Endocrinology
Abstract
Offspring of women with gestational diabetes mellitus (GDM) are at increased risk of developing metabolic disease, potentially mediated by epigenetic mechanisms. We recruited 608 GDM and 626 control offspring from the Danish National Birth Cohort, aged between 9 and 16 years. DNA methylation profiles were measured in peripheral blood of 93 GDM offspring and 95 controls using the Illumina HumanMethylation450 BeadChip. Pyrosequencing was performed for validation/replication of putative GDM-associated, differentially methylated CpGs in additional 905 offspring (462 GDM, 444 control offspring). We identified 76 differentially methylated CpGs in GDM offspring compared with controls in the discovery cohort (FDR, P < 0.05). Adjusting for offspring BMI did not affect the association between methylation levels and GDM status for any of the 76 CpGs. Most of these epigenetic changes were due to confounding by maternal prepregnancy BMI; however, 13 methylation changes were independently associated with maternal GDM. Three prepregnancy BMI–associated CpGs (cg00992687 and cg09452568 of ESM1 and cg14328641 of MS4A3) were validated in the replication cohort, while cg09109411 (PDE6A) was found to be associated with GDM status. The identified methylation changes may reflect developmental programming of organ disease mechanisms and/or may serve as disease biomarkers.
Authors
Line Hjort, David Martino, Louise Groth Grunnet, Haroon Naeem, Jovana Maksimovic, Anders Henrik Olsson, Cuilin Zhang, Charlotte Ling, Sjurdur Frodi Olsen, Richard Saffery, Allan Arthur Vaag
Abstract
Metastatic medullary thyroid cancer (MTC) is incurable and FDA-approved kinase inhibitors that include oncogenic RET as a target do not result in complete responses. Association studies of human MTCs and murine models suggest that the CDK/RB pathway may be an alternative target. The objective of this study was to determine if CDKs represent therapeutic targets for MTC and to define mechanisms of activity. Using human MTC cells that are either sensitive or resistant to vandetanib, we demonstrate that palbociclib (CDK4/6 inhibitor) is not cytotoxic to MTC cells but that they are highly sensitive to dinaciclib (CDK1/2/5/9 inhibitor) accompanied by reduced CDK9 and RET protein and mRNA levels. CDK9 protein was highly expressed in 83 of 83 human MTCs and array–comparative genomic hybridization had copy number gain in 11 of 30 tumors. RNA sequencing demonstrated that RNA polymerase II–dependent transcription was markedly reduced by dinaciclib. The CDK7 inhibitor THZ1 also demonstrated high potency and reduced RET and CDK9 levels. ChIP-sequencing using H3K27Ac antibody identified a superenhancer in intron 1 of RET. Finally, combined inhibition of dinaciclib with a RET kinase inhibitor was synergistic. In summary, we have identified what we believe is a novel mechanism of RET transcription regulation that potentially can be exploited to improve RET therapeutic targeting.
Authors
Anisley Valenciaga, Motoyasu Saji, Lianbo Yu, Xiaoli Zhang, Ceimoani Bumrah, Ayse S. Yilmaz, Christina M. Knippler, Wayne Miles, Thomas J. Giordano, Gilbert J. Cote, Matthew D. Ringel
Abstract
Although the cause of hypertension among individuals with obesity and insulin resistance is unknown, increased plasma insulin, acting in the kidney to increase sodium reabsorption, has been proposed as a potential mechanism. Insulin may also stimulate glucose uptake, but the contributions of tubular insulin signaling to sodium or glucose transport in the setting of insulin resistance is unknown. To directly study the role of insulin signaling in the kidney, we generated inducible renal tubule–specific insulin receptor–KO mice and used high-fat feeding and mineralocorticoids to model obesity and insulin resistance. Insulin receptor deletion did not alter blood pressure or sodium excretion in mice on a high-fat diet alone, but it mildly attenuated the increase in blood pressure with mineralocorticoid supplementation. Under these conditions, KO mice developed profound glucosuria. Insulin receptor deletion significantly reduced SGLT2 expression and increased urinary glucose excretion and urine flow. These data demonstrate a direct role for insulin receptor–stimulated sodium and glucose transport and a functional interaction of insulin signaling with mineralocorticoids in vivo. These studies uncover a potential mechanistic link between preserved insulin sensitivity and renal glucose handling in obesity and insulin resistance.
Authors
Jonathan M. Nizar, Blythe D. Shepard, Vianna T. Vo, Vivek Bhalla
Abstract
The human adaptive starvation response allows for survival during long-term caloric deprivation. Whether the physiology of starvation is adaptive or maladaptive is context dependent: activation of pathways by caloric restriction may promote longevity, yet in the context of caloric excess, the same pathways may contribute to obesity. Here, we performed plasma metabolite profiling of longitudinally collected samples during a 10-day, 0-calorie fast in humans. We identify classical milestones in adaptive starvation, including the early consumption of gluconeogenic amino acids and the subsequent surge in plasma nonesterified fatty acids that marks the shift from carbohydrate to lipid metabolism, and demonstrate findings, including (a) the preferential release of unsaturated fatty acids and an associated shift in plasma lipid species with high degrees of unsaturation and (b) evidence that acute, starvation-mediated hypoleptinemia may be a driver of the transition from glucose to lipid metabolism in humans.
Authors
Matthew L. Steinhauser, Benjamin A. Olenchock, John O’Keefe, Mingyue Lun, Kerry A. Pierce, Hang Lee, Lorena Pantano, Anne Klibanski, Gerald I. Shulman, Clary B. Clish, Pouneh K. Fazeli
Abstract
BACKGROUND. The duration and patterns of β cell dysfunction during type 1 diabetes (T1D) development have not been fully defined. METHODS. Metabolic measures derived from oral glucose tolerance tests (OGTTs) were compared between autoantibody-positive (aAb+) individuals followed in the TrialNet Pathway to Prevention study who developed diabetes after 5 or more years or less than 5 years of longitudinal follow-up (Progressors≥5, n = 75; Progressors<5, n = 474) and 144 aAb-negative (aAb–) relatives. RESULTS. Mean age at study entry was 15.0 ± 12.6 years for Progressors≥5; 12.0 ± 9.1 for Progressors<5; and 16.3 ± 10.4 for aAb– relatives. At baseline, Progressors≥5 already exhibited significantly lower fasting C-peptide (P < 0.01), C-peptide AUC (P < 0.001), and early C-peptide responses (30- to 0-minute C-peptide; P < 0.001) compared with aAb– relatives, while 2-hour glucose (P = 0.03), glucose AUC (<0.001), and Index60 (<0.001) were all higher. Despite significant baseline impairment, metabolic measures in Progressors≥5 were relatively stable until 2 years prior to T1D diagnosis, when there was accelerated C-peptide decline and rising glycemia from 2 years until diabetes diagnosis. Remarkably, patterns of progression within 3 years of diagnosis were nearly identical between Progressors≥5 and Progressors<5. CONCLUSION. These data provide insight into the chronicity of β cell dysfunction in T1D and indicate that β cell dysfunction may precede diabetes diagnosis by more than 5 years in a subset of aAb+ individuals. Even among individuals with varying lengths of aAb positivity, our findings indicate that patterns of metabolic decline are uniform within the last 3 years of progression to T1D. TRIAL REGISTRATION. Clinicaltrials.gov NCT00097292. FUNDING. The Type 1 Diabetes TrialNet Study Group is a clinical trials network currently funded by the NIH through the National Institute of Diabetes and Digestive and Kidney Diseases, the National Institute of Allergy and Infectious Diseases, and The Eunice Kennedy Shriver National Institute of Child Health and Human Development and the Juvenile Diabetes Research Foundation.
Authors
Carmella Evans-Molina, Emily K. Sims, Linda A. DiMeglio, Heba M. Ismail, Andrea K. Steck, Jerry P. Palmer, Jeffrey P. Krischer, Susan Geyer, Ping Xu, Jay M. Sosenko, the Type 1 Diabetes TrialNet Study Group
Abstract
BACKGROUND. Exercise has profound pleiotropic health benefits, yet the underlying mechanisms remain incompletely understood. Endocrine FGF21, bile acids (BAs), and BA-induced FGF19 have emerged as metabolic signaling molecules. Here, we investigated if dissimilar modes of exercise, resistance exercise (RE) and endurance exercise (EE), regulate plasma BAs, FGF19, and FGF21 in humans. METHODS. Ten healthy, moderately trained males were enrolled in a randomized crossover study of 1 hour of bicycling at 70% of VO2peak (EE) and 1 hour of high-volume RE. Hormones and metabolites were measured in venous blood and sampled before and after exercise and at 15, 30, 60, 90, 120, and 180 minutes after exercise. RESULTS. We observed exercise mode–specific changes in plasma concentrations of FGF19 and FGF21. Whereas FGF19 decreased following RE (P < 0.001), FGF21 increased in response to EE (P < 0.001). Total plasma BAs decreased exclusively following RE (P < 0.05), but the composition of BAs changed in response to both types of exercise. Notably, circulating levels of the potent TGR5 receptor agonist, lithocholic acid, increased with both types of exercise (P < 0.001). CONCLUSION. This study reveals divergent effects of EE and RE on circulating concentrations of the BA species, FGF19, and FGF21. We identify temporal relationships between decreased BA and FGF19 following RE and a sharp disparity in FGF21 concentrations, with EE eliciting a clear increase parallel to that of glucagon. FUNDING. The Novo Nordisk Foundation (NNF17OC0026114) and the Lundbeck Foundation (R238-2016-2859).
Authors
Thomas Morville, Ronni E. Sahl, Samuel A.J. Trammell, Jens S. Svenningsen, Matthew P. Gillum, Jørn W. Helge, Christoffer Clemmensen
Abstract
Aldosterone synthase inhibitors (ASIs) should alleviate obesity-related cardiovascular and renal problems resulting partly from aldosterone excess, but their clinical use may have limitations. To improve knowledge for the use of ASIs, we investigated physiology in aldosterone synthase–knockout (ASKO) mice. On regular chow diet (CD), ASKO mice ate more and weighed less than WT mice, largely because they hyperventilated to eliminate acid as CO2. Replacing CD with high-fat diet (HFD) lessened the respiratory burden in ASKO mice, as did 12- to 15-hour fasting. The latter eliminated the genotype differences in respiratory workload and energy expenditure (EE). Thus, aldosterone deficiency burdened the organism more when the animals ate carbohydrate-rich chow than when they ate a HFD. Chronic HFD exposure further promoted hyperinsulinemia in ASKO mice that contributed to visceral fat accumulation accompanied by reduced lipolysis, thermogenic reprogramming, and the absence of weight-gain-related EE increases. Intracerebroventricular aldosterone supplementation in ASKO mice attenuated the HFD-induced hyperinsulinemia, but did not affect EE, suggesting that the presence of aldosterone increased the body’s energetic efficiency, thus counteracting the EE-increasing effect of low insulin. ASIs may therefore cause acid-overload-induced respiratory burden and promote obesity. Their use in patients with preexisting renal and cardiopulmonary diseases might be contraindicated.
Authors
Wan-Hui Liao, Claudia Suendermann, Andrea Eva Steuer, Gustavo Pacheco Lopez, Alex Odermatt, Nourdine Faresse, Maciej Henneberg, Wolfgang Langhans
Abstract
Obesity increases breast cancer mortality by promoting resistance to therapy. Here, we identified regulatory pathways in estrogen receptor–positive (ER-positive) tumors that were shared between patients with obesity and those with resistance to neoadjuvant aromatase inhibition. Among these was fibroblast growth factor receptor 1 (FGFR1), a known mediator of endocrine therapy resistance. In a preclinical model with patient-derived ER-positive tumors, diet-induced obesity promoted a similar gene expression signature and sustained the growth of FGFR1-overexpressing tumors after estrogen deprivation. Tumor FGFR1 phosphorylation was elevated with obesity and predicted a shorter disease-free and disease-specific survival for patients treated with tamoxifen. In both human and mouse mammary adipose tissue, FGF1 ligand expression was associated with metabolic dysfunction, weight gain, and adipocyte hypertrophy, implicating the impaired response to a positive energy balance in growth factor production within the tumor niche. In conjunction with these studies, we describe a potentially novel graft-competent model that can be used with patient-derived tissue to elucidate factors specific to extrinsic (host) and intrinsic (tumor) tissue that are critical for obesity-associated tumor promotion. Taken together, we demonstrate that obesity and excess energy establish a tumor environment with features of endocrine therapy resistance and identify a role for ligand-dependent FGFR1 signaling in obesity-associated breast cancer progression.
Authors
Elizabeth A. Wellberg, Peter Kabos, Austin E. Gillen, Britta M. Jacobsen, Heather M. Brechbuhl, Stevi J. Johnson, Michael C. Rudolph, Susan M. Edgerton, Ann D. Thor, Steven M. Anderson, Anthony Elias, Xi Kathy Zhou, Neil M. Iyengar, Monica Morrow, Domenick J. Falcone, Omar El-Hely, Andrew J. Dannenberg, Carol A. Sartorius, Paul S. MacLean
Abstract
BACKGROUND. The prevalence of chronic kidney disease (CKD) is increasing worldwide. The identification of factors contributing to its progression is important for designing preventive measures. Previous studies have suggested that chronically high vasopressin is deleterious to renal function. Here, we evaluated the association of plasma copeptin, a surrogate of vasopressin, with the incidence of CKD in the general population. METHODS. We studied 3 European cohorts: DESIR (n = 5,047; France), MDCS-CC (n = 3,643; Sweden), and PREVEND (n = 7,684; the Netherlands). Median follow-up was 8.5, 16.5, and 11.3 years, respectively. Pooled data were analyzed at an individual level for 4 endpoints during follow-up: incidence of stage 3 CKD (estimated glomerular filtration rate [eGFR] < 60 ml/min/1.73 m2); the KDIGO criterion “certain drop in eGFR”; rapid kidney function decline (eGFR slope steeper than –3 ml/min/1.73 m2/yr); and incidence of microalbuminuria. RESULTS. The upper tertile of plasma copeptin was significantly and independently associated with a 49% higher risk for stage 3 CKD (P < 0.0001); a 64% higher risk for kidney function decline, as defined by the KDIGO criterion (P < 0.0001); a 79% higher risk for rapid kidney function decline (P < 0.0001); and a 24% higher risk for microalbuminuria (P = 0.008). CONCLUSIONS. High copeptin levels are associated with the development and the progression of CKD in the general population. Intervention studies are needed to assess the potential beneficial effect on kidney health in the general population of reducing vasopressin secretion or action. FUNDING. INSERM and Danone Research Centre for Specialized Nutrition.
Authors
Ray El Boustany, Irina Tasevska, Esther Meijer, Lyanne M. Kieneker, Sofia Enhörning, Guillaume Lefèvre, Kamel Mohammedi, Michel Marre, Frédéric Fumeron, Beverley Balkau, Nadine Bouby, Lise Bankir, Stephan J.L. Bakker, Ronan Roussel, Olle Melander, Ron T. Gansevoort, Gilberto Velho
Abstract
Androgen excess predisposes women to type 2 diabetes (T2D), but the mechanism of this is poorly understood. We report that female mice fed a Western diet and exposed to chronic androgen excess using dihydrotestosterone (DHT) exhibit hyperinsulinemia and insulin resistance associated with secondary pancreatic β cell failure, leading to hyperglycemia. These abnormalities are not observed in mice lacking the androgen receptor (AR) in β cells and partially in neurons of the mediobasal hypothalamus (MBH) as well as in mice lacking AR selectively in neurons. Accordingly, i.c.v. infusion of DHT produces hyperinsulinemia and insulin resistance in female WT mice. We observe that acute DHT produces insulin hypersecretion in response to glucose in cultured female mouse and human pancreatic islets in an AR-dependent manner via a cAMP- and mTOR-dependent pathway. Acute DHT exposure increases mitochondrial respiration and oxygen consumption in female cultured islets. As a result, chronic DHT exposure in vivo promotes islet oxidative damage and susceptibility to additional stress induced by streptozotocin via AR in β cells. This study suggests that excess androgen predisposes female mice to T2D following AR activation in neurons, producing peripheral insulin resistance, and in pancreatic β cells, promoting insulin hypersecretion, oxidative injury, and secondary β cell failure.
Authors
Guadalupe Navarro, Camille Allard, Jamie J. Morford, Weiwei Xu, Suhuan Liu, Adrien J.R. Molinas, Sierra M. Butcher, Nicholas H.F. Fine, Manuel Blandino-Rosano, Venkata N. Sure, Sangho Yu, Rui Zhang, Heike Münzberg, David A. Jacobson, Prasad V. Katakam, David J. Hodson, Ernesto Bernal-Mizrachi, Andrea Zsombok, Franck Mauvais-Jarvis
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