Salivary Gland ECM Hydrogel Has Tissue-Specific Effects on Par-C5 Cells

Objectives: Saliva plays an essential role in maintaining oral tissues, including the dentition, and salivary gland (SG) dysfunction causes significant risks to oral/general health and leads to a compromised quality of life. Currently, there are no cures for SG dysfunction. Tissue engineering of the SG using SG cells have shown promise, but our understanding of the SG microenvironment (niche) which regulates SG cell growth is lacking. The aim of this study was to determine the effect of a porcine SG extracellular matrix (ECM) hydrogel on SG cell proliferation and differentiation.
Methods: A porcine submandibular gland hydrogel (pSMG-hydrogel) was prepared by decellularizing the tissue with either 8mM CHAPS containing 1.0M NaCl, 25mM EDTA and proteinase inhibitors or 1% SDS buffer followed by homogenization, lyophilization, pepsin digestion, and neutralization. Total protein content of the hydrogel was measured with Bradford reagent; collagen content was estimated using Sircol reagent. Rat Par-C5 cells (a SG cell line) were cultured on hydrogel-coated tissue culture plates (TCP). Cell proliferation and expression of differentiation biomarkers were tested using Alamar Blue and RT-qPCR, respectively.
Results: Complete decellularization of pSMG was demonstrated by H&E and immunofluorescence staining. The collagen content of the hydrogel was 30% of the total protein. Cell viability and proliferation of cells on the pSMG-hydrogel were similar to that on Matrigel®-coated or TCP plates. Expression of SG cell differentiation biomarkers, i.e., Amylase, Mist1, Claudin10, Keratin10, Mucin10 and Proline rich protein (Prp15), was the same on the pSMG-hydrogel and Matrigel® and higher than that on TCP.
Conclusions: The pSMG ECM hydrogel had an effect on SG cell growth/differentiation that was similar to Matrigel®. Therefore, our results suggest that the native pSMG-derived hydrogel might replicate the SG microenvironment and be useful for future stem cell-based therapies for SG dysfunction.