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- Lindgren, Hanna, et al.
(författare)
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Differential usage of IκBα and IκBβ in regulation of apoptosis versus gene expression
- 2003
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Ingår i: Biochemical and Biophysical Research Communications. - 1090-2104. ; 301:1, s. 204-211
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Tidskriftsartikel (refereegranskat)abstract
- n this study we use the N-substituted benzamides declopramide (3-CPA) and N-acetyl declopramide (Na-3-CPA) to investigate the involvement of the transcription factor NF-κB in the induction of apoptosis and surface immunoglobulin κ (Igκ) expression in the mouse pre-B cell line 70Z/3. We first showed that 3-CPA-induced apoptosis at doses around 500 μM and that the 3-CPA-induced apoptosis could be suppressed by over-expression of the Bcl-2 protein. Na-3-CPA was shown to be non-apoptotic at doses up to 1–2 mM. On the other hand, Na-3-CPA inhibited LPS-induced Igκ expression while 3-CPA had no effect. Further analysis showed that while 3-CPA inhibited breakdown of IκBα, Na-3-CPA inhibited breakdown of IκBβ. In addition, we used a 70Z/3 cell line expressing a dominant negative IκBα (70Z/3ΔNIκBα). The 70Z/3ΔNIκBα cell line was shown to be more sensitive to apoptosis and cytotoxicity induced by 3-CPA as well as by LPS, probably due to a defect in NF-κB rescue mechanism. Taken together, our data implicate distinct roles for IκBα and IκBβ in regulating various NF-κB activities.
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| 5. |
- Lindgren, Hanna
(författare)
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Regulation of lymphocyte activation and death
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- T lymohocytes (T cells) and B lymphocytes (B cells) are important effector cells of the adaptive immune system. In response to infections, B cells are activated and produce antibodies against specific antigens. There are two types of T cells, cytotoxic T cells that kill cells infected with bacteria or viruses, and helper T (Th) cells that help B cells produce antibodies by secreting cytokines as well as by upregulating cell surface molecules. In one part of this study, we investigated the expression of one of these cell surface molecules, the CD40 ligand (CD40L), on activated Th cells. We were able to demonstrate the involvement of a new transcription factor, Egr, in regulation of CD40L expression. In the other part of the study we investigated the effects of a group of compounds, N-substituted benzamides, on signaling pathways and transcription factors involved in T and B cell activation and also in apoptosis. We were able to show that N-substituted benzamides having an extra acetyl group (Na-PA and Na-3-CPA) could inhibit activity of the transcription factors NF-kB and NFAT as well as expression of the CD40L in T cells. Activity of the transcription factor AP-1, as well as transcription of IL-2, was on the other hand increased. We could further show that Na-3-CPA inhibited NF-kB activity in pre-B cells. On the other hand, an N-substituted benzamide lacking the acetyl group but containing an extra chloride (3-CPA) was a potent inducer of apoptosis. We could show that 3-CPA induced apoptosis by two mechanisms. Addition of 3-CPA to pre-B cells induced cytochrome c release from the mitochondria and a subsequent activation of caspase-9. 3-CPA could also induce apoptosis in combination with LPS by inhibition of the NF-kB rescue pathway. Thus, we have in this study defined some of the working mechanisms for N-substituted benzamides in T and B cells at a molecular level.
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- Lundblad, Martin, et al.
(författare)
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A model of L-DOPA-induced dyskinesia in 6-hydroxydopamine lesioned mice: relation to motor and cellular parameters of nigrostriatal function.
- 2004
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Ingår i: Neurobiology of Disease. - : Elsevier BV. - 0969-9961. ; 16:1, s. 110-123
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Tidskriftsartikel (refereegranskat)abstract
- L-DOPA-induced dyskinesia is a major complication of L-DOPA pharmacotherapy in Parkinson's disease, and is thought to depend on abnormal cell signaling in the basal ganglia. In this study, we have addressed the possibility to model L-DOPA-induced dyskinesia in the mouse at both the behavioral and the molecular level. C57BL/6 mice sustained unilateral injections of 6-hydroxydopamine (6-OHDA) either in the medial forebrain bundle (MFB) or in the sensorimotor part of the striatum. Both types of lesion produced a similar degree of forelimb akinesia on the contralateral side of the body. The lowest dose of L-DOPA that could significantly relieve this akinetic deficit (i.e., 6 mg/kg) did not differ between MFB and intrastriatal lesions. The L-DOPA threshold dose for the induction of dyskinesia did however differ between the two lesion types. A daily dose of 6 mg/kg L-DOPA caused MFB lesioned mice to develop abnormal movements affecting orofacial, trunk, and forelimb muscles on the side contralateral to the lesion, whereas a daily dose of 18 mg/kg was required to produce comparable dyskinetic effects in the intrastriatally lesioned animals. The development of abnormal movements was accompanied by a striatal induction of DeltaFosB-like proteins and prodynorphin mRNA, that is, molecular markers that are associated with L-DOPA-induced dyskinesia in both rats and nonhuman primates. We conclude that 6-OHDA lesioned mice exhibit behavioral and cellular features of akinesia and L-DOPA-induced dyskinesia that are similar to those previously characterized in rats. The mouse model of L-DOPA-induced dyskinesia will provide a useful tool to study the molecular determinants of this movement disorder in transgenic mice strains.
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- Olsson, A R, et al.
(författare)
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Mechanism of action for N-substituted benzamide-induced apoptosis.
- 2002
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Ingår i: British Journal of Cancer. - 1532-1827. ; 86:6, s. 971-978
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Tidskriftsartikel (refereegranskat)abstract
- We have analysed the mechanism of action for induction of apoptosis by N-substituted benzamides using declopramide as a lead compound. We show here that declopramide at doses above 250 microM in the mouse 70Z/3 pre-B cell line or in the human promyeolocytic cancer cell line HL60 induced cytochrome c release into the cytosol and caspase-9 activation. The broad spectrum caspase inhibitor zVADfmk and caspase-9 inhibitor zLEDHfmk inhibited apoptosis and improved cell viability when administrated to cells 1 h before exposure to declopramide, whereas the caspase-8 inhibitor zIEDHfmk had less effect. Also, the over expression of Bcl-2 by transfection in 70Z/3 cells inhibited declopramide-induced apoptosis. Prior to the induction of apoptosis, a G(2)/M cell cycle block was induced by declopramide. The cell cycle block was also observed in the presence of broad spectrum caspase inhibitor zVADfmk and in a transfectant expressing high levels of Bcl-2. Furthermore, while p53 was induced in 70Z/3 cells by declopramide, neither the apoptotic mechanism nor the G(2)/M cell cycle block were dependent on p53 activation since both effects were also seen in p53 deficient HL60 cells after addition of declopramide.
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- Silver, Christina, et al.
(författare)
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An extract of Uncaria tomentosa inhibiting cell division and NF-kappaB activity without inducing cell death.
- 2003
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Ingår i: International Immunopharmacology. - : Elsevier BV. - 1878-1705 .- 1567-5769. ; 3:13-14, s. 1889-1900
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Tidskriftsartikel (refereegranskat)abstract
- Previous reports have demonstrated that extracts of the plant Uncaria tomentosa inhibit tumor cell proliferation and inflammatory responses. We have confirmed that C-Med 100®, a hot water extract of this plant, inhibits tumor cell proliferation albeit with variable efficiency. We extend these findings by showing that this extract also inhibits proliferation of normal mouse T and B lymphocytes and that the inhibition is not caused by toxicity or by induction of apoptosis. Further, the extract did not interfere with IL-2 production nor IL-2 receptor signaling. Since there was no discrete cell cycle block in C-Med 100®-treated cells, we propose that retarded cell cycle progression caused the inhibition of proliferation. Collectively, these data suggested interference with a common pathway controlling cell growth and cell cycle progression. Indeed, we provide direct evidence that C-Med 100® inhibits nuclear factor κB (NF-κB) activity and propose that this at least partially causes the inhibition of proliferation.
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