New focus on alpha-crystallins in retinal neurodegenerative diseases

The crystallin proteins were initially identified as structural proteins of the ocular lens and have been recently demonstrated to be expressed in normal retina. They are dramatically upregulated by a large range of retinal diseases including diabetic retinopathy, age-related macular degeneration, uveitis, trauma and ischemia. The crystallin family of proteins is composed of alpha-, beta- and gamma-crystallin. Alpha-crystallins, which are small heat shock proteins, have received substantial attention recently. This review summarizes the current knowledge of alpha-crystallins in retinal diseases, their roles in retinal neuron cell survival and retinal inflammation, and the regulation of their expression and activity. Their potential role in the development of new treatments for neurodegenerative diseases is also discussed.

Research highlights
► Alpha-crystallins are upregulated in a large number of retinal diseases.
► Alpha-crystallins regulate retinal neuron cell death.
► Crystallins are also involved in inflammation and angiogenesis regulation.
► Retinal crystallins are regulated at multiple levels in pathological conditions.
► Retinal crystallins could be a crucial target or player in new retinal disease therapies.