He Yun, Xu Lin-Lin, Feng Fei-Er, Wang Qian-Ming, Zhu Xiao-Lu, Wang Chen-Cong, Zhang Jia-Min, Fu Hai-Xia, Xu Lan-Ping, Liu Kai-Yan, Huang Xiao-Jun, Zhang Xiao-Hui
Peking University People's Hospital, Peking University Institute of Haematology, Beijing, China.
Beijing Key Laboratory of Haematopoietic Stem Cell Transplantation, Beijing, China.
Br J Haematol. 2018 Feb;180(3):395-411. doi: 10.1111/bjh.15034. Epub 2018 Jan 12.
Immune thrombocytopenia (ITP) is an autoimmune disease. Mesenchymal stem cells (MSCs) play important roles in the physiology and homeostasis of the haematopoietic system, including supporting megakaryocytic differentiation from CD34 haematopoietic progenitor cells. Tumour necrosis factor alpha-induced protein 3 (TNFAIP3, also termed A20) plays a key role in terminating NF-κB signalling. Human genetic studies showed that the polymorphisms of the TNFAIP3 gene may contribute to ITP susceptibility. In this study, we showed a significant decrease in TNFAIP3 and increase in NF-κB/SMAD7 in ITP-MSCs. In co-cultures with CD34 cells, NF-κB was overexpressed in MSCs from healthy controls (HC-MSCs) after transfection with NFKBIA (IκB)-specific short hairpin (sh)RNAs, resulting in MSC deficiency and a reduction in megakaryocytic differentiation and thrombopoiesis. Knockdown of TNFAIP3 expression using TNFAIP3-specific shRNAs in HC-MSCs affected megakaryocytopoiesis. However, IKBKB knockdown corrected megakaryocytopoiesis inhibition in the ITP-MSCs by decreasing NF-κB expression. Amplified TNFAIP3 expression in ITP-MSCs by TNFAIP3 cDNA can facilitate megakaryocyte differentiation. shRNA-mediated knockdown of SMAD7 expression rescued the impaired MSC function in ITP patients. Therefore, we demonstrate that a pathological reduction in TNFAIP3 levels induced NF-κB/SMAD7 pathway activation, causing a deficiency in MSCs in ITP patients. The ability of ITP-MSCs to support megakaryocytic differentiation and thrombopoiesis of CD34 cells was impaired.
免疫性血小板减少症（ITP）是一种自身免疫性疾病。间充质干细胞（MSC）在造血系统的生理和稳态中发挥重要作用，包括支持CD34造血祖细胞向巨核细胞分化。肿瘤坏死因子α诱导蛋白3（TNFAIP3，也称为A20）在终止NF-κB信号传导中起关键作用。人类遗传学研究表明，TNFAIP3基因的多态性可能与ITP易感性有关。在本研究中，我们发现ITP-MSC中TNFAIP3显著降低，NF-κB/SMAD7升高。在与CD34细胞共培养时，用NFKBIA（IκB）特异性短发夹（sh）RNA转染后，健康对照（HC-MSC）的MSC中NF-κB过表达，导致MSC缺陷以及巨核细胞分化和血小板生成减少。在HC-MSC中使用TNFAIP3特异性shRNA敲低TNFAIP3表达会影响巨核细胞生成。然而，敲低IKBKB可通过降低NF-κB表达纠正ITP-MSC中的巨核细胞生成抑制。通过TNFAIP3 cDNA扩增ITP-MSC中的TNFAIP3表达可促进巨核细胞分化。shRNA介导的敲低SMAD7表达可挽救ITP患者受损的MSC功能。因此，我们证明TNFAIP3水平的病理性降低诱导NF-κB/SMAD7途径激活，导致ITP患者的MSC缺陷。ITP-MSC支持CD34细胞巨核细胞分化和血小板生成的能力受损。
