Abstract
The induction of heat shock response in the macula has been proposed as a useful therapeutic strategy for retinal neurodegenerative diseases by promoting proteostasis and enhancing protective chaperone mechanisms. We applied transpupillary 1064 nm long-duration laser heating to the mouse (C57Bl/6J) fundus to examine the heat shock response in vivo. The intensity and spatial distribution of heat shock protein (HSP) 70 expression along with the concomitant probability for damage were measured 24 h after laser irradiation in the mouse retinal pigment epithelium (RPE) as a function of laser power. Our results show that the range of heating powers for producing heat shock response while avoiding damage in the mouse RPE is narrow. At powers of 64 and 70 mW, HSP70 immunostaining indicates 90 and 100% probability for clearly elevated HSP expression while the corresponding probability for damage is 20 and 33%, respectively. Tunel staining identified the apoptotic regions, and the estimated 50% damaging threshold probability for the heating (ED50) was ~72 mW. The staining with Bestrophin1 (BEST1) demonstrated RPE cell atrophy with the most intense powers. Consequently, fundus heating with a long-duration laser provides an approachable method to develop heat shock-based therapies for the RPE of retinal disease model mice.
Highlights
Protein homeostasis, including the maintenance of correct folding and timely degradation of proteins, is essential to the function of cells
In order to survive under continuous exposure to environmental factors detrimental to protein function, cells employ stress response aiming at the restoration and preservation of proteostasis
The effect of the laser treatment on the activation of oxidative stress in the retinal pigment epithelium (RPE) flatmounts was investigated by Western blot for nitrotyrosine, a marker for pan-protein oxidation by nitric oxide mediated reactions by nitrosylation of tyrosine residues in proteins (Figure 1B)
Summary
Protein homeostasis, including the maintenance of correct folding and timely degradation of proteins, is essential to the function of cells. The heat shock response is one of the prosurvival activities in cells, whose principal aim is to increase the number of molecular chaperones to cope with enhanced protein misfolding and aggregation. The induction of heat shock response has been proposed as a useful therapeutic strategy for age-related neurodegenerative diseases by promoting proteostasis and enhancing protective chaperon mechanisms [5,6]. Dry or nonexudative age-related macular degeneration (AMD) is disease of the retina with a neurodegenerative component. It is strongly associated with the degeneration and death of retinal pigment epithelium (RPE) cells.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call