Mechanisms and implications of phosphoinositide 3-kinase δ in promoting neutrophil trafficking into inflamed tissue

Blood ◽  
2004 ◽  
Vol 103 (9) ◽  
pp. 3448-3456 ◽  
Author(s):  
Kamal D. Puri ◽  
Teresa A. Doggett ◽  
Jason Douangpanya ◽  
Yonghao Hou ◽  
William T. Tino ◽  
...  

Abstract The phosphoinositide 3-kinase (PI3K) catalytic subunit p110δ is expressed in neutrophils and is thought to play a role in their accumulation at sites of inflammation by contributing to chemoattractant-directed migration. We report here that p110δ is present in endothelial cells and participates in neutrophil trafficking by modulating the proadhesive state of these cells in response to tumor necrosis factor α (TNFα). Specifically, administration of the selective inhibitor of PI3Kδ, IC87114, to animals reduced neutrophil tethering to and increased rolling velocities on cytokine-activated microvessels in a manner similar to that observed in mice deficient in p110δ. These results were confirmed in vitro as inhibition of this isoform in endothelium, but not neutrophils, diminished cell attachment in flow. A role for PI3Kδ in TNFα-induced signaling is demonstrated by a reduction in Akt-phosphorylation and phosphatidylinositol-dependent kinase 1 (PDK1) enzyme activity upon treatment of this cell type with IC87114. p110δ expressed in neutrophils also contributes to trafficking as demonstrated by the impaired movement of these cells across inflamed venules in animals in which this catalytic subunit was blocked or genetically deleted, results corroborated in transwell migration assays. Thus, PI3Kδ may be a reasonable therapeutic target in specific inflammatory conditions as blockade of its activity reduces neutrophil influx into tissues by diminishing their attachment to and migration across vascular endothelium. (Blood. 2004;103:3448-3456)

1997 ◽  
Vol 273 (6) ◽  
pp. R1885-R1890 ◽  
Author(s):  
Tom Van Der Poll ◽  
Stephen F. Lowry

Epinephrine has been found to inhibit the production of the proinflammatory cytokine tumor necrosis factor (TNF)-α and to enhance the production of anti-inflammatory cytokine interleukin (IL)-10. To determine the effect of epinephrine on IL-1β production, the following experiments were performed: 1) blood obtained from subjects at 4–21 h after the start of a continuous infusion of epinephrine (30 ng ⋅ kg−1⋅ min−1) produced less IL-1β after ex vivo stimulation with lipopolysaccharide (LPS), compared with blood drawn from subjects infused with saline; 2) in whole blood in vitro, epinephrine caused a dose-dependent decrease in LPS-induced IL-1β production, which was likely mediated via adrenergic receptors; and 3) inhibition of TNF and enhancement of IL-10 both contributed to epinephrine-induced inhibition of IL-1β production. Epinephrine, either endogenously produced or administered as a component of sepsis treatment, may attenuate excessive activity of proinflammatory cytokines early in the course of systemic infection.


Endocrinology ◽  
1998 ◽  
Vol 139 (5) ◽  
pp. 2278-2283 ◽  
Author(s):  
Brian N. Finck ◽  
Keith W. Kelley ◽  
Robert Dantzer ◽  
Rodney W. Johnson

Blood ◽  
2009 ◽  
Vol 113 (21) ◽  
pp. 5111-5120 ◽  
Author(s):  
Michael D. Milsom ◽  
Bernhard Schiedlmeier ◽  
Jeff Bailey ◽  
Mi-Ok Kim ◽  
Dandan Li ◽  
...  

AbstractEctopic delivery of HOXB4 elicits the expansion of engrafting hematopoietic stem cells (HSCs). We hypothesized that inhibition of tumor necrosis factor-α (TNF-α) signaling may be central to the self-renewal signature of HOXB4. Because HSCs derived from Fanconi anemia (FA) knockout mice are hypersensitive to TNF-α, we studied Fancc−/− HSCs to determine the physiologic effects of HOXB4 on TNF-α sensitivity and the relationship of these effects to the engraftment defect of FA HSCs. Overexpression of HOXB4 reversed the in vitro hypersensitivity to TNF-α of Fancc−/− HSCs and progenitors (P) and partially rescued the engraftment defect of these cells. Coexpression of HOXB4 and the correcting FA-C protein resulted in full correction compared with wild-type (WT) HSCs. Ectopic expression of HOXB4 resulted in a reduction in both apoptosis and reactive oxygen species in Fancc−/− but not WT HSC/P. HOXB4 overexpression was also associated with a significant reduction in surface expression of TNF-α receptors on Fancc−/− HSC/P. Finally, enhanced engraftment was seen even when HOXB4 was expressed in a time-limited fashion during in vivo reconstitution. Thus, the HOXB4 engraftment signature may be related to its effects on TNF-α signaling, and this pathway may be a molecular target for timed pharmacologic manipulation of HSC during reconstitution.


2021 ◽  
Author(s):  
◽  
Sandi Grainne Dempsey

<p>Biomaterials derived from decellularised extracellular matrices have shown promise as tools in tissue regeneration and wound healing. Such materials display biocompatibility as well as inherent bioactivity, promoting constructive remodelling in healing tissues. In this study, the bioactivity of ovine forestomach matrix (a decellularised extracellular matrix biomaterial) is assessed based on its ability to affect the proliferation and migration of wound healing cells.  This material supported cell attachment and proliferation, but did not allow cell infiltration in vitro. Enzymatic digestion of the material rendered soluble components that were able to induce proliferation and migration of some cell types. Cell-mediated processing of the material generated a protein or proteins with chemotactic activity for mesenchymal stem cells in vitro. Mass spectrometry analysis indicated the bioactive component consisted of the proteoglycan decorin, or fragments thereof. Decorin has not previously been shown to induce mesenchymal stem cell motility, and these findings may add to what is known about decorin and its role in constructive remodelling. Furthermore, this cell-mediated approach for ECM breakdown could lead to the discovery of other bioactive peptides involved in ECM remodelling and wound healing.</p>


2020 ◽  
Author(s):  
Samuel Schmidt ◽  
Bettina Weigelin ◽  
Joost te Riet ◽  
Veronika te Boekhorst ◽  
Mariska te Lindert ◽  
...  

SummaryCell migration is a force-dependent adaptive process mediated by integrin-dependent adhesion as well as other yet poorly defined interactions to the extracellular matrix. Using enzymatic multi-targeted digestion of sugar moieties on the surface of mesenchymal cells and leukocytes after interference with integrin function, we demonstrate that the surface glycocalyx represents an independent adhesion system. The glycocalyx mediates cell attachment to ECM ligand in the 100-500 pN force range and amoeboid migration in 3D environments in vitro and in vivo. Glycan-based adhesions consist of actin-rich membrane deformations and appositions associated with bleb-like and other protrusions forming complex-shaped sub-micron contact sites to ECM fibrils. These data implicate the glycocalyx in mediating generic stickiness to support nanoscale interactions (nanogrips) between the cell surface and ECM, mechano-coupling, and migration.


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