Dataset Information

Remodelling of the endothelial cell transcriptional program via paracrine and DNA-binding activities of MPO [polyA-enriched total RNA-Seq]

ABSTRACT: Myeloperoxidase (MPO) is an enzyme, which functions in host defence by catalysing the formation of reactive oxygen intermediates. Synthesized majorly by myeloid progenitor cell types and neutrophils MPO is released into vascular lumen during inflammation, where it may adhere and internalize the endothelial cells coating vascular walls. Here we describe the moonlighting properties of MPO and its regulation of gene transcription in endothelial cells upon nuclear internalization. We show that MPO independently of its enzymatic activity possess chromatin binding properties in vitro and in cyto. Upon nuclear translocation, MPO changes chromatin condensation. Locally at sites of binding, MPO drives de-condensation of chromatin and at the regions flanking MPO binding sites drives an increased chromatin condensation. MPO-guided changes in chromatin condensation lead to activation of endothelial-to-mesenchymal transition in ECs and enhanced migratory potential. Moreover, MPO directly binds to the double-stranded RNA binding protein and transcription factor ILF3 and facilitates translocation of its isoform NF90 into the nucleus. This results in positive regulation of expression of VEGFA, as well lowered stability of CXCL1 and CXCL8 transcripts due to loss of cytoplasmic ILF3.

ORGANISM(S): Homo sapiens

PROVIDER: GSE202014 | GEO | 2023/05/03

REPOSITORIES: GEO

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Project description:The etiopathogenesis underlying myeloperoxidase anti-neutrophil cytoplasmic antibody associated glomerulonephritis (MPO-AAGN) remains incompletely understood. Furthermore, there are only limited treatment options and treatment resistance of MPO-AAGN is still a common problem. To identify new targeted treatment options, intrarenal single-cell RNA sequencing (scRNA-seq) was applied to kidney biopsies from MPO-AAGN patients and control health kidney tissues to define the transcriptomic landscape at single-cell resolution. Intrarenal scRNAseq was also applied to a pre-clinical mouse model of MPO-AAGN to show that this model of disease can be used to trial new targeted treatments. NF-κB pathway activation was confirmed in a variety of kidney cells in MPO-AAGN patients. Kidney infiltrating immune cells of MPO-AAGN patients were mainly enriched in inflammatory pathways including TNF signaling, IL-17 signaling and NOD-like receptor signaling. These findings were similar in our pre-clinical mouse model of MPO-AAGN. Furthermore, there was an overexpression of inflammasome related genes (AIM2, IFI16) in MPO-AAGN patients. A dynamic gene expression in glomerular resident cells was observed in MPO-AAGN, including increased expression of several genes, including CD9 and SPARC, which were closely related to parietal epithelial hyperplasia and crescent formation and lesion progression. Importantly, overexpression of HSP90AA1 in non-focal mesangial cells and endothelial cells was found and the expression of several chemokines (CCL20, CXCL3, CXCL8, CXCL1, CCL2) were upregulated in non-focal proximal tubule cells. Moreover, MPO-AAGN patients with treatment resistance had higher proportions of kidney infiltrating classical monocytes and CD8+ T cells. Elevated expression of SPARC and LAMA4 in mesangial cells, IL33 in endothelial cells, and CFL1 in several cell clusters (proximal tubule cells, loop of Helen, macrophages) were observed in MPO-AAGN patients with treatment resistance when compared with patients who achieved remission after induction therapy. These results offer new insight into the pathogenesis of the progression and treatment resistance MPO-AAGN. We have identified new therapeutic targets for MPO-AAGN that can be tested in a pre-clinical model of disease.

Project description:Human Umbilical Vein Endothelial Cells pooled from several donors, were purchased from Lonza and cultured in FBS reduced Endopan 3 media. HUVEC cells of passages 5-10 were used for experiments. MPO treatment was performed with protein purified from human blood (Planta) and at 1 μg/ml final concentration. Immunoprecipitation was performed from isolated nuclei (after 8 hours MPO treatment), non-treated cells were used as negative control. For immunoprecipitation antibody against MPO (Calbiochem, 475915) was used. Cell nuclei were isolated by incubating cells for 15 min on ice in NIB buffer (15 mM Tris-HCL pH 7.5, 60 mM KCl, 15 mM NaCl, 5 mM MgCl2, 1 mM CaCl2, 250 mM sucrose) containing 0.3% NP-40. Nuclei were pelleted for 5 min 800 × g at 4 °C, washed twice in the same buffer, lysed for 10 min on ice in IP buffer (150 mM LiCl, 50 mM Tris-HCl pH 7.5, 1 mM EDTA, 0.5% Empigen) freshly supplemented with 2 mM sodium vanadate, 1× protease inhibitor cocktail (Roche), PMSF (10 µl), 0,5 mM DTT, and 50 units Benzonase per ml of IP buffer, before preclearing cell debris by centrifugation at >15,000 × g at 4 °C. Finally, 1 mg of the lysate was incubated with anti-MPO antisera overnight at 4 °C. Magnetic beads (Active Motif) were then washed once with 1× PBS-Tween and combined with the antibody-lysate mixture. Following a 2-h incubation at 4 °C, beads were separated on a magnetic rack and washed 5×, 5 min each in wash buffer (150 mM KCl, 5 mM MgCl2, 50 mM Tris-HCl pH 7.5, 0.5% NP-40) and another two times in wash buffer without NP-40. Captured proteins were predigested and eluted from the beads using digestion buffer (2 M Urea, 50 mM Tris-HCl pH 7.5, 1 mM DTT) supplemented with trypsin and eluted from the beads with elution buffer (2 M Urea, 50 mM Tris-HCl pH 7.5, 5 mM chloroacetamide) supplemented with trypsin and LysC, before subjected to mass-spectrometry on a Q-Exactive Plus Orbitrap platform coupled to an EASY nLC (Thermo Scientific). Peptides were loaded in solvent A (0.1% formic acid in water) onto an in-house packed analytical column (50 cm length, 75 µm I.D., filled with 2.7 µm Poroshell EC120 C1; Agilent)