神经节苷脂是唾液酸化的鞘糖脂,在健康和疾病大脑中具有基本但神秘的功能。GD3是神经干细胞(NSC)中的主要物种,GD3-合酶(唾液酸转移酶II;St8Sia1)敲除(GD3S-KO)显示产后NSC池减少,包括认知障碍在内的严重行为缺陷,抑郁样表型,和嗅觉功能障碍。GD3的外源性施用显着恢复了NSC池,并增强了具有多能性和自我更新的NSC的干性,其次是恢复的神经元功能。我们小组发现GD3通过与表皮生长因子受体(EGFRs)相互作用参与NSC命运决定的维持,通过调节细胞周期蛋白依赖性激酶(CDK)抑制剂p27和p21的表达,并通过结合线粒体裂变蛋白调节线粒体动力学,动力蛋白相关蛋白-1(Drp1)。此外,我们发现核GM1通过表观遗传调节机制促进神经元分化。GM1与N-乙酰半乳糖胺转移酶(GalNAcT;GM2合酶(GM2S);B4galnt1)启动子上的乙酰化组蛋白以及分化神经元中的NeuroD1结合。此外,检测到GM2S基因的表观遗传激活,伴随着对外源性GM1补充的NSC中神经元分化的明显诱导。有趣的是,GM1诱导酪氨酸羟化酶(TH)基因的表观遗传激活,随着Nurr1和PITX3的募集,多巴胺能神经元相关转录因子,到TH启动子区。这样,GM1表观遗传学调节多巴胺能神经元特异性基因表达,它会改变帕金森病。多功能神经节苷脂显着调节脂质微域,以调节多个位点上重要分子的功能:质膜,线粒体膜,和核膜。多功能神经节苷脂通过调节神经节苷脂微结构域上的蛋白质和基因活性来调节功能性神经元并维持NSC功能。维持适当的神经节苷脂微结构域有益于健康的神经元发育和数百万患有神经退行性疾病的老年人。这里,我们介绍了如何分离GD3和GM1,以及如何将它们施用到小鼠大脑中,以研究它们对NSC命运决定和神经细胞规范的功能。
Gangliosides are sialylated glycosphingolipids with essential but enigmatic functions in healthy and disease brains.
GD3 is the predominant species in neural stem cells (NSCs) and
GD3-synthase (sialyltransferase II; St8Sia1) knockout (GD3S-KO) revealed reduction of postnatal NSC pools with severe behavioral deficits including cognitive impairment, depression-like phenotypes, and olfactory dysfunction. Exogenous administration of
GD3 significantly restored the NSC pools and enhanced the stemness of NSCs with multipotency and self-renewal, followed by restored neuronal functions. Our group discovered that
GD3 is involved in the maintenance of NSC fate determination by interacting with epidermal growth factor receptors (EGFRs), by modulating expression of cyclin-dependent kinase (CDK) inhibitors p27 and p21, and by regulating mitochondrial dynamics via associating a mitochondrial fission protein, the dynamin-related protein-1 (Drp1). Furthermore, we discovered that nuclear GM1 promotes neuronal differentiation by an epigenetic regulatory mechanism. GM1 binds with acetylated histones on the promoter of N-acetylgalactosaminyltransferase (GalNAcT; GM2 synthase (GM2S); B4galnt1) as well as on the NeuroD1 in differentiated neurons. In addition, epigenetic activation of the GM2S gene was detected as accompanied by an apparent induction of neuronal differentiation in NSCs responding to an exogenous supplement of GM1. Interestingly, GM1 induced epigenetic activation of the tyrosine hydroxylase (TH) gene, with recruitment of Nurr1 and PITX3, dopaminergic neuron-associated transcription factors, to the TH promoter region. In this way, GM1 epigenetically regulates dopaminergic neuron specific gene expression, and it would modify Parkinson\'s disease. Multifunctional gangliosides significantly modulate lipid microdomains to regulate functions of important molecules on multiple sites: the plasma membrane, mitochondrial membrane, and nuclear membrane. Versatile gangliosides regulate functional neurons as well as sustain NSC functions via modulating protein and gene activities on ganglioside microdomains. Maintaining proper ganglioside microdomains benefits healthy neuronal development and millions of senior citizens with neurodegenerative diseases. Here, we introduce how to isolate
GD3 and GM1 and how to administer them into the mouse brain to investigate their functions on NSC fate determination and nerve cell specification.