Y-27632 enables long-term expansion of mouse submandibular gland epithelial cells via inactivation of TGF-β1/CTGF/p38 and ROCK2/JNK signaling pathway.

Objectives: This study aimed to investigate the effects of Y-27632 on the long-term maintainence of mouse submandibular epithelial cells (SG-Epis) in vitro and to elucidate the underlying mechanisms.

Methods: The role of the Rho-associated kinase (ROCK) inhibitor Y-27632 in maintaining SG-Epis and its underlying mechanisms were evaluated by examining the in vitro expansion of mouse SG-Epis. Changes in key cellular characteristics, such as proliferation, long-term expansion, and mRNA and protein expression, were assessed in the presence or absence of Y-27632.

Results: Treatment with Y-27632 significantly enhanced the proliferative potential of SG-Epis, preserving Krt8 and Krt14 expression over 17 passages. In the absence of Y-27632, SG-Epis lost their epithelial morphology. However, Y-27632 treatment maintained the epithelial morphology and downregulated mRNA levels of Tgf-β1, Ctgf, and Rock2. Treatment with TGF-β1 indicated that TGF-β/CTGF/p38 signaling is responsible for the maintenance of SG-Epis, while RNA interference studies revealed that ROCK2/c-Jun N-terminal kinase (JNK) signaling is also crucial for SG-Epis proliferation and maintenance.

Conclusions: The TGF-β1/CTGF/p38 and ROCK2/JNK signaling pathways are responsible for SG-Epis proliferation, and Y-27632 treatment effectively inactivates these pathways, enabling long-term in vitro maintenance of SG-Epis. The culture method utilizing Y-27632 provides an effective approach for the in vitro expansion of SG-Epis.