³H‐mannose utilization by fibroblasts of the periodontal ligament

Abstract

The synthesis, intracellular translocation, and secretion of mannose-containing glycoproteins(s) by periodontal ligament fibroblasts have been investigated by means of electron microscopic radioautography. Tritiated mannose was administered to young mice via jugular vein, and radioautographs were prepared at 5, 10, 20, and 35 minutes, 4 and 8 hours after injection. Analysis of electron microscopic radioautographs revealed a maximum labeling (94%) with 3H-mannose of the rough endoplasmic reticulum at 5 minutes. Labeling of the Golgi components started to increase from 10 minutes (14%) and reached a maximum level at 20 minutes (31.2%). At 35 minutes, secretion granules, dense bodies, profiles of intracellular collagen, and the cell surface were labeled. At 8 hours, most labelling (79.2%) was extracellular, and associated either with the collagenous matrix (43.7%) or the cell surface (35.5%). Cytoplasmic vesicles containing dense materials around collagen fibrils were also labeled at 8 hours. It is concluded that mannose is directly incorporated into the rough endoplasmic reticulum (RER), and that mannose-containing glycoprotein(s) are packaged in the Golgi apparatus into secretory granules. Mannose-containing glycoprotein(s) become distributed on the periodontal ligament (PDL) fibroblast cell surface, cytoplasmic dense bodies, and the extracellular matrix.

Mannose ameliorates experimental colitis by protecting intestinal barrier integrity

“…Free polymannose-type oligosaccharides incubated with liver cells have previously been shown to predominantly accumulate in lysosomes 46 . To quantify mannose uptake, radiolabeled probes have been used effectively 26 , 47 . We demonstrated that unmetabolized mannose is mainly located in the lysosome of colonic epithelial cells.…”

Radioautographic study of [3H]mannose utilization during cementoblast differentiation, formation of acellular cementuum, and development of periodontal ligament principal fibers

“…We have previously studied the utilization of [3H]mannose by periodontal ligament fibroblasts by electron microscopic radioautography (Cho and Garant, 1987). The routes and time periods for the intracellular translocation of mannose-containing glycoproteins in the periodontal ligament fibroblasts were found to be comparable to those for procollagen (Cho and Garant, 1981b, c).…”