DEPENDENCE OF SALIVARY EPITHELIAL MORPHOLOGY AND BRANCHING MORPHOGENESIS UPON ACID MUCOPOLYSACCHARIDE-PROTEIN (PROTEOGLYCAN) AT THE EPITHELIAL SURFACE
DEPENDENCE OF SALIVARY EPITHELIAL MORPHOLOGY AND BRANCHING MORPHOGENESIS UPON ACID MUCOPOLYSACCHARIDE-PROTEIN (PROTEOGLYCAN) AT THE EPITHELIAL SURFACE
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唾液上皮形态和分支形态发生对上皮表面酸性粘多糖蛋白（蛋白聚糖）的依赖性
作者：
M. Bernfield;S. Banerjee;R. Cohn
通过比较去除酸性粘多糖的上皮组织和保留酸性粘多糖的上皮组织在体外的形态发生，研究了酸性粘多糖（糖胺聚糖）在小鼠胚胎下颌下腺上皮表面的形态发生作用。通过保留大部分表面粘多糖的方法分离出的不含间充质的上皮组织，在与新鲜间充质直接组合培养时，能保持其小叶形状，并进行不间断的分支形态发生。在相同的培养条件下，去除表面粘多糖的上皮组织会失去小叶，变成球形组织块。在持续培养过程中，球形上皮组织会产生突起，分支形态发生从这些突起处重新开始。具有形态发生活性的粘多糖位于上皮基底膜的基底层内，似乎与蛋白质结合。在与间充质共同培养过程中，进行不间断形态发生的上皮组织在小叶远端（即初始分支部位）新合成的表面粘多糖积累最多。相比之下，这种物质在球形上皮组织表面的积累几乎是均匀的，但在芽状突起表面（即形态发生将重新开始的部位）积累更多。快速增殖的细胞位于进行不间断形态发生的上皮组织的小叶内，但在球形上皮组织的皮质中均匀分布，除了突起处增殖细胞更多。结论是，正常的唾液腺上皮形态和分支形态发生需要上皮基底层内存在酸性粘多糖 - 蛋白质。
The morphogenetic role of the acid mucopolysaccharide (glycosaminoglycan) at the epithelial surface of mouse embryo submandibular glands has been studied by comparing the in vitro morphogenesis of epithelia from which the mucopolysaccharide was removed with that of those that retained the mucopolysaccharide. Epithelia isolated free of mesenchyme by procedures which retain the bulk of surface mucopolysaccharide maintain their lobular shape and undergo uninterrupted branching morphogenesis in culture in direct combination with fresh mesenchyme. Under identical culture conditions, epithelia from which surface mucopolysaccharide was removed lose their lobules and become spherical masses of tissue. During continued culture, the spherical epithelia produce outgrowths from which branching morphogenesis resumes. The morphogenetically active mucopolysaccharide is localized within the basal lamina of the epithelial basement membrane and appears to be bound to protein. During culture in combination with mesenchyme, epithelia undergoing uninterrupted morphogenesis show maximal accumulation of newly synthesized surface mucopolysaccharide at the distal ends of the lobules, the sites of incipient branching. In contrast, the material accumulates nearly equivalently over the surface of the spherical epithelia, with the exception that there is greater accumulation of the material at the surfaces of the budding outgrowths, the sites where morphogenesis will resume. Rapidly proliferating cells are localized within the lobules of epithelia undergoing uninterrupted morphogenesis, but are distributed uniformly in the cortex of the spherical epithelia, except for the outgrowths which show a greater localization of proliferating cells. It is concluded that normal salivary epithelial morphology and branching morphegenesis require the presence of acid mucopolysaccharide-protein within the epithelial basal lamina.