Upon microbial challenge, human neutrophils undergo rapid changes in nuclear architecture and chromatin folding to orchestrate an immediate inflammatory gene program

Differentiating neutrophils undergo large-scale changes in nuclear morphology. How such alterations in structure are established and modulated upon exposure to microbial agents is largely unknown. Here, we found that prior to encounter with bacteria, an armamentarium of inflammatory genes was positioned in a transcriptionally passive environment suppressing premature transcriptional activation. Upon microbial exposure, however, human neutrophils rapidly (<3 hours) repositioned the ensemble of pro-inflammatory genes towards the transcriptionally permissive compartment. We show that the repositioning of genes was closely associated with the swift recruitment of cohesin across the inflammatory enhancer landscape permitting an immediate transcriptional response upon bacterial exposure. These data reveal at the mechanistic level how upon microbial challenge human neutrophils undergo rapid changes in nuclear architecture to orchestrate an immediate inflammatory gene program.

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Chromatin folding and nuclear architecture: PRC1 function in 3D

Current Opinion in Genetics & Development ◽

10.1016/j.gde.2019.06.006 ◽

2019 ◽

Vol 55 ◽

pp. 82-90 ◽

Cited By ~ 9

Author(s):

Robert S Illingworth

Keyword(s):

Nuclear Architecture ◽

Chromatin Folding

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Rapid changes in histone deacetylases and inflammatory gene expression in expert meditators

Psychoneuroendocrinology ◽

10.1016/j.psyneuen.2013.11.004 ◽

2014 ◽

Vol 40 ◽

pp. 96-107 ◽

Cited By ~ 115

Author(s):

Perla Kaliman ◽

María Jesús Álvarez-López ◽

Marta Cosín-Tomás ◽

Melissa A. Rosenkranz ◽

Antoine Lutz ◽

...

Keyword(s):

Gene Expression ◽

Histone Deacetylases ◽

Inflammatory Gene Expression ◽

Inflammatory Gene ◽

Rapid Changes

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Phospholipid metabolism in human neutrophils activated by N-formyl-methionyl-leucyl-phenylalanine. Degranulation is not required for release of arachidonic acid: studies with neutrophils and neutrophil-derived cytoplasts

Biochemical Journal ◽

10.1042/bj2360829 ◽

1986 ◽

Vol 236 (3) ◽

pp. 829-837 ◽

Cited By ~ 25

Author(s):

E M Wynkoop ◽

M J Broekman ◽

H M Korchak ◽

A J Marcus ◽

G Weissmann

Keyword(s):

Arachidonic Acid ◽

Phosphatidic Acid ◽

Receptor Occupancy ◽

Phospholipid Metabolism ◽

Human Neutrophils ◽

Phospholipid Synthesis ◽

Rapid Changes ◽

Intracellular Organelles

Neutrophils respond to chemoattractants by aggregating, degranulating, remodelling of phospholipids and releasing arachidonic acid. To determine whether ligand-induced remodelling of phospholipids depends on redistribution of intracellular organelles (degranulation), we compared phospholipid remodelling of human neutrophils with that of neutrophil-derived cytoplasts. Cytoplasts, organelle-depleted vesicles of cytosol surrounded by plasmalemma, cannot degranulate. Without a stimulus, [3H]arachidonate was incorporated preferentially into phosphatidylinositol (PI) and phosphatidylcholine (PC). Exposure of cytoplasts and neutrophils prelabelled with [3H]arachidonate or [14C]glycerol to fMet-Leu-Phe (10(-7) M) induced rapid changes in distribution of label and mass of individual phospholipids: [3H]arachidonate in phosphatidic acid (PA) increased 500% (120 s), [14C]glycerol incorporation and mass of PA approached 200% of unstimulated values, and [3H]arachidonate in PI decreased continuously; these data are compatible with activity of a PI/PA cycle. However, the mass of PI in both preparations and [14C]glycerol label in intact neutrophils increased initially (5 s), suggesting net synthesis and mobilization of more than one pool of PI. Heterogeneity of PC pools was also observed: [3H]arachidonate was lost from PC immediately upon addition of stimulus, whereas mass and [14C]glycerol values increased. Thus, net phospholipid synthesis, redistribution of arachidonate and activation of the PI/PA cycle are immediate responses of the neutrophil to receptor occupancy by chemoattractants. Furthermore, the similarity in response to fMet-Leu-Phe of neutrophils and granule-free cytoplasts indicates that these processes are independent of degranulation.

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The ionic strength dependence of chromatin folding

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081966 ◽

1978 ◽

Vol 36 (2) ◽

pp. 220-221

Author(s):

F. Thoma ◽

TH. Koller

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Ionic Strength ◽

Specimen Preparation ◽

Preparation Technique ◽

Carbon Supports ◽

Ionic Strength Dependence ◽

Chromatin Folding ◽

Strength Dependence ◽

Preparation Techniques

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.

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Neutrophil Myeloperoxidase Destruction by Ultraviolet Irradiation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100102778 ◽

1988 ◽

Vol 46 ◽

pp. 138-139

Author(s):

J. Hanker ◽

B. Giammara ◽

G. Strauss

Keyword(s):

Uv Radiation ◽

Myeloid Leukemia ◽

Stratospheric Ozone ◽

Psoriasis Patient ◽

Whole Body ◽

Human Neutrophils ◽

Cupric Nitrate ◽

The Earth ◽

Routine Handling ◽

Uvb Phototherapy

Only a fraction of the UV radiation emitted by the sun reaches the earth; most of the UVB (290-320nm) is eliminated by stratospheric ozone. There is increasing concern, however, that man-made chemicals are damaging this ozone layer. Although the effects of UV on DNA or as a carcinogen are widely known, preleukemia and acute myeloid leukemia (AML) have only rarely been reported in psoriasis patients treated with 8-methoxypsoralen and UV (PUVA). It was therefore of interest to study the effects of UV on the myeloperoxidase (MP) activity of human neutrophils. The peroxidase activity of enriched leukocyte preparations on coverslips was shown cytochemically with a diaminobenzidine medium and cupric nitrate intensification.Control samples (Figs. 1,4,5) of human bloods that were not specifically exposed to UV radiation or light except during routine handling were compared with samples which had been exposed in one of several different ways. One preparation (Fig. 2) was from a psoriasis patient who had received whole-body UVB phototherapy repeatedly.

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Application of high-resolution field-emission LVSEM, backscatter imaging, immunogold staining to definition of the spatial distributions of two human neutrophil adherence receptors

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146023 ◽

1993 ◽

Vol 51 ◽

pp. 36-37

Author(s):

Robert D. Nelson ◽

Sharon R. Hasslen ◽

Stanley L. Erlandsen

Keyword(s):

Cell Surface ◽

Surface Membrane ◽

Three Dimensional ◽

Human Neutrophils ◽

Spatial Distributions ◽

Immunogold Staining ◽

Functional Control ◽

Neutrophil Adherence ◽

Definition Of ◽

Mode Of Attachment

Receptors are commonly defined in terms of number per cell, affinity for ligand, chemical structure, mode of attachment to the cell surface, and mechanism of signal transduction. We propose to show that knowledge of spatial distribution of receptors on the cell surface can provide additional clues to their function and components of functional control.L-selectin and Mac-1 denote two receptor populations on the neutrophil surface that mediate neutrophil-endothelial cell adherence interactions and provide for targeting of neutrophil recruitment to sites of inflammation. We have studied the spatial distributions of these receptors using LVSEM and backscatter imaging of isolated human neutrophils stained with mouse anti-receptor (primary) antibody and goat anti-mouse (secondary) antibody conjugated to 12 nm colloidal gold. This combination of techniques provides for three-dimensional analysis of the expression of these receptors on different surface membrane domains of the neutrophil: the ruffles and microvilli that project from the cell surface, and the cell body between these projecting structures.

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