👤 William Sean Davidson

Apolipoprotein AV (APOA5) regulates intravascular triglyceride metabolism by binding to the angiopoietin-like protein 3/8 complex (ANGPTL3/8) and suppressing its ability to unfold the native conformation of lipoprotein lipase (LPL). LPL unfolding results in loss of catalytic activity and the detachment of LPL from the surface of cells. An Show less

Apolipoprotein B (APOB) containing lipoproteins contribute to atherosclerosis by entering the arterial wall through the endothelial cell (EC) surface receptors scavenger receptor-BI (SR-BI) and activin receptor-like kinase 1 (ALK1). We used N-terminal fragments of APOB, molecular modeling, and site-directed mutagenesis to identify and block the binding of chylomicrons and LDL to these receptors in cells and mice. We discovered that different APOB regions interact with SR-BI and ALK1 expressed on ECs APOB48 lipoproteins were only internalized by SR-BI. A fragment of APOB, comprising 18% of the N-terminal sequence, APOB18, reduced the uptake and transport of both chylomicrons and LDL by ECs, whereas a shorter fragment, APOB12, only blocked ALK1 mediated uptake of APOB100 containing lipoproteins. Importantly, overexpressing APOB18 decreased atherosclerosis in hypercholesterolemic mice. These findings identify the N-terminal region of APOB as the cause of atherosclerosis and illustrate an approach to treating or preventing vascular disease. Show less

Most patients with heterozygous familial hypercholesterolemia fail to achieve adequate low-density lipoprotein (LDL) cholesterol lowering. Here we carried out a randomized trial to test the safety and efficacy of obicetrapib, a highly selective cholesteryl ester transfer protein inhibitor that lowers LDL cholesterol levels in patients with heterozygous familial hypercholesterolemia and an LDL cholesterol level ≥70 mg dl Show less

Low-density lipoprotein cholesterol (LDL-C) levels <100 mg/dL are generally considered normal. We tested the controversial hypothesis that a subset of individuals with 'normal' LDL-C levels may have a non-negligible risk of coronary artery disease (CAD) due to inherited factors, including monogenic variants and polygenic risk scores (PGS). A retrospective analysis of a prospective cohort from the Genomic Health Initiative at Endeavor Health, including 7880 participants without a prior diagnosis of CAD and not on statins at recruitment. Participants were stratified by baseline LDL-C levels and followed for incident CAD. The association of CAD risk with carrier status for pathogenic/likely pathogenic (P/LP) variants in Among participants, 31.2 % had LDL-C <100 mg/dL (normal), 39.5 % had LDL-C 100-129 mg/dL, and 29.3 % had LDL-C ≥130 mg/dL. Over a median follow-up of 8 years, CAD was diagnosed in 5.3 %, 6.9 %, and 7.6 % of participants in these LDL-C groups, respectively. Among those with normal LDL-C, CAD incidence rose to 9.5 % in individuals with high genetic risk (P/LP variants and/or high PGS). Genetic risk was significantly associated with CAD in multivariable models ( Individuals with 'normal' LDL-C levels can have substantial CAD risk if they carry high genetic risk. These findings underscore the importance of incorporating genetic information into CAD risk assessment, even among those with traditionally normal lipid profiles. Show less

Dyslipidemia is common in patients with MASLD, but the frequency and significance of inherited disorders of dyslipidemia are unclear. We investigated the prevalence and significance of pathogenic variants associated with selected monogenic disorders of dyslipidemia in 3358 patients with well-characterised MASLD. We identified clinically relevant variants in APOB, MTTP, PCSK9, ANGPTL3, LDLR and LDLRAP1 genes which can cause hypobetalipoproteinemia (HBL) and familial hypercholesterolemia (FH). Using ClinVar annotations as initial variant selection, we identified 2027 variants in those 6 genes which are reported as 'pathogenic' or 'likely pathogenic' (P/LP). We first assessed for the presence of P/LP variants in the study cohort and then investigated the effect of carrying P/LP variants on liver histology, by comparing ~4 matched controls for each APOB and LDLR carrier. As interpretative analyses, we also looked at the difference between liver enzymes, lipid measures and outcomes between the carriers and matched controls. Twenty-two variants among these 2027 P/LP variants were present in 24 out of 3358 patients (12 ApoB, 10 LDLR, 1 ANGPTL3 and 1 MTTP variant carriers). Compared to controls, APOB carriers had higher steatosis grade (2.4 vs. 1.7, p-value 0.0028), higher NAFLD activity score (NAS) (4.9 vs. 3.8, p-value 0.04), and numerically higher but statistically not significant fibrosis stage (1.2 vs. 1.1, p-value 0.75) and ALT (87.4 vs. 58.1 U/L, p-value 0.06). Their LDL-c (51 vs. 147.8 mg/dL, p-value 6.1E-09) and triglycerides (91.5 vs. 160.6 mg/dL, p-value 2.8E-03) were significantly lower. Compared to controls, LDLR carriers had numerically higher steatosis grade, NAS, fibrosis stage and LDL-c levels, but these were not statistically different. Monogenic disorders of dyslipidemia are rarely present in patients with MASLD and are sometimes associated with worse liver histology. Testing for these conditions may be considered on a case-by-case basis. Show less

Branched-chain α-amino acids (BCAAs) support protein synthesis and their oxidation is restrained by branched-chain α-keto acid dehydrogenase kinase (BCKDK). We previously observed that in the brains of Bckdk knockout (KO) mice, BCAAs fall while glutamate is preserved and other amino acids rise. We asked why this profile emerges and how it affects skeletal muscle versus brain during nutrient stress. Motor behavior, protein synthesis and nutrient signaling were compared in the skeletal muscle and brains of wildtype (WT) and Bckdk KO male mice. In addition, nitrogen delivery into brain from BCAAs was assessed using stable isotope tracing and mass spectrometry imaging. Bckdk KO showed normal grip strength but poor beam traversal and reduced wheel running during protein restriction. In skeletal muscle, leucine or protein-feeding stimulated and fasting suppressed mechanistic target of rapamycin complex 1 (mTORC1) signaling in both genotypes. Fasting reduced muscle protein synthesis in both strains without activating the integrated-stress response (ISR). In contrast, Bckdk KO brains exhibited ISR activation during fasting, and up-regulation of Atf4 and its target genes, including Slc7a5 mRNA. Tracer studies revealed lower serum [ Show less

We recently showed that patients with atherosclerotic cardiovascular disease (ASCVD) carry a substantial but largely unrecognized burden of early Alzheimer's disease (AD) pathology. In the BROADWAY pivotal phase 3 lipid-lowering trial, nearly half of participants with high-risk ASCVD had plasma p-tau217 concentrations above thresholds associated with preclinical AD, yet none had undergone evaluation for cognitive impairment. In this population, apolipoprotein E ε4 (APOE4) carriers were disproportionately represented among those with the highest p-tau217 levels. These findings expose a critical gap between cardiovascular care and dementia prevention and raise the question whether interventions targeting shared pathophysiology could address both conditions simultaneously. Cholesteryl ester transfer protein (CETP) inhibition has emerged as a candidate for this dual role. In BROADWAY, obicetrapib reduced p-tau217 progression across the study population, with effects most pronounced in APOE4 carriers. In fact, treatment differences favoring obicetrapib were observed across all measured AD biomarkers in high-risk subgroups, including neurofilament light chain, glial fibrillary acidic protein, and the amyloid-beta (Aβ) 42:40 ratio. Unlike approaches that target downstream pathology, such as amyloid plaques already deposited in the brain or the inflammatory consequences of established disease, CETP inhibition may address the upstream processes involved in initiating the pathological cascade: lipid dysregulation, cholesterol ester accumulation in glial cells, impaired cholesterol efflux, lipid peroxidation, oxysterol formation, and deficient antioxidant transport. This review examines the biological rationale linking APOE4 status to disordered lipid metabolism in both peripheral and central compartments, the genetic and epidemiological evidence supporting CETP as a therapeutic target, the mechanisms through which CETP inhibition might confer neuroprotection, and the clinical data suggesting obicetrapib as the first oral agent associated with favorable changes in AD biomarkers across both amyloid and tau axes in individuals at high genetic risk for the development of AD. Show less

Prior to a cardiovascular outcomes trial (CVOT), novel cholesterol-lowering therapies undergo phase 2/3 studies for their lipid and atherosclerotic effects and safety (non-CVOTs). Since the occurrence of major adverse cardiovascular events (MACE) is part of the safety assessment, nominal reductions or increases may be observed prior to definitive testing of the effect in a CVOT. To investigate if the observed MACE treatment effect in non-CVOT lipid-lowering registration studies holds value in predicting the outcome in a CVOT trial, typically reported later than the initial lipid-lowering studies. We reviewed recent development programs for cholesterol-lowering drugs that had completed non-CVOT and CVOT studies. MACE data were compared for phase 2/3 non-CVOT versus pivotal CVOT results. Our primary outcome was a qualitative comparison for directionally concordant consistency in MACE risk ratio treatment effects (harm, neutrality, or benefit). Correlation analysis was also performed. Seven drugs were reviewed in 3 cholesterol-lowering classes: CETP inhibitors, bempedoic acid, and PCSK9 inhibitors. Concordance in non-CVOT vs CVOT results was seen in 6 of 7 drugs. One drug (dalcetrapib) had a trend for benefit observed, albeit with very small numbers, in early development, but showed a neutral CVOT. There was a moderate correlation between the risk reductions or increases from the non-CVOTs and CVOTs: Within the limitations of the drugs studied and the variability in MACE definitions, there is value in the results of non-CVOTs to predict the CVOT outcome. Show less

Cholesteryl ester transfer protein (CETP) inhibition reduces low density lipoprotein-cholesterol (LDL-C) while simultaneously increasing high density lipoprotein-cholesterol (HDL-C) levels and improving HDL-particle functionality. These lipoprotein modifications may provide a novel pathway for Alzheimer disease (AD) prevention through effects on lipid modulation, antioxidant activity, and neuro-inflammation. This approach could prove particularly beneficial for APOE4 carriers, who face elevated risks for both AD and atherosclerotic cardiovascular disease (ASCVD). To examine the effects of obicetrapib, an oral CETP inhibitor, on biomarker changes indicative of AD pathology among patients with ASCVD DESIGN: This was a pre-specified substudy of the BROADWAY trial, a phase 3, double-blind, placebo-controlled pivotal registration trial to evaluate the LDL-C lowering efficacy of obicetrapib in adult patients with established ASCVD and/or heterozygous familial hypercholesterolemia (HeFH), whose LDL-C was not adequately controlled, despite being on maximally tolerated lipid-lowering therapy. The trial was conducted across 188 sites in China, Europe, Japan, and the United States. Participants were recruited from cardiology clinics and lipid specialty centers from 2021 to 2024. Participants with ASCVD in BROADWAY who had known ApoE status and phosphorylated tau-217 (p-tau217) measured at baseline and 12 months. Participants in BROADWAY were randomized 2:1 to receive oral obicetrapib 10 mg daily or placebo for 12 months. AD plasma biomarkers were measured at baseline and 12 months using standardized SIMOA assays. The key outcome measure of interest was change in plasma p-tau217 from baseline to 12 months. Other outcome measures included changes in p-tau217/(Aβ42:40), p-tau181, glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL). The analysis population consisted of 1535 (61 %) of the 2530 BROADWAY participants. Median age was 67 years and 67.0 % were male. Baseline p-tau217 levels varied significantly by ApoE subgroups, with ApoE4 carriers generally having higher concentrations and ApoE4/E4 participants exhibiting the highest median concentration (0.56 pg/mL). Obicetrapib significantly attenuated p-tau217 increases compared to placebo (adjusted mean 2.09 % vs 4.94 %; P = 0.025). Treatment differences were most pronounced in ApoE4 carriers, where adjusted mean increases were 1.92 % and 6.91 %, for obicetrapib and placebo, respectively (P = 0.041). Furthermore, among ApoE4/E4 participants, there was a 7.81 % adjusted mean decrease in p-tau217 with obicetrapib compared to a 12.67 % increase with placebo, representing a 20.48 % treatment difference (P = 0.010). Positive trends were observed across secondary biomarkers, with obicetrapib also significantly limiting increases in the p-tau217/Aβ42:40 ratio compared to placebo (2.51 % vs 6.55 %; P = 0.004). In addition, among ApoE4/E4 participants, obicetrapib demonstrated significant effects on GFAP (-6.39 % vs +8.85 %; P = 0.006) and NfL (-10.49 % vs +6.82 %; P = 0.020). Strong correlations were observed between end-of-study obicetrapib plasma concentrations and biomarker improvements (r=-0.64), suggesting CETP inhibition as a potential mechanism, although other drug effects may also contribute to these changes. Obicetrapib significantly slowed AD biomarker progression over 12 months in participants with ASCVD, with the greatest effects in ApoE4 carriers. Among ApoE4/E4 participants, obicetrapib reduced p-tau217 levels by a placebo-adjusted 20.48 % and demonstrated consistent effects across multiple AD biomarkers. These findings represent the first demonstration of an oral intervention capable of reducing both beta-amyloid and tau pathology biomarkers in ApoE4 carriers, offering a potential preventive strategy for this high-risk population who currently have no effective prevention options. Future research will need to establish whether these biomarker changes translate to clinical benefits in dedicated AD prevention trials. ClinicalTrials.gov Identifier: NCT05142722. Show less

Current genetic testing for coronary artery disease (CAD) primarily targets monogenic variants in individuals with severe hypercholesterolemia. Whether supplementing monogenic testing with polygenic risk scores for CAD and Lp(a; lipoprotein[a]) levels [PRS A genetic probability for CAD (GenProb In the UK Biobank development cohort, PVs, polygenic risk scores for CAD and PRS GenProb Show less

Short sleep duration, low physical activity (PA), and sedentary behavior (SB) are associated with negative health outcomes and highly prevalent in adolescents. This study examined changes in the amount and timing of PA and SB following a 1-week sleep extension manipulation in adolescents. Forty-three habitually short-sleeping (≤7 h/night on school days), habitually inactive (<3 hours of regular physical activity per week), and healthy-weight adolescents (16.0 ± 1.24 years, 69.8% female; 86% White) completed a randomized crossover procedure during the school year. Participants slept for 1 week on their typical school schedule (Typical Sleep, TS), and 1 week during which time in bed was extended by ≥1 hour each school night (Sleep Extension, EXT). Home-monitoring of sleep with wrist-worn actigraphy and activity with thigh-worn accelerometer was completed during both conditions. Relationships between sleep, SB, PA, and experimental manipulation were assessed with linear mixed models. SB and light PA (LPA) across the 24 days decreased significantly during EXT compared to TS by 72 minutes and 13.2 minutes, respectively (95% CI: -102, -42, p < .001; 95% CI: -26.4, 0.00, p = .048). SB decreased predominantly between the hours of 18:00-00:00 (-39 minute 95% CI: -54.6, -24, p < .001). There was no significant change in moderate-to-vigorous PA (MVPA) between conditions (p > .05). Increased sleep duration replaced time spent in SB primarily in the evening hours. While LPA decreased primarily in the morning hours, the amount of change was small and likely not clinically significant. Sleep extension did not impact MVPA. Show less

Atherosclerotic CVD is a major cause of death in individuals with type 1 diabetes mellitus (T1DM). However, conventional risk factors do not fully account for the increased risk. This study aimed to investigate whether serum proteins associate with diabetes status and the occurrence of CVD in T1DM. We used isotope dilution-MS/MS to quantify 28 serum proteins in 228 subjects participating in the prospective Coronary Artery Calcification in Type 1 Diabetes study. We used linear regression to analyze the association between serum protein levels and T1DM status using 47 healthy controls and 134 T1DM patients without CVD and Cox proportional hazards regression to assess their prediction for incident CVD by a case-cohort study using a subcohort of 145 T1DM subjects and a total of 47 CVD events. Of the 28 serum proteins studied, five of them-alpha-2-macroglobulin (A2M), apolipoprotein A-IV, apolipoprotein L1, insulin-like growth factor 2, and phospholipid transfer protein-were significantly associated with T1DM status, with A2M being 1.6-fold higher in T1DM. After adjusting for potential confounders, A2M independently predicted incident CVD, with a mean hazard ratio of 3.3 and 95% CI of 1.8-6.1. In our study, A2M showed the largest increase in serum levels when comparing patients with T1DM to control subjects. A2M also predicted incident CVD, suggesting that it could serve as both a marker and possibly a mediator of atherosclerosis in T1DM. These findings emphasize the importance of specific serum proteins in assessing and managing CVD risk in T1DM. Show less

Apolipoprotein A-V (APOA5) is a critical regulator of circulating triglyceride (TG) levels. Its deletion leads to elevated plasma TG concentrations by altering the metabolism of VLDL particles in vivo. One way APOA5 exerts its effects is through the modulation of LPL activity, specifically by disrupting inhibitory interactions between LPL and angiopoietin-like proteins (ANGPTLs). However, the impact of APOA5 on VLDL composition and its potential to alter VLDL metabolism in other ways remains poorly understood. To address this, we investigated the influence of APOA5 on the VLDL proteome, LPL activation, and hepatic remnant uptake. Using VLDL from Apoa5 KO and WT mice, we found no evidence that APOA5 directly enhances LPL activity in purified or plasma systems. However, VLDL from Apoa5 KO mice was cleared significantly more slowly by cultured hepatocytes. VLDL proteomics experiments from two independent laboratories identified altered contents of 23 proteins involved in lipoprotein metabolism, inflammation, and immune response in Apoa5 KO VLDL, including reductions in APOE and serum amyloid A1. Remarkably, reintroduction of recombinant mouse APOA5 to the KO plasma partially restored the WT VLDL proteome, including APOE, and normalized VLDL uptake by hepatocytes without altering LPL lipolysis. These findings reveal that APOA5 influences hepatic clearance of VLDL remnants by modulating particle composition, particularly APOE content. This study expands the functional scope of APOA5 in TG metabolism and underscores its role in VLDL remodeling and remnant clearance, offering new insights with implications for understanding hypertriglyceridemia and its roles in inflammation and immune response. Show less

The cholesteryl ester transfer protein inhibitor obicetrapib decreases levels of atherogenic lipids and raises high-density lipoprotein cholesterol (HDL-C). In this study, we sought to determine the effect of obicetrapib on cardiovascular events. The effects of 10 mg obicetrapib and placebo daily on major adverse cardiovascular event (MACE) rates were investigated in a pooled analysis of 354 patients with heterozygous familial hypercholesterolemia (HeFH) and 2,530 patients with atherosclerotic cardiovascular disease (ASCVD) over 365 days. The association between on-treatment lipids and MACE were also investigated. The cohort (mean age 66 years, 36% female, ASCVD 82%, HeFH 27%, diabetes 35%) had median baseline levels of low-density lipoprotein cholesterol (LDL-C) 92 mg/dL, HDL-C 48 mg/dL, apolipoprotein B (ApoB) 88 mg/dL, non-HDL-C 116 mg/dL, and lipoprotein(a) (Lp(a)) 40.5 nmol/L. Obicetrapib produced greater reductions in LDL-C (-34.0 vs -4.0 mg/dL, -37.8% vs -4.6%), ApoB (-19.0 vs -3.0 mg/dL, -21.7% vs -3.6%), non-HDL-C (-36.0 vs -4.0 mg/dL, -32.4% vs -3.7%), and Lp(a) (-9.8 vs 0 nmol/L, -32.5% vs 0%) and increased HDL-C (+68.0 vs +1.0 mg/dL, +140.0% vs +1.5%). The rate of coronary heart disease death, myocardial infarction, ischemic stroke, or coronary revascularization was lower with obicetrapib (3.9% vs 5.0%; HR: 0.77; 95% CI: 0.54-1.11; P = 0.16), with a risk reduction in the second 6 months (HR: 0.60; 95% CI: 0.37-0.99; P = 0.04). The rate of coronary heart disease death, myocardial infarction, or coronary revascularization was lower with obicetrapib (3.2% vs 4.7%; HR: 0.68; 95% CI: 0.46-1.00; P = 0.048), with a risk reduction in the second 6 months (HR: 0.45; 95% CI: 0.26-0.77; P = 0.003). Achieved levels of LDL-C (P = 0.003), ApoB (P = 0.007), non-HDL-C (P = 0.01), Lp(a) (P = 0.003), and HDL-C (P = 0.0001) were associated with event rates. Obicetrapib treatment associated with a reduction in coronary events, evident beyond 6 months of treatment. Show less

There exists a complex relationship between steatotic liver disease (SLD) and atherosclerotic cardiovascular disease (CVD). CVD is a leading cause of morbidity and mortality among individuals with SLD, particularly those with metabolic dysfunction-associated SLD (MASLD), a significant proportion of whom also exhibit features of insulin resistance. Recent evidence supports an expanded role of very low-density lipoprotein (VLDL) in the pathogenesis of CVD in patients, both with and without associated metabolic dysfunction. VLDL represents the major vehicle for exporting neutral lipid from hepatocytes, with each particle containing one molecule of apolipoproteinB100 (APOB100). VLDL production becomes dysregulated under conditions characteristic of MASLD including steatosis and insulin resistance. Insulin resistance not only affects VLDL production but also mediates the pathogenesis of atherosclerotic CVD. VLDL assembly and secretion therefore represents an important pathway in the setting of cardiometabolic disease and offers several candidates for therapeutic targeting, particularly in metabolically complex patients with MASLD at increased risk of atherosclerotic CVD. Here we review the clinical significance as well as the translational and therapeutic potential of key regulatory steps impacting VLDL initiation, maturation, secretion, catabolism, and clearance. Show less

Cardiovascular outcome trials are being considered for therapeutics that silence apolipoprotein C3 (APOC3) or angiopoietin-like 3 (ANGPTL3) because of their abilities to lower triglyceride-rich lipoproteins (TRLs) and their remnants in individuals with increased cardiovascular disease (CVD) risk Show less

Reducing LDL cholesterol prevents atherosclerotic cardiovascular disease (ASCVD) events. The aim of this study was to evaluate the LDL cholesterol-lowering efficacy of a fixed-dose combination (FDC) of obicetrapib, a CETP inhibitor, and ezetimibe. This randomised, double-blind trial across 48 US sites including hospitals, private and group practices, and independent research centres included participants at least 18 years old with pre-existing or high risk for ASVCD or heterozygous familial hypercholesterolaemia with LDL cholesterol concentrations of 1·8 mmol/L (70 mg/dL) or greater despite maximally tolerated lipid-lowering therapy excluding ezetimibe, or having statin intolerance. Participants were randomly assigned (1:1:1:1) to obicetrapib 10 mg plus ezetimibe 10 mg FDC, obicetrapib 10 mg monotherapy, ezetimibe 10 mg monotherapy, or placebo administered daily for 84 days. The co-primary endpoints in the intention-to-treat population were the percent LDL cholesterol changes in the FDC group compared with placebo, ezetimibe monotherapy, and obicetrapib monotherapy, and the placebo-adjusted change in the obicetrapib monotherapy group. The trial was prospectively registered (NCT06005597) and is completed. Between March 4 and July 3, 2024, 407 participants were randomly assigned. The median age was 68·0 years (IQR 62·0-73·0) and 177 (43%) were female. Mean baseline LDL cholesterol was 2·4 mmol/L, 2·5 mmol/L, 2·6 mmol/L, and 2·5 mmol/L in the placebo (n=102), ezetimibe monotherapy (n=101), obicetrapib monotherapy (n=102), and FDC groups (n=102), respectively. At day 84, percent differences in LDL cholesterol reduction with the FDC were -48·6% (95% CI -58·3 to -38·9) versus placebo, -27·9% (-37·5 to -18·4) versus ezetimibe, and -16·8% (-26·4 to -7·1) versus obicetrapib. Obicetrapib monotherapy decreased LDL cholesterol by 31·9% (22·1 to 41·6) versus placebo. Adverse event rates were similar in the FDC (52 [51%] of 102), obicetrapib (55 [54%] of 102), and ezetimibe (54 [53%] of 101) groups and lowest with placebo (38 [37%] of 102). Serious adverse event rates were generally similar across FDC (three [3%] of 102), obicetrapib (six [6%] of 102), ezetimibe (seven [7%] of 101), and placebo (four [4%] of 102) groups. Deaths occurred in one [1%] of 102 participants with FDC, one [1%] of 102 with obicetrapib, one [1%] of 101 with ezetimibe, and none with placebo. Combination therapy of obicetrapib and ezetimibe significantly reduced LDL cholesterol. This oral, single-pill therapy could improve LDL cholesterol management in patients with pre-existing or high risk for ASCVD. NewAmsterdam Pharma. Show less

The melanocyte lineage-determining Microphthalmia-associated transcription factor (MITF) drives proliferation and survival of melanocytic melanoma cells through regulation of both coding genes and long non-coding RNAs (LncRNAs). Here we characterize LINC00520 (hereafter called LncRNA ENhancer of Translation, LENT) regulated by MITF and strongly expressed in melanocytic melanoma cells. LENT is essential for the proliferation and survival of cultured melanocytic melanoma cells and xenograft tumors. LENT interacts with the G4 quadruplex resolvase DHX36, and both associate with the ribosome in the 80S and light polysome fractions. LENT modulates DHX36 association with a collection of mRNAs regulating their engagement with polysomes and fine-tuning their subsequent translation. These mRNAs encode proteins involved in endoplasmic reticulum (ER) and mitochondrial homeostasis as well as autophagy. Consequently, LENT silencing leads to extensive autophagy and mitophagy, compromised oxidative metabolic capacity, accompanied by an accumulation and mis-localization of mitochondrial proteins leading to proteotoxic stress and apoptosis. The LENT-DHX36 axis therefore fine-tunes translation of proteins involved in ER and mitochondrial homeostasis, suppressing autophagy and promoting survival and proliferation of melanoma cells. Show less

This study was aimed at assessing the diagnostic utility of whole genome sequence analysis in a well-characterised research cohort of individuals referred with a clinical suspicion of Cornelia de Lange syndrome (CdLS) in whom prior genetic testing had not identified a causative variant. Short-read whole genome sequencing was performed on 195 individuals from 105 families, 108 of whom were affected. 100/108 of the affected individuals had prior relevant genetic testing, with no pathogenic variant being identified. The study group comprised 42 trios in which both parental samples were available for testing (42 affected individuals and 126 unaffected parents), 61 singletons (unrelated affected individuals), and two families with more than one affected individual. The results showed that 32 unrelated probands from 105 families (30.5%) had likely causative coding region-disrupting variants. Four loci were identified in > 1 proband: Show less

Apolipoprotein A4 (APOA4) is synthesized by the small intestine in response to dietary lipids. Chronic exposure to a high-fat diet (HFD) desensitizes lipid-induced APOA4 production and attenuates brown adipose tissue (BAT) thermogenesis. We hypothesized that exogenous APOA4 could increase BAT thermogenesis and energy expenditure in HFD-fed mice, resulting in decreased obesity and improved glucose tolerance. BAT and inguinal white adipose tissue (IWAT) thermogenesis, body composition, energy intake and expenditure, and locomotor activity were measured using an infrared camera, immunoblots, quantitative magnetic resonance imaging, and a comprehensive lab animal monitoring system. An intraperitoneal glucose tolerance test and hepatic lipid accumulation and steatosis were assayed. Mice receiving continuous infusion of APOA4 for the last 4 weeks of 10 weeks of HFD feeding gained no additional body weight and had reduced fat mass but enhanced BAT and IWAT thermogenesis and energy expenditure, despite unaltered food intake and locomotor activity. Additionally, APOA4 infusion elevated fatty acid β oxidation; decreased lipogenesis, lipid accumulation, and steatosis in liver; and improved glucose tolerance. Maintenance of plasma APOA4 via exogenous APOA4 protein parallels elevation of BAT and IWAT thermogenesis, hepatic fatty acid β oxidation, and overall energy expenditure, with subsequent prevention of additional weight gain in HFD-fed obese mice. Show less

To review the evidence and describe the biological plausibility for the benefits of inhibiting cholesteryl ester transfer protein (CETP) on multiple organ systems through modification of lipoprotein metabolism. Results from observational studies, Mendelian randomization analyses, and randomized clinical trials support the potential of CETP inhibition to reduce atherosclerotic cardiovascular disease (ASCVD) risk through a reduction of apolipoprotein B-containing lipoproteins. In contrast, raising high-density lipoprotein (HDL) particles, as previously hypothesized, did not contribute to ASCVD risk reduction. There is also an expanding body of evidence supporting the benefits of CETP inhibition for safeguarding against other conditions associated with aging, particularly new-onset type 2 diabetes mellitus and dementia, as well as age-related macular degeneration, septicemia, and possibly chronic kidney disease. The latter are likely mediated through improved functionality of the HDL particle, including its role on cholesterol efflux and antioxidative, anti-inflammatory, and antimicrobial activities. At present, there is robust clinical evidence to support the benefits of reducing CETP activity for ASCVD risk reduction, and plausibility exists for the promotion of longevity by reducing risks of several other conditions. An ongoing large clinical trial program of the latest potent CETP inhibitor, obicetrapib, is expected to provide further insight into CETP inhibition as a therapeutic target for these various conditions. Show less

Anacetrapib, a cholesteryl ester transfer protein (CETP) inhibitor previously under development, exhibited an usually extended terminal half-life and large food effect and accumulated in adipose tissue. Other CETP inhibitors have not shown such effects. Obicetrapib, a potent selective CETP inhibitor, is undergoing Phase III clinical development. Dedicated assessments were conducted in pre-clinical and Phase I and II clinical studies of obicetrapib to examine the pharmacokinetic issues observed with anacetrapib. After 9 months of dosing up to 50 mg/kg/day in cynomolgus monkeys, obicetrapib was completely eliminated from systemic circulation and not detected in adipose tissue after a 13-week recovery period. In healthy humans receiving 1-25 mg of obicetrapib, the mean terminal half-life of obicetrapib was 148, 131, and 121 h at 5, 10, and 25 mg, respectively, and food increased plasma levels by ~1.6-fold with a 10 mg dose. At the end of treatment in Phase II trials, mean plasma levels of obicetrapib ranged from 194.5 ng/mL with 2.5 mg to 506.3 ng/mL with 10 mg. Plasma levels of obicetrapib decreased by 92.2% and 98.5% at four and 15 weeks post-treatment, respectively. Obicetrapib shows no clinically relevant accumulation, is minimally affected by food, and has a mean terminal half-life of 131 h for the 10 mg dose. These data support once daily, chronic dosing of obicetrapib in Phase III trials for dyslipidemia management. Show less

Elevated concentrations of low-density lipoprotein cholesterol (LDL-C) are linked to dementia risk, and conversely, increased plasma concentrations of high-density lipoprotein cholesterol (HDL-C) and apolipoprotein-A1 (Apo-A1) associate with decreased dementia risk. Inhibition of cholesteryl ester transfer protein (CETP) meaningfully affects the concentrations of these blood lipids and may therefore provide an opportunity to treat dementia. Drug target Mendelian randomization (MR) was employed to anticipate the on-target effects of lower CETP concentration (μg/mL) on plasma lipids, cardiovascular disease outcomes, autopsy confirmed Lewy body dementia (LBD), as well as Parkinson's dementia. MR analysis of lower CETP concentration recapitulated the blood lipid effects observed in clinical trials of CETP-inhibitors, as well as protective effects on coronary heart disease (odds ratio (OR) 0.92, 95% confidence interval (CI) 0.89; 0.96), heart failure, abdominal aortic aneurysm, any stroke, ischemic stroke, and small vessel stroke (0.90, 95%CI 0.85; 0.96). Consideration of dementia related traits indicated that lower CETP concentrations were associated higher total brain volume (0.04 per standard deviation, 95%CI 0.02; 0.06), lower risk of LBD (OR 0.81, 95%CI 0.74; 0.89) and Parkinson's dementia risk (OR 0.26, 95%CI 0.14; 0.48). APOE4 stratified analyses suggested the LBD effect was most pronounced in APOE-ε4 + participants (OR 0.61 95%CI 0.51; 0.73), compared to APOE-ε4- (OR 0.89 95%CI 0.79; 1.01); interaction p-value 5.81 × 10 These results suggest that inhibition of CETP may be a viable strategy to treat dementia, with a more pronounced effect expected in APOE-ε4 carriers. Show less

Obicetrapib is a selective cholesteryl ester transfer protein (CETP) inhibitor. Previous research has demonstrated similar pharmacokinetic (PK) responses to single doses of obicetrapib between Japanese and White males, but the PK responses have not been established in Chinese individuals. The purpose of this randomized, parallel, open-label trial was to characterize the PK and pharmacodynamic (PD; CETP activity and plasma lipids) responses and safety of single doses (5, 10, or 25 mg; N = 36) and multiple doses (10 mg for 14 days; N = 12) of obicetrapib in healthy Chinese individuals. The maximum concentration and area under the drug concentration-time curve of obicetrapib from 0 h to infinity increased with dose after all single doses of obicetrapib. After 7 consecutive days of dosing, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol reached their minimum and maximum changes of 42% reduction and 108% increase, respectively. Primary PK and PD parameters after single- and multiple-dose administration of obicetrapib were similar to those in healthy white participants in previous studies. One participant in the 5 mg dose group experienced a treatment-emergent adverse event of decreased white blood cell and neutrophil counts, which resolved without intervention. In conclusion, these findings support the inclusion of Chinese individuals in the ongoing phase 3 clinical development program of obicetrapib. Show less

Cholesteryl ester transfer protein (CETP) inhibitors, initially developed for treating hyperlipidemia, have shown promise in reducing the risk of new-onset diabetes during clinical trials. This positions CETP inhibitors as potential candidates for repurposing in metabolic disease treatment. Given their oral administration, they could complement existing oral medications like sodium-glucose cotransporter 2 (SGLT2) inhibitors, potentially delaying the need for injectable therapies such as insulin. We conducted a 2x2 factorial Mendelian Randomization analysis involving 233,765 participants from the UK Biobank. This study aimed to evaluate whether simultaneous genetic inhibition of CETP and SGLT2 enhances glycemic control compared to inhibiting each separately. Our findings indicate that dual genetic inhibition of CETP and SGLT2 significantly reduces glycated hemoglobin levels compared to controls and single-agent inhibition. Additionally, the combined inhibition is linked to a lower incidence of diabetes compared to both the control group and SGLT2 inhibition alone. These results suggest that combining CETP and SGLT2 inhibitor therapies may offer superior glycemic control over SGLT2 inhibitors alone. Future clinical trials should investigate the potential of repurposing CETP inhibitors for metabolic disease treatment, providing an oral therapeutic option that could benefit high-risk patients before they require injectable therapies like insulin or glucagon-like peptide-1 (GLP-1) receptor agonists. Show less

Obicetrapib, a novel, selective cholesteryl ester transfer protein (CETP) inhibitor, reduces low-density lipoprotein cholesterol (LDL-C), LDL particles, apolipoprotein (Apo) B, and lipoprotein(a) [Lp(a)] and increases high-density lipoprotein cholesterol (HDL-C) when added to statins with or without ezetimibe. By substantially reducing LDL-C, obicetrapib has the potential to lower atherogenic lipoproteins in patients with atherosclerotic cardiovascular disease (ASCVD) or heterozygous familial hypercholesterolemia (HeFH) whose LDL-C levels remain high despite treatment with available maximally tolerated lipid-modifying therapies, addressing an unmet medical need in a patient population at high risk for cardiovascular events. BROADWAY (NCT05142722) and BROOKLYN (NCT05425745) are ongoing placebo-controlled, double-blind, randomized Phase III trials designed to examine the efficacy, safety, and tolerability of obicetrapib as an adjunct to dietary intervention and maximally tolerated lipid-modifying therapies in participants with a history of ASCVD and/or underlying HeFH whose LDL-C is not adequately controlled. The primary efficacy endpoint was the percent change in LDL-C from baseline to day 84. Other endpoints included changes in Apo B, non-HDL-C, HDL-C, Apo A1, Lp(a), and triglycerides in addition to parameters evaluating safety, tolerability, and pharmacokinetics. BROADWAY also included an adjudicated assessment of major adverse cardiovascular events, measurements of glucose homeostasis, and an ambulatory blood pressure monitoring substudy. A total of 2,532 participants were randomized in BROADWAY and 354 in BROOKLYN to receive obicetrapib 10 mg or placebo (2:1) for 365 days with follow-up through 35 days after the last dose. Results from both trials are anticipated in 2024. These trials will provide safety and efficacy data to support the potential use of obicetrapib among patients with ASCVD or HeFH with elevated LDL-C for whom existing therapies are not sufficiently effective or well-tolerated. Show less

To discuss the history of cardiovascular outcomes trials of cholesteryl ester transfer protein (CETP) inhibitors and to describe obicetrapib, a next-generation, oral, once-daily, low-dose CETP inhibitor in late-stage development for dyslipidemia and atherosclerotic cardiovascular disease (ASCVD). Phase 1 and 2 trials have evaluated the safety and lipid/lipoprotein effects of obicetrapib as monotherapy, in conjunction with statins, on top of high-intensity statins (HIS), and with ezetimibe on top of HIS. In ROSE2, 10 mg obicetrapib monotherapy and combined with 10 mg ezetimibe, each on top of HIS, significantly reduced low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), apolipoprotein B, total LDL particles, small LDL particles, small, dense LDL-C, and lipoprotein (a), and increased HDL-C. Phase 3 pivotal registration trials including a cardiovascular outcomes trial are underway. Obicetrapib has an excellent safety and tolerability profile and robustly lowers atherogenic lipoproteins and raises HDL-C. As such, obicetrapib may be a promising agent for the treatment of ASCVD. Show less

Long-chain fatty acids induce apolipoprotein A4 (APOA4) production in the small intestine and activate brown adipose tissue (BAT) thermogenesis. The increase in BAT thermogenesis enhances triglyceride clearance and insulin sensitivity. Acute administration of recombinant APOA4 protein elevates BAT thermogenesis in chow-fed mice. However, the physiological role of continuous infusion of recombinant APOA4 protein in regulating sympathetic activity, thermogenesis, and lipid and glucose metabolism in low-fat-diet (LFD)-fed mice remained elusive. The hypothesis of this study was that continuous infusion of mouse APOA4 protein would increase sympathetic activity and thermogenesis in BAT and subcutaneous inguinal white adipose tissue (IWAT), attenuate plasma lipid levels, and improve glucose tolerance. To test this hypothesis, sympathetic activity, BAT temperature, energy expenditure, body weight, fat mass, caloric intake, glucose tolerance, and levels of BAT and IWAT thermogenic and lipolytic proteins, plasma lipids, and markers of fatty acid oxidation in the liver in mice with APOA4 or saline treatment were measured. Plasma APOA4 levels were elevated, BAT temperature and thermogenesis were upregulated, and plasma triglyceride (TG) levels were reduced, while body weight, fat mass, caloric intake, energy expenditure, and plasma cholesterol and leptin levels were comparable between APOA4- and saline-treated mice. Additionally, APOA4 infusion stimulated sympathetic activity in BAT and liver but not in IWAT. APOA4-treated mice had greater fatty acid oxidation but less TG content in the liver than saline-treated mice had. Plasma insulin in APOA4-treated mice was lower than that in saline-treated mice after a glucose challenge. In conclusion, continuous infusion of mouse APOA4 protein stimulated sympathetic activity in BAT and the liver, elevated BAT thermogenesis and hepatic fatty acid oxidation, and consequently attenuated levels of plasma and hepatic TG and plasma insulin without altering caloric intake, body weight gain and fat mass. Show less

Type 1 diabetes (T1D) results from an autoimmune attack of the pancreatic β cells that progresses to dysglycemia and symptomatic hyperglycemia. Current biomarkers to track this evolution are limited, with development of islet autoantibodies marking the onset of autoimmunity and metabolic tests used to detect dysglycemia. Therefore, additional biomarkers are needed to better track disease initiation and progression. Multiple clinical studies have used proteomics to identify biomarker candidates. However, most of the studies were limited to the initial candidate identification, which needs to be further validated and have assays developed for clinical use. Here we curate these studies to help prioritize biomarker candidates for validation studies and to obtain a broader view of processes regulated during disease development. This systematic review was registered with Open Science Framework (DOI 10.17605/OSF.IO/N8TSA). Using PRISMA guidelines, we conducted a systematic search of proteomics studies of T1D in the PubMed to identify putative protein biomarkers of the disease. Studies that performed mass spectrometry-based untargeted/targeted proteomic analysis of human serum/plasma of control, pre-seroconversion, post-seroconversion, and/or T1D-diagnosed subjects were included. For unbiased screening, 3 reviewers screened all the articles independently using the pre-determined criteria. A total of 13 studies met our inclusion criteria, resulting in the identification of 251 unique proteins, with 27 (11%) being identified across 3 or more studies. The circulating protein biomarkers were found to be enriched in complement, lipid metabolism, and immune response pathways, all of which are found to be dysregulated in different phases of T1D development. We found a subset of 3 proteins (C3, KNG1 & CFAH), 6 proteins (C3, C4A, APOA4, C4B, A2AP & BTD) and 7 proteins (C3, CLUS, APOA4, C6, A2AP, C1R & CFAI) have consistent regulation between multiple studies in samples from individuals at pre-seroconversion, post-seroconversion and post-diagnosis compared to controls, respectively, making them strong candidates for clinical assay development. Biomarkers analyzed in this systematic review highlight alterations in specific biological processes in T1D, including complement, lipid metabolism, and immune response pathways, and may have potential for further use in the clinic as prognostic or diagnostic assays. Show less