Regulation of Myoepithelial Differentiation in 3-Dimensional Culture

Abstract

Myoepithelial cells serve as contractile units in exocrine glands, including mammary, salivary, and lacrimal glands, and their dysfunction negatively impacts secretory function. In spite of their importance, mechanisms that regulate myoepithelial differentiation are poorly defined. To study this process, we employed an established murine salivary gland epithelial cell line, mSG-PAC-1, that we previously demonstrated recapitulates aspects of acinar cell differentiation when cultured as spheroids. Here, we report that mSG-PAC1 spheroids can be induced towards a myoepithelial phenotype by manipulating culture conditions, resulting in the inhibition of expression of the acinar marker, AQP5, the upregulation of myoepithelial markers alpha-SMA, calponin, and the integrin beta4 subunit, as well as the acquisition of myoepithelial morphology. Transcriptome analysis indicated that YAP/TAZ target genes are also upregulated. We demonstrate that the transcriptional co-activator TAZ is expressed by the same cells that express alpha-SMA in the epithelial compartment of the differentiating murine salivary gland and by mSG-PAC1 cells under conditions that promote a myoepithelial phenotype. Furthermore, siRNA targeting TAZ expression in mSG-PAC1 spheroids diminishes expression of myoepithelial markers, implicating TAZ in their regulation. Thus, we have demonstrated mSG-PAC1 cells are a reliable tool to complement in vivo approaches to understand mechanisms that promote myoepithelial differentiation.

Tissue-engineered edible bird’s nests (TeeBN)

“…In comparison, the 2D culture accommodated a limited number of cells while the 3D encapsulation model had both lower viability and fewer proliferating cells. More interestingly, after 7 days of culture, the epithelial cells expressed the highest level of AQP5 (acinar cell-specific marker) and the lowest level of αSMA (myoepithelial marker) in the 3D-printed matrix [ 28 , 29 ] , among other cell cycle-related markers ( Figure 2L ) [ 30 ] . This trend was in favor of cell secretory capacity.…”