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The Functional and Structural Analysis of a Mimetic Peptide of Human Hepatic Lipase
Author(s) -
Coady Breanne,
Courage Emily,
Fitzpatrick Madeline,
Hickey Kala,
Booth Valerie,
Brown Robert
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.890.16
Subject(s) - peptide , chemistry , biochemistry , hepatic lipase , cholesterol , circular dichroism , lipoprotein
Human hepatic lipase (HL) hydrolyzes triglycerides and phospholipids within circulating lipoproteins. HL is bound to heparan sulfate proteoglycans (HPSG) and is believed to function as a head to tail homodimer. The hydrolysis of lipids within high‐density lipoproteins (HDL) liberates preβ 1 ‐HDL that can accept extrahepatic cholesterol during the anti‐atherogenic process of reverse cholesterol transport. Displacing HL from HSPG to the bloodstream allows HL to access more HDL, ultimately generating more preβ 1 ‐HDL. We hypothesized that a peptide mimicking the major heparin binding domain (HBD) of HL would displace HL from HSPG. To test this hypothesis, we used a fusion protein with a cleavable peptide containing the major HBD of HL. The fusion protein retained the heparin binding properties of human HL, which suggests that the HL‐HSPG association may not require a homodimer structure. Using HEK293 cells expressing HL, we showed that the fusion protein displaces HL from the cell surface at 4°C. We also sought to determine structural properties of the cleaved peptide. Circular dichroism studies showed the mimetic peptide had a propensity to become α‐helical in the presence of trifluoroethanol. Proton nuclear magnetic resonance experiments further show that the peptide undergoes a structural change in the presence of heparin. Overall, we have generated a functional peptide that mimics the HBD properties of HL and it can displace cell surface HL. We anticipate testing whether it can ultimately increase the generation of preβ 1 ‐HDL and improve cholesterol efflux. Funded by the Canadian Institutes of Health Research (#RNL‐125110), and the Research & Development Corporation of Newfoundland and Labrador (#5404.1358.102).