Borghesi Lisa
Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
J Immunol. 2014 Sep 1;193(5):2053-8. doi: 10.4049/jimmunol.1400936.
Long-term hematopoietic stem cells (LT-HSCs) replenish the innate and adaptive immune compartments throughout life. Although significant progress has defined the major transcription factors that regulate lineage specification, the architectural proteins that globally coordinate DNA methylation, histone modification, and changes in gene expression are poorly defined. Provocative new studies establish the chromatin organizer special AT-rich binding protein 1 (Satb1) as one such global regulator in LT-HSCs. Satb1 is a nuclear organizer that partitions chromatin through the formation of cage-like structures. By integrating epigenetic and transcriptional pathways, Satb1 coordinates LT-HSC division, self-renewal, and lymphoid potential. Unexpected among the assortment of genes under Satb1 control in hematopoietic stem cells (HSCs) are cytokines, a finding that takes on additional importance with the provocative finding that short-term HSCs and downstream multipotent progenitors are potent and biologically relevant cytokine secretors during stress-mediated hematopoiesis. Together, these studies reveal a new mechanism of fate regulation and an unforeseen functional capability of HSCs.
长期造血干细胞(LT-HSCs)在整个生命过程中补充固有免疫和适应性免疫细胞库。尽管在确定调节谱系特异性的主要转录因子方面取得了重大进展,但对全局协调DNA甲基化、组蛋白修饰和基因表达变化的结构蛋白仍知之甚少。引人注目的新研究表明,染色质组织者特殊富含AT序列结合蛋白1(Satb1)是LT-HSCs中的一种此类全局调节因子。Satb1是一种核组织者,通过形成笼状结构来分隔染色质。通过整合表观遗传和转录途径,Satb1协调LT-HSC的分裂、自我更新和淋巴样潜能。在造血干细胞(HSCs)中受Satb1控制的各种基因中,细胞因子出人意料,这一发现因另一个引人注目的发现而变得更加重要,即短期HSCs和下游多能祖细胞在应激介导的造血过程中是强大且具有生物学相关性的细胞因子分泌者。这些研究共同揭示了一种新的命运调节机制以及HSCs一种意想不到的功能能力。