| 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, 1977-, et al.
(författare)
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Endometriotic tissue-derived exosomes downregulate NKg2D-mediated cytotoxicity and promote apoptosis : mechanisms for survival of ectopic endometrial tissue in endometriosis
- 2024
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 213:5, s. 567-576
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Tidskriftsartikel (refereegranskat)abstract
- Endometriosis, affecting 10% of women, is defined as implantation, survival, and growth of endometrium-like/endometriotic tissue outside the uterine cavity, causing inflammation, infertility, pain, and susceptibility to ovarian cancer. Despite extensive studies, its etiology and pathogenesis are poorly understood and largely unknown. The prevailing view is that the immune system of endometriosis patients fails to clear ectopically disseminated endometrium from retrograde menstruation. Exosomes are small extracellular vesicles that exhibit immunomodulatory properties. We studied the role of endometriotic tissue-secreted exosomes in the pathophysiology of endometriosis. Two exosome-mediated mechanisms known to impair the immune response were investigated: 1) downregulation of NKG2D-mediated cytotoxicity and 2) FasL- and TRAIL-induced apoptosis of activated immune cells. We showed that secreted endometriotic exosomes isolated from supernatants of short-term explant cultures carry the NKG2D ligands MICA/B and ULBP1-3 and the proapoptotic molecules FasL and TRAIL on their surface, i.e., signature molecules of exosome-mediated immune suppression. Acting as decoys, these exosomes downregulate the NKG2D receptor, impair NKG2D-mediated cytotoxicity, and induce apoptosis of activated PBMCs and Jurkat cells through the FasL- and TRAIL pathway. The secreted endometriotic exosomes create an immunosuppressive gradient at the ectopic site, forming a “protective shield” around the endometriotic lesions. This gradient guards the endometriotic lesions against clearance by a cytotoxic attack and creates immunologic privilege by induction of apoptosis in activated immune cells. Taken together, our results provide a plausible, exosome-based mechanistic explanation for the immune dysfunction and the compromised immune surveillance in endometriosis and contribute novel insights into the pathogenesis of this enigmatic disease.
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| 3. |
- 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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| 4. |
- 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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| 5. |
- Danielsson, Johanna, et al.
(författare)
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Medical students’ experiences in learning to perform pelvic examinations : a mixed-methods study
- 2021
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Ingår i: International Journal of Medical Education. - Nottingham : Medical Education Unit University of Nottingham. - 2042-6372. ; 12, s. 233-242
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: We aimed to explore learning experiences among medical students learning to perform pelvic examinations and to identify factors that facilitate their training.Methods: A mixed-methods study including a web-based survey and focus group discussions (FGDs) was conducted among medical students who had completed their obstetrics and gynaecology (ObGyn) clerkship. The FGDs were recorded, transcribed and analysed using qualitative content analysis with systematic text condensation. Survey factors were compared using the χ2 test or Fisher's exact test.Results: 160 students (97 female, 61 male, two other) at six universities in Sweden responded to the survey. Two mixed FGDs were conducted. The majority (87%) of the students experienced confidence in performing pelvic examinations, stating that sufficient, repeated training opportunities and support from a clinical tutor were crucial components of the learning experience. Prior to the ObGyn clerkship, negative expectations were more common among male students. The male participants experienced having a disadvantage because of their gender, while female students considered their gender an advantage (p<0.001, N=121, Fisher's Exact Test). The clinical tutor and the use of professional patients (PPs) had a fundamental role in providing learning opportunities by including the student in patient care activities.Conclusions: The importance of the clinical tutor, as well as the use of PPs, are important factors when planning education in pelvic examinations, and this knowledge could be used when educating other intimate examinations during medical school. In addition, similar investigations on students' experience in training other intimate examinations could be considered.
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| 6. |
- Gideonsson, Ida, et al.
(författare)
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Long-term follow-up of tamoxifen treatment and the use of imaging in psammocarcinoma : a case report, review of the literature and discussion of diagnostic and therapeutic challenges
- 2023
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Ingår i: Current Oncology. - : MDPI. - 1198-0052 .- 1718-7729. ; 30:12, s. 10260-10271
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Tidskriftsartikel (refereegranskat)abstract
- Psammocarcinoma (PsC) represents a rare form of low-grade serous tumor of the ovary or peritoneum. Although ovarian cancer generally has a poor prognosis in its late stages, PsC seems to have a more indolent course. We present a patient with a history of unspecific abdominal pain for more than a year, with sudden acute onset of severe inguinal pain. On admission to the hospital, a computed tomography (CT) revealed a pelvic mass of suspected ovarian origin. Radical surgery was attempted but not achieved due to widespread tumor growth. Histopathological evaluation revealed estrogen receptor-positive stage III PsC. Tamoxifen treatment was thus initiated, still maintaining stable disease 10 years later. The patient has undergone extensive radiological work-up, including CT, chest X-ray, 18F-fluoro-deoxy-glucose positron emission tomography (PET)/CT, 99mTc- hydroxymethylene diphosphonate (HDP) bone scintigraphy, 18F-fluoro-thymidine (FLT) PET/CT, Tc-99m depreotide scintigraphy and magnetic resonance imaging. In conclusion, we demonstrate that PsC has characteristic radiological features and different imaging modalities can be suitable in different clinical situations. In contrast to most other ovarian cancers, PsC does not always warrant adjuvant chemotherapy, even in advanced stages. This emphasizes the need for a deeper knowledge of the biological behavior of this rare tumor, to select the optimal treatment strategy.
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| 7. |
- 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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| 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. |
- 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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| 10. |
- Jonsson, Sarah, et al.
(författare)
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Chlamydia trachomatis and Anti-MUC1 Serology and Subsequent Risk of High-Grade Serous Ovarian Cancer : A Population-Based Case-Control Study in Northern Sweden
- 2020
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Ingår i: Translational Oncology. - : Elsevier. - 1944-7124 .- 1936-5233. ; 13:1, s. 86-91
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Chlamydia trachomatis salpingitis causes inflammatory damage to the fallopian tube and could potentially cause initiation and progression of high-grade serous ovarian cancer (HGSC). Furthermore, C. trachomatis infection may stimulate mucin 1 (MUC1) protein production, possibly affecting anti-MUC1 antibody levels. The aim of this study was to examine if serology indicating past infection with C. trachomatis as well as anti-MUC1 production was associated with subsequent risk of HGSC.MATERIALS AND METHODS: In a prospective nested case-control study within the Northern Sweden Health and Disease Study and the Northern Sweden Maternity Cohort, the prevalence of chlamydial and anti-MUC1 antibodies was analyzed in blood samples drawn more than one year before diagnosis from 92 women with HGSC and 359 matched controls. Matching factors were age, date at blood draw, and sampling cohort. Plasma C. trachomatis IgG was analyzed using commercial micro-immunofluorescence test; chlamydial Heat Shock Protein 60 IgG (cHSP60) and anti-MUC1 IgG were analyzed with ELISA technique.RESULTS: The prevalence of C. trachomatis IgG and cHSP60 IgG antibodies, as well as the level of anti-MUC1 IgG was similar in women with HGSC and controls (16.3% vs. 17.0%, P = 0.87; 27.2% vs. 28.5%, P = 0.80; median 0.24 vs. 0.25, P = 0.70). Anti-MUC1 IgG and cHSP60 IgG levels were correlated (r = 0.169; P < 0.001).CONCLUSIONS: The findings of this prospective nested case-control study did not support an association between C. trachomatis infection, as measured by chlamydial serology, or anti-MUC1 IgG antibodies, and subsequent risk of HGSC.
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