Preliminary Investigation about the Expression of G Protein-Coupled Receptors in Platelets from Patients with Chronic Immune Thrombocytopenic Purpura
Authors: Chunling He
Wenjun Yu
Daming Xu
Xianru Xu
Duanxu Wang
Jinfeng Qiu
Zewen Zhang
Long Xie
Jun Yin
Chengwei Xu
Journal: Acta Haematologica (2021)
Discipline: CLINICAL MEDICINE
Keywords: Chronic immune thrombocytopenic purpura; Flow cytometry; G protein-coupled receptors; Platelets.
Affiliations: Division of Urological Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China., Department of Clinical Laboratory Medicine, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China., Division of Hematology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China., Office of Medical Affairs Administration, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China., Division of Respirology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China., Department of Hemodialysis, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China., Department of Pathology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China., Division of Inventional Ultrasonic Therapeutics, The Second Affiliated Hospital of Shantou University Medical College, Shantou, China.

Abstract:  Objective: The objective of this study was to determine the expression of G protein-coupled receptors (GPCRs) in platelets from adult patients with chronic immune thrombocytopenic purpura (ITP). Methods: Peripheral blood samples were collected from 40 patients with chronic ITP in the Second Affiliated Hospital of Shantou University Medical College, and 40 peripheral blood samples from healthy volunteers were collected; expressions of the adenosine diphosphate receptors (P2Y1 and P2Y12), alpha-2A adrenergic receptor (Œ±2A-AR), and thromboxane A2 receptor (TP) in platelets were detected by flow cytometry. GŒ± protein, protease-activated receptor 1 (PAR1), and protease-activated receptor 4 (PAR4) were analyzed by Western blot and analyzed statistically. Results: Flow cytometry measurements of mean fluorescence intensities showed platelets from patients with chronic ITP, compared to healthy individuals, had significantly higher levels of P2Y1 (31.4 ¬± 2.2 vs. 7.8 ¬± 0.8), P2Y12 (29.6 ¬± 2.1 vs. 7.2 ¬± 1.3), Œ±2A-AR (25.8 ¬± 2.9 vs. 9.8 ¬± 0.9), and TP (39.8 ¬± 3.1 vs. 4.7 ¬± 0.6) (all p &lt; 0.01). Similarly, integrated optical density analysis of Western blots showed that platelets from patients with chronic ITP had significantly higher levels of GŒ± (1046.3 ¬± 159.96 vs. 254.49 ¬± 39.51), PAR1 (832.98 ¬± 98.81 vs. 203.92 ¬± 27.47), and PAR4 (1518.80 ¬± 272.45 vs. 431.27 ¬± 41.86) (all p &lt; 0.01). Conclusion: Expression of GPCRs is increased in platelets from patients with chronic ITP, suggesting that platelets of chronic ITP may participate in the complicated biological process by means of GPCR-mediated signaling pathways. 

Retracted: No

PubPeer comments:
 This recent paper by Xu et al. examines expression of the protease-activated receptors PAR1 and PAR4 in normal platelets and those from patients with chronic ITP. The primary comparison is shown in Figure 6 which presents an immunoblot analysis of platelet lysates:  This figure indicates total absence of PAR1 and PAR4, as well as G alpha subunits in normal platelets (Contr), which is inconsistent with the reported normal high level of expression of these proteins. Can the authors clarify? ,