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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. [ABSTRACT FROM AUTHOR]

Proprotein convertase subtilisin/kexin type-9 (PCSK9) is a protein that regulates low-density lipoprotein (LDL) cholesterol metabolism by binding to the hepatic LDL receptor (LDLR), ultimately leading to its lysosomal degradation and an increase in LDL cholesterol (LDLc) levels. Treatment strategies have been developed based on blocking PCSK9 with specific antibodies (alirocumab, evolocumab) and on blocking its production with small regulatory RNA (siRNA) (inclisiran). Clinical trials evaluating these drugs have confirmed their high efficacy in reducing serum LDLc levels and improving the prognosis in patients with atherosclerotic cardiovascular diseases. Most studies have focused on the action of PCSK9 on LDLRs and the subsequent increase in LDLc concentrations. Increasing evidence suggests that the adverse cardiovascular effects of PCSK9, particularly its atherosclerotic effects on the vascular wall, may also result from mechanisms independent of its effects on lipid metabolism. PCSK9 induces the expression of pro-inflammatory cytokines contributing to inflammation within the vascular wall and promotes apoptosis, pyroptosis, and ferroptosis of cardiomyocytes and is thus involved in the development and progression of heart failure. The elimination of PCSK9 may, therefore, not only be a treatment for hypercholesterolaemia but also for atherosclerosis and other cardiovascular diseases. The mechanisms of action of PCSK9 in the cardiovascular system are not yet fully understood. This article reviews the current understanding of the mechanisms of PCSK9 action in the cardiovascular system and its contribution to cardiovascular diseases. Knowledge of these mechanisms may contribute to the wider use of PCSK9 inhibitors in the treatment of cardiovascular diseases. [ABSTRACT FROM AUTHOR]

Proprotein convertase subtilisin/kexin type 9 (PCSK9), a well-known regulator of cholesterol metabolism and cardiovascular diseases, has recently garnered attention for its emerging involvement in cancer biology. The multifunctional nature of PCSK9 extends beyond lipid regulation and encompasses a wide range of cellular processes that can influence cancer progression. Studies have revealed that PCSK9 can modulate signaling pathways, such as PI3K/Akt, MAPK, and Wnt/β-catenin, thereby influencing cellular proliferation, survival, and angiogenesis. Additionally, the interplay between PCSK9 and cholesterol homeostasis may impact membrane dynamics and cellular migration, further influencing tumor aggressiveness. The central role of the immune system in monitoring and controlling cancer is increasingly recognized. Recent research has demonstrated the ability of PCSK9 to modulate immune responses through interactions with immune cells and components of the tumor microenvironment. This includes effects on dendritic cell maturation, T cell activation, and cytokine production, suggesting a role in shaping antitumor immune responses. Moreover, the potential influence of PCSK9 on immune checkpoints such as PD1/PD-L1 lends an additional layer of complexity to its immunomodulatory functions. The growing interest in cancer immunotherapy has prompted exploration into the potential of targeting PCSK9 for therapeutic benefits. Preclinical studies have demonstrated synergistic effects between PCSK9 inhibitors and established immunotherapies, offering a novel avenue for combination treatments. The strategic manipulation of PCSK9 to enhance tumor immunity and improve therapeutic outcomes presents an exciting area for further investigations. Understanding the mechanisms by which PCSK9 influences cancer biology and immunity holds promise for the development of novel immunotherapeutic approaches. This review aims to provide a comprehensive analysis of the intricate connections between PCSK9, cancer pathogenesis, tumor immunity, and the potential implications for immunotherapeutic interventions. [ABSTRACT FROM AUTHOR]

Sepsis is a life-threatening condition that arises when the body's response to infection causes injury to its tissues and organs. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is an enzyme released in response to the drop in cholesterol level occurring in sepsis. Our study aimed to evaluate the prognostic role of serum Proprotein convertase subtilisin/kexin type 9 (PCSK9) level in children with sepsis and severe sepsis. Sixty children were included in this study. They were divided into two groups: 30 children in the sepsis group and 30 in the severe sepsis group. Another 30 apparently healthy children were included as a control group. Blood samples were withdrawn from all included children for complete blood count (CBC), renal function tests (RFT), liver function tests (LFT), LDL-cholesterol (LDL-C), blood culture, and serum PCSK9. In this study, PCSK9 and LDL-C were higher in the two sepsis groups than in the control group (p < 0.05). They were also higher in the severe sepsis group than the sepsis group and in the non-survivors than in the survivors (p < 0.05). PCSK9 was positively correlated with length of hospital stay in surviving children (r = 0.67, p = 0.001) and had predicted significant hematological dysfunction (adjusted B = − 96.95, p = 0.03). In conclusion, the PCSK9 assay can be used as a biomarker for bad prognosis in children suffering from clinical sepsis. [ABSTRACT FROM AUTHOR]

Purpose of Review: Globally, the prevalence of metabolic disorders is rising. Elevated low-density lipoprotein (LDL) cholesterol is a hallmark of familial hypercholesterolemia, one of the most prevalent hereditary metabolic disorders and another one is Diabetes mellitus (DM) that is more common globally, characterised by hyperglycemia with low insulin-directed glucose by target cells. It is still known that low-density lipoprotein cholesterol (LDL-C) increases the risk of cardiovascular disease (CVD). LDL-C levels are thought to be the main therapeutic objectives. Recent Findings: The primary therapy for individuals with elevated cholesterol levels is the use of statins and other lipid lowering drugs like ezetimibe for hypercholesterolemia. Even after taking statin medication to the maximum extent possible, some individuals still have a sizable residual cardiovascular risk. To overcome this proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors-monoclonal antibodies (mAbs) are a novel class of systemic macromolecules that have enhanced LDL-C-lowering efficacy. Along with this other inhibitor are used like Angiopoeitin like 3 inhibitors. Research on both humans and animals has shown that anti-CD3 antibodies can correct autoimmune disorders like diabetes mellitus. Summary: Individuals diagnosed with familial hypercholesterolemia (FH) may need additional treatment options beyond statins, especially when facing challenges such as statin tolerance or the inability of even the highest statin doses to reach the desired target cholesterol level. Here is the summary of PCSK9, ANGPTL-3 and CD3 inhibitors and their detailed information. In this review we discuss the details of PCSK9, ANGPTL-3 and CD3 inhibitors and the current therapeutic interventions of using the monoclonal antibodies in case of the metabolic disorder. We further present the present studies and the future prospective of the same. [ABSTRACT FROM AUTHOR]

Background: Proprotein convertase subtilisin/kexin type-9 (PCSK9), an enzyme produced mainly by hepatocytes and breaks low-density lipoprotein receptor (LDL-R), inflammatory markers [toll like receptor 4 (TLR4), high mobility group box 1 (HMGB1), tumor necrosis factor alpha (TNFα), c-reactive protein (CRP)], and monocyte subtypes are associated with coronary artery disease (CAD) pathogenesis. The circulating microRNA-218 (miR-218) can relieve CAD through the suppression of HMGB1 in monocyte-derived inflammatory cytokines. Herein, we explored the association between circulatory miR-218 expression and serum levels of PCSK9, inflammatory markers, and monocyte subtypes in statin and non-statin CAD patients. This study involved 91 healthy (control) and 91 stable CAD participants which were subdivided into no-statin (NS, n = 25), low-statin (LS, n = 25), and high-statin (HS, n = 41) groups. low-density lipoprotein cholesterol (LDL-C) and CRP serum levels were calorimetrically determined. Serum levels of PCSK9, TLR4, HMGB1, and TNFα were detected by ELISA, while monocyte subsets [classical (CM), intermediate (IM), non-classical (NC)] were calculated by flow cytometry. Circulatory miR-218 expression was detected by real-time PCR. Results: The CAD group had significantly lower miR-218 expression and significantly higher levels of PCSK9, inflammatory markers (HMGB1, CRP, TLR4, and TNFα), and IM% than the control group. Among CAD patients, LS and HS groups had significantly lower miR-218 expression, LDL-C levels, and inflammatory markers and significantly higher levels of PCSK9 than the NS group. The HS group exhibited the lowest miR-218 expression and inflammatory markers and the highest PCSK9 levels. However, there were no significant changes in IM% among statin and non-statin groups. In the three CAD groups, miR-218 showed a significantly negative correlation with PCSK9 and inflammatory markers (HMGB1, CRP, TLR4, and TNFα), while this expression exhibited a significantly negative correlation with CM%, IM%, and NCM% only in the NS group. Results of multivariable linear regression indicated a correlation between miR-218 and five independent variables (PCSK9, HMGB1, CRP, TLR4, and TNFα) in the total statin (LS + HS) group, and eight independent variables (PCSK9, HMGB1, CRP, TLR4, and TNFα, CM%, IM%, NCM%) in the NS group. Provided that all other independent variables are constant, miR-218 expression was significantly correlated to CRP (Beta = 0.234) and PCSK9 (Beta = − 0.875) in the total statin group; TLR4 (Beta = − 0.554) in the LS group; HMGB1 (Beta = − 0.507) in the HS group; and CRP (Beta = − 0.745) in the NS group. Conclusions: Statin-treated CAD patients have a unique negative correlation between miR-218 and PCSK9, HMGB1, and TLR4, and subsequently with CAD progress. Therefore, it could be recommended to combine activators of miR-218 and inhibitors of PCSK9, HMGB1, and TLR4 with statin to efficiently treat CAD. [ABSTRACT FROM AUTHOR]

Dyslipidaemias are major cardiovascular risk factors, especially in people with diabetes. In this area, next-generation therapies targeting circulating lipoparticle metabolism (LDL, VLDL, chylomicrons, HDL) have recently been approved by the European and US medical agencies, including anti- proprotein convertase subtilisin/kexin 9 (PCSK9) antibodies; an siRNA targeting PCSK9; bempedoic acid, which targets ATP citrate lyase; an antisense oligonucleotide targeting apolipoprotein C-III; an anti-angiopoietin-like 3 antibody; and a purified omega-3 fatty acid, icosapent ethyl. Other therapies are in different phases of development. There are several important considerations concerning the link between these new lipid-lowering therapies and diabetes. First, since concerns were first raised in 2008 about an increased risk of new-onset diabetes mellitus (NODM) with intensive statin treatment, each new lipid-lowering therapy is being evaluated for its associated risk of NODM, particularly in individuals with prediabetes (impaired fasting glucose and/or impaired glucose tolerance). Second, people with diabetes represent a large proportion of those at high or very high cardiovascular risk in whom these lipid-lowering drugs are currently, or will be, prescribed. Thus, the efficacy of these drugs in subgroups with diabetes should also be closely considered, as well as any potential effects on glycaemic control. In this review, we describe the efficacy of next-generation therapies targeting lipoprotein metabolism in subgroups of people with diabetes and their effects on glycaemic control in individuals with diabetes and prediabetes and in normoglycaemic individuals. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed at investigating the role of the proprotein convertase subtilisin/Kexin type 9 (PCSK9)-mediated autophagy on myocardial ischemia/reperfusion injury (MIRI). To determine the relationship between autophagy, apoptosis, fibrosis, and inflammation in the myocardium, to provide experience in preventing and treating the myocardial ischemia/reperfusion (I/R) injury. Methods: An AC16 hypoxia-reoxygenation model and a rat myocardial ischemia–reperfusion model were established. The concentrations of cardiac troponin T (cTnT) and creatine kinase-MB (CKMB) in plasma were measured by ELISA. To determine the size of the myocardial infarction, TTC/EB staining was performed. In addition to identifying pathological changes in myocardial tissue, Masson's trichrome stains and H&E stains were used to identify pathological changes. Echocardiography was employed to detect cardiac function. Western blot analysis was then performed to detect the protein expression of Parkin, Pink1, and markers associated with autophagy (Beclin-1, p62, LC3). Results: A significant increase in PCSK9 was observed in the myocardium during H/R. In the cardiac-specific PCSK9 knockdown model, cardiac autophagy was significantly inhibited, whereas cardiac-specific PCSK9 overexpression promoted cardiac autophagy. In vivo studies have demonstrated a significant decrease in cardiac autophagy when the PCSK9 inhibitor was administered. Apoptosis induced by I/R was greatly decreased, and myocardial infarction size and function were both improved by PCSK9 inhibitors. Mechanistically, the PCSK9 inhibitor improved the degree of myocardial fibrosis and inhibited the development of inflammation. Conclusions: Our results demonstrated that increased PCSK9 via the parkin/pink1 signaling pathway contributes to I/R and H/R by exaggerating excessive autophagy during reperfusion/reoxygenation. In addition, the PCSK9 inhibitor blocked the development of inflammation and improved Infarct size, myocardial function, and myocardial fibrosis. [ABSTRACT FROM AUTHOR]

Background: Lipid pathways play a crucial role in psoriatic arthritis development, and some lipid-lowering drugs are believed to have therapeutic benefits due to their anti-inflammatory properties. Traditional observational studies face issues with confounding factors, complicating the interpretation of causality. This study seeks to determine the genetic link between these medications and the risk of psoriatic arthritis. Methods: This drug target study utilized the Mendelian randomization strategy. We harnessed high-quality data from population-level genome-wide association studies sourced from the UK Biobank and FinnGen databases. The inverse variance-weighted method, complemented by robust pleiotropy methods, was employed. We examined the causal relationships between three lipid-lowering agents and psoriatic arthritis to unveil the underlying mechanisms. Results: A significant association was observed between genetically represented proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition and a decreased risk of psoriatic arthritis (odds ratio [OR]: 0.51; 95% CI 0.14–0.88; P < 0.01). This association was further corroborated in an independent dataset (OR 0.60; 95% CI 0.25–0.94; P = 0.03). Sensitivity analyses affirmed the absence of statistical evidence for pleiotropic or genetic confounding biases. However, no substantial associations were identified for either 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors or Niemann–Pick C1-like 1 inhibitors. Conclusions: This Mendelian randomization analysis underscores the pivotal role of PCSK9 in the etiology of psoriatic arthritis. Inhibition of PCSK9 is associated with reduced psoriatic arthritis risk, highlighting the potential therapeutic benefits of existing PCSK9 inhibitors. [ABSTRACT FROM AUTHOR]

Purpose of Review: Atherosclerotic cardiovascular disease (ASCVD) is a leading cause of premature death. Lipid disorders, particularly elevated serum low-density lipoprotein cholesterol (LDL-C), contribute significantly to ASCVD. The risk of developing ASCVD is influenced by the duration of exposure to elevated LDL-C concentrations (cholesterol-years concept). Implementing lipid-lowering treatments based on the principles of "the earlier the better," "the lower the better," and "the longer the better" has been shown to reduce cardiovascular risk and significantly extend lifespan. Despite the availability of numerous lipid-lowering drugs, achieving satisfactory control of lipid disorders remains very challenging. Therefore, there is a need for novel approaches to improve treatment adherence. Recent Findings: One promising solution under investigation is the development of an anti-PCSK9 vaccine, which could be administered annually to provide long-term control over LDL-C concentrations. Experimental studies and the sole clinical trial conducted thus far have demonstrated that the anti-PCSK9 vaccine induces a durable immune response associated with lipid-lowering and anti-atherosclerotic effects. Furthermore, it has exhibited good tolerability and a satisfactory safety profile. However, we still need data from phase 2, 3, and cardiovascular outcome trial to confirm its safety and efficacy and add value in the armamentarium of available and perspective lipid-lowering drugs. Summary: This article highlights the significance of developing an anti-PCSK9 vaccine and provides an overview of the current knowledge on various anti-PCSK9 vaccines. [ABSTRACT FROM AUTHOR]

Summary: Significant acute cardiovascular, metabolic, and endocrine changes have been traced to short-lasting cold water immersion (CWI); however, the long-term impact of recurrent CWI on atherogenesis, lipid parameters, and fat distribution has not yet been studied. The goal of this study was to investigate the alleged protective effect. A total of 35 healthy volunteers were monitored for a period of 5 months during which the CWI was performed under standardized conditions (three times per week for 7–10 min, without neoprene equipment). Volunteers with measured weight or muscle mass increases of more than 5% were ineligible. An analogous control group (N = 30) was included. At the onset and completion of the study, blood samples were obtained, and clinical assessments took place. PCSK9 and hsCRP levels were measured together with other lipid-related and non-lipid-related indicators. Carotid intima-media thickness test (cIMT) and echo-tracking for the identification of arterial stiffness (PWV, AI, and β) were used to identify early vascular alterations. Hepatorenal index (HRI) calculations served to quantify liver steatosis, while changes in subcutaneous and visceral fat thickness were used to quantify fat distribution. The given protocol was successfully completed by 28 volunteers. Long-term repeated CWI resulted in a significant decline in cIMT (p = 0.0001), AI (p = 0.0002), Beta (p = 0.0001), and PWV (p = 0.0001). PCSK9 (p = 0.01) and hsCRP (p = 0.01) showed a significant decrease when compared to initial values. In comparison to the starting values, liver fat accumulation decreased by 11% on average (HRI p = 0.001). LDL, TC, TG, and VLDL levels all significantly decreased as well. We suggest that repeated CWI may have beneficial impact on lipid, non-lipid, and lipid-related indices, as well as atherogenesis and liver fat storage. [ABSTRACT FROM AUTHOR]

Purpose of Review: To summarize selected late-breaking science on cardiovascular (CV) disease prevention presented at the 2023 European Society of Cardiology (ESC) congress. Recent Findings: The NATURE-PARADOX was a naturally randomized trial that used genetic data from the UK Biobank registry to create "cumulative exposure to low-density lipoprotein-cholesterol (LDL-C)" biomarker and evaluate its association with major CV events regardless of plasma LDL-C levels or age. Safety and efficacy data of inclisiran, a PCSK9-interfering mRNA (PCSK9i) administered subcutaneously twice annually, were presented. Data on two new PCSK9is were presented, recaticimab, an oral drug, and lerodalcibep, a subcutaneous drug with a slightly different architecture than currently available PSCK9is. A phase 1 trial on muvalaplin, an oral lipoprotein (a) inhibitor, was presented. An atherosclerotic CV disease (ASCVD) risk prediction algorithm for the Asian population using SCORE2 data was presented. Long-term follow-up of patients enrolled in the CLEAR outcomes trial showed sustained and more significant ASCVD risk reduction with bempedoic acid in high-risk patients. Summary: The late-breaking clinical science at the 2023 congress of the ESC extends the known safety and efficacy data of a PCSK9i with the introduction of new drugs in this class. Using cumulative exposure to LDL-C rather than a single value will help clinicians tailor the LDL-C reduction strategy to individual risk and is an important step towards personalized medicine. [ABSTRACT FROM AUTHOR]

Purpose of Review: The focus of this article is to highlight the importance of the small GTPase, Ras-associated protein 1 (Rap1), in proprotein convertase subtilisin/kexin type 9 (PCSK9) regulation and atherosclerosis and type 2 diabetes etiology and discuss the potential therapeutic implications of targeting Rap1 in these disease areas. Review Findings: Cardiometabolic disease characterized by obesity, glucose intolerance, dyslipidemia, and atherosclerotic cardiovascular disease remain an important cause of mortality. Evidence using mouse models of obesity and insulin resistance indicates that Rap1 deficiency increases proatherogenic PCSK9 and low-density lipoprotein cholesterol levels and predisposes these mice to develop obesity- and statin-induced hyperglycemia, which highlights Rap1's role in cardiometabolic dysfunction. Rap1 may also contribute to cardiovascular disease through its effects on vascular wall cells involved in the atherosclerosis progression. Summary: Rap1 activation, specifically in the liver, could be beneficial in the prevention of cardiometabolic perturbations, including type 2 diabetes, hypercholesterolemia, and atherosclerosis. [ABSTRACT FROM AUTHOR]

Background: Proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates inflammatory response and CD4+ T cell differentiation in autoimmune diseases, while its clinical role in rheumatoid arthritis (RA) lacks sufficient evidence. Subsequently, this study intended to explore the vertical change of PCSK9, and its linkage with T helper (Th) cells, regulatory T (Treg) cells, clinical features, and treatment outcomes in RA patients. Methods: This multi-center, prospective, cohort study determined serum PCSK9 in 89 RA patients who received conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) and 50 healthy controls (HCs) after recruitment by enzyme-linked immunosorbent assay. For RA patients, serum PCSK9 was also determined at 6th week, 12th week, and 24th week; meanwhile, Th1, Th2, Th17, and Treg cells at baseline were determined through flow cytometry. Results: PCSK9 was increased in RA patients compared to HCs (median: 209.2 versus 122.0 ng/mL, P < 0.001). In RA patients, PCSK9 positively correlated with Th17 cells (P = 0.023) and Th17/Treg ratio (P = 0.018), but did not link with Th1 cells, Th2 cells, Th1/Th2 ratio, or Treg cells. Meanwhile, PCSK9 was not associated with any demographics and medication histories, while it positively correlated with C-reactive protein (P = 0.010), disease activity score in 28 joints (P = 0.009), physician's global assessment (P = 0.015), and clinical disease activity index (P = 0.040). Importantly, PCSK9 gradually reduced from baseline to 24th week; its decrement related to higher possibility of treatment response (P = 0.002), low disease activity (P = 0.001), and remission of csDMARDs (P = 0.012). Conclusion: Circulating PCSK9 shows the potency as a biomarker for disease management and treatment outcome prediction of csDMARDs in RA. [ABSTRACT FROM AUTHOR]

Pharmaceuticals and environmental contaminants contribute to hypercholesterolemia. Several chemicals known to cause hypercholesterolemia, activate pregnane X receptor (PXR). PXR is a nuclear receptor, classically identified as a sensor of chemical environment and regulator of detoxification processes. Later, PXR activation has been shown to disrupt metabolic functions such as lipid metabolism and recent findings have shown PXR activation to promote hypercholesterolemia through multiple mechanisms. Hypercholesterolemia is a major causative risk factor for atherosclerosis and greatly promotes global health burden. Metabolic disruption by PXR activating chemicals leading to hypercholesterolemia represents a novel toxicity pathway of concern and requires further attention. Therefore, we constructed an adverse outcome pathway (AOP) by collecting the available knowledge considering the molecular mechanisms for PXR-mediated hypercholesterolemia. AOPs are tools of modern toxicology for systematizing mechanistic knowledge to assist health risk assessment of chemicals. AOPs are formalized and structured linear concepts describing a link between molecular initiating event (MIE) and adverse outcome (AO). MIE and AO are connected via key events (KE) through key event relationships (KER). We present a plausible route of how PXR activation (MIE) leads to hypercholesterolemia (AO) through direct regulation of cholesterol synthesis and via activation of sterol regulatory element binding protein 2-pathway. [ABSTRACT FROM AUTHOR]

Background: Familial hypercholesterolemia (FH) is caused by pathogenic variants in low-density lipoprotein (LDL) receptor (LDLR) or its associated genes, including apolipoprotein B (APOB), proprotein convertase subtilisin/kexin type 9 (PCSK9), and LDLR adaptor protein 1 (LDLRAP1). However, approximately 40% of the FH patients clinically diagnosed (based on FH phenotypes) may not carry a causal variant in a FH-related gene. Variants located at 3' untranslated region (UTR) of FH-related genes could elucidate mechanisms involved in FH pathogenesis. This study used a computational approach to assess the effects of 3'UTR variants in FH-related genes on miRNAs molecular interactions and to explore the association of these variants with molecular diagnosis of FH. Methods and results: Exons and regulatory regions of FH-related genes were sequenced in 83 FH patients using an exon-target gene sequencing strategy. In silico prediction tools were used to study the effects of 3´UTR variants on interactions between miRNAs and target mRNAs. Pathogenic variants in FH-related genes (molecular diagnosis) were detected in 44.6% FH patients. Among 59 3'UTR variants identified, LDLR rs5742911 and PCSK9 rs17111557 were associated with molecular diagnosis of FH, whereas LDLR rs7258146 and rs7254521 and LDLRAP1 rs397860393 had an opposite effect (p < 0.05). 3´UTR variants in LDLR (rs5742911, rs7258146, rs7254521) and PCSK9 (rs17111557) disrupt interactions with several miRNAs, and more stable bindings were found with LDLR (miR-4435, miR-509-3 and miR-502) and PCSK9 (miR-4796). Conclusion: LDLR and PCSK9 3´UTR variants disturb miRNA:mRNA interactions that could affect gene expression and are potentially associated with molecular diagnosis of FH. [ABSTRACT FROM AUTHOR]

Purpose of Review: Familial hypercholesterolemia (FH) is a hereditary condition characterized by elevated levels of low-density lipoprotein cholesterol (LDL-C), which increases the risk of cardiovascular disease if left untreated. This review aims to discuss the role of bioinformatics tools in evaluating the pathogenicity of missense variants associated with FH. Specifically, it highlights the use of predictive models based on protein sequence, structure, evolutionary conservation, and other relevant features in identifying genetic variants within LDLR, APOB, and PCSK9 genes that contribute to FH. Recent Findings: In recent years, various bioinformatics tools have emerged as valuable resources for analyzing missense variants in FH-related genes. Tools such as REVEL, Varity, and CADD use diverse computational approaches to predict the impact of genetic variants on protein function. These tools consider factors such as sequence conservation, structural alterations, and receptor binding to aid in interpreting the pathogenicity of identified missense variants. While these predictive models offer valuable insights, the accuracy of predictions can vary, especially for proteins with unique characteristics that might not be well represented in the databases used for training. Summary: This review emphasizes the significance of utilizing bioinformatics tools for assessing the pathogenicity of FH-associated missense variants. Despite their contributions, a definitive diagnosis of a genetic variant necessitates functional validation through in vitro characterization or cascade screening. This step ensures the precise identification of FH-related variants, leading to more accurate diagnoses. Integrating genetic data with reliable bioinformatics predictions and functional validation can enhance our understanding of the genetic basis of FH, enabling improved diagnosis, risk stratification, and personalized treatment for affected individuals. The comprehensive approach outlined in this review promises to advance the management of this inherited disorder, potentially leading to better health outcomes for those affected by FH. [ABSTRACT FROM AUTHOR]

Background and aims: Low-density lipoprotein cholesterol (LDL-C) is the main therapeutic target in the treatment of hypercholesterolemia. Small interfering RNA (siRNA) inclisiran is a new drug, which targets PCSK9 mRNA in the liver, reducing concentrations of circulating LDL-C. In randomized trials, inclisiran demonstrated a substantial reduction in LDL-C. The German Inclisiran Network (GIN) aims to evaluate LDL-C reductions in a real-world cohort of patients treated with inclisiran in Germany. Methods: Patients who received inclisiran in 14 lipid clinics in Germany for elevated LDL-C levels between February 2021 and July 2022 were included in this analysis. We described baseline characteristics, individual LDL-C changes (%) and side effects in 153 patients 3 months (n = 153) and 9 months (n = 79) after inclisiran administration. Results: Since all patients were referred to specialized lipid clinics, only one-third were on statin therapy due to statin intolerance. The median LDL-C reduction was 35.5% at 3 months and 26.5% at 9 months. In patients previously treated with PCSK9 antibody (PCSK9-mAb), LDL-C reductions were less effective than in PCSK9-mAb-naïve patients (23.6% vs. 41.1% at 3 months). Concomitant statin treatment was associated with more effective LDL-C lowering. There was a high interindividual variability in LDL-C changes from baseline. Altogether, inclisiran was well-tolerated, and side effects were rare (5.9%). Conclusion: In this real-world patient population referred to German lipid clinics for elevated LDL-C levels, inclisiran demonstrated a high interindividual variability in LDL-C reductions. Further research is warranted to elucidate reasons for the interindividual variability in drug efficacy. [ABSTRACT FROM AUTHOR]

The liver, as a crucial metabolic organ, undergoes significant pathological changes during the aging process, which can have a profound impact on overall health. To gain a comprehensive understanding of these alterations, we employed data-driven approaches, along with biochemical methods, histology, and immunohistochemistry techniques, to systematically investigate the effects of aging on the liver. Our study utilized a well-established rat aging model provided by the National Institute of Aging. Systems biology approaches were used to analyze genome-wide transcriptomics data from liver samples obtained from young (4–5 months old) and aging (20–21 months old) Fischer 344 rats. Our findings revealed pathological changes occurring in various essential biological processes in aging livers. These included mitochondrial dysfunction, increased oxidative/nitrative stress, decreased NAD + content, impaired amino acid and protein synthesis, heightened inflammation, disrupted lipid metabolism, enhanced apoptosis, senescence, and fibrosis. These results were validated using independent datasets from both human and rat aging studies. Furthermore, by employing co-expression network analysis, we identified novel driver genes responsible for liver aging, confirmed our findings in human aging subjects, and pointed out the cellular localization of the driver genes using single-cell RNA-sequencing human data. Our study led to the discovery and validation of a liver-specific gene, proprotein convertase subtilisin/kexin type 9 (PCSK9), as a potential therapeutic target for mitigating the pathological processes associated with aging in the liver. This finding envisions new possibilities for developing interventions aimed to improve liver health during the aging process. [ABSTRACT FROM AUTHOR]

Purpose of Review: Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a central role in the metabolism of LDL receptors and mainly acts in the liver. However, there are accumulating data that PCSK9 involves in several functions in different organs beyond the liver. Herein we aimed to summarize the effects of PCSK9 in tissues other than the liver. Recent Findings: PCSK9 has crucial roles in heart, brain and kidney in addition to the cholesterol metabolism. Targeting PCSK9 for the treatment of hypercholesterolemia is effective in the prevention from cardiovascular diseases and PCSK9 inhibitors are getting to be administered in more cases. Therefore understanding the effects of PCSK9 in other tissues gained importance in the use of PCSK9 inhibitors era. Summary: PCSK9 participates in cardiac, renal, and neurologic functions however, current literature reveals that use of PSCSK9 inhibitors have beneficial or neutral effects on these organs. Inhibition of PCSK9 is assigned to be associated with new onset diabetes in experimental studies whereas real world data with PCSK9 inhibitors established no relationship between PCSK9 inhibitors and new onset diabetes. PCSK9 might be used as a target for the treatment of nephrotic syndrome and heart failure in the future. [ABSTRACT FROM AUTHOR]

To study the relationship of serum PCSK9 and disease activity and major adverse cardiovascular events (MACEs) in systemic lupus erythematosus (SLE). Consecutive patients who fulfilled ≥ 4 ACR criteria for SLE and consented for a biomarker study in 2009–2013 were included. Stored serum samples were assayed for PCSK9. PCSK9 levels were correlated with SLE disease activity scores. Patients were divided into two groups according to the median PCSK9 level and new MACEs over time were evaluated. The effect of PCSK9 level on MACEs and mortality was studied by Cox regression, adjusted for confounders. A total of 539 SLE patients were studied (93% women, age 41.9 ± 14.0 years). The median PCSK9 level at baseline was 220 ng/ml. Patients with higher PCSK9 (≥ 220 ng/ml; n = 269) had significantly higher SLE disease activity index (SLEDAI) than those with lower PCSK9 (< 220 ng/ml; n = 270). PCSK9 levels were significantly higher in patients with active renal than active non-renal SLE, which in turn were significantly higher than those with inactive SLE or healthy controls. PCSK9 level correlated with SLEDAI in the overall population (ρ = 0.30; p < 0.001). Over 91.3 ± 18.6 months, 29 patients developed 31 MACEs and 40 patients succumbed (25% for vascular events). The cumulative incidence of MACEs at 5 years was 4.8% in the higher PCSK9 and 1.1% in the lower PCSK9 group (HR2.51[1.11–5.70]; p = 0.03). Cox regression revealed higher PCSK9 was significantly associated with MACEs (HR1.003[1.000–1.005] per ng/ml; p = 0.02) independent of age, sex, renal function, baseline disease activity score, traditional atherosclerotic risk factors, antiphospholipid antibody and the use of aspirin/warfarin, statins and immunosuppressive drugs. PCSK9 level was also independently associated with all-cause (HR1.002[1.000–1.004] per ng/ml; p = 0.03) and vascular mortality (HR1.004[1.000–1.007]; p = 0.04). We concluded that serum PCSK9 level correlates with SLE disease activity. Higher serum PCSK9 levels are associated with increased risk of cardiovascular events and mortality in SLE. [ABSTRACT FROM AUTHOR]

Introduction: Evolocumab, a fully human proprotein convertase/subtilisin kexin type 9 inhibitor antibody, significantly lowers low-density lipoprotein cholesterol (LDL-C) in patients with type 2 diabetes mellitus and hyperlipidemia and mixed dyslipidemia. This 12-week study evaluated the efficacy and safety of evolocumab in Chinese patients with primary hypercholesterolemia and mixed dyslipidemia at different levels of cardiovascular disease risk. Methods: HUA TUO was a 12-week randomized, double-blind, placebo-controlled study. Chinese patients aged 18 years or older on stable optimized statin therapy were randomized 2:2:1:1 to receive evolocumab 140 mg every 2 weeks (Q2W), evolocumab 420 mg monthly (QM), or a matching placebo. The coprimary endpoints were percent change from baseline in LDL-C at the mean of weeks 10 and 12 and at week 12. Results: Overall, 241 randomized patients (mean [standard deviation] age, 60.2 [10.3] years) received evolocumab 140 mg Q2W (n = 79), evolocumab 420 mg QM (n = 80), placebo Q2W (n = 41), or placebo QM (n = 41). At weeks 10 and 12, the placebo-adjusted least-squares mean percent change from baseline in LDL-C for the evolocumab 140 mg Q2W group was − 70.7% (95% CI − 78.0% to − 63.5%); − 69.7% (95% CI − 76.5% to − 63.0%) for the evolocumab 420 mg QM group. Significant improvements in all other lipid parameters were observed with evolocumab. The patient incidence of treatment-emergent adverse events was similar between the treatment groups and across dosing regimens. Conclusion: In Chinese patients with primary hypercholesterolemia and mixed dyslipidemia, 12-week treatment with evolocumab significantly lowered LDL-C and other lipids, and was safe and well tolerated (NCT03433755). [ABSTRACT FROM AUTHOR]

Using multiple mouse models, we explored the impact of aging on the size and severity of atherosclerotic lesions. In young, middle-aged and old apolipoprotein E knockout mice (ApoE−/−) fed an atherogenic diet (AD) for 3–8 weeks, plaque/atheroma formation in the descending aorta and aortic root, and atheroma development in the carotid in response to partial carotid ligation (PCL) were assessed. Total and LDL cholesterol, and triglycerides were higher in old compared to both other age groups, regardless of AD duration. Aortic plaque burden increased with AD duration in all ages. The size and plaque morphology grade of aortic root atheromas was higher with age; however, there was no effect of age on the size or severity of carotid atheromas after PCL. We additionally induced hyperlipidemia in young and old C57BL/6 mice by adeno-associated virus mediated upregulation of LDL receptor regulator, Pcsk9, and 5 weeks of AD. Despite lower cholesterol in old compared to young Pcsk9 mice, there was a greater size and severity of aortic root atheromas in old mice. However, like the ApoE−/− mice, there was no effect of age on size or severity of PCL-induced carotid artery atheromas in Pcsk9 mice. Together, these results suggest that aging increases the size and severity of spontaneous aortic atheromas. [ABSTRACT FROM AUTHOR]

Ample evidence has pointed to a close link between cardiovascular diseases (CVD) and depression. Inflammatory pathways including the high-mobility-group-box-1 protein, receptor-for-advanced-glycation-end-products and toll-like-receptor-4 (HMGB1/RAGE/TLR4) and nucleotide-binding domain (NOD)–like receptor protein 3 (NLRP3) inflammasome pathways are thought to be crucial players in this link. Activation of these pathways ends by releasing of different inflammatory mediators involved in CVD and depression pathophysiology. In the brain, this inflammatory process enhanced indoleamine2,3-dioxygenase-1 (IDO-1) activation with subsequent alteration in kynurenine/tryptophan levels causing depression. Based on the favorable anti-inflammatory effects of Alirocumab, the proprotein-convertase-subtilisin/kexin-type-9 (PCSK9) inhibitor, used in different CVD, this study was designed to investigate its potential antidepressant effect. The behavioral and neurochemical effects of concomitant treatment of Alirocumab at doses of (4, 8 and 16 mg/kg/week subcutaneously) in Wistar rats exposed to chronic unpredictable mild stress (CUMS) for 6 weeks were assayed. Alirocumab prevented CUMS-induced depressive-like-behaviors exhibited in open-field and forced-swimming tests, and hypothalamus–pituitary–adrenal axis hyperactivity (adrenal gland weight and serum corticosterone). Alirocumab prevented CUMS-induced alteration in hippocampal kynurenine/tryptophan levels and pro-inflammatory cytokines tumor-necrosis-factor-alpha, interleukin-1beta (IL-1β), IL-2 and IL-6. Western blot and PCR analysis showed that Alirocumab favorably modulated the HMGB1/RAGE/TLR4 axis, nuclear-factor-kappa-beta, NLRP3 inflammasome complex and IDO-1 in the hippocampus of CUMS rats. These effects were correlated to the level of PCSK9 expression. The behavioral and biochemical findings indicated the potential antidepressant effect of PCSK9 inhibition by Alirocumab. [ABSTRACT FROM AUTHOR]

In recent years, the increase in available genetic information and a better understanding of the genetic bases of dyslipidemias has led to the identification of potential new avenues for therapies. Additionally, the development of new technologies has presented the key for developing novel therapeutic strategies targeting not only proteins (e.g., the monoclonal antibodies and vaccines) but also the transcripts (from antisense oligonucleotides (ASOs) to small interfering RNAs) or the genomic sequence (gene therapies). These pharmacological advances have led to successful therapeutic improvements, particularly in the cardiovascular arena because we are now able to treat rare, genetically driven, and previously untreatable conditions (e.g, familial hypertriglyceridemia or hyperchylomicronemia). In this review, the pre-clinical pharmacological development of the major biotechnological cholesterol lowering advances were discussed, describing facts, gaps, potential future steps forward, and therapeutic opportunities. [ABSTRACT FROM AUTHOR]

Endothelial dysfunction often accompanies sepsis. We aimed to explore the role of PCSK9 in septic endothelial dysfunction. Sepsis was induced by lipopolysaccharide (LPS) treatment of human umbilical vein endothelial cells (HUVECs) in vitro and cecal ligation and puncture (CLP) surgery in mice in vivo. Evolocumab (EVC) and Pep 2–8, PCSK9 inhibitors, were subsequently used to determine the role of PCSK9 in sepsis-induced endothelial dysfunction in vitro and in vivo, respectively. In addition, the TLR4 agonist, Kdo2-Lipid A ammonium (KLA), was used to determine the related mechanism. Protein expression of eNOS, VE-cadherin, PCSK9, TLR4, MyD88, p-p65, p65, NLRP3, ASC, and caspase-1 p20 in mice aortas and HUVECs was measured by western blotting, while mRNA expression of TNFα, IL-1β, and IL-18 was determined by qRT-PCR. The level of inflammatory cytokines of mouse aortas was visualized by immunohistochemistry. Vasodilation of the aorta was detected by vascular reactivity experiments. The 96-h survival rate after CLP was assessed. Our findings showed that the expression of eNOS and VE-cadherin decreased, and PCSK9 expression increased, in septic HUVECs or mice. Inhibition of PCSK9 increased eNOS and VE-cadherin expression. Activation of the TLR4/MyD88/NF-κB and NLRP3 pathways may be responsible for PCSK9-induced endothelial dysfunction in sepsis. Vascular reactivity tests and survival studies showed that inhibition of PCSK9 could prevent the decrease in endothelium-dependent vasodilation function and improve the survival rates of septic mice. In summary, our results suggested that increased PCSK9 expression during sepsis activated the TLR4/MyD88/NF-κB and NLRP3 pathways to induce inflammation, which resulted in vascular endothelial dysfunction and decreased survival rates. Thus, inhibition of PCSK9 may be a potential clinical therapeutic target to improve vascular endothelial function in sepsis. [ABSTRACT FROM AUTHOR]

Purpose: By-products from farmed fish contain large amounts of proteins and may be used for human consumption. The purpose of this study was to investigate cardiometabolic effects and metabolic tolerance in mice consuming fishmeal from salmon by-products, salmon filet or beef. Methods: Female C57BL/6J mice were fed chow, as a healthy reference group, or a high-fat diet for 10 weeks to induce obesity and glucose intolerance. Obese mice were subsequently given isocaloric diets containing 50% of the dietary protein from salmon fishmeal, salmon filet or beef for 10 weeks. Mice were subjected to metabolic phenotyping, which included measurements of body composition, energy metabolism in metabolic cages and glucose tolerance. Lipid content and markers of hepatic toxicity were determined in plasma and liver. Hepatic gene and protein expression was determined with RNA sequencing and immunoblotting. Results: Mice fed fishmeal, salmon filet or beef had similar food intake, energy consumption, body weight gain, adiposity, glucose tolerance and circulating levels of lipids and hepatic toxicity markers, such as p-ALT and p-AST. Fishmeal increased hepatic cholesterol levels by 35–36% as compared to salmon filet (p = 0.0001) and beef (p = 0.005). This was accompanied by repressed expression of genes involved in steroid and cholesterol metabolism and reduced levels of circulating Pcsk9. Conclusion: Salmon fishmeal was well tolerated, but increased hepatic cholesterol content. The high cholesterol content in fishmeal may be responsible for the effects on hepatic cholesterol metabolism. Before introducing fishmeal from salmon by-products as a dietary component, it may be advantageous to reduce the cholesterol content in fishmeal. [ABSTRACT FROM AUTHOR]

Purpose of Review: Since the clinical benefit of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors occurs in a setting of reducing low-density lipoprotein-cholesterol (LDL-C) to unprecedentedly low levels, it becomes of interest to investigate possible adverse effects pertaining to the risk of new-onset diabetes (NOD). Recent Findings: While safety results reported in either meta-analyses or cardiovascular outcome trials FOURIER (with evolocumab) and ODYSSEY (with alirocumab) did not rise the incidence of NOD, Mendelian randomization analyses were almost concordant in showing an increased risk of NOD. This evidence was in line with post-marketing safety reports highlighting that evolocumab and alirocumab were primarily related to mild hyperglycaemia rather than diabetes, with most of the hyperglycaemic events occurring during the first 6 months of treatment. Summary: Considering the different nature of genetic studies and of randomized controlled trials, with careful monitoring of patients, particularly in the earlier phases of treatment, and the identification of those more susceptible to develop NOD, treatment with PCSK9 inhibitors should be of minimal concern. [ABSTRACT FROM AUTHOR]

This study investigates the effect and mechanism of proprotein convertase subtilisin/Kexin type 9 (PCSK9) on myocardial ischemia–reperfusion injury (MIRI) and provides a reference for clinical prevention and treatment of acute myocardial infarction (AMI). We established a rat model of myocardial ischemia/reperfusion (I/R) and AC16 hypoxia/reoxygenation (H/R) model. A total of 48 adult 7-week-old male Sprague–Dawley rats were randomly assigned to three groups (n = 16): control, I/R, and I/R + SiRNA. In I/R and I/R + siRNA groups, myocardial ischemia was induced via occlusion of the left anterior descending branch (LAD) of the coronary artery in rats in I/R group for 30 min and reperfused for 3 days. To assess the myocardial injury, the rats were subjected to an electrocardiogram (ECG), cardiac function tests, cardiac enzymes analysis, and 2,3,5-triphenyl tetrazolium chloride (TTC)/Evan Blue (EB) staining. Meanwhile, differences in the expression of autophagy-level proteins and Bcl-2/adenovirus E1B 19-kDa interacting protein (Bnip3) signaling-related proteins were determined by protein blotting. In vitro and in vivo experimental studies revealed that siRNA knockdown of PCSK9 reduced the expression of autophagic protein Beclin-1, light chain 3 (LC3) compared to normal control-treated cells and control-operated groups. Simultaneously, the expression of Bnip3 pathway protein was downregulated. Furthermore, the PCSK9-mediated small interfering RNA (siRNA) group injected into the left ventricular wall significantly improved cardiac function and myocardial infarct size. In ischemic/hypoxic circumstances, PCSK9 expression was dramatically increased. PCSK9 knockdown alleviated MIRI via Bnip3-mediated autophagic pathway, inhibited inflammatory response, reduced myocardial infarct size, and protected cardiac function. [ABSTRACT FROM AUTHOR]

Purpose of Review: Since the discovery of PCSK9 in 2003, this proprotein convertase was shown to target specific receptors for degradation in endosomes/lysosomes, including LDLR and other family members and hence to enhance the levels of circulating LDL-cholesterol (LDLc). Accordingly, inhibitors of PCSK9, including monoclonal antibodies blocking its circulating activity and siRNA silencers of its hepatic expression, are now used in clinics worldwide to treat hypercholesterolemia patients effectively and safely in combination with statins and/or ezetimibe. These powerful treatments reduce the incidence of atherosclerosis by at least 20%. Since 2008, novel targets of PCSK9 began to be defined, thereby expanding its roles beyond LDLc regulation into the realm of inflammation, pathogen infections and cellular proliferation in various cancers and associated metastases. Recent Findings: Some pathogens such as dengue virus exploit the ability of PCSK9 to target the LDLR for degradation to enhance their ability to infect cells. Aside from increasing the degradation of the LDLR and its family members VLDLR, ApoER2 and LRP1, circulating PCSK9 also reduces the levels of other receptors such as CD36 (implicated in fatty acid uptake), oxidized LDLR receptor (that clears oxidized LDLc) as well as major histocompatibility class-I (MHC-I) receptors (implicated in the immune response to antigens). Thus, these novel targets provided links between PCSK9 and inflammation/atherosclerosis, viral infections and cancer/metastasis. The functional activities of PCSK9, accelerated the development of novel therapies to inhibit PCSK9 functions, including small molecular inhibitors, long-term vaccines, and possibly CRISPR-based silencing of hepatic expression of PCSK9. Summary: The future of inhibitors/silencers of PCSK9 function or expression looks bright, as these are expected to provide a modern armamentarium to treat various pathologies beyond hypercholesterolemia and its effects on atherosclerosis. [ABSTRACT FROM AUTHOR]

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Background: Dyslipidemia is a common finding in primary nephrotic syndrome (PNS). Serum PCSK9 level is also increased in PNS and is the main cause of dyslipidemia in such patients. There is a paucity of data on the relation between dyslipidemia and pathological types of PNS. We hypothesized that severity of dyslipidemia varies across different types of PNS, and this variation is due to differences in serum PCSK9 levels. Methods: Fifty patients recently diagnosed with PNS were included in this cross-sectional study. Serum PCSK9, albumin, creatinine, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), very low-density lipoprotein cholesterol (VLDL-C), triglycerides (TG), and 24-h urine protein were measured. Comparison of patients' characteristics between pathological types of PNS and correlations between serum PCSK9 and other parameters were assessed. Results: Serum PCSK9 levels were significantly higher in PNS patients compared with healthy individuals (314.58 ± 73.83 vs 253.42 ± 36.66 ng/ml, p < 0.001). No differences found between PNS types regarding serum levels of PCSK9 (p = 0.571), TC (p = 0.806), LDL-C (p = 0.950), HDL-C (p = 0.844), VLDL-C (p = 0.472), and TG (p = 0.969). Serum PCSK9 levels correlated significantly with TC (p < 0.001), LDL-C (p < 0.001), HDL-C (p = 0.003), VLDL-C (p = 0.008), TG (p = 0.005), 24-h urine protein (p = 0.005), and male sex (p = 0.014). Conclusion: The pathological type of PNS does not affect serum levels of PCSK9 and components of lipid profile. [ABSTRACT FROM AUTHOR]

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a member of the proprotein convertase family of proteins that activate other proteins in cells. Functionally, PCSK9 binds to the receptor of low-density lipoprotein particles (LDL) to regulate cholesterol metabolism and lipoprotein homeostasis in human body. PCSK9 inhibition is a novel pharmacological strategy to control hypercholesterolemia and cardiovascular diseases. Recently accumulating evidence realizes that PCSK9 possesses other roles in cells, such as regulation of tissue inflammatory response, intratumoral immune cell infiltration, and tumor progression. This review discussed the advancement of PCSK9 research on its role and underlying mechanisms in tumor development and progression. For example, PCSK9 inhibition could attenuate progression of breast cancer, glioma, colon tumor, hepatocellular cancer, prostate cancer, and lung adenocarcinoma and promote apoptosis of glioma, prostate cancer, and hepatocellular cancer cells. PCSK9 deficiency could reduce liver metastasis of B16F1 melanoma cells by lowering the circulating cholesterol levels. PCSK9 gene knockdown substantially attenuated mouse tumor growth in vivo by activation of cytotoxic T cells, although PCSK9 knockdown had no effect on morphology and growth rate of different mouse cancer cell lines in vitro. PCSK9 inhibition thus can be used to control human cancers. Future preclinical and clinical studies are warranted to define anti-tumor activity of PCSK9 inhibition. [ABSTRACT FROM AUTHOR]

Purpose: Metformin (MF) intake associates with reduced levels of circulating low-density lipoprotein-cholesterol (LDL-C). This has been attributed to the activation of AMPK, which differentially regulates the expression of multiple genes involved in cholesterol synthesis and trafficking. However, the exact mechanism underlying the LDL-C lowering effect of MF remains ambiguous. Methods: MF-treated Hep-G2 and HuH7 cells were evaluated for cell viability and the expression status of key lipid metabolism-related genes along with LDL-C uptake efficiency. Results: MF treatment resulted in decreased expression and secretion of PCSK9, increased expression of LDLR and enhanced LDL-C uptake in hepatocytes. It also resulted in increased expression of activated AMPK (p-AMPK) and decreased expression of SREBP2 and HNF-1α proteins. Transcriptomic analysis of MF-treated Hep-G2 cells confirmed these findings and showed that other key lipid metabolism-related genes including those that encode apolipoproteins (APOB, APOC2, APOC3 and APOE), MTTP and LIPC are downregulated. Lastly, MF treatment associated with reduced HMG-CoA reductase expression and activity. Conclusions: These findings suggest that MF treatment reduces circulating LDL-C levels by suppressing PCSK9 expression and enhancing LDLR expression; hence the potential therapeutic utility of MF in hypercholesterolemia. [ABSTRACT FROM AUTHOR]

Background: Proprotein convertase subtilisin kexin 9 (PCSK9) is a serin protease synthesized mainly in the liver that binds the receptor of low-density lipoprotein and promotes its degradation in lysosomes. PCSK9 is considered a promising target for the development of new therapies for the treatment of hypercholesterolemia and related cardiovascular diseases. Extracellular vesicles represent a heterogeneous population of vesicles, ranging in size between 0.05 and 1 μm involved in numerous pathophysiological processes, including blood coagulation. We investigated whether PCSK9 stimulation induces the release of procoagulant extracellular vesicles from human mononuclear cells (PBMCs) and THP-1 cells. Methods and results: PBMCs and THP-1 cells were stimulated whit PCSK9, the generation of EV was assessed by the prothrombinase assay and by cytofluorimetric analysis. EV-associated tissue factor activity was assessed by a one-stage clotting assay. PCSK9 induced an increase in extracellular generation by PBMCs and THP-1 cells as well as an increase in extracellular vesicle-associated tissue factor. Pre-treatment with inhibitors of the toll like receptor, TLR4 (C34), and of NF-κB signaling (BAY 11-7082), downregulated PCSK9-induced extracellular vesicle generation and of extracellular- bound tissue factor. Similar effect was obtained by an anti-PCSK9 human-monoclonal antibody. Conclusions: PCSK9-mediated generation of procoagulant EV could contribute to increase the prothrombotic status in patients with cardiovascular diseases. [ABSTRACT FROM AUTHOR]

We explore the interaction between estrogen and PCSK9 and their collective impact on lipid metabolism, especially concerning the regulation of low-density lipoprotein receptor levels. Utilizing both animal and cellular models, including ovariectomized mice and HepG2 cell lines, we demonstrate that estrogen deficiency leads to a disruption in lipid metabolism, characterized by elevated levels of total cholesterol and LDL-C. The study commences with mice undergoing ovariectomy, followed by a diet regimen comprising either high-fat diet or normal feed for a four-week duration. Key assessments include analyzing lipid metabolism, measuring PCSK9 levels in the bloodstream, and evaluating hepatic low-density lipoprotein receptor expression. We will also conduct correlation analyses to understand the relationship between PCSK9 and various lipid profiles. Further, a subset of ovariectomized mice on high-fat diet will undergo treatment with either estrogen or PCSK9 inhibitor for two weeks, with a subsequent re-evaluation of the earlier mentioned parameters. Our findings reveal that estrogen inhibits PCSK9-mediated degradation of low-density lipoprotein receptor, a process crucial for maintaining lipid homeostasis. Through a series of experiments, including immunohistochemistry and western blot analysis, we establish that PCSK9 is involved in lipid metabolism disorders caused by estrogen deficiency and that estrogen regulates PCSK9 and low-density lipoprotein receptor at post-transcriptional level. The study provides a mechanism for the involvement of PCSK9 in elucidating the disorders of lipid metabolism caused by estrogen deficiency due to perimenopause and ovarian decline. [ABSTRACT FROM AUTHOR]

Introduction: Proprotein convertase subtilisin/kexin 9 inhibitors (PCSK9i) are monoclonal antibodies that lower lipid levels. Although several cardiovascular outcome trials reported the effectiveness of PCSK9i, the evidence on cost-effectiveness is mixed. We systematically reviewed the evidence and synthesized incremental net benefit (INB) to quantify pooled cost-effectiveness. Methods: We systematically searched for full economic evaluation studies reporting outcomes of PCSK9i compared with other lipid-lowering pharmacotherapies. We searched PubMed, Embase, Scopus, and Tufts Registry for eligible studies up to August 2021, adhering to preferred reporting items for systematic reviews and meta-analyses guidelines. We pooled INB in US$ with a 95% confidence interval using a random-effects model. We assessed heterogeneity using the Cochran Q test and I2 statistics. We used the modified economic evaluations bias (ECOBIAS) checklist to evaluate the quality of selected studies. Results: Twenty-three studies were eligible, mainly from high-income countries (HIC). The pooled INB (INBp) of PCSK9i versus other lipid-lowering pharmacotherapies were estimated from n = 24 comparisons, with high heterogeneity (I2 = 99.99). The INBp (95% CI) was $ − 78,207 (− 120,422; − 35,993) or € − 52,526 (− 80,879; − 24,174) (conversion factor 1 US$ = 0.67€) which shows that PCSK9i was not significantly cost-effective when compared to other standard therapies. On subgroup analysis PCSK9i was significantly not cost-effective [$ − 23,672 (− 24,061; − 23,282)] compared to other lipid-lowering pharmacotherapies in HICs, upper-middle-income countries [$ − 158,412 (− 241,738; − 75,086)] or when the target population was CVD [$ − 109,343 (− 158,968; − 59,717)]; and for treatment subgroup: against placebo or no treatment [$ − 79,018 (− 79,649; − 78,388 PCSK9)] and standard statin therapies [$ − 131,833 (− 173,449; − 90,216)]. The sensitivity analysis revealed that the findings are not robust for HICs and the treatment subgroups. Conclusion: PCSK9 inhibitors are not cost-effective compared to other lipid-lowering pharmacotherapies in HICs. Further, current pieces of evidence are predominantly from HICs with largely lacking evidence from other economies. Prospero registration: ID CRD42020206043. [ABSTRACT FROM AUTHOR]

The aim of this work was to study the association of potential biomarkers with fast aortic stenosis (AS) progression. Patients with moderate-to-severe AS were classified as very fast progressors (VFP) if exhibited an annualized change in peak velocity (aΔVmax) ≥0.45m/s/year and/or in aortic valve area (aΔAVA) ≥−0.2cm2/year. Respective cut-off values of ≥0.3m/s/year and ≥−0.1cm2/year defined fast progressors (FP), whereas the remaining patients were non-fast progressors (non-FP). Baseline markers of lipid metabolism, inflammation, and cardiac overload were determined. Two hundred and nine patients (97 non-FP, 38 FP, and 74 VFP) were included. PCSK9 levels were significantly associated with VFP (OR 1.014 [95%CI 1.005-1.024], for every 10 ng/mL), as were active smoking (OR 3.48) and body mass index (BMI, OR 1.09), with an AUC of 0.704 for the model. PCSK9 levels, active smoking, and BMI were associated with very fast AS progression in our series, suggesting that inflammation and calcification participate in disease progression. [ABSTRACT FROM AUTHOR]

Rationale: It is controversial whether dyslipidemia induced by antipsychotics in schizophrenia patients is due to weight gain or direct effects of drug treatment. However, recent evidence showed that olanzapine can cause acute dyslipidemia independent of weight change, and the underlying mechanism remains unclear. Objective: To study the role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in olanzapine-induced dyslipidemia, we analyzed in schizophrenic patients and in experimental models involving mice and cells to understand the mechanism. Methods: Disturbances in lipid homeostasis caused by 8-week olanzapine treatment were prospectively evaluated in first-episode schizophrenic patients. Additionally, mice were administered olanzapine for 5 or 8 weeks to delineate liver actions for PCSK9 contributing to olanzapine-induced dyslipidemia. Results: Olanzapine directly affected lipid metabolism, suggesting dyslipidemia is independent of weight gain in schizophrenia patients. Olanzapine administration significantly increased plasma PCSK9, which was positively correlated with the increment in low-density lipoprotein cholesterol (LDL-C) (r=0.77, p<0.001). Increased expression of PCSK9 in liver tissue of olanzapine-treated mice occurred prior to olanzapine-induced LDL-C abnormality. Hepatic sterol regulatory element binding protein-2 (SREBP-2) protein levels increased in mice treated with olanzapine but largely declined in olanzapine (10μM) treated HepG2 cells, which suggested high concentration of olanzapine-induced PCSK9 increase was not SREBP-2-dependent. However, expressions of sterol regulatory element binding protein-1c (SREBP-1c) significantly increased in the higher dose treated groups, which was consistent with PCSK9 increases. Activation of SREBP-1c after high-dose olanzapine treatment promotes PSCK9 expression, and consequently the degradation of low-density lipoprotein receptors results in LDL-C increase. Conclusions: Lipid disturbances caused by olanzapine are independent of weight gain. The study explored the relationship between SREBP-1c and PCSK9 in regulating lipoprotein metabolism after olanzapine treatment in vitro and in vivo. Further exploration of olanzapine-induced PCSK9 regulatory mechanisms may help identify control points for inhibition of olanzapine-mediated dyslipidemia. [ABSTRACT FROM AUTHOR]

Purpose of Review: Familial hypercholesterolemia (FH) is a monogenic disorder characterized by high plasma levels of low-density lipoprotein cholesterol (LDL-C) since birth and a high risk of premature cardiovascular disease. The genetic defect is carried in only one allele in heterozygous FH (HeFH) or in both in the most severe homozygous FH (HoFH). Current guidelines recommend to reduce substantially LDL-C levels in these high-risk patients, with the need to use association therapy combining agents with different mechanisms of action. As most cases of FH are attributable to mutations in the gene encoding the low-density lipoprotein receptor (LDLR), statins, even in combination with ezetimibe, are less effective in reducing LDL-C plasma levels in FH patients, who require a more intensive approach with additional lipid-lowering agents. Additional targets playing key roles in regulating LDL-C levels are represented by PCSK9 and ANGPTL3. Recent Findings: Two monoclonal antibodies (mAbs) targeting PCSK9, evolocumab and alirocumab, significantly reduce LDL-C levels in HeFH patients. In patients with HoFH, the efficacy of mAbs to PCSK9 is strictly related to the presence of a residual LDLR activity; thus, patients carrying null mutations do not respond to the therapy with these mAbs, whereas some effects can be appreciated in HoFH bearing defective mutations. Conversely, evinacumab, the mAb targeting ANGPTL3, is highly effective in reducing LDL-C levels even in HoFH patients carrying null LDLR mutations, thanks to its LDLR-independent mechanism of action. Summary: Monoclonal antibodies inhibiting PCSK9 have shown a robust effect in FH patients presenting a residual LDLR activity, while ANGPTL3 inhibitors appear to be promising even in patients carrying null LDLR mutations. [ABSTRACT FROM AUTHOR]

Purpose: AT04A and AT06A are two AFFITOPE® peptide vaccine candidates being developed for the treatment of hypercholesterolemia by inducing proprotein convertase subtilisin/kexin type 9 (PCSK9)-specific antibodies. This study aimed to investigate safety, tolerability, antibody development, and reduction of low-density lipoprotein cholesterol (LDLc) following four subcutaneous immunizations. Methods: This phase I, single-blind, randomized, placebo-controlled study was conducted in a total of 72 healthy subjects with a mean fasting LDLc level at baseline of 117.1 mg/dL (range 77–196 mg/dL). Each cohort enrolled 24 subjects to receive three priming immunizations at weeks 0, 4, and 8 and to receive a single booster immunization at week 60 of either AT04A, AT06A, or placebo. In addition to safety (primary objective), the antigenic peptide- and PCSK9-specific antibody response and the impact on LDLc were evaluated over a period of 90 weeks. Results: The most common systemic treatment-related adverse events (AEs) reported were fatigue, headache, and myalgia in 75% of subjects in the AT06A group and 58% and 46% of subjects in the placebo and AT04A groups, respectively. Injection site reactions (ISR) representing 63% of all treatment-emergent adverse events (TEAEs), were transient and mostly of mild or moderate intensity and rarely severe (3%). Both active treatments triggered a robust, long-lasting antibody response towards the antigenic peptides used for immunization that optimally cross-reacted with the target epitope on PCSK9. In the AT04A group, a reduction in serum LDLc was observed with a mean peak reduction of 11.2% and 13.3% from baseline compared to placebo at week 20 and 70 respectively, and over the whole study period, the mean LDLc reduction for the AT04A group vs. placebo was −7.2% (95% CI [−10.4 to −3.9], P < 0.0001). In this group, PCSK9 target epitope titers above 50 were associated with clinically relevant LDLc reductions with an individual maximal decrease of 39%. Conclusions: Although both AT04A and AT06 were safe and immunogenic, only AT04A demonstrated significant LDLc-lowering activity, justifying further development. Trial registration: EudraCT: 2015-001719-11. ClinicalTrials.gov Identifier: NCT02508896. [ABSTRACT FROM AUTHOR]

Purpose: Recent guidelines recommend further reduction of low-density lipoprotein cholesterol (LDL-C) in high-risk populations. The use of proprotein convertase subtilisin/kexin type-9 inhibitors (PCSK9i) enables many patients to achieve profound reduction in LDL-C. However, in patients with low cholesterol, the commonly used Friedewald equation tends to underestimate LDL-C, which may result in undertreatment. We aimed to compare Friedewald LDL-C estimation with the more novel Martin/Hopkins method in PCSK9i-treated patients achieving low LDL-C. Methods: We investigated high-risk patients treated by PCSK9i in whom Friedewald LDL-C levels were < 70 mg/dL and triglycerides ≤ 300 mg/dL. LDL-C was additionally assessed by the Martin/Hopkins method. The compatibility between estimations was evaluated using methods of concordance and reclassification between LDL-C categories (< 25, 25–40, 40–55, 55–70 mg/dL) and according to triglyceride strata. Results: Mean age was 65 ± 10 years. The correlation coefficient between LDL-C estimations was r = 0.898. Martin/Hopkins reclassified 269 of the 608 patients (44%) to a higher LDL-C category, with 14% of the patients reaching LDL-C > 70 mg/dL. Of the 390 patients achieving Friedewald LDL-C < 55 mg/dL, 113 (29%) were estimated to have LDL-C ≥ 55 mg/dL by the Martin/Hopkins equation. The magnitude of discordance between LDL-C estimates was more pronounced in hypertriglyceridemic patients in whom LDL-C reclassification from < 55 to ≥ 55 mg/dL was observed in 48%. Conclusions: In real-world practice of high-risk patients achieving low LDL-C under PCSK9i, Martin/Hopkins algorithm displayed significant proportion of LDL-C upward discordance compared to the Friedewald equation, particularly observed in patients with elevated triglycerides, identifying patients that may need treatment intensification. [ABSTRACT FROM AUTHOR]

Purpose of Review: Elevation in apolipoprotein B-containing lipoproteins in the blood is a cause of atherosclerosis. Statins have changed the preventive cardiology scenario, and more recently monoclonal proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors were added as robust agents to further reduce pro-atherogenic lipoproteins and therefore prevent cardiovascular events. However, despite this many dyslipidemic individuals persist with inadequate LDL-C levels and still at risk. The purpose of this review was to discuss current status and describe advances in therapies beyond statins and monoclonal PCSK9 inhibitors. Recent Findings: Ezetimibe and lomitapide have been used for many years to further reduce LDL-C and longer term data reinforce their safety. Bempedoic acid, an inhibitor of adenosine triphosphate-citrate lyase, has been shown to add LDL-C reduction on top of statins and ezetimibe, furthermore it may be an alternative for statin intolerant patients. Inclisiran is a small interfering ribonucleic acid inhibitor that reduces the hepatic production of PCSK9 that induces robust LDL-C lowering, similar to monoclonal antibodies, with the advantage of 2 or 3 injections per year. So far, no safety signs were seen with its use. Evinacumab, a monoclonal antibody that binds angiopoietin-like protein 3 (ANGPTL3), induces robust LDL-C lowering in either homozygous familial hypercholesterolemia or severe hypercholesterolemia patients with good tolerability. Summary: Many high-risk individuals persist with elevated LDL-C, newer medications further lower LDL-C on top of standard lipid-lowering therapies and are well tolerated. Ongoing clinical trials may prove if these novel medications will reduce cardiovascular events with safety. [ABSTRACT FROM AUTHOR]

Monoclonal antibodies (mAbs) are widely employed as invaluable therapeutics for a vast number of human disorders. Several approaches have been introduced for the improvement of mAb production in Chinese hamster ovary (CHO) cells due to the increasing demand for these products. In this regard, various chromatin-modifying elements such as insulators have been incorporated in the expression vectors to augment mAb expression. In this study, human gamma-satellite insulator containing vectors were utilized for the expression of an anti-proprotein convertase subtilisin/kexin type 9 (PCSK9) mAb in CHO-K1 cells. To this aim, dual expression vectors encoding the antibody light chain (LC) and heavy chain (HC) with or without the insulator element were constructed, and mAb expression was evaluated in transient and stable expression. Based on the results, mAb expression significantly increased in the stable cell pool, and clonal cells developed using the human gamma-satellite insulator. In contrast, transient antibody expression was not affected by the insulator element. Finally, the enhancement of LC and HC mRNA levels was found in the insulator containing stable cell pools using the quantitative real-time-polymerase chain reaction (qRT-PCR). Our findings showed the positive effect of the human gamma-satellite insulator on the stable expression of an anti-PCSK9 immunoglobulin G1 (IgG1) mAb in CHO-K1 cells using dual expression vectors. [ABSTRACT FROM AUTHOR]

PCSK9 inhibitors lower low-density lipoprotein cholesterol (LDL-C) and reduce cardiovascular events. The clinical benefits presumably result from favorable effects on atherosclerotic plaques. Lipid-core and plaque inflammation have been recognized as main determinants of risk for plaque rupture and cardiovascular events. Both can be noninvasively assessed with carotid MRI. We studied if PCSK9 inhibition with alirocumab induces regression in lipid-core or plaque inflammation within 6 months as measured by MRI. Patients with non-calcified carotid plaque(s) and baseline LDL-C ≥ 70 mg/dl, who were statin-intolerant or taking a low-dose statin (≤ 10 mg per day of atorvastatin or an equivalent), received subcutaneous alirocumab 150 mg every 2 weeks. Carotid MRI was performed at baseline and 6 months after treatment, including pre- and post-contrast images for measuring percent lipid-core volume (%LC) and dynamic contrast-enhanced images for measuring microvessel leakiness (Ktrans), a marker of inflammation. Twenty-eight patients completed the study (69 ± 9 years; 64% male). Alirocumab led to significant changes in LDL-C (p < 0.001) and high-density lipoprotein cholesterol (HDL-C) (p = 0.003). At 6 months, there was a significant reduction in %LC (mean: − 2.1% [− 3.5, − 0.7], p = 0.005; a 17% reduction from baseline of 9.9%) without significant changes in lumen/wall area or in the inflammatory index Ktrans. Carotid plaque lipid content was reduced by 17% after 6 months of PCSK9 inhibition with alirocumab. This was seen before observable changes in lumen or wall areas, which supports pursing plaque lipid content as a more sensitive marker of therapeutic response compared to lumen or wall areas in future technical developments and serial studies. [ABSTRACT FROM AUTHOR]

Purpose: Our group has developed a therapeutic vaccine targeting proprotein convertase subtilisin/kexin type 9 (PCSK9), named PCSK9Qβ-003. In this study, we investigated the potential effectiveness of the PCSK9Qβ-003 vaccine on atherosclerosis. Methods: Male ApoE−/− mice were randomly assigned to three groups: a phosphate-buffered saline (PBS) group, Qβ virus-like particles (VLP) group, and PCSK9Qβ-003 vaccine group. Mice in the PCSK9Qβ-003 group were injected with the PCSK9Qβ-003 vaccine four times (100 μg/time) over a period of 18 weeks. The effects of the vaccine on atherosclerotic plaque, cholesterol transport, inflammation and apoptosis were investigated. Results: The PCSK9Qβ-003 vaccine obviously decreased total cholesterol and low-density lipoprotein cholesterol in ApoE−/− mice. Compared with the other groups, the PCSK9Qβ-003 vaccine significantly reduced the lesion area and promoted the stability of atherosclerotic plaque. The vaccine regulated cholesterol transport in the aorta of ApoE−/− mice by up-regulating the expression level of liver X receptor α and ATP binding cassette transporter A1. Additionally, macrophage infiltration and expression of monocyte chemoattractant protein-1 and tumor necrosis factor-α were significantly decreased in the mice administered the PCSK9Qβ-003 vaccine. The vaccine also markedly reduced apoptosis in the lesion area of the aorta in ApoE−/− mice. Conclusions: The results demonstrated that the PCSK9Qβ-003 vaccine attenuated the progression of atherosclerosis by modulating reverse cholesterol transport and inhibiting inflammation infiltration and apoptosis, which may provide a novel therapeutic approach for atherosclerosis and greatly improve treatment compliance among patients. [ABSTRACT FROM AUTHOR]

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a central role in cholesterol homeostasis in humans as a major regulator of LDLR levels. PCSK9 is an intriguing protease in that it does not act by proteolysis but by preventing LDLR recirculation from endosomes to the plasma membrane. This, and the inexistence of any other proteolytic substrate but itself could suggest that PCSK9 is an exquisite example of evolutionary fine-tuning. However, the gene has been lost in several mammalian species, and null alleles are present (albeit at low frequencies) in some human populations without apparently deleterious health effects, raising the possibility that the PCSK9 may have become dispensable in the mammalian lineage. To address this issue, we systematically recovered, assembled, corrected, annotated and analysed publicly available PCSK9 sequences for 420 eutherian species to determine the distribution, frequencies, mechanisms and timing of PCSK9 pseudogenization events, as well as the evolutionary pressures underlying the preservation or loss of the gene. We found a dramatic difference in the patterns of PCSK9 retention and loss between Euarchontoglires—where there is strong pressure for gene preservation—and Laurasiatheria, where multiple independent events have led to PCSK9 loss in most species. These results suggest that there is a fundamental difference in the regulation of cholesterol metabolism between Euarchontoglires and Laurasiatheria, which in turn has important implications for the use of Laurasiatheria species (e.g. pigs) as animal models of human cholesterol-related diseases. [ABSTRACT FROM AUTHOR]

Despite progress in both primary and secondary prevention, cardiovascular diseases (CVD) are still the largest group of ailments contributing to morbidity and mortality worldwide. Atherosclerotic changes, the primary pathological substrate for CVD, are closely related to hypercholesterolemia. Therefore, the treatment of hypercholesterolemia is a key therapeutic strategy for CVD management. Statins, as the gold standard in the treatment of hypercholesterolemia, have shown enhanced cardiac outcomes in many randomized clinical trials. However, often despite the maximum allowed and tolerated dosage of statins, we are not able to reach the target cholesterol levels, and thus patients persist at an increased cardiovascular risk. Recently, most of the large clinical studies in the field of preventive cardiology have focused on proprotein convertase subtilisin kexin type 9 (PCSK9) and its activity regulation. PCSK9 plays an essential role in the metabolism of LDL particles by inhibiting LDL receptor recirculation to the cell surface. Recent studies have shown that inhibition of PCSK9 by the administration of monoclonal antibodies is capable of significantly reducing LDL levels (up to an additional 60%) as well as reducing the incidence of CVD. However, this treatment procedure of administering the anti-PCSK9 antibodies, most frequently two times a month, has its limitations in terms of time, patient adherence, and nevertheless cost. Administration of active vaccination instead of passive immunization with anti-PCSK9 antibodies may be an effective way of controlling blood cholesterol levels. However, clinical data, as well as human testing, are still inadequate. This work aims to provide an overview of PCSK9 vaccines and their potential clinical benefit. [ABSTRACT FROM AUTHOR]

Proprotein convertase subtilisin/Kexin type 9 (PCSK9) and pyroptosis both play important roles in myocardial infarction. This study was designed to test the hypothesis that PCSK9 regulates pyroptosis in cardiomyocytes during chronic myocardial ischemia. Primary cardiomyocytes were isolated from WT and PCSK9−/− mice. HL-1 cardiomyocytes were used to set up PCSK9-deficient (PCSK9−/−) and PCSK9-upregulated (PCSK9CRISPRa) cardiomyocyte cell line with CRISPR/Cas9 knockout or activation plasmid. Additional studies were performed with chronic myocardial ischemia in WT and PCSK9−/− mice. We observed that PCSK9 initiates mitochondrial DNA (mtDNA) damage, activates NLRP3 inflammasome signaling (NLRP3, ASC, Caspase-1, IL-1β, and IL-18), and subsequently induces Caspase-1-dependent pyroptosis. There was an intense expression of PCSK9 and pyroptosis marker, GSDMD-NT, in the zone bordering the infarct area. PCSK9−/− significantly suppressed expression of NLRP3 inflammasome signaling, GSDMD-NT, and LDH release. Furthermore, serum levels of PCSK9, NLPR3 inflammasome signaling, and pyroptosis (GSDMD and LDH release) were significantly elevated in patients with chronic myocardial ischemia as compared to those in age-matched healthy subjects. Human hearts with recent infarcts also showed high expression of PCSK9 and GSDMD-NT in the border zone similar to that in the infarcted mouse heart. These observations provide compelling evidence for the role of PCSK9 in regulating Caspase-1-dependent pyroptosis via mtDNA damage and may qualify pro-inflammatory cytokines and pyroptosis as potential targets to treat PCSK9-related cardiovascular diseases. [ABSTRACT FROM AUTHOR]