The heat-shock response co-inducer arimoclomol protects against retinal degeneration in rhodopsin retinitis pigmentosa.
Retinitis pigmentosa (RP) is a group of inherited diseases that cause blindness due to the progressive death of rod and cone photoreceptors in the retina. There are currently no effective treatments for RP. Inherited mutations in rhodopsin, the light-sensing protein of rod photoreceptor cells, are the most common cause of autosomal-dominant RP. The majority of mutations in rhodopsin, including the common P23H substitution, lead to protein misfolding, which is a feature in many neurodegenerative disorders. Previous studies have shown that upregulating molecular chaperone expression can delay disease progression in models of neurodegeneration. Here, we have explored the potential of the heat-shock protein co-inducer arimoclomol to ameliorate rhodopsin RP. In a cell model of P23H rod opsin RP, arimoclomol reduced P23H rod opsin aggregation and improved viability of mutant rhodopsin-expressing cells. In P23H rhodopsin transgenic rat models, pharmacological potentiation of the stress response with arimoclomol improved electroretinogram responses and prolonged photoreceptor survival, as assessed by measuring outer nuclear layer thickness in the retina. Furthermore, treated animal retinae showed improved photoreceptor outer segment structure and reduced rhodopsin aggregation compared with vehicle-treated controls. The heat-shock response (HSR) was activated in P23H retinae, and this was enhanced with arimoclomol treatment. Furthermore, the unfolded protein response (UPR), which is induced in P23H transgenic rats, was also enhanced in the retinae of arimoclomol-treated animals, suggesting that arimoclomol can potentiate the UPR as well as the HSR. These data suggest that pharmacological enhancement of cellular stress responses may be a potential treatment for rhodopsin RP and that arimoclomol could benefit diseases where ER stress is a factor.
Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK.
D A
DA
Parfitt
Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK.
M
M
Aguila
Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK.
C H
CH
McCulley
Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK.
D
D
Bevilacqua
Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK.
H F
HF
Mendes
Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK.
D
D
Athanasiou
Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK.
S S
SS
Novoselov
Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK.
N
N
Kanuga
Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK.
P M
PM
Munro
Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK.
P J
PJ
Coffey
Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK.
B
B
Kalmar
1] Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK [2] MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, Queen Square, London, UK.
L
L
Greensmith
Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, UK.
M E
ME
Cheetham
D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D019610:Cytoprotection; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004596:Electroretinography; D018869:Heat-Shock Response / Q000187:drug effects*; D006801:Humans; D006898:Hydroxylamines / Q000494:pharmacology*; D009154:Mutation; D020419:Photoreceptor Cells, Vertebrate / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D055647:Rats, Transgenic; D012162:Retinal Degeneration / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D012174:Retinitis Pigmentosa / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D012243:Rhodopsin / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection; D056811:Unfolded Protein Response / Q000187:drug effects; D014785:Vision, Ocular / Q000187:drug effects
D006898:Hydroxylamines; D012243:Rhodopsin; C486387:arimoclomol