Liu J Y, Nettesheim P, Randell S H
Laboratory of Pulmonary Pathobiology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709.
Am J Physiol. 1994 Mar;266(3 Pt 1):L296-307. doi: 10.1152/ajplung.1994.266.3.L296.
The purpose of these studies was to determine whether both basal and secretory rat tracheal epithelial (RTE) cells served as multipotent epithelial progenitors and whether both cell types gave rise to a similar "poorly differentiated" cell during the early phase of epithelial regeneration in denuded tracheal grafts. Griffonia simplicifolia I (GSI) lectin and flow cytometry were used for cell sorting. More than 98% of GSI-positive cells expressed plasma membrane alpha 1-3 terminal galactose (Gal), and 95% contained keratin 14 (K14), phenotypic markers for basal cells; < 1% were secretory or ciliated cells. Less than 2% of the GSI-negative cells expressed Gal or K14, but this fraction contained 16% ciliated cells and 54-79% secretory cells, dependent on whether periodic acid-Schiff staining or binding of an anti-secretory cell monoclonal antibody (RTE 12) was used as the criterion. Equal numbers of viable cells from either fraction were inoculated into denuded tracheal grafts, which were studied on days 1-14. At 24 h, greater numbers of GSI-negative than -positive cells were found attached to the graft wall; the keratin staining pattern of the attached cells was similar to that of the parent cell populations, but monoclonal antibody-detectable secretory and ciliated cell epitopes, originally present in the GSI-negative fraction, were lost. 5-Bromo-2'-deoxyuridine uptake was not seen at 24 h, but by 48 h all epithelial cells from both fractions entered the cell cycle. From 48 to 96 h, cells derived from either fraction were ultrastructurally indistinguishable; they were poorly differentiated and highly proliferative, and all expressed Gal and K14. A mature epithelium evolved from the poorly differentiated cells in both sets of grafts, but secretory and ciliated cells appeared earlier in grafts inoculated with GSI-negative cells. The results strongly suggest that in this model of tracheal epithelial regeneration both basal and secretory cells "dedifferentiated" into a similar highly proliferative phenotype from which a mucociliary epithelium "redifferentiated."
这些研究的目的是确定大鼠气管上皮（RTE）的基底细胞和分泌细胞是否均作为多能上皮祖细胞，以及在裸露气管移植物上皮再生的早期阶段，这两种细胞类型是否产生相似的“低分化”细胞。使用了西非单叶豆凝集素I（GSI）和流式细胞术进行细胞分选。超过98%的GSI阳性细胞表达质膜α1-3末端半乳糖（Gal），95%含有角蛋白14（K14），这是基底细胞的表型标志物；不到1%是分泌细胞或纤毛细胞。不到2%的GSI阴性细胞表达Gal或K14，但这部分细胞含有16%的纤毛细胞和54%-79%的分泌细胞，这取决于使用过碘酸希夫染色还是抗分泌细胞单克隆抗体（RTE 12）的结合作为标准。将来自任一细胞组分的等量活细胞接种到裸露的气管移植物中，并在第1至14天进行研究。在24小时时，发现附着在移植物壁上的GSI阴性细胞比阳性细胞更多；附着细胞的角蛋白染色模式与亲代细胞群体相似，但最初存在于GSI阴性组分中的单克隆抗体可检测的分泌细胞和纤毛细胞表位消失了。在24小时时未观察到5-溴-2'-脱氧尿苷摄取，但到48小时时，来自两个组分的所有上皮细胞都进入了细胞周期。从48小时到96小时，来自任一细胞组分的细胞在超微结构上无法区分；它们低分化且高度增殖，并且都表达Gal和K14。两组移植物中低分化细胞都演变成了成熟上皮，但在接种GSI阴性细胞的移植物中，分泌细胞和纤毛细胞出现得更早。结果强烈表明，在这个气管上皮再生模型中，基底细胞和分泌细胞都“去分化”为相似的高度增殖表型，从中“再分化”出黏液纤毛上皮。
