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

Francesco Barillà; Vittoria Cammisotto; Simona Bartimoccia; Lorenzo Loffredo; Cristina Nocella; Noemi Bruno; Concetta Torromeo; Paolo Rosa; Nicola Viceconte; Pasquale Pignatelli; Carlo Gaudio; Roberto Carnevale; Francesco Violi

doi:10.1016/j.thromres.2021.11.019

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

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

Authors

Affiliations

¹ Department of Clinical Internal, Anaesthesiological and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy. Electronic address: francesco.barilla@uniroma1.it.
² Department of General Surgery and Surgical Speciality Paride Stefanini, Sapienza University of Rome, Rome, Italy. Electronic address: vittoria.cammisotto@uniroma1.it.
³ Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Italy. Electronic address: simona.bartimoccia@uniroma1.it.
⁴ Department of Clinical Internal, Anaesthesiological and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy. Electronic address: lorenzo.loffredo@uniroma1.it.
⁵ Department of Clinical Internal, Anaesthesiological and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy. Electronic address: cristina.nocella@uniroma1.it.
⁶ Department of Clinical Internal, Anaesthesiological and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy. Electronic address: n.bruno@uniroma1.it.
⁷ Department of Clinical Internal, Anaesthesiological and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy. Electronic address: concetta.torromeo@uniroma1.it.
⁸ Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Italy.
⁹ Department of Clinical Internal, Anaesthesiological and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy. Electronic address: nicola.viceconte@uniroma1.it.
¹⁰ Department of Clinical Internal, Anaesthesiological and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy; Mediterranea Cardiocentro, Napoli, Italy. Electronic address: pasquale.pignatelli@uniroma1.it.
¹¹ Department of Clinical Internal, Anaesthesiological and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy. Electronic address: carlo.gaudio@uniroma1.it.
¹² Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Italy; Mediterranea Cardiocentro, Napoli, Italy. Electronic address: roberto.carnevale@uniroma1.it.
¹³ Mediterranea Cardiocentro, Napoli, Italy. Electronic address: francesco.violi@uniroma1.it.

PMID: 34856494
DOI: 10.1016/j.thromres.2021.11.019

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.

Keywords: Lipopolysaccharides; Myocardial infarction; Platelets; Thrombosis; Toll-like receptor 4.

MeSH terms

Blood Platelets
Humans
Lipopolysaccharides / pharmacology
Membrane Glycoproteins
Myocardial Infarction*
Receptors, Interleukin-1
Toll-Like Receptor 4*

Substances

Lipopolysaccharides
Membrane Glycoproteins
Receptors, Interleukin-1
Toll-Like Receptor 4