Profiling of immune‐related microRNA expression in human cord blood and adult peripheral blood cells upon proinflammatory stimulation

Abstract

Cord blood (CB) transplantation has advantages in terms of incidence and severity of acute graft-versus-host disease (GVHD), while it has disadvantages in terms of infection. Our aim is to elucidate the molecular mechanism underlying the immune response of CB-derived cells during acute GVHD and infection following CB transplantation. We examined expression of 69 immune-relating microRNAs in CD4(+), CD8(+), and CD14(+) cells of CB and adult peripheral blood (APB) upon interferon-γ or lipopolysaccharide (LPS) stimulation. Under basal condition, 20 microRNAs showed differential expression between CB and APB. Compared to APB counterparts, six microRNAs (miR-21, miR-22, miR-29a, miR-29b, miR-29c, and let-7c) were underexpressed in at least two cell lineages of CB, while five microRNAs (miR-15b, miR-181a, miR-181c, miR-363, and miR-424) were overexpressed in CD4(+) and CD8(+) CB cells. Upon interferon-γ stimulation, seven microRNAs (miR-29a, miR-29b, miR-34c-5p, miR-132, miR-146a, miR-146b-5p, and miR-155) changed in expression mainly in CD14(+) CB cells, while only two microRNAs (miR-18a and miR-155) changed in expression in CD14(+) CB cells upon LPS stimulation. These results suggest that the mechanisms regulating the expression of such immune-relating microRNAs in CD14(+) CB cells are much more sensitive to proinflammatory stimuli than those in APB CD14(+) cells, which might be related to the poor immunoreactivity of CD14(+) CB cells. Our results suggest essential roles of specific microRNAs in regulating immune function of CB cells, providing insight into the underlying molecular mechanism.