Rewiring Endothelial Sphingolipid Metabolism to Favor S1P Over Ceramide Protects From Coronary Atherosclerosis.

BACKGROUND: Growing evidence correlated changes in bioactive sphingolipids, particularly S1P (sphingosine-1-phosphate) and ceramides, with coronary artery diseases. Furthermore, specific plasma ceramide species can predict major cardiovascular events. Dysfunction of the endothelium lining lesion-prone areas plays a pivotal role in atherosclerosis. Yet, how sphingolipid metabolism and signaling change and contribute to endothelial dysfunction and atherosclerosis remain poorly understood. METHODS: We used an established model of coronary atherosclerosis in mice, combined with sphingolipidomics, RNA-sequencing, flow cytometry, and immunostaining to investigate the contribution of sphingolipid metabolism and signaling to endothelial cell (EC) activation and dysfunction. RESULTS: We demonstrated that hemodynamic stress induced an early metabolic rewiring towards endothelial sphingolipid de novo biosynthesis, favoring S1P signaling over ceramides as a protective response. This finding is a paradigm shift from the current belief that ceramide accrual contributes to endothelial dysfunction. The enzyme SPT (serine palmitoyltransferase) commences de novo biosynthesis of sphingolipids and is inhibited by NOGO-B (reticulon-4B), an ER membrane protein. Here, we showed that NOGO-B is upregulated by hemodynamic stress in myocardial EC of ApoE-/- mice and is expressed in the endothelium lining coronary lesions in mice and humans. We demonstrated that mice lacking NOGO-B specifically in EC (Nogo-A/BECKOApoE-/-) were resistant to coronary atherosclerosis development and progression, and mortality. Fibrous cap thickness was significantly increased in Nogo-A/BECKOApoE-/- mice and correlated with reduced necrotic core and macrophage infiltration. Mechanistically, the deletion of NOGO-B in EC sustained the rewiring of sphingolipid metabolism towards S1P, imparting an atheroprotective endothelial transcriptional signature. CONCLUSIONS: These data demonstrated that hemodynamic stress induced a protective rewiring of sphingolipid metabolism, favoring S1P over ceramide. NOGO-B deletion sustained the rewiring of sphingolipid metabolism toward S1P protecting EC from activation under hemodynamic stress and refraining coronary atherosclerosis. These findings also set forth the foundation for sphingolipid-based therapeutics to limit atheroprogression.

Regional Differences in the Small Intestinal Proteome of Control Mice and of Mice Lacking Lysosomal Acid Lipase.

The metabolic contribution of the small intestine (SI) is still unclear despite recent studies investigating the involvement of single cells in regional differences. Using untargeted proteomics, we identified regional characteristics of the three intestinal tracts of C57BL/6J mice and found that proteins abundant in the mouse ileum correlated with the high ileal expression of the corresponding genes in humans. In the SI of C57BL/6J mice, we also detected an increasing abundance of lysosomal acid lipase (LAL), which is responsible for degrading triacylglycerols and cholesteryl esters within the lysosome. LAL deficiency in patients and mice leads to lipid accumulation, gastrointestinal disturbances, and malabsorption. We previously demonstrated that macrophages massively infiltrated the SI of Lal-deficient (KO) mice, especially in the duodenum. Using untargeted proteomics (ProteomeXchange repository, data identifier PXD048378), we revealed a general inflammatory response and a common lipid-associated macrophage phenotype in all three intestinal segments of Lal KO mice, accompanied by a higher expression of GPNMB and concentrations of circulating sTREM2. However, only duodenal macrophages activated a metabolic switch from lipids to other pathways, which were downregulated in the jejunum and ileum of Lal KO mice. Our results provide new insights into the process of absorption in control mice and possible novel markers of LAL-D and/or systemic inflammation in LAL-D.

ASGR1 deficiency diverts lipids toward adipose tissue but results in liver damage during obesity.

BACKGROUND: Asialoglycoprotein receptor 1 (ASGR1), primarily expressed on hepatocytes, promotes the clearance and the degradation of glycoproteins, including lipoproteins, from the circulation. In humans, loss-of-function variants of ASGR1 are associated with a favorable metabolic profile and reduced incidence of cardiovascular diseases. The molecular mechanisms by which ASGR1 could affect the onset of metabolic syndrome and obesity are unclear. Therefore, here we investigated the contribution of ASGR1 in the development of metabolic syndrome and obesity. METHODS: ASGR1 deficient mice (ASGR1-/-) were subjected to a high-fat diet (45% Kcal from fat) for 20 weeks. The systemic metabolic profile, hepatic and visceral adipose tissue were characterized for metabolic and structural alterations, as well as for immune cells infiltration. RESULTS: ASGR1-/- mice present a hypertrophic adipose tissue with 41% increase in fat accumulation in visceral adipose tissue (VAT), alongside with alteration in lipid metabolic pathways. Intriguingly, ASGR1-/- mice exhibit a comparable response to an acute glucose and insulin challenge in circulation, coupled with notably decreased in circulating cholesterol levels. Although the liver of ASGR1-/- have similar lipid accumulation to the WT mice, they present elevated levels of liver inflammation and a decrease in mitochondrial function. CONCLUSION: ASGR1 deficiency impacts energetic homeostasis during obesity leading to improved plasma lipid levels but increased VAT lipid accumulation and liver damage.

The Cellular and Molecular Basis of Translational Immunometabolism.

The immune response requires major changes to metabolic processes, and indeed, energy metabolism and functional activation are fully integrated in immune cells to determine their ability to divide, differentiate, and carry out effector functions. Immune cell metabolism has therefore become an attractive target area for therapeutic purposes. A neglected aspect in the translation of immunometabolism is the critical connection between systemic and cellular metabolism. Here, we discuss the importance of understanding and manipulating the integration of systemic and immune cell metabolism through in-depth analysis of immune cell phenotype and function in human metabolic diseases and, in parallel, of the effects of conventional metabolic drugs on immune cell differentiation and function. We examine how the recent identification of selective metabolic programs operating in distinct immune cell subsets and functions has the potential to deliver tools for cell- and function-specific immunometabolic targeting.

Translational opportunities of single-cell biology in atherosclerosis.

The advent of single-cell biology opens a new chapter for understanding human biological processes and for diagnosing, monitoring, and treating disease. This revolution now reaches the field of cardiovascular disease (CVD). New technologies to interrogate CVD samples at single-cell resolution are allowing the identification of novel cell communities that are important in shaping disease development and direct towards new therapeutic strategies. These approaches have begun to revolutionize atherosclerosis pathology and redraw our understanding of disease development. This review discusses the state-of-the-art of single-cell analysis of atherosclerotic plaques, with a particular focus on human lesions, and presents the current resolution of cellular subpopulations and their heterogeneity and plasticity in relation to clinically relevant features. Opportunities and pitfalls of current technologies as well as the clinical impact of single-cell technologies in CVD patient care are highlighted, advocating for multidisciplinary and international collaborative efforts to join the cellular dots of CVD.

Genetic deletion of MMP12 ameliorates cardiometabolic disease by improving insulin sensitivity, systemic inflammation, and atherosclerotic features in mice.

BACKGROUND: Matrix metalloproteinase 12 (MMP12) is a macrophage-secreted protein that is massively upregulated as a pro-inflammatory factor in metabolic and vascular tissues of mice and humans suffering from cardiometabolic diseases (CMDs). However, the molecular mechanisms explaining the contributions of MMP12 to CMDs are still unclear. METHODS: We investigated the impact of MMP12 deficiency on CMDs in a mouse model that mimics human disease by simultaneously developing adipose tissue inflammation, insulin resistance, and atherosclerosis. To this end, we generated and characterized low-density lipoprotein receptor (Ldlr)/Mmp12-double knockout (DKO) mice fed a high-fat sucrose- and cholesterol-enriched diet for 16-20 weeks. RESULTS: DKO mice showed lower cholesterol and plasma glucose concentrations and improved insulin sensitivity compared with LdlrKO mice. Untargeted proteomic analyses of epididymal white adipose tissue revealed that inflammation- and fibrosis-related pathways were downregulated in DKO mice. In addition, genetic deletion of MMP12 led to alterations in immune cell composition and a reduction in plasma monocyte chemoattractant protein-1 in peripheral blood which indicated decreased low-grade systemic inflammation. Aortic en face analyses and staining of aortic valve sections demonstrated reduced atherosclerotic plaque size and collagen content, which was paralleled by an improved relaxation pattern and endothelial function of the aortic rings and more elastic aortic sections in DKO compared to LdlrKO mice. Shotgun proteomics revealed upregulation of anti-inflammatory and atheroprotective markers in the aortas of DKO mice, further supporting our data. In humans, MMP12 serum concentrations were only weakly associated with clinical and laboratory indicators of CMDs. CONCLUSION: We conclude that the genetic deletion of MMP12 ameliorates obesity-induced low-grade inflammation, white adipose tissue dysfunction, biomechanical properties of the aorta, and the development of atherosclerosis. Therefore, therapeutic strategies targeting MMP12 may represent a promising approach to combat CMDs.

Rhabdomyolysis or Severe Acute Hepatitis Associated with the Use of Red Yeast Rice Extracts: an Update from the Adverse Event Reporting Systems.

PURPOSE OF REVIEW: Elevated plasma levels of low-density lipoprotein cholesterol (LDL-C) are a major risk factor for atherosclerotic cardiovascular disease (ASCVD), and lowering LDL-C reduces the risk of cardiovascular adverse events. Among natural approaches known for their lipid-lowering properties, red yeast rice (RYR) has a cholesterol-lowering effect due to the presence of bioactive components (monacolins) that act by inhibiting the activity of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. In August 2018, the European Food Safety Authority (EFSA) concluded in its assessment of the use of RYR (further amended in June 2022) that monacolins from RYR raise significant safety concerns when used as a food supplement at a dose of 10 mg/day. In particular, individual cases of serious adverse effects of monacolins from RYR have been reported at intakes as low as 3 mg/day. The EFSA Panel pointed out several uncertainties regarding the available data. RECENT FINDINGS: We conducted an in-depth and updated analysis of the serious adverse events, with a focus on rhabdomyolysis and acute hepatitis, associated with the consumption of RYR. An analysis of the Food and Drug Administration reporting systems revealed a very small number of cases of rhabdomyolysis or severe acute hepatitis associated with RYR use. In addition, only a few case reports of these serious adverse events associated with RYR use have been published. Based on data from adverse event reporting systems and available case reports, the occurrence of rhabdomyolysis or severe acute hepatitis that could be associated with the use of RYR appears to be extremely rare compared to the occurrence with statins, which is rare to common.

Impact of metabolic disorders on the structural, functional, and immunological integrity of the blood-brain barrier: Therapeutic avenues.

Mounting evidence has linked the metabolic disease to neurovascular disorders and cognitive decline. Using a murine model of a high-fat high-sugar diet mimicking obesity-induced type 2 diabetes mellitus (T2DM) in humans, we show that pro-inflammatory mediators and altered immune responses damage the blood-brain barrier (BBB) structure, triggering a proinflammatory metabolic phenotype. We find that disruption to tight junctions and basal lamina due to loss of control in the production of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) causes BBB impairment. Together the disruption to the structural and functional integrity of the BBB results in enhanced transmigration of leukocytes across the BBB that could contribute to an initiation of a neuroinflammatory response through activation of microglia. Using a humanized in vitro model of the BBB and T2DM patient post-mortem brains, we show the translatable applicability of our results. We find a leaky BBB phenotype in T2DM patients can be attributed to a loss of junctional proteins through changes in inflammatory mediators and MMP/TIMP levels, resulting in increased leukocyte extravasation into the brain parenchyma. We further investigated therapeutic avenues to reduce and restore the BBB damage caused by HFHS-feeding. Pharmacological treatment with recombinant annexin A1 (hrANXA1) or reversion from a high-fat high-sugar diet to a control chow diet (dietary intervention), attenuated T2DM development, reduced inflammation, and restored BBB integrity in the animals. Given the rising incidence of diabetes worldwide, understanding metabolic-disease-associated brain microvessel damage is vital and the proposed therapeutic avenues could help alleviate the burden of these diseases.

The burden of hypercholesterolemia and ischemic heart disease in an ageing world.

Despite a general improvement in global health conditions in the last decades, cardiovascular diseases (CVDs) are still the first global cause of death and disability worldwide, with ischemic heart disease (IHD) being responsible for half of CVD deaths. Hypercholesterolemia is a major causal risk factor for IHD. Although the availability of effective cholesterol-lowering drugs largely increased in the last few years, we are still facing disparities in the awareness of dyslipidaemia as a CVD-associated risk factor and therefore in health expenditure among different world areas. Although no significant changes have been reported globally in the levels of plasma cholesterol in the last three decades, relevant differences among world areas according to their economic status can be observed. Only high-income countries have experienced an improvement in plasma lipid profile which translated into a substantial decrease in the deaths and disabilities due to IHD, whereas countries in other income groups showed no reduction or even an increase. As expected, most of the deaths for IHD attributable to high LDL-C occur in people aged 60 years and above, although significant differences can be observed according to income. Altogether these observations suggest the need for measures to reduce the gap in treating hypercholesterolemia among income groups, with special attention to women and older people.

Neutral effect of SGLT2 inhibitors on lipoprotein metabolism: From clinical evidence to molecular mechanisms.

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are effective, well-tolerated, and safe glucose-lowering compounds for patients with type 2 diabetes mellitus (T2DM). SGLT2i benefit encompasses protection from heart and kidney failure, independently of the presence of diabetes. In addition, SGLT2i consistently reduce the risk of hospitalization for heart failure and, although with some heterogeneity between specific members of the class, favourably affect the risk of cardiovascular outcomes. The molecular mechanisms underlying the cardiovascular favourable effect are not fully clarified. Studies testing the efficacy of SGLT2i in human cohorts and experimental models of atherosclerotic cardiovascular disease (ASCVD) have reported significant differences in circulating levels and composition of lipoprotein classes. In randomized clinical trials, small but significant increases in low-density lipoprotein cholesterol (LDL-C) levels have been observed, with a still undefined clinical significance; on the other hand, favourable (although modest) effects on high-density lipoprotein cholesterol (HDL-C) and triglycerides have been reported. At the molecular level, glycosuria may promote a starving-like state that ultimately leads to a metabolic improvement through the mobilization of fatty acids from the adipose tissue and their oxidation for the production of ketone bodies. This, however, may also fuel hepatic cholesterol synthesis, thus inhibiting atherogenic lipoprotein uptake from the liver. Long-term studies collecting detailed information on lipid-lowering therapies at baseline and during the trials with SGLT2i, as well as regularly monitoring lipid profiles are warranted to disentangle the potential implications of SGLT2i in modulating lipoprotein-mediated atherosclerotic cardiovascular risk.

Lack of ApoA-I in ApoEKO Mice Causes Skin Xanthomas, Worsening of Inflammation, and Increased Coronary Atherosclerosis in the Absence of Hyperlipidemia.

BACKGROUND: HDL (high-density lipoprotein) and its major protein component, apoA-I (apolipoprotein A-I), play a unique role in cholesterol homeostasis and immunity. ApoA-I deficiency in hyperlipidemic, atheroprone mice was shown to drive cholesterol accumulation and inflammatory cell activation/proliferation. The present study was aimed at investigating the impact of apoA-I deficiency on lipid deposition and local/systemic inflammation in normolipidemic conditions. METHODS: ApoE deficient mice, apoE/apoA-I double deficient (DKO) mice, DKO mice overexpressing human apoA-I, and C57Bl/6J control mice were fed normal laboratory diet until 30 weeks of age. Plasma lipids were quantified, atherosclerosis development at the aortic sinus and coronary arteries was measured, skin ultrastructure was evaluated by electron microscopy. Blood and lymphoid organs were characterized through histological, immunocytofluorimetric, and whole transcriptome analyses. RESULTS: DKO were characterized by almost complete HDL deficiency and by plasma total cholesterol levels comparable to control mice. Only DKO showed xanthoma formation and severe inflammation in the skin-draining lymph nodes, whose transcriptome analysis revealed a dramatic impairment in energy metabolism and fatty acid oxidation pathways. An increased presence of CD4+ T effector memory cells was detected in blood, spleen, and skin-draining lymph nodes of DKO. A worsening of atherosclerosis at the aortic sinus and coronary arteries was also observed in DKO versus apoE deficient. Human apoA-I overexpression in the DKO background was able to rescue the skin phenotype and halt atherosclerosis development. CONCLUSIONS: HDL deficiency, in the absence of hyperlipidemia, is associated with severe alterations of skin morphology, aortic and coronary atherosclerosis, local and systemic inflammation.

Defective lipid signalling caused by mutations in PIK3C2B underlies focal epilepsy.

Epilepsy is one of the most frequent neurological diseases, with focal epilepsy accounting for the largest number of cases. The genetic alterations involved in focal epilepsy are far from being fully elucidated. Here, we show that defective lipid signalling caused by heterozygous ultra-rare variants in PIK3C2B, encoding for the class II phosphatidylinositol 3-kinase PI3K-C2ß, underlie focal epilepsy in humans. We demonstrate that patients' variants act as loss-of-function alleles, leading to impaired synthesis of the rare signalling lipid phosphatidylinositol 3,4-bisphosphate, resulting in mTORC1 hyperactivation. In vivo, mutant Pik3c2b alleles caused dose-dependent neuronal hyperexcitability and increased seizure susceptibility, indicating haploinsufficiency as a key driver of disease. Moreover, acute mTORC1 inhibition in mutant mice prevented experimentally induced seizures, providing a potential therapeutic option for a selective group of patients with focal epilepsy. Our findings reveal an unexpected role for class II PI3K-mediated lipid signalling in regulating mTORC1-dependent neuronal excitability in mice and humans.

PCSK9 deficiency rewires heart metabolism and drives heart failure with preserved ejection fraction.

AIMS: PCSK9 is secreted into the circulation, mainly by the liver, and interacts with low-density lipoprotein receptor (LDLR) homologous and non-homologous receptors, including CD36, thus favouring their intracellular degradation. As PCSK9 deficiency increases the expression of lipids and lipoprotein receptors, thus contributing to cellular lipid accumulation, we investigated whether this could affect heart metabolism and function. METHODS AND RESULTS: Wild-type (WT), Pcsk9 KO, Liver conditional Pcsk9 KO and Pcsk9/Ldlr double KO male mice were fed for 20 weeks with a standard fat diet and then exercise resistance, muscle strength, and heart characteristics were evaluated. Pcsk9 KO presented reduced running resistance coupled to echocardiographic abnormalities suggestive of heart failure with preserved ejection fraction (HFpEF). Heart mitochondrial activity, following maximal coupled and uncoupled respiration, was reduced in Pcsk9 KO mice compared to WT mice and was coupled to major changes in cardiac metabolism together with increased expression of LDLR and CD36 and with lipid accumulation. A similar phenotype was observed in Pcsk9/Ldlr DKO, thus excluding a contribution for LDLR to cardiac impairment observed in Pcsk9 KO mice. Heart function profiling of the liver selective Pcsk9 KO model further excluded the involvement of circulating PCSK9 in the development of HFpEF, pointing to a possible role locally produced PCSK9. Concordantly, carriers of the R46L loss-of-function variant for PCSK9 presented increased left ventricular mass but similar ejection fraction compared to matched control subjects. CONCLUSION: PCSK9 deficiency impacts cardiac lipid metabolism in an LDLR independent manner and contributes to the development of HFpEF.

DDASSQ: An open-source, multiple peptide sequencing strategy for label free quantification based on an OpenMS pipeline in the KNIME analytics platform.

In this study we investigated the performance of a computational pipeline for protein identification and label free quantification (LFQ) of LC-MS/MS data sets from experimental animal tissue samples, as well as the impact of its specific peptide search combinatorial approach. The full pipeline workflow was composed of peptide search engine adapters based on different identification algorithms, in the frame of the open-source OpenMS software running within the KNIME analytics platform. Two different in silico tryptic digestion, database-search assisted approaches (X!Tandem and MS-GF+), de novo peptide sequencing based on Novor and consensus library search (SpectraST), were tested for the processing of LC-MS/MS raw data files obtained from proteomic LC-MS experiments done on proteolytic extracts from mouse ex vivo liver samples. The results from proteomic LFQ were compared to those based on the application of the two software tools MaxQuant and Proteome Discoverer for protein inference and label-free data analysis in shotgun proteomics. Data are available via ProteomeXchange with identifier PXD025097.

Fatty acid metabolism complements glycolysis in the selective regulatory T cell expansion during tumor growth.

The tumor microenvironment restrains conventional T cell (Tconv) activation while facilitating the expansion of Tregs. Here we showed that Tregs' advantage in the tumor milieu relies on supplemental energetic routes involving lipid metabolism. In murine models, tumor-infiltrating Tregs displayed intracellular lipid accumulation, which was attributable to an increased rate of fatty acid (FA) synthesis. Since the relative advantage in glucose uptake may fuel FA synthesis in intratumoral Tregs, we demonstrated that both glycolytic and oxidative metabolism contribute to Tregs' expansion. We corroborated our data in human tumors showing that Tregs displayed a gene signature oriented toward glycolysis and lipid synthesis. Our data support a model in which signals from the tumor microenvironment induce a circuitry of glycolysis, FA synthesis, and oxidation that confers a preferential proliferative advantage to Tregs, whose targeting might represent a strategy for cancer treatment.

Single systemic transfer of a human gene associated with exceptional longevity halts the progression of atherosclerosis and inflammation in ApoE knockout mice through a CXCR4-mediated mechanism.

AIMS: Here, we aimed to determine the therapeutic effect of longevity-associated variant (LAV)-BPIFB4 gene therapy on atherosclerosis. METHODS AND RESULTS: ApoE knockout mice (ApoE-/-) fed a high-fat diet were randomly allocated to receive LAV-BPIFB4, wild-type (WT)-BPIFB4, or empty vector via adeno-associated viral vector injection. The primary endpoints of the study were to assess (i) vascular reactivity and (ii) atherosclerotic disease severity, by Echo-Doppler imaging, histology and ultrastructural analysis. Moreover, we assessed the capacity of the LAV-BPIFB4 protein to shift monocyte-derived macrophages of atherosclerotic mice and patients towards an anti-inflammatory phenotype. LAV-BPIFB4 gene therapy rescued endothelial function of mesenteric and femoral arteries from ApoE-/- mice; this effect was blunted by AMD3100, a CXC chemokine receptor type 4 (CXCR4) inhibitor. LAV-BPIFB4-treated mice showed a CXCR4-mediated shift in the balance between Ly6Chigh/Ly6Clow monocytes and M2/M1 macrophages, along with decreased T cell proliferation and elevated circulating levels of interleukins IL-23 and IL-27. In vitro conditioning with LAV-BPIFB4 protein of macrophages from atherosclerotic patients resulted in a CXCR4-dependent M2 polarization phenotype. Furthermore, LAV-BPIFB4 treatment of arteries explanted from atherosclerotic patients increased the release of atheroprotective IL-33, while inhibiting the release of pro-inflammatory IL-1ß, inducing endothelial nitric oxide synthase phosphorylation and restoring endothelial function. Finally, significantly lower plasma BPIFB4 was detected in patients with pathological carotid stenosis (>25%) and intima media thickness >2 mm. CONCLUSION: Transfer of the LAV of BPIFB4 reduces the atherogenic process and skews macrophages towards an M2-resolving phenotype through modulation of CXCR4, thus opening up novel therapeutic possibilities in cardiovascular disease.

Efficacy and Safety of Volanesorsen (ISIS 304801): the Evidence from Phase 2 and 3 Clinical Trials.

PURPOSE OF REVIEW: To revise the clinical evidence supporting the use of volanesorsen as new lipid-lowering drug and to assess the efficacy and safety of volanesorsen (ISIS 304801) through a systematic review of the literature and a meta-analysis of the available phase 2 and phase 3 clinical studies. RECENT FINDINGS: The meta-analysis of three clinical studies comprising 11 arms (N = l 156 subjects, with 95 in the active-treated arm and 61 in the control one) shows that volanesorsen significantly affects plasma levels of triglycerides (TG) [MD = - 67.90%, 95%CI = - 85.32, - 50.48, P < 0.001], high-density lipoprotein cholesterol (HDL-C) [MD = 40.06%, 95%CI: 32.79, 47.34, P < 0.001], very-low-density lipoprotein cholesterol (VLDL-C) [MD = - 72.90%, 95%CI = - 82.73, - 63.07, P < 0.001], apolipoprotein B (Apo B) [MD = 8%, 95%CI = 2.17, 13.84, P = 0.007], Apo B-48 [MD = - 64.63, 95%CI = - 105.37, - 23.88, P = 0.002], ApoCIII [MD = - 74.83%, 95%CI = - 85.93, - 63.73, P < 0.001], and VLDL ApoCIII [MD = - 83.69%, 95%CI = - 94.08, - 73.29, P < 0.001], without significant impact on LDL-C [MD = 47.01%, 95%CI = - 1.31, 95.33, P = 0.057] levels. Treatment with volanesorsen was associated with an higher risk of injection site reaction (OR = 32.89, 95%CI = 7.97,135,74, P < 0.001) and with an increased risk of upper respiratory tract infections (OR = 10.58, 95%CI = 1.23, 90.93, P < 0.05) when compared to placebo. Volanesorsen has a relevant impact on plasma TG and related parameters without affecting LDL cholesterolemia and is associated with an acceptable safety profile.

Zc3h10 is a novel mitochondrial regulator.

Mitochondria are the energy-generating hubs of the cell. In spite of considerable advances, our understanding of the factors that regulate the molecular circuits that govern mitochondrial function remains incomplete. Using a genome-wide functional screen, we identify the poorly characterized protein Zinc finger CCCH-type containing 10 (Zc3h10) as regulator of mitochondrial physiology. We show that Zc3h10 is upregulated during physiological mitochondriogenesis as it occurs during the differentiation of myoblasts into myotubes. Zc3h10 overexpression boosts mitochondrial function and promotes myoblast differentiation, while the depletion of Zc3h10 results in impaired myoblast differentiation, mitochondrial dysfunction, reduced expression of electron transport chain (ETC) subunits, and blunted TCA cycle flux. Notably, we have identified a loss-of-function mutation of Zc3h10 in humans (Tyr105 to Cys105) that is associated with increased body mass index, fat mass, fasting glucose, and triglycerides. Isolated peripheral blood mononuclear cells from individuals homozygotic for Cys105 display reduced oxygen consumption rate, diminished expression of some ETC subunits, and decreased levels of some TCA cycle metabolites, which all together derive in mitochondrial dysfunction. Taken together, our study identifies Zc3h10 as a novel mitochondrial regulator.

PCSK9 deficiency reduces insulin secretion and promotes glucose intolerance: the role of the low-density lipoprotein receptor.

Aims: PCSK9 loss of function genetic variants are associated with lower low-density lipoprotein cholesterol but also with higher plasma glucose levels and increased risk of Type 2 diabetes mellitus. Here, we investigated the molecular mechanisms underlying this association. Methods and results: Pcsk9 KO, WT, Pcsk9/Ldlr double KO (DKO), Ldlr KO, albumin AlbCre+/Pcsk9LoxP/LoxP (liver-selective Pcsk9 knock-out mice), and AlbCre-/Pcsk9LoxP/LoxP mice were used. GTT, ITT, insulin and C-peptide plasma levels, pancreas morphology, and cholesterol accumulation in pancreatic islets were studied in the different animal models. Glucose clearance was significantly impaired in Pcsk9 KO mice fed with a standard or a high-fat diet for 20 weeks compared with WT animals; insulin sensitivity, however, was not affected. A detailed analysis of pancreas morphology of Pcsk9 KO mice vs. controls revealed larger islets with increased accumulation of cholesteryl esters, paralleled by increased insulin intracellular levels and decreased plasma insulin, and C-peptide levels. This phenotype was completely reverted in Pcsk9/Ldlr DKO mice implying the low-density lipoprotein receptor (LDLR) as the proprotein convertase subtilisin/kexin Type 9 (PCSK9) target responsible for the phenotype observed. Further studies in albumin AlbCre+/Pcsk9LoxP/LoxP mice, which lack detectable circulating PCSK9, also showed a complete recovery of the phenotype, thus indicating that circulating, liver-derived PCSK9, the principal target of monoclonal antibodies, does not impact beta-cell function and insulin secretion. Conclusion: PCSK9 critically controls LDLR expression in pancreas perhaps contributing to the maintenance of a proper physiological balance to limit cholesterol overload in beta cells. This effect is independent of circulating PCSK9 and is probably related to locally produced PCSK9.