Gamma oscillations (20-50Hz) are a common local field potential signature in many brain regions that are generated by a resonant circuit between fast-spiking parvalbumin (PV)-positive interneurons and pyramidal cells. Changes in the magnitude and frequency of gamma have been observed in several neuropsychiatric disorders. However, it is unclear how disruptions in gamma oscillations affect cellular pathologies seen in these disorders. Here, we investigate this using the 5XFAD mouse model of Alzheimer’s disease (AD) and find reduced power and magnitude of behaviorally driven gamma oscillatory activity — even before the onset of plaque formation or measurable cognitive decline. Because of the early onset, we aimed to determine if exogenous manipulations of gamma could influence the progression of disease pathology. We find that driving PV-positive neurons at gamma frequency (40Hz) using channelrhodopsin-2 reduced total levels of amyloid-ß (Aß) 40 and 42 isoforms in the hippocampus of 5XFAD mouse. Driving PV-positive neurons at other frequencies, or driving excitatory neurons, did not reduce Aß levels. Furthermore, driving PV-positive neurons reduced enlarged endosomes in hippocampal neurons and cleavage intermediates of APP in 5XFAD mouse. Gene expression profiling revealed a neuroprotective response with morphological transformation of microglia and markedly increased phagocytosis of Aß by microglia. Inspired by these observations, we designed a non-invasive light-flickering paradigm that drives 40Hz gamma activity in mouse visual cortex. The light-flickering paradigm profoundly reduced Aß40 and Aß42 levels in the visual cortex of pre-symptomatic mice and greatly mitigated plaque load in the visual cortex of aged, symptomatic mice. This reduction was completely blocked by a GABA-A antagonist, providing further support for an essential role of GABAergic signaling in mediating neuroprotective gamma activity. Overall, our findings uncover a dramatic and previously unappreciated function of the brain’s endogenous gamma rhythms in reducing the production and increasing the clearance of Aß peptides, whose accumulation is believed to drive the pathogenesis of AD. Overall design: Two to four weeks following virus injection and implant placement, hippocampal CA1 neurons were optigenetically manipulated. During the experiment, 1mW of optical stimulation was delivered for 1h using a 40Hz stimulation protocol.
Gamma frequency entrainment attenuates amyloid load and modifies microglia.
Age, Specimen part, Cell line, Subject
View SamplesMicroRNAs have been implicated in the molecular pathogenesis of calcineurin inhibitor nephrotoxicity. However, identification of bona fide physiologically relevent miRNA/mRNA targeting interactions remains a challenge. To define a comprehensive miRNA/mRNA targetome and determine the role of miRNAs in cyclsporine-induced nephrotoxicity, we performed PAR-CLIP (Photoactivatable-Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation) against endogenous Argonaute 2 (AGO2) protein in human proximal tubule cells treated with cyclosporine A (CsA) or vehicle control. Statistically significant mRNA targets of miRNAs in the RNA Inducing Silencing Complex (RISC) complex were identified by PIPE-CLIP, a bioinformatic framework based on a zero-truncated negative binomial model. Further, we determined the total cellular differential expression of miRNAs and mRNAs by conventional deep sequencing methods. Our data indicate that CsA causes specific changes in miRNAs and mRNAs associated with the RISC complex. A relatively small fraction of the miRNAs and mRNAs identified by total cell RNA-seq were also found in the RISC complex suggesting that changes in targeting by miRs are not necessarily reflected in changes observed in total cellular RNA. Pathway enrichment analysis after integrating miRNA-seq, mRNA-seq, and PAR-CLIP datasets identified canonical pathways specifically under regulation by miRNAs following CsA treatment. Our analysis indicates that miRNAs play an integral role in regulating widespread dysregulation of the proximal tubule cell gene program, contributing to alterations in cell-cell adhesion, integrin-cytoskeleton signaling, and calcium signaling. Analysis of high confidence 3''UTR targets revealed a specific role for miR-101-3p in regulating MAPK signaling which may contribute to the pathogenesis of cyclosporine-induced nephrotoxicity in a calcineurin-independent manner. Overall design: AGO2-PAR-CLIP, mRNA-seq, and miRNA-seq of a human kidney proximal tubule cell line (HK-2) treated with cyclosporine A or vehicle control was performed and sequenced by Illumina HiSeq 2500. Two replicate AGO2-PAR-CLIP samples in each condition and four replicates in each condition for mRNA-seq and miRNA-seq were obtained.
Defining a microRNA-mRNA interaction map for calcineurin inhibitor induced nephrotoxicity.
No sample metadata fields
View SamplesImplications for neuroprotection in Parkinson's disease
VTA neurons show a potentially protective transcriptional response to MPTP.
Specimen part, Treatment
View SamplesThe blockage of GABA-A ionotropic channels by means of gabazine is a widespread model of plasticity where the increased synaptic activity triggered by Gabazine leads to the up-regulation of a plethora of activity-dependent genes. Here, we sought to characterize the overall transcriptional response of GABA-A blocking of rat hippocampal organotypic cultures.
Early phase of plasticity-related gene regulation and SRF dependent transcription in the hippocampus.
Specimen part, Treatment
View SamplesArabidopsis thaliana MYB80 (formerly MYB103) is expressed in the tapetum and microspores between anther developmental stages 6 and 10. MYB80 encodes a MYB transcription factor that is essential for tapetal and pollen development. In order to identify the genes regulated by MYB80, microarray technology was employed to analyze the expression levels of genes that were differentially regulated in the myb80 mutant and wild- type anthers.
The MYB80 transcription factor is required for pollen development and the regulation of tapetal programmed cell death in Arabidopsis thaliana.
Specimen part
View SamplesThere is emerging evidence that, beyond their cholesterol lowering properties, statins exhibit important antileukemic effects in vitro and in vivo, but the precise mechanisms by which they generate such responses remain to be determined. We have previously shown that statins promote differentiation of acute promyelocytic leukemia (APL) cells and enhance generation of all-trans-retinoic acid (ATRA)-dependent antileukemic responses. We now provide evidence that statin-dependent leukemic cell differentiation requires engagement and activation of the JNK kinase pathway. In addition, in experiments to define the molecular targets and mediators of statin-induced differentiation we found a remarkable effect of statins on ATRA-dependent gene transcription, evidenced by the selective induction of over 400 genes by the combination of atorvastatin and ATRA. Altogether, our studies identify novel statin molecular targets linked to differentiation, establish that statins modulate ATRA-dependent transcription, and suggest that combined use of statins with retinoids may provide a novel approach to enhance antileukemic responses in APL and possibly other leukemias.
Regulation of leukemic cell differentiation and retinoid-induced gene expression by statins.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
HoxA3 is an apical regulator of haemogenic endothelium.
Specimen part
View SamplesWe used a murine ES cell line in which HoxA3 expression is under control of a tetracycline-responsive element and differentiated these cells as embryoid bodies (EBs). Endothelial (Flk-1 VE-cadherin double positive, FV) and hematopoieitc progenitors (c-Kit CD41 double positive, K41) were isolated from differentiated EBs that had been induced for 6 hours by doxycycline (Dox) treatment.
HoxA3 is an apical regulator of haemogenic endothelium.
Specimen part
View SamplesThe ability to assign expression patterns to individual cell types that constitute a tissue is a major challenge in RNA expression analysis. This especially applies to brain given the plethora of different cells coexisting in that tissue. Here, we derived cell-type specific transcriptome signatures from existing single cell RNA data and integrated these signatures with a newly generated dataset of expression (bulk RNA-seq) of the postnatal developing hippocampus. This integrated analysis allowed us to provide a comprehensive and unbiased prediction of the differentiation drivers for 10 different hippocampal cell types and describe how the different cell types interact to support crucial developmental stages. Our integrated analysis provides a reliable resource of predicted differentiation drivers and insight into the multifaceted aspects of the cells in hippocampus during development. Overall design: 21 RNA-seq samples. For the stages E15, P1, P7, P15, and P30, there are respectively 3, 4, 3, 3, and 6 RNA-seq biological replica (total 19). One RNA-seq sample has two technical replica.
Integrated transcriptional analysis unveils the dynamics of cellular differentiation in the developing mouse hippocampus.
Specimen part, Cell line, Subject
View Samplesp63 mutations have been associated with several human hereditary disorders characterized by ectodermal dysplasia such as EEC syndrome, ADULT syndrome and AEC syndrome . The location and functional effects of the mutations that underlie these syndromes reveal a striking genotype-phenotype correlation. Unlike EEC and ADULT that result from missense mutations in the DNA-binding domain of p63, AEC is solely caused by missense mutations in the SAM domain of p63. We report a study on the TAp63a isoform, the first to be expressed during development of the embryonic epithelia, and on its naturally occurring Q540L mutant derived from an AEC patient. To assess the effects of the Q540L mutation, we generated stable cell lines expressing TAp63a wt, DeltaNp63 alpha or the TAp63 alpha-Q540L mutant protein and used them to systematically compare the cell growth regulatory activity of the mutant and wt p63 proteins and to generate, by microarray analysis, a comprehensive profile of differential gene expression. We found that the Q540L substitution impairs the transcriptional activity of TAp63a and causes misregulation of genes involved in the control of cell growth and epidermal differentiation.
The Hay Wells syndrome-derived TAp63alphaQ540L mutant has impaired transcriptional and cell growth regulatory activity.
No sample metadata fields
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