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Pharmacological enhancement of mGlu1 metabotropic glutamate receptors causes a prolonged symptomatic benefit in a mouse model of spinocerebellar ataxia type 1.

Notartomaso S, Zappulla C, Biagioni F, Cannella M, Bucci D, Mascio G, Scarselli P, Fazio F, Weisz F, Lionetto L, Simmaco M, Gradini R, Battaglia G, Signore M, Puliti A, Nicoletti F - Mol Brain (2013)

Bottom Line: Spinocerebellar ataxia type 1 (SCA1) is a genetic disorder characterized by severe ataxia associated with progressive loss of cerebellar Purkinje cells.A single injection of Ro0711401 improved motor symptoms for several days, and no tolerance developed to the drug.The prolonged symptomatic benefit caused by Ro0711401 outlasted the time of drug clearance from the cerebellum, and was associated with neuroadaptive changes in the cerebellum, such as a striking reduction of the ectopically expressed mGlu5 receptors in Purkinje cells, increases in levels of total and Ser880-phosphorylated GluA2 subunit of AMPA receptors, and changes in the length of spines in the distal dendrites of Purkinje cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: I,R,C,C,S, Neuromed, Pozzilli, Italy. ferdinandonicoletti@hotmail.com.

ABSTRACT

Background: Spinocerebellar ataxia type 1 (SCA1) is a genetic disorder characterized by severe ataxia associated with progressive loss of cerebellar Purkinje cells. The mGlu1 metabotropic glutamate receptor plays a key role in mechanisms of activity-dependent synaptic plasticity in the cerebellum, and its dysfunction is linked to the pathophysiology of motor symptoms associated with SCA1. We used SCA1 heterozygous transgenic mice (Q154/Q2) as a model for testing the hypothesis that drugs that enhance mGlu1 receptor function may be good candidates for the medical treatment of SCA1.

Results: Symptomatic 30-week old SCA1 mice showed reduced mGlu1 receptor mRNA and protein levels in the cerebellum. Interestingly, these mice also showed an intense expression of mGlu5 receptors in cerebellar Purkinje cells, which normally lack these receptors. Systemic treatment of SCA1 mice with the mGlu1 receptor positive allosteric modulator (PAM), Ro0711401 (10 mg/kg, s.c.), caused a prolonged improvement of motor performance on the rotarod and the paw-print tests. A single injection of Ro0711401 improved motor symptoms for several days, and no tolerance developed to the drug. In contrast, the mGlu5 receptor PAM, VU0360172 (10 mg/kg, s.c.), caused only a short-lasting improvement of motor symptoms, whereas the mGlu1 receptor antagonist, JNJ16259685 (2.5 mg/kg, i.p.), further impaired motor performance in SCA1 mice. The prolonged symptomatic benefit caused by Ro0711401 outlasted the time of drug clearance from the cerebellum, and was associated with neuroadaptive changes in the cerebellum, such as a striking reduction of the ectopically expressed mGlu5 receptors in Purkinje cells, increases in levels of total and Ser880-phosphorylated GluA2 subunit of AMPA receptors, and changes in the length of spines in the distal dendrites of Purkinje cells.

Conclusions: These data demonstrate that pharmacological enhancement of mGlu1 receptors causes a robust and sustained motor improvement in SCA1 mice, and lay the groundwork for the development of mGlu1 receptor PAMs as novel "cerebellum-specific", effective, and safe symptomatic drugs for the treatment of SCA1 in humans.

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Acute treatment with the mGlu1 receptor PAM, Ro0711401, improves motor performance in symptomatic SCA1 mice. Effect of Ro0711401 on the rotarod in symptomatic SCA1 mice with mild motor impairment (A); values are means ± S.E.M. of 4 mice per group. *p < 0.05 vs. corresponding values at time 0; Two-way ANOVA for repeated measures + Fisher’s LSD: F(3,21) = 7.621 and F(1,21) = 10.176 for time and treatment, respectively; and in wild-type littermates (B); data are means ± S.E.M. of 7 mice per group. Lack of effect of JNJ16259685 in SCA1 mice with mild motor impairment and wild-type (C), where data are means ± S.E.M. of 4 mice per group; *p < 0.05 vs. respective values at time 0. Two-way ANOVA for repeated measures + Fisher’s LSD; F(3,18) = 34.38 and F(1,18) = 7.24 for time and treatment, respectively. Effect of Ro0711401 in symptomatic SCA1 mice with severe motor impairment (D); values are means ± S.E.M. of 5 mice per group. *p < 0.05 vs. corresponding values at time 0; Two-way ANOVA for repeated measures + Fisher’s LSD; F(3,12) = 11.177 and F(4,39) = 9.982 for time and time x treatment, respectively. Paw print test in SCA1 mice with severe motor impairment and wild-type acutely treated with Ro0711401 (E). Data were quantified by calculating the coefficient of variation of 5 consecutive strides with the left paw of each mouse. Values are means ± S.E.M. of 9 mice. *p < 0.05 (One-Way ANOVA plus Fisher’s PLSD) vs. SCA1 mice before the treatment. Representative traces were carried out 5 min prior and 60 min after drug injection. Motor performance on the rotarod of mGlu1-deficient crv4 mice and wild-type mice 1 hour following s.c. injection of vehicle or Ro0711401 (F). Values are means + S.E.M. of 4 mice per group.
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Figure 3: Acute treatment with the mGlu1 receptor PAM, Ro0711401, improves motor performance in symptomatic SCA1 mice. Effect of Ro0711401 on the rotarod in symptomatic SCA1 mice with mild motor impairment (A); values are means ± S.E.M. of 4 mice per group. *p < 0.05 vs. corresponding values at time 0; Two-way ANOVA for repeated measures + Fisher’s LSD: F(3,21) = 7.621 and F(1,21) = 10.176 for time and treatment, respectively; and in wild-type littermates (B); data are means ± S.E.M. of 7 mice per group. Lack of effect of JNJ16259685 in SCA1 mice with mild motor impairment and wild-type (C), where data are means ± S.E.M. of 4 mice per group; *p < 0.05 vs. respective values at time 0. Two-way ANOVA for repeated measures + Fisher’s LSD; F(3,18) = 34.38 and F(1,18) = 7.24 for time and treatment, respectively. Effect of Ro0711401 in symptomatic SCA1 mice with severe motor impairment (D); values are means ± S.E.M. of 5 mice per group. *p < 0.05 vs. corresponding values at time 0; Two-way ANOVA for repeated measures + Fisher’s LSD; F(3,12) = 11.177 and F(4,39) = 9.982 for time and time x treatment, respectively. Paw print test in SCA1 mice with severe motor impairment and wild-type acutely treated with Ro0711401 (E). Data were quantified by calculating the coefficient of variation of 5 consecutive strides with the left paw of each mouse. Values are means ± S.E.M. of 9 mice. *p < 0.05 (One-Way ANOVA plus Fisher’s PLSD) vs. SCA1 mice before the treatment. Representative traces were carried out 5 min prior and 60 min after drug injection. Motor performance on the rotarod of mGlu1-deficient crv4 mice and wild-type mice 1 hour following s.c. injection of vehicle or Ro0711401 (F). Values are means + S.E.M. of 4 mice per group.

Mentions: Thirty-week old SCA1 mice showed a reduced motor performance on the rotarod, and signs of ataxia in the paw print test. However, the extent of motor impairment in these mice was variable, with some of them showing a mild motor impairment and other a severe impairment at the rotarod. Motor performance in SCA1 mice with mild impairment was slightly but significantly improved by a single systemic administration with the mGlu1 receptor PAM, Ro0711401 (10 mg/kg, s.c.) at all times from 30 to 90 min post-injection (Figure 3A). Injection of Ro0711401 had no effect on motor performance in wild-type littermates (Figure 3B). In contrast, single injection of the mGlu1 receptor negative allosteric modulator (NAM), JNJ16259685 (2.5 mg/kg, i.p.), markedly reduced motor performance both in wild-type and 30-week old SCA1 with mild motor impairment at 30 and 60 min post-injection (Figure 3C). In mice with severe impairment of motor performance (latency to fall < 100 sec on the rotarod), a single injection with Ro0711401 caused a large improvement of motor coordination, which was visible at 60 and 90 min post injection (Figure 3D,E). To exclude the possibility that Ro0711401 increased motor performance by an off-target effect, we tested the compound in mGlu1-deficient crv4 mice, which display severe ataxia [17]. As opposed to what observed in SCA1 mice, a single injection of Ro0711401 (10 mg/kg, s.c.) did not improve motor performance on the rotarod in crv4 mice (Figure 3F).


Pharmacological enhancement of mGlu1 metabotropic glutamate receptors causes a prolonged symptomatic benefit in a mouse model of spinocerebellar ataxia type 1.

Notartomaso S, Zappulla C, Biagioni F, Cannella M, Bucci D, Mascio G, Scarselli P, Fazio F, Weisz F, Lionetto L, Simmaco M, Gradini R, Battaglia G, Signore M, Puliti A, Nicoletti F - Mol Brain (2013)

Acute treatment with the mGlu1 receptor PAM, Ro0711401, improves motor performance in symptomatic SCA1 mice. Effect of Ro0711401 on the rotarod in symptomatic SCA1 mice with mild motor impairment (A); values are means ± S.E.M. of 4 mice per group. *p < 0.05 vs. corresponding values at time 0; Two-way ANOVA for repeated measures + Fisher’s LSD: F(3,21) = 7.621 and F(1,21) = 10.176 for time and treatment, respectively; and in wild-type littermates (B); data are means ± S.E.M. of 7 mice per group. Lack of effect of JNJ16259685 in SCA1 mice with mild motor impairment and wild-type (C), where data are means ± S.E.M. of 4 mice per group; *p < 0.05 vs. respective values at time 0. Two-way ANOVA for repeated measures + Fisher’s LSD; F(3,18) = 34.38 and F(1,18) = 7.24 for time and treatment, respectively. Effect of Ro0711401 in symptomatic SCA1 mice with severe motor impairment (D); values are means ± S.E.M. of 5 mice per group. *p < 0.05 vs. corresponding values at time 0; Two-way ANOVA for repeated measures + Fisher’s LSD; F(3,12) = 11.177 and F(4,39) = 9.982 for time and time x treatment, respectively. Paw print test in SCA1 mice with severe motor impairment and wild-type acutely treated with Ro0711401 (E). Data were quantified by calculating the coefficient of variation of 5 consecutive strides with the left paw of each mouse. Values are means ± S.E.M. of 9 mice. *p < 0.05 (One-Way ANOVA plus Fisher’s PLSD) vs. SCA1 mice before the treatment. Representative traces were carried out 5 min prior and 60 min after drug injection. Motor performance on the rotarod of mGlu1-deficient crv4 mice and wild-type mice 1 hour following s.c. injection of vehicle or Ro0711401 (F). Values are means + S.E.M. of 4 mice per group.
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Figure 3: Acute treatment with the mGlu1 receptor PAM, Ro0711401, improves motor performance in symptomatic SCA1 mice. Effect of Ro0711401 on the rotarod in symptomatic SCA1 mice with mild motor impairment (A); values are means ± S.E.M. of 4 mice per group. *p < 0.05 vs. corresponding values at time 0; Two-way ANOVA for repeated measures + Fisher’s LSD: F(3,21) = 7.621 and F(1,21) = 10.176 for time and treatment, respectively; and in wild-type littermates (B); data are means ± S.E.M. of 7 mice per group. Lack of effect of JNJ16259685 in SCA1 mice with mild motor impairment and wild-type (C), where data are means ± S.E.M. of 4 mice per group; *p < 0.05 vs. respective values at time 0. Two-way ANOVA for repeated measures + Fisher’s LSD; F(3,18) = 34.38 and F(1,18) = 7.24 for time and treatment, respectively. Effect of Ro0711401 in symptomatic SCA1 mice with severe motor impairment (D); values are means ± S.E.M. of 5 mice per group. *p < 0.05 vs. corresponding values at time 0; Two-way ANOVA for repeated measures + Fisher’s LSD; F(3,12) = 11.177 and F(4,39) = 9.982 for time and time x treatment, respectively. Paw print test in SCA1 mice with severe motor impairment and wild-type acutely treated with Ro0711401 (E). Data were quantified by calculating the coefficient of variation of 5 consecutive strides with the left paw of each mouse. Values are means ± S.E.M. of 9 mice. *p < 0.05 (One-Way ANOVA plus Fisher’s PLSD) vs. SCA1 mice before the treatment. Representative traces were carried out 5 min prior and 60 min after drug injection. Motor performance on the rotarod of mGlu1-deficient crv4 mice and wild-type mice 1 hour following s.c. injection of vehicle or Ro0711401 (F). Values are means + S.E.M. of 4 mice per group.
Mentions: Thirty-week old SCA1 mice showed a reduced motor performance on the rotarod, and signs of ataxia in the paw print test. However, the extent of motor impairment in these mice was variable, with some of them showing a mild motor impairment and other a severe impairment at the rotarod. Motor performance in SCA1 mice with mild impairment was slightly but significantly improved by a single systemic administration with the mGlu1 receptor PAM, Ro0711401 (10 mg/kg, s.c.) at all times from 30 to 90 min post-injection (Figure 3A). Injection of Ro0711401 had no effect on motor performance in wild-type littermates (Figure 3B). In contrast, single injection of the mGlu1 receptor negative allosteric modulator (NAM), JNJ16259685 (2.5 mg/kg, i.p.), markedly reduced motor performance both in wild-type and 30-week old SCA1 with mild motor impairment at 30 and 60 min post-injection (Figure 3C). In mice with severe impairment of motor performance (latency to fall < 100 sec on the rotarod), a single injection with Ro0711401 caused a large improvement of motor coordination, which was visible at 60 and 90 min post injection (Figure 3D,E). To exclude the possibility that Ro0711401 increased motor performance by an off-target effect, we tested the compound in mGlu1-deficient crv4 mice, which display severe ataxia [17]. As opposed to what observed in SCA1 mice, a single injection of Ro0711401 (10 mg/kg, s.c.) did not improve motor performance on the rotarod in crv4 mice (Figure 3F).

Bottom Line: Spinocerebellar ataxia type 1 (SCA1) is a genetic disorder characterized by severe ataxia associated with progressive loss of cerebellar Purkinje cells.A single injection of Ro0711401 improved motor symptoms for several days, and no tolerance developed to the drug.The prolonged symptomatic benefit caused by Ro0711401 outlasted the time of drug clearance from the cerebellum, and was associated with neuroadaptive changes in the cerebellum, such as a striking reduction of the ectopically expressed mGlu5 receptors in Purkinje cells, increases in levels of total and Ser880-phosphorylated GluA2 subunit of AMPA receptors, and changes in the length of spines in the distal dendrites of Purkinje cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: I,R,C,C,S, Neuromed, Pozzilli, Italy. ferdinandonicoletti@hotmail.com.

ABSTRACT

Background: Spinocerebellar ataxia type 1 (SCA1) is a genetic disorder characterized by severe ataxia associated with progressive loss of cerebellar Purkinje cells. The mGlu1 metabotropic glutamate receptor plays a key role in mechanisms of activity-dependent synaptic plasticity in the cerebellum, and its dysfunction is linked to the pathophysiology of motor symptoms associated with SCA1. We used SCA1 heterozygous transgenic mice (Q154/Q2) as a model for testing the hypothesis that drugs that enhance mGlu1 receptor function may be good candidates for the medical treatment of SCA1.

Results: Symptomatic 30-week old SCA1 mice showed reduced mGlu1 receptor mRNA and protein levels in the cerebellum. Interestingly, these mice also showed an intense expression of mGlu5 receptors in cerebellar Purkinje cells, which normally lack these receptors. Systemic treatment of SCA1 mice with the mGlu1 receptor positive allosteric modulator (PAM), Ro0711401 (10 mg/kg, s.c.), caused a prolonged improvement of motor performance on the rotarod and the paw-print tests. A single injection of Ro0711401 improved motor symptoms for several days, and no tolerance developed to the drug. In contrast, the mGlu5 receptor PAM, VU0360172 (10 mg/kg, s.c.), caused only a short-lasting improvement of motor symptoms, whereas the mGlu1 receptor antagonist, JNJ16259685 (2.5 mg/kg, i.p.), further impaired motor performance in SCA1 mice. The prolonged symptomatic benefit caused by Ro0711401 outlasted the time of drug clearance from the cerebellum, and was associated with neuroadaptive changes in the cerebellum, such as a striking reduction of the ectopically expressed mGlu5 receptors in Purkinje cells, increases in levels of total and Ser880-phosphorylated GluA2 subunit of AMPA receptors, and changes in the length of spines in the distal dendrites of Purkinje cells.

Conclusions: These data demonstrate that pharmacological enhancement of mGlu1 receptors causes a robust and sustained motor improvement in SCA1 mice, and lay the groundwork for the development of mGlu1 receptor PAMs as novel "cerebellum-specific", effective, and safe symptomatic drugs for the treatment of SCA1 in humans.

Show MeSH
Related in: MedlinePlus