Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10721 (c-kit)
 6,575 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Scatchard binding analysis has been employed to characterize expression of low-affinity receptors for tumour necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) and granulocyte-macrophage colony-stimulating factor (GM-CSF) by isolated human placental syncytiotrophoblast microvillous plasma membrane (StMPM) vesicles. Trophoblastic receptors for the c-kit ligand (stem cell factor) could not be identified using the same methods. No high-affinity receptors could be detected for GM-CSF or IFN-gamma, but a minority of high-affinity TNF-alpha receptors were identified. Cross-inhibition studies indicated the low-affinity receptors to be specific for each cytokine rather than to be non-specific cytokine-binding factors. Only relatively high-affinity receptors for TNF-alpha and IFN-gamma could be detected on the BeWo human choriocarcinoma cytotrophoblast cell line, whereas receptor affinity for GM-CSF was similar to that on syncytiotrophoblast. Immunohistochemical staining has confirmed expression of IFN-gamma receptor by syncytiotrophoblast: in contrast, staining for the established TNF-R1 and TNF-R2 receptors was associated mainly with placental vascular endothelium. These low-affinity cytokine receptors could reflect unique biological responses of foetal syncytiotrophoblast in the presence of local concentrations of maternal cytokine.
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PMID:Low-affinity receptors for tumour necrosis factor-alpha, interferon-gamma and granulocyte-macrophage colony-stimulating factor are expressed on human placental syncytiotrophoblast. 840 76

Totipotent murine ES cells have an enormous potential for the study of cell specification. Here we demonstrate that ES cells can differentiate to hemopoietic cells through the proximal lateral mesoderm, merely upon culturing in type IV collagen-coated dishes. Separation of the Flk1+ mesoderm from other cell lineages was critical for hemopoietic cell differentiation, whereas formation of the embryoid body was not. Since the two-dimensionally spreading cells can be monitored easily in real time, this culture system will greatly facilitate the study of the mechanisms involved in the cell specification to mesoderm, endothelial, and hemopoietic cells. In the culture of ES cells, however, lineages and stages of differentiating cells can only be defined by their own characteristics. We showed that a combination of monoclonal antibodies against E-cadherin, Flk1/KDR, PDGF receptor(alpha), VE-cadherin, CD45 and Ter119 was sufficient to define most intermediate stages during differentiation of ES cells to blood cells. Using this culture system and surface markers, we determined the following order for blood cell differentiation: ES cell (E-cadherin+Flk1-PDGFRalpha-), proximal lateral mesoderm (E-cadherin-Flk1+VE-cadherin-), progenitor with hemoangiogenic potential (Flk1+VE-cadherin+CD45-), hemopoietic progenitor (CD45+c-Kit+) and mature blood cells (c-Kit-CD45+ or Ter119+), though direct differentiation of blood cells from the Flk1+VE-cadherin- stage cannot be ruled out. Not only the VE-cadherin+CD45- population generated from ES cells but also those directly sorted from the yolk sac of 9.5 dpc embryos have a potential to give rise to hemopoietic cells. Progenitors with hemoangiogenic potential were identified in both the Flk1+VE-cadherin- and Flk1+VE-cadherin+ populations by the single cell deposition experiment. This line of evidence implicates Flk1+VE-cadherin+ cells as a diverging point of hemopoietic and endothelial cell lineages.
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PMID:Progressive lineage analysis by cell sorting and culture identifies FLK1+VE-cadherin+ cells at a diverging point of endothelial and hemopoietic lineages. 952 12

Vascular endothelial growth factor (VEGF) and placental derived growth factor (PlGF) stimulate cell proliferation and differentiation by binding to their specific receptors, Flk-1/KDR and Flt-1 respectively. Flk-1/KDR-deficient murine embryos manifest failure of blood-island formation and vasculogenesis. The aim of this study was to directly evaluate the importance of VEGF, PlGF/Flt-1 and Flk-1/KDR receptor ligand interactions in regulating normal and malignant human haemopoiesis. Addition of VEGF and PlGF failed to enhance survival or cloning efficiency of human haemopoietic progenitors isolated from adult bone marrows, fetal livers or cord blood samples. This finding may be explained by the apparent absence of mRNA encoding Flt-1 and Flk-1/KDR receptors on stem cell rich CD34+ c-kit-R+ Rh123(low) cells. Further studies revealed that Fit-1 R mRNA, but not Flk-1/KDR mRNA was first detectable in the more mature cells isolated from haemopoietic colonies. Accordingly, VEGF receptors are either absent, or expressed at very low level, on human haemopoietic stem/progenitor cells. Of interest, normal and malignant human haemopoietic cells appeared to secrete VEGF protein. However, in contrast to normal haemopoietic progenitors, VEGF co-stimulated HEL cell proliferation as well as CFU-GM colony formation from approximately 15% of the chronic myeloid leukaemia (CML) and acute myeloid leukaemia (AML) patients studied. Therefore, although VEGF appeared to have minimal effects on normal haemopoietic cell growth it would appear to drive malignant haemopoietic cell proliferation to some degree. Of more importance, however, we speculate that VEGF may play an very important role in leukaemogenesis by stimulating growth of vascular endothelium, thereby providing a sufficient blood supply to feed the growing haematological tumour.
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PMID:Role of vascular endothelial growth factor (VEGF) and placenta-derived growth factor (PlGF) in regulating human haemopoietic cell growth. 988 8

The immunohistochemical profile of cardiac myxoma has been debated. The tumor is thought to be derived from multipotential undifferentiated mesenchymal cells. A consistent marker for this tumor has not been found. In this article an immunohistochemical study of 23 cardiac myxomas was accomplished. This study comprised the immunoreactivity of the tumors for thrombomodulin, calretinin and and c-kit (CD117). To the best of our knowledge, thrombomodulin and c-kit have not been tested in cardiac myxoma. Calretinin expression has been recently demonstrated in cardiac myxoma, although this finding has not been yet validated. Surface lining cells, tumor vascular endothelium, cells around the vascular slits and stromal cells embedded in the myxoid matrix were assessed independently. All tumors showed reactivity for thrombomodulin in the surface cells and in the endothelium of neoplastic vessels. 82.6% of cardiac myxomas expressed thrombomodulin in the stromal cells and 69.6% of the tumors were reactive in the perivascular cells. 73.9% of cardiac myxomas expressed calretinin in the stromal cells and in the perivascular cells. All myxomas were negative for c-kit. Thrombomodulin and calretinin may be important diagnostic aids for cardiac myxoma. Cardiac myxoma cells do not express embryonic/fetal endothelial antigens.
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PMID:Thrombomodulin, calretinin and c-kit (CD117) expression in cardiac myxoma. 1164 22

The identification of adult-derived stem cells which maintain plasticity throughout the course of a lifetime, has transformed the field of stem cell biology. Bone marrow derived hematopoietic stem cells (HSC) are the most well-characterized population of these multipotential cells. First identified for their ability to reconstitute blood lineages and rescue lethally irradiated hosts, these cells have also been shown to differentiate and integrate into skeletal muscle, cardiac myocytes, vascular endothelium, liver, and brain tissue. Various populations of HSC are being studied, exploiting cell surface marker expression, such as Sca-1, c-kit, CD34, and lin; as well as the abilityto efflux the vital dye Hoecsht 33342. Detection of engrafted donor derived cells into various tissue types in vivo is a laborious process and may involve detection of beta-galactosidase via colorimetric reaction or antibody labeling or green fluorescent protein (GFP) via fluorescence microscopy, as well as in situ hybridization to detect the Y-chromosome. Using these techniques, the search has begun for tissue specific stem cells capable of host tissue regeneration, self renewal, and transdifferentiation. Caution is urged when interpreting these types of experiments because although they are stimulating, limitations of the technologies may provide misleading results.
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PMID:Stem cells: a minireview. 1204 43

The purpose of this study was to characterize the pattern of cytokine gene expression by human corneal epithelial cells (HCEC) in response to interleukin-1 (IL-1). Primary cultured HCEC (P-HCEC) or SV40 transformed HCEC (SV40-HCEC) were treated for 6 hr with serum-free growth-media alone or with recombinant human IL-1beta or IL-1alpha (10 ng ml(-1)). 33P labeled cDNA was generated from total RNA, then hybridized to a human cytokine expression array. An autoradiograph was generated for each experimental condition and results analysed semi-quantitatively. Reverse transcription polymerase chain reaction (RT-PCR) was performed to detect mRNA for IL-8, growth related oncogene-beta (GRO-beta), intercellular adhesion molecule (ICAM)-1 and Ephrin A5. P-HCEC and SV40-HCEC demonstrated comparable cytokine profiles. For P-HCEC (n=2) the expression of 35 genes was upregulated or only detectable following IL-1beta treatment whereas the expression of nine genes was downregulated or undetectable after IL-1beta treatment. In SV40-HCEC (n=3), the expression of 48 genes was upregulated or only detectable following IL-1beta treatment and the expression of 10 genes was downregulated or undetectable after IL-1beta treatment. Some genes that demonstrated increased expression included cadherin-5, ICAM-1, GRO-alpha, GRO-beta, GRO-gamma, Activin A (bA subunit), tumor necrosis factor-alpha, IL-6, and IL-8. Genes that showed decreased expression included the chemokine receptor-CXCR-4, ciliary neurotrophic factor (CNTF), c-kit ligand, Ephrin A5, G-protein coupled receptor RDC-1 and FGF family FGFR2. Bayesian analysis of the SV40-HCEC data (n=3) revealed the expression of 15 genes that were significantly (p<0.05) differentially regulated. Within these 15 genes, the expression of chemokines (GRO-alpha, GRO-beta, IL-8), fibroblast growth factor 13 and the cytokine IL-6 were the most upregulated, while ephrin A5 and chemokine receptor-4 were the most downregulated. IL-1alpha treatment (n=1 P-HCEC; n=1 SV40-HCEC) produced results very similar to IL-1beta treatment. RT-PCR revealed differential regulation of IL-8, GRO-beta, ICAM-1 and ephrin A5 in accordance with gene array data. In conclusion, the data demonstrate that IL-1 treatment of HCEC differentially regulates the expression of other cytokine and related genes, thus adding to the body of evidence that IL-1 is a major mediator of ocular surface inflammatory reactions. Since the expression of a large number of genes can be studied simultaneously, gene array studies such as these offers the advantage of understanding global changes in response to a specific stimulus. Thus our study provides insight in to the ocular surface response in conditions of inflammation and corneal wound healing where the levels of IL-1 are known to be increased.
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PMID:The effect of interleukin-1 on cytokine gene expression by human corneal epithelial cells. 1567 Jul 96

Pterygium is a proliferative disease. Recent research has reported that stem cells are involved in the pathogenesis of various proliferative diseases, including solid tumors and diabetic proliferate vitreoretinopathy. In previous literature, we hypothesized that adult stem cells originated from bone marrow were involved in the pathogenesis of pterygium. We proved this by immunohistochemical staining with various stem cell markers. The staining showed adult stem cells in the pterygium. c-kit positive cells were observed primarily in the stroma, and some cells were also found in the basal epithelium. AC133 and CD34 positive cells were primarily found in the basal epithelium and were ovoid shaped, similar to the c-kit cells. However, some cells were found in vascular endothelium. STRO-1 positive cells were found mainly in the stroma and were spindle shaped. In recurrent pterygium, cells were more scattered and the expression pattern was denser. Therefore, we suggest a new theory of pterygium pathogenesis. Inflammation caused by environmental factors triggers the abnormal production of some growth factors and cytokines in order to recover from cellular damage. If these healing signals are excessive, limbal basal cells will be changed to abnormally-altered pterygial cells. The excessive wound healing process and remnant altered cells result in recurrence using the same mechanism.
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PMID:The involvement of adult stem cells originated from bone marrow in the pathogenesis of pterygia. 1625 68

Endometrium is a highly regenerative adult tissue that undergoes repeated degeneration and regeneration following menarche. Therefore, it is believed that endometrium contains stem and/or progenitor cells in order to compensate for the regeneration of tissue components. We report here that stem-like cells having vasculogenic potential are present in the uterus. Enzymatically extracted cells from murine uteri were characterized and fractionated into four subpopulations by flowcytometry; CD34(+)/45(-) (Ut-34), CD34(-)/45(-) (Ut-DN) and the remaining CD45(+) cell fractions (CD34(+)/45(+) and CD34(-)/45(+) cells). The Ut-34 and Ut-DN fractions were mostly negative for putative endothelial cell (EC) markers, such as CD31, Flk-1, c-kit and VE-cadherin, although the Ut-DN fraction contained 2.8% CD31(+) cells. Ut-DN cells were further divided into CD31(+) and CD31(-) fractions. Three cell populations were obtained from green fluorescence protein (GFP) transgenic mice and were transplanted into injured wild-type mouse skeletal muscle. At 4 weeks after cell transplantation, donor-derived vascular smooth muscle and ECs were observed in the injured recipient muscle. A similar trend was observed in the Ut-34 group, but differentiation into vascular smooth muscle was predominant. In contrast, the Ut-DN/31(+) cell-transplanted group showed preferential differentiation into vascular ECs, thus suggesting that they were relatively committed preexisting ECs. These characteristics were also seen in vitro, in clonal cell cultures. Interestingly, donor derived Ut-DN/31(+), Ut-DN/31(-) and Ut-34 cells could not be identified after bone marrow (BM) transplantation, thus confirming that they are not derived from BM. It therefore appeared that tissue-specific vasculogenic cells are present in the murine uterus and that they exhibit vascular formation, even in different tissue microenvironments.
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PMID:Identification of tissue-specific vasculogenic cells originating from murine uterus. 1631 38

While interstitial cells of Cajal (ICC) in the urethra respond to nitric oxide (NO) donors by increasing cGMP, it remains unclear whether urethral ICC are functionally innervated by nitrergic nerves. We have addressed this issue in the rat and sheep urethra, where cGMP production and relaxation were compared in preparations subjected to electrical field stimulation (EFS; 2 Hz, 4 min) of nitrergic nerves or to exogenous S-nitroso-L-cysteine (SNC; 0.1 mM, 4 min). Upon EFS, cGMP immunoreactivity (cGMP-ir) was observed in both smooth muscle cells (SMC) and in spindle-shaped cells that contained c-kit and vimentin, features of ICC. Similarly, cGMP-ir was preferentially, but inconsistently, found in ICC of the outer muscle layer on exposure to SNC. We found separate functional groups of ICC within the urethra. Thus only ICC present in the muscle layers (ICC-M) but not those in the serosa (ICC-SR) and lamina propia (ICC-LP) seem to be specifically influenced by activation of neuronal NO synthase (nNOS). Thus the increase in cGMP-ir in the ICC-M induced by EFS was prevented by Nomega-nitro-L-arginine and ODQ. Urethral ICC did not express nNOS, although they were closely associated with nitrergic nerves. cGMP-ir was also present in the urothelium (in the rat but not in the sheep) and the vascular endothelium but not in neural structures, such as the nerve trunks and nerve terminals. Together, these results suggest a model of parallel innervation in which both SMC and ICC-M are effectors of nerve-released NO in the urethra.
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PMID:Interstitial cells of Cajal in the urethra are cGMP-mediated targets of nitrergic neurotransmission. 1863 93

Lnk is an intracellular adaptor protein reported as a negative regulator of proliferation in c-Kit positive, Sca-1 positive, lineage marker-negative (KSL) bone marrow cells. The KSL fraction in mouse bone marrow is believed to represent a population of hematopoietic and endothelial progenitor cells (EPCs). We report here that, in vitro, Lnk(-/-) KSL cells form more EPC colonies than Lnk(+/+) KSL cells and show higher expression levels of endothelial marker genes, including CD105, CD144, Tie-1, and Tie2, than their wild-type counterparts. In vivo, the administration of Lnk(+/+) KSL cells to a mouse spinal cord injury model promoted angiogenesis, astrogliosis, axon growth, and functional recovery following injury, with Lnk(-/-) KSL being significantly more effective in inducing and promoting these regenerative events. At day 3 following injury, large vessels could be observed in spinal cords treated with KSL cells, and reactive astrocytes were found to have migrated along these large vessels. We could further show that the enhancement of astrogliosis appears to be caused in conjunction with the acceleration of angiogenesis. These findings suggest that Lnk deletion reinforces the commitment of KSL cells to EPCs, promoting subsequent repair of injured spinal cord through the acceleration of angiogenesis and astrogliosis.
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PMID:Lnk deletion reinforces the function of bone marrow progenitors in promoting neovascularization and astrogliosis following spinal cord injury. 1985 84


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