Monoclonal antibodies that bind to the Ly6 domain of GPIHBP1 abolish the binding of LPL

Xuchen Hu, Mark W. Sleeman, Kazuya Miyashita, MacRae F. Linton, Christopher M. Allan, Cuiwen He, Mikael Larsson, Yiping Tu, Norma P. Sandoval, Rachel S. Jung, Alaleh Mapar, Tetsuo Machida, Masami Murakami, Katsuyuki Nakajima, Michael Ploug, Loren G. Fong, Stephen G. Young, Anne P Beigneux

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Abstract

GPIHBP1, an endothelial cell protein, binds LPL in the interstitial spaces and shuttles it to its site of action inside blood vessels. For years, studies of human GPIHBP1 have been hampered by an absence of useful antibodies. We reasoned that monoclonal antibodies (mAbs) against human GPIHBP1 would be useful for 1) defining the functional relevance of GPIHBP1's Ly6 and acidic domains to the binding of LPL; 2) ascertaining whether human GPIHBP1 is expressed exclusively in capillary endothelial cells; and 3) testing whether GPIHBP1 is detectable in human plasma. Here, we report the development of a panel of human GPIHBP1-specific mAbs. Two mAbs against GPIHBP1's Ly6 domain, RE3 and RG3, abolished LPL binding, whereas an antibody against the acidic domain, RF4, did not. Also, mAbs RE3 and RG3 bound with reduced affinity to a mutant GPIHBP1 containing an Ly6 domain mutation (W109S) that abolishes LPL binding. Immunohistochemistry studies with the GPIHBP1 mAbs revealed that human GPIHBP1 is expressed only in capillary endothelial cells. Finally, we created an ELISA that detects GPIHBP1 in human plasma. That ELISA should make it possible for clinical lipidologists to determine whether plasma GPIHBP1 levels are a useful biomarker of metabolic or vascular disease.-Hu, X., M. W. Sleeman, K. Miyashita, M. F. Linton, C. M. Allan, C. He, M. Larsson, Y. Tu, N. P. Sandoval, R. S. Jung, A. Mapar, T. Machida, M. Murakami, K. Nakajima, M. Ploug, L. G. Fong, S. G. Young, and A. P. Beigneux. Monoclonal antibodies that bind to the Ly6 domain of GPIHBP1 abolish the binding of LPL.

Original languageEnglish
Pages (from-to)208-215
Number of pages8
JournalJournal of Lipid Research
Volume58
Issue number1
DOIs
Publication statusPublished - 1 Jan 2017

Keywords

  • Chylomicrons
  • dyslipidemias
  • endothelial cells
  • lipoprotein lipase
  • Triglycerides

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