| 1. |
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| 2. |
- Akyürek, L M, et al.
(författare)
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Tolerance induction ameliorates allograft vasculopathy in rat aortic transplants. Influence of Fas-mediated apoptosis.
- 1998
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Ingår i: The Journal of clinical investigation. - 0021-9738. ; 101:12, s. 2889-99
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Tidskriftsartikel (refereegranskat)abstract
- Based on successful induction of donor-specific unresponsiveness by alloantigenic stimulation in several animal models of acute rejection, we hypothesized that similar immune manipulations would also inhibit the evolution of chronic rejection and transplant vasculopathy. To induce immune tolerance, DA rats received a PVG heart allograft and were immunosuppressed with cyclosporine for 30 d. At day 100 the animals were challenged with a PVG aortic allograft after either 1 or 18 h of cold ischemia. 8 wk after the aortic transplantation, the grafts were investigated for morphological changes, infiltrating cells, apoptosis, and Fas-Fas ligand expression. Control allografts showed advanced transplant arteriosclerosis, whereas tolerance-induced aortic allografts displayed reduced neointimal formation, less medial atrophy, fewer apoptotic cells, and fewer Fas- and FasL-expressing cells. Prolonged ischemic storage time did not profoundly alter the morphological changes of the allografts. Fas expression was found in T cells, macrophages, vascular smooth muscle cells, and endothelial cells, whereas FasL was expressed mainly by T cells and macrophages. FasL mRNA expression was evident throughout the entire allograft wall. In conclusion, induction of allospecific tolerance can effectively prevent transplant arteriosclerosis. Cold ischemia damage does not abrogate the beneficial effect of tolerance, but creates a separate identity of mainly endothelial lesions. Furthermore, Fas-mediated apoptosis appears to be involved in the pathological lesions seen in chronic rejection.
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| 3. |
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| 4. |
- Andrae, Johanna, et al.
(författare)
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Platelet-derived growth factor-B and -C and active alpha-receptors in medulloblastoma cells.
- 2002
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Ingår i: Biochemical and biophysical research communications. - 0006-291X .- 1090-2104. ; 296:3, s. 604-11
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Tidskriftsartikel (refereegranskat)abstract
- The malignant childhood brain tumor medulloblastoma belongs to the group of primitive neuroectodermal tumours (PNETs). Medulloblastomas are thought to arise from remnants of the transient external germinal layer in the cerebellum. Proliferation, differentiation, and motility of cells in the central nervous system are regulated by growth factors, e.g., platelet-derived growth factor (PDGF). Recently, it was shown that higher level of PDGF alpha-receptor expression is characteristic of metastatic medulloblastomas. We have investigated five medulloblastoma/PNET cell lines and found that the PDGF alpha-receptor is actively signalling in most of them, an activity most likely driven by endogenously produced PDGF-C. PDGF-C is normally present in cells of the developing external germinal layer and our results are consistent with the idea that medulloblastomas are derived from such cells undergoing early neuronal differentiation. Moreover, the expression of PDGF and its receptors was associated with neuronal characteristics, but not with high levels of c-myc expression in the medullablastoma cells.
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| 5. |
- Arvidsson, Yvonne, 1960, et al.
(författare)
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ASK1 resistant neuroblastoma is deficient in activation of p38 kinase.
- 2001
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Ingår i: Cell death and differentiation. - : Springer Science and Business Media LLC. - 1350-9047 .- 1476-5403. ; 8:10, s. 1029-37
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Tidskriftsartikel (refereegranskat)abstract
- Apoptosis Signal-regulating Kinase 1 (ASK1) is known to either induce apoptosis or differentiation in various cell lines of neuronal origin. We analyzed the effect of the constitutively active mutant of ASK1 (ASK1-Delta N) in an adenoviral vector in four neuroblastoma cell lines, two murine, C1300 and NXS2, and two human, SH-SY5Y and IMR-32. Already after 24 h upon infection, C1300 and SH-SY5Y cells arrested in growth when judged by [(3)H]thymidine incorporation, and the majority of the cells demonstrated apoptotic appearance, which was confirmed by DNA-laddering in gel electrophoresis. In contrast, NXS2 and IMR-32 cell lines remained unaffected. Immunoblotting revealed strongly phosphorylated p38 MAPK accompanied by weakly phosphorylated JNK in C1300 and SH-SY5Y, whereas none of these kinases were activated by adenoviruses expressing the kinase negative ASK1 mutant or beta-galactosidase. There was no expression of phosphorylated kinases in IMR-32 cells, but NXS2 showed a faint band of phosphorylated p38 MAPK. Addition of the p38 MAPK specific inhibitor, SB203580, protected C1300 and SH-SY5Y cells from apoptosis induced by ASK1-Delta N. The anti-neoplastic agent, paclitaxel, activates ASK1 and JNK, and promotes the in vitro assembly of stable microtubules. Addition of 10 nM paclitaxel sensitised the NXS2 cell line to ASK1-induced cell death. Our results indicate that ASK1 induces apoptosis in neuroblastoma cells mainly via the p38 MAPK pathway, and resistant neuroblastoma cells can be sensitised to ASK1 by paclitaxel.
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| 6. |
- Arvidsson, Yvonne, 1960, et al.
(författare)
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Neuroblastoma-specific cytotoxicity mediated by the Mash1-promoter and E. coli purine nucleoside phosphorylase.
- 2005
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Ingår i: Pediatric blood & cancer. - : Wiley. - 1545-5009 .- 1545-5017. ; 44:1, s. 77-84
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Neuroblastoma is derived from cells of neural crest origin and often expresses the transcription factor human achaete-scute homolog 1 (HASH1). The aim of this study was to selectively kill neuroblastoma cells by expressing the suicide gene E. coli purine nucleoside phosphorylase (PNP) under the control of the Mash1 promoter, the murine homolog of HASH1. PROCEDURE: The E. coli PNP gene regulated by the Mash1 promoter was cloned into an expression vector and transfected into neuroblastoma and non-neuroblastoma cell lines. After addition of the prodrug M2-fluoroadenine 9-beta-D-arabinofuranoside (F-araA) the cell-specific toxicity was examined. To optimize the cell specific activity, different sizes of the Mash1 promoter were analyzed in neuroblastoma cell lines and compared with the activity in non-neuroblastoma cells. RESULTS: Estimated as the percentages of CMV enhancer-promoter, the activity was significantly higher in the neuroblastoma cells, ranging from 17 to 58% when the shortest and the most active promoter was measured. The non-neuroblastoma cells yielded only 1-6% of the CMV promoter activity. When the shortest Mash1 promoter was combined with the E. coli PNP gene the cytotoxicity was 65% in the neuroblastoma cells with low cell death in the non-neuroblastoma cell lines, relative to the cytotoxicity where the E.coli PNP gene was regulated by the strong but non-specific CMV enhancer-promoter. CONCLUSIONS: We show here that the Mash1 promoter regulating the PNP gene confers a cell-type selective toxicity in neuroblastoma cell lines. These results indicate the feasibility to use the Mash1 promoter for regulating E.coli PNP expression in gene-directed enzyme prodrug therapy (GDEPT) of neuroblastoma.
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| 7. |
- Ata, A K, et al.
(författare)
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Expression of various TGF-beta isoforms and type I receptor in necrotizing human brain lesions.
- 1997
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Ingår i: Acta neuropathologica. - 0001-6322. ; 93:4, s. 326-33
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Tidskriftsartikel (refereegranskat)abstract
- It is known that transforming growth factor beta (TGF-beta) is involved in the modulation of cell growth, differentiation, and repair following injury. We performed an immunohistochemical study of human brain autopsy and biopsy material for the expression of TGF-beta isoforms beta 1, beta 2 and beta 3, and TGF-beta receptor (T beta R) type I in different cells of necrotizing lesions such as infarction and abscess, and compared them with controls. Various cell types, both inside and in the proximity of lesions, showed immunoreactivity indicating the presence of all three isoforms. Significant values of immunoreaction for various TGF-beta s and T beta R-I were observed in cells such as astrocytes, macrophages, neurons, microvascular endothelial cells, and granulocytes. In the control cases, comprising biopsy material without necrotizing lesions, a prominent TGF-beta 2 immunoreactivity was observed in glial cells and neurons. TGF-beta 1 and TGF-beta 3 reactivity in controls, when compared with TGF-beta 2, was less. T beta R-I antiserum showed clear and distinct signals in the same type of cells as for TGF-beta s in the necrotizing lesions with varying values of significance. Our findings suggest that TGF-beta s and their receptor type I are involved in reactive processes around necrotizing human brain lesions like glial and macrophage responses, angiogenesis, and deposition of extracellular matrix.
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| 8. |
- Ata, K A, et al.
(författare)
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Expression of transforming growth factor-beta1, 2, 3 isoforms and type I and II receptors in acute focal cerebral ischemia: an immunohistochemical study in rat after transient and permanent occlusion of middle cerebral artery.
- 1999
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Ingår i: Acta neuropathologica. - 0001-6322. ; 97:5, s. 447-55
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Tidskriftsartikel (refereegranskat)abstract
- Transforming growth factor beta (TGF-beta) is involved in the modulation of cell growth, differentiation and repair following injury of various organs. Previous studies on human autopsy material have indicated that TGF-beta isoforms-beta1, -beta2 and -beta3, and TGF-beta receptor type I are expressed in various cells of necrotizing brain lesions like infarction and abscess. The present immunohistochemical study was designed to investigate changes that may occur with regard to TGF-beta and its receptors type I and II in a rat model of focal brain ischemia induced by transient or permanent occlusion of the middle cerebral artery. Our findings indicate that at days 1 and 3 following such transient and permanent ischemia there is an up-regulation of TGF-beta isoforms -beta1, -beta2 and -beta3, and TGF-beta receptor types I and II mainly in the perifocal neurons, reactive astroglial cells, endothelial cells and macrophages.
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| 9. |
- Botchkarev, Vladimir A, et al.
(författare)
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Modulation of BMP signaling by noggin is required for induction of the secondary (nontylotrich) hair follicles.
- 2002
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Ingår i: The Journal of investigative dermatology. - : Elsevier BV. - 0022-202X. ; 118:1, s. 3-10
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Tidskriftsartikel (refereegranskat)abstract
- Increasing evidence suggests that morphogenesis of the distinct developmental structures derived from the same organ-committed epithelium is controlled by differential mechanisms. As was recently shown in mice with mutations in the downless (dL) gene, induction of primary or tylotrich hair follicles is strikingly dependent of signaling through the Tnf receptor homologue, Edar. Here, we show that dorsal skin of murine embryos with constitutive deletion of the BMP2/4 antagonist noggin, after transplantation into SCID mice, is characterized by the lack of induction of secondary hair follicles, and by the arrest of primary hair follicle development prior to hair shaft formation. The loss of noggin activity was associated with failure to express genes that specify hair follicle cell fates in the epidermis (Lef-1, beta-catenin, Shh) and dermal papilla (p75 kDa neurotrophin receptor, alkaline phosphatase). This suggests that regulation of BMP2/4 signaling by noggin is essential for the induction of secondary hair follicles, as well as for advanced stages of development in primary hair follicles.
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| 10. |
- Botchkarev, V A, et al.
(författare)
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Noggin is required for induction of the hair follicle growth phase in postnatal skin.
- 2001
-
Ingår i: FASEB journal : official publication of the Federation of American Societies for Experimental Biology. - : Wiley. - 1530-6860. ; 15:12, s. 2205-14
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Tidskriftsartikel (refereegranskat)abstract
- During postnatal development, the hair follicle (HF) shows cyclic activity with periods of relative resting, active growth (anagen), and regression. We demonstrate that similar to the HF induction in embryonic skin, initiation of a new hair growth phase in postnatal skin requires neutralization of the inhibitory activity of bone morphogenetic protein 4 (BMP4) by the BMP antagonist noggin. In the resting HF, BMP4 mRNA predominates over noggin in the epithelium and mesenchyme, and the BMP receptor IA is prominently expressed in the follicular germ. Anagen development is accompanied by down-regulation of the BMP4 and increased noggin mRNA in the HF. Furthermore, administration of noggin protein induces new hair growth phase in postnatal telogen skin in vivo. In contrast, BMP4 induces selective arrest of anagen development in the non-tylotrich (secondary) HF. As a hair growth inducer, noggin increases Shh mRNA in the HF whereas BMP4 down-regulates Shh. This suggests that modulation of BMP4 signaling by noggin is essential for hair growth phase induction in postnatal skin and that the hair growth-inducing effect of noggin is mediated, at least in part, by Shh.
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| 11. |
- Brederlau, Anke, 1968, et al.
(författare)
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Bone morphogenetic proteins but not growth differentiation factors induce dopaminergic differentiation in mesencephalic precursors.
- 2002
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Ingår i: Molecular and cellular neurosciences. - 1044-7431. ; 21:3, s. 367-78
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Tidskriftsartikel (refereegranskat)abstract
- Bone morphogenetic proteins (BMPs) and growth differentiation factors (GDFs) are potential therapeutic molecules for the treatment of Parkinson's disease (PO). Here we compare the effects of BMP3, 5, 6, and 7 and GDF5 and 6 in a rat mesencephalic cell culture system that reflects the developmental stage of neurons around birth. High concentrations of BMP5, 6, and 7 and GDF5 and 6 induced astroglial cell fate and a depletion of oligodendrocytes. Only BMP5, 6, and 7, however, significantly increased the number of tyrosine hydroxylase (TH)-positive neurons and induced nuclear translocation of the phosphorylated BMP-restricted Smad in a substantial number of TH- and microtubule-associated protein 2(MAP2ab)-positive cells. None of the proteins protected TH-positive cells against 6-hydroxydopamine-induced oxidative stress. BMP3 was without any effect throughout the studies. We conclude that BMP5, 6, and 7 act directly and independently on precursors of the dopaminergic and astroglial lineage and induce their differentiation. In contrast, GDF5 and 6 primarily affect nonneuronal cells in mesencephalic cultures of this stage.
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| 12. |
- Brederlau, Anke, 1968, et al.
(författare)
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The bone morphogenetic protein type Ib receptor is a major mediator of glial differentiation and cell survival in adult hippocampal progenitor cell culture.
- 2004
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Ingår i: Molecular biology of the cell. - 1059-1524. ; 15:8, s. 3863-75
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Tidskriftsartikel (refereegranskat)abstract
- Bone morphogenetic proteins (BMPs) act as growth regulators and inducers of differentiation. They transduce their signal via three different type I receptors, termed activin receptor-like kinase 2 (Alk2), Alk3, or bone morphogenetic protein receptor Ia (BMPRIa) and Alk6 or BMPRIb. Little is known about functional differences between the three type I receptors. Here, we have investigated consequences of constitutively active (ca) and dominant negative (dn) type I receptor overexpression in adult-derived hippocampal progenitor cells (AHPs). The dn receptors have a nonfunctional intracellular but functional extracellular domain. They thus trap BMPs that are endogenously produced by AHPs. We found that effects obtained by overexpression of dnAlk2 and dnAlk6 were similar, suggesting similar ligand binding patterns for these receptors. Thus, cell survival was decreased, glial fibrillary acidic protein (GFAP) expression was reduced, whereas the number of oligodendrocytes increased. No effect on neuronal differentiation was seen. Whereas the expression of Alk2 and Alk3 mRNA remained unchanged, the Alk6 mRNA was induced after impaired BMP signaling. After dnAlk3 overexpression, cell survival and astroglial differentiation increased in parallel to augmented Alk6 receptor signaling. We conclude that endogenous BMPs mediate cell survival, astroglial differentiation and the suppression of oligodendrocytic cell fate mainly via the Alk6 receptor in AHP culture.
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| 13. |
- Brederlau, Anke, 1968, et al.
(författare)
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Transplantation of human embryonic stem cell-derived cells to a rat model of Parkinson's disease: effect of in vitro differentiation on graft survival and teratoma formation.
- 2006
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Ingår i: Stem cells (Dayton, Ohio). - : Oxford University Press (OUP). - 1066-5099 .- 1549-4918. ; 24:6, s. 1433-40
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Tidskriftsartikel (refereegranskat)abstract
- Human embryonic stem cells (hESCs) have been proposed as a source of dopamine (DA) neurons for transplantation in Parkinson's disease (PD). We have investigated the effect of in vitro predifferentiation on in vivo survival and differentiation of hESCs implanted into the 6-OHDA (6-hydroxydopamine)-lesion rat model of PD. The hESCs were cocultured with PA6 cells for 16, 20, or 23 days, leading to the in vitro differentiation into DA neurons. Grafted hESC-derived cells survived well and expressed neuronal markers. However, very few exhibited a DA neuron phenotype. Reversal of lesion-induced motor deficits was not observed. Rats grafted with hESCs predifferentiated in vitro for 16 days developed severe teratomas, whereas most rats grafted with hESCs predifferentiated for 20 and 23 days remained healthy until the end of the experiment. This indicates that prolonged in vitro differentiation of hESCs is essential for preventing formation of teratomas.
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| 14. |
- Brodin, G, et al.
(författare)
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Increased smad expression and activation are associated with apoptosis in normal and malignant prostate after castration.
- 1999
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Ingår i: Cancer research. - : American Association for Cancer Research. - 0008-5472 .- 1538-7445. ; 59:11, s. 2731-8
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Tidskriftsartikel (refereegranskat)abstract
- Transforming growth factor (TGF)-beta1 is induced in the prostate after castration and has been implicated in apoptosis of epithelial cells during involution. TGF-beta1-mediated receptor activation induces phosphorylation of Smad2 and Smad3, which form complexes with Smad4, that translocate to the nucleus to regulate transcription of target genes. Smad6 and Smad7 antagonize the action of signal-transducing Smads. We have examined the immunohistochemical expression of different Smad molecules in the epithelium of rat ventral prostate before and after castration, in androgen-sensitive Dunning R3327 PAP prostatic tumor cells from untreated and castrated rats, and after treatment with estrogen. In the ventral prostate, a significant increase of phosphorylated Smad2 (P-Smad2) was observed after castration. In prostatic tumor cells we observed an increased expression of Smad2 and P-Smad2 after treatment. The levels of Smad3 and, in particular, Smad4 were enhanced in the normal ventral prostate, as well as in the tumors after castration. Interestingly, Smad6 and Smad7 expression was also up-regulated in cells with increased Smad2 activation. The staining for Smad2, P-Smad2, Smad3, Smad4, and Smad7 was nuclear in some cells and was present in areas with a large number of apoptotic cells identified by various morphological criteria, formation of apoptotic bodies and, in adjacent sections, by terminal deoxynucleotidyl transferase-mediated nick end labeling assay. Our results suggest that the signal transduction pathway for TGF-beta, leading to apoptosis, is activated in the normal prostate after castration and in the tumor model after castration, without or with estrogen treatment.
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| 15. |
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| 16. |
- Chaudhry, A, et al.
(författare)
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Expression of transforming growth factor b1, b2, b3 in neuroendocrine tumors of the digestive system
- 1994
-
Ingår i: Anticancer Res. ; 14, s. 2085-
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Tidskriftsartikel (refereegranskat)abstract
- Ligand induced activation of the beta-receptor for platelet-derived growth factor (PDGF) leads to activation of Src family tyrosine kinases. We have explored the possibility that the receptor itself is a substrate for Src. We show that Tyr934 in the kinase domain of the PDGF receptor is phosphorylated by Src. Cell lines expressing a beta-receptor mutant, in which Tyr934 was replaced with a phenyalanine residue, showed reduced mitogenic signaling in response to PDGF-BB. In contrast, the mutant receptor mediated increased signals for chemotaxis and actin reorganization. Whereas the motility responses of cells expressing wild-type beta-receptors were attenuated by inhibition of phosphatidylinositol 3'-kinase, those of cells expressing the mutant receptor were only slightly influenced. In contrast, PDGF-BB-induced chemotaxis of the cells with the mutant receptor was attenuated by inhibition of protein kinase C, whereas the chemotaxis of cells expressing the wild-type beta-receptor was less affected. Moreover, the PDGF-BB-stimulated tyrosine phosphorylation of phospholipase C-gamma was increased in the mutant receptor cells compared with wild-type receptor cells. In conclusion, the characteristics of the Y934F mutant suggest that the phosphorylation of Tyr934 by Src negatively modulates a signal transduction pathway leading to motility responses which involves phospholipase C-gamma, and shifts the response to increased mitogenicity.
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| 17. |
- Chavali, Pavithra Lakshminarasimhan, et al.
(författare)
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Cis-regulation of microRNA expression by scaffold/matrix-attachment regions
- 2011
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 39:16, s. 6908-18
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Tidskriftsartikel (refereegranskat)abstract
- microRNAs (miRNAs) spatio-temporally modulate gene expression; however, very little is known about the regulation of their expression. Here, we hypothesized that the well-known cis-regulatory elements of gene expression, scaffold/matrix-attachment regions (MARs) could modulate miRNA expression. Accordingly, we found MARs to be enriched in the upstream regions of miRNA genes. To determine their role in cell type-specific expression of miRNAs, we examined four individual miRNAs (let-7b, miR-17, miR-93 and miR-221) and the miR-17-92 cluster, known to be overexpressed in neuroblastoma. Our results show that MARs indeed define the cell-specific expression of these miRNAs by tethering the chromatin to nuclear matrix. This is brought about by cell type-specific binding of HMG I/Y protein to MARs that then promotes the local acetylation of histones, serving as boundary elements for gene activation. The binding, chromatin tethering and gene activation by HMG I/Y was not observed in fibroblast control cells but were restricted to neuroblastoma cells. This study implies that the association of MAR binding proteins to MARs could dictate the tissue/context specific regulation of miRNA genes by serving as a boundary element signaling the transcriptional activation.
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| 18. |
- Chavali, Pavithra Lakshminarasimhan, et al.
(författare)
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Nuclear orphan receptor TLX induces Oct-3/4 for the survival and maintenance of adult hippocampal progenitors upon hypoxia.
- 2011
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Ingår i: The Journal of biological chemistry. - 1083-351X. ; 286:11, s. 9393-9404
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Tidskriftsartikel (refereegranskat)abstract
- Hypoxia promotes neural stem cell proliferation, the mechanism of which is poorly understood. Here, we have identified the nuclear orphan receptor TLX as a mediator for proliferation and pluripotency of neural progenitors, upon hypoxia. We find an enhanced early protein expression of TLX under hypoxia potentiating sustained proliferation of neural progenitors. Moreover, TLX induction upon hypoxia in differentiating conditions leads to increased proliferation and stem cell like phenotype along with coexpression with neural stem cell markers. Following hypoxia, TLX is recruited to Oct-3/4 proximal promoter, augmenting the gene transcription and promoting progenitor proliferation and pluripotency. Knock-down of Oct-3/4 significantly reduced TLX mediated proliferation, highlighting their interdependence in regulating progenitor pool. Additionally, TLX synergizes with bFGF to sustain cell viability upon hypoxia, since the knock-down of TLX along with the withdrawal of growth factor results in cell death. This can be attributed to the activation of Akt signaling pathway by TLX, the depletion of which results in reduced proliferation of progenitor cells. Cumulatively, the data presented here demonstrate a new role for TLX in neural stem cell proliferation and pluripotency upon hypoxia.
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| 19. |
- Chavali, Pavithra Lakshminarasimhan, et al.
(författare)
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TLX activates MMP-2, promotes self-renewal of tumor spheres in neuroblastoma and correlates with poor patient survival.
- 2014
-
Ingår i: Cell Death & Disease. - : Springer Science and Business Media LLC. - 2041-4889. ; 449:5
-
Tidskriftsartikel (refereegranskat)abstract
- Nuclear orphan receptor TLX (Drosophila tailless homolog) is essential for the maintenance of neural stem/progenitor cell self-renewal, but its role in neuroblastoma (NB) is not well understood. Here, we show that TLX is essential for the formation of tumor spheres in three different NB cell lines, when grown in neural stem cell media. We demonstrate that the knock down of TLX in IMR-32 cells diminishes its tumor sphere-forming capacity. In tumor spheres, TLX is coexpressed with the neural progenitor markers Nestin, CD133 and Oct-4. In addition, TLX is coexpressed with the migratory neural progenitor markers CD15 and matrix metalloproteinase-2 (MMP-2) in xenografts of primary NB cells from patients. Subsequently, we show the effect of TLX on the proliferative, invasive and migratory properties of IMR-32 cells. We attribute this to the recruitment of TLX to both MMP-2 and Oct-4 gene promoters, which resulted in the respective gene activation. In support of our findings, we found that TLX expression was high in NB patient tissues when compared with normal peripheral nervous system tissues. Further, the Kaplan-Meier estimator indicated a negative correlation between TLX expression and survival in 88 NB patients. Therefore, our results point at TLX being a crucial player in progression of NB, by promoting self-renewal of NB tumor-initiating cells and altering their migratory and invasive properties.
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| 20. |
- Egawa-Tsuzuki, Tomoko, et al.
(författare)
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The PDGF B-chain is involved in the ontogenic susceptibility of the developing rat brain to NMDA toxicity.
- 2004
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Ingår i: Experimental neurology. - : Elsevier BV. - 0014-4886. ; 186:1, s. 89-98
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Tidskriftsartikel (refereegranskat)abstract
- Hypoxic-ischemic (H-I) injury to neonatal brains can cause a life-long neuronal deficit because of increased susceptibility in the neonatal period. Excitotoxicity due to overstimulation of the N-methyl-d-aspartate receptor (NMDAR) is assumed to be the basis of the injury. However, the ontogenic profile of the susceptibility does not directly correlate with the levels of NMDAR expression. Platelet-derived growth factor B-chain (PDGF-B) has been reported to protect neurons by suppressing the NMDA-evoked current and translocating the glutamate transporter to the cell membrane. Thus, we assessed the relationship between the susceptibility to H-I injury and the expression of PDGF-B in neonatal rat brain. PDGF-B infusion before and after an intrastriatal NMDA injection significantly reduced the size of the lesions in 7-day-old rats, when they are most susceptible and the neuronal expression of PDGF-B is low. Fourteen-day-old neonatal rats were found to be resistant to NMDA injury, even though NMDARs are expressed at high levels in the brain at this age. Inhibition of PDGF-B protein synthesis by antisense oligodeoxynucleotides increased the size of the NMDA-induced lesions up to 6-fold at postnatal day 14, when PDGF-B is expressed at high levels in neurons. These data suggest that PDGF-B is an important physiological modulator of NMDAR excitability in the developing brain, and that the balance between the expression of NMDAR and PDGF-B partly determines the ontogenic susceptibility to brain injury. Enhancement of the PDGF-B/receptor signal pathway might rescue neonatal brains at risk of H-I injury.
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| 21. |
- Elmi, Muna, 1978, et al.
(författare)
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Mechanism of MASH1 induction by ASK1 and ATRA in adult neural progenitors.
- 2007
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Ingår i: Molecular and cellular neurosciences. - : Elsevier BV. - 1044-7431. ; 36:2, s. 248-59
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Tidskriftsartikel (refereegranskat)abstract
- The molecular mechanisms underlying differentiation and lineage commitment in neural stem cells are just beginning to be understood, however the molecules involved in this process and their functions remain largely unknown. Here we studied the effects and downstream signals of apoptosis signal-regulating kinase 1 (ASK1) together with all-trans retinoic acid (ATRA) on neuronal differentiation in adult hippocampus-derived progenitor (AHP) cells. Following ASK1 over-expression and ATRA treatment in AHPs, a larger number of cells differentiated into neurons and the MASH1 promoter became activated. Analyzing downstream effector molecules of ASK1 or ATRA targeting the MASH1 promoter revealed that the myocyte enhancer factor 2C (MEF2C) mediated ASK1 signalling, while activation of Sp1 was involved in ATRA signalling. Chromatin immunoprecipitation assay on the promoter revealed that ASK1 induced binding of MEF2C and Ca(2+)/calmodulin-dependent kinase II to the MASH1 promoter. Taken together, ASK1 and ATRA activate MEF2C and Sp1, respectively, and up-regulate MASH1 protein expression.
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| 22. |
- Elmi, Muna, 1978, et al.
(författare)
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TLX activates MASH1 for induction of neuronal lineage commitment of adult hippocampal neuroprogenitors.
- 2010
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Ingår i: Molecular and cellular neurosciences. - : Elsevier BV. - 1095-9327 .- 1044-7431. ; 45:2, s. 121-31
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Tidskriftsartikel (refereegranskat)abstract
- The orphan nuclear receptor TLX has been proposed to act as a repressor of cell cycle inhibitors to maintain the neural stem cells in an undifferentiated state, and prevents commitment into astrocyte lineages. However, little is known about the mechanism of TLX in neuronal lineage commitment and differentiation. A majority of adult rat hippocampus-derived progenitors (AHPs) cultured in the presence of FGF express a high level of TLX and a fraction of these cells also express the proneural gene MASH1. Upon FGF withdrawal, TLX rapidly decreased, while MASH1 was intensely expressed within 1h, decreasing gradually to disappear at 24h. Adenoviral transduction of TLX in AHP cells in the absence of FGF transiently increased cell proliferation, however, later resulted in neuronal differentiation by inducing MASH1, Neurogenin1, DCX, and MAP2ab. Furthermore, TLX directly targets and activates the MASH1 promoter through interaction with Sp1, recruiting co-activators whereas dismissing the co-repressor HDAC4. Conversely, silencing of TLX in AHPs decreased beta-III tubulin and DCX expression and promoted glial differentiation. Our results thus suggest that TLX not only acts as a repressor of cell cycle and glial differentiation but also activates neuronal lineage commitment in AHPs.
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| 23. |
- Faigle, Roland, 1977, et al.
(författare)
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ASK1 inhibits astroglial development via p38 mitogen-activated protein kinase and promotes neuronal differentiation in adult hippocampus-derived progenitor cells.
- 2004
-
Ingår i: Molecular and cellular biology. - 0270-7306. ; 24:1, s. 280-93
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms controlling differentiation and lineage specification of neural stem cells are still poorly understood, and many of the molecules involved in this process and their specific functions are yet unknown. We investigated the effect of apoptosis signal-regulating kinase 1 (ASK1) on neural stem cells by infecting adult hippocampus-derived rat progenitors with an adenovirus encoding the constitutively active form of ASK1. Following ASK1 overexpression, a significantly larger number of cells differentiated into neurons and a substantial increase in Mash1 transcription was observed. Moreover, a marked depletion of glial cells was observed, persisting even after additional treatment of ASK1-infected cultures with potent glia inducers such as leukemia inhibitory factor and bone morphogenetic protein. Analysis of the promoter for glial fibrillary acidic protein revealed that ASK1 acts as a potent inhibitor of glial-specific gene transcription. However, the signal transducers and activators of transcription 3 (STAT3)-binding site in the promoter was dispensable, while the activation of p38 mitogen-activated protein kinase was crucial for this effect, suggesting the presence of a novel mechanism for the inhibition of glial differentiation.
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| 24. |
- Faigle, Roland, 1977, et al.
(författare)
-
Opposing effects of retinoid signaling on astrogliogenesis in embryonic day 13 and 17 cortical progenitor cells.
- 2008
-
Ingår i: Journal of neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 106:4, s. 1681-98
-
Tidskriftsartikel (refereegranskat)abstract
- All-trans retinoic acid (RA) is a differentiation factor in many tissues. However, its role in astrogliogenesis has not been extensively studied. Here, we investigated the effect of RA on the regulation of astrogliogenesis at different cortical developmental stages. We prepared rat cortical progenitor cells from embryonic day (E) 13 and E17, which correspond to the beginning of neurogenic and astrogliogenic periods, respectively. Surprisingly, RA promoted astrogliogenesis at E17 but inhibited astrogliogenesis induced by ciliary neurotrophic factor (CNTF) at E13. The inhibitory effect of RA on astrogliogenesis at E13 was not due to premature commitment of progenitors to a neuronal or oligodendroglial lineage. Rather, RA retained more progenitors in a proliferative state. Furthermore, RA inhibition of astrogliogenesis at E13 was independent of STAT3 signaling and required the function of the alpha and beta isoforms of the RA receptors (RAR). Moreover, the differential response of E13 and E17 progenitors to RA was due to differences in the intrinsic properties of these cells that are preserved in vitro. The inhibitory effect of RA on cytokine-induced astrogliogenesis at E13 may contribute to silencing of any potential precocious astrogliogenesis during the neurogenic period.
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| 25. |
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| 26. |
- Funa, Keiko, 1949, et al.
(författare)
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Characterization of platelet-derived growth factor (PDGF) action on a mouse neuroblastoma cell line, NB41, by introduction of an antisense PDGF beta-receptor RNA.
- 1997
-
Ingår i: Cell growth & differentiation : the molecular biology journal of the American Association for Cancer Research. - 1044-9523. ; 8:8, s. 861-9
-
Tidskriftsartikel (refereegranskat)abstract
- We have shown previously that platelet-derived growth factor (PDGF) has trophic effects on dopaminergic neurons in vitro. We now examined a mouse neuroblastoma cell line, NB41, for its response to PDGF and studied their phenotypic characteristics following introduction of an antisense PDGF beta-receptor RNA. NB41 cells produce both PDGF-AA and -BB; however, they carry only PDGF beta-receptors, responding to BB but not to AA. Culturing the cells with PDGF-BB induced mRNA for c-fos and PDGF-beta receptor as well as that of neuron-specific enzyme, tyrosine hydroxylase. In contrast, mRNA of chromogranin A, which is produced by chromaffin cells, decreased. Introduction of an antisense PDGF beta-receptor RNA in NB41 cells completely suppressed neurite extension and cell growth. We compared the PDGF-beta receptor sense and antisense clones for their survival. Following serum withdrawal, NB41 cells showed a DNA ladder, which by an addition of the neurotoxin, 6-hydroxy dopamine (6-OHDA), resulted in a further enhancement of the DNA ladder. The addition of PDGF-BB prior to 6-OHDA rescued cells from undergoing apoptosis, seen as a reduction of the DNA ladder. The antisense clone, regardless of the presence of PDGF-BB in the culture, showed a pronounced DNA ladder after serum withdrawal, which was further enhanced by the addition of 6-OHDA.
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| 27. |
- Funa, Keiko, 1949, et al.
(författare)
-
Regulatory mechanisms for the expression and activity of platelet-derived growth factor receptor.
- 2003
-
Ingår i: Acta biochimica Polonica. - 0001-527X. ; 50:3, s. 647-58
-
Forskningsöversikt (refereegranskat)abstract
- PDGF is one of the most potent serum mitogens, and the signalling mechanism by way of its receptor tyrosine-kinase has been extensively studied since its first purification in 1979. The identification of homology between the simian sarcoma virus oncogene, v-sis, and the B-chain of PDGF, as well as the frequent over-expression of both the ligands and receptors in various tumours and stroma led to the proposal of the PDGF-mediated autocrine and paracrine hypothesis. Consistent with the important roles of PDGF in the growth and survival of cells, the expression and activity of PDGF receptors are tightly controlled by both positive and negative feedback mechanisms at different levels. The deregulation of the control system can result in serious pathological conditions such as chronic inflammation and tumours. Understanding the molecular mechanisms for the regulatory system and the signalling pathway of PDGF is essential in order to find effective therapies in the diseases where PDGF is involved.
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| 28. |
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| 29. |
- Funa, Keiko, 1949, et al.
(författare)
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The Roles of PDGF in Development and During Neurogenesis in the Normal and Diseased Nervous System
- 2014
-
Ingår i: Journal of Neuroimmune Pharmacology. - : Springer Science and Business Media LLC. - 1557-1890 .- 1557-1904. ; 9:2, s. 168-181
-
Forskningsöversikt (refereegranskat)abstract
- The four platelet-derived growth factor (PDGF) ligands and PDGF receptors (PDGFRs), alpha and beta (PDGFRA, PDGFRB), are essential proteins that are expressed during embryonic and mature nervous systems, i.e., in neural progenitors, neurons, astrocytes, oligodendrocytes, and vascular cells. PDGF exerts essential roles from the gastrulation period to adult neuronal maintenance by contributing to the regulation of development of preplacodal progenitors, placodal ectoderm, and neural crest cells to adult neural progenitors, in coordinating with other factors. In adulthood, PDGF plays critical roles for maintenance of many specific cell types in the nervous system together with vascular cells through controlling the blood brain barrier homeostasis. At injury or various stresses, PDGF modulates neuronal excitability through adjusting various ion channels, and affecting synaptic plasticity and function. Furthermore, PDGF stimulates survival signals, majorly PI3-K/Akt pathway but also other ways, rescuing cells from apoptosis. Studies imply an involvement of PDGF in dendrite spine morphology, being critical for memory in the developing brain. Recent studies suggest association of PDGF genes with neuropsychiatric disorders. In this review, we will describe the roles of PDGF in the nervous system, from the discovery to recent findings, in order to understand the broad spectrum of PDGF in the nervous system. Recent development of pharmacological and replacement therapies targeting the PDGF system is discussed.
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| 30. |
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| 31. |
- Hackzell, Anders, 1973, et al.
(författare)
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p73 independent of c-Myc represses transcription of platelet-derived growth factor beta-receptor through interaction with NF-Y.
- 2002
-
Ingår i: The Journal of biological chemistry. - 0021-9258. ; 277:42, s. 39769-76
-
Tidskriftsartikel (refereegranskat)abstract
- We recently reported that c-Myc represses the transcription of platelet-derived growth factor (PDGF) beta-receptor (Izumi, H., Molander, C., Penn, L. Z., Ishisaki, A., Kohno, K., and Funa, K. (2001) J. Cell Sci. 114, 1533-1544). We demonstrate here that the p53 family protein p73alpha represses PDGF beta-receptor transcription essentially by the same mechanism. p73alpha but not p73beta or p53 represses the transcription in concordance with its ability to bind NF-YC and NF-YB. None of other p73 isoforms (i.e. p73beta, p73gamma, p73epsilon), C-terminal deletion mutants of p73alpha, and p53 is able to bind NF-Y with the exception of p63alpha. This finding suggests that the sterile alpha-motif domain present only in p73alpha and p63alpha is the interaction site. For the repression, the N-terminal transactivation domain of p73alpha is also indispensable, arguing for the importance of the activity of p73alpha in the mechanism. p73alpha binds the C-terminal HAP domain of NF-YC previously found to be the interaction site with c-Myc and TBP. Because c-Myc induces and activates p73alpha (Zaika, A., Irwin, M., Sansome, C., and Moll, U. M. (2001) J. Biol. Chem. 276, 11310-11316) and they bind each other (Uramoto, H., Izumi, H., Ise, T., Tada, M., Uchiumi, T., Kuwano, M., Yasumoto, K., Funa, K., and Kohno, K. (2002) J. Biol. Chem. 277, in press), we examined whether the repression by p73 is dependent on c-Myc. However, Myc-null rat fibroblasts are also susceptible to p73alpha-induced repression. Serum stimulation of NIH3T3 cells gradually decreased the amount of endogenous NF-Y binding to the PDGF beta-receptor promoter, whereas NF-YA expression in the nuclear extracts remains unchanged. Our results indicate that serum stimulation induces c-Myc and p73alpha, leading to the down-regulation of PDGF beta-receptor expression by repressing its transcription.
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| 32. |
- Hayashi, Amiko, et al.
(författare)
-
Calcium-dependent intracellular signal pathways in primary cultured adipocytes and ANK3 gene variation in patients with bipolar disorder and healthy controls.
- 2015
-
Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 20, s. 931-40
-
Tidskriftsartikel (refereegranskat)abstract
- Bipolar disorder (BD) is a chronic psychiatric disorder of public health importance affecting >1% of the Swedish population. Despite progress, patients still suffer from chronic mood switches with potential severe consequences. Thus, early detection, diagnosis and initiation of correct treatment are critical. Cultured adipocytes from 35 patients with BD and 38 healthy controls were analysed using signal pathway reporter assays, that is, protein kinase C (PKC), protein kinase A (PKA), mitogen-activated protein kinases (extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK)), Myc, Wnt and p53. The levels of activated target transcriptional factors were measured in adipocytes before and after stimulation with lithium and escitalopram. Variations were analysed in the loci of 25 different single-nucleotide polymorphisms (SNPs). Activation of intracellular signals in several pathways analysed were significantly higher in patients than in healthy controls upon drug stimulation, especially with escitalopram stimulation of PKC, JNK and Myc, as well as lithium-stimulated PKC, whereas no meaningful difference was observed before stimulation. Univariate analyses of contingency tables for 80 categorical SNP results versus diagnoses showed a significant link with the ANK3 gene (rs10761482; likelihood ratio χ2=4.63; P=0.031). In a multivariate ordinal logistic fit for diagnosis, a backward stepwise procedure selected ANK3 as the remaining significant predictor. Comparison of the escitalopram-stimulated PKC activity and the ANK3 genotype showed them to add their share of the diagnostic variance, with no interaction (15% of variance explained, P<0.002). The study is cross-sectional with no longitudinal follow-up. Cohorts are relatively small with no medication-free patients, and there are no 'ill patient' controls. It takes 3 to 4 weeks of culture to expand adipocytes that may change epigenetic profiles but remove the possibility of medication effects. Abnormalities in the reactivity of intracellular signal pathways to stimulation and the ANK3 genotype may be associated with pathogenesis of BD. Algorithms using biological patterns such as pathway reactivity together with structural genetic SNP data may provide opportunities for earlier detection and effective treatment of BD.
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| 33. |
- Imamura, T, et al.
(författare)
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Y box-binding protein-1 binds preferentially to single-stranded nucleic acids and exhibits 3'-->5' exonuclease activity.
- 2001
-
Ingår i: Nucleic acids research. - 1362-4962. ; 29:5, s. 1200-7
-
Tidskriftsartikel (refereegranskat)abstract
- We have previously shown that Y box-binding protein-1 (YB-1) binds preferentially to cisplatin-modified Y box sequences. Based on structural and biochemical data, we predicted that this protein binds single-stranded nucleic acids. In the present study we confirmed the prediction and also discovered some unexpected functional features of YB-1. We found that the cold shock domain of the protein is necessary but not sufficient for double-stranded DNA binding while the C-tail domain interacts with both single-stranded DNA and RNA independently of the cold shock domain. In an in vitro translation system the C-tail domain of the protein inhibited translation but the cold shock domain did not. Both in vitro pull-down and in vivo co-immunoprecipitation assays revealed that YB-1 can form a homodimer. Deletion analysis mapped the C-tail domain of the protein as the region of homodimerization. We also characterized an intrinsic 3'-->5' DNA exonuclease activity of the protein. The region between residues 51 and 205 of its 324-amino acid extent is required for full exonuclease activity. Our findings suggest that YB-1 functions in regulating DNA/RNA transactions and that these actions involve different domains.
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| 34. |
- Ishii, Yoko, et al.
(författare)
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Characterization of neuroprogenitor cells expressing the PDGF beta-receptor within the subventricular zone of postnatal mice.
- 2008
-
Ingår i: Molecular and cellular neurosciences. - : Elsevier BV. - 1095-9327 .- 1044-7431. ; 37:3, s. 507-18
-
Tidskriftsartikel (refereegranskat)abstract
- We report a considerable number of cells in the ventricular and the subventricular zones (SVZ) of newborn mice to stain positive for the PDGF beta-receptor (PDGFRB). Many of them also stained for nestin and/or GFAP but less frequently for the neuroblast marker doublecortin and for the mitotic marker Ki-67. The SVZ of mice with nestin-Cre conditional deletion of PDGFRB expressed the receptor only on blood vessels and was devoid of any morphological abnormality. PDGFRB(-/-) neurospheres showed a higher rate of apoptosis without any significant decrease in proliferation. They demonstrated reduced capacities of migration and neuronal differentiation in response to not only PDGF-BB but also bFGF. Furthermore, the PDGFR kinase inhibitor STI571 blocked the effects of bFGF in control neurosphere cultures. bFGF increased the activity of the PDGFRB promoter as well as the expression and phosphorylation of PDGFRB. These results suggest the presence of the signaling convergence between PDGF and FGF. PDGFRB is needed for survival, and the effects of bFGF in migration and neural differentiation of the cells may be potentiated by induction of PDGFRB.
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| 35. |
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| 36. |
- Ishima, T., et al.
(författare)
-
Abnormal gene expression of BDNF, but not BDNF-AS, in iPSC, neural stem cells and postmortem brain samples from bipolar disorder
- 2021
-
Ingår i: Journal of Affective Disorders. - : Elsevier BV. - 0165-0327. ; 290, s. 61-64
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Brain-derived neurotrophic factor (BDNF) antisense RNA (BDNF-AS) was identified as naturally conserved non-coding antisense RNA that suppresses the transcription of BDNF. Methods: We measured the expression of BDNF mRNA and BDNF-AS mRNA in iPSC and NSC from bipolar disorder (BD) patients and healthy control subjects, and postmortem brain samples such as the corpus callosum, the Brodmann area (BA8), and BA46 from BD patients and age-and sex-matched controls. Results: The expression of BDNF mRNA in iPSC from BD patients (n = 6) was significantly lower than that of control subjects (n = 4) although the expression of BDNF mRNA in NSC from BD patients was significantly higher than that of control subjects. In contrast, there were no changes in the expression of BDNF-AS mRNA in both iPSC and NSC between two groups. The expression of BDNF mRNA in the BA46 from BD patients (n = 35) was significantly lower than that of controls (n = 34) although the expression of BDNF mRNA in the corpus callosum and BA8 was not different between two groups (n = 15). In contrast, there were no changes in expression of BDNF-AS mRNA in the three brain regions between two groups. Interestingly, there were significant positive correlations between BDNF mRNA expression and BDNF-AS mRNA expression in the postmortem brain samples. Limitations: Sample sizes are relatively low. Conclusions: Our data suggest that abnormalities in the expression of BDNF, but not BDNF-AS, play a role in the pathogenesis of BD.
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| 37. |
- Ishisaki, A, et al.
(författare)
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Nuclear factor Y controls the basal transcription activity of the mouse platelet-derived-growth-factor beta-receptor gene.
- 1997
-
Ingår i: European journal of biochemistry. - 0014-2956. ; 246:1, s. 142-6
-
Tidskriftsartikel (refereegranskat)abstract
- To determine the regulatory mechanism of the expression of the mouse platelet-derived growth factor (PDGF) beta-receptor gene, a 1.9-kb 5' flanking genomic fragment was cloned and analyzed. Site-directed mutagenesis of a CCAAT motif, located 60 bp upstream of the transcriptional-start site, completely abolished the promoter activity [Ballagi, A. E., Ishisaki, A., Nelin, J.-O. & Funa, K. (1995) Biochem. Biophys. Res. Commun. 210, 165-1751. The sequence around the intact CCAAT motif was protected by in vitro DNase-I-footprinting analysis. Electrophoresis-mobility-shift assays with anti-[nuclear factor Y(NF-Y)]Ig revealed binding of the NF-Y complex to the CCAAT box. Furthermore, the double-stranded oligonucleotides corresponding to the sequence around the CCAAT motif were conjugated with DNA-affinity magnetic beads. The binding proteins were affinity purified and identified as the NF-Y transcription factor by western blotting. Our results indicate that NF-Y controls the basal transcription activity of the mouse PDGF beta-receptor gene.
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| 38. |
- Ito, Yasuhiro, et al.
(författare)
-
Delta Np73 expression in thyroid neoplasms originating from follicular cells.
- 2006
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Ingår i: Pathology. - : Elsevier BV. - 0031-3025. ; 38:3, s. 205-9
-
Tidskriftsartikel (refereegranskat)abstract
- AIMS: p73, a homologue of p53, is known as a negative regulator of tumour progression. However, delta Np73, an isoform of p73 lacking the NH2-terminal transactivation domain plays an oncogenic role by interfering with the activity of p53 and TA (full-length transactivating isoforms) p73. In this study, we investigated the expression of delta Np73 in human thyroid neoplasms originating from follicular cells. METHODS: We immunohistochemically investigated delta Np73 expression in 223 thyroid neoplasms. Delta Np73 expression level was evaluated as the sum of positivity score and intensity score. RESULTS: Normal follicular cells did not express delta Np73, but 27.3% of follicular adenoma, 85.4% of follicular carcinoma, 99.2% of papillary carcinoma, and 95.7% of anaplastic carcinoma were positive for the transcript. Delta Np73 expression level did not differ between widely invasive and minimally invasive follicular carcinomas. In papillary carcinoma, the level was inversely linked to tumour size, extrathyroid extension, and clinically apparent metastasis. Furthermore, in anaplastic carcinoma, delta Np73 expression level was significantly lower than that in papillary carcinoma. CONCLUSIONS: Our findings indicate that delta Np73 plays a role predominantly in the early phase of papillary carcinoma progression.
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| 39. |
- Izsak, Julia, et al.
(författare)
-
Differential acute impact of therapeutically effective and overdose concentrations of lithium on human neuronal single cell and network function
- 2021
-
Ingår i: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 11
-
Tidskriftsartikel (refereegranskat)abstract
- Lithium salts are used as mood-balancing medication prescribed to patients suffering from neuropsychiatric disorders, such as bipolar disorder and major depressive disorder. Lithium salts cross the blood-brain barrier and reach the brain parenchyma within few hours after oral application, however, how lithium influences directly human neuronal function is unknown. We applied patch–clamp and microelectrode array technology on human induced pluripotent stem cell (iPSC)-derived cortical neurons acutely exposed to therapeutic (<1 mM) and overdose concentrations (>1 mM) of lithium chloride (LiCl) to assess how therapeutically effective and overdose concentrations of LiCl directly influence human neuronal electrophysiological function at the synapse, single-cell, and neuronal network level. We describe that human iPSC-cortical neurons exposed to lithium showed an increased neuronal activity under all tested concentrations. Furthermore, we reveal a lithium-induced, concentration-dependent, transition of regular synchronous neuronal network activity using therapeutically effective concentration (<1 mM LiCl) to epileptiform-like neuronal discharges using overdose concentration (>1 mM LiCl). The overdose concentration lithium-induced epileptiform-like activity was similar to the epileptiform-like activity caused by the GABAA-receptor antagonist. Patch–clamp recordings reveal that lithium reduces action potential threshold at all concentrations, however, only overdose concentration causes increased frequency of spontaneous AMPA-receptor mediated transmission. By applying the AMPA-receptor antagonist and anti-epileptic drug Perampanel, we demonstrate that Perampanel suppresses lithium-induced epileptiform-like activity in human cortical neurons. We provide insights in how therapeutically effective and overdose concentration of lithium directly influences human neuronal function at synapse, a single neuron, and neuronal network levels. Furthermore, we provide evidence that Perampanel suppresses pathological neuronal discharges caused by overdose concentrations of lithium in human neurons.
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| 40. |
- Izsak, Julia, et al.
(författare)
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Robust generation of person-specific, synchronously active neuronal networks using purely isogenic human iPSC-3D neural aggregate cultures
- 2019
-
Ingår i: Frontiers in Neuroscience. - : Frontiers Media SA. - 1662-4548 .- 1662-453X. ; 13
-
Tidskriftsartikel (refereegranskat)abstract
- Reproducibly generating human induced pluripotent stem cell-based functional neuronal circuits, solely obtained from single individuals, poses particular challenges to achieve personalized and patient specific functional neuronal in vitro models. A hallmark of functional neuronal assemblies, synchronous neuronal activity, can be non-invasively studied by microelectrode array (MEA) technology, reliably capturing physiological and pathophysiological aspects of human brain function. In our here presented manuscript, we demonstrate a procedure to generate 3D neural aggregates comprising astrocytes, oligodendroglial cells, and neurons obtained from the same human tissue sample. Moreover, we demonstrate the robust ability of those neurons to create a highly synchronously active neuronal network within 3 weeks in vitro, without additionally applied astrocytes. The fusion of MEA-technology with functional neuronal circuits solely obtained from one individual's cells represent isogenic person-specific human neuronal sensor chips that pave the way for specific personalized in vitro neuronal networks as well as neurological and neuropsychiatric disease modeling.
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| 41. |
- Izsak, Julia, et al.
(författare)
-
TGF-β1 Suppresses Proliferation and Induces Differentiation in Human iPSC Neural in vitro Models
- 2020
-
Ingår i: Frontiers in Cell and Developmental Biology. - : Frontiers Media SA. - 2296-634X. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Persistent neural stem cell (NSC) proliferation is, among others, a hallmark of immaturity in human induced pluripotent stem cell (hiPSC)-based neural models. TGF-β1 is known to regulate NSCs in vivo during embryonic development in rodents. Here we examined the role of TGF-β1 as a potential candidate to promote in vitro differentiation of hiPSCs-derived NSCs and maturation of neuronal progenies. We present that TGF-β1 is specifically present in early phases of human fetal brain development. We applied confocal imaging and electrophysiological assessment in hiPSC-NSC and 3D neural in vitro models and demonstrate that TGF-β1 is a signaling protein, which specifically suppresses proliferation, enhances neuronal and glial differentiation, without effecting neuronal maturation. Moreover, we demonstrate that TGF-β1 is equally efficient in enhancing neuronal differentiation of human NSCs as an artificial synthetic small molecule. The presented approach provides a proof-of-concept to replace artificial small molecules with more physiological signaling factors, which paves the way to improve the physiological relevance of human neural developmental in vitro models.
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| 42. |
- Izumi, H., et al.
(författare)
-
Telomere Function and the G-Quadruplex Formation are Regulated by hnRNP U
- 2019
-
Ingår i: Cells. - : MDPI AG. - 2073-4409. ; 8:5
-
Tidskriftsartikel (refereegranskat)abstract
- We examine the role of the heterogenous ribonucleoprotein U (hnRNP U) as a G-quadruplex binding protein in human cell lines. Hypothesizing that hnRNP U is associated with telomeres, we investigate what other telomere-related functions it may have. Telomeric G-quadruplexes have been fully characterized in vitro, but until now no clear evidence of their function or in vivo interactions with proteins has been revealed in mammalian cells. Techniques used were immunoprecipitation, DNA pull-down, binding assay, and Western blots. We identified hnRNP U as a G-quadruplex binding protein. Immunoprecipitations disclosed that endogenous hnRNP U associates with telomeres, and DNA pull-downs showed that the hnRNP U C-terminus specifically binds telomeric G-quadruplexes. We have compared the effect of telomere repeat containing RNA (TERRA) on binding between hnRNP U and telomeric (Tel) or single- stranded Tel (ssTel) oligonucleotides and found that ssTel binds stronger to TERRA than to Tel. We also show that hnRNP U prevents replication protein A (RPA) accumulation at telomeres, and the recognition of telomeric ends by hnRNP suggests that a G-quadruplex promoting protein regulates its accessibility. Thus, hnRNP U-mediated formation has important functions for telomere biology.
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| 43. |
- Johansson, Erik, et al.
(författare)
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Exogenous introduction of tissue inhibitor of metalloproteinase 2 reduces accelerated growth of TGF-β-disrupted diffuse-type gastric carcinoma.
- 2010
-
Ingår i: Cancer science. - : Wiley. - 1349-7006 .- 1347-9032. ; 101:11, s. 2398-403
-
Tidskriftsartikel (refereegranskat)abstract
- Diffuse-type gastric carcinoma is characterized by rapid progression and poor prognosis. High expression of transforming growth factor (TGF)-β and thick stromal fibrosis are observed in this type of gastric carcinoma. We have previously shown that disruption of TGF-β signaling via introduction of a dominant negative form of the TGF-β type II receptor (dnTβRII) into diffuse-type gastric cancer cell lines, including OCUM-2MLN, caused accelerated tumor growth through induction of tumor angiogenesis in vivo. In the present study, we show that TGF-β induces upregulation of expression of tissue inhibitor of metalloproteinase 2 (TIMP2) in the OCUM-2MLN cell line in vitro, and that expression of TIMP2 is repressed by dnTβRII expression in vivo. Transplantation of the OCUM-2MLN cells to nude mice exhibited accelerated tumor growth in response to dnTβRII expression, which was completely abolished when TIMP2 was coexpressed with dnTβRII. Although the blood vessel density of TIMP2-expressing tumors was only slightly decreased, the degree of hypoxia in tumor tissues was significantly increased and pericytes covering tumor vasculature were decreased by TIMP2 expression in OCUM-2MLN cells, suggesting that the function of tumor vasculatures was repressed by TIMP2 and consequently tumor growth was reduced. These findings provide evidence that one of the mechanisms of the increase in angiogenesis in diffuse-type gastric carcinoma is the downregulation of the anti-angiogenic protein TIMP2.
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| 44. |
- Johansson, Erik, et al.
(författare)
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Nuclear receptor TLX inhibits TGF-beta signaling in glioblastoma
- 2016
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827. ; 343:2, s. 118-125
-
Tidskriftsartikel (refereegranskat)abstract
- TLX (also called NR2E1) is an orphan nuclear receptor that maintains sternness of neuronal stem cells. TLX is highly expressed in the most malignant form of glioma, glioblastoma multiforme (GBM), and is important for the proliferation and maintenance of the stem/progenitor cells of the tumor. Transforming Growth Factor-beta (TGF-beta) is a cytokine regulating many different cellular processes such as differentiation, migration, adhesion, cell death and proliferation. TGF-beta has an important function in cancer where it can work as either a tumor suppressor or oncogene, depending on the cancer type and stage of tumor development. Since glioblastoma often have dysfunctional TGF-beta signaling we wanted to find out if there is any interaction between TLX and TGF-beta in glioblastoma cells. We demonstrate that knockdown of TLX enhances the canonical TGF-beta signaling response in glioblastoma cell lines. TLX physically interacts with and stabilizes Smurf1, which can ubiquitinate and target TGF-beta receptor II for degradation, whereas knockdown of TLX leads to stabilization of TGF-beta receptor II, increased nuclear translocation of Smad2/3 and enhanced expression of TGF-beta target genes. The interaction between TLX and TGF-beta may play an important role in the regulation of proliferation and tumor-initiating properties of glioblastoma cells.
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| 45. |
- Jörnsten, Rebecka, 1971, et al.
(författare)
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Network modeling of the transcriptional effects of copy number aberrations in glioblastoma
- 2011
-
Ingår i: Molecular Systems Biology. - : EMBO. - 1744-4292. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- DNA copy number aberrations (CNAs) are a hallmark of cancer genomes. However, little is known about how such changes affect global gene expression. We develop a modeling framework, EPoC (Endogenous Perturbation analysis of Cancer), to (1) detect disease-driving CNAs and their effect on target mRNA expression, and to (2) stratify cancer patients into long- and short-term survivors. Our method constructs causal network models of gene expression by combining genome-wide DNA- and RNA-level data. Prognostic scores are obtained from a singular value decomposition of the networks. By applying EPoC to glioblastoma data from The Cancer Genome Atlas consortium, we demonstrate that the resulting network models contain known disease-relevant hub genes, reveal interesting candidate hubs, and uncover predictors of patient survival. Targeted validations in four glioblastoma cell lines support selected predictions, and implicate the p53-interacting protein Necdin in suppressing glioblastoma cell growth. We conclude that large-scale network modeling of the effects of CNAs on gene expression may provide insights into the biology of human cancer. Free software in MATLAB and R is provided.
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| 46. |
- Kaneko, Masaharu, et al.
(författare)
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Activity of a novel PDGF beta-receptor enhancer during the cell cycle and upon differentiation of neuroblastoma.
- 2006
-
Ingår i: Experimental cell research. - : Elsevier BV. - 0014-4827. ; 312:11, s. 2028-39
-
Tidskriftsartikel (refereegranskat)abstract
- PDGF acts as an autocrine and paracrine factor in certain tumors through upregulation of the PDGF beta-receptor expression. In order to elucidate the control mechanism for the receptor expression, we have isolated an enhancer from two P1 clones that together contain a 102 kb NotI region covering the entire human PDGFRB gene. They were partially digested with TspI and cloned into the PDGFRB enhancer trap vector to make a library for identification of enhancers. The digested DNA containing enhancer was identified by expression of GFP when transfected in PDGF beta-receptor expressing cells. One of the enhancer clones was further examined by making several deletion mutants in a luciferase vector. This enhancer was most active in neuroblastoma cells, IMR32 and BE2, but less active in hemangioma and in smooth muscle cell lines. Chip assay revealed that SP1, AP2, and GATA2 bound the enhancer in BE2 cells. Their interaction occurred dependently of the cell cycle and synchronously with their binding to the promoter. Transfection of GATA2 alone or with Ets, which binds adjacent to GATA, resulted in differentiation of BE2 cells in parallel with increased PDGF beta-receptor expression. Furthermore, over-expression of the PDGF beta-receptor in BE2 cells induced neurite extension.
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| 47. |
- Korchynskyi, O, et al.
(författare)
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Expression of Smad proteins in human colorectal cancer.
- 1999
-
Ingår i: International journal of cancer. - 0020-7136. ; 82:2, s. 197-202
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Tidskriftsartikel (refereegranskat)abstract
- Escape from transforming growth factor-beta (TGF-beta)-induced inhibition of proliferation has been observed in many tumor cells and may contribute to loss of growth control. Smad proteins have been identified as major components in the intracellular signaling of TGF-beta family members. In this study, we examined the expression of receptor-activated, common-mediator and inhibitory Smads by immunohistochemistry in human colorectal cancers. We found increased expression of receptor-activated Smads in a fraction of the tumor cells, while no immunostaining for Smad2, Smad3 or Smad5 and only occasional staining for Smad1/8 was found in epithelial mucosa of normal colon. No or only weak staining for receptor-activated Smads, common-mediator Smad4 and inhibitory Smads was observed in the tumor stroma. Common-mediator Smad4 and inhibitory Smads were detected in cells of both tumor and normal tissues. We observed a distinct pattern of Smad4 immunostaining of epithelial cells along colon crypts, with high expression in zones of terminal differentiation. Our data show selective up-regulation of receptor-activated Smad proteins in human colorectal cancers and suggest involvement of Smad4 in differentiation and apoptosis of surface epithelial cells of normal crypts.
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| 48. |
- Kumagai, S, et al.
(författare)
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Platelet-derived growth factor and its receptors are expressed in areas of both active inflammation and active fibrosis in inflammatory bowel disease.
- 2001
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Ingår i: The Tohoku journal of experimental medicine. - 0040-8727. ; 195:1, s. 21-33
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study is to clarify in situ expression of platelet-derived growth factor (PDGF) and its receptors in different phases of inflammatory bowel disease (IBD). Tissues samples were obtained from 20 patients with ulcerative colitis (UC) and 29 with Crohn's disease (CD) at surgery. In situ hybridization and immunohistochemistry on frozen sections were performed for PDGF-A and -B and its alpha and beta receptors (alphaR and betaR). The area of active inflammation was infiltrated by abundant polymorphonuclear and mononuclear leukocytes, of which the latter expressed mRNA and proteins of PDGF-A, -B, and -alphaR and mRNA for PDGF-betaR. The area of active fibrosis, characterized by activated fibroblasts/ myofibroblasts, was juxtaposed to ulceration, which is induced as a repair process to tissue destruction. In these areas, activated fibroblasts/myofibroblasts were positive for mRNA and protein of PDGF-A, -B, -alphaR, and -betaR. The expression of PDGF-A, -B, and -alphaR declined significantly in the scar area. Our results suggest that PDGF is not only important as an inducer of fibrosis in the repair phase but also it is involved in the active inflammatory phase possibly as a chemoattractant for mononuclear inflammatory cells.
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| 49. |
- Lange, D, et al.
(författare)
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Autocrine endothelial regulation in brain stem vessels of newborn piglets.
- 1999
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Ingår i: Histology and histopathology. - 0213-3911. ; 14:3, s. 821-5
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Tidskriftsartikel (refereegranskat)abstract
- Vasoactive intestinal peptide (VIP) is known as a potent regulator for the development of the central nervous system (CNS). The neonatal period of brain development is characterised by rapid cellular proliferation in parallel with neuronal differentiation and angiogenesis. We examined the expression of native VIP and the VIP receptor-associated protein by immunohistochemistry as well as the expression of VIP mRNA by in situ hybridisation in the brain stem of newborn piglets. We found both the mRNA and the protein of VIP as well as the VIP receptor-associated protein in endothelial cells of veins, arteries and capillaries in the marginal zone of brain stem tissue sections, especially in pons and mesencephalon, as well as in pial vessels. The coexpression of native VIP, VIP mRNA and the VIP receptor-associated protein within the endothelium suggests the presence of an autocrine loop, which has been detected so far only in neuroblastoma cells. This expression pattern gives evidence to the immaturity of endothelial cells at birth and the presence of an adaptive response in the VIP-regulated system during the change from intra- to extrauterine life.
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| 50. |
- Lange, D, et al.
(författare)
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Expression of TGF-beta related Smad proteins in human epithelial skin tumors.
- 1999
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Ingår i: International journal of oncology. - 1019-6439. ; 14:6, s. 1049-56
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Tidskriftsartikel (refereegranskat)abstract
- Members of the transforming growth factor (TGF)-beta family regulate cell growth and differentiation activating intracellular Smad proteins. Their role in skin and skin tumorigenesis is not well understood. Therefore we investigated the expression of TGF-beta type I receptor (TbetaR-I) and Smad-proteins involved in the TGF-beta-pathway, e.g. Smad2, Smad3, Smad4, Smad6 and Smad7. We examined the effects of TGF-beta1, -beta2, BMP2, BMP7 on five epithelial cell lines in vitro. TGF-beta1-mediated growth inhibition of HaCaT and HSC4 were observed with half maximal effects at approximately 7 pg ml-1 and 20 pg ml-1, respectively. However, malignant HSC2 and A431 cells were unresponsive to TGF-beta1. A differentiation was seen after 5 days in HaCaT and HSC4 cells only. We compared the reactivity with specific antisera against TbetaR-I and Smad proteins among the different skin tumors: seborrheic keratoses (SK), actinic keratoses (AK), basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). There were statistically significant differences of the ratio between the expression in tumor and that in non-tumorous epithelial cells in each tissue specimen. There was a tendency for the lower level of TbetaR-I expression of SCC compared with SK (p=0.08). This was accompanied by the decreased expression of the TbetaR-I. We found a markedly decreased expression of all antigens in BCC. conversion of normal keratinocytes to tumorigenic cells may in part be due to an acquisition of resistance to TGF-beta and loss of expression of intracellular signalling Smad proteins.
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