Project description:We have generated resolving neutrophils with anti-inflammatory potency, through applying the pharmacological agent 4-PBA or genetically depleting TRAM molecule. WT murine neutrophils treated with PBS or 4-PBA for overnight were harvested for scRNAseq analysis to examine the generated resolving neutrophil phenotype. In addtion, we have cultured WT and TRAM KO neutrophils and compared the resolving phenotype via scRNAseq analysis.
Project description:To investigate the role of DREAM (a transcriptional repressor) in regulating gene transcription in neutrophils under inflammatory conditions, we conducted the next generation sequencing using unstimulated and TNF-alpha-stimulated neutrophils isolated from WT and DREAM KO mice.
Project description:Inflammation is a physiopathological process triggered by infection or tissue damage. Immune system initiates coordinated sequential steps in response to these danger signals. Once the threat has been contained inflammation has to be subsequently shut down. Inflammation resolution is initiated by the reprogramming of pro-inflammatory macrophages toward a pro-resolving profile. This reprogramming is induced in particular by the non-phlogistic engulfment of apoptotic cells, mostly apoptotic neutrophils, a process called efferocytosis. As a matter of fact, macrophages are an essential linchpin regulating both inflammation triggering and sustaining and inflammation resolution. This duality can be achieved through the tremendous plasticity of these innate immune cells. Indeed, depending on microenvironmental signals (cytokines, efferocytosis, growth factors…) macrophages can adopt numerous diverse and sometimes antagonistic phenotypes. The mechanisms governing these transitions remain relatively scattered especially in human. With this project we propose to explore the mechanisms involved in human macrophage reprogramming toward a pro-resolving profile after efferocytosis. The stakes are high due to the estimated prevalence of chronic inflammatory diseases in Western society is 5 to 7%. Chronic inflammation is a burden to patient due to life-long debilitating illness and increased mortality and is also a burden to society due to high costs for therapy and care. Finding new therapies to limit chronic inflammation establishment and persistence is thus a highly valuable goal.
Project description:By performing transcriptome-wide RNA sequencing (RNA-seq) analysis on the peritoneal neutrophils from Alkbh5-deficient mice (Alkbh5-/-) and Wild-type littermates (Alkbh5+/+) at 12h or 36h after mild cecal ligation and puncture (CLP), respectively, we want to identify potential targets of ALKBH5 and characterize the transcriptional landscape in neutrophils during antibacterial innate defense. Gene Ontology biological processes enrichment analysis of the significantly differentially expressed genes (DEGs) showed that neutrophil migration made up the most significantly enriched biological processes with annotations of neutrophil association upon loss of ALKBH5 in neutrophils, at both 12h and 36h after CLP. Many significantly DEGs also encompassed transcriptional signatures related to neutrophils, specifically to neutrophil influx into the infection site, including chemotaxis, response to chemokine, extravasation, ERK1 and ERK2 cascade, homeostasis of neutrophils. ALKBH5 deletion led to significantly decreased transcript expression of neutrophil migration-promoting Cxcr2 and Nlrp12; while increased transcript expression of neutrophil migration-suppressive Ptger4, Tnc, and Wnk1. These results demonstrated that ALKBH5 imprints migration-promoting transcriptional landscape in neutrophils to enable their migration into the site of infection for antibacterial innate defense.
Project description:We recently discovered that human neutrophils express immunomodulatory glycoproteins carrying unusual and highly truncated paucimannosidic N-glycans (Man1-3GlcNAc2Fuc0-1), but their biosynthesis remains elusive. Guided by the well-characterised truncation pathway in invertebrates and plants in which the N-acetyl-β-D-hexosaminidase (Hex) isoenzymes catalyse paucimannosidic protein (PMP) formation, we here set out to test if the homologous human Hex α and β subunits encoded by HEXA and HEXB drive a similar truncation pathway in human neutrophils. To this end, we performed quantitative glycomics and glycoproteomics of several CRISPR-Cas9-edited Hex-disrupted neutrophil-like HL-60 mutants (HEXA-/- and HEXB-/-) and matching unedited cell lines. Hex disruption was validated using next-generation sequencing, ELISA, proteomics and Hex activity assays. Excitingly, all Hex-disrupted mutants displayed significantly reduced levels of paucimannosylation, particularly of Man2-3GlcNAc2Fuc1, relative to unedited HL-60 suggesting that both HEXA and HEXB contribute to PMP formation via a hitherto unexplored truncation pathway in neutrophils. Quantitative N-glycomics indeed demonstrated reduced utilisation of a putative non-canonical truncation pathway in favour of the canonical elongation pathway in all Hex-disrupted mutants relative to unedited controls. Quantitative glycoproteomics recapitulated the truncation-to-elongation switch in all Hex-deficient mutants and showed a pronounced switch for N-glycoproteins co-trafficking with Hex to the azurophilic granules of neutrophils such as myeloperoxidase. Finally, we supported the Hex-PMP relationship by documenting that primary neutrophils isolated from an early-onset Sandhoff disease patient (HEXB-/-) displayed dramatically reduced paucimannosylation relative to neutrophils from an age-matched unaffected donor. We conclude that both human Hex α and β mediate PMP formation via a putative non-canonical truncation pathway in neutrophils.
Project description:We have generated immune-enhancing neutrophils by culturing murine primary bone marrow derived neutrophils with either super-low dose of LPS. Immune-enhancing neutrophils preferentially express co-stimulatory molecules such as CD74, CD44 and CD86, and exhibit reduced expression of CD11b. Purified bone marrow neutrophils were treated with PBS or 100 pg/ml LPS overnight in the presence of GM-CSF, and harvested for scRNAseq analysis to examine their profiles of gene expression.
Project description:We postulate here that the changes induced by the deletion in neutrophils are similar to the changes that appear in mice lacking p38g/d in the myeloid cell