@article{FeddersMuenznerWeberetal.2021,
  author    = {Fedders, Ronja and Muenzner, Matthias and Weber, Pamela and Sommerfeld, Manuela and Knauer, Miriam and Kedziora, Sarah and Kast, Naomi and Heidenreich, Steffi and Raila, Jens and Weger, Stefan and Henze, Andrea and Schupp, Michael},
  title     = {Liver-secreted RBP4 does not impair glucose homeostasis in mice},
  series = {The journal of biological chemistry},
  volume    = {293},
  journal   = {The journal of biological chemistry},
  number    = {39},
  publisher = {American Society for Biochemistry and Molecular Biology},
  address   = {Bethesda},
  issn      = {1083-351X},
  doi       = {10.1074/jbc.RA118.004294},
  pages     = {15269 -- 15276},
  year      = {2021},
  abstract  = {Retinol-binding protein 4 (RBP4) is the major transport protein for retinol in blood. Recent evidence from genetic mouse models shows that circulating RBP4 derives exclusively from hepatocytes. Because RBP4 is elevated in obesity and associates with the development of glucose intolerance and insulin resistance, we tested whether a liver-specific overexpression of RBP4 in mice impairs glucose homeostasis. We used adeno-associated viruses (AAV) that contain a highly liver-specific promoter to drive expression of murine RBP4 in livers of adult mice. The resulting increase in serum RBP4 levels in these mice was comparable with elevated levels that were reported in obesity. Surprisingly, we found that increasing circulating RBP4 had no effect on glucose homeostasis. Also during a high-fat diet challenge, elevated levels of RBP4 in the circulation failed to aggravate the worsening of systemic parameters of glucose and energy homeostasis. These findings show that liver-secreted RBP4 does not impair glucose homeostasis. We conclude that a modest increase of its circulating levels in mice, as observed in the obese, insulin-resistant state, is unlikely to be a causative factor for impaired glucose homeostasis.},
  language  = {en}
}
@article{HenzeRailaScholzeetal.2013,
  author    = {Henze, Andrea and Raila, Jens and Scholze, Alexandra and Zidek, Walter and Tepel, Martin and Schweigert, Florian J.},
  title     = {Does N-Acetylcysteine modulate post-translational modifications of transthyretin in hemodialysis patients?},
  series = {Antioxidants \& redox signaling},
  volume    = {19},
  journal   = {Antioxidants \& redox signaling},
  number    = {11},
  publisher = {Liebert},
  address   = {New Rochelle},
  issn      = {1523-0864},
  doi       = {10.1089/ars.2012.5125},
  pages     = {1166 -- 1172},
  year      = {2013},
  abstract  = {It is assumed that effects of the thiol antioxidant N-acetylcysteine (NAC) are mediated by interaction with protein-associated cysteine residues, however, information on protein level in vivo are missing. Therefore, we analyzed NAC-induced modifications of the protein transthyretin (TTR) in plasma of hemodialysis patients in a randomized, placebo-controlled study. TTR was selected due to its low molecular weight and the free cysteine residue in the polypeptide chain, which is known to be extensively modified by formation of mixed disulfides. The intravenous application of NAC during a hemodialysis session resulted in a substantial increase of native TTR from median 15\% (range 8.8\%-30\%) to median 40\% (37-50) and reduction of S-cysteinylated TTR [51\% (44-60) vs. 6.6\% (2.4-10)]. Additionally the pronounced formation of a TTR-NAC adduct was detected. However, all these modifications seemed to be reversible. Additionally, in vitro incubation of plasma with NAC confirmed the in vivo results and indicated that changes in post-translational modification pattern of TTR were a function of NAC concentration. Based on these observations and the essential metabolic and biochemical role of protein-associated cysteine residues we hypothesize that the interaction of NAC with proteins may explain altered protein functions due to modification of cysteine residues. Antioxid. Redox Signal. 19, 1166-1172.},
  language  = {en}
}