TY  - JOUR
A1  - Wardelmann, Kristina
A1  - Rath, Michaela
A1  - Castro, José Pedro
A1  - Blümel, Sabine
A1  - Schell, Mareike
A1  - Hauffe, Robert
A1  - Schumacher, Fabian
A1  - Flore, Tanina
A1  - Ritter, Katrin
A1  - Wernitz, Andreas
A1  - Hosoi, Toru
A1  - Ozawa, Koichiro
A1  - Kleuser, Burkhard
A1  - Weiß, Jürgen
A1  - Schürmann, Annette
A1  - Kleinridders, André
T1  - Central acting Hsp10 regulates mitochondrial function, fatty acid metabolism and insulin sensitivity in the hypothalamus
JF  - Antioxidants
N2  - Mitochondria are critical for hypothalamic function and regulators of metabolism. Hypothalamic mitochondrial dysfunction with decreased mitochondrial chaperone expression is present in type 2 diabetes (T2D). Recently, we demonstrated that a dysregulated mitochondrial stress response (MSR) with reduced chaperone expression in the hypothalamus is an early event in obesity development due to insufficient insulin signaling. Although insulin activates this response and improves metabolism, the metabolic impact of one of its members, the mitochondrial chaperone heat shock protein 10 (Hsp10), is unknown. Thus, we hypothesized that a reduction of Hsp10 in hypothalamic neurons will impair mitochondrial function and impact brain insulin action. Therefore, we investigated the role of chaperone Hsp10 by introducing a lentiviral-mediated Hsp10 knockdown (KD) in the hypothalamic cell line CLU-183 and in the arcuate nucleus (ARC) of C57BL/6N male mice. We analyzed mitochondrial function and insulin signaling utilizing qPCR, Western blot, XF96 Analyzer, immunohistochemistry, and microscopy techniques. We show that Hsp10 expression is reduced in T2D mice brains and regulated by leptin in vitro. Hsp10 KD in hypothalamic cells induced mitochondrial dysfunction with altered fatty acid metabolism and increased mitochondria-specific oxidative stress resulting in neuronal insulin resistance. Consequently, the reduction of Hsp10 in the ARC of C57BL/6N mice caused hypothalamic insulin resistance with acute liver insulin resistance.
KW  - brain insulin signaling
KW  - mitochondria
KW  - oxidative stress
KW  - fatty acid metabolism
Y1  - 2021
U6  - https://doi.org/10.3390/antiox10050711
SN  - 2076-3921
VL  - 10
IS  - 5
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Keller, Johannes
A1  - Catala-Lehnen, Philip
A1  - Huebner, Antje K.
A1  - Jeschke, Anke
A1  - Heckt, Timo
A1  - Lueth, Anja
A1  - Krause, Matthias
A1  - Koehne, Till
A1  - Albers, Joachim
A1  - Schulze, Jochen
A1  - Schilling, Sarah
A1  - Haberland, Michael
A1  - Denninger, Hannah
A1  - Neven, Mona
A1  - Hermans-Borgmeyer, Irm
A1  - Streichert, Thomas
A1  - Breer, Stefan
A1  - Barvencik, Florian
A1  - Levkau, Bodo
A1  - Rathkolb, Birgit
A1  - Wolf, Eckhard
A1  - Calzada-Wack, Julia
A1  - Neff, Frauke
A1  - Gailus-Durner, Valerie
A1  - Fuchs, Helmut
A1  - de Angelis, Martin Hrabe
A1  - Klutmann, Susanne
A1  - Tsourdi, Elena
A1  - Hofbauer, Lorenz C.
A1  - Kleuser, Burkhard
A1  - Chun, Jerold
A1  - Schinke, Thorsten
A1  - Amling, Michael
T1  - Calcitonin controls bone formation by inhibiting the release of sphingosine 1-phosphate from osteoclasts
JF  - Nature Communications
N2  - The hormone calcitonin (CT) is primarily known for its pharmacologic action as an inhibitor of bone resorption, yet CT-deficient mice display increased bone formation. These findings raised the question about the underlying cellular and molecular mechanism of CT action. Here we show that either ubiquitous or osteoclast-specific inactivation of the murine CT receptor (CTR) causes increased bone formation. CT negatively regulates the osteoclast expression of Spns2 gene, which encodes a transporter for the signalling lipid sphingosine 1-phosphate (S1P). CTR-deficient mice show increased S1P levels, and their skeletal phenotype is normalized by deletion of the S1P receptor S1P(3). Finally, pharmacologic treatment with the nonselective S1P receptor agonist FTY720 causes increased bone formation in wild-type, but not in S1P(3)-deficient mice. This study redefines the role of CT in skeletal biology, confirms that S1P acts as an osteoanabolic molecule in vivo and provides evidence for a pharmacologically exploitable crosstalk between osteoclasts and osteoblasts.
Y1  - 2014
U6  - https://doi.org/10.1038/ncomms6215
SN  - 2041-1723
VL  - 5
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Henze, Andrea
A1  - Homann, Thomas
A1  - Rohn, Isabelle
A1  - Aschner, Michael A.
A1  - Link, Christopher D.
A1  - Kleuser, Burkhard
A1  - Schweigert, Florian J.
A1  - Schwerdtle, Tanja
A1  - Bornhorst, Julia
T1  - Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin
JF  - Scientific reports
N2  - The visceral protein transthyretin (TTR) is frequently affected by oxidative post-translational protein modifications (PTPMs) in various diseases. Thus, better insight into structure-function relationships due to oxidative PTPMs of TTR should contribute to the understanding of pathophysiologic mechanisms. While the in vivo analysis of TTR in mammalian models is complex, time-and resource-consuming, transgenic Caenorhabditis elegans expressing hTTR provide an optimal model for the in vivo identification and characterization of drug-mediated oxidative PTPMs of hTTR by means of matrix assisted laser desorption/ionization - time of flight - mass spectrometry (MALDI-TOF-MS). Herein, we demonstrated that hTTR is expressed in all developmental stages of Caenorhabditis elegans, enabling the analysis of hTTR metabolism during the whole life-cycle. The suitability of the applied model was verified by exposing worms to D-penicillamine and menadione. Both drugs induced substantial changes in the oxidative PTPM pattern of hTTR. Additionally, for the first time a covalent binding of both drugs with hTTR was identified and verified by molecular modelling.
Y1  - 2016
U6  - https://doi.org/10.1038/srep37346
SN  - 2045-2322
VL  - 6
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Henze, Andrea
A1  - Homann, Thomas
A1  - Rohn, Isabelle
A1  - Aschner, Michael A.
A1  - Link, Christopher D.
A1  - Kleuser, Burkhard
A1  - Schweigert, Florian J.
A1  - Schwerdtle, Tanja
A1  - Bornhorst, Julia
T1  - Caenorhabditis elegans as a model system to study post-translational modifications of human transthyretin
JF  - Scientific reports
N2  - The visceral protein transthyretin (TTR) is frequently affected by oxidative post-translational protein modifications (PTPMs) in various diseases. Thus, better insight into structure-function relationships due to oxidative PTPMs of TTR should contribute to the understanding of pathophysiologic mechanisms. While the in vivo analysis of TTR in mammalian models is complex, time- and resource-consuming, transgenic Caenorhabditis elegans expressing hTTR provide an optimal model for the in vivo identification and characterization of drug-mediated oxidative PTPMs of hTTR by means of matrix assisted laser desorption/ionization – time of flight – mass spectrometry (MALDI-TOF-MS). Herein, we demonstrated that hTTR is expressed in all developmental stages of Caenorhabditis elegans, enabling the analysis of hTTR metabolism during the whole life-cycle. The suitability of the applied model was verified by exposing worms to D-penicillamine and menadione. Both drugs induced substantial changes in the oxidative PTPM pattern of hTTR. Additionally, for the first time a covalent binding of both drugs with hTTR was identified and verified by molecular modelling.
KW  - n-acetyl-cysteine
KW  - s-glutathionylation
KW  - force-field
KW  - c. elegans
KW  - life-span
KW  - protein
KW  - cells
KW  - menadione
KW  - disease
KW  - binding
Y1  - 2016
U6  - https://doi.org/10.1038/srep37346
SN  - 2045-2322
VL  - 6
PB  - Nature Publishing Group
CY  - London
ER  - 
TY  - JOUR
A1  - Beckmann, Nadine
A1  - Schumacher, Fabian
A1  - Kleuser, Burkhard
A1  - Gulbins, Erich
A1  - Nomellini, Vanessa
A1  - Caldwell, Charles C.
T1  - Burn injury impairs neutrophil chemotaxis through increased ceramide
JF  - Shock : injury, inflammation, and sepsis, laboratory and clinical approaches
N2  - Infection is a common and often deadly complication after burn injury. A major underlying factor is burn-induced immune dysfunction, particularly with respect to neutrophils as the primary responders to infection. Temporally after murine scald injury, we demonstrate impaired bone marrow neutrophil chemotaxis toward CXCL1 ex vivo. Additionally, we observed a reduced recruitment of neutrophils to the peritoneal after elicitation 7 days after injury. We demonstrate that neutrophil ceramide levels increase after burn injury, and this is associated with decreased expression of CXCR2 and blunted chemotaxis. A major signaling event upon CXCR2 activation is Akt phosphorylation and this was reduced when ceramide was elevated. In contrast, PTEN levels were elevated and PTEN-inhibition elevated phospho-Akt levels and mitigated the burn-induced neutrophil chemotaxis defect. Altogether, this study identifies a newly described pathway of ceramide-mediated suppression of neutrophil chemotaxis after burn injury and introduces potential targets to mitigate this defect and reduce infection-related morbidity and mortality after burn.
KW  - Acid sphingomyelinase
KW  - Akt
KW  - burn injury
KW  - ceramide
KW  - CXCR2
KW  - immune
KW  - dysfunction
KW  - neutrophil chemotaxis
KW  - PTEN
Y1  - 2021
U6  - https://doi.org/10.1097/SHK.0000000000001693
SN  - 1073-2322
SN  - 1540-0514
VL  - 56
IS  - 1
SP  - 125
EP  - 132
PB  - Lippincott Williams & Wilkins
CY  - Hagerstown, Md.
ER  - 
TY  - JOUR
A1  - Giulbudagian, Michael
A1  - Yealland, Guy
A1  - Hönzke, S.
A1  - Edlich, A.
A1  - Geisendörfer, Birte
A1  - Kleuser, Burkhard
A1  - Hedtrich, Sarah
A1  - Calderon, Marcelo
T1  - Breaking the Barrier
BT  - potent anti-inflammatory activity following efficient topical delivery of etanercept using thermoresponsive nanogels
JF  - Theranostics
N2  - Topical administration permits targeted, sustained delivery of therapeutics to human skin. Delivery to the skin, however, is typically limited to lipophilic molecules with molecular weight of < 500 Da, capable of crossing the stratum corneum. Nevertheless, there are indications protein delivery may be possible in barrier deficient skin, a condition found in several inflammatory skin diseases such as psoriasis, using novel nanocarrier systems. Methods: Water in water thermo-nanoprecipitation; dynamic light scattering; zeta potential measurement; nanoparticle tracking analysis; atomic force microscopy; cryogenic transmission electron microscopy; UV absorption; centrifugal separation membranes; bicinchoninic acid assay; circular dichroism; TNF alpha binding ELISA; inflammatory skin equivalent construction; human skin biopsies; immunohistochemistry; fluorescence microscopy; western blot; monocyte derived Langerhans cells; ELISA Results: Here, we report the novel synthesis of thermoresponsive nanogels (tNG) and the stable encapsulation of the anti-TNFa fusion protein etanercept (ETR) (similar to 150 kDa) without alteration to its structure, as well as temperature triggered release from the tNGs. Novel tNG synthesis without the use of organic solvents was conducted, permitting in situ encapsulation of protein during assembly, something that holds great promise for easy manufacture and storage. Topical application of ETR loaded tNGs to inflammatory skin equivalents or tape striped human skin resulted in efficient ETR delivery throughout the SC and into the viable epidermis that correlated with clear anti-inflammatory effects. Notably, effective ETR delivery depended on temperature triggered release following topical application. Conclusion: Together these results indicate tNGs hold promise as a biocompatible and easy to manufacture vehicle for stable protein encapsulation and topical delivery into barrier-deficient skin.
KW  - thermoresponsive-nanogel
KW  - topical
KW  - anti-inflammatory therapy
KW  - etanercept
KW  - skin equivalents
Y1  - 2018
U6  - https://doi.org/10.7150/thno.21668
SN  - 1838-7640
VL  - 8
IS  - 2
SP  - 450
EP  - 463
PB  - Ivyspring International Publisher
CY  - Lake haven
ER  - 
TY  - JOUR
A1  - Gerecke, Christian
A1  - Edlich, Alexander
A1  - Giulbudagian, Michael
A1  - Schumacher, Fabian
A1  - Zhang, Nan
A1  - Said, Andre
A1  - Yealland, Guy
A1  - Lohan, Silke B.
A1  - Neumann, Falko
A1  - Meinke, Martina C.
A1  - Ma, Nan
A1  - Calderon, Marcelo
A1  - Hedtrich, Sarah
A1  - Schaefer-Korting, Monika
A1  - Kleuser, Burkhard
T1  - Biocompatibility and characterization of polyglycerol-based thermoresponsive nanogels designed as novel drug-delivery systems and their intracellular localization in keratinocytes
JF  - Nanotoxicology
N2  - Novel nanogels that possess the capacity to change their physico-chemical properties in response to external stimuli are promising drug-delivery candidates for the treatment of severe skin diseases. As thermoresponsive nanogels (tNGs) are capable of enhancing penetration through biological barriers such as the stratum corneum and are taken up by keratinocytes of human skin, potential adverse consequences of their exposure must be elucidated. In this study, tNGs were synthesized from dendritic polyglycerol (dPG) and two thermoresponsive polymers. tNG_dPG_tPG are the combination of dPG with poly(glycidyl methyl ether-co-ethyl glycidyl ether) (p(GME-co-EGE)) and tNG_dPG_pNIPAM the one with poly(N-isopropylacrylamide) (pNIPAM). Both thermoresponsive nanogels are able to incorporate high amounts of dexamethasone and tacrolimus, drugs used in the treatment of severe skin diseases. Cellular uptake, intracellular localization and the toxicological properties of the tNGs were comprehensively characterized in primary normal human keratinocytes (NHK) and in spontaneously transformed aneuploid immortal keratinocyte cell line from adult human skin (HaCaT). Laser scanning confocal microscopy revealed fluorescently labeled tNGs entered into the cells and localized predominantly within lysosomal compartments. MTT assay, comet assay and carboxy-H2DCFDA assay, demonstrated neither cytotoxic or genotoxic effects, nor any induction of reactive oxygen species of the tNGs in keratinocytes. In addition, both tNGs were devoid of eye irritation potential as shown by bovine corneal opacity and permeability (BCOP) test and red blood cell (RBC) hemolysis assay. Therefore, our study provides evidence that tNGs are locally well tolerated and underlines their potential for cutaneous drug delivery.
KW  - Drug delivery
KW  - nanoparticles
KW  - particle characterization
KW  - keratinocytes
KW  - nanotoxicology
Y1  - 2017
U6  - https://doi.org/10.1080/17435390.2017.1292371
SN  - 1743-5390
SN  - 1743-5404
VL  - 11
SP  - 267
EP  - 277
PB  - Routledge, Taylor & Francis Group
CY  - Abingdon
ER  - 
TY  - JOUR
A1  - Dwi Putra, Sulistyo Emantoko
A1  - Reichetzeder, Christoph
A1  - Hasan, Ahmed Abdallah Abdalrahman Mohamed
A1  - Slowinski, Torsten
A1  - Chu, Chang
A1  - Krämer, Bernhard K.
A1  - Kleuser, Burkhard
A1  - Hocher, Berthold
T1  - Being born large for gestational age is associated with increased global placental DNA methylation
JF  - Scientific Reports
N2  - Being born small (SGA) or large for gestational age (LGA) is associated with adverse birth outcomes and metabolic diseases in later life of the offspring. It is known that aberrations in growth during gestation are related to altered placental function. Placental function is regulated by epigenetic mechanisms such as DNA methylation. Several studies in recent years have demonstrated associations between altered patterns of DNA methylation and adverse birth outcomes. However, larger studies that reliably investigated global DNA methylation are lacking. The aim of this study was to characterize global placental DNA methylation in relationship to size for gestational age. Global DNA methylation was assessed in 1023 placental samples by LC-MS/MS. LGA offspring displayed significantly higher global placental DNA methylation compared to appropriate for gestational age (AGA; p<0.001). ANCOVA analyses adjusted for known factors impacting on DNA methylation demonstrated an independent association between placental global DNA methylation and LGA births (p<0.001). Tertile stratification according to global placental DNA methylation levels revealed a significantly higher frequency of LGA births in the third tertile. Furthermore, a multiple logistic regression analysis corrected for known factors influencing birth weight highlighted an independent positive association between global placental DNA methylation and the frequency of LGA births (p=0.001).
KW  - fetal origins hypothesis
KW  - birth weight
KW  - repetitive elements
KW  - glucocorticoid receptor
KW  - nutrient transport
KW  - growth restriction
KW  - later health
KW  - pregnancy
KW  - genes
KW  - patterns
Y1  - 2020
U6  - https://doi.org/10.1038/s41598-020-57725-0
SN  - 2045-2322
VL  - 10
IS  - 1
SP  - 1
EP  - 10
PB  - Springer Nature
CY  - London
ER  - 
TY  - JOUR
A1  - Fink, Julian
A1  - Schumacher, Fabian
A1  - Schlegel, Jan
A1  - Stenzel, Philipp
A1  - Wigger, Dominik
A1  - Sauer, Markus
A1  - Kleuser, Burkhard
A1  - Seibel, Jürgen
T1  - Azidosphinganine enables metabolic labeling and detection of sphingolipid de novo synthesis
JF  - Organic & biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry
N2  - Here were report the combination of biocompatible click chemistry of omega-azidosphinganine with fluorescence microscopy and mass spectrometry as a powerful tool to elaborate the sphingolipid metabolism. The azide probe was efficiently synthesized over 13 steps starting from l-serine in an overall yield of 20% and was used for live-cell fluorescence imaging of the endoplasmic reticulum in living cells by bioorthogonal click reaction with a DBCO-labeled fluorophore revealing that the incorporated analogue is mainly localized in the endoplasmic membrane like the endogenous species. A LC-MS(/MS)-based microsomal in vitro assay confirmed that omega-azidosphinganine mimics the natural species enabling the identification and analysis of metabolic breakdown products of sphinganine as a key starting intermediate in the complex sphingolipid biosynthetic pathways. Furthermore, the sphinganine-fluorophore conjugate after click reaction was enzymatically tolerated to form its dihydroceramide and ceramide metabolites. Thus, omega-azidosphinganine represents a useful biofunctional tool for metabolic investigations both by in vivo fluorescence imaging of the sphingolipid subcellular localization in the ER and by in vitro high-resolution mass spectrometry analysis. This should reveal novel insights of the molecular mechanisms sphingolipids and their processing enzymes have e.g. in infection.
Y1  - 2021
U6  - https://doi.org/10.1039/d0ob02592e
SN  - 1477-0520
SN  - 1477-0539
VL  - 19
IS  - 10
SP  - 2203
EP  - 2212
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Müller, S. M.
A1  - Finke, Hannah
A1  - Ebert, Franziska
A1  - Kopp, Johannes Florian
A1  - Schumacher, Fabian
A1  - Kleuser, Burkhard
A1  - Francesconi, Kevin A.
A1  - Raber, G.
A1  - Schwerdtle, Tanja
T1  - Arsenic-containing hydrocarbons
BT  - effects on gene expression, epigenetics, and biotransformation in HepG2 cells
JF  - Archives of toxicology : official journal of EUROTOX
N2  - Arsenic-containing hydrocarbons (AsHCs), a subgroup of arsenolipids found in fish and algae, elicit substantial toxic effects in various human cell lines and have a considerable impact on cellular energy levels. The underlying mode of action, however, is still unknown. The present study analyzes the effects of two AsHCs (AsHC 332 and AsHC 360) on the expression of 44 genes covering DNA repair, stress response, cell death, autophagy, and epigenetics via RT-qPCR in human liver (HepG2) cells. Both AsHCs affected the gene expression, but to different extents. After treatment with AsHC 360, flap structure-specific endonuclease 1 (FEN1) as well as xeroderma pigmentosum group A complementing protein (XPA) and (cytosine-5)-methyltransferase 3A (DNMT3A) showed time- and concentration-dependent alterations in gene expression, thereby indicating an impact on genomic stability. In the subsequent analysis of epigenetic markers, within 72 h, neither AsHC 332 nor AsHC 360 showed an impact on the global DNA methylation level, whereas incubation with AsHC 360 increased the global DNA hydroxymethylation level. Analysis of cell extracts and cell media by HPLC-mass spectrometry revealed that both AsHCs were considerably biotransformed. The identified metabolites include not only the respective thioxo-analogs of the two AsHCs, but also several arsenic-containing fatty acids and fatty alcohols, contributing to our knowledge of biotransformation mechanisms of arsenolipids.
KW  - Arsenolipids
KW  - Gene expression
KW  - Arsenic-containing hydrocarbons
KW  - Global DNA methylation
KW  - Arsenic speciation
KW  - Metabolism
Y1  - 2018
U6  - https://doi.org/10.1007/s00204-018-2194-z
SN  - 0340-5761
SN  - 1432-0738
VL  - 92
IS  - 5
SP  - 1751
EP  - 1765
PB  - Springer
CY  - Heidelberg
ER  -