| 1. |
- Nordeman, Patrik, et al.
(författare)
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C-11 and F-18 Radiolabeling of Tetra- and Pentathiophenes as PET-Ligands for Amyloid Protein Aggregates
- 2016
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Ingår i: ACS Medicinal Chemistry Letters. - : American Chemical Society (ACS). - 1948-5875 .- 1948-5875. ; 7:4, s. 368-373
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Tidskriftsartikel (refereegranskat)abstract
- Three oligothiophenes were evaluated as PET ligands for the study of local and systemic amyloidosis ex vivo using tissue from patients with amyloid deposits and in vivo using healthy animals and PET-CT. The ex vivo binding studies revealed that all three labeled compounds bound specifically to human amyloid deposits. Specific binding was found in the heart, kidney, liver, and spleen. To verify the specificity of the oligothiophenes toward amyloid deposits, tissue sections with amyloid pathology were stained using the fluorescence exhibited by the compounds and evaluated with multiphoton microscopy. Furthermore, a in vivo monkey PET-CT study showed very low uptake in the brain, pancreas, and heart of the healthy animal indicating low nonspecific binding to healthy tissue. The biological evaluations indicated that this is a promising group of compounds for the visualization of systemic and localized amyloidosis.
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| 2. |
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| 3. |
- Sjölander, Daniel, et al.
(författare)
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Establishing the fluorescent amyloid ligand h-FTAA for studying human tissues with systemic and localized amyloid
- 2016
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Ingår i: Amyloid. - : Informa UK Limited. - 1350-6129 .- 1744-2818. ; 23:2, s. 98-108
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Tidskriftsartikel (refereegranskat)abstract
- Rapid and accurate detection of amyloid deposits in routine surgical pathology settings are of great importance. The use of fluorescence microscopy in combination with appropriate amyloid specific dyes is very promising in this regard. Here we report that a luminescent conjugated oligothiophene, h-FTAA, rapidly and with high sensitivity and selectivity detects amyloid deposits in verified clinical samples from systemic amyloidosis patients with AA, AL and ATTR types; as well as in tissues laden with localized amyloidosis of AANF, AIAPP and ASem1 type. The probe h-FTAA emitted yellow red fluorescence on binding to amyloid deposits, whereas no apparent staining was observed in surrounding tissue. The only functional structure stained with h-FTAA showing the amyloidotypic fluorescence spectrum was Paneth cell granules in intestine. Screening of 114 amyloid containing tissues derived from 107 verified (Congo red birefringence and/or immunohistochemistry) amyloidosis patients revealed complete correlation between h-FTAA and Congo red fluorescence (107/107, 100% sensitivity). The majority of Congo red negative control cases (27 of 32, 85% specificity) were negative with h-FTAA. Small Congo red negative aggregates in kidney, liver, pancreas and duodenum were found by h-FTAA fluorescence in five control patients aged 72-83 years suffering from diverse diseases. The clinical significance of these false-positive lesions is currently not known. Because h-FTAA fluorescence is one magnitude brighter than Congo red and as the staining is performed four magnitudes lower than the concentration of dye, we believe that these inclusions are beyond detection by Congo red. We conclude that h-FTAA is a fluorescent hypersensitive, rapid and powerful tool for identifying amyloid deposits in tissue sections. Use of h-FTAA can be exploited as a rapid complementary technique for accurate detection of amyloid in routine surgical pathology settings. Our results also implicate the potential of the technique for detection of prodromal amyloidosis as well as for discovery of new amyloid-like protein aggregates in humans.
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| 4. |
- Aguilar-Calvo, Patricia, et al.
(författare)
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Generation of novel neuroinvasive prions following intravenous challenge
- 2018
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Ingår i: Brain Pathology. - : WILEY. - 1015-6305 .- 1750-3639. ; 28:6, s. 999-1011
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Tidskriftsartikel (refereegranskat)abstract
- Prions typically spread into the central nervous system (CNS), likely via peripheral nerves. Yet prion conformers differ in their capacity to penetrate the CNS; certain fibrillar prions replicate persistently in lymphoid tissues with no CNS entry, leading to chronic silent carriers. Subclinical carriers of variant Creutzfeldt-Jakob (vCJD) prions in the United Kingdom have been estimated at 1:2000, and vCJD prions have been transmitted through blood transfusion, however, the circulating prion conformers that neuroinvade remain unclear. Here we investigate how prion conformation impacts brain entry of transfused prions by challenging mice intravenously to subfibrillar and fibrillar strains. We show that most strains infiltrated the brain and caused terminal disease, however, the fibrillar prions showed reduced CNS entry in a strain-dependent manner. Strikingly, the highly fibrillar mCWD prion strain replicated in the spleen and emerged in the brain as a novel strain, indicating that a new neuroinvasive prion had been generated from a previously non-neuroinvasive strain. The new strain showed altered plaque morphology, brain regions targeted and biochemical properties and these properties were maintained upon intracerebral passage. Intracerebral passage of prion-infected spleen re-created the new strain. Splenic prions resembled the new strain biochemically and intracerebral passage of prion-infected spleen re-created the new strain, collectively suggesting splenic prion replication as a potential source. Taken together, these results indicate that intravenous exposure to prion-contaminated blood or blood products may generate novel neuroinvasive prion conformers and disease phenotypes, potentially arising from prion replication in non-neural tissues or from conformer selection.
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| 5. |
- Babu Moparthi, Satish, et al.
(författare)
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Differential conformational modulations of MreB folding upon interactions with GroEL/ES and TRiC chaperonin components
- 2016
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 6:28386
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Tidskriftsartikel (refereegranskat)abstract
- Here, we study and compare the mechanisms of action of the GroEL/GroES and the TRiC chaperonin systems on MreB client protein variants extracted from E. coli. MreB is a homologue to actin in prokaryotes. Single-molecule fluorescence correlation spectroscopy (FCS) and time-resolved fluorescence polarization anisotropy report the binding interaction of folding MreB with GroEL, GroES and TRiC. Fluorescence resonance energy transfer (FRET) measurements on MreB variants quantified molecular distance changes occurring during conformational rearrangements within folding MreB bound to chaperonins. We observed that the MreB structure is rearranged by a binding-induced expansion mechanism in TRiC, GroEL and GroES. These results are quantitatively comparable to the structural rearrangements found during the interaction of beta-actin with GroEL and TRiC, indicating that the mechanism of chaperonins is conserved during evolution. The chaperonin-bound MreB is also significantly compacted after addition of AMP-PNP for both the GroEL/ES and TRiC systems. Most importantly, our results showed that GroES may act as an unfoldase by inducing a dramatic initial expansion of MreB (even more than for GroEL) implicating a role for MreB folding, allowing us to suggest a delivery mechanism for GroES to GroEL in prokaryotes.
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| 6. |
- Bednarska, Natalia G., et al.
(författare)
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Protein aggregation as an antibiotic design strategy
- 2016
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Ingår i: Molecular Microbiology. - : WILEY-BLACKWELL. - 0950-382X .- 1365-2958. ; 99:5, s. 849-865
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Tidskriftsartikel (refereegranskat)abstract
- Taking advantage of the xenobiotic nature of bacterial infections, we tested whether the cytotoxicity of protein aggregation can be targeted to bacterial pathogens without affecting their mammalian hosts. In particular, we examined if peptides encoding aggregation-prone sequence segments of bacterial proteins can display antimicrobial activity by initiating toxic protein aggregation in bacteria, but not in mammalian cells. Unbiased in vitro screening of aggregating peptide sequences from bacterial genomes lead to the identification of several peptides that are strongly bactericidal against methicillin-resistant Staphylococcus aureus. Upon parenteral administration in vivo, the peptides cured mice from bacterial sepsis without apparent toxic side effects as judged from histological and hematological evaluation. We found that the peptides enter and accumulate in the bacterial cytosol where they cause aggregation of bacterial polypeptides. Although the precise chain of events that leads to cell death remains to be elucidated, the ability to tap into aggregation-prone sequences of bacterial proteomes to elicit antimicrobial activity represents a rich and unexplored chemical space to be mined in search of novel therapeutic strategies to fight infectious diseases.
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| 7. |
- Björkman, Andrea, et al.
(författare)
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Aberrant recombination and repair during immunoglobulin class switching in BRCA1-deficient human B cells.
- 2015
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Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 112:7, s. 2157-2162
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Tidskriftsartikel (refereegranskat)abstract
- Breast cancer type 1 susceptibility protein (BRCA1) has a multitude of functions that contribute to genome integrity and tumor suppression. Its participation in the repair of DNA double-strand breaks (DSBs) during homologous recombination (HR) is well recognized, whereas its involvement in the second major DSB repair pathway, nonhomologous end-joining (NHEJ), remains controversial. Here we have studied the role of BRCA1 in the repair of DSBs in switch (S) regions during immunoglobulin class switch recombination, a physiological, deletion/recombination process that relies on the classical NHEJ machinery. A shift to the use of microhomology-based, alternative end-joining (A-EJ) and increased frequencies of intra-S region deletions as well as insertions of inverted S sequences were observed at the recombination junctions amplified from BRCA1-deficient human B cells. Furthermore, increased use of long microhomologies was found at recombination junctions derived from E3 ubiquitin-protein ligase RNF168-deficient, Fanconi anemia group J protein (FACJ, BRIP1)-deficient, or DNA endonuclease RBBP8 (CtIP)-compromised cells, whereas an increased frequency of S-region inversions was observed in breast cancer type 2 susceptibility protein (BRCA2)-deficient cells. Thus, BRCA1, together with its interaction partners, seems to play an important role in repairing DSBs generated during class switch recombination by promoting the classical NHEJ pathway. This may not only provide a general mechanism underlying BRCA1's function in maintaining genome stability and tumor suppression but may also point to a previously unrecognized role of BRCA1 in B-cell lymphomagenesis.
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| 8. |
- Brydsten, Anna, et al.
(författare)
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Does contextual unemployment matter for health status across the life course?
- 2016
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Ingår i: European Journal of Public Health. - : Oxford University Press. - 1101-1262 .- 1464-360X. ; 26:Suppl 1, s. 142-142
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Tidskriftsartikel (refereegranskat)abstract
- Background: Individual health is affected by one’s individual life conditionsand by the context in which individuals live, interact anddevelop. Research shows that living in a neighbourhood withhigh levels of unemployment might affect residents’ health, atleast partially independent of own labour market status.However, how such contextual-individual transactions playout across the life course is unknown. The present study aims:(i) to examine whether neighbourhood unemployment isrelated to health status across the life course independently ofthe individual employment from adolescence to middle age(age 16 to 42); and (ii) to analyse whether this relationship isobservable at four specific life course periods from adolescenceto middle age (age 16, 21, 30 and 42).Methods: A 26-year prospective Swedish cohort (n = 1010), linked toregister data on neighbourhood unemployment. Individualemployment and functional somatic symptoms were measuredby self-reported questionnaire data. Two models of hierarchallinear regressions were built: a longitudinal analysis, and a setof age-specific cross-sectional analyses at each age.Results: The longitudinal analysis showed an independent contributionof neighbourhood unemployment and individual employmenton FSS across the life course. The cross-sectional analysisshowed an association at age 30, when accounting forindividual employment, but no association was found at age21 and 42.Conclusions: Neighbourhood unemployment has a significant relationshipwith functional somatic symptoms across the life course. Thereseems to be an age-specific pattern where neighbourhoodunemployment may have stronger implications in earlyadulthood than in other phases of the life courseKey messages:High neighbourhood unemployment predicts higher levelsof individual FSS across the life course, independently ofown labour market position, socioeconomic status andeducationThese findings stress the importance of neighbourhoodunemployment for current health status as well as development of health status across the life course, particular duringearly adulthood
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| 9. |
- Brydsten, Anna, et al.
(författare)
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Does contextual unemployment matter for health status across the life course? A longitudinal multilevel study exploring the link between neighbourhood unemployment and functional somatic symptoms
- 2017
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Ingår i: Health and Place. - : Elsevier BV. - 1353-8292 .- 1873-2054. ; 43, s. 113-120
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Tidskriftsartikel (refereegranskat)abstract
- This study examines whether neighbourhood unemployment is related to functional somatic symptoms, independently of the individual employment, across the life course and at four specific life course periods (age 16, 21, 30 and 42). Self-reported questioner data was used from a 26-year prospective Swedish cohort (n=1010) with complementary neighbourhood register data. A longitudinal and a set of age-specific cross-sectional hierarchal linear regressions was carried out. The results suggest that living in a neighbourhood with high unemployment has implications for residents' level of functional somatic symptoms, regardless of their own unemployment across time, particularly at age 30.
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| 10. |
- Brydsten, Anna, 1984-
(författare)
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Yesterday once more? Unemployment and health inequalities across the life course in northern Sweden
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- AbstractBackground. It is relatively well established in previous research that unemployment has direct health consequences in terms of mental and physical ill health. Recently, knowledge has emerged indicating that unemployment can lead to economic consequences that remain long after re-establishment in the labour market. However, few empirical studies have been able to apply a life course perspective asking whether there are also long-term health consequences of unemployment, and, when and in which context unemployment may affect the individual health status across the life course. The aim of this thesis was to analyse the relationship between unemployment and illness across the life course, and how it relates to individual and structural factors in the geographical setting of northern Sweden. In particular, three main areas have been explored: youth unemployment and illness in adulthood (Paper I and Paper II), contextual unemployment of national unemployment rate and neighbourhood unemployment (Paper II and Paper III) and lastly, social determinants of health inequality between employment statuses (Paper IV).Methods. This thesis is positioned in Sweden between the early 1980s and the mid-2010s, following two comparable cohorts sampled from northern Sweden (26 and 19 years follow-up time respectively from youth to midlife) and a cross-sectional sample from 2014 of the four northernmost counties in Sweden. The two longitudinal cohorts comprised the Northern Swedish Cohort and the Younger Northern Swedish Cohort, consisting of all pupils in the 9th grade of compulsory school in Luleå municipality in 1981 and 1989. The participants responded to an extensive questionnaire on socioeconomic factors, work and health, in 5 and 2 waves respectively of data collections. Neighbourhood register data from Statistics Sweden was also collected for all participants in the Northern Sweden Cohort. At the latest data collection, 94.3% (n=1010) participated in the Northern Sweden Cohort and 85.6% (n=686) in the Younger Northern Sweden Cohort. The cross-sectional study Health on Equal Terms is a national study, administered by the Public Health Agency together with Statistics Sweden and county councils with the aim of mapping public health and living conditions in the country over time. In this thesis, material from 2014 has been used for northern Sweden with a response rate of around 50% (effective sample n=12769). The statistical analyses used were linear regression, multilevel analysis and difference-in-difference analysis to estimate the concurrent and long-term health consequences of unemployment, and a decomposition analysis to disentangle the inequality in health between different labour market positions. The health outcomes in focus were functional somatic symptoms (the occurrence of relatively common physical illnesses such as head, muscle and stomach ache, insomnia and palpitation) and psychological distress.Results. Among men only, as little as one month of youth unemployment was related to increased levels of functional somatic symptoms in midlife, regardless of previous ill health or unemployment later in life, although only during relatively low national unemployment (pre-recession) when comparing with youth unemployment during high national unemployment (recession). This was explained by the health promoting effect of more time spent in higher education during the recession period. Furthermore, the health impact of neighbourhood unemployment highlights the importance of the contextual setting for individuals’ health both across the life course and at specific periods of life. Lastly, employment-related mental health inequalities exist for both men and women in all life phases (youth, adulthood and midlife). Economic and social deprivation related to unemployment and illness varied across different phases in life and across genders.Conclusion. The key findings of this thesis paint a rather pessimistic vision of the future: one’s own and others’ unemployment may cause not only ill health today but also ill health later in life. Importantly, the responsibility of unemployment and the associated ill health should not be placed on the already marginalised individuals and communities. Instead, the responsibility should be directed towards the structural aspects of society and the political choices that shape these. In other words, health inequality manifested by the position in the labour market is socially produced, unfair and changeable through political decisions. The results of this study therefore cannot contribute to any simple or concrete solutions to the concurrent or long-term health consequences of individual or contextual unemployment, as the solution is beyond the areas of responsibility and abilities of research. However, if there are long-term health consequences of one’s own and other people’s unemployment, labour market and public health policies should be initiated from a young age and continue throughout the life course to reduce individual suffering and future costs of social insurance, sick-leave and unemployment benefits.
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