Publications by authors named "Jesper Gromada"

107 Publications

Glucagon Receptor Inhibition Reduces Hyperammonemia and Lethality in Male Mice with Urea Cycle Disorder.

Endocrinology 2021 01;162(1)

Regeneron Pharmaceuticals, Tarrytown, New York USA.

The liver plays a critical role in maintaining ammonia homeostasis. Urea cycle defects, liver injury, or failure and glutamine synthetase (GS) deficiency result in hyperammonemia, serious clinical conditions, and lethality. In this study we used a mouse model with a defect in the urea cycle enzyme ornithine transcarbamylase (Otcspf-ash) to test the hypothesis that glucagon receptor inhibition using a monoclonal blocking antibody will reduce the hyperammonemia and associated lethality induced by a high-protein diet, which exacerbates disease. We found reduced expression of glutaminase, which degrades glutamine and increased expression of GS in livers of Otcspf-ash mice treated with the glucagon receptor blocking antibody. The gene expression changes favor ammonia consumption and were accompanied by increased circulating glutamine levels and diminished hyperammonemia. Otcspf-ash mice treated with the glucagon receptor-blocking antibody gained lean and body mass and had increased survival. These data suggest that glucagon receptor inhibition using a monoclonal antibody could reduce the risk for hyperammonemia and other clinical manifestations of patients suffering from defects in the urea cycle, liver injury, or failure and GS deficiency.
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http://dx.doi.org/10.1210/endocr/bqaa211DOI Listing
January 2021

Angiopoietin-like protein 3 governs LDL-cholesterol levels through endothelial lipase-dependent VLDL clearance.

J Lipid Res 2020 09 9;61(9):1271-1286. Epub 2020 Jul 9.

Regeneron Pharmaceuticals, Tarrytown, NY, USA

Angiopoietin-like protein (ANGPTL)3 regulates plasma lipids by inhibiting LPL and endothelial lipase (EL). ANGPTL3 inactivation lowers LDL-C independently of the classical LDLR-mediated pathway and represents a promising therapeutic approach for individuals with homozygous familial hypercholesterolemia due to mutations. Yet, how ANGPTL3 regulates LDL-C levels is unknown. Here, we demonstrate in hyperlipidemic humans and mice that ANGPTL3 controls VLDL catabolism upstream of LDL. Using kinetic, lipidomic, and biophysical studies, we show that ANGPTL3 inhibition reduces VLDL-lipid content and size, generating remnant particles that are efficiently removed from the circulation. This suggests that ANGPTL3 inhibition lowers LDL-C by limiting LDL particle production. Mechanistically, we discovered that EL is a key mediator of ANGPTL3's novel pathway. Our experiments revealed that, although dispensable in the presence of LDLR, EL-mediated processing of VLDL becomes critical for LDLR-independent particle clearance. In the absence of EL and LDLR, ANGPTL3 inhibition perturbed VLDL catabolism, promoted accumulation of atypical remnants, and failed to reduce LDL-C. Taken together, we uncover ANGPTL3 at the helm of a novel EL-dependent pathway that lowers LDL-C in the absence of LDLR.
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http://dx.doi.org/10.1194/jlr.RA120000888DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7469887PMC
September 2020

Discordance between GLP-1R gene and protein expression in mouse pancreatic islet cells.

J Biol Chem 2020 08 18;295(33):11529-11541. Epub 2020 Jun 18.

Duke Molecular Physiology Institute, Duke University, Durham, North Carolina, USA

The insulinotropic actions of glucagon-like peptide 1 receptor (GLP-1R) in β-cells have made it a useful target to manage type 2 diabetes. Metabolic stress reduces β-cell sensitivity to GLP-1, yet the underlying mechanisms are unknown. We hypothesized that expression is heterogeneous among β-cells and that metabolic stress decreases the number of GLP-1R-positive β-cells. Here, analyses of publicly available single-cell RNA-Seq sequencing (scRNASeq) data from mouse and human β-cells indicated that significant populations of β-cells do not express the gene, supporting heterogeneous GLP-1R expression. To check these results, we used complementary approaches employing FACS coupled with quantitative RT-PCR, a validated GLP-1R antibody, and flow cytometry to quantify GLP-1R promoter activity, gene expression, and protein expression in mouse α-, β-, and δ-cells. Experiments with reporter mice and a validated GLP-1R antibody indicated that >90% of the β-cells are GLP-1R positive, contradicting the findings with the scRNASeq data. α-cells did not express mRNA and δ-cells expressed mRNA but not protein. We also examined the expression patterns of GLP-1R in mouse models of metabolic stress. Multiparous female mice had significantly decreased β-cell expression, but no reduction in GLP-1R protein levels or GLP-1R-mediated insulin secretion. These findings suggest caution in interpreting the results of scRNASeq for low-abundance transcripts such as the incretin receptors and indicate that GLP-1R is widely expressed in β-cells, absent in α-cells, and expressed at the mRNA, but not protein, level in δ-cells.
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http://dx.doi.org/10.1074/jbc.RA120.014368DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7450118PMC
August 2020

Alirocumab, evinacumab, and atorvastatin triple therapy regresses plaque lesions and improves lesion composition in mice.

J Lipid Res 2020 03 16;61(3):365-375. Epub 2019 Dec 16.

Metabolic Health Research, The Netherlands Organization of Applied Scientific Research (TNO), Gaubius Laboratory, Leiden, The Netherlands

Atherosclerosis-related CVD causes nearly 20 million deaths annually. Most patients are treated after plaques develop, so therapies must regress existing lesions. Current therapies reduce plaque volume, but targeting all apoB-containing lipoproteins with intensive combinations that include alirocumab or evinacumab, monoclonal antibodies against cholesterol-regulating proprotein convertase subtilisin/kexin type 9 and angiopoietin-like protein 3, may provide more benefit. We investigated the effect of such lipid-lowering interventions on atherosclerosis in APOE*3-Leiden.CETP mice, a well-established model for hyperlipidemia. Mice were fed a Western-type diet for 13 weeks and thereafter matched into a baseline group (euthanized at 13 weeks) and five groups that received diet alone (control) or with treatment [atorvastatin; atorvastatin and alirocumab; atorvastatin and evinacumab; or atorvastatin, alirocumab, and evinacumab (triple therapy)] for 25 weeks. We measured effects on cholesterol levels, plaque composition and morphology, monocyte adherence, and macrophage proliferation. All interventions reduced plasma total cholesterol (37% with atorvastatin to 80% with triple treatment; all < 0.001). Triple treatment decreased non-HDL-C to 1.0 mmol/l (91% difference from control; < 0.001). Atorvastatin reduced atherosclerosis progression by 28% versus control ( < 0.001); double treatment completely blocked progression and diminished lesion severity. Triple treatment regressed lesion size versus baseline in the thoracic aorta by 50% and the aortic root by 36% (both < 0.05 vs. baseline), decreased macrophage accumulation through reduced proliferation, and abated lesion severity. Thus, high-intensive cholesterol-lowering triple treatment targeting all apoB-containing lipoproteins regresses atherosclerotic lesion area and improves lesion composition in mice, making it a promising potential approach for treating atherosclerosis.
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http://dx.doi.org/10.1194/jlr.RA119000419DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7053846PMC
March 2020

Clinical and Molecular Prevalence of Lipodystrophy in an Unascertained Large Clinical Care Cohort.

Diabetes 2020 02 13;69(2):249-258. Epub 2019 Dec 13.

Regeneron Genetics Center, Regeneron Pharmaceuticals, Inc., Tarrytown, NY.

Lipodystrophies are a group of disorders characterized by absence or loss of adipose tissue and abnormal fat distribution, commonly accompanied by metabolic dysregulation. Although considered rare disorders, their prevalence in the general population is not well understood. We aimed to evaluate the clinical and genetic prevalence of lipodystrophy disorders in a large clinical care cohort. We interrogated the electronic health record (EHR) information of >1.3 million adults from the Geisinger Health System for lipodystrophy diagnostic codes. We estimate a clinical prevalence of disease of 1 in 20,000 individuals. We performed genetic analyses in individuals with available genomic data to identify variants associated with inherited lipodystrophies and examined their EHR for comorbidities associated with lipodystrophy. We identified 16 individuals carrying the p.R482Q pathogenic variant in LMNA associated with Dunnigan familial partial lipodystrophy. Four had a clinical diagnosis of lipodystrophy, whereas the remaining had no documented clinical diagnosis despite having accompanying metabolic abnormalities. We observed a lipodystrophy-associated variant carrier frequency of 1 in 3,082 individuals in our cohort with substantial burden of metabolic dysregulation. We estimate a genetic prevalence of disease of ∼1 in 7,000 in the general population. Partial lipodystrophy is an underdiagnosed condition. and its prevalence, as defined molecularly, is higher than previously reported. Genetically guided stratification of patients with common metabolic disorders, like diabetes and dyslipidemia, is an important step toward precision medicine.
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http://dx.doi.org/10.2337/db19-0447DOI Listing
February 2020

Loss of ZnT8 function protects against diabetes by enhanced insulin secretion.

Nat Genet 2019 11 1;51(11):1596-1606. Epub 2019 Nov 1.

Institute for Molecular Medicine Finland, Helsinki University, Helsinki, Finland.

A rare loss-of-function allele p.Arg138* in SLC30A8 encoding the zinc transporter 8 (ZnT8), which is enriched in Western Finland, protects against type 2 diabetes (T2D). We recruited relatives of the identified carriers and showed that protection was associated with better insulin secretion due to enhanced glucose responsiveness and proinsulin conversion, particularly when compared with individuals matched for the genotype of a common T2D-risk allele in SLC30A8, p.Arg325. In genome-edited human induced pluripotent stem cell (iPSC)-derived β-like cells, we establish that the p.Arg138* allele results in reduced SLC30A8 expression due to haploinsufficiency. In human β cells, loss of SLC30A8 leads to increased glucose responsiveness and reduced K channel function similar to isolated islets from carriers of the T2D-protective allele p.Trp325. These data position ZnT8 as an appealing target for treatment aimed at maintaining insulin secretion capacity in T2D.
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http://dx.doi.org/10.1038/s41588-019-0513-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6858874PMC
November 2019

Heterogeneity of human pancreatic β-cells.

Mol Metab 2019 09;27S:S7-S14

Exonics Therapeutics, Inc, 490 Arsenal Way, Watertown, MA, 02472, USA. Electronic address:

Background: Human pancreatic β-cells are heterogeneous. This has been known for a long time and is based on various functional and morphological readouts. β-Cell heterogeneity could reflect fixed subpopulations with distinct functions. However, recent pseudotime analysis of large-scale RNA sequencing data suggest that human β-cell subpopulations may rather reflect dynamic interchangeable states characterized by low expression of genes involved in the unfolded protein response (UPR) and low insulin gene expression, low UPR and high insulin expression or high UPR and low insulin expression.

Scope Of Review: This review discusses findings obtained by single-cell RNA sequencing combined with pseudotime analysis that human β-cell heterogeneity represents dynamic interchangeable functional states. The physiological significance and potential implications of β-cell heterogeneity in the development and progression of diabetes is highlighted.

Major Conclusions: The existence of dynamic functional states allow β-cells to transition between periods of high insulin production and UPR-mediated stress recovery. The recovery state is important since proinsulin is a misfolding-prone protein, making its biosynthesis in the endoplasmic reticulum a stressful event. The transition of β-cells between dynamic states is likely controlled at multiple levels and influenced by the microenvironment within the pancreatic islets. Disturbances in the ability of the β-cells to transition between periods of high insulin biosynthesis and UPR-mediated stress recovery may contribute to diabetes development. Diabetes medications that restore the ability of the β-cells to transition between the functional states should be considered.
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http://dx.doi.org/10.1016/j.molmet.2019.06.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6768494PMC
September 2019

RNA-sequencing reveals altered skeletal muscle contraction, E3 ligases, autophagy, apoptosis, and chaperone expression in patients with critical illness myopathy.

Skelet Muscle 2019 04 16;9(1). Epub 2019 Apr 16.

Department of Physiology and Pharmacology, Karolinska Institutet, Bioclinicum, J8:30, SE-171 77, Stockholm, Sweden.

Background: Critical illness myopathy (CIM) is associated with severe skeletal muscle wasting and impaired function in intensive care unit (ICU) patients. The mechanisms underlying CIM remain incompletely understood. To elucidate the biological activities occurring at the transcriptional level in the skeletal muscle of ICU patients with CIM, the gene expression profiles, potential upstream regulators, and enrichment pathways were characterized using RNA sequencing (RNA-seq). We also compared the skeletal muscle gene signatures in ICU patients with CIM and genes perturbed by mechanical loading in one leg of the ICU patients, with an aim of reducing the loss of muscle function.

Methods: RNA-seq was used to assess gene expression changes in tibialis anterior skeletal muscle samples from seven critically ill, immobilized, and mechanically ventilated ICU patients with CIM and matched control subjects. We also examined skeletal muscle gene expression for both legs of six ICU patients with CIM, where one leg was mechanically loaded for 10 h/day for an average of 9 days.

Results: In total, 6257 of 17,221 detected genes were differentially expressed (84% upregulated; p < 0.05 and fold change ≥ 1.5) in skeletal muscle from ICU patients with CIM when compared to control subjects. The differentially expressed genes were highly associated with gene changes identified in patients with myopathy, sepsis, long-term inactivity, polymyositis, tumor, and repeat exercise resistance. Upstream regulator analysis revealed that the CIM signature could be a result of the activation of MYOD1, p38 MAPK, or treatment with dexamethasone. Passive mechanical loading only reversed expression of 0.74% of the affected genes (46 of 6257 genes).

Conclusions: RNA-seq analysis revealed that the marked muscle atrophy and weakness observed in ICU patients with CIM were associated with the altered expression of genes involved in muscle contraction, newly identified E3 ligases, autophagy and calpain systems, apoptosis, and chaperone expression. In addition, MYOD1, p38 MAPK, and dexamethasone were identified as potential upstream regulators of skeletal muscle gene expression in ICU patients with CIM. Mechanical loading only marginally affected the skeletal muscle transcriptome profiling of ICU patients diagnosed with CIM.
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http://dx.doi.org/10.1186/s13395-019-0194-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6466682PMC
April 2019

Increased SLC38A4 Amino Acid Transporter Expression in Human Pancreatic α-Cells After Glucagon Receptor Inhibition.

Endocrinology 2019 05;160(5):979-988

Regeneron Pharmaceuticals, Inc., Tarrytown, New York.

Plasma amino acids and their transporters constitute an important part of the feedback loop between the liver and pancreatic α-cell function, and glucagon regulates hepatic amino acid turnover. Disruption of hepatic glucagon receptor action activates the loop and results in high plasma amino acids and hypersecretion of glucagon associated with α-cell hyperplasia. In the present study, we report a technique to rescue implanted human pancreatic islets from the mouse kidney capsule. Using this model, we have demonstrated that expression of the amino acid transporter SLC38A4 increases in α-cells after administration of a glucagon receptor blocking antibody. The increase in SLC38A4 expression and associated α-cell proliferation was dependent on mechanistic target of rapamycin pathway. We confirmed increased α-cell proliferation and expression of SLC38A4 in pancreas sections from patients with glucagon cell hyperplasia and neoplasia (GCHN) with loss-of-function mutations in the glucagon receptor. Collectively, using a technique to rescue implanted human islets from the kidney capsule in mice and pancreas sections from patients with GCHN, we found that expression of SLC38A4 was increased under conditions of disrupted glucagon receptor signaling. These data provide support for the existence of a liver-human α-cell endocrine feedback loop.
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http://dx.doi.org/10.1210/en.2019-00022DOI Listing
May 2019

The Liver-α-Cell Axis and Type 2 Diabetes.

Endocr Rev 2019 10;40(5):1353-1366

Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.

Both type 2 diabetes (T2D) and nonalcoholic fatty liver disease (NAFLD) strongly associate with increasing body mass index, and together these metabolic diseases affect millions of individuals. In patients with T2D, increased secretion of glucagon (hyperglucagonemia) contributes to diabetic hyperglycemia as proven by the significant lowering of fasting plasma glucose levels following glucagon receptor antagonist administration. Emerging data now indicate that the elevated plasma concentrations of glucagon may also be associated with hepatic steatosis and not necessarily with the presence or absence of T2D. Thus, fatty liver disease, most often secondary to overeating, may result in impaired amino acid turnover, leading to increased plasma concentrations of certain glucagonotropic amino acids (e.g., alanine). This, in turn, causes increased glucagon secretion that may help to restore amino acid turnover and ureagenesis, but it may eventually also lead to increased hepatic glucose production, a hallmark of T2D. Early experimental findings support the hypothesis that hepatic steatosis impairs glucagon's actions on amino acid turnover and ureagenesis. Hepatic steatosis also impairs hepatic insulin sensitivity and clearance that, together with hyperglycemia and hyperaminoacidemia, lead to peripheral hyperinsulinemia; systemic hyperinsulinemia may itself contribute to worsen peripheral insulin resistance. Additionally, obesity is accompanied by an impaired incretin effect, causing meal-related glucose intolerance. Lipid-induced impairment of hepatic sensitivity, not only to insulin but potentially also to glucagon, resulting in both hyperinsulinemia and hyperglucagonemia, may therefore contribute to the development of T2D at least in a subset of individuals with NAFLD.
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http://dx.doi.org/10.1210/er.2018-00251DOI Listing
October 2019

Hepatic Glucagon Signaling Regulates PCSK9 and Low-Density Lipoprotein Cholesterol.

Circ Res 2019 01;124(1):38-51

From the Department of Medicine, Columbia University, New York (S.S., W.D., J.A.Z., L.O.).

Rationale: Glucagon is a key hormone that regulates the adaptive metabolic responses to fasting. In addition to maintaining glucose homeostasis, glucagon participates in the regulation of cholesterol metabolism; however, the molecular pathways underlying this effect are incompletely understood.

Objective: We sought to determine the role of hepatic Gcgr (glucagon receptor) signaling in plasma cholesterol regulation and identify its underlying molecular mechanisms.

Methods And Results: We show that Gcgr signaling plays an essential role in LDL-C (low-density lipoprotein cholesterol) homeostasis through regulating the PCSK9 (proprotein convertase subtilisin/kexin type 9) levels. Silencing of hepatic Gcgr or inhibition of glucagon action increased hepatic and plasma PCSK9 and resulted in lower LDLR (LDL receptor) protein and increased plasma LDL-C. Conversely, treatment of wild-type (WT) mice with glucagon lowered LDL-C levels, whereas this response was abrogated in Pcsk9 and Ldlr mice. Our gain- and loss-of-function studies identified Epac2 (exchange protein activated by cAMP-2) and Rap1 (Ras-related protein-1) as the downstream mediators of glucagon's action on PCSK9 homeostasis. Moreover, mechanistic studies revealed that glucagon affected the half-life of PCSK9 protein without changing the level of its mRNA, indicating that Gcgr signaling regulates PCSK9 degradation.

Conclusions: These findings provide novel insights into the molecular interplay between hepatic glucagon signaling and lipid metabolism and describe a new posttranscriptional mechanism of PCSK9 regulation.
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http://dx.doi.org/10.1161/CIRCRESAHA.118.313648DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6457439PMC
January 2019

Gene Signature of the Human Pancreatic ε Cell.

Endocrinology 2018 12;159(12):4023-4032

Regeneron Pharmaceuticals, Inc., Tarrytown, New York.

The ghrelin-producing ε cell represents the fifth endocrine cell type in human pancreatic islets. The abundance of ε cells in adult pancreas is extremely low, which has hampered the investigation on the molecular pathways regulating the development and the function of this cell type. In this study, we explored the molecular features defining the function of pancreatic ε cells isolated from adult nondiabetic donors using single-cell RNA sequencing technology. We focus on transcription factors, cell surface receptors, and genes involved in metabolic pathways that contribute to regulation of cellular function. Furthermore, the genes that separate ε cells from the other islet endocrine cell types are presented. This study expands prior knowledge about the genes important for ε cell functioning during development and provides a resource to interrogate the transcriptome of this rare human islet cell type.
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http://dx.doi.org/10.1210/en.2018-00833DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6963699PMC
December 2018

Characterization of glucose-stimulated insulin release protocols in african green monkeys (Chlorocebus aethiops).

J Med Primatol 2019 02 25;48(1):10-21. Epub 2018 Oct 25.

RxGen Inc., New Haven, Connecticut.

Background: Management of diabetes remains a major health and economic challenge, demanding test systems in which to develop new therapies. These studies assessed different methodologies for determining glucose tolerance in green monkeys.

Methods: Twenty-eight African green monkeys between 4 and 24 years old underwent single or repeat intravenous glucose tolerance testing (IVGTT), oral glucose tolerance testing (OGTT), and/or graded glucose infusion testing.

Results: Geriatric monkeys exhibited glucose intolerance with impaired glucose-stimulated insulin secretion following IVGTT. Repeat IVGTT and OGTT assessments were inconsistent. Monkeys with low glucose-stimulated insulin secretion after graded glucose infusion exhibited elevated blood glucose levels.

Conclusion: IVGTT and graded glucose infusion protocols revealed differences in glucose tolerance among green monkeys at single time points, including age-dependent differences suggestive of shifts in pancreatic beta-cell functional capacity, but care should be applied to study design and the interpretation of data in the setting of longitudinal studies.
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http://dx.doi.org/10.1111/jmp.12374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6587791PMC
February 2019

The α-cell in diabetes mellitus.

Nat Rev Endocrinol 2018 12;14(12):694-704

Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK.

Findings from the past 10 years have placed the glucagon-secreting pancreatic α-cell centre stage in the development of diabetes mellitus, a disease affecting almost one in every ten adults worldwide. Glucagon secretion is reduced in patients with type 1 diabetes mellitus, increasing the risk of insulin-induced hypoglycaemia, but is enhanced in type 2 diabetes mellitus, exacerbating the effects of diminished insulin release and action on blood levels of glucose. A better understanding of the mechanisms underlying these changes is therefore an important goal. RNA sequencing reveals that, despite their opposing roles in the control of blood levels of glucose, α-cells and β-cells have remarkably similar patterns of gene expression. This similarity might explain the fairly facile interconversion between these cells and the ability of the α-cell compartment to serve as a source of new β-cells in models of extreme β-cell loss that mimic type 1 diabetes mellitus. Emerging data suggest that GABA might facilitate this interconversion, whereas the amino acid glutamine serves as a liver-derived factor to promote α-cell replication and maintenance of α-cell mass. Here, we survey these developments and their therapeutic implications for patients with diabetes mellitus.
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http://dx.doi.org/10.1038/s41574-018-0097-yDOI Listing
December 2018

Mice harboring the human R138X loss-of-function mutation have increased insulin secretory capacity.

Proc Natl Acad Sci U S A 2018 08 23;115(32):E7642-E7649. Epub 2018 Jul 23.

Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591;

encodes a zinc transporter that is primarily expressed in the pancreatic islets of Langerhans. In β-cells it transports zinc into insulin-containing secretory granules. Loss-of-function (LOF) mutations in protect against type 2 diabetes in humans. In this study, we generated a knockin mouse model carrying one of the most common human LOF mutations for , R138X. The R138X mice had normal body weight, glucose tolerance, and pancreatic β-cell mass. Interestingly, in hyperglycemic conditions induced by the insulin receptor antagonist S961, the R138X mice showed a 50% increase in insulin secretion. This effect was not associated with enhanced β-cell proliferation or mass. Our data suggest that the R138X LOF mutation may exert beneficial effects on glucose metabolism by increasing the capacity of β-cells to secrete insulin under hyperglycemic conditions.
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http://dx.doi.org/10.1073/pnas.1721418115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6094147PMC
August 2018

Gene Signature of Proliferating Human Pancreatic α Cells.

Endocrinology 2018 09;159(9):3177-3186

Regeneron Pharmaceuticals, Inc., Tarrytown, New York.

Pancreatic α cells proliferate at a low rate, and little is known about the control of this process. Here we report the characterization of human α cells by large-scale, single-cell RNA sequencing coupled with pseudotime ordering. We identified two large subpopulations and a smaller cluster of proliferating α cells with increased expression of genes involved in cell-cycle regulation. The proliferating α cells were differentiated, had normal levels of GCG expression, and showed no signs of cellular stress. Proliferating α cells were detected in both the G1S and G2M phases of the cell cycle. Human α cells proliferate at a fivefold higher rate than human β cells and express lower levels of the cell-cycle inhibitors CDKN1A and CDKN1C. Collectively, this study provides the gene signatures of human α cells and the genes involved in their cell division. The lower expression of two cell-cycle inhibitors in human α cells could account for their higher rate of proliferation compared with their insulin-producing counterparts.
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http://dx.doi.org/10.1210/en.2018-00469DOI Listing
September 2018

Pseudotime Ordering of Single Human β-Cells Reveals States of Insulin Production and Unfolded Protein Response.

Diabetes 2018 09 27;67(9):1783-1794. Epub 2018 Jun 27.

Regeneron Pharmaceuticals, Tarrytown, NY

Proinsulin is a misfolding-prone protein, making its biosynthesis in the endoplasmic reticulum (ER) a stressful event. Pancreatic β-cells overcome ER stress by activating the unfolded protein response (UPR) and reducing insulin production. This suggests that β-cells transition between periods of high insulin biosynthesis and UPR-mediated recovery from cellular stress. We now report the pseudotime ordering of single β-cells from humans without diabetes detected by large-scale RNA sequencing. We identified major states with ) low UPR and low insulin gene expression, ) low UPR and high insulin gene expression, or ) high UPR and low insulin gene expression. The latter state was enriched for proliferating cells. Stressed human β-cells do not dedifferentiate and show little propensity for apoptosis. These data suggest that human β-cells transition between states with high rates of biosynthesis to fulfill the body's insulin requirements to maintain normal blood glucose levels and UPR-mediated recovery from ER stress due to high insulin production.
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http://dx.doi.org/10.2337/db18-0365DOI Listing
September 2018

Genetic inactivation of ANGPTL4 improves glucose homeostasis and is associated with reduced risk of diabetes.

Nat Commun 2018 06 13;9(1):2252. Epub 2018 Jun 13.

Regeneron Pharmaceuticals, Tarrytown, 10591, NY, USA.

Angiopoietin-like 4 (ANGPTL4) is an endogenous inhibitor of lipoprotein lipase that modulates lipid levels, coronary atherosclerosis risk, and nutrient partitioning. We hypothesize that loss of ANGPTL4 function might improve glucose homeostasis and decrease risk of type 2 diabetes (T2D). We investigate protein-altering variants in ANGPTL4 among 58,124 participants in the DiscovEHR human genetics study, with follow-up studies in 82,766 T2D cases and 498,761 controls. Carriers of p.E40K, a variant that abolishes ANGPTL4 ability to inhibit lipoprotein lipase, have lower odds of T2D (odds ratio 0.89, 95% confidence interval 0.85-0.92, p = 6.3 × 10), lower fasting glucose, and greater insulin sensitivity. Predicted loss-of-function variants are associated with lower odds of T2D among 32,015 cases and 84,006 controls (odds ratio 0.71, 95% confidence interval 0.49-0.99, p = 0.041). Functional studies in Angptl4-deficient mice confirm improved insulin sensitivity and glucose homeostasis. In conclusion, genetic inactivation of ANGPTL4 is associated with improved glucose homeostasis and reduced risk of T2D.
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http://dx.doi.org/10.1038/s41467-018-04611-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5997992PMC
June 2018

Corrigendum to 'Inositol hexakisphosphate kinase 1 is a metabolic sensor in pancreatic β-cells' [Cellular Signalling 46 (2018) 120-128].

Cell Signal 2019 Jan 25;53:415. Epub 2018 May 25.

The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-171 76 Stockholm, Sweden; School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea. Electronic address:

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http://dx.doi.org/10.1016/j.cellsig.2018.05.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6293315PMC
January 2019

Preemptive Activation of the Integrated Stress Response Protects Mice From Diet-Induced Obesity and Insulin Resistance by Fibroblast Growth Factor 21 Induction.

Hepatology 2018 12 5;68(6):2167-2181. Epub 2018 Nov 5.

Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY.

Integrated stress response (ISR) is a signaling system in which phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) by stress-specific kinases and subsequent activation of activation transcription factor (ATF) 4 help restore cellular homeostasis following exposure to environmental stresses. ISR activation has been observed in metabolic diseases, including hepatic steatosis (HS), steatohepatitis (SH), and insulin resistance (IR), but it remains unclear whether ISR contributes to disease pathogenesis or represents an innate defense mechanism against metabolic stresses. Constitutive repressor of eIF2α phosphorylation (CReP) is a critical regulatory subunit of the eIF2α phosphatase complex. Here, we show that CReP ablation causes constitutive eIF2α phosphorylation in the liver, which leads to activation of the ATF4 transcriptional program including increased fibroblast growth factor 21 (FGF21) production. Liver-specific CReP knockout (CReP ) mice exhibited marked browning of white adipose tissue (WAT) and increased energy expenditure and insulin sensitivity in an FGF21-dependent manner. Furthermore, CReP mice were protected from high-fat diet (HFD)-induced obesity, HS, and IR. Acute CReP ablation in liver of HFD-induced obese mice also reduced adiposity and improved glucose homeostasis. Conclusion: These data suggest that CReP abundance is a critical determinant for eIF2α phosphorylation and ensuing ISR activation in the liver. Constitutive ISR activation in the liver induces FGF21 and confers protection from HFD-induced adiposity, IR, and HS in mice. Augmenting hepatic ISR may represent a therapeutic approach to treat metabolic disorders.
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http://dx.doi.org/10.1002/hep.30060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6203669PMC
December 2018

A Protein-Truncating HSD17B13 Variant and Protection from Chronic Liver Disease.

N Engl J Med 2018 03;378(12):1096-1106

From the Regeneron Genetics Center (N.S.A.-H., A.H.L., C.S., S. McCarthy, C.O., J.S.P., S.B., N.G., S. Mukherjee, A.E.L., E.D.F., J.P., I.B.B., A.R.S., J.G.R., J.D.O., O.G., T.M.T., A.B., F.E.D.) and Regeneron Pharmaceuticals (X. Cheng, Y.X., P.S., Y.L., D.E., S.Y.K., B.Z., W.O., A.J.M., G.D.Y., J.G.), Tarrytown, NY; the University of Texas Southwestern Medical Center at Dallas, Dallas (J.K., S.S., H.H.H., J.C.C.); and Geisinger Health System, Danville (G.C.W., A.N.S., M.D.S., X. Chu, J.Z.L., U.L.M., D.J.C., C.D.S., T.M.), and Perelman School of Medicine, University of Pennsylvania, Philadelphia (M.D.F., A.S., S.M.D., D.J.R.) - both in Pennsylvania.

Background: Elucidation of the genetic factors underlying chronic liver disease may reveal new therapeutic targets.

Methods: We used exome sequence data and electronic health records from 46,544 participants in the DiscovEHR human genetics study to identify genetic variants associated with serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Variants that were replicated in three additional cohorts (12,527 persons) were evaluated for association with clinical diagnoses of chronic liver disease in DiscovEHR study participants and two independent cohorts (total of 37,173 persons) and with histopathological severity of liver disease in 2391 human liver samples.

Results: A splice variant (rs72613567:TA) in HSD17B13, encoding the hepatic lipid droplet protein hydroxysteroid 17-beta dehydrogenase 13, was associated with reduced levels of ALT (P=4.2×10) and AST (P=6.2×10). Among DiscovEHR study participants, this variant was associated with a reduced risk of alcoholic liver disease (by 42% [95% confidence interval {CI}, 20 to 58] among heterozygotes and by 53% [95% CI, 3 to 77] among homozygotes), nonalcoholic liver disease (by 17% [95% CI, 8 to 25] among heterozygotes and by 30% [95% CI, 13 to 43] among homozygotes), alcoholic cirrhosis (by 42% [95% CI, 14 to 61] among heterozygotes and by 73% [95% CI, 15 to 91] among homozygotes), and nonalcoholic cirrhosis (by 26% [95% CI, 7 to 40] among heterozygotes and by 49% [95% CI, 15 to 69] among homozygotes). Associations were confirmed in two independent cohorts. The rs72613567:TA variant was associated with a reduced risk of nonalcoholic steatohepatitis, but not steatosis, in human liver samples. The rs72613567:TA variant mitigated liver injury associated with the risk-increasing PNPLA3 p.I148M allele and resulted in an unstable and truncated protein with reduced enzymatic activity.

Conclusions: A loss-of-function variant in HSD17B13 was associated with a reduced risk of chronic liver disease and of progression from steatosis to steatohepatitis. (Funded by Regeneron Pharmaceuticals and others.).
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http://dx.doi.org/10.1056/NEJMoa1712191DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6668033PMC
March 2018

Glucagon contributes to liver zonation.

Proc Natl Acad Sci U S A 2018 04 19;115(17):E4111-E4119. Epub 2018 Mar 19.

Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591

Liver zonation characterizes the separation of metabolic pathways along the lobules and is required for optimal function. Wnt/β-catenin signaling controls metabolic zonation by activating genes in the perivenous hepatocytes, while suppressing genes in the periportal counterparts. We now demonstrate that glucagon opposes the actions of Wnt/β-catenin signaling on gene expression and metabolic zonation pattern. The effects were more pronounced in the periportal hepatocytes where 28% of all genes were activated by glucagon and inhibited by Wnt/β-catenin. The glucagon and Wnt/β-catenin receptors and their signaling pathways are uniformly distributed in periportal and perivenous hepatocytes and the expression is not regulated by the opposing signal. Collectively, our results show that glucagon controls gene expression and metabolic zonation in the liver through a counterplay with the Wnt/β-catenin signaling pathway.
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http://dx.doi.org/10.1073/pnas.1721403115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5924920PMC
April 2018

Inositol hexakisphosphate kinase 1 is a metabolic sensor in pancreatic β-cells.

Cell Signal 2018 06 6;46:120-128. Epub 2018 Mar 6.

The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-171 76 Stockholm, Sweden; School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea. Electronic address:

Diphosphoinositol pentakisphosphate (IP) is critical for the exocytotic capacity of the pancreatic β-cell, but its regulation by the primary instigator of β-cell exocytosis, glucose, is unknown. The high K for ATP of the IP-generating enzymes, the inositol hexakisphosphate kinases (IP6K1 and 2) suggests that these enzymes might serve as metabolic sensors in insulin secreting β-cells and act as translators of disrupted metabolism in diabetes. We investigated this hypothesis and now show that glucose stimulation, which increases the ATP/ADP ratio, leads to an early rise in IP concentration in β-cells. RNAi mediated knock down of the IP6K1 isoform inhibits both glucose-mediated increase in IP and first phase insulin secretion, demonstrating that IP6K1 integrates glucose metabolism and insulin exocytosis. In diabetic mouse islets the deranged ATP/ADP levels under both basal and glucose-stimulated conditions are mirrored in both disrupted IP generation and insulin release. Thus the unique metabolic sensing properties of IP6K1 guarantees appropriate concentrations of IP and thereby both correct basal insulin secretion and intact first phase insulin release. In addition, our data suggest that a specific cell signaling defect, namely, inappropriate IP generation may be an essential convergence point integrating multiple metabolic defects into the commonly observed phenotype in diabetes.
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http://dx.doi.org/10.1016/j.cellsig.2018.03.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5899964PMC
June 2018

Increased thermogenesis by a noncanonical pathway in ANGPTL3/8-deficient mice.

Proc Natl Acad Sci U S A 2018 02 22;115(6):E1249-E1258. Epub 2018 Jan 22.

Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390;

Dietary triglyceride (TG) is the most efficient energy substrate. It is processed and stored at substantially lower metabolic cost than is protein or carbohydrate. In fed animals, circulating TGs are preferentially routed for storage to white adipose tissue (WAT) by angiopoietin-like proteins 3 (A3) and 8 (A8). Here, we show that mice lacking A3 and A8 ( mice) have decreased fat mass and a striking increase in temperature (+1 °C) in the fed (but not fasted) state, without alterations in food intake or physical activity. Subcutaneous WAT (WAT-SQ) from these animals had morphologic and metabolic changes characteristic of beiging. O consumption rates (OCRs) and expression of genes involved in both fatty acid synthesis and fatty acid oxidation were increased in WAT-SQ of mice, but not in their epididymal or brown adipose tissue (BAT). The hyperthermic response to feeding was blocked by maintaining mice at thermoneutrality or by treating with a β3-adrenergic receptor (AR) antagonist. To determine if sympathetic stimulation was sufficient to increase body temperature in mice, WT and animals were maintained at thermoneutrality and then treated with a β3-AR agonist; treatment induced hyperthermia in , but not WT, mice. Antibody-mediated inactivation of both circulating A3 and A8 induced hyperthermia in WT mice. Together, these data indicate that A3 and A8 are essential for efficient storage of dietary TG and that disruption of these genes increases feeding-induced thermogenesis and energy utilization.
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http://dx.doi.org/10.1073/pnas.1717420115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5819435PMC
February 2018

A first-in-human pharmacodynamic and pharmacokinetic study of a fully human anti-glucagon receptor monoclonal antibody in normal healthy volunteers.

Diabetes Obes Metab 2018 02 14;20(2):283-291. Epub 2017 Sep 14.

Regeneron Pharmaceuticals, Inc., Tarrytown, New York.

Aims: Glucagon receptor (GCGR) blockers are being investigated as potential therapeutics for type 1 and type 2 diabetes. Here we report the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of REGN1193, a fully human glucagon receptor blocking monoclonal antibody from a first-in-human healthy volunteer randomized double-blinded trial.

Methods: Healthy men and women received single ascending doses of REGN1193 ranging from 0.05 to 0.6 mg/kg (n = 42) or placebo (n = 14) intravenously. Safety, tolerability and PK were assessed over 106 days. The glucose-lowering effect of REGN1193 was assessed after induction of hyperglycaemia by serial glucagon challenges.

Results: REGN1193 was generally well tolerated. There were small (<3× the upper limit of normal) and transient dose-dependent increases in hepatic aminotransferases. No increase in LDL-C was observed. Hypoglycaemia, assessed as laboratory blood glucose ≤70 mg/dL, occurred in 6/14 (43%) subjects on placebo and 27/42 (57%) on REGN1193 across all dose groups. All episodes of hypoglycaemia were asymptomatic, >50 mg/dL, and did not require treatment or medical assistance. Concentration-time profiles suggest a 2-compartment disposition and marked nonlinearity, consistent with target-mediated clearance. REGN1193 inhibited the glucagon-stimulated glucose increase in a dose-dependent manner. The 0.6 mg/kg dose inhibited the glucagon-induced glucose area under the curve for 0 to 90 minutes (AUC ) by 80% to 90% on days 3 and 15, while blunting the increase in C-peptide. REGN1193 dose-dependently increased total GLP-1, GLP-2 and glucagon, with plasma levels returning to baseline by day 29 in all dose groups.

Conclusion: REGN1193, a GCGR-blocking monoclonal antibody, produced a safety, tolerability and PK/PD profile suitable for further clinical development. The occurrence of transient elevations in serum hepatic aminotransferases observed here and reported with several small molecule glucagon receptor antagonists suggests an on-target effect of glucagon receptor blockade. The underlying mechanism is unknown.
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http://dx.doi.org/10.1111/dom.13075DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5813272PMC
February 2018

Inflammatory Ly6Chi monocytes and their conversion to M2 macrophages drive atherosclerosis regression.

J Clin Invest 2017 Aug 26;127(8):2904-2915. Epub 2017 Jun 26.

Departments of Medicine (Cardiology) and Cell Biology, and the Marc and Ruti Bell Program in Vascular Biology, New York University School of Medicine, New York, New York, USA.

Atherosclerosis is a chronic inflammatory disease, and developing therapies to promote its regression is an important clinical goal. We previously established that atherosclerosis regression is characterized by an overall decrease in plaque macrophages and enrichment in markers of alternatively activated M2 macrophages. We have now investigated the origin and functional requirement for M2 macrophages in regression in normolipidemic mice that received transplants of atherosclerotic aortic segments. We compared plaque regression in WT normolipidemic recipients and those deficient in chemokine receptors necessary to recruit inflammatory Ly6Chi (Ccr2-/- or Cx3cr1-/-) or patrolling Ly6Clo (Ccr5-/-) monocytes. Atherosclerotic plaques transplanted into WT or Ccr5-/- recipients showed reduced macrophage content and increased M2 markers consistent with plaque regression, whereas plaques transplanted into Ccr2-/- or Cx3cr1-/- recipients lacked this regression signature. The requirement of recipient Ly6Chi monocyte recruitment was confirmed in cell trafficking studies. Fate-mapping and single-cell RNA sequencing studies also showed that M2-like macrophages were derived from newly recruited monocytes. Furthermore, we used recipient mice deficient in STAT6 to demonstrate a requirement for this critical component of M2 polarization in atherosclerosis regression. Collectively, these results suggest that continued recruitment of Ly6Chi inflammatory monocytes and their STAT6-dependent polarization to the M2 state are required for resolution of atherosclerotic inflammation and plaque regression.
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http://dx.doi.org/10.1172/JCI75005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5531402PMC
August 2017

Inhibition of PCSK9 does not improve lipopolysaccharide-induced mortality in mice.

J Lipid Res 2017 08 9;58(8):1661-1669. Epub 2017 Jun 9.

Departments of Internal Medicine and Molecular Genetics University of Texas Southwestern Medical Center, Dallas, TX

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein that targets LDL receptors (LDLRs) for degradation in liver. Blocking the interaction of PCSK9 with the LDLR potently reduces plasma LDL cholesterol levels and cardiovascular events. Recently, it has been suggested that inhibition of PCSK9 might also improve outcomes in mice and humans with sepsis, possibly by increasing LDLR-mediated clearance of endotoxins. Sepsis is a complication of a severe microbial infection that has shared pathways with lipid metabolism. Here, we tested whether anti-PCSK9 antibodies prevent death from lipopolysaccharide (LPS)-induced endotoxemia. Mice were administered PCSK9 antibodies prior to, or shortly after, injecting LPS. In both scenarios, the administration of PCSK9 antibodies did not alter endotoxemia-induced mortality. Afterward, we determined whether the complete absence of PCSK9 improved endotoxemia-induced mortality in mice with the germ-line deletion of Similarly, PCSK9 knockout mice were not protected from LPS-induced death. To determine whether low LDLR expression increased LPS-induced mortality, mice and PCSK9 transgenic mice were studied after injection of LPS. Endotoxemia-induced mortality was not altered in either mouse model. In a human cohort, we observed no correlation between plasma inflammation markers with total cholesterol levels, LDL cholesterol, and PCSK9. Combined, our data demonstrate that PCSK9 inhibition provides no protection from LPS-induced mortality in mice.
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http://dx.doi.org/10.1194/jlr.M076844DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5538287PMC
August 2017

Amino Acid Transporter Slc38a5 Controls Glucagon Receptor Inhibition-Induced Pancreatic α Cell Hyperplasia in Mice.

Cell Metab 2017 Jun;25(6):1348-1361.e8

Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591, USA. Electronic address:

Glucagon supports glucose homeostasis by stimulating hepatic gluconeogenesis, in part by promoting the uptake and conversion of amino acids into gluconeogenic precursors. Genetic disruption or pharmacologic inhibition of glucagon signaling results in elevated plasma amino acids and compensatory glucagon hypersecretion involving expansion of pancreatic α cell mass. Recent findings indicate that hyperaminoacidemia triggers pancreatic α cell proliferation via an mTOR-dependent pathway. We confirm and extend these findings by demonstrating that glucagon pathway blockade selectively increases expression of the sodium-coupled neutral amino acid transporter Slc38a5 in a subset of highly proliferative α cells and that Slc38a5 controls the pancreatic response to glucagon pathway blockade; most notably, mice deficient in Slc38a5 exhibit markedly decreased α cell hyperplasia to glucagon pathway blockade-induced hyperaminoacidemia. These results show that Slc38a5 is a key component of the feedback circuit between glucagon receptor signaling in the liver and amino-acid-dependent regulation of pancreatic α cell mass in mice.
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http://dx.doi.org/10.1016/j.cmet.2017.05.006DOI Listing
June 2017

Genetic and Pharmacologic Inactivation of ANGPTL3 and Cardiovascular Disease.

N Engl J Med 2017 07 24;377(3):211-221. Epub 2017 May 24.

From Regeneron Genetics Center (F.E.D., C.O., C.S., O.G., S.M., C.V.V.H., S.B., L.H., A.L., J.P., N.S., A.J.M., J.D.O., J.G.R., A.R.S., I.B.B., T.M.T., G.D.Y., S.J.M., A. Baras) and Regeneron Pharmaceuticals (V.G., H.M.D., A.Z., W.S., N.S., A.J.M., S.H., A. Bouzelmat, R.Z., B.S., R.P., D.G., G.A.H., W.J.S., P.B., G.D.Y., S.J.M., J.G.) Tarrytown, NY; the Department of Medicine, Division of Translational Medicine and Human Genetics (R.L.D.), and Departments of Surgery (S.D.) and Genetics and Medicine (A.S., D.J.R.), Perelman School of Medicine, University of Pennsylvania, Philadelphia, and Geisinger Health System, Danville (J.B.L., M.F.M., M.D.R., H.L.K., D.H.L., D.J.C.) - both in Pennsylvania; the Division of Endocrinology and Metabolism, Department of Internal Medicine (W.H.H.S., I.-T.L.) and Cardiovascular Center (K.-W.L.), Taichung Veterans General Hospital, Institute of Medical Technology, National Chung-Hsing University (W.H.H.S.), School of Medicine, Chung Shan Medical University (I.-T.L.), and the Department of Medicine, China Medical University (K.-W.L.), Taichung, and School of Medicine, National Yang-Ming University (W.H.H.S., I.-T.L., K.-W.L.), and School of Medicine, National Defense Medical Center (W.H.H.S.), Taipei - all in Taiwan; Institute for Translational Genomics and Population Sciences, Los Angeles Biomedical Research Institute and Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA (X.G., J.I.R., Y.-D.I.C.); the Division of Cardiology, Department of Medicine, Molecular Physiology Institute, School of Medicine, Duke University, Durham, NC (W.E.K., S.H.S.); the Department of Clinical Biochemistry, Rigshospitalet (A.B.W., B.G.N., A.T.-H.), the Copenhagen General Population Study (B.G.N., A.T.-H.) and Department of Clinical Biochemistry (B.G.N.), Herlev and Gentofte Hospital, and the Copenhagen City Heart Study, Frederiksberg Hospital, Copenhagen University Hospital, and Faculty of Health and Medical Sciences, University of Copenhagen (B.G.N., A.T.-H.) - all in Copenhagen; and TNO Metabolic Health Research, Gaubius Laboratory, Leiden, the Netherlands (A.M.H., H.M.G.P.).

Background: Loss-of-function variants in the angiopoietin-like 3 gene (ANGPTL3) have been associated with decreased plasma levels of triglycerides, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol. It is not known whether such variants or therapeutic antagonism of ANGPTL3 are associated with a reduced risk of atherosclerotic cardiovascular disease.

Methods: We sequenced the exons of ANGPTL3 in 58,335 participants in the DiscovEHR human genetics study. We performed tests of association for loss-of-function variants in ANGPTL3 with lipid levels and with coronary artery disease in 13,102 case patients and 40,430 controls from the DiscovEHR study, with follow-up studies involving 23,317 case patients and 107,166 controls from four population studies. We also tested the effects of a human monoclonal antibody, evinacumab, against Angptl3 in dyslipidemic mice and against ANGPTL3 in healthy human volunteers with elevated levels of triglycerides or LDL cholesterol.

Results: In the DiscovEHR study, participants with heterozygous loss-of-function variants in ANGPTL3 had significantly lower serum levels of triglycerides, HDL cholesterol, and LDL cholesterol than participants without these variants. Loss-of-function variants were found in 0.33% of case patients with coronary artery disease and in 0.45% of controls (adjusted odds ratio, 0.59; 95% confidence interval, 0.41 to 0.85; P=0.004). These results were confirmed in the follow-up studies. In dyslipidemic mice, inhibition of Angptl3 with evinacumab resulted in a greater decrease in atherosclerotic lesion area and necrotic content than a control antibody. In humans, evinacumab caused a dose-dependent placebo-adjusted reduction in fasting triglyceride levels of up to 76% and LDL cholesterol levels of up to 23%.

Conclusions: Genetic and therapeutic antagonism of ANGPTL3 in humans and of Angptl3 in mice was associated with decreased levels of all three major lipid fractions and decreased odds of atherosclerotic cardiovascular disease. (Funded by Regeneron Pharmaceuticals and others; ClinicalTrials.gov number, NCT01749878 .).
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http://dx.doi.org/10.1056/NEJMoa1612790DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5800308PMC
July 2017