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Epigenome rejuvenation: HP1? mobility as a measure of pluripotent and senescent chromatin ground states.

ABSTRACT: We measured the dynamics of an essential epigenetic modifier, HP1?, in human cells at different stages of differentiation using Fluorescence Recovery After Photobleaching (FRAP). We found that HP1? mobility is similar in human embryonic stem cells (hES) and iPS cells where it is more mobile compared to fibroblasts; HP1? is less mobile in senescent fibroblasts than in young (dividing) fibroblasts. Introduction of "reprogramming factors", Oct4, Sox2, Klf4, cMyc and Lin28, into senescent fibroblasts and measuring the changes in HP1? mobility as reprogramming proceeds shows that the mobility of HP1? in senescent cells increases and by day 9 is the same as that found in young fibroblasts. Thus the dynamics of a key epigenetic modifier can be rejuvenated without de-differentiation through an embryonic stage. Future work will test whether other aspects of cellular physiology that age can be so rejuvenated without de-differentiation.

SUBMITTER: Manukyan M

PROVIDER: S-EPMC3999444 | biostudies-literature | 2014 Apr

REPOSITORIES: biostudies-literature

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Epigenome rejuvenation: HP1β mobility as a measure of pluripotent and senescent chromatin ground states.

Manukyan Maria M Singh Prim B PB

Scientific reports 20140425

We measured the dynamics of an essential epigenetic modifier, HP1β, in human cells at different stages of differentiation using Fluorescence Recovery After Photobleaching (FRAP). We found that HP1β mobility is similar in human embryonic stem cells (hES) and iPS cells where it is more mobile compared to fibroblasts; HP1β is less mobile in senescent fibroblasts than in young (dividing) fibroblasts. Introduction of "reprogramming factors", Oct4, Sox2, Klf4, cMyc and Lin28, into senescent fibroblast ...[more]

PMID: 24763337

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Project description:Pluripotent stem cell lines derived from embryos of different stages have distinct pluripotent ground states, but similar levels of the transcription factor Oct4. Epiblast-derived pluripotent stem cells (EpiSCs), in contrast to embryonic stem (ES) cells, cannot form chimeras. We show that EpiSCs express lower levels of the transcription factors Sox2 and Klf4 than ES cells and have limited reprogramming potential, as shown by cell fusion. Sox2 overexpression dramatically increases the reprogramming potential, chimera formation, and germline contribution of EpiSCs. Therefore, although Oct4 is essential for reprogramming, the level of Sox2 defines both the reprogramming capability and the pluripotent ground states. RNA samples to be analyzed on microarrays were prepared using Qiagen RNeasy columns with on-column DNA digestion. 300 ng of total RNA per sample was used as input into a linear amplification protocol (Ambion), which involved synthesis of T7-linked double-stranded cDNA and 12 hrs of in-vitro transcription incorporating biotin-labelled nucleotides. Purified and labelled cRNA was then hybridized for 18 hrs onto MouseRef-8 v2 expression BeadChips (Illumina) according to the manufacturer's instructions. After washing, as recommended, chips were stained with streptavidin-Cy3 (GE Healthcare) and scanned using the iScan reader (Illumina) and accompanying software. Samples were hybridized as biological replicates. 12 sample types were analyzed, each of them in duplicate. ESCm: Mouse ESC male; ESCf: Mouse ESC OG2 female; F9 EC: F9 EC (mouse embryonic carcinoma cell); F9-Sox2: F9 EC (mouse embryonic carcinoma cell) overexpressing wild type Sox2; EpiSCf: Mouse EpiSC OG2 female; Epi-Sox2f: Mouse EpiSC Sox2 (OG2 female) overexpressing wild type Sox2; P19 EC: P19 EC (mouse embryonic carcinoma cell); P19-Sox2: P19 EC (mouse embryonic carcinoma cell) overexpressing wild type Sox2; EpiSCm: Mouse EpiSC (GOF18 male) (duplicates); EpiSox2mL2: Mouse EpiSC Sox2 (GOF18 male) overexpressing wild type Sox2 cultured in condition EpiSC medium (CM); EpiSox2mE1: Mouse EpiSC Sox2 (GOF18 male) overexpressing wild type Sox2 cultured in ESC medium (ESC like1); EpiSox2mE2: Mouse EpiSC Sox2 (GOF18 male) overexpressing wild type Sox2 cultured in ESC medium (ESC like2).

Project description:AimThe aim is to assess the effects of CDCs on heart structure, function, gene expression, and systemic parameters in aged rats. Diastolic dysfunction is characteristic of aged hearts. Cardiosphere-derived cell (CDC) therapy has exhibited several favourable effects on heart structure and function in humans and in preclinical models; however, the effects of CDCs on aging have not been evaluated.Methods and resultsWe compared intra-cardiac injections of neonatal rat CDCs to vehicle (phosphate-buffered saline, PBS) in 21.8 ± 1.6 month-old rats (mean ± standard deviation; n = 23 total). Ten rats 4.1 ± 1.5 months of age comprised a young reference group. Blood, echocardiographic, haemodynamic and treadmill stress tests were performed at baseline in all animals, and 1 month after treatment in old animals. Histology and the transcriptome were assessed after terminal phenotyping. For in vitro studies, human heart progenitors from older donors, or cardiomyocytes from aged rats were exposed to human CDCs or exosomes secreted by CDCs (CDC-XO) from paediatric donors. Transcriptomic analysis revealed that CDCs, but not PBS, recapitulated a youthful pattern of gene expression in the hearts of old animals (85.5% of genes differentially expressed, P < 0.05). Telomeres in heart cells were longer in CDC-transplanted animals (P < 0.0001 vs. PBS). Cardiosphere-derived cells attenuated hypertrophy by echo (P < 0.01); histology confirmed decreases in cardiomyocyte area (P < 0.0001) and myocardial fibrosis (P < 0.05) vs. PBS. Cardiosphere-derived cell injection improved diastolic dysfunction [lower E/A (P < 0.01), E/E' (P = 0.05), end-diastolic pressure-volume relationship (P < 0.05) compared with baseline), and lowered serum brain natriuretic peptide (both P < 0.05 vs. PBS). In CDC-transplanted old rats, exercise capacity increased ∼20% (P < 0.05 vs. baseline), body weight decreased ∼30% less (P = 0.05 vs. PBS) and hair regrowth after shaving was more robust (P < 0.05 vs. PBS). Serum biomarkers of inflammation (IL-10, IL-1b, and IL-6) improved in the CDC group (P < 0.05 for each, all vs. PBS). Young CDCs secrete exosomes which increase telomerase activity, elongate telomere length, and reduce the number of senescent human heart cells in culture.ConclusionYoung CDCs rejuvenate old animals as gauged by cardiac gene expression, heart function, exercise capacity, and systemic biomarkers.

Dataset Information

Epigenome rejuvenation: HP1? mobility as a measure of pluripotent and senescent chromatin ground states.

Publications

Epigenome rejuvenation: HP1β mobility as a measure of pluripotent and senescent chromatin ground states.

Similar Datasets

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