Deficiency of MMP1a (Matrix Metalloprotease 1a) Collagenase Suppresses Development of Atherosclerosis in Mice: Translational Implications for Human Coronary Artery Disease.

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PAR1 (Protease-Activated Receptor 1) Pepducin Therapy Targeting Myocardial Necrosis in Coronary Artery Disease and Acute Coronary Syndrome Patients Undergoing Cardiac Catheterization: A Randomized, Placebo-Controlled, Phase 2 Study.

OBJECTIVE: Arterial thrombosis leading to ischemic injury worsens the prognosis of many patients with cardiovascular disease. PZ-128 is a first-in-class pepducin that reversibly inhibits PAR1 (protease-activated receptor 1) on platelets and other vascular cells by targeting the intracellular surface of the receptor. The TRIP-PCI (Thrombin Receptor Inhibitory Pepducin in Percutaneous Coronary Intervention) trial was conducted to assess the safety and efficacy of PZ-128 in patients undergoing cardiac catheterization with intent to perform percutaneous coronary intervention. Approach and Results: In this randomized, double-blind, placebo-controlled, phase 2 trial, 100 patients were randomly assigned (2:1) to receive PZ-128 (0.3 or 0.5 mg/kg), or placebo in a 2-hour infusion initiated just before the start of cardiac catheterization, on top of standard oral antiplatelet therapy. Rates of the primary end point of bleeding were not different between the combined PZ-128 doses (1.6%, 1/62) and placebo group (0%, 0/35). The secondary end points of major adverse coronary events at 30 and 90 days did not significantly differ but were numerically lower in the PZ-128 groups (0% and 2% in the PZ-128 groups, 6% and 6% with placebo, p=0.13, p=0.29, respectively). In the subgroup of patients with elevated baseline cardiac troponin I, the exploratory end point of 30-day major adverse coronary events + myocardial injury showed 83% events in the placebo group versus 31% events in the combined PZ-128 drug groups, an adjusted relative risk of 0.14 (95% CI, 0.02-0.75); P=0.02. CONCLUSIONS: In this first-in-patient experience, PZ-128 added to standard antiplatelet therapy appeared to be safe, well tolerated, and potentially reduced periprocedural myonecrosis, thus providing the basis for further clinical trials. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02561000.

Noncanonical Matrix Metalloprotease 1-Protease-Activated Receptor 1 Signaling Drives Progression of Atherosclerosis.

OBJECTIVE: Protease-activated receptor-1 (PAR1) is classically activated by thrombin and is critical in controlling the balance of hemostasis and thrombosis. More recently, it has been shown that noncanonical activation of PAR1 by matrix metalloprotease-1 (MMP1) contributes to arterial thrombosis. However, the role of PAR1 in long-term development of atherosclerosis is unknown, regardless of the protease agonist. APPROACH AND RESULTS: We found that plasma MMP1 was significantly correlated (R=0.33; P=0.0015) with coronary atherosclerotic burden as determined by angiography in 91 patients with coronary artery disease and acute coronary syndrome undergoing cardiac catheterization or percutaneous coronary intervention. A cell-penetrating PAR1 pepducin, PZ-128, currently being tested as an antithrombotic agent in the acute setting in the TRIP-PCI study (Thrombin Receptor Inhibitory Pepducin-Percutaneous Coronary Intervention), caused a significant decrease in total atherosclerotic burden by 58% to 70% (P<0.05) and reduced plaque macrophage content by 54% (P<0.05) in apolipoprotein E-deficient mice. An MMP1 inhibitor gave similar beneficial effects, in contrast to the thrombin inhibitor bivalirudin that gave no improvement on atherosclerosis end points. Mechanistic studies revealed that inflammatory signaling mediated by MMP1-PAR1 plays a critical role in amplifying tumor necrosis factor α signaling in endothelial cells. CONCLUSIONS: These data suggest that targeting the MMP1-PAR1 system may be effective in tamping down chronic inflammatory signaling in plaques and halting the progression of atherosclerosis.

Cell-Penetrating Pepducin Therapy Targeting PAR1 in Subjects With Coronary Artery Disease.

OBJECTIVE: Pepducins are membrane-tethered, cell-penetrating lipopeptides that target the cytoplasmic surface of their cognate receptor. Here, we report the first human use of a protease-activated receptor-1-based pepducin, which is intended as an antiplatelet agent to prevent ischemic complications of percutaneous coronary interventions. APPROACH AND RESULTS: PZ-128 was administered by 1 to 2 hours continuous intravenous infusion (0.01-2 mg/kg) to 31 subjects with coronary artery disease or multiple coronary artery disease risk factors. Safety, antiplatelet efficacy, and pharmacokinetics were assessed at baseline and 0.5, 1, 2, 6, 24 hours, and 7 to 10 days postdosing. The inhibitory effects of PZ-128 on platelet aggregation stimulated by the protease-activated receptor-1 agonist SFLLRN (8 µmol/L) at 30 minutes to 6 hours were dose dependent with 20% to 40% inhibition at 0.3 mg/kg, 40% to 60% at 0.5 mg/kg, and ≥ 80% to 100% at 1 to 2 mg/kg. The subgroup receiving aspirin in the 0.5 and 1-mg/kg dose cohorts had 65% to 100% inhibition of final aggregation to SFLLRN at 30 minutes to 2 hours and 95% to 100% inhibition by 6 hours. The inhibitory effects of 0.5 mg/kg PZ-128 were reversible with 50% recovery of aggregation to SFLLRN by 24 hours. There were no significant effects of PZ-128 on aggregation induced by AYPGKF, ADP, or collagen, indicating that the observed effects were specific to protease-activated receptor-1. The plasma half-life was 1.3 to 1.8 hours, and PZ-128 was nondetectable in urine. There were no effects on bleeding, coagulation, clinical chemistry, or ECG parameters. CONCLUSIONS: PZ-128 is a promising antiplatelet agent that provides rapid, specific, dose dependent, and reversible inhibition of platelet protease-activated receptor-1 through a novel intracellular mechanism. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01806077.

Suppression of Heart Failure With PAR1 Pepducin Technology in a Pressure Overload Model in Mice.

BACKGROUND: PAR1 (protease-activated receptor-1) contributes to acute thrombosis, but it is not clear whether the receptor is involved in deleterious inflammatory and profibrotic processes in heart failure. Here, we employ the pepducin technology to determine the effects of targeting PAR1 in a mouse heart failure with reduced ejection fraction model. METHODS: After undergoing transverse aortic constriction pressure overload or sham surgery, C57BL/6J mice were randomized to daily sc PZ-128 pepducin or vehicle, and cardiac function, inflammation, fibrosis, and molecular analyses conducted at 7 weeks RESULTS: After 7 weeks of transverse aortic constriction, vehicle mice had marked increases in macrophage/monocyte infiltration and fibrosis of the left ventricle as compared with Sham mice. PZ-128 treatment significantly suppressed the inflammatory cell infiltration and cardiac fibrosis. Despite no effect on myocyte cell hypertrophy, PZ-128 afforded a significant reduction in overall left ventricle weight and completely protected against the transverse aortic constriction-induced impairments in left ventricle ejection fraction. PZ-128 significantly suppressed transverse aortic constriction-induced increases in an array of genes involved in myocardial stress, fibrosis, and inflammation. CONCLUSIONS: The PZ-128 pepducin is highly effective in protecting against cardiac inflammation, fibrosis, and loss of left ventricle function in a mouse model.