Abstract Number: PB1616
Meeting: ISTH 2020 Congress
Background: SRC is a non-receptor tyrosine kinase protein that phosphorylates specific tyrosine residues in other proteins upon activation. A germline heterozygous gain-of-function E527K variant in SRC was previously found to cause thrombocytopenia and bleeding in patients from two unrelated families.1,2 These patients also presented syndromic features such as myelofibrosis, osteoporosis, premature edentulism, behaviour problems and mild facial dysmorphia. Cellular studies showed that SRC-E527K resulted in hyperactive SRC signaling with increased overall tyrosine phosphorylation patterns. Platelets from patients are larger with a paucity of alpha-granules. The expression of lentiviral SRC-E527K in healthy CD34+ hematopoietic stem cells (HSC) was shown to decrease proplatelet formation during megakaryopoeisis in contrast to SRC-WT.
Aims: Our aim is to study the effect of SRC-E527K during megakaryopoiesis as it remains unknown how this kinase influences megakaryocyte (MK) differentiation.
Methods: SRC-WT and SRC-E527K lentiviral transduced MK were subjected to RNAseq and proteomics.
Results: RNAseq of day 12 differentiated MK derived from healthy CD34+ HSC transduced with SRC-WT versus SRC-E527K showed 691 significant differentially expressed genes (44% upregulated and 56% downregulated). Proteomic analysis of these MK cultures shows 141 significant differentially expressed proteins (29,8% upregulated and 70,2% downregulated) and alterations in 45 tyrosine phosphorylation sites were detected in 37 proteins. A combined analysis identified 20 upregulated genes/proteins versus 24 downregulated genes/proteins downregulated in SRC-E527K MK. A pathway analysis of these hits revealed a major role of interferon-stimulated proteins in hyperactive SRC signaling during megakaryopoiesis (p=2.35E-14).
Conclusions: The interferon pathway and other interesting candidate proteins will be further validated in MK generated from control, patient and patient-corrected inducible pluripotent stem cell models that have been generated.
1Turro E et al. (2016) Science Translational Medicine
2De Kock L et al. (2019) Platelets
To cite this abstract in AMA style:De Kock L, Thys C, Van Geet C, Freson K. Hyperactive SRC Kinase Results in Inherited Thrombocytopenia: Transcriptomics and Proteomics to Delineate the Defect in Megakaryopoiesis [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/hyperactive-src-kinase-results-in-inherited-thrombocytopenia-transcriptomics-and-proteomics-to-delineate-the-defect-in-megakaryopoiesis/. Accessed September 29, 2023.
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