Medical College of Wisconsin
CTSICores SearchResearch InformaticsREDCap

Restoration of responsiveness of phospholipase Cγ2-deficient platelets by enforced expression of phospholipase Cγ1. PLoS One 2015;10(3):e0119739

Date

03/21/2015

Pubmed ID

25793864

Pubmed Central ID

PMC4368822

DOI

10.1371/journal.pone.0119739

Scopus ID

2-s2.0-84925859948   7 Citations

Abstract

Receptor-mediated platelet activation requires phospholipase C (PLC) activity to elevate intracellular calcium and induce actin cytoskeleton reorganization. PLCs are classified into structurally distinct β, γ, δ, ε, ζ, and η isoforms. There are two PLCγ isoforms (PLCγ1, PLCγ2), which are critical for activation by tyrosine kinase-dependent receptors. Platelets express both PLCγ1 and PLCγ2. Although PLCγ2 has been shown to play a dominant role in platelet activation, the extent to which PLCγ1 contributes has not been evaluated. To ascertain the relative contributions of PLCγ1 and PLCγ2 to platelet activation, we generated conditionally PLCγ1-deficient, wild-type (WT), PLCγ2-deficient, and PLCγ1/PLCγ2 double-deficient mice and measured the ability of platelets to respond to different agonists. We found that PLCγ2 deficiency abrogated αIIbβ3-dependent platelet spreading, GPVI-dependent platelet aggregation, and thrombus formation on collagen-coated surfaces under shear conditions, which is dependent on both GPVI and αIIbβ3. Addition of exogenous ADP overcame defective spreading of PLCγ2-deficient platelets on immobilized fibrinogen, suggesting that PLCγ2 is required for granule secretion in response to αIIbβ3 ligation. Consistently, αIIbβ3-mediated release of granule contents was impaired in the absence of PLCγ2. In contrast, PLCγ1-deficient platelets spread and released granule contents normally on fibrinogen, exhibited normal levels of GPVI-dependent aggregation, and formed thrombi normally on collagen-coated surfaces. Interestingly, enforced expression of PLCγ1 fully restored GPVI-dependent aggregation and αIIbβ3-dependent spreading of PLCγ2-deficient platelets. We conclude that platelet activation through GPVI and αIIbβ3 utilizes PLCγ2 because PLCγ1 levels are insufficient to support responsiveness, but that PLCγ1 can restore responsiveness if expressed at levels normally achieved by PLCγ2.

Author List

Zheng Y, Adams T, Zhi H, Yu M, Wen R, Newman PJ, Wang D, Newman DK

Authors

Debra K. Newman PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin
Peter J. Newman PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin
Demin Wang PhD Assistant Professor in the Microbiology and Immunology department at Medical College of Wisconsin
Renren Wen PhD Associate Investigator in the Blood Research Institute department at BloodCenter of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Blood Platelets
Collagen
Enzyme Activation
Gene Expression
Isoenzymes
Mice
Mice, Knockout
Mice, Transgenic
Phospholipase C gamma
Platelet Activation
Platelet Aggregation
Platelet Count
Platelet Glycoprotein GPIIb-IIIa Complex
Thrombosis
jenkins-FCD Prod-469 c3fc8ab87196149f9b23743c01b947d47e7319e5