Isolation, Tissue Localization, and Cellular Characterization of Progenitors Derived from Adult Human Salivary Glands

Abstract

Progenitors that can transdifferentiate into cells with hepatic or pancreatic phenotypes can be isolated from experimentally injured salivary glands of rodents. In this study, we isolated progenitors from "uninjured" adult human salivary glands by fluorescence-activated cell sorting using anti-CD49f and anti-Thy-1 antibodies. The sorted cells that were contained in the CD49f+/Thy-1+ fraction showed good proliferation on type I collagen. Single purified progenitor cells in plate culture expressed intracellular laminin, CD49f, Thy-1, and NGF receptor p75 (p75(NGFR)). Immunohistological analysis revealed the expression of Thy-1 and p75(NGFR) in stromal cells in the periductal area of the salivary gland. Under overconfluent conditions in plate culture, cell clusters containing insulin and glucagon-positive cells were occasionally formed. In order to produce differentiated cell clusters with uniform quality, we used a spherical culture system. Autonomous differentiation of cells in clusters into insulin-positive cells was induced in the spherical culture system. We measured C-peptide to estimate the endogenously produced insulin content. The C-peptide content of the spheroid bodies was low (3.5 ng/mg of protein), and they simultaneously expressed the early islet differentiation factor Nkx6.1, proendocrine gene neurogenin3, and ductal cell marker cytokeratin19. The progenitors existing in the interstitium of the salivary gland were able to transdifferentiate into cells with a pancreatic endocrine phenotype.

Immunohistochemical expression of stem cell markers in pheochromocytomas/paragangliomas is associated with SDHx mutations

“…In contrast, NGFR (p75 low affinity) displayed the second highest expression levels of all of the markers tested. NGFR has been described as being a potent MSC marker (36) and has been found to be expressed, for example, in the progenitor cells of human salivary glands (37). In the present study, NGFR expression was significantly more often associated with malignant PCCs/PGLs (5/12, or 42%) as compared to non-metastatic PCCs/PGLs (31/194, or 16%).…”

Neurotrophic factor GDNF promotes survival of salivary stem cells

“…We also evaluated CD49f (integrin α 6 , another putative marker for SSC and breast cancer SC) (8,22,27) and CD90.1 (Thy-1, a hematopoietic stem marker) (28). Because all CD24 + cells were also CD49f + (Supplemental Figure 1B) and CD90.1 + cells did not improve sphere formation over the CD24/c-Kit combination (Supplemental Figure 1C), neither marker was used in subsequent sorting.…”

“…Other markers that have been used to identify SSCs include Sca1 (5, 7), Thy-1 (8), integrin α 6 β 1 , (9,10), and CD34 (11). The first in vivo transplantation assay used murine c-Kit + cells from SMG.…”

Salivary Glands

“…Cell populations identified by the expression of markers often associated with stem cellsincluding cKit, Sca1 (Hisatomi et al 2004), integrin α6β1/ CD49f Sato et al 2007;David et al 2008), and CD24 hi /CD29…”