Thesis defense Asena Abay

On 13 October 2021 (11:00 AM) Sanquin researcher Asena Abay defended her thesis 'Shaping erythropoiesis under in vitro flow' at the University of Amsterdam

Promotor
MM von Lindern PhD

Copromotores
E van den Akker PhD and prof L Kaestner PhD

Venue
Aula, University of Amsterdam and online

Summary

With the advancement of red blood cell (RBC) based regenerative therapies and the limitations of donor-dependent transfusions, there is an unmet medical need for large scale cultured RBCs. Such cultures can be achieved in bioreactor systems, where agitation and delivery of nutrients can be optimized. Culturing RBC precursors, erythroblasts, in a bioreactor would bring up new questions based on biomechanics and fluid dynamics, as well as physiological and transcriptional responses to repeated mechanical stress. We investigated the fixation of RBCs with glutaraldehyde, to be used as a diagnostic tool for morphological diseases or as non-deformable RBCs for biomechanical applications. We then employed a sudden constriction and expansion microchannel to resolve the cross-sectional flow profile of RBC. We revealed a unique geometry induced focusing near the wall regions post-constriction, and showed that non-deformable RBCs were more likely to be trapped in the vortices. These findings are applicable for designing cell separation/purification methods, alternative to slit-based filters. Next, our research expanded on Ca²⁺-dependent downstream signaling of erythroblasts, upon fluidic mechanical stress. We showed comparable signaling cascades following chemical activation of PIEZO1 and mechanical stimulation. We confirmed the Ca²⁺ dependence of these pathways by intracellular chelation of Ca²⁺. Additionally we investigated physiological and transcriptional responses to mechanical stress during terminal differentiation. We observed an accelerated maturation/enucleation of erythroblasts when cultured in a non-stationary setup. Taken altogether, our findings help the development of large scale erythroblast cultures by expanding the knowledge of physiological responses to fluidic stress and biomechanics of RBCs and erythroblasts.