Protein Kinase C-Delta (PKCδ) Tyrosine Phosphorylation is a Critical Regulator of Neutrophil-Endothelial Cell Interaction in Inflammation.

Abstract

BACKGROUND:

Neutrophil dysfunction plays an important role in inflammation-induced tissue injury. Previously, we identified protein kinase C-δ (PKCδ) as a critical controller of neutrophil activation and trafficking but how PKCδ is regulated in inflammation has not been delineated. PKCδ activity is regulated by tyrosine phosphorylation on multiple sites. Tyrosine155 is a key regulator of apoptosis and gene expression, but its role in proinflammatory signaling is not known.

METHODS:

In-vitro studies - superoxide anion (O2) and neutrophil extracellular traps (NETs) were measured in bone marrow neutrophils (BMN) isolated from wild type (WT) and PKCδY155F knock-in mice (PKCδ tyrosine 155 → phenylalanine). Our novel 3D biomimetic microfluidic assay (bMFA) was used to delineate PKCδ-mediated regulation of individual steps in neutrophil adhesion and migration using WT and PKCδY155F BMN and mouse lung microvascular endothelial cells (MLMVEC). In-vivo studies - WT and PKCδY155F knock-in mice underwent sham or cecal ligation and puncture surgery and the lungs harvested 24 h post-surgery.

RESULTS:

In vitro - PKCδY155F BMN had significantly reduced O2 and NETs release compared with WT. WT BMN, but not PKCδY155F BMN, demonstrated significant adhesion and migration across tumor necrosis factor-activated MLMVEC in bMFA. PKCδ inhibition significantly reduced WT BMN adhesion and migration under low shear and near bifurcations, but had no effect on PKCδY155F BMN. In vivo - mutation of PKCδ tyrosine 155 significantly decreased neutrophil migration into the lungs of septic mice.

CONCLUSIONS:

PKCδ tyrosine 155 is a key phosphorylation site controlling proinflammatory signaling and neutrophil-endothelial cell interactions. These studies provide mechanistic insights into PKCδ regulation during inflammation.

• Authors: Fariborz Soroush, Yuan Tang, Kimberly Guglielmo, Alex Engelmann, Elisabetta Liverani, Akruti Patel, Jordan Langston, Shuang Sun, Satya Kunapuli, Mohammad F Kiani, Laurie E Kilpatrick
• Journal: Shock (Augusta, Ga.) (Shock) Vol. 51 Issue 5 Pg. 538-547 (05 2019) ISSN: 1540-0514 [Electronic] United States
• PMID: 30095599 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Fibronectins
• Superoxides
• Tyrosine
• Phenylalanine
• Peroxidase
• Prkcd protein, mouse
• Protein Kinase C-delta
• Oxygen

Topics

• Animals
• Apoptosis
• Bone Marrow Cells (cytology)
• Cell Adhesion
• Endothelial Cells (cytology)
• Endothelium, Vascular (metabolism)
• Female
• Fibronectins (metabolism)
• Gene Knock-In Techniques
• Inflammation (metabolism)
• Male
• Mice
• Mice, Transgenic
• Microcirculation
• Microfluidics
• Neutrophil Activation
• Neutrophils (cytology)
• Oxygen (metabolism)
• Permeability
• Peroxidase (metabolism)
• Phenylalanine (chemistry)
• Phosphorylation
• Protein Kinase C-delta (genetics, metabolism)
• Sepsis (physiopathology)
• Superoxides (metabolism)
• Tyrosine (chemistry)