Project description:Ageing causes a progressive deterioration of the structure and function of vascular cells that results in a decline of vascular functionality. Impaired functionality of vascular cells is a key factor that triggers several age-related vascular diseases. Most of our understanding of this process comes from in vitro studies. Further understanding of the mechanism underlying vascular aging in vivo are needed to get new insights into the pathobiology of age-associated vascular diseases. Here we use a combination of transcriptomics, immunostaining, and in vivo pharmacological and regeneration assays coupled with the extracorporeal vasculature of the invertebrate chordate Botryllus schlosseri (which is large, transparent, accessible and easy to manipulate) and show that we can study morphological, transcriptional and functional age-associated changes of vascular cells that are similar to those of mammalian vascular cells from tissue culture and fixed vascular cells. We showed that age-associated changes in the cytoskeleton and the ECM reshape vascular cells into flatten and elongated form and heavily accumulate Collagen, rendering the vessels into more rigid and less responsive to pharmacological insults. These changes did not alter the regeneration potential of aged blood vessels and newly regenerated vascular cells retained the same aged phenotype. Furthermore, we found that a subset of blood circulating hemocytes showed reduced proliferation while increasing apoptosis in aged animals.
Project description:Background: Gonad differentiation is an essential function for all sexually reproducing species, and many aspects of these developmental processes are highly conserved among the metazoa. The colonial ascidian, Botryllus schlosseri is a chordate model organism which offers two unique traits that can be utilized to characterize the genes underlying germline development: a colonial life history and variable fertility. These properties allow individual genotypes to be isolated at different stages of fertility and gene expression can be characterized comprehensively. Results: Here we characterized the transcriptome of both fertile and infertile colonies throughout blastogenesis (asexual development) using differential expression analysis. We identified genes (as few as 7 and as many as 647) regulating fertility in Botryllus at each stage of blastogenesis. Several of these genes appear to drive gonad maturation, as they are expressed by follicle cells surrounding both testis and oocyte precursors. Spatial and temporal expression of differentially expressed genes was analyzed by in situ hybridization, confirming expression in developing gonads. Conclusion: We have identified several genes expressed in developing and mature gonads in B. schlosseri. Analysis of genes upregulated in fertile animals suggests a high level of conservation of the mechanisms regulating fertility between basal chordates and vertebrates. mRNA profiles of seven infertile stages from infertile Botryllus schlosseri colonies (each in triplicates) and seven stages of fertile Botryllus schlosseri colonies (each in triplicates) using Illumina deep sequencing and analyzed for differential expression between each stage.
Project description:Background: Gonad differentiation is an essential function for all sexually reproducing species, and many aspects of these developmental processes are highly conserved among the metazoa. The colonial ascidian, Botryllus schlosseri is a chordate model organism which offers two unique traits that can be utilized to characterize the genes underlying germline development: a colonial life history and variable fertility. These properties allow individual genotypes to be isolated at different stages of fertility and gene expression can be characterized comprehensively. Results: Here we characterized the transcriptome of both fertile and infertile colonies throughout blastogenesis (asexual development) using differential expression analysis. We identified genes (as few as 7 and as many as 647) regulating fertility in Botryllus at each stage of blastogenesis. Several of these genes appear to drive gonad maturation, as they are expressed by follicle cells surrounding both testis and oocyte precursors. Spatial and temporal expression of differentially expressed genes was analyzed by in situ hybridization, confirming expression in developing gonads. Conclusion: We have identified several genes expressed in developing and mature gonads in B. schlosseri. Analysis of genes upregulated in fertile animals suggests a high level of conservation of the mechanisms regulating fertility between basal chordates and vertebrates.