Alarmin S100A11 initiates a chemokine response to the human pathogen Toxoplasma gondii.
ABSTRACT: Toxoplasma gondii is a common protozoan parasite that infects up to one third of the world's population. Notably, very little is known about innate immune sensing mechanisms for this obligate intracellular parasite by human cells. Here, by applying an unbiased biochemical screening approach, we show that human monocytes recognized the presence of T. gondii infection by detecting the alarmin S100A11 protein, which is released from parasite-infected cells via caspase-1-dependent mechanisms. S100A11 induced a potent chemokine response to T. gondii by engaging its receptor RAGE, and regulated monocyte recruitment in vivo by inducing expression of the chemokine CCL2. Our experiments reveal a sensing system for T. gondii by human cells that is based on the detection of infection-mediated release of S100A11 and RAGE-dependent induction of CCL2, a crucial chemokine required for host resistance to the parasite.
Project description:The Ca2+-sensing protein S100A11 of the S100 family is an important mediator of numerous biological functions and pathological conditions including cancer. The receptor for advanced glycation end products (RAGE) has been well accepted as the major receptor for several S100 family members. Here, we take the S100B protein as an antagonist to interfere with the interaction flanked by S100A11 and the RAGE V domain. We employed NMR spectroscopy to describe the interactions between the S100A11 and S100B proteins. 1H-15N heteronuclear single-quantum correlation-NMR titrations showed the potential binding dynamics of S100A11 and S100B interactions. In the HADDOCK program, we constructed the S100A11-S100B heterodimer complex that was then superimposed with the S100A11-S100B complex structure in the same orientation as the S100A11-RAGE V domain complex. This overlay analysis showed that S100B could interfere in the binding section of S100A11 and the RAGE V domain. Additionally, water-soluble tetrazolium-1 assay provided a functional read-out of the effects of these proteins in an in vitro cancer model. Our study establishes that the development of an S100B antagonist could perform a vital part in the treatment of S100- and RAGE-dependent human diseases.
Project description:Purpose: The goal of this study is to compare NGS-derived transcriptome profiling of human PBMC infected with T. gondii, PRU and RH strains, (RNA-seq) to not stimulated human PBMC transcriptome (RNA-seq). Methods: After 24h post infection PBMC and non-infected PBMC mRNA profiles were generated by deep sequencing. The sequence reads were analyzed within Galaxy platform: FastQC(*) program was used to generate quality control reports followed by employment of Trimmamatic (*) to trim “noisy” ends; TopHat mapped reads to hg38 human genome; Cuffdiff (*) was used to find significant changes in transcript expression between infected with T. gondii human PBMC and not infected PBMC. Results: RNA-seq data for genes with a fold change ≥2.5 and p value <0.05. Conclusions: human innate responses to T. gondii were primarily characterized by the induction of chemokine expression, including CCL2 Overall design: Human PBMC mRNA profiles of infected cell with T. gondii and non infected cells were generated by deep sequencing,in quintuplicate
Project description:The human S100 calcium-binding protein A11 (S100A11) is a member of the S100 protein family. Once S100A11 proteins bind to calcium ions at EF-hand motifs, S100A11 changes its conformation, promoting interaction with target proteins. The receptor for advanced glycation end products (RAGE) consists of three extracellular domains, including the V domain, C1 domain, and C2 domain. In this case, the V domain is the target for mutant S100A11 (mS100A11) binding. RAGE binds to the ligands, resulting in cell proliferation, cell growth, and several signal transduction cascades. We used NMR and fluorescence spectroscopy to demonstrate the interactions between mS100A11and RAGE V domain. The tranilast molecule is a drug used for treating allergic disorders. We discovered that the RAGE V domain and tranilast would interact with mS100A11 by using (1)H-(15)N HSQC NMR titrations. According to the results, we obtained two binary complex models from the HADDOCK program, S100A11-RAGE V domain and S100A11-tranilast, respectively. We overlapped two binary complex models with the same orientation of S100A11 homodimer and demonstrated that tranilast would block the binding site between S100A11 and the RAGE V domain. We further utilized a water-soluble tetrazolium-1 assay to confirm this result. We think that the results will be potentially useful in the development of new anti-cancer drugs.
Project description:In mouse models of biliary tract diseases, macrophages are recruited to the periductal milieu and promote injury and cholestasis. Although cell necrosis with release of biomolecules termed damage-associated molecular patterns (DAMPs) promotes recruitment and activation of macrophages, necrosis was not observed in these studies. Because extracellular vesicles (EVs) are important in cell-to-cell communication, we postulated that activated cholangiocytes may release EVs containing DAMPs as cargo. Both the human (NHC) and mouse cholangiocyte (603B) cell lines display constitutive activation with mRNA expression of chemokines. Proteomic analysis revealed that EVs from both cell lines contained the DAMP S100A11, a ligand for the receptor for advanced glycation end products (RAGE). Bone marrow-derived macrophages (BMDM) incubated with EVs derived from the mouse 603B cell line increased mRNA expression of proinflammatory cytokines. Genetic or pharmacologic inhibition of RAGE reduced BMDM expression of proinflammatory cytokines treated with EVs. RAGE signaling resulted in activation of the canonical NF-?B pathway, and consistently, proinflammatory cytokine expression was blunted by the IKK?/? inhibitor TPCA-1 in BMDM incubated with EVs. We also demonstrated that primary mouse cholangiocyte-derived organoids express chemokines indicating cholangiocyte activation, release EVs containing S100A11, and stimulate proinflammatory cytokine expression in BMDM by a RAGE-dependent pathway. In conclusion, these observations identify a non-cell death mechanism for cellular release of DAMPs by activated cholangiocytes, namely by releasing DAMPs as EV cargo. These data also suggest RAGE inhibitors may be salutary in macrophage-associated inflammatory diseases of the bile ducts.
Project description:Glioblastoma (GBM) is the most universal type of primary brain malignant tumour, and the prognosis of patients with GBM is poor. S100A11 plays an essential role in tumour. However, the role and molecular mechanism of S100A11 in GBM are not clear. Here, we found that S100A11 was up-regulated in GBM tissues and higher S100A11 expression indicated poor prognosis of GBM patients. Overexpression of S100A11 promoted GBM cell growth, epithelial-mesenchymal transition (EMT), migration, invasion and generation of glioma stem cells (GSCs), whereas its knockdown inhibited these activities. More importantly, S100A11 interacted with ANXA2 and regulated NF-κB signalling pathway through decreasing ubiquitination and degradation of ANXA2. Additionally, NF-κB regulated S100A11 at transcriptional level as a positive feedback. We also demonstrated the S100A11 on tumour growth in GBM using an orthotopic tumour xenografting. These data demonstrate that S100A11/ANXA2/NF-κB positive feedback loop in GBM cells that promote the progression of GBM.
Project description:Malignant pleural mesothelioma (MPM) is an aggressive tumor with an unfavorable prognosis. The standard therapeutic approaches are limited to surgery, chemotherapy, and radiotherapy. Because the consequent clinical outcome is often unsatisfactory, a different approach in MPM treatment is required. S100A11, a Ca2+-binding small protein with two EF-hands, is frequently upregulated in various human cancers. Interestingly, it has been found that intracellular and extracellular S100A11 have different functions in cell viability. In this study, we focused on the impact of extracellular S100A11 in MPM and explored the therapeutic potential of an S100A11-targeting strategy. We examined the secretion level of S100A11 in various kinds of cell lines by enzyme-linked immunosorbent assay. Among them, six out of seven MPM cell lines actively secreted S100A11, whereas normal mesothelial cell lines did not secrete it. To investigate the role of secreted S100A11 in MPM, we inhibited its function by neutralizing S100A11 with an anti-S100A11 antibody. Interestingly, the antibody significantly inhibited the proliferation of S100A11-secreting MPM cells in vitro and in vivo. Microarray analysis revealed that several pathways including genes involved in cell proliferation were negatively enriched in the antibody-treated cell lines. In addition, we examined the secretion level of S100A11 in various types of pleural effusions. We found that the secretion of S100A11 was significantly higher in MPM pleural effusions, compared to others, suggesting the possibility for the use of S100A11 as a biomarker. In conclusion, our results indicate that extracellular S100A11 plays important roles in MPM and may be a therapeutic target in S100A11-secreting MPM.
Project description:Alveolar epithelial cells (AECs) are an essential part of the respiratory barrier in lungs for gas exchange and protection against pathogens. Damage to AECs occurs during lung injury and PAMPs/DAMPs have been shown to activate AECs. However, their interplay as well as the mechanism of AECs' activation especially by the alarmin S100A8/A9 is unknown. Thus, our aim was to study the mechanism of activation of AECs (type I and type II) by S100A8 and/or lipopolysaccharide (LPS) and to understand the role of endogenous S100A8/A9 in neutrophil recruitment in the lung. For our studies, we modified a previous protocol for isolation and culturing of murine AECs. Next, we stimulated the cells with S100A8 and/or LPS and analyzed cytokine/chemokine release. We also analyzed the contribution of the known S100-receptors TLR4 and RAGE in AEC activation. In a murine model of lung injury, we investigated the role of S100A8/A9 in neutrophil recruitment to lungs. S100A8 activates type I and type II cells in a dose- and time-dependent manner which could be quantified by the release of IL-6, KC, and MCP-1. We here clearly demonstrate that AEC s are activated by S100A8 via a TLR4-dependent pathway. Surprisingly, RAGE, albeit mainly expressed in lung tissue, plays no role. Additionally, we show that S100A8/A9 is an essential factor for neutrophil recruitment to lungs. We, therefore, conclude that S100A8 promotes acute lung injury via Toll-like receptor 4-dependent activation of AECs.
Project description:We previously revealed a novel signal pathway involving S100A11 for inhibition of the growth of normal human keratinocytes (NHK) caused by high Ca(++) or transforming growth factor beta. Exposure to either agent resulted in transfer of S100A11 to nuclei, where it induced p21(WAF1). In contrast, S100A11 has been shown to be overexpressed in many human cancers. To address this apparent discrepancy, we analyzed possible new functions of S100A11, and we provide herein evidence that 1) S100A11 is actively secreted by NHK; 2) extracellular S100A11 acts on NHK to enhance the production of epidermal growth factor family proteins, resulting in growth stimulation; 3) receptor for advanced glycation end products, nuclear factor-kappaB, Akt, and cAMP response element-binding protein are involved in the S100A11-triggered signal transduction; and 4) production and secretion of S100A11 are markedly enhanced in human squamous cancer cells. These findings indicate that S100A11 plays a dual role in growth regulation of epithelial cells.
Project description:S100 proteins are a group of low molecular weight (10-12 kDa) acidic proteins belonging to the largest family of EFhand calciumbinding proteins. S100A11, also known as S100C or calgizzarin, is an important member of the S100 family. S100A11 overexpression has been reported in a number of cancers including papillary thyroid carcinoma, colon, pancreatic, and breast cancer. One other study demonstrated that increased S100A11 expression is correlated with gastric cancer metastasis and poor overall disease prognosis. This study aimed to identify the function of S100A11 associated with cell proliferation and invasion in gastric cancer. We used cell culture, western blotting, reverse transcription-polymerase chain reaction, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and S100A11 knock-down with short hairpin ribonucleic acid (shRNA). First, we confirmed that the S100A11 expression was upregulated by hepatocyte growth factor (HGF). The role of S100A11 was determined via knock down of S100A11. S100A11-shRNA cells showed decreased levels of metalloproteinase-9 (MMP9) and nuclear factor kappa-B (NF-κB). We also examined and confirmed the role of HGF-mediated S100A11 expression. HGF-mediated cell proliferation and in vitro invasion increased, and HGF-mediated apoptosis decreased in S100A11 knockdown cells. We identified the putative binding site of NF-κB in the MMP9 promoter region and confirmed its function via chromatin immunoprecipitation (CHIP) assay. Our results showed that S100A11 is upregulated by HGF through the NF-κB pathway in gastric cancer and plays a role in cell proliferation and invasion in gastric cancer. It may thus be a possible target for gastric cancer therapy.
Project description:S100A11 is reported to associate with progression and poor prognosis in several tumors. We previously reported that S100A11 was highly expressed in intrahepatic cholangiocarcinoma (ICC) cells and promoted TGF-β1-induced EMT through SMAD2/3 signaling pathway. Here, we explored the prognostic role of S100A11 on ICC patients and preliminary molecular mechanisms how S100A11 regulated ICC cell proliferation. Our results showed that S100A11 was obviously increased in ICC tumor tissues. High expression of S100A11 was closely correlated with lymph node metastasis (LNM) and TNM stage and was an independent risk factor for patients' overall survival (OS) and recurrence-free survival (RFS). The nomograms comprising LNM and S100A11 achieved better predictive accuracy compared with TNM staging system for OS and RFS prediction. Silencing S100A11 significantly suppressed RBE cells and HCCC9810 cells proliferation, colony formation, and activation of P38/mitogen-activated protein kinase (MAPK) signaling pathway in vitro and inhibited tumor growth in vivo. In contrast, the overexpression of S100A11 in RBE cells and HCCC9810 cells achieved the opposite results. S100A11-induced proliferation was abolished after treatment with P38 inhibitor. Our findings suggest S100A11/P38/MAPK signaling pathway may be a potential therapeutic target for ICC patients.