Ring Finger Protein 11 Inhibits Melanocortin 3 and 4 Receptor Signaling

Intact melanocortin signaling via the G protein-coupled receptors (GPCRs), melanocortin receptor 4 (MC4R), and melanocortin receptor 3 (MC3R) is crucial for body weight maintenance. So far, no connection between melanocortin signaling and hypothalamic inflammation has been reported. Using a bimolecular fluorescence complementation library screen, we identified a new interaction partner for these receptors, ring finger protein 11 (RNF11). RNF11 participates in the constitution of the A20 complex that is involved in reduction of tumor necrosis factor α (TNFα)-induced NFκB signaling, an important pathway in hypothalamic inflammation. Mice treated with high-fat diet (HFD) for 3 days demonstrated a trend toward an increase in hypothalamic Rnf11 expression, as shown for other inflammatory markers under HFD. Furthermore, Gs-mediated signaling of MC3/4R was demonstrated to be strongly reduced to 20–40% by co-expression of RNF11 despite unchanged total receptor expression. Cell surface expression was not affected for MC3R but resulted in a significant reduction of MC4R to 61% by co-expression with RNF11. Mechanisms linking HFD, inflammation, and metabolism remain partially understood. In this study, a new axis between signaling of specific body weight regulating GPCRs and factors involved in hypothalamic inflammation is suggested

Human gestational N‐methyl‐d‐aspartate receptor autoantibodies impair neonatal murine brain function

Objective: Maternal autoantibodies are a risk factor for impaired brain development in offspring. Antibodies (ABs) against the NR1 (GluN1) subunit of the N-methyl-d-aspartate receptor (NMDAR) are among the most frequently diagnosed anti-neuronal surface ABs, yet little is known about effects on fetal development during pregnancy. Methods: We established a murine model of in utero exposure to human recombinant NR1 and isotype-matched nonreactive control ABs. Pregnant C57BL/6J mice were intraperitoneally injected on embryonic days 13 and 17 each with 240μg of human monoclonal ABs. Offspring were investigated for acute and chronic effects on NMDAR function, brain development, and behavior. Results: Transferred NR1 ABs enriched in the fetus and bound to synaptic structures in the fetal brain. Density of NMDAR was considerably reduced (up to -49.2%) and electrophysiological properties were altered, reflected by decreased amplitudes of spontaneous excitatory postsynaptic currents in young neonates (-34.4%). NR1 AB-treated animals displayed increased early postnatal mortality (+27.2%), impaired neurodevelopmental reflexes, altered blood pH, and reduced bodyweight. During adolescence and adulthood, animals showed hyperactivity (+27.8% median activity over 14 days), lower anxiety, and impaired sensorimotor gating. NR1 ABs caused long-lasting neuropathological effects also in aged mice (10 months), such as reduced volumes of cerebellum, midbrain, and brainstem. Interpretation: The data collectively support a model in which asymptomatic mothers can harbor low-level pathogenic human NR1 ABs that are diaplacentally transferred, causing neurotoxic effects on neonatal development. Thus, AB-mediated network changes may represent a potentially treatable neurodevelopmental congenital brain disorder contributing to lifelong neuropsychiatric morbidity in affected children

Untersuchung zur transkriptionellen Regulation des Angiopoietin-2 in humanen Endothelzellen

Angiopoietin-2 (Ang-2) wirkt gefäßdestabilisierend und ist Voraussetzung für das Aussprossen von Gefäßen am Anfang der angiogenen Kaskade. Die Expression des Antagonisten der endothelialen Rezeptor-Tyrosin-Kinase Tie-2 ist streng gewebsspezifisch reguliert. Trotz des Zusammenhangs von Ang-2 und pathologischer Angiogenese sind die molekularen Mechanismen der ang-2 Regulation noch unverstanden. Mittels Microarray wurden die genomweiten Expressionsänderungen in endothelialen Zellen nach Behandlung mit dem demethylierenden 5-Aza-2’-deoxycytidine (5-Aza-dC) untersucht. Unter den induzierten Genen wurde ang-2 mit dem Fokus auf angiogeneserelevante Gene identifiziert. Obwohl die Endothelzellen unter Kontrollbedingungen ang-2 exprimieren, wurde die Expression durch Demethylierung weiter gesteigert. Es wurden jedoch keine potentiellen CpG-Inseln in unmittelbarer Nähe des Transkriptionsstarts identifiziert. Diese Daten lassen auf einen methylierungsunabhängigen Effekt von 5-Aza-dC auf die ang-2 Expression schließen. Zur molekularen Untersuchung der ang-2 Expression wurden 3kb der 5´-flankierenden Sequenz des humanen ang-2 Gens kloniert und der Transkriptionsstartpunkt (TS) bestimmt. Durch funktionelle 5´-Deletionsanalyse und zielgerichtete Mutagenese wurden regulatorische Promotorelemente identifiziert. Die Promotorregion -105 bis +51 relativ zum TS war ausreichend für die Vermittlung der basalen ang-2 Expression. Mittels Bindungsstudien wurden die Transkriptionsfaktoren Sp1 und Sp3 als Proteine, die primär an den ang-2 Minimalpromotor binden, identifiziert. Die Basen -78 bis -74 relativ zum TS sind eine essentielle Sp-Bindestelle für die Regulation der ang-2 Expression. Durch Mutation von potentiellen Bindungsstellen für Proteine der ETS-Familie wurde die ang-2 Promotoraktivität signifikant reduziert. Jedoch konnte die Spezifität von ETS-Proteinen in Bindungsstudien nicht bestätigt werden. Die Ergebnisse dieser Arbeit haben neue Einblicke in die ang-2 Regulation offenbart und zeigen, dass die Sp1/Sp3-abhängige Aktivierung des proximalen Promotorbereichs (-105/-56) entscheidend für die transkriptionelle ang-2 Regulation in Endothelzellen ist.Angiopoitein-2 (Ang-2) acts destabilizing on blood vessels and is mandatory for the onset of the angiogenic cascade. The expression of the antagonistic ligand of the endothelial cell tyrosine kinase receptor Tie-2 is tightly regulated. Despite the accumulating evidence confirming the involvement of Ang-2 in pathologic angiogenesis, the molecular mechanisms controlling ang-2 expression are still unclear. Using microarray analysis, the global changes of gene expression were investigated after treatment of endothelial cells with the demethylating agent 5-aza-2’-deoxycytidine (5-aza-dC). Focusing on angiogenesis related genes, ang-2 was identified among the upregulated ones. Although endothelial cells expressed ang-2 under control conditions already the expression was further increased by drug-induced demethylation. A screen for CpG-islands revealed no putative islands surrounding the transcription initiation site. These data indicate a methylation-independent effect of 5-aza-dC on the ang-2 expression. To elucidate underlying molecular mechanisms of ang-2 expression, 3kb of the human ang-2 gene were cloned and the transcription start site (TS) determined. Regulatory promoter elements were identified by functional 5’-deletion analysis and site-directed mutagenesis. The promoter region -105 to +51 relative to TS was recognized as sufficient and necessary for the ang-2 gene transcription. Electrophoretic Mobility Shift Assays revealed Sp1 and Sp3 as dominant nuclear proteins binding to the ang-2 promoter. The region spanning -78/-74 was identified as essential Sp1/3 site regulating ang-2 expression. The mutation of potential ETS-binding sites resulted in a significant decrease of ang-2 promoter activity. However, the binding of ETS-proteins could not be confirmed by means of EMSA. The results of this thesis revealed new insights of ang-2 regulation and strongly suggest that Sp1/Sp3-dependent activation of an upstream enhancer at -105 to -56 is crucial for the regulation of ang-2 expression in endothelial cells

Genetic and epigenetic factors determining NAFLD risk

BACKGROUND: Hepatic steatosis is a common chronic liver disease that can progress into more severe stages of NAFLD or promote the development of life-threatening secondary diseases for some of those affected. These include the liver itself (nonalcoholic steatohepatitis or NASH; fibrosis and cirrhosis, and hepatocellular carcinoma) or other organs such as the vessels and the heart (cardiovascular disease) or the islets of Langerhans (type 2 diabetes). In addition to elevated caloric intake and a sedentary lifestyle, genetic and epigenetic predisposition contribute to the development of NAFLD and the secondary diseases. SCOPE OF REVIEW: We present data from genome-wide association studies (GWAS) and functional studies in rodents which describe polymorphisms identified in genes relevant for the disease as well as changes caused by altered DNA methylation and gene regulation via specific miRNAs. The review also provides information on the current status of the use of genetic and epigenetic factors as risk markers. MAJOR CONCLUSION: With our overview we provide an insight into the genetic and epigenetic landscape of NAFLD and argue about the applicability of currently defined risk scores for risk stratification and conclude that further efforts are needed to make the scores more usable and meaningful

Alterations of Lipid Profile in Livers with Impaired Lipophagy

Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation in the liver. Various mechanisms such as an increased uptake in fatty acids or de novo synthesis contribute to the development of steatosis and progression to more severe stages. Furthermore, it has been shown that impaired lipophagy, the degradation of lipids by autophagic processes, contributes to NAFLD. Through an unbiased lipidome analysis of mouse livers in a genetic model of impaired lipophagy, we aimed to determine the resulting alterations in the lipidome. Observed changes overlap with those of the human disease. Overall, the entire lipid content and in particular the triacylglycerol concentration increased under conditions of impaired lipophagy. In addition, we detected a reduction in long-chain polyunsaturated fatty acids (PUFAs) and an increased ratio of n-6 PUFAs to n-3 PUFAs, which was due to the depletion of n-3 PUFAs. Although the abundance of major phospholipid classes was reduced, the ratio of phosphatidylcholines to phosphatidylethanolamines was not affected. In conclusion, this study demonstrates that impaired lipophagy contributes to the pathology of NAFLD and is associated with an altered lipid profile. However, the lipid pattern does not appear to be specific for lipophagic alterations, as it resembles mainly that described in relation to fatty liver disease

Gut microbiota and glucometabolic alterations in response to recurrent partial sleep deprivation in normal-weight young individuals

Objective: Changes to the microbial community in the human gut have been proposed to promote metabolic disturbances that also occur after short periods of sleep loss (including insulin resistance). However, whether sleep loss affects the gut microbiota remains unknown. Methods: In a randomized within-subject crossover study utilizing a standardized in-lab protocol (with fixed meal times and exercise schedules), we studied nine normal-weight men at two occasions: after two nights of partial sleep deprivation (PSD; sleep opportunity 02:45–07:00 h), and after two nights of normal sleep (NS; sleep opportunity 22:30–07:00 h). Fecal samples were collected within 24 h before, and after two in-lab nights, of either NS or PSD. In addition, participants underwent an oral glucose tolerance test following each sleep intervention. Results: Microbiota composition analysis (V4 16S rRNA gene sequencing) revealed that after two days of PSD vs. after two days of NS, individuals exhibited an increased Firmicutes:Bacteroidetes ratio, higher abundances of the families Coriobacteriaceae and Erysipelotrichaceae, and lower abundance of Tenericutes (all P < 0.05) – previously all associated with metabolic perturbations in animal or human models. However, no PSD vs. NS effect on beta diversity or on fecal short-chain fatty acid concentrations was found. Fasting and postprandial insulin sensitivity decreased after PSD vs. NS (all P < 0.05). Discussion: Our findings demonstrate that short-term sleep loss induces subtle effects on human microbiota. To what extent the observed changes to the microbial community contribute to metabolic consequences of sleep loss warrants further investigations in larger and more prolonged sleep studies, to also assess how sleep loss impacts the microbiota in individuals who already are metabolically compromised. Author Video: Author Video Watch what authors say about their articles Keywords: Bacteroidetes, Firmicutes, Insulin resistance, Intestinal microbiome, Short-chain fatty acid, Sleep restrictio

High-density capacitors for SiP and SoC applications based on three-dimensional integrated metal-isolator-metal structures

This paper focuses on zirconia and TiN based metal-isolator-metal capacitors integrated in immediate vicinity to the Si substrate. A high capacitance density is aimed by significant area enhancement realized through silicon pattering. By material optimization the capacitors also withstand higher supply voltages and show excellent temperature and reliability performance independently of the 3D structure

Mitochondrial stress-induced GFRAL signaling controls diurnal food intake and anxiety-like behavior

Growth differentiation factor 15 (GDF15) is a mitochondrial stress-induced cytokine that modulates energy balance in an endocrine manner. However, the importance of its brainstem-restricted receptor GDNF family receptor alpha-like (GFRAL) to mediate endocrine GDF15 signaling to the brain upon mitochondrial dysfunction is still unknown. Using a mouse model with muscle-specific mitochondrial dysfunction, we here show that GFRAL is required for activation of systemic energy metabolism via daytime-restricted anorexia but not responsible for muscle wasting. We further find that muscle mitochondrial stress response involves a GFRAL-dependent induction of hypothalamic corticotropin-releasing hormone, without elevated corticosterone levels. Finally, we identify that GFRAL signaling governs an anxiety-like behavior in male mice with muscle mitochondrial dysfunction, with females showing a less robust GFRAL-dependent anxiety-like phenotype. Together, we here provide novel evidence of a mitochondrial stress-induced muscle–brain crosstalk via the GDF15-GFRAL axis to modulate food intake and anxiogenic behavior

Ferroelectric deep trench capacitors based on Al:HfO2 for 3D nonvolatile memory applications

Aiming for future nonvolatile memory applications the fabrication and electrical characterization of 3-dimensional trench capacitors based on ferroelectric HfO2 is reported. It will be shown that the ferroelectric properties of Al-doped HfO2 ultrathin films are preserved when integrated into 3-dimensional geometries. The Al:HfO2 thin films were deposited by ALD and electrical data were collected on trench capacitor arrays with a trench count up to 100k. Stable ferroelectric switching behavior was observed for all trench arrays fabricated and only minimal remanent polarization loss with increasing 3-dimensional area gain was observed. In addition these arrays were found to withstand 2 *109 endurance cycles at saturated hysteresis loops. With these report the 3D capability of ferroelectric HfO2 is confirmed and for the first time a feasible solution for the vertical integration of ferroelectric 1T/1C as well as 1T memories is presented

3,5-Diiodo-L-Thyronine (3,5-T2) Exerts Thyromimetic Effects on Hypothalamus-Pituitary-Thyroid Axis, Body Composition, and Energy Metabolism in Male Diet-Induced Obese Mice

Effective and safe antiobesity drugs are still needed in face of the obesity pandemic worldwide. Recent interventions in rodents revealed 3,5-diiodo-L-thyronine (3,5-T2) as a metabolically active iodothyronine affecting energy and lipid metabolism without thyromimetic side effects typically associated with T3 administration. Accordingly, 3,5-T2 has been proposed as a potential hypolipidemic agent for treatment of obesity and hepatic steatosis. In contrast to other observations, our experiments revealed dose-dependent thyromimetic effects of 3,5-T2 akin to those of T3 in diet-induced obese male C57BL/6J mice. 3,5-T2 treatment exerted a negative feedback regulation on the hypothalamus-pituitary-thyroid axis, similar to T3. This is demonstrated by decreased expression of genes responsive to thyroid hormones (TH) in pituitary resulting in a suppressed thyroid function with lower T4 and T3 concentrations in serum and liver of 3,5-T2-treated mice. Analyses of hepatic TH target genes involved in lipid metabolism revealed T3-like changes in gene expression and increased type I-deiodinase activity after application of 3,5-T2 (2.5 μg/g body weight). Reduced hepatic triglyceride and serum cholesterol concentrations reflected enhanced lipid metabolism. Desired increased metabolic rate and reduction of different fat depots were, however, compromised by increased food intake preventing significant body weight loss. Moreover, enlarged heart weights indicate potential cardiac side effects of 3,5-T2 beyond hepatic thyromimetic actions. Altogether, the observed thyromimetic effects of 3,5-T2 in several mouse TH target tissues raise concern about indiscriminate administration of 3,5-T2 as powerful natural hormone for the treatment of hyperlipidemia and pandemic obesity