Project description:CXCL8 is produced by many cell types including epithelial, endothelial, fibroblasts and macrophages in response to TLR recognition of microbe-associated molecular patterns (MAMPs) or inflammatory cytokines and recruits phagocytes from the vasculature to sites of infection via interaction with its cognate receptors CXCR1 and CXCR2. In the intestine, CXCL8 has been demonstrated to participate in the migration of neutrophils across the epithelium during acute inflammation. Given the well-recognized role of CXCL8 as an initiator of inflammation and the constant presence of commensal bacteria in the intestinal tract, we hypothesized that in the intestinal epithelium, CXCL8 might be secreted in a vectorial fashion depending on the location and type of stimulus as a mechanism to maintain homeostasis. In addition, we hypothesized that the CXCR1 receptor might control specific functions in polarized IECs depending on its location. We tested these hypotheses using microarray gene expression profiling of IL-8 treated and mock-treated Caco-2 cell lines This study was set up according to a one-treatment, one-control design. It contains individual transcriptional profiles from 3 IL-8-treated and 3 buffer control-treated samples. In total, this study includes data from 3 Caco-2 samples x 2 treatments=6 arrays.
Project description:CXCL8 is produced by many cell types including epithelial, endothelial, fibroblasts and macrophages in response to TLR recognition of microbe-associated molecular patterns (MAMPs) or inflammatory cytokines and recruits phagocytes from the vasculature to sites of infection via interaction with its cognate receptors CXCR1 and CXCR2. In the intestine, CXCL8 has been demonstrated to participate in the migration of neutrophils across the epithelium during acute inflammation. Given the well-recognized role of CXCL8 as an initiator of inflammation and the constant presence of commensal bacteria in the intestinal tract, we hypothesized that in the intestinal epithelium, CXCL8 might be secreted in a vectorial fashion depending on the location and type of stimulus as a mechanism to maintain homeostasis. In addition, we hypothesized that the CXCR1 receptor might control specific functions in polarized IECs depending on its location. We tested these hypotheses using microarray gene expression profiling of IL-8 treated and mock-treated Caco-2 cell lines
Project description:The heterogeneity of tumor cells enables cancers to dynamically adapt to microenvironmental stresses during progression. However, the mechanism underlying the transformation and intercellular communication between heterogeneous tumor cells has remained elusive. Here, we report a “contagion model” that mediates intercellular transformation between heterogeneous tumor cells which facilitates tumor progression. Initially identifying heterogeneous expression of CXCR1, a receptor for interleukin-8, in head and neck squamous cell carcinoma (HNSCC) tumor cells, we found that CXCR1-High cells transformed CXCR1-Low cells into CXCR1-High cells through the secretion of small extracellular vesicles.We demonstrate that sEVs derived from interleukin-8-activated CXCR1-High cells contain high levels of ATP citrate lyase (ACLY) mediated this process.
Project description:Application of allergens onto the sublingual epithelium is used to desensitize allergic individuals, a treatment known as sublingual immunotherapy. However, the response of sublingual epithelial cells to house dust mite allergen and potential tolerance-promoting adjuvants such as Toll-like receptor ligands and calcitriol has not been investigated. In order to study this, primary sublingual epithelial cells were isolated from dogs and cultured in vitro. After 24h incubation with Dermatophagoides farinae extract, TLR2 ligands (FSL-1, heat-killed Listeria monocytogenes, Pam3CSK4), a TLR3 ligand (poly I:C), a TLR4 ligand (LPS) and calcitriol (1,25-dihydroxyvitamin D3), viability of the cells was analyzed using an MTT test and their secretion of IL-6, IL-10, CXCL8 and TGF-β1 was measured by ELISA. Additionally, to evaluate its potential effect as an adjuvant, sublingual epithelial cells were incubated with calcitriol in combination with D. farinae extract followed by measurement of CXCL8 secretion. Furthermore, the effect of D. farinae and calcitriol on the transcriptome was assessed by RNA-sequencing. The viability of the sublingual epithelial cells was significantly decreased by poly I:C, but not by the other stimuli. CXCL8 secretion was significantly increased by D. farinae extract and all TLR ligands apart from LPS. Calcitriol significantly decreased CXCL8 secretion and co-administration with D. farinae extract reduced CXCL8 concentrations to levels seen in unstimulated sublingual epithelial cells. Although detectable, TGF-β1 secretion could not be modulated by any of the stimuli. IL-6 and IL-10 could not be detected at the protein nor at the mRNA level. It can be concluded that D. farinae extract and TLR ligands augment the secretion of the pro-inflammatory chemokine CXCL8, which might interfere with sublingual desensitization. On the other hand, CXCL8 secretion was reduced by co-application of calcitriol and D. farinae extract. Calcitriol therefore seems to be a suitable candidate to be used as adjuvant during sublingual immunotherapy.
Project description:Respiratory viruses pose an ongoing threat to human health, with excessive cytokine secretion playing a critical role in severe illness and mortality. However, the complex relationship between cytokine secretion and viral infection remains poorly understood. Here, we have unraveled the role of cxcl8 as an early response gene to respiratory EV-D68 infection. The upregulation of CXCL8 by viral infection is found to be crucial for EV-D68 replication. Importantly, silencing CXCL8 or its receptors, CXCR1/2, significantly impedes EV-D68 replication. Upon recognition of CXCL8 by CXCR1/2, the MAPK pathway is activated, facilitating the translocation of the essential host cofactor hnRNP K from the nucleus to the cytoplasm. This translocation enhances the recognition of viral RNA by hnRNP K in the cytoplasm, promoting the functionality of the 5’UTR region in the viral genome. Interestingly, the VP4 structural protein of EV-D68 contains a mimic motif of human immunoreceptor tyrosine-based activation motif (ITAM) that interacts with syk and triggers the PI3K/AKT signaling pathway, resulting in elevated CXCL8 gene expression for viral replication. Moreover, our investigations reveal the conservation and significance of the CXCL8 signaling pathway across various prominent human respiratory viruses, including SARS-CoV-2, influenza, and rhinovirus. In summary, our findings unveil a paradigmatic mechanism through which respiratory viruses exploit cytokine-mediated intercellular communication to transmit signals that optimize viral replication. This deepens our understanding of the shared evolutionary strategies employed by respiratory viruses and opens up new avenues for the development of broad-spectrum antiviral drugs targeting respiratory pathogens.
Project description:The microenvironment is an important regulator of hematopoietic stem and progenitor cell (HSPC) biology. Interactions between the niche and stem cells have been difficult to track, but recent advances marking fluorescent HSPCs have allowed exquisite visualization in the caudal hematopoietic tissue (CHT) of the developing zebrafish. Sinusoidal endothelial cells interact closely with HSPCs as they colonize this niche. Here we show that the chemokine cxcl8 and its receptor, cxcr1, are abundantly expressed by zebrafish endothelial cells and we identify cxcl8/cxcr1 signaling as a positive regulator of HSPC colonization using genetic gain- and loss-of-function techniques. Single-cell tracking experiments demonstrated that this effect is due to an increase in HSPC “cuddling” by endothelial cells, thereby increasing CHT residency time and allowing more HSPC cell divisions to occur. Enhanced cxcl8/cxcr1 signaling was associated with an increase in the volume of the CHT and induction of cxcl12a expression, favoring HSPC colonization. Finally, using parabiotic zebrafish, we show that cxcr1 acts stem cell non-autonomously to improve the efficiency of donor HSPC engraftment. This work identifies a mechanism by which the hematopoietic niche remodels to promote HSPC engraftment and suggests that cxcl8/cxcr1 signaling is a potential therapeutic target in patients undergoing hematopoietic stem cell transplantation.
Project description:The microenvironment is an important regulator of hematopoietic stem and progenitor cell (HSPC) biology. Interactions between the niche and stem cells have been difficult to track, but recent advances marking fluorescent HSPCs have allowed exquisite visualization in the caudal hematopoietic tissue (CHT) of the developing zebrafish. Sinusoidal endothelial cells interact closely with HSPCs as they colonize this niche. Here we show that the chemokine cxcl8 and its receptor, cxcr1, are abundantly expressed by zebrafish endothelial cells and we identify cxcl8/cxcr1 signaling as a positive regulator of HSPC colonization using genetic gain- and loss-of-function techniques. Single-cell tracking experiments demonstrated that this effect is due to an increase in HSPC “cuddling” by endothelial cells, thereby increasing CHT residency time and allowing more HSPC cell divisions to occur. Enhanced cxcl8/cxcr1 signaling was associated with an increase in the volume of the CHT and induction of cxcl12a expression, favoring HSPC colonization. Finally, using parabiotic zebrafish, we show that cxcr1 acts stem cell non-autonomously to improve the efficiency of donor HSPC engraftment. This work identifies a mechanism by which the hematopoietic niche remodels to promote HSPC engraftment and suggests that cxcl8/cxcr1 signaling is a potential therapeutic target in patients undergoing hematopoietic stem cell transplantation.
Project description:Effector CD8+ T cells are believed to be terminally differentiated cells having cytotoxic activity and the ability to produce effector cytokines such as INF-M-NM-3 and TNF-M-NM-1. We investigated the difference between CXCR1+ and CXCR1- subsets of human effector CD27-CD28-CD8+ T cells. Both subsets similarly expressed cytolytic molecules and exerted substantial cytolytic activity, whereas only the CXCR1- subset had IL-2 productivity and self-proliferative activity and was more resistant to cell death than the CXCR1+ subset. These differences were explained by the specific up-regulation of CAMK4, SPRY2, and IL-7R in the CXCR1- subset and that of pro-apoptotic DAPK1 in the CXCR1+ subset. The IL-2 producers were more frequently found in the IL-7R+ subset of the CXCR1- effector CD8+ T cells than in the IL-7R- subset. IL-7/IL-7R signaling promoted cell survival only in the CXCR1- subset. The present study has highlighted a novel subset of effector CD8+ T cells producing IL-2 and suggests the importance of this subset in the homeostasis of effector CD8+ T cells. To find the genes that potentially cause the difference in IL-2 productivity and cell survival between the CXCR1+ and CXCR1- human effector CD8+ T cell subsets, we performed microarray gene expression analysis. We highly purified each CD3+CD8+ subset for this analysis (> 95.3%) from 5 healthy individuals, and then compared the gene expression profiles of each subset.
Project description:The heterogeneity of tumor cells enables cancers to dynamically adapt to microenvironmental stresses during progression. However, the mechanism underlying the transformation and intercellular communication between heterogeneous tumor cells has remained elusive. Here, we report a “contagion model” that mediates intercellular transformation between heterogeneous tumor cells which facilitates tumor progression. Initially identifying heterogeneous expression of CXCR1, a receptor for interleukin-8, in head and neck squamous cell carcinoma (HNSCC) tumor cells. Following interleukin-8-mediated activation, CXCR1High cells transformed CXCR1Low cells into CXCR1High cells through the secretion of small extracellular vesicles (sEVs), which increased the proportion of CXCR1High cells and facilitated tumor progression. Mechanistically, we demonstrate that sEVs derived from interleukin-8-activated CXCR1High cells contain high levels of ATP citrate lyase (ACLY), which acetylates NF-κB p65 and facilitates its nuclear translocation to transcribe CXCR1 in CXCR1Low cells. That process could be inhibited by Bempedoic acid, an FDA-approved ACLY-targeted drug. Taken together, our study reveals an sEV-mediated transformation of CXCR1Low to CXCR1High cells that promotes HNSCC progression. This provides a new paradigm to explain the dynamic changes of heterogeneous tumor cells, and identifies Bempedoic acid as a potential drug for HNSCC treatment.
Project description:Effector CD8+ T cells are believed to be terminally differentiated cells having cytotoxic activity and the ability to produce effector cytokines such as INF-γ and TNF-α. We investigated the difference between CXCR1+ and CXCR1- subsets of human effector CD27-CD28-CD8+ T cells. Both subsets similarly expressed cytolytic molecules and exerted substantial cytolytic activity, whereas only the CXCR1- subset had IL-2 productivity and self-proliferative activity and was more resistant to cell death than the CXCR1+ subset. These differences were explained by the specific up-regulation of CAMK4, SPRY2, and IL-7R in the CXCR1- subset and that of pro-apoptotic DAPK1 in the CXCR1+ subset. The IL-2 producers were more frequently found in the IL-7R+ subset of the CXCR1- effector CD8+ T cells than in the IL-7R- subset. IL-7/IL-7R signaling promoted cell survival only in the CXCR1- subset. The present study has highlighted a novel subset of effector CD8+ T cells producing IL-2 and suggests the importance of this subset in the homeostasis of effector CD8+ T cells.