Deciphering the complexities of human diseases and disorders by coupling induced-pluripotent stem cells and systems genetics

Department of Regenerative Medicine, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.
Wiley Interdisciplinary Reviews Systems Biology and Medicine (Impact Factor: 3.21). 07/2012; 4(4):339-50. DOI: 10.1002/wsbm.1170
Source: PubMed


The recent discovery that adult mouse and human somatic cells can be ‘reprogrammed’ to a state of pluripotency by ectopic expression of only a few transcription factors has already made a major impact on the biomedical community. For the first time, it is possible to study diseases on an individual patient basis, which may eventually lead to the realization of personalized medicine. The utility of induced-pluripotent stem cells (iPSCs) for modeling human diseases has greatly benefitted from established human embryonic stem cell (ESC) differentiation and tissue engineering protocols developed to generate many different cell and tissue types. The limited access to preimplantation genetic tested embryos and the difficulty in gene targeting human ESCs have restricted the use of human ESCs in modeling human disease. Afforded by iPSC technology is the ability to study disease pathogenesis as it unfolds during tissue morphogenesis. The complexities of molecular signaling and interplay with protein transduction during disease progression necessitate a systems approach to studying human diseases, whereby data can be statistically integrated by sorting out the signal to noise issues that arise from global biological changes associated with disease versus experimental noise. Using a systems approach, biomarkers can be identified that define the initiation or progression of disease and likewise can serve as putative therapeutic targets. WIREs Syst Biol Med 2012 doi: 10.1002/wsbm.1170
For further resources related to this article, please visit the WIREs website.

Download full-text


Available from: William L Stanford,
  • Source
    • "The recent discovery of iPSCs provides a potential alternative cell source for cell therapies and regenerative medicine (Takahashi and Yamanaka, 2006; Takahashi et al., 2007). However, a more immediate impact of iPSCs is its application to modeling human diseases and disorders (Chang et al., 2012; Grskovic et al., 2011); for example, iPSCs derived from patients harboring genetic perturbations that result in premature atherosclerosis can be used to screen for novel antiatherosclerosis therapies. Since the initial demonstration of somatic reprogramming to a pluripotent state by the exogenous expression of Oct4, Sox2, Klf4, and c-Myc in dermal fibroblasts (Takahashi et al., 2007), numerous additional somatic cell types have been reprogrammed into iPSCs including neural progenitors (Eminli et al., 2008), B-cells (Choi et al., 2011), T-cells (Brown et al., 2010; Loh et al., 2010; Seki et al., 2010), adipocytes (Sun et al., 2009), and endothelial cells (Ho et al., 2010). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Induced-pluripotent stem cells (iPSCs) are a potential alternative cell source in regenerative medicine, which includes the use of differentiated iPSCs for cell therapies to treat coronary artery and/or peripheral arterial diseases. Late-outgrowth endothelial progenitor cells (late-EPCs) are a unique primary cell present in peripheral blood that exhibit high proliferative capacity, are being used in a wide variety of clinical trials, and have the ability to differentiate into mature endothelial cells. The objective of this study was to reprogram peripheral blood-derived late-EPCs to a pluripotent state under feeder-free and defined culture conditions. Late-EPCs that were retrovirally transduced with OCT4, SOX2, KLF4, c-MYC, and iPSC colonies were derived in feeder-free and defined media conditions. EPC-iPSCs expressed pluripotent markers, were capable of differentiating to cells from all three germ-layers, and retained a normal karyotype. Transcriptome analyses demonstrated that EPC-iPSCs exhibit a global gene expression profile similar to human embryonic stem cells (hESCs). We have generated iPSCs from late-EPCs under feeder-free conditions. Thus, peripheral blood-derived late-outgrowth EPCs represent an alternative cell source for generating iPSCs.
    Stem Cell Research 12/2012; 10(2):195-202. DOI:10.1016/j.scr.2012.11.006 · 3.69 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Elastin haploinsufficiency in Williams-Beuren syndrome (WBS) leads to increased vascular smooth muscle cell (SMC) proliferation and stenoses. Our objective was to generate a human induced pluripotent stem (hiPS) cell model for in vitro assessment of the WBS phenotype and to test the ability of candidate agents to rescue the phenotype. hiPS cells were reprogrammed from skin fibroblasts of a WBS patient with aortic and pulmonary stenosis and healthy control BJ fibroblasts using four-factor retrovirus reprogramming and were differentiated into SMCs. Differentiated SMCs were treated with synthetic elastin-binding protein ligand 2 (EBPL2) (20 μ g/ml) or the antiproliferative drug rapamycin (100 nM) for 5 days. We generated four WBS induced pluripotent stem (iPS) cell lines that expressed pluripotency genes and differentiated into all three germ layers. Directed differentiation of BJ iPS cells yielded an 85%-92% pure SMC population that expressed differentiated SMC markers, were functionally contractile, and formed tube-like structures on three-dimensional gel assay. Unlike BJ iPS cells, WBS iPS cells generated immature SMCs that were highly proliferative, showed lower expression of differentiated SMC markers, reduced response to the vasoactive agonists, carbachol and endothelin-1, impaired vascular tube formation, and reduced calcium flux. EBPL2 partially rescued and rapamycin fully rescued the abnormal SMC phenotype by decreasing the smooth muscle proliferation rate and enhancing differentiation and tube formation. WBS iPS cell-derived SMCs demonstrate an immature proliferative phenotype with reduced functional and contractile properties, thereby recapitulating the human disease phenotype. The ability of rapamycin to rescue the phenotype provides an attractive therapeutic candidate for patients with WBS and vascular stenoses.
    STEM CELLS TRANSLATIONAL MEDICINE 12/2012; 2(1). DOI:10.5966/sctm.2012-0054 · 5.71 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The advent of induced pluripotent stem cells (iPSCs) 1 revolutionized Human Genetics by allowing us to generate pluripotent cells from easily accessible somatic tissues. This technology can have immense implications for regenerative medicine, but iPSCs also represent a paradigm shift in the study of complex human phenotypes, including gene regulation and disease 2-5. Yet, an unresolved caveat of the iPSC model system is the extent to which reprogrammed iPSCs retain residual phenotypes from their precursor somatic cells. To directly address this issue, we used an effective study design to compare regulatory phenotypes between iPSCs derived from two types of commonly used somatic precursor cells. We show that the cell type of origin only minimally affects gene expression levels and DNA methylation in iPSCs. Instead, genetic variation is the main driver of regulatory differences between iPSCs of different donors. Research on human subjects is limited by the availability of samples. Practical and ethical considerations dictate that functional molecular studies in humans can generally only make use of frozen post mortem tissues, a small collection of available cell lines, or easily accessible primary cell types (such as blood or skin cells). The discovery that human somatic cells can be reprogrammed into a pluripotent state 6,7 and can then be differentiated 8 into multiple somatic lineages, has the potential to profoundly change human research by providing us access to a wide range of cell types from practically any donor individual. Though much progress has been made since the initial development of iPSC reprogramming technology, and human iPSCs have been used in a wide range of studies, the usefulness of iPSCs as a model system for the study of human phenotypes is still extensively debated