Expression data of genes that regulate reactive oxygen species in bone marrow mononuclear cells from patients with Shwachman-Diamond syndrome

Although anemia is common in Shwachman-Diamond syndrome (SDS), the underlying mechanism remains unclear. We asked whether SBDS, which is mutated in most SDS patients, is critical for erythroid development. We found that SBDS expression is high early during erythroid differentiation. Inhibition of SBDS in CD34+ hematopoietic stem cells and early progenitors (HSC/Ps) and K562 cells led to slow cell expansion during erythroid differentiation. Induction of erythroid differentiation resulted in markedly accelerated apoptosis in the knockdown cells; however, proliferation was only mildly reduced. The percentage of cells entering differentiation was not reduced. Differentiation also increased the oxidative stress in SBDS-knockdown K562 cells, and antioxidants enhanced the expansion capability of differentiating SBDS-knockdown K562 cells and colony production of SDS patient HSC/Ps. Erythroid differentiation also resulted in reduction of all ribosomal subunits and global translation. Furthermore, stimulation of global translation with leucine improved the erythroid cell expansion of SBDS-knockdown cells and colony production of SDS patient HSC/Ps. Leucine did not reduce the oxidative stress in SBDS-deficient K562 cells. These results demonstrate that SBDS is critical for normal erythropoiesis. Erythropoietic failure caused by SBDS-deficiency is at least in part related to elevated ROS levels and translation insufficiency since antioxidants and leucine improved cell expansion. Bone marrow mononuclear cells from nine SDS patients and nine control patients were selected for RNA extraction and hybridization on Affymetrix microarrays.

虽然贫血在施瓦赫曼-戴蒙德综合征（Shwachman-Diamond syndrome, SDS）中较为常见，但其潜在发病机制仍未阐明。我们针对大多数SDS患者中发生突变的SBDS基因，探究其对红细胞发育是否具有关键作用。研究发现，SBDS在红细胞分化早期的表达水平较高。在CD34+造血干细胞及早期祖细胞（hematopoietic stem cells and early progenitors, HSC/Ps）与K562细胞中抑制SBDS表达后，红细胞分化过程中的细胞增殖速率显著减慢。诱导红细胞分化后，SBDS敲低细胞的凋亡进程明显加速，但增殖仅出现轻度降低，且进入分化阶段的细胞比例未受影响。分化过程还会使SBDS敲低的K562细胞内氧化应激水平升高，而抗氧化剂可增强分化中SBDS敲低K562细胞的增殖能力，同时改善SDS患者HSC/Ps的集落形成能力。红细胞分化同时可导致所有核糖体亚基及全局翻译水平下降。此外，通过亮氨酸促进全局翻译，可改善SBDS敲低细胞的红细胞增殖能力，以及SDS患者HSC/Ps的集落形成能力；但亮氨酸无法降低SBDS缺陷型K562细胞内的氧化应激水平。上述结果证实，SBDS对正常红细胞生成至关重要。由SBDS缺陷引发的红细胞生成障碍，至少部分与活性氧（reactive oxygen species, ROS）水平升高及翻译功能不足相关，因抗氧化剂与亮氨酸均可改善细胞增殖情况。本研究选取9名SDS患者与9名对照患者的骨髓单个核细胞，进行RNA提取并在Affymetrix基因芯片上完成杂交。