Accelerating Proteomics Using Broad Specificity Proteases

Trypsin is the gold-standard protease in bottom-up proteomics, but many sequence stretches of the proteome are inaccessible to trypsin and standard LC-MS approaches. Thus, multienzyme strategies are used to maximize sequence coverage in post-translational modification profiling. We present fast and robust SP3- and STRAP-based protocols for the broad-specificity proteases subtilisin, proteinase K, and thermolysin. All three enzymes are remarkably fast, producing near-complete digests in 1-5 min, and cost 200-1000× less than proteomics-grade trypsin. Using FragPipe resolved a major challenge by drastically reducing the duration of the required "unspecific" searches. In-depth analyses of proteinase K, subtilisin, and thermolysin Jurkat digests identified 7374, 8178, and 8753 unique proteins with average sequence coverages of 21, 29, and 37%, including 10,000s of amino acids not reported in PeptideAtlas' >2400 experiments. While we could not identify distinct cleavage patterns, machine learning could distinguish true protease products from random cleavages, potentially enabling the prediction of cleavage products. Finally, proteinase K, subtilisin, and thermolysin enabled label-free quantitation of 3111, 3659, and 4196 unique Jurkat proteins, which in our hands is comparable to trypsin. Our data demonstrate that broad-specificity proteases enable quantitative proteomics of uncharted areas of the proteome. Their fast kinetics may allow "on-the-fly" digestion of samples in the future.

Gene Silencing of Angiopoietin-like 3 (ANGPTL3) Induced De Novo Lipogenesis and Lipid Accumulation in Huh7 Cell Line

Angiopoietin-like 3 (ANGPTL3) is a hepatokine acting as a negative regulator of lipoprotein lipase (LPL). Vupanorsen, an ANGPTL3 directed antisense oligonucleotide, showed an unexpected increase in liver fat content in humans. Here, we investigated the molecular mechanism linking ANGPTL3 silencing to hepatocyte fat accumulation. Human hepatocarcinoma Huh7 cells were treated with small interfering RNA (siRNA) directed to ANGPTL3, human recombinant ANGPTL3 (recANGPTL3), or their combination. Using Western blot, Oil Red-O, biochemical assays, and ELISA, we analyzed the expression of genes and proteins involved in lipid metabolism. Oil Red-O staining demonstrated that lipid content increased after 48 h of ANGPTL3 silencing (5.89 ± 0.33 fold), incubation with recANGPTL3 (4.08 ± 0.35 fold), or their combination (8.56 ± 0.18 fold), compared to untreated cells. This effect was also confirmed in Huh7-LX2 spheroids. A total of 48 h of ANGPTL3 silencing induced the expression of genes involved in the de novo lipogenesis, such as fatty acid synthase, stearoyl-CoA desaturase, ATP citrate lyase, and Acetyl-Coenzyme A Carboxylase 1 together with the proprotein convertase subtilisin/kexin 9 (PCSK9). Time-course experiments revealed that 6 h post transfection with ANGPTL3-siRNA, the cholesterol esterification by Acyl-coenzyme A cholesterol acyltransferase (ACAT) was reduced, as well as total cholesterol content, while an opposite effect was observed at 48 h. Under the same experimental conditions, no differences in secreted apoB and PCSK9 were observed. Since PCSK9 was altered by the treatment, we tested a possible co-regulation between the two genes. The effect of ANGPTL3-siRNA on the expression of genes involved in the de novo lipogenesis was not counteracted by gene silencing of PCSK9. In conclusion, our in vitro study suggests that ANGPTL3 silencing determines lipid accumulation in Huh7 cells by inducing the de novo lipogenesis independently from PCSK9.

Multiple Immunomodulatory Strategies Based on Targeted Regulation of Proprotein Convertase Subtilisin/Kexin Type 9 and Immune Homeostasis against Hepatocellular Carcinoma

Immunotherapy is the most promising systemic therapy for hepatocellular carcinoma. However, the outcome remains poor. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a role in altering cell-surface protein levels, potentially undermining the efficacy of immunotherapy against tumors. This highlights its potential as a target for antitumor therapy. Herein, CaCO3-based nanoparticles coencapsulated with DOX, an immunogenic cell death (ICD) inducer, and evolocumab was developed to enhanced the efficacy of immunotherapy. The obtained DOX/evolocumab-loaded CaCO3 nanoparticle (named DECP) exhibits a good capacity of acid neutralization and causes ICD of cancer cells. In addition, DECP is able to evaluate the cell-surface level of MHC-I, a biomarker that correlates positively with patients' overall survival. Upon intravenous injection, DECP accumulates within the tumor site, leading to growth inhibition of hepa1-6 bearing subcutaneous tumors. Specifically, DECP treatment causes augmented ratios of matured dendritic cells, tumor-infiltrating CD8+ T cells and natural killing cells, while concurrently depleting Foxp3+ regulatory T cells. Peritumoral delivery of DECP enhances the immune response of distant tumors and exhibits antitumor effects when combined with intravenous αPD-L1 therapy in a bilateral tumor model. This study presents CaCO3-based nanoparticles with multiple immunomodulatory strategies against hepatocellular carcinoma by targeting PCSK9 inhibition and modulating immune homeostasis in the unfavorable TME.

Potential use of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition and prevention method in viral infection

Cellular lipid membranes serve as the primary barrier preventing viral infection of the host cell and provide viruses with a critical initial point of contact. Occasionally, viruses can utilize lipids as viral receptors. Viruses depend significantly on lipid rafts for infection at virtually every stage of their life cycle. The pivotal role that proprotein convertase subtilisin/kexin Type 9 (PCSK9) plays in cholesterol homeostasis and atherosclerosis, primarily by post-transcriptionally regulating hepatic low-density lipoprotein receptor (LDLR) and promoting its lysosomal degradation, has garnered increasing interest. Conversely, using therapeutic, fully humanized antibodies to block PCSK9 leads to a significant reduction in high LDL cholesterol (LDL-C) levels. The Food and Drug Administration (FDA) has approved PCSK9 inhibitors, including inclisiran (Leqvio®), alirocumab (Praluent), and evolocumab (Repatha). At present, active immunization strategies targeting PCSK9 present a compelling substitute for passive immunization through the administration of antibodies. In addition to the current inquiry into the potential therapeutic application of PCSK9 inhibition in human immunodeficiency virus (HIV)-infected patients for hyperlipidemia associated with HIV and antiretroviral therapy (ART), preclinical research suggests that PCSK9 may also play a role in inhibiting hepatitis C virus (HCV) replication. Furthermore, PCSK9 inhibition has been suggested to protect against dengue virus (DENV) potentially and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viruses. Recent evidence regarding the impact of PCSK9 on a variety of viral infections, including HCV, HIV, DENV, and SARS-CoV-2, is examined in this article. As a result, PCSK9 inhibitors and vaccines may serve as viable host therapies for viral infections, as our research indicates that PCSK9 is significantly involved in the pathogenesis of viral infections.

Establishment of Golgi apparatus-related genes signature to predict the prognosis and immunotherapy response in gastric cancer patients

The Golgi apparatus plays a crucial role in intracellular protein transportation, processing, and sorting. Dysfunctions of the Golgi apparatus have been implicated in tumorigenesis and drug resistance. This study aimed to investigate the prognostic and treatment response assessment value of Golgi apparatus-related gene (GARGs) features in gastric cancer patients. Transcriptome data and clinical information of gastric cancer patients were obtained from The Cancer Genome Atlas and Gene Expression Omnibus databases. Cox regression analysis was employed to assess the prognostic significance of GARGs and construct risk features. The immune landscape, drug sensitivity, immune therapy response, gene expression patterns, and somatic mutation characteristics were analyzed between different risk groups. A nomogram model for predicting gastric cancer prognosis was developed and evaluated. Among 1643 GARGs examined, 365 showed significant associations with gastric cancer prognosis. Five independent prognostic GARGs (NGF, ABCG1, CHAC1, GBA2, PCSK7) were selected to construct risk features for gastric cancer patients. These risk features effectively stratified patients into high-risk and low-risk groups, with the former exhibiting worse prognosis than the latter. Patients in the high-risk group displayed higher levels of immune cell infiltration, while the expression levels of NGF, CHAC1, GBA2, PCSK7 were significantly correlated with immune cell infiltration. Notably, the low-risk group exhibited higher sensitivity to epothilone.B, metformin, and tipifarnib compared to the high-risk group. Moreover, patients in the low-risk group demonstrated greater responsiveness to immune therapy than those in the high-risk group. In terms of biological processes and KEGG pathways related to immunity regulation, significant suppression was observed in the high-risk group compared to the low-risk group; meanwhile cell cycle pathways exhibited significant activation in the high-risk group. Furthermore, the low-risk group exhibited a higher tumor mutation burden compared to the high-risk group. The risk features derived from GARGs, in conjunction with age, were identified as independent risk factors for gastric cancer. The nomogram incorporating these factors demonstrated improved performance in predicting gastric cancer prognosis. Our study established risk features derived from GARGs that hold potential clinical utility in prognostic assessment and immune therapy response evaluation of gastric cancer patients.

Genome-wide association study of blood lipid levels in Southern Han Chinese adults with prediabetes

Background

Dyslipidemia is highly prevalent among individuals with prediabetes, further exacerbating their cardiovascular risk. However, the genetic determinants underlying diabetic dyslipidemia in Southern Han Chinese remain largely unexplored.

Methods

We performed a genome-wide association study (GWAS) of blood lipid traits in 451 Southern Han Chinese adults with prediabetes. Fasting plasma lipids, including triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were assayed. Genotyping was conducted using the Precision Medicine Diversity Array and Gene Titan platform, followed by genotype imputation using IMPUTE2 with the 1000 Genomes Project (Phase 3, Southern Han Chinese) as reference. Single nucleotide polymorphisms (SNPs) associated with lipid levels were identified using mixed linear regression, with adjustment for covariates.

Results

We identified 58, 215, 74 and 81 novel SNPs associated with TG, TC, HDL-C and LDL-C levels, respectively (P < 5×10-5). Several implicated loci were located in or near genes involved in lipid metabolism, including SRD5A2, PCSK7, PITPNC1, IRX3, BPI, and LBP. Pathway enrichment analysis highlighted lipid metabolism and insulin secretion.

Conclusion

This first GWAS of dyslipidemia in Southern Han Chinese with prediabetes identified novel genetic variants associated with lipid traits. Our findings provide new insights into genetic mechanisms underlying heightened cardiovascular risk in the prediabetic stage. Functional characterization of implicated loci is warranted.

Function of proprotein convertase subtilisin/kexin type 9 and its role in central nervous system diseases: An update on clinical evidence

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has attracted lots of attention in preventing the clearance of plasma low-density lipoprotein cholesterol (LDL-C). PCSK9 inhibitors are developed to primarily reduce the cardiovascular risk by lowering LDL-C level. Recently, a number of pleiotropic extrahepatic functions of PCSK9 beyond the regulation of cholesterol metabolism, particularly its effects on central nervous system (CNS) diseases have been increasingly identified. Emerging clinical evidence have revealed that PCSK9 may play a significant role in neurocognition, depression, Alzheimer's disease, and stroke. The focus of this review is to elucidate the functions of PCSK9 and highlight the effects of PCSK9 in CNS diseases, with the aim of identifying the potential risks that may arise from low PCSK9 level (variant or inhibitor) in the clinical practice.

Effects of proprotein convertase subtilisin-kexin type 9 inhibitors on inflammatory and hemostatic parameters in post myocardial infarction patients

Despite progress in treatment, elevated levels of low-density lipoprotein cholesterol (LDL-C) and lipoprotein (a) (Lp(a)), represent a significant part of the residual risk. Both are associated with inflammation and the coagulation fibrinolytic system. The purpose of our research was to evaluate the effect of proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) on lipid parameters and indicators of inflammation, coagulation and fibrinolysis. We included 100 post myocardial infarction (MI) patients with insufficiently controlled LDL-C values despite the maximum dose of statin, and highly elevated Lp(a). Patients received alirocumab or evolocumab (150 mg sc or 140 mg sc every two weeks, respectively), or placebo for 6 months. In patients receiving PCSK9i, a significant decrease in total cholesterol (TC), LDL-C, triglycerides (TG) and Lp(a), and an increase in high density lipoprotein cholesterol (p < 0.001 for all) was found. Before treatment, the concentrations of TC, LDL-C and TG correlated with the concentrations of thrombin activatable fibrinolysis inhibitor (r = 0.41, p < 0.001; r = 0.353, p < 0.001; r = 0.311, p = 0.003, respectively), and plasminogen activator inhibitor-1 (r = 0.302, p = 0.007; r = 0.218, p = 0.049; r = 0.278; p = 0.013, respectively). The concentrations of TC and LDL-C correlated with overall fibrinolytic potential (r = -0.220, p = 0.034; r = -0.207, p = 0.047, respectively). The concentration of TG was related to the concentration of interleukin 6 (r = 0.290, p = 0.004) and interleukin 8 (r = 0.332, p = 0.001). No correlations between Lp(a) and inflammatory or hemostatic variables were found. No associations were found after treatment. Our results show that inflammatory cytokines and fibrinolytic parameters are related to LDL-C and not Lp(a) in post-MI patients before and with neither of them following PCSK9i treatment. The trial registration number: NCT04613167, Date of registration: November 3, 2020.

Discovery of (2-(4-Substituted phenyl)quinolin-4-yl)(4-isopropylpiperazin-1-yl)methanone Derivatives as Potent Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors

Inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) plays an increasingly important role in the treatment of hyperlipidemia. In pursuit of potent small molecules that block the PCSK9/low-density lipoprotein receptor (LDLR) protein-protein interaction (PPI), a series of 2-phenylquinoline-4-carboxylic acid derivatives were designed and synthesized based on previously derived molecules. In the in vitro PPI inhibition test, compounds M1, M12, M14, M18 and M27 exhibited potent activities with IC50 values of 6.25 μM, 0.91 μM, 2.81 μM, 4.26 μM and 0.76 μM, respectively, compared with SBC-115337 (IC50 value of 9.24 μM). Molecular docking and molecular dynamics simulations revealed the importance of hydrophobic interactions in the binding of inhibitors to the PPI interface of PCSK9. In LDLR expression and LDL uptake assays, the tested compounds M1, M12 and M14 were found to restore LDLR expression levels and to increase the extracellular LDL uptake capacity of HepG2 cells in the presence of exogenous PCSK9. Collectively, novel small-molecule PCSK9/LDLR PPI inhibitors (especially M12) with in vitro lipid lowering ability, were discovered as lead compounds for further development of hypolipidemic drugs.

Antioxidant, Antibacterial Properties of Novel Peptide CP by Enzymatic Hydrolysis of Chromis notata By-Products and Its Efficacy on Atopic Dermatitis

This study investigated the antioxidant, antimicrobial, and anti-atopic dermatitis (AD) effects of a novel peptide (CP) derived from a Chromis notata by-product hydrolysate. Alcalase, Flavourzyme, Neutrase, and Protamex enzymes were used to hydrolyze the C. notata by-product protein, and the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging activity was measured. Alcalase hydrolysate exhibited the highest ABTS radical-scavenging activity, leading to the selection of Alcalase for further purification. The CHAO-1-I fraction, with the highest ABTS activity, was isolated and further purified, resulting in the identification of the peptide CP with the amino acid sequence Ala-Gln-Val-Met-Lys-Leu-Pro-His-Arg-Met-Gln-His-Ser-Gln-Ser. CP demonstrated antimicrobial activity against Staphylococcus aureus, inhibiting its growth. In a 2,4-dinitrochlorobenzene (DNCB)-induced AD-like skin model in mice, CP significantly alleviated skin lesions, reduced epidermal and dermal thickness, and inhibited mast cell infiltration. Moreover, CP suppressed the elevated levels of interleukin-6 (IL-6) in the plasma of DNCB-induced mice. These findings highlight the potential of CP as a therapeutic agent for AD and suggest a novel application of this C. notata by-product in the fish processing industry.

Enzyme-Assisted Coextraction of Phenolics and Polysaccharides from Padina gymnospora

Brown seaweed is a promising source of polysaccharides and phenolics with industrial utility. This work reports the development of a green enzyme-assisted extraction method for simultaneously extracting polysaccharides and phenolics from the brown seaweed Padina gymnospora. Different enzymes (Cellulast, Pectinex, and Alcalase), individually and in combination, were investigated, with Alcalase alone showing the highest efficiency for the simultaneous extraction of polysaccharides and phenolics. Yields from Alcalase-assisted aqueous extraction were higher than those obtained using either water alone or conventional ethanol extraction. Alcalase-assisted extraction was subsequently optimized using a response surface methodology to maximize compound recovery. Maximal polysaccharide and phenolic recovery was obtained under the following extraction conditions: a water-to-sample ratio of 61.31 mL/g, enzyme loading of 0.32%, temperature of 60.5 °C, and extraction time of 1.95 h. The extract was then fractionated to obtain alginate-, fucoidan-, and phenolic-rich fractions. Fractions exhibited potent 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity with IC50 values of 140.55 µg/mL, 126.21 µg/mL, and 48.17 µg/mL, respectively, which were higher than those obtained from conventional extraction methods. The current work shows that bioactive polysaccharides and phenolics can be obtained together in high yield through a single aqueous-only green and efficient Alcalase-assisted extraction.

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.

Extracellular vesicle-mediated delivery of CRISPR/Cas9 ribonucleoprotein complex targeting proprotein convertase subtilisin-kexin type 9 (Pcsk9) in primary mouse hepatocytes

The loss-of-function of the proprotein convertase subtilisin-kexin type 9 (Pcsk9) gene has been associated with significant reductions in plasma serum low-density lipoprotein cholesterol (LDL-C) levels. Both CRISPR/Cas9 and CRISPR-based editor-mediated Pcsk9 inactivation have successfully lowered plasma LDL-C and PCSK9 levels in preclinical models. Despite the promising preclinical results, these studies did not report how vehicle-mediated CRISPR delivery inactivating Pcsk9 affected low-density lipoprotein receptor recycling in vitro or ex vivo. Extracellular vesicles (EVs) have shown promise as a biocompatible delivery vehicle, and CRISPR/Cas9 ribonucleoprotein (RNP) has been demonstrated to mediate safe genome editing. Therefore, we investigated EV-mediated RNP targeting of the Pcsk9 gene ex vivo in primary mouse hepatocytes. We engineered EVs with the rapamycin-interacting heterodimer FK506-binding protein (FKBP12) to contain its binding partner, the T82L mutant FKBP12-rapamycin binding (FRB) domain, fused to the Cas9 protein. By integrating the vesicular stomatitis virus glycoprotein on the EV membrane, the engineered Cas9 EVs were used for intracellular CRISPR/Cas9 RNP delivery, achieving genome editing with an efficacy of ±28.1% in Cas9 stoplight reporter cells. Administration of Cas9 EVs in mouse hepatocytes successfully inactivated the Pcsk9 gene, leading to a reduction in Pcsk9 mRNA and increased uptake of the low-density lipoprotein receptor and LDL-C. These readouts can be used in future experiments to assess the efficacy of vehicle-mediated delivery of genome editing technologies targeting Pcsk9. The ex vivo data could be a step towards reducing animal testing and serve as a precursor to future in vivo studies for EV-mediated CRISPR/Cas9 RNP delivery targeting Pcsk9.

Dual Action of Reduced Allergenicity and Improved Memory of Instant Soybean Powder Hydrolysates

Soy allergens are susceptible to inducing allergic reactions in infants and young animals, which have an impact on the effective daily utilization of proteins. In this study, we used Alcalase-hydrolyzed instant soybean powder (ISP) to clarify the sensitization changes of instant soybean powder hydrolysates (ISPH), and we explored the assisted memory-enhancing effects. BALB/c mice in the ISPH group showed significant improvement in the allergy symptoms, with their allergy symptom scores decreasing to (1.57 ± 0.53) and their specific serum IgE and IgG1 binding capacity decreasing by 28.00 and 25.73% (P < 0.05), which suppressed the mast cell degranulation rate. Meanwhile, the plasma HIS and IL-4 levels decreased by 12.59 and 25.32%, and the plasma INF-γ and IL- 10 levels increased by 30.64 and 27.79%, which obviously regulated the imbalance of Th1/Th2 cells and attenuated the tissue damage (P < 0.05). Furthermore, ISPH improved behavioral characteristics, increased cholinergic system activity, reduced neuronal cell damage or apoptosis, and increased the number of Nissl bodies to help improve memory in Kunming mice (P < 0.05). In general, alcalase-hydrolyzed ISP had the dual effects of reducing allergenicity and aiding in memory improvement.

Alcalase-Assisted Mytilus edulis Hydrolysate: A Nutritional Approach for Recovery from Muscle Atrophy

Muscle atrophy is a complex physiological condition caused by a variety of reasons, including muscle disuse, aging, malnutrition, chronic diseases, immobilization, and hormonal imbalance. Beyond its effect on physical appearance, this condition significantly reduces the quality of human life, thus warranting the development of preventive strategies. Although exercising is effective in managing this condition, it is applicable only for individuals who can engage in physical activities and are not bedridden. A combination of exercise and nutritional supplementation has emerged as a more advantageous approach. Here, we evaluated the effects of enzyme-assisted hydrolysates of Mytilus edulis prepared using Protamex (PMH), Alcalase (AMH), or Flavourzyme (FMH) in protecting against muscle atrophy in a dexamethasone (Dex)-induced muscular atrophy model in vitro and in vitro. Alcalase-assisted M. edulis hydrolysate (AMH) was the most efficient among the tested treatments and resulted in higher protein recovery (57.06 ± 0.42%) and abundant amino acid composition (43,158 mg/100 g; 43.16%). AMH treatment also escalated the proliferation of C2C12 cells while increasing the total number of nuclei, myotube coverage, and myotube diameter. These results were corroborated by a successful reduction in the levels of proteins responsible for muscle atrophy, including E3 ubiquitin ligases, and an increase in the expression of proteins associated with muscle hypertrophy, including myogenin and MyHC. These results were further solidified by the successful enhancement of locomotor ability and body weight in zebrafish following AMH treatment. Thus, these findings highlight the potential of AMH in recovery from muscle atrophy.

Efficacy of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitor Treatment for Repeated In-stent Restenosis in a Coronary Artery

A 57-year-old woman experienced chest pain. A coronary angiogram revealed middle left anterior descending artery stenosis. Despite receiving adequate anti-hyperlipidemia treatment and undergoing percutaneous coronary intervention (PCI), she experienced angina and required PCI six more times for in-stent restenosis. As she had high lipoprotein (a) [LP-(a)] levels at the seventh PCI procedure, proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9i) was administered, and a reduction in the LP-(a) and low-density lipoprotein cholesterol (LDL-C) values was observed. She experienced no recurrence of angina for five years with PCSK9i treatment. PCSK9i can reduce not only LDL-C but also LP-(a) levels, resulting in cardiac event risk reduction.

Antioxidant peptides generated from chicken feet protein hydrolysates

BACKGROUND

As major industrial poultry by-products, chicken feet are considered as notable sources of several bioactive molecules. The current work covers the processing of chicken feet proteins as substrates to be hydrolysed by combinations of three commercial enzymes (Alcalase®, Flavourzyme® and Protana® Prime) during different hydrolysis periods and the evaluation of the identified peptides having antioxidant activity after simulated gastrointestinal digestion.

RESULTS

Enzymatic hydrolysis with Alcalase® and Protana® Prime combination for 4 h resulted in the highest activities. Reversed-phase high-performance liquid chromatographic separation of the purified hydrolysate yielded three active fractions that were further identified by nano-liquid chromatography-tandem mass spectrometry. The bioactivities of over 230 identified peptide sequences were estimated after simulated gastrointestinal digestion, and those peptides with the highest chance of exerting antioxidant activity were selected to be further synthesised and tested. In this sense, the synthesised dipeptides CF and GY showed the highest antioxidant capacity. CF presented IC50 values of 69.63 and 145.41 μmol L-1 in 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and oxygen radical absorbance capacity (ORAC) assays, respectively. In contrast, GY IC50 values were 15.27 and 10.06 μmol L-1 in ABTS and ORAC assays, respectively. Significant differences (P < 0.05) were registered between peptides in the same antioxidant assays.

CONCLUSION

Overall, the findings emphasised the favourable impact of enzymatic hydrolysis with the obtaining of antioxidant peptides from poultry by-products that could be evaluated as a safe and economical source to retard oxidation in food systems. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Sex differences in efficacy and safety of PCSK9 monoclonal antibodies: A real-world registry

BACKGROUND AND AIMS

Proprotein convertase subtilisin/kexin 9 monoclonal antibodies (PCSK9 mAbs) reduce low-density lipoprotein (LDL-c) with a favourable safety profile. Available data from PCSK9 antibody trials suggest LDL-c reduction is lower in women compared to men. Data in real-world setting is scarce. The aim of this study was to assess sex differences in efficacy and safety of PCSK9 antibodies in clinical care.

METHODS

All patients starting with evolocumab or alirocumab in our lipid clinic were included in a prospective registry. We collected clinical information, including baseline and follow-up mean LDL-C levels after initiation of PCSK9 mAbs treatment. In addition, side effects and PCSK9 mAbs discontinuation were recorded.

RESULTS

We analysed 436 patients (209 women), mean age 58 ± 11 years. Women had higher baseline LDL-c levels compared to men (4.7 ± 1.6 mmol/L vs 4.1 ± 1.4 mmol/L, p < 0.01). PCSK9 mAbs resulted in less relative LDL-c reduction in women compared to men (50% vs 61% p<0.01), but equal absolute LDL-c reduction (respectively 2.3 ± 1.3 mmol/L vs 2.5 ± 1.1 mmol/L, p = 0.087). Women less often reached LDL-c target levels than men (50% vs 72%). No sex differences were observed in reporting of side effects (women 32% vs men 27% p = 0.26) or PCSK9 mAbs discontinuation (women 13% vs men 10%, p = 0.46).

CONCLUSIONS

In clinical practice, PCSK9 mAbs are less effective in reducing LDL-c levels in women compared to men and equally safe, implying the importance of sex differences in PCSK9 metabolism.

Impact of early initiation of proprotein convertase subtilisin/kexin type 9 inhibitors in patients with acute coronary syndrome: A systematic review meta-analysis

OBJECTIVE

Scant data is available on the efficacy and safety of proprotein convertase subtilisin/kexin type-9 inhibitors (PCSK9i) for early and rapid reduction of low-density lipoprotein cholesterol (LDL-C) within 4-8 weeks of an acute event in patients with acute coronary syndrome (ACS). We undertook this meta-analysis to address this knowledge-gap.

METHODS

Electronic databases were searched for RCTs involving patients with ACS receiving PCSK9i in intervention arm, and placebo/active comparator in control arm. Primary outcome was to evaluate changes in 1-month LDL-C post ACS. Secondary outcomes were to evaluate alterations in other lipid parameters and adverse events.

RESULTS

From initially screened 194 articles, data from 3 studies was analyzed. After 4-weeks therapy, patients receiving PCSK9i had lower LDL-C [MD -0.95 mmol/L (95%CI:-1.51 to -0.40); P = 0.0007; I2 = 96%, total cholesterol (TC) [MD-1.05 mmol/L (95%CI:-1.83 to -0.27); P = 0.009; I2 = 94%] and triglycerides (TG) [MD-0.27 mmol/L (95%CI:-0.44 to -0.10); P = 0.002; I2 = 0%] compared to controls. After 4-8 weeks therapy, patients receiving PCSK9i has lower apolipoprotein B [MD-27.74% (95%CI:-42.59 to -12.89); P = 0.0003; I2 = 89%] as compared to controls. High density lipoprotein cholesterol (HDL-C) [MD 0.05 mmol/L (95%CI:-0.00-0.11); P = 0.05; I2 = 0%], lipoprotein(a) [MD-20.63 mmol/L (95%CI:-41.86- 0.59); P = 0.06; I2 = 54%] and apolipoprotein A1 [MD 0.02 g/L (95%CI:-0.02-0.07); P = 0.32; I2 = 0%] were comparable between groups. Hospital readmission for ACS was significantly lower in group receiving PCSK9i compared to controls [OR0.25 (95%CI:0.07-0.85); P = 0.03; I2 = 0%]. Occurrence of cardiac death [OR3.75 (95%CI:0.41-34.22); P = 0.24; I2 = 0%], serious adverse events [OR0.71 (95% CI:0.13-3.83); P = 0.69; I2 = 70%] and total adverse events [OR1.01 (95%CI: 0.19-5.30); P = 0.99; I2 = 92%] was comparable between groups.

CONCLUSION

PCSK9i are highly effective in early reduction of LDL-C along with reduction of early hospital readmissions post-ACS.

Major cardiovascular events increase in long-term proprotein convertase subtilisin/kexin type 9 inhibitors therapy: the Tuscany cost-effective study

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) represent a breakthrough in the treatment of hypercholesterolemia. The aim of this study was to perform a multicentre prospective analysis on the effects of PCSK9i since their distribution in Italy.

METHODS

During the study period (July 2017 to February 2022) 246 patients (mean age 61 ± 11 years, male 73%) who were evolocumab (142/246) or alirocumab (104/246) new users were enrolled in the CERTI (Costo Efficacia Regione Toscana Inibitori PCSK9) study. Lipid value, adverse events (AEs), major cardiovascular events (MACEs) and intima-media thickness were analysed.

RESULTS

PCSK9i therapy allowed a significant improvement in patients' lipid profile [total cholesterol -35%, P < 0.001; triglycerides -9%, P < 0.05; low-density lipoprotein (LDL) cholesterol -51%, P < 0.001; Lp(a) levels -4%, P < 0.05], maintained during the follow-up. No significant variations in intima-media thickness were observed. In the subgroup of patients with more than 1 year of PCSK9i therapy (165/246 patients) we highlighted: a 66% reduction in MACEs compared with the year before recruitment; a progressive increase in MACEs during the follow-up (MACEs event/rate at first year 0.08 vs. MACEs event/rate at year 5: 0.47); a patients cluster with late MACEs older, with higher prevalence of hypertension, smoking habit and peripheral vascular disease. During the follow-up, we recorded AEs in 31% of patients, which mainly resulted in reduction/discontinuation of lipid-lowering therapy for 50 patients or in discontinuation/shift of PCSK9i (respectively 8 and 6 cases).

CONCLUSION

Our data agree with the large evidence on the effectiveness/tolerability of PCSK9i therapy; however, although PCSK9i represents a good cholesterol-lowering therapeutic option, our study shows a progressive increase in MACEs during the late follow-up that deserve further research.

PEER simplified lipid guideline 2023 update: Prevention and management of cardiovascular disease in primary care

OBJECTIVE

To update the 2015 clinical practice guideline and provide a simplified approach to lipid management in the prevention of cardiovascular disease (CVD) for primary care.

METHODS

Following the Institute of Medicine's Clinical Practice Guidelines We Can Trust, a multidisciplinary, pan-Canadian guideline panel was formed. This panel was represented by primary care providers, free from conflicts of interest with industry, and included the patient perspective. A separate scientific evidence team performed evidence reviews on statins, ezetimibe, proprotein convertase subtilisin-kexin type 9 inhibitors, fibrates, bile acid sequestrants, niacin, and omega-3 supplements (docosahexaenoic acid with eicosapentaenoic acid [EPA] or EPA ethyl ester alone [icosapent]), as well as on 11 supplemental questions. Recommendations were finalized by the guideline panel through use of the Grading of Recommendations Assessment, Development and Evaluation methodology.

RECOMMENDATIONS

All recommendations are presented in a patient-centred manner designed with the needs of family physicians and other primary care providers in mind. Many recommendations are similar to those published in 2015. Statins remain first-line therapy for both primary and secondary CVD prevention, and the Mediterranean diet and physical activity are recommended to reduce cardiovascular risk (primary and secondary prevention). The guideline panel recommended against using lipoprotein a, apolipoprotein B, or coronary artery calcium levels when assessing cardiovascular risk, and recommended against targeting specific lipid levels. The team also reviewed new evidence pertaining to omega-3 fatty acids (including EPA ethyl ester [icosapent]) and proprotein convertase subtilisin-kexin type 9 inhibitors, and outlined when to engage in informed shared decision making with patients on interventions to lower cardiovascular risk.

CONCLUSION

These updated evidence-based guidelines provide a simplified approach to lipid management for the prevention and management of CVD. These guidelines were created by and for primary health care professionals and their patients.

Development of Novel Monoclonal Antibodies Against Nattokinase

Nattokinase is a protease produced by Bacillus subtilis var. natto that exhibits various beneficial biological effects. Thus, a reliable assay to determine nattokinase levels is needed. In this study, we developed novel mouse monoclonal antibodies (mAbs) that recognize nattokinase, and created a specific and sensitive enzyme-linked immunosorbent assay (ELISA) to measure nattokinase levels. The ELISA was developed using a combination of new mouse antinattokinase mAbs used as capture antibodies coated onto 96-well plates, with a peroxidase-conjugated antibody used for detection. This ELISA enabled detection of nattokinase at 1 ng/mL. We believe that the novel mAbs developed in this study will be useful in future for elucidating nattokinase function.

Real-World Analyses of the Treatment Conditions in Patients Initiating Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) Inhibitor in Taiwan

AIMS

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor is a powerful low density lipoprotein cholesterol (LDL-C)-lowering therapy, but this drug is expensive. This study aimed to describe the real-world treatment conditions in patients initiating PCSK9 inhibitor in Taiwan.

METHODS

This was a multicenter, retrospective, and observational study. The clinical characteristics, baseline lipid-lowering therapy, and changes in the lipid profile of patients receiving PCSK9 inhibitor treatment were obtained from 11 major teaching hospitals in Taiwan.

RESULTS

A total of 296 patients (age 57±13 years, male 73%) who received PCSK9 inhibitor treatments (73.3% alirocumab and 26.7% evolocumab) from 2017 to 2021 were included. Among the patients, 62.8% had history of coronary artery disease, and 27.7% had myocardial infarction. High intensity statin (HIS) monotherapy or HIS＋ezetimibe treatment was used in 32.5% when initiating PCSK9 inhibitor treatment. Among alirocumab users, 21.2% received 75 mg every 3 to 4 weeks, whereas among evolocumab users, 8.9% received 140 mg every 3 to 4 weeks. Almost all the non-standard-dosing PCSK9 inhibitors were paid by the patients themselves but were not reimbursed by the Taiwan National Health Insurance. Overall, the LDL-C levels at baseline and 12 weeks after treatment were 147.4±67.4 and 69.7±58.2 mg/dL (p＜0.01), corresponding to a 49.6%±31.8% LDL-C reduction.

CONCLUSIONS

In the real-world practice in Taiwan, the LDL-C reduction efficacy of PCSK9 inhibitors was slightly lower than that reported in the clinical trials. The use of non-standard-dosing PCSK9 inhibitors was not uncommon in Taiwan.

Predictors of functional and morphological arterial wall properties in coronary artery disease patients with increased lipoprotein (a) levels before and after treatment with proprotein convertase subtilisin-kexin type 9 inhibitors

BACKGROUND

In addition to proatherogenic properties, lipoprotein (a) (Lp(a)) has also pro-inflammatory, antifibrinolytic and prothrombogenic features. The aim of the current study was to identify the predictors of functional and morphological properties of the arterial wall in patients after myocardial infarction and increased Lp(a) levels at the beginning and after treatment with proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors.

METHODS

Seventy-six post-myocardial infarction patients with high Lp(a) levels were included in the study. Ultrasound measurements of flow-mediated dilation of brachial artery (FMD), carotid intima-media thickness (c-IMT) and pulse wave velocity (PWV) were performed initially and after 6 months of treatment. At the same time points lipids, Lp(a), inflammatory and hemostasis markers were measured in blood samples.

RESULTS

In linear regression model FMD significantly correlated with age at first myocardial infarction (β = 0.689; p = 0.022), high-sensitivity C-reactive protein (β = -1.200; p = 0.009), vascular cell adhesion protein 1 (VCAM-1) (β = -0.992; p = 0.006), overall coagulation potential (β = 1.428; p = 0.014) and overall hemostasis potential (β = -1.473; p = 0.008). c-IMT significantly correlated with age at first myocardial infarction (β = 0.574; p = 0.033) and Lp(a) (β = 0.524; p = 0.040). PWV significantly correlated with systolic blood pressure (β = 0.332; p = 0.002), tumor necrosis factor alpha (β = 0.406; p = 0.002), interleukin-8 (β = -0.315; p = 0.015) and plasminogen activator inhibitor 1 (β = 0.229; p = 0.031). After treatment FMD reached statistical significance only in univariant analysis with systolic blood pressure (r = -0.286; p = 0.004) and VCAM-1 (r = -0.229; p = 0.024). PWV and c-IMT correlated with age (r = 0.334; p = 0.001 and r = 0.486; p < 0.0001, respectively) and systolic blood pressure (r = 0.556; p < 0.0001 and r = 0.233; p = 0.021, respectively).

CONCLUSIONS

Our results suggest that age, systolic blood pressure, Lp(a) levels and other biochemical markers associated with Lp(a) are predictors of functional and morphological properties of the arterial vessel wall in post-myocardial patients with high Lp(a) levels initially. However, after 6 months of treatment with PCSK9 inhibitors only age and systolic blood pressure seem to be predictors of these properties.

TRIAL REGISTRATION

The protocol for this study was registered with clinicaltrials.gov on November, 3 2020 under registration number NCT04613167.

[Effect of proprotein convertase subtilisin/kexin type 9 on platelet activation associated with sepsis]

OBJECTIVE

To investigate the effect of proprotein convertase subtilisin/kexin type 9 (PCSK9) on platelet activation in sepsis.

METHODS

(1) Clinical trial: a prospective study was conducted. Patients with sepsis and septic shock aged ≥ 18 years old who met the diagnostic criteria of Sepsis-3 admitted to the department of intensive care medicine of the Affiliated Hospital of Binzhou Medical College from January to October in 2021 were selected as subjects. Healthy subjects in the same period were taken as healthy control group. Platelet count (PLT) in the first routine blood test after admission was recorded. Venous blood was taken 1 day after diagnosis, and serum PCSK9 level was determined by enzyme-linked immunosorbent assay (ELISA). The differences of PCSK9 level and PLT between the two groups were compared, and subgroup analysis was conducted based on PLT for patients with sepsis. The correlation between PCSK9 level and PLT in septic patients was analyzed by Pearson correlation method. (2) Animal experiment: 80 male C57BL/6 mice were randomly divided into control group, sepsis model group [lipopolysaccharide (LPS) group], PCSK9 inhibitor pretreatment group (PCSK9 inhibitor+LPS group) and PCSK9 inhibitor control group (PCSK9 inhibitor group), with 20 mice in each group. The mouse model of sepsis was reproduced by intraperitoneal injection of LPS 12 mg/kg, and the control group and PCSK9 inhibitor group were intraperitoneally injected with the same amount of sterile normal saline. PCSK9 inhibitor+LPS group and PCSK9 inhibitor group were pretreated with PCSK9 inhibitor 5 mg/kg intraperitoneal injection for 7 days before injection of LPS or normal saline, respectively, and the control group and LPS group were injected with an equal amount of sterile normal saline. The lung tissues were taken for pathological and immunohistochemical observation 24 hours after modeling. Blood was taken from the heart for determining PLT. Platelet activation was detected by flow cytometry. The expression level of platelet-activation marker CD40L was detected by Western blotting.

RESULTS

(1) Clinical trial: there were 57 cases in the sepsis group and 27 cases in the healthy control group. Serum PCSK9 level in the sepsis group was significantly higher than that in the healthy control group (μg/L: 232.25±72.21 vs. 191.72±54.92, P < 0.05), and PLT was significantly lower than that in the healthy control group [×109/L: 146.00 (75.50, 204.50) vs. 224.00 (194.00, 247.00), P < 0.01]. Subgroup analysis showed that the serum PCSK9 level in the thrombocytopenia patients (n = 20) was significantly higher than that in the non-thrombocytopenia patients (n = 37; μg/L: 264.04±60.40 vs. 215.06±72.95, P < 0.01). Correlation analysis showed a significant negative correlation between serum PCSK9 levels and PLT in septic patients (r = -0.340, P = 0.010). (2) Animal experiment: there were no significant pathological changes in lung tissue in the control group and PCSK9 inhibitor group under light microscope, and no significant differences in PLT, platelet activation and plasma CD40L protein expression was found between the two groups. In the LPS group, a large number of inflammatory cells were infiltrated in the pulmonary interstitium, the alveolar structure was damaged obviously, the alveolar septum was widened, the alveolar cavity was extensively bleeding, the capillary dilatation with bleeding and platelet aggregation were found, the PLT was significantly decreased, the platelet activation and the expression level of CD40L protein in plasma were significantly increased. The infiltration of inflammatory cells in lung tissue of mice in the PCSK9 inhibitor+LPS group was reduced to a certain extent, the thickening of alveolar septa was reduced, the platelet aggregation in lung tissue was decreased as compared with the LPS group, the PLT was significantly increased (×109/L: 515.83±46.60 vs. 324.83±46.31, P < 0.05), the platelet activation and the expression level of CD40L protein in plasma were significantly decreased [positive expression rate of platelet activation dependent granule surface facial mask protein CD62P: (12.15±1.39)% vs. (18.33±2.74)%, CD40L protein (CD40L/β-actin): 0.77±0.08 vs. 1.18±0.10, both P < 0.05].

CONCLUSIONS

PCSK9 level has a certain effect on promoting platelet activation in sepsis, and inhibition of PCSK9 level may have potential research value in improving adverse outcomes caused by sepsis thrombocytopenia.

Proprotein convertase subtilisin/kexin type 6 (PCSK6) is a likely antigenic target in membranous nephropathy and nonsteroidal anti-inflammatory drug use

Drugs are an important secondary cause of membranous nephropathy (MN) with the most common drugs associated with MN being nonsteroidal anti-inflammatory drugs (NSAIDs). Since the target antigen in NSAID-associated MN is not known, we performed laser microdissection of glomeruli followed by mass spectrometry (MS/MS) in 250 cases of PLA2R-negative MN to identify novel antigenic targets. This was followed by immunohistochemistry to localize the target antigen along the glomerular basement membrane and western blot analyses of eluates of frozen biopsy tissue to detect binding of IgG to the novel antigenic target. MS/MS studies revealed high total spectral counts of a novel protein Proprotein Convertase Subtilisin/Kexin Type 6 (PCSK 6) in five of the 250 cases in the discovery cohort. A validation cohort using protein G immunoprecipitation, MS/MS, and immunofluorescence detected PCSK6 in eight additional cases. All cases were negative for known antigens. Ten of 13 cases had a history of heavy NSAID use with no history available in one case. The mean serum creatinine and proteinuria at kidney biopsy were 0.93 ± 0.47 mg/dL and 6.5 ± 3.3 gms/day, respectively. Immunohistochemistry/immunofluorescence showed granular staining for PCSK6 along the glomerular basement membrane, and confocal microscopy showed co-localization of IgG and PCSK6. IgG subclass analysis in three cases revealed codominance of IgG1 and IgG4. Western blot analysis using eluates from frozen tissue showed IgG binding to PCSK6 in PCSK6-associated but not in PLA2R-positive MN. Thus, PCSK6 may be a likely novel antigenic target in MN in patients with prolonged NSAID use.

Effect of proprotein convertase subtilisin/kexin type 9 inhibition on cancer events: A pooled, post hoc, competing risk analysis of alirocumab clinical trials

OBJECTIVE

Assess the risk of new and worsening cancer events among participants who received the lipid-lowering therapy alirocumab, a proprotein convertase subtilisin/kexin type 9 inhibitor.

DESIGN

Pooled post hoc analysis.

SETTING

Six phase 3 or phase 4 placebo-controlled randomised trials with alirocumab.

PARTICIPANTS

A total of 24,070 patients from the safety population with complete dosing data (alirocumab, n = 12,533; placebo, n = 11,537).

INTERVENTION

Alirocumab 75 mg, alirocumab 150 mg, alirocumab 75 mg increasing to 150 mg if low-density lipoprotein cholesterol <50 mg/dL not achieved, or placebo, all every 2 weeks. All participants received background high-intensity or maximum-tolerated statin therapy.

OUTCOMES AND MEASURES

The first new or worsening incident cancer events were assessed during the treatment-emergent adverse event period. Four outcomes were evaluated: any-neoplasm, malignant neoplasms, broad definition of hormone-sensitive cancers, and stricter definition of hormone-sensitive cancers. Sub-distribution hazard ratios and 95% confidence intervals (CIs) were estimated using a competing risk framework, with death as a competing risk.

RESULTS

Considering both treatment arms in aggregate, 969 (4.03%), 779 (3.24%), 178 (0.74%) and 167 (0.69%) patients developed any neoplasm, malignant neoplasms, broad definition of hormone-sensitive cancer and strict definition of hormone-sensitive cancer events, respectively. There was no significant difference in the risk of having any neoplasm in the alirocumab versus the placebo group (sub-distribution hazards ratio [95% CI], 0.93 [0.82-1.1]; p = 0.28). A nominally lower risk of having any neoplasms with alirocumab was observed among subjects aged ≥64 years (sub-distribution hazards ratio 0.83; 95% CI, 0.70-0.99).

CONCLUSIONS

Intensive low-density lipoprotein cholesterol lowering with a proprotein convertase subtilisin/kexin type 9 inhibitor combined with statin does not appear to increase the risk of new or worsening cancer events.

Discovery of [5,5'-bibenzo[d][1,3]dioxol]-6-substituted amine derivatives as potent proprotein convertase subtilisin/kexin type 9 inhibitors

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has emerged as a promising therapeutic target for the treatment of hyperlipidemia. In discovery of novel small molecules that interfere PCSK9/LDLR protein-protein interaction (PPI), structural modification was performed based on our previously derived compounds. A series of [5,5'-bibenzo[d][1,3]dioxol]-6-amine analogs were designed and synthesized for the activity evaluation. In the PCSK9/LDLR PPI impairing test, molecules D28 and D29, exhibited remarkable inhibitory potency with IC50 values of 8.30 and 6.70 μM compared with SBC-115337 (17.89 μM), respectively. Molecular docking predicted the binding pattern of compounds D28 and D29 in the LDLR binding site of PCSK9. Hydrophobic interactions play an important role in the binding of aromatic molecular fragments to the pockets in the PCSK9/LDLR binding interface. Further LDLR expression and LDL uptake studies revealed that both D28 and D29 restored LDLR expression on the surface of hepatic HepG2 cells and improved extracellular LDL uptake in the presence of PCSK9. It is significant that molecules D28 and D29 exhibited potential for the treatment of hyperlipidemia in current in vitro investigations. Generally, lead compounds with novel structures were developed in the present study for further design of lipid-lowering molecules by targeting PCSK9/LDLR PPI.

Effect of Different Types and Dosages of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors on Lipoprotein(a) Levels: A Network Meta-analysis

ABSTRACT

Lipoprotein(a) [Lp(a)] has become an important component of the residual risk of cardiovascular diseases. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors display promising effects in controlling Lp(a) levels. However, the effects of different types and dosages of PCSK9 inhibitors on Lp(a) have not been studied in detail. These include 2 monoclonal antibodies, alirocumab and evolocumab, and inclisiran, a small interfering RNA. We searched PubMed, Web of Science, Embase, and Cochrane Library for randomized controlled trials to investigate the efficacy of PCSK9 inhibitors at the Lp(a) level. Although changes in Lp(a) levels were not the primary endpoint in any of these studies, they all described these valuable data. Forty-one randomized controlled trials with 17,601 participants were included, involving 23 unduplicated interventions. Most PCSK9 inhibitors significantly reduced Lp(a) levels compared with placebo. The pairwise comparison demonstrated no significant difference among most PCSK9 inhibitors. However, in the comparison among different dosages of alirocumab, the dosage of 150 mg Q2W showed a significant reduction in Lp(a) levels compared with the dosages of 150, 200, and 300 mg Q4W. In addition, the comparison results demonstrated the significant efficacy of evolocumab 140 mg Q2W compared with alirocumab at a dosage of 150 mg Q4W. The cumulative rank probabilities demonstrated that evolocumab 140 mg Q2W showed the highest efficacy. This study showed that PCSK9 inhibitors reduced Lp(a) levels by up to 25.1%. A biweekly dose of either 140 mg evolocumab or 150 mg alirocumab was the best treatment option. However, the reduction in Lp(a) levels with a single kind of PCSK9 inhibitor alone did not demonstrate sufficient clinical benefit. Therefore, for patients with very high Lp(a) levels who remain at high residual risk in the context of statin administration, it may be acceptable to use a kind of PCSK9 inhibitor, but the clinical benefit needs further investigation.

Novel Hypocholesterolemic Peptides Derived from Silver Carp Muscle: The Modulatory Effects on Enterohepatic Cholesterol Metabolism In Vitro and In Vivo

This research aimed to investigate the effect of silver carp hydrolysates (SCHs) on hypercholesterolemia and enterohepatic cholesterol metabolism. Results showed that in vitro gastrointestinal digestion products of Alcalase-SCH (GID-Alcalase) exhibited the highest inhibitory activity of cholesterol absorption mainly through downregulating the expression of essential genes related to cholesterol transport in a Caco-2 monolayer. After being absorbed by the Caco-2 monolayer, GID-Alcalase increased the low-density lipoprotein (LDL) uptake in HepG2 cells by enhancing the protein level of the LDL receptor (LDLR). The in vivo experiment showed that long-term intervention of Alcalase-SCH ameliorated hypercholesterolemia in ApoE^-/- mice fed with a Western diet (WD). After transepithelial transport, four novel peptides (TKY, LIL, FPK, and IAIM) were identified, and these peptides possessed dual hypocholesterolemic functions including inhibition of cholesterol absorption and promotion of peripheric LDL uptake. Our results indicated for the first time the potential of SCHs as functional food ingredients for the management of hypercholesterolemia.

Interplay between microRNAs, Serum Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9), and Lipid Parameters in Patients with Very High Lipoprotein(a) Treated with PCSK9 Inhibitors

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has an important function in the regulation of lipid metabolism. PCSK9 reduces hepatic low-density lipoprotein receptors, thereby increasing low-density lipoprotein cholesterol levels. However, its regulation remains to be elucidated, including post-transcriptional regulation by microRNAs (miRNAs). We aimed to explore the interplay between miRNAs, total serum PCSK9, and lipids during treatment with PCSK9 inhibitors. A total of 64 patients with stable coronary artery disease and very high lipoprotein(a) levels and 16 sex- and age-matched control subjects were enrolled. Patients received a PCSK9 inhibitor (evolocumab or alirocumab). Total serum PCSK9 levels were measured by immunoassay. RNA was isolated from plasma using magnetic beads, and expression of selected miRNAs was analyzed by quantitative PCR. Total serum PCSK9 levels were significantly higher in control subjects compared with patients. After 6 months of treatment with PCSK9 inhibitors, total serum PCSK9 levels increased significantly. The expression of miR-191-5p was significantly lower, and the expression of miR-224-5p and miR-483-5p was significantly higher in patients compared with control subjects. Using linear regression, the expression of miR-483-5p significantly predicted the serum PCSK9 level at baseline. After the 6-month period of therapy, the expression of miR-191-5p and miR-483-5p significantly increased. Our results support a role for miR-483-5p in regulating circulating PCSK9 in vivo. The difference in expression of miR-191-5p, miR-224-5p, and miR-337-3p between patients and control subjects suggests their possible role in the pathogenesis of coronary artery disease.

Role of the Subtilisin-like Serine Protease CJPRB from Cordyceps javanica in Eliciting an Immune Response in Hyphantria cunea

Hyphantria cunea is a globally distributed quarantine plant pest. In a previous study, the Cordyceps javanica strain BE01 with a strong pathogenic effect on H. cunea was identified, and overexpression of the subtilisin-like serine protease CJPRB of this strain was found to accelerate the death of H. cunea (previous research results). In this study, the active recombinant CJPRB protein was obtained through the Pichia pastoris expression system. It was found that CJPRB protein administration to H. cunea via infectation, feeding and injection was able to induce changes in protective enzymes, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and polyphenol oxidase (PPO), and the expression of immune defense-related genes in H. cunea. In particular, CJPRB protein injection induced a more rapid, widespread and intense immune response in H. cunea compared to the other two treatment methods. The results suggest that the CJPRB protein may play a role in eliciting a host immune response during infectation by C. javanica.

Heparin Does Not Regulate Circulating Human PCSK9 (Proprotein Convertase Subtilisin-Kexin Type 9) in a General Population-Brief Report

BACKGROUND

PCSK9 (proprotein convertase subtilisin-kexin type 9) chaperones the hepatic LDLR (low-density lipoprotein receptor) for lysosomal degradation, elevating serum LDL (low-density lipoprotein) cholesterol and promoting atherosclerotic heart disease. Though the major effect on the hepatic LDLR comes from secreted PCSK9, the details of PCSK9 reuptake into the hepatocyte remain unclear. In both tissue culture and animal models, HSPGs (heparan sulfate proteoglycans) on hepatocytes act as co-receptors to promote PCSK9 reuptake. We hypothesized that if this PCSK9:HSPG interaction is important in humans, disrupting it with unfractionated heparin (UFH) would acutely displace PCSK9 from the liver and increase plasma PCSK9.

METHODS

We obtained remnant plasma samples from 160 subjects undergoing cardiac catheterization before and after administration of intravenous UFH. PCSK9 levels were determined using a commercial enzyme-linked immunosorbent assay.

RESULTS

Median plasma PCSK9 was 113 ng/mL prior to UFH and 119 ng/mL afterward. This difference was not significant (P=0.83 [95% CI, -6.23 to 6.31 ng/mL]). Equivalence testing provided 95% confidence that UFH would not raise plasma PCSK9 by > 4.7%. Among all subgroups, only subjects with the lowest baseline PCSK9 concentrations exhibited a response to UFH (8.8% increase, adj. P=0.044). A modest correlation was observed between baseline plasma PCSK9 and the change in plasma PCSK9 due to UFH (RS=-0.3634; P<0.0001).

CONCLUSIONS

Administration of UFH does not result in a clinically meaningful effect on circulating PCSK9 among an unselected population of humans. The results cast doubt on the clinical utility of disrupting the PCSK9:HSPG interaction as a general therapeutic strategy for PCSK9 inhibition. However, the observations suggest that in selected populations, disrupting the PCSK9:HSPG interaction could still affect PCSK9 reuptake and offer a therapeutic benefit.

Rice Endoplasmic Protein-Derived Peptides, Rice-Ghretropins A and B, Stimulate Ghrelin Release in MGN3-1 Cells and Increase Plasma Acylated Ghrelin and Food Intake in Mice

In this study, we demonstrated that novel rice-derived bioactive peptides promote the secretion of ghrelin, an endogenous orexigenic hormone secreted from the stomach. The enzymatic digest of rice endosperm protein with subtilisin, a microorganism-derived enzyme, stimulated acylated ghrelin secretion in the ghrelin-releasing cell line MGN3-1 and increased food intake after oral administration in mice. By performing a comprehensive analysis based on structure-activity relationships, we selected candidate peptides from over 30,000 peptides in the rice digest. Among them, we found that QAFEPIRSV and TNPWHSPRQGSF, corresponding to the amino acid sequence of the rice endoplasmic proteins glutelin A1 or A2(52-60) and B1 or B2(31-42), respectively, stimulated acylated ghrelin release in MGN3-1 cells. We named them rice-ghretropins A and B. Pyroglutamate formation of rice-ghretropin A, [pyr¹]-rice-ghretropin A, also promoted ghrelin secretion. Furthermore, oral administration of rice-ghretropins increased food intake, plasma ghrelin concentration, and small intestinal transit in mice. In addition, the subtilisin digest of the rice protein significantly increased food intake for 4 h in 9 month-old (control: 0.61 ± 0.049 g; digest: 0.83 ± 0.059 g) and 24 month-old mice (control: 0.52 ± 0.067 g; digest: 1.01 ± 0.064 g). In summary, we found that novel bioactive peptides, namely, rice-ghretropins, from the enzymatic digest of rice endosperm stimulated acylated ghrelin secretion and increased food intake. This is the first report of rice-derived exogenous bioactive peptides that increase acylated ghrelin secretion.

Multifunctional bioactive properties of hydrolysates from colocynth (Citrullus colocynthis) seeds derived proteins: Characterization and biological properties

Citrullus colocynthis (Colocynth) has gained a great deal of interest in their applications as indigenous nutraceutical and as a functional food ingredient. The intact colocynth seed protein was enzymatically hydrolyzed using proteolytic enzymes (alcalase, bromelain, and chymotrypsin) at different time intervals of 3, 6, and 9 h. The highest degree of hydrolysis (87.82%) was observed in chymotrypsin derived colocynth seed protein hydrolysates (CSPH) for 9 h. The CSPHs was further investigated through in-vitro assay to explore its potential biological activity such as antioxidant, inhibition of enzymatic marker related to diabetes (DPP-IV, α-glucosidase and α-amylase) and hyperlipidaemia (cholesteryl esterase and pancreatic lipase). Chymotrypsin hydrolysate showed the strongest DPPH (65.7 mM TEAC) and ABTS (525.2 mM TEAC) radical scavenging activity after 6 h of hydrolysis. Moreover, chymotrypsin-treated CSPH for 6 h inhibited cholesteryl esterase (IC₅₀ = 13.68 μg/mL) and pancreatic lipase (IC₅₀ = 14.12 μg/mL) significantly when compared to native protein. Whereas, bromelain and alcalase treated hydrolysate for 6 h effectively inhibited α-glucosidase and α-amylase at an inhibitory concentration of IC₅₀ = 13.27 μg/mL and of IC₅₀ = 17 μg/mL. Overall, the findings indicated that protein hydrolysates exhibited superior biological activity than intact colocynth seed proteins isolate (CSPI) and could be a sustainable source of bioactive peptides.

Natural Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors: A Review

PCSK9 (proprotein convertase subtilisin/kexin type 9) is an enzyme that helps to reduce cardiovascular events. This clinical result is attributable primarily to the crucial involvement of PCSK9 in regulating the low-density lipoprotein cholesterol level. Because oral anti-PCSK9 medications have yet to be available, the benefits of this unique treatment approach have been diminished. Identifying naturally occurring PCSK9 inhibitors may lead to considerable progress in this regard. These inhibitors serve as a starting point for producing oral and effective components that could be used with statins to boost the proportion of patients who achieve their LDL-cholesterol goals. In this review, we have briefly summarised the recent information regarding natural components or extracts that have been shown to inhibit PCSK9 activity.

Small-interfering RNA targeting proprotein convertase subtilisin/kexin type 9 might promote fatty liver disease and hepatocellular carcinoma through upregulation of CD36

Proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to low-density lipoprotein (LDL) receptor and fatty acid translocase CD36, inducing lysosomal degradation of these two receptors in the liver cells. Both monoclonal antibody (mAb) and small-interfering RNA (siRNA) targeting PCSK9 have been designed for treatment of familial hypercholesterolemia recently, with elevating LDL receptors on the liver cell surface and increasing LDL uptake as the main beneficial mechanism. However, given that the binding domains of PCSK9 for LDL receptor and CD36 are different, and PCSK9 mAb only attacks the domain for LDL receptor, CD36 expression remains partially controlled under PCSK9 mAb treatment. In contrast, PCSK9 siRNA brings on complete loss of PCSK9, resulting in overexpression of CD36. Based on the fact that CD36 is a key factor in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) and subsequent hepatocellular carcinoma (HCC), the risk of developing NAFLD and HCC on long-term use of PCSK9 siRNA is thus raised as a hypothesis. Additionally, because CD36 is also involved in the promotion of malignant diseases other than HCC, such as acute myeloid leukemia, gastric cancer, breast cancer, and colorectal cancer, the speculative danger of flourishing these malignancies by PCSK9 siRNA is discussed as well.

Purification, Identification and Molecular Docking of Novel Antioxidant Peptides from Walnut (Juglans regia L.) Protein Hydrolysates

Walnut protein isolate (WPI) was hydrolyzed using Alcalase for 0, 30, 60, 90, 120 and 150 min to investigate the effect of different hydrolysis times on the structure and antioxidant properties of walnut proteins. The identified peptides HADMVFY, NHCQYYL, NLFHKRP and PSYQPTP were used to investigate the structure-activity relationship by using LC-MS/MS and molecular docking. The kinetic equations DH = 3.72ln [1 + (6.68 E₀/S₀ + 0.08) t] were developed and validated to explore the mechanism of WIP hydrolysis by Alcalase. Structural characteristics showed that the UV fluorescence intensity and endogenous fluorescence intensity of the hydrolysates were significantly higher than those of the control. FTIR results suggested that the secondary structure gradually shifted from an ordered to a disordered structure. Enzymatic hydrolysis containing much smaller molecule peptides than WPI was observed by molecular weight distribution. In vitro, an antioxidant test indicated that Alcalase protease hydrolysis at 120 min showed more potent antioxidant activity than hydrolysates at other hydrolysis times. In addition, four new antioxidant peptides were identified by LC-MS/MS. Molecular docking indicated that these peptides could interact with ABTS through interactions such as hydrogen bonding and hydrophobic interactions. Thus, WPI hydrolysates could be used as potential antioxidants in the food and pharmaceutical industries.

Modulation of vascular endothelial inflammatory response by proprotein convertase subtilisin-kexin type 9

BACKGROUND AND AIMS

Endotoxins carried within LDL are cleared from the circulation via hepatic LDL receptor (LDLR)-mediated endocytosis. Proprotein convertase subtilisin-kexin type 9 (PCSK9) reduces this clearance by down-regulating LDLR density on hepatocytes. In addition to hepatocytes, vascular endothelial cells also express receptor targets of PCSK9, including LDLR. Therefore, we hypothesized that PCSK9 may regulate vascular endothelial cell uptake of lipopolysaccharide (LPS) and alter the vascular endothelial cell inflammatory response.

METHODS AND RESULTS

We found that LPS is internalized by human umbilical vein vascular endothelial cells (HUVECs) and LPS uptake dose-dependently increased with increasing LDL concentration. Intracellular LPS co-localized with LDL. PCSK9 and, separately, blocking antibodies against LDLR, dose-dependently decreased the vascular endothelial cell uptake of LPS and, furthermore, inhibition of endocytosis using Dynasore blocked LPS uptake. In contrast, blocking antibodies against TLR4 did not alter LPS uptake. PCSK9 decreased the LPS-induced proinflammatory response (IL-6 and IL-8 gene expression and protein secretion, and VCAM-1/ICAM-1 expression) in vascular endothelial cells. In addition, a decrease in PCSK9 and increase in LDLR, mediated by triciribine or siPCSK9, increased LPS uptake and the LPS-induced proinflammatory response. Similar results were also found in aortic vascular tissue from Pcsk9^-/- mice after LPS injection.

CONCLUSIONS

Our data suggest that, similar to PCSK9 treatment in hepatocytes, PCSK9 reduces vascular endothelial cell uptake of LPS via LDLR-mediated endocytosis. Consequently, PCSK9 decreases the LPS-induced proinflammatory response in vascular endothelial cells. These results raise the possibility that PCSK9 inhibition may have additional effects on vascular endothelial inflammation via this alternative pathway, beyond the known effects of PCSK9 inhibition on LDL lowering and hepatic endotoxin clearance.

DPP-IV Inhibitory Peptides GPF, IGL, and GGGW Obtained from Chicken Blood Hydrolysates

Blood is a meat by-product rich in proteins with properties that can be improved after hydrolysis, making it a sustainable alternative for use in the generation of bioactive peptides. The objective of this study was to identify dipeptidyl peptidase IV (DPP-IV) inhibitory peptides obtained from different chicken blood hydrolysates prepared using combinations of four different enzymes. Best results were observed for AP (2% Alcalase + 5% Protana Prime) and APP (2% Alcalase + 5% Protana Prime + 3% Protana UBoost) hydrolysates obtaining inhibition values of 60.55 and 53.61%, respectively, assayed at a concentration of 10 mg/mL. Free amino acids were determined to establish the impact of exopeptidase activity in the samples. A total of 79 and 12 sequences of peptides were identified by liquid chromatography and mass spectrometry in tandem (LC-MS/MS) in AP and APP samples, respectively. Nine of the identified peptides were established as potential DPP-IV inhibitory using in silico approaches and later synthesized for confirmation. Thus, peptides GPF, IGL, and GGGW showed good DPP-IV inhibitory activity with IC₅₀ values of 0.94, 2.22, and 2.73 mM, respectively. This study confirmed the potential of peptides obtained from chicken blood hydrolysates to be used as DPP-IV inhibitors and, therefore, in the control or modulation of type 2 diabetes.

Proprotein Convertase Subtilisin/Kexin 9 (PCSK9) Promotes Macrophage Activation via LDL Receptor-Independent Mechanisms

BACKGROUND

Activated macrophages contribute to the pathogenesis of vascular disease. Vein graft failure is a major clinical problem with limited therapeutic options. PCSK9 (proprotein convertase subtilisin/kexin 9) increases low-density lipoprotein (LDL)-cholesterol levels via LDL receptor (LDLR) degradation. The role of PCSK9 in macrophage activation and vein graft failure is largely unknown, especially through LDLR-independent mechanisms. This study aimed to explore a novel mechanism of macrophage activation and vein graft disease induced by circulating PCSK9 in an LDLR-independent fashion.

METHODS

We used Ldlr^-/- mice to examine the LDLR-independent roles of circulating PCSK9 in experimental vein grafts. Adeno-associated virus (AAV) vector encoding a gain-of-function mutant of PCSK9 (rAAV8/D377Y-mPCSK9) induced hepatic PCSK9 overproduction. To explore novel inflammatory targets of PCSK9, we used systems biology in Ldlr^-/- mouse macrophages.

RESULTS

In Ldlr^-/- mice, AAV-PCSK9 increased circulating PCSK9, but did not change serum cholesterol and triglyceride levels. AAV-PCSK9 promoted vein graft lesion development when compared with control AAV. In vivo molecular imaging revealed that AAV-PCSK9 increased macrophage accumulation and matrix metalloproteinase activity associated with decreased fibrillar collagen, a molecular determinant of atherosclerotic plaque stability. AAV-PCSK9 induced mRNA expression of the pro-inflammatory mediators IL-1β (interleukin-1 beta), TNFα (tumor necrosis factor alpha), and MCP-1 (monocyte chemoattractant protein-1) in peritoneal macrophages underpinned by an in vitro analysis of Ldlr^-/- mouse macrophages stimulated with endotoxin-free recombinant PCSK9. A combination of unbiased global transcriptomics and new network-based hyperedge entanglement prediction analysis identified the NF-κB (nuclear factor-kappa B) signaling molecules, lectin-like oxidized LOX-1 (LDL receptor-1), and SDC4 (syndecan-4) as potential PCSK9 targets mediating pro-inflammatory responses in macrophages.

CONCLUSIONS

Circulating PCSK9 induces macrophage activation and vein graft lesion development via LDLR-independent mechanisms. PCSK9 may be a potential target for pharmacologic treatment for this unmet medical need.

Additive effects of ezetimibe, evolocumab, and alirocumab on plaque burden and lipid content as assessed by intravascular ultrasound: A PRISMA-compliant meta-analysis

BACKGROUND

The additive effects of ezetimibe, evolocumab or alirocumab on lipid level, plaque volume, and plaque composition using intravascular ultrasound (IVUS) remain unclear.

METHODS

According to the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement, we performed a systematic review and meta-analysis of trials assessing the effects of ezetimibe, evolocumab, and alirocumab on coronary atherosclerosis using IVUS. The primary outcome was change in total atheroma volume (TAV), and the secondary outcomes were changes and differences in plaque composition and lipid content.

RESULTS

Data were collected from 9 trials, involving 917 patients who received ezetimibe, evolocumab or alirocumab in addition to a statin and 919 patients who received statins alone. The pooled estimate demonstrated a significant reduction in TAV with the addition of ezetimibe and favorable effects of evolocumab and alirocumab on TAV. Subgroup analysis also supported favorable effects of evolocumab and alirocumab on TAV, according to baseline TAV, gender, type 2 diabetes mellitus, and prior stain use. Addition of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor to statin therapy resulted in significant reductions in low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), and triglycerides (TG), but not in high-density lipoprotein cholesterol (HDL-C). The pooled estimate also showed significant favorable effects of ezetimibe on LDL-C, TC, and TG, but an insignificant effect on HDL-C. Patients who received ezetimibe showed similar changes in the necrotic core, fibro-fatty plaque, fibrous plaque, and dense calcification compared with patients not treated with ezetimibe.

CONCLUSIONS

The addition of ezetimibe to statin therapy may further reduce plaque and lipid burdens but may not modify plaque composition. Although current evidence supports a similar impact from the addition of PCSK9 inhibitors to statin therapy, more evidence is needed to confirm such an effect.

Prognostic Impacts of LL-37 in Relation to Lipid Profiles of Patients with Myocardial Infarction: A Prospective Cohort Study

Background. In vivo studies show that LL-37 inhibits the progression of atherosclerosis and predicts a lower risk of recurrent ischemia in patients with acute myocardial infarction (AMI), which could be mediated by the modulation of lipid metabolism. The current study aimed to investigate the effects of various lipid contents on the prognostic impacts of LL-37 in patients with AMI. Methods. A total of 1567 consecutive AMI patients were prospectively recruited from March 2017 to January 2020. Patients were firstly stratified into two groups by the median level of LL-37 and then stratified by levels of various lipid contents and proprotein convertase subtilisin/kexin type 9 (PCSK9). Cox regression with multiple adjustments was performed to analyze associations between LL-37, lipid profiles, PCSK9, and various outcomes. The primary outcome was major adverse cardiovascular event (MACE), a composite of all-cause death, recurrent MI, and ischemic stroke. Results. During a median follow-up of 786 (726−1107) days, a total of 252 MACEs occurred. A high level of LL-37 was associated with lower risk of MACE in patients with elevated lipoprotein(a) (≥300 mg/L, hazard ratio (HR): 0.49, 95% confidence interval (CI): 0.29−0.86, p = 0.012) or PCSK9 levels above the median (≥47.4 ng/mL, HR: 0.57, 95% CI: 0.39−0.82, p < 0.001), which was not observed for those without elevated lp(a) (<300 mg/L, HR: 0.96, 95% CI: 0.70−1.31, p = 0.781, pinteraction = 0.035) or PCSK9 (<47.4 ng/mL, HR: 1.02, 95% CI: 0.68−1.54, p = 0.905, pinteraction = 0.032). Conclusions. For patients with AMI, a high level of LL-37 was associated with lower ischemic risk among patients with elevated lp(a) and PCSK9.

PCSK9 Inhibition: From Current Advances to Evolving Future

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secretory serine protease synthesized primarily by the liver. It mainly promotes the degradation of low-density lipoprotein receptor (LDL-R) by binding LDL-R, reducing low-density lipoprotein cholesterol (LDL-C) clearance. In addition to regulating LDL-R, PCSK9 inhibitors can also bind Toll-like receptors (TLRs), scavenger receptor B (SR-B/CD36), low-density lipoprotein receptor-related protein 1 (LRP1), apolipoprotein E receptor-2 (ApoER2) and very-low-density lipoprotein receptor (VLDL-R) reducing the lipoprotein concentration and slowing thrombosis. In addition to cardiovascular diseases, PCSK9 is also used in pancreatic cancer, sepsis, and Parkinson’s disease. Currently marketed PCSK9 inhibitors include alirocumab, evolocumab, and inclisiran, as well as small molecules, nucleic acid drugs, and vaccines under development. This review systematically summarized the application, preclinical studies, safety, mechanism of action, and latest research progress of PCSK9 inhibitors, aiming to provide ideas for the drug research and development and the clinical application of PCSK9 in cardiovascular diseases and expand its application in other diseases.

Contemporary National Patterns of Eligibility and Use of Novel Lipid-Lowering Therapies in the United States

Background The emergence of PCSK9i (proprotein convertase subtilisin kexin type 9 inhibitor) and icosapent ethyl (IPE) has expanded the role of lipid-lowering therapies beyond statins. Despite recommendations by clinical practice guidelines, their national eligibility and use rates remain unclear. Methods and Results In the National Health and Nutrition Examination Survey data from 2017 to 2020, we assessed eligibility and the use of statins, PCSK9i, and IPE among US adults according to American College of Cardiology/American Heart Association guideline recommendations. Eligibility for PCSK9i and IPE were determined in the following 2 scenarios: (1) assuming existing lipid-lowering therapy as the maximum tolerated before assessing eligibility for novel therapies and (2) assessing eligibility after assuming initiation and maximal escalation of preexisting lipid-lowering therapies and accounting for expected lipid improvements. Of 2729 sampled individuals, representing 149.3 million adults, 1376 had indications for statins, representing 65.8 million or 44.0% (95% CI, 40.9%-47.2%) of adults. Current statin use was 45% of those eligible and was low across demographic groups. A total of 9.7 and 11.6 million adults would benefit from PCSK9i and IPE, respectively, based on lipid profiles and existing therapies. Assuming maximal escalation of statins and addition of ezetimibe, 4.1% (95% CI, 2.8%-5.4%) of adults or 6.1 million would benefit from PCSK9i and 6.8% (95% CI, 5.4%-8.3%) or 10.2 million from IPE. Conclusions Six and 10 million individuals have clinical profiles whereby PCSK9i and IPE, respectively, would be expected to improve cardiovascular outcomes even after maximum escalation of statins and ezetimibe use, but remain undertreated with lipid-lowering therapies. Optimal use of lipid-targeted agents that include these novel agents is needed to improve population health outcomes.

Reduction of C-reactive protein, low-density lipoprotein cholesterol, and its relationship with cardiovascular events of different lipid-lowering therapies: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

To evaluate the reductions of C-reactive protein (CRP) and low-density lipoprotein cholesterol (LDL-C) in different lipid-lowering drugs, and to assess the relationships between the reductions of CRP, LDL-C, and cardiovascular (CV) events.

METHODS

We searched MEDLINE, EMBASE, and Cochrane CENTRAL up to September 1, 2021. Randomized controlled trials (RCTs) comparing statins, proprotein convertase subtilisin/kexin type 9 monoclonal antibodies (PCSK9-mAbs), or ezetimibe against placebo with a treatment duration of at least 4 weeks and data on the effects of cholesterol-lowering interventions on LDL-C and CRP were included in this meta-analysis. The weighted mean difference (WMD) and 95% confidence interval (CI) were calculated.

RESULTS

Compared with placebo treatment, statins and ezetimibe treatments resulted in a significant decrease in LDL-C level (statins: WMD -47.94 mg/dL, 95% CI -51.21 to -44.67 mg/dL; ezetimibe: WMD -22.84 mg/dL, 95% CI -26.76 to -18.92 mg/dL) and CRP level (statins: WMD -0.67 mg/L, 95% CI -0.90 to -0.45 mg/dL; ezetimibe: -0.64 mg/L, 95% CI -1.07 to -0.21 mg/dL). Compared with placebo treatment, treatment with PCSK9-mAbs resulted in significant decrease in LDL-C level (WMD -54.24 mg/dL, 95% CI -59.77 to -48.70 mg/dL), while the concentration of CRP did not decrease significantly. Meta-regression analysis showed no significant association between change in CRP level and change in LDL-C level. Subgroup comparisons suggested that treatment with PCSK9-mAbs showed a greater reduction in LDL-C level when compared with the statins group and ezetimibe group, while the risks of CV death, myocardial infarction (MI), and stroke showed no significant differences.

CONCLUSION

Based on the current study, our results suggested that statins, ezetimibe, and PCSK9-mAbs are effective in reducing LDL-C levels. Treatment with statins and ezetimibe also demonstrated a significant effect on CRP. The traditional lipid-lowering strategy including statin and ezetimibe showed similar benefit on CV outcomes compared with the PCSK9-mAbs treatment.

PCSK9 is minimally associated with HDL but impairs the anti-atherosclerotic HDL effects on endothelial cell activation

Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) regulates the cell-surface localization of LDL receptors in hepatocytes and is associated with LDL and lipoprotein(a) [Lp(a)] uptake, reducing blood concentrations. However, the connection between PCSK9 and HDL is unclear. Here, we investigated the association of plasma PCSK9 with HDL subpopulations and examined the effects of PCSK9 on the atheroprotective function of HDL. We examined the association of PCSK9 with HDL in apoB-depleted plasma by ELISA, native PAGE, and immunoblotting. Our analyses showed that upon apoB-depletion, total circulating PCSK9 levels were 32% of those observed in normolipidemic plasma, and only 6% of PCSK9 in the apoB-depleted plasma, including both the mature and furin-cleaved forms, was associated with HDL. We also show human recombinant PCSK9 abolished the capacity of reconstituted HDL to reduce the formation of ROS in endothelial cells, while a PCSK9-blocking antibody enhanced the capacity of human HDL (in apoB-depleted plasma) to reduce ROS formation in endothelial cells and promote endothelial cell migration. Overall, our findings suggest that PCSK9 is only minimally associated with HDL particles, but PCSK9 in apoB-depleted plasma can affect the atheroprotective properties of HDL related to preservation of endothelial function. This study contributes to the elucidation of the pathophysiological role of plasma PCSK9 and highlights further the anti-atherosclerotic effect of PCSK9 inhibition.