Huntingtons disease (HD) involves marked early neurodegeneration in the striatum whereas the cerebellum is relatively spared despite the ubiquitous expression of full-length mutant huntingtin, implying that inherent tissue-specific differences determine susceptibility to the HD CAG mutation. To understand this tissue specificity, we compared early mutant huntingtin-induced gene expression changes in striatum to those in cerebellum in young Hdh CAG knock-in mice, prior to onset of evident pathological alterations. Endogenous levels of full-length mutant huntingtin caused qualitatively similar, but quantitatively different gene expression changes in the two brain regions. Importantly, the quantitatively different responses in striatum and cerebellum in mutant mice were well accounted for by the intrinsic molecular differences in gene expression between striatum and cerebellum in wild-type animals. Tissue-specific gene expression changes in response to the HD mutation, therefore, appear to reflect the different inherent capacities of these tissues to buffer qualitatively similar effects of mutant huntingtin. These findings highlight a role for intrinsic quantitative tissue differences in contributing to HD pathogenesis, and likely to other neurodegenerative disorders exhibiting tissue-specificity, thereby guiding the search for effective therapeutic interventions.
Differential effects of the Huntington's disease CAG mutation in striatum and cerebellum are quantitative not qualitative.
Specimen part
View SamplesHuntington's disease (HD) features a unique disease-initiating mechanism hypothesized to entail an impact of the CAG repeat encoded polyglutamine region on the full-length huntingtin protein, with dominant effects that are continuous with CAG size, in a simple gain of function. To evaluate these predictions, we generated a series of heterozygous Hdh CAG knock-in mouse embryonic stem (ES) cell lines, with 18, 48, 89, 109 CAGs, and found that a continuous analytic strategy efficiently identified, from genome-wide datasets, 73 genes and 172 pathways whose expression varied continuously with CAG length. The CAG-correlated genes were distinct from the set of 754 genes that distinguished huntingtin null ES cells from wild-type controls, and CAG-correlated pathways did not display a one-to-one correspondence with the 238 pathways altered in huntingtin null ES cells. Rather, the genes that varied with CAG size were either members of the same pathways as altered genes in huntingtin null cells or were members of unique pathways related to these pathways. These findings falsified a gain of function/loss of function proposal but were consistent with the simple gain of novel function mechanism hypothesis. The dominant CAG correlated gene expression changes conformed to the genetic features of the HD initiating mechanism and were system-wide and inter-related with pathways perturbed by lack of full-length huntingtin function, urging system-wide approaches for the discovery and validation of potential modulating factors, in the search for effective HD therapeutics.
HD CAG-correlated gene expression changes support a simple dominant gain of function.
Cell line
View SamplesIn Huntingtons disease (HD), an expanded CAG repeat produces characteristic striatal neurodegeneration. Interestingly, the HD CAG repeat, whose length determines age at onset, undergoes tissue-specific somatic instability, predominant in the striatum, suggesting that tissue-specific CAG length changes could modify the disease process. Therefore, understanding the mechanisms underlying the tissue specificity of somatic instability may provide novel routes to therapies. However progress in this area has been hampered by the lack of sensitive high-throughput instability quantification methods and global approaches to identify the underlying factors.
A novel approach to investigate tissue-specific trinucleotide repeat instability.
Specimen part
View SamplesIn Huntingtons disease (HD), an expanded CAG repeat produces characteristic striatal neurodegeneration. Interestingly, the HD CAG repeat, whose length determines age at onset, undergoes tissue-specific somatic instability, predominant in the striatum, suggesting that tissue-specific CAG length changes could modify the disease process. Therefore, understanding the mechanisms underlying the tissue specificity of somatic instability may provide novel routes to therapies. However progress in this area has been hampered by the lack of sensitive high-throughput instability quantification methods and global approaches to identify the underlying factors.
A novel approach to investigate tissue-specific trinucleotide repeat instability.
Age, Specimen part
View SamplesWe demonstrate that expression of key markers of keratinocyte differentiation is suppressed by exposure to sodium arsenite. Folate deficiency exacerbates this effect. In addition, cancer-related cell movement genes, and growth and proliferation genes are altered. Several redox-sensitive transcription factors are implicated in mediating these gene expression changes due to arsenic treatment and folate deficiency.
Folate deficiency enhances arsenic effects on expression of genes involved in epidermal differentiation in transgenic K6/ODC mouse skin.
No sample metadata fields
View SamplesDuring development of the mammalian central nervous system (CNS), neurons and glial cells (astrocytes and oligodendrocytes) are generated from common neural precursor cells (NPCs). However, neurogenesis precedes gliogenesis, which normally commences at later stages of fetal telencephalic development. Astrocyte differentiation of mouse NPCs at embryonic day (E) 14.5 (relatively late gestation) is induced by activation of the transcription factor STAT3, whereas at E11.5 (mid-gestation) NPCs do not differentiate into astrocytes even when stimulated by STAT3-activating cytokines such as leukemia inhibitory factor (LIF). This can be explained in part by the fact that astrocyte-specific gene promoters are highly methylated in NPCs at E11.5, but other mechanisms are also likely to play a role. We therefore sought to identify genes involved in the inhibition of astrocyte differentiation of NPCs at midgestation. We first examined gene expression profiles in E11.5 and E14.5 NPCs, using Affymetrix GeneChip analysis, applying the Percellome method to normalize gene expression level. We then conducted in situ hybridization analysis for selected genes found to be highly expressed in NPCs at midgestation. Among these genes, we found that N-myc and high mobility group AT-hook 2 (Hmga2) were highly expressed in the E11.5 but not the E14.5 ventricular zone of mouse brain, where NPCs reside. Transduction of N-myc and Hmga2 by retroviruses into E14.5 NPCs, which normally differentiate into astrocytes in response to LIF, resulted in suppression of astrocyte differentiation. However, sustained expression of N-myc and Hmga2 in E11.5 NPCs failed to maintain the hypermethylated status of an astrocyte-specific gene promoter. Taken together, our data suggest that astrocyte differentiation of NPCs is regulated not only by DNA methylation but also by genes whose expression is controlled spatio-temporally during brain development.
Identification of genes that restrict astrocyte differentiation of midgestational neural precursor cells.
No sample metadata fields
View Samplescompare wild type and Batf-/- B cells activated for 0 1 or 2 days in vitro.
The transcription factor BATF controls the global regulators of class-switch recombination in both B cells and T cells.
Specimen part
View SamplesAnalysis of differentiating LSD1-KD C2C12 myoblasts. We found LSD1 is an important regulator of oxidative phenotypes in skeletal muscle cells.
LSD1 mediates metabolic reprogramming by glucocorticoids during myogenic differentiation.
Specimen part, Cell line
View SamplesMouse lung CD11c+ dendritic cells are composed of 2 major DC subsets, the CD103+CD11b-low/intermediate DC (CD103+ DC) and the CD11b-highCD103- DC (CD11b-high DC). These 2 subsets are functionally distinct. Comparison of their functions showed CD103+ DC
Peripheral CD103+ dendritic cells form a unified subset developmentally related to CD8alpha+ conventional dendritic cells.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Protein kinase c-β-dependent activation of NF-κB in stromal cells is indispensable for the survival of chronic lymphocytic leukemia B cells in vivo.
Specimen part, Cell line
View Samples