1. Lipoprotein lipase reaches the capillary lumen in chickens despite an apparent absence of GPIHBP1
- Author
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Rosemary L. Walzem, André Bensadoun, Yiping Tu, Norma P. Sandoval, Cuiwen He, Loren G. Fong, Mikael Larsson, Richard Kuo, Paul Kim, Stephen G. Young, Anne P. Beigneux, Sandra Duarte-Vogel, Rachel S. Jung, Brian J. Raney, Xuchen Hu, Tara R. Price, Haibo Jiang, and Christopher M. Allan
- Subjects
Male ,0301 basic medicine ,Adipose tissue ,Cardiovascular ,Mice ,chemistry.chemical_compound ,0302 clinical medicine ,Receptors ,Lipoprotein ,Receptor ,Lipoprotein lipase ,biology ,Goats ,digestive, oral, and skin physiology ,GPIHBP1 ,Heart ,General Medicine ,Adipose Tissue ,Low-density lipoprotein ,embryonic structures ,Female ,lipids (amino acids, peptides, and proteins) ,Research Article ,medicine.medical_specialty ,animal structures ,Lipoproteins ,Lumen (anatomy) ,Antibodies ,03 medical and health sciences ,Von Willebrand factor ,Internal medicine ,medicine ,Animals ,Humans ,Triglycerides ,Receptors, Lipoprotein ,Messenger RNA ,Heparin ,Endothelial Cells ,nutritional and metabolic diseases ,Lipid Metabolism ,Capillaries ,Lipoprotein Lipase ,030104 developmental biology ,Endocrinology ,chemistry ,Immunoglobulin G ,biology.protein ,Chickens ,030217 neurology & neurosurgery - Abstract
In mammals, GPIHBP1 is absolutely essential for transporting lipoprotein lipase (LPL) to the lumen of capillaries, where it hydrolyzes the triglycerides in triglyceride-rich lipoproteins. In all lower vertebrate species (e.g., birds, amphibians, reptiles, fish), a gene for LPL can be found easily, but a gene for GPIHBP1 has never been found. The obvious question is whether the LPL in lower vertebrates is able to reach the capillary lumen. Using purified antibodies against chicken LPL, we showed that LPL is present on capillary endothelial cells of chicken heart and adipose tissue, colocalizing with von Willebrand factor. When the antibodies against chicken LPL were injected intravenously into chickens, they bound to LPL on the luminal surface of capillaries in heart and adipose tissue. LPL was released rapidly from chicken hearts with an infusion of heparin, consistent with LPL being located inside blood vessels. Remarkably, chicken LPL bound in a specific fashion to mammalian GPIHBP1. However, we could not identify a gene for GPIHBP1 in the chicken genome, nor could we identify a transcript for GPIHBP1 in a large chicken RNA-seq data set. We conclude that LPL reaches the capillary lumen in chickens - as it does in mammals - despite an apparent absence of GPIHBP1.
- Published
- 2017