| 1. |
- Asfaw Idosa, Berhane, 1977-
(author)
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Inflammasome polymorphisms and the Inflammatory Response to Bacterial Infections
- 2016
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Doctoral thesis (other academic/artistic)abstract
- NLRP3 inflammasome; a key component of the innate immune system, can be activated by a number of pathogens and other threats of the body. Activation of the NLRP3 inflammasome triggers caspase-1 mediated maturationof IL-1β and IL-18. Polymorphisms Q705K and C10X are two gene variants of the NLRP3 inflammasome that combined or per se have been associated with higher risk and severity of chronic inflammation and excessive production of IL-1β. Host genetic factors have been found an important determinants of susceptibility of infectious diseases and disease outcome. The aims of this thesis were to investigate the association between polymorphisms Q705K and C10X with bacterial infections and the inflammatory response, moreover to determine the inflammasome activation state in healthy carriers of these polymorphisms. The data of the thesis show higher levels of IL-1β and IL-33 in healthy carriers of combined polymorphisms of Q705K and C10X as compared to non-carrier controls. This may provide individuals with combined polymorphisms a more robust innate immune response against pathogens, but could also lead to the onset of chronic inflammation, and excessive inflammation during acute infection. In addition, individuals with C10X polymorphism per se showed association with the presence of bacteremia as compared withhealthy blood donors. No association was found in severely ill patients with negative blood culture bottle. In addition, the results show that LOS of N. meningitidis is responsible for the priming and activating steps of the inflammasome. The non-LOS components were found to contribute to the priming step. A higher inflammatory response to N. meningitidis was found in individuals who were non-carriers of the polymorphisms than individuals with the Q705K and C10X per se or combined regardless of the strain of bacteria. Taken together, the gene variations of the NLRP3 inflammasome are of importance in explaining inter-individual variation in susceptibility to infectious diseases.
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| 2. |
- Baban, Bayar, 1973-
(author)
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Colorectal cancer and surgery : Insights into insulin resistance and inflammatory markers
- 2024
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Doctoral thesis (other academic/artistic)abstract
- The art of surgery has progressively extended from the realm of anatomy to encompass physiology and beyond, in search of further refinement and optimal recovery. Integral to this is a deeper understanding of the body’s essential metabolic and inflammatory responses to surgical trauma.This thesis aims to provide insights into the intricate interplay between insulin resistance, inflammation and surgical interventions in colorectal cancer patients, as each has an influence on postoperative recovery. Particular emphasis is placed on the role of inflammasomes – central mediators of the innate immune response, adept at detecting and responding to a diverse range of triggers, yet insufficiently explored in these specific contexts.Study I is a comparative analysis of the hyperinsulinemic–euglycaemic clamp and homeostatic model assessment (HOMA) in determining postoperative insulin resistance in 113 patients undergoing various elective surgeries. The findings establish the clamp as the accurate method, detecting key physiological distinctions missed by HOMA.Study II, an exploratory case–control study, assesses insulin sensitivity and inflammatory markers in 20 colorectal cancer patients compared to 10 matched healthy controls. Results indicate insulin resistance, reduced inflammasome activity in circulating immune cells and elevated systemic IL-1β and IL-6 levels in patients.Study III, a pilot exploratory study of 17 patients from Study II, assesses the impact of surgical technique, open versus minimally invasive surgery, on postoperative insulin resistance and inflammation in colorectal cancer resections. It indicates a differential inflammatory response with higher levels in open surgeries, yet a consistent degree of insulin resistance across both surgical techniques.Study IV explores the perioperative temporal sequencing of inflammation and inflammasome action in 18 patients from Study II undergoing elective colorectal cancer resections. It points to a more immediate and pronounced inflammatory response in open surgery compared to minimally invasive surgery, though both techniques show reduced intraoperative caspase-1 activity.In conclusion, the hyperinsulinemic euglycaemic clamp is the accurate method in determinations of postoperative insulin resistance. Patients with colorectal cancer, in comparison to matched healthy controls, exhibit insulin resistance and higher levels of inflammation, but decreased inflammasome (caspase-1) activity in circulating immune cells. Finally, colorectal cancer resections induce both insulin resistance and inflammation; however, the surgical technique utilized only significantly affects the latter, with generally higher inflammatory / inflammasome responses in open surgery.
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| 3. |
- Herring, Matthew, 1982-
(author)
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To be or not to be : investigating the dynamics of the inflammasome
- 2024
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Doctoral thesis (other academic/artistic)abstract
- Inflammasomes are multiprotein complexes that form in response to microbial and host-derived substances, leading to maturation and release of interleukin-1β and -18 and pyroptosis. The most extensively investigated inflammasome is the NLRP3 inflammasome, the formation and activation of which requires two distinct signals, an initial priming signal, and a second activation signal. Assessment of inflammasome activation is performed by measuring one or more readouts, such as ASC-speck formation, caspase-1 activation, cytokine release and LDH leakage from pyroptotic cells. The aims of this thesis are to examine the effects of inflammasome triggers on cell-morphological features in THP-1 cells, using a Cell Painting assay, and investigate the dynamics of inflammasome readouts.The results demonstrate that biologically relevant morphological features, both common between triggers and specific to individual triggers, can be obtained in human THP-1 macrophages. Moreover, NLRP3 specific cellular features can be identified. Furthermore, our results suggest that readouts downstream of inflammasome formation are dynamically regulated in a trigger-dependent fashion. We demonstrate that, not only are temporal associations between readouts distinct with different triggers, but that populations of ASC-specks with different life times may be formed in response to the same trigger. In addition, utilizing several PDAC cell lines, we show that basal NLRP3 inflammasome capabilities are highly heterogenous between cell lines.These results demonstrate the applicability of Cell Painting in immune cells and inflammasome research, and reveal a dynamic capability of the NLRP3 inflammasome that has previously, largely remained unexplored.
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| 4. |
- Hylén, Ulrika, 1977-
(author)
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Immunopsychiatry from a transdiagnostic perspective : the immunometabolic interplay
- 2022
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Doctoral thesis (other academic/artistic)abstract
- Background/Objective: Psychiatric disorders are common and they significantly impact quality of life. It has been proposed that inflammatory processescontribute to the emergence of psychiatric disorders. In addition to inflammation, disturbances in metabolic pathways have been seen in individuals with various psychiatric disorders. At the interface between inflammation and metabolism stands the Nod-like receptor 3 (NLRP3) inflammasome, which is anintracellular protein complex responsible for cleaving members of the interleukin-1(IL-1) to their active forms. The overall aim of this thesis project was tounderstand the interplay between metabolism and inflammation in a transdiagnostic cohort of individuals with severe psychiatric disorders.Methods: Patients with severe psychiatric disorder (n=39) and age- and sexmatched healthy controls (n=39) were included in the studies. Psychiatric diagnoses, comorbidities, severity, and functioning were measured using a numberof validated assessment scales. Biological parameters, such as circulating immune markers, gene expression, and metabolites were analyzed using electrochemiluminescence immunoassay, qPCR, and UHPLC-MSMS, respectively. Results: The results revealed that in individuals with psychiatric disorders, immune cells were primed in regard to the NLRP3 inflammasome, with elevatedinflammasome-related cytokine levels, regardless of diagnosis. In addition, positive metabolic inflammasome regulators, such as lactic acid, serine, and glutamine were significantly higher in the patients; the main metabolic pathwaysthat were affected included arginine and proline metabolism and tryptophan metabolism. A number of these parameters also correlated with the patients’ disease severity. Lastly, the patients as a group displayed transdiagnosticchanges in immune–lipid pathways. In particular, strong associations could beobserved between two triglycerides and one ether phospholipid, with the inflammatory markers osteopontin and IL-1Ra.Conclusion: Severe psychiatric disorders are associated with changes in the inflammasome system and its corresponding cytokines, as well as with metabolicdysregulation. The data indicate that, while these systems are known to be associated, their interplay seems limited to relatively few inflammatory mediatorsand metabolites in this patient group. Lastly, while large overlaps were seen between different primary diagnoses, unifying, transdiagnostic patterns of inflammatory and metabolic dysregulation were weak; further studies with a largercohort are needed to examine this issue.
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| 5. |
- Klasson, Maria, 1977-
(author)
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Cobalt in the hard metal production industry : exposure via inhalation and skin and the inflammatory response in human keratinocytes
- 2020
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Doctoral thesis (other academic/artistic)abstract
- Cobalt is a strong sensitizer and can cause contact allergy upon both direct contact or from airborne exposure on the skin. In the skin, keratinocytes are the first cells to come in contact with the metal and will react and respond to the danger by triggering an alarm system resulting in an inflammatory response in the skin. Keratinocytes have been shown to produce IL-1β, which is one of the most potent inflammatory agents in our body and is associated with a variety of diseases.The aims of this thesis was to investigate cobalt air concentrations for different particle fractions for possible use as proxies for other article measures and to examine if cobalt skin and inhalable air exposure contributes to uptake. Also, to investigate the effect of cobalt on cultured human keratinocyte cell viability, pro-inflammatory cytokine/chemokine release and NLRP3 inflammasome activation using cells cultured at low or high calcium (the latter yielding a more differentiated cell type).Air exposure to cobalt was found in all departments and for all work tasks in the hard metal production facility and exposures were in general below the Swedish OEL for inhalable cobalt. The highest exposure levels were found in the powder production department and for laboratory and furnace work. Good correlations for the mass based measures enable us to use the findings for future references. When personal inhalable air levels of cobalt, cobalt skin levels skin and biological monitoring of cobalt in blood were analysed, the skin exposure was determined to be import as a route of uptake. Skin exposure to cobalt in the hard metal industry, could further affect the total uptake in the same order of magnitude as air exposure. In vitro investigations of cobalt using the human keratinocyte cell line HaCaT, showed that CoCl2 triggered an alarm system in cells where the proinflammatory cytokines/chemokines IL-6, CXCL8 and CCL2, known to be involved in skin inflammation, were secreted in a time- and dosedependent manner. Comparing HaCaT cells of high- and low differentiation stages indicated that the effect of cobalt chloride on cell toxicity occurs throughout the living epidermis. CoCl2 exposure also resulted in secretion of the proinflammatory cytokines IL-1β and IL-18, and caspase-1, which indicates activation of the NLRP3 inflammasome in the cells. CoCl2 regulates the inflammasome both as primer and as an activator. Our mRNA results indicates a negative feedback mechanism in the inflamamsome due to the exposure. The inflammatory response in general is more dose than time dependent, which be important for understanding the mechanisms of allergic sensitization.
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| 6. |
- Månsson, Emeli, 1978-
(author)
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Molecular epidemiology of Staphylococcus epidermidis in prosthetic joint infections
- 2019
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Doctoral thesis (other academic/artistic)abstract
- Staphylococcus epidermidis is ubiquitous in the human microbiota, but also an important pathogen in healthcare-associated infections, such as prosthetic joint infections (PJIs). In this thesis, aspects of the molecular epidemiology of S. epidermidis in PJIs were investigated with the aim of improving our understanding of the pre- and perioperative measures required to reduce the incidence of S. epidermidis PJIs.In Paper I, S. epidermidis retrieved from air sampling in the operating field during arthroplasty was characterized by multilocus sequence typing and antibiotic susceptibility testing. No isolates belonging to sequence types (STs) 2 and 215, previously associated with PJIs, were found in the air of the operating field. During air sampling, several Staphylococcus pettenkoferi isolates were identified, and as a spin-off of Paper I, the genomic relatedness of these isolates to S. pettenkoferi isolates from blood cultures was described in Paper II.In Paper III, genetic traits distinguishing S. epidermidis isolated from PJIs were determined using genome-wide association study accounting for population effects after whole-genome sequencing (WGS) of a population- based 10-year collection of S. epidermidis isolates from PJIs and of nasal isolates retrieved from patients scheduled for arthroplasty. Genes associated with antimicrobial agents used for prophylaxis in arthroplasty, i.e., beta-lactam antibiotics, aminoglycosides, and chlorhexidine, were associated with PJI origin. S. epidermidis from PJIs were dominated by the ST2a, ST2b, ST5, and ST215 lineages.In Paper IV, selective agar plates were used to investigate colonization with methicillin resistant S. epidermidis (MRSE) in patients scheduled for arthroplasty. MRSE were further characterized by WGS. A subset of patients was found to harbour PJI-associated S. epidermidis lineages in their microbiota before hospitalization, but no isolates belonging to the ST2a lineage nor any rifampicin-resistant isolates were retrieved.
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| 7. |
- Rasmussen, Gunlög, 1973-
(author)
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Staphylococcus aureus bacteremia, molecular epidemiology and host immune response
- 2017
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Doctoral thesis (other academic/artistic)abstract
- Staphylococcus aureus is a major pathogen responsible for a considerable disease burden worldwide. It may cause a wide array of infections, from superficial skin infections to invasive bacteremia and complications such as infective endocarditis (IE) and osteomyelitis. This thesis aimed to investigate aspects of the molecular epidemiology of S. aureus and host immune response in relation to disease manifestation, severity, and over time during S. aureus bacteremia (SAB).Genotypic characteristics in isolates causing colonization, bacteremia, and bacteremia with IE were studied. The S. aureus population was genetically diverse and certain clones with their set of often lineage-specific virulence genes were associated with invasive disease. Characterization of the long-term molecular epidemiology of MSSA bacteremia showed an increased prevalence of CC5 and CC15, while CC8, CC25 and CC30 declined. Antibiotic resistance pattern was favorable and unaffected.Further, different aspects of host immune response were explored in patients with SAB during the acute phase of bacteremia. When investigating the NLRP3 inflammasome signaling, induced caspase-1 activity was found, with a great inter-individual variation between patients, and subsequent release of IL-18, indicating inflammasome activity. Finally, the dynamics of MHC class II related genes HLA-DRA and CD74 were analyzed as markers of immunosuppression. Patients with complicated SAB had significantly lower HLA-DRA expression than patients with uncomplicated bacteremia, demonstrating an association between complicated SAB and impaired immune function.In conclusion, the S. aureus genotype, as well as host factors reflected by inter-individual variations in inflammasome signaling and immune function, may all contribute to disease manifestation and outcome during SAB. An ability to measure the immune response early and continuously during the hospital stay and course of bacteremia could offer a way to tailor patient management and treatment in an individualized way.
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| 8. |
- Sahdo, Berolla, 1984-
(author)
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Inflammasomes : defense guardians in host-microbe defence
- 2013
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Doctoral thesis (other academic/artistic)abstract
- The inflammasomes are emerging as key regulators of the innate immune response as they response to cellular infection, tissue damage and/or stress. Activated inflammasomes provide a signalling platform for caspase-1 activation which subsequently processes the maturation of interleukin (IL)-1β and IL-18, and in addition promotes cell death, named pyroptosis. These effector mechanisms of the inflammasome constitute an important part of the innate immune response in host-defence.The aims of this thesis were to elucidate if the inflammasome is activated by specific pathogens, and if genetic variations lead to susceptibility to severe inflammatory diseases, such as blood stream infections. We found that the commensal pathogens Staphylococcus aureus and Propionibacterium acnes induce caspase-1 activation, the latter being a stronger activator. The data also propose that it is rather the bacterial ligands than the secreted toxins of P. acnes that induce inflammasome activation. Even though the S. aureus PVL-toxin induces a caspase-1 activation, involvement of other virulence factors are of importance. Upon S. aureus and P. acnes stimulation, inter-individual variations were found, implying that the characteristics of the host innate immune system, rather than the properties of the bacteria, are decisive for the inflammatory response. Indeed, healthy individuals with the combined polymorphisms of the NLRP3 inflammasome (C10X/Q705K) have higher levels of spontaneous IL-1β, and most intriguingly C10X polymorphism showed a strong correlation with patients with bacteremia.In conclusion, these studies suggest that different pathogens activate the inflammasomes to various degrees. The genetics of the host innate immune system, rather than the properties of the bacteria, define the inflammatory response against these bacteria, and specific genetic variations such as C10X polymorphism can increase the susceptibility for disease development.
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