Space constraints govern fate of hematopoietic stem and progenitor cells in vitro

Datum

30.10.2014

Zeit

14:30 - 16:00

Sprecher

M.Sc. Eike Müller

Zugehörigkeit

Leibniz Institute of Polymer Research Dresden

Serie

IMB - Seminar

Sprache

de

Hauptthema

Biologie

Andere Themen

Biologie

Beschreibung

The combinational interplay of constitution, topology and spatial constraints of the extracellular microenvironment have been shown to tightly regulate hematopoetic stem cell (HSC) function and fate. Therefore, bioengineered and micropatterened platforms are developed to recapitulate key stem cell niche parameters in vitro.1 Microcavity arrays can be instrumental for presenting defined spatial constraints, adhesion ligands, growth factors, and stiffness. Our approach aimed on mimicking bone marrow parameters including hydration, porosity, and the function of glycosaminoglycans, which bind and present various growth factors. We use a new reliable method to create microcavity arrays made of polyethylene glycol - heparin hydrogels with microcavity aspect ratios ranging from single- to multi-cell capacities.2 The heparin functionality allowed to modulate growth factor presentation. The microstructured hydrogel scaffolds were compared to fibronectin functionalized micropatterned silicone scaffolds in cell culture of human (CD34+) hematopoietic stem and progenitor cells (HSPC). We investigated the impact of spatial confinement by the cavities, as well as fibronectin and heparin functionalization upon HSPC cycling, differentiation, and growth factor expression. Independent of material properties, we observed reduced HSPC expansion within microcavities hosting individual cells compared to larger cavities or planar scaffolds, indicating a more quiescent state within the small cavities. Based on growth factor screening experiments, we could dissect the impact of autocrine and paracrine signaling of IL12, HGF, RANTES, and VEGF in a partial least square analysis using a simple mechanistic model. In conclusion, our matrix-inspired microcavity scaffolds provide an approach to reveal important signaling mechanisms in HSPC expansion. This should allow for further studies on the dynamic nature of HSC fate decisions in vitro and provide new insights in the in vivo regulation in the bone marrow. 1. Kurth, I., et al. Hematopoietic stem and progenitor cells in adhesive microcavities. Integr. Biol. 1, 427–34 (2009). 2. Tsurkan, M. V. et al. Defined Polymer-Peptide Conjugates to Form Cell-Instructive starPEG-Heparin Matrices In Situ. Adv. Mater. 25, 2606–10 (2013).

Letztmalig verändert: 24.10.2014, 13:12:36