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MeCP2 regulates the synaptic expression of a Dysbindin-BLOC-1 network component in mouse brain and human induced pluripotent stem cell-derived neurons.

Larimore J, Ryder PV, Kim KY, Ambrose LA, Chapleau C, Calfa G, Gross C, Bassell GJ, Pozzo-Miller L, Smith Y, Talbot K, Park IH, Faundez V - PLoS ONE (2013)

Bottom Line: In addition, we confirmed results by performing immunohistochemistry of normal human hippocampus and quantitative qRT-PCR of human inducible pluripotent stem cells (iPSCs)-derived human neurons from Rett syndrome patients.Pallidin immunoreactivity decreased concomitantly with reduced BDNF content in the hippocampus of Mecp2 mice.Our results demonstrate that the ASD-related gene Mecp2 regulates the expression of components belonging to the dysbindin interactome and these molecular differences may contribute to synaptic phenotypes that characterize Mecp2 deficiencies and ASD.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Agnes Scott College, Decatur, Georgia, USA.

ABSTRACT
Clinical, epidemiological, and genetic evidence suggest overlapping pathogenic mechanisms between autism spectrum disorder (ASD) and schizophrenia. We tested this hypothesis by asking if mutations in the ASD gene MECP2 which cause Rett syndrome affect the expression of genes encoding the schizophrenia risk factor dysbindin, a subunit of the biogenesis of lysosome-related organelles complex-1 (BLOC-1), and associated interacting proteins. We measured mRNA and protein levels of key components of a dysbindin interaction network by, quantitative real time PCR and quantitative immunohistochemistry in hippocampal samples of wild-type and Mecp2 mutant mice. In addition, we confirmed results by performing immunohistochemistry of normal human hippocampus and quantitative qRT-PCR of human inducible pluripotent stem cells (iPSCs)-derived human neurons from Rett syndrome patients. We defined the distribution of the BLOC-1 subunit pallidin in human and mouse hippocampus and contrasted this distribution with that of symptomatic Mecp2 mutant mice. Neurons from mutant mice and Rett syndrome patients displayed selectively reduced levels of pallidin transcript. Pallidin immunoreactivity decreased in the hippocampus of symptomatic Mecp2 mutant mice, a feature most prominent at asymmetric synapses as determined by immunoelectron microcopy. Pallidin immunoreactivity decreased concomitantly with reduced BDNF content in the hippocampus of Mecp2 mice. Similarly, BDNF content was reduced in the hippocampus of BLOC-1 deficient mice suggesting that genetic defects in BLOC-1 are upstream of the BDNF phenotype in Mecp2 deficient mice. Our results demonstrate that the ASD-related gene Mecp2 regulates the expression of components belonging to the dysbindin interactome and these molecular differences may contribute to synaptic phenotypes that characterize Mecp2 deficiencies and ASD.

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Quantitative Real Time PCR Determination of BLOC-1 Subunit Transcripts.BLOC-1 subunit transcripts from symptomatic adult (A) and P7 (B) mice hippocampi and cortices were analyzed by qRT-PCR. Box plot depicts relative mRNA content for wild type (Mecp2+/y, Blue) and Mecp2 mutant tissue (Mecp2tm1.1Jae/y, Red). P values were obtained by Mann-Whitney U test. Number of animals tested is presented in Table 1.
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pone-0065069-g002: Quantitative Real Time PCR Determination of BLOC-1 Subunit Transcripts.BLOC-1 subunit transcripts from symptomatic adult (A) and P7 (B) mice hippocampi and cortices were analyzed by qRT-PCR. Box plot depicts relative mRNA content for wild type (Mecp2+/y, Blue) and Mecp2 mutant tissue (Mecp2tm1.1Jae/y, Red). P values were obtained by Mann-Whitney U test. Number of animals tested is presented in Table 1.

Mentions: Numbers show IPSCs or animals analyzed in Figure 2, 3, 7 and correspond to Wild type hippocampus: Mecp2 or BLOC-1 mutant hippocampus: Wild type cortex: Mecp2 mutant cortex. Each animal qRT-PCR determination was performed at least in duplicate.


MeCP2 regulates the synaptic expression of a Dysbindin-BLOC-1 network component in mouse brain and human induced pluripotent stem cell-derived neurons.

Larimore J, Ryder PV, Kim KY, Ambrose LA, Chapleau C, Calfa G, Gross C, Bassell GJ, Pozzo-Miller L, Smith Y, Talbot K, Park IH, Faundez V - PLoS ONE (2013)

Quantitative Real Time PCR Determination of BLOC-1 Subunit Transcripts.BLOC-1 subunit transcripts from symptomatic adult (A) and P7 (B) mice hippocampi and cortices were analyzed by qRT-PCR. Box plot depicts relative mRNA content for wild type (Mecp2+/y, Blue) and Mecp2 mutant tissue (Mecp2tm1.1Jae/y, Red). P values were obtained by Mann-Whitney U test. Number of animals tested is presented in Table 1.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3672180&req=5

pone-0065069-g002: Quantitative Real Time PCR Determination of BLOC-1 Subunit Transcripts.BLOC-1 subunit transcripts from symptomatic adult (A) and P7 (B) mice hippocampi and cortices were analyzed by qRT-PCR. Box plot depicts relative mRNA content for wild type (Mecp2+/y, Blue) and Mecp2 mutant tissue (Mecp2tm1.1Jae/y, Red). P values were obtained by Mann-Whitney U test. Number of animals tested is presented in Table 1.
Mentions: Numbers show IPSCs or animals analyzed in Figure 2, 3, 7 and correspond to Wild type hippocampus: Mecp2 or BLOC-1 mutant hippocampus: Wild type cortex: Mecp2 mutant cortex. Each animal qRT-PCR determination was performed at least in duplicate.

Bottom Line: In addition, we confirmed results by performing immunohistochemistry of normal human hippocampus and quantitative qRT-PCR of human inducible pluripotent stem cells (iPSCs)-derived human neurons from Rett syndrome patients.Pallidin immunoreactivity decreased concomitantly with reduced BDNF content in the hippocampus of Mecp2 mice.Our results demonstrate that the ASD-related gene Mecp2 regulates the expression of components belonging to the dysbindin interactome and these molecular differences may contribute to synaptic phenotypes that characterize Mecp2 deficiencies and ASD.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Agnes Scott College, Decatur, Georgia, USA.

ABSTRACT
Clinical, epidemiological, and genetic evidence suggest overlapping pathogenic mechanisms between autism spectrum disorder (ASD) and schizophrenia. We tested this hypothesis by asking if mutations in the ASD gene MECP2 which cause Rett syndrome affect the expression of genes encoding the schizophrenia risk factor dysbindin, a subunit of the biogenesis of lysosome-related organelles complex-1 (BLOC-1), and associated interacting proteins. We measured mRNA and protein levels of key components of a dysbindin interaction network by, quantitative real time PCR and quantitative immunohistochemistry in hippocampal samples of wild-type and Mecp2 mutant mice. In addition, we confirmed results by performing immunohistochemistry of normal human hippocampus and quantitative qRT-PCR of human inducible pluripotent stem cells (iPSCs)-derived human neurons from Rett syndrome patients. We defined the distribution of the BLOC-1 subunit pallidin in human and mouse hippocampus and contrasted this distribution with that of symptomatic Mecp2 mutant mice. Neurons from mutant mice and Rett syndrome patients displayed selectively reduced levels of pallidin transcript. Pallidin immunoreactivity decreased in the hippocampus of symptomatic Mecp2 mutant mice, a feature most prominent at asymmetric synapses as determined by immunoelectron microcopy. Pallidin immunoreactivity decreased concomitantly with reduced BDNF content in the hippocampus of Mecp2 mice. Similarly, BDNF content was reduced in the hippocampus of BLOC-1 deficient mice suggesting that genetic defects in BLOC-1 are upstream of the BDNF phenotype in Mecp2 deficient mice. Our results demonstrate that the ASD-related gene Mecp2 regulates the expression of components belonging to the dysbindin interactome and these molecular differences may contribute to synaptic phenotypes that characterize Mecp2 deficiencies and ASD.

Show MeSH
Related in: MedlinePlus