Shimizu T, Nettesheim P, Ramaekers F C, Randell S H
Department of Otorhinolaryngology, Mie University School of Medicine, Japan.
Am J Respir Cell Mol Biol. 1992 Jul;7(1):30-41. doi: 10.1165/ajrcmb/7.1.30.
Previous studies showed that Griffonia simplicifolia I-isolectin B4 (GS I-B4) and monoclonal antibodies (mAbs) against keratin 14 labeled basal cells in the adult rat trachea while other mAbs specifically stained secretory and/or ciliated cells. We used these "cell-type-specific" markers to study cellular differentiation during tracheal epithelial regeneration. Denuded tracheal grafts were inoculated with rat tracheal epithelial cells and were implanted in syngeneic hosts. Marker expression was correlated with the appearance of morphologically defined cell types. At 4 days, the epithelium was squamoid, one to three cell layers thick, and was apparently composed of a single morphologic cell type. Because this cell did not exhibit distinguishing features of any mature tracheal cell, we provisionally termed it the "poorly differentiated cell" (PD cell). PD cells expressed keratin 14 and GS I-B4 binding sites; they contained glycogen and had lipid droplets but did not react with secretory or ciliated cell-specific mAbs. At 7 days, areas of the epithelium were pseudostratified and secretory cell-specific markers were present at the apex of differentiating columnar cells; ultrastructurally, these cells resembled secretory cells in adult tracheas. Simultaneously, a few preciliated and ciliated cells appeared that expressed a ciliated cell-specific epitope. No cells were observed coexpressing secretory and ciliated cell markers. Basal cells also became recognizable on day 7. These expressed keratin 14 and GS I-B4 binding sites throughout the study. Newly appearing secretory and ciliated cells also expressed these two markers initially but lost them gradually as the mucociliary epithelium matured. In the tracheal graft model of epithelial regeneration, the PD cells were pivotal intermediates from which all differentiated cells developed. Basal cells continued to express the same markers as PD cells, which were gradually lost in secretory and ciliated cells as they acquired new sets of specific epitopes.
先前的研究表明，非洲猴面包树I型异凝集素B4（GS I-B4）和抗角蛋白14的单克隆抗体（mAb）可标记成年大鼠气管中的基底细胞，而其他单克隆抗体则特异性地染色分泌细胞和/或纤毛细胞。我们使用这些“细胞类型特异性”标记物来研究气管上皮再生过程中的细胞分化。将去上皮的气管移植物接种大鼠气管上皮细胞，并植入同基因宿主中。标记物表达与形态学定义的细胞类型的出现相关。在第4天，上皮呈鳞状，厚1至3层细胞，显然由单一形态学细胞类型组成。由于这种细胞未表现出任何成熟气管细胞的特征，我们暂时将其称为“低分化细胞”（PD细胞）。PD细胞表达角蛋白14和GS I-B4结合位点；它们含有糖原并具有脂滴，但不与分泌细胞或纤毛细胞特异性单克隆抗体反应。在第7天，上皮区域为假复层，分泌细胞特异性标记物出现在分化的柱状细胞顶端；超微结构上，这些细胞类似于成年气管中的分泌细胞。同时，出现了一些前纤毛细胞和纤毛细胞，它们表达纤毛细胞特异性表位。未观察到同时表达分泌细胞和纤毛细胞标记物的细胞。基底细胞在第7天也变得可识别。在整个研究过程中，它们都表达角蛋白14和GS I-B4结合位点。新出现的分泌细胞和纤毛细胞最初也表达这两种标记物，但随着黏液纤毛上皮成熟，它们逐渐丢失。在上皮再生的气管移植模型中，PD细胞是所有分化细胞发育而来的关键中间体。基底细胞继续表达与PD细胞相同的标记物，而这些标记物在分泌细胞和纤毛细胞获得新的特异性表位时逐渐丢失。
