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An AAV9 coding for frataxin clearly improved the symptoms and prolonged the life of Friedreich ataxia mouse models.

Gérard C, Xiao X, Filali M, Coulombe Z, Arsenault M, Couet J, Li J, Drolet MC, Chapdelaine P, Chikh A, Tremblay JP - Mol Ther Methods Clin Dev (2014)

Bottom Line: This mutation leads to a reduced expression of frataxin.We have produced an adeno-associated virus (AAV)9 coding for human frataxin (AAV9-hFXN).The human frataxin protein was detected by ELISA in the heart, brain, muscles, kidney, and liver with the higher dose of virus in both mouse models.

View Article: PubMed Central - PubMed

Affiliation: Centre de Recherche du Centre Hospitalier Universitaire de Québec and Department of Molecular Medecine, Faculty of Medecine, Laval University , Québec, Canada.

ABSTRACT
Friedreich ataxia (FRDA) is a genetic disease due to increased repeats of the GAA trinucleotide in intron 1 of the frataxin gene. This mutation leads to a reduced expression of frataxin. We have produced an adeno-associated virus (AAV)9 coding for human frataxin (AAV9-hFXN). This AAV was delivered by intraperitoneal (IP) injection to young conditionally knockout mice in which the frataxin gene had been knocked-out in some tissues during embryogenesis by breeding them with mice expressing the Cre recombinase gene under the muscle creatine kinase (MCK) or the neuron-specific enolase (NSE) promoter. In the first part of the study, different doses of virus were tested from 6 × 10(11) v.p. to 6 × 10(9) v.p. in NSE-cre mice and all leading to an increase in life spent of the mice. The higher and the lower dose were also tested in MCK-cre mice. A single administration of the AAV9-hFXN at 6 × 10(11) v.p. more than doubled the life of these mice. In fact the MCK-cre mice treated with the AAV9-hFXN were sacrificed for further molecular investigations at the age of 29 weeks without apparent symptoms. Echography analysis of the heart function clearly indicated that the cardiac systolic function was better preserved in the mice that received 6 × 10(11) v.p. of AAV9-hFXN. The human frataxin protein was detected by ELISA in the heart, brain, muscles, kidney, and liver with the higher dose of virus in both mouse models. Thus, gene therapy with an AAV9-hFXN is a potential treatment of FRDA.

No MeSH data available.


Related in: MedlinePlus

Improved life survival of the neuron-specific enolase (NSE)-cre mice treated with AAV9-frataxin. (a) A score was created to evaluate daily the health of the NSE-cre mice. The score goes from 0, which corresponds to a normal phenotype, to 4, where the signs of discomfort (loss of weight, difficulties to walk or to feed) led to the sacrifice of the mice. The score started after weaning, at 21 days. The delay between the injection and a score of zero (no symptoms) was determined for all doses of AAV9-hFXN at 6 × 1011 v.p. (named AAV9-hFXN; n = 14), at 3 × 1011 v.p. (named d1/2; n = 7), at 6 × 1010 v.p. (named d1/10; n = 5), at 3 × 1010 v.p. (named d1/20; n = 5), at 1.2 × 1010 v.p. (named d1/50; n = 8), at 6 × 109 v.p. (named d1/100; n = 6). (b) The survival was also estimated for all these groups. The injection of AAV9-hFXN clearly improved the general health of the NSE-cre mice for all viral doses (†P ≤ 0.0001): AAV9-hFXN at 6 × 1011 v.p. (n = 18), at 3 × 1011 v.p. (n = 5), at 6 × 1010 v.p. (n = 4), at 3 × 1010 v.p. (n = 5), at 1.2 × 1010 v.p. (n = 8), at 6 × 109 v.p. (n = 6) when compared to the untreated mice (n = 58).
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fig3: Improved life survival of the neuron-specific enolase (NSE)-cre mice treated with AAV9-frataxin. (a) A score was created to evaluate daily the health of the NSE-cre mice. The score goes from 0, which corresponds to a normal phenotype, to 4, where the signs of discomfort (loss of weight, difficulties to walk or to feed) led to the sacrifice of the mice. The score started after weaning, at 21 days. The delay between the injection and a score of zero (no symptoms) was determined for all doses of AAV9-hFXN at 6 × 1011 v.p. (named AAV9-hFXN; n = 14), at 3 × 1011 v.p. (named d1/2; n = 7), at 6 × 1010 v.p. (named d1/10; n = 5), at 3 × 1010 v.p. (named d1/20; n = 5), at 1.2 × 1010 v.p. (named d1/50; n = 8), at 6 × 109 v.p. (named d1/100; n = 6). (b) The survival was also estimated for all these groups. The injection of AAV9-hFXN clearly improved the general health of the NSE-cre mice for all viral doses (†P ≤ 0.0001): AAV9-hFXN at 6 × 1011 v.p. (n = 18), at 3 × 1011 v.p. (n = 5), at 6 × 1010 v.p. (n = 4), at 3 × 1010 v.p. (n = 5), at 1.2 × 1010 v.p. (n = 8), at 6 × 109 v.p. (n = 6) when compared to the untreated mice (n = 58).

Mentions: A score from 0 to 4 was created to estimate the NSE-cre health (0 corresponding to no symptoms and 4 a state of health requiring immediate sacrifice; cf Supplementary Information). The NSE-cre mice were evaluated every day after the weaning (21 days) because of the great variability of the progression of the disease and mortality. When the mice were treated with the AAV9-hFXN, the score was around 1.5 at 21 days, while the average score was 2.0 for the untreated NSE-cre. However, the score of the treated NSE-cre mice decreased (i.e., they were less sick) over the following 3 days while the score of the untreated mice increased. The scores were significantly different between the two groups between 21 and 40 days. The time between the injection and the first score of 0 (i.e., no symptom) was also estimated. In average, 20 ± 5.8 days after the viral injection for 6 × 1011 v.p. and 15.7 ± 2.6 days for 6 × 109 v.p., all the symptoms of the disease had disappeared (Figure 3a). Some mice reached a 0 score but were later scored at 0.5 or 1. For the estimation of the time where no symptoms were detected, we considered the first time the mouse score reached 0. However, these NSE mice have later developed nervous system symptoms, their score rapidly increased and they had to be sacrificed for ethical concerns.


An AAV9 coding for frataxin clearly improved the symptoms and prolonged the life of Friedreich ataxia mouse models.

Gérard C, Xiao X, Filali M, Coulombe Z, Arsenault M, Couet J, Li J, Drolet MC, Chapdelaine P, Chikh A, Tremblay JP - Mol Ther Methods Clin Dev (2014)

Improved life survival of the neuron-specific enolase (NSE)-cre mice treated with AAV9-frataxin. (a) A score was created to evaluate daily the health of the NSE-cre mice. The score goes from 0, which corresponds to a normal phenotype, to 4, where the signs of discomfort (loss of weight, difficulties to walk or to feed) led to the sacrifice of the mice. The score started after weaning, at 21 days. The delay between the injection and a score of zero (no symptoms) was determined for all doses of AAV9-hFXN at 6 × 1011 v.p. (named AAV9-hFXN; n = 14), at 3 × 1011 v.p. (named d1/2; n = 7), at 6 × 1010 v.p. (named d1/10; n = 5), at 3 × 1010 v.p. (named d1/20; n = 5), at 1.2 × 1010 v.p. (named d1/50; n = 8), at 6 × 109 v.p. (named d1/100; n = 6). (b) The survival was also estimated for all these groups. The injection of AAV9-hFXN clearly improved the general health of the NSE-cre mice for all viral doses (†P ≤ 0.0001): AAV9-hFXN at 6 × 1011 v.p. (n = 18), at 3 × 1011 v.p. (n = 5), at 6 × 1010 v.p. (n = 4), at 3 × 1010 v.p. (n = 5), at 1.2 × 1010 v.p. (n = 8), at 6 × 109 v.p. (n = 6) when compared to the untreated mice (n = 58).
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig3: Improved life survival of the neuron-specific enolase (NSE)-cre mice treated with AAV9-frataxin. (a) A score was created to evaluate daily the health of the NSE-cre mice. The score goes from 0, which corresponds to a normal phenotype, to 4, where the signs of discomfort (loss of weight, difficulties to walk or to feed) led to the sacrifice of the mice. The score started after weaning, at 21 days. The delay between the injection and a score of zero (no symptoms) was determined for all doses of AAV9-hFXN at 6 × 1011 v.p. (named AAV9-hFXN; n = 14), at 3 × 1011 v.p. (named d1/2; n = 7), at 6 × 1010 v.p. (named d1/10; n = 5), at 3 × 1010 v.p. (named d1/20; n = 5), at 1.2 × 1010 v.p. (named d1/50; n = 8), at 6 × 109 v.p. (named d1/100; n = 6). (b) The survival was also estimated for all these groups. The injection of AAV9-hFXN clearly improved the general health of the NSE-cre mice for all viral doses (†P ≤ 0.0001): AAV9-hFXN at 6 × 1011 v.p. (n = 18), at 3 × 1011 v.p. (n = 5), at 6 × 1010 v.p. (n = 4), at 3 × 1010 v.p. (n = 5), at 1.2 × 1010 v.p. (n = 8), at 6 × 109 v.p. (n = 6) when compared to the untreated mice (n = 58).
Mentions: A score from 0 to 4 was created to estimate the NSE-cre health (0 corresponding to no symptoms and 4 a state of health requiring immediate sacrifice; cf Supplementary Information). The NSE-cre mice were evaluated every day after the weaning (21 days) because of the great variability of the progression of the disease and mortality. When the mice were treated with the AAV9-hFXN, the score was around 1.5 at 21 days, while the average score was 2.0 for the untreated NSE-cre. However, the score of the treated NSE-cre mice decreased (i.e., they were less sick) over the following 3 days while the score of the untreated mice increased. The scores were significantly different between the two groups between 21 and 40 days. The time between the injection and the first score of 0 (i.e., no symptom) was also estimated. In average, 20 ± 5.8 days after the viral injection for 6 × 1011 v.p. and 15.7 ± 2.6 days for 6 × 109 v.p., all the symptoms of the disease had disappeared (Figure 3a). Some mice reached a 0 score but were later scored at 0.5 or 1. For the estimation of the time where no symptoms were detected, we considered the first time the mouse score reached 0. However, these NSE mice have later developed nervous system symptoms, their score rapidly increased and they had to be sacrificed for ethical concerns.

Bottom Line: This mutation leads to a reduced expression of frataxin.We have produced an adeno-associated virus (AAV)9 coding for human frataxin (AAV9-hFXN).The human frataxin protein was detected by ELISA in the heart, brain, muscles, kidney, and liver with the higher dose of virus in both mouse models.

View Article: PubMed Central - PubMed

Affiliation: Centre de Recherche du Centre Hospitalier Universitaire de Québec and Department of Molecular Medecine, Faculty of Medecine, Laval University , Québec, Canada.

ABSTRACT
Friedreich ataxia (FRDA) is a genetic disease due to increased repeats of the GAA trinucleotide in intron 1 of the frataxin gene. This mutation leads to a reduced expression of frataxin. We have produced an adeno-associated virus (AAV)9 coding for human frataxin (AAV9-hFXN). This AAV was delivered by intraperitoneal (IP) injection to young conditionally knockout mice in which the frataxin gene had been knocked-out in some tissues during embryogenesis by breeding them with mice expressing the Cre recombinase gene under the muscle creatine kinase (MCK) or the neuron-specific enolase (NSE) promoter. In the first part of the study, different doses of virus were tested from 6 × 10(11) v.p. to 6 × 10(9) v.p. in NSE-cre mice and all leading to an increase in life spent of the mice. The higher and the lower dose were also tested in MCK-cre mice. A single administration of the AAV9-hFXN at 6 × 10(11) v.p. more than doubled the life of these mice. In fact the MCK-cre mice treated with the AAV9-hFXN were sacrificed for further molecular investigations at the age of 29 weeks without apparent symptoms. Echography analysis of the heart function clearly indicated that the cardiac systolic function was better preserved in the mice that received 6 × 10(11) v.p. of AAV9-hFXN. The human frataxin protein was detected by ELISA in the heart, brain, muscles, kidney, and liver with the higher dose of virus in both mouse models. Thus, gene therapy with an AAV9-hFXN is a potential treatment of FRDA.

No MeSH data available.


Related in: MedlinePlus