Division of Hematology, Department of Pediatrics, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Cell Therapy and Transplant Section, Division of Oncology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
DNA Cell Biol. 2020 May;39(5):756-765. doi: 10.1089/dna.2019.5123. Epub 2020 Apr 13.
Iron-sulfur (Fe-S) clusters are required for mitochondrial function. Fe-S cluster synthesis occurs in the mitochondria and iron uptake is required for mitochondrial biogenesis. However, Fe-S clusters inhibit the expression of the iron importer transferrin receptor 1 (TfR1), whereas lack of the Fe-S cluster stimulates TfR1 expression. Yet, it is unclear whether Fe-S cluster synthesis increases with mitochondria biogenesis and, in turn, whether this negatively modulates TfR1 expression. We manipulated peroxisome proliferator-activated receptor-gamma coactivator-1α expression to control mitochondrial biogenesis in a variety of cell types, including erythroid cells. We demonstrated that Fe-S cluster synthesis increases with mitochondria biogenesis but does not interfere with increasing TfR1 expression. In fact, TfR1 expression is stimulated through alternative means to meet iron requirement for mitochondria biogenesis. Furthermore, under enhanced mitochondria biogenesis, increased Fe-S cluster synthesis inhibits the function of iron-regulating protein (IRP)1 and hence stimulates the expression of 5'-aminolevulinate synthase 2 (ALAS2), a target of IRP1 and rate-limiting enzyme in erythroid heme biogenesis. Increased ALAS2 expression leads to enhanced heme production, hemoglobinization, and erythropoiesis. Therefore, our study also provides a mechanism to link mitochondrial biogenesis with erythropoiesis and has a potential therapeutic value in the treatment of blood disorders.
铁硫 (Fe-S) 簇对于线粒体功能至关重要。Fe-S 簇的合成发生在线粒体中,而铁的摄取对于线粒体的生物发生是必需的。然而,Fe-S 簇抑制铁摄取蛋白转铁蛋白受体 1 (TfR1) 的表达,而缺乏 Fe-S 簇则刺激 TfR1 的表达。然而,尚不清楚 Fe-S 簇的合成是否随着线粒体的生物发生而增加,以及这种情况是否会反过来负调节 TfR1 的表达。我们操纵过氧化物酶体增殖物激活受体-γ共激活因子 1α 的表达,以控制各种细胞类型(包括红细胞)中线粒体的生物发生。我们证明,Fe-S 簇的合成随着线粒体的生物发生而增加,但不会干扰 TfR1 表达的增加。事实上,TfR1 的表达通过替代途径被刺激,以满足线粒体生物发生所需的铁。此外,在增强的线粒体生物发生下,增加的 Fe-S 簇合成抑制铁调节蛋白 (IRP)1 的功能,从而刺激铁调节蛋白 1 的靶标 5'-氨基酮戊酸合酶 2 (ALAS2) 的表达,这是红细胞血红素生物发生的限速酶。增加的 ALAS2 表达导致血红素产生、血红蛋白化和红细胞生成增加。因此,我们的研究还提供了一种将线粒体生物发生与红细胞生成联系起来的机制,并在治疗血液疾病方面具有潜在的治疗价值。