| 1. |
- Wang, Z., et al.
(författare)
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Genome-wide association analyses of physical activity and sedentary behavior provide insights into underlying mechanisms and roles in disease prevention
- 2022
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 54:9, s. 1332-1344
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Tidskriftsartikel (refereegranskat)abstract
- Although physical activity and sedentary behavior are moderately heritable, little is known about the mechanisms that influence these traits. Combining data for up to 703,901 individuals from 51 studies in a multi-ancestry meta-analysis of genome-wide association studies yields 99 loci that associate with self-reported moderate-to-vigorous intensity physical activity during leisure time (MVPA), leisure screen time (LST) and/or sedentary behavior at work. Loci associated with LST are enriched for genes whose expression in skeletal muscle is altered by resistance training. A missense variant in ACTN3 makes the alpha-actinin-3 filaments more flexible, resulting in lower maximal force in isolated type IIA muscle fibers, and possibly protection from exercise-induced muscle damage. Finally, Mendelian randomization analyses show that beneficial effects of lower LST and higher MVPA on several risk factors and diseases are mediated or confounded by body mass index (BMI). Our results provide insights into physical activity mechanisms and its role in disease prevention. Multi-ancestry meta-analyses of genome-wide association studies for self-reported physical activity during leisure time, leisure screen time, sedentary commuting and sedentary behavior at work identify 99 loci associated with at least one of these traits.
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| 2. |
- Johansson, Karin C, et al.
(författare)
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Microarray analysis of immune challenged Drosophila hemocytes
- 2005
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 305:1, s. 145-155
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Tidskriftsartikel (refereegranskat)abstract
- nsect hemocytes play multiple roles in immunity and carry out cellular responses like phagocytosis, encapsulation and melanization as well as producing humoral effector proteins in the first line of defense after injury and invasion of microorganisms. In this work, we used the Drosophila melanogaster hemocyte-like cell line mbn-2 and Affymetrix Drosophila GeneChips to investigate the transcriptome of a single type of immune competent tissue exposed to Gram-negative cell wall components (crude LPS) or high dose infection with live Escherichia coli. We found that gene expression profiles of both treatments overlap but show important differences in expression levels of several genes involved in immunity. In addition, cell morphology during infection was monitored and revealed distinct alterations in cell shape and adhesion. Presence of large numbers of bacteria also increased the number of cells taking on crystal cell fate. Taken together, our results indicate that hemocytes sense and respond differently to purified bacterial surface molecules and infection with live and actively growing bacteria both at the level of gene expression and in cell behavior.
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| 3. |
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| 4. |
- Llorens, Jose V., et al.
(författare)
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Mitochondrial iron supply is required for the developmental pulse of ecdysone biosynthesis that initiates metamorphosis in Drosophila melanogaster
- 2015
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Ingår i: Journal of Biological Inorganic Chemistry. - : Springer Science and Business Media LLC. - 0949-8257 .- 1432-1327. ; 20:8, s. 1229-1238
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Tidskriftsartikel (refereegranskat)abstract
- Synthesis of ecdysone, the key hormone that signals the termination of larval growth and the initiation of metamorphosis in insects, is carried out in the prothoracic gland by an array of iron-containing cytochrome P450s, encoded by the halloween genes. Interference, either with iron-sulfur cluster biogenesis in the prothoracic gland or with the ferredoxins that supply electrons for steroidogenesis, causes a block in ecdysone synthesis and developmental arrest in the third instar larval stage. Here we show that mutants in Drosophila mitoferrin (dmfrn), the gene encoding a mitochondrial carrier protein implicated in mitochondrial iron import, fail to grow and initiate metamorphosis under dietary iron depletion or when ferritin function is partially compromised. In mutant dmfrn larvae reared under iron replete conditions, the expression of halloween genes is increased and 20-hydroxyecdysone (20E), the active form of ecdysone, is synthesized. In contrast, addition of an iron chelator to the diet of mutant dmfrn larvae disrupts 20E synthesis. Dietary addition of 20E has little effect on the growth defects, but enables approximately one-third of the iron-deprived dmfrn larvae to successfully turn into pupae and, in a smaller percentage, into adults. This partial rescue is not observed with dietary supply of ecdysone's precursor 7-dehydrocholesterol, a precursor in the ecdysone biosynthetic pathway. The findings reported here support the notion that a physiological supply of mitochondrial iron for the synthesis of iron-sulfur clusters and heme is required in the prothoracic glands of insect larvae for steroidogenesis. Furthermore, mitochondrial iron is also essential for normal larval growth.
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| 5. |
- Mattis, Katia K, et al.
(författare)
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Loss of RREB1 in pancreatic beta cells reduces cellular insulin content and affects endocrine cell gene expression
- 2023
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Ingår i: Diabetologia. - : Springer Nature. - 0012-186X .- 1432-0428. ; 66:4, s. 674-694
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Tidskriftsartikel (refereegranskat)abstract
- AIMS/HYPOTHESIS: Genome-wide studies have uncovered multiple independent signals at the RREB1 locus associated with altered type 2 diabetes risk and related glycaemic traits. However, little is known about the function of the zinc finger transcription factor Ras-responsive element binding protein 1 (RREB1) in glucose homeostasis or how changes in its expression and/or function influence diabetes risk.METHODS: A zebrafish model lacking rreb1a and rreb1b was used to study the effect of RREB1 loss in vivo. Using transcriptomic and cellular phenotyping of a human beta cell model (EndoC-βH1) and human induced pluripotent stem cell (hiPSC)-derived beta-like cells, we investigated how loss of RREB1 expression and activity affects pancreatic endocrine cell development and function. Ex vivo measurements of human islet function were performed in donor islets from carriers of RREB1 type 2 diabetes risk alleles.RESULTS: CRISPR/Cas9-mediated loss of rreb1a and rreb1b function in zebrafish supports an in vivo role for the transcription factor in beta cell mass, beta cell insulin expression and glucose levels. Loss of RREB1 also reduced insulin gene expression and cellular insulin content in EndoC-βH1 cells and impaired insulin secretion under prolonged stimulation. Transcriptomic analysis of RREB1 knockdown and knockout EndoC-βH1 cells supports RREB1 as a novel regulator of genes involved in insulin secretion. In vitro differentiation of RREB1KO/KO hiPSCs revealed dysregulation of pro-endocrine cell genes, including RFX family members, suggesting that RREB1 also regulates genes involved in endocrine cell development. Human donor islets from carriers of type 2 diabetes risk alleles in RREB1 have altered glucose-stimulated insulin secretion ex vivo, consistent with a role for RREB1 in regulating islet cell function.CONCLUSIONS/INTERPRETATION: Together, our results indicate that RREB1 regulates beta cell function by transcriptionally regulating the expression of genes involved in beta cell development and function.
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| 6. |
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| 7. |
- Metzendorf, Christoph, et al.
(författare)
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Characterization of Drosophila mitoferrin and CG18317 mutants
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Mitochondria are the site of iron-sulfur cluster synthesis and insertion of iron into heme, two essential prosthetic groups. Mrs3/4/mitoferrins are mitochondrial carrier proteins, which are involved in the mitochondrial iron transport. Yeast mutants suggest that a low-affinity iron transport system exists. Previous analysis of Drosophila mitoferrin P element mutants revealed an involvement of dmfrn in spermatogenesis. The ubiquitous expression of dmfrn in several adult male tissues, did however suggest a more general role. Results: Here we analyzed stocks with deletions in dmfrn and find that on low iron food dmfrn deletion inhibits development to adulthood, whereas on normal and high iron food some escapers do eclose. RNAi of dmfrn driven by the ubiquitous Actin5C-Gal4 driver recapitulates the phenotype on low iron food, but not on normal or high iron food. Overexpression of dmfrn from an UAS-dmfrn transgenic construct that contains only the coding region of dmfrn also resulted in the failure to develop to adulthood on low iron food. We identified CG18317 as putative Drosophila homolog of yeast Rim2p/Mrs12p, a mitochondrial pyrimidine carrier that is implicated in low affinity iron transport. CG18317 is ubiquitously expressed in several tissues of the male fly and the second exon is alternatively spliced resulting in a 21 nucleotides shorter transcript. An initial study of transposon mutants and deletion mutants of this gene showed sensitivity of one transposon mutant to low iron food conditions. Preliminary results indicate that increased expression of CG18317 might rescue development of dmfrn deletion mutants to at least pupal stage. Conclusions: In contrast to yeast MRS3/4, Drosophila mitoferrin is an essential gene, necessary for development of Drosophila to adulthood. The presence of escapers does however suggest, that dmfrn is either not the only mitochondrial iron carrier or that dmfrn modulates activity of a mitochondrial iron transport system. The sensitivity to low iron conditions of one CG18317 mutant and the partial rescue of dmfrn mutants indicates that this gene could indeed mediate mitochondrial iron uptake in the fly.
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| 8. |
- Metzendorf, Christoph, et al.
(författare)
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Drosophila mitoferrin is essential for male fertility : Evidence for a role of mitochondrial iron metabolism during spermatogenesis
- 2010
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Ingår i: BMC Developmental Biology. - 1471-213X. ; 10, s. 68-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Mammals and Drosophila melanogaster share some striking similarities in spermatogenesis. Mitochondria in spermatids undergo dramatic morphological changes and syncytial spermatids are stripped from their cytoplasm and then individually wrapped by single membranes in an individualization process. In mammalian and fruit fly testis, components of the mitochondrial iron metabolism are expressed, but so far their function during spermatogenesis is unknown. Here we investigate the role of Drosophila mitoferrin (dmfrn), which is a mitochondrial carrier protein with an established role in the mitochondrial iron metabolism, during spermatogenesis.Results: We found that P-element insertions into the 5'-untranslated region of the dmfrn gene cause recessive male sterility, which was rescued by a fluorescently tagged transgenic dmfrn genomic construct (dmfrn(venus)). Testes of mutant homozygous dmfrn(SH115) flies were either small with unorganized content or contained some partially elongated spermatids, or testes were of normal size but lacked mature sperm. Testis squashes indicated that spermatid elongation was defective and electron micrographs showed mitochondrial defects in elongated spermatids and indicated failed individualization. Using a LacZ reporter and the dmfrn(venus) transgene, we found that dmfrn expression in testes was highest in spermatids, coinciding with the stages that showed defects in the mutants. Dmfrn-venus protein accumulated in mitochondrial derivatives of spermatids, where it remained until most of it was stripped off during individualization and disposed of in waste bags. Male sterility in flies with the hypomorph alleles dmfrn(BG00456) and dmfrn(EY01302) over the deletion Df(3R)ED6277 was increased by dietary iron chelation and suppressed by iron supplementation of the food, while male sterility of dmfrn(SH115)/Df(3R)ED6277 flies was not affected by food iron levels.Conclusions: In this work, we show that mutations in the Drosophila mitoferrin gene result in male sterility caused by developmental defects. From the sensitivity of the hypomorph mutants to low food iron levels we conclude that mitochondrial iron is essential for spermatogenesis. This is the first time that a link between the mitochondrial iron metabolism and spermatogenesis has been shown. Furthermore, due to the similar expression patterns of some mitochondrial iron metabolism genes in Drosophila and mammals, it is likely that our results are applicable for mammals as well.
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| 9. |
- Metzendorf, Christoph, 1977-
(författare)
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Mitochondrial Iron Metabolism : Study of mitoferrin in Drosophila melanogaster
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Iron has a dualistic character. On the one hand it is essential for the life of most organisms, on the other hand it is involved in the generation of reactive oxygen species that are implicated in diseases and aging. During evolution efficient mechanisms for uptake, handling and storage of iron in a safe way have developed to keep the balance between iron availability and minimizing the hazards. In eukaryotes, mitochondria are the central organelle for “metabolizing” iron and consequently play an important role in cellular iron homeostasis. Mitoferrins are mitochondrial carrier proteins, which are involved in iron transport into mitochondria. In vertebrates two mitoferrins exist, one (mitoferrin1) of which is essential for heme synthesis during erythropoiesis, while the function of the other (mitoferrin2) is not well defined. In the fruit fly we found only one mitoferrin gene (dmfrn), which codes most likely for a functional homologueof vertebrate mitoferrin2. In Drosophila cell culture, dmfrn overexpression resulted in an overestimation of cell sensed iron levels. The signal responsible for this, is most likely a yet unidentified compound of ISC synthesis. In the cell culture system we also showed that iron chelation blocks the progression of the cell cycle in a reversible and therefore most likely controlled way. Study of different dmfrn mutants indicates a role of dmfrn during spermatogenesis and development to adulthood. As dmfrn deletion mutants are not lethal, it is likely that other lower affinity iron transporters exist. A similar conclusion has been drawn by others from the study of yeast mitoferrin homologuemutants. Rim2p/Mrs12p has recently been implicated in mitochondrial iron transport, and might be an alternative metal carrier. We identified a putative homologuein the fruit fly and found a possible link between mutants in this gene and iron. Our results emphasize the importance of the mitochondrial iron metabolism in cellular iron homeostasis. We also show for the first time, a direct connection between the mitochondrial iron metabolism and spermatogenesis. Mutants characterized and developed by us will help to study these processes in further detail and reveal the underlying mechanisms.
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| 10. |
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| 11. |
- Metzendorf, Christoph, et al.
(författare)
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Mitoferrin is essential for normal development in Drosophila melanogaster
- 2013
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Konferensbidrag (refereegranskat)abstract
- Mitochondria are crucial to iron metabolism, being the unique site for heme synthesis and the major site for iron-sulfur (Fe-S) cluster biosynthesis. Iron is transported into the mitochondrion by an iron metal transporter, mitoferrin, in the inner membrane of mitochondria. By studying different dmfrn Drosophila mutants we have previously showed that dmfrn and mitochondrial iron metabolism have an important role during spermatogenesis and that a functional dmfrn is essential for male fertility (Metzendorf & Lind, 2010). During the spermatogenesis study, we characterized two fly strains with deletions in the dmfrn gene, which is located on the right arm of chromosome three. In the strain with the small deletion dmfrnDf13, which we recovered during P-element mobilization, a third of the 5´ untranslated region is deleted. In the strain Df(3R)ED6277, the genes dmfrn and CG5514 are deleted and half of the 5´ untranslated regions of genes Mes-4 and Gp93 are removed. We found that deletion of dmfrn, (homozygous dmfrnDf13, transheterozygous dmfrnDf13/Df(3R)ED6277 or homozygous Df(3R)ED6277) causes lethality at larval stage.In the current study we analyzed the developmental phenotype in further detail. As fertility of the hypomorph dmfrn P element mutant strains is depended on the level of dietary iron (Metzendorf & Lind, 2010), we were interested if the deletion mutants might show a similar dependence. Using a third chromosome balancer with markers, Tb (Tubby will result in shorter larvae and pupae) and Sb (stubble: bristles short and stubby) that allows distinguishing between heterozygous and transheterozygous flies at the larval, pupal and adult stage makes it possible to quantify the genotypes. We found that transheterozygous (dmfrnDf13/Df(3R)ED6277) flies develop to third instar larvae and very seldom start puparation (<0.25%) when the flies was fed with low iron food. On normal food, transheterozygous flies develop to the pupal stage (~17%), but very few flies eclose as adults (~6%). Knocking down dmfrn expression by Gal4/UAS driven RNA interference (RNAi) with a ubiquitous driver, resulted in a phenotype similar to that of the dmfrn deletion strains. Introduction of the genomic construct dmfrnvenusB32 (a fluorescently (venus) tagged transgenic dmfrn) rescued dmfrn deletion flies to pupal stage on low iron food, and increased the fraction of eclosed adults with the dmfrn deletion alleles on normal and high iron food. The presence of third instar larvae without the balancer indicates that dmfrn deletion might not cause larval lethality, but may either slow down development or cause developmental arrest. We concluded that mitoferrin is essential for normal development and that the developmental phenotype of mitoferrin deletion mutants can be rescued to some degree by addition of dietary iron, showing that the developmental lethality or arrest is due to mitochondrial iron deficiency.Metzendorf , C. and Lind M.I. (2010) Drosophila mitoferrin is essential for male fertility: evidence for a role of mitochondrial iron metabolism during spermatogenesis. BMC Developmental Biology, 10, 68.
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| 12. |
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| 13. |
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| 14. |
- Metzendorf, Christoph, et al.
(författare)
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Overexpression of Drosophila mitoferrin in l(2)mbn cells results in dysregulation of Fer1HCH expression
- 2009
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Ingår i: Biochemical Journal. - 0264-6021 .- 1470-8728. ; 421:Part 3, s. 463-471
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Tidskriftsartikel (refereegranskat)abstract
- Mrs3p and Mrs4p (Mrs3/4p) are yeast mitochondrial iron carrier proteins that play important roles in ISC (iron-sulphur cluster) and haem biosynthesis. At low iron conditions, mitochondrial and cytoplasmic ISC protein maturation is correlated with MRS3/4 expression. Zebrafish mitoferrin1 (mfrn1), one of two MRS3/4 orthologues, is essential for erythropoiesis, but little is known about the ubiquitously expressed paralogue mfrn2. In the present study we identified a single mitoferrin gene (dmfrn) in the genome of Drosophila melanogaster, which is probably an orthologue of mfrn2. Overexpression of dmfrn in the Drosophila l(2)mbn cell line (mbn-dmfrn) resulted in decreased binding between IRP-1A (iron regulatory protein 1A) and stem-loop RNA structures referred to as IREs (iron responsive elements). mbn-dmfrn cell lines also had increased cytoplasmic aconitase activity and slightly decreased iron content. In contrast, iron loading results in decreased IRP-1A-IRE binding, but increased cellular iron content, in experimental mbn-dmfrn and control cell lines. Iron loading also increases cytoplasmic aconitase activity in all cell lines, but with slightly higher activity observed in mbn-dmfrn cells. From this we concluded that dmfrn overexpression stimulates cytoplasmic ISC protein maturation, as has been reported for MRS3/4 overexpression. Compared with control cell lines, mbn-dmfrn cells had higher Fer1HCH (ferritin 1 heavy chain homologue) transcript and protein levels. RNA interference of the putative Drosophila orthologue of human ABCB7, a mitochondrial transporter involved in cytoplasmic ISC protein maturation, restored Fer1HCH transcript levels of iron-treated mbn-dmfrn cells to those of control cells grown in normal medium. These results suggest that dmfrn overexpression in l(2)mbn cells causes an 'overestimation' of the cellular iron content, and that regulation of Fer1HCH transcript abundance probably depends on cytoplasmic ISC protein maturation.
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| 15. |
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| 16. |
- Metzendorf, Christoph, et al.
(författare)
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The role of iron in the proliferation of Drosophila l(2)mbn cells
- 2010
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 400:3, s. 442-446
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Tidskriftsartikel (refereegranskat)abstract
- Iron is essential for life and is needed for cell proliferation and cell cycle progression. Iron deprivation induces cell cycle arrest and finally apoptosis. The Drosophila tumorous larval hemocyte cell line l(2)mbn was used to study the sensitivity and cellular response to iron deprivation through the chelator desferrioxamine (DFO). At a concentration of 10 mM DFO or more the proliferation was inhibited reversibly, while the amount of dead cells did not increase. FACS analysis showed that the cell cycle was arrested in G1/S phase and the transcript level of cycE was decreased to less than 50% of control cells. These results show that iron chelation in this insect tumorous cell line causes a specific and coordinated cell cycle arrest.
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| 17. |
- Metzendorf, Christoph, et al.
(författare)
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Transcriptomic and Proteomic Analysis of Clear Cell Foci (CCF) in the Human Non-Cirrhotic Liver Identifies Several Differentially Expressed Genes and Proteins with Functions in Cancer Cell Biology and Glycogen Metabolism
- 2020
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Ingår i: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 25:18, s. 4141-
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Tidskriftsartikel (refereegranskat)abstract
- Clear cell foci (CCF) of the liver are considered to be pre-neoplastic lesions of hepatocellular adenomas and carcinomas. They are hallmarked by glycogen overload and activation of AKT (v-akt murine thymoma viral oncogene homolog)/mTOR (mammalian target of rapamycin)-signaling. Here, we report the transcriptome and proteome of CCF extracted from human liver biopsies by laser capture microdissection. We found 14 genes and 22 proteins differentially expressed in CCF and the majority of these were expressed at lower levels in CCF. Using immunohistochemistry, the reduced expressions of STBD1 (starch-binding domain-containing protein 1), USP28 (ubiquitin-specific peptidase 28), monad/WDR92 (WD repeat domain 92), CYB5B (Cytochrome b5 type B), and HSPE1 (10 kDa heat shock protein, mitochondrial) were validated in CCF in independent specimens. Knockout of Stbd1, the gene coding for Starch-binding domain-containing protein 1, in mice did not have a significant effect on liver glycogen levels, indicating that additional factors are required for glycogen overload in CCF. Usp28 knockout mice did not show changes in glycogen storage in diethylnitrosamine-induced liver carcinoma, demonstrating that CCF are distinct from this type of cancer model, despite the decreased USP28 expression. Moreover, our data indicates that decreased USP28 expression is a novel factor contributing to the pre-neoplastic character of CCF. In summary, our work identifies several novel and unexpected candidates that are differentially expressed in CCF and that have functions in glycogen metabolism and tumorigenesis.
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| 18. |
- Navarro, Juan A., et al.
(författare)
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Mitoferrin modulates iron toxicity in a Drosophila model of Friedreich's ataxia
- 2015
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Ingår i: Free Radical Biology & Medicine. - : Elsevier BV. - 0891-5849 .- 1873-4596. ; 85, s. 71-82
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Tidskriftsartikel (refereegranskat)abstract
- Friedreich's ataxia is the most important recessive ataxia in the Caucasian population. Loss of frataxin expression affects the production of iron sulfur clusters and, therefore, mitochondrial energy production. One of the pathological consequences is an increase of iron transport into the mitochondrial compartment leading to a toxic accumulation of reactive iron. However, the mechanism underlying this inappropriate mitochondrial iron accumulation is still unknown. Control and frataxin-deficient flies were fed with an iron diet in order to mimic an iron overload and used to assess various cellular as well as mitochondrial functions. We showed that frataxin-deficient flies were hypersensitive toward dietary iron and developed an iron dependent decay of mitochondrial functions. In the fly model exhibiting only partial frataxin loss, we demonstrated that the inability to activate ferritin translation and the enhancement of mitochondrial iron uptake via mitoferrin upregulation were likely the key molecular events behind the iron induced phenotype. Both defects were observed during the normal process of aging, confirming their importance in the progression of the pathology. In an effort to further assess the importance of these mechanisms, we carried out genetic interaction studies. We showed that mitoferrin downregulation improved many of the frataxin-deficient conditions, including nervous system degeneration, whereas mitoferrin overexpression exacerbated most of them. Taken together, this study demonstrates the crucial role of mitoferrin dysfunction in the etiology of Friedreich's ataxia and provides evidence that impairment of mitochondria! iron transport could be an effective treatment of the disease.
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| 19. |
- Nuernberger, Vincent, et al.
(författare)
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Hormonally Induced Hepatocellular Carcinoma in Diabetic Wild Type and Carbohydrate Responsive Element Binding Protein Knockout Mice
- 2021
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Ingår i: Cells. - : MDPI. - 2073-4409. ; 10:10
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Tidskriftsartikel (refereegranskat)abstract
- Objective: In the rat, the pancreatic islet transplantation model is an established method to induce hepatocellular carcinomas (HCC), due to insulin-mediated metabolic and molecular alterations like increased glycolysis and de novo lipogenesis and the oncogenic AKT/mTOR pathway including upregulation of the transcription factor Carbohydrate-response element-binding protein (ChREBP). ChREBP could therefore represent an essential oncogenic co-factor during hormonally induced hepatocarcinogenesis.Methods: Pancreatic islet transplantation was implemented in diabetic C57Bl/6J (wild type, WT) and ChREBP-knockout (KO) mice for 6 and 12 months. Liver tissue was examined using histology, immunohistochemistry, electron microscopy and Western blot analysis. Finally, we performed NGS-based transcriptome analysis between WT and KO liver tumor tissues.Results: Three hepatocellular carcinomas were detectable after 6 and 12 months in diabetic transplanted WT mice, but only one in a KO mouse after 12 months. Pre-neoplastic clear cell foci (CCF) were also present in liver acini downstream of the islets in WT and KO mice. In KO tumors, glycolysis, de novo lipogenesis and AKT/mTOR signalling were strongly downregulated compared to WT lesions. Extrafocal liver tissue of diabetic, transplanted KO mice revealed less glycogen storage and proliferative activity than WT mice. From transcriptome analysis, we identified a set of transcripts pertaining to metabolic, oncogenic and immunogenic pathways that are differentially expressed between tumors of WT and KO mice. Of 315 metabolism-associated genes, we observed 199 genes that displayed upregulation in the tumor of WT mice, whereas 116 transcripts showed their downregulated expression in KO mice tumor.Conclusions: The pancreatic islet transplantation model is a suitable method to study hormonally induced hepatocarcinogenesis also in mice, allowing combination with gene knockout models. Our data indicate that deletion of ChREBP delays insulin-induced hepatocarcinogenesis, suggesting a combined oncogenic and lipogenic function of ChREBP along AKT/mTOR-mediated proliferation of hepatocytes and induction of hepatocellular carcinoma.
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| 20. |
- Porcellato, Elena, et al.
(författare)
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The S-palmitoylome and DHHC-PAT interactome of Drosophila melanogaster S2R+cells indicate a high degree of conservation to mammalian palmitoylomes
- 2022
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 17:8
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Tidskriftsartikel (refereegranskat)abstract
- Protein S-palmitoylation, the addition of a long-chain fatty acid to target proteins, is among the most frequent reversible protein modifications in Metazoa, affecting subcellular protein localization, trafficking and protein-protein interactions. S-palmitoylated proteins are abundant in the neuronal system and are associated with neuronal diseases and cancer. Despite the importance of this post-translational modification, it has not been thoroughly studied in the model organism Drosophila melanogaster. Here we present the palmitoylome of Drosophila S2R+ cells, comprising 198 proteins, an estimated 3.5% of expressed genes in these cells. Comparison of orthologs between mammals and Drosophila suggests that S-palmitoylated proteins are more conserved between these distant phyla than non-S-palmitoylated proteins. To identify putative client proteins and interaction partners of the DHHC family of protein acyl-transferases (PATs) we established DHHC-BioID, a proximity biotinylation-based method. In S2R+ cells, ectopic expression of the DHHC-PAT dHip14-BioID in combination with Snap24 or an interaction-deficient Snap24-mutant as a negative control, resulted in biotinylation of Snap24 but not the Snap24-mutant. DHHC-BioID in S2R+ cells using 10 different DHHC-PATs as bait identified 520 putative DHHC-PAT interaction partners of which 48 were S-palmitoylated and are therefore putative DHHC-PAT client proteins. Comparison of putative client protein/DHHC-PAT combinations indicates that CG8314, CG5196, CG5880 and Patsas have a preference for transmembrane proteins, while S-palmitoylated proteins with the Hip14-interaction motif are most enriched by DHHC-BioID variants of approximated and dHip14. Finally, we show that BioID is active in larval and adult Drosophila and that dHip14-BioID rescues dHip14 mutant flies, indicating that DHHC-BioID is non-toxic. In summary we provide the first systematic analysis of a Drosophila palmitoylome. We show that DHHC-BioID is sensitive and specific enough to identify DHHC-PAT client proteins and provide DHHC-PAT assignment for ca. 25% of the S2R+ cell palmitoylome, providing a valuable resource. In addition, we establish DHHC-BioID as a useful concept for the identification of tissue-specific DHHC-PAT interactomes in Drosophila.
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