心肌梗死患者血小板中的 Toll 样受体 4 激活。

Toll-like receptor 4 activation in platelets from myocardial infarction patients.

机构信息

Department of Clinical Internal, Anaesthesiological and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy.

Department of General Surgery and Surgical Speciality Paride Stefanini, Sapienza University of Rome, Rome, Italy.

出版信息

Thromb Res. 2022 Jan;209:33-40. doi: 10.1016/j.thromres.2021.11.019. Epub 2021 Nov 24.

DOI:10.1016/j.thromres.2021.11.019

PMID:34856494

Abstract

INTRODUCTION

Platelet toll-like receptor 4 (TLR4) is overexpressed in patients with myocardial infarction (MI) but it remains to elucidate if it is activated and the potential trigger.

METHODS

Serum levels of lipopolysaccharides (LPS) and platelet aggregation (PA) by collagen alone or in combination with a TLR4 inhibitor (TLR4i) were studied ex vivo in platelets from 40 MI patients and 40 controls matched for age, sex and atherosclerotic risk factors; platelet TIR domain-containing adaptor protein (TIRAP) and TIRAP-MyD88 interaction were also investigated by western blot and co-immunoprecipitation, respectively. In vitro experiments were conducted to see if LPS triggers platelet TIRAP phosphorylation.

RESULTS

Serum LPS was significantly higher in patients compared to controls (29.5±7.1 vs 16.2±3.8 pg/mL; p<0.001). Collagen-stimulated platelets from MI pre-treated with TLR4i showed a significant decrease of PA compared to platelets stimulated with collagen. Ex vivo study showed that TIRAP phosphorylation as well as TIRAP-MyD88 co-immunoprecipitation were higher in patients compared to controls. In vitro study showed that LPS, at concentrations like those found in MI, dose-dependently activated TIRAP and amplified the platelet response to the agonist, an effect blunted by TLR4i.

CONCLUSION

The study provides evidence that in MI patients platelet TLR4 is activated and suggests circulating LPS as potential trigger.

摘要

简介

血小板 toll 样受体 4（TLR4）在心肌梗死（MI）患者中过度表达，但仍需阐明其是否被激活以及潜在的触发因素。

方法

在体外研究了 40 名 MI 患者和 40 名年龄、性别和动脉粥样硬化危险因素匹配的对照者的血小板中，单独或联合使用 TLR4 抑制剂（TLR4i）时的脂多糖（LPS）血清水平和胶原诱导的血小板聚集（PA）；还通过 Western blot 和共免疫沉淀分别研究了血小板 TIR 域包含衔接蛋白（TIRAP）和 TIRAP-MyD88 相互作用。进行了体外实验以观察 LPS 是否触发血小板 TIRAP 磷酸化。

结果

与对照组相比，患者的血清 LPS 水平显著升高（29.5±7.1 比 16.2±3.8 pg/mL；p<0.001）。与用胶原刺激的 MI 预处理的 TLR4i 刺激的血小板相比，胶原刺激的血小板的 PA 明显降低。体外研究表明，与对照组相比，MI 患者的 TIRAP 磷酸化和 TIRAP-MyD88 共免疫沉淀均升高。体外研究表明，LPS 以类似于 MI 中发现的浓度，剂量依赖性地激活 TIRAP 并放大血小板对激动剂的反应，TLR4i 可减弱这种作用。