Project description:Regeneration of skeletal muscle depends on a population of adult stem cells (satellite cells) that remain quiescent throughout life. Satellite cell regenerative functions decline with aging. Here we report that geriatric satellite cells, compared to old cells, are incapable of maintaining their normal quiescent state in muscle homeostatic conditions, and this irreversibly affects their intrinsic regenerative and self-renewal capacities. We analyzed the global changes in gene expression occurring within muscle stem cells (satellite cells) in homeostatic conditions during physiological aging. Pure satellite cell populations from dissociated skeletal muscle from Young (2-3 months) and Geriatric (28-32 months) mice were isolated using a well-established flow cytometry protocol gating on integrin a7(+)/CD34(+) (positive selection) and Lin- (CD31, CD45, CD11b, Sca1) (negative selection).
Project description:Regeneration of skeletal muscle depends on a population of adult stem cells (satellite cells) that remain quiescent throughout life. Satellite cell regenerative functions decline in geriatric satellite cells, compared to old cells are incapable of maintaining their normal quiescent state in muscle homeostatic conditions, and this irreversibly affects their intrinsic regenerative and self-renewal capacities. In geriatric mice, resting satellite cells lose reversible quiescence by switching to an irreversible pre-senescence state, caused by derepression of p16INK4a. Young Bmi1-deficient satellite cells shares similar features. We analyzed the global changes in gene expression occurring within muscle stem cells (satellite cells) in homeostatic conditions during physiological aging. Pure satellite cell populations from dissociated skeletal muscle from WT and Bmi1-deficient mice were isolated using a well-established flow cytometry protocol gating on integrin a7(+)/CD34(+) (positive selection) and Lin- (CD31, CD45, CD11b, Sca1) (negative selection).
Project description:Regeneration of skeletal muscle depends on a population of adult stem cells (satellite cells) that remain quiescent throughout life. Satellite cell regenerative functions decline with aging and in progeric conditions. Here we report that geriatric satellite cells, compared to old cells, are incapable of maintaining their normal quiescent state in muscle homeostatic conditions, and this irreversibly affects their intrinsic regenerative and self-renewal capacities. We analyzed the global changes in gene expression occurring within muscle stem cells (satellite cells) in homeostatic conditions during physiological aging and progeria. Pure satellite cell populations from dissociated skeletal muscle from Young (2-3 months), Old (22-24 months), Geriatric (28-30 months), SAMR1 and SAMP8 mice were isolated using a well-established flow cytometry protocol gating on integrin a7(+)/CD34(+) (positive selection) and Lin- (CD31, CD45, CD11b, Sca1) (negative selection).
Project description:Regeneration of skeletal muscle depends on a population of adult stem cells (satellite cells) that remain quiescent throughout life. Satellite cell regenerative functions decline with aging. We report that geriatric satellite cells, compared to old and adult cells, are incapable of maintaining their normal quiescent state in muscle homeostatic conditions, and this irreversibly affects their intrinsic regenerative and self-renewal capacities. We analyzed the global changes in gene expression occurring within muscle stem cells (satellite cells) in homeostatic conditions during physiological aging. Pure satellite cell populations from dissociated skeletal muscle from Young (2-3 months) and Adult (6 months) mice were isolated using a well-established flow cytometry protocol gating on integrin a7(+)/CD34(+) (positive selection) and Lin- (CD31, CD45, CD11b, Sca1) (negative selection).
Project description:We performed genome-wide gene expression analysis of quiescent/activated muscle stem cells isolated from mouse skeletal muscle by flow cytometry. We analyzed the global changes in gene expression occurring within muscle stem cells (satellite cells) in homeostatic conditions or after cardiotoxin (CTX) injury (3 days). Pure satellite cell populations from dissociated skeletal muscle from mice were isolated using a well-established flow cytometry protocol gating on integrin a7(+) (positive selection) and Lin- (CD31, CD45, CD11b, Sca1) (negative selection).
Project description:Preservation of cell identity is necessary for homeostasis of most adult tissues. This process is challenged every time a tissue undergoes regeneration after stress or injury. In the lethal Duchenne muscular Dystrophy (DMD), skeletal muscle regenerative capacity declines gradually as fibrosis increases. Using genetically engineered-tracing mice, we demonstrate that in dystrophic muscle, specialized cells of muscular, endothelial and hematopoietic origins gain plasticity towards a fibrogenic fate via a TGFβ-mediated pathway. This results in loss of cellular identity and normal function, with deleterious consequences for regeneration. Furthermore, this fibrogenic process involves acquisition of a mesenchymal progenitor multipotent status, illustrating a link between fibrogenesis and gain of progenitor cell functions. As this plasticity was also observed in DMD patients, we propose that mesenchymal transitions impair regeneration and worsen diseases with a fibrotic component. TGFb exposure induced gene expression was measured after 4 days of treatment compared to untreated cells. Three independent experiments were performed both for the treatment and for the control
Project description:The Outer Subventricular Zone (OSVZ) is a germinal layer playing key roles in the development of the neocortex, with particular relevance in gyrencephalic species like human and ferret where it contains abundant basal Radial Glia Cells (bRGCs) that promote cortical expansion. Here we identify a brief period in ferret embryonic development when apical RGCs generate a burst of bRGCs that become founders of the OSVZ. After this period, bRGCs in the OSVZ proliferate and self-renew exclusively locally, thereby forming a self-sustained lineage independent from the other germinal layers. The time window for the brief period of OSVZ bRGC production is delineated by the coincident down-regulation of Cdh1 and Trnp1, and their up-regulation reduces bRGC production and prevents OSVZ seeding. This mechanism in cortical development may have key relevance in brain evolution and disease Samples were analyzed with 3 replicates of each of them (except E34SVZ that has 2 replicantes). Comparisons were done taking different reference sample depending on the comparison.
Project description:A major challenge in Down syndrome (DS) is to understand how the extra-dose of functional chromosome 21 (HSA21) genetic elements can impact on the tissue-specific transcriptome to contribute to phenotypic alterations. MiRNAs are post-transcriptional modulators with genome-wide regulatory effects. Five microRNAs have been identified in HSA21 that are present in triple copy in DS individuals. Interestingly, in the Ts65Dn mouse model of DS two of these miRNAs, miR-155 and miR-802, are also triplicated resulting in its overexpression. In the current work, we have developed a lentiviral miRNA-sponge genetic strategy for miR-155 and miR-802 (Lv-miR155-802T) to identify novel mRNA targets involved in hippocampal function. Hippocampal injection of the lentiviral sponge in Ts65Dn mice reduced miR-155 and miR-802 overexpression. Noticeable lentiviral sponge rescued the expression of the miRNA predicted targets showing the potential of the strategy to identify miRNA dosage-sensitive genes with potential involvement in DS-hippocampal phenotypes. Euploid and trisomic adult mice were bilaterally injected at the level of the ventral hippocampus at selected coordinates (AP=-3.3mm, L=+/- 3mm, DV=-3.3mm and -2.3mm relative to bregma). Up to 108 transducing units (3µl of viral suspensions of Lv-Contol or Lv-miR155-802T) were injected into each hemisphere at a rate of 0.2 µl/min, under the precise control of an infusion pump (Ultramicropump, World Precision Instruments). Mice were euthanized for hippocampus collection at day 23 after administration. Transcriptome of hippocampus of euploid and trisomic mice treated with Lv-Control or Lv-miR155-802T was analysed using an Agilent SurePrint G3 Mouse gene expression 8x60K Microarray (ID 028005). A total RNA 100 ng, obtained using miRNeasy Mini Ki (QIAGEN), were labeled using LowInputQuick Amp Labeling kit (Agilent 5190-2305) following manufacturer instructions. Briefly, mRNA was reverse transcribed in the presence of T7-oligo-dT primer to produce cDNA. cDNA was then in vitro transcribed with T7 RNA polymerase in the presence of Cy3-CTP to produce labeled cRNA. The labeled cRNA was hybridized to the Agilent SurePrint G3 Mouse gene expression 8x60K Microarray (ID 028005) according to the manufacturer's protocol. The arrays were washed, and scanned on an Agilent G2565CA microarray scanner at 100% PMT and 3µm resolution. Intensity data was extracted using the Feature Extraction software (Agilent). Replicates from each genotypes and treatment group were distributed as follows: EU+Lv-Contol n=4, EU+Lv-miR155-802T n=4, TS+Lv-Contol n=5, TS+Lv-miR155-802T n=3.
Project description:Mouse models of intestinal crypt cell differentiation and tumorigenesis have been used to characterize the molecular mechanisms underlying both processes. DNA methylation is a key epigenetic mark and plays an important role in cell identity and differentiation programs and cancer. To get insights into the dynamics of cell differentiation and malignant transformation we have compared the DNA methylation profiles along the mouse small intestine crypt and early stages of carcinogenesis. Genome-scale analysis of DNA methylation together with microarray gene expression have been applied to compare intestinal crypt stem cells (EphB2positive), differentiated cells (EphB2negative), ApcMin/+ adenomas and the corresponding non-tumor adjacent tissue, together with small and large intestine samples and the colon cancer cell line CT26. Compared with late stages, small intestine crypt differentiation and early stages of carcinogenesis display few and relatively small changes in DNA methylation. Hypermethylated loci are largely shared by the two processes and affect the proximities of promoter and enhancer regions, with enrichment in genes regulated by PRC2 and associated with the intestinal stem cell signature. The hypermethylation is progressive, with minute levels in differentiated cells, as compared with intestinal stem cells, and reaching full methylation in advanced stages. Hypomethylation shows different signatures in differentiation and cancer and is already present in the non-tumor tissue adjacent to the adenomas in ApcMin/+mice, but at lower levels than advanced cancers. Taking into account the parallelisms between human and mouse intestinal carcinogenesis, this study provides a reference framework to interpret the alterations found in human cancer. We have analyzed ApcMin/+ adenomas and the corresponding non-tumor adjacent tissue, together with small and large intestine samples and the colon cancer cell line CT26. Samples were in triplicates, except for tissue adjacent to adenoma (in duplicates).
Project description:Our work aims to characterize the role of Zrf1 in the generation and maintenance of neural progenitor cells (NPCs) Gene expression profile of shCtrl and shZrf1 cells during generation of RGC-like NPC from ESC at day 6 of neural induction. Cells were grown according to this protocol: Bibel et al, Nat Prot., 2007