Salivary gland stem cells (SGSCs) are potential cell sources for the treatment of salivary gland diseases. The control of cell survival is an essential factor for applying stem cells to regenerative medicine or stem cell-based research. The purpose of this study was to investigate the effects of the ROCK inhibitor Y-27632 on the survival of SGSCs and its underlying mechanisms. SGSCs were isolated from mouse submandibular glands and cultured in suspension. Treatment with Y-27632 restored the viability of SGSCs that was significantly decreased during isolation and the subsequent culture. Y-27632 upregulated the expression of anti-apoptotic protein BCL-2 in SGSCs and, in the apoptosis assay, significantly reduced apoptotic and necrotic cell populations. Matrigel was used to mimic the extracellular environment of an intact salivary gland. The expression of genes regulating apoptosis and the ROCK signaling pathway was significantly reduced when SGSCs were embedded in Matrigel. SGSCs cultured in Matrigel and treated with Y-27632 showed no difference in the total numbers of spheroids and expression levels of apoptosis-regulating genes. Matrigel-embedded SGSCs treated with Y-27632 increased the number of spheroids with budding structures and the expression of acinar cell-specific marker AQP5. We demonstrate the protective effects of Y-27632 against dissociation-induced apoptosis of SGSCs during their culture in vitro.

Hyaline cartilage is a tissue of very low regenerative capacity because of its histology and limited nutrient supply. Cell-based therapies have been spotlighted in the regeneration of damaged cartilage. Dental pulp stem cells (DPSCs) are multipotent and are easily accessible for therapeutic purposes. In human gastrointestinal tracts, Enterococcus faecium is a naturally occurring commensal species of lactic acid bacteria. In this work, the human DPSCs were differentiated into chondrocytes using a chondrogenic differentiation medium with or without L-15 extract. We observed that chondrogenic differentiation improved in an E. faecium L-15 extract (L-15)-treated DPSC group via evaluation of chondrogenic-marker mRNA expression levels. In particular, we found that L-15 treatment promoted early-stage DPSC differentiation. Cells treated with L-15 were inhibited at later stages and were less likely to transform into hypertrophic chondrocytes. In L-15-treated groups, the total amount of cartilage extracellular matrix increased during the differentiation process. These results suggest that L-15 promotes chondrogenic differentiation, and that L-15 may be used for cartilage repair or cartilage health supplements. To our knowledge, this is the first report demonstrating the beneficial effect of L-15 treatment on chondrogenic differentiation.