Project description:Transcriptional profiling of reprogrammed cells at day 20 post-transduction comparing compact and differentiated colonies with established induced Pluripotent Stem Cells (iPSC) generated from human dermal fibroblasts (HDF). This study focused in the identification of upregulated transcription factors related to early developmental processes, particularly during primitive streak formation.
Project description:The variation among induced pluripotent stem cells (iPSCs) in their differentiation capacity to specific lineages is frequently attributed to somatic memory. In this study, we compared hematopoietic differentiation capacity of 35 human iPSC lines derived from four different tissues and four embryonic stem cell lines. The analysis revealed that hematopoietic commitment capacity (PSCs to hematopoietic precursors) is correlated with the expression level of the IGF2 gene independent of the iPSC origins. In contrast, maturation capacity (hematopoietic precursors to mature blood) is affected by iPSC origin; blood-derived iPSCs showed the highest capacity. However, some fibroblast-derived iPSCs showed higher capacity than blood-derived clones. Tracking of DNA methylation changes during reprogramming reveals that maturation capacity is highly associated with aberrant DNA methylation acquired during reprogramming, rather than the types of iPSC origins. These data demonstrated that variations in the hematopoietic differentiation capacity of iPSCs are not attributable to somatic memories of their origins. Methyl-seq analysis for undifferentiated induced pluripotent stem cell (iPSC) lines (n = 21), human dermal fibroblast (HDF, n = 1), human peripheral blood (n = 1), and human keratinocyte (n = 1), and ATAC-seq analysis for 2 iPSC lines and an embryonic stem cell (ESC) line with two different culture conditions. CTCF-ChIP-seq analysis for an ESC line.
Project description:Ageing is the gradual decline in organismal fitness that occurs over time leading to tissue dysfunction and disease. At the cellular level, ageing is associated with reduced function, altered gene expression and a perturbed epigenome. Somatic cell reprogramming, the process of converting somatic cells to induced pluripotent stem cells (iPSCs), can reverse these age-associated changes. However, during iPSC reprogramming somatic cell identity is lost, and can be difficult to reacquire as re-differentiated iPSCs often resemble foetal rather than mature adult cells. Recent work has demonstrated that the epigenome is already rejuvenated by the maturation phase of reprogramming, which suggests full iPSC reprogramming is not required to reverse ageing of somatic cells. Here we have developed the first “maturation phase transient reprogramming” (MPTR) method, where reprogramming factors are expressed until this rejuvenation point followed by withdrawal of their induction. Using dermal fibroblasts from middle age donors, we found that cells reacquire their fibroblast identity following MPTR, possibly as a result of persisting epigenetic memory at enhancers. Excitingly, our method substantially rejuvenated multiple cellular attributes including the transcriptome, which was rejuvenated by around 30 years as measured by a novel transcriptome clock. The epigenome, including H3K9me3 histone methylation levels and the DNA methylation ageing clock, was rejuvenated to a similar extent. MPTR fibroblasts produced youthful levels of collagen proteins, suggesting functional rejuvenation. Overall, our work demonstrates that it is possible to separate rejuvenation from pluripotency reprogramming, which should facilitate the discovery of novel anti-ageing genes and therapies.
Project description:Ageing is the gradual decline in organismal fitness that occurs over time leading to tissue dysfunction and disease. At the cellular level, ageing is associated with reduced function, altered gene expression and a perturbed epigenome. Somatic cell reprogramming, the process of converting somatic cells to induced pluripotent stem cells (iPSCs), can reverse these age-associated changes. However, during iPSC reprogramming somatic cell identity is lost, and can be difficult to reacquire as re-differentiated iPSCs often resemble foetal rather than mature adult cells. Recent work has demonstrated that the epigenome is already rejuvenated by the maturation phase of reprogramming, which suggests full iPSC reprogramming is not required to reverse ageing of somatic cells. Here we have developed the first “maturation phase transient reprogramming” (MPTR) method, where reprogramming factors are expressed until this rejuvenation point followed by withdrawal of their induction. Using dermal fibroblasts from middle age donors, we found that cells reacquire their fibroblast identity following MPTR, possibly as a result of persisting epigenetic memory at enhancers. Excitingly, our method substantially rejuvenated multiple cellular attributes including the transcriptome, which was rejuvenated by around 30 years as measured by a novel transcriptome clock. The epigenome, including H3K9me3 histone methylation levels and the DNA methylation ageing clock, was rejuvenated to a similar extent. MPTR fibroblasts produced youthful levels of collagen proteins, suggesting functional rejuvenation. Overall, our work demonstrates that it is possible to separate rejuvenation from pluripotency reprogramming, which should facilitate the discovery of novel anti-ageing genes and therapies.
Project description:Ageing is the gradual decline in organismal fitness that occurs over time leading to tissue dysfunction and disease. At the cellular level, ageing is associated with reduced function, altered gene expression and a perturbed epigenome. Somatic cell reprogramming, the process of converting somatic cells to induced pluripotent stem cells (iPSCs), can reverse these age-associated changes. However, during iPSC reprogramming somatic cell identity is lost, and can be difficult to reacquire as re-differentiated iPSCs often resemble foetal rather than mature adult cells. Recent work has demonstrated that the epigenome is already rejuvenated by the maturation phase of reprogramming, which suggests full iPSC reprogramming is not required to reverse ageing of somatic cells. Here we have developed the first “maturation phase transient reprogramming” (MPTR) method, where reprogramming factors are expressed until this rejuvenation point followed by withdrawal of their induction. Using dermal fibroblasts from middle age donors, we found that cells reacquire their fibroblast identity following MPTR, possibly as a result of persisting epigenetic memory at enhancers. Excitingly, our method substantially rejuvenated multiple cellular attributes including the transcriptome, which was rejuvenated by around 30 years as measured by a novel transcriptome clock. The epigenome, including H3K9me3 histone methylation levels and the DNA methylation ageing clock, was rejuvenated to a similar extent. MPTR fibroblasts produced youthful levels of collagen proteins, suggesting functional rejuvenation. Overall, our work demonstrates that it is possible to separate rejuvenation from pluripotency reprogramming, which should facilitate the discovery of novel anti-ageing genes and therapies.
Project description:Ageing is the gradual decline in organismal fitness that occurs over time leading to tissue dysfunction and disease. At the cellular level, ageing is associated with reduced function, altered gene expression and a perturbed epigenome. Somatic cell reprogramming, the process of converting somatic cells to induced pluripotent stem cells (iPSCs), can reverse these age-associated changes. However, during iPSC reprogramming somatic cell identity is lost, and can be difficult to reacquire as re-differentiated iPSCs often resemble foetal rather than mature adult cells. Recent work has demonstrated that the epigenome is already rejuvenated by the maturation phase of reprogramming, which suggests full iPSC reprogramming is not required to reverse ageing of somatic cells. Here we have developed the first “maturation phase transient reprogramming” (MPTR) method, where reprogramming factors are expressed until this rejuvenation point followed by withdrawal of their induction. Using dermal fibroblasts from middle age donors, we found that cells reacquire their fibroblast identity following MPTR, possibly as a result of persisting epigenetic memory at enhancers. Excitingly, our method substantially rejuvenated multiple cellular attributes including the transcriptome, which was rejuvenated by around 30 years as measured by a novel transcriptome clock. The epigenome, including H3K9me3 histone methylation levels and the DNA methylation ageing clock, was rejuvenated to a similar extent. MPTR fibroblasts produced youthful levels of collagen proteins, suggesting functional rejuvenation. Overall, our work demonstrates that it is possible to separate rejuvenation from pluripotency reprogramming, which should facilitate the discovery of novel anti-ageing genes and therapies.
Project description:The variation among induced pluripotent stem cells (iPSCs) in their differentiation capacity to specific lineages is frequently attributed to somatic memory. In this study, we compared hematopoietic differentiation capacity of 35 human iPSC lines derived from four different tissues and four embryonic stem cell lines. The analysis revealed that hematopoietic commitment capacity (PSCs to hematopoietic precursors) is correlated with the expression level of the IGF2 gene independent of the iPSC origins. In contrast, maturation capacity (hematopoietic precursors to mature blood) is affected by iPSC origin; blood-derived iPSCs showed the highest capacity. However, some fibroblast-derived iPSCs showed higher capacity than blood-derived clones. Tracking of DNA methylation changes during reprogramming reveals that maturation capacity is highly associated with aberrant DNA methylation acquired during reprogramming, rather than the types of iPSC origins. These data demonstrated that variations in the hematopoietic differentiation capacity of iPSCs are not attributable to somatic memories of their origins. Bisulfite-converted genomic DNA lysates from human induced pluripotent stem cells derived from dermal fibroblasts, peripheral T cells, cord blood, and dental pulp cells were hybridized to the Illumina HumanMethylation450 BeadChip.
Project description:Induced cellular reprogramming to the pluripotent state offers a novel stem cell source for autologous transplantation. While recent studies have explored the role of factors required for induced pluripotent stem cell (iPSC) induction, the cellular and molecular basis of reprogramming from human fibroblasts remains elusive. Here, we have identified a subset of human dermal-derived fibroblasts that shares hallmark molecular and epigenetic features with pluripotent cells. Functional studies demonstrate that these cells contribute to the majority of human iPSCs generated from dermal fibroblasts and are dependent on heterogeneous fibroblast microenvironment for reprogramming competency. Molecular characterization indicated these predisposed fibroblasts were unique to other dermal derived stem cells and possessed features of proliferative selfrenewal. Our study reveals human fibroblasts are not equivalently capable of cellular reprogramming, and suggests that reprogramming factors overcome commitment steps that allow predetermined dermal fibroblasts to establish stable pluripotent state.
Project description:Patient-derived cells hold great promise for precision medicine approaches in human health. Fibroblast cells have been a major source of human cells for reprogramming and differentiating into specific cell types for disease modeling. Such cells can be isolated at various stages during life (presymptomatic, symptomatic, and advanced disease) and thus can potentially be used to model different phases of disease progression. In certain circumstances, however, tissues are not collected during life and only postmortem tissues are the only available source of fibroblasts. Fibroblasts cultured from postmortem human dura mater of individuals with neurodegenerative diseases have been suggested as a primary source of cells for in vitro modeling of neurodegenerative diseases. Although fibroblast-like cells from human and mouse dura mater have been previously described, their utility for reprogramming and direct differentiation protocols requires further characterization. In this study, cells derived from dermal biopsies of living subjects were compared to cells derived from postmortem dura mater. In two instances, we have isolated and compared dermal and dural cell lines from the same subject. Notably, such striking differences were observed between cells of dermal and dural origin that their fibroblast nature was brought into question. Compared to dermal fibroblasts, postmortem dura mater-derived cells demonstrated different morphology, slower growth rates, and a higher rate of karyotype abnormality. Dura mater-derived cells also failed to express fibroblast protein markers. When dermal fibroblasts and dural-derived cells from the same subject were compared, they exhibited significant differences in gene expression profiles. Ultimately, dura mater-derived cells were found to originate from a mixed mural lineage consisting of smooth muscle cells and pericytes. Our study argues for rigorous karyotyping of all postmortem derived cell lines and highlights significant limitations of postmortem human dura mater-derived cells for modeling normal biology or disease-associated pathobiology.
Project description:Detection of senescence-associated miRNAs differentially transcribed during early (D7) and late stages (D21) of human dermal fibroblast (HDF) senescence