@article{DeutschmannRoggenbuckSchieracketal.2020,
  author    = {Deutschmann, Claudia and Roggenbuck, Dirk and Schierack, Peter and R{\"o}diger, Stefan},
  title     = {Autoantibody testing by enzyme-linked immunosorbent assay-a case in which the solid phase decides on success and failure},
  series = {Heliyon},
  volume    = {6},
  journal   = {Heliyon},
  number    = {1},
  publisher = {Elsevier},
  address   = {London [u.a.]},
  issn      = {2405-8440},
  doi       = {10.1016/j.heliyon.2020.e03270},
  pages     = {6},
  year      = {2020},
  abstract  = {Background: The enzyme-linked immunosorbent assay (ELISA) is an indispensable tool for clinical diagnostics to identify or differentiate diseases such as autoimmune illnesses, but also to monitor their progression or control the efficacy of drugs. One use case of ELISA is to differentiate between different states (e.g. healthy vs. diseased). Another goal is to quantitatively assess the biomarker in question, like autoantibodies. Thus, the ELISA technology is used for the discovery and verification of new autoantibodies, too. Of key interest, however, is the development of immunoassays for the sensitive and specific detection of such biomarkers at early disease stages. Therefore, users have to deal with many parameters, such as buffer systems or antigen-autoantibody interactions, to successfully establish an ELISA. Often, fine-tuning like testing of several blocking substances is performed to yield high signal-to-noise ratios. <br /> Methods: We developed an ELISA to detect IgA and IgG autoantibodies against chitinase-3-like protein 1 (CHI3L1), a newly identified autoantigen in inflammatory bowel disease (IBD), in the serum of control and disease groups (n = 23, respectively). Microwell plates with different surface modifications (PolySorp and MaxiSorp coating) were tested to detect reproducibility problems. <br /> Results: We found a significant impact of the surface properties of the microwell plates. IgA antibody reactivity was significantly lower, since it was in the range of background noise, when measured on MaxiSorp coated plates (p < 0.0001). The IgG antibody reactivity did not differ on the diverse plates, but the plate surface had a significant influence on the test result (p = 0.0005). <br /> Conclusion: With this report, we want to draw readers' attention to the properties of solid phases and their effects on the detection of autoantibodies by ELISA. We want to sensitize the reader to the fact that the choice of the wrong plate can lead to a false negative test result, which in turn has serious consequences for the discovery of autoantibodies.},
  language  = {en}
}
@article{MuenznerTuviaDeutschmannetal.2013,
  author    = {M{\"u}nzner, Matthias and Tuvia, Neta and Deutschmann, Claudia and Witte, Nicole and Tolkachov, Alexander and Valai, Atijeh and Henze, Andrea and Sander, Leif E. and Raila, Jens and Schupp, Michael},
  title     = {Retinol-binding protein 4 and its membrane receptor STRA6 control adipogenesis by regulating cellular retinoid homeostasis and retinoic acid receptor alpha activity},
  series = {Molecular and cellular biology},
  volume    = {33},
  journal   = {Molecular and cellular biology},
  number    = {20},
  publisher = {American Society for Microbiology},
  address   = {Washington},
  issn      = {0270-7306},
  doi       = {10.1128/MCB.00221-13},
  pages     = {4068 -- 4082},
  year      = {2013},
  abstract  = {Retinoids are vitamin A (retinol) derivatives and complex regulators of adipogenesis by activating specific nuclear receptors, including the retinoic acid receptor (RAR) and retinoid X receptor (RXR). Circulating retinol-binding protein 4 (RBP4) and its membrane receptor STRA6 coordinate cellular retinol uptake. It is unknown whether retinol levels and the activity of RAR and RXR in adipocyte precursors are linked via RBP4/STRA6. Here, we show that STRA6 is expressed in precursor cells and, dictated by the apo-and holo-RBP4 isoforms, mediates bidirectional retinol transport that controls RAR alpha activity and subsequent adipocyte differentiation. Mobilization of retinoid stores in mice by inducing RBP4 secretion from the liver activated RAR alpha signaling in the precursor cell containing the stromal-vascular fraction of adipose tissue. Retinol-loaded holo-RBP4 blocked adipocyte differentiation of cultured precursors by activating RAR alpha. Remarkably, retinol-free apo-RBP4 triggered retinol efflux that reduced cellular retinoids, RAR alpha activity, and target gene expression and enhanced adipogenesis synergistically with ectopic STRA6. Thus, STRA6 in adipocyte precursor cells links nuclear RAR alpha activity to the circulating RBP4 isoforms, whose ratio in obese mice was shifted toward limiting the adipogenic potential of their precursors. This novel cross talk identifies a retinoldependent metabolic function of RBP4 that may have important implications for the treatment of obesity.},
  language  = {en}
}