Ilka Verena Stocker,a, Steven Ray Wilsona,b, Hanne Røberg-Larsena,b
a Section of Chemical Life Science, Department of Chemistry, University of Oslo, Norway
b Hybrid Technology Hub, Faculty of Medicine, University of Oslo, Norway
Email: i.v.stocker@kjemi.uio.no
Organoids, which are laboratory grown models of organs, can potentially be used to model and mimic organ- and disease development. Organoids can be grown from e.g. induced pluripotent stem cells or from adult stem cells and can be differentiated into different types of specialized cells, for example pancreatic islets.[1]
Pancreatic proteins such as insulin and glucagon are secreted from pancreatic islets, but also chemokines, such as MCP-1 (Monocyte Chemoattractant Protein-1) can be secreted. Insulin and glucagon are crucial hormones in glucose homeostasis, while MCP-1 is a small signal protein which is involved in inflammatory processes and has been linked to diabetic complications. Determining small intact, low abundant proteins in biological samples by liquid chromatography and mass spectrometry is challenging [1]. A key issue is interferences from other proteins such as bovine serum albumin (BSA), which is abundantly present in biological samples and also in cell medium. Hence, separation of BSA from all analytes of interest is necessary [2]. However, we have seen that the presence of BSA in samples also can be beneficial, as non-specific adsorption of low-abundant proteins could be reduced in the presence of BSA. Here, we describe method optimizations for various small proteins in islet organoid secretions, considering both the pro´s and cons of BSA presence [3].
References
1 Olsen, C., Wang, C., Abadpour, S., Lundanes, E., Hansen, A.S., Skottvoll, F.S., Scholz, H., Wilson, S.R.,
Determination of insulin secretion from stem cell-derived islet organoids with liquid chromatography-tandem mass spectrometry, Journal of Chromatography B, Volume 1215, 2023, 123577, ISSN 1570-0232,
https://doi.org/10.1016/j.jchromb.2022.123577.
2 Hrušková, H., Olsen, C., Řemínek, R., Wang, C., Aizenshtadt, A., Krauss, S., Scholz, H., Røberg-Larsen, H., Foret, F., Wilson, S.R., Preparative agarose gel electrophoresis for reducing matrix interferences of organoid cell medium prior to LC-MS analysis of insulin, Journal of Chromatography A, Volume 1717, 2024, 464669, ISSN 0021-9673, https://doi.org/10.1016/j.chroma.2024.464669.
3 Hrušková, H., Johnsen, M.T.S.G., Stocker, I. et.al., manuscript in preparation.