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BackgroundMicroRNAs (miRNAs) are small (19-22-nt) single-stranded noncoding RNA molecules whose deregulation of expression can contribute to human disease including the multistep processes of carcinogenesis in human. Circulating miRNAs are emerging biomarkers in many diseases and cancers such as type 2 diabetes, pulmonary disease, colorectal cancer, and gastric cancer among others; however, defining a plasma miRNA signature in acute myeloblastic leukemia (AML) that could serve as a biomarker for diagnosis or in the follow-up has not been done yet.MethodsTaqMan miRNA microarray was performed to identify deregulated miRNAs in the plasma of AML patients. Quantitative real-time RT-PCR was used to validate the results. Receiver-operator characteristic (ROC) curve analysis was conducted to evaluate the diagnostic accuracy of the highly and significantly identified deregulated miRNA(s) as potential candidate biomarker(s).ResultsThe plasma expression level of let-7d, miR-150, miR-339, and miR-342 was down-regulated whilst that of let-7b, and miR-523 was up-regulated in the AML group at diagnosis compared to healthy controls. ROC curve analyses revealed an AUC (the areas under the ROC curve) of 0.835 (95% CI: 0.7119– 0.9581; P<0.0001) and 0.8125 (95% CI: 0.6796–0.9454; P=0.0005) for miR-150, and miR-342 respectively. Combined ROC analyses using these 2 miRNAs revealed an elevated AUC of 0.86 (95% CI: 0.7819–0.94; P<0.0001) indicating the additive effect in the diagnostic value of these 2 miRNAs. QRT-PCR results showed that the expression level of these two miRs in complete remission AML patients resembled that of healthy controls.ConclusionsOur findings indicated that plasma miR-150 and miR-342 are novel important promising biomarkers in the diagnosis of AML. These novel and promising markers warrant validation in larger prospective studies.

Preparations of mesenchymal stromal cells (MSCs) are generally obtained from unfractionated tissue cells, resulting in heterogeneous cell mixtures. Several markers were proposed to enrich these cells, but the majority of these markers are defined for bone marrow (BM). Moreover, the surface markers of freshly isolated MSCs also differ from those of cultured MSCs in addition to a phenotypic variation depending on the MSC source. For tissue engineering applications, it is crucial to start with a well-defined cell population. In this study, we performed immunomagnetic selections with five single surface markers to isolate MSC subpopulations from BM and adipose tissue (AT): CD271, SUSD2, MSCA-1, CD44, and CD34. We determined the phenotype, the clonogenicity, the proliferation, the differentiation capacity, and the immunoregulatory profile of the subpopulations obtained in comparison with unselected cells. We showed that native BM-MSCs can be enriched from the positive fractions of MSCA-1, SUSD2, and CD271 selections. In contrast, we observed that SUSD2 and MSCA-1 were unable to identify MSCs from AT, meaning they are not expressed in situ. Only the CD34(+) selection successfully isolated MSCs from AT. Interestingly, we observed that CD271 selection can define AT cell subsets with particular abilities, but only in lipoaspiration samples and not in abdominoplasty samples. Importantly, we found a population of clear CD34(+) fresh BM-MSCs displaying different properties. A single marker-based selection for MSC enrichment should be more advantageous for cell therapy and would enable the standardization of efficient and safe therapeutic intervention through the use of a well-identified and homogeneous cell population.

Based on their ability to regulate immune responses, MSCs are considered to be potential candidates for managing immune-mediated diseases in the context of immune therapy. AT and WJ are considered valuable alternatives for BM as a source of MSCs. A detailed and comparative characterization of the immunological profile of MSCs derived from different sources, as well as an understanding of their responsiveness under certain circumstances, such as inflammation, is required to facilitate efficient and well-designed clinical studies. Flow cytometric analyses revealed clear differences among MSC types concerning the expression of the endothelial (e.g., CD31, CD34, CD144 and CD309) and stromal (e.g., CD90 and CD105) associated markers. Regardless of their source, MSCs did not express any of the known hematopoietic markers. All MSCs were uniformly positive for HLA-ABC and lacked the expression of HLA-DR and the co-stimulatory molecules (e.g., CD40, CD80, CD86, CD134 and CD252) required for full T-cell activation. Tissue-specific MSCs presented a modulated expression of cell adhesion molecules that is important for their cellular interactions. MSCs exhibited several surface (e.g., CD73, HLA-G, HO-1 and CD274) and soluble (e.g., HGF, PGE2 and IGFBP-3) immunoregulatory molecules. According to these immunological profiles, the present work provides evidence that the source from which MSCs are derived is important for the design of MSC-based immunointervention approaches. In light of these observations, we may suggest that WJ-MSCs appear to be the most attractive cell population to use in immune cellular therapy when immunosuppressive action is required.