title: Salivary gland progenitor cells induced by duct ligation differentiate into hepatic and pancreatic lineages.
abstract: Tissue damage can be assessed based on regenerative responses, including progenitor cell proliferation. In the salivary gland, tissue damage induced by ligation of main ducts leads to the disappearance of acinar cells and to marked proliferation of ductal cells. Reopening of the ducts leads to repopulation of acinar cells within 1 to 2 weeks, which suggests activation of tissue progenitor cells in a damaged state. Because submandibular glands derive from the endoderm and ectoderm, we investigated the possibility of the presence of endodermal progenitor cells. We cultured cells obtained from the ligated salivary gland and identified colonies of epithelium-like cells. We singled out and purified the cells by limited dilution, and one of the cells designated SGP-1 was used for further experiments. The SGP-1 expresses both alpha6beta1 integrin and cytoplasmic laminin. The hematopoietic stem cell marker CD34 and hepatic oval cell markers such as albumin, alpha-fetoprotein (AFP), and cytokeratin 19 are all negative. However, when SGP-1 cells were transplanted into the liver via the portal vein, these cells were integrated into hepatic trabecula and produced albumin. When SGP-1 cells formed clusters on type I collagen-coated dishes, they differentiated into endodermal lineage and 2 major types of clusters appeared: one contained cells positive for AFP and/or albumin (hepatic cluster) and the other positive for glucagon and/or insulin (pancreatic cluster). On laminin-coated dishes, SGP-1 selectively differentiated into hepatic-type cells. In conclusion, the multipotent progenitor cells isolated from the rat salivary gland have characteristics of tissue stem cells and can differentiate into cells of endodermal lineages.
authors.affiliation: Department of Pediatrics, School of Medicine, Kumamoto University, Kumamoto, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Okumura
authors.forename: Kimitoshi
authors.initials: K
authors.lastname: Nakamura
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Hisatomi
authors.forename: Koji
authors.initials: K
authors.lastname: Nagano
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Terada
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Sugiyama
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Umeyama
authors.forename: Kozo
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Fumio
authors.initials: F
authors.lastname: Endo
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D019070:Cell Lineage; D002469:Cell Separation; D002478:Cells, Cultured; D004707:Endoderm / Q000166:cytology; D022781:Hepatocytes / Q000166:cytology*; D008026:Ligation; D010179:Pancreas / Q000166:cytology*; D051381:Rats; D020332:Rats, Inbred LEC; D017207:Rats, Sprague-Dawley; D018987:Salivary Ducts; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology*; D013363:Submandibular Gland / Q000166:cytology*