Dataset Information

NF-?B Links TLR2 and PAR1 to Soluble Immunomodulator Factor Secretion in Human Platelets.

ABSTRACT: The primary toll-like receptor (TLR)-mediated immune cell response pathway common for all TLRs is MyD88-dependent activation of NF-?B, a seminal transcription factor for many chemokines and cytokines. Remarkably, anucleate platelets express the NF-?B machinery, whose role in platelets remains poorly understood. Here, we investigated the contribution of NF-?B in the release of cytokines and serotonin by human platelets, following selective stimulation of TLR2 and protease activated receptor 1 (PAR1), a classical and non-classical pattern-recognition receptor, respectively, able to participate to the innate immune system. We discovered that platelet PAR1 activation drives the process of NF-?B phosphorylation, in contrast to TLR2 activation, which induces a slower phosphorylation process. Conversely, platelet PAR1 and TLR2 activation induces similar ERK1/2, p38, and AKT phosphorylation. Moreover, we found that engagement of platelet TLR2 with its ligand, Pam3CSK4, significantly increases the release of sCD62P, RANTES, and sCD40L; this effect was attenuated by incubating platelets with a blocking anti-TLR2 antibody. This effect appeared selective since no modulation of serotonin secretion was observed following platelet TLR2 activation. Platelet release of sCD62P, RANTES, and sCD40L following TLR2 or PAR1 triggering was abolished in the presence of the NF-?B inhibitor Bay11-7082, while serotonin release following PAR1 activation was significantly decreased. These new findings support the concept that NF-?B is an important player in platelet immunoregulations and functions.

SUBMITTER: Damien P

PROVIDER: S-EPMC5292648 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

NF-κB Links TLR2 and PAR1 to Soluble Immunomodulator Factor Secretion in Human Platelets.

Damien Pauline P Cognasse Fabrice F Payrastre Bernard B Spinelli Sherry L SL Blumberg Neil N Arthaud Charles-Antoine CA Eyraud Marie-Ange MA Phipps Richard P RP McNicol Archibald A Pozzetto Bruno B Garraud Olivier O Hamzeh-Cognasse Hind H

Frontiers in immunology 20170206

The primary toll-like receptor (TLR)-mediated immune cell response pathway common for all TLRs is MyD88-dependent activation of NF-κB, a seminal transcription factor for many chemokines and cytokines. Remarkably, anucleate platelets express the NF-κB machinery, whose role in platelets remains poorly understood. Here, we investigated the contribution of NF-κB in the release of cytokines and serotonin by human platelets, following selective stimulation of TLR2 and protease activated receptor 1 (PA ...[more]

PMID: 28220122

Similar Datasets

Project description:Anti-platelet drugs are the mainstay of pharmacotherapy for heart attack and stroke prevention, yet improvements are continually sought. Thrombin is the most potent activator of platelets and targeting platelet thrombin receptors (protease-activated receptors; PARs) is an emerging anti-thrombotic approach. Humans express two PARs on their platelets-PAR1 and PAR4. The first PAR1 antagonist was recently approved for clinical use and PAR4 antagonists are in early clinical development. However, pre-clinical studies examining platelet PAR function are challenging because the platelets of non-primates do not accurately reflect the PAR expression profile of human platelets. Mice, for example, express Par3 and Par4. To address this limitation, we aimed to develop a genetically modified mouse that would express the same repertoire of platelet PARs as humans. Here, human PAR1 preceded by a lox-stop-lox was knocked into the mouse Par3 locus, and then expressed in a platelet-specific manner (hPAR1-KI mice). Despite correct targeting and the predicted loss of Par3 expression and function in platelets from hPAR1-KI mice, no PAR1 expression or function was detected. Specifically, PAR1 was not detected on the platelet surface nor internally by flow cytometry nor in whole cell lysates by Western blot, while a PAR1-activating peptide failed to induce platelet activation assessed by either aggregation or surface P-selectin expression. Platelets from hPAR1-KI mice did display significantly diminished responsiveness to thrombin stimulation in both assays, consistent with a Par3-/- phenotype. In contrast to the observations in hPAR1-KI mouse platelets, the PAR1 construct used here was successfully expressed in HEK293T cells. Together, these data suggest ectopic PAR1 expression is not tolerated in mouse platelets and indicate a different approach is required to develop a small animal model for the purpose of any future preclinical testing of PAR antagonists as anti-platelet drugs.

Dataset Information

NF-?B Links TLR2 and PAR1 to Soluble Immunomodulator Factor Secretion in Human Platelets.

Publications

NF-κB Links TLR2 and PAR1 to Soluble Immunomodulator Factor Secretion in Human Platelets.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets