Around 40% of the US population and 1 in 6 individuals worldwide have obesity, with the incidence surging globally1,2. Various dietary interventions, including carbohydrate, fat and, more recently, amino acid restriction, have been explored to combat this epidemic3-6. Here we investigated the impact of removing individual amino acids on the weight profiles of mice. We show that conditional cysteine restriction resulted in the most substantial weight loss when compared to essential amino acid restriction, amounting to 30% within 1 week, which was readily reversed. We found that cysteine deficiency activated the integrated stress response and oxidative stress response, which amplify each other, leading to the induction of GDF15 and FGF21, partly explaining the phenotype7-9. Notably, we observed lower levels of tissue coenzyme A (CoA), which has been considered to be extremely stable10, resulting in reduced mitochondrial functionality and metabolic rewiring. This results in energetically inefficient anaerobic glycolysis and defective tricarboxylic acid cycle, with sustained urinary excretion of pyruvate, orotate, citrate, α-ketoglutarate, nitrogen-rich compounds and amino acids. In summary, our investigation reveals that cysteine restriction, by depleting GSH and CoA, exerts a maximal impact on weight loss, metabolism and stress signalling compared with other amino acid restrictions. These findings suggest strategies for addressing a range of metabolic diseases and the growing obesity crisis.

Hypercholesterolemia is one of the major risk factors for cardiovascular diseases. While probiotics and prebiotics show cholesterol-lowering potential, current evidence suggests limited efficacy when used alone. This study investigated the synergistic effects of oat β-glucan (OBG) and Lacticaseibacillus paracasei K56 (L. paracasei K56) against diet-induced hypercholesterolemia in mice. Hypercholesterolemic mice were treated for 12 weeks with atorvastatin (5 mg/kg/day), L. paracasei K56 (5 × 109 CFU/kg), OBG (1 g/kg/day) or their combination. The combination treatment demonstrated superior efficacy, reducing total cholesterol (TC) by 41.19 ± 7.13 % (vs model group) and low-density lipoprotein cholesterol (LDL-C) by 37.47 ± 6.55 % (vs model group), with 24.37 ± 9.18 % (vs OBG group) and 15.10 ± 10.30 % (vs K56 group) greater TC reduction. Liver histopathology showed 3.7-fold reduction in steatosis scores versus model group. Mechanistically, compared with the model group, the combination upregulated hepatic CYP7A1/CYP27A1 expression by 5.75 ± 0.51-fold and 2.34 ± 0.21-fold respectively, increased fecal bile acids and enriched bile acid producing bacteria. In summary, L. paracasei K56 and OBG synergistically regulate gut microbiota and bile acid metabolism, promoting the conversion of cholesterol into bile acids, thereby alleviating hypercholesterolemia in mice.

Naturally existing enzymes have been adapted for a variety of molecular technologies, with enhancements or modifications to the enzymes introduced to improve the desired function; however, it is difficult to engineer variants with enhanced activity while maintaining specificity. Here we engineer the compact Obligate Mobile Element Guided Activity (OMEGA) RNA-guided endonuclease IscB and its guiding RNA (ωRNA) by combining ortholog screening, structure-guided protein domain design and RNA engineering, and deep learning-based structure prediction to generate an improved variant, NovaIscB. We show that the compact NovaIscB achieves up to 40% indel activity (~100-fold improvement over wild-type OgeuIscB) on the human genome with improved specificity relative to existing IscBs. We further show that NovaIscB can be fused with a methyltransferase to create a programmable transcriptional repressor, OMEGAoff, that is compact enough to be packaged in a single adeno-associated virus vector for persistent in vivo gene repression. This study highlights the power of combining natural diversity with protein engineering to design enhanced enzymes for molecular biology applications.

Excess cholesterol accumulation contributes to fibrogenesis in metabolic dysfunction-associated steatohepatitis (MASH), but how hepatic cholesterol metabolism becomes dysregulated in MASH is not completely understood. We show that human fibrotic MASH livers have decreased EH-domain-binding protein 1 (EHBP1), a genome-wide association study (GWAS) locus associated with low-density lipoprotein (LDL) cholesterol, and that EHBP1 loss- and gain-of-function increase and decrease MASH fibrosis in mice, respectively. Mechanistic studies reveal that EHBP1 promotes sortilin-mediated PCSK9 secretion, leading to LDL receptor (LDLR) degradation, decreased LDL uptake, and reduced TAZ, a fibrogenic effector. At a cellular level, EHBP1 deficiency affects the intracellular localization of retromer, a protein complex required for sortilin stabilization. Our therapeutic approach to stabilizing retromer is effective in mitigating MASH fibrosis. Moreover, we show that the tumor necrosis factor alpha (TNF-α)/peroxisome proliferator-activated receptor alpha (PPARα) pathway suppresses EHBP1 in MASH. These data not only provide mechanistic insights into the role of EHBP1 in cholesterol metabolism and MASH fibrosis but also elucidate an interplay between inflammation and EHBP1-mediated cholesterol metabolism.

Although attractive for relevance to real-world scenarios, real-world data (RWD) is typically used for drug repurposing and not therapeutic target discovery. Repurposing studies have identified few effective options in neurological diseases such as the rare disease, amyotrophic lateral sclerosis (ALS), which has no disease-modifying treatments available. We previously reclassified drugs by their simulated effects on proteins downstream of drug targets and observed class-level effects in the EHR, implicating the downstream protein as the source of the effect. Here, we developed a novel ALS-focused network medicine model using data from patient samples, the public domain, and consortia. With this model, we simulated drug effects on ALS and measured class effects on overall survival in retrospective EHR studies. We observed an increased but non-significant risk of death for patients taking drugs with complement system proteins downstream of their targets and experimentally validated drug effects on complement activation. We repeated this for six protein classes, three of which, including multiple chemokine receptors, were associated with a significantly increased risk for death, suggesting that targeting proteins such as CXCR5, CXCR3, chemokine signaling generally, or neuropeptide Y (NPY) could be advantageous therapeutic targets for these patients. We expanded our analysis to the neuroinflammatory condition, myasthenia gravis, and neurodegenerative disease, Parkinson's, and recovered similar effect sizes. We demonstrated the utility of network medicine for testing novel therapeutic effects using RWD and believe this approach may accelerate target discovery in neurological diseases, addressing the critical need for new therapeutic options.

Proprotein-converting enzyme subtilisin-kexin type 9 (PCSK9) inhibitors act more promptly and efficiently than statins and reduce the risk of cardiovascular events in patients with acute coronary syndrome (ACS). This study aimed to assess the short-term effects of perioperative administration of a single-dose PCSK9 inhibitor in patients with ACS.

This study included 789 consecutive patients undergoing percutaneous coronary intervention (PCI) for ACS. The primary clinical endpoint was the occurrence of major adverse cardiovascular events (MACEs) within one month, including cardiac death, non-fatal myocardial infarction, unanticipated revascularization, stroke, stent thrombosis, and rehospitalization for ischemic causes or heart failure.

PCSK9 inhibitors were administered to 201 of 789 patients. MACEs occurred in eight patients (4.0%) in the treated group and 60 patients (10.2%) in the non-treated group for one month (hazard ratio 0.38, 95% confidence interval 0.18 to 0.80, p = 0.010). The benefit of PCSK9 inhibitors in terms of MACEs was greater in the subgroup of patients treated more than 1 hour before PCI than in the subgroup treated less than 1 hour before PCI or treated after PCI and in the non-treated group.

In patients undergoing PCI for ACS, the risk of MACEs was lower in those treated with perioperative single-dose PCSK9 inhibitors than in those in the untreated group. This benefit was especially noticeable in the subgroups treated > 1 hour before PCI than in those treated less than 1 hour before PCI or after PCI, regardless of the clinical presentation of ACS.

Saffron (Crocus sativus L.) has long been used in Ayurveda, Iranian, and Chinese traditional medicine as a natural remedy for hypercholesterolemia, obesity, and liver disorders though its therapeutic mechanism remains unclear.

This study explores the mechanism by which saffron extract (SE), crocin (CN), and crocetin (CR) mitigate high fat diet (HFD) induced hypercholesterolemia and hepatic inflammation in C57BL/6 mice, focusing on their inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9).

C57BL/6 mice (N = 10/group) were fed either a, normal diet, HFD, or HFD supplemented with SE, CN, CR, or atorvastatin for 12 weeks. Plasma lipids and inflammatory markers were measured. Histopathological changes were assessed via H&E and Sudan black staining. Gene expression was analyzed using qRT-PCR, and ligand-protein interactions were studied using molecular docking, simulation, and thermophoresis.

HFD-fed mice exhibited dyslipidemia, liver damage, and inflammation, which SE, CN, and CR significantly improved. Treatments reduced cholesterol, triglycerides, and reactive oxygen species, reversed fatty liver degeneration, and downregulated PCSK9 and sortilin expression while upregulating LDLR. They suppressed transcription factors SREBP-1C and SREBP-2 and reduced inflammatory markers, including TNF-α, while increasing IL-10 expression. CR reduced plasma PCSK9 secretion by 39.9 % (p < 0.05). Docking and simulation studies confirmed the strong binding potential of CR and CN to PCSK9.

Saffron and its active components (CN and CR) are novel natural PCSK9 inhibitors that effectively ameliorate hypercholesterolemia by modulating sortilin, LDLR and SREBP-2 pathway, potentially opening the way for developing new therapeutic approaches for managing cholesterol related disorders.

Complex diseases may share portions of their polygenic architectures which can be leveraged to identify drug targets with low off-target potential or repurposable candidates. However, the literature lacks methods which can make these inferences at scale using publicly available data.

We introduce a Bayesian model to estimate the polygenic structure of a trait using only gene-based association test statistics from GWAS summary data and returns gene-level posterior risk probabilities (PRPs). PRPs were used to infer shared polygenicity between 496 trait pairs and we introduce measures that can prioritize drug targets with low off-target effects or drug repurposing potential.

Across 32 traits, we estimated that 69.5 to 97.5% of disease-associated genes are shared between multiple traits, and the estimated number of druggable genes that were only associated with a single disease ranged from 1 (multiple sclerosis) to 59 (schizophrenia). Estimating the shared genetic architecture of ALS with all other traits identified the KIT gene as a potentially harmful drug target because of its deleterious association with triglycerides, but also identified TBK1 and SCN11B as putatively safer because of their non-association with any of the other 31 traits. We additionally found 21 genes which are candidate repourposable targets for Alzheimer's disease (AD) (e.g., PLEKHA1, PPIB) and 5 for ALS (e.g., GAK, DGKQ).

The sets of candidate drug targets which have limited off-target potential are generally smaller compared to the sets of pleiotropic and putatively repurposable drug targets, but both represent promising directions for future experimental studies.

The low-density lipoprotein receptor (LDLR) is integral to cholesterol metabolism and cardiovascular health. Enhancing LDLR expression is a promising strategy for treating hyperlipidemia and reducing the risk of atherosclerosis. However, current LDLR reporter systems have limitations in detecting both transcriptional and translational regulation. To address this, we developed a novel dual-reporter LDLR system incorporating Enhanced Green Fluorescent Protein (EGFP) and Gaussia luciferase (Gluc) to enable precise monitoring of LDLR expression and function.

A CRISPR/Cas9-mediated knock-in strategy was used to integrate EGFP and Gluc upstream of the stop codon located in exon 18 of the LDLR gene in HEK293 cells. The dual-reporter system allows real-time visualization of LDLR expression via EGFP fluorescence and quantitative assessment through secreted Gluc activity. The system was validated using western blotting, immunofluorescence, and functional assays, including DiI-LDL uptake and drug response analyses with statins and PCSK9 inhibitors.

The established LDLR-EGFP-Gluc knock-in cell line faithfully recapitulates endogenous LDLR expression and function. EGFP fluorescence accurately reflects LDLR expression dynamics, while Gluc activity provides a highly sensitive and quantitative readout. Functional assays confirmed that LDLR expression responds appropriately to statins and PCSK9 inhibitors. Additionally, screening for transcriptional regulators identified FOXP3 and CREB as novel modulators of LDLR expression, with CREB-mediated regulation involving the sterol regulatory element-binding protein 2 (SREBP2) pathway.

This dual-reporter system enables complementary monitoring of LDLR dynamics, providing enhanced sensitivity, accuracy, and versatility for studying LDLR regulation and function, as well as facilitating drug discovery targeting hyperlipidemia and cardiovascular diseases.

Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) have potential applications in cancer therapy and as cholesterol-lowering treatments. The impact of PCSK9 suppression on both tumor growth and metastasis, as well as the management of diabetes, has been demonstrated. PCSK9i can also enhance outcomes and reduce cardiovascular (CV) events in individuals with a history of such events. In this review, we provide insights into the pharmacology, safety, and impact of PCSK9i. We highlight cutting-edge investigations, the development of innovative PCSK9i-based products, and a more comprehensive understanding of the potential effects of these drugs on cancer, diabetes, and CV and cerebrovascular diseases.

The objective of this study is to assess the relative efficacy of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, such as alirocumab, evolocumab, and inclisiran, in conjunction with potent statins like atorvastatin and rosuvastatin, in patients presenting with hyperlipidemia or heightened cardiovascular risk attributable to elevated low-density lipoprotein cholesterol (LDL-C).

A systematic search was conducted across databases including PubMed, Embase, and the Cochrane Library to explore lipid-lowering therapies in hyperlipidemia from their inception to 7 November 2023. A network meta-analysis (NMA) was conducted via Stata 17 software, with two authors independently conducting the search, screening, and data abstraction.

A total of 68 clinical studies involving 21,288 patients with hyperlipidemia were incorporated into the NMA. PSCK9 inhibitors and potent statins significantly reduced LDL-C levels from baseline vs. placebo regardless of background therapy. Regarding the efficacy of lipid reduction, four principal medications were evaluated: evolocumab and atorvastatin [mean standard deviation (MD) -3.41, 95% CI -4.81 to -2.00] and evolocumab with rosuvastatin (MD -3.44, 95% CI -5.10 to -1.78) vs. placebo; alirocumab combined with rosuvastatin (MD -2.91, 95% CI -3.95 to -1.88) and alirocumab with atorvastatin (MD -2.90, 95% CI -3.97 to -1.84) vs. placebo. Meanwhile, compared with placebo, evolocumab (MD -1.89, 95% CI -2.27 to -1.50), alirocumab (MD -1.83, 95% CI -2.09 to -1.57), rosuvastatin (MD -1.93, 95% CI -2.30 to -1.56), inclisiran (MD -1.68, 95% CI -2.10 to -1.27), and atorvastatin (MD -1.68, 95% CI -2.04 to -1.31) could also play a role in the treatment of LDL-C reduction. Moreover, the incidence of adverse events (AEs) was similar to that observed in the control group, which included both placebo and potent statin groups, with no significant differences identified in our study (P > 0.05).

The combination of PCSK9 inhibitors with robust statins like rosuvastatin and atorvastatin markedly decreases LDL-C levels in patients with hyperlipidemia when compared to placebo or monotherapy. Notably, the pairing of evolocumab and atorvastatin exhibited exceptional efficacy in this investigation. In the interim, the combination of PCSK9 inhibitors and potent statins demonstrates a notable safety profile when contrasted with the control group.

Dysfunctional cholesterol metabolism is highly prevalent in patients with hyperuricemia. Both uric acid and cholesterol are independent risk factors for atherosclerosis, contributing to an increased incidence of cardiovascular disease in hyperuricemia. Investigating the pathological mechanisms underlying cholesterol metabolism dysfunction in hyperuricemia is essential. This study identified adenosine and inosine, two major purine metabolites, as key regulators of cholesterol biosynthesis. These metabolites upregulate 3-hydroxy-3-methylglutaryl-CoA. Further mechanistic studies revealed that adenosine/inosine up-regulated the expression of 3-hydroxy-3-methylglutaryl-CoA by activating adenosine A2A receptor via the Srebp-2/Creb axis in hyperuricemia. Additionally, we found that taurine deficiency contributes to cholesterol metabolism dysfunction in hyperuricemia. Taurine administration in hyperuricemia mice significantly reduced cholesterol elevation by inhibiting adenosine A2A receptor. This study provides a promising strategy for treating comorbid hypercholesterolemia and hyperuricemia.

Breast cancer (BC) has become the most prevalent cancer worldwide, and further research is being conducted to deepen our understanding of its pathogenesis and treatment. Lipid metabolism disorder is a significant alteration in cancer cells, and the investigation into the role of Interleukin-17 (IL-17) in malignant tumors has emerged as a research focus in recent years. Thus, exploring changes in lipid metabolism and inflammatory factors in BC cells is crucial in identifying potential therapeutic targets. This article summarizes the progress made in the research on the main low-density cholesterol (LDL) transporter and IL-17 in lipid metabolism, and their potential involvement in the development of BC. The article aims to establish a theoretical foundation for the development of BC-related therapies.

PCSK9 is a serine protease that regulates plasma levels of low-density lipoprotein (LDL) and cholesterol by mediating the endolysosomal degradation of LDL receptor (LDLR) in the liver. When PCSK9 functions unchecked, it leads to increased degradation of LDLR, resulting in elevated circulatory levels of LDL and cholesterol. This dysregulation contributes to lipid and cholesterol metabolism abnormalities, foam cell formation, and the development of various diseases, including cardiovascular disease (CVD), viral infections, cancer, and sepsis. Emerging clinical and experimental evidence highlights an imperative role for PCSK9 in metabolic anomalies such as hypercholesterolemia and hyperlipidemia, as well as inflammation, and disturbances in mitochondrial homeostasis. Moreover, metabolic hormones - including insulin, glucagon, adipokines, natriuretic peptides, and sex steroids - regulate the expression and circulatory levels of PCSK9, thus influencing cardiovascular and metabolic functions. In this comprehensive review, we aim to elucidate the regulatory role of PCSK9 in lipid and cholesterol metabolism, pathophysiology of diseases such as CVD, infections, cancer, and sepsis, as well as its pharmaceutical and non-pharmaceutical targeting for therapeutic management of these conditions.

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

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

Identifying patients at risk for metastatic relapse is a critical medical need. We identified a common missense germline variant in proprotein convertase subtilisin/kexin type 9 (PCSK9) (rs562556, V474I) that is associated with reduced survival in multiple breast cancer patient cohorts. Genetic modeling of this gain-of-function single-nucleotide variant in mice revealed that it causally promotes breast cancer metastasis. Conversely, host PCSK9 deletion reduced metastatic colonization in multiple breast cancer models. Host PCSK9 promoted metastatic initiation events in lung and enhanced metastatic proliferative competence by targeting tumoral low-density lipoprotein receptor related protein 1 (LRP1) receptors, which repressed metastasis-promoting genes XAF1 and USP18. Antibody-mediated therapeutic inhibition of PCSK9 suppressed breast cancer metastasis in multiple models. In a large Swedish early-stage breast cancer cohort, rs562556 homozygotes had a 22% risk of distant metastatic relapse at 15 years, whereas non-homozygotes had a 2% risk. Our findings reveal that a commonly inherited genetic alteration governs breast cancer metastasis and predicts survival-uncovering a hereditary basis underlying breast cancer metastasis.

Identifying factors that affect treatment response is a central objective of clinical research, yet the role of common genetic variation remains largely unknown. Here, we develop a framework to study the genetic architecture of response to commonly prescribed drugs in large biobanks. We quantify treatment response heritability for statins, metformin, warfarin, and methotrexate in the UK Biobank. We find that genetic variation modifies the primary effect of statins on LDL cholesterol (9% heritable) as well as their side effects on hemoglobin A1c and blood glucose (10% and 11% heritable, respectively). We identify dozens of genes that modify drug response, which we replicate in a retrospective pharmacogenomic study. Finally, we find that polygenic score (PGS) accuracy varies up to 2-fold depending on treatment status, showing that standard PGSs are likely to underperform in clinical contexts.

Background/Objectives: This study investigated the potential of green algae-derived carotenoids as natural inhibitors of the proprotein convertase subtilisin/kexin type 9 (PCSK9), a key regulator of cholesterol metabolism. PCSK9 promotes the degradation of low-density lipoprotein receptors (LDLR), thereby increasing blood cholesterol levels and elevating the risk of cardiovascular diseases. Methods/Results: We screened the pharmacophore fit score of 27 carotenoids with PCSK9 and identified 14 that were analyzed for binding affinity and molecular interactions. Astaxanthin, siphonaxanthin, and prasinoxanthin were identified as the top candidates, demonstrating strong binding affinity (-10.5, -10.3, and -9.4 Kcal/mol, respectively) and stable interactions with several known key residues within the active site of PCSK9, including Pro-331, Arg-357, Cys-358, Val-359, Asp-360, Ile-416, Leu-436, Thr-437, Pro-438, Leu-440, Arg-458, Val-460, Trp-461, Arg-476, Cys-477, Ala-478, Ala-649, Val-650, and Asp-651. Density functional theory analysis confirmed the stability of astaxanthin and its favorable electronic properties, suggesting its potential as an effective inhibitor. Molecular dynamics simulations of the PCSK9-astaxanthin complex revealed sustained structural stability and key interactions critical for maintaining the functional integrity of the protein. Conclusions: These findings provide evidence that specific carotenoids, particularly astaxanthin, may offer a cost-effective alternative to existing PCSK9 inhibitors, providing a potential approach for managing cholesterol levels and reducing cardiovascular risk. Pre-clinical and clinical validations are required to confirm the therapeutic potential of these compounds.

PCSK9 inhibitors are a novel class of medications that lower LDL cholesterol (LDL-C) by increasing LDL receptor activity, promoting clearance of LDL-C from the bloodstream. Over the years, PCSK9 inhibitors have been explored as adjunct therapies to statins or as monotherapy in high-risk cardiovascular patients.

This review aims to provide an updated perspective on PCSK9 inhibitors, assessing their clinical efficacy, safety, and significance, especially in light of recent clinical trials.

The review examines the role of PCSK9 in cholesterol regulation and summarizes the results of major cardiovascular trials, including FOURIER, SPIRE-1, SPIRE-2, and ODYSSEY Outcomes. It also discusses emerging treatments like small interfering RNA (siRNA) therapies and evaluates PCSK9 inhibitor effects on LDL-C and lipoprotein(a) levels.

Clinical trials have shown PCSK9 inhibitors reduce LDL-C by up to 60%. In the FOURIER trial, evolocumab reduced LDL-C by 59% and major cardiovascular events by 15%-20%. The SPIRE-2 trial, despite early termination, showed a 21% risk reduction in the primary composite endpoint with bococizumab. The ODYSSEY Outcomes trial reported a 57% LDL-C reduction with alirocumab, alongside a 15% reduction in adverse events. Emerging treatments like Inclisiran offer long-term LDL-C control with fewer doses. PCSK9 inhibitors are generally well-tolerated, with the most common side effect being injection site reactions.

PCSK9 inhibitors significantly lower LDL-C and reduce cardiovascular events, offering promising therapies for high-risk patients, including those with familial hypercholesterolemia (FH) and those who cannot tolerate statins. Future research will focus on optimizing these inhibitors, integrating complementary therapies, and exploring gene-editing technologies to improve patient outcomes.

The present study intended to divulge the potential role of garlic-derived organosulfur compounds (OSCs) in targeting PCSK-9 and averting its interaction with the EGF-A portion of LDL-R via in-vitro and in-silico analysis. Our in-silico screening data showed that 3-(Propylsulfinyl)-L-alanine (PSA), S-Ethyl-L-cysteine (SEC), alliin, and S-Allyl-L-cysteine (SAC) exhibited higher binding energy (-7.05, -7.00, -6.65, and -6.31 Kcal/mol, respectively) against PCSK-9, among other selected OSCs. Further, the protein-protein interaction study of PCSK-9-OSCs-complex with EGF-A demonstrated a similar binding pattern with E-total values ranging from -430.01 to -405.6 Kcal/mol. These results were further validated via in-vitro analysis which showed that SEC, SAC, and diallyl trisulphide (DAT) exhibited the lowest IC50 values of 4.70, 5.26, and 5.29 µg/mL, respectively. In conclusion, the presented data illustrated that SEC, SAC, and DAT were the best inhibitors of PCSK-9 activity and may have the potential to improve the LDL-R function and lower the circulatory LDL-C level.

Sepsis is a life-threatening organ dysfunction syndrome caused by a dysregulated host response to infection that has a high mortality rate. Proprotein convertase subtilisin kexin 9 (PCSK9) is a serine protease secreted by the liver. Its binding to the low-density lipoprotein (LDL) receptor enhances its degradation, causing an increase in LDL levels in the blood. Objectives: Administering a PCSK9 inhibitor leading to an increase in lipid uptake by the liver may positively affect septic patients due to the increased removal of endotoxins. Methods: This preliminary study aimed to examine the safety of PCSK9 inhibitor use in septic and septic shock patients. We treated five septic patients in the intensive care unit with 300 mg of alirocumab following serious adverse events for 28 days. Results: Four of our patients did not experience any adverse events, and all of them survived. One patient died after discharge from the intensive care unit, and this death was presumably not related to the study drug. The patients rapidly recovered from the inflammatory stage of sepsis. Conclusions: Alirocumab appears safe in severe sepsis and septic shock patients. The outcome data are promising. Only a basic safety profile can be assessed based on this pilot study. Further study with a PCSK-9 inhibitor in septic or septic shock patients is required to further determine its benefit in ICU patients.

We investigated the potential of proprotein convertase subtilisin/kexin type 9 (PCSK9) antibodies to restore macrophage cholesterol efflux in subjects with heterozygous familial hypercholesterolemia (FH) and to enhance the macrophage-specific reverse cholesterol transport pathway in mice. Analyses of macrophage-derived cholesterol distribution of plasma from FH patients revealed that low-density lipoprotein (LDL) particles contained less, and high-density lipoprotein particles contained more radiolabeled cholesterol after treatment with either PCSK9 inhibitor. PCSK9 antibodies facilitated the transfer of macrophage-derived cholesterol and LDL-derived cholesterol to feces exclusively in heterozygous LDL receptor-deficient mice expressing human APOB100. PCSK9 inhibitors act as positive regulators of the macrophage-specific reverse cholesterol transport pathway in individuals with heterozygous FH.

Familial hypercholesterolemia (FH) is a genetic disorder that affects 1 in 300 people, leading to high cholesterol levels and significantly increased cardiovascular risk. The limitations of existing FH treatments underscore the need for innovative therapeutics, and gene therapy offers a promising alternative to address FH more effectively. In this review, we survey approved gene therapy drugs first and then delve into the landscape of gene addition, gene inactivation, and gene editing therapies for hypercholesterolemia, highlighting both approved interventions and those in various stages of development. We also discussed recent advancements in gene editing tools that are essential for their application in gene therapy. Safety considerations inherent to gene therapy are also discussed, emphasizing the importance of mitigating potential risks associated with such treatments. Overall, this review highlights the progress and prospects of gene therapies for FH treatments, underscoring their potential to revolutionize the management of this prevalent and challenging condition.

The RNA-guided clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12b system represents the third family of CRISPR-Cas systems that are harnessed for genome editing. However, only a few nucleases have demonstrated activity in human cells, and their in vivo therapeutic potential remains uncertain. In this study, a green fluorescent protein (GFP)-activation assay is conducted to screen a panel of 15 Cas12b orthologs, and four of them exhibited editing activity in mammalian cells. Particularly noteworthy is the NiCas12b derived from Nitrospira sp., which recognizes a "TTN" protospacer adjacent motif (PAM) and facilitates efficient genome editing in various cell lines. Importantly, NiCas12b also exhibits a high degree of specificity, rendering it suitable for therapeutic applications. As proof of concept, the adeno-associated virus (AAV) is employed to introduce NiCas12b to target the cholesterol regulatory gene proprotein convertase subtilisin/ kexin type 9 (Pcsk9) in the mouse liver. After 4 weeks of injections, an impressive is observed over 16.0% insertion/deletion (indel) efficiency, resulting in a significant reduction in serum cholesterol levels. NiCas12b provides a novel option for both basic research and clinical applications.

This study aimed to investigate the potential roles of proprotein convertase subtilisin/ kexin type 9 (PCSK9) and apelin in the etiology of fibromyalgia syndrome (FS).

The retrospective study was conducted between May 2022 and February 2023. Fifty-eight female FS patients (mean age: 45.2±9.9 years; range, 25 to 66 years) and 30 age- and body mass index-matched control subjects (mean age: 43.1±9.9 years; range, 26 to 67 years) were included in the study. Apelin and PCSK9 levels of all individuals were measured using appropriate methods.

The levels of PCSK9 (173.2±62.2 vs. 75.1±44.1, p<0.001) and apelin (354.6±195.5 vs. 229.0±83.2, p<0.001) were significantly higher in patients with FS compared to the control group. A positive correlation was found between PCSK9 and apelin levels and various measures, including the Fibromyalgia Impact Questionnaire (FIQ), Symptom Severity Scale (SSS), Pittsburgh Sleep Quality Index (PSQI), and Beck Depression Inventory (BDI). Additionally, there was a positive correlation between apelin levels and FIQ, SSS, PSQI, Beck Anxiety Inventory, and BDI scores. The optimal cutoff value for PCSK9 in predicting FS was 110.0 ng/mL, with a sensitivity of 84.5% and specificity of 83.9% (area under the curve [AUC]=0.920, 95% confidence interval [CI]: 0.852-0.987, p<0.001). For apelin, the optimal cutoff value for predicting FS was 258.8 ng/L, with a sensitivity of 63.8% and specificity of 64.5% (AUC=0.732, 95% CI: 0.623-0.840, p<0.001).

Our findings suggest that PCSK9 may play a role in FS etiology and potentially contribute to oxidative stress. Increased apelin levels may be a compensatory response to high oxidative stress, possibly leading to hyperalgesia. Both PCSK9 and apelin can be predictive markers for FS.

Neuroendocrine neoplasms (NENs) are a heterogeneous group of malignancies originating from cells with a neuroendocrine phenotype. The complex relationship between lipid metabolism and cancer is gaining interest and a potential anti-cancer effect of lipid lowering agents is being considered. This review aims to discuss the current understanding and treatment of dyslipidaemia in NENs, focusing on the role of lipid lowering agents, including new therapeutic approaches, and future perspectives as possible tool in cancer prevention and tumor-growth control.

We performed an electronic-based search using PubMed updated until December 2023, summarizing the available evidence both in basic and clinical research about lipid lowering agents in NENs.

Dyslipidemia is an important aspect to be considered in NENs management, although randomized studies specifically addressing this topic are lacking, unlike other cancer types. Available data mainly regard statins, and in vitro studies have demonstrated direct antitumor effects, including antiproliferative effects in some cancers, supporting possible pleiotropic effects also in NENs, but data remain conflicting. Ezetimibe, omega 3-fatty acids, fibrates and inhibitors of proprotein convertase subtilisin/kexin type 9 (PCSK9) may enhance the regulation of lipid homeostasis, as demonstrated in other cancers.

Targeting dyslipidemia in NENs should be part of the multidisciplinary management and an integrated approach may be the best option for both metabolic and tumor control. Whether lipid lowering agents may directly contribute to tumor control remains to be confirmed with specific studies, focusing on association with other metabolic risk, disease stage and primary site.

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.

Forty percent of the US population and 1 in 6 individuals worldwide are obese, and the incidence of this disease is surging globally1,2. Various dietary interventions, including carbohydrate and fat restriction, and more recently amino acid restriction, have been explored to combat this epidemic3-6. We sought to investigate the impact of removing individual amino acids on the weight profiles of mice. Compared to essential amino acid restriction, induction of conditional cysteine restriction resulted in the most dramatic weight loss, amounting to 20% within 3 days and 30% within one week, which was readily reversed. This weight loss occurred despite the presence of substantial cysteine reserves stored in glutathione (GSH) across various tissues7. Further analysis demonstrated that the weight reduction primarily stemmed from an increase in the utilization of fat mass, while locomotion, circadian rhythm and histological appearance of multiple other tissues remained largely unaffected. Cysteine deficiency activated the integrated stress response (ISR) and NRF2-mediated oxidative stress response (OSR), which amplify each other, leading to the induction of GDF15 and FGF21, hormones associated with increased lipolysis, energy homeostasis and food aversion8-10. We additionally observed rapid tissue coenzyme A (CoA) depletion, resulting in energetically inefficient anaerobic glycolysis and TCA cycle, with sustained urinary excretion of pyruvate, orotate, citrate, α-ketoglutarate, nitrogen rich compounds and amino acids. In summary, our investigation highlights that cysteine restriction, by depleting GSH and CoA, exerts a maximal impact on weight loss, metabolism, and stress signaling compared to other amino acid restrictions. These findings may pave the way for innovative strategies for addressing a range of metabolic diseases and the growing obesity crisis.

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.

Glucagon's ability to promote hepatic glucose production has been known for over a century, with initial observations touting this hormone as a diabetogenic agent. However, glucagon receptor agonism [when balanced with an incretin, including glucagon-like peptide 1 (GLP-1) to dampen glucose excursions] is now being developed as a promising therapeutic target in the treatment of metabolic diseases, like metabolic dysfunction-associated steatotic disease/metabolic dysfunction-associated steatohepatitis (MASLD/MASH), and may also have benefit for obesity and chronic kidney disease. Conventionally regarded as the opposing tag-team partner of the anabolic mediator insulin, glucagon is gradually emerging as more than just a "catabolic hormone." Glucagon action on glucose homeostasis within the liver has been well characterized. However, growing evidence, in part thanks to new and sensitive "omics" technologies, has implicated glucagon as more than just a "glucose liberator." Elucidation of glucagon's capacity to increase fatty acid oxidation while attenuating endogenous lipid synthesis speaks to the dichotomous nature of the hormone. Furthermore, glucagon action is not limited to just glucose homeostasis and lipid metabolism, as traditionally reported. Glucagon plays key regulatory roles in hepatic amino acid and ketone body metabolism, as well as mitochondrial turnover and function, indicating broader glucagon signaling consequences for metabolic homeostasis mediated by the liver. Here we examine the broadening role of glucagon signaling within the hepatocyte and question the current dogma, to appreciate glucagon as more than just that "catabolic hormone."

Familial hypobetalipoproteinemia (FHBL) 1 is a rare genetic disorder with an autosomal codominant mode of inheritance and is caused by defects in the apolipoprotein (apo) B (APOB) gene that disable lipoprotein formation. ApoB proteins are required for the formation of very low-density lipoproteins (VLDLs), chylomicrons, and their metabolites. VLDLs transport cholesterol and triglycerides from the liver to the peripheral tissues, whereas chylomicrons transport absorbed lipids and fat-soluble vitamins from the intestine. Homozygous or compound heterozygotes of FHBL1 (HoFHBL1) are extremely rare, and defects in APOB impair VLDL and chylomicron secretion, which result in marked hypolipidemia with malabsorption of fat and fat-soluble vitamins, leading to various complications such as growth disorders, acanthocytosis, retinitis pigmentosa, and neuropathy. Heterozygotes of FHBL1 are relatively common and are generally asymptomatic, except for moderate hypolipidemia and possible hepatic steatosis. If left untreated, HoFHBL1 can cause severe complications and disabilities that are pathologically and phenotypically similar to abetalipoproteinemia (ABL) (an autosomal recessive disorder) caused by mutations in the microsomal triglyceride transfer protein (MTTP) gene. Although HoFHBL1 and ABL cannot be distinguished from the clinical manifestations and laboratory findings of the proband, moderate hypolipidemia in first-degree relatives may help diagnose HoFHBL1. There is currently no specific treatment for HoFHBL1. Palliative therapy including high-dose fat-soluble vitamin supplementation may prevent or delay complications. Registry research on HoFHBL1 is currently ongoing to better understand the disease burden and unmet needs of this life-threatening disease with few therapeutic options.

The degradation of low-density lipoprotein receptor (LDLR) is induced by proprotein convertase subtilisin/kexin type 9 (PCSK9), resulting in elevated plasma concentrations of LDL cholesterol. Therefore, inhibiting the interactions between PCSK9 and LDLR is a desirable therapeutic goal for managing hypercholesterolemia. Aptamers, which are RNA or single-stranded DNA sequences, can recognize their targets based on their secondary structure. Aptamers exhibit high selectivity and affinity for binding to target molecules. The systematic evolution of ligands by exponential enrichment (SELEX), a combination of biological approaches, is used to screen most aptamers in vitro. Due to their unique advantages, aptamers have garnered significant interest since their discovery and have found extensive applications in various fields. Aptamers have been increasingly utilized in the development of biosensors for sensitive detection of pathogens, analytes, toxins, drug residues, and malignant cells. Furthermore, similar to monoclonal antibodies, aptamers can serve as therapeutic tools. Unlike certain protein therapeutics, aptamers do not elicit antibody responses, and their modified sugars at the 2'-positions generally prevent toll-like receptor-mediated innate immune responses. The focus of this review is on aptamer-based targeting of PCSK9 and the application of aptamers both as biosensors and therapeutic agents.

The protein PCSK9 (proprotein convertase subtilisin/Kexin type 9) negatively regulates the recycling of LDLR (low-density lipoprotein receptor), leading to an elevated plasma level of LDL. Inhibition of PCSK9-LDLR interaction has emerged as a promising therapeutic strategy to manage hypercholesterolemia. However, the large interaction surface area between PCSK9 and LDLR makes it challenging to identify a small molecule competitive inhibitor. An alternative strategy would be to identify distal cryptic sites as targets for allosteric inhibitors that can remotely modulate PCSK9-LDLR interaction. Using several microseconds long molecular dynamics (MD) simulations, we demonstrate that on binding with LDLR, there is a significant conformational change (population shift) in a distal loop (residues 211-222) region of PCSK9. Consistent with the bidirectional nature of allostery, we establish a clear correlation between the loop conformation and the binding affinity with LDLR. Using a thermodynamic argument, we establish that the loop conformations predominantly present in the apo state of PCSK9 would have lower LDLR binding affinity, and they would be potential targets for designing allosteric inhibitors. We elucidate the molecular origin of the allosteric coupling between this loop and the LDLR binding interface in terms of the population shift in a set of salt bridges and hydrogen bonds. Overall, our work provides a general strategy toward identifying allosteric hotspots: compare the conformational ensemble of the receptor between the apo and bound states of the protein and identify distal conformational changes, if any. The inhibitors should be designed to bind and stabilize the apo-specific conformations.

Over three percent of people carry a dominant pathogenic variant, yet only a fraction of carriers develop disease. Disease phenotypes from carriers of variants in the same gene range from mild to severe. Here, we investigate underlying mechanisms for this heterogeneity: variable variant effect sizes, carrier polygenic backgrounds, and modulation of carrier effect by genetic background (marginal epistasis). We leveraged exomes and clinical phenotypes from the UK Biobank and the Mt. Sinai BioMe Biobank to identify carriers of pathogenic variants affecting cardiometabolic traits. We employed recently developed methods to study these cohorts, observing strong statistical support and clinical translational potential for all three mechanisms of variable carrier penetrance and disease severity. For example, scores from our recent model of variant pathogenicity were tightly correlated with phenotype amongst clinical variant carriers, they predicted effects of variants of unknown significance, and they distinguished gain- from loss-of-function variants. We also found that polygenic scores predicted phenotypes amongst pathogenic carriers and that epistatic effects can exceed main carrier effects by an order of magnitude.

Diabetic atherosclerosis is a complex process that is characterized by diffuse and unstable lesions increasing 2-4-fold the risk of adverse cardiovascular (CV) events. Diabetic dyslipidemia has a predominant role in coronary artery disease (CAD) and has been the target of classical and emerging pharmaceutical agents with established or promising CV benefits. The aim of the present narrative review was to summarize the effects of classical and novel lipid-lowering pharmaceutical agents on lipid profile and CV outcomes in diabetic patients with established CAD or high risk of CAD. Statins remain the first-line treatment for all diabetic patients since they considerably ameliorate lipid parameters and non-lipid CV risk factors, leading to reduced CV morbidity and mortality. Complementary to statins, ezetimibe exerts lipid-lowering properties with modest but significant reductions in major adverse cardiovascular events (MACEs) and CV mortality. PCSK9 inhibitors considerably reduce LDL-C levels and lower MACEs in diabetic patients. On the other hand, fibrates may confer a very modest decline in MACE incidence, while the CV impact of omega-3 fatty acids is promising but remains questionable. Bempedoic acid and inclisiran have a potential therapeutic role in the management of diabetic dyslipidemia, but this is still not adequately documented. Given the heightened CV risk among individuals with diabetes, more decisive results would be of great importance in the utility of all these drugs.

Proprotein convertase subtilisin/kexin 9 (PCSK9) plays a crucial role in breaking down the hepatic low-density lipoprotein receptor (LDLR), thereby influencing the levels of circulating low-density lipoprotein cholesterol (LDL-C). Consequently, inhibiting PCSK9 through suitable ligands has been established as a validated therapeutic strategy for combating hypercholesterolemia and cardiovascular diseases.

Patent literature claiming novel compounds inhibiting PCSK9 disclosed from 2018 to June 2023 available in the espacenet database, which contains more than 150 million patent documents from over 100 patent-granting authorities worldwide.

The undisputable beneficial influence of PCSK9 as a pharmacological target has prompted numerous private and public institutions to patent chemical frameworks as inhibitors of PCSK9. While several compounds have advanced to clinical trials for treating hypercholesterolemia, they have not completed these trials yet. These compounds must contend in a complex market where new, costly, and advanced drugs, such as monoclonal antibodies and siRNA, are prescribed instead of inexpensive and less potent statins.

The reciprocal coordination between cholesterol absorption in the intestine and de novo cholesterol synthesis in the liver is essential for maintaining cholesterol homeostasis, yet the mechanisms governing the opposing regulation of these processes remain poorly understood. Here, we identify a hormone, Cholesin, which is capable of inhibiting cholesterol synthesis in the liver, leading to a reduction in circulating cholesterol levels. Cholesin is encoded by a gene with a previously unknown function (C7orf50 in humans; 3110082I17Rik in mice). It is secreted from the intestine in response to cholesterol absorption and binds to GPR146, an orphan G-protein-coupled receptor, exerting antagonistic downstream effects by inhibiting PKA signaling and thereby suppressing SREBP2-controlled cholesterol synthesis in the liver. Therefore, our results demonstrate that the Cholesin-GPR146 axis mediates the inhibitory effect of intestinal cholesterol absorption on hepatic cholesterol synthesis. This discovered hormone, Cholesin, holds promise as an effective agent in combating hypercholesterolemia and atherosclerosis.