title: Human plasma very low density lipoprotein carries Indian hedgehog.
abstract: Hedgehog is one of the major morphogens and fulfils critical functions in both the development and maintenance of the vasculature. Hedgehog is highly hydrophobic and its diffusion toward target tissues remains only partly understood. In Drosophila, hedgehog transport via lipophorins is relevant for development, but neither the presence nor a function for a mammalian Hedgehog carried by human plasma lipoproteins has been established. We investigated the presence of Hedgehog on lipoprotein particles and determined its importance for maintaining the endothelium. LTQ-Orbitrap XL analysis of defined plasma lipoproteins revealed that Indian Hedgehog (Ihh) is present in the human very low density lipoprotein (VLDL) fraction but not in other plasma lipoprotein fractions (low density lipoprotein (LDL) and high density lipoprotein (HDL)). Using the same approach, neither Sonic Hedgehog nor Desert Hedgehog could be detected in plasma lipoprotein fractions. Most likely, primary white adipocytes are the source of Ihh loading on VLDL as both transcriptome as well as immunofluorescence analysis showed high expression of Ihh in these cells. Additionally, we show that the endothelial compartment is most likely to be affected by the presence of Ihh on VLDL. Indeed, VLDL increased survival of primary endothelial cells, suggesting that Ihh transport by VLDL is important for maintaining the human endothelium. In conclusion, our study shows that VLDL carries Ihh throughout the body in mammals and Hedgehog signaling by human plasma VLDL particles may affect blood vessel pathophysiology. A combination of three state-of-the-art technologies, proteomics, genomics, and confocal microscopy, appeared to be a powerful tool for analyzing plasma lipoprotein-associated proteins.
authors.affiliation: Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Karla C S
authors.initials: KC
authors.lastname: Queiroz
authors.forename: Rene A
authors.initials: RA
authors.lastname: Tio
authors.forename: Clark J
authors.initials: CJ
authors.lastname: Zeebregts
authors.forename: Maarten F
authors.initials: MF
authors.lastname: Bijlsma
authors.forename: Felix
authors.initials: F
authors.lastname: Zijlstra
authors.forename: Bahram
authors.initials: B
authors.lastname: Badlou
authors.forename: Marcel
authors.initials: M
authors.lastname: de Vries
authors.forename: Carmen V
authors.initials: CV
authors.lastname: Ferreira
authors.forename: C Arnold
authors.initials: CA
authors.lastname: Spek
authors.forename: Maikel P
authors.initials: MP
authors.lastname: Peppelenbosch
authors.forename: Farhad
authors.initials: F
authors.lastname: Rezaee
mesh_terms: D017667:Adipocytes; D053823:Hedgehog Proteins / Q000378:metabolism*; D006801:Humans; D008074:Lipoproteins; D008079:Lipoproteins, VLDL / Q000097:blood / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport
chemical_list: D053823:Hedgehog Proteins; D008074:Lipoproteins; D008079:Lipoproteins, VLDL; C032830:lipophorin