| 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 CD56 expression and increased numbers of CD56+bright cells in the peripheral blood of untreated endometriosis patients
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Problem: Endometriosis is characterized by ectopic implantation of endometrial-like tissue and impaired immuneresponses such as the cytotoxic function of NK cells. NK cells can be divided into two subpopulations where theCD56+bright cells produce more cytokines and have low natural cytotoxicity compared to CD56+dim cells. Themajority (>90%) of circulating NK cells are CD56+dim whereas very few (0-10 %) are CD56+bright.Method of Study: Using flow cytometry, NK cell subpopulations were analyzed in peripheral blood from 21individuals with endometriosis and 12 healthy controls. Furthermore, the NKG2D receptor expression on PBMCswas analyzed in untreated and treated endometriosis patients and controls.Results: We found an increased level of CD56+bright cells in 8 of 21 endometriosis patients. After surgery andhormonal treatment, the levels were normalized to that of controls. In a new cohort, the NKG2D receptorexpression on PBMCs was analyzed, with a lower expression in untreated patients compared to controls andpatients treated by surgery and hormones.Conclusions: Our findings of a dominant CD56+bright NK cell subpopulation in peripheral blood, anddownregulated levels of the NKG2D receptor on PBMCs, may explain the impaired cytotoxic immune functioncausing the persistence of ectopic endometrium in untreated endometriosis patients.
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| 3. |
- Björk, Emma, 1977-
(författare)
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Immunosuppressive mechanisms in endometriosis : a focus on the role of exosomes
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Endometriosis is defined as the presence of endometrial-like tissue outside the uterine cavity. It has been suggested that the aberrant immunological mechanisms that cause dysfunction of immune cells and mediators are involved in the pathogenesis of endometriosis. There is substantial evidence of downregulated NK cell cytotoxicity and changes in inflammatory mediators such as cytokines in endometriosis. This research aimed to elucidate the immunosuppressive mechanisms in endometriosis, focusing on NK cells, the role of cytokines, and exosomes derived from endometriotic tissue.Cytokines are small peptides/proteins used for intercellular communication, and regulate immune-effector functions in health and disease. In Paper I, real-time RT-qPCR and a set of primers and probes for 11 cytokines were used defining cytotoxic Th1, humoral Th2, regulatory Tr1/Th3, and inflammatory cytokine profiles. Cytokine mRNA expression in endometriotic tissue was compared with endometrium, and systemically with peripheral blood mononuclear cells (PBMC) from women with endometriosis and healthy controls. In addition, immunohistochemical staining with monoclonal antibodies was performed to investigate T-regulatory cells in endometriotic lesions. A downregulation of mRNA for cytokines that mediate cytotoxicity and antibody response was found in the endometriotic lesions. At the same time, there was an upregulation of inflammatory and T-regulatory cytokines in the endometriotic lesions, suggesting enhanced local inflammation and priming of an adaptive regulatory response. Consistent with these findings, T-regulatory cells were abundant in the endometriotic lesions. These findings suggest that the ectopic implantation seen in endometriosis may be a consequence of increased inflammation and priming of adaptive T regulatory cells, resulting in impaired cytotoxicity and enhanced immune suppression. Exosomes are nanometer-sized extracellular vesicles of endosomal origin; they are produced by most cells in the body, convey intercellular communication and participate in both normal and pathological processes. Paper II show that endometriotic lesions produce high amounts of exosomes. The exosomes expressed on their surfaces the NKG2D ligands MICA/B and ULBP1-3 and the proapoptotic molecules FasL and TRAIL. These molecules are known as immunosuppressive signatures. Functional experiments were performed to show that these exosomes can downregulate the main activating NK receptor NKG2D on CTL and NK cells, reduce the killing ability of PBMC from healthy donors, and induce apoptosis of activated lymphocytes through the FasL/Fas pathway. The production and secretion of exosomes from the endometriotic tissue may be further enhanced by the vigorous local inflammation at ectopic sites. The results show that endometriotic lesions secrete immunosuppressive exosomes that inhibit cytotoxicity and promote apoptosis of activated immune cells. The exosomes form a “protective shield” around the endometriotic tissue thus promoting their survival.NK cells are cytotoxic cells of the innate immune system. Human NK cells can be divided into two subsets: CD56+bright and CD56+dim. The CD56+dim subset is more naturally cytotoxic, whereas the CD56+bright subset produces more cytokines, but has low natural cytotoxicity. The majority (>90%) of circulating NK cells are CD56+dim, whereas very few (0-10 %) are CD56+bright. In Paper III a higher amount of CD56+bright cells in serum was observed in one third of endometriosis patients compared to healthy controls. The amount of these cells was normalized after treatment with surgery, with or without medical treatment. Untreated patients had a lower expression of NKG2D receptors on their NK cells and CTLs compared to treated patients and healthy controls, which could be due to endometriotic exosomes carrying the NKG2D ligands that downregulate the receptor. Thus, surgery might have a beneficial effect on cytotoxic NK-cell function in endometriosis.Endometriosis is considered a benign disease; however it has many features in common with tumors, and shares multiple microenvironmental hallmarks with cancer, including angiogenesis, immune dysregulation, inflammation, invasion, and metastasis. Paper II shows that endometriotic tissue secretes immunosuppressive exosomes. In Paper IV, exosomes in the peripheral blood of epithelial ovarian cancer (EOC) patients, and the impairment of the NKG2D receptor-ligand system in vivo before and after surgery, were studied. The serum exosomes isolated from the EOC patients carried the NKG2D ligands MICA/B and ULBP1-3. In functional experiments, the EOC exosomes downregulated the expression of the NKG2D receptor, and subdued NKG2D-mediated cytotoxicity in NK cells from healthy donors in a similar manner to the endometriotic exosomes studied in Paper II. In Paper IV, surgery of the primary EOC tumor had a beneficial effect, alleviating the exosome-mediated suppression of NKG2D-mediated cytotoxicity. Thus, exosome-mediated immunosuppression is revealed as a common mechanism of action for immune escape in endometriosis and cancer. The results presented in this thesis provide novel and important insights into the function of the immune system in endometriosis, and give new explanations for why ectopic endometrial tissue persists and proliferates outside the uterine cavity. Furthermore, the immunosuppression in the microenvironment of endometriosis, which has many similarities with the local tumor microenvironment (TME), was investigated with a focus on the role of endometriotic exosomes. Taken together, this thesis contributes to understanding of the pathogenesis of endometriosis, and might be useful in identifying biomarkers for endometriosis and developing new immunomodulatory therapies.
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| 4. |
- Bossér, Ulrika, 1976-
(författare)
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Exploring the complexities of integrating socioscientific issues in science teaching
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Socioscientific issues, SSI, can briefly be described as societal issues in which science plays a role. Dealing with SSI in science education is a means to prepare and empower students for active and responsible participation in a complex, democratic society. The implementation of SSI-based teaching calls for classroom practices in which scientific evidence alongside for example social and ethical perspectives are considered. Discourse-based teaching activities are emphasized as a means to provide opportunities for students to practice negotiations of SSI and explore diverse viewpoints on the issues. Dealing with SSI in science teaching is recognized as a challenging task for science teachers. This thesis aims to provide knowledge to support the implementation of SSI-based science teaching. Three studies involving two upper secondary school science teachers are performed to achieve this aim. The first study makes use of video-stimulated discussions to investigate the two teachers’reflections on their classroom practices while they implement SSI throughout an academic year. The second study utilizes the concept positioning as a tool to identify and describe the ways in which one teacher’s interactions with students during group work make available different parts for the students to play as participants, when dealing with SSI in the classroom. The third study makes use of the concept communicative approach to investigate how the two teachers’ management of classroom discussions sets conditions for the consideration of multiple perspectives relevant to SSI, including the students’ viewpoints. The results provide knowledge useful when making considerations about the design and enactment of teaching activities in relation to specific educational goals. The results suggest that a specific challenge with designing and enacting SSI-based teaching activities is to balance between controlling and directing the teaching activities to promote specific learning goals and providing space for students’ participation and perspectives. The results of employing the analytical tools elucidate how this challenge can play out in classroom practice and contribute with knowledge of the ways in which teachers’ discursive practices play a role in addressing this challenge. Strategies to support teachers’ implementation of SSI-based teaching that take account of teachers’ existing practices are discussed.
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| 5. |
- Idahl, Annika, 1965-
(författare)
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Chlamydia trachomatis as a risk factor for infertility in women and men, and ovarian tumor development
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Chlamydia trachomatis in women is a risk factor for tubal factor infertility and extra uterine pregnancies, but the impact of a C. trachomatis infection on male fertility is unclear. It is also hypothesized that persistent infection with C. trachomatis, or other microorganisms, might initiate/promote ovarian tumor development. The aims of the thesis were to study whether C. trachomatis serum antibodies in women and men had an impact on infertility diagnoses, semen characteristics, pregnancy rates and pregnancy outcomes; furthermore, to explore associations of C. trachomatis, and Mycoplasma genitalium, plasma antibodies with epithelial ovarian cancer and borderline ovarian tumors, as well as the presence of C. trachomatis bacteria, and other microorganisms, in ovarian tissues. Materials and methods: Papers I and II: 244/226 infertile couples were tested for serum C. trachomatis IgG, IgA, IgM and chlamydial Heat Shock Protein 60 (cHSP60) IgG antibodies. C. trachomatis IgG positive couples were also tested for C. trachomatis DNA in a urine sample. The follow-up period was 14-54 months. 244 spontaneously pregnant women were also tested for serum C. trachomatis IgG antibodies. Papers III and IV: Plasma samples from 291 women with epithelial ovarian cancer, borderline ovarian tumors and benign conditions, and plasma samples from 271 healthy controls, were analyzed for C. trachomatis IgG, IgA and cHSP60-1 IgG and M. genitalium IgG antibodies. Ovarian tissues from 186 women with benign ovaries, borderline ovarian tumors and epithelial ovarian cancer, as well as tissues from the contra lateral ovary in 126 women, were analyzed for the presence of C. trachomatis, M. genitalium, Neisseria gonorrhoeae, HPV and the polyoma viruses BKV and JCV with nucleic acid amplification tests. Results: Papers I and II: The prevalence of C. trachomatis IgG antibodies was higher among infertile than fertile women, and there were 9 couples with ongoing C. trachomatis infections. In men, C. trachomatis IgG and IgA antibodies were associated with a reduced likelihood to achieve pregnancy for the couple, as well as lower sperm concentration, reduced sperm motility and vitality, increased teratozoospermia index and the occurrence of leukocytes. C. trachomatis IgG and cHSP60 IgG antibodies in infertile women were associated with tubal factor infertility, but not with reduced pregnancy rates or outcomes. Paper III: cHSP60-1 IgG antibodies were associated with ovarian cancer belonging to the postulated type II pathogenetic pathway when plasma samples obtained more than one year prior to diagnosis were analyzed. M. genitalium IgG antibodies were associated with borderline ovarian tumors; however a statistical type 1 error cannot be excluded. Paper IV: None of the microorganisms studied were found in the ovarian tissue samples. Conclusions: C. trachomatis IgG and IgA antibodies in the man substantially decreases the chances of the infertile couple to achieve pregnancy, and are associated with subtle negative changes in semen characteristics. C. trachomatis IgG and cHSP60 IgG antibodies in the woman are risk factors for tubal factor infertility. Prospective plasma cHSP60-1 IgG antibodies are associated with type II ovarian carcinomas, but C. trachomatis bacteria, or the other microorganisms studied, could not be detected in benign, borderline or malignant ovarian tissues.
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| 6. |
- Idahl, Annika, 1965-, et al.
(författare)
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Chlamydia trachomatis, Mycoplasma genitalium, Neisseria gonorrhoeae, human papillomavirus, and polyomavirus are not detectable in human tissue with epithelial ovarian cancer, borderline tumor, or benign conditions
- 2010
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Ingår i: American Journal of Obstetrics and Gynecology. - : Elsevier BV. - 0002-9378 .- 1097-6868. ; 202:1, s. 71.e1-71.e6
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- OBJECTIVE: We sought to analyze the presence of the microorganisms Chlamydia trachomatis, Mycoplasma genitalium, Neisseria gonorrhoeae, human papillomavirus (HPV), and the polyomaviruses BK virus (BKV) and JC virus (JCV) in ovarian tissues of women with ovarian carcinomas, borderline tumors, and benign conditions. STUDY DESIGN: Ovarian tissue, snap-frozen and stored at -80 degrees C, from 186 women with benign conditions, borderline tumors, and epithelial ovarian cancer, as well as tissue from the contralateral ovary of 126 of these women, were analyzed regarding presence of C trachomatis and N gonorrhoeae (transcription mediated amplification), M genitalium (real-time polymerase chain reaction [PCR]), HPV (PCR), and BKV and JCV (PCR). RESULTS: All the tissue samples studied were found negative for the microorganisms analyzed. CONCLUSION: C trachomatis, M genitalium, N gonorrhoeae, HPV, and the polyomaviruses BKV and JCV are not detectable in ovarian tissues either from women with benign conditions and borderline tumors or from women with ovarian cancer.
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| 7. |
- Israelsson, Pernilla, et al.
(författare)
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Assessment of cytokine mRNA expression profiles in tumor microenvironment and peripheral blood mononuclear cells of patients with high-grade serous carcinoma of the ovary
- 2019
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Ingår i: International Journal of Gynecological Cancer. - : BMJ Publishing Group Ltd. - 1048-891X .- 1525-1438. ; 29, s. A138-A138
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Introduction/Background Tumor establishment, metastatic spreading and poor survival in ovarian cancer is strongly associated with progressive derangement of the patient‘s immune system. Accumulating evidence suggests that immune impairment is influenced by the production and presence of cytokines in the tumor microenvironment.Methodology Cytokine mRNA profiles in tumor tissue and peripheral blood mononuclear cells (PBMC) were analyzed in patients with high grade serous carcinoma (HGSC) of the ovary and compared it to patients with benign ovarian conditions and controls with normal ovaries. Cytokine assessment was done by real-time quantitative RT-PCR and specific primers and probes for 12 cytokines-IFN-γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-15, TNF-α, TNF-β/LTA, TGF-β1, and GM-CSF chosen to distinguish between cytotoxic Th1, humoral Th2, regulatory Th3/Tr1 and inflammatory responses.Results The cytokine mRNA response in the HGSC patients was significantly up regulated compared to patients with benign ovarian conditions and normal ovary controls confirming the immunogenicity of HGSC and implying immune recognition and reaction locally in the tumor microenvironment and systemically in the peripheral blood.There was an up-regulation of inflammatory and inhibitory cytokine mRNA promoting tumor progression, T-regulatory cell priming and T-regulatory cell-mediated immune suppression. In contrast, there was an inability to mount the crucially important IFN gamma response needed for upregulation of the cytotoxic anti-tumor response in the local microenvironment. In addition, systemic IL-4- mediated Th2 response prevailed in the peripheral blood deviating the systemic defense towards humoral immunity.Conclusion Taken together, these results suggest local and systemic cytokine cooperation promoting tumor survival, progression and immune escape. Our study confirms and extends previous investigations and contributes to the evaluation of potential cytokine candidates for diagnostic cytokine mRNA profiles and for future therapeutic interventions based on cytokine inhibition.
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| 8. |
- 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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| 9. |
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| 10. |
- Jonsson, S., et al.
(författare)
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Chlamydia trachomatis and anti-MUC1 antibodies and subsequent risk of high grade serous ovarian cancer : a population-based case-control study in Northern Sweden
- 2019
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Ingår i: International Journal of Gynecological Cancer. - : BMJ Publishing Group Ltd. - 1048-891X .- 1525-1438. ; 29, s. A139-A139
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Introduction/Background Chlamydia trachomatis (C. trachomatis) salpingitis causes inflammatory damage to the fallopian tube, the suggested origin of most high grade serous cancers (HGSC), and could thereby cause initiation and progression of ovarian cancer. Infection with C. trachomatis may stimulate production of MUC1 protein and potentially both increase or decrease anti-MUC1 antibody levels. The aim of this study was to examine if serology indicating past infection with C. trachomatis and anti-MUC1 antibodies in prospective blood samples were associated with HGSC.Methodology In a prospective nested case-control study within the Northern Sweden Health and Disease Study (NSHDS) and the Northern Sweden Maternity Cohort (NSMC), the prevalence of chlamydial and anti-MUC1 antibodies was analyzed in blood samples drawn more than one year prior to diagnosis from 92 women with HGSC and 363 matched controls. Matching factors were age and date at blood draw. Plasma C. trachomatis IgG was analyzed using a MIF-test (Focus Diagnostics), chlamydial HSP60 (cHSP60) and anti-MUC1 IgG were analyzed using ELISA serology (Medac; Thermo-Fisher Scientific). HGSC diagnosis was confirmed by pathology report review.Data were analyzed using Chi-square test, Fisher’s exact test and Mann-Whitney U test. Correlation analysis was done by Spearman’s correlation test. A two-sided P-value less than 0.05 was considered significant.Results The prevalence of C. trachomatis IgG and cHSP60 IgG antibodies, as well as the level of anti-MUC1 IgG in women with HGSC compared with controls were similar (16.3% vs. 17.0%, p=0.867; 27.3% vs 28.5%, p=0.802; median 0.24 vs 0.25, p=0.700). A significant correlation was found between anti-MUC1 IgG and cHSP60 IgG (r=0.169; p< 0.001).Conclusion There were no significant association between chlamydial or anti-MUC1 IgG antibodies and HGSC in this prospective nested case control study.
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