PCSK9, the short track road from discovery as drug target towards the clinic Professor Gilles Lambert, PhD Laboratoire Inserm U1188 Université de la Réunion Faculté de Médecine Saint Denis de la Réunion, France.
Faculty Disclosure Declarat aration ion of non-fina financia cial l interests ests • Affiliation: Uni niver ersité sité de la Réunion nion and nd IN INSERM ERM • Position : Pro rofess essor or of Biochemis emistry y and Cell Biolog ogy • Member of: The he Eu Euro ropea ean n Ath theroscl rosclerosis osis Societ ety y
Faculty Disclosure Declarati ration on of fin financi cial al in intere rests sts For the the la last t 3 years and the the subse bsequent quent 12 month ths: : I I have recei ceived ed resear search ch grants ts A From Sanofi-Regeneron, Amgen, and Pfizer Inc. YES B From the Agence Nationale de la Recherche YES II II I have been en a speaker r or particip cipant ant in accredit redited ed CME/ E/CP CPD A From Sanofi-Regeneron, Amgen, and Pfizer Inc. YES B From PACE YES III III I have been en a cons nsulta tant/st nt/stra rategic egic adviso sor A For Sanofi-Regeneron, Amgen, and Pfizer Inc. YES B For PCSK9 Forum YES IV IV I am a holder lder of (a) patent/share ent/shares/st s/stock ck own wnersh ships ps A Related to presentation NO B Not related to presentation NO
DISCOVERY OF PCSK9
The LDL Receptor 5
Two French Families With Autosomal Dominant Hypercholesterolemia Abifadel et al. (2003) Nature Genetics
PCSK9: gain of function mutations S127R F216L D374Y LDL-C D H N S SP pro-domain catalytic domain C-terminal domain Lambert G et al. (2009) Atherosclerosis
PCSK9 Expression Increases Circulating LDL Cholesterol Levels in Mice * 200 Maxwell and Breslow (2004) Proc Natl Acad Sci USA Plasma Total Cholesterol (mg/dL) Benjannet et al. (2004) J Biol Chem Ad-Null Ad-PCSK9 Park et al. (2004) J Biol Chem Lalanne et al. (2005) J Lipid Res * * 150 100 50 0 0 4 5 7 9 * p<0,05 vs. Ad-null Days post adenoviral infusion
PCSK9: loss of function mutations D H N S SP pro-domain catalytic domain C-terminal domain LDL-C R46L Y142X C679X Lambert G et al. (2009) Atherosclerosis
Cardiovascular benefits of PCSK9 loss of function mutations No Nonsense Mutation 88% reduction in the risk of CHD 50 th Percentile (N=3278) 30 12 20 Coronary Heart Disease (%) 10 8 Prospective study of plasma Frequency (%) 0 LDL-C levels and incidence 0 50 100 150 200 250 300 of CHD according to the PCSK9 142x or PCSK9 679X presence or absence of a PCSK0 142X or PCSK9 679X (N=85) 30 allele (N=3278) taken from 4 a longitudinal, biracial 20 cohort study designed to assess subclinical and clinical atherosclerosis 10 (N=15792) 0 0 No Yes 0 50 100 150 200 250 300 PCSK9 142x or PCSK9 679X Plasma LDL-C in Black Subjects (mg/dL) Cohen J, et al. (2006) N Engl J Med 2006
PCSK9 Knockout Mice Have Decreased Plasma Cholesterol 125 12 Total Cholesterol (mg/dL) 100 10 75 75 * 50 50 25 25 0 Control PCSK9-KO (-/-) * p<0,05 vs. Control Rashid et al. (2005) Proc Natl Acad Sci USA
BIOLOGY OF PCSK9
PCSK9: the enzyme (proprotein convertase) Endoplasmic Reticulum D H N S pro-domain C-terminal domain catalytic domain Golgi D H N S catalytic domain C-terminal domain pro-domain Secretion Lambert G et al. (2009) Atherosclerosis
PCSK9: the chaperone (binds to the LDLR) PCSK9 LDLR Catalytic domain EGFA domain CHRD Pro-domain Endocytosis Seidah NG, et al. (2014) Circ Res
PCSK9 targets the LDLR to the lysosome for degradation LDLR Endosome Merge PCSK9-LDLR Binding Kd= 750 ± 80 nM (at pH 7.5) Kd= 10 ± 1 nM (at pH 5.5) + PCSK9 LDLR Conformation Open (at pH 7.5) Closed (at pH 5.5) alone Open (at pH 5.5) bound to PCSK9 Lambert G et al. (2016) Eur. Heart J. Surdo PL et al. (2011) EMBO Rep
PCSK9 reduces LDLR cell surface expression dose dependently Lambert G. et al. (2014) J Am Coll Cardiol MFI = median fluorescence intensity Thedrez A. et al. (2016) Arterioscler Thromb Vasc Bio * p<0.05, ** p<0.01 vs. condition no PCSK9 (0)
PCSK9 in brief: a natural inhibitor of the LDL receptor Lambert G et al. (2012) J Lipid Res
Statins coregulate the Expression of the LDLR and of PCSK9 0.5% FCS + 20% FCS 0.5% FCS Mevastatin 400 /mL) Statins 9 (ng/m 365 352 345 350 SK9 SREBP2 328 n PCSK 300 Mean PCSK9 LDLR 250 Atorva 10 Atorva 10 Atorva Atorva 20 20 Atorva 40 Atorva 40 Atorva Atorva 80 80 LDL-C (n= (n=449) 449) (n= (n=449) 449) (n=447) (n= 447) (n= (n=399) 399)
The development of PCSK9 inhibitors mAb Lambert G et al. (2012) J Lipid Res
PCSK9 inhibition with mAbs in clinical trials reduces LDLC by 60% on top of standard therapy Alirocumab Evolocumab Robinson JG et al. N Engl J Med 2015;372:1489-1499 Sabatine MS et al. N Engl J Med 2015;372:1500-1509
PCSK9 inhibitors also reduce Lp(a) Non-diabetics Statins Pcsk9 mAbs Diabetics p=0.003 Lipoprotein (a) levels (mg/dl) 50 PCSK9 LDLR * p=0.10 40 p=0.70 p=0.005 # p=0.03 # * # 30 LDL-C -60% 20 = 10 -30% Lp(a) 0 All patients Atorva 10 Atorva 20 Atorva 40 Atorva 80
Lp(a) hepatic clearance is not mediated by the LDLR + PCSK9 (0 - 3.1 ug/mL) LDLR expression PRIMAR MARY HUMAN AN +/- alirocumab (8ug/mL) Fluo. LDL and Lp(a) uptake HEPATOCY OCYTES TES
PCSK9 increases the hepatic secretion of Lp(a) Apo(a) 3-40 40 IV IV IV IV IV IV IV IV IV IV IV N V S1 S1 C 1 2 3 4 5 6 7 8 9 10 10 m/z 786.4512 1 unique peptide for apo(a) quantification by LC-MS/MS LFLEPTQ TQAD ADIALL ALLK = Pept QU QUANT Croyal et al. (2015) Arterioscler Thromb Vasc Biol Villard et al (2016) JACC Basic Transl Sci
CONCLUSION • PCSK9 is a natural circulating inhibitor of the LDLR. PCSK9 targets the receptor for degradation following endocytosis. • PCSK9 and LDLR genes are co-regulated by intracellular cholesterol content and statin treatment (mainly expressed in the liver). • Targeting plasma PCSK9 with mAbs lowers LDL-C as well as Lp(a) in clinical trials both in monotherapy and on top of statins. • We propose that PCSK9 does not significantly modulate Lp(a) catabolism but rather enhances the hepatic secretion of Lp(a), and that anti-PCSK9 mAbs reduce Lp(a) levels primarily by altering this pathway.
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