Abstract
Purpose :
Dramatic morphological change from a thin monolayer of cuboidal lens epithelial cells (LECs) to multiple shells of elongated lens fiber cells (LFCs), is a hallmark of ocular lens differentiation and critical for maintaining lens transparency, as lens structure basically determines its function. However, the concise molecular mechanism underlying this process remains unknown. Here, using an in-vitro induction model of lens differentiation, we postulated that microtubule-severing enzyme, katanin family may play an important role in lens fiber elongation.
Methods :
The mouse lens epithelial cells, αTN4-1 cells, were treated with basic fibroblast growth factor (bFGF) at a high concentration. Cell morphology was observed under a phase contrast microscope. Cytoskeleton alterations were determined by immunocytochemistry staining (ICC). The expression levels of differentiation-specific marker β-crystallins and several important transcription factors (sox2, c-Maf, pax6, prox1) were detected using semi-quantitative real-time PCR and western blotting. Katanin family members and tubulins were also tested for expression levels and localization.
Results :
After a prolonged culture at high concentration of bFGF, mouse αTN4-1 cells were induced to elongate and migrate to form lentoid bodies consisting of multi-layered LFCs. Compared to baseline control group, this in-vitro induction model recapitulated characteristics resembling lens differentiation in vivo, including accumulation of β-crystallins and increased expression of elongation-relevant transcription factors. Katanin family members, were revealed to have similar expression and localization patterns with tubulins, and other cytoskeletal elements during lens elongation, which correlated with morphological changes as well.
Conclusions :
Our experiment confirms that lens differentiation is a highly coordinated process with precise alignment of LFCs and synchronized reorganization of cytoskeleton. The results are consistent with our hypothesis that katanin family may contribute to LFCs elongation during lens differentiation. But further investigations are needed to unveil the specific functions of katanin and key transcription factors regulating this process.
This is a 2020 ARVO Annual Meeting abstract.