Limits...
Beneficial effects of estrogen in a mouse model of cerebrovascular insufficiency.

Kitamura N, Araya R, Kudoh M, Kishida H, Kimura T, Murayama M, Takashima A, Sakamaki Y, Hashikawa T, Ito S, Ohtsuki S, Terasaki T, Wess J, Yamada M - PLoS ONE (2009)

Bottom Line: Agonists of ERalpha, ERbeta, and GPR30 promoted ERK activation in this cell line.This phenotype was reversed by E2 treatment, similar to the observed deficits in dendrite morphology and the number of synapses.E2 may offer new therapeutic perspectives for the treatment of cerebrovascular insufficiency related memory dysfunction.

View Article: PubMed Central - PubMed

Affiliation: Yamada Research Unit, RIKEN Brain Science Institute, Saitama, Japan.

ABSTRACT

Background: The M(5) muscarinic acetylcholine receptor is known to play a crucial role in mediating acetylcholine dependent dilation of cerebral blood vessels. Previously, we reported that male M(5) muscarinic acetylcholine knockout mice (M5R(-/-) mice) suffer from a constitutive constriction of cerebral arteries, reduced cerebral blood flow, dendritic atrophy, and short-term memory loss, without necrosis and/or inflammation in the brain.

Methodology/principal findings: We employed the Magnetic Resonance Angiography to study the area of the basilar artery in male and female M5R(-/-) mice. Here we show that female M5R(-/-) mice did not show the reduction in vascular area observed in male M5R(-/-) mice. However, ovariectomized female M5R(-/-) mice displayed phenotypic changes similar to male M5R(-/-) mice, strongly suggesting that estrogen plays a key role in the observed gender differences. We found that 17beta-estradiol (E2) induced nitric oxide release and ERK activation in a conditional immortalized mouse brain cerebrovascular endothelial cell line. Agonists of ERalpha, ERbeta, and GPR30 promoted ERK activation in this cell line. Moreover, in vivo magnetic resonance imaging studies showed that the cross section of the basilar artery was restored to normal in male M5R(-/-) mice treated with E2. Treatment with E2 also improved the performance of male M5R(-/-) mice in a cognitive test and reduced the atrophy of neural dendrites in the cerebral cortex and hippocampus. M5R(-/-) mice also showed astrocyte swelling in cortex and hippocampus using the three-dimensional reconstruction of electron microscope images. This phenotype was reversed by E2 treatment, similar to the observed deficits in dendrite morphology and the number of synapses.

Conclusions/significance: Our findings indicate that M5R(-/-) mice represent an excellent novel model system to study the beneficial effects of estrogen on cerebrovascular function and cognition. E2 may offer new therapeutic perspectives for the treatment of cerebrovascular insufficiency related memory dysfunction.

Show MeSH

Related in: MedlinePlus

E2 restores normal morphology in cortical and hippocampal pyramidal neurons from male M5R−/− mice.(A) Morphologic changes of cortical pyramidal neurons (layer V) from male M5R−/− mice without or after chronic E2 treatment (3 weeks). Golgi staining revealed that cortical pyramidal neurons from male M5R−/− mice showed clear signs of atrophy of the basal-dendritic tree and apical dendrites. E2 treated male M5R−/− mice showed a similar morphology of spines in the basal-dendritic tree and apical dendrites as M5R+/+ control mice. (B) Number of spines per 10 µm length of dendritic segment of cortical pyramidal neurons (layer V) from male M5R−/− and M5R+/+ mice, and E2 treated male M5R−/− and M5R+/+ mice. N = 40 dendritic segments from 5 animals per group. (C) Number of spines per 10 µm length of dendritic segment of CA3 hippocampal pyramidal neurons from male M5R−/− and M5R+/+ mice, and E2 treated male M5R−/− and M5R+/+ mice. Hippocampal neurons from male M5R−/− mice exhibited a significantly reduced number of dendritic spines. E2 administration also restored the number of dendritic spines in the CA3 hippocampus. N = 20 dendritic segments from 5 animals per group. Values are means±SEM. **p<0.001. (D) The number of synapses per 102 µm was counted in the CA3 hippocampus by analyzing electron microscope images. A total of 100–110 sections of 70 nm electron microscope images were counted for each sample. Values are means±SEM. **p<0.001. (E) Performance of male M5R+/+ and M5R−/− mice prior to and after chronic E2 treatment in a Y-maze spatial-memory test. Chronic E2 tablet (0.1 mg / 21 days release) treatment completely rescues cerebrovascular and cognitive deficits in male M5R−/− mice. All studies were carried out with 3 month-old male M5R+/+ (n = 16) and M5R−/− (n = 14) mice. Values are means±SEM. *p<0.05, **p<0.001.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2664330&req=5

pone-0005159-g007: E2 restores normal morphology in cortical and hippocampal pyramidal neurons from male M5R−/− mice.(A) Morphologic changes of cortical pyramidal neurons (layer V) from male M5R−/− mice without or after chronic E2 treatment (3 weeks). Golgi staining revealed that cortical pyramidal neurons from male M5R−/− mice showed clear signs of atrophy of the basal-dendritic tree and apical dendrites. E2 treated male M5R−/− mice showed a similar morphology of spines in the basal-dendritic tree and apical dendrites as M5R+/+ control mice. (B) Number of spines per 10 µm length of dendritic segment of cortical pyramidal neurons (layer V) from male M5R−/− and M5R+/+ mice, and E2 treated male M5R−/− and M5R+/+ mice. N = 40 dendritic segments from 5 animals per group. (C) Number of spines per 10 µm length of dendritic segment of CA3 hippocampal pyramidal neurons from male M5R−/− and M5R+/+ mice, and E2 treated male M5R−/− and M5R+/+ mice. Hippocampal neurons from male M5R−/− mice exhibited a significantly reduced number of dendritic spines. E2 administration also restored the number of dendritic spines in the CA3 hippocampus. N = 20 dendritic segments from 5 animals per group. Values are means±SEM. **p<0.001. (D) The number of synapses per 102 µm was counted in the CA3 hippocampus by analyzing electron microscope images. A total of 100–110 sections of 70 nm electron microscope images were counted for each sample. Values are means±SEM. **p<0.001. (E) Performance of male M5R+/+ and M5R−/− mice prior to and after chronic E2 treatment in a Y-maze spatial-memory test. Chronic E2 tablet (0.1 mg / 21 days release) treatment completely rescues cerebrovascular and cognitive deficits in male M5R−/− mice. All studies were carried out with 3 month-old male M5R+/+ (n = 16) and M5R−/− (n = 14) mice. Values are means±SEM. *p<0.05, **p<0.001.

Mentions: We examined the effect of chronic (3 weeks) E2 treatment on astrocyte morphological changes. As expected, non-treated male M5R−/− mice (4 months old) showed a significant reduction in spine number in cortical (Figure 7A,B) and CA3 hippocampal pyramidal neurons (Figure 7C), and synapse number in CA3 hippocampal pyramidal neurons (Figure 7D). However, after 3 weeks of E2 treatment, these morphological deficits were greatly ameliorated (Figure 7A–D).


Beneficial effects of estrogen in a mouse model of cerebrovascular insufficiency.

Kitamura N, Araya R, Kudoh M, Kishida H, Kimura T, Murayama M, Takashima A, Sakamaki Y, Hashikawa T, Ito S, Ohtsuki S, Terasaki T, Wess J, Yamada M - PLoS ONE (2009)

E2 restores normal morphology in cortical and hippocampal pyramidal neurons from male M5R−/− mice.(A) Morphologic changes of cortical pyramidal neurons (layer V) from male M5R−/− mice without or after chronic E2 treatment (3 weeks). Golgi staining revealed that cortical pyramidal neurons from male M5R−/− mice showed clear signs of atrophy of the basal-dendritic tree and apical dendrites. E2 treated male M5R−/− mice showed a similar morphology of spines in the basal-dendritic tree and apical dendrites as M5R+/+ control mice. (B) Number of spines per 10 µm length of dendritic segment of cortical pyramidal neurons (layer V) from male M5R−/− and M5R+/+ mice, and E2 treated male M5R−/− and M5R+/+ mice. N = 40 dendritic segments from 5 animals per group. (C) Number of spines per 10 µm length of dendritic segment of CA3 hippocampal pyramidal neurons from male M5R−/− and M5R+/+ mice, and E2 treated male M5R−/− and M5R+/+ mice. Hippocampal neurons from male M5R−/− mice exhibited a significantly reduced number of dendritic spines. E2 administration also restored the number of dendritic spines in the CA3 hippocampus. N = 20 dendritic segments from 5 animals per group. Values are means±SEM. **p<0.001. (D) The number of synapses per 102 µm was counted in the CA3 hippocampus by analyzing electron microscope images. A total of 100–110 sections of 70 nm electron microscope images were counted for each sample. Values are means±SEM. **p<0.001. (E) Performance of male M5R+/+ and M5R−/− mice prior to and after chronic E2 treatment in a Y-maze spatial-memory test. Chronic E2 tablet (0.1 mg / 21 days release) treatment completely rescues cerebrovascular and cognitive deficits in male M5R−/− mice. All studies were carried out with 3 month-old male M5R+/+ (n = 16) and M5R−/− (n = 14) mice. Values are means±SEM. *p<0.05, **p<0.001.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2664330&req=5

pone-0005159-g007: E2 restores normal morphology in cortical and hippocampal pyramidal neurons from male M5R−/− mice.(A) Morphologic changes of cortical pyramidal neurons (layer V) from male M5R−/− mice without or after chronic E2 treatment (3 weeks). Golgi staining revealed that cortical pyramidal neurons from male M5R−/− mice showed clear signs of atrophy of the basal-dendritic tree and apical dendrites. E2 treated male M5R−/− mice showed a similar morphology of spines in the basal-dendritic tree and apical dendrites as M5R+/+ control mice. (B) Number of spines per 10 µm length of dendritic segment of cortical pyramidal neurons (layer V) from male M5R−/− and M5R+/+ mice, and E2 treated male M5R−/− and M5R+/+ mice. N = 40 dendritic segments from 5 animals per group. (C) Number of spines per 10 µm length of dendritic segment of CA3 hippocampal pyramidal neurons from male M5R−/− and M5R+/+ mice, and E2 treated male M5R−/− and M5R+/+ mice. Hippocampal neurons from male M5R−/− mice exhibited a significantly reduced number of dendritic spines. E2 administration also restored the number of dendritic spines in the CA3 hippocampus. N = 20 dendritic segments from 5 animals per group. Values are means±SEM. **p<0.001. (D) The number of synapses per 102 µm was counted in the CA3 hippocampus by analyzing electron microscope images. A total of 100–110 sections of 70 nm electron microscope images were counted for each sample. Values are means±SEM. **p<0.001. (E) Performance of male M5R+/+ and M5R−/− mice prior to and after chronic E2 treatment in a Y-maze spatial-memory test. Chronic E2 tablet (0.1 mg / 21 days release) treatment completely rescues cerebrovascular and cognitive deficits in male M5R−/− mice. All studies were carried out with 3 month-old male M5R+/+ (n = 16) and M5R−/− (n = 14) mice. Values are means±SEM. *p<0.05, **p<0.001.
Mentions: We examined the effect of chronic (3 weeks) E2 treatment on astrocyte morphological changes. As expected, non-treated male M5R−/− mice (4 months old) showed a significant reduction in spine number in cortical (Figure 7A,B) and CA3 hippocampal pyramidal neurons (Figure 7C), and synapse number in CA3 hippocampal pyramidal neurons (Figure 7D). However, after 3 weeks of E2 treatment, these morphological deficits were greatly ameliorated (Figure 7A–D).

Bottom Line: Agonists of ERalpha, ERbeta, and GPR30 promoted ERK activation in this cell line.This phenotype was reversed by E2 treatment, similar to the observed deficits in dendrite morphology and the number of synapses.E2 may offer new therapeutic perspectives for the treatment of cerebrovascular insufficiency related memory dysfunction.

View Article: PubMed Central - PubMed

Affiliation: Yamada Research Unit, RIKEN Brain Science Institute, Saitama, Japan.

ABSTRACT

Background: The M(5) muscarinic acetylcholine receptor is known to play a crucial role in mediating acetylcholine dependent dilation of cerebral blood vessels. Previously, we reported that male M(5) muscarinic acetylcholine knockout mice (M5R(-/-) mice) suffer from a constitutive constriction of cerebral arteries, reduced cerebral blood flow, dendritic atrophy, and short-term memory loss, without necrosis and/or inflammation in the brain.

Methodology/principal findings: We employed the Magnetic Resonance Angiography to study the area of the basilar artery in male and female M5R(-/-) mice. Here we show that female M5R(-/-) mice did not show the reduction in vascular area observed in male M5R(-/-) mice. However, ovariectomized female M5R(-/-) mice displayed phenotypic changes similar to male M5R(-/-) mice, strongly suggesting that estrogen plays a key role in the observed gender differences. We found that 17beta-estradiol (E2) induced nitric oxide release and ERK activation in a conditional immortalized mouse brain cerebrovascular endothelial cell line. Agonists of ERalpha, ERbeta, and GPR30 promoted ERK activation in this cell line. Moreover, in vivo magnetic resonance imaging studies showed that the cross section of the basilar artery was restored to normal in male M5R(-/-) mice treated with E2. Treatment with E2 also improved the performance of male M5R(-/-) mice in a cognitive test and reduced the atrophy of neural dendrites in the cerebral cortex and hippocampus. M5R(-/-) mice also showed astrocyte swelling in cortex and hippocampus using the three-dimensional reconstruction of electron microscope images. This phenotype was reversed by E2 treatment, similar to the observed deficits in dendrite morphology and the number of synapses.

Conclusions/significance: Our findings indicate that M5R(-/-) mice represent an excellent novel model system to study the beneficial effects of estrogen on cerebrovascular function and cognition. E2 may offer new therapeutic perspectives for the treatment of cerebrovascular insufficiency related memory dysfunction.

Show MeSH
Related in: MedlinePlus