Limits...
Intravitreal administration of HA-1077, a ROCK inhibitor, improves retinal function in a mouse model of huntington disease.

Li M, Yasumura D, Ma AA, Matthes MT, Yang H, Nielson G, Huang Y, Szoka FC, Lavail MM, Diamond MI - PLoS ONE (2013)

Bottom Line: It is caused by an expanded polyglutamine tract in huntingtin (Htt).ROCK is thus a therapeutic target in HD.By targeting ROCK with a new inhibitor, and testing its effects in a novel in vivo model, these results validate the in vivo efficacy of a therapeutic candidate, and establish the feasibility of using the retina as a readout for CNS function in models of neurodegenerative disease.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Washington University in St. Louis, St. Louis, Missouri, USA.

ABSTRACT
Huntington disease (HD) is an inherited neurodegenerative disease that affects multiple brain regions. It is caused by an expanded polyglutamine tract in huntingtin (Htt). The development of therapies for HD and other neurodegenerative diseases has been hampered by multiple factors, including the lack of clear therapeutic targets, and the cost and complexity of testing lead compounds in vivo. The R6/2 HD mouse model is widely used for pre-clinical trials because of its progressive and robust neural dysfunction, which includes retinal degeneration. Profilin-1 is a Htt binding protein that inhibits Htt aggregation. Its binding to Htt is regulated by the rho-associated kinase (ROCK), which phosphorylates profilin at Ser-137. ROCK is thus a therapeutic target in HD. The ROCK inhibitor Y-27632 reduces Htt toxicity in fly and mouse models. Here we characterized the progressive retinopathy of R6/2 mice between 6-19 weeks of age to determine an optimal treatment window. We then tested a clinically approved ROCK inhibitor, HA-1077, administered intravitreally via liposome-mediated drug delivery. HA-1077 increased photopic and flicker ERG response amplitudes in R6/2 mice, but not in wild-type littermate controls. By targeting ROCK with a new inhibitor, and testing its effects in a novel in vivo model, these results validate the in vivo efficacy of a therapeutic candidate, and establish the feasibility of using the retina as a readout for CNS function in models of neurodegenerative disease.

Show MeSH

Related in: MedlinePlus

Intravitreal HA-1077 treatment improves cone-mediated ERG responses in R6/2 mice.Groups of R6/2 and WT littermate controls (n = 6–8 each) at 5 weeks of age were injected intravitreally in one eye with a single dose of liposomes loaded with either 40 µM or 100 µM HA-1077. The contralateral eye of each animal was injected with empty liposomes. ERG measurements were made 2 weeks later. A: Table of ERG responses. Amplitudes (µV) following intravitreal injection of empty or Fasudil-containing liposomes into the two eyes of wild-type and R6/2 mice. Values are indicated as Mean +/− S.E.M. B: In WT mice, HA-1077 had no significant effect on the ERG responses. C: In R6/2 mice, HA-1077 did not improve the rod-mediated scotopic responses, but both doses significantly improved the cone-mediated photopic b-wave and flicker ERG response amplitudes. Data are expressed as percentage improvement vs. the control liposome injected eye from each animal. *p<0.01; **p<0.001 by student t-test. Error bars represent S.E.M.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3569418&req=5

pone-0056026-g006: Intravitreal HA-1077 treatment improves cone-mediated ERG responses in R6/2 mice.Groups of R6/2 and WT littermate controls (n = 6–8 each) at 5 weeks of age were injected intravitreally in one eye with a single dose of liposomes loaded with either 40 µM or 100 µM HA-1077. The contralateral eye of each animal was injected with empty liposomes. ERG measurements were made 2 weeks later. A: Table of ERG responses. Amplitudes (µV) following intravitreal injection of empty or Fasudil-containing liposomes into the two eyes of wild-type and R6/2 mice. Values are indicated as Mean +/− S.E.M. B: In WT mice, HA-1077 had no significant effect on the ERG responses. C: In R6/2 mice, HA-1077 did not improve the rod-mediated scotopic responses, but both doses significantly improved the cone-mediated photopic b-wave and flicker ERG response amplitudes. Data are expressed as percentage improvement vs. the control liposome injected eye from each animal. *p<0.01; **p<0.001 by student t-test. Error bars represent S.E.M.

Mentions: We examined ERG responses measured in the two eyes simultaneously in 8 wild-type and 5 R6/2 mice and found, as expected, that within an individual animal, the left and right eyes were relatively similar, with an average variance of less than 10% (data not shown). We reasoned that comparisons between the right and left eye in an individual animal were likely to be much more useful to test compounds than a comparison of different groups of treated animals, since intra-animal tests benefit from an internal control. HA-1077 treatment had no significant effect on ERG amplitudes in wild-type mice (Fig. 6A,B). However it significantly improved photopic and flicker ERG response amplitudes by ∼40% (40 µM dose) and ∼60% (100 µM dose) in R6/2 mice (Fig. 6A,C). Thus, HA-1077 improved cone-mediated responses before any histological signs of retinal degeneration. As expected for the relatively short treatment period, we did not observe any changes in Htt pathology in the treated eyes.


Intravitreal administration of HA-1077, a ROCK inhibitor, improves retinal function in a mouse model of huntington disease.

Li M, Yasumura D, Ma AA, Matthes MT, Yang H, Nielson G, Huang Y, Szoka FC, Lavail MM, Diamond MI - PLoS ONE (2013)

Intravitreal HA-1077 treatment improves cone-mediated ERG responses in R6/2 mice.Groups of R6/2 and WT littermate controls (n = 6–8 each) at 5 weeks of age were injected intravitreally in one eye with a single dose of liposomes loaded with either 40 µM or 100 µM HA-1077. The contralateral eye of each animal was injected with empty liposomes. ERG measurements were made 2 weeks later. A: Table of ERG responses. Amplitudes (µV) following intravitreal injection of empty or Fasudil-containing liposomes into the two eyes of wild-type and R6/2 mice. Values are indicated as Mean +/− S.E.M. B: In WT mice, HA-1077 had no significant effect on the ERG responses. C: In R6/2 mice, HA-1077 did not improve the rod-mediated scotopic responses, but both doses significantly improved the cone-mediated photopic b-wave and flicker ERG response amplitudes. Data are expressed as percentage improvement vs. the control liposome injected eye from each animal. *p<0.01; **p<0.001 by student t-test. Error bars represent S.E.M.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3569418&req=5

pone-0056026-g006: Intravitreal HA-1077 treatment improves cone-mediated ERG responses in R6/2 mice.Groups of R6/2 and WT littermate controls (n = 6–8 each) at 5 weeks of age were injected intravitreally in one eye with a single dose of liposomes loaded with either 40 µM or 100 µM HA-1077. The contralateral eye of each animal was injected with empty liposomes. ERG measurements were made 2 weeks later. A: Table of ERG responses. Amplitudes (µV) following intravitreal injection of empty or Fasudil-containing liposomes into the two eyes of wild-type and R6/2 mice. Values are indicated as Mean +/− S.E.M. B: In WT mice, HA-1077 had no significant effect on the ERG responses. C: In R6/2 mice, HA-1077 did not improve the rod-mediated scotopic responses, but both doses significantly improved the cone-mediated photopic b-wave and flicker ERG response amplitudes. Data are expressed as percentage improvement vs. the control liposome injected eye from each animal. *p<0.01; **p<0.001 by student t-test. Error bars represent S.E.M.
Mentions: We examined ERG responses measured in the two eyes simultaneously in 8 wild-type and 5 R6/2 mice and found, as expected, that within an individual animal, the left and right eyes were relatively similar, with an average variance of less than 10% (data not shown). We reasoned that comparisons between the right and left eye in an individual animal were likely to be much more useful to test compounds than a comparison of different groups of treated animals, since intra-animal tests benefit from an internal control. HA-1077 treatment had no significant effect on ERG amplitudes in wild-type mice (Fig. 6A,B). However it significantly improved photopic and flicker ERG response amplitudes by ∼40% (40 µM dose) and ∼60% (100 µM dose) in R6/2 mice (Fig. 6A,C). Thus, HA-1077 improved cone-mediated responses before any histological signs of retinal degeneration. As expected for the relatively short treatment period, we did not observe any changes in Htt pathology in the treated eyes.

Bottom Line: It is caused by an expanded polyglutamine tract in huntingtin (Htt).ROCK is thus a therapeutic target in HD.By targeting ROCK with a new inhibitor, and testing its effects in a novel in vivo model, these results validate the in vivo efficacy of a therapeutic candidate, and establish the feasibility of using the retina as a readout for CNS function in models of neurodegenerative disease.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Washington University in St. Louis, St. Louis, Missouri, USA.

ABSTRACT
Huntington disease (HD) is an inherited neurodegenerative disease that affects multiple brain regions. It is caused by an expanded polyglutamine tract in huntingtin (Htt). The development of therapies for HD and other neurodegenerative diseases has been hampered by multiple factors, including the lack of clear therapeutic targets, and the cost and complexity of testing lead compounds in vivo. The R6/2 HD mouse model is widely used for pre-clinical trials because of its progressive and robust neural dysfunction, which includes retinal degeneration. Profilin-1 is a Htt binding protein that inhibits Htt aggregation. Its binding to Htt is regulated by the rho-associated kinase (ROCK), which phosphorylates profilin at Ser-137. ROCK is thus a therapeutic target in HD. The ROCK inhibitor Y-27632 reduces Htt toxicity in fly and mouse models. Here we characterized the progressive retinopathy of R6/2 mice between 6-19 weeks of age to determine an optimal treatment window. We then tested a clinically approved ROCK inhibitor, HA-1077, administered intravitreally via liposome-mediated drug delivery. HA-1077 increased photopic and flicker ERG response amplitudes in R6/2 mice, but not in wild-type littermate controls. By targeting ROCK with a new inhibitor, and testing its effects in a novel in vivo model, these results validate the in vivo efficacy of a therapeutic candidate, and establish the feasibility of using the retina as a readout for CNS function in models of neurodegenerative disease.

Show MeSH
Related in: MedlinePlus