Characterization of the interactions between stromal and haematopoietic progenitor cells in expansion cell culture models

Abstract

Development of the long-term culture models of haematopoietic stem cells (HSCs) is one of the important tasks in modern biotechnology. It has been suggested that stromal presence is important for haematopoiesis in vitro and in vivo, but the question remains: whether diffusible factors produced by stromal cells are sufficient for the regeneration of primitive and definitive haematopoietic cells, or direct cell-to-cell contacts of the cultured material with underlying stromal base would be required. During present studies, influence of various feeder layers and feeder layer conditioned media on proliferative, differentiative and clonogenic activity of human AC133+ derived from human umbilical cord blood was investigated. Cell extracts for feeder layers were prepared from 4-6 weeks old human embryos and co-cultured feeder cells. Effects of the conditioned media were also determined. Culture and feeder layer media were additionally supplemented with commonly implemented factors such as GM-CSF, IL-3 and LIF. Estimation of morpho-functional properties of AC133+ cultivated suspension cultures was performed in subculture experiments using semisolid agar culture conditions. Multipotential CFU-MIX (CFU-GEMM) and unipotential progenitor cells CFU-GM, BFU-E and CFU-E were observed and analyzed. Our data suggest that haematopoiesis can be sustained for prolonged cultivation periods in the presence of feeder layer cells or conditioned media supported culture models. Prolonged support of primitive haematopoietic cells and their clonogenic capacity and functional characteristics in feeder layer positive cultures, indicates that diffusible factors are sufficient for haematopoiesis and suggests that direct cell-to-cell contacts may not be exclusively required for successful long-term in vitro haematopoiesis.

Characterization of two distinct liver progenitor cell subpopulations of hematopoietic and hepatic origins

“…However, a distinct cell subpopulation retained the ability to propagate in the presence of iMEFs, a prerequisite shared by several hepatic progenitor as well as hematopoietic stem cell lines expressing c-kit and/or Thy1 [46,48,49]. Consistent with the latter, c-kit and Thy1 mRNA were detected in cell clusters, suggesting that these were derived from c-kit-positive HSCs.…”

Review:Ex VivoEngineering of Living Tissues with Adult Stem Cells

“…Endothelial cells stimulate murine neural stem cell self-renewal even when a Transwell membrane separates the 2 cell types, 78 and medium conditioned using human stromal cells supports hematopoiesis. 79 These experiments demonstrate that paracrine signaling molecules can alter stem cell fate. Injured tissue also releases soluble factors that TISSUE ENGINEERING WITH ADULT STEM CELLS trigger stem cell mobilization and proliferation.…”

Radiobiological Characterization Environment Around Object "Shelter"

“…For the determination of the distant intercellular transfer of the post-radiation signals between the cells of irradiated animals a novel method of in vivo culture using diffusion capsules (DC) was described [Bilko N.M., Votyakova I.A., Vasylovska S.V., 2005]. Investigations were done of the Balb/c mice ( Figure 32).…”