Shh and ROCK1 modulate the dynamic epithelial morphogenesis in circumvallate papilla development

Abstract

In rodents, a circumvallate papilla (CVP) develops with dynamic changes in epithelial morphogenesis during early tongue development. Molecular and cellular studies of CVP development revealed that there would be two different mechanisms in the apex and the trench wall forming regions with specific expression patterns of Wnt11 and Shh. Molecular interactions were examined using in vitro organ culture with over-expression of Shh, important signalling molecules and various inhibitors revealed that there are two significant different mechanisms in CVP formation by Wnt11 and Shh expressions. Wnt, a well known key molecule to initiate taste papillae, would govern Rho activation and cytoskeleton formation in the apex epithelium of CVP. In contrast, Shh regulates the cell proliferation to differentiate taste buds and to invaginate the epithelium for development of von Ebner's gland (VEG). Based on these results, we suggest that these different molecular signalling cascades of Wnt11 and Shh would play crucial roles in specific morphogenesis and pattern formation of CVP during early mouse embryo development.

Dissecting the PCP pathway: One or more pathways?

“…The function of Rac is unclear but may act through regulation of adherens junctions or the formation of lamellipodia during cell displacement, by analogy with its role in other models of cell motility [42]. Further evidence linking the Rho/ROCK/Myosin II module to Fz-Dsh has now accumulated from other analyses of mesodermal morphogenesis, and also from studies of epithelial morphogenesis during gastrulation in sea urchin, nematode and vertebrate epithelial appendage formation [43][44][45][46][47][48]. It is important to note, however, that the Rho/ROCK/Myosin II cassette is certainly not Wnt/Fz specific, and can be activated downstream of many signalling factors including Eph, Hedgehog or EGF [49][50][51].…”

Importance of region-specific epithelial rearrangements in mouse rugae development

“…Procedures for in vitro organ culture were carried out at E13 for 2 days as described previously (Chou et al 2004;Kim et al 2009). Dissected specimens were cultivated in 8 ml BGJb medium containing 1% penicillin-streptomycin for 2 days in a 50-ml penicillin bottle.…”

“…DiI (Molecular Probes, Eugene, Ore., USA) is a vital, highly fluorescent, lipophilic dye belonging to the carbocyanine dye family (Chou et al 2004;Kim et al 2009). After the DiI micro-injections had been injected into the designated regions at the E13 palate, the migration patterns of the DiI-labeled cells were observed, after a 48-h cultivation period, by fluorescence microscopy (MZ-FL16FA; Leica, Germany).…”

Reciprocal interactions of Fgf10/Fgfr2b modulate the mouse tongue epithelial differentiation

“…Whole-mount in situ hybridizations were performed as previously described (Kim et al 2009) by using standard protocols. Mouse DNA Fgf7, Fgf10 and Fgr2b plasmids were used as templates for the synthesis of DIG-labeled RNA probes, as kindly provided by Dr. Y.-P. Chen (Tulane University, USA).…”

“…For treatments of AS-ODNs, E12.5 embryos were dissected and cultured in a medium containing 10% fetal bovine serum for 2 and 3 days according to the in vitro rolling organ culture method described previously (Kim et al 2009). For protein-soaked bead implantations, modified Trowell's culture method was employed at E13.5 for 1 and 2 days (Kim et al 2003).…”