A Platform for Studying of the Three-Dimensional Migration of Hematopoietic Stem/Progenitor Cells

Abstract

BACKGROUND: Hematopoietic stem/progenitor cells (HSPCs) have the property to return to the bone marrow, which is believed to be critical in situations such as HSPC transplantation. This property plays an important role in the stemness, viability, and proliferation of HSPCs, also. However, most in vitro models so far have not sufficiently simulated the complicate environment. Here, we proposed a three-dimensional experimental platform for the quantitative study of the migration of HSPCs. METHODS: After encapsulating osteoblasts (OBs) in alginate beads, we quantified the migration of HSPCs into the beads due to the physical environment using digital image processing. Intermittent hydrostatic pressure (IHP) was used to mimic the mechanical environment of human bone marrow without using any biochemical factors. The expression of stromal cellderived factor 1 (SDF-1) under IHP was measured. RESULTS: The results showed that the presence of OBs in the hydrogel scaffold initiate the movement of HSPCs. Furthermore, the IHP promotes the migration of HSPCs, even without the addition of any biochemical factors, and the results were confirmed by measuring SDF-1 levels. CONCLUSION: We believe this suggested three-dimensional experimental platform consisting of a simulated in vivo physical environment and encapsulated OBs should contribute to in vitro migration studies used to investigate the effects of other external factors.

Application of Elevated Atmospheric Pressure and Hypoxia Enhance Pluripotency and Stem Cell Differentiation

“…We next evaluate the influence of elevated atmospheric pressure on mesoderm lineage commitment. Physical force in the form of shear stress has been leveraged to enhance ESC differentiation to endothelial progenitor and hematopoietic lineages (Wolfe and Ahsan, 2013), and a combination of osteoblasts and intermittent hydrostatic pressure has been used to show an influence on HSPC migration (Kim et al, 2019; Lee et al, 2020), however no studies have implemented hydrostatic pressure to generate HSPCs from pluripotent stem cells on their own. We differentiated iPSCs to HSPCs expressing CD34, CD43, and CD45 using a bi-phasic oxygen concentration protocol to simulate in-vivo HSPC development.…”

Biomechanical cues as master regulators of hematopoietic stem cell fate

“…By seeding cells on a stretchable micropost array (SµPA) cytometry, Weng et al employed varying degrees of defined static equibiaxial cell stretches [163]. Alginate beads with osteoblasts encapsulated were used to bio-mimic the low 3D stiffness of the BM niche [209]. The application of intermittent hydrostatic pressure (IHP) also is a widely used approach to simulate the BM mechanical microenvironment [69,209,210].…”

Endogenous Stem Cell‐Based In Situ Tissue Regeneration Using Electrostatically Interactive Hydrogel with a Newly Discovered Substance P Analog and VEGF‐Mimicking Peptide

“…Several scaffolds can be loaded with SP1 or SP as chemoattractants to guide endogenous stem cells to the site of injury. [16][17][18][19] To apply the newly discovered SP1 in regenerative medicine, an electrostatically interactive hydrogel was used as a scaffold to load SP1.…”

“…Some in vivo studies have reported that SP scaffolds synergistically increase the migration of endogenous stem cells toward the scaffold. [16][17][18][19] Among the many types of scaffolds developed thus far, injectable hydrogels are widely used in tissue engineering due to the advantages of being in a liquid state before injection. Therefore, various physiologically active substances can be easily mixed into the hydrogel and injected in a noninvasive fashion without the need for surgery.…”