Proprotein Convertase Research Articles

Associations of Lipid-Lowering Drugs With Blood Pressure and Fasting Glucose: A Mendelian Randomization Study.

Observational studies have linked LDL-C (low-density lipoprotein-cholesterol)-lowering drugs with lower blood pressure (BP) and higher fasting glucose, but the causality remains unclear. We conducted a drug target Mendelian randomization study to assess the causal associations of genetically proxied inhibition of HMGCR (3-hydroxy-3-methylglutaryl coenzyme A reductase), PCSK9 (proprotein convertase subtilisin/kexin type 9), and NPC1L1 (Niemann-Pick C1-Like 1) with BP and fasting glucose. Single-nucleotide polymorphisms in HMGCR, NPC1L1, and PCSK9 associated with LDL-C in a genome-wide association study meta-analysis from the Global Lipid Genetics Consortium (173 082 European individuals) were used to proxy LDL-C-lowering drug targets. BP and fasting glucose data were obtained from genome-wide association studies conducted by the International Consortium of Blood Pressure (757 601 European participants) and the Glucose and Insulin-related Traits Consortium (58 074 European participants). We used the inverse-variance weighted method and a series of sensitivity analyses for assessment. Genetically proxied inhibition of HMGCR was negatively associated with systolic BP (β, -0.81 [95% CI, -1.26 to -0.37 mm Hg]; P=3.72×10-4) and diastolic BP (β, -1.58 [95% CI, -2.24 to -0.91 mm Hg]; P=3.23×10-6). Conversely, we observed a positive association between genetically proxied inhibition of HMGCR and high fasting glucose (β, 0.13 [95% CI, 0.08-0.17 mmol/L]; P=4.25×10-8). However, there was no association of PCSK9 and NPC1L1 inhibition with BP or fasting glucose. Genetically proxied inhibition of HMGCR was significantly associated with low BP and high fasting glucose, while there was no effect of PCSK9 and NPC1L1 inhibition on BP or fasting glucose.

Perioperative pembrolizumab in early-stage non-small cell lung cancer (NSCLC): safety, efficacy, and exploratory biomarker analysis

BackgroundOur study was designed to determine the safety, efficacy, and immunological effects of perioperative pembrolizumab in early-stage NSCLC.MethodsThis is a single-arm phase II study of perioperative pembrolizumab in patients with...

Conditional knockdown of hepatic PCSK9 ameliorates high-fat diet-induced liver inflammation in mice

InstructionAccumulating evidence has shown that proprotein convertase subtilisin/kexin type 9 (PCSK9) is associated with inflammation in the vascular system. However, the roles of PCSK9 in hepatic inflammation remain unclear. Because PCSK9 is mainly expressed in the liver and modulates lipid uptake through low-density lipoprotein receptor family members, the present study aimed to elucidate the effect of conditional knockdown of hepatic PCSK9 on hyperlipidemia-induced inflammation and the underlying mechanisms of action.MethodsPCSK9flox/flox mice were bred with ALB-Cre+ mice to obtain hepatic PCSK9(−/−), PCSK9(+/−), and PCSK9(+/+) mice. These mice were fed with a high-fat diet for 9 weeks to induce inflammation. The effects of conditional knockdown of hepatic PCSK9 on inflammation and the underlying mechanisms were investigated by molecular biological techniques. Moreover, the findings were verified in vitro using HepG2 cells.Results and DiscussionConditional knockdown of hepatic PCSK9 remarkably decreased plasma levels of total cholesterol and alleviated hyperlipidemia-induced liver injury. Mechanistically, conditional knockdown of hepatic PCSK9 significantly reduced the levels of pro-inflammatory factors by downregulating the expression of Toll-like receptors, mitogen-activated protein kinase (MAPK), and phosphoinositide-3 kinase/protein kinase B, which subsequently attenuated the expression of downstream molecules, namely nuclear factor kappa-B and activator protein-1. The related mechanisms were confirmed using lipid-loaded HepG2 cells together with PCSK9 siRNA, alirocumab (anti-PCSK9 antibody), and/or a p38-MAPK inhibitor. These findings confirmed that conditional knockdown of hepatic PCSK9 attenuates liver inflammation following hyperlipidemia induction by modulating multiple signaling pathways; this suggests that targeting PCSK9 knockdown/inhibition with appropriate agents is useful not only for treating hyperlipidemia but also for ameliorating hyperlipidemia-induced liver inflammation.

Pathogenic Deep Intronic PCSK1 Variant Causes Proprotein Convertase 1/3 Deficiency in a Family.

Proprotein convertase 1/3 (PC1/3), encoded by PCSK1, is expressed in neuronal and endocrine cell types, where it activates a number of protein precursors that play roles in energy homeostasis. Biallelic PCSK1 loss-of-function mutations cause a polyendocrinopathy; a total of 34 patients were reported. An infant with congenital malabsorptive diarrhea of all carbohydrates underwent exome sequencing (ES), with particular consideration of PC1/3 deficiency, but no mutations were found. The onset of obesity in the second year of life increased suspicion of PC1/3 deficiency in the proband, as well as in his equally affected cousin. Transcript analysis revealed minor amounts of an aberrant PCSK1 transcript containing intron 9 sequence and encoding a premature stop codon (p.Pro400Valfs*35). A deep intronic PCSK1 variant, NG_021161.1(NM_000439.5):c.1196+2681T>A, was found to segregate in the proband's family with the disease. A minigene approach demonstrated that the identified deep-intronic variant underlies pseudo-exon inclusion of the intron 9 sequence in the transcript. The characteristic phenotype of PC1/3 deficiency might require extended genetic testing to make a timely diagnosis.

Mechanisms underlying the effects of the conditional knockdown of hepatic PCSK9 in attenuating lipopolysaccharide-induced acute liver inflammation.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is known to promote hyperlipidemia primarily by inducing the degradation of the low-density lipoprotein receptor. Notably, recent studies have demonstrated that PCSK9 promotes inflammation in the vascular system, however, the roles of PCSK9 in hepatic inflammation remain unclear. As PCSK9 is primarily expressed in the liver, this study aimed to elucidate the roles of PCSK9 and the underlying mechanisms in lipopolysaccharide (LPS)-challenged hepatocytes. Next-generation sequencing analysis revealed that the conditional knockdown of hepatic PCSK9 significantly reduced the plasma levels of total cholesterol and modulated the expression of hundreds of genes. Importantly, PCSK9 knockdown attenuated hepatic inflammation by suppressing several signaling pathways related to inflammation, including the Toll-like receptor, mitogen-activated protein kinase (MAPK), and phosphoinositide-3 kinase/protein kinase B pathways. This subsequently altered the expression of nuclear factor kappa-B and activator protein 1. The underlying mechanisms were further confirmed by in vitro studies using primary hepatocytes and HepG2 cells, with a p38-MAPK inhibitor, a PCSK9 antibody, and two siRNAs against PCSK9. This study is the first to report that hepatic PCSK9 knockdown ameliorates LPS-induced acute liver inflammation via modulating multiple signaling pathways, thereby suggesting therapeutic potential of PCSK9 inhibitors in treating diseases related to hepatic inflammation.

Lipid Profile, PCSK9, ANGPTL3 and Lipoprotein (a) Levels in Men Diagnosed With Localized High-Grade Prostate Cancer and Men At-Risk of Prostate Cancer.

Some cancers have been found to require abundant supplies of lipids for their development. One example is prostate cancer (PCa). To date, lipid-modifying factors, such as proprotein convertase subtilisin/kexin type 9 (PCSK9), angiopoietin-like 3 protein (ANGPTL3), and lipoprotein(a) or Lp(a), have not been reported in men with PCa. The present study aimed to verify whether plasma levels of these lipid-related proteins vary in men with PCa compared to at-risk but cancer-free men. Plasma samples from 35 men with locally advanced PCa Gleason 8 and 9 versus 35 men at risk of PCa were selected as cases and controls. Blood samples were paired according to age and BMI. Apolipoprotein B100 (Apo B), Lp(a), and lipid profiles were measured on an analytical platform (Roche Cobas). PCSK9 and ANGPTL3 levels were determined by ELISA. No significant change in lipids and related factors levels was observed between men with localized PCa Gleason 8 or 9 and matched controls. A correlation between ANGPTL3 and HDL levels was only confirmed in controls (ρ = 0.54, p = 0.0009). PCSK9 was inversely associated with PSA levels in the entire cohort (ρ = -0.31, p < 0.01), suggesting that factors influencing PCSK9 could also influence PSA levels. In controls only, PSA levels were correlated with LDL, Apo B, non-HDL, total cholesterol, and triglycerides (all ρ coefficients ≥ 0.35, all p-values < 0.05). PCSK9 was correlated to LDL in PCa men, but the relationship was unexpectedly found to be inverse. In this observational study, lipid profiles, PCSK9, ANGPTL3, and Lp(a) levels did not change in men diagnosed with locally advanced Gleason 8 or 9 PCa compared to at-risk but cancer-free men. The present data suggest a complex interplay between PCSK9, PSA, and the lipid profile in localized PCa.

Embelin Elevates Endoplasmic Reticulum Calcium Levels and Blocks the Sterol Regulatory Element-Binding Protein 2 Mediated Proprotein Convertase Subtilisin/Kexin Type 9 Expression and Improves the Low-Density Lipoprotein Receptor Mediated Lipid Clearance on Hepatocytes.

Cardiovascular diseases (CVDs) continue to be one of the leading causes of morbidity and mortality worldwide, with a significant increase in recent years. Atherosclerosis, the pathological basis and prime reason for CVDs is primarily driven by dysregulated lipid metabolism and inflammation. Recently, proprotein convertase subtilisin kexin9 (PCSK9) has been evolved to be highly implicated in the circulatory low-density lipoprotein cholesterol levels by its modulatory effects on the low-density lipoprotein receptor (LDLR) mediated clearance. Even though not economical, the therapies targeting PCSK9 demonstrated appreciable levels of efficiency in managing hyperlipidaemic conditions. Embelin (2,5-dihydroxy-3-undecyl-1,4-benzoquinone) is a naturally occurring para-benzoquinone isolated from dried berries of Embelia ribes, which possess several effects in maintaining the cholesterol homeostasis. In this study, we have analysed the role of embelin in sterol regulatory element-binding protein 2 (SREBP2) mediated PCSK9 expression in cultured hepatocytes. The study showed that the embelin treatment attenuates the endoplasmic reticulum (ER) stress-induced reactive oxygen species levels and ER stress markers on cultured hepatocytes. The treatment of embelin modulates the mRNA and protein level expression of SREBP2 and its downstream targets like PCSK9, LDLR, and HMG-CoA reductase (HMGCR). Interestingly the Ca2+ levels and the calcium binding protein of ER were significantly increased with embelin treatment. The work revealed a putative mechanism of embelin in lowering PCSK9 levels by boosting ER Ca2+ levels, thereby blocking SREBP2 nuclear translocation. Further, this reduces LDLR degradation and increases receptor-mediated circulatory lipid clearance. The study summarized the potential clinical applications of embelin in addressing the cardio vascular diseases.

Impact of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors onLipoprotein(a): A Meta-Analysis and Meta-Regression of Randomized Controlled Trials.

Lipoprotein(a) [Lp(a)] has been independently associated with increased cardiovascular risk. The authors examined the effect of monoclonal antibody proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9is) on plasma Lp(a) levels across multiple trials. Studies were retrieved comparing the effect of PCSK9i vs placebo on Lp(a) levels. The primary outcome was percent change in Lp(a) levels. Factors associated with the treatment effect were determined by meta-regression analysis. Subgroup analyses were done to explore potential treatment effect differences. PCSK9i reduced Lp(a) levels on average of-27% (95%CI:-29.8% to-24.1%, P<0.001). Factors associated with the treatment effect included mean percent change in low-density lipoprotein cholesterol (P=0.003, beta coefficient 0.34, 95%CI: 0.11-0.57, tau2=94.8, R2=11.82) and apolipoprotein B (P<0.002, beta coefficient 0.4, 95%CI: 0.14-0.64, tau2=93.68, R2=11.86). Subgroup analyses revealed consistent treatment effect amongst comparators vs placebo:-27.69% (95%CI:-30.85% to-24.54%, P<0.001), vs ezetimibe:-24.0% (95%CI:-29.95% to-18.01%, P<0.001), type of PCSK9i, evolocumab:-29.35% (95%CI:-33.56% to-25.14%, P<0.001) vs alirocumab:-24.50% (95%CI:-27.96% to-21.04%, P<0.001), and presence of familial hypercholesterolemia:-25.63% (95%CI:-31.96% to-19.30%, P<0.001 vs no familial hypercholesterolemia:-27.22%; 95%CI:-30.34% to-24.09%, P<0.001). Varying treatment effects were noted in the duration of treatment (12weeks or shorter:-32.43% [95%CI:-36.63% to-28.23% vs >12weeks:-22.31%] [95%CI:-25.13% to-19.49%, P<0.001]), P interaction< 0.01. PCSK9is reduce Lp(a) levels by an average of 27%. Mean percent change in low-density lipoprotein cholesterol and apolipoprotein B were associated with treatment effect.

A Medical Claims Database Study of Factors Associated with Medication Adherence and Treatment Persistence in Patients Receiving PCSK9 Monoclonal Antibodies

To investigate medication adherence and treatment persistence in patients receiving proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibodies (mAbs) in Japan. Using an anonymized claims database from January 2015 to December 2021, data on adult patients at high risk for atherosclerotic cardiovascular disease or with a history of coronary artery disease (CAD) who had at least 1 prescription for PCSK9-mAbs were retrieved. In total, 276 patients were analyzed. The cumulative treatment persistence rate after 1 year was 67.0%. A multivariate analysis revealed that better adherence to oral low-density lipoprotein cholesterol (LDL-C)-lowering therapy in the year before starting PCSK9-mAbs (adjusted odds ratio [OR] 2.16) and a history of CAD for secondary prevention (adjusted OR 2.44) were associated with better adherence to PCSK9-mAbs in the first year. Better adherence to oral LDL-C-lowering therapy in the year before starting PCSK9-mAbs (adjusted OR 2.32) and a history of CAD for secondary prevention (adjusted OR 3.03) were also associated with a lower rate of discontinuation of PCSK9-mAbs. Age, sex, comorbidity, number of tablets taken daily (all medications), and number of hospital or clinic visits in the year prior to starting PCSK9-mAbs did not affect the persistence rate or adherence to PCSK9-mAbs in the multivariate analyses. Better adherence to oral LDL-C-lowering therapy and secondary prevention were identified as factors associated with better medication adherence and treatment persistence in patients receiving PCSK9-mAbs within the first year.

Targeting PCSK9, through an innovative cVLP-based vaccine, enhanced the therapeutic activity of a cVLP-HER2 vaccine in a preclinical model of HER2-positive mammary carcinoma.

HER2-targeted therapies have revolutionized the treatment of HER2-positive breast cancer patients, leading to significant improvements in tumor response rates and survival. However, resistance and incomplete response remain considerable challenges. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition is a novel therapeutic strategy for the management of dyslipidemia by enhancing the clearance of low-density lipoprotein cholesterol receptors, however recent evidence also shows links between PCSK9 and cancer cells. We present an innovative immunization approach combining capsid virus-like particle (cVLP)-based vaccines against HER2 and PCSK9. The therapeutic activity of the combined vaccine was evaluated in female mice challenged with HER2-positive mammary carcinoma cells. Controls included untreated mice and mice treated with cVLP-PCSK9 and cVLP-HER2 as standalone therapies. Antibodies elicited by vaccinations were detected through ELISA immunoassay. The functional activity of the antibodies was tested in 3D-soft agar assay on human HER2 + + + trastuzumab sensitive and resistant cells. Mice vaccinated with cVLP-HER2 + cVLP-PCSK9 displayed tumor regression from the 40th day after cell challenge in 100% of mice remaining tumor-free even 4months later. In contrast, 83% of mice treated with cVLP-HER2 vaccine alone experienced an initial tumor regression, followed by tumor relapse in 60% of subjects. Untreated mice and mice treated with the cVLP-PCSK9 vaccine alone developed progressive tumors within 1-2months after cell injection. The combined vaccine approach elicited strong anti-human HER2 antibody responses (reaching 1-2mg/ml range) comprising multiple immunoglobulins isotypes. cVLP-PCSK9 vaccine elicited anti-PCSK9 antibody responses, resulting in a marked reduction in PCSK9 serum levels. Although the anti-PCSK9 response was reduced when co-administered with cVLP-HER2, it remained significant. Moreover, both cVLP-HER2 + cVLP-PCSK9 and cVLP-HER2 alone induced anti-HER2 antibodies able to inhibit the 3D growth of human HER2 + + + BT-474 and trastuzumab-resistant BT-474 C5 cells. Strikingly, antibodies elicited by the combined vaccination were more effective than those elicited by the cVLP-HER2 vaccine alone in the inhibition of trastuzumab-resistant C5 cells. The results indicate that cVLP-PCSK9 vaccination shows adjuvant activity when combined with cVLP-HER2 vaccine, enhancing its therapeutic efficacy against HER2-positive breast cancer and holding promise in overcoming the challenges posed by resistance and incomplete responses to HER2-targeted therapy.

Lowering LDL cholesterol by PCSK9 inhibition: a new era of gene silencing, RNA, and alternative therapies.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) discovery has added a new paradigm to our understanding of cholesterol homeostasis and lipid metabolism. Since its discovery, PCSK9 inhibitors have become a widely investigated therapeutic class for lipid management in cardiovascular diseases and hypercholesterolemia. Scientists have explored different approaches for PCSK9 inhibition, such as monoclonal antibodies (mAbs), gene silencing and gene editing techniques, vaccines, mimetic peptides, and small molecules. European Medicines Agency (EMA) and United States Food and Drug Administration (US FDA) have approved only three PCSK9 inhibitors, including two monoclonal antibodies and one small interfering ribonucleic acid (siRNA). Despite the efficacy of approved large molecules, high costs and the need for regular injection have limited their adherence to the patient. This review aims to provide an understanding of PCSK9's function in Low-Density Lipoprotein Cholesterol (LDL-C) management, its current treatment, recent advancements, and potential future development of small molecules in the class of PCSK9 inhibitors.

Isolation of PCSK9-specific nanobodies from synthetic libraries using a combined protein selection strategy

Nanobodies (Nbs) hold great potential to replace conventional antibodies in various biomedical applications. However, conventional methods for their discovery can be time-consuming and expensive. We have developed a reliable protein selection strategy that combines magnetic activated cell sorting (MACS)-based screening of yeast surface display (YSD) libraries and functional ligand-binding identification by Tat-based recognition of associating proteins (FLI-TRAP) to isolate antigen-specific Nbs from synthetic libraries. This combined process enabled isolation of three unique Nb clones (NbT15, NbT21, and NbT22) that all bound specifically to a target antigen, namely proprotein convertase subtilisin/kexin type 9 (PCSK9) as well as a gain-of-function PCSK9 mutant (D374Y). All three clones bound to PCSK9 and blocked the interaction between the low-density lipoprotein receptor (LDLR) and either wild-type PCSK9 or the D374Y mutant. Overall, our combined protein selection method enables rapid and straightforward identification of potent antigen-specific Nbs in a manner that can be executed in a basic laboratory setting without the need for specialized equipment. We anticipate that our strategy will be a valuable addition to the protein engineering toolkit, allowing development of Nbs or virtually any other synthetic binding protein for a wide range of applications.

Molecular Therapeutics in Development to Treat Hyperlipoproteinemia.

Clinical endpoints caused by hyperlipoproteinemia include atherosclerotic cardiovascular disease and acute pancreatitis. Emerging lipid-lowering therapies targeting proprotein convertase subtilisin/kexin 9 (PCSK9), lipoprotein(a), apolipoprotein C-III, and angiopoietin-like protein 3 represent promising advances in the management of patients with hyperlipoproteinemia. These therapies offer novel approaches for lowering pathogenic lipid and lipoprotein species, particularly in patients with serious perturbations who are not adequately controlled with conventional treatments or who are unable to tolerate them. Molecular targets for these novel therapeutic agents were identified and validated through genetic epidemiology studies. Proprotein convertase subtilisin/kexin 9 inhibitors (e.g., monoclonal antibodies and small interfering RNA) have revolutionized hypercholesterolemia management by significantly reducing both low-density lipoproteincholesterol levels and major cardiovascular events. Genome editing of PCSK9 promises to provide a potential cure for patients with familial hypercholesterolemia. Several investigational lipoprotein(a)-targeting therapies aim to reduce the risk of atherosclerotic cardiovascular disease and aortic valve disease, although definitive clinical endpoint studies remain to be completed. Inhibition of APOC3 messenger RNA expression by olezarsen and plozasiran significantly lowers plasma triglyceride levels and markedly reduces pancreatitis risk in patients with familial chylomicronemia syndrome. Finally, angiopoietin-like protein 3 inhibition by the monoclonal antibody evinacumab has transformed management of patients with homozygous familial hypercholesterolemia. Together, these novel agents expand the therapeutic cache, offering personalized lipid-lowering strategies for high-risk patients with hyperlipoproteinemia, improving clinical outcomes and addressing previously unmet medical needs.

Lipid-Lowering Efficiency and Safety of Alirocumab 300 mg Using a 2-mL Autoinjector Device in Real-World Practice: The MARS Study.

Alirocumab is a fully human monoclonal antibody to proprotein convertase subtilisin kexin type 9 used for the reduction of low-density lipoprotein cholesterol (LDL-C) in high-risk patients not reaching their LDL-C target. Recently, a 2-mL prefilled autoinjector has been developed to support the monthly 300-mg dosing regimen with a single-injection administration. Monthly application of 300 mg AlirRocumab (Praluent®) using the 2-mL SYDNEY Device (MARS) is a non-interventional, open, prospective, multi-center cohort study conducted in Germany between 2021 and 2023 with an observational period of 12 weeks. Patients included had primary hypercholesterolemia (heterozygous familial or non-familial) or mixed dyslipidemia and confirmed vascular disease and other risk factors or confirmed familial heterozygous hypercholesterolemia. Primary objectives were to assess the effectiveness of the 2-mL SYDNEY autoinjector measured by the lipid-lowering effect of alirocumab and to document therapy satisfaction, patient adherence, and persistence. Secondary objectives were to assess safety (adverse events) and tolerability. A total of 146 patients were analyzed: 110 (75.3%) patients were proprotein convertase subtilisin kexin type 9 inhibitor naïve and 36 (24.7%) were pre-treated with a proprotein convertase subtilisin kexin type 9 inhibitor. Patient mean age was 65.6 years with a preponderance of male gender (59.6%). At 12 weeks, the LDL-C value had decreased by a median of 59.5 mg/dL (1.5 mmol/L) in naïve patients (median relative decrease: -52.0%). In the pre-treated group, the LDL-C value remained mainly unchanged (median slight numerical relative increase: 1.6%). Treatment satisfaction was rated similarly in both groups with most patients being satisfied/very satisfied and rating the injection as effective, safe, and easy to handle. Twenty-three adverse events in 13 patients (8.0%) were documented. Three patients experienced one serious adverse event each; for five patients, an adverse drug reaction was observed, although none was serious. The occurrence of adverse events was similar in both groups. Alirocumab 300 mg administered with the 2-mL SYDNEY autoinjector was safe and effective in lowering LDL-C after 12 weeks in a routine clinical setting in Germany. The treatment schedule was perceived to be beneficial with excellent device acceptance and satisfaction, potentially increasing patient adherence. Clinicaltrials.gov: NCT05129241.

PCSK9 Expression in Vascular Smooth Muscle Cells: Role of Insulin Resistance and High Glucose

Beyond the regulation of cholesterol metabolism, a number of extrahepatic functions of proprotein convertase subtilisin/kexin type 9 (PCSK9) have been increasingly identified. The main purpose of this study was to verify whether PCSK9 expression in vascular smooth muscle cells (VSMC) is influenced by insulin resistance and high glucose (HG). In cultured rat aortic VSMC from lean insulin-sensitive Zucker rats (LZRs) and obese insulin-resistant Zucker rats (OZRs), a classical animal model of insulin resistance, we evaluated PCSK9 expression with or without the monoclonal antibodies against PCSK9 Alirocumab and Evolocumab or the synthetic PCSK9-binding peptide PEP 2-8. Effects and molecular mechanisms underlying altered PCSK9 expression were evaluated by proliferation and migration assay, reactive oxygen species (ROS) production, and involvement of PKC, NADPH-oxidase, MAPK/ERK-1/2 pathway activation. As a result, we found that, in comparison with LZR, VSMC from OZR showed basal PCSK9 overexpression mitigated by Alirocumab, Evolocumab, PEP 2-8, and the inhibitors of PKC, NADPH-oxidase, and MAPK. The finding of PCSK9 upregulation in VSMC from OZR paralleled with increased ROS production, proliferation, and migration. HG increased PCSK9 expression in VSMC from LZR, but not in OZR, via oxidative stress and with effects reduced by PCSK9 inhibitors. These findings suggest that a dysregulation of PCSK9 in VSMC could be involved in vascular damage in metabolic disorders, such as obesity and diabetes.

Regression of carotid atherosclerosis in high-risk individuals with proprotein convertase subtilisin/kexin type 9 inhibitors.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors represent a novel approach for reducing cholesterol and, accordingly, the burden of atherosclerosis. However, limited data are available regarding the possible effects of PCSK9 inhibitors on atherosclerotic plaque. To evaluate the efficacy of PCSK9 inhibitors in reducing carotid plaque progression in individuals with high-risk carotid atherosclerotic disease. We used carotid total plaque area (TPA) to assess the burden of atherosclerosis. Ultrasound imaging of the carotid was acquired before and after the initiation of PCSK9 inhibitor therapy. We selected high-risk cases with atherosclerosis with a minimum of three ultrasound examinations, 1 year before, one at the time of initiation of a PCSK9 inhibitor, and 1 year after initiating a PCSK9 inhibitor. Statistical analysis was conducted using the mixed-effects model with Restricted Maximum Likelihood (REML). We reviewed data from 131 patients with a mean follow-up of 6 (±4) years. Patients were high-risk, with the majority having diabetes or hypertension. There was a decrease in TPA, particularly during the first 3 years after initiating PCSK9 inhibitor therapy (p < 0.05). Furthermore, we observed that individuals with higher baseline serum low-density lipoprotein cholesterol (LDL-C) levels experienced a greater decline in TPA (p < 0.05). PCSK9 inhibitors are effective in achieving plaque regression in high-risk patients with atherosclerosis. This is important, as plaque regression is associated with a lower risk of stroke, myocardial infarction, or vascular death.

Mutual mediation effects of homocysteine and PCSK9 on coronary lesion severity in patients with acute coronary syndrome: interplay with inflammatory and lipid markers

BackgroundHomocysteine (Hcy) and the proprotein convertase subtilisin/kexin type 9 (PCSK9) significantly contribute to atherosclerosis (AS) as well as coronary lesion severity. Our previous work demonstrated that Hcy upregulates PCSK9, accelerating lipid accumulation and AS. A PCSK9 antagonist reduces plasma Hcy levels in ApoE−/− mice. These findings suggest complex roles for both Hcy and PCSK9 in AS. This study investigated the mutual mediating influence of Hcy together with PCSK9 on coronary lesion severity among individuals diagnosed with acute coronary syndrome (ACS), focusing on their interplay with inflammatory and lipid-related markers.MethodsThis cross-sectional study encompassed 617 individuals diagnosed with ACS. Baseline characteristics, including inflammatory and lipid-related markers, were compared between individuals with non-severe (SYNTAX score ≤ 22) and severe (SYNTAX score > 22) coronary lesions. To evaluate both the impacts of Hcy and PCSK9 on coronary lesions severity, multivariate logistic regression along with mediation analyses were utilized. The robustness of the findings was validated by conducting subgroup analyses and sensitivity tests.ResultsPatients with severe conditions showed higher levels of Hcy, PCSK9, and inflammatory markers compared to non-severe cases. Both Hcy and PCSK9 levels were independently linked to a heightened risk of severe coronary lesions(ORs: 1.03–1.04 and 1.01–1.02, respectively, all P < 0.001). PCSK9 mediated 34.04% of Hcy’s effect on coronary lesion severity, whereas Hcy mediated 31.39% of PCSK9’s effect, indicating significant mutual mediation between these biomarkers. Subgroup analyses revealed consistent associations, with notable interactions based on creatinine levels for Hcy and gender, smoking status, and diagnosis for PCSK9. Sensitivity analyses confirmed the robustness of the mediation effects.ConclusionsThese findings emphasize the mutual mediating effects of Hcy and PCSK9 on coronary lesion severity in patients suffering from ACS. These results highlight the complex interactions between lipid metabolism and inflammation in the pathophysiology of ACS, suggesting that targeting both Hcy and PCSK9 may offer novel therapeutic strategies to mitigate severe coronary lesions among high-risk patients.

PCSK9-antibodies fail to block PCSK9-induced inflammation in macrophages and cannot recapitulate protective effects of PCSK9-deficiency in experimental myocardial infarction.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a crucial role in cholesterol homeostasis by regulating low-density lipoprotein (LDL) receptor levels. Despite its known effects on cholesterol metabolism, the role of PCSK9 in cardiac function, especially post-myocardial infarction (MI), remains unclear. This study investigates the impact of PCSK9 on heart function post-MI and evaluates the effects of PCSK9 inhibition via Alirocumab. We used PCSK9 knockout (KO) mice and wildtype (WT) mice and in vivo treatment with Alirocumab to analyze cardiac function and survival post-MI induced by permanent ligation of the left anterior descending artery. PCSK9 and LDL receptor levels were measured using ELISA and qRT-PCR. Cardiac function was assessed via echocardiography and isolated working heart model experiments. Gene expression changes were evaluated using RNA sequencing, and inflammatory responses in bone marrow-derived macrophages (BMDMs) were analyzed in vitro. PCSK9 was expressed in murine heart tissue at levels comparable to the liver, despite minimal heart RNA expression. PCSK9 KO mice had lower plasma cholesterol levels and showed reduced cardiac functions in the working heart model compared to WT mice. Post-MI, PCSK9 KO mice demonstrated significantly improved survival and reduced ventricular rupture compared to WT mice. Alirocumab treatment, while effective in lowering plasma cholesterol, did not replicate the survival benefits seen in PCSK9 KO mice and even worsened cardiac function post-MI. In vitro, PCSK9 induced significant inflammatory responses in macrophages, which were not mitigated by Alirocumab. PCSK9 accumulation in the heart post-MI contributes to adverse cardiac remodeling and inflammation. Genetic deletion of PCSK9 confers protection against post-infarct mortality, whereas pharmacological inhibition with Alirocumab fails to reproduce these benefits and may exacerbate cardiac dysfunction. These findings highlight the complex role of PCSK9 in cardiac pathology and caution against the assumption that PCSK9 inhibitors will necessarily yield cardiovascular benefits similar to genetic PCSK9 deficiency.

Evaluating the role of PCSK9 inhibitors in reducing cardiovascular events among statin-intolerant patients: a systematic review and meta-analysis

Objective: To assess the efficacy and safety of Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) inhibitors in reducing major adverse cardiovascular events (MACE) in statin-intolerant patients, focusing on low-density lipoprotein cholesterol (LDL-C) reduction and cardiovascular outcomes. Methods: A systematic review and meta-analysis were conducted according to the PRISMA guidelines. Randomised control trails (RCTs) and observational studies from PubMed, Cochrane Library, and Web of Science databases were included. Independent reviewers extracted the data, and the analyses were performed using fixed- and random-effects models. Heterogeneity was evaluated using the I2 statistic and publication bias was assessed using Egger’s test. Results: Fifteen studies involving 69–18 924 participants were included. PCSK9 inhibitors reduced LDL-C levels by 50–70% and lowered the risk of MACE by 12% (OR 0.88). Minimal heterogeneity (I2 = 0%) indicated consistency across studies. Subgroup analysis showed greater efficacy in high-risk populations (e.g., acute coronary syndrome and familial hypercholesterolemia). Adverse events were mild, with minimal muscle-related side effects. Conclusion: PCSK9 inhibitors are effective and safe alternatives for LDL-C reduction and cardiovascular risk mitigation in patients with statin intolerance. Their efficacy, favorable safety profile, and consistency across studies highlight their potential for managing dyslipidemia, particularly in high-risk groups. Further research on long-term outcomes is required.

Dapagliflozin modulates hepatic lipid metabolism through the proprotein convertase subtilisin/kexin type 9/low density lipoprotein receptor pathway.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is mainly secreted by the liver, and plays a crucial role in lipid metabolism disorder. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) can regulate lipid metabolism through various pathways, including reducing visceral fat accumulation, modulating serum lipoprotein levels and alleviating hepatic steatosis. However, the specific regulatory mechanisms remain unclear. We built a model of glucose and lipid metabolism disorder in vivo and in vitro, and explored the regulatory mechanism of dapagliflozin in regulating liver lipid metabolism. We found that the SGLT2i dapagliflozin significantly reduced serum levels of PCSK9, total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) in high-fat diet (HFD)-fed mice, while also improving hepatic steatosis. In vitro studies confirmed that dapagliflozin increased LDL receptor (LDLR) expression in HepG2 cells, enhancing their ability to uptake LDL-C. Further mechanistic studies revealed that the hepatocyte nuclear factor-1-alpha (HNF1α)/PCSK9/LDLR signalling pathway may be involved in dapagliflozin's regulation of lipid metabolism homeostasis.