Recent microarray studies in the hippocampus of rodents or Alzheimers disease (AD) subjects have identified a substantial number of cellular pathways/processes correlated with aging and cognitive decline. However, the temporal relationships among these expression changes or with cognitive impairment have not been studied in depth. Here, using Affymetrix microarrays, immunohistochemistry and Morris water maze cognitive testing across 5 age groups of male F344 rats (n=9-15/group, one microarray per animal), we systematically analyzed the temporal sequence and cellular localization of aging changes in expression. These were correlated with performance scores on the hippocampus-dependent Morris Water Maze task. Significant microarray results were sorted in to Early, Intermediate, Midlife, and Late patterns of expression, and functionally categorized (Early- downregulated neural development, lipid synthesis and energy-utilization; upregulated ribosomal synthesis, growth, stress/inflammatory, lysosome and protein/lipid degradation. Intermediate- increased defense/inflammatory activation and decreased transporter activity; Midlife- downregulated energy-dependent signaling and neurite growth, upregulated astroglial activation, Ca2+-binding, cholesterol/lipid trafficking, myelinogenic processes and additional lysosome/inflammation; Late- further recruitment of genes in already-altered pathways). Immunohistochemistry revealed a primarily astrocytic localization of the processes upregulated in midlife, as well as increased density of myelin proteins. Evidence of cognitive impairment first appeared in the 12-month-old group (midlife) and was increased further in the 23-month-old group, exhibiting the highest correlations with some upregulated genes related to cholesterol transport (e.g., Apoe, Abca2), protein management and ion binding. Some upregulated genes for inflammation (Il6st) and myelinogenesis (Pmp22) also correlated with impairment. Together, the data are consistent with a novel sequential cascade model of brain aging in which metabolic alterations early in maturity are followed by inflammation and midlife activation of an astrocyte-centered cholesterol trafficking pathway that stimulates oligodendrocyte remyelination programs. Importantly, this cholesterol trafficking pathway also may compete for astroglial bioenergetic support of neurons, in turn, leading to downregulation of energy-dependent pathways needed to sustain cognitive functions.
Hippocampal and cognitive aging across the lifespan: a bioenergetic shift precedes and increased cholesterol trafficking parallels memory impairment.
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View SamplesHippocampal overexpression of FK506-binding protein 12.6/1b (FKBP1b), a negative regulator of ryanodine receptor Ca2+ release, reverses aging-induced memory impairment and neuronal Ca2+ dysregulation. Here, we test the hypothesis that FKBP1b also can protect downstream transcriptional networks from aging-induced dysregulation. We gave hippocampal microinjections of FKBP1b-expressing viral vector to male rats at either 13-months-of-age (long-term) or 19-months-of-age (short-term) and tested memory performance in the Morris water maze at 21-months-of-age. Aged rats treated short- or long-term with FKBP1b substantially outperformed age-matched vector controls and performed similarly to each other and young controls. Transcriptional profiling in the same animals identified 2342 genes whose hippocampal expression was up-/down-regulated in aged controls vs. young controls (the aging effect). Of these aging-dependent genes, 876 (37%) also showed altered expression in aged FKBP1b-treated rats compared to aged controls, with FKBP1b restoring expression of essentially all such genes (872/876, 99.5%) in the direction opposite the aging effect and closer to levels in young controls. This inverse relationship between the aging and FKBP1b effects suggests that the aging effects arise from FKBP1b deficiency. Functional category analysis revealed that genes downregulated with aging and restored by FKBP1b associated predominantly with diverse brain structure categories, including cytoskeleton, membrane channels and extracellular region. Conversely, genes upregulated with aging but not restored by FKBP1b associated primarily with glial-neuroinflammatory, ribosomal and lysosomal categories. Immunohistochemistry confirmed aging-induced rarefaction, and FKBP1b-mediated restoration, of neuronal microtubular structure. Thus, a previously-unrecognized genomic network modulating diverse brain structural processes is dysregulated by aging and restored by FKBP1b overexpression.
FK506-Binding Protein 12.6/1b, a Negative Regulator of [Ca<sup>2+</sup>], Rescues Memory and Restores Genomic Regulation in the Hippocampus of Aging Rats.
Sex, Specimen part, Treatment
View SamplesAlthough glucocorticoids (GCs) are known to exert numerous effects in the hippocampus, their chronic regulatory functions remain poorly understood. Moreover, evidence is inconsistent regarding the longstanding hypothesis that chronic GC exposure promotes brain aging/Alzheimer's disease. Here, we adrenalectomized male F344 rats at 15-months-of-age, maintained them for 3 months with implanted corticosterone (CORT) pellets producing low or intermediate (glucocorticoid-receptor (GR)-activating) blood levels of CORT, and performed microarray/pathway analyses in hippocampal CA1. We defined the chronic GC-dependent transcriptome as 393 genes that exhibited differential expression between Intermediate- and Low-CORT groups. Short-term CORT (4 days) did not recapitulate this transcriptome. Functional processes/pathways overrepresented by chronic CORT-upregulated genes included learning/plasticity, differentiation, glucose metabolism and cholesterol biosynthesis, whereas processes overrepresented by CORT-downregulated genes included inflammatory/immune/glial responses and extracellular structure. These profiles indicate that GCs chronically activate neuronal/metabolic processes while coordinately repressing a glial axis of reactivity/inflammation. We then compared the GC-transcriptome with a previously-defined hippocampal aging transcriptome, revealing a high proportion of common genes. Although CORT and aging moved expression of some common genes in the same-direction, the majority were shifted in opposite directions by CORT and aging (e.g., glial inflammatory genes downregulated by CORT are upregulated with aging). These results contradict the hypothesis that GCs simply promote brain aging, and also suggest that the opposite-direction shifts during aging reflect resistance to CORT regulation. Therefore, we propose a new model in which aging-related GC resistance develops in some target pathways while GC overstimulation develops in others, together generating much of the brain aging phenotype.
Glucocorticoid-dependent hippocampal transcriptome in male rats: pathway-specific alterations with aging.
Sex, Age, Specimen part
View SamplesAlthough immediate early genes (IEGs) such as Bdnf, Arc and Egr1, have been implicated in plasticity, the larger pathways related to memory and memory disorders are not well understood. Here, we combined statistical Affymetrix microarray and behavioral analyses to identify key genes and pathways associated with aging-related cognitive impairment. Aged rats were separated into cognitively unimpaired (AU) or impaired (AI) groups, based on their Morris water maze performance relative to young-adult (Y) animals. Hippocampal gene expression was assessed in Y, AU and AI on the fifth (last) day of maze training or 21 days posttraining, and in non-trained aged and young animals (eight groups, overall n = 78, one chip/animal). ANOVA, linear contrasts, and overrepresentation analyses identified genes and pathways that differed from Y generally with aging (in both AU and AI) or selectively with cognitive status (only in AI or AU). Plasticity pathways, including insulin/cAMP/IEG signaling, and glycogenolytic and lipogenic pathways, were selectively downregulated (5 days) in AI, whereas Notch2 (regulating oligodendrocyte differentiation) and myelination pathways were upregulated (particularly at 21 days). Downregulation with general aging occurred in signal transduction and axonal growth/transport pathways, whereas upegulation occurred in immune/inflammatory, lipid metabolism/transport (e.g., Lxr-Srebf1), and lysosomal pathways. In AU, receptor/signal transduction genes were selectively upregulated, suggesting possible compensatory mechanisms. Immunohistochemistry confirmed and extended results to the protein level. Thus, this study identified novel cognition-linked processes, suggesting a new model in which energy-intensive, plasticity/lipogenic processes and energy-generating pathways necessary for learning are coordinately downregulated during training, while myelinogenic programs that impair cognition are concurrently activated.
Hippocampal expression analyses reveal selective association of immediate-early, neuroenergetic, and myelinogenic pathways with cognitive impairment in aged rats.
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View SamplesCutaneous CD30+ lymphoproliferative disorder (CD30+LPDs), including lymphomatoid papulosis (LyP) and primary cutaneous anaplastic large-cell lymphoma (PCALCL), comprises the second most common group of cutaneous T cell lymphoma. Previously, we reported that special AT-rich sequence-binding protein1 (SATB1), a thymocyte specific chromatin organizer, was over-expressed and promoted malignant T-cell proliferation in a portion of CD30+LPDs, whereas other CD30+LPDs didn't express SATB1 at all. To elucidate the underlying molecular events in CD30+LPDs with differential SATB1 expression, we subjected 4 SATB1+ and 3 SATB1- CD30+LPDs skin biopsies to second-generation RNA-sequencing (RNA-seq). These data provide a significant resource for studies of CD30+LPDs. Overall design: 200ng total RNA samples were extracted and purified from 7 CD30+LPDs skin lesions (4 SATB1+, 3 SATB1-) to establish RNA library. Then the library was qualified through Agilent 2100 bioanalyzer instrument (Agilent Technologies, Santa Clara, CA) and Quantitative real-time polymerase chain reaction. The qualified library was sequenced on an Illumina HiSeqTM 2000 platform using paired-end reads. 10G raw data for each sample were obtained. The reads were aligned to the hg19 genome with SOAPaligner/SOAP2. Gene expression levels were calculated by reads per kilobase transcriptome per million mapped reads(RPKM)method.
SATB1 Defines a Subtype of Cutaneous CD30<sup>+</sup> Lymphoproliferative Disorders Associated with a T-Helper 17 Cytokine Profile.
Specimen part, Subject
View SamplesWe report a simultaneous comparison of striatal mRNA levels by RNA sequencing mice with graded levels of HD-like abnormalities Overall design: Examination of 4 different mouse lines
Allelic series of Huntington's disease knock-in mice reveals expression discorrelates.
Specimen part, Subject
View SamplesThiazolidinediones (TZDs) are agonists at peroxisome proliferator-activated gamma-type (PPAR-y) receptors and are used clinically for the treatment of type 2 diabetes where they have been shown to reestablish insulin sensitivity, improve lipids profile, and reduce inflammation. Recent work also suggests that TZDs may be beneficial in Alzheimer's disease (AD), ameliorating cognitive decline early in the disease process. However, there have been only a few studies identifying mechanisms through which cognitive benefits may be exerted. Starting at 10 months of age, the triple transgenic mouse model of AD (3xTg-AD) with accelerated amyloid-B (AB) deposition and tau pathology was treated with the TZD pioglitazone (PIO- Actos) at 18 mg/Kg body weight/day. After four months, PIO-treated animals showed multiple beneficial effects, including improved learning on the active avoidance task, reduced serum cholesterol, decreased hippocampal AB deposits, and enhanced short- and long-term plasticity. Baseline electrophysiological membrane properties and blood glucose levels were unchanged by PIO treatment. Gene microarray analyses of hippocampal tissue identified predicted transcriptional responses following TZD treatment as well as potentially novel targets of TZDs, including facilitation of estrogenic processes, and decreases in glutamatergic and ketone metabolic/ cholesterol dependent processes. Taken together, these results confirm prior animal studies showing that TZDs can ameliorate cognitive deficits associated with AD-related pathology, but also extend these findings by pointing to novel molecular targets in the brain.
Long-term pioglitazone treatment improves learning and attenuates pathological markers in a mouse model of Alzheimer's disease.
Sex, Age
View SamplesHuman subjects were randomized for treatment with a GnRH-analogue, Goserelin, which suppresses endogenous testosterone or placebo for 12 weeks. Strength training was performed during the last 8 weeks. The suppression of testosterone resulted in an attenuation of the normal muscle adaptation to strength training (increased muscle mass and strength). To identify molecular signals involved in the response to testosterone levels, biopsies were obtained 4 hours after the last training session and gene expression compared with Affymetrix 3' microarrays. This timepoint should capture goserelin effect on both constitutive expression, training induced changes as well as acute exercise induced (4 hours) differences in mRNA levels.
The activity of satellite cells and myonuclei following 8 weeks of strength training in young men with suppressed testosterone levels.
Sex, Age, Specimen part, Treatment
View Samplesthere is presently no methodology that adequately isolates pure MaSCs. Seeking new markers of MaSCs, we characterized the stem-like properties and expression signature of label-retaining cells from the mammary gland of mice expressing a controllable H2b-GFP transgene. According to their transcriptome profile, H2b-GFPh MaSCs are enriched for pathways thought to play important roles in adult stem cells.
Molecular hierarchy of mammary differentiation yields refined markers of mammary stem cells.
No sample metadata fields
View SamplesProgenitors in human vasculature expanded in-vitro were differentiated with adipogenic cocktail for 12 days, following which they were stimulated with forskolin for 7 days
Human 'brite/beige' adipocytes develop from capillary networks, and their implantation improves metabolic homeostasis in mice.
Specimen part, Treatment
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