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Differential expression of functional nucleoside transporters in non-differentiated and differentiated human endothelial progenitor cells

2010; Elsevier BV; Volume: 31; Issue: 10 Linguagem: Inglês

10.1016/j.placenta.2010.07.016

1532-3102

Enrique Guzmán‐Gutiérrez, C. Sandoval, E. de Nova, Juan Luis Castillo, Juan Carlos Vera, Liliana Lamperti, Bernardo J. Krause, Carlos Salomón, Catarina Sepúlveda, Claudio Aguayo, Luis Sobrevía,

Renal Transplantation Outcomes and Treatments

Extracellular adenosine removal is via human equilibrative nucleoside transporters 1 (hENT1) and 2 (hENT2) in the endothelium, thus regulating adenosine-induced revascularization and angiogenesis. Since human endothelial progenitor cells (hEPCs) promote revascularization, we hypothesize differential expression of nucleoside transporters in hEPCs. hEPCs were cultured 3 (hEPC-3d) or 14 (hEPC-14d) days. RT-PCR for prominin 1, CD34, octamer-4, kinase insert domain receptor, oxidized low-density lipoprotein (lectin-like) receptor 1 and tyrosine endothelial kinase was used to evaluate phenotypic differentiation. Flow cytometry was used to estimate CD34+/KDR− (non-differentiated), CD34−/KDR+ (differentiated) or CD34+/KDR+ (mixed) cell populations. Adenosine transport was measured in absence or presence of sodium, S-(4-nitrobenzyl)-6-thio-inosine (NBTI, 1–10 μM), inosine, hypoxanthine or guanine (0.1–5 mM), hENTs protein abundance by western blot, and hENTs, hCNT1, hCNT2 and hCNT3 mRNA expression by real time RT-PCR. hEPC-3d cells were CD34+/KDR− compared with hEPC-14d cells that were CD34−/KDR+. hEPC-3d cells exhibit hENT1-like adenosine transport (NBTI-sensitive, Na+-independent), which is absent in hEPC-14d cells. hEPC-14d cells exhibit two transport components: component 1 (NBTI insensitive, Na+-independent) and component 2 (NBTI insensitive, Na+-dependent, Hill coefficient ∼1.8), the latter resembling CNT3-like transport. hEPC-3d cells express hENT1 protein and mRNA, which is reduced (∼90%) in hEPC-14d cells, but instead only hCNT3 mRNA is expressed in this cell type. hENT2, hCNT1 and hCNT2 were undetectable in hEPCs. Thus, hEPCs exhibit a differential expression of hENT1 and hCNT3 functional nucleoside transporters, which could be related with its differentiation stage.