Specific proteome changes in platelets from individuals with GATA1-, GFI1B-, and RUNX1-linked bleeding disorders.

Area of Science:

• Hematology
• Molecular Biology
• Proteomics

Background:

• Familial bleeding disorders are often caused by mutations in transcription factors like GATA1, GFI1B, and RUNX1.
• Mutant platelets share abnormalities, such as reduced α-granules, suggesting common deregulated pathways.

Purpose of the Study:

• To investigate and compare the full platelet proteomes in individuals with mutations in GATA1, GFI1B, or RUNX1.
• To identify common or distinct protein alterations caused by these different transcription factor mutations.

Main Methods:

• Label-free quantitative mass spectrometry was used to analyze platelet proteomes from 11 patients and 28 healthy controls.
• Proteomic data were analyzed using clustering to identify differentially expressed proteins.

Main Results:

• 2875 platelet proteins were quantified; over 300 were differentially expressed between cases and controls.
• While many proteins related to platelet function and hemostasis were downregulated, no single protein was consistently affected across all mutation types.
• No proteins were commonly overrepresented in all affected cases.

Conclusions:

• Mutations in GATA1, GFI1B, and RUNX1 lead to distinct, largely non-overlapping alterations in the platelet proteome.
• These findings provide a quantitative proteomic landscape of how these mutations impact platelet function in inherited bleeding disorders.