Expression of pro- and anti-inflammatory cytokines during anti-proprotein convertase subtilisin/kexin type 9 therapy in patients with statin-resistant familial hypercholesterolemia.

Background: Some clinical dyslipidemia cases do not respond to statins, known as statin-resistant familial hypercholesterolemia (SR-FH), in which patients are under a high cardiovascular risk despite statin therapy. Therefore, novel therapeutic alternatives are required. Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) reduce cholesterol levels and cardiovascular disease risk, particularly in patients with SR-FH, where PCSK9i may differentially affect pro- and anti-inflammatory mediators depending on the clinical setting. Aim: To evaluate the effect of PCSK9i treatment on pro- and anti-inflammatory cytokines in patients with SR-FH. Methods: Before-after comparison, quasi-experimental, single-center study in patients with SR-FH. Blood samples were processed to obtain complete blood counts of glycated hemoglobin and serum lipid levels. Flow cytometry was performed to characterize baseline circulating M1- and M2-macrophages and monocytes. Multiplexing of plasma samples was used to compare plasma fraktaline, interleukins (ILs), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor (TNF)-alpha. The endpoints were lower serum lipid levels and pro-inflammatory mediator modification. Results: Twenty patients with SR-FH, aged 58 years and most of them males, were included, with a mean body-mass index of 26.4 and showing ischemic heart disease and similar values of baseline M1- and M2-macrophages and monocytes. Six-month iPSCK-9 therapy considerably reduced LDLc, increased anti-inflammatory cytokine (IL-4), and modified pro-inflammatory cytokine (TNF-alpha and MCP-1) levels. No notable effects were observed for the other markers. Conclusion: PCSK9i therapy exerted subclinical anti-inflammatory and anti-atherogenic effects, indicating potential benefits for clinical outcomes.

The Predictive Utility of Circulating PCSK9 Levels on Diabetic Retinopathy Stage.

PURPOSE: To investigate the value of proprotein-converting subtilisin kexin type 9 (PCSK9) levels in type 2 diabetes mellitus (T2D) patients with different stages of diabetic retinopathy (DR) and to compare these findings with a healthy control group without diabetes mellitus (DM). METHODS: A total of 135 patients, 100 of whom were patients with T2D and 35 of whom were in the health control group, were included in this prospective study. T2D patients were divided into three groups: the first group included 34 people with T2D without DR, the second group had 32 people with non-proliferative DR (NPDR), and the third group had 34 people with proliferative DR (PDR). Serum PCSK9 levels were analyzed and compared between the groups. RESULTS: Forty-nine percent of the participants were female, and the mean age was 64 ± 9.1 years, with no statistically significant results between the four groups in terms of age and sex. The mean serum PCSK9 value was significantly different (p = 0.01) when all groups were evaluated, and statistically significant change was observed with the progression of DR. When serum PCSK9 levels were evaluated in all T2D patients (groups 1, 2, and 3), a medium-level correlation was observed with low-density lipoprotein (p < 0.05). CONCLUSION: Serum PCSK9 values differed significantly in diabetic patients compared to the control group. One should be clinically cautious about the usefulness of circulating PCSK9 concentrations as an indicator of the risk of diabetic retinopathy.

Exploring the causal effect between lipid-modifying drugs and idiopathic pulmonary fibrosis: a drug-target Mendelian randomization study.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a respiratory disorder of obscure etiology and limited treatment options, possibly linked to dysregulation in lipid metabolism. While several observational studies suggest that lipid-lowering agents may decrease the risk of IPF, the evidence is inconsistent. The present Mendelian randomization (MR) study aims to determine the association between circulating lipid traits and IPF and to assess the potential influence of lipid-modifying medications for IPF. METHODS: Summary statistics of 5 lipid traits (high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, apolipoprotein A, and apolipoprotein B) and IPF were sourced from the UK Biobank and FinnGen Project Round 10. The study's focus on lipid-regulatory genes encompassed PCSK9, NPC1L1, ABCG5, ABCG8, HMGCR, APOB, LDLR, CETP, ANGPTL3, APOC3, LPL, and PPARA. The primary effect estimates were determined using the inverse-variance-weighted method, with additional analyses employing the contamination mixture method, robust adjusted profile score, the weighted median, weighted mode methods, and MR-Egger. Summary-data-based Mendelian randomization (SMR) was used to confirm significant lipid-modifying drug targets, leveraging data on expressed quantitative trait loci in relevant tissues. Sensitivity analyses included assessments of heterogeneity, horizontal pleiotropy, and leave-one-out methods. RESULTS: There was no significant effect of blood lipid traits on IPF risk (all P＞0.05). Drug-target MR analysis indicated that genetic mimicry for inhibitor of NPC1L1, PCSK9, ABCG5, ABCG8, and APOC3 were associated with increased IPF risks, with odds ratios (ORs) and 95% confidence intervals (CIs) as follows: 2.74 (1.05-7.12, P = 0.039), 1.36 (1.02-1.82, P = 0.037), 1.66 (1.12-2.45, P = 0.011), 1.68 (1.14-2.48, P = 0.009), and 1.42 (1.20-1.67, P = 3.17×10-5), respectively. The SMR method identified a significant association between PCSK9 gene expression in whole blood and reduced IPF risk (OR = 0.71, 95% CI: 0.50-0.99, P = 0.043). Sensitivity analyses showed no evidence of bias. CONCLUSIONS: Serum lipid traits did not significantly affect the risk of idiopathic pulmonary fibrosis. Drug targets MR studies examining 12 lipid-modifying drugs indicated that PCSK9 inhibitors could dramatically increase IPF risk, a mechanism that may differ from their lipid-lowering actions and thus warrants further investigation.

Clinical Impact of Lipoprotein (a) and Cumulative Low-Density Lipoprotein Cholesterol Exposure on Coronary Artery Disease in Patients with Heterozygous Familial Hypercholesterolemia.

AIMS: Elevated lipoprotein (a) (Lp[a]), predominantly determined by genetic variability, causes atherosclerotic cardiovascular disease (ASCVD), particularly in patients with familial hypercholesterolemia (FH). We aimed to elucidate the clinical impact of Lp(a) and cumulative exposure to low-density lipoprotein cholesterol (LDL-C) on CAD in patients with FH. METHODS: One hundred forty-seven patients clinically diagnosed with heterozygous familial hypercholesterolemia (HeFH) were retrospectively investigated. Patients were divided into 2 groups according to the presence of CAD. Their clinical characteristics and lipid profiles were evaluated. RESULTS: There were no significant differences in untreated LDL-C levels between the 2 groups (p=0.4), whereas the cumulative exposure to LDL-C and Lp(a) concentration were significantly higher in patients with CAD (11956 vs. 8824 mg-year/dL, p＜0.01; 40 vs. 14 mg/dL, p＜0.001, respectively). A receiver operating characteristic (ROC) curve analysis demonstrated that the cutoff values of Lp(a) and cumulative LDL-C exposure to predict CAD in patients with FH were 28 mg/dL (AUC 0.71) and 10600 mg-year/dL (AUC 0.77), respectively. A multivariate analysis revealed that cumulative LDL-C exposure ≥ 10600 mg-year/dL (p＜0.0001) and Lp(a) level ≥ 28 mg/dL (p＜0.001) were independent predictors of CAD. Notably, the risk of CAD remarkably increased to 85.7% with smoking, Lp(a) ≥ 28 mg/dL, and cumulative LDL-C exposure ≥ 10600 mg-year/dL (odds ratio: 46.5, 95%CI: 5.3-411.4, p＜0.001). CONCLUSIONS: This study demonstrated an additive effect of Lp(a) and cumulative LDL-C exposure on CAD in patients with HeFH. Interaction with traditional risk factors, particularly smoking and cumulative LDL-C exposure, enormously enhances the cardiovascular risk in this population.

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

AIM: To investigate medication adherence and treatment persistence in patients receiving proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibodies (mAbs) in Japan. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

PCSK9 inhibitors and the risk of vitiligo: a Mendelian randomization study.

Lipid-lowering agents have been suggested as a therapeutic option for vitiligo based on the potential pathogenic role of lipid metabolism abnormalities. We aimed to explore the impact of genetically proxied lipid-lowering agents on the risk of vitiligo and potentially associated mediators. Genome-wide association study summary statistics for European ancestry were extracted from the largest available meta-analysis for vitiligo, the Global Lipids Genetics Consortium for seven lipid profiles, and two large biobanks, UKB and deCODE, for 4,719 proteins. After identifying lipid-lowering agents with genetically proxied protective effects against vitiligo using lipid-lowering and protein-inhibition Mendelian randomization (MR) analyses, multivariable and two-step MR analyses were conducted to identify potential mediators between lipid-lowering agents and vitiligo. Lipid-lowering MR indicated a potential role of PCSK9 in reducing the vitiligo risk (OR[95%CI] = 0.71[0.52-0.95]), which was replicated in PCSK9-inhibition MR analyses across two separate biobanks (UKB: OR[95%CI]=0.82[0.71-0.96]; deCODE: OR[95%CI]=0.78[0.67-0.91]). Multivariable MR suggested that well-known lipid profiles do not mediate the relationship between PCSK9 and vitiligo, while two-step MR analyses identified five potential protein mediators (CCN5, CXCL12, FCRL1, LGMN, and FGF2). Hence, PCSK9 inhibitor may attenuate the vitiligo risk; PCSK9 and the potential protein mediators can serve as promising novel therapeutic targets for its effective treatment.

Inhibition of PCSK9 enhances the anti-hepatocellular carcinoma effects of TCR-T cells and anti-PD-1 immunotherapy.

T cells play important roles in antitumor immunity. However, given that the hepatocellular carcinoma (HCC) tumor microenvironment confers resistance to T cell-based immunotherapies, novel strategies to boost T cell-mediated antitumor efficacy are urgently needed for the treatment of HCC. Here, we show that high proprotein convertase subtilisin/kexin type9 (PCSK9) expression was negatively associated with HCC patient's overall survival and markers of CD8+ T cells. Pharmacological inhibition of PCSK9 enhanced tumor-specific killing and downregulated PD-1 expression of AFP-specific TCR-T. Inhibition of PCSK9 significantly enhances the anti-HCC efficacy of TCR-T cells and anti-PD-1 immunotherapy in vivo. Moreover, PCSK9 inhibitor suppressed HCC growth dependent on CD8+ T cells. Mechanically, pharmacological inhibition of PCSK9 promoted low-density lipoprotein receptor (LDLR)-mediated activation of mTORC1 signaling in CD8+ T cells. LDLR deficiency was shown to impair cellular mTORC1 signaling and the anti-HCC function of CD8 T cells. On the basis of our findings in this study, we propose a potential metabolic intervention strategy that could be used to enhance the antitumor effects of immunotherapy for HCC.

The role of proprotein convertase subtilisin/kexin 9 (PCSK9) in macrophage activation: a focus on its LDL receptor-independent mechanisms.

Recent clinical trials demonstrated that proprotein convertase subtilisin/kexin 9 (PCSK9) inhibitors reduce cardiovascular events without affecting systemic inflammation in the patients with coronary artery disease, as determined by high sensitivity C-reactive protein (CRP) levels. However, its pro-inflammatory effects in cardiovascular disease in humans and experimental animals beyond the traditional cholesterol receptor-dependent lipid metabolism have also called attention of the scientific community. PCSK9 may target receptors associated with inflammation other than the low-density lipoprotein receptor (LDLR) and members of the LDLR family. Accumulating evidence suggests that PCSK9 promotes macrophage activation not only via lipid-dependent mechanisms, but also lipid-independent and LDLR-dependent or -independent mechanisms. In addition to dyslipidemia, PCSK9 may thus be a potential therapeutic target for various pro-inflammatory diseases.

Early and short-term use of proprotein convertase anti-subtilisin-kexin type 9 inhibitors on coronary plaque stability in acute coronary syndrome.

Aims: Proprotein convertase anti-subtilisin-kexin type 9 inhibitors (PCSK9Is) improve plaque volume and composition and reduce major adverse coronary events in chronic coronary artery disease. We evaluated the effects of the short-term use of PCSK9Is on coronary plaque stability in patients with acute coronary syndrome (ACS) using optical coherence tomography (OCT). Methods and results: This is a multicentre, open-label randomized controlled trial. The enrolled 80 subjects met the inclusion criteria. Of these, 52 patients (age 60 ± 11 years, 38 men, 14 women) with ST-elevated ACS had undergone successful primary percutaneous coronary intervention with LDL-cholesterol (LDL-C) levels > 70 mg/dL while receiving high-intensity statins. Participants were randomly assigned to the PCSK9I group (evolocumab 420 mg for 3 months, n = 29) or the standard of care (SoC) group (n = 23). Optical coherence tomography was performed at baseline (BL) and 3 and 9 months after randomization to assess lipid-rich plaques in non-culprit lesions. The change in the minimum fibrous cap thickness (MFCT) from BL to 9 months was the primary endpoint. The percentage change in LDL-C levels from BL to 3 months was significantly greater in the PCSK9I group (-67.8 ± 21.5% in the PCSK9I group vs. -16.3 ± 21.8% in the SoC group; P < 0.0001), and the difference between the two groups disappeared from BL to 9 months (-20.0 ± 37.8% in the PCSK9I group vs. -6.7 ± 34.2% in the SoC group; P = 0.20). The changes in MFCT from BL to 9 months were significantly greater in the PCSK9I group, even after PCSK9I discontinuation {100 µm [interquartile range (IQR): 45-180 µm] vs. 50 µm [IQR: 0-110 µm]; P = 0.032}. Conclusion: Combination treatment with PCSK9Is and statins resulted in more marked plaque stabilization after ACS than SoC alone, and this effect persisted for 6 months after PCSK9I discontinuation. Registration: Adage-Joto study, UMIN ID No. 26516.

E3 ubiquitin ligase MARCH1 reduces inflammation and pyroptosis in cerebral ischemia-reperfusion injury via PCSK9 downregulation.

Pyroptosis has been regarded as caspase-1-mediated monocyte death that induces inflammation, showing a critical and detrimental role in the development of cerebral ischemia-reperfusion injury (IRI). MARCH1 is an E3 ubiquitin ligase that exerts potential anti-inflammatory functions. Therefore, the study probed into the significance of MARCH1 in inflammation and pyroptosis elicited by cerebral IRI. Middle cerebral artery occlusion/reperfusion (MCAO/R)-treated mice and oxygen glucose deprivation/reoxygenation (OGD/R)-treated hippocampal neurons were established to simulate cerebral IRI in vivo and in vitro. MARCH1 and PCSK9 expression was tested in MCAO/R-operated mice, and their interaction was identified by means of the cycloheximide assay and co-immunoprecipitation. The functional roles of MARCH1 and PCSK9 in cerebral IRI were subsequently determined by examining the neurological function, brain tissue changes, neuronal viability, inflammation, and pyroptosis through ectopic expression and knockdown experiments. PCSK9 expression was increased in the brain tissues of MCAO/R mice, while PCSK9 knockdown reduced brain damage and neurological deficits. Additionally, inflammation and pyroptosis were inhibited in OGD/R-exposed hippocampal neurons upon PCSK9 knockdown, accompanied by LDLR upregulation and NLRP3 inflammasome inactivation. Mechanistic experiments revealed that MARCH1 mediated ubiquitination and degradation of PCSK9, lowering PCSK9 protein expression. Furthermore, it was demonstrated that MARCH1 suppressed inflammation and pyroptosis after cerebral IRI by downregulating PCSK9 both in vivo and in vitro. Taken together, the present study demonstrate the protective effect of MARCH1 against cerebral IRI through PCSK9 downregulation, which might contribute to the discovery of new therapies for improving cerebral IRI.

PCSK9 inhibitor effectively alleviated cognitive dysfunction in a type 2 diabetes mellitus rat model.

Background: The incidence of diabetes-associated cognitive dysfunction (DACD) is increasing; however, few clinical intervention measures are available for the prevention and treatment of this disease. Research has shown that proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, particularly SBC-115076, have a protective effect against various neurodegenerative diseases. However, their role in DACD remains unknown. In this study, we aimed to explore the impact of PCSK9 inhibitors on DACD. Methods: Male Sprague-Dawley (SD) rats were used to establish an animal model of type 2 diabetes mellitus (T2DM). The rats were randomly divided into three groups: the Control group (Control, healthy rats, n = 8), the Model group (Model, rats with T2DM, n = 8), and the PCSK9 inhibitor-treated group (Treat, T2DM rats treated with PCSK9 inhibitors, n = 8). To assess the spatial learning and memory of the rats in each group, the Morris water maze (MWM) test was conducted. Hematoxylin-eosin staining and Nissl staining procedures were performed to assess the structural characteristics and functional status of the neurons of rats from each group. Transmission electron microscopy was used to examine the morphology and structure of the hippocampal neurons. Determine serum PCSK9 and lipid metabolism indicators in each group of rats. Use qRT-PCR to detect the expression levels of interleukin (IL)-1ß, IL-6, and tumor necrosis factor-alpha (TNF-α) in the hippocampal tissues of each group of rats. Western blot was used to detect the expression of PCSK9 and low-density lipoprotein receptor (LDLR) in the hippocampal tissues of rats. In addition, a 4D label-free quantitative proteomics approach was used to analyse protein expression in rat hippocampal tissues. The expression of selected proteins in hippocampal tissues was verified by parallel reaction monitoring (PRM) and immunohistochemistry (IHC). Results: The results showed that the PCSK9 inhibitor alleviated cognitive dysfunction in T2DM rats. PCSK9 inhibitors can reduce PCSK9, total cholesterol (TC), and low-density lipoprotein (LDL) levels in the serum of T2DM rats. Meanwhile, it was found that PCSK9 inhibitors can reduce the expression of PCSK9, IL-1ß, IL-6, and TNF-α in the hippocampal tissues of T2DM rats, while increasing the expression of LDLR. Thirteen potential target proteins for the action of PCSK9 inhibitors on DACD rats were identified. PRM and IHC revealed that PCSK9 inhibitors effectively counteracted the downregulation of transthyretin in DACD rats. Conclusion: This study uncovered the target proteins and specific mechanisms of PCSK9 inhibitors in DACD, providing an experimental basis for the clinical application of PCSK9 inhibitors for the potential treatment of DACD.

Benefits of intensive lipid-lowering therapies in patients with acute coronary syndrome: a systematic review and meta-analysis.

BACKGROUND: Previous meta-analyses have investigated the efficacy of lipid-lowering therapies for atherosclerotic cardiovascular disease; however, few have focused on patients with acute coronary syndrome (ACS). This meta-analysis aimed to compare the benefits of intensive lipid-lowering therapy with those of background statin therapy in patients with ACS. METHODS: Searches were performed on PubMed, Embase, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov databases for articles published until April 13, 2023. Randomized controlled trials that compared intensive lipid-lowering therapies and background statin therapies in patients with prior ACS and recorded the outcome of three-point major cardiovascular events (MACE) were included. The risk ratio (RR) with 95% confidence interval (CI) was used as a measure of primary and secondary outcomes. RESULTS: Nine trials involving 38,640 patients with ACS were identified. Pooled results suggested that intensive lipid-lowering therapies are associated with a reduction in the risk of three-point MACE (RR, 0.88; 95% CI, 0.83-0.94; p < 0.001), recurrent ACS (RR, 0.82; 95% CI, 0.71-0.96; p = 0.013), nonfatal myocardial infarction (MI) (RR, 0.87; 95% CI, 0.81-0.93; p < 0.001), stroke (RR, 0.83; 95% CI, 0.73-0.94; p = 0.003), and unstable angina-related hospitalization (RR, 0.57; 95% CI, 0.33-0.99; p = 0.046), but not all-cause mortality (RR, 0.94; 95% CI, 0.82-1.07; p = 0.329), cardiovascular disease-related mortality (RR, 0.96; 95% CI, 0.88-1.06; p = 0.457) or coronary revascularization (RR, 0.89; 95% CI, 0.79-1.00; p = 0.057). CONCLUSIONS: Intensive lipid-lowering therapies may reduce the risk of three-point MACE, recurrent ACS, nonfatal MI, stroke, and hospitalization for unstable angina in patients with ACS undergoing background statin therapy. These results may assist in clinical decision-making for the secondary prevention of cardiovascular events to initiate intensive lipid-lowering therapies immediately after ACS.

The clinical relevance of the reversal of coronary atherosclerotic plaque.

Atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of death globally despite advances in preventive therapies. Understanding of the initiation and progression of atherosclerosis, the interplay between lipoproteins, endothelial dysfunction, inflammation, and immune responses is critical to treating this disease. The development of vulnerable coronary plaques prone to thrombosis, can lead to acute coronary syndromes, for these reasons, the potential plaque stabilization and regression through pharmacological interventions, particularly lipid-lowering agents like statins and PCSK9 inhibitors is crucial. The imaging techniques such as intravascular ultrasound (IVUS), near-infrared spectroscopy (NIRS), and optical coherence tomography (OCT) play a key role in assessing plaque composition and guiding interventional therapeutic strategies. Clinical evidence supports the efficacy of intensive lipid-lowering therapy in inducing plaque regression, with studies demonstrating reductions in plaque volume and improvements in plaque morphology assessed by IVUS, OCT and NIRS. While pharmacological interventions show promise in promoting plaque regression and stabilization, their impact on long-term cardiovascular events requires further investigation. Multimodality imaging and comprehensive outcome trials are proposed as essential tools for elucidating the relationship between plaque modification and clinical benefit in coronary atherosclerosis. The stabilization or regression of atherosclerotic plaque might serve as the phenomenon linking the reduction in LDL-C levels to the decrease in cardiovascular events. Overall, this review emphasizes the ongoing efforts to advance our understanding of ASCVD pathophysiology and optimize therapeutic approaches for improving patient outcomes.

Ferritin-based disruptor nanoparticles: A novel strategy to enhance LDL cholesterol clearance via multivalent inhibition of PCSK9-LDL receptor interaction.

Hypercholesterolemia, characterized by elevated low-density lipoprotein (LDL) cholesterol levels, is a significant risk factor for cardiovascular disease. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a crucial role in cholesterol metabolism by regulating LDL receptor degradation, making it a therapeutic target for mitigating hypercholesterolemia-associated risks. In this context, we aimed to engineer human H ferritin as a scaffold to present 24 copies of a PCSK9-targeting domain. The rationale behind this protein nanoparticle design was to disrupt the PCSK9-LDL receptor interaction, thereby attenuating the PCSK9-mediated impairment of LDL cholesterol clearance. The N-terminal sequence of human H ferritin was engineered to incorporate a 13-amino acid linear peptide (Pep2-8), which was previously identified as the smallest PCSK9 inhibitor. Exploiting the quaternary structure of ferritin, engineered nanoparticles were designed to display 24 copies of the targeting peptide on their surface, enabling a multivalent binding effect. Extensive biochemical characterization confirmed precise control over nanoparticle size and morphology, alongside robust PCSK9-binding affinity (KD in the high picomolar range). Subsequent efficacy assessments employing the HepG2 liver cell line demonstrated the ability of engineered ferritin's ability to disrupt PCSK9-LDL receptor interaction, thereby promoting LDL receptor recycling on cell surfaces and consequently enhancing LDL uptake. Our findings highlight the potential of ferritin-based platforms as versatile tools for targeting PCSK9 in the management of hypercholesterolemia. This study not only contributes to the advancement of ferritin-based therapeutics but also offers valuable insights into novel strategies for treating cardiovascular diseases.

Increase of PCSK9 expression in diabetes promotes VEGFR2 ubiquitination to inhibit endothelial function and skin wound healing.

Diabetic foot ulcers (DFUs) are a serious vascular disease. Currently, no effective methods are available for treating DFUs. Pro-protein convertase subtilisin/kexin type 9 (PCSK9) regulates lipid levels to promote atherosclerosis. However, the role of PCSK9 in DFUs remains unclear. In this study, we found that the expression of PCSK9 in endothelial cells (ECs) increased significantly under high glucose (HG) stimulation and in diabetic plasma and vessels. Specifically, PCSK9 promotes the E3 ubiquitin-protein ligase NEDD4 binding to vascular endothelial growth factor receptor 2 (VEGFR2), which led to the ubiquitination of VEGFR2, resulting in its degradation and downregulation in ECs. Furthermore, PCSK9 suppresses the expression and activation of AKT, endothelial nitric oxide synthase (eNOS), and ERK1/2, leading to decreased nitric oxide (NO) production and increased superoxide anion (O2._) generation, which impairs vascular endothelial function and angiogenesis. Importantly, using evolocumab to limit the increase in PCSK9 expression blocked the HG-induced inhibition of NO production and the increase in O2._ production, as well as inhibited the phosphorylation and expression of AKT, eNOS, and ERK1/2. Moreover, evolocumab improved vascular endothelial function and angiogenesis, and promoted wound healing in diabetes. Our findings suggest that targeting PCSK9 is a novel therapeutic approach for treating DFUs.

Proprotein convertase subtilisin/kexin type 9 deficiency in extrahepatic tissues: emerging considerations.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is primarily secreted by hepatocytes. PCSK9 is critical in liver low-density lipoprotein receptors (LDLRs) metabolism. In addition to its hepatocellular presence, PCSK9 has also been detected in cardiac, cerebral, islet, renal, adipose, and other tissues. Once perceived primarily as a "harmful factor," PCSK9 has been a focal point for the targeted inhibition of both systemic circulation and localized tissues to treat diseases. However, PCSK9 also contributes to the maintenance of normal physiological functions in numerous extrahepatic tissues, encompassing both LDLR-dependent and -independent pathways. Consequently, PCSK9 deficiency may harm extrahepatic tissues in close association with several pathophysiological processes, such as lipid accumulation, mitochondrial impairment, insulin resistance, and abnormal neural differentiation. This review encapsulates the beneficial effects of PCSK9 on the physiological processes and potential disorders arising from PCSK9 deficiency in extrahepatic tissues. This review also provides a comprehensive analysis of the disparities between experimental and clinical research findings regarding the potential harm associated with PCSK9 deficiency. The aim is to improve the current understanding of the diverse effects of PCSK9 inhibition.

MRG15 aggravates sepsis-related liver injury by promoting PCSK9 synthesis and secretion.

OBJECTIVE: Disorders of lipid oxidation play an important role in organ damage, and lipid metabolites are associated with inflammation and coagulation dysfunction in sepsis. However, the specific molecular mechanism by which lipid metabolism-related proteins regulate sepsis is still unclear. The aim of this study is to investigate the role of mortality factor 4-like protein 1 (MORF4L1, also called MRG15), a hepatic lipid metabolism related gene, in sepsis-induced liver injury. METHODS: In the mouse sepsis models established by cecal ligation and puncture (CLP) and lipopolysaccharide (LPS), the impact of pretreatment with the MRG15 inhibitor argatroban on sepsis-related liver injury was investigated. In the LPS-induced hepatocyte sepsis cell model, the effects of MRG15 overexpression or knockdown on hepatic inflammation and lipid metabolism were studied. Additionally, in a co-culture system of hepatocytes and macrophages, the influence of MRG15 knockdown in hepatocytes on the synthesis and secretion of inflammation-related protein PCSK9 as well as its effect on macrophage activation were examined. RESULTS: Studies have shown that MRG15 expression was increased in septicemia mice and positively correlated with lipid metabolism and inflammation. However, knockdown of MRG15 ameliorates sepsis-induced hepatocyte injury. Increased MRG15 in LPS-stimulated hepatocytes promotes PCSK9 synthesis and secretion, which induces macrophage M1 polarization and exacerbates the inflammatory response. Agatroban, an inhibitor of MRG15, ameliorates sepsis-induced liver injury in mice by inhibiting MRG15-induced lipid metabolism disorders and inflammatory responses. CONCLUSIONS: In sepsis, increased MRG15 expression in hepatocytes leads to disturbed hepatic lipid metabolism and induces macrophage M1 polarization by secreting PCSK9, ultimately exacerbating liver injury.

PCSK9 and Coronary Artery Plaque-New Opportunity or Red Herring?

PURPOSE OF REVIEW: Although the clinical benefit of reducing low-density lipoprotein cholesterol (LDLc) in patients with coronary artery disease (CAD) is well-established, the impact on plaque composition and stability is less clear. Our narrative review aimed to assess the clinical effects of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors on coronary plaque characteristics specifically focusing from atheroma progression to regression and stabilization. RECENT FINDINGS: The combination of statin therapy and PCSK9 inhibitors (evolocumab and alirocumab) promotes plaque stability in patients following an acute coronary syndrome. The GLAGOV study highlighted the relationship between achieved LDLc levels and changes in percentage atheroma volume. Similarly, the PACMAN-AMI study concluded that the qualitative and quantitative changes in coronary plaque were associated with the levels of LDLc. Assessing the severity of coronary artery stenosis and the extent of atherosclerotic burden by means of imaging techniques (e.g., IVUS, OCT and near-infrared spectroscopic) have significantly advanced our understanding of the benefits from promoting plaque regression and achieving to features of plaque stabilization through increasingly intensive lipid-lowering strategies.

Association between PCSK9 inhibitors and acute kidney injury: a pharmacovigilance study.

Background: PCSK9 inhibitors are a novel class of lipid-lowering medications, and numerous clinical studies have confirmed their significant role in improving the progression of chronic kidney disease. However, recent case reports have indicated new evidence regarding their association with acute kidney injury (AKI), with some patients experiencing acute tubular injury after PCSK9 inhibitors use. Objectives: To clarify the relationship between PCSK9 inhibitors and AKI, we conducted a pharmacovigilance study. Methods: Using the Food and Drug Administration Adverse Event Reporting System (FAERS) database from the third quarter of 2015 to the fourth quarter of 2022, a disproportionality analysis was employed to identify adverse events suggestive of AKI after PCSK9 inhibitors use. The drugs of interest included evolocumab and alirocumab. Results: A total of 144,341 adverse event reports related to PCSK9 inhibitors were analyzed, among which 444 cases were suspected of AKI for evolocumab, and 172 cases for alirocumab. Evolocumab had a greater impact on AKI in males (ROR 1.4, 95% CI 1.54-1.69). The ROR and 95% CI for evolocumab and Alirocumab were 0.13 (0.12-0.14) and 0.26 (0.23-0.30) respectively. Further analysis of AKI associated with the concomitant use of PCSK9 inhibitors with cephalosporins, furosemide, torsemide, pantoprazole, omeprazole, and esomeprazole revealed ROR and 95% CI of 0.38 (0.23-0.62), 0.38 (0.31-0.48), 0.18 (0.08-0.38), 0.23 (0.17-0.29), 0.20 (0.16-0.26), and 0.14 (0.10-0.20) respectively. Conclusion: Through the FAERS database, we analyzed the clinical characteristics of AKI associated with PCSK9 inhibitors, exploring its risks. Our findings suggest that PCSK9 inhibitors might have a potential protective effect against AKI and exhibit similar effects when co-administered with other nephrotoxic drugs.