Our research focus on structural and functional aspects of proteins involved in disease relevant pathways. The ultimate goal of these studies is to elucidate the function of these proteins in vitro and in vivo and to facilitate the translation of these findings into a clinical setting, particularly within the field of oncology and lipid metabolism.
We focus on biochemical and biophysical characterization of disease relevant proteins and their interacting ligands with special emphasis on cancer dissemination and dyslipidemia. We provide detailed understanding on how a given pathway maintains homeostasis in normal physiology and why certain aberrations—such a missense mutations and natural polymorphisms—cause dysregulation in pathophysiology. Ultimately, we seek to use this information in translational pipelines – e.g. our uPAR‐targeting peptide for non‐invasive PET imaging of uPAR‐expression in chronic inflammation and solid cancer.
These discoveries were made by harvesting the full synergy from interactive collaborations.
1: Uncovered a new paradigm in the regulation of intravascular lipid metabolism wherein intrinsic protein disorder in GPIHBP1 secures proper compartmentalization of lipoprotein lipase (LPL) and stabilizes the enzyme against spontaneous inactivation.
- Mysling S, et al. (2016) The acidic domain of the endothelial membrane protein GPIHBP1 stabilizes lipoprotein lipase activity by preventing unfolding of its catalytic domain. Elife 5:e12095
- Kristensen KK, et al. (2018) A disordered acidic domain in GPIHBP1 harboring a sulfated tyrosine regulates lipoprotein lipase. Proceedings of the National Academy of Sciences of the United States of America 115(26):E6020
2: Discovered a new mechanism for LPL regulation by which binding of the endogenous inhibitor ANGPTL4 induces a cooperative allosteric unfolding leading to the irreversible collapse of LPL’s catalytic triad. Binding to GPIHBP1 alleviates this inhibition.
- Mysling S, et al. (2016) The angiopoietin-like protein ANGPTL4 catalyzes unfolding of the hydrolase domain in lipoprotein lipase and the endothelial membrane protein GPIHBP1 counteracts this unfolding. Elife 5:20958
- Kristensen KK, et al. (2020) Unfolding of monomeric lipoprotein lipase by ANGPTL4: Insight into the regulation of plasma triglyceride metabolism. Proceedings of the National Academy of Sciences of the United States of America 117(8):4337–
- Young SG, et al. (2019) GPIHBP1 and Lipoprotein Lipase, Partners in Plasma Triglyceride Metabolism. Cell Metab 30(1):51– 65
3: Solved the first crystal structure of LPL.
- Birrane G, et al. (2019) Structure of the lipoprotein lipase-GPIHBP1 complex that mediates plasma triglyceride hydrolysis. Proceedings of the National Academy of Sciences of the United States of America 116(5):1723–1732
4: Discovered a new etiology for acquired chylomicronemia
- Beigneux AP, et al. (2017) Autoantibodies against GPIHBP1 as a Cause of Hypertriglyceridemia. N Engl J Med 376(17):1647–1658
- Lutz J, et al. (2020) Chylomicronemia from GPIHBP1 autoantibodies successfully treated with rituxumab: A case report. Ann Intern Med. doi:7326/L20-0327
5: Developed a peptide probe for non-invasive imaging of solid cancers lesions.
- Ploug M (2013) Structure-driven design of radionuclide tracers for non-invasive imaging of uPAR anf targeted radiotherapy. The tale of a synthetic peptide antagonsist. Theranostics 3(7):467–476
- Persson M, et al. (2015) First-in-human uPAR PET: Imaging of cancer aggressiveness. Theranostics 5(12):1303–1316
Our current research projects have a dual focus: First, we aim at transforming our uPAR-targeted non-invasive PET imaging platform into an optical imaging modality with a view to fluorescence guided intra-operative imaging with improved margin resection. The Holy Grail of successful cancer surgery is to obtain clear resection margins without the need to perform a radical anatomical excision with substantial loss of vital healthy tissue. Second, we will study the molecular mechanisms responsible for ANGPTL-mediated catalysis of LPL inactivation by unfolding. Ultimately, we will used this information to design a stable LPL variant with a view to enzyme replacement therapy in patients with acute dyslipidemia.
To accomplish our research goals, we perform high-end biophysical analyses with surface plasmon resonance (SPR), microscale thermophoresis (MST), hydrogen-deuterium exchange mass spectrometry (HDX-MS), X-ray crystallography, NMR, small angle X-ray scattering (SAXS), and nano-DSF to delineate essential structure-function relationships using highly purified protein preparations produced in house. We have a particularly robust expression system using Drosophila S2 cell, which produces recombinant proteins with uniform glycosylations and are well suited for production of thermolabile proteins. We have a long experience in determining real-time kinetic rate constants with surface plasmon resonance and have used HDX-MS extensively in collaboration with Dr Thomas J. D. Jørgensen.
Kristensen, K.K., Leth-Espensen, K.Z., Mertens, H.D.T., Birrane, G., Meiyappan, M., Olivecrona, G., Jørgensen, T.J.D., Young, S.G., and Ploug, M. “Unfolding of monomeric lipoprotein lipase by ANGPTL4: Insight into the regulation of plasma triglyceride metabolism”
Proc. Natl. Acad. Sci. 117 (2020) 4337−4346
Young, S.G., Fong, L.G., Beigneux, A., Allan, C.M., He, C., Nakajima, K., Meiyappan, M., Birrane, G., and Ploug, M. “GPIHBP1 and lipoprotein lipase, partners in plasma triglyceride metabolism”
Cell Metabolism 30 (2019) 51−65
Leth, J.M., Mertens, H.D., Leth-Espensen, K.Z., Jørgensen, T.J.D., and Ploug, M. “Did evolution create a flexible ligand-binding cavity in the urokinase receptor through deletion of a plesiotypic disulfide bond?”
J. Biol. Chem. 295 (2019) 7403–7418
Kristensen, K.K., Midtgaard, S.R., Mysling, S., Korov, O., Hansen, L.B., Skar-Gislinge, N., Kragelund, B.K., Olivecrona, G., Young, S.G., Jørgensen, T.J.D., Fong, L.G., and Ploug, M. “A Disordered Acidic Domain in GPIHBP1 haboring a Sulfated Tyrosine regulates Lipoprotein Lipase”
Proc. Natl. Acad. Sci. 115 (2018) E6020-E6029
Mysling, S., Kristensen, K.K., Larsson, M., Beigneux, A.P., Gårdsvoll, H., Fong, L.G., Bensadoun, A., Jørgensen, T.D., Young, S.G., and Ploug, M. “The acidic domain of the endothelial membrane protein GPIHBP1 stabilizes lipoprotein lipase activity by preventing unfolding of its catalytic domain”
eLife (2016) doi: 10.7554/eLife.12095
Mysling, S., Kristensen, K.K., Larsson, M., Korov, O., Bensadoun, A., Jørgensen, T.J.D., Olivecrona, G., Young, S., and Ploug, M. “The angiopoietin-like protein ANGPTL4 catalyzes unfolding of the hydrolase domain in lipoprotein lipase and the endothelial membrane protein GPIHBP1 counteracts this unfolding”
eLife (2016) doi: 10.77554/eLife.20958