Adenosine A2A receptors play an active role in mouse bone marrow-derived mesenchymal stem cell development

Bone marrow-derived mesenchymal stem cells (BM-MSCs) play a role in wound healing and tissue repair and may also be useful for organ regeneration. As we have demonstrated previously that A(2A) adenosine receptors (A(2A)R) promote tissue repair and wound healing by stimulating local repair mechanisms and enhancing accumulation of endothelial progenitor cells, we investigated whether A(2A)R activation modulates BM-MSC proliferation and differentiation. BM-MSCs were isolated and cultured from A(2A)-deficient and ecto-5'nucleotidase (CD73)-deficient female mice; the MSCs were identified and quantified by a CFU-fibroblast (CFU-F) assay. Procollagen alpha2 type I expression was determined by Western blotting and immunocytochemistry. MSC-specific markers were examined in primary cells and third-passage cells by cytofluorography. PCR and real time-PCR were used to quantitate adenosine receptor and CD73 expression. There were significantly fewer CFU-Fs in cultures of BM-MSCs from A(2A)R knockout (KO) mice or BM-MSCs treated with the A(2A)R antagonist ZM241385, 1 microM. Similarly, there were significantly fewer procollagen alpha2 type I-positive MSCs in cultures from A(2A)R KO and antagonist-treated cultures as well. In late passage cells, there were significantly fewer MSCs from A(2A) KO mice expressing CD90, CD105, and procollagen type I (P<0.05 for all; n=3). These findings indicate that adenosine and adenosine A(2A)R play a critical role in promoting the proliferation and differentiation of mouse BM-MSCs.