PB0861 - Endoplasmic Reticulum (ER) stress is increased in diabetic platelets and contributes to platelet hyperactivity

Monday, June 26, 2023

18:30 – 19:30 ET

Room: Exhibition

Presenting Author(s)

Yvonne X. Kong, FRACP, FRCPA, MBBS, MSc

PhD Candidate
Haematology Research Group, Charles Perkins Centre, University of Sydney
Camperdown, New South Wales, Australia

Co-Author(s)

RR

Rajan Rehan

Cardiologist
Department of Cardiology, Royal Prince Alfred Hospital
Sydney, New South Wales, Australia
FG

Fay Ghani

Research Assistant
Haematology Research Group, Charles Perkins Centre, University of Sydney
Sydney, New South Wales, Australia
JF

Jemma Fenwick

Research Assistant
Haematology Research Group, Charles Perkins Centre, University of Sydney
Sydney, New South Wales, Australia
DR

Declan Robertshaw

Medical Student
Sydney Medical School, University of Sydney
Sydney, New South Wales, Australia
VT

Vincent Trang

Medical Student
Sydney Medical School, University of Sydney
Sydney, New South Wales, Australia
SM

Soren Madsen

Postdoctoral Research Associate
David James Lab, Charles Perkins Centre, University of Sydney
Sydney, New South Wales, Australia
MP

Meg Potter

Research Assistant
David James Lab, Charles Perkins Centre, University of Sydney
Sydney, New South Wales, Australia
KC

Kristen Cooke

Team Leader of General Research Activities
David James Lab, Charles Perkins Centre, University of Sydney
Sydney, New South Wales, Australia
JS

Jacqueline Stoeckli

Group Leader
Molecular Cell Biology, School of Life and Environmental Sciences, University of Sydney
Sydney, New South Wales, Australia
GM

Grant Morahan

Group Leader
Cardiovascular Science and Diabetes Program, Harry Perkins Institute of Medical Research, Western Australia
Perth, Western Australia, Australia
SC

Sian Cartland

Senior Postdoctoral Scientist
Vascular Complications Group, Heart Research Institute
Sydney, New South Wales, Australia
MK

Mary Kavurma

Group Leader
Vascular Complications Group, Heart Research Institute
Sydney, New South Wales, Australia
MC

Michelle Cielesh

Research Assistant
Larance Laboratory, Charles Perkins Centre, University of Sydney
Sydney, New South Wales, Australia
YZ

Yunwei Zhang

PhD Candidate
Sydney Precision Bioinformatics, University of Sydney
Sydney, New South Wales, Australia
JY

Jean Yang

Group Leader
Sydney Precision Bioinformatics, University of Sydney
Sydney, New South Wales, Australia
DJ

David James

Group Leader
David James Lab, Charles Perkins Centre, University of Sydney
Sydney, New South Wales, Australia
JW

James Weaver

Cardiologist
Department of Cardiology, Royal Prince Alfred Hospital
Sydney, New South Wales, Australia
ML

Mark Larance

Group Leader
Larance Laboratory, Charles Perkins Centre, University of Sydney
Sydney, New South Wales, Australia
FP

Freda Passam

Group Leader
Haematology Research Group, Charles Perkins Centre, University of Sydney
Sydney, New South Wales, Australia

Background: Platelets from patients with diabetes mellitus (DM) are more prone to activate and contribute to the increased risk of cardiovascular events. Recently, endoplasmic reticulum (ER) stress has been implicated in platelet activation (1). We have shown knockout of an ER chaperone, ERp5, in megakaryocytes leads to platelet ER stress and increased thrombosis (2). The role of megakaryocyte or platelet ER stress in patients with established coronary artery disease (CAD) remains unknown (3).

Aims: To investigate ER stress pathways in platelets from patients with diabetes mellitus, the origin of platelet ER stress and its role in platelet activity.

Methods: Patients with or without type 2 diabetes mellitus (non-DM) were recruited before coronary angiography (DM = 42, non-DM = 34). Platelet proteins were identified by untargeted LC-MS/MS and Western blot. Femurs were isolated from a murine model of type 1 DM with hyperlipidaemia (ApoE-/- ± streptozotocin) and type 2 DM (outbred mice on high fat diet). ER proteins were visualised by immunofluorescence. Healthy donor platelets were treated with ER stress inducer thapsigargin. Platelet activation was assessed by CD62P mobilisation and PAC1 positivity.

Results: DM platelets were enriched for proteins involved in oxidative stress (e.g. GPX7) by proteomic analysis, and increased phospho-IRE1α (Figure 1B). These platelets also demonstrated greater CD62P mobilisation after submaximal thrombin (0.025U/mL) stimulation compared to non-DM. In both murine models, there was increased phospho-IRE1α in megakaryocytes from hyperglycaemic compared to normoglycaemic controls (Figures 1C and 1D). There was increased PERK pathway activation, indicated by phospho-eIF2α, only in megakaryocytes from the hyperglycaemic hyperlipidaemic ApoE-/- mice (Figure 1C). Thapsigargin treated healthy human platelets demonstrated IRE1 pathway activation, increased CD62P mobilisation and PAC1 positivity.

Conclusion(s): We propose physiological stressors such as hyperglycaemia and hyperlipidaemia can lead to ER stress in megakaryocytes. This ER stress signature is inherited by the platelets and primes them for subsequent activation.