| 1. |
- Björk, Emma, 1977-, et al.
(författare)
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Endometriotic tissue-derived exosomes downregulate NKG2D-mediated cytotoxicity and promote apoptosis : mechanisms for survival of endometriotic tissue at ectopic sites
- 2024
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Endometriosis, affecting 10% of women, is defined as implantation, survival, and growth of endometriumlike/endometriotic tissue outside the uterine cavity, causing inflammation, infertility, pain andsusceptibility to ovarian cancer. Despite extensive studies, its etiology and pathogenesis are poorlyunderstood and largely unknown. The prevailing view is that the immune system of endometriosispatients fails to clear ectopically disseminated endometrium from retrograde menstruation. Exosomes aresmall extracellular vesicles that exhibit immunomodulatory properties. We studied the role ofendometriotic tissue-secreted exosomes in the pathophysiology of endometriosis. Two exosome-mediatedmechanisms known to impair the immune response were investigated: 1) downregulation of NKG2Dmediatedcytotoxicity and 2) FasL- and TRAIL-induced apoptosis of activated immune cells. We showedthat secreted endometriotic exosomes isolated from supernatants of short-term explant cultures carry theNKG2D ligands MICA/B and ULBP1-3; and the proapoptotic molecules FasL and TRAIL on theirsurface, i.e. signature molecules of exosome-mediated immune suppression. Acting as decoys, theseexosomes downregulate the NKG2D receptor, impair NKG2D-mediated cytotoxicity and induce apoptosisof activated PBMC and Jurkat cells through the FasL- and TRAIL pathway. The secreted endometrioticexosomes create an immunosuppressive gradient at the ectopic site, forming a “protective shield” aroundthe endometriotic lesions. This gradient guards the endometriotic lesions against clearance by a cytotoxicattack and creates immunologic privilege by induction of apoptosis in activated immune cells. Takentogether, our results provide a plausible, exosome-based mechanistic explanation for the immunedysfunction and the compromised immune surveillance in endometriosis and contribute with novelinsights into the pathogenesis of this enigmatic disease.
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| 2. |
- Björk, Emma, et al.
(författare)
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Enhanced local and systemic inflammatory cytokine mRNA expression in women with endometriosis evokes compensatory adaptive regulatory mRNA response that mediates immune suppression and impairs cytotoxicity
- 2020
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Ingår i: American Journal of Reproductive Immunology. - : John Wiley & Sons. - 1046-7408 .- 1600-0897. ; 84:4
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Tidskriftsartikel (refereegranskat)abstract
- Problem: Endometriosis is a disease characterized by ectopic implantation of endometrium and impaired immune responses. To explore its pathogenic mechanisms, we studied the local and systemic cytokine mRNA profiles and their role in the immunity of patients with endometriosis and healthy controls.Method of Study: mRNA for eleven cytokines defining cytotoxic Th1, humoral Th2, regulatory Tr1/Th3, and inflammatory cytokine profiles was characterized locally in endometriotic tissue and endometrium, and systemically in PBMCs from women with endometriosis and healthy controls, using real‐time qRT‐PCR. In addition, immunohistochemical stainings with monoclonal antibodies were performed looking for T regulatory cells in endometriotic lesions.Results: We found a downregulation of mRNA for cytokines mediating cytotoxicity and antibody response and an upregulation of inflammatory and T‐regulatory cytokines in the endometriotic tissues and endometrium from the patients with endometriosis, suggesting enhanced local inflammation and priming of an adaptive regulatory response. Consistent with those findings, there was an abundancy of T regulatory cells in the endometriotic lesions.Conclusions: The ectopic implantation seen in endometriosis could be possible as a consequence of increased inflammation and priming of adaptive T regulatory cells, resulting in impaired cytotoxicity and enhanced immune suppression.
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| 3. |
- Israelsson, Pernilla, et al.
(författare)
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Cytokine mRNA and protein expression by cell cultures of epithelial ovarian cancer : Methodological considerations on the choice of analytical method for cytokine analyses
- 2020
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Ingår i: American Journal of Reproductive Immunology. - : John Wiley & Sons. - 1046-7408 .- 1600-0897. ; 84:1
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Tidskriftsartikel (refereegranskat)abstract
- Problem: To get a comprehensive picture of cytokine expression in health and disease is difficult, cytokines are transiently and locally expressed, and protein analyses are burdened by biological modifications, technical issues, and sensitivity to handling of samples. Thus, alternative methods, based on molecular techniques for cytokine mRNA analyses, are often used. We compared cytokine mRNA and protein expression to evaluate whether cytokine mRNA profiles can be used instead of protein analyses.Method of study: In kinetic experiments, cytokine mRNA and protein expression of IL-1 beta, IL-6, IL-8, TNF-alpha, and TNF-beta/LTA were studied using real-time RT-qPCR and Luminex(R) microarrays in the ovarian cancer cell lines OVCAR-3, SKOV-3 and the T-cell line Jurkat, after activation of transcription by thermal stress. In addition, we analyzed IL-6 and IL-8 mRNA and protein in a small number of ovarian cancer patients.Results: Ovarian cancer cells can express cytokines on both mRNA and protein level, with 1-4 hours' time delay between the mRNA and protein peak and a negative Spearman correlation. The mRNA and protein expression in patient samples was poorly correlated, reflecting previous studies.Conclusion: Cytokine mRNA and protein expression levels show diverging results, depending on the material analyzed and the method used. Considering the high sensitivity and reproducibility of real-time RT-qPCR, we suggest that cytokine mRNA profiles could be used as a proxy for protein expression for some specific purposes, such as comparisons between different patient groups, and in defining mechanistic pathways involved in the pathogenesis of cancer and other pathological conditions.
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| 4. |
- Israelsson, Pernilla, 1984-
(författare)
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Mechanisms for immune escape in epithelial ovarian cancer
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Tumors develop mechanisms to subvert the immune system, constituting immune escape. Epithelial ovarian cancer (EOC), the deadliest of all gynecological malignancies, uses a variety of mechanisms to undermine immune surveillance, aiding its establishment and metastatic spreading. Despite progress in oncoimmunology, a lot remains unknown about the cancer-immune system interplay. The aim of this thesis was to study tumor-mediated mechanisms for immune escape in EOC patients, focusing on the role of cytokines and EOC- derived exosomes. Cytokines are key molecules regulating immune effector functions in health and disease. We used real-time RT-qPCR and a set of primers and probes for 12 cytokines, discriminating between different immune responses and compared the cytokine mRNA expression profiles locally in the TME and systemically in peripheral blood immune cells of EOC patients, to women with benign ovarian conditions and women with normal ovaries. The cytokine mRNA expression was in general most prominent in EOC patients, confirming the immunogenicity of EOC. We found significant dominance of inflammatory and immunosuppressive/ regulatory cytokines, known to promote tumor progression by priming and activating T regulatory cell-mediated immune suppression. In contrast, IFN-γ, crucially important for evoking a cytotoxic anti-tumor response, was not upregulated. Instead, a systemic increase of IL-4 prevailed, deviating the immune defense towards humoral immunity. With regard to our cytokine study, we performed comparative analyses of cytokine mRNA versus protein expression in the EOC cell lines OVCAR-3 and SKOV-3. We found that cytokine mRNA signals were universally detected, and in some instances translated into proteins, but the protein expression levels depended on the material analyzed and the method used. Due to the high sensitivity of real-time RT-qPCR, we suggest that cytokine mRNA expression profiles can be used for some instances, such as in studies of mechanistic pathways and in comparisons between patient groups, but cannot replace expression at the protein level. Exosomes are nanometer-sized vesicles of endosomal origin, released by virtually all cells, participating in normal and pathological processes. Like many tumors, EOC is a great exosome producer. We isolated exosomes from EOC ascitic fluid and supernatant from tumor explant cultures to study their effect on the NK cell receptors NKG2D and DNAM-1, involved in tumor killing. We found that EOC exosomes constitutively expressed NKG2D ligands on their surface while DNAM-1 ligand expression was rare and not associated with the exosomal membrane. Consistently, the major cytotoxic pathway of NKG2D-mediated killing was dysregulated by EOC exosomes while the accessory DNAM-1- mediated pathway remained unchanged. Our results provide a mechanistic explanation to the previously made observation that in EOC patients, tumor killing is only dependent on the accessory DNAM-1 pathway. Following these iii iv results, we studied NKG2D-mediated cytotoxicity in vivo in EOC patients before and after surgery. We found that the serum exosomes isolated from EOC patients were able to downregulate the NKG2D receptor and suppress NKG2D-mediated cytotoxicity in NK cells from healthy donors, in a similar way as exosomes from EOC ascites. We also found that surgery of the primary EOC tumor has a beneficial effect on the patients’ anti-tumor cytotoxic immune response. One mechanistic explanation could be a decrease in circulating NKG2D ligand- expressing exosomes, thus improving the cytotoxic NK cell function. In conclusion, our results contribute to the understanding of the mechanisms responsible for tumor immune escape in general, and in EOC patients in particular, and might be useful in developing novel antitumor therapies. Our studies highlight the prevailing immunosuppression in the local TME and the immunosuppressive role of EOC exosomes. Furthermore, they support the notion that cancer surgery is also a way of removing exosome-producing cells and reducing the serum concentration of immunosuppressive exosomes, thus boosting the patients’ cytotoxic anti-tumor response.
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| 5. |
- Israelsson, Pernilla, et al.
(författare)
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NKG2D-mediated cytotoxicity improves after primary surgery for high-grade serous ovarian cancer
- 2023
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Ingår i: American Journal of Reproductive Immunology. - : John Wiley & Sons. - 1046-7408 .- 1600-0897. ; 89:1
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Tidskriftsartikel (refereegranskat)abstract
- Problem: Tumors compromise the patients’ immune system to promote their own survival. We have previously reported that HGSC exosomes play a central role, downregulating NKG2D cytotoxicity. Primary surgery's effect on tumor exosomes and NKG2D cytotoxicity in HGSC patients has not been studied before. The overall objective of this study was to explore the effect of surgery on the exosome-induced impairment of NKG2D cytotoxicity in HGSC.Method of study: Paired pre- and post-operative blood samples were subjected to cell and exosome analyses regarding the NKG2D receptor and ligands, and NKG2D-mediated cytotoxicity. Lymphocytes were phenotyped by immunoflow cytometry. Exosomes, isolated by ultracentrifugation, and characterized by nanoparticle tracking analysis, transmission and immune electron microscopy and western blot were used in functional cytotoxic experiments. HGSC explant culture-derived exosomes, previously studied by us, were used for comparison.Results: HGSC exosomes from patients’ sera downregulated NKG2D-mediated cytotoxicity in NK cells of healthy donors. In a subgroup of subjects, NKG2D expression on CTLs and NK cells was upregulated after surgery, correlating to a decrease in the concentration of exosomes in postoperative sera. An overall significantly improved NKG2D-mediated cytotoxic response of the HGSC patients’ own NK cells in postoperative compared to preoperative samples was noted.Conclusions: Surgical removal of the primary tumor has a beneficial effect, relieving the exosome-mediated suppression of NKG2D cytotoxicity in HGSC patients, thus boostering their ability to combat cancer.
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| 6. |
- Yong-Dae, Gwon, et al.
(författare)
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Rift valley fever virus propagates in human villous trophoblast cell lines and induces cytokine mrna responses known to provoke miscarriage
- 2021
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Ingår i: Viruses. - : MDPI. - 1999-4915. ; 13:11
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Tidskriftsartikel (refereegranskat)abstract
- The mosquito-borne Rift Valley fever (RVF) is a prioritised disease that has been listed by the World Health Organization for urgent research and development of counteraction. Rift Valley fever virus (RVFV) can cause a cytopathogenic effect in the infected cell and induce hyperimmune responses that contribute to pathogenesis. In livestock, the consequences of RVFV infection vary from mild symptoms to abortion. In humans, 1–3% of patients with RVFV infection develop severe disease, manifested as, for example, haemorrhagic fever, encephalitis or blindness. RVFV infection has also been associated with miscarriage in humans. During pregnancy, there should be a balance between pro-inflammatory and anti-inflammatory mediators to create a protective environment for the placenta and foetus. Many viruses are capable of penetrating that protective environment and infecting the foetal–maternal unit, possibly via the trophoblasts in the placenta, with potentially severe consequences. Whether it is the viral infection per se, the immune response, or both that contribute to the pathogenesis of miscarriage remains unknown. To investigate how RVFV could contribute to pathogenesis during pregnancy, we infected two human trophoblast cell lines, A3 and Jar, representing normal and transformed human villous trophoblasts, respectively. They were infected with two RVFV variants (wild-type RVFV and RVFV with a deleted NSs protein), and the infection kinetics and 15 different cytokines were analysed. The trophoblast cell lines were infected by both RVFV variants and infection caused upregulation of messenger RNA (mRNA) expression for interferon (IFN) types I–III and inflammatory cytokines, combined with cell linespecific mRNA expression of transforming growth factor (TGF)-β1 and interleukin (IL)-10. When comparing the two RVFV variants, we found that infection with RVFV lacking NSs function caused a hyper-IFN response and inflammatory response, while the wild-type RVFV suppressed the IFN I and inflammatory response. The induction of certain cytokines by RVFV infection could potentially lead to teratogenic effects that disrupt foetal and placental developmental pathways, leading to birth defects and other pregnancy complications, such as miscarriage.
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