| 1. |
- Mossmann, Dirk, et al.
(author)
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Amyloid-beta Peptide Induces Mitochondrial Dysfunction by Inhibition of Preprotein Maturation
- 2014
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In: Cell Metabolism. - : Elsevier BV. - 1550-4131 .- 1932-7420. ; 20:4, s. 662-669
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Journal article (peer-reviewed)abstract
- Most mitochondrial proteins possess N-terminal presequences that are required for targeting and import into the organelle. Upon import, presequences are cleaved off by matrix processing peptidases and subsequently degraded by the peptidasome Cym1/PreP, which also degrades Amyloid-beta peptides (A beta). Here we find that impaired turnover of presequence peptides results in feedback inhibition of presequence processing enzymes. Moreover, A beta inhibits degradation of presequence peptides by PreP, resulting in accumulation of mitochondrial preproteins and processing intermediates. Dysfunctional preprotein maturation leads to rapid protein degradation and an imbalanced organellar proteome. Our findings reveal a general mechanism by which A beta peptide can induce the multiple diverse mitochondrial dysfunctions accompanying Alzheimer's disease.
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| 2. |
- Ring, Julia, et al.
(author)
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Mitochondrial energy metabolism is required for lifespan extension by the spastic paraplegia-associated protein spartin
- 2017
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In: Microbial Cell. - : Shared Science Publishers OG. - 2311-2638. ; 4:12, s. 411-422
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Journal article (peer-reviewed)abstract
- Hereditary spastic paraplegias, a group of neurodegenerative disorders, can be caused by loss-of-function mutations in the protein spartin. However, the physiological role of spartin remains largely elusive. Here we show that heterologous expression of human or Drosophila spartin extends chronological lifespan of yeast, reducing age-associated ROS production, apoptosis, and necrosis. We demonstrate that spartin localizes to the proximity of mitochondria and physically interacts with proteins related to mitochondrial and respiratory metabolism. Interestingly, Nde1, the mitochondrial external NADH dehydrogenase, and Pda1, the core enzyme of the pyruvate dehydrogenase complex, are required for spartin-mediated cytoprotection. Furthermore, spartin interacts with the glycolysis enhancer phospo-fructokinase-2,6 (Pfk26) and is sufficient to complement for PFK26-deficiency at least in early aging. We conclude that mitochondria-related energy metabolism is crucial for spartin's vital function during aging and uncover a network of specific interactors required for this function.
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| 3. |
- Frygner-Holm, Sara, et al.
(author)
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Pretend Play as an Intervention for Children With Cancer : A Feasibility Study
- 2020
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In: Journal of Pediatric Oncology Nursing. - : Sage Publications. - 1043-4542 .- 1532-8457. ; 37:1, s. 65-75
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Journal article (peer-reviewed)abstract
- Children with cancer suffer from symptoms and burdensome treatments that often cause distress to children and their families. Mortality is one aspect of cancer diagnosis, while another is the quality of life and well-being during and after the treatment. By supporting children's communication, self-efficacy and coping ability in the care situation, children are given the possibilities for increased independence and participation and are allowed to develop an influence over their care. The aim of this study was to develop and evaluate the feasibility and acceptability of an adult-facilitated pretend play intervention for children with cancer. Five children with ongoing treatment for cancer were invited to a play intervention that consisted of six to eight sessions of structured pretend play aimed at increasing participation, independence, and well-being. A mixed method design was used to evaluate the feasibility and acceptability of the play intervention. Measures were collected before and after interventions, and in conjunction with every play session. Results suggest that the children enjoyed the play intervention. Findings indicate small improvements regarding self-efficacy in care situations and equal or increased quality of life for participants. A main finding was that no adverse events or increased worrying was reported in conjunction with play sessions. Therefore, the intervention is regarded as safe, feasible, and acceptable as reported by participants and their primary caregivers and a possible means of increasing participation and independence in children with a cancer diagnosis.
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| 4. |
- Perez-Shibayama, Christian, et al.
(author)
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Type I interferon signaling in fibroblastic reticular cells prevents exhaustive activation of antiviral CD8+ T cells.
- 2020
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In: Science immunology. - 2470-9468. ; 5:51
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Journal article (peer-reviewed)abstract
- Fibroblastic reticular cells (FRCs) are stromal cells that actively promote the induction of immune responses by coordinating the interaction of innate and adaptive immune cells. However, whether and to which extent immune cell activation is determined by lymph node FRC reprogramming during acute viral infection has remained unexplored. Here, we genetically ablated expression of the type I interferon-α receptor (Ifnar) in Ccl19-Cre+ cells and found that sensing of type I interferon imprints an antiviral state in FRCs and thereby preserves myeloid cell composition in lymph nodes of naive mice. During localized lymphocytic choriomeningitis virus infection, IFNAR signaling precipitated profound phenotypic adaptation of all FRC subsets enhancing antigen presentation, chemokine-driven immune cell recruitment, and immune regulation. The IFNAR-dependent shift of all FRC subsets toward an immunostimulatory state reduced exhaustive CD8+ T cell activation. In sum, these results unveil intricate circuits underlying type I IFN sensing in lymph node FRCs that enable protective antiviral immunity.
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| 5. |
- Rockenfeller, Patrick, et al.
(author)
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Diacylglycerol triggers Rim101 pathway-dependent necrosis in yeast : a model for lipotoxicity
- 2018
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In: Cell Death and Differentiation. - : Springer Science and Business Media LLC. - 1350-9047 .- 1476-5403. ; 25:4, s. 765-781
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Journal article (peer-reviewed)abstract
- The loss of lipid homeostasis can lead to lipid overload and is associated with a variety of disease states. However, little is known as to how the disruption of lipid regulation or lipid overload affects cell survival. In this study we investigated how excess diacylglycerol (DG), a cardinal metabolite suspected to mediate lipotoxicity, compromises the survival of yeast cells. We reveal that increased DG achieved by either genetic manipulation or pharmacological administration of 1,2-dioctanoyls-n-glycerol (DOG) triggers necrotic cell death. The toxic effects of DG are linked to glucose metabolism and require a functional Rim101 signaling cascade involving the Rim21-dependent sensing complex and the activation of a calpain-like protease. The Rim101 cascade is an established pathway that triggers a transcriptional response to alkaline or lipid stress. We propose that the Rim101 pathway senses DG-induced lipid perturbation and conducts a signaling response that either facilitates cellular adaptation or triggers lipotoxic cell death. Using established models of lipotoxicity, i.e., high-fat diet in Drosophila and palmitic acid administration in cultured human endothelial cells, we present evidence that the core mechanism underlying this calpain-dependent lipotoxic cell death pathway is phylogenetically conserved.
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