Therefore, the present study revealed that TMEM119+ cells located in ONL during retinal degeneration may stand for a subpopulation of resident microglia which associated with photoreceptor apoptosis, along with the Iba1+ microglia/infiltrating macrophages, play a crucial role in releasing of pro-inflammatory cytokines, and amplify the neurodegenerative disease process. The gene discussed is TMEM119; the disease is retinal degeneration.