Abstract
Purpose :
To investigate tear duct anatomy, origin, developmental course, genetic and cellular determinants in mouse
Methods :
3D-reconstruction with immunostaining images of p63 and E-cadherin was used to illustrate tear duct anatomy, origin and developmental course. A knock-in GFP reporter was used to study Prickle 1 expression. Genetically engineered Prickle 1 null mutant mice were used to study Prickle 1 function in tear duct ontogenesis. Immunohistochemistry was performed on tissue sections with antibodies against basement membrane (BM) components, cytoskeleton and vesicle trafficking compartments. iPS-derived embryoid bodies (EBs) were used study basement membrane and cytoskeleton of visceral endodermal cells of in vitro differentiated EBs. Lentiviral vector carrying Prickle 1 gene was used to rescue BM of the mutant EBs.
Results :
We reconstructed the entire tear drainage system in mouse We report that primordial tear duct (PTD) originates from the junctional epithelium of the fusing maxillary and lateral nasal plate fated to conjunctiva, then separates from the original epithelium and is reshaped into branches as future canaliculi (CL) and nasolacrimal duct (NLD). We identified Prickle 1 as a hallmark for tear duct genesis, ablation of which led to stalled duct elongation due to impaired cell adhesion and disrupted BM. Cytoplasmic accumulation and/or ectopic secretion of BM components in the mutant PTD indicated altered cell polarity and protein trafficking defect along with altered actin fibers and microtubule tracks. We further generated in vitro differentiated embryoid bodies (EBs) from iPS cells, in which mutant EBs recapitulated the loss of BM phenotype of the PTD. Adding back Prickle 1 to the mutant EBs completely rescued the BM but not cell polarity.
Conclusions :
Taken together, our data suggests a general role of Prickle 1 in polarized BM secretion and deposition in different tissue contexts, which may be required for reestablishing epithelial polarity during tissue morphogenesis.
This is a 2020 ARVO Annual Meeting abstract.