In the past decade, several transcription factors critical for pancreas development have been identified. Despite this success, many of the cell surface and extracellular factors necessary for proper islet morphogenesis and function remain uncharacterized. Previous studies have shown that transgenic over-expression of the transcription factor HNF6 specifically in the pancreatic endocrine cell lineage resulted in the disruption of islet morphogenesis, including dysfunctional endocrine cell sorting, increased islet size, and failure of islets to migrate away from the ductal epithelium. We exploited the dysmorphic islets in pdx1PBHnf6 animals as a tool to identify factors important for islet morphogenesis. Genome-wide microarray analysis was used to identify differences in the gene expression profiles of late gestation and early postnatal pancreas tissue from wild type and pdx1PBHnf6 animals. We report the identification of genes with an altered expression in HNF6 Tg animals and highlight factors with potential importance in islet morphogenesis.
Gene expression profiling of a mouse model of pancreatic islet dysmorphogenesis.
Specimen part
View SamplesWarfare has long been associated with traumatic brain injury (TBI) in militarized zones. Common forms of TBI can be caused by a physical insult to the head-brain or by the effects of a high velocity blast shock wave generated by the detonation of an explosive device. While both forms of trauma are distinctly different regarding the mechanism of trauma induction, there are striking similarities in the cognitive and emotional status of survivors. Presently, proven effective therapeutics for the treatment of either form of TBI are unavailable. To be able to develop efficacious therapies, studies involving animal models of physical- and blast-TBI are required to identify possible novel or existing medicines that may be of value in the management of clinical events. We examined indices of cognition and anxiety-like behavior and the hippocampal gene transcriptome of mice subjected to both forms of TBI. We identified common behavioral deficits and gene expression regulations, in addition to unique injury-specific forms of gene regulation. Molecular pathways presented a pattern similar to that seen in gene expression. Interestingly, pathways connected to Alzheimers disease displayed a markedly different form of regulation depending on the type of TBI. While these data highlight similarities in behavioral outcomes after trauma, the divergence in hippocampal transcriptome observed between models suggests that, at the molecular level, the TBIs are quite different. These models may provide tools to help define therapeutic approaches for the treatment of physical- and blast-TBIs. Based upon observations of increasing numbers of personnel displaying TBI related emotional and behavioral changes in militarized zones, the development of efficacious therapies will become a national if not a global priority.
Changes in mouse cognition and hippocampal gene expression observed in a mild physical- and blast-traumatic brain injury.
Sex, Specimen part, Treatment, Time
View SamplesBMP9 signaling has been implicated in hereditary hemorrhagic telangiectasia and vascular remodeling, acting via the HHT target genes, endoglin and ALK1. This study sought to identify endothelial BMP9-regulated proteins that could affect the HHT phenotype. Gene ontology analysis of cDNA microarray data obtained following BMP9 treatment of primary human endothelial cells indicated regulation of chemokine, adhesion, and inflammation pathways.
BMP9 regulates endoglin-dependent chemokine responses in endothelial cells.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Blast traumatic brain injury-induced cognitive deficits are attenuated by preinjury or postinjury treatment with the glucagon-like peptide-1 receptor agonist, exendin-4.
Sex, Specimen part, Treatment, Time
View SamplesBlast traumatic brain injury (B-TBI) affects military and civilian personnel. Presently there are no approved drugs for blast brain injury. Exendin-4, administered subcutaneously, was evaluated as a pre-treatment (48 hours) and post-injury treatment (2 hours) on neurodegeneration, behaviors and gene expressions in a murine open field model of blast injury. B-TBI induced neurodegeneration, changes in cognition and genes expressions linked to dementia disorders. Exendin-4, administered pre- or post-injury ameliorated B-TBI-induced neurodegeneration at 72 hours, memory deficits from days 7-14 and attenuated genes regulated by blast at day 14 post-injury. The present data suggest shared pathological processes between concussive and B-TBI, with endpoints amenable to beneficial therapeutic manipulation by exendin-4. B-TBI-induced dementia-related gene pathways and cognitive deficits in mice somewhat parallel epidemiological studies of Barnes and co-workers who identified a greater risk in US military veterans who experienced diverse TBIs, for dementia in later life.
Blast traumatic brain injury-induced cognitive deficits are attenuated by preinjury or postinjury treatment with the glucagon-like peptide-1 receptor agonist, exendin-4.
Sex, Specimen part
View SamplesTraumatic brain injury (TBI) is a global problem reaching near epidemic numbers that manifests clinically with cognitive problems that decades later may result in dementias like Alzheimers disease (AD). Presently, little can be done to prevent ensuing neurological dysfunctions by pharmacological means. Recently, it has become apparent that several CNS diseases share common terminal features of neuronal cell death. The effects of exendin-4 (Ex-4), a neuroprotective agent delivered via a subcutaneous micro-osmotic pump, were examined in the setting of mild TBI (mTBI). Utilizing a model of mTBI, where cognitive disturbances occur over time, animals were subjected to four treatments: sham; Ex-4; mTBI and Ex-4/mTBI. mTBI mice displayed deficits in novel object recognition, while Ex-4/mTBI mice performed similar to sham. Hippocampal gene expression, assessed by gene array methods, showed significant differences with little overlap in co-regulated genes between groups. Importantly, changes in gene expression induced by mTBI, including genes associated with AD were largely prevented by Ex-4. These data suggest a strong beneficial action of Ex-4 in managing secondary events induced by a traumatic brain injury.
Exendin-4, a glucagon-like peptide-1 receptor agonist prevents mTBI-induced changes in hippocampus gene expression and memory deficits in mice.
Sex, Specimen part, Treatment, Time
View SamplesThe discovery of genetic variants in the CHRNA5-CHRNA3-CHRNB4 gene cluster associated with heavy smoking and higher relapse risk has led to the identification of the midbrain habenula- interpeduncular axis as a critical relay circuit in the control of nicotine addiction
Reexposure to nicotine during withdrawal increases the pacemaking activity of cholinergic habenular neurons.
Specimen part, Disease
View SamplesBackground In flowering plants, the anther is the site of male gametophyte development. Two major events in the development of the male germline are meiosis and the asymmetric division in the male gametophyte that gives rise to the vegetative and generative cells, and the following mitotic division in the generative cell that produces two sperm cells. Anther transcriptomes have been analyzed at progressive stages of development by using microarray and sequence by synthesis technologies to identify genes that regulate anther development. Here we have carried out a comprehensive analysis of rice anther transcriptomes at four distinct stages of development with a focus to identify regulatory components contributing to male meiosis and germline development. Further, these transcriptomes have been compared with transcriptomes of 10 stages of rice vegetative and seed development to identify genes that express specifically during anther development. Results - To understand the molecular processes that lead to male gametophyte development, transcriptome profiling of four stages of anther development in rice [pre-meiotic (PMA), meiotic (MA), anthers at single-celled (SCP) and tri-nucleate pollen (TPA)] was conducted. Around 22,000 genes were found to be expressed in at least one of the anther developmental stages, with the highest number in MA (18,090) and lowest (15,465) in TPA. Comparison of these transcriptome profiles to an in-house generated microarray-based transcriptomics database comprising of 10 stages/tissues of vegetative as well as reproductive development in rice resulted in the identification of1,000 genes that are specifically expressed in anther stages. Of them the expression of 453 genes was found to be specific to TPA, whereas 78 and 184 genes were expressed specifically in MA and SCP. Gene ontology and pathway analysis of specifically expressed genes revealed that transcription factors and protein folding, sorting and degradation pathway genes dominated in MA, whereas in TPA, those coding for cell structure and signal transduction components were in abundance. Interestingly, about 50% of the genes with anther-specific expression have not been annotated so far. Conclusions - These data not only provide the transcriptome constituents of four landmark stages of anther development but also identify genes that express exclusively in these stages and therefore may contribute to specific aspects of anther and/or male gametophyte development in rice. Moreover, these gene sets assist in building a deeper understanding of underlying regulatory networks and in selecting candidates for gene function validation.
Analysis of anther transcriptomes to identify genes contributing to meiosis and male gametophyte development in rice.
Specimen part
View SamplesOur work demonstrated that miR-183 cluster regulates IFN production and signaling
A conserved miRNA-183 cluster regulates the innate antiviral response.
Cell line
View SamplesOur understanding of the mechanisms that govern the cellular process of meiosis is limited in higher plants with polyploid genomes. Bread wheat is an allohexaploid that behaves as a diploid during meiosis. Chromosome pairing is restricted to homologous chromosomes despite the presence of homoeologues in the nucleus. The importance of wheat as a crop and the extensive use of wild wheat relatives in breeding programs has prompted many years of cytogenetic and genetic research to develop an understanding of the control of chromosome pairing and recombination. The rapid advance of biochemical and molecular information on meiosis in model organisms such as yeast provides new opportunities to investigate the molecular basis of chromosome pairing control in wheat. However, building the link between the model and wheat requires points of data contact. We report here a large-scale transcriptomics study using the Affymetrix wheat GeneChip aimed at providing this link between wheat and model systems and at identifying early meiotic genes. Analysis of the microarray data identified 1,350 transcripts temporally-regulated during the early stages of meiosis. Expression profiles with annotated transcript functions including chromatin condensation, synaptonemal complex formation,recombination and fertility were identified. From the 1,350 transcripts, 30 displayed at least an eight-fold expression change between and including pre-meiosis and telophase II, with more than 50% of these having no similarities to known sequences in NCBI and TIGR databases. This resource is now available to support research into the molecular basis of pairing and recombination control in the complex polyploid, wheat.
Microarray expression analysis of meiosis and microsporogenesis in hexaploid bread wheat.
Specimen part
View Samples