Project description:The transcriptome of hMSC in late passages was compared to hMSC in early passages. Both hMSC were obtained from the umbilical vein of three donors, two of hMSC have a normal karyotype (MSC/n) and another has a constitutional paracentric chromosomal inversion (hMSC/inv).
Project description:Hutchinson-Gilford progeria syndrome (HGPS) is a rare and fatal human premature aging disease1-5, characterized by premature atherosclerosis and degeneration of vascular smooth muscle cells (SMCs)6-8. HGPS is caused by a single-point mutation in the LMNA gene, resulting in the generation of progerin, a truncated mutant of lamin A. Accumulation of progerin leads to various aging-associated nuclear defects including disorganization of nuclear lamina and loss of heterochromatin9-12. Here, we report the generation of induced pluripotent stem cells (iPSCs) from fibroblasts obtained from patients with HGPS. HGPS-iPSCs show absence of progerin, and more importantly, lack the nuclear envelope and epigenetic alterations normally associated with premature aging. Upon differentiation of HGPS-iPSCs, progerin and its associated aging consequences are restored. In particular, directed differentiation of HGPS-iPSCs to SMCs leads to the appearance of premature senescent SMC phenotypes associated with vascular aging. Additionally, our studies identify DNA-dependent protein kinase catalytic subunit (DNAPKcs) as a component of the progerin-containing protein complex. The absence of nuclear DNAPKcs correlates with premature as well as physiological aging. Since progerin also accumulates during physiological aging6,12,13, our results provide an in vitro iPSC-based model with an acceleration progerin accumulation to study the pathogenesis of human premature and physiological vascular aging. Microarray gene expression profiling was done to: (1) Compare differences between WT fibroblasts and fibroblasts from patients suffering of the Hutchinson-Gilford progeria syndrome (2) Check that iPSC originating from WT and patients are in fact similar to ESC
Project description:The presence of senescent cells in the aging/degenerating human disc is now well-recognized. Senescent cells are viable, cannot divide, remain metabolically active and accumulate within the disc over time. Molecular analysis of senescent cells in tissue, however, offers a special challenge since there are no cell surface markers for senescence which would let one use fluorescence-activated cell sorting as a method for separating out senescent cells. Here we use a novel experimental design using laser capture microdissection to selectively separately harvest senescent and non-senescent annulus cells in paraffin-embedded tissue, and then compare their gene expression with microarray analysis. An initial in vitro study using cultured human annulus cells was first performed to test whether there was any difference in identification of senescent cells using the accepted histochemical methodology vs. the immunofluoresent identification of cells positive for senescence-associated-ß-galactosidase in control cells and cells induced into stress-induced premature senescence via hydrogen peroxide exposure. No statistically significant difference was found between the 2 methods. Laser capture microdissection was used to separately harvest senescent and non-senescent cells from 11 human annulus specimens, and microarray analysis was used to determine gene expression levels. Genes with established relationships to senescence were found to be significantly upregulated in senescent cells vs. non-senescent cells. Additional genes related to cytokines, cell proliferation, and other cell processes were also identified. Disc Tissue samples were obtained from surgical disc procedures performed on patients with herniated discs and degenerative disc disease. Tissue was fixed and paraffin embedded. Standard laser capture microdissection (LCM) techniques were used to collect senescent cells. Remaining non-senescent cells were scraped from the histology slide. Total RNA was isolated and analyzed via mircoarray. Gene expression from senescent cells was compared to non-senescent cells. Eight histological samples were used to obtain both senescent and non-senescent cells. From an additional 3 samples, only senescent cells were harvested.
Project description:We aimed in this study to identify the differentially regulated genes by Dlk1 in hMSC cells using microarray technology in order to gain a better understanding of Dlk1-mediated signaling pathways during hMSC differentiation. Both control (hMSC-TERT)(not expressing Dlk1) and Dlk1 overexpressing cells (hMSC-Dlk1) were cultured in triplicate at 3×104 cells/cm2 in Petri-dish in standard growth medium. At 90-100% confluence, highly purified total cellular RNA was isolated from each of three independent cultures per cell line using RNeasy Kit (QIAGEN Nordic, West Sussex, UK) according to the manufacturer?s instructions
Project description:DamID LaminB1 data were generated in POU2F1-/- MEFs to study the potential role of POU2F1/Oct1 in genome - nuclear lamina interactions. DamID LaminA data were generated in NPCs and Astrocytes to study similarities/differences between LaminA and LaminB1 binding. Comparison of MEF wt versus MEF POU2F1-/-. Comparison of LaminA (NPC & AC) with LaminB1 (NPC & AC data in GSE17051)
Project description:Quiescent (Q) and stress induced premature senescent (SIPS) fibroblasts were treated for the duration of 4 days with growth medium supplemented with a plant extract (1201) from Solidago vigaurea subspecies alpestris. Rna was isolated with Trizol and sent to GATC for next generation sequencing with Ilumina technology. The plant extract proofed to block the negative effects of senescence in human skin fibroblasts in various experiments by delaying the acquisition of a senescent phenotype/favouring a papillary-like phenotype and attenuating the senescence associated secretory phenotype. The RNAseq was performed to understand the underlying molecular mechanism of the observed effects. SIPS was induced by chronic oxidative stress treatment (9 days with 1 h 100 µM H2O2 per day).
Project description:Differentiation of human skeletal stem cells (hMSC) into osteoblasts is regulated by a few well described transcription factors. Our study used clustering and gene expression data to identify a novel transcription factor. ZNF25, which we showed is involved in osteoblast differentiation. We used microarrays to study gene expression of hMSC-TERT4 cells after siZNF25 knockdown. hMSC-TERT4 cells were sampled as undifferentiated hMSC and as differentiated osteoblasts.
Project description:Comparison between extracellular vesicles produced from 2D-cultured human Mesenchymal Stem Cells (hMSC) in starvation, and extracellular vesicles produced from spheroids of hMSC hydrodynamically stimulated in a cross-slot millifluidic chip.
Project description:The presence of senescent cells in the aging/degenerating human disc is now well-recognized. Senescent cells are viable, cannot divide, remain metabolically active and accumulate within the disc over time. Molecular analysis of senescent cells in tissue, however, offers a special challenge since there are no cell surface markers for senescence which would let one use fluorescence-activated cell sorting as a method for separating out senescent cells. Here we use a novel experimental design using laser capture microdissection to selectively separately harvest senescent and non-senescent annulus cells in paraffin-embedded tissue, and then compare their gene expression with microarray analysis. An initial in vitro study using cultured human annulus cells was first performed to test whether there was any difference in identification of senescent cells using the accepted histochemical methodology vs. the immunofluoresent identification of cells positive for senescence-associated-ß-galactosidase in control cells and cells induced into stress-induced premature senescence via hydrogen peroxide exposure. No statistically significant difference was found between the 2 methods. Laser capture microdissection was used to separately harvest senescent and non-senescent cells from 11 human annulus specimens, and microarray analysis was used to determine gene expression levels. Genes with established relationships to senescence were found to be significantly upregulated in senescent cells vs. non-senescent cells. Additional genes related to cytokines, cell proliferation, and other cell processes were also identified.
Project description:Adult human mesenchymal stem cells (hMSCs) have shown promise as a valuable new therapeutic tool in a wide range of diseases. hMSCs from bone marrow stroma are currently isolated by their adherence to tissue culture treated polystyrene (TCP) and passaged multiple times on the same plastics until they are able to produce enough cells to be useful for research or clinical therapeutic trials. However, evidence in the literature has shown that culture on TCP can negatively alter hMSC function. Our aim was to expand hMSCs in an in vitro environment more closely resembling that of the hMSCs' native microenvironment to maximize proliferation while retaining therapeutic potential. We used decellularized hMSC-derived extracellular matrix (hMSC-ECM) to test hMSCs' maintenance of stem cell properties during in vitro expansion. We found that hMSC-ECM was able to increase hMSC proliferation while retaining the stem cells‘ immature state and increasing differentiation potential. In addition, the hMSC-ECM could be covalently cross-linked to polymer substrates and was effective in the isolation and expansion of hMSCs in the presence of fetal bovine serum and human serum. Using proteomics and transcriptomics, we were able to determine the mechanism behind the hMSCs’ increased proliferation was due to their ability to downregulate their otherwise required gene expression for ECM proteins by on hMSC-ECM. The effects of hMSC-ECM were largely hMSC specific and were not found with several other types of human cells. Providing a pre-formed in vitro niche for hMSCs can provide the cells with the critical components required for hMSC function during in vitro expansion.