Overview of heat shock protein ocular location and involvement in diseases of the eye.
Hsp subtype
Diseases
Cornea
Hsp27 Hsp60 Hsp70 Hsp72 Hsp90
(i) Epithelial wound healing: Hsp70 has been suggested to be involved in wound healing of the cornea. (ii) UV radiation: the level of Hsp27 is increased in the corneal epithelium following UVB radiation and is suggested to play a protective role against such damaging radiation.
Lens
Hsp27 Alpha-crystallin Hsp40 Hsp70
(i) Cataract: Hsps have been suggested to play a significant role in cataract development most likely by either mutation of alpha-crystallin or by alpha-crystallin degeneration with age.
Retina
Hsp27 Hsp70 Hsp40 Hsp84 Hsp86 Hsp90
(i) Age-related macular degeneration (AMD): Hsp27 and alpha-crystallin are suggested to play a role in AMD after having been found to be induced and elevated in retina samples affected by the disease. (ii) Diabetic retinopathy. (iii) Glaucoma, light injury: possibly neuroprotective.
Choroid
Hsp-Beta1
Other
(i) Ocular cancer: various ocular cancers are associated with increased levels of Hsps. It is not clear whether Hsps play a role in cancer development or are increased as a result of secondary homeostatic mechanisms. (a) Retinoblastoma: high expression of alpha-crystallin, Hsp70, and -90 have been found. (b) Uveal melanoma: increased levels of Hsp-beta1, -60, -70, and -90 have been detected. Hsp27 has been found increased, and low or not detectable.
(ii) Glaucoma: Hsp27, -60, -70, and -72 have been found increased in glaucomatous eyes and pressure induced ischemic rodent eyes. However, it is unclear if Hsps confer cellular protection.
