Mackay-Sim A
National Centre for Adult Stem Cell Research, Eskitis Institute for Cell and Molecular Therapies, Griffith University, Brisbane, Australia.
Arch Ital Biol. 2010 Jun;148(2):47-58.
It is well known that new neurons are produced in the adult brain, in the hippocampus and in the subventricular zone. The neural progenitors formed in the subventricular zone migrate forward and join in neural circuits as interneurons in the olfactory bulb, the target for axons from the olfactory sensory neurons in the nose. These neurons are also continually replaced during adulthood from a stem cell in a neurogenic niche in the olfactory epithelium. The stem cell responsible can regenerate all the cells of the olfactory epithelium if damaged by trauma or toxins. This stem cell, the horizontal basal cell, is in a niche defined by the extra cellular matrix of the basement membrane as well as the many growth factors expressed by surrounding cells and hormones from nearby vasculature. A multipotent cell has been isolated from the olfactory mucosa that can give rise to cells of endodermal and mesodermal origin as well as the expected neural lineage. Whether this is an additional stem cell or the horizontal basal cell is still an open question.
众所周知，成人大脑中会产生新的神经元，这些神经元产生于海马体和脑室下区。脑室下区形成的神经祖细胞向前迁移，并作为中间神经元加入神经回路，进入嗅球，而嗅球是鼻子中嗅觉感觉神经元轴突的靶标。在成年期，这些神经元也会不断地从嗅觉上皮神经发生微环境中的干细胞得到补充。如果受到创伤或毒素损害，负责的干细胞可以再生嗅觉上皮的所有细胞。这种干细胞，即水平基底细胞，存在于由基底膜的细胞外基质以及周围细胞表达的多种生长因子和附近脉管系统的激素所界定的微环境中。已经从嗅觉黏膜中分离出一种多能细胞，它可以产生内胚层和中胚层来源的细胞以及预期的神经谱系细胞。这是一种额外的干细胞还是水平基底细胞，仍然是一个悬而未决的问题。
