Primary Mesenchymal Stem and Progenitor Cells from Bone Marrow Lack Expression of CD44 Protein

Abstract

Background:The natural phenotype of mesenchymal stem cells (MSCs) has not been well characterized. Results: MSCs from bone marrow naturally are CD44 Ϫ ; however, in vitro cultivation results in acquisition of CD44 expression

The Human Mesenchymal Stem Cells and the Chick Embryo Chorioallantoic Membrane: The Key and the Lock in Revealing Vasculogenesis

“…CD44 is a well-described adhesion molecule existing in different isoforms that interact with multiple ligands, such as hyaluronan, selectins, collagen and fibronectin, but the functional consequence for acquisition of CD44 expression on the expanded MSC during therapeutic use remains unclear (9). Qian et al provide functional and molecular evidence suggesting that MSC physiologically do not express CD44 in both humans and mice and confirm that in vitro culture could result in acquisition of CD44 expression on their surface and changes in the expression of cytokines, growth factors, matrix proteins and other signaling molecules (9). In this context, the absence of the CD44 expression in MSC, after implantation onto CAM, represents a proof that MSC regain their precultivation CD44 status when they re-enter the in vivo medium.…”

Nonadherent culture method downregulates stem cell antigen-1 expression in mouse bone marrow mesenchymal stem cells

“…As previous research has shown, CD44 -MSCs exhibit similar properties to MSCs (12). Thus, to analyze Sca-1 expression, the CD45 -CD31 -CD44 -Sca-1 + MSCs were sorted.…”

“…Animal experimental protocols were performed with approval from the Local Ethics Committee at Karolinska Institute. Mononuclear cells were isolated from the BM of the mice using a previously described method (12). Briefly, femurs, tibias and iliac crests were crushed in Dulbecco's phosphate-buffered saline (DPBS; Gibco Life Technologies, Paisley, Scotland) and 10% fetal bovine serum (FBS; #10500064; Gibco Life Technologies, Divinopolis, Brazil).…”

“…In a previous study, CD44 -MSCs were determined to have properties of MSCs (12). Therefore, BM CD45 -CD31 -CD44 -Sca-1 + MSCs were selected for the study.…”

“…In addition, the in vitro conditions of the adherent culture may play a vital role in determining the stem cell niche; thus, may affect MSCs. A previous study revealed that CD44 -BM cells contained almost all clonogenic cells with a multilineage differentiation potential (12). However, in vitro culture of CD44 -BM cells resulted in their conversion to a CD44 + phenotype.…”