Salivary function in mammals may be defective for various reasons, such as aging, Sjogren's syndrome or radiation therapy in head and neck cancer patients. Recently, tissue-specific stem cell therapy has attracted public attention as a next-generation therapeutic reagent. In the present study, we isolated tissue-specific stem cells from the human submandibular salivary gland (hSGSCs). To efficiently isolate and amplify hSGSCs in large amounts, we developed a culture system (lasting 4-5 weeks) without any selection. After five passages, we obtained adherent cells that expressed mesenchymal stem cell surface antigen markers, such as CD44, CD49f, CD90 and CD105, but not the hematopoietic stem cell markers, CD34 and CD45, and that were able to undergo adipogenic, osteogenic and chondrogenic differentiation. In addition, hSGSCs were differentiated into amylase-expressing cells by using a two-step differentiation method. Transplantation of hSGSCs to radiation-damaged rat salivary glands rescued hyposalivation and body weight loss, restored acinar and duct cell structure, and decreased the amount of apoptotic cells. These data suggest that the isolated hSGSCs, which may have characteristics of mesenchymal-like stem cells, could be used as a cell therapy agent for the damaged salivary gland.
Amylases/genetics/metabolism ; Animals ; Antigens, CD/genetics/metabolism ; Apoptosis ; Cell Differentiation ; Humans ; Male ; Mesenchymal Stromal Cells/*cytology/metabolism ; Radiation Injuries, Experimental ; Rats ; Rats, Wistar ; *Regeneration ; Salivary Glands/cytology/injuries/physiology/*surgery ; *Salivation ; *Stem Cell Transplantation

We report the case of a patient who presented with cystic lymphoid hyperplasia of the right parotid gland as the index diagnosis of HIV infection. Histological examination of the excised parotid gland revealed a solid-cystic lymphoepithelial lesion with a non-keratinous squamous epithelium, which grew into the lymphoid component via anastomosing cords and islands. These anastomosing cords and islands contained variably abundant B cells, several subepithelial multinucleated histiocytes, salivary ducts infiltrated by small lymphocytes, and a dense lymphoid infiltrate containing lymphoid follicles with enlarged, irregular germinal centres.
Adult ; B-Lymphocytes ; cytology ; Biopsy ; Epithelial Cells ; cytology ; Epithelium ; metabolism ; HIV Infections ; diagnosis ; Humans ; Hyperplasia ; pathology ; virology ; Immunohistochemistry ; Lymphocytes ; cytology ; Male ; Parotid Gland ; pathology ; virology ; Salivary Glands ; pathology ; Tomography, X-Ray Computed

Lysophosphatidic acid (LPA) is a bioactive lysophospholipid involved in numerous physiological responses. However, the expression of LPA receptors and the role of the Hippo signaling pathway in epithelial cells have remained elusive. In this experiment, we studied the functional expression of LPA receptors and the associated signaling pathway using reverse transcriptase-PCR, microspectrofluorimetry, western blotting and immunocytochemistry in salivary gland epithelial cells. We found that LPA receptors are functionally expressed and involved in activating the Hippo pathway mediated by YAP/TAZ through Lats/Mob1 and RhoA/ROCK. Upregulation of YAP/TAZ-dependent target genes, including CTGF, ANKRD1 and CYR61, has also been observed in LPA-treated cells. In addition, based on data suggesting that tumor necrosis factor (TNF)-alpha induces cell apoptosis, LPA upregulates TNF-induced caspase-3 and cleaved Poly(ADP-ribose)polymerase (PARP). However, small interfering RNA treatment to Yes-associated protein (YAP) or transcriptional co-activator with a PDZ-binding motif (TAZ) significantly decreased TNF-alpha- and LPA-induced apoptosis, suggesting that YAP and TAZ modulate the apoptotic pathway in salivary epithelial cells.
Adaptor Proteins, Signal Transducing/genetics/metabolism ; *Apoptosis ; Cell Line ; Epithelial Cells/*cytology/metabolism ; Gene Expression Regulation ; Humans ; Intracellular Signaling Peptides and Proteins/genetics/metabolism ; Lysophospholipids/*metabolism ; Phosphoproteins/genetics/metabolism ; Protein-Serine-Threonine Kinases/*metabolism ; RNA Interference ; RNA, Small Interfering/genetics ; Receptors, Lysophosphatidic Acid/genetics/*metabolism ; Salivary Glands/*cytology/metabolism ; *Signal Transduction ; Tumor Necrosis Factor-alpha/metabolism ; rho-Associated Kinases/metabolism ; rhoA GTP-Binding Protein/metabolism