Citrate Lyase Research Articles

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

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

Abstract 440: BAP1 deubiquitinates ACLY to promote lipogenesis yet predisposing cholangiocarcinoma to iron overload and ferroptosis

Abstract Background: Cholangiocarcinoma (CCA) is a highly lethal and aggressive epithelial cell malignancy of the liver and biliary tract. CCA survival remains poor and response to chemotherapy or immunotherapy is limited. We AIM to identify metabolic vulnerabilities that render CCA susceptible to ferroptosis, an iron-dependent and caspase-independent cell death driven by lipid peroxidation. Materials and Methods: We treated human and mouse CCA cell lines with ferroptosis inducers (RSL3, Erastin), inhibitors (Fer-1, Lip-1), necroptosis inhibitor and a pan-caspase inhibitor. Cell viability, intracellular and mitochondrial iron, lipid peroxidation, mitochondrial structure, and function by cell-based and biochemical assays. Gain- and loss-of-function strategies, TURBO proximity-dependent biotin identification, and metabolic techniques were used for mechanistic studies. In vivo, orthotopically implanted C57B/6 mice were treated with RSL3 or vehicle intraperitoneally, followed by assessment of tumor burden and immunophenotyping analysis. Epcam-aptamer coated nanoparticles (tMNPs) packaged with siRNA against GPX4 were used for selective ferroptosis induction. Results: We identified ferroptosis-sensitive and -resistant human and mouse CCA cells. Ferroptosis-sensitive cells, rescued by ferroptosis inhibitors but not by necroptosis or pan-caspase inhibitors, exhibited elevated intracellular free iron and mitochondrial iron overload. This led to significant mitochondrial dysfunction and structural changes associated with ferroptosis. Mitochondrial free iron triggered reactive oxygen species generation and lipid peroxidation. We identified BRCA-associated protein 1 (BAP1) as a potential driver of ferroptosis sensitivity. BAP1, mutated in 22-25% of human CCAs, is a tumor suppressor and deubiquitinase (DUB). BAP1 knockdown by siRNA protected cells from ferroptosis, while re-expression of BAP1 sensitized cells to ferroptosis. Subcellular fractionation identified BAP1 in extranuclear compartments, including mitochondria and cytosol. We found that BAP1 interacts and deubiquitinates ATP citrate lyase (ACLY), which converts iron chelator citrate to oxaloacetate and acetyl-CoA. Inhibition of mitochondrial citrate export, protected cells from iron overload and ferroptosis. In vivo, RSL3-induced ferroptosis significantly reduced tumor burden, as compared to vehicle-treated mice. RSL3-induced ferroptosis promoted an immunogenic tumor immune microenvironment. Lastly, tMNPs with siGPX4 induced marked ferroptosis of mouse CCA cells and showed maximal enrichment in liver orthotopic tumors in vivo. Conclusions: Our findings indicate that BAP1 deubiquitination of ACLY predisposes CCA cells to iron overload by exhausting citrate to support lipogenesis. CCA vulnerability to ferroptosis opens up novel therapeutic opportunities for CCA. Citation Format: Peyton Classon, Sophia Jaramillo, Danielle Carlson, Irene Yan, Tushar Patel, Sumera I. Ilyas, Rory L. Smoot, Gregory J. Gores, Davide Povero. BAP1 deubiquitinates ACLY to promote lipogenesis yet predisposing cholangiocarcinoma to iron overload and ferroptosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 440.

Abstract 1784: Glucose metabolism and de novo palmitate synthesis under normoxia and hypoxia in breast cancer cells that preferentially metastasize to lung and liver

Abstract Cancer cells are exposed to variable oxygen and nutrient availability during the metastatic process which can influence metabolic adaptations of cancer cells to metastasize to distant sites. Thus, we investigated the metabolic adaptations of breast cancer cells that preferentially metastasize to lung (metM-WntLung cells; MLg) and liver (metM-WntLiver cells; MLr) in normoxia and hypoxia and at different glucose concentrations. In normoxia, 14C-glucose uptake is similar, but mRNA abundance of hexokinase, the initial rate-limiting step in glycolysis, was 22% higher in MLg cells. This is consistent with higher 13C6-glucose flux into glycolytic metabolites pyruvate (M+3) and lactate (M+3) in MLg compared to MLr. Also, de novo palmitate synthesis from 13C6-glucose was 7.6% higher in MLg and was accompanied by higher mRNA expression of ATP-citrate lyase (ACLY), which converts citrate to acetyl-CoA for fatty acid synthesis. These suggest greater glucose metabolism in MLg compared to MLr in normoxia, consistent with reduced viability of MLr by 39% in high glucose (25 mM) concentrations. Further, mRNA abundance of CPT1A, a rate-limiting step in fatty acid oxidation, is 23% higher in MLg. Moreover, the fatty acid oxidation inhibition (etomoxir) reduced viability of MLg by 26.7% compared to MLr, suggesting that fatty acid synthesis and oxidation are critical for MLg. Protein expression of HIF1α, a transcription factor that induces glycolysis during hypoxia, is 1.5-fold higher in MLr than MLg in normoxia, consistent with higher MLr mRNA abundance of pyruvate dehydrogenase kinase (PDK1), a target of HIF1α that inhibits pyruvate dehydrogenase (PDH) activity. Surprisingly, mRNA abundance of pyruvate carboxylase (PC), the enzyme that converts pyruvate to oxaloacetate, is also higher in MLr (39%) than MLg, thus supporting a potential alternative mechanism for glucose metabolites to enter the TCA cycle in normoxia in MLr. In hypoxia, viability of MLr, relative to MLg, increased by 11% at high glucose concentration. This was accompanied by higher hexokinase (33%) and PDK1 (83%) mRNA abundance suggesting MLr’s shift towards a glycolytic phenotype. However, de novo palmitate synthesis from 13C6-glucose is higher in MLg, suggesting that palmitate synthesis is maintained in MLg even in hypoxia. Altogether, results demonstrate that glucose utilization shifts in breast cancer cells that preferentially metastasize to lung vs liver, but de novo fatty acid synthesis is higher in MLg in different oxygen conditions. Thus, targeting breast cancer cells’ adaptation to glucose and de novo fatty acid synthesis may be a potential strategy to prevent breast cancer progression to distant organs. Citation Format: Marjorie Anne A. Layosa, Morgan Conrad, Stephen Hursting, Dorothy Teegarden. Glucose metabolism and de novo palmitate synthesis under normoxia and hypoxia in breast cancer cells that preferentially metastasize to lung and liver [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1784.

Disease-associated astrocyte epigenetic memory promotes CNS pathology.

Disease-associated astrocyte subsets contribute to the pathology of neurologic diseases, including multiple sclerosis and experimental autoimmune encephalomyelitis1-8 (EAE), an experimental model for multiple sclerosis. However, little is known about the stability of these astrocyte subsets and their ability to integrate past stimulation events. Here we report the identification of an epigenetically controlled memory astrocyte subset that exhibits exacerbated pro-inflammatory responses upon rechallenge. Specifically, using a combination of single-cell RNA sequencing, assay for transposase-accessible chromatin with sequencing, chromatin immunoprecipitation with sequencing, focused interrogation of cells by nucleic acid detection and sequencing, and cell-specific in vivo CRISPR-Cas9-based genetic perturbation studies we established that astrocyte memory is controlled by the metabolic enzyme ATP-citrate lyase (ACLY), which produces acetyl coenzyme A (acetyl-CoA) that is used by histone acetyltransferase p300 to control chromatin accessibility. The number of ACLY+p300+ memory astrocytes is increased in acute and chronic EAE models, and their genetic inactivation ameliorated EAE. We also detected the pro-inflammatory memory phenotype in human astrocytes in vitro; single-cell RNA sequencing and immunohistochemistry studies detected increased numbers of ACLY+p300+ astrocytes in chronic multiple sclerosis lesions. In summary, these studies define an epigenetically controlled memory astrocyte subset that promotes CNS pathology in EAE and, potentially, multiple sclerosis. These findings may guide novel therapeutic approaches for multiple sclerosis and other neurologic diseases.

Enhanced lipid biosynthesis in oral squamous cell carcinoma cancer-associated fibroblasts contributes to tumor progression: Role of IL8/AKT/p-ACLY axis.

Lipid metabolic reprogramming of tumor cells has been proven to play a critical role in tumor initiation and development. However, lipid metabolism in cancer-associated fibroblasts (CAFs) has rarely been studied, particularly in CAFs of oral squamous cell carcinoma (OSCC). Additionally, the molecular mechanism by which tumor cells regulate lipid metabolism in fibroblasts is unclear. In this study, we found that phosphorylated ATP citrate lyase (p-ACLY), a key lipid metabolic enzyme, was upregulated in OSCC CAFs. Compared to paracancerous normal fibroblasts, CAFs showed enhanced lipid synthesis, such as elevated cytosolic acetyl-CoA level and accumulation of lipid droplets. Conversely, reduction of p-ACLY level blocked this biological process. In addition, blocking lipid synthesis in CAFs or inhibiting fatty acid uptake by OSCC cells reduced the promotive effects of CAFs on OSCC cell proliferation, invasion, and migration. These findings suggested that CAFs are one of lipid sources required for OSCC progression. Mechanistically, AKT signaling activation was involved in the upregulation of p-ACLY level and lipid synthesis in CAFs. Interleukin-8 (IL8), an exocrine cytokine of OSCC cells, could activate AKT and then phosphorylate ACLY in fibroblasts. This study suggested that the IL8/AKT/p-ACLY axis could be considered as a potential target for OSCC treatment.

ATP citrate lyase (ACLY)-dependent immunometabolism in mucosal T cells drives experimental colitis in vivo

ObjectiveMucosal T cells play a major role in inflammatory bowel disease (IBD). However, their immunometabolism during intestinal inflammation is poorly understood. Due to its impact on cellular metabolism and proinflammatory...

Beyond Statins: Novel Lipid-Lowering Agents for Reducing Risk of Atherosclerotic Cardiovascular Disease

Although statins have served as the cornerstone for pharmacological lowering of lipid levels in atherosclerotic cardiovascular disease (ASCVD) risk reduction, many patients are unable to achieve target doses of statin medication due to side effects or target levels of cholesterol reduction on statin monotherapy. The landscape of lipid-lowering strategies has expanded in recent years, with the emergence of therapies that make use of small interfering RNA (siRNA) and antisense oligonucleotides, in addition to traditional small-molecule agents. Non-statin therapies that have shown promising results in randomized controlled trials include adenosine triphosphate-citrate lyase inhibitors, proprotein convertase subtilisin/kexin 9 (PCSK9)-inhibiting antibodies and siRNA, omega-3 polyunsaturated fatty acids, and lipoprotein(a) gene-inhibiting siRNA and ASOs, in addition to older therapies such as ezetimibe. In contrast, cholesteryl ester transfer protein (CETP) inhibitors have shown less promising results in randomized trials. The purpose of this narrative review is to summarize the evidence for these medications, with a focus on phase III randomized trials.

Fed-batch fermentation of Mucor circinelloides reveals significant improvement in biomass and lipid accumulation through performance evaluation, chemical analysis, and expression profiling

This study aimed to improve the lipid and biomass yields of Mucor circinelloides WJ11 by implementing four different fed-batch fermentation strategies, varied in time and glucose concentration (S1-S4). The S1 fermentation strategy yielded the highest biomass, lipid, and fatty acid content (22 ± 0.7 g/L, 53 ± 1.2 %, and 28 ± 1.6 %) after 120 and 144 h, respectively. The γ-linolenic acid titer of 0.75 ± 0.0 g/L was greatest in S3 after 48 h. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to analyze the transcription of key genes involved in lipid accumulation. The glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and ATP-citrate lyase genes showed increased expression levels. Fourier-transform infrared (FTIR) spectroscopy was used to analyze the biochemical profile during fermentation strategies. Optimal abiotic factors for production efficiency included pH 6.5, 25–26 °C, 15 % (v/v) inoculum, 500 rpm, 20 %-30 % dissolved oxygen, and 120 h fermentation. Glucose co-feeding offers valuable insights to develop effective fermentation strategies for lipid production.

Effects of bempedoic acid on markers of inflammation and Lp(a).

To study the effect of bempedoic acid on markers of inflammation and lipoprotein (a) to help determine if the drug would be useful to treat patients with elevated cardiovascular risks and residual cardiovascular risk despite optimal low-density lipoprotein cholesterol (LDL-C) levels. Bempedoic acid is found to cause significant reduction in LDL-C and high-sensitivity C-reactive protein (hs-CRP) in various randomized clinical trials. Multiple meta-analyses have also found that bempedoic acid therapy leads to reduction in non-high-density lipoprotein cholesterol (non-HDL-C), total cholesterol (TC) and apolipoprotein B (ApoB) levels. However, it has minimal effect on lipoprotein (a) (Lp(a)) level. Bempedoic acid is a new lipid-lowering agent that inhibits enzyme ATP-citrate lyase in the cholesterol biosynthesis pathway. Major risk of cardiovascular events and its associated morbidity and mortality are proportional to LDL-C and inflammatory markers levels. It was found that bempedoic acid significantly lowers LDL-C, hs-CRP and other inflammatory markers levels. This drug could potentially be used in patients with elevated cardiovascular risk, in patients with residual cardiovascular risk despite attaining LDL-C goal and in statin intolerant patients.

SIRT2-mediated deacetylation of ACLY promotes the progression of oesophageal squamous cell carcinoma.

ATP citrate lyase (ACLY), as a key enzyme in lipid metabolism, plays an important role in energy metabolism and lipid biosynthesis of a variety of tumours. Many studies have shown that ACLY is highly expressed in various tumours, and its pharmacological or gene inhibition significantly inhibits tumour growth and progression. However, the roles of ACLY in oesophageal squamous cell carcinoma (ESCC) remain unclear. Here, our data showed that ACLY inhibitor significantly attenuated cell proliferation, migration, invasion and lipid synthesis in different ESCC cell lines, whereas the proliferation, migration, invasion and lipid synthesis of ESCC cells were enhanced after ACLY overexpression. Furthermore, ACLY inhibitor dramatically suppressed tumour growth and lipid metabolism in ESCC cells xenografted tumour model, whereas ACLY overexpression displayed the opposite effect. Mechanistically, ACLY protein harboured acetylated modification and interacted with SIRT2 protein in ESCC cells. The SIRT2 inhibitor AGK2 significantly increased the acetylation level of ACLY protein and inhibited the proliferation and migration of ESCC cells, while overexpression of ACLY partially reversed the inhibitory effect of AGK2 on ESCC cells. Overall, these results suggest that targeting the SIRT2/ACLY signalling axis may be a potential therapeutic strategy for ESCC patients.

Role of ACLY in the development of gastric cancer under hyperglycemic conditions

AbstractTo investigate the impact of hyperglycemia on the prognosis of patients with gastric cancer and identify key molecules associated with high glucose levels in gastric cancer development, RNA sequencing data and clinical features of gastric cancer patients were obtained from The Cancer Genome Atlas (TCGA) database. High glucose‐related genes strongly associated with gastric cancer were identified using weighted gene co‐expression network and differential analyses. A gastric cancer prognosis signature was constructed based on these genes and patients were categorized into high‐ and low‐risk groups. The immune statuses of the two patient groups were compared. ATP citrate lyase (ACLY), a gene significantly related to the prognosis, was found to be upregulated upon high‐glucose stimulation. Immunohistochemistry and molecular analyses confirmed high ACLY expression in gastric cancer tissues and cells. Gene Set Enrichment Analysis (GSEA) revealed the involvement of ACLY in cell cycle and DNA replication processes. Inhibition of ACLY affected the proliferation and migration of gastric cancer cells induced by high glucose levels. These findings suggest that ACLY, as a high glucose‐related gene, plays a critical role in gastric cancer progression.

Stability Indicating Method Development and Validation for the Estimation of Bempedoic Acid by RP-HPLC.

Bempedoic acid (BEM) belongs to a category of drugs known as Adenosine triphosphate-citrate Lyase (ACL) inhibitors. It is a prodrug with intracellular activation that is administered orally. Bempedoic acid is used to treat existing atherosclerotic cardiovascular diseases, mainly hypercholesterolemia. For the stability-indicating assay, the HPLC method was employed using a Kromasil 100-5-C8 column (100 mm × 4.6 mm), a UV detector set at 230 nm, and a mobile phase comprising a 70:30 v/v mixture of acetonitrile and 0.1% Orthophosphoric Acid (OPA) buffer. The method was operated at an ambient temperature with a flow rate of 1 mL/min. The method developed has been statistically validated according to ICH guidelines. The stability-indicating method was executed using a Kromasil 100-5-C8 (100 mm × 4.6 mm) column at a 1.0 mL/min flow rate. A mixture of acetonitrile and 0.1% Orthophosphoric Acid (OPA) buffer in a 70:30 v/v ratio made up the mobile phase. BEM's retention times were discovered to be 1.88 minutes each. The temperature was kept at room temperature. 234 nm was the ideal wavelength for BEM. According to ICH criteria, the approach developed has undergone statistical validation. BEM's % RSD was discovered to be 0.6, respectively. For BEM, the % recovery was determined to be 100.0%. Regression models for bempedoic acid yielded LoD and LoQ values of 3.3 and 10.1 g/mL, respectively. The method showed good reproducibility and recovery with a % RSD less than 2. Studies on forced degradation confirmed the method's capacity to indicate stability in the presence of stress conditions, such as acid, basic, peroxide, UV, heat, and humidity. Both the retention times and the run time were shortened. In accordance with ICH Q2 (R1) guidelines, this method was successfully tested with HPLC to confirm the chemical structures of newly produced degradation products of bempedoic acid.

Cancer-associated fibroblast-derived acetate promotes pancreatic cancer development by altering polyamine metabolism via the ACSS2–SP1–SAT1 axis

The ability of tumour cells to thrive in harsh microenvironments depends on the utilization of nutrients available in the milieu. Here we show that pancreatic cancer-associated fibroblasts (CAFs) regulate tumour cell metabolism through the secretion of acetate, which can be blocked by silencing ATP citrate lyase (ACLY) in CAFs. We further show that acetyl-CoA synthetase short-chain family member 2 (ACSS2) channels the exogenous acetate to regulate the dynamic cancer epigenome and transcriptome, thereby facilitating cancer cell survival in an acidic microenvironment. Comparative H3K27ac ChIP–seq and RNA–seq analyses revealed alterations in polyamine homeostasis through regulation of SAT1 gene expression and enrichment of the SP1-responsive signature. We identified acetate/ACSS2-mediated acetylation of SP1 at the lysine 19 residue that increased SP1 protein stability and transcriptional activity. Genetic or pharmacologic inhibition of the ACSS2–SP1–SAT1 axis diminished the tumour burden in mouse models. These results reveal that the metabolic flexibility imparted by the stroma-derived acetate enabled cancer cell survival under acidosis via the ACSS2–SP1–SAT1 axis.

Abstract 2048 Loss of ATP-dependent Citrate Lyase Abrogates Phosphatidate Phosphatase Activity in the oleaginous yeast Yarrowia lipolytica

Abstract 2048 Loss of ATP-dependent Citrate Lyase Abrogates Phosphatidate Phosphatase Activity in the oleaginous yeast Yarrowia lipolytica

Vitamin-C-dependent downregulation of the citrate metabolism pathway potentiates pancreatic ductal adenocarcinoma growth arrest.

In pancreatic ductal adenocarcinoma (PDAC), metabolic rewiring and resistance to standard therapy are closely associated. PDAC cells show enormous requirements for glucose-derived citrate, the first rate-limiting metabolite in the synthesis of new lipids. Both the expression and activity of citrate synthase (CS) are extraordinarily upregulated in PDAC. However, no previous relationship between gemcitabine response and citrate metabolism has been documented in pancreatic cancer. Here, we report for the first time that pharmacological doses of vitamin C are capable of exerting an inhibitory action on the activity of CS, reducing glucose-derived citrate levels. Moreover, ascorbate targets citrate metabolism towards the de novo lipogenesis pathway, impairing fatty acid synthase (FASN) and ATP citrate lyase (ACLY) expression. Lowered citrate availability was found to be directly associated with diminished proliferation and, remarkably, enhanced gemcitabine response. Moreover, the deregulated citrate-derived lipogenic pathway correlated with a remarkable decrease in extracellular pH through inhibition of lactate dehydrogenase (LDH) and overall reduced glycolytic metabolism. Modulation of citric acid metabolism in highly chemoresistant pancreatic adenocarcinoma, through molecules such as vitamin C, could be considered as a future clinical option to improve patient response to standard chemotherapy regimens.

Lipid metabolism-related long noncoding RNA RP11-817I4.1 promotes fatty acid synthesis and tumor progression in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common types of tumors. The influence of lipid metabolism disruption on the development of HCC has been demonstrated in published studies. To establish an HCC prognostic model for lipid metabolism-related long non-coding RNAs (LMR-lncRNAs) and conduct in-depth research on the specific role of novel LMR-lncRNAs in HCC. Correlation and differential expression analyses of The Cancer Genome Atlas data were used to identify differentially expressed LMR-lncRNAs. Quantitative real-time polymerase chain reaction analysis was used to evaluate the expression of LMR-lncRNAs. Nile red staining was employed to observe intracellular lipid levels. The interaction between RP11-817I4.1, miR-3120-3p, and ATP citrate lyase (ACLY) was validated through the performance of dual-luciferase reporter gene and RIP assays. Three LMR-lncRNAs (negative regulator of antiviral response, RNA transmembrane and coiled-coil domain family 1 antisense RNA 1, and RP11-817I4.1) were identified as predictive markers for HCC patients and were utilized in the construction of risk models. Additionally, proliferation, migration, and invasion were reduced by RP11-817I4.1 knockdown. An increase in lipid levels in HCC cells was significantly induced by RP11-817I4.1 through the miR-3120-3p/ACLY axis. LMR-lncRNAs have the capacity to predict the clinical characteristics and prognoses of HCC patients, and the discovery of a novel LMR-lncRNAs, RP11-817I4.1, revealed its role in promoting lipid accumulation, thereby accelerating the onset and progression of HCC.

Early starvation in European seabass (Dicentrarchus labrax) larvae has no drastic effect on hepatic intermediary metabolism in juveniles.

The present study aims to investigate nutritional programming through early starvation in the European seabass (Dicentrarchus labrax). European seabass larvae were fasted at three different developmental periods for three durations from 60 to 65 dph (F1), 81 to 87 dph (F2), and 123 to 133 dph (F3). Immediate effects were investigated by studying gene expression of npy (neuropeptide Y) and avt (Arginine vasotocin) in the head, while potential long-term effects (i.e., programming) were evaluated on intermediary metabolism later in life (in juveniles). Our findings indicate a direct effect regarding gene expression in the head only for F1, with higher avt mRNA level in fasted larved compared to controls. The early starvation periods had no long-term effect on growth performance (body weight and body length). Regarding intermediary metabolism, we analyzed related key plasma metabolites which reflect the intermediary metabolism: no differences for glucose, triglycerides, and free fatty acids in the plasma were observed in juveniles irrespective of the three early starvation stimuli. As programming is mainly linked to molecular mechanisms, we then studied hepatic mRNA levels for 23 key actors of glucose, lipid, amino acid, and energy metabolism. For many of the metabolic genes, there was no impact of early starvation in juveniles, except for three genes involved in glucose metabolism (glut2-glucose transporter and pk-pyruvate kinase) and lipid metabolism (acly-ATP citrate lyase) which were higher in F2 compared to control. Together, these results highlight that starvation between 81 to 87 dph may have more long-term impact, suggesting the existence of a developmental window for programming by starvation. In conclusion, European seabass appeared to be resilient to early starvation during larvae stages without drastic impacts on intermediary metabolism later in life.

Simultaneous determination of BGT-002 and its acyl glucuronide metabolite ZM326E-M2 in human plasma by liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study

BGT-002, a new type of ATP-citrate lyase inhibitor, is a promising therapeutic for treatment of hypercholesterolemia. After an oral administration of BGT-002 to subjects, it underwent extensive metabolism and an acyl monoglucuronide (ZM326E-M2) on 1- carboxylic acid group was the major circulating metabolite. In this study, an LC-MS/MS method was developed and validated for the simultaneous determination of BGT-002 and ZM326E-M2 in plasma and the evaluation of their pharmacokinetic characteristics in humans. After extraction from the plasma by acetonitrile-induced protein precipitation, the analytes were separated on a Waters ACQUITY UPLC® BEH C18 column using acetonitrile and 2 mM ammonium acetate containing 0.1% formic acid as the mobile phase for gradient elution. Negative electrospray ionization was performed using multiple reaction monitoring (MRM) of m/z 501.3→325.4 for ZM326E-M2 and m/z 507.3→331.2 for D6-ZM326E-M2, and pseudo-MRM of m/z 325.3→325.3 for BGT-002 and m/z 331.3→331.3 for D6-ZM326E, respectively. The method was validated with respect to accuracy, precision, linearity, stability, selectivity, matrix effect, and recovery. The analytical range in human plasma was linear over a concentration range of 0.0500–50.0 μg/mL for BGT-002 and 0.0100–10.0 μg/mL for ZM326E-M2. The pharmacokinetic results showed that after a single oral administration of 100 mg BGT-002, the parent drug was rapidly absorbed with a mean time to peak concentration (tmax) of 1.13 h, compared with BGT-002, the tmax (4.00 h) of ZM326E-M2 was significantly delayed. The peak concentration and plasma exposure of ZM326E-M2 were about 14.1% and 19.5% of the parent drug, suggesting that attention should be paid to the safety and efficacy of ZM326E-M2 in clinical research.

Low-Density Lipoprotein Cholesterol-Lowering Drugs: A Narrative Review.

The modern history of cholesterol-lowering drugs started in 1972 when Dr. Akira Endo identified an active compound (compactin) that inhibited cholesterol biosynthesis from the culture broth of blue-green mold (Penicillium citrinum Pen-51). Since 1987, statins have represented the milestone for the treatment of atherosclerotic cardiovascular disease. A new therapy for the treatment of hypercholesterolemia since the discovery of statins is ezetimibe, the first and only agent inhibiting intestinal cholesterol absorption. Ezetimibe was approved by the FDA in October 2002. A year later, the association between gain-of-function PCSK9 genetic mutations and hypercholesterolemia was reported, and this discovery opened a new era in lipid-lowering therapies. Monoclonal antibodies and small-interfering RNA approaches to reduce PCSK9 were developed and approved for clinical use in 2015 and 2022, respectively. Finally, the newly approved bempedoic acid, an oral adenosine triphosphate citrate lyase inhibitor that lowers LDL-C, is able to reduce major adverse cardiovascular events in both primary and secondary prevention. In the present narrative review, we summarize the pharmacological properties and the clinical efficacy of all these agents currently used for a tailored therapy of hypercholesterolemia in patients with atherosclerotic cardiovascular disease.

Impact of Bempedoic Acid on Total Cardiovascular Events

The ATP citrate lyase (ACL) inhibitor, bempedoic acid, reduces low-density lipoprotein cholesterol (LDL-C) level and major adverse cardiovascular events (MACE) by 13% in patients at high cardiovascular risk with intolerance of statin and high-intensity statin medications. The effects of bempedoic acid on total cardiovascular events remain unknown. To determine the impact of bempedoic acid on the total incidence of MACE. Included in this prespecified analysis of the Cholesterol Lowering via Bempedoic Acid, an ACL-Inhibiting Regimen (CLEAR) Outcomes trial were patients with, or at high risk for, cardiovascular disease, with hypercholesterolemia and inability to take guideline-recommended statins. Study data were analyzed from December 2016 to November 2022. Patients were randomly assigned to treatment with bempedoic acid or placebo daily. The primary end point was the time to first event for a composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or coronary revascularization (MACE-4). The key secondary end point was time to first event for cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke (MACE-3). This prespecified analysis compared the total number of cardiovascular events in the treatment groups. A total of 13 970 patients (mean [SD] age, 65 [9] years; 7230 male [51.8%]) were included in the study. A total of 9764 participants (69.9%) had prior atherosclerotic cardiovascular disease and a baseline LDL-C level of 139 mg/dL; treatment with bempedoic acid resulted in a 21% reduction in LDL-C level and a 22% reduction in high-sensitivity C-reactive protein (hsCRP) level at 6 months. Median (IQR) follow-up was 3.4 (3.1-3.9) years. A total of 1746 positively adjudicated first MACE-4 events and 915 additional MACE events in 612 patients were recorded, with coronary revascularization representing 32.8% (573 of 1746) of first events and 69.4% (635 of 915) of additional events. For the total incidence of cardiovascular events, treatment with bempedoic acid was associated with a reduction in risk of MACE-4 (hazard ratio [HR], 0.80; 95% CI, 0.72-0.89; P <.001), MACE-3 (HR, 0.83; 95% CI, 0.73-0.93; P = .002), myocardial infarction (HR, 0.69; 95% CI, 0.58-0.83; P < .001), and coronary revascularization (HR, 0.78; 95% CI, 0.68-0.89; P <.001), although no statistically significant difference was observed for stroke (HR, 0.80; 95% CI, 0.63-1.03). A lower HR for protection with bempedoic acid was observed with increasing number of MACE events experienced by patients. Lowering LDL-C level with bempedoic acid reduced the total number of cardiovascular events in patients with high cardiovascular risk, statin therapy intolerance, and elevated LDL-C levels.