Nemeth Michael J, Topol Lilia, Anderson Stacie M, Yang Yingzi, Bodine David M
Genetics and Molecular Biology Branch, National Human Genome Research Institute, Bethesda, MD 20892-4442, USA.
Proc Natl Acad Sci U S A. 2007 Sep 25;104(39):15436-41. doi: 10.1073/pnas.0704747104. Epub 2007 Sep 19.
The mechanisms that regulate hematopoietic stem cell (HSC) fate decisions between proliferation and multilineage differentiation are unclear. Members of the Wnt family of ligands that activate the canonical Wnt signaling pathway, which utilizes beta-catenin to relay the signal, have been demonstrated to regulate HSC function. In this study, we examined the role of noncanonical Wnt signaling in regulating HSC fate. We observed that noncanonical Wnt5a inhibited Wnt3a-mediated canonical Wnt signaling in HSCs and suppressed Wnt3a-mediated alterations in gene expression associated with HSC differentiation, such as increased expression of myc. Wnt5a increased short- and long-term HSC repopulation by maintaining HSCs in a quiescent G(0) state. From these data, we propose that Wnt5a regulates hematopoiesis by the antagonism of the canonical Wnt pathway, resulting in a pool of quiescent HSCs.
调节造血干细胞(HSC)在增殖和多谱系分化之间命运抉择的机制尚不清楚。激活经典Wnt信号通路(该通路利用β-连环蛋白传递信号)的Wnt配体家族成员已被证明可调节HSC功能。在本研究中,我们研究了非经典Wnt信号在调节HSC命运中的作用。我们观察到,非经典Wnt5a抑制HSC中Wnt3a介导的经典Wnt信号,并抑制Wnt3a介导的与HSC分化相关的基因表达变化,如myc表达增加。Wnt5a通过将HSC维持在静止的G(0)状态来增加短期和长期HSC的重新增殖能力。基于这些数据,我们提出Wnt5a通过拮抗经典Wnt通路来调节造血作用,从而产生一群静止的HSC。