HDL and CER-001 Inverse-Dose Dependent Inhibition of Atherosclerotic Plaque Formation in apoE-/- Mice: Evidence of ABCA1 Down-Regulation.
OBJECTIVE
CER-001 is a novel engineered HDL-mimetic comprised of recombinant human apoA-I and charged phospholipids that was designed to mimic the beneficial properties of nascent pre-ß HDL. In this study, we have evaluated the dose-dependent regulation of ABCA1 expression in vitro and in vivo in the presence of CER-001 and native HDL (HDL3).


RESULTS
CER-001 induced cholesterol efflux from J774 macrophages in a dose-dependent manner similar to natural HDL. A strong down-regulation of the ATP-binding cassette A1 (ABCA1) transporter mRNA (- 50%) as well as the ABCA1 membrane protein expression (- 50%) was observed at higher doses of CER-001 and HDL3 compared to non-lipidated apoA-I. In vivo, in an apoE-/- mouse "flow cessation model," in which the left carotid artery was ligatured to induce local inflammation, the inhibition of atherosclerotic plaque burden progression in response to a dose-range of every-other-day CER-001 or HDL in the presence of a high-fat diet for two weeks was assessed. We observed a U-shaped dose-response curve: inhibition of the plaque total cholesterol content increased with increasing doses of CER-001 or HDL3 up to a maximum inhibition (- 51%) at 5 mg/kg; however, as the dose was increased above this threshold, a progressively less pronounced inhibition of progression was observed, reaching a complete absence of inhibition of progression at doses of 20 mg/kg and over. ABCA1 protein expression in the same atherosclerotic plaque was decreased by-45% and-68% at 50 mg/kg for CER-001 and HDL respectively. Conversely, a-12% and 0% decrease in ABCA1 protein expression was observed at the 5 mg/kg dose for CER-001 and HDL respectively.


CONCLUSIONS
These data demonstrate that high doses of HDL and CER-001 are less effective at slowing progression of atherosclerotic plaque in apoE-/- mice compared to lower doses, following a U-shaped dose-response curve. A potential mechanism for this phenomenon is supported by the observation that high doses of HDL and CER-001 induce a rapid and strong down-regulation of ABCA1 both in vitro and in vivo. In conclusion, maximally efficient HDL- or CER-001-mediated cholesterol removal from atherosclerotic plaque is achieved by maximizing macrophage-mediated efflux from the plaque while minimizing dose-dependent down-regulation of ABCA1 expression. These observations may help define the optimal dose of HDL mimetics for testing in clinical trials of atherosclerotic burden regression.
Cerenis Therapeutics SA, Labege, France.
Claudine
C
Tardy
Cerenis Therapeutics SA, Labege, France.
Marine
M
Goffinet
Cerenis Therapeutics SA, Labege, France.
Nadia
N
Boubekeur
Cerenis Therapeutics SA, Labege, France.
Guy
G
Cholez
Cerenis Therapeutics Inc., Ann Arbor, Michigan, United States of America.
Rose
R
Ackermann
Cerenis Therapeutics Inc., Ann Arbor, Michigan, United States of America.
Gavin
G
Sy
Cerenis Therapeutics SA, Labege, France.
Constance
C
Keyserling
Cerenis Therapeutics Inc., Ann Arbor, Michigan, United States of America.
Narendra
N
Lalwani
Cerenis Therapeutics SA, Labege, France.
John F
JF
Paolini
Cerenis Therapeutics SA, Labege, France.
Jean-Louis
JL
Dasseux
Cerenis Therapeutics SA, Labege, France.
Ronald
R
Barbaras
Cerenis Therapeutics SA, Labege, France.
Rudi
R
Baron
D064286:ATP Binding Cassette Transporter 1 / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D016632:Apolipoprotein A-I / Q000494:pharmacology*; D001057:Apolipoproteins E / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects*; D008075:Lipoproteins, HDL / Q000494:pharmacology*; D051379:Mice; D010743:Phospholipids / Q000494:pharmacology*; D058226:Plaque, Atherosclerotic / Q000235:genetics / Q000378:metabolism / Q000517:prevention & control*; D011994:Recombinant Proteins / Q000494:pharmacology*
D064286:ATP Binding Cassette Transporter 1; D016632:Apolipoprotein A-I; D001057:Apolipoproteins E; C000591544:CER-001; D008075:Lipoproteins, HDL; D010743:Phospholipids; D011994:Recombinant Proteins