Dataset Information

Evidence for baseline retinal pigment epithelium pathology in the Trp1-Cre mouse.

ABSTRACT: The increasing popularity of the Cre/loxP recombination system has led to the generation of numerous transgenic mouse lines in which Cre recombinase is expressed under the control of organ- or cell-specific promoters. Alterations in retinal pigment epithelium (RPE), a multifunctional cell monolayer that separates the retinal photoreceptors from the choroid, are prevalent in the pathogenesis of a number of ocular disorders, including age-related macular degeneration. To date, six transgenic mouse lines have been developed that target Cre to the RPE under the control of various gene promoters. However, multiple lines of evidence indicate that high levels of Cre expression can be toxic to mammalian cells. In this study, we report that in the Trp1-Cre mouse, a commonly used transgenic Cre strain for RPE gene function studies, Cre recombinase expression alone leads to RPE dysfunction and concomitant disorganization of RPE layer morphology, large areas of RPE atrophy, retinal photoreceptor dysfunction, and microglial cell activation in the affected areas. The phenotype described herein is similar to previously published reports of conditional gene knockouts that used the Trp1-Cre mouse, suggesting that Cre toxicity alone could account for some of the reported phenotypes and highlighting the importance of the inclusion of Cre-expressing mice as controls in conditional gene targeting studies.

SUBMITTER: Thanos A

PROVIDER: S-EPMC3349832 | biostudies-other | 2012 May

REPOSITORIES: biostudies-other

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Evidence for baseline retinal pigment epithelium pathology in the Trp1-Cre mouse.

Thanos Aristomenis A Morizane Yuki Y Murakami Yusuke Y Giani Andrea A Mantopoulos Dimosthenis D Kayama Maki M Roh Mi In MI Michaud Norman N Pawlyk Basil B Sandberg Michael M Young Lucy H LH Miller Joan W JW Vavvas Demetrios G DG

The American journal of pathology 20120317 5

The increasing popularity of the Cre/loxP recombination system has led to the generation of numerous transgenic mouse lines in which Cre recombinase is expressed under the control of organ- or cell-specific promoters. Alterations in retinal pigment epithelium (RPE), a multifunctional cell monolayer that separates the retinal photoreceptors from the choroid, are prevalent in the pathogenesis of a number of ocular disorders, including age-related macular degeneration. To date, six transgenic mouse ...[more]

PMID: 22429967

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Project description:The presence of a phagocytic peak of photoreceptor outer segments by the retinal pigment epithelium (RPE) one or 2 h after the onset of light has been reported for several diurnal and nocturnal species. This peak in phagocytic activity also persists under constant lighting conditions (i.e., constant light or dark) thus demonstrating that the timing of this peak is driven by a circadian clock. The aim of this study was to investigate the change in RPE whole transcriptome at two different circadian times (CT; 1 h before (CT23) and 1 h after (CT1) subjective light onset). C57BL/6J male mice were maintained in constant dark conditions for three days and euthanized under red light (<1 lux) at CT23 and CT1. RPE was isolated from whole eyes for RNA library preparation and sequencing on an Illumina HiSeq4000 platform. 14,083 mouse RPE transcripts were detected in common between CT23 and CT1. 12,005 were protein coding transcripts and 2078 were non-protein coding transcripts. 2421 protein coding transcripts were significantly upregulated whereas only 3 transcripts were significantly downregulated and 12 non-protein coding transcripts were significantly upregulated and 31 non-protein coding transcripts were significantly downregulated at CT1 when compared to CT23 (p < 0.05, fold change ≥ ±2.0). Of the protein coding transcripts, most of them were characterized as: enzymes, kinases, and transcriptional regulators with a large majority of activity in the cytoplasm, nucleus, and plasma membrane. Non-protein coding transcripts included biotypes such as long-non coding RNAs and pseudogenes. Gene ontology analysis and ingenuity pathway analysis revealed that differentially expressed transcripts were associated with integrin signaling, oxidative phosphorylation, protein phosphorylation, and actin cytoskeleton remodeling suggesting that these previously identified phagocytic pathways are under circadian control. Our analysis identified new pathways (e.g., increased mitochondrial respiration via increased oxidative phosphorylation) that may be involved in the circadian control of phagocytic activity. In addition, our dataset suggests a possible regulatory role for the identified non-protein coding transcripts in mediating the complex function of RPE phagocytosis. Finally, our results also indicate, as seen in other tissues, about 20% of the whole RPE transcriptome may be under circadian clock regulation.

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Dataset Information

Evidence for baseline retinal pigment epithelium pathology in the Trp1-Cre mouse.

Publications

Evidence for baseline retinal pigment epithelium pathology in the Trp1-Cre mouse.

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