclude that NKp44 integrates with TLR9 signaling to enhance PDC cytokine production. These findings may have bearings for immune responses to TLR9-based adjuvants, therapy for tumors expressing PDGF-DD, and infections with DNA viruses that induce PDGF-DD expression to enhance viral spread.

Macrophages derived from LPS-stimulated monocytes from individuals with subclinical atherosclerosis were characterized by increased pro-inflammatory activity

ObjectiveAtherosclerosis is characterized by chronic inflammation in the vascular wall. Currently the violation of immune tolerance of innate immune cells is considered as a possible mechanism of chronification of inflammation. The aim of this study is to assess the inflammatory activity and tolerance of monocytes and macrophages in subclinical atherosclerosis. MethodsA total of 55 individuals free from clinical manifestations of atherosclerosis-associated cardiovascular disease with a presence or absence of atherosclerotic plaques in the carotid arteries were included in this study. CD14+ monocytes were isolated from individuals' blood and stimulated with a single dose of lipopolysaccharide (LPS) on day 1 or with double doses of LPS on day 1 and day 6. The secretion of cytokines TNF, IL-1β, IL-6, IL-8, IL-10 and CCL2 were evaluated using ELISA. ResultsOur findings demonstrate that macrophages derived from LPS-stimulated monocytes in individuals with subclinical atherosclerosis exhibited increased secretion of IL-6, IL-10 and CCL2, which was associated with intima-media thickness, body mass index, but not with individuals’ age. Moreover, macrophages from individuals with atherosclerotic plaques exhibited impaired tolerance towards the second LPS stimulation manifested by elevated secretion of the chemoattractant CCL2. ConclusionIncreased secretion of these cytokines by macrophages may contribute to chronic local inflammation in the vascular wall by recruiting other immune cells.

Activation of Nod2 signaling upon norovirus infection enhances antiviral immunity and susceptibility to colitis

ABSTRACT Over 90% of epidemic non-bacterial gastroenteritis are caused by human noroviruses (NoVs), which persist in a substantial subset of people allowing their spread worldwide. This has led to a significant number of endemic cases and up to 70,000 children deaths in developing countries. NoVs are primarily transmitted through the fecal-oral route. To date, studies have focused on the influence of the gut microbiota on enteric viral clearance by mucosal immunity. In this study, the use of mouse norovirus S99 (MNoV_S99) and CR6 (MNoV_CR6), two persistent strains, allowed us to provide evidence that the norovirus-induced exacerbation of colitis severity relied on bacterial sensing by nucleotide-binding oligomerization domain 2 (Nod2). Consequently, Nod2-deficient mice showed reduced levels of gravity of Dextran sodium sulfate (DSS)-induced colitis with both viral strains. And MNoV_CR6 viremia was heightened in Nod2 -/- mice in comparison with animals hypomorphic for Atg16l1, which are prone to aggravated inflammation under DSS. Accordingly, the infection of macrophages derived from WT mice promoted the phosphorylation of Signal Transducer and Activator of Transcription 1 (STAT1) and NOD2’s expression levels. Higher secretion of Tumor Necrosis Factor alpha (TNF α ) following NOD2 activation and better viral clearance were measured in these cells. By contrast, reduced levels of pSTAT1 and blunted downstream secretion of TNF α were found in Nod2-deficient macrophages infected by MNoV_S99. Hence, our results uncover a previously unidentified virus-host-bacterial interplay that may represent a novel therapeutic target for treating noroviral origin gastroenteritis that may be linked with susceptibility to several common illnesses such as Crohn’s disease.