hsa-miR-503 is downregulated in β thalassemia major.

TLDR: Whether there is a variance in the expression level of hsa-miR-503 in red blood cells of thalassemic and hematologically normal individuals is investigated to study how the miRNA expression profile is modulated in patients withThalassemia major.

Abstract: 5(G 1 C). All probands were aged between 20 and 30 years. Written informed consent was obtained from them, and the institutional human research committee approved the study. The ethical principles followed by the institute are guided by rules as formulated by the Indian Council of Medical Research and these are in agreement with the Helsinki rules. The CD34+ hematopoietic stem cells were first isolated from peripheral blood samples of these probands via the MACS cell separation technique and they were then grown following a two-step culture system to achieve the unilineage differentiation into mature erythrocytes [6] . Ninety percent of the cells became benzidine positive by day 13 in normal samples. The cells were harvested on the 13th day of culture by selecting for CD235a expression using an immunomagnetic isolation procedure and processed for miRNA and mRNA isolation ( mir VanaTM miRNA Isolation Kit; Ambion). Solution hybridization was performed with an mir Vana miRNA Probe Construction Kit (Ambion) and an mir Vana miRNA Detection Kit (Ambion) following the manufacturer’s instructions. For probe labeling, 32 P CTP (BRIT, India) was used. The intensity of the bands was analyzed using Imagequant software. U6 MicroRNAs (miRNAs) are small, 22to 25-nt-long, endogenous, non-proteincoding RNA molecules which have the potential to downregulate gene expression. The involvement of miRNAs in several biological processes has been demonstrated, and diseased states are characterized by altered expression of miRNAs [1] . We intended to study how the miRNA expression profile is modulated in patients with thalassemia major. Thalassemia is characterized by an enhanced rate of growth of erythropoietic progenitors leading to marrow expansion and resultant iron absorption [2] . Of the various miRNAs expressed during erythropoiesis, hsa-miR-503 has been implicated in regulation of genes involved in cell cycle arrest and apoptosis [3–5] . To investigate whether there is a variance in the expression level of hsa-miR-503 in red blood cells of thalassemic and hematologically normal individuals, four patients with  thalassemia major, four with Ethalassemia major, and two with Ethalassemia intermedia, as well as four normal healthy adult volunteers, were recruited. All  major patients studied here are homozygous for the mutation IVS-I nt 5(G 1 C). The intermedia and severe patients of HbE/ thalassemia are compound heterozygous for HbE and IVS-I nt Received: March 5, 2012 Accepted after revision: May 8, 2012 Published online: August 11, 2012