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- Bauer, Susanne
(författare)
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Cell type-specific translatome analysis of mouse models of three genetic neurodegenerative diseases
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The burden neurodegenerative diseases place on patients, their loved ones, and the healthcare system is significant, and despite extensive research efforts, there is currently no cure. Since degenerative changes in the brain can begin years before symptoms appear, early intervention is critical. Additionally, neurodegenerative diseases target certain brain regions and neuron types early on. A more comprehensive understanding of the affected cells during the presymptomatic phase is therefore crucial for an effective and targeted intervention. Herein, we isolated, sequenced, and analyzed translatome samples from six neuronal cell types in knock-in mouse models of three monogenic neurodegenerative diseases at a presymptomatic stage: genetic Creutzfeldt-Jakob disease (gCJD), fatal familial insomnia (FFI), and Huntington’s disease (HD). To obtain the translatome samples, we used RiboTag to immunoprecipitate HA-tagged ribosomes with their translating mRNAs from targeted cell types. We analyzed six cell types across two brain regions: cerebral and cerebellar glutamatergic and GABAergic neurons, and cerebral parvalbumin (PV) and somatostatin (SST)-expressing neurons. In the first paper, we focused our analysis on the prion diseases, gCJD (E200K) and FFI (D178N). Here observed a similar response of SST+ neurons, a cell type not previously reported as affected, in both disease models. This was characterized by upregulation of ribosomeassociated genes, and downregulation of cytoskeleton and synapse-associated genes in FFI. Weighted gene co-expression network analysis of SST+ neurons pointed towards the downregulation of mTOR inhibition as a potential mechanism underlying the observed gene expression changes. In the second paper, we analyzed a 129S4-HdhQ200 knock-in mouse model of HD. Histological and behavioral assessment revealed pathological changes in the striatum and cerebellum at 9 months and a later, mild behavioral phenotype. Translatome analysis indicated a surprisingly strong response in reportedly resistant glutamatergic neurons of the cerebellum, marked by upregulation of cell cycle regulators Ccnd1 and chromobox protein genes. In the third paper, we aimed to compare disease-specific responses of PV+ neurons across the three disease models. This analysis revealed a milder response in HD compared to prion disease at comparable disease stages. Functional analysis further indicated PV+ neurons may respond differently in the investigated diseases, showing upregulation of immune response-associated pathways in gCJD, neurodegenerative-disease pathways in FFI, and autophagy in HD. Lastly, the generation of mouse models such as were used in papers I-III requires stable and predictable transgene expression without interfering with the expression of endogenous genes. In the fourth paper, we conducted a pilot study to compare three potential loci, Rpl6, Rpl7, and Eef1a1, as potential safe harbors for transgene integration. Preliminary results indicated that the Rpl6 locus may be best suited for our purposes. Furthermore, this work generated a novel dataset consisting of translatome profiles of six cell types in three neurodegenerative disease models. This provides gene expression data at a previously unavailable level of cellular resolution, especially in prion disease. We believe that this data will serve as a valuable resource for future research and help expand our understanding of the early molecular mechanisms in neurodegenerative disease beyond the scope of this thesis.
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| 2. |
- Stensson, Niclas, 1974-
(författare)
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Endocannabinoids and Related Lipids in Chronic Pain : Analytical and Clinical Aspects
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In Europe, approximately one in five adults experience chronic pain, pain that lasts more than three months. Chronic pain is a significant problem not only for those people suffering from chronic pain but also for society. The prevalence of chronic pain is higher in women and lower socioeconomic groups. Although chronic pain often originates in a specific site, it may eventually spread to several sites, transforming into chronic widespread pain (CWP), a condition evident in about 10% of the adult population. Approximately 1.2-5.4% are classified with fibromyalgia (FM). In addition to CWP, common symptoms of FM include, stiffness, fatigue, sleep disturbances, and cognitive dysfunction and common co-morbidities include depression and anxiety. Although FM/CWP has been reported to alter both central and peripheral nociceptive mechanisms, no objective biomarkers have been found that correlate with CWP/FM and no standard examinations such as blood test, X-ray or computed tomography can provide support for a diagnosis. Because there are no objective biomarkers that correlate with the pathophysiological processes associated with CWP/FM, this debilitating disease is difficult to diagnose and ultimately treat. However, there are some promising therapeutic targets for chronic pain with inter alia analgesic, anti-inflammatory, and stress modulating properties: the endocannabinoids (ECs) arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG) and their related lipids oleoylethanolamide (OEA), palmitoylethanolamide (PEA), and stearoylethanolamide (SEA).This thesis investigates whether ECs and the related N-acylethanolamines (NAEs) can be used as potential biomarkers for CWP/FM. Specifically, the studies compared the peripheral and systemic levels of ECs and NAEs in 121 women with CWP/FM and in 137 healthy controls in two different cohorts. In addition, the correlation between lipid levels and common pain characteristics such as intensity, sensitivity, and duration were investigated. The EC and related lipid levels were measured using liquid chromatography in combination with tandem mass spectrometry. Multivariate data analysis was used for biomarker evaluation.Compared to the healthy controls, the CWP/FM patients had significantly higher concentrations of OEA, PEA, and SEA in muscle and plasma (p ≤ 0.05) and significantly higher 2-AG in plasma (p ≤ 0.01). These results may indicate that NAEs, are mobilized differently in painful muscles compared with pain free muscles. Moreover, increased systemic levels of NAEs and 2-AG in patients might be signs of ongoing low-grade inflammation inCWP/FM. These findings contribute to a better understanding of how peripheral and systemic factors maintain and activate chronic pain. Although the investigated lipids have statistically significant effects but biologically uncertain role in the clinical manifestations of CWP/FM. Thus plasma lipids are not a good biomarker for CWP/FM. Nevertheless, increased lipid levels indicate a metabolic asymmetry in CWP/FM, a finding that could serve as a basis for more research on pain management.
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| 3. |
- Roos Ljungberg, Karin, 1988-
(författare)
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Secretory Autoantibodies in Rheumatoid Arthritis
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease in which autoantibodies, such as anti-citrullinated protein antibodies (ACPA), can be detected in the serum of patients. Autoantibodies may appear in the circulation years before clinical signs of joint inflammation occur, indicating that early immunological pathogenetic steps take place outside of the joints. Although many of these mechanisms are currently unknown, the initial events leading up to ACPA production are thought to occur at mucosal surfaces. In this thesis, mucosa-associated secretory ACPA are investigated in the circulation and in local mucosal secretions to: (i) improve the understanding of the mucosal connection in RA; and (ii) investigate whether these antibodies can improve diagnostics and prognostics in early RA. We identified circulating secretory component containing (SC) ACPA in a subpopulation of patients (both early and established RA) and at-risk patients, with a prevalence of 16%-21%. In addition, SC ACPA was detected in bronchoalveolar lavage fluid (BALF) and IgA ACPA in saliva, indicating local production in the lungs and in the oral cavity. In at-risk patients who were positive for IgG ACPA, we found that the levels of circulating SC ACPA at inclusion predicted arthritis development. Circulating SC ACPA was associated with higher disease activity, including increased levels of inflammatory markers, in patients with early RA. Levels of circulating SC ACPA were associated with high-resolution computed tomography (HRCT) findings (parenchymal lung abnormalities and bronchiectasis) and smoking, but not with risk genes (shared epitope). We confirmed the presence of salivary ACPA and identified a novel association with increased disease activity and functional disability. In summary, SC ACPA is present in the sera of patients with RA who manifest different phases of the disease, and we found associations with arthritis onset, smoking, systemic inflammation, and lung abnormalities. SC ACPA is also detectable in mucosal secretions from the lungs and the oral cavity. These findings suggest that mucosal ACPA production may be an important factor in RA development and progression, and that serum SC ACPA should be further evaluated as a prognostic marker for disease onset among at-risk individuals.
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