Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
999
result(s) for
"Robbins, Robert"
Sort by:
Feeder-free derivation of induced pluripotent stem cells from adult human adipose stem cells
Ectopic expression of transcription factors can reprogram somatic cells to a pluripotent state. However, most of the studies used skin fibroblasts as the starting population for reprogramming, which usually take weeks for expansion from a single biopsy. We show here that induced pluripotent stem (iPS) cells can be generated from adult human adipose stem cells (hASCs) freshly isolated from patients. Furthermore, iPS cells can be readily derived from adult hASCs in a feeder-free condition, thereby eliminating potential variability caused by using feeder cells. hASCs can be safely and readily isolated from adult humans in large quantities without extended time for expansion, are easy to maintain in culture, and therefore represent an ideal autologous source of cells for generating individual-specific iPS cells.
Journal Article
Single cell transcriptional profiling reveals heterogeneity of human induced pluripotent stem cells
Human induced pluripotent stem cells (hiPSCs) and human embryonic stem cells (hESCs) are promising candidate cell sources for regenerative medicine. However, despite the common ability of hiPSCs and hESCs to differentiate into all 3 germ layers, their functional equivalence at the single cell level remains to be demonstrated. Moreover, single cell heterogeneity amongst stem cell populations may underlie important cell fate decisions. Here, we used single cell analysis to resolve the gene expression profiles of 362 hiPSCs and hESCs for an array of 42 genes that characterize the pluripotent and differentiated states. Comparison between single hESCs and single hiPSCs revealed markedly more heterogeneity in gene expression levels in the hiPSCs, suggesting that hiPSCs occupy an alternate, less stable pluripotent state. hiPSCs also displayed slower growth kinetics and impaired directed differentiation as compared with hESCs. Our results suggest that caution should be exercised before assuming that hiPSCs occupy a pluripotent state equivalent to that of hESCs, particularly when producing differentiated cells for regenerative medicine aims.
Journal Article
Transcriptional and Functional Profiling of Human Embryonic Stem Cell-Derived Cardiomyocytes
Human embryonic stem cells (hESCs) can serve as a potentially limitless source of cells that may enable regeneration of diseased tissue and organs. Here we investigate the use of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) in promoting recovery from cardiac ischemia reperfusion injury in a mouse model. Using microarrays, we have described the hESC-CM transcriptome within the spectrum of changes that occur between undifferentiated hESCs and fetal heart cells. The hESC-CMs expressed cardiomyocyte genes at levels similar to those found in 20-week fetal heart cells, making this population a good source of potential replacement cells in vivo. Echocardiographic studies showed significant improvement in heart function by 8 weeks after transplantation. Finally, we demonstrate long-term engraftment of hESC-CMs by using molecular imaging to track cellular localization, survival, and proliferation in vivo. Taken together, global gene expression profiling of hESC differentiation enables a systems-based analysis of the biological processes, networks, and genes that drive hESC fate decisions, and studies such as this will serve as the foundation for future clinical applications of stem cell therapies.
Journal Article
Haematopoietic stem cells adopt mature haematopoietic fates in ischaemic myocardium
Under conditions of tissue injury, myocardial replication and regeneration have been reported
1
. A growing number of investigators have implicated adult bone marrow (BM) in this process, suggesting that marrow serves as a reservoir for cardiac precursor cells
2
,
3
,
4
,
5
,
6
. It remains unclear which BM cell(s) can contribute to myocardium, and whether they do so by transdifferentiation or cell fusion. Here, we studied the ability of c-kit-enriched BM cells, Lin
-
c-kit
+
BM cells and c-kit
+
Thy1.1
lo
Lin
-
Sca-1
+
long-term reconstituting haematopoietic stem cells to regenerate myocardium in an infarct model. Cells were isolated from transgenic mice expressing green fluorescent protein (GFP) and injected directly into ischaemic myocardium of wild-type mice. Abundant GFP
+
cells were detected in the myocardium after 10 days, but by 30 days, few cells were detectable. These GFP
+
cells did not express cardiac tissue-specific markers, but rather, most of them expressed the haematopoietic marker CD45 and myeloid marker Gr-1. We also studied the role of circulating cells in the repair of ischaemic myocardium using GFP
+
–GFP
-
parabiotic mice. Again, we found no evidence of myocardial regeneration from blood-borne partner-derived cells. Our data suggest that even in the microenvironment of the injured heart, c-kit-enriched BM cells, Lin
-
c-kit
+
BM cells and c-kit
+
Thy1.1
lo
Lin
-
Sca-1
+
long-term reconstituting haematopoietic stem cells adopt only traditional haematopoietic fates.
Journal Article
A nonviral minicircle vector for deriving human iPS cells
Simple minicircle vectors carrying four reprogramming factors induce pluripotency in adult human adipose stem cells and in neonatal fibroblasts without integration into the genome.
Owing to the risk of insertional mutagenesis, viral transduction has been increasingly replaced by nonviral methods to generate induced pluripotent stem cells (iPSCs). We report the use of 'minicircle' DNA, a vector type that is free of bacterial DNA and capable of high expression in cells, for this purpose. Here we use a single minicircle vector to generate transgene-free iPSCs from adult human adipose stem cells.
Journal Article
Generation of adult human induced pluripotent stem cells using nonviral minicircle DNA vectors
Human induced pluripotent stem cells (hiPSCs) derived from patient samples have tremendous potential for innovative approaches to disease pathology investigation and regenerative medicine therapies. However, most hiPSC derivation techniques use integrating viruses, which may leave residual transgene sequences as part of the host genome, thereby unpredictably altering cell phenotype in downstream applications. In this study, we describe a protocol for hiPSC derivation by transfection of a simple, nonviral minicircle DNA construct into human adipose stromal cells (hASCs). Minicircle DNA vectors are free of bacterial DNA and thus capable of high expression in mammalian cells. Their repeated transfection into hASCs, abundant somatic cell sources that are amenable to efficient reprogramming, results in transgene-free hiPSCs. This protocol requires only readily available molecular biology reagents and expertise, and produces hiPSC colonies from an adipose tissue sample in ∼4 weeks.
Journal Article
What Can Eye Movements Tell Us about Reading in a Second Language: A Scoping Review of the Literature
There is a growing interest in the similarities and differences in reading processes in L1 and L2. Some researchers propose that reading shares commonalities across languages, while others state that each language has particularities that would affect reading processes. One way to better understand the reading processes is by using eye-tracking methodologies to explore reading processes online. This review focuses on the research done about reading processes in bilinguals to understand the effect of L1 in L2 processing. We found that most of the studies followed two methods of comparison: Bilinguals vs. monolinguals and L1 vs. L2. In general, bilinguals presented longer times in all reading measures; however, the results are discussed based on different characteristics of the studies and the type of comparison.
Journal Article
Immunosuppressive Therapy Mitigates Immunological Rejection of Human Embryonic Stem Cell Xenografts
Given their self-renewing and pluripotent capabilities, human embryonic stem cells (hESCs) are well poised as a cellular source for tissue regeneration therapy. However, the host immune response against transplanted hESCs is not well characterized. In fact, controversy remains as to whether hESCs have immune-privileged properties. To address this issue, we used in vivo bioluminescent imaging to track the fate of transplanted hESCs stably transduced with a double-fusion reporter gene consisting of firefly luciferase and enhanced GFP. We show that survival after transplant is significantly limited in immunocompetent as opposed to immunodeficient mice. Repeated transplantation of hESCs into immunocompetent hosts results in accelerated hESC death, suggesting an adaptive donor-specific immune response. Our data demonstrate that transplanted hESCs trigger robust cellular and humoral immune responses, resulting in intragraft infiltration of inflammatory cells and subsequent hESC rejection. Moreover, we have found CD4⁺ T cells to be an important modulator of hESC immune-mediated rejection. Finally, we show that immunosuppressive drug regimens can mitigate the anti-hESC immune response and that a regimen of combined tacrolimus and sirolimus therapies significantly prolongs survival of hESCs for up to 28 days. Taken together, these data suggest that hESCs are immunogenic, trigger both cellular and humoral-mediated pathways, and, as a result, are rapidly rejected in xenogeneic hosts. This process can be mitigated by a combined immunosuppressive regimen as assessed by molecular imaging approaches.
Journal Article
Functional and Transcriptional Characterization of Human Embryonic Stem Cell-Derived Endothelial Cells for Treatment of Myocardial Infarction
Differentiation of human embryonic stem cells into endothelial cells (hESC-ECs) has the potential to provide an unlimited source of cells for novel transplantation therapies of ischemic diseases by supporting angiogenesis and vasculogenesis. However, the endothelial differentiation efficiency of the conventional embryoid body (EB) method is low while the 2-dimensional method of co-culturing with mouse embryonic fibroblasts (MEFs) require animal product, both of which can limit the future clinical application of hESC-ECs. Moreover, to fully understand the beneficial effects of stem cell therapy, investigators must be able to track the functional biology and physiology of transplanted cells in living subjects over time.
In this study, we developed an extracellular matrix (ECM) culture system for increasing endothelial differentiation and free from contaminating animal cells. We investigated the transcriptional changes that occur during endothelial differentiation of hESCs using whole genome microarray, and compared to human umbilical vein endothelial cells (HUVECs). We also showed functional vascular formation by hESC-ECs in a mouse dorsal window model. Moreover, our study is the first so far to transplant hESC-ECs in a myocardial infarction model and monitor cell fate using molecular imaging methods.
Taken together, we report a more efficient method for derivation of hESC-ECs that express appropriate patterns of endothelial genes, form functional vessels in vivo, and improve cardiac function. These studies suggest that hESC-ECs may provide a novel therapy for ischemic heart disease in the future.
Journal Article