- Letter to the Editor
- Open Access
SARS-CoV-2 interacts with platelets and megakaryocytes via ACE2-independent mechanism
Journal of Hematology & Oncology volume 14, Article number: 72 (2021)
Evidence suggests that platelets may directly interact with SARS-CoV-2, raising the concern whether ACE2 receptor plays a role in this interaction. The current study showed that SARS-CoV-2 interacts with both platelets and megakaryocytes despite the limited efficiency. Abundance of the conventional receptor ACE2 and alternative receptors or co-factors for SARS-CoV-2 entry was characterized in platelets from COVID-19 patients and healthy persons as well as human megakaryocytes based on laboratory tests or previously reported RNA-seq data. The results suggest that SARS-CoV-2 interacts with platelets and megakaryocytes via ACE2-independent mechanism and may regulate alternative receptor expression associated with COVID-19 coagulation dysfunction.
To the editor
Associated with coagulative disorders, COVID-19 patients have increased platelet activation and aggregation, and platelet-monocyte aggregation [1,2,3], which highlights the critical role of platelets in SARS-CoV-2 infection and immunopathology . Consistent with previous reports [1,2,3], our retrospective survey of plasma samples from a cohort of 62 cases (severe or fatal and moderate COVID-19 patients, Additional file 1: Table S1) showed that COVID-19 was associated with mild thrombocytopenia (platelet count < 150 × 109/L) and increased thrombosis (elevated D-dimer levels), and patients had increased platelet activation (elevated sP-selectin and sGPVI levels) and cytokine (PF4 and RANTES) release upon platelet activation (Fig. 1a). Direct interaction of SARS-CoV-2 with human platelets was suggested based on increased P-selectin translocation on platelet surface (Fig. 1b), and elevated levels of GPVI, PF4, and RANTES in platelet culture supernatants (Fig. 1c). However, the characteristics and mechanisms of the direct interaction between SARS-CoV-2 and platelets are not well elucidated, and the role of platelet receptors in the interaction remains to be clarified [4, 5].
SARS-CoV-2 infection in human platelets and its progenitor megakaryocyte cell line MEG-01 in vitro was subsequently characterized. SARS-CoV-2 N expression was observed in some platelets and MEG-01 cells (Fig. 2a). SARS-CoV-2 RNA was detected in both culture supernatant and MEG-01 cells after SARS-CoV-2 incubation and could be maintained with a slight increase until 48 h p.i. (Fig. 2b). This suggests that SARS-CoV-2 may infect and replicate in megakaryocytes despite insufficient efficiency. However, we failed to observe any viral particles in MEG-01 cells through electron microscopy, probably because of using insufficient dose of viruses (1 MOI) for incubation, or limited infection in MEG-01 cells, as indicated by IFA images. SARS-CoV-2 RNA copies were lower in platelets (10–102 copies/103 cells) and culture supernatant (103–104 copies/mL), which diminished after 12 h (data not shown). Therefore, we speculate that platelets may not support SARS-CoV-2 replication. This echoes recent studies which have shown that SARS-CoV-2 entry in platelets may not be common in COVID-19 patients: SARS-CoV-2 RNA was detected in platelets from a few severe (2/25, 8% ; 2/11, 18.2% ) and non-severe (9/38, 23.7% ) patients and was not detected in platelets from patients (0/24 ).
The evidence of direct interaction between SARS-CoV-2 and platelets or megakaryocytes raised the concern whether ACE2 plays a role in the process. The IFA and western blot assays showed a lack of ACE2 expression in both human platelets and megakaryocytes (Fig. 2c, d). The RNA abundance of 14 receptors or co-factors including ACE2 in human platelets and megakaryocytes was subsequently inspected based on RNA-seq data reported in previous studies [2, 8] (Additional file 1: Table S2 and S3). As summarized in Fig. 2e, the abundance order in platelets was: CD147 > GRP78 > KREMEN1 > ADAM17 > cathepsin L > NRP1 > ASGR1 > CD209L/L-SIGN > CD301 > CD26 > CD206, but CD209/DC-SIGN, ACE2, and TMPRSS2 were not identified. Human megakaryocytes had similar receptor profiles, coupled with the detection of CD209/DC-SIGN. We also verified receptor abundance in MEG-01 and human platelets using qRT-PCR. In MEG-01 cells, CD147, GRP78, KREMEN1, cathepsin L, NRP1, and ASGR1 were detected, while in platelets, CD147, GRP78, KREMEN1, and ASGR1 were detected. ACE2 was not detected in MEG-01 cells or platelets (Fig. 2f). These results indicate that SARS-CoV-2 may use receptors other than ACE2 to interact with platelets or megakaryocytes.
Further analysis using the RNA-seq data showed unchanged GRP78, ADAM1, cathepsin L, GRP1, and ASGR1 abundance in platelets between ICU and non-ICU COVID-19 patients and healthy persons and revealed elevated CD147 and KREMEN1 levels and reduced NRP1 levels in patients (Fig. 2g). This was also observed in MEG-01 cells with increased CD147 and KREMEN1 levels and slightly reduced NRP1 levels after SARS-CoV-2 incubation (Fig. 2h). These data suggest that SARS-CoV-2 infection may alter gene transcription in platelets and megakaryocytes, which is similar to DENV infection that markedly changes the platelet and megakaryocyte transcriptome .
Owing to their roles in binding to spike protein and facilitating virus entry [9,10,11], CD147, KREMEN1, and NRP1 triggering of SARS-CoV-2 entry in human platelets and megakaryocytes requires in-depth investigation. Moreover, based on the original functions of CD147 in signaling pathways via cell–cell interactions  and of NRP1 in cardiovascular, neuronal, and immune systems , SARS-CoV-2 interaction with platelets is suspected to regulate platelet-mediated immune response  and promote coagulation dysfunction in COVID-19 .
Availability of data and materials
All data generated or analyzed during this study are included in this published article (and its supplementary information files).
Coronavirus disease 2019
Severe acute respiratory syndrome coronavirus
- SARS-CoV-2 N:
Angiotensin-converting enzyme 2
Soluble glycoprotein VI
Platelet factor 4
C-C motif chemokine ligand 5, CXCL5
Glucose regulating protein 78
Kringle containing transmembrane protein 1
A disintegrin and metalloproteinase 17
Asialoglycoprotein receptor 1
C-type lectin domain family 4, member M, CLEC4M
C-type lectin domain containing 10A, CLEC10A
Dipeptidyl peptidase 4, DPP4
Macrophage mannose receptor, MMR
Dendritic cell (DC)-specific intracellular adhesion molecule 3 (ICAM-3)-grabbing non-integrin
Transmembrane serine protease 2
Quantitative reverse transcription-polymerase chain reaction
Multiplicity of infection
- h p.i.:
Hottz ED, Azevedo-Quintanilha IG, Palhinha L, Teixeira L, Barreto EA, Pão CRR, et al. Platelet activation and platelet-monocyte aggregates formation trigger tissue factor expression in patients with severe COVID-19. Blood. 2020;136:1330–41.
Manne BK, Denorme F, Middleton EA, Portier I, Rowley JW, Stubben CJ, et al. Platelet gene expression and function in patients with COVID-19. Blood. 2020;136:1317–29.
Middleton EA, He XY, Denorme F, Campbell RA, Ng D, Salvatore SP, et al. Neutrophil extracellulartraps (NETs) contribute to immunothrombosis in COVID-19 acute respiratory distress syndrome. Blood. 2020;136:1169–79.
Koupenova M, Freedman JE. Platelets and COVID-19: Inflammation, hyperactivation and additionalquestions. Circ Res. 2020;127(11):1419–21.
Campbell RA, Boilard E, Rondina MT. Is there a role for the ACE2 receptor in SARS-CoV-2 interactions with platelets? J Thromb Haemost. 2021;19(1):46–50.
Zaid Y, Puhm F, Allaeys I, Naya A, Oudghiri M, Khalki L, et al. Platelets can associate with SARS-Cov-2 RNA and are hyperactivated in COVID-19. Circ Res. 2020;127(11):1404–18.
Bury L, Camilloni B, Castronari R, Piselli E, Malvestiti M, Borghi M, et al. Search for SARS-CoV-2 RNA in platelets from COVID-19 patients. Platelets. 2021;32(2):284–7.
Campbell RA, Schwertz H, Hottz ED, Rowley JW, Manne BK, Washington AV, et al. Human megakaryocytes possess intrinsic antiviral immunity through regulated induction of IFITM3. Blood. 2019;133(19):2013–26.
Wang K, Chen W, Zhang Z, Deng Y, Lian JQ, Du P, et al. CD147-spike protein is a novel route for SARS-CoV-2 infection to host cells. Signal Transduct Target Ther. 2020;5(1):283.
Mayi BS, Leibowitz JA, Woods AT, Ammon KA, Liu AE, Raja A. The role of Neuropilin-1 in COVID-19. PLOS Pathog. 2021;17(1):e1009153.
Gu Y, Cao J, Zhang X, Gao H, Wang Y, Wang J, et al. Interaction network of SARS-CoV-2 with host receptome through spike protein. bioRxiv-Microbiol;2020. https://doi.org/10.1101/2020.09.09.287508
Savla SR, Prabhavalkar KS, Bhatt LK. Cytokine storm associated coagulation complications in COVID-19 patients: Pathogenesis and Management. Expert Rev Anti Infect Ther. 2021. https://doi.org/10.1080/14787210.2021.1915129.
We acknowledge Mr. Ding Gao, Ms. Anna Du, Ms. Juan Min, Ms. Pei Zhang, and Ms. Bichao Xu from the Core Facility and Technical Support Facility of the Wuhan Institute of Virology for their technical assistance. We thank Mr. Jia Wu, Mr. Hao Tang, and Mr. Jun Liu from the team of BSL-3 Laboratory of Wuhan Institute of Virology for their critical support in experimental activities, and Ms. Min Zhou and Mr. Zhong Zhang for their help with cell culture.
This work was supported by the National Natural Science Foundation of China (U20A20135), the National Program on Key Research Project of China (2018YFE0200402, 2019YFC1200701, and 2020YFC0845801), and the Fundamental Research Funds for the Central Universities (2020kfyXGYJ016).
Ethics approval and consent to participate
The study protocol was approved by the Ethics Committee of Tongji Medical College, Huazhong University of Science and Technology (number: 2020/0042–02-02).
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The authors declare that they have no competing interests.
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Shen, S., Zhang, J., Fang, Y. et al. SARS-CoV-2 interacts with platelets and megakaryocytes via ACE2-independent mechanism. J Hematol Oncol 14, 72 (2021). https://doi.org/10.1186/s13045-021-01082-6
- Platelet activation
- Alternative receptors