@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{SchellChudobaLeboucheretal.2020, author = {Schell, Mareike and Chudoba, Chantal and Leboucher, Antoine and Alfine, Eugenia and Flore, Tanina and Ritter, Katrin and Weiper, Katharina and Wernitz, Andreas and Henkel, Janin and Kleinridders, Andr{\´e}}, title = {Interplay of Dietary Fatty Acids and Cholesterol Impacts Brain Mitochondria and Insulin Action}, series = {Nutrients}, volume = {12}, journal = {Nutrients}, number = {5}, publisher = {MDPI}, address = {Basel}, issn = {2072-6643}, doi = {10.3390/nu12051518}, pages = {22}, year = {2020}, abstract = {Overconsumption of high-fat and cholesterol-containing diets is detrimental for metabolism and mitochondrial function, causes inflammatory responses and impairs insulin action in peripheral tissues. Dietary fatty acids can enter the brain to mediate the nutritional status, but also to influence neuronal homeostasis. Yet, it is unclear whether cholesterol-containing high-fat diets (HFDs) with different combinations of fatty acids exert metabolic stress and impact mitochondrial function in the brain. To investigate whether cholesterol in combination with different fatty acids impacts neuronal metabolism and mitochondrial function, C57BL/6J mice received different cholesterol-containing diets with either high concentrations of long-chain saturated fatty acids or soybean oil-derived poly-unsaturated fatty acids. In addition, CLU183 neurons were stimulated with combinations of palmitate, linoleic acid and cholesterol to assess their effects on metabolic stress, mitochondrial function and insulin action. The dietary interventions resulted in a molecular signature of metabolic stress in the hypothalamus with decreased expression of occludin and subunits of mitochondrial electron chain complexes, elevated protein carbonylation, as well as c-Jun N-terminal kinase (JNK) activation. Palmitate caused mitochondrial dysfunction, oxidative stress, insulin and insulin-like growth factor-1 (IGF-1) resistance, while cholesterol and linoleic acid did not cause functional alterations. Finally, we defined insulin receptor as a novel negative regulator of metabolically stress-induced JNK activation.}, language = {en} }