Parkinson's disease pathogenesis proceeds through several phases, culminating in the loss of dopaminergic neurons of the substantia nigra (SN). Although the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of oxidative SN injury is frequently used to study degeneration of dopaminergic neurons in mice and non-human primates, an understanding of the temporal sequence of molecular events from inhibition of mitochondrial complex 1 to neuronal cell death is limited. Here, microarray analysis and integrative data mining were used to uncover pathways implicated in the progression of changes in dopaminergic neurons after MPTP administration. This approach enabled the identification of small, yet consistently significant, changes in gene expression within the SN of MPTP-treated animals. Such an analysis disclosed dysregulation of genes in three main areas related to neuronal function: cytoskeletal stability and maintenance, synaptic integrity, and cell cycle and apoptosis. The discovery and validation of these alterations provide molecular evidence for an evolving cascade of injury, dysfunction, and cell death.
Dysregulation of gene expression in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned mouse substantia nigra.
Sex, Age, Specimen part
View SamplesThe immortalized human urothelial cell line, UROtsa, was transformed in six parallel cultures with continual passaging in1 M Cd+2 until the cells were able to attain the ability to form colonies in soft agar and subcutaneous tumors in nude mice. The gene expression profiles between cadmium-transformed and control samples were compared and the differentially expressed genes were identified.
Variation of keratin 7 expression and other phenotypic characteristics of independent isolates of cadmium transformed human urothelial cells (UROtsa).
Cell line
View SamplesA diverse pool of RNAs remain encapsulated within the transcriptionally and translationally silent spermatozoon. These transcripts persist within the male gamete despite the dramatic reduction in cellular volume achieved through expulsion of the cytoplasm and quite possibly the nucleoplasm. The precise location of RNAs retained within the sperm cell remains largely unknown. However, early evidence suggested that many are embedded within the nucleus (1). To discern the global pattern of transcript compartmentalization in sperm, total RNA was extracted from whole mouse spermatozoa and detergent demembranated nuclei fractionated through a sucrose gradient. Isolated RNAs were subjected to RNA-sequencing (RNA-seq) and their abundance used to infer localization. Transcripts enriched in the unfractionated cells were related to the production and function of mitochondria and surprisingly, exosomes. The absence of these extracellular vesicles associated RNAs within the inner-nuclear compartment was suggestive of an origin other than sperm. This contributes to the growing evidence for sperm-bound exosomes rich in RNA. In comparison, the majority of the remaining sperm RNAs were associated with the nucleus. This included the abundant fragmented ribosomal transcripts which likely persist between the nuclear envelope and the perinuclear theca. The spermatozoal inner-nuclear compartment was also enriched in repetitive transcribed sequences. This included LINE elements and simple repeat sequences both of which have been shown to contribute to chromatin structure in other cell types suggesting that they may serve parallel roles in the spermatozoon. Overall design: RNA-seq analysis of whole mouse sperm and fractionated nuclei
The protein and transcript profiles of human semen.
No sample metadata fields
View SamplesUsing cell-restricted transcriptome analysis, here we show that Drosophila ommatidial cone (or Semper) cells are enriched for conserved glial regulators and effectors, including many characteristic of vertebrate retinal glia: Müller glia and astrocytes. Overall design: RNA-seq based analysis of Drosophila retinal cone cells (3 developmental stages) and photoreceptors. 1 sample per cell type - 4 total libraries sequenced.
Multifunctional glial support by Semper cells in the Drosophila retina.
Specimen part, Subject
View SamplesHow cells acquire their fate is a fundamental question in both developmental and regenerative biology. Multipotent progenitors undergo gradual cell fate restriction in response to temporal and positional cues from the microenvironment, the nature of which is far from being clear. In the case of the lymphatic system, venous endothelial cells are thought to give rise to lymphatic vessels, through a process of trans-differentiation. Upon expression of a set of transcription factors, venous cells acquire a lymphatic fate, and bud out to generate the lymphatic vasculature. In this work we challenge this view and show that while lymphatic endothelial cells (LECs) do arise in the Cardinal Vein (CV), they do so from a previously uncharacterized pool of multipotent angioblasts. Using lymphatic-specific transgenic zebrafish, in combination with endothelial photoconvertible reporters, and long-term live imaging, we demonstrate that these multipotent angioblasts can generate not only lymphatic, but also arterious, and venous fates. We further reveal that the underlying endoderm serves as a source of Wnt5b, which acts as a lymphatic inductive signal, promoting the angioblast-to-lymphatic transition. Moreover, Wnt5b induced lymphatic specification in human embryonic stem cells- derived vascular progenitors, suggesting that this process is evolutionary conserved. Our results uncover a novel mechanism of lymphatic vessel formation, whereby multipotent angioblasts and not venous endothelial cells give rise to the lymphatic endothelium, and provide the first characterization of their inductive niche. More broadly, our findings highlight the CV as a plastic and heterogeneous structure containing different cell populations, analogous to the hematopoietic niche in the aortic floor. Overall design: Following Kaede photoconversion of dorsal or ventral halves of the PCV in Tg(fli1:gal4;uasKaede) embryos at 24 hpf, 6Â embryos per group were used for FACS isolation of Kaede photconverted (red) ECs.
Lymphatic vessels arise from specialized angioblasts within a venous niche.
No sample metadata fields
View SamplesNeuronal function critically depends on coordinated subcellular distribution of mRNAs. Disturbed mRNA processing and axonal transport has been found in spinal muscular atrophy and could be causative for dysfunction and degeneration of motoneurons. Despite the advances made in characterizing the transport mechanisms of several axonal mRNAs, an unbiased approach to identify the axonal repertoire of mRNAs in healthy and degenerating motoneurons has been lacking. Here we used compartmentalized microfluidic chambers to investigate the somatodendritic and axonal mRNA content of cultured motoneurons by microarray analysis. In axons, transcripts related to protein synthesis and energy production were enriched relative to the somatodendritic compartment. Knockdown of Smn, the protein deficient in spinal muscular atrophy, produced a large number of transcript alterations in both compartments. Transcripts related to immune functions, including MHC class I genes, and with roles in RNA splicing were upregulated in the somatodendritic compartment. On the axonal side, transcripts associated with axon growth and synaptic activity were downregulated. These alterations provide evidence that subcellular localization of transcripts with axonal functions as well as regulation of specific transcripts with nonautonomous functions is disturbed in Smn-deficient motoneurons, most likely contributing to the pathophysiology of spinal muscular atrophy.
Subcellular transcriptome alterations in a cell culture model of spinal muscular atrophy point to widespread defects in axonal growth and presynaptic differentiation.
Specimen part
View SamplesRNA-Seq technique was applied to investigate the effects of four cDNA amplification kits and two RNA-Seq library preparation kits to the deep sequencing results at different perspectives. Overall design: The same set of semen samples were applied to investigate the qualitative and quantitative effect of four cDNA amplification methods and two RNA-Seq library preparation methods on sperm transcript profiling.
A comparison of sperm RNA-seq methods.
No sample metadata fields
View SamplesGenomic imprinting is an allele-specific gene expression system important for mammalian development and function. The molecular basis of genomic imprinting is allele-specific DNA methylation 2. While it is well known that the de novo DNA methyltransferases Dnmt3a/b are responsible for the establishment of genomic imprinting, how the methylation mark is erased during primordial germ cell (PGC) reprogramming remains a mystery. Here we report that Tet1 plays a critical role in the erasure of genomic imprinting. We show that despite their identical genotype, progenies derived from mating between Tet1-KO males and wild-type females exhibit a number of variable phenotypes including placental, fetal and postnatal growth defects, and early embryonic lethality. These defects are, at least in part, caused by the dysregulation of imprinted genes, such as Peg10 and Peg3, which exhibit aberrant hypermethylation in the paternal allele of differential methylated regions (DMRs). RNA-seq reveals extensive dysregulation of imprinted genes in the next generation due to paternal functional loss of Tet1. Genome-wide DNA methylation analysis of E13.5 PGCs and sperm derived from Tet1-KO mice reveals hypermethylation of DMRs of imprinted genes in sperm, which can be traced back to PGCs. Dynamics of methylation change in Tet1-affected sites suggested that Tet1 swipes remaining methylation including imprinted genes at late reprogramming stage. We also revealed that Tet1play a role in paternal imprinting erasure in females germline. Thus, our study establishes a critical function for Tet1 in the erasure of genomic imprinting. Overall design: Gene expression analysis of E9.5 embryos
Role of Tet1 in erasure of genomic imprinting.
Specimen part, Subject
View SamplesClassical embryological studies revealed that during mid-embryogenesis vertebrates show similar morphologies. This “phylotypic stage” has recently received support from transcriptome analyses, which have also detected similar stages in nematodes and arthropods. A conserved stage in these three phyla has led us to ask if all animals pass through a universal definitive stage as a consequence of ancestral constraints on animal development. Previous work has suggested that HOX genes may comprise such a ‘zootypic’ stage, however this hypothetical stage has hitherto resisted systematic analysis. We have examined the embryonic development of ten different animals each of a fundamentally different phylum, including a segmented worm, a flatworm, a roundworm, a water bear, a fruitfly, a sea urchin, a zebrafish, a sea anemone, a sponge, and a comb jelly. For each species, we collected the embryonic transcriptomes at ~100 different developmental stages and analyzed their gene expression profiles. We found dynamic gene expression across all of the species that is structured in a stage like manner. Strikingly, we found that animal embryology contains two dominant modules of zygotic expression in terms of their protein domain composition: one involving proliferation, and a second involving differentiation. The switch between these two modules involves induction of the zootype; which in addition to homeobox containing genes, also involves Wnt and Notch signaling as well as forkhead domain transcription factors. Our results provide a systematic characterization of animal universality and identify the points of embryological constraints and flexibility. Overall design: 139 single embryo samples.
The mid-developmental transition and the evolution of animal body plans.
Subject
View SamplesClassical embryological studies revealed that during mid-embryogenesis vertebrates show similar morphologies. This “phylotypic stage” has recently received support from transcriptome analyses, which have also detected similar stages in nematodes and arthropods. A conserved stage in these three phyla has led us to ask if all animals pass through a universal definitive stage as a consequence of ancestral constraints on animal development. Previous work has suggested that HOX genes may comprise such a ‘zootypic’ stage, however this hypothetical stage has hitherto resisted systematic analysis. We have examined the embryonic development of ten different animals each of a fundamentally different phylum, including a segmented worm, a flatworm, a roundworm, a water bear, a fruitfly, a sea urchin, a zebrafish, a sea anemone, a sponge, and a comb jelly. For each species, we collected the embryonic transcriptomes at ~100 different developmental stages and analyzed their gene expression profiles. We found dynamic gene expression across all of the species that is structured in a stage like manner. Strikingly, we found that animal embryology contains two dominant modules of zygotic expression in terms of their protein domain composition: one involving proliferation, and a second involving differentiation. The switch between these two modules involves induction of the zootype; which in addition to homeobox containing genes, also involves Wnt and Notch signaling as well as forkhead domain transcription factors. Our results provide a systematic characterization of animal universality and identify the points of embryological constraints and flexibility. Overall design: 106 single embryo samples
The mid-developmental transition and the evolution of animal body plans.
No sample metadata fields
View Samples