PDF(Pubmed)
Abstract：
Self-renewal and differentiation of hematopoietic stem and progenitor cells (HSPCs) are carefully controlled by extrinsic and intrinsic factors, to ensure the lifelong process of hematopoiesis. Apurinic/apyrimidinic endonuclease 1 (APEX1) is a multifunctional protein implicated in DNA repair and transcriptional regulation. Although previous studies have emphasized the necessity of studying APEX1 in a lineage-specific context and its role in progenitor differentiation, no studies have assessed the role of APEX1, nor its two enzymatic domains, in supporting adult HSPC function. In this study, we demonstrated that complete loss of APEX1 from murine bone marrow HSPCs (induced by CRISPR/Cas9) caused severe hematopoietic failure following transplantation, as well as a HSPC expansion defect in culture conditions maintaining in vivo HSC functionality. Using specific inhibitors against either the nuclease or redox domains of APEX1 in combination with single cell transcriptomics (CITE-seq), we found that both APEX1 nuclease and redox domains are regulating mouse HSPCs, but through distinct underlying transcriptional changes. Inhibition of the APEX1 nuclease function resulted in loss of HSPCs accompanied by early activation of differentiation programs and enhanced lineage commitment. By contrast, inhibition of the APEX1 redox function significantly downregulated interferon-stimulated genes and regulons in expanding HSPCs and their progeny, resulting in dysfunctional megakaryocyte-biased HSPCs, as well as loss of monocytes and lymphoid progenitor cells. In conclusion, we demonstrate that APEX1 is a key regulator for adult regenerative hematopoiesis, and that the APEX1 nuclease and redox domains differently impact proliferating HSPCs.
摘要：
造血干细胞和祖细胞（HSPC）的自我更新和分化受到外在和内在因素的控制。确保造血的终身过程。脱嘌呤/无嘧啶核酸内切酶1（APEX1）是一种参与DNA修复和转录调控的多功能蛋白质。尽管以前的研究强调了在谱系特异性背景下研究APEX1的必要性及其在祖细胞分化中的作用，没有研究评估APEX1的作用，也没有它的两个酶域，支持成人HSPC功能。在这项研究中,我们证明了小鼠骨髓HSPCs（CRISPR/Cas9诱导）中APEX1的完全丢失导致移植后严重的造血功能衰竭，以及在维持体内HSC功能的培养条件下的HSPC扩增缺陷。使用针对APEX1的核酸酶或氧化还原结构域的特异性抑制剂与单细胞转录组学（CITE-seq）组合，我们发现APEX1核酸酶和氧化还原结构域都在调节小鼠HSPCs，而是通过明显的潜在转录变化。APEX1核酸酶功能的抑制导致HSPC的丧失,伴随着分化程序的早期激活和谱系定型的增强。相比之下,APEX1氧化还原功能的抑制显着下调扩大HSPCs及其后代中干扰素刺激的基因和调节子，导致功能失调的巨核细胞偏向的HSPCs，以及单核细胞和淋巴祖细胞的损失。总之,我们证明APEX1是成人再生造血的关键调节因子，APEX1核酸酶和氧化还原结构域对HSPC增殖的影响不同。
