GSDME-mediated pyroptosis contributes to chemotherapy-induced platelet hyperactivity and thrombotic potential

Medicine Life Sciences Biochemistry Cell Biology Hematology
platelets pyroptosis chemotherapy thrombosis GSDME caspase-3 membrane pore formation

Background Introduction

Chemotherapy has long been a cornerstone of cancer treatment but is accompanied by significant side effects. Among cancer patients receiving platinum-based chemotherapy drugs (e.g., cisplatin), the incidence of thromboembolic events significantly increases, including pulmonary embolism, cerebrovascular incidents, angina, and myocardial infarction. Moreover, chemotherapy-associated arterial and venous thrombosis often directly correlate with patient mortality. Studies have shown that cisplatin chemotherapy can elevate the risk of venous thromboembolism (VTE) by more than 6.5-fold, which has been confirmed across various types of cancers. However, the specific mechanisms by which chemotherapy contributes to thrombosis formation remain incompletely understood.

Platelets play a central role in thrombosis, and increased platelet reactivity has been observed in chemotherapy patients. Cell death processes such as apoptosis and pyroptosis under chemotherapy have gained increasing attention. Pyroptosis is a newly identified form of programmed cell death executed by the gasdermin (GSDM) family, particularly GSDME, a critical member associated with chemotherapy-induced cell death in various tissues like the spleen, kidney, and small intestine. However, whether GSDME mediates platelet pyroptosis and whether this pyroptosis is linked to the increased thrombotic risk in chemotherapy patients remain unaddressed.

This study aims to determine whether GSDME contributes to platelet hyperactivity and thrombotic potential through chemotherapy-induced platelet pyroptosis.

Summary of the Article

This research, conducted by Ruyi Xue, Min Li, Ge Zhang, and their team, is affiliated with the Department of Biochemistry and Molecular Biology at the Basic Medical Sciences School of Fudan University and the Zhongshan Hospital of Fudan University. The study was published in the journal Blood, under the title “GSDME-mediated pyroptosis contributes to chemotherapy-induced platelet hyperactivity and thrombotic potential.”

Research Process and Experimental Design

The paper is based on a single original study and includes the following key steps:

1. Evaluating the Functional Expression of GSDME in Platelets

Through reverse transcription-PCR and immunoblotting, the research examined GSDME expression at the mRNA and protein levels in human and mouse platelets to verify its functional presence. Results showed that GSDME is expressed in platelets and their precursor megakaryoblast cell lines (e.g., Meg-01), and the expression was not due to contamination by leukocytes.

2. Chemotherapy Drugs Induce GSDME-Mediated Pyroptosis in Platelets

By treating platelets with cisplatin and etoposide, it was found that GSDME is cleaved by caspase-3 to produce its N-terminal fragment (GSDME-N). GSDME-N forms pores on platelet membranes, resulting in bubble-like morphology and granule release, leading to platelet overactivation. Similar results were observed in megakaryoblasts and patient platelets after chemotherapy.

3. Exploring the Role of GSDME in Platelet Function and Thrombosis Formation

Using mouse models, the platelet function in wild-type (WT) mice was compared with GSDME knockout (GSDME−/−) mice. Results demonstrated that GSDME−/− mice exhibited significantly reduced platelet aggregation, granule release, and thrombus formation in vitro and in vivo.

4. Molecular Mechanistic Exploration of Risk Pathways

Through co-immunoprecipitation and mass spectrometry, Flotillin-2, a crucial lipid raft scaffolding protein, was identified as an interactor with GSDME-N. Flotillin-2 recruits GSDME-N to membrane lipid rafts, facilitating pore formation during pyroptosis. Site-directed mutagenesis and structural modeling confirmed the binding domains for GSDME and Flotillin-2 during this interaction.

5. Clinical Implications

Twenty hepatobiliary cancer patients undergoing cisplatin-based chemotherapy were included, with blood samples collected before and 24 hours after treatment. Post-therapy samples revealed elevated platelet aggregation, granule release, and upregulated GSDME-N expression, further validating the mechanism in patient platelets.

Research Results

The study outlined the following key findings:

  1. Functional Expression of GSDME in Platelets: This study was the first to confirm the functional expression of GSDME in platelets and its activation by chemotherapy-induced pyroptosis.

  2. Cisplatin Activates Caspase-3 to Trigger GSDME-Mediated Pyroptosis: Dose- and time-dependent GSDME cleavage was observed in platelets treated with cisplatin or etoposide, both in vitro and in vivo.

  3. GSDME Deficiency Reduces Platelet Function and Thrombotic Potential: GSDME−/− mice exhibited impaired platelet granule release, reduced aggregation, morphological changes, prolonged time for thrombus formation, and diminished clot formation in vivo.

  4. Flotillin-2 Recruits GSDME-N to Membrane Lipid Rafts: Flotillin-2 was identified as an essential protein recruiting GSDME-N to lipid rafts on the platelet membrane, where it facilitates pore formation and subsequent granule release.

  5. Clinical Relevance: Enhanced platelet activity and GSDME-mediated pyroptosis were validated in patients undergoing cisplatin chemotherapy.

Significance and Value of the Research

  1. Scientific Contribution: This study identifies a novel mechanism—GSDME-mediated platelet pyroptosis—that links chemotherapy to platelet hyperactivation and thrombotic risk.

  2. Clinical Implications: Targeting the GSDME pyroptotic pathway could help mitigate thrombosis risk in chemotherapy patients, offering a safer adjunctive therapy during cancer treatment.

  3. Methodological Innovation: The study employed advanced techniques, including high-throughput mass spectrometry, 3D structural modeling, and lipid raft manipulations, to elucidate a novel mechanism of platelet function regulation.

  4. Correlation with Patient Outcomes: The study included 20 matched patient samples, demonstrating the clinical relevance of the proposed mechanism and bridging basic science with clinical applications.

Conclusion

This study systematically elucidates how cisplatin induces platelet pyroptosis through the Caspase-3/GSDME axis, leading to platelet hyperactivity and increased thrombotic potential. It identifies GSDME as a crucial regulator of platelet abnormality during chemotherapy and unveils Flotillin-2’s role in the membrane transposition of GSDME-N. Targeting the GSDME-mediated pyroptotic pathway may provide new avenues to prevent thrombosis-related complications commonly observed in cancer patients undergoing chemotherapy. This work provides an essential basis for optimizing patient safety and individualizing cancer therapy while expanding the understanding of pyroptosis in different cellular contexts and functions.