@article{KorovilaHoehnJungetal.2021, author = {Korovila, Ioanna and Hoehn, Annika and Jung, Tobias and Grune, Tilman and Ott, Christiane}, title = {Reduced liver autophagy in high-fat diet induced liver steatosis in New Zealand obese mice}, series = {Antioxidants : open access journal}, volume = {10}, journal = {Antioxidants : open access journal}, number = {4}, publisher = {MDPI}, address = {Basel}, issn = {2076-3921}, doi = {10.3390/antiox10040501}, pages = {10}, year = {2021}, abstract = {Non-alcoholic fatty liver disease (NAFLD), as a consequence of overnutrition caused by high-calorie diets, results in obesity and disturbed lipid homeostasis leading to hepatic lipid droplet formation. Lipid droplets can impair hepatocellular function; therefore, it is of utmost importance to degrade these cellular structures. This requires the normal function of the autophagic-lysosomal system and the ubiquitin-proteasomal system. We demonstrated in NZO mice, a polygenic model of obesity, which were compared to C57BL/6J (B6) mice, that a high-fat diet leads to obesity and accumulation of lipid droplets in the liver. This was accompanied by a loss of autophagy efficiency whereas the activity of lysosomal proteases and the 20S proteasome remained unaffected. The disturbance of cellular protein homeostasis was further demonstrated by the accumulation of 3-nitrotyrosine and 4-hydroxynonenal modified proteins, which are normally prone to degradation. Therefore, we conclude that fat accumulation in the liver due to a high-fat diet is associated with a failure of autophagy and leads to the disturbance of proteostasis. This might further contribute to lipid droplet stabilization and accumulation.}, language = {en} } @article{GilCoullJonasetal.2022, author = {Gil, Carla Igual and Coull, Bethany M. and Jonas, Wenke and Lippert, Rachel N. and Klaus, Susanne and Ost, Mario}, title = {Mitochondrial stress-induced GFRAL signaling controls diurnal food intake and anxiety-like behavior}, series = {Life Science Alliance}, volume = {5}, journal = {Life Science Alliance}, number = {11}, publisher = {EMBO Press}, address = {Heidelberg}, issn = {2575-1077}, doi = {10.26508/lsa.202201495}, pages = {11}, year = {2022}, abstract = {Growth differentiation factor 15 (GDF15) is a mitochondrial stressinduced cytokine that modulates energy balance in an endocrine manner. However, the importance of its brainstem-restricted receptor GDNF family receptor alpha-like (GFRAL) to mediate endocrine GDF15 signaling to the brain uponmitochondrial dysfunction is still unknown. Using a mouse model with muscle-specific mitochondrial dysfunction, we here show that GFRAL is required for activation of systemic energy metabolism via daytime-restricted anorexia but not responsible for muscle wasting. We further find that muscle mitochondrial stress response involves a GFRAL-dependent induction of hypothalamic corticotropin-releasing hormone, without elevated corticosterone levels. Finally, we identify that GFRAL signaling governs an anxiety-like behavior in male mice with muscle mitochondrial dysfunction, with females showing a less robust GFRAL-dependent anxiety-like phenotype. Together, we here provide novel evidence of a mitochondrial stress-induced muscle-brain crosstalk via the GDF15-GFRAL axis to modulate food intake and anxiogenic behavior.}, language = {en} } @article{WittekToumaNitezkietal.2023, author = {Wittek, Laura and Touma, Chadi and Nitezki, Tina and Laeger, Thomas and Kr{\"a}mer, Stephanie and Raila, Jens}, title = {Reduction in cold stress in an innovative metabolic cage housing system increases animal welfare in laboratory mice}, series = {Animals}, volume = {13}, journal = {Animals}, number = {18}, publisher = {MDPI}, address = {Basel}, issn = {2076-2615}, doi = {10.3390/ani13182866}, pages = {21}, year = {2023}, abstract = {Housing in metabolic cages can induce a pronounced stress response. Metabolic cage systems imply housing mice on metal wire mesh for the collection of urine and feces in addition to monitoring food and water intake. Moreover, mice are single-housed, and no nesting, bedding, or enrichment material is provided, which is often argued to have a not negligible impact on animal welfare due to cold stress. We therefore attempted to reduce stress during metabolic cage housing for mice by comparing an innovative metabolic cage (IMC) with a commercially available metabolic cage from Tecniplast GmbH (TMC) and a control cage. Substantial refinement measures were incorporated into the IMC cage design. In the frame of a multifactorial approach for severity assessment, parameters such as body weight, body composition, food intake, cage and body surface temperature (thermal imaging), mRNA expression of uncoupling protein 1 (Ucp1) in brown adipose tissue (BAT), fur score, and fecal corticosterone metabolites (CMs) were included. Female and male C57BL/6J mice were single-housed for 24 h in either conventional Macrolon cages (control), IMC, or TMC for two sessions. Body weight decreased less in the IMC (females—1st restraint: -6.94\%; 2nd restraint: -6.89\%; males—1st restraint: -8.08\%; 2nd restraint: -5.82\%) compared to the TMC (females—1st restraint: -13.2\%; 2nd restraint: -15.0\%; males—1st restraint: -13.1\%; 2nd restraint: -14.9\%) and the IMC possessed a higher cage temperature (females—1st restraint: 23.7 °C; 2nd restraint: 23.5 °C; males—1st restraint: 23.3 °C; 2nd restraint: 23.5 °C) compared with the TMC (females—1st restraint: 22.4 °C; 2nd restraint: 22.5 °C; males—1st restraint: 22.6 °C; 2nd restraint: 22.4 °C). The concentration of fecal corticosterone metabolites in the TMC (females—1st restraint: 1376 ng/g dry weight (DW); 2nd restraint: 2098 ng/g DW; males—1st restraint: 1030 ng/g DW; 2nd restraint: 1163 ng/g DW) was higher compared to control cage housing (females—1st restraint: 640 ng/g DW; 2nd restraint: 941 ng/g DW; males—1st restraint: 504 ng/g DW; 2nd restraint: 537 ng/g DW). Our results show the stress potential induced by metabolic cage restraint that is markedly influenced by the lower housing temperature. The IMC represents a first attempt to target cold stress reduction during metabolic cage application thereby producing more animal welfare friendlydata.}, language = {en} } @article{RadbruchPischonDuetal.2022, author = {Radbruch, Moritz Jan Florian and Pischon, Jeanette Hannah Charlotte and Du, Fang and Haag, Rainer and Schumacher, Fabian and Kleuser, Burkhard and Mundhenk, Lars and Gruber, Achim}, title = {Biodegradable core-multishell nanocarrier: topical tacrolimus delivery for treatment of dermatitis}, series = {Journal of controlled release : official journal of the Controlled Release Society and of the Japanese Society of Drug Delivery Systems}, volume = {349}, journal = {Journal of controlled release : official journal of the Controlled Release Society and of the Japanese Society of Drug Delivery Systems}, publisher = {Elsevier}, address = {New York, NY [u.a.]}, issn = {0168-3659}, doi = {10.1016/j.jconrel.2022.07.025}, pages = {917 -- 928}, year = {2022}, abstract = {Two challenges in topical drug delivery to the skin include solubilizing hydrophobic drugs in water-based formulations and increasing drug penetration into the skin. Polymeric core-multishell nanocarrier (CMS), particularly the novel biodegradable CMS (bCMS = hPG-PCL1.1K-mPEG(2k)-CMS) have shown both advantages on excised skin ex vivo. Here, we investigated topical delivery of tacrolimus (TAC; > 500 g/mol) by bCMS in a hydrogel on an oxazolone-induced model of dermatitis in vivo. As expected, bCMS successfully delivered TAC into the skin. However, in vivo they did not increase, but decrease TAC penetration through the stratum corneum compared to ointment. Differences in the resulting mean concentrations were mostly non-significant in the skin (epidermis: 35.7 +/- 20.9 ng/cm(2) for bCMS vs. 92.6 +/- 62.7 ng/cm(2) for ointment; dermis: 76.8 +/- 26.8 ng/cm(2) vs 118.2 +/- 50.4 ng/cm(2)), but highly significant in blood (plasma: 1.1 +/- 0.4 ng/ml vs 11.3 +/- 9.3 ng/ml; erythrocytes: 0.5 +/- 0.2 ng/ml vs 3.4 +/- 2.4 ng/ml) and liver (0.01 +/- 0.01 ng/mg vs 0.03 +/- 0.01 ng/mg). bCMS were detected in the stratum corneum but not in viable skin or beyond. The therapeutic efficacy of TAC delivered by bCMS was equivalent to that of standard TAC ointment. Our results suggest that bCMS may be a promising carrier for the topical delivery of TAC. The quantitative difference to previous results should be interpreted in light of structural differences between murine and human skin, but highlights the need as well as potential methods to develop more a complex ex vivo analysis on human skin to ensure quantitative predictive value.}, language = {en} } @article{JonasSchwerbelZellneretal.2022, author = {Jonas, Wenke and Schwerbel, Kristin and Zellner, Lisa and J{\"a}hnert, Markus and Gottmann, Pascal and Sch{\"u}rmann, Annette}, title = {Alterations of lipid profile in livers with impaired lipophagy}, series = {International journal of molecular sciences}, volume = {23}, journal = {International journal of molecular sciences}, number = {19}, publisher = {MDPI}, address = {Basel}, issn = {1422-0067}, doi = {10.3390/ijms231911863}, pages = {12}, year = {2022}, abstract = {Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation in the liver. Various mechanisms such as an increased uptake in fatty acids or de novo synthesis contribute to the development of steatosis and progression to more severe stages. Furthermore, it has been shown that impaired lipophagy, the degradation of lipids by autophagic processes, contributes to NAFLD. Through an unbiased lipidome analysis of mouse livers in a genetic model of impaired lipophagy, we aimed to determine the resulting alterations in the lipidome. Observed changes overlap with those of the human disease. Overall, the entire lipid content and in particular the triacylglycerol concentration increased under conditions of impaired lipophagy. In addition, we detected a reduction in long-chain polyunsaturated fatty acids (PUFAs) and an increased ratio of n-6 PUFAs to n-3 PUFAs, which was due to the depletion of n-3 PUFAs. Although the abundance of major phospholipid classes was reduced, the ratio of phosphatidylcholines to phosphatidylethanolamines was not affected. In conclusion, this study demonstrates that impaired lipophagy contributes to the pathology of NAFLD and is associated with an altered lipid profile. However, the lipid pattern does not appear to be specific for lipophagic alterations, as it resembles mainly that described in relation to fatty liver disease.}, language = {en} } @article{HuschekRawelSchweikertetal.2022, author = {Huschek, Gerd and Rawel, Harshadrai M. and Schweikert, Torsten and Henkel-Oberl{\"a}nder, Janin and Sagu Tchewonpi, Sorel}, title = {Characterization and optimization of microwave-assisted extraction of B-phycoerythrin from Porphyridium purpureum using response surface methodology and Doehlert design}, series = {Bioresource Technology Reports}, volume = {19}, journal = {Bioresource Technology Reports}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2589-014X}, doi = {10.1016/j.biteb.2022.101212}, pages = {9}, year = {2022}, abstract = {Microalgae are one of the most promising food source of the future. Nowadays, extracts of high-value active substances of biomass are business aims for the development of food additives in personalized nutrition, in cosmetics and pharmaceuticals. A new-patented vertical farming cultivation technology was used for production of Porphyridium purpureum. In this work, microwave assisted extraction was used to extract B-phycoerythrin from Porphyridium purpureum biomass. Response surface methodology was implemented for optimization. Numerical optimization established the best point of the experimental domain (biomass/solvent of 16.8 mg/mL, time of 172 s, and temperature of 30 degrees C) with a desirability value of 0.82. Corresponding experimental responses values of 7.2 mg, 8.5 \% and 13,961 PA/mu g biomass were obtained for extracted proteins, extraction yield and extracted B-phycoerythrin, respectively. Final freeze-dried product indicated protein content of 55 \% using Kjeldahl while targeted mass spectrometry analysis revealed that B-phycoerythrin represented 93 \% of the total protein.}, language = {en} } @article{RuszkiewiczPapatheodorouJaecketal.2023, author = {Ruszkiewicz, Joanna and Papatheodorou, Ylea and J{\"a}ck, Nathalie and Melzig, Jasmin and Eble, Franziska and Pirker, Annika and Thomann, Marius and Haberer, Andreas and Rothmiller, Simone and B{\"u}rkle, Alexander and Mangerich, Aswin}, title = {NAD+ Acts as a protective factor in cellular stress response to DNA alkylating agents}, series = {Cells : open access journal}, volume = {12}, journal = {Cells : open access journal}, number = {19}, publisher = {MDPI}, address = {Basel}, issn = {2073-4409}, doi = {10.3390/cells12192396}, pages = {22}, year = {2023}, abstract = {Sulfur mustard (SM) and its derivatives are potent genotoxic agents, which have been shown to trigger the activation of poly (ADP-ribose) polymerases (PARPs) and the depletion of their substrate, nicotinamide adenine dinucleotide (NAD+). NAD+ is an essential molecule involved in numerous cellular pathways, including genome integrity and DNA repair, and thus, NAD+ supplementation might be beneficial for mitigating mustard-induced (geno)toxicity. In this study, the role of NAD+ depletion and elevation in the genotoxic stress response to SM derivatives, i.e., the monofunctional agent 2-chloroethyl-ethyl sulfide (CEES) and the crosslinking agent mechlorethamine (HN2), was investigated with the use of NAD+ booster nicotinamide riboside (NR) and NAD+ synthesis inhibitor FK866. The effects were analyzed in immortalized human keratinocytes (HaCaT) or monocyte-like cell line THP-1. In HaCaT cells, NR supplementation, increased NAD+ levels, and elevated PAR response, however, did not affect ATP levels or DNA damage repair, nor did it attenuate long- and short-term cytotoxicities. On the other hand, the depletion of cellular NAD+ via FK866 sensitized HaCaT cells to genotoxic stress, particularly CEES exposure, whereas NR supplementation, by increasing cellular NAD+ levels, rescued the sensitizing FK866 effect. Intriguingly, in THP-1 cells, the NR-induced elevation of cellular NAD+ levels did attenuate toxicity of the mustard compounds, especially upon CEES exposure. Together, our results reveal that NAD+ is an important molecule in the pathomechanism of SM derivatives, exhibiting compound-specificity. Moreover, the cell line-dependent protective effects of NR are indicative of system-specificity of the application of this NAD+ booster.}, language = {en} } @article{SaguTchewonpiRawelRohn2022, author = {Sagu Tchewonpi, Sorel and Rawel, Harshadrai M. and Rohn, Sascha}, title = {Targeted bottom-up mass spectrometry approach for the relative quantification of post-translational modification of bovine κ-casein during milk fermentation}, series = {Molecules}, volume = {27}, journal = {Molecules}, number = {18}, publisher = {MDPI}, address = {Basel}, issn = {1420-3049}, doi = {10.3390/molecules27185834}, pages = {17}, year = {2022}, abstract = {kappa-casein (kappa-CN) is one of the key components in bovine milk, playing a unique role in the structuration of casein micelles. It contains in its chemical structure up to sixteen amino acid residues (mainly serine and threonine) susceptible to modifications, including glycosylation and phosphorylation, which may further be formed during milk processing. In this study, changes in post-translational modification (PTM) of kappa-CN during bovine milk fermentation were investigated. One-to-five-day fermented milk samples were produced. A traditional bottom-up proteomics approach was used to establish a multiple-reaction monitoring (MRM) method for relative quantification of kappa-CN PTM. Endoproteinase Glu-C was found to efficiently digest the kappa-CN molecule. The developed LC-MS method was validated by performing assessments of linearity, precision, repeatability, reproducibility, limit of detection (LOD), and limit of quantification (LOQ). Among the yielded peptides, four of them containing serine and threonine residues were identified and the unmodified as well as the modified variants of each of them were relatively quantified. These peptides were (1) IPTINTIASGEPTSTTE ([140, 158]), (2) STVATLE ([162, 168]), (3) DSPE ([169, 172]), and (4) INTVQVTSTAV ([180, 190]). Distribution analysis between unmodified and modified peptides revealed that over 50\% of kappa-CN was found in one of its modified forms in milk. The fermentation process further significantly altered the composition between unmodified/modified kappa-CN, with glycoslaytion being predominant compared to phosphorylation (p < 0.01). Further method development towards alpha and beta-CN fractions and their PTM behavior would be an asset to better understand the changes undergone by milk proteins and the micellar structure during fermentation.}, language = {en} } @inproceedings{SchulzeDoeschnerGoegeretal.2022, author = {Schulze, Kora and D{\"o}schner, Larissa and G{\"o}ger, Lea and Franz, K. and M{\"u}ller-Werdan, Ursula and Norman, Kristina and Herpich, Catrin}, title = {Kurzeitige vegane Intervention senkt Inflammationsmarker}, series = {Zeitschrift f{\"u}r Gerontologie und Geriatrie : Organ der Deutschen Gesellschaft f{\"u}r Gerontologie und Geriatrie}, volume = {55}, booktitle = {Zeitschrift f{\"u}r Gerontologie und Geriatrie : Organ der Deutschen Gesellschaft f{\"u}r Gerontologie und Geriatrie}, number = {Supplement 1}, publisher = {Springer Medizin}, address = {Heidelberg}, issn = {0948-6704}, doi = {10.1007/s00391-022-02095-7}, pages = {S83 -- S84}, year = {2022}, language = {de} } @phdthesis{Friese2024, author = {Friese, Sharleen}, title = {Trace elements and genomic instability in the murine brain}, school = {Universit{\"a}t Potsdam}, pages = {XV, 112, XXI}, year = {2024}, abstract = {The trace elements copper, iron, manganese, selenium and zinc are essential micronutrients involved in various cellular processes, all with different responsibilities. Based on that importance, their concentrations are tightly regulated in mammalian organisms. The maintenance of those levels is termed trace element homeostasis and mediated by a combination of processes regulating absorption, cellular and systemic transport mechanisms, storage and effector proteins as well as excretion. Due to their chemical properties, some functions of trace elements overlap, as seen in antioxidative defence, for example, comprising an expansive spectrum of antioxidative proteins and molecules. Simultaneously, the same is true for regulatory mechanisms, causing trace elements to influence each other's homeostases. To mimic physiological conditions, trace elements should therefore not be evaluated separately but considered in parallel. While many of these homeostatic mechanisms are well-studied, for some elements new pathways are still discovered. Additionally, the connections between dietary trace element intake, trace element status and health are not fully unraveled, yet. With current demographic developments, also the influence of ageing as well as of certain pathological conditions is of increasing interest. Here, the TraceAge research unit was initiated, aiming to elucidate the homeostases of and interactions between essential trace elements in healthy and diseased elderly. While human cohort studies can offer insights into trace element profiles, also in vivo model organisms are used to identify underlying molecular mechanisms. This is achieved by a set of feeding studies including mice of various age groups receiving diets of reduced trace element content. To account for cognitive deterioration observed with ageing, neurodegenerative diseases, as well as genetic mutations triggering imbalances in cerebral trace element concentrations, one TraceAge work package focuses on trace elements in the murine brain, specifically the cerebellum. In that context, concentrations of the five essential trace elements of interest, copper, iron, manganese, selenium and zinc, were quantified via inductively coupled plasma-tandem mass spectrometry, revealing differences in priority of trace element homeostases between brain and liver. Upon moderate reduction of dietary trace element supply, cerebellar concentrations of copper and manganese deviated from those in adequately supplied animals. By further reduction of dietary trace element contents, also concentrations of cerebellar iron and selenium were affected, but not as strong as observed in liver tissue. In contrast, zinc concentrations remained stable. Investigation of aged mice revealed cerebellar accumulation of copper and iron, possibly contributing to oxidative stress on account of their redox properties. Oxidative stress affects a multitude of cellular components and processes, among them, next to proteins and lipids, also the DNA. Direct insults impairing its integrity are of relevance here, but also indirect effects, mediated by the machinery ensuring genomic stability and its functionality. The system includes the DNA damage response, comprising detection of endogenous and exogenous DNA lesions, decision on subsequent cell fate and enabling DNA repair, which presents another pillar of genomic stability maintenance. Also in proteins of this machinery, trace elements act as cofactors, shaping the hypothesis of impaired genomic stability maintenance under conditions of disturbed trace element homeostasis. To investigate this hypothesis, a variety of approaches was used, applying OECD guidelines Organisation for Economic Co-operation and Development, adapting existing protocols for use in cerebellum tissue and establishing new methods. In order to assess the impact of age and dietary trace element depletion on selected endpoints estimating genomic instability, DNA damage and DNA repair were investigated. DNA damage analysis, in particular of DNA strand breaks and oxidatively modified DNA bases, revealed stable physiological levels which were neither affected by age nor trace element supply. To examine whether this is a result of increased repair rates, two steps characteristic for base excision repair, namely DNA incision and ligation activity, were studied. DNA glycosylases and DNA ligases were not reduced in their activity by age or trace element depletion, either. Also on the level of gene expression, major proteins involved in genomic stability maintenance were analysed, mirroring results obtained from protein studies. To conclude, the present work describes homeostatic regulation of trace elements in the brain, which, in absence of genetic mutations, is able to retain physiological levels even under conditions of reduced trace element supply to a certain extent. This is reflected by functionality of genomic stability maintenance mechanisms, illuminating the prioritization of the brain as vital organ.}, language = {en} }