| 1. |
- van Karnebeek, Clara D. M., et al.
(författare)
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CIAO1 and MMS19 de fi ciency : A lethal neurodegenerative phenotype caused by cytosolic Fe-S cluster protein assembly disorders
- 2024
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Ingår i: Genetics in Medicine. - : Elsevier. - 1098-3600 .- 1530-0366. ; 26:6
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The functionality of many cellular proteins depends on cofactors; yet, they have only been implicated in a minority of Mendelian diseases. Here, we describe the first 2 inherited disorders of the cytosolic iron-sulfur protein assembly system.Methods: Genetic testing via genome sequencing was applied to identify the underlying disease cause in 3 patients with microcephaly, congenital brain malformations, progressive developmental and neurologic impairments, recurrent infections, and a fatal outcome. Studies in patient-derived skin fibroblasts and zebrafish models were performed to investigate the biochemical and cellular consequences.Results: Metabolic analysis showed elevated uracil and thymine levels in body fluids but no pathogenic variants in DPYD, encoding dihydropyrimidine dehydrogenase. Genome sequencing identified compound heterozygosity in 2 patients for missense variants in CIAO1, encoding cytosolic iron-sulfur assembly component 1, and homozygosity for an in-frame 3-nucleotide deletion in MMS19, encoding the MMS19 homolog, cytosolic iron-sulfur assembly component, in the third patient. Profound alterations in the proteome, metabolome, and lipidome were observed in patient-derived fibroblasts. We confirmed the detrimental effect of deficiencies in CIAO1 and MMS19 in zebrafish models.Conclusion: A general failure of cytosolic and nuclear iron-sulfur protein maturation caused pleiotropic effects. The critical function of the cytosolic iron-sulfur protein assembly machinery for antiviral host defense may well explain the recurrent severe infections occurring in our patients. (c) 2024 The Authors. Published by Elsevier Inc. on behalf of American College of Medical Genetics and Genomics. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 2. |
- Palao, Teresa, et al.
(författare)
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Thrombospondin-4 mediates cardiovascular remodelling in angiotensin II-induced hypertension
- 2018
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Ingår i: Cardiovascular Pathology. - : Elsevier BV. - 1054-8807. ; 35, s. 12-19
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Tidskriftsartikel (refereegranskat)abstract
- Thrombospondin 4 (TSP-4) expression is induced in the heart and vasculature under pathological conditions, including myocardial infarction, myocardial pressure overload, and hypertension. TSP-4 is linked to remodelling processes, where it may affect extracellular matrix protein organization. In previous work, we studied the role of TSP-4 in small arteries during hypertension using Ang II-treated Thrombospondin 4 knockout (Thbs4−/−) mice. We reported increased heart weight, as well as the occurrence of aortic aneurysms in the Ang II-treated Thbs4−/− animals. In the present study, we further characterized the hearts and aortas from these animals. Hypertrophy of cardiomyocytes, together with perivascular fibrosis and inflammation was observed in the Ang II-treated Thbs4−/− hearts. In the aortas, an increase in the aortic wall cross-sectional area (CSA) and wall thickness of the Ang II-treated Thbs4−/− mice was found. More detailed investigation of the Ang II-treated Thbs4−/− aortas also revealed the appearance of aortic dissections in the outer medial layer of the arteries, as well as pronounced inflammation. No differences were found in several other extracellular matrix-related parameters, such as number of elastin breaks or stress–strain relationships. However, at the ultrastructural level, collagen fibers showed alterations in diameter in the media and adventitia of the Ang II-treated Thbs4−/− mice, in the area prone to dissection. In conclusion, we identified TSP-4 as an important protein in the development of cardiac hypertrophy and aortic dissections in Ang II-induced hypertension.
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| 3. |
- Wenzel, Michaela, 1986, et al.
(författare)
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Control of septum thickness by the curvature of SepF polymers
- 2021
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 118:2
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Tidskriftsartikel (refereegranskat)abstract
- Gram-positive bacteria divide by forming a thick cross wall. How the thickness of this septal wall is controlled is unknown. In this type of bacteria, the key cell division protein FtsZ is anchored to the cell membrane by two proteins, FtsA and/or SepF. We have isolated SepF homologs from different bacterial species and found that they all polymerize into large protein rings with diameters varying from 19 to 44 nm. Interestingly, these values correlated well with the thickness of their septa. To test whether ring diameter determines septal thickness, we tried to construct different SepF chimeras with the purpose to manipulate the diameter of the SepF protein ring. This was indeed possible and confirmed that the conserved core domain of SepF regulates ring diameter. Importantly, when SepF chimeras with different diameters were expressed in the bacterial host Bacillus subtilis, the thickness of its septa changed accordingly. These results strongly support a model in which septal thickness is controlled by curved molecular clamps formed by SepF polymers attached to the leading edge of nascent septa. This also implies that the intrinsic shape of a protein polymer can function as a mold to shape the cell wall.
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| 4. |
- Daleke-Schermerhorn, Maria H., et al.
(författare)
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Decoration of Outer Membrane Vesicles with Multiple Antigens by Using an Autotransporter Approach
- 2014
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 80:18, s. 5854-5865
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Tidskriftsartikel (refereegranskat)abstract
- Outer membrane vesicles (OMVs) are spherical nanoparticles that naturally shed from Gram-negative bacteria. They are rich in immunostimulatory proteins and lipopolysaccharide but do not replicate, which increases their safety profile and renders them attractive vaccine vectors. By packaging foreign polypeptides in OMVs, specific immune responses can be raised toward heterologous antigens in the context of an intrinsic adjuvant. Antigens exposed at the vesicle surface have been suggested to elicit protection superior to that from antigens concealed inside OMVs, but hitherto robust methods for targeting heterologous proteins to the OMV surface have been lacking. We have exploited our previously developed hemoglobin protease (Hbp) autotransporter platform for display of heterologous polypeptides at the OMV surface. One, two, or three of the Mycobacterium tuberculosis antigens ESAT6, Ag85B, and Rv2660c were targeted to the surface of Escherichia coli OMVs upon fusion to Hbp. Furthermore, a hypervesiculating Delta tolR Delta tolA derivative of attenuated Salmonella enterica serovar Typhimurium SL3261 was generated, enabling efficient release and purification of OMVs decorated with multiple heterologous antigens, exemplified by the M. tuberculosis antigens and epitopes from Chlamydia trachomatis major outer membrane protein (MOMP). Also, we showed that delivery of Salmonella OMVs displaying Ag85B to antigen-presenting cells in vitro results in processing and presentation of an epitope that is functionally recognized by Ag85B-specific T cell hybridomas. In conclusion, the Hbp platform mediates efficient display of (multiple) heterologous antigens, individually or combined within one molecule, at the surface of OMVs. Detection of antigen-specific immune responses upon vesicle-mediated delivery demonstrated the potential of our system for vaccine development.
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| 5. |
- Jong, Wouter S. P., et al.
(författare)
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An autotransporter display platform for the development of multivalent recombinant bacterial vector vaccines
- 2014
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Ingår i: Microbial Cell Factories. - : Springer Science and Business Media LLC. - 1475-2859. ; 13, s. -162
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Tidskriftsartikel (refereegranskat)abstract
- Background: The Autotransporter pathway, ubiquitous in Gram-negative bacteria, allows the efficient secretion of large passenger proteins via a relatively simple mechanism. Capitalizing on its crystal structure, we have engineered the Escherichia coli autotransporter Hemoglobin protease (Hbp) into a versatile platform for secretion and surface display of multiple heterologous proteins in one carrier molecule. Results: As proof-of-concept, we demonstrate efficient secretion and high-density display of the sizeable Mycobacterium tuberculosis antigens ESAT6, Ag85B and Rv2660c in E. coli simultaneously. Furthermore, we show stable multivalent display of these antigens in an attenuated Salmonella Typhimurium strain upon chromosomal integration. To emphasize the versatility of the Hbp platform, we also demonstrate efficient expression of multiple sizeable antigenic fragments from Chlamydia trachomatis and the influenza A virus at the Salmonella cell surface. Conclusions: The successful efficient cell surface display of multiple antigens from various pathogenic organisms highlights the potential of Hbp as a universal platform for the development of multivalent recombinant bacterial vector vaccines.
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| 6. |
- Jong, Wouter SP, et al.
(författare)
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A structurally informed autotransporter platform for efficient heterologous protein secretion and display
- 2012
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Ingår i: Microbial Cell Factories. - : Springer Science and Business Media LLC. - 1475-2859. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The self-sufficient autotransporter (AT) pathway, ubiquitous in Gram-negative bacteria, combines a relatively simple protein secretion mechanism with a high transport capacity. ATs consist of a secreted passenger domain and a β-domain that facilitates transfer of the passenger across the cell-envelope. They have a great potential for the extracellular expression of recombinant proteins but their exploitation has suffered from the limited structural knowledge of carrier ATs. Capitalizing on its crystal structure, we have engineered the Escherichia coli AT Hemoglobin protease (Hbp) into a platform for the secretion and surface display of heterologous proteins, using the Mycobacterium tuberculosis vaccine target ESAT6 as a model protein.RESULTS: Based on the Hbp crystal structure, five passenger side domains were selected and one by one replaced by ESAT6, whereas a β-helical core structure (β-stem) was left intact. The resulting Hbp-ESAT6 chimeras were efficiently and stably secreted into the culture medium of E. coli. On the other hand, Hbp-ESAT6 fusions containing a truncated β-stem appeared unstable after translocation, demonstrating the importance of an intact β-stem. By interrupting the cleavage site between passenger and β-domain, Hbp-ESAT6 display variants were constructed that remain cell associated and facilitate efficient surface exposure of ESAT6 as judged by proteinase K accessibility and whole cell immuno-EM analysis. Upon replacement of the passenger side domain of an alternative AT, EspC, ESAT6 was also efficiently secreted, showing the approach is more generally applicable to ATs. Furthermore, Hbp-ESAT6 was efficiently displayed in an attenuated Salmonella typhimurium strain upon chromosomal integration of a single encoding gene copy, demonstrating the potential of the Hbp platform for live vaccine development.CONCLUSIONS: We developed the first structurally informed AT platform for efficient secretion and surface display of heterologous proteins. The platform has potential with regard to the development of recombinant live vaccines and may be useful for other biotechnological applications that require high-level secretion or display of recombinant proteins by bacteria.
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| 7. |
- Kluza, Ewelina, et al.
(författare)
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Diverse ultrastructural landscape of atherosclerotic endothelium
- 2021
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Ingår i: Atherosclerosis. - : Elsevier BV. - 0021-9150. ; 339, s. 35-45
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: The endothelium plays a major role in atherosclerosis, yet the endothelial plaque surface is a largely uncharted territory. Here we hypothesize that atherosclerosis-driven remodeling of the endothelium is a dynamic process, involving both damaging and regenerative mechanisms. Methods: Using scanning electron microscopy (SEM) and immuno-SEM, we studied endothelial junction ultrastructure, endothelial openings and immune cell-endothelium interactions in eight apoe−/− mice and two human carotid plaques. Results: The surface of early mouse plaques (n = 11) displayed a broad range of morphological alterations, including junctional disruptions and large transcellular endothelial pores with the average diameter between 0.6 and 3 μm. The shoulder region of advanced atherosclerotic lesions (n = 7) had a more aggravated morphology with 8 μm-size paracellular openings at two-fold higher density. In contrast, the central apical surface of advanced plaques, i.e., the plaque body (n = 7), displayed endothelial normalization, as shown by a significantly higher frequency of intact endothelial junctions and a lower incidence of paracellular pores. This normalized endothelial phenotype correlated with low immune cell density (only 5 cells/mm2). The human carotid plaque surface (n = 2) displayed both well-organized and disrupted endothelium with similar features as described above. In addition, they were accompanied by extensive thrombotic areas. Conclusions: Our study unveils the spectrum of endothelial abnormalities associated with the development of atherosclerosis. These were highly abundant in early lesions and in the shoulder region of advanced plaques, while normalized at the advanced plaque's body. Similar endothelial features were observed in human atherosclerotic plaques, underlining the versatility of endothelial transformations in atherosclerosis.
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| 8. |
- Sun, Jiangming, et al.
(författare)
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Spatial Transcriptional Mapping Reveals Site-Specific Pathways Underlying Human Atherosclerotic Plaque Rupture
- 2023
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Ingår i: Journal of the American College of Cardiology. - 0735-1097. ; 81:23, s. 2213-2227
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Tidskriftsartikel (refereegranskat)abstract
- Background: Atherosclerotic plaque ruptures, triggered by blood flow–associated biomechanical forces, cause most myocardial infarctions and strokes. Objectives: This study aims to investigate the exact location and underlying mechanisms of atherosclerotic plaque ruptures, identifying therapeutic targets against cardiovascular events. Methods: Histology, electron microscopy, bulk and spatial RNA sequencing on human carotid plaques were studied in proximal, most stenotic, and distal regions along the longitudinal blood flow direction. Genome-wide association studies were used to examine heritability enrichment and causal relationships of atherosclerosis and stroke. Associations between top differentially expressed genes (DEGs) and preoperative and postoperative cardiovascular events were examined in a validation cohort. Results: In human carotid atherosclerotic plaques, ruptures predominantly occurred in the proximal and most stenotic regions but not in the distal region. Histologic and electron microscopic examination showed that proximal and most stenotic regions exhibited features of plaque vulnerability and thrombosis. RNA sequencing identified DEGs distinguishing the proximal and most stenotic regions from the distal region which were deemed as most relevant to atherosclerosis-associated diseases as shown by heritability enrichment analyses. The identified pathways associated with the proximal rupture-prone regions were validated by spatial transcriptomics, firstly in human atherosclerosis. Of the 3 top DEGs, matrix metallopeptidase 9 emerged particularly because Mendelian randomization suggested that its high circulating levels were causally associated with atherosclerosis risk. Conclusions: Our findings show plaque site–specific transcriptional signatures associated with proximal rupture-prone regions of carotid atherosclerotic plaques. This led to the geographical mapping of novel therapeutic targets, such as matrix metallopeptidase 9, against plaque rupture.
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