Blue light-emitting diode irradiation promotes transcription factor EB-mediated lysosome biogenesis and lysosomal cell death in murine photoreceptor-derived cells.

Exposure to blue light from light-emitting diodes (LEDs) is a source of damage for human eyes in today's modern life. Although it is well known that blue light can cause cellular damage and death, the molecular mechanism underlying this is still not fully understood. Here, we demonstrated that exposure to blue LED light increased lysosome levels and perinuclear cluster formation in 661W murine photoreceptor-derived cells. Irradiation with blue LED light promoted the nuclear transport of transcription factor EB (TFEB) and a subsequent increase in lysosomal-related gene expression. Moreover, blue LED light induced morphological changes in lysosomal structure and lysosomal membrane permeabilization (LMP). These effects were suppressed by an antioxidant, N-acetylcysteine (NAC). Finally, a calcium ion chelator, BAPTA-AM, attenuated blue LED light-induced lysosomal biogenesis and cell death. Taken together, these findings suggest that oxidative stress under blue LED light increases lysosome levels via the TFEB pathway in a calcium-dependent manner, resulting in the accumulation of damaged lysosomes and subsequently lysosomal cell death. Our results imply that lysosomal homeostasis plays a key role in the maintenance of eye function and the progression of retinal diseases.