A Low-Molecular-Weight Factor Extracted from Human Placenta Inhibits the Entry into Cell Cycle of Murine Pluripotent Stem Cells

Transplantation of cardiomyocytes derived from induced pluripotent stem cells (iPSCs) improves cardiac function in animal models with myocardial infarction. However, the poor number of survived cells and the low proliferation capability of cardiomyocyte derived from iPSCs are bottlenecks in myocardial repair with cell therapy. We hypothesize that increasing the number of surviving iPSC-CMs in the engraftment via cell cycle induction may lead to a transmural replacement of scar tissue and a lasting restoration of cardiac function. Cyclin D2 is a protein that regulates cell cycle transition from G1 to S phase. We transfected MHC-cyclin D2 (designated as MHC-cycD2) cDNA into the iPSCs, and differentiated the iPSCs into cardiomyocytes. Comparing to non-expressing cells, MHC-cycD2-expressing cardiomyocytes displayed increased Brdu incorporation activity, suggesting the enhanced cell cycle in MHC-cycD2-expressing cardiomyocytes. Cell cycle activity was confirmed by increased number of Ki-67 and PCNA positive immunostaining cardiomyocytes and more contractile embryonic body cell mass in MHC-cycD2-expressing culture compared to non-expressing culture. Data from Q-PCR and histology suggested that expression of MHC-cycD2 didn’t alter the pluripotency or cardiomyogenic potential of iPSCs. Thus, we have successfully induced cell cycle in iPSC-derived cardiomyocytes via expression of cyclin D2. We are currently studying if MHC-cycD2-expressing iPSC-cardiomyocytes exhibit superior regenerative potential compared to their non-expressing counterparts following transplantation into chronically infarcted hearts.

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Low Molecular Weight Fraction of Commercial Human Serum Albumin Induces Morphologic and Transcriptional Changes of Bone Marrow-Derived Mesenchymal Stem Cells

Stem Cells Translational Medicine ◽

10.5966/sctm.2014-0293 ◽

2015 ◽

Vol 4 (8) ◽

pp. 945-955 ◽

Cited By ~ 16

Author(s):

David Bar-Or ◽

Gregory W. Thomas ◽

Leonard T. Rael ◽

Elizabeth D. Gersch ◽

Pablo Rubinstein ◽

...

Keyword(s):

Stem Cells ◽

Molecular Weight ◽

Bone Marrow ◽

Mesenchymal Stem Cells ◽

Human Serum Albumin ◽

Serum Albumin ◽

Human Serum ◽

Weight Fraction ◽

Low Molecular Weight ◽

Transcriptional Changes

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A Src inhibitor regulates the cell cycle of human pluripotent stem cells and improves directed differentiation

The Journal of Cell Biology ◽

10.1083/jcb.201502035 ◽

2015 ◽

Vol 210 (7) ◽

pp. 1257-1268 ◽

Cited By ~ 20

Author(s):

Sundari Chetty ◽

Elise N. Engquist ◽

Elie Mehanna ◽

Kathy O. Lui ◽

Alexander M. Tsankov ◽

...

Keyword(s):

Cell Cycle ◽

Stem Cells ◽

Pluripotent Stem Cells ◽

Human Pluripotent Stem Cells ◽

Directed Differentiation ◽

Differentiation Potential ◽

Germ Layers ◽

Positive Effects ◽

Src Inhibitor ◽

Expression Of Genes

Driving human pluripotent stem cells (hPSCs) into specific lineages is an inefficient and challenging process. We show that a potent Src inhibitor, PP1, regulates expression of genes involved in the G1 to S phase transition of the cell cycle, activates proteins in the retinoblastoma family, and subsequently increases the differentiation propensities of hPSCs into all three germ layers. We further demonstrate that genetic suppression of Src regulates the activity of the retinoblastoma protein and enhances the differentiation potential of hPSCs across all germ layers. These positive effects extend beyond the initial germ layer specification and enable efficient differentiation at subsequent stages of differentiation.

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Two Related Subpellicular Cytoskeleton-associated Proteins inTrypanosoma brucei Stabilize Microtubules

Molecular Biology of the Cell ◽

10.1091/mbc.01-06-0298 ◽

2002 ◽

Vol 13 (3) ◽

pp. 1058-1070 ◽

Cited By ~ 26

Author(s):

Cécile Vedrenne ◽

Christiane Giroud ◽

Derrick R. Robinson ◽

Sébastien Besteiro ◽

Christophe Bosc ◽

...

Keyword(s):

Cell Cycle ◽

Molecular Weight ◽

Trypanosoma Brucei ◽

Cold Resistance ◽

Chinese Hamster ◽

Low Molecular Weight ◽

Microtubule Bundle ◽

Microtubule Associated Proteins ◽

Associated Proteins ◽

Asymmetric Cytokinesis

The subpellicular microtubules of the trypanosome cytoskeleton are cross-linked to each other and the plasma membrane, creating a cage-like structure. We have isolated, from Trypanosoma brucei, two related low-molecular-weight cytoskeleton-associated proteins (15- and 17-kDa), called CAP15 and CAP17, which are differentially expressed during the life cycle. Immunolabeling shows a corset-like colocalization of both CAPs and tubulin. Western blot and electron microscope analyses show CAP15 and CAP17 labeling on detergent-extracted cytoskeletons. However, the localization of both proteins is restricted to the anterior, microtubule minus, and less dynamic half of the corset. CAP15 and CAP17 share properties of microtubule-associated proteins when expressed in heterologous cells (Chinese hamster ovary and HeLa), colocalization with their microtubules, induction of microtubule bundle formation, cold resistance, and insensitivity to nocodazole. When overexpressed inT. brucei, both CAP15 and CAP17 cover the whole subpellicular corset and induce morphological disorders, cell cycle-based abnormalities, and subsequent asymmetric cytokinesis.

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