Embodiments of the invention provide methods of preventing or treating detrimental epithelial cell proliferation, loss of epithelial cell differentiation, age-related macular degeneration and/or proliferative vitreal retinopathy in an individual comprising administering to an individual in need thereof an effective amount of miR 204, an effective amount of miR 211, or an effective amount of a mixture of miR 204 and miR 211. A further embodiment of the invention provides a method of facilitating the transport of a substance across an epithelium in an individual comprising administrating to an individual an effective amount of anti-miR 204, an effective amount of anti-miR 211, or an effective amount of a mixture of anti-miR 204 and anti-miR 211. Additional embodiments of the invention include pharmaceutical compositions of miR 204 and/or miR 211 and pharmaceutical compositions of anti-miR 204 and/or anti-miR 211.
