Search results for " STEM"
showing 10 items of 2170 documents
Occurrence and regional distribution of striated muscle fibers in the rat pineal gland
1978
In a total of 96 rat pineals studied 31 were found to contain striated muscle fibers or their precursors. The muscle fibers were most frequently present in the stalk region and more frequently found in the left than in the right hemisphere. Size measurements revealed that the lengths of pineal muscle cell nuclei differ only slightly from those of the sphincter muscle of the iris. However, the yellowish appearance of pineal muscle cell nuclei under darkfield investigation, a phenomenon observed in all muscular tissues of mesenchymal origin and connective tissue cells, may support the hypothesis that pineal musculature is of mesenchymal rather than ectodermal origin.
Chromogranin A in the Mammalian Merkel Cell: Cellular and Subcellular Distribution
1989
Chromogranin-A (CGA), which accounts for more than half the soluble matrix protein in secretory granules of various neuroendocrine cells, has a wide spectrum of potential biological roles and is considered an important marker of the diffuse neuroendocrine system (DNES). Light and electron microscopic immunohistochemistry of mammalian skin revealed that Merkel cells are exclusively CGA-immunoreactive (ir) and that the immunoreaction is localized in the secretory granules. This finding supports the classification of the Merkel cell as a member of the DNES. The CGA immunoreactivity was restricted to Merkel cells of pigs and humans. In human embryonic skin, CGA was expressed in Merkel cells as …
Tenascin gene expression in rat liver and in rat liver cells. In vivo and in vitro studies.
1991
Tenascin is a major glycoprotein constituent of the extracellular matrix with a strong affinity to fibronectin; its distribution is believed to be temporarily and spatially limited. Tenascin gene expression is increased during wound healing processes. As repair mechanisms in chronic liver diseases resemble wound healing we studied tenascin gene expression in rat liver and in isolated rat liver cells. In normal rat liver a tenascin specific antiserum stains sinusoidal cells with fiber-like prolongations, which at the same time are desmin-positive (ITO-cells). In the CCl4-acutely-damaged liver a strong tenascin staining is detected in cells located among the mononuclear cells of the inflammat…
Cilium induction triggers differentiation of glioma stem cells.
2020
Glioblastoma multiforme (GBM) possesses glioma stem cells (GSCs) that promote self-renewal, tumor propagation, and relapse. Understanding the mechanisms of GSCs self-renewal can offer targeted therapeutic interventions. However, insufficient knowledge of GSCs' fundamental biology is a significant bottleneck hindering these efforts. Here, we show that patient-derived GSCs recruit elevated levels of proteins that ensure the temporal cilium disassembly, leading to suppressed ciliogenesis. Depleting the cilia disassembly complex components is sufficient to induce ciliogenesis in a subset of GSCs via relocating platelet-derived growth factor receptor-alpha (PDGFR-α) to a newly induced cilium. Im…
MiR-33a Controls hMSCS Osteoblast Commitment Modulating the Yap/Taz Expression Through EGFR Signaling Regulation
2019
Mesenchymal stromal cells (hMSCs) display a pleiotropic function in bone regeneration. The signaling involved in osteoblast commitment is still not completely understood, and that determines the failure of current therapies being used. In our recent studies, we identified two miRNAs as regulators of hMSCs osteoblast differentiation driving hypoxia signaling and cytoskeletal reorganization. Other signalings involved in this process are epithelial to mesenchymal transition (EMT) and epidermal growth factor receptor (EGFR) signalings through the regulation of Yes-associated protein (YAP)/PDZ-binding motif (TAZ) expression. In the current study, we investigated the role of miR-33a family as a (…
Aislamiento, cultivo, caracterización y maduración de células indiferenciadas desde biopsias testiculares humanas
2013
En el testículo existe una población de células pluripotentes, las Espermatogonias Stem Cells (SSC), responsables de la autorrenovación y la diferenciación, manteniendo así la espermatogénesis. La espermatogénesis es el proceso en el cual la espermatogonia sufre una serie de divisiones hasta originar el espermatozoide, que son las células fundamentales para transmitir la información genética a las generaciones futuras. Recientemente, han sido publicados una serie de estudios mostrando la posibilidad de generar células pluripotentes a partir de biopsias testiculares humanas de individuos adultos (Conrad et al., 2008; Kossack et al. ,2008). Los resultados obtenidos en éstos trabajos en humano…
Synthesis and Antiproliferative Activity of 2,5-bis(3′-Indolyl)pyrroles, Analogues of the Marine Alkaloid Nortopsentin
2013
2,5-bis(3′-Indolyl)pyrroles, analogues of the marine alkaloid nortopsentin, were conveniently prepared through a three step procedure in good overall yields. Derivatives 1a and 1b exhibited concentration-dependent antitumor activity towards a panel of 42 human tumor cell lines with mean IC50 values of 1.54 μM and 0.67 μM, respectively. Investigating human tumor xenografts in an ex-vivo clonogenic assay revealed selective antitumor activity, whereas sensitive tumor models were scattered among various tumor histotypes.
Unveiling neural stem cell quiescence: a crosstalk with the extracellular matrix niche
2023
Neural stem cells (NSCs) in the subependymal zone (SEZ) reside in a very specialized microenvironment that tightly regulates their activation state. Three NSC populations coexist in the niche, quiescent (qNSCs), primed and activated (aNSCs), which display unique, actively modulated, molecular identities. One of the specialized extrinsic properties that affect NSC quiescence-to-activation transitions is the extracellular matrix (ECM). The SEZ is the only region in the whole mouse brain that has two basement membrane (BM) structures: vascular and speckled BMs. Further, it displays higher stiffness compared to non-neurogenic areas, suggesting that both composition and ECM properties could part…
Paracrine roles of extracellular vesicles released by mouse mesoangioblasts
2017
Extracellular vesicles (EV) represent an important mediator of cell-to-cell communication and are involved in both autocrine and paracrine signaling, with a critical role in a number of physiological and pathological conditions.1 The bioactive molecules contained within EV simultaneously activate several different pathways resulting in the synergistic stimulation of target cells. The discovery and characterization of EV have added a novel understanding to regenerative medicine, namely the finding that stem cells are an abundant source of EV.1-2 A6 mouse mesoangioblasts, vessel-associated multipotent progenitor stem cells that are capable of differentiating into different mesodermal cell typ…
Systems level approach reveals the correlation of endoderm differentiation of mouse embryonic stem cells with specific microstructural cues of fibrin…
2014
Stem cells receive numerous cues from their associated substrate that help to govern their behaviour. However, identification of influential substrate characteristics poses difficulties because of their complex nature. In this study, we developed an integrated experimental and systems level modelling approach to investigate and identify specific substrate features influencing differentiation of mouse embryonic stem cells (mESCs) on a model fibrous substrate, fibrin. We synthesized a range of fibrin gels by varying fibrinogen and thrombin concentrations, which led to a range of substrate stiffness and microstructure. mESCs were cultured on each of these gels, and characterization of the diff…