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Background: Recent advances in tissue regeneration approaches including 3D organoids, were based on various 3D organogenesis models. However, 3D models are generally technique-sensitive and time-consuming. Thus, we utilized an existing model of submandibular salivary gland (SMG) to modify a simple and highly reproducible in vitro 3D culture model of primary SMG cells self-organization into a well-developed cell spheroid inside Matrigel substrate. We used this model to observe the collective multicellular behavior during spheroid formation. Further, we applied various quantitative approaches including real-time live imaging and immune histochemical image analysis to dissect the cellular dynamics during tissue patterning., Results: On a time-scale of hours, we observed marked size and shape transformations in the developed 3D spheroid which resulted in a spatially-controlled growth differential from the canter to the periphery of the formed aggregates. Moreover, we investigated the effect of fibronectin (FN) on SMG cells self-organization using our simplified culture model. Interestingly, we discovered a novel role of FN in inducing duct-like elongation during initial stages of SMG bud formation., Conclusion: This in vitro model provides an excellent tool for analyzing the intercellular dynamics during early SMG tissue development as well as revealing a novel role of FN in SMG ductal expansion., (© 2019 Wiley Periodicals, Inc.)

Objective: Development of an artificial salivary gland will benefit patients with xerostomia after radiation therapy for upper respiratory cancer. The goal is to devise a three-dimensional (3D) culture system in which salivary cells differentiate into polarized acini that express essential biomarkers and directionally secrete alpha-amylase. Differentiated acini-like structures in a 3D biomaterial-based scaffold will mimic salivary gland functions., Study Design: Cells were seeded onto HA-based hydrogels containing PlnDIV peptide and allowed to differentiate into acini-like structures. Cell viability and phenotype were examined., Setting: Laboratory-based tissue procurement study., Subjects and Methods: Salivary gland tissue was obtained from patients undergoing surgery. Marker expression established the phenotype of salivary gland cells. Perlecan/HSPG2, an important component of the basement membrane, was highly expressed in salivary gland tissue. A culture system consisting of hyaluronic acid (HA) hydrogel and a coupled bioactive peptide derived from domain IV of perlecan (PlnDIV) was used. Prior studies demonstrated differentiation of acinar cells into lobular structures that mimicked intact glands when cultured on PlnDIV peptide-coated surfaces., Results: Lobular acini-like structures formed on hydrogels and expressed tight junction components such as zona occludens 1. Acini-like structures were stained for the presence of alpha-amylase. Live/dead staining revealed the presence of apoptotic cells in the center of the acini-like structures, indicative of lumen formation., Conclusion: A novel system supporting acini-like assembly in a 3D culture system was established. Presence of biomarkers and secretion of salivary enzymes confirms functionality in vitro. Future experiments will test the 3D system in an animal model., (Copyright 2010 American Academy of Otolaryngology-Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.)

The formation of acinar and ductal structures during epithelial tissue branching morphogenesis is not well understood. We report that in the mouse submandibular gland (SMG), acinar and ductal cell fates are determined early in embryonic morphogenesis with E-cadherin playing pivotal roles in development. We identified two morphologically distinct cell populations at the single bud stage, destined for different functions. The outer layer of columnar cells with organized E-cadherin junctions expressed the neonatal acinar marker B1 by E13.5, demonstrating their acinar fate. The interior cells initially lacked distinct E-cadherin junctions, but with morphogenesis formed cytokeratin 7 (K7) -positive ductal structures with organized E-cadherin junctions and F-actin filaments. Inhibition of E-cadherin function with either siRNA or function blocking antibody caused extensive apoptosis of ductal cells and aberrantly dilated lumens, providing the first evidence that E-cadherin regulates ductal lumen formation during branching morphogenesis of the salivary gland., (Copyright (c) 2008 Wiley-Liss, Inc.)