In vivo, Ex Vivo, and In Vitro Approaches to Study Intermediate Filaments in the Eye Lens

The role of the eye lens is to focus light into the retina. To perform this unique function, the ocular lens must be transparent. Previous studies have demonstrated the expression of vimentin, BFSP1, and BFSP2 in the eye lens. These intermediate filament (IF) proteins are essential to the optical properties of the lens. They are also important to its biomechanical properties, to the shape of the lens fiber cells, and to the organization and function of the plasma membrane. The eye lens is an iconic model in developmental studies, as a result different vertebrate models, including zebrafish, have been developed to study lens formation. In the present chapter, we have summarized the new approaches and the more breakthrough models (e.g., iPSc) that can be used to study the function of IFs in the ocular lens. We have presented three different groups of models. The first group includes in vitro models, where IFs can be studied and manipulated in lens cell cultures. The second includes ex vivo models. These replicate better the complex lens cell differentiation processes and the role(s) played by IFs. The third class is the in vivo models, and here, we have focused on Zebrafish and new imaging approaches using selective plane illumination microscopy. Finally, we present protocols on how to use these lens models to study IFs.