Nonvectorial responses in photoreceptor cells stimulated by electrical fields

Abstract

The eye possesses various different types of electrical properties, and ocular cells are exposed to endogenous electrical fields (EFs) under natural conditions. Cellular behaviors that are regulated by EFs include vectorial (migration, orientation, and elongation) and nonvectorial responses (apoptosis and proliferation). The aim of this study was to investigate the nonvectorial responses of photoreceptor cells stimulated by EFs and to decipher the underlying molecular mechanisms. To investigate the effects of endogenous EFs on the cell behavior, we designed a customized electrical instrument that was mimetic of endogenous electrical activity. We observed that 60 and 90 mV/mm voltage gradients dramatically enhanced cell proliferation. Gene expression profiling, together with signaling pathway and gene ontology analyses, collectively demonstrated that the Ca2+-dependent extracellular signal-regulated kinase pathway is involved in cellular responses to EFs. Moreover, the results of our study clearly demonstrated that EFs promote photoreceptor cell proliferation via increased Ca2+ influx, which subsequently activates the ERK pathway. EF stimulation affects ionic fluxes in photoreceptor cells and is an important regulator of some important aspects of photoreceptor cell behavior. In conclusion, the findings of our study offer new insights on how EFs affect intracellular Ca2+, which further influences intracellular signal transduction and cell behavior.