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- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 5. |
- Hansson, M., et al.
(författare)
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Unique patient with cerebrotendinous xanthomatosis. Evidence for presence of a defect in a gene that is not identical to sterol 27-hydroxylase
- 2007
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Ingår i: Journal of Internal Medicine. - : Wiley. - 1365-2796 .- 0954-6820. ; 261:5, s. 504-510
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Tidskriftsartikel (refereegranskat)abstract
- Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder believed to be exclusively caused by mutations in the CYP27A1 gene coding for the enzyme sterol 27-hydroxylase. Common findings in CTX are tendon xanthomas, cataracts and progressive neurological dysfunction. Here, we characterize an adult female patient with tendon xanthomas and classic biochemical findings of CTX (i.e. high levels of bile alcohols and cholestanol and extremely low levels of 27-hydroxycholesterol in plasma). Additionally, sterol 27-hydroxylase activity in cultured monocyte-derived macrophages from this patient was < 5% of normal. Sequencing the CYP27A1 gene uncovered that the patient is heterozygous for two previously undescribed base substitutions in exon 8, C478A and C479A, which are expected to affect the haeme-binding domain of the enzyme. When expressed in HEK293 cells, the corresponding protein had only 8% of normal enzymatic activity. No other mutation was found in the open reading frame of the CYP27A1 gene, intron-exon boundaries or in the 5'-untranslated region up to 5000 bp distal to the translational start site. Sequencing mRNA isolated from leucocytes from the patient revealed a 1 : 1 ratio of mutated and nonmutated species, with total mRNA levels that were not significantly different from the controls. It is concluded that the patient is heterozygous for two mutations affecting one allele of the CYP27A1 gene and with at least one additional yet undefined gene that is of critical importance for the activity of sterol 27-hydroxylase.
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| 9. |
- von Bahr, V, et al.
(författare)
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Long-term pulmonary function and quality of life in adults after extracorporeal membrane oxygenation for respiratory failure
- 2019
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Ingår i: Perfusion. - : SAGE Publications. - 1477-111X .- 0267-6591. ; 34:1_suppl, s. 49-57
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Tidskriftsartikel (refereegranskat)abstract
- There is a significant long-term burden on survivors after acute respiratory distress syndrome, even 5 years after discharge. This is not well investigated in patients treated with extracorporeal membrane oxygenation. The objective of this study was to describe very-long-term (⩾3 years) disability in lung function and morphology, quality of life, mood disorders, walking capacity, and return to work status in extracorporeal membrane oxygenation survivors. Methods: Single-center retrospective cohort study on long-term survivors treated with extracorporeal membrane oxygenation for respiratory failure between 1995 and 2010 at a tertiary referral center in Sweden. Eligible patients were approached, and those who consented were interviewed and investigated during a day at the hospital. Results: A total of 38 patients were investigated with a median follow-up time of 9.0 years. Quality of life was reduced in several Short form 36 (SF-36) subscales and all domains of the St George’s Respiratory Questionnaire, similar to previous studies in conventionally managed acute respiratory distress syndrome survivors. A reduced diffusion capacity of carbon monoxide was seen in 47% of patients, and some degree of residual lung parenchymal pathology was seen in 82%. Parenchymal pathology correlated with reductions in quality of life and diffusion capacity. Symptoms of anxiety and depression were seen in 22% and 14%, respectively. Conclusion: A significant long-term burden remains even 3–17 years after extracorporeal membrane oxygenation treatment, similar to conventionally managed acute respiratory distress syndrome survivors. Future prospective studies are needed to elucidate risk factors for these sequelae.
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- Bahr, Carsten, et al.
(författare)
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A Myc enhancer cluster regulates normal and leukaemic haematopoietic stem cell hierarchies
- 2018
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 553:7689, s. 515-520
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Tidskriftsartikel (refereegranskat)abstract
- The transcription factor Myc is essential for the regulation of haematopoietic stem cells and progenitors and has a critical function in haematopoietic malignancies1. Here we show that an evolutionarily conserved region located 1.7 megabases downstream of the Myc gene that has previously been labelled as a ‘super-enhancer’2 is essential for the regulation of Myc expression levels in both normal haematopoietic and leukaemic stem cell hierarchies in mice and humans. Deletion of this region in mice leads to a complete loss of Myc expression in haematopoietic stem cells and progenitors. This caused an accumulation of differentiation-arrested multipotent progenitors and loss of myeloid and B cells, mimicking the phenotype caused by Mx1-Cre-mediated conditional deletion of the Myc gene in haematopoietic stem cells3. This super-enhancer comprises multiple enhancer modules with selective activity that recruits a compendium of transcription factors, including GFI1b, RUNX1 and MYB. Analysis of mice carrying deletions of individual enhancer modules suggests that specific Myc expression levels throughout most of the haematopoietic hierarchy are controlled by the combinatorial and additive activity of individual enhancer modules, which collectively function as a ‘blood enhancer cluster’ (BENC). We show that BENC is also essential for the maintenance of MLL–AF9-driven leukaemia in mice. Furthermore, a BENC module, which controls Myc expression in mouse haematopoietic stem cells and progenitors, shows increased chromatin accessibility in human acute myeloid leukaemia stem cells compared to blasts. This difference correlates with MYC expression and patient outcome. We propose that clusters of enhancers, such as BENC, form highly combinatorial systems that allow precise control of gene expression across normal cellular hierarchies and which also can be hijacked in malignancies.
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