Project description:Our objective was to identify the genes in tumor-associated neutrophils that are differentially expressed when uterine tumor-bearing "PRPL" mice are subjected to respiratory hyperoxia versus normoxia housing conditions. Six samples were spread across thw two housing conditions, each with 3 biological replicates. Sequencing provided was 372 million total reads with an average of 81.9% of these reads aligning uniquely to the mouse genome. Reads uniquely mapped to known mRNAs were used to identify gene expression changes between housing conditions using DESeq2. We found that 423 protein-coding genes were differentially expressed (FDR<0.05, excluding genes whose normalized read counts were less than 50 across all six samples) in tumor-associated neutrophils from 4-wk old PRPL mice housed under hyperoxia versus normoxia conditions.
Project description:Neutrophil accumulation in crypt abscesses is a pathological hallmark of ulcerative colitis. Based on recent evidence that mucosal metabolic changes influence disease outcomes, we hypothesized that transmigrating neutrophils influence the transcriptional profile of intestinal epithelia. Microarray studies revealed a cohort of hypoxia-responsive genes regulated by neutrophil-epithelial crosstalk. Real-time O2 sensing indicated that transmigrating neutrophils rapidly deplete microenvironmental O2 sufficient enough to stabilize intestinal epithelial cell hypoxia-inducible factor (HIF). Utilizing HIF reporter mice in a TNBS colitis model, we investigated the relative contribution of neutrophils and the respiratory burst to M-bM-^@M-^\inflammatory hypoxiaM-bM-^@M-^] in vivo. Gp91phox-null mice, which mirror human chronic granulomatous disease, developed accentuated colitis compared to control with exaggerated neutrophil infiltration and diminished inflammatory hypoxia. In conclusion, transcriptional imprinting of host tissue by infiltrating neutrophils modulates the host response to inflammation. Likewise, the respiratory burst contributes fundamentally to localized O2 depletion, resultant microenvironmental hypoxia and effective inflammatory resolution. Two models were employed, direct and indirect. The M-bM-^@M-^\DirectM-bM-^@M-^] migration model entailed establishing a chemotactic gradient (using fMLP) across monolayers of T84 intestinal epithelial cells grown on the underside of permeable supports (3um pore). Neutrophils (PMN) were induced to migrate in the physiologically relevant the physiologically relevant basolateral-to-apical direction. Following migration, T84s were rested in complete media and 2hrs later harvested for RNA isolation. In the Indirect model, PMN were applied to T84s as with the direct model. After migration, conditioned supernatants were collected, cells pelleted and supernatants filtered through 0.2um pore. Conditioned supernatants were transferred to naive T84 monolayers for 2hrs, followed by RNA harvest. Each model was exposed to neutrophils (PMN) or not. All monolayers contained chemotactic peptide fMLP on the apical side. Total of 12 samples, 4 conditions in triplicate: Direct migration without neutrophils (T84 +fMLP -PMN), Direct migration with neutrophils (T84 +fMLP +PMN), Indirect migration without neutrophils (T84 +fMLP -PMN), Indirect migration with neutrophils (T84 +fMLP +PMN)
Project description:Neutrophil accumulation in crypt abscesses is a pathological hallmark of ulcerative colitis. Based on recent evidence that mucosal metabolic changes influence disease outcomes, we hypothesized that transmigrating neutrophils influence the transcriptional profile of intestinal epithelia. Microarray studies revealed a cohort of hypoxia-responsive genes regulated by neutrophil-epithelial crosstalk. Real-time O2 sensing indicated that transmigrating neutrophils rapidly deplete microenvironmental O2 sufficient enough to stabilize intestinal epithelial cell hypoxia-inducible factor (HIF). Utilizing HIF reporter mice in a TNBS colitis model, we investigated the relative contribution of neutrophils and the respiratory burst to “inflammatory hypoxia” in vivo. Gp91phox-null mice, which mirror human chronic granulomatous disease, developed accentuated colitis compared to control with exaggerated neutrophil infiltration and diminished inflammatory hypoxia. In conclusion, transcriptional imprinting of host tissue by infiltrating neutrophils modulates the host response to inflammation. Likewise, the respiratory burst contributes fundamentally to localized O2 depletion, resultant microenvironmental hypoxia and effective inflammatory resolution.
Project description:Neutrophil gene transcription following lipopolysaccharide exposure. Microarray analysis of lipopolysaccharide-treated human neutrophils. Neutrophils respond to infection by degranulation, release of reactive oxygen intermediates, and secretion of chemokines and cytokines; however, activation of neutrophil transcriptional machinery has been little appreciated. Recent findings suggest that gene expression may represent an additional neutrophil function after exposure to lipopolysaccharide (LPS). We performed microarray gene expression analysis of 4,608 mostly nonredundant genes on LPS-stimulated human neutrophils. Analysis of three donors indicated some variability but also a high degree of reproducibility in gene expression. Twenty-eight verifiable, distinct genes were induced by 4 h of LPS treatment, and 13 genes were repressed. Genes other than cytokines and chemokines are regulated; interestingly, genes involved in cell growth regulation and survival, transcriptional regulation, and interferon response are among those induced, whereas genes involved in cytoskeletal regulation are predominantly repressed. In addition, we identified monocyte chemoattractant protein-1 as a novel LPS-regulated chemokine in neutrophils. Included in these lists are five clones with no defined function. These data suggest molecular mechanisms by which neutrophils respond to infection and indicate that the transcriptional potential of neutrophils is greater than previously thought.
Project description:Hypoxia-driven alterations in the B16 melanoma cell transcriptome account for a higher metastatic potential: evidence for a role of Ero1L We analyzed transcriptomic adaptations to hypoxia/reoxygenation in B16 melanoma cells. By Ero1L over- and down-expression in vivo, we identified this ER oxidase as an actor of tumor growth and metastasis take. In vitro culture of B16 submitted to hypoxia (oxygen rate less than 1%)
Project description:The neural stem cell (NSC) niche controls the expansion and differentiation of NSCs. Blood vessels are part of this neurogenic niche, but their functional significance for the regulation of NSC differentiation and the mechanisms involved remain unclear. Here, we report that blood vessel formation in the developing mouse and ferret cortex coincided with induction of NSC differentiation in time and space. Moreover, selective inhibition of brain angiogenesis in vessel-specific Gpr124 null embryos caused hypoxia and increased NSC expansion at the expense of differentiation. The hypoxia-inducible factor (HIF)-1Îą mediated this process, as the level of HIF-1Îą controlled NSC differentiation. Niche blood vessels regulated NSC differentiation at least in part by providing oxygen, as exposure to increased ambient oxygen levels rescued NSC differentiation in hypoxic brains of Gpr124 deficient embryos. Our findings establish a novel oxygen-dependent mechanism of how blood vessels regulate NSC differentiation.
Project description:Hypoxia-driven alterations in the B16 melanoma cell transcriptome account for a higher metastatic potential: evidence for a role of Ero1L We analyzed transcriptomic adaptations to hypoxia/reoxygenation in B16 melanoma cells. By Ero1L over- and down-expression in vivo, we identified this ER oxidase as an actor of tumor growth and metastasis take.