Faculty of Medical Technology, Prince of Songkla University, 15, Kanjanavanit Rd. Hat Yai, Songkhla, 90110, Thailand.
Section for Translational Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 25/25, 270 Rama VI Rd., Ratchathewi, Bangkok, 10400, Thailand.
Ann Hematol. 2019 Sep;98(9):2045-2052. doi: 10.1007/s00277-019-03737-4. Epub 2019 Jun 26.
Thalassemia has a high prevalence in Thailand. Oxidative damage to erythroid cells is known to be one of the major etiologies in thalassemia pathophysiology. Oxidative stress status of thalassemia is potentiated by the heme, nonheme iron, and free iron resulting from imbalanced globin synthesis. In addition, levels of antioxidant proteins are reduced in α-thalassemia and β-thalassemia erythrocytes. However, the primary molecular mechanism for this phenotype remains unknown. Our study showed a high expression of miR-144 in β- and α-thalassemia. An increased miR-144 expression leads to decreased expression of nuclear factor erythroid 2-related factor 2 (NRF2) target, especially in α-thalassemia. In α-thalassemia, miR-144 and NRF2 target are associated with glutathione level and anemia severity. To study the effect of miR-144 expression, the gain-loss of miR-144 expression was performed by miR inhibitor and mimic transfection in the erythroblastic cell line. This study reveals that miR-144 expression was upregulated, whereas NRF2 expression and glutathione levels were decreased in comparison with the untreated condition after miR mimic transfection, while the reduction of miR-144 expression contributed to the increased NRF2 expression and glutathione level compared with the untreated condition after miR inhibitor transfection. Moreover, miR-144 overexpression leads to significantly increased sensitivity to oxidative stress at indicated concentrations of hydrogen peroxide (HO) and rescued by miR-144 inhibitor. Taken together, our findings suggest that dysregulation of miR-144 may play a role in the reduced ability of erythrocyte to deal with oxidative stress and increased RBC hemolysis susceptibility especially in thalassemia.
地中海贫血在泰国的发病率很高。已知红细胞的氧化损伤是地中海贫血病理生理学的主要病因之一。由于球蛋白合成失衡,导致血红素、非血红素铁和游离铁的产生,从而加剧了地中海贫血的氧化应激状态。此外,α-地中海贫血和β-地中海贫血的红细胞中抗氧化蛋白水平降低。然而,这种表型的主要分子机制仍不清楚。我们的研究表明,miR-144 在β-和α-地中海贫血中表达较高。miR-144 表达增加导致核因子红细胞 2 相关因子 2(NRF2)靶基因的表达减少,特别是在α-地中海贫血中。在α-地中海贫血中,miR-144 和 NRF2 靶基因与谷胱甘肽水平和贫血严重程度相关。为了研究 miR-144 表达的影响,通过 miR 抑制剂和 mimic 转染在红系细胞系中进行了 miR-144 表达的增益和缺失实验。与未处理条件相比,本研究显示 miR-144 表达上调,而 NRF2 表达和谷胱甘肽水平降低,miR 模拟物转染后,与未处理条件相比,miR-144 表达的降低导致 NRF2 表达和谷胱甘肽水平增加。此外,miR-144 过表达导致在指示浓度的过氧化氢(HO)下对氧化应激的敏感性显著增加,并且可以被 miR-144 抑制剂挽救。总之,我们的研究结果表明,miR-144 的失调可能在红细胞应对氧化应激的能力降低和 RBC 溶血易感性增加中起作用,特别是在地中海贫血中。