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| 2. |
- Vahdat Shariatpanahi, Aida, 1982-
(författare)
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The Importance of Macrophages, Lipid Membranes and Seeding in Experimental AA Amyloidosis
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Amyloidosis is a group of protein misfolding diseases caused by tissue deposition of fibrillary protein aggregates termed amyloid. Amyloid A (AA) amyloidosis is a systemic form of amyloidosis that occurs as a complication of chronic inflammatory diseases, such as rheumatoid arthritis, familial Mediterranean fever and chronic infections, such as tuberculosis. AA amyloid is derived from the precursor protein serum amyloid A and is deposited in several organs preferably kidneys, liver and spleen. AA amyloidosis can be induced in mice by long standing inflammatory stimulation and concurrent administration of tissue extracts of AA amyloid, referred to as amyloid enhancing factor (AEF), reduces the time for amyloid deposition in the marginal zone of the spleen from 5 weeks to 2 days. The general aim of this thesis was to investigate the mechanisms involved in the development of AA amyloid in the mouse model of AA amyloidosis.Amyloid was induced in inflamed mice by injection of AEF and amyloid toxicity to splenic macrophages was investigated. We found that the marginal zone macrophages were very sensitive to amyloid formation and increasing amyloid load caused progressive depletion of these cells, whereas red pulp macrophages and metallophilic marginal zone macrophages appeared unaffected. To clarify the role of splenic macrophages in amyloidogenesis, macrophages were depleted by clodronate containing liposomes. We displayed that in the absence of splenic macrophages, especially marginal zone macrophages, amyloid formation was delayed implying a crucial role of macrophages in amyloid formation.The effect of lipid membranes on amyloid formation was studied and we showed that liposomes exhibited an amyloidogenic effect in inflamed mice although not as powerful as AEF. Following the fate of the liposomes, we showed that liposomes were rapidly cleared by uptake in the spleen and liver and colocalized with lysosomes. A tentative mechanism might be that accumulation of liposomes in lysosomes interfere with the SAA degradation process facilitating amyloid formation.Finally the conformational properties of two AEF (AEF1 and AEF2) preparations were studied using conformation sensitive luminescent-conjugated oligothiophenes (LCOs). We found that AEF1 and AEF2 displayed significantly different ultrastructure as well as conformation and consequently induced different cytotoxicity in vitro. Inducing amyloid formation in inflamed mice by AEF1 and AEF2 revealed that the polymorph of the amyloid aggregates was replicated in vivo.In summary, the results obtained in this thesis indicate an important role for macrophages for the formation of amyloid. The existence of amyloid strains has long been an in vitro finding, but the finding that AEF ultrastructure drives the morphology of newly formed amyloid in vivo opens up for new studies that can help us to understand the formation of homologous and heterologous fibrils. Thus, the fundamental mechanisms of various amyloid diseases are similar and the results presented in the thesis can increase the understanding of other amyloid diseases.
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- Dabrosin, Charlotta, 1961-, et al.
(författare)
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Decreased secretion of Cathepsin D in breast cancer in vivo by tamoxifen : Mediated by the mannose-6-phosphate/IGF-II receptor?
- 2004
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Ingår i: Breast Cancer Research and Treatment. - 0167-6806 .- 1573-7217. ; 85:3, s. 229-238
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Tidskriftsartikel (refereegranskat)abstract
- The lysosomal protease Catliepsin D (Cath D) is associated with increased invasiveness and metastasis in breast cancer. Both estrogen and tamoxifen have been reported to increase Cath D, which seems to contradict the efficacy of tamoxifen as an adjuvant for estrogen dependent breast cancer. Cath D is bioactive in the extracellular space but very little is known about hormonal regulation of secreted Cath D in vivo. In this study we used microdialysis to sample the extracellular fluid in estrogen receptor positive MCF-7 tumors in nude mice. We show that tamoxifen in combination with estradiol decreased secreted Cath D compared with estradiol treatment only in solid tumors in situ. Cell culture of MCF-7 cells revealed that estradiol and tamoxifen increased intracellular proteolytic activity of Cath D in a similar fashion whereas secretion of Cath D was increased by estradiol and inhibited by tamoxifen. Immunofluorescence showed that estradiol located Cath D to the cell surface, while tamoxifen accumulated Cath D to dense lysosomes in perinuclear regions. Moreover, tamoxifen increased the intracellular transporter of Cath D, the mannose 6-phosphate/IGF-II receptor (M6P/IGF2R). In contrast, estradiol decreased the levels of this receptor. Thus, secretion of Cath D is hormone dependent and may be mediated by altered expression of the M6P/IGF2R. Our results highlight the importance of measurements of proteins in all compartments where they are biological active and show that microdialysis is a viable technique for sampling of Cath D in vivo.
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| 4. |
- Dabrosin, Charlotta, 1961-, et al.
(författare)
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Variability of glutathione during the menstrual cycle - Due to estrogen effects on hepatocytes?
- 2004
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Ingår i: Free Radical Biology & Medicine. - : Elsevier BV. - 0891-5849 .- 1873-4596. ; 36:2, s. 145-151
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Tidskriftsartikel (refereegranskat)abstract
- Oxidative stress and alterations in the antioxidative defense system may be involved in carcinogenesis. We have previously shown that the levels of glutathione (GSH) in vivo in both breast tissue and subcutaneous fat were higher in the luteal phase compared with the follicular phase, suggesting an overall increase in GSH. This result was confirmed in the present study. Moreover, we exposed normal breast tissue in vivo, breast epithelial cells in vitro, and hepatocytes in culture to ovarian hormones. We found that local perfusion with estradiol, using microdialysis, in normal human breast tissue did not alter the local GSH levels in vivo. In vitro, treatment with estradiol and progesterone of normal human breast epithelial cells did not alter GSH levels. However, levels of GSH in hepatocytes were after 8 h estradiol exposure initially decreased, 76.6 ± 5% of control cells, p < .05, whereas 20 h exposure more than doubled GSH, 209 ± 26% compared with control cells, p < .01. Progesterone had no additional effect. Exposure of hepatocytes to estradiol increased the cellular content of γ-glutamylcysteine synthetase, the rate-limiting enzyme in GSH synthesis. In conclusion we suggest that estradiol affects the GSH homeostasis mainly by effects on hepatocytes, whereas local production in the breast is unaffected by estradiol.
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| 5. |
- Danielsson, Olof, et al.
(författare)
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Apoptosis in idiopathic inflammatory myopathies with partial invasion; a role for CD8(+)cytotoxic T cells?
- 2020
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Ingår i: PLOS ONE. - San Francisco, CA, United States : PUBLIC LIBRARY SCIENCE. - 1932-6203. ; 15:9
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Tidskriftsartikel (refereegranskat)abstract
- Polymyositis and inclusion body myositis are idiopathic inflammatory myopathies, with a pathology characterized by partial invasion of non-necrotic muscle fibres by CD8(+)cytotoxic T-cells, leading to fibre degeneration. Although the main effector pathway of CD8(+)T-cells is to induce apoptosis of target cells, it has remained unclear if apoptosis occurs in these diseases, and if so, if it is mediated by CD8(+)T-cells. In consecutive biopsy sections from 10 patients with partial invasion, muscle fibres and inflammatory cells were assessed by immunohistochemistry and apoptotic nuclei by the TUNEL assay. Analysis of muscle fibre morphology, staining pattern and quantification were performed on digital images, and they were compared with biopsies from 10 dermatomyositis patients and 10 controls without muscle disease. Apoptotic myonuclei were found in muscle with partial invasion, but not in the invaded fibres. Fibres with TUNEL positive nuclei were surrounded by CD8(+)T-cells, granzyme B(+)cells and macrophages, but lacked FAS receptor expression. In contrast, apoptotic myonuclei were rare in dermatomyositis and absent in controls. The findings confirm that apoptosis occurs in idiopathic inflammatory myopathies and support that it is mediated by CD8(+)cytotoxic T- cells, acting in parallel to the process of partial invasion.
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| 6. |
- Duvetorp, Albert, 1980-
(författare)
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Different Aspects of Psoriasis : Comorbidity, Comedication and Disease Biomarkers
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Psoriasis is a common heterogeneous inflammatory disease with its predominant manifestation occurring in the skin. The impact of this disease, however, extends far beyond the skin surface. During the last decades, mounting scientific evidence of psoriasis disease impact on quality of life, stigmatization and comorbidity has led to the predominant view that psoriasis care needs a holistic approach. Epidemiological research is needed to visualize the greater picture whereas research on disease pathomechanisms can provide answers to disease evaluation challenges, facilitate development of new treatments, and provide insights into mechanistical bridges explaining comorbidity occurrence. In study I of this thesis, serum S100A8/A9 was evaluated as a possible biomarker of psoriasis skin disease activity. Dramatic reductions in S100A8 and S100A9 and S100A8/A9 heterocomplex levels were found in lesional psoriasis skin after NB-UVB treatment without any significant reduction occurring in serum. Study II was designed as a retrospective, cross-sectional population study including the adult population of the county of Jönköping. The odds of having pharmacologically treated depression among individuals with psoriasis was compared to the odds of the background population. Psoriasis was associated with an elevated depression risk. Depression was more prevalent among women (both in the background population and among individuals with psoriasis). Young age was associated with higher odds for depression among individuals with psoriasis. Study III was based on the same study population as study II. In this study the comedication burden of individuals with psoriasis was compared to the background population. Comedication assessed were prescription drugs used to treat comorbidity associated with psoriasis in previous scientific publications. Patients with psoriasis were found to have a high comedication burden. Patients receiving systemic treatment for psoriasis had a higher number of different dispensed drugs suggesting that severe disease implies a higher risk of comorbid disease. Study IV was an exploratory study assessing numerous potential biomarkers for psoriasis disease activity. Extensive Luminex analysis of skin and serum samples collected during study I was performed. No serum mediator (potential biomarker of disease activity) showed a significant change after NB-UVB (following correction for multiple testing). In skin, NB-UVB had effects on mediators of the Th17 pathway and multiple chemokines but also previously undescribed or less explored disease mediators. Study II and III suggest that comorbidity and its comedication is common among Swedish psoriasis patients in contact with the health care system. This research reinforces the perception that a holistic approach is needed when treating patients with psoriasis. Behind the failure to identify a biomarker for skin disease activity in study I and IV lurks the questions to how, if or when inflammation in the skin affects systemic inflammation and in extension comorbid disease.
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| 7. |
- Eriksson, Ida, 1985-
(författare)
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Dealing with damaged lysosomes : Impact of lysosomal membrane stability in health and disease
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The lysosome is the main unit for degradation and plays important roles in various cellular processes, such as nutrient sensing, cholesterol regulation and cell death. Consequently, altered lysosomal function contributes to, or even causes, several diseases. Lysosomal membrane permeabilization (LMP) and release of lysosomal content to the cytosol can induce cell death, and is implicated in inflammation and neuronal decline in several neurodegenerative diseases. It has also emerged as a potential target in cancer therapy. Due to the detrimental effects of LMP, cells harbor several mechanisms to protect and prevent lysosomal membrane damage. The aim of this thesis was to elucidate how lysosomal membrane stability and repair mechanisms affect cell death and survival. We find that lysosomal cholesterol is upregulated in response to an increased load of reactive oxygen species in a Parkinson’s disease cell model, and that augmented cholesterol protects from LMP. However, cholesterol also induces accumulation of α-synuclein and inhibits lysosome-mediated degradation, which can destabilize the lysosomal membrane and accelerate the course of disease. Further, we demonstrate that lysosomal membrane damage is counteracted by a calcium-dependent repair mechanism to prevent LMP. Lysosomes damaged beyond repair are instead sequestered in an autophagosome and degraded by intact lysosomes in a process called lysophagy. As a result, small vesicles containing lysosomal membrane proteins are generated, which we believe are used to restore lysosomal function. We show that malignant cells are more sensitive to LMP, and that they differ in their activation of damage-response mechanisms compared to normal cells. Moreover, in malignant cells, the intracellular position of the lysosomes determines the susceptibility to lysosomal damage. Peripherally located lysosomes are less sensitive, and by relocating lysosomes to the perinuclear area in the cell, we can sensitize lysosomes to LMP induction. In summary, this thesis demonstrates the importance of damage-response mechanisms to protect from lysosomal membrane damage and maintain cellular function. It also indicates that targeting of lysosomal stability and repair is a potential therapeutic strategy in both neurodegenerative diseases and in cancer.
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| 8. |
- Garvin, Stina, 1977-, et al.
(författare)
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Resveratrol induces apoptosis and inhibits angiogenesis in human breast cancer xenografts in vivo
- 2006
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Ingår i: Cancer Letters. - : Elsevier BV. - 0304-3835 .- 1872-7980. ; 231:1, s. 113-122
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Tidskriftsartikel (refereegranskat)abstract
- Resveratrol, a polyphenol found in grapes and wine, is considered a potential cancer chemopreventive agent. Resveratrol has been shown to induce transcription via both ERα and ERβ. We observed significantly lower tumor growth, decreased angiogenesis, and increased apoptotic index in ERα- ERβ+ MDA-MB-231 tumors in resveratrol-treated nude mice compared with controls. In vitro we found a significant increase in apoptosis in resveratrol-treated MDA-MB-231 cells in addition to significantly reduced extracellular levels of VEGF. This study supports the potential use of resveratrol as a chemotherapeutic agent in breast cancers. © 2005 Elsevier Ireland Ltd. All rights reserved.
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| 9. |
- Gati, Istvan, 1954-, et al.
(författare)
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Effects of inhibitors of the arachidonic acid cascade on primary muscle culture from a Duchenne muscular dystrophy patient
- 2007
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Ingår i: Prostaglandins, Leukotrienes and Essential Fatty Acids. - : Elsevier BV. - 0952-3278 .- 1532-2823. ; 77:3-4, s. 217-223
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to elucidate the mechanisms of action for potential targets of therapeutic intervention related to the arachidonic acid cascade in muscular dystrophy. Primary cultures from a Duchenne patient were used to study the expression of dystrophin-1, utrophin, desmin, neonatal myosin heavy chain (MHCn) and Bcl-2 during inhibition of phospholipase A2 (PLA2), cyclooxygenase (COX) and lipoxygenase (LOX). Hypo-osmotic treatment was applied in order to trigger Ca2+ influx and PLA2 activity. Inhibition of PLA2 and LOX with prednisolone and nordihydroguaiaretic acid (NDGA) caused a semi-quantitative increase of utrophin and Bcl-2-, and a dose-dependent, quantitative increase of desmin expression, an effect that was augmented by hypo-osmotic treatment. Our results indicate that LOX inhibitors, similarly to corticosteroids, can be beneficial in the treatment of muscular dystrophies. © 2007 Elsevier Ltd. All rights reserved.
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