Zhou Qiong, Obana Edwin A, Radomski Kryslaine L, Sukumar Gauthaman, Wynder Christopher, Dalgard Clifton L, Doughty Martin L
Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814 Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814.
Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814.
Mol Biol Cell. 2016 Feb 15;27(4):627-39. doi: 10.1091/mbc.E15-07-0513. Epub 2016 Jan 6.
The role of epigenetic regulators in the control of adult neurogenesis is largely undefined. We show that the histone demethylase enzyme Kdm5b (Jarid1b) negatively regulates neurogenesis from adult subventricular zone (SVZ) neural stem cells (NSCs) in culture. shRNA-mediated depletion of Kdm5b in proliferating adult NSCs decreased proliferation rates and reduced neurosphere formation in culture. When transferred to differentiation culture conditions, Kdm5b-depleted adult NSCs migrated from neurospheres with increased velocity. Whole-genome expression screening revealed widespread transcriptional changes with Kdm5b depletion, notably the up-regulation of reelin (Reln), the inhibition of steroid biosynthetic pathway component genes and the activation of genes with intracellular transport functions in cultured adult NSCs. Kdm5b depletion increased extracellular reelin concentration in the culture medium and increased phosphorylation of the downstream reelin signaling target Disabled-1 (Dab1). Sequestration of extracellular reelin with CR-50 reelin-blocking antibodies suppressed the increase in migratory velocity of Kdm5b-depleted adult NSCs. Chromatin immunoprecipitation revealed that Kdm5b is present at the proximal promoter of Reln, and H3K4me3 methylation was increased at this locus with Kdm5b depletion in differentiating adult NSCs. Combined the data suggest Kdm5b negatively regulates neurogenesis and represses Reln in neural stem cells from the adult SVZ.
表观遗传调节因子在成体神经发生控制中的作用在很大程度上尚不清楚。我们发现组蛋白去甲基化酶Kdm5b（Jarid1b）对培养的成体脑室下区（SVZ）神经干细胞（NSCs）的神经发生具有负向调节作用。shRNA介导的增殖期成体NSCs中Kdm5b的缺失降低了增殖速率并减少了培养中的神经球形成。当转移到分化培养条件下时，Kdm5b缺失的成体NSCs从神经球迁移的速度加快。全基因组表达筛选显示，Kdm5b缺失导致广泛的转录变化，特别是在培养的成体NSCs中，reelin（Reln）上调、类固醇生物合成途径成分基因受到抑制以及具有细胞内运输功能的基因被激活。Kdm5b缺失增加了培养基中细胞外reelin的浓度，并增加了下游reelin信号靶点Disabled-1（Dab1）的磷酸化。用CR-50 reelin阻断抗体隔离细胞外reelin可抑制Kdm5b缺失的成体NSCs迁移速度的增加。染色质免疫沉淀显示，Kdm5b存在于Reln的近端启动子处，在分化的成体NSCs中，随着Kdm5b的缺失，该位点的H3K4me3甲基化增加。综合这些数据表明，Kdm5b对成体SVZ神经干细胞的神经发生具有负向调节作用，并抑制Reln。
