Project description:Choroid plexus secretes cerebrospinal fluid important for brain development and homeostasis. The OTX2 homeoprotein is critical for choroid plexus development and remains highly expressed in adult choroid plexus. Through RNA sequencing analyses of constitutive and conditional knockdown adult mouse models, we reveal putative roles for OTX2 in choroid plexus function, including cell signaling and adhesion, and show that it regulates the expression of factors secreted into cerebrospinal fluid, notably transthyretin. We also show that Otx2 expression impacts choroid plexus immune and stress responses, and also affects splicing which leads to changes in mRNA isoforms of proteins implicated in oxidative stress response and DNA repair. Through mass spectrometry analysis of OTX2 protein partners in the choroid plexus, and in known non-cell autonomous target regions such as visual cortex and subventricular zone, we identified putative targets involved in cell adhesion, chromatin structure and RNA processing. Thus, OTX2 retains important roles in choroid plexus function and brain homeostasis throughout life.
Project description:To analyze OTX2 function in adult choroid plexus, we performed several OTX2 co-immunoprecipitation (co-IP) experiments with mass spectrometry analysis to identify potential protein partners. We previously discovered that OTX2 protein also accumulates non-cell autonomously in subventricular zone (SVZ) and rostral migratory stream (RMS) astrocytes and in visual cortex (VCx) parvalbumin cells. The identification of alternate protein partners in cell-autonomous and non-cell-autonomous contexts would suggest OTX2 takes on specific roles after transferring between cells. In order to test this hypothesis, and to reinforce choroid plexus analysis, we also performed OTX2 co-IP on lysates from adult mouse SVZ, RMS and VCx.
Project description:The choroid plexuses (ChPs) are the main regulators of cerebrospinal fluid (CSF) composition and thereby also control the composition of a principal source of signaling molecules that is in direct contact with neural stem cells in the developing brain. The regulators of ChP development mediating the acquisition of a fate that differs from the neighboring neuroepithelial cells are poorly understood. Here, we demonstrate in mice a crucial role for the transcription factor Otx2 in the development and maintenance of ChP cells. Deletion of Otx2 by the Otx2-CreERT2 driver line at E9 resulted in a lack of all ChPs, whereas deletion by the Gdf7-Cre driver line affected predominately the hindbrain ChP, which was reduced in size, primarily owing to an increase in apoptosis upon Otx2 deletion. Strikingly, Otx2 was still required for the maintenance of hindbrain ChP cells at later stages when Otx2 deletion was induced at E15, demonstrating a central role of Otx2 in ChP development and maintenance. Moreover, the predominant defects in the hindbrain ChP mediated by Gdf7-Cre deletion of Otx2 revealed its key role in regulating early CSF composition, which was altered in protein content, including the levels of Wnt4 and the Wnt modulator Tgm2. Accordingly, proliferation and Wnt signaling levels were increased in the distant cerebral cortex, suggesting a role of the hindbrain ChP in regulating CSF composition, including key signaling molecules. Thus, Otx2 acts as a master regulator of ChP development, thereby influencing one of the principal sources of signaling in the developing brain, the CSF. We performed gene expression microarray analysis of fourth ventricular choroid plexus tissue from Otx2 k.o. mice compared to wildtype mice from the same litters.
Project description:These tissue were harvested to complement and extend the studies that generated GSE23093. They served 3 purposes; 1) identify genes important to choroid plexus function and compare them with those important for meninges and associated vasculature (MAV) function, 2) determine genes in the choroid plexus and sensitivity hyperthermia and amphetamine toxicity, 3) identify the important gene expression changes related to the immune system in MAV, choroid plexus and trunk' blood Gene mRNA expression patterns in choroid plexus and trunk blood were determined under control conditions as well as after (3 hr and 1day) exposure to either environmentally-induced hyperthermia or neurotoxic doses of amphetamine. This data was analyzed and compared to data from meninges and associated vasculature previously deposited in GEO. The data gathered under control conditions was used to further understand how the choroid plexus and meninges and associated vasculature might function to generate and regulate the cerebrospinal fluid. The expression patterns in the choroid plexus after environmentally-induced hyperthermia or neurotoxic doses of amphetamine was determine its damage and protective responses. The expression patterns after environmentally-induced hyperthermia or neurotoxic doses of amphetamine were compared among choroid plexus, meninges and associated vasculature and blood were analyzed to determine immune system responses.
Project description:Gene expression profiles generated from human tumor cells laser-microdissected from surgical samples of seven choroid plexus papillomas (Grade I WHO) as eight samples of epithelial cells lasermicrodissected from normal choroid plexus obtained at autopsy. Choroid plexus tumors are rare pediatric brain tumors derrived from the choroid plexus epithelium. Gene expression profiles of lasermicrodissected tumor cells from 7 individual choroid plexus tumor samples obtained at surgery were compared to gene expression profiles from non-neoplastic choroid plexus epithelial cells lasermicrodissected from normal non-neoplastic choroid plexus obtained at autopsy (Am J Surg Pathol. 2006 Jan;30(1):66-74.) in order to identfy genes differentially expressed in choroid plexus tumor cells.
Project description:Atoh1-Cre; Myc/Myc mice developed choroid plexus papilloma and Atoh1-Cre; Myc/Myc; p53fl/fl mice developed choroid plexus carcinoma. By studying the gene expression profiles of normal choroid plexus, choroid plexus papilloma and choroid plexus carcinoma in mice, we aim to gain a better understanding of the biology of choroid plexus tumors
Project description:These tissue were harvested to complement and extend the studies that generated GSE23093. They served 3 purposes; 1) identify genes important to choroid plexus function and compare them with those important for meninges and associated vasculature (MAV) function, 2) determine genes in the choroid plexus and sensitivity hyperthermia and amphetamine toxicity, 3) identify the important gene expression changes related to the immune system in MAV, choroid plexus and trunk' blood
Project description:The choroid plexus is an important source of trophic factors for the developing and mature brain. Recently we described the expression and production of mature insulin in epithelial cells of the choroid plexus, and how its secretion can be modulated by serotonin through Htr2c, a metabotropic receptor that signals via Gq. To understand the function of this choroid plexus-derived insulin, here we describe a way to genetically target epithelial cells of the choroid plexus using a viral vector. With this, we modulated insulin expression and evaluated behavior. Insulin overexpression in the choroid plexus of wild type mice led to an inhibition in feeding, whereas insulin knockdown in choroid plexus of Ins1-/-Ins2fl/fl mice promoted discrete increases in food intake, especially after a period of fasting. Insulin overexpression in choroid plexus induced roust transcriptomic changes in the hypothalamus, most of which related to axonal growth and synapse-related processes. Finally, activation of Gq signaling in insulin-overexpressing choroid plexuses led to acute AKT phosphorylation in neurons of the arcuate nucleus, suggesting a direct action, through the CSF, of choroid plexus-derived insulin on the hypothalamus. Taken together our findings prove that the choroid plexus is a relevant source of insulin in the central nervous system, with physiological implications in feeding behavior. We believe that choroid plexus-derived insulin has to be taken into consideration in future work pertaining insulin actions in the brain.
Project description:The choroid plexus produces cerebrospinal fluid (CSF) by transport of electrolytes and water from the vasculature to the brain ventricles. The choroid plexus plays additional roles in brain development and homeostasis by secreting neurotrophic molecules, and by serving as a CSF-blood barrier and immune interface. Prior studies have identified transporters on the epithelial cells that transport water and ions into the ventricles and tight junctions involved in the CSF-blood barrier. Yet, how the choroid plexus epithelial cells maintain the brain ventricle system and control brain physiology remain unresolved. To provide novel insights into the physiological roles of the choroid plexus, we use juvenile and adult zebrafish as model systems. Upon histological and transcriptomic analyses, we first identified that the zebrafish choroid plexus is highly conserved with the mammalian choroid plexus and that it expresses all transporters necessary for CSF secretion. Using novel genetic lines, we also identified that the choroid plexus secretes proteins into the CSF. Next, we generated a transgenic line allowing us to ablate specifically the epithelial cells in the choroid plexus. Using the ablation system, we identified a reduction of the ventricular sizes, but no alterations of the CSF-blood barrier. Altogether, our findings identified that the zebrafish choroid plexus is evolutionarily conserved and critical for maintaining the size and homeostasis of the brain ventricles.