Recent Update on the Development of PCSK9 Inhibitors for Hypercholesterolemia Treatment

Cholesterol reduction by immunization with a PCSK9 mimic

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a plasma protein that controls cholesterol homeostasis. Here, we design a human PCSK9 mimic, named HIT01, with no consecutive 9-residue stretch in common with any human protein as a potential heart attack vaccine. Murine immunizations with HIT01 reduce low-density lipoprotein (LDL) and cholesterol levels by 40% and 30%, respectively. Immunization of cynomolgus macaques with HIT01-K21Q-R218E, a cleavage-resistant variant, elicits high-titer PCSK9-directed antibody responses and significantly reduces serum levels of cholesterol 2 weeks after each immunization. However, HIT01-K21Q-R218E immunizations also increase serum PCSK9 levels by up to 5-fold, likely due to PCSK9-binding antibodies altering the half-life of PCSK9. While vaccination with a PCSK9 mimic can induce antibodies that block interactions of PCSK9 with the LDL receptor, PCSK9-binding antibodies appear to alter homeostatic levels of PCSK9, thereby confounding its vaccine impact. Our results nevertheless suggest a mechanism for increasing the half-life of soluble regulatory factors by vaccination.

Recurrent Acute Coronary Syndrome in Young Man with Familial Hypercholesterolemia: Efficacy of Evolocumab Add-On Treatment Demonstrated via Serial Coronary Angiography

In patients with acute coronary syndrome (ACS), lipid-lowering therapy plays an important role in the prevention of the recurrence of cardiovascular disease. Recent guidelines recommend the use of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors in patients with ACS if their low-density lipoprotein cholesterol (LDL-C) levels are not adequately controlled with statins and ezetimibe. Based on this, we report a case in which administering a PCSK9 inhibitor successfully lowered the patient's LDL-C level to the target level and managed the coronary artery disease (CAD) recurrence. A 39-year-old man who was taking statins presented to the hospital with chest pain and was diagnosed with unstable angina. He started taking maximum doses of statins and ezetimibe to lower his LDL-C. However, the patient's unstable angina recurred 1 year later, and a de novo lesion with plaque rupture was demonstrated via coronary angiography. The LDL-C failed to reach the target level despite maintaining the maximum dose of statin and ezetimibe. Accordingly, evolocumab was initiated in addition to rosuvastatin/ezetimibe 20/10 mg daily. Subsequently, coronary angiography was performed twice, and on follow-up, the patient remained free of CAD recurrence. This case highlights the efficacy of lipid-lowering therapy with evolocumab in high-risk patients with repeated ACS.

The study on synthesis and vitro hypolipidemic activity of novel berberine derivatives nitric oxide donors

Berberine was used as the lead compound in the present study to design and synthesize novel berberine derivatives by splicing bromine bridges of different berberine carbon chain lengths coupled nitric oxide donors, and their lipid lowering activities were assessed in a variety of ways. This experiment synthesized 17 new berberine nitric oxide donor derivatives. Compared with berberine hydrochloride, most of the compounds exhibited certain glycerate inhibitory activity, and compounds 6a, 6b, 6d, 12b and 12d showed higher inhibitory activity than berberine, with 6a, 6b and 6d having significant inhibitory activity. In addition, compound 6a linked to furazolidone nitric oxide donor showed better NO release in experiments; In further mechanistic studies, we screened and got two proteins, PCSK9 and ACLY, and docked two proteins with 17 compounds, and found that most of the compounds bound better with ATP citrate lyase (ACLY), among which there may be a strong interaction between compound 6a and ACLY, and the interaction force was better than the target drug Bempedoic Acid, which meaning that 6a may exert hypolipidemic effects by inhibiting ACLY; moreover, we also found that 6a may had the better performance in gastrointestinal absorption, blood-brain barrier permeability, Egan, Muegge class drug principle model calculation and bioavailability.

BAY-9835: Discovery of the First Orally Bioavailable ADAMTS7 Inhibitor

The matrix metalloprotease ADAMTS7 has been identified by multiple genome-wide association studies as being involved in the development of coronary artery disease. Subsequent research revealed the proteolytic function of the enzyme to be relevant for atherogenesis and restenosis after vessel injury. Based on a publicly known dual ADAMTS4/ADAMTS5 inhibitor, we have in silico designed an ADAMTS7 inhibitor of the catalytic domain, which served as a starting point for an optimization campaign. Initially our inhibitors suffered from low selectivity vs MMP12. An X-ray cocrystal structure inspired us to exploit amino acid differences in the binding site of MMP12 and ADAMTS7 to improve selectivity. Further optimization composed of employing 5-membered heteroaromatic groups as hydantoin substituents to become more potent on ADAMTS7. Finally, fine-tuning of DMPK properties yielded BAY-9835, the first orally bioavailable ADAMTS7 inhibitor. Further optimization to improve selectivity vs ADAMTS12 seems possible, and a respective starting point could be identified.

Unraveling the Puzzle of Therapeutic Peptides: A Promising Frontier in Huntington's Disease Treatment

Huntington's disease (HD) is a neurodegenerative genetic disorder characterized by a mutation in the huntingtin (HTT) gene, resulting in the production of a mutant huntingtin protein (mHTT). The accumulation of mHTT leads to the development of toxic aggregates in neurons, causing cell dysfunction and, eventually, cell death. Peptide therapeutics target various aspects of HD pathology, including mHTT reduction and aggregation inhibition, extended CAG mRNA degradation, and modulation of dysregulated signaling pathways, such as BDNF/TrkB signaling. In addition, these peptide therapeutics also target the detrimental interactions of mHTT with InsP3R1, CaM, or Caspase-6 proteins to mitigate HD. This Perspective provides a detailed perspective on anti-HD therapeutic peptides, highlighting their design, structural characteristics, neuroprotective effects, and specific mechanisms of action. Peptide therapeutics for HD exhibit promise in preclinical models, but further investigation is required to confirm their effectiveness as viable therapeutic strategies, recognizing that no approved peptide therapy for HD currently exists.

Targeting proprotein convertase subtilisin/kexin type 9 (PCSK9): from bench to bedside

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has evolved as a pivotal enzyme in lipid metabolism and a revolutionary therapeutic target for hypercholesterolemia and its related cardiovascular diseases (CVD). This comprehensive review delineates the intricate roles and wide-ranging implications of PCSK9, extending beyond CVD to emphasize its significance in diverse physiological and pathological states, including liver diseases, infectious diseases, autoimmune disorders, and notably, cancer. Our exploration offers insights into the interaction between PCSK9 and low-density lipoprotein receptors (LDLRs), elucidating its substantial impact on cholesterol homeostasis and cardiovascular health. It also details the evolution of PCSK9-targeted therapies, translating foundational bench discoveries into bedside applications for optimized patient care. The advent and clinical approval of innovative PCSK9 inhibitory therapies (PCSK9-iTs), including three monoclonal antibodies (Evolocumab, Alirocumab, and Tafolecimab) and one small interfering RNA (siRNA, Inclisiran), have marked a significant breakthrough in cardiovascular medicine. These therapies have demonstrated unparalleled efficacy in mitigating hypercholesterolemia, reducing cardiovascular risks, and have showcased profound value in clinical applications, offering novel therapeutic avenues and a promising future in personalized medicine for cardiovascular disorders. Furthermore, emerging research, inclusive of our findings, unveils PCSK9's potential role as a pivotal indicator for cancer prognosis and its prospective application as a transformative target for cancer treatment. This review also highlights PCSK9's aberrant expression in various cancer forms, its association with cancer prognosis, and its crucial roles in carcinogenesis and cancer immunity. In conclusion, this synthesized review integrates existing knowledge and novel insights on PCSK9, providing a holistic perspective on its transformative impact in reshaping therapeutic paradigms across various disorders. It emphasizes the clinical value and effect of PCSK9-iT, underscoring its potential in advancing the landscape of biomedical research and its capabilities in heralding new eras in personalized medicine.

Construction of Nonnatural Cysteine-Cross-Linked Phage Libraries

Phage display is a powerful technique for rapid construction and screening of peptide libraries with over 109 sequence diversity. The M13 bacteriophage genome can be edited to incorporate randomized amino acids, which will be displayed on its minor coat protein (pIII). To enable screening of nonnatural cyclic peptides on phage, the minor coat protein can be modified with a chemical cross-linker. By taking advantage of the nucleophilicity and low abundance of free cysteines on phage, a variety of cysteine cross-linkers can be installed on the pIII protein. Here, we describe the construction of a chemically modified cyclic phage library through a cysteine cross-linking reagent, 1,3-dichloroacetone (DCA).

Optimization of the proportions of advantageous components in the hypolipidemic "bioequivalent substance system" of Jiang-Zhi-Ning and its mechanism of action

CONTEXT

Jiang-Zhi-Ning (JZN), a traditional Chinese medicinal formula, is used to treat hyperlipidemia in clinics.

OBJECTIVE

To screen the hypolipidemic "bioequivalent substance system (BSS)" of JZN and elucidate the potential hypolipidemic mechanism.

MATERIALS AND METHODS

In vitro, the TG content in HepG2 cells was determined after the intervention of the combination of advantageous components (CAC) by uniform design. In vivo, hyperlipidemia models were established by Triton WR-1339 (400 mg/kg; i.p.) in male ICR mice, and corresponding treatments were administered via oral administration once. The mice were divided into 12 groups (n = 5): control, hyperlipidemic model, simvastatin (positive control, 20 mg/kg), gradient doses of JZN granules (2, 4 and 8 g/kg) and the hypolipidemic effective extraction (HEE) of JZN (120, 240 and 480 mg/kg) and CAC groups (20, 40 and 160 mg/kg). Serum TC, TG, LDL-C and HDL-C were performed after 24 h. Transcriptomics and qRT-PCR technology were used to explore the mechanism of the "BSS" of JZN.

RESULTS

In vitro, the ratio of CAC was determined. CAC could reduce the TG content in HepG2 cells (77.21%). Compared with the model group, the high dose of CAC could markedly decrease the levels of TC (61.86%), TG (105.54%) and LDL-C (39.38%) and increase the level of HDL-C (232.67%). CAC was proved to be the "BSS". Transcriptomics and qRT-PCR analysis revealed CAC regulated non-alcoholic fatty liver disease, bile secretion, PPAR and adipocytokine signalling pathway.

DISCUSSION AND CONCLUSIONS

These findings provided new feasible ideas and methods for the elucidation of the pharmacodynamic material basis.

Beyond statins: New pharmacological targets to decrease LDL-cholesterol and cardiovascular events

The pharmacological treatment of dyslipidemia, a major modifiable risk factor for developing atherosclerotic cardiovascular disease (ASCVD), remains a debated and controversial issue, not only in terms of the most appropriate therapeutic range for lipid levels, but also with regard to the optimal strategy and sequence approach (stepwise vs upstream therapy). Current treatment guidelines for the management of dyslipidemia focus on the intensity of low-density lipoprotein cholesterol (LDL-C) reduction, stratified according to risk for developing ASCVD. Beyond statins and ezetimibe, different medications targeting LDL-C have been recently approved by regulatory agencies with potential innovative mechanisms of action, including proprotein convertase subtilisin/kexin type 9 modulators (monoclonal antibodies such as evolocumab and alirocumab; small interfering RNA molecules such as inclisiran), ATP-citrate lyase inhibitors (bempedoic acid), angiopoietin-like 3 inhibitors (evinacumab), and microsomal triglyceride transfer protein inhibitors (lomitapide). An understanding of their pharmacological aspects, benefit-risk profile, including impact on hard cardiovascular endpoints beyond LDL-C reduction, and potential advantages from the patient perspective (e.g., adherence) - the focus of this evidence-based review - is crucial for practitioners across medical specialties to minimize therapeutic inertia and support clinical practice.

Chromogranin A and its derived peptides: potential regulators of cholesterol homeostasis

Chromogranin A (CHGA), a member of the granin family of proteins, has been an attractive therapeutic target and candidate biomarker for several cardiovascular, neurological, and inflammatory disorders. The prominence of CHGA stems from the pleiotropic roles of several bioactive peptides (e.g., catestatin, pancreastatin, vasostatins) generated by its proteolytic cleavage and by their wide anatomical distribution. These peptides are emerging as novel modulators of cardiometabolic diseases that are often linked to high blood cholesterol levels. However, their impact on cholesterol homeostasis is poorly understood. The dynamic nature of cholesterol and its multitudinous roles in almost every aspect of normal body function makes it an integral component of metabolic physiology. A tightly regulated coordination of cholesterol homeostasis is imperative for proper functioning of cellular and metabolic processes. The deregulation of cholesterol levels can result in several pathophysiological states. Although studies till date suggest regulatory roles for CHGA and its derived peptides on cholesterol levels, the mechanisms by which this is achieved still remain unclear. This review aims to aggregate and consolidate the available evidence linking CHGA with cholesterol homeostasis in health and disease. In addition, we also look at common molecular regulatory factors (viz., transcription factors and microRNAs) which could govern the expression of CHGA and genes involved in cholesterol homeostasis under basal and pathological conditions. In order to gain further insights into the pathways mediating cholesterol regulation by CHGA/its derived peptides, a few prospective signaling pathways are explored, which could act as primers for future studies.

Synthesis of a Complex and Highly Potent PCSK9 Inhibitor

The solution-based gram-scale synthesis of complex and highly potent proprotein convertase subtilisin-like/kexin type 9 (PCSK9) inhibitor 1 is presented. Construction of Northern fragment 2, followed by stepwise installation of Eastern 3, Southern 4, and Western 5 fragments, provided macrocyclic precursor 19. This intermediate was cross-linked via an intramolecular azide-alkyne click reaction, which preceded macrolactamization to afford the core framework of compound 1. Finally, coupling with poly(ethylene glycol) side-chain-based 6 gave the PCSK9 inhibitor 1.

MK-0616: an oral PCSK9 inhibitor for hypercholesterolemia treatment

INTRODUCTION

Atherosclerotic cardiovascular disease (ASCVD) is a leading cause of morbidity and mortality worldwide. Lowering LDL-cholesterol, by lifestyle modification or therapeutically, reduces the risk of ASCVD. Proprotein convertase subtilisin/kexin type 9 (PCSK9), a protein which binds to the LDL-receptor and induces degradation, is a clinically validated target to lower LDL-cholesterol. Injectable PCSK9 inhibitor therapies have demonstrated substantial reductions in LDL-cholesterol with associated decreased risk of ASCVD events.

AREAS COVERED

MK-0616 is an orally bioavailable, renally excreted, macrocyclic peptide inhibitor of PCSK9. The article provides an understanding of the chemistry and development, pharmacokinetic and pharmacodynamic characteristics of MK-0616 and insight into its clinical efficacy and safety. In clinical trials, MK-0616 produced dose-dependent reductions in LDL-cholesterol, non-HDL-cholesterol, and apolipoprotein (apo) B levels. Furthermore, MK-0616 modestly lowered lipoprotein (a) [Lp(a)].

EXPERT OPINION

MK-0616 is a potent, oral macrocyclic peptide inhibitor of PCSK9 that is not only able to reduce LDL-cholesterol, non-HDL-cholesterol, and apoB, but can also lower Lp(a). Safety and tolerability studies reported to date are promising. MK-0616 may offer advantages over injectable anti-PCSK9 therapies in terms of ease of dosing, patient preference and cost. The results from phase III trials of MK-0616 on cardiovascular outcomes are awaited with interest.

Proprotein Convertase Subtilisin/Kexin Type 9 Inhibition: The Big Step Forward in Lipid Control

The breakthrough discovery of proprotein convertase subtilisin/kexin type 9 (PCSK9) 20 years ago revolutionised the current understanding of cholesterol homeostasis. Genetic studies have shown that gain-of-function mutations in PCSK9 lead to elevated LDL cholesterol and increased risk of atherosclerotic cardiovascular disease, while loss-of-function mutations in PCSK9 result in lifelong low levels of circulating LDL cholesterol and dramatic reduction in atherosclerotic cardiovascular disease. Therapies inhibiting PCSK9 lead to a higher density of LDL receptor on the surface of hepatocytes, resulting in greater ability to clear circulating LDL. Thus far, randomised controlled trials have shown that subcutaneous fully human monoclonal antibodies targeting PCSK9, evolocumab and alirocumab, and PCSK9 silencing with inclisiran result in drastic reductions in LDL cholesterol. Additionally, several novel strategies to target PCSK9 are in development, including oral antibody, gene silencing, DNA base editing and vaccine therapies. This review highlights the efficacy, safety and clinical use of these various approaches in PCSK9 inhibition.

Acute Coronary Syndrome: Disparities of Pathophysiology and Mortality with and without Peripheral Artery Disease

There are a number of devastating complications associated with peripheral artery disease, including limb amputations and acute limb ischemia. Despite the overlap, atherosclerotic diseases have distinct causes that need to be differentiated and managed appropriately. In coronary atherosclerosis, thrombosis is often precipitated by rupture or erosion of fibrous caps around atheromatous plaques, which leads to acute coronary syndrome. Regardless of the extent of atherosclerosis, peripheral artery disease manifests itself as thrombosis. Two-thirds of patients with acute limb ischemia have thrombi associated with insignificant atherosclerosis. A local thrombogenic or remotely embolic basis of critical limb ischemia may be explained by obliterative thrombi in peripheral arteries of patients without coronary artery-like lesions. Studies showed that thrombosis of the above-knee arteries was more commonly due to calcified nodules, which are the least common cause of luminal thrombosis associated with acute coronary events in patients with acute coronary syndrome. Cardiovascular mortality was higher in peripheral artery disease without myocardial infarction/stroke than in myocardial infarction/stroke without peripheral artery disease. The aim of this paper is to gather published data regarding the disparities of acute coronary syndrome with and without peripheral artery disease in terms of pathophysiology and mortality.

Exosomes, microvesicles, and other extracellular vesicles-a Keystone Symposia report

Extracellular vesicles (EVs) are small, lipid-bilayer-bound particles released by cells that can contain important bioactive molecules, including lipids, RNAs, and proteins. Once released in the extracellular environment, EVs can act as messengers locally as well as to distant tissues to coordinate tissue homeostasis and systemic responses. There is a growing interest in not only understanding the physiology of EVs as signaling particles but also leveraging them as minimally invasive diagnostic and prognostic biomarkers (e.g., they can be found in biofluids) and drug-delivery vehicles. On October 30-November 2, 2022, researchers in the EV field convened for the Keystone symposium "Exosomes, Microvesicles, and Other Extracellular Vesicles" to discuss developing standardized language and methodology, new data on the basic biology of EVs and potential clinical utility, as well as novel technologies to isolate and characterize EVs.

PCSK9 Inhibitors in Cancer Patients Treated with Immune-Checkpoint Inhibitors to Reduce Cardiovascular Events: New Frontiers in Cardioncology

Cancer patients treated with immune checkpoint inhibitors (ICIs) are exposed to a high risk of atherosclerosis and cardiometabolic diseases due to systemic inflammatory conditions and immune-related atheroma destabilization. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a key protein involved in metabolism of low-density lipoprotein (LDL) cholesterol. PCSK9 blocking agents are clinically available and involve monoclonal antibodies, and SiRNA reduces LDL levels in high-risk patients and atherosclerotic cardiovascular disease events in multiple patient cohorts. Moreover, PCSK9 induces peripheral immune tolerance (inhibition of cancer cell- immune recognition), reduces cardiac mitochondrial metabolism, and enhances cancer cell survival. The present review summarizes the potential benefits of PCSK9 inhibition through selective blocking antibodies and siRNA in patients with cancer, especially in those treated with ICIs therapies, in order to reduce atherosclerotic cardiovascular events and potentially improve ICIs-related anticancer functions.