hTERT GFP for stem cell detection
Kyoto, Japan –
The concept of each tissue containing resident stem cells is not new. For example, it is known that in the liver, hepatic epithelial cells expressing common markers for hepatic and stem cells such as CD90, CD44 and CD29 act as precursors, capable of generating new hepatic tissue following injury (Khuu et al. Epithelial cells with hepatobiliary phenotype: is it another stem cell candidate for healthy adult human liver? World J Gastroenterol. 2007 Mar 14;13(10):1554-60). Additionally, hepatic stellate cells expressing CD133 have been identified has liver progenitor cells (Kordes et al. CD133+ hepatic stellate cells are progenitor cells. Biochem Biophys Res Commun. 2007 Jan 12;352(2):410-7), as well as hepatic oval cells. In the central nervous system, neuronal stem cells in the dendate gyrus are capable of proliferating following injury (Takagi et al. Proliferation of neuronal precursor cells in the dentate gyrus is accelerated after transient forebrain ischemia in mice. Brain Res. 1999 Jun 12;831(1-2):283-7).
The interesting thing about tissue specific stem cells is that they seem to all express various common properties, for example the ability to efflux nuclear-staining dyes (endowing side population properties), as well as expressing markers such as c-kit and CD133.
In a recent paper, (Tateishi et al. Clonally amplified cardiac stem cells are regulated by Sca-1 signaling for efficient cardiovascular regeneration. J Cell Sci. 2007 May 15;120(Pt 10):1791-800.) endogenous cardiac stem cells were examined in the myocardium. The investigators developed a single-cell analysis technique which allowed for determination of cardiac stem cells as possessing the marker Sca-1, and having telomerase activity.
Taking these characteristics into consideration, the investigators developed a transgenic mouse in which GFP expression is driven by the TERT promoter. This was used to demonstrate that endogenous cardiac stem cells are capable of inducing repair in animals exposed to ischemia, and that this was associated with Akt activity.
The TERT-promoter driven GFP transgenic mouse appears to be a very promising tool for investigating properties of not only cardiac stem cells but all types of tissue specific stem cells. Additionally, this model can be used for screening drugs that have “de-differentiating” activity.
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Christine Ball said...
To my knowledge they express both CD133 and Sca-1. Should email the authors to find out directly. But crap they didnt put the email on the abstract and I cant get the full text.
Its a good question, maybe a reader can do this and tell us what the response is.
Laurent said...
When you said they express CD133 and Sca-1, do you know whether the location of CD133 is changing on these stem cells? Which kind of stem cells express CD133 and Sca-1 proteins in the same time? Could you suggest me a good positive control to appreciate this co-expression?
Christine Ball said...
Well if you can abort babies it looks like neurospheres have co-expression...actually they used mice so its ok...
Stem Cells Dev. 2004 Dec;13(6):685-93. Links
Lysophosphatidic acid induces clonal generation of mouse neurospheres via proliferation of Sca-1- and AC133-positive neural progenitors.Svetlov SI, Ignatova TN, Wang KK, Hayes RL, English D, Kukekov VG.
Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA. svetlov@mbi.ufl.edu
Neural stem/progenitor cells are clonogenic in vitro and produce neurospheres in serum-free medium containing epidermal growth factor (EGF) and fibroblast growth factor (FGF2). Here, we demonstrate that lysophosphatidic acid (LPA) instigated the clonal generation of neurospheres from dissociated mouse postnatal forebrain in the absence of EGF and FGF2. LPA induced proliferation of cells which co-expressed Sca-1 antigen and AC133, markers of primitive hematopoietic and neural stem/progenitor cells. Clonal expansion of these cells induced by LPA was inhibited by diacylglycerol- pyrophosphate (DGPP), an antagonist of the LPA receptor subtypes LPA1 and LPA3. Moreover, Sca-1- and AC133-positive cells of these neurospheres expressed LPA1, LPA2, and LPA3, suggesting important roles for these LPA receptors in proliferation of neural progenitors. LPA induced neurospheres to differentiate on an adherent laminin/poly-L-ornithine matrix. In differentiating neurospheres, LPA receptors co-localized with betaIII-tubulin, nestin, and CNPase, but not with glial fibrillary acidic protein (GFAP), a marker of astrocyte lineage. Our results demonstrate for the first time that lysophosphatidic acid induces clonal neurosphere development via proliferation of AC133/Sca-1-positive stem cells by a receptor-dependent mechanism. This differentiation was characterized by the initial co-localization of neural specific antigens at sites of LPA receptor expression upon their interaction with the inducing agonist.
Laurent said...
During the differentiation of progenitor cells into differentiated cells, Sca-1 is down-regulated? what about CD133? is there a link between the both proteins?...
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Laurent said...
good morning,
I'm wondering if you know or if you have already checked whether stem cells express at the same time CD133 and Sca-1?
Regards,
Laurent