PDF(Pubmed)
Abstract：
Chondroitin sulfate proteoglycans (CSPGs) are fundamental components of the extracellular matrix in the central nervous system (CNS). Among these, the Nerve-Glial antigen 2 (NG2) stands out as a transmembrane CSPG exclusively expressed in a different population of cells collectively termed NG2-expressing cells. These enigmatic cells, found throughout the developing and adult CNS, have been indicated with various names, including NG2 progenitor cells, polydendrocytes, synantocytes, NG2 cells, and NG2-Glia, but are more commonly referred to as oligodendrocyte progenitor cells. Characterized by high proliferation rates and unique morphology, NG2-expressing cells stand apart from neurons, astrocytes, and oligodendrocytes. Intriguingly, some NG2-expressing cells form functional glutamatergic synapses with neurons, challenging the long-held belief that only neurons possess the intricate machinery required for neurotransmission. In the CNS, the complexity surrounding NG2-expressing cells extends to their classification. Additionally, NG2 expression has been documented in pericytes and immune cells, suggesting a role in regulating brain innate immunity and neuro-immune crosstalk in homeostasis. Ongoing debates revolve around their heterogeneity, potential as progenitors for various cell types, responses to neuroinflammation, and the role of NG2. Therefore, this review aims to shed light on the enigma of NG2-expressing cells by delving into their structure, functions, and signaling pathways. We will critically evaluate the literature on NG2 expression across the CNS, and address the contentious issues surrounding their classification and roles in neuroinflammation and neurodegeneration. By unraveling the intricacies of NG2-expressing cells, we hope to pave the way for a more comprehensive understanding of their contributions to CNS health and during neurological disorders.
摘要：
硫酸软骨素蛋白聚糖(CSPGs)是中枢神经系统(CNS)细胞外基质的基本成分。其中,神经胶质抗原2（NG2）作为跨膜CSPG，在不同的细胞群体中专门表达，统称为NG2表达细胞。这些神秘的细胞，在发育中和成年的中枢神经系统中发现，已经用各种名称表示，包括NG2祖细胞，多突胶质细胞,突触细胞，NG2细胞,NG2-Glia,但通常被称为少突胶质细胞祖细胞。以高增殖率和独特的形态为特征，NG2表达细胞与神经元分离，星形胶质细胞,和少突胶质细胞。有趣的是，一些NG2表达细胞与神经元形成功能性谷氨酸能突触，挑战长期以来的信念，即只有神经元拥有神经传递所需的复杂机制。在中枢神经系统，围绕NG2表达细胞的复杂性延伸到它们的分类。此外,NG2表达已在周细胞和免疫细胞中被证明，提示在调节大脑先天免疫和神经免疫串扰中的作用。正在进行的辩论围绕着它们的异质性，作为各种细胞类型的祖细胞的潜力，对神经炎症的反应，以及NG2的作用。因此,这篇综述旨在通过深入研究NG2表达细胞的结构来揭示它们的谜团，功能,和信号通路。我们将批判性地评估NG2在中枢神经系统表达的文献，并解决围绕它们在神经炎症和神经变性中的分类和作用的有争议的问题。通过解开NG2表达细胞的复杂性，我们希望为更全面地了解它们对中枢神经系统健康和神经系统疾病的贡献铺平道路.
