U251细胞生物学特性

Human Astrocytes

Astrocytes make up the majority of the cells in the mammalian brain. They are the most variable in type, most intimately associated with all parts of neurons, and thus most functionally interesting in their relationships with neurons [1]. They provide structural, trophic, and metabolic support to neurons and modulate synaptic activity. Impairment of these astrocyte functions during stroke and other insults can critically influence neuron survival. Furthermore, astrocytes have been implicated in the pathological processes of many neurological diseases [2]. Long-term recovery after brain injury, through neurite outgrowth, synaptic plasticity, or neuron regeneration, is influenced by astrocyte surface molecule expression and trophic factor release [3]. In addition, the death or survival of astrocytes themselves may affect the ultimate clinical outcome. Recognition of the importance of astrocytes in nervous system functioning is increasing, specifically regarding the modulation of neural activity. Much of what wehave learned about astrocytes is from the in vitro studies and astrocyte cultures are continuing to provide a useful tool in exploring the diverse property of these cells.

Reference

[1] G. I. Hatton (2002) Glial-neuronal interactions in the mammalian brain. Adv. in Physiol. Edu. 26:225-237.

[2] Van der Laan, L. J. W., De Groot, C. J. A., Elices, M. J. and Dijkstran, C. D. (1997) Extracellular matrix proteins expressed by human adult astrocytes in vivo and in vitro: an astrocyte surface protein containing the CS1 domain contributes to binding of lymphoblasts. J. Neurosci. Res. 50:539-548.

[3] Chen Y., and Swanson, R. A. (2003) Astrocytes and brain injury. J. Cereb. Blood Flow Metab. 23:137-149.

Human Microglia

Microglia, one of the glial cell types in the CNS, are an important integral component of neuro-glial cell network [1]. They have been observed in the brain parenchyma from the early stage of development to the mature state. Microglia act as brain macrophages when programmed cell death occurs during brain development or when the CNS is injured or pathologically damaged. Microglia can be considered as the main cell in brain immune surveillance, can present antigens in the molecular context of MHC class II expression to CD-4 positive T cells, are capable of Fc-mediated phagocytosis, and share many common antigens with hemopoietic and tissue macrophages [2]. Furthermore, there is accumulating evidence that microglia are involved in a variety of physiological and pathological processes in the brain by interacting with neurons and other glial cells and through production of biologically active substances such as growth factors, cytokines, and other factors [3].

Reference

[1] Lee, S. C., Liu, W., Brosnan, C. F. and Dickson, D. W. (1992) Characterization of primary human fetal dissociated central nervous system cultures with an emphasis on microgia. Laboratory Investigation. 67:465-476.

[2] Fedoroff, S., Zhai, R. and Novak, J. P. (1997) Microglia and astroglia have a common progenitor cell. J. Neurosci. Res. 50: 477-486.

[3] Stoll, G. and Jander, S. (1999) The role of microglia and macrophages in the pathophysiology of the CNS. Prog. Neurobiol. 58:233-247.