@article{WardelmannRathCastroetal.2021, author = {Wardelmann, Kristina and Rath, Michaela and Castro, Jos{\´e} Pedro and Bl{\"u}mel, Sabine and Schell, Mareike and Hauffe, Robert and Schumacher, Fabian and Flore, Tanina and Ritter, Katrin and Wernitz, Andreas and Hosoi, Toru and Ozawa, Koichiro and Kleuser, Burkhard and Weiß, J{\"u}rgen and Sch{\"u}rmann, Annette and Kleinridders, Andr{\´e}}, title = {Central acting Hsp10 regulates mitochondrial function, fatty acid metabolism and insulin sensitivity in the hypothalamus}, series = {Antioxidants}, volume = {10}, journal = {Antioxidants}, number = {5}, publisher = {MDPI}, address = {Basel}, issn = {2076-3921}, doi = {10.3390/antiox10050711}, pages = {22}, year = {2021}, abstract = {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.}, language = {en} } @article{NicolaiWeishauptBaesleretal.2021, author = {Nicolai, Merle Marie and Weishaupt, Ann-Kathrin and Baesler, Jessica and Brinkmann, Vanessa and Wellenberg, Anna and Winkelbeiner, Nicola Lisa and Gremme, Anna and Aschner, Michael and Fritz, Gerhard and Schwerdtle, Tanja and Bornhorst, Julia}, title = {Effects of manganese on genomic integrity in the multicellular model organism Caenorhabditis elegans}, series = {International Journal of Molecular Sciences}, volume = {22}, journal = {International Journal of Molecular Sciences}, number = {20}, publisher = {MDPI}, address = {Basel}, issn = {1422-0067}, doi = {10.3390/ijms222010905}, pages = {16}, year = {2021}, abstract = {Although manganese (Mn) is an essential trace element, overexposure is associated with Mn-induced toxicity and neurological dysfunction. Even though Mn-induced oxidative stress is discussed extensively, neither the underlying mechanisms of the potential consequences of Mn-induced oxidative stress on DNA damage and DNA repair, nor the possibly resulting toxicity are characterized yet. In this study, we use the model organism Caenorhabditis elegans to investigate the mode of action of Mn toxicity, focusing on genomic integrity by means of DNA damage and DNA damage response. Experiments were conducted to analyze Mn bioavailability, lethality, and induction of DNA damage. Different deletion mutant strains were then used to investigate the role of base excision repair (BER) and dePARylation (DNA damage response) proteins in Mn-induced toxicity. The results indicate a dose- and time-dependent uptake of Mn, resulting in increased lethality. Excessive exposure to Mn decreases genomic integrity and activates BER. Altogether, this study characterizes the consequences of Mn exposure on genomic integrity and therefore broadens the molecular understanding of pathways underlying Mn-induced toxicity. Additionally, studying the basal poly(ADP-ribosylation) (PARylation) of worms lacking poly(ADP-ribose) glycohydrolase (PARG) parg-1 or parg-2 (two orthologue of PARG), indicates that parg-1 accounts for most of the glycohydrolase activity in worms.}, language = {en} }