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Abstract Aims Heart failure with preserved ejection fraction (HFpEF) is a multifactorial, multisystemic syndrome that involves alterations in lipid metabolism. This study aimed to test whether distinct plasma lipid profiles or lipid entities or both are associated with clinical and functional echocardiographic parameters in HFpEF. Methods and results We examined the human plasma lipidome in HFpEF patients (n = 18) with left ventricular ejection fraction ≥50% and N‐terminal pro‐brain natriuretic peptide (NT‐proBNP) >125 pg/mL and control subjects (n = 12) using mass spectrometry‐based shotgun lipidomics. The cohort included 8 women and 22 men with average age of 67.8 ± 8.6 SD. The control and disease groups were not significantly different with respect to age, body mass index, systolic and diastolic blood pressure, and waist‐to‐hip ratio. The disease group experienced more fatigue (P

Neurodegenerative diseases typically emerge after an extended prodromal period, underscoring the critical importance of initiating interventions during the early stages of brain aging to enhance later resilience. Changes in presynaptic active zone proteins (''PreScale'') are considered a dynamic, resilience-enhancing form of plasticity in the process of early, still reversible aging of the Drosophila brain. Aging, however, triggers significant changes not only of synapses but also mitochondria. While the two organelles are spaced in close proximity, likely reflecting a direct functional coupling in regard to ATP and Ca2+ homeostasis, the exact modes of coupling in the aging process remain to understood.We here show that genetic manipulations of mitochondrial functional status, which alters brain oxidative phosphorylation, ATP levels, or the production of reactive oxygen species (ROS), can bidirectionally regulate PreScale during early Drosophila brain aging. Conversely, genetic mimicry of PreScale resulted in decreased oxidative phosphorylation and ATP production, potentially due to reduced mitochondrial calcium (Ca2+) import.Our findings indicate the existence of a positive feedback loop where mitochondrial functional state and PreScale are reciprocally coupled to optimize protection during the early stages of brain aging.

Abstract Finerenone is a novel non-steroidal mineralocorticoid receptor (MR) antagonist (MRA) with high binding affinity, high MR selectivity and a short plasma half-life. In two major endpoint-driven clinical trials in patients with chronic kidney disease and type 2 diabetes mellitus (FIDELIO-DKD and FIGARO-DKD), finerenone induced significant cardiorenal protective actions, and has been recently approved for treatment of these patients. Heart failure with preserved ejection fraction (HFpEF) is a devastating clinical syndrome with increasing prevalence and poor prognosis. Pharmacological therapy of HFpEF is very limited and new therapeutic options are urgently needed. Finerenone has been shown to improve multiple pathophysiological parameters of HFpEF in preclinical models. In consonance, pre-specified subgroup analyses of FIDELIO-DKD and FIGARO-DKD suggested a potential beneficial effect of finerenone in HFpEF. This review will discuss the pharmacodynamic and -kinetic profile of finerenone. We will provide a general overview over the complex pathophysiology of HFpEF and data from pre-clinical studies, focusing on how finerenone improves multiple components of this pathophysiology. Finally, we will discuss current and future clinical trials with finerenone in heart failure patients focusing on HFpEF.

BackgroundObesity exerts multiple deleterious effects on the heart that may ultimately lead to cardiac failure. This study sought to characterize myocardial microstructure and function in an experimental model of obesity-related cardiac dysfunction.MethodsMale C57BL/6N mice were fed either a high-fat diet (HFD; 60 kcal% fat, n = 12) or standard control diet (9 kcal% fat, n = 10) for 15 weeks. At the end of the study period, cardiac function was assessed by ultra-high frequency echocardiography, and hearts were processed for further analyses. The three-dimensional myocardial microstructure was examined ex vivo at a spatial resolution of 100 × 100 × 100 μm3 by diffusion tensor magnetic resonance imaging (DT-MRI) at 7T. Myocardial deformation, diffusion metrics and fiber tract geometry were analyzed with respect to the different myocardial layers (subendocardium/subepicardium) and segments (base/mid-cavity/apex). Results were correlated with blood sample analyses, histopathology, and gene expression data.ResultsHFD feeding induced significantly increased body weight combined with a pronounced accumulation of visceral fat (body weight 42.3 ± 5.7 vs. 31.5 ± 2.2 g, body weight change 73.7 ± 14.8 vs. 31.1 ± 6.6%, both P < 0.001). Obese mice showed signs of diastolic dysfunction, whereas left-ventricular ejection fraction and fractional shortening remained unchanged (E/e’ 41.6 ± 16.6 vs. 24.8 ± 6.0, P < 0.01; isovolumic relaxation time 19 ± 4 vs. 14 ± 4 ms, P < 0.05). Additionally, global longitudinal strain was reduced in the HFD group (−15.1 ± 3.0 vs. −20.0 ± 4.6%, P = 0.01), which was mainly driven by an impairment in basal segments. However, histopathology and gene expression analyses revealed no myocardial fibrosis or differences in cardiomyocyte morphology. Mean diffusivity and eigenvalues of the diffusion tensor were lower in the basal subepicardium of obese mice as assessed by DT-MRI (P < 0.05). The three-dimensional fiber tract arrangement of the left ventricle (LV) remained preserved.ConclusionFifteen weeks of high-fat diet induced alterations in myocardial diffusion properties in mice, whereas no remodeling of the three-dimensional myofiber arrangement of the LV was observed. Obese mice showed reduced longitudinal strain and lower mean diffusivity predominantly in the left-ventricular base, and further investigation into the significance of this regional pattern is required.

Background Degenerative aortic valve (AoV) disease and resulting aortic stenosis are major clinical health problems. Murine models of valve disease are rare, resulting in a translational knowledge gap on underlying mechanisms, functional consequences, and potential therapies. Naïve New Zealand obese (NZO) mice were recently found to have a dramatic decline of left ventricular (LV) function at early age. Therefore, we aimed to identify the underlying cause of reduced LV function in NZO mice. Methods and Results Cardiac function and pulmonary hemodynamics of NZO and age‐matched C57BL/6J mice were monitored by serial echocardiographic examinations. AoVs in NZO mice demonstrated extensive thickening, asymmetric aortic leaflet formation, and cartilaginous transformation of the valvular stroma. Doppler echocardiography of the aorta revealed increased peak velocity profiles, holodiastolic flow reversal, and dilatation of the ascending aorta, consistent with aortic stenosis and regurgitation. Compensated LV hypertrophy deteriorated to decompensated LV failure and remodeling, as indicated by increased LV mass, interstitial fibrosis, and inflammatory cell infiltration. Elevated LV pressures in NZO mice were associated with lung congestion and cor pulmonale, evident as right ventricular dilatation, decreased right ventricular function, and increased mean right ventricular systolic pressure, indicative for the development of pulmonary hypertension and ultimately right ventricular failure. Conclusions NZO mice demonstrate as a novel murine model to spontaneously develop degenerative AoV disease, aortic stenosis, and the associated end organ damages of both ventricles and the lung. Closely mimicking the clinical scenario of degenerative AoV disease, the model may facilitate a better mechanistic understanding and testing of novel treatment strategies in degenerative AoV disease.

Summary: Cardiolipin (CL) is a major cardiac mitochondrial phospholipid maintaining regular mitochondrial morphology and function in cardiomyocytes. Cardiac CL production includes its biosynthesis and a CL remodeling process. Here we studied the impact of CL biosynthesis and the enzyme cardiolipin synthase (CLS) on cardiac function. CLS and cardiac CL species were significantly downregulated in cardiomyocytes following catecholamine-induced cardiac damage in mice, accompanied by increased oxygen consumption rates, signs of oxidative stress, and mitochondrial uncoupling. RNAi-mediated cardiomyocyte-specific knockdown of CLS in Drosophila melanogaster resulted in marked cardiac dilatation, severe impairment of systolic performance, and slower diastolic filling velocity assessed by fluorescence-based heart imaging. Finally, we showed that CL72:8 is significantly decreased in cardiac samples from patients with heart failure with reduced ejection fraction (HFrEF). In summary, we identified CLS as a regulator of cardiac function. Considering the cardiac depletion of CL species in HFrEF, pharmacological targeting of CLS may be a promising therapeutic approach.

Cannabinoids (CB) are implicated in cardiovascular diseases via the two main receptor subtypes CB1R and CB2R. This study investigated whether cannabinoids regulate the activity of matrix metalloproteases (MMP-2, MMP-9) in vascular smooth muscle cells (VSMCs) and in cells of cardiac origin (H9c2 cell line). The influence of CB1- and CB2 receptor stimulation or inhibition on cell proliferation, apoptosis and glucose uptake was also evaluated. We used four compounds that activate or block CB receptors: arachidonyl-2-chloroethylamide (ACEA)—CB1R agonist, rimonabant—CB1R antagonist, John W. Huffman (JWH133)—CB2R agonist and CB2R antagonist—6-Iodopravadoline (AM630). Treatment of cells with the CB2R agonist JWH133 decreased cytokine activated secretion of proMMP-2, MMP-2 and MMP-9, reduced Fas ligand and caspase-3-mediated apoptosis, normalized the expression of TGF-beta1 and prevented cytokine-induced increase in glucose uptake into the cell. CB1R inhibition with rimonabant showed similar protective properties as the CB2R agonist JWH133, but to a lesser extent. In conclusion, CB1R and CB2R exert opposite effects on cell glucose uptake, proteolysis and apoptosis in both VSMCs and H9c2 cells. The CB2R agonist JWH133 demonstrated the highest protective properties. These findings may pave the way to a new treatment of cardiovascular diseases, especially those associated with extracellular matrix degradation.

Abstract Echocardiography is the most commonly applied technique for non-invasive assessment of cardiac function in small animals. Manual tracing of endocardial borders is time consuming and varies with operator experience. Therefore, we aimed to evaluate a novel automated two-dimensional software algorithm (Auto2DE) for small animals and compare it to the standard use of manual 2D-echocardiographic assessment (2DE). We hypothesized that novel Auto2DE will provide rapid and robust data sets, which are in agreement with manually assessed data of animals. 2DE and Auto2DE were carried out using a high-resolution imaging-system for small animals. First, validation cohorts of mouse and rat cine loops were used to compare Auto2DE against 2DE. These data were stratified for image quality by a blinded expert in small animal imaging. Second, we evaluated 2DE and Auto2DE in four mouse models and four rat models with different cardiac pathologies. Automated assessment of LV function by 2DE was faster than conventional 2DE analysis and independent of operator experience levels. The accuracy of Auto2DE-assessed data in healthy mice was dependent on cine loop quality, with excellent agreement between Auto2DE and 2DE in cine loops with adequate quality. Auto2DE allowed for valid detection of impaired cardiac function in animal models with pronounced cardiac phenotypes, but yielded poor performance in diabetic animal models independent of image quality. Auto2DE represents a novel automated analysis tool for rapid assessment of LV function, which is suitable for data acquisition in studies with good and very good echocardiographic image quality, but presents systematic problems in specific pathologies.

Summary: Mitochondrial function declines during brain aging and is suspected to play a key role in age-induced cognitive decline and neurodegeneration. Supplementing levels of spermidine, a body-endogenous metabolite, has been shown to promote mitochondrial respiration and delay aspects of brain aging. Spermidine serves as the amino-butyl group donor for the synthesis of hypusine (Nε-[4-amino-2-hydroxybutyl]-lysine) at a specific lysine residue of the eukaryotic translation initiation factor 5A (eIF5A). Here, we show that in the Drosophila brain, hypusinated eIF5A levels decline with age but can be boosted by dietary spermidine. Several genetic regimes of attenuating eIF5A hypusination all similarly affect brain mitochondrial respiration resembling age-typical mitochondrial decay and also provoke a premature aging of locomotion and memory formation in adult Drosophilae. eIF5A hypusination, conserved through all eukaryotes as an obviously critical effector of spermidine, might thus be an important diagnostic and therapeutic avenue in aspects of brain aging provoked by mitochondrial decline.

Summary: The cross talk between adipose tissue and the heart has an increasing importance for cardiac function under physiological and pathological conditions. This study characterizes the role of fat body lipolysis for cardiac function in Drosophila melanogaster. Perturbation of the function of the key lipolytic enzyme, brummer (bmm), an ortholog of the mammalian ATGL (adipose triglyceride lipase) exclusively in the fly's fat body, protected the heart against starvation-induced dysfunction. We further provide evidence that this protection is caused by the preservation of glycerolipid stores, resulting in a starvation-resistant maintenance of energy supply and adequate cardiac ATP synthesis. Finally, we suggest that alterations of lipolysis are tightly coupled to lipogenic processes, participating in the preservation of lipid energy substrates during starvation. Thus, we identified the inhibition of adipose tissue lipolysis and subsequent energy preservation as a protective mechanism against cardiac dysfunction during catabolic stress.

Objectives: Cannabinoid receptors CB1R and CB2R are expressed in the vascular smooth muscle cells (VSMCs) and may contribute to vascular remodeling process (O’Sullivan, 2015). This study aimed to investigate the implication of CB1R and CB2R in the regulation of matrix metalloproteases MMP2 and MMP9, cell proliferation and apoptosis. Methods: Primary VSMCs of contractile type were derived from rat aorta. Following compounds were studied: the CB1R agonist arachidonyl-2-chloroethylamide (ACEA), the CB1R antagonist/inverse agonist rimonabant, the CB2R agonist JWH133, the CB2R antagonist/inverse agonist AM630. The cells were treated with compounds simultaneously with IL1α stimulation. MMP2 and MMP9 were analyzed 48h after treatment via gelatin zymography, Western blotting and immunofluorescence. Apoptotic markers FasL, Caspase-3 and TGFbeta1 were used. This experimental setup was repeated using IncuCyte cell imaging to evaluate cell proliferation and apoptosis. Results: The CB2R agonist JWH133 decreased the activity of proMMP9 (p < 0.05), abolished IL1α -induced up-regulation of proMMP9/MMP9 proteins, and decreased MMP2 activity by tendency (11%). JWH133 also decreased the number of apoptotic cells (p < 0.05). Accordingly, CB2R antagonist AM630 did not prevent MMP9 release. CB1R antagonist Rimonabant reduced activity of proMMP9 (35%) and MMP2 (4%) and abolished protein up-regulation of proMMP9/MMP9. CB1R stimulation with ACEA had an ambiguous effect. JWH133 and Rimonabant increased cell proliferation (p < 0,05) and decreased expression of apoptosis markers FasL and caspase-3. Conclusions: The CB2R agonist JWH133 and CB1R antagonist Rimonabant prevented release of MMP9 and cell death of VSMCs. Therefore, stimulation of the CB2R or blockade of the CB1R may be favorable by vascular outward remodeling processes.

Although heart failure following myocardial infarction (MI) represents a major health burden, underlying microstructural and functional changes remain incompletely understood. Here, we report on a case of unexpected MI after treatment with the catecholamine isoproterenol in an experimental imaging study in mice using different state-of-the-art imaging modalities. The decline in cardiac function was documented by ultrahigh-frequency echocardiography and speckle-tracking analyses. Myocardial microstructure was studied ex vivo at a spatial resolution of 100 × 100 × 100 μm3 using diffusion tensor magnetic resonance imaging (DT-MRI) and histopathologic analyses. Two weeks after ISO treatment, the animal showed an apical aneurysm accompanied by reduced radial strain in corresponding segments and impaired global systolic function. DT-MRI revealed a loss of contractile fiber tracts together with a disarray of remaining fibers as corresponding microstructural correlates. This preclinical case report provides valuable insights into pathophysiology and morphologic–functional relations of heart failure following MI using emerging imaging technologies.

Heart failure is one of the leading causes of death worldwide. New therapeutic concepts are urgently required to lower the burden of heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF), the two major forms of heart failure. Lipolytic processes are induced during the development of heart failure and occur in adipose tissue and multiple organs, including the heart. Increasing evidence suggests that cellular lipolysis, in particular, adipose triglyceride lipase (ATGL) activity, has an important function in cardiac (patho)physiology. This review summarizes the crucial role of cellular lipolysis for normal cardiac function and for the development of HFrEF and HFpEF. We discuss the most relevant pre-clinical studies and elaborate on the cardiac consequences of non-myocardial and myocardial lipolysis modulation. Finally, we critically analyze the therapeutic importance of pharmacological ATGL inhibition as a potential treatment option for HFrEF and/or HFpEF in the future.

Background Animal studies demonstrated that serelaxin lessens fibrosis in heart failure. This study assessed its effect on myocardial deformation using cardiac magnetic resonance and elucidated its relationship to gene regulation and histology in a mouse heart failure model. Methods and Results C57BL/6J mice were subjected to SHAM (n=4) or transverse aortic constriction (TAC). At week 10, TAC mice were randomized to receive either serelaxin (0.5 mg/kg per day; n=11) or vehicle (n=13) for 4 weeks. Cardiac magnetic resonance imaging was performed at baseline and repeated at the end of the study (week 14). Cine images were used to calculate left ventricular (LV) global longitudinal, circumferential, and radial strain. Hearts were examined for histology and gene expression. Compared with SHAM, mice 10 weeks after TAC showed increased LV mass with significant decreases in LV deformation parameters, indicating subclinical deterioration of myocardial function. At week 14, TAC mice given serelaxin demonstrated significant improvements in all LV strain parameters and no decrease in LV stroke volume and ejection fraction compared with TAC mice given vehicle. A significant positive correlation between global circumferential strain and the extent of myocardial fibrosis was found, and global circumferential strain correlated significantly with the expression of heart failure genes in serelaxin‐treated mice. Conclusions Serelaxin improved cardiac magnetic resonance–derived myocardial deformation parameters as well as histomorphometric and gene expression findings in mice with heart failure. Cardiac magnetic resonance–derived myocardial mechanics correlate with histology and gene expression, stressing its utilization in myocardial remodeling.

Abstract Background The assessment of ventricular volumes using conventional echocardiography methods is limited with regards to the need of geometrical assumptions. In the present study, we aimed to evaluate a novel commercial system for three-dimensional echocardiography (3DE) in preclinical models by direct comparison with conventional 1D- and 2D-echocardiography (1DE; 2DE) and the gold-standard technique magnetic resonance imaging (MRI). Further, we provide a standard operating protocol for image acquisition and analysis with 3DE. Methods 3DE was carried out using a 30 MHz center frequency transducer coupled to a Vevo®3100 Imaging System. We evaluated under different experimental conditions: 1) in vitro phantom measurements served as controlled setting in which boundaries were clearly delineated; 2) a validation cohort composed of healthy C57BL/6 J mice and New Zealand Obese (NZO) mice was used in order to validate 3DE against cardiac MRI; 3) a standard mouse model of pressure overload induced-heart failure was investigated to estimate the value of 3DE. Results First, in vitro volumetry revealed good agreement between 3DE assessed volumes and the MRI-assessed volumes. Second, cardiac volume determination with 3DE showed smaller mean differences compared to cardiac MRI than conventional 1DE and 2DE. Third, 3DE was suitable to detect reduced ejection fractions in heart failure mice. Fourth, inter- and intra-observer variability of 3DE showed good to excellent agreement regarding absolute volumes in healthy mice, whereas agreement rates for the relative metrics ejection fraction and stroke volume demonstrated good to moderate observer variabilities. Conclusions 3DE provides a novel method for accurate volumetry in small animals without the need for spatial assumptions, demonstrating a technique for an improved analysis of ventricular function. Further validation work and highly standardized image analyses are required to increase reproducibility of this approach.

Cardiac remodeling and contractile dysfunction are leading causes in hypertrophy-associated heart failure (HF), increasing with a population’s rising age. A hallmark of aged and diseased hearts is the accumulation of modified proteins caused by an impaired autophagy-lysosomal-pathway. Although, autophagy inducer rapamycin has been described to exert cardioprotective effects, it remains to be shown whether these effects can be attributed to improved cardiomyocyte autophagy and contractility. In vivo hypertrophy was induced by transverse aortic constriction (TAC), with mice receiving daily rapamycin injections beginning six weeks after surgery for four weeks. Echocardiographic analysis demonstrated TAC-induced HF and protein analyses showed abundance of modified proteins in TAC-hearts after 10 weeks, both reduced by rapamycin. In vitro, cardiomyocyte hypertrophy was mimicked by endothelin 1 (ET-1) and autophagy manipulated by silencing Atg5 in neonatal cardiomyocytes. ET-1 and siAtg5 decreased Atg5–Atg12 and LC3-II, increased natriuretic peptides, and decreased amplitude and early phase of contraction in cardiomyocytes, the latter two evaluated using ImageJ macro Myocyter recently developed by us. ET-1 further decreased cell contractility in control but not in siAtg5 cells. In conclusion, ET-1 decreased autophagy and cardiomyocyte contractility, in line with siAtg5-treated cells and the results of TAC-mice demonstrating a crucial role for autophagy in cardiomyocyte contractility and cardiac performance.

Background: Obesity is a risk factor for diseases including type 2 diabetes mellitus (T2DM) and cardiovascular disorders. Diabetes itself contributes to cardiac damage. Thus, studying cardiovascular events and establishing therapeutic intervention in the period of type T2DM onset and manifestation are of highest importance. Mitochondrial dysfunction is one of the pathophysiological mechanisms leading to impaired cardiac function.Methods: An adequate animal model for studying pathophysiology of T2DM is the New Zealand Obese (NZO) mouse. These mice were maintained on a high-fat diet (HFD) without carbohydrates for 13 weeks followed by 4 week HFD with carbohydrates. NZO mice developed severe obesity and only male mice developed manifest T2DM. We determined cardiac phenotypes and mitochondrial function as well as cardiomyocyte signaling in this model.Results: The development of an obese phenotype and T2DM in male mice was accompanied by an impaired systolic function as judged by echocardiography and MyH6/7 expression. Moreover, the mitochondrial function only in male NZO hearts was significantly reduced and ERK1/2 and AMPK protein levels were altered.Conclusions: This is the first report demonstrating that the cardiac phenotype in male diabetic NZO mice is associated with impaired cardiac energy function and signaling events.

Adipose tissue lipolysis occurs during the development of heart failure as a consequence of chronic adrenergic stimulation. However, the impact of enhanced adipose triacylglycerol hydrolysis mediated by adipose triglyceride lipase (ATGL) on cardiac function is unclear. To investigate the role of adipose tissue lipolysis during heart failure, we generated mice with tissue-specific deletion of ATGL (atATGL-KO). atATGL-KO mice were subjected to transverse aortic constriction (TAC) to induce pressure-mediated cardiac failure. The cardiac mouse lipidome and the human plasma lipidome from healthy controls (n = 10) and patients with systolic heart failure (HFrEF, n = 13) were analyzed by MS-based shotgun lipidomics. TAC-induced increases in left ventricular mass (LVM) and diastolic LV inner diameter were significantly attenuated in atATGL-KO mice compared to wild type (wt) -mice. More importantly, atATGL-KO mice were protected against TAC-induced systolic LV failure. Perturbation of lipolysis in the adipose tissue of atATGL-KO mice resulted in the prevention of the major cardiac lipidome changes observed after TAC in wt-mice. Profound changes occurred in the lipid class of phosphatidylethanolamines (PE) in which multiple PE-species were markedly induced in failing wt-hearts, which was attenuated in atATGL-KO hearts. Moreover, selected heart failure-induced PE species in mouse hearts were also induced in plasma samples from patients with chronic heart failure. TAC-induced cardiac PE induction resulted in decreased PC/ PE-species ratios associated with increased apoptotic marker expression in failing wt-hearts, a process absent in atATGL-KO hearts. Perturbation of adipose tissue lipolysis by ATGL-deficiency ameliorated pressure-induced heart failure and the potentially deleterious cardiac lipidome changes that accompany this pathological process, namely the induction of specific PE species. Non-cardiac ATGL-mediated modulation of the cardiac lipidome may play an important role in the pathogenesis of chronic heart failure.

Objective: Insulin resistance can be triggered by enhanced dephosphorylation of the insulin receptor or downstream components in the insulin signaling cascade through protein tyrosine phosphatases (PTPs). Downregulating density-enhanced phosphatase-1 (DEP-1) resulted in an improved metabolic status in previous analyses. This phenotype was primarily caused by hepatic DEP-1 reduction. Methods: Here we further elucidated the role of DEP-1 in glucose homeostasis by employing a conventional knockout model to explore the specific contribution of DEP-1 in metabolic tissues. Ptprj−/− (DEP-1 deficient) and wild-type C57BL/6 mice were fed a low-fat or high-fat diet. Metabolic phenotyping was combined with analyses of phosphorylation patterns of insulin signaling components. Additionally, experiments with skeletal muscle cells and muscle tissue were performed to assess the role of DEP-1 for glucose uptake. Results: High-fat diet fed-Ptprj−/− mice displayed enhanced insulin sensitivity and improved glucose tolerance. Furthermore, leptin levels and blood pressure were reduced in Ptprj−/− mice. DEP-1 deficiency resulted in increased phosphorylation of components of the insulin signaling cascade in liver, skeletal muscle and adipose tissue after insulin challenge. The beneficial effect on glucose homeostasis in vivo was corroborated by increased glucose uptake in skeletal muscle cells in which DEP-1 was downregulated, and in skeletal muscle of Ptprj−/− mice. Conclusion: Together, these data establish DEP-1 as novel negative regulator of insulin signaling.

The effects of the selective angiotensin AT2 receptor agonist, compound 21 (C21), on abdominal aortic aneurysm (AAA) formation were investigated in normotensive Wistar rats. AAA was induced by perfusion of isolated aortic segments with elastase (Anidjar/Dobrin model). Treatment with C21 (0.03 and 0.3 mg/kg daily) was started after surgery and continued for 14 days. Sham operated animals and vehicle-treated animals after aneurysm induction (AI) served as controls. Aortic diameter and wall properties (distensibility, pulse propagation velocity) were measured infrarenally via ultrasound. Hemodynamic parameters, aortic tissue protein expression and serum cytokines were analysed. On day 14 post AI, aortic diameter of vehicle-treated animals was increased 1,6-fold compared to sham operated rats (p < 0.0001). C21 (0.03 mg/kg) decreased aortic diameter in comparison to vehicle (1.9 mm ± 0.06 vs. 2.65 mm ± 0.06; p < 0.0001). Infrarenal blood velocity and aortic distensibility were reduced, whereas aortic wall stiffness was increased post AI. These alterations were significantly ameliorated by treatment with C21 (p < 0.0001; p < 0.0001; p < 0.05). Blood pressure and cardiac contractility were not altered. Protein expression of IL1 beta, NF kappa B, MMP9, TGF-beta1 and MLKL in the aorta was significantly (p < 0.05) down-regulated in the C21 group compared with vehicle. In primary rat vascular smooth muscle cells, the release of MMP9, TGF-beta1 and MLKL was significantly diminished after C21 (1μM) treatment. Serum concentration of TGF-beta1 was also decreased by C21 in comparison to vehicle (p < 0.01). In conclusion, AT2 receptor stimulation with C21 prevented extracellular matrix degradation, maintained vascular integrity of the aorta and prevented AAA progression.

Matrix metalloproteinase (MMP)-dependent extracellular matrix (ECM) remodeling is a key feature in cardiometabolic syndrome-associated adipogenesis and atherosclerosis. Activation of membrane-tethered (MT) 1-MMP depends on furin (PCSK3). However, the regulation and function of the natural furin-inhibitor serpinB8 and thus furin/MT1-MMP-activity in obesity-related tissue inflammation/remodeling is unknown. Here we aimed to determine the role of serpinB8/furin in obesity-associated chronic inflammation.Monocyte → macrophage transformation was characterized by decreases in serpinB8 and increases in furin/MT1-MMP. Rescue of serpinB8 by protein overexpression inhibited furin-dependent pro-MT1-MMP activation in macrophages, supporting its role as a furin-inhibitor. Obese white adipose tissue-facilitated macrophage migration was inhibited by furin- and MMP-inhibition, stressing the importance of the furin-MMP axis in fat tissue inflammation/remodeling. Monocytes from obese patients (body mass index (BMI) >30kg/m(2)) had higher furin, MT1-MMP, and resistin gene expression compared to normal weight individuals (BMI

BackgroundSuccessful reduction of body weight (BW) is often followed by recidivism to obesity. BW-changes including BW-loss and -regain is associated with marked alterations in energy expenditure (EE) and adipose tissue (AT) metabolism. Since these processes are sex-specifically controlled, we investigated sexual dimorphisms in metabolic processes during BW-dynamics (gain-loss-regain).Research designObesity was induced in C57BL/6J male (m) and female (f) mice by 15 weeks high-fat diet (HFD) feeding. Subsequently BW was reduced (-20%) by caloric restriction (CR) followed by adaptive feeding, and a regain-phase. Measurement of EE, body composition, blood/organ sampling were performed after each feeding period. Lipolysis was analyzed ex-vivo in gonadal AT.ResultsMale mice exhibited accelerated BW-gain compared to females (relative BW-gain m:140.5±3.2%; f:103.7±6.5%; pConclusionThe present study shows sex-specific dynamics during BW-gain-loss-regain. Female mice responded to CR with an increase in lipolytic activity, and augmented lipid-oxidation leading to more efficient weight loss. These processes likely involve ERα-dependent signaling in AT and sexual dimorphic regulation of genes involved in lipid metabolism.

Estrogen receptors (ER) are important regulators of metabolic diseases such as obesity and insulin resistance (IR). While ERalpha seems to have a protective role in such diseases, the function of ERbeta is not clear. To characterize the metabolic function of ERbeta, we investigated its molecular interaction with a master regulator of insulin signaling/glucose metabolism, the PPARgamma, in vitro and in high-fat diet (HFD)-fed ERbeta -/- mice (betaERKO) mice. Our in vitro experiments showed that ERbeta inhibits ligand-mediated PPARgamma-transcriptional activity. That resulted in a blockade of PPARgamma-induced adipocytic gene expression and in decreased adipogenesis. Overexpression of nuclear coactivators such as SRC1 and TIF2 prevented the ERbeta-mediated inhibition of PPARgamma activity. Consistent with the in vitro data, we observed increased PPARgamma activity in gonadal fat from HFD-fed betaERKO mice. In consonance with enhanced PPARgamma activation, HFD-fed betaERKO mice showed increased body weight gain and fat mass in the presence of improved insulin sensitivity. To directly demonstrate the role of PPARgamma in HFD-fed betaERKO mice, PPARgamma signaling was disrupted by PPARgamma antisense oligonucleotide (ASO). Blockade of adipose PPARgamma by ASO reversed the phenotype of betaERKO mice with an impairment of insulin sensitization and glucose tolerance. Finally, binding of SRC1 and TIF2 to the PPARgamma-regulated adiponectin promoter was enhanced in gonadal fat from betaERKO mice indicating that the absence of ERbeta in adipose tissue results in exaggerated coactivator binding to a PPARgamma target promoter. Collectively, our data provide the first evidence that ERbeta-deficiency protects against diet-induced IR and glucose intolerance which involves an augmented PPARgamma signaling in adipose tissue. Moreover, our data suggest that the coactivators SRC1 and TIF2 are involved in this interaction. Impairment of insulin and glucose metabolism by ERbeta may have significant implications for our understanding of hormone receptor-dependent pathophysiology of metabolic diseases, and may be essential for the development of new ERbeta-selective agonists.