The effects of ROS-mediating oxygen tension on human CD34(+)CD38(-) cells induced into mature dendritic cells.

Oxygen tension regulates the biological characteristics of hematopoietic stem and progenitor cells (HSPCs) by modulating intracellular reactive oxygen species (ROS). To better understand oxygen tension mechanism on HSPCs culture, gene expression analysis of human CD34(+)CD38(-) HSPCs was performed using microarrays. The CD34(+)CD38(-) HSPCs cultured under normoxia, hypoxia, or with N-acetyl cysteine (NAC, an ROS scavenger) were isolated for transcriptional profilings. Compared to normoxia group, 1 gene was up-regulated and 22 genes were down-regulated in hypoxia group, while 1 gene was up-regulated and 29 genes were down-regulated in NAC group. These differently expressed genes were involved in cell surface markers, blood activation and differentiation. The common down-regulated genes related to dendritic cells (DCs) maturation (CD80, CD86, and JAG1) were confirmed by real-time RT-PCR. Furthermore, the analysis of the phenotypes of DCs, including the DC-characteristic surface molecule CD1a, the costimulatory molecules CD80 and CD86, and HLA-DR, associated with the capacity of DCs to stimulate allogeneic T cells, showed that hypoxia-mediating ROS inhibited the potential of CD34(+)CD38(-) HSPCs differentiating to mature DCs. All these results demonstrated that hypoxia-reducing ROS down-regulated the genes driving CD34(+)CD38(-) HSPCs differentiation, which provides an interesting molecular hint to direct their development to DCs during cultures. Copyright Â