Cell mechanics of megakaryocytes in 3D tissues - deciphering mechanobiology of platelet formation

ongoing

Homeostatic platelet counts are crucial for vascular integrity and vital to life. Megakaryocytes (MEKs) are giant hematopoietic cells forming large protrusions that fragment to constantly replenish the circulating platelet pool. Nevertheless, severe blood loss, sepsis and aggressive cancer therapies, often cause critically low platelet levels - a major public health problem in Europe's aging population. Despite the unmet clinical need to control platelet production, there is a major lack of knowledge about the mechanistic cell biology of MEKs, hampering the development of innovative therapies. MEKanics will go beyond the state of the art and proposes a combined cell biological and biophysical approach to study MEKs in physiological tissue environments to uncover the mechanical principles that drive platelet formation. I will use quantitative microscopy to characterize cytoskeletal dynamics of MEKs confined in 3D environments of controlled adhesiveness, geometry and stiffness to reveal the mechanisms of force generation and transmission critical for MEK protrusion formation. Further, I will explore how protrusion mechanics affect cytoplasmic transport and partitioning of organelles required for functional platelets. Using super-resolution intravital imaging, I will investigate these processes in their physiological bone marrow niche. By integrating scRNAseq and live-cell microscopy, I will map morpho-dynamics with transcriptomics to identify the gene signature initiating protrusion formation of MEKs in response to mechanical stimuli. A novel MEK cell-system with optimized access to genetic manipulations will allow high-throughput screening of candidate genes. Together, the unique combination of genetics, engineering, quantitative microscopy and intravital tools will provide a holistic cell mechanical model of MEKs in 3D tissues paving the way for new therapeutic approaches to control platelet formation and to advance devices for large-scale platelet production.