Exploration of New Therapies for Heart Failure Targeting Age-Related Mechanisms

Evidence indicates a role of cellular senescence and systemic insulin resistance (hyperinsulinemia) in the pathogenesis of age-related cardiovascular-metabolic disorders, including heart failure, atherosclerotic diseases, obesity, and diabetes. "Metabolic remodeling" is one of the keywords for aging research, and studies with brown adipose tissue have shown that maintaining the homeostasis of this organ is crucial to suppressing the progression of pathologies in obesity and heart failure. The mechanisms contributing to the synchronization of aging (sync-aging) are mysterious and interesting. "Senometabolite" or "senoprotein" are defined as circulating molecules that have causal roles in sync-aging, which requires the establishment of new concepts: age-related fibrotic disorders (A-FiDs), and senometabolite-related disorders (SRDs). Globally, researchers are active in comprehensive and conclusive studies targeting age-related circulating molecules. Recently, the senolytic approach opened a new avenue for aging research. Senolysis, mediated through a genetic/pharmacologic/vaccination approach, reversed aging and pathologies in age-related diseases. Suppression of prosenescent molecules (senocules) and senolysis, the specific depletion of senescent cells, will become next-generation therapies for cardiovascular diseases.

Search for the Majorana Nature of Neutrinos in the Inverted Mass Ordering Region with KamLAND-Zen

The KamLAND-Zen experiment has provided stringent constraints on the neutrinoless double-beta (0νββ) decay half-life in ^{136}Xe using a xenon-loaded liquid scintillator. We report an improved search using an upgraded detector with almost double the amount of xenon and an ultralow radioactivity container, corresponding to an exposure of 970 kg yr of ^{136}Xe. These new data provide valuable insight into backgrounds, especially from cosmic muon spallation of xenon, and have required the use of novel background rejection techniques. We obtain a lower limit for the 0νββ decay half-life of T_{1/2}^{0ν}>2.3×10^{26}  yr at 90% C.L., corresponding to upper limits on the effective Majorana neutrino mass of 36-156 meV using commonly adopted nuclear matrix element calculations.

Endothelial SIRT-1 has a critical role in the maintenance of capillarization in brown adipose tissue

Brown adipose tissue (BAT) has critical roles in thermogenesis and systemic metabolism. Capillary rarefaction was reported to develop in BAT with dietary obesity, and previous studies showed that suppression of vascular endothelial growth factor A (VEGF-A) reduced capillary density in BAT, promoting the functional decline of this organ. Capillarization is regulated through the balance between angiogenesis and vasculogenesis on the one hand and apoptosis of endothelial cells (ECs) on the other; however, the role of EC apoptosis in BAT remained to be explored. In studies testing the role of boysenberry polyphenols (BoyP) in BAT, we found that BoyP decreased EC apoptosis, enhanced capillarization in BAT, and ameliorated dietary BAT dysfunction, which was associated with the upregulation of nicotinamide adenine dinucleotide-dependent protein deacetylase sirtuin 1 (SIRT-1) in ECs. Our studies suggest that EC SIRT-1 would be one of the potential targets of BoyP that contributes to BAT capillarization and function.

Brown adipose tissue dysfunction promotes heart failure via a trimethylamine N-oxide-dependent mechanism

Low body temperature predicts a poor outcome in patients with heart failure, but the underlying pathological mechanisms and implications are largely unknown. Brown adipose tissue (BAT) was initially characterised as a thermogenic organ, and recent studies have suggested it plays a crucial role in maintaining systemic metabolic health. While these reports suggest a potential link between BAT and heart failure, the potential role of BAT dysfunction in heart failure has not been investigated. Here, we demonstrate that alteration of BAT function contributes to development of heart failure through disorientation in choline metabolism. Thoracic aortic constriction (TAC) or myocardial infarction (MI) reduced the thermogenic capacity of BAT in mice, leading to significant reduction of body temperature with cold exposure. BAT became hypoxic with TAC or MI, and hypoxic stress induced apoptosis of brown adipocytes. Enhancement of BAT function improved thermogenesis and cardiac function in TAC mice. Conversely, systolic function was impaired in a mouse model of genetic BAT dysfunction, in association with a low survival rate after TAC. Metabolomic analysis showed that reduced BAT thermogenesis was associated with elevation of plasma trimethylamine N-oxide (TMAO) levels. Administration of TMAO to mice led to significant reduction of phosphocreatine and ATP levels in cardiac tissue via suppression of mitochondrial complex IV activity. Genetic or pharmacological inhibition of flavin-containing monooxygenase reduced the plasma TMAO level in mice, and improved cardiac dysfunction in animals with left ventricular pressure overload. In patients with dilated cardiomyopathy, body temperature was low along with elevation of plasma choline and TMAO levels. These results suggest that maintenance of BAT homeostasis and reducing TMAO production could be potential next-generation therapies for heart failure.

Coagulation factors promote brown adipose tissue dysfunction and abnormal systemic metabolism in obesity

Brown adipose tissue (BAT) has a role in maintaining systemic metabolic health in rodents and humans. Here, we show that metabolic stress induces BAT to produce coagulation factors, which then-together with molecules derived from the circulation-promote BAT dysfunction and systemic glucose intolerance. When mice were fed a high-fat diet (HFD), the levels of tissue factor, coagulation Factor VII (FVII), activated coagulation Factor X (FXa), and protease-activated receptor 1 (PAR1) expression increased significantly in BAT. Genetic or pharmacological suppression of coagulation factor-PAR1 signaling in BAT ameliorated its whitening and improved thermogenic response and systemic glucose intolerance in mice with dietary obesity. Conversely, the activation of coagulation factor-PAR1 signaling in BAT caused mitochondrial dysfunction in brown adipocytes and systemic glucose intolerance in mice fed normal chow. These results indicate that BAT produces endogenous coagulation factors that mediate pleiotropic effects via PAR1 signaling under metabolic stress.

Differing impact of phosphoglycerate mutase 1-deficiency on brown and white adipose tissue

Brown adipose tissue (BAT) is a metabolically active organ that contributes to the thermogenic response to cold exposure. In addition, other thermogenic cells termed beige adipocytes are generated in white adipose tissue (WAT) by cold exposure. Although activation of brown/beige adipose tissue is associated with mobilization of both glucose and lipids, few studies have focused on the role of glycolytic enzymes in regulating adipose tissue function. We generated mouse models with specific deletion of the glycolytic enzyme phosphoglycerate mutase 1 (PGAM1) from adipose tissue. Deletion of Pgam1 from both BAT and WAT promoted whitening of BAT with beiging of visceral WAT, whereas deletion of Pgam1 from BAT alone led to whitening of BAT without beiging of WAT. Our results demonstrate a potential role of glycolytic enzymes in beiging of visceral WAT and suggest that PGAM1 would be a novel therapeutic target in obesity and diabetes.

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Pgam1 deletion leads to whitening of brown adipose tissue

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Pgam1 deletion promotes beiging of visceral white adipose tissue (WAT)

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Pgam1 deletion-induced beiging is associated with increased levels of amino acids

Cereblon contributes to cardiac dysfunction by degrading Cav1.2α

AIMS

Cereblon (CRBN) is a substrate receptor of the E3 ubiquitin ligase complex that was reported to target ion channel proteins. L-type voltage-dependent Ca2+ channel (LTCC) density and dysfunction is a critical player in heart failure with reduced ejection fraction (HFrEF). However, the underlying cellular mechanisms by which CRBN regulates LTCC subtype Cav1.2α during cardiac dysfunction remain unclear. Here, we explored the role of CRBN in HFrEF by investigating the direct regulatory role of CRBN in Cav1.2α activity and examining how it can serve as a target to address myocardial dysfunction.

METHODS AND RESULTS

Cardiac tissues from HFrEF patients exhibited increased levels of CRBN compared with controls. In vivo and ex vivo studies demonstrated that whole-body CRBN knockout (CRBN-/-) and cardiac-specific knockout mice (Crbnfl/fl/Myh6Cre+) exhibited enhanced cardiac contractility with increased LTCC current (ICaL) compared with their respective controls, which was modulated by the direct interaction of CRBN with Cav1.2α. Mechanistically, the Lon domain of CRBN directly interacted with the N-terminal of Cav1.2α. Increasing CRBN levels enhanced the ubiquitination and proteasomal degradation of Cav1.2α and decreased ICaL. In contrast, genetic or pharmacological depletion of CRBN via TD-165, a novel PROTAC-based CRBN degrader, increased surface expression of Cav1.2α and enhanced ICaL. Low CRBN levels protected the heart against cardiomyopathy in vivo.

CONCLUSION

Cereblon selectively degrades Cav1.2α, which in turn facilitates cardiac dysfunction. A targeted approach or an efficient method of reducing CRBN levels could serve as a promising strategy for HFrEF therapeutics.

KEY QUESTION

KEY FINDING

TAKE-HOME MESSAGE

Cereblon modulates cardiac function by altering Cav1.2α current density and CRBN-targeting therapy could serve as a novel strategy for future HFrEF therapeutics.

Role of circulating molecules in age-related cardiovascular and metabolic disorders

Studies analyzing heterochronic parabiosis mice models showed that molecules in the blood of young mice rejuvenate aged mice. Therefore, blood-based therapies have become one of the therapeutic approaches to be considered for age-related diseases. Blood includes numerous biologically active molecules such as proteins, metabolites, hormones, miRNAs, etc. and accumulating evidence indicates some of these change their concentration with chronological aging or age-related disorders. The level of some circulating molecules showed a negative or positive correlation with all-cause mortality, cardiovascular events, or metabolic disorders. Through analyses of clinical/translation/basic research, some molecules were focused on as therapeutic targets. One approach is the supplementation of circulating anti-aging molecules. Favorable results in preclinical studies let some molecules to be tested in humans. These showed beneficial or neutral results, and some were inconsistent. Studies with rodents and humans indicate circulating molecules can be recognized as biomarkers or therapeutic targets mediating their pro-aging or anti-aging effects. Characterization of these molecules with aging, testing their biological effects, and finding mimetics of young systemic milieu continue to be an interesting and important research topic to be explored.

Capillaries as a Therapeutic Target for Heart Failure

Prognosis of heart failure remains poor, and it is urgent to find new therapies for this critical condition. Oxygen and metabolites are delivered through capillaries; therefore, they have critical roles in the maintenance of cardiac function. With aging or age-related disorders, capillary density is reduced in the heart, and the mechanisms involved in these processes were reported to suppress capillarization in this organ. Studies with rodents showed capillary rarefaction has causal roles for promoting pathologies in failing hearts. Drugs used as first-line therapies for heart failure were also shown to enhance the capillary network in the heart. Recently, the approach with senolysis is attracting enthusiasm in aging research. Genetic or pharmacological approaches concluded that the specific depletion of senescent cells, senolysis, led to reverse aging phenotype. Reagents mediating senolysis are described to be senolytics, and these compounds were shown to ameliorate cardiac dysfunction together with enhancement of capillarization in heart failure models. Studies indicate maintenance of the capillary network as critical for inhibition of pathologies in heart failure.

Senolytic vaccination improves normal and pathological age-related phenotypes and increases lifespan in progeroid mice

Elimination of senescent cells (senolysis) was recently reported to improve normal and pathological changes associated with aging in mice^1,2. However, most senolytic agents inhibit antiapoptotic pathways³, raising the possibility of off-target effects in normal tissues. Identification of alternative senolytic approaches is therefore warranted. Here we identify glycoprotein nonmetastatic melanoma protein B (GPNMB) as a molecular target for senolytic therapy. Analysis of transcriptome data from senescent vascular endothelial cells revealed that GPNMB was a molecule with a transmembrane domain that was enriched in senescent cells (seno-antigen). GPNMB expression was upregulated in vascular endothelial cells and/or leukocytes of patients and mice with atherosclerosis. Genetic ablation of Gpnmb-positive cells attenuated senescence in adipose tissue and improved systemic metabolic abnormalities in mice fed a high-fat diet, and reduced atherosclerotic burden in apolipoprotein E knockout mice on a high-fat diet. We then immunized mice against Gpnmb and found a reduction in Gpnmb-positive cells. Senolytic vaccination also improved normal and pathological phenotypes associated with aging, and extended the male lifespan of progeroid mice. Our results suggest that vaccination targeting seno-antigens could be a potential strategy for new senolytic therapies.

Altered microbiota by a high-fat diet accelerates lethal myeloid hematopoiesis associated with systemic SOCS3 deficiency

The suppressors of cytokine signaling (SOCS) proteins are negative regulators of cytokine signaling required to prevent excessive cellular responses. In particular, SOCS3 is involved in the regulation of metabolic syndromes, such as obesity and diabetes, by suppressing leptin and insulin signals. SOCS3 also suppresses the inflammatory response associated with metabolic stress, but this specific role remains undefined. Wild-type mice on a high-fat diet (HFD) exhibited only fatty liver, whereas systemic deletion of SOCS3 resulted in excessive myeloid hematopoiesis and hepatic inflammation. In addition, depletion of the gut microbiota resulted in considerable improvement in excess granulopoiesis and splenomegaly, halting the progression of systemic inflammation in SOCS3KO mice on the HFD. This result suggests that intestinal dysbiosis is involved in inflammation associated with SOCS3KO. Although contributing to diet-induced obesity and fatty liver, SOCS3 is nevertheless critical to suppress excess myeloid hematopoiesis and severe systemic inflammation associated with intestinal dysbiosis on HFD.

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SOCS3 suppresses severe systemic inflammation associated with high-fat diet

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SOCS3 deficiency on high-fat diet accelerates excess myeloid hematopoiesis

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SOCS3 controls gut dysbiosis on high-fat diet

Empagliflozin maintains capillarization and improves cardiac function in a murine model of left ventricular pressure overload

Patients with type 2 diabetes treated with Sodium glucose transporter 2 (SGLT2) inhibitors show reduced mortality and hospitalization for heart failure (HF). SGLT2 inhibitors are considered to activate multiple cardioprotective pathways; however, underlying mechanisms are not fully described. This study aimed to elucidate the underlying mechanisms of the beneficial effects of SGLT2 inhibitors on the failing heart. We generated a left ventricular (LV) pressure overload model in C57BL/6NCrSlc mice by transverse aortic constriction (TAC) and examined the effects of empagliflozin (EMPA) in this model. We conducted metabolome and transcriptome analyses and histological and physiological examinations. EMPA administration ameliorated pressure overload-induced systolic dysfunction. Metabolomic studies showed that EMPA increased citrulline levels in cardiac tissue and reduced levels of arginine, indicating enhanced metabolism from arginine to citrulline and nitric oxide (NO). Transcriptome suggested possible involvement of the insulin/AKT pathway that could activate NO production through phosphorylation of endothelial NO synthase (eNOS). Histological examination of the mice showed capillary rarefaction and endothelial apoptosis after TAC, both of which were significantly improved by EMPA treatment. This improvement was associated with enhanced expression phospho-eNOS and NO production in cardiac endothelial cells. NOS inhibition attenuated these cardioprotective effects of EMPA. The in vitro studies showed that catecholamine-induced endothelial apoptosis was inhibited by NO, arginine, or AKT activator. EMPA activates the AKT/eNOS/NO pathway, which helps to suppress endothelial apoptosis, maintain capillarization and improve systolic dysfunction during LV pressure overload.

Association of adipokines with frailty in heart failure

Background

Frailty is a multifactorial physiological syndrome most often associated with age but which has received increasing recognition as a component of chronic illnesses such as heart failure. Patients with heart failure are likely to be frail, irrespective of their age. Adipokine dysregulation, which is associated with frailty, occurs in patients with heart failure. In this study, we tested the hypothesis that adipokines are associated with skeletal muscle and bone mineral density that change lead to frailty in patients with heart failure.

Methods

Thirty-five patients with heart failure (age, 67 ± 14 years; 25 males; left ventricular ejection fraction, 45 ± 19%) were included. Serum adipokine levels, physical performance, and body composition were measured.

Results

Adiponectin and leptin were inversely correlated with grip strength. Adiponectin was inversely correlated with bone mineral density. Leptin was positively correlated with fat mass. Adipokines were not correlated with skeletal muscle mass.

Conclusions

Adipokines were associated with grip strength and bone mineral density in patients with heart failure. Adipokine dysregulation may play a role in the development of frailty in heart failure.

Cardiac mitofusin-1 is reduced in non-responding patients with idiopathic dilated cardiomyopathy

Prognosis of severe heart failure remains poor. Urgent new therapies are required. Some heart failure patients do not respond to established multidisciplinary treatment and are classified as “non-responders”. The outcome is especially poor for non-responders, and underlying mechanisms are largely unknown. Mitofusin-1 (Mfn1), a mitochondrial fusion protein, is significantly reduced in non-responding patients. This study aimed to elucidate the role of Mfn1 in the failing heart. Twenty-two idiopathic dilated cardiomyopathy (IDCM) patients who underwent endomyocardial biopsy of intraventricular septum were included. Of the 22 patients, 8 were non-responders (left ventricular (LV) ejection fraction (LVEF) of < 10% improvement at late phase follow-up). Electron microscopy (EM), quantitative PCR, and immunofluorescence studies were performed to explore the biological processes and molecules involved in failure to respond. Studies in cardiac specific Mfn1 knockout mice (c-Mfn1 KO), and in vitro studies with neonatal rat ventricular myocytes (NRVMs) were also conducted. A significant reduction in mitochondrial size in cardiomyocytes, and Mfn1, was observed in non-responders. A LV pressure overload with thoracic aortic constriction (TAC) c-Mfn1 KO mouse model was generated. Systolic function was reduced in c-Mfn1 KO mice, while mitochondria alteration in TAC c-Mfn1 KO mice increased. In vitro studies in NRVMs indicated negative regulation of Mfn1 by the β-AR/cAMP/PKA/miR-140-5p pathway resulting in significant reduction in mitochondrial respiration of NRVMs. The level of miR140-5p was increased in cardiac tissues of non-responders. Mfn1 is a biomarker of heart failure in non-responders. Therapies targeting mitochondrial dynamics and homeostasis are next generation therapy for non-responding heart failure patients.

Phosphorylation in Novel Mitochondrial Creatine Kinase Tyrosine Residues Render Cardioprotection against Hypoxia/Reoxygenation Injury

Objective

Ischemic cardiomyopathy (ICM) is the leading cause of heart failure. Proteomic and genomic studies have demonstrated ischemic preconditioning (IPC) can assert cardioprotection against ICM through mitochondrial function regulation. Considering IPC is conducted in a relatively brief period, regulation of protein expression also occurs very rapidly, highlighting the importance of protein function modulation by post-translational modifications. This study aimed to identify and analyze novel phosphorylated mitochondrial proteins that can be harnessed for therapeutic strategies for preventing ischemia/reperfusion (I/R) injury.

Methods

Sprague-Dawley rat hearts were used in an ex vivo Langendorff system to simulate normal perfusion, I/R, and IPC condition, after which the samples were prepared for phosphoproteomic analysis. Employing human cardiomyocyte AC16 cells, we investigated the cardioprotective role of CKMT2 through overexpression and how site-directed mutagenesis of putative CKMT2 phosphorylation sites (Y159A, Y255A, and Y368A) can affect cardioprotection by measuring CKMT2 protein activity, mitochondrial function and protein expression changes.

Results

The phosphoproteomic analysis revealed dephosphorylation of mitochondrial creatine kinase (CKMT2) during ischemia and I/R, while preserving its phosphorylated state during IPC. CKMT2 overexpression conferred cardioprotection against hypoxia/reoxygenation (H/R) by increasing cell viability and mitochondrial adenosine triphosphate level, preserving mitochondrial membrane potential, and reduced reactive oxygen species (ROS) generation, while phosphomutations, especially in Y368, nullified cardioprotection by significantly reducing cell viability and increasing ROS production during H/R. CKMT2 overexpression increased mitochondrial function by mediating the proliferator-activated receptor γ coactivator-1α/estrogen-related receptor-α pathway, and these effects were mostly inhibited by Y368A mutation.

Conclusion

These results suggest that regulation of quantitative expression and phosphorylation site Y368 of CKMT2 offers a unique mechanism in future ICM therapeutics.

Obesity associated pro-fibrotic protein augments fibrosis in heart

 

Chronic sterile inflammation in visceral fat has causal roles for systemic metabolic disorders in obesity. Inflamed visceral adipose tissue secretes pro-inflammatory adipokines, and this contributes to tissue remodeling under a metabolically stressed condition. Various kinds of white adipokines are broadly studied, however, roles of brown adipose tissue (BAT) derived adipokines (BATokine) remain to be explored. In this project, we tried to characterize pathogenic role of BATokine in obesity related fibrotic disorders, especially focusing on heart failure with preserved ejection fraction (HFpEF). For this purpose, we analyzed two sets of DNA microarray data, and identified an obesity associated pro-fibrotic protein (OAFP) as a possible pathogenic BATokine. Our biobank studies showed OAFP increased in patients with diastolic dysfunction, and E/e' analyzed with cardiac echo increased in direct proportion to circulating OAFP level in humans. We generated dietary obese mice model, and found OAFP increased both in BAT and circulation. We generated a murine systemic or BAT specific OAFP knockout (KO) models, and found that obesity-induced diastolic dysfunction ameliorated in these models. Cardiac fibrosis was also suppressed by genetic depletion of OAFP. We found OAFP increased in circulation in aged humans and mice, and studies in chronologically aged mice showed this molecule increased in BAT with aging. Our results indicate that OAFP is secreted predominantly from BAT, and mediates pathogenic roles by augmenting cardiac fibrosis in dietary obesity or aging. Suppression of OAFP may become a therapy for HFpEF.

Funding Acknowledgement

Type of funding source: None

The crucial roles of coagulation factors in inducing brown adipose tissue dysfunction and systemic metabolic disorder in obesity

 

The prevalence of obesity is increasing worldwide. Obese individuals are predisposed to cardio-metabolic disorders. Brown adipose tissue (BAT) is an active metabolic organ abundant with mitochondria, and studies suggest a potential role of BAT in the maintenance of metabolic health in rodents and humans. Metabolic stress causes BAT dysfunction, but the underlying mechanisms are largely unknown. Coagulation factor Xa (FXa) is critically involved in a coagulation cascade, and it is also known to mediate biological effects by the activation of protease-activated receptor (PAR)-signaling. Accumulating evidence shows that PAR1 contributes to tissue remodeling in cardiovascular system. Analyzing deposited microarray data, we found transcripts for coagulation factors including factor VII (F7), factor X (F10), and PAR1 receptor were increased in BAT from obese mice. Here we show a previously unknown role of FXa-PAR signaling in promoting BAT dysfunction and systemic metabolic disorder in a murine dietary obese model.

Imposing a high fat diet (HFD) on C57BL/6NCr mice led to a marked increase in tissue factor (TF), coagulation factor VII and FXa in BAT. TF-FVIIa (activated form of FVII)-FXa complex is known to activate PAR1, and we found a significant increase in PAR1 expression in BAT upon metabolic stress. Administration of a FXa inhibitor ameliorated BAT whitening, improved thermogenic response and systemic glucose intolerance upon dietary obesity. Fxa inhibition reduced reactive oxygen species (ROS) level in BAT. In contrast, administration of warfarin did not show any phenotype in BAT. BAT specific TF and PAR1 over-expression model showed significant whitening of this tissue, which was associated with systemic glucose intolerance. We generated BAT specific PAR1 KO mice. BAT-PAR1 KO mice exhibited re-browning of BAT along with reduced ROS level in this tissue. In BAT-PAR1 KO mice, glucose intolerance and thermogenic response under a metabolically stressed condition were ameliorated. In differentiated brown adipocytes, FXa markedly increased mitochondrial ROS and reduced mitochondrial membrane potential. Inhibition of PAR1 ameliorated FXa-induced mitochondrial ROS production and reduction in membrane potential. We also found that plasma FXa level did not increase in obese mice as well as in obese individuals. These results suggest the previously unknown role of coagulation systems in promoting BAT dysfunction, leading to systemic metabolic disorders. Maintenance of BAT homeostasis through the suppression of FXa-PAR1 signaling would become a new therapeutic target for obesity and diabetes.

Funding Acknowledgement

Type of funding source: None

Placebo-Controlled, Double-Blind Study of Empagliflozin (EMPA) and Implantable Cardioverter-Defibrillator (EMPA-ICD) in Patients with Type 2 Diabetes (T2DM): Rationale and Design

INTRODUCTION

Type 2 diabetes (T2DM) is associated with cardiovascular death, including sudden cardiac death due to arrhythmias. Patients with an implantable cardioverter-defibrillator (ICD) are also at high risk of developing a clinically significant ventricular arrhythmia. It has been reported that sodium-glucose cotransporter 2 (SGLT2) inhibitors can reduce cardiovascular deaths; however, the physiological mechanisms of this remain unclear. It is, however, well known that SGLT2 inhibitors increase blood ketone bodies, which have been suggested to have sympatho-suppressive effects. Empagliflozin (EMPA) is an SGLT2 inhibitor. The current clinical trial titled "Placebo-controlled, double-blind study of empagliflozin (EMPA) and implantable cardioverter-defibrillator (EMPA-ICD) in patients with type 2 diabetes (T2DM)" was designed to investigate the antiarrhythmic effects of EMPA.

METHODS

The EMPA-ICD study is a prospective, multicenter, placebo-controlled, double-blind, randomized, investigator-initiated clinical trial currently in progress. A total of 210 patients with T2DM (hemoglobin A1c 6.5-10.0%) will be randomized (1:1) to receive once-daily placebo or EMPA, 10 mg, for 24 weeks. The primary endpoint is the number of clinically significant ventricular arrhythmias for 24 weeks before and 24 weeks after study drug administration, as documented by the ICD. The secondary endpoints of the study are the change from baseline concentrations in blood ketone and catecholamine 24 weeks after drug treatment.

CONCLUSION

The EMPA-ICD study is the first clinical trial to assess the effect of an SGLT2 inhibitor on clinically significant ventricular arrhythmias in patients with T2DM and an ICD.

TRIAL REGISTRATION

Unique trial number, jRCTs031180120 ( https://jrct.niph.go.jp/latest-detail/jRCTs031180120 ).

Elimination of senescent cells targeting Senescence associated glycoprotein (SAGP) improved the ageing-associated diseases and extended the lifespan

 

Cellular senescence entails an irreversible growth arrest and a pro-inflammatory secretory phenotype, which contributes to aging-associated disorders such as atherosclerosis and diabetes, however, underlying mechanisms are largely unknown. In this study, we identified a novel protein, senescence-associated glycoprotein (SAGP), as a biomarker of cellular senescence and we also found that elimination of senescent cells targeting SAGP attenuated aging-associated disorders such as atherosclerosis, diabetes and frailty.

First, we identified that SAGP as a senescent marker by microarray analysis of senescent human endothelial cells compared with young endothelial cells. The expression of SAGP was significantly increased in the aorta of chronological aging mice and ApoE-knockout mice. Then we measured SAGP expression in the patients registered in our hospital and found that mean SAGP expression was significantly higher in patients with atherosclerotic diseases compared to patients without atherosclerotic diseases. These data suggest that SAGP would become the novel marker of cellular senescence and/or aging-associated disorders.

We found SAGP co-localized with lysosome and bound to V-ATPase, proton pump in the acid organelles such as lysosome. The electron microscopy analysis revealed that the dysfunctional lysosomes were accumulated in SAGP knockdown endothelial cell. The genetic deletion of SAGP resulted in the increase of lysosomal pH and the suppression of mitochondrial autophagy, mitophagy. And this associated with the high level of mitochondrial reactive oxygen species (ROS) and promoted premature senescence in human endothelial cells. These data suggest that SAGP was induced by the lysosomal stress in the senescent cells to protects senescent cells by maintaining the lysosomal homeostasis.

Recently, it is reported that elimination of senescent cells (senolysis) reversibly improved pathological aging phenotypes and also extended the lifespan. We established senolytic therapy targeting SAGP. We generated SAGP-DTR (diphtheria toxin receptor) transgenic mice, in which we could eliminate the SAGP- positive senescent cells using DT (diphtheria toxin). We found elimination of SAGP positive senescent cells significantly reduced the atherosclerotic plaque burden in the aorta of ApoE-KO mice and improved the glucose metabolism of dietary obese mice, indicating that SAGP could be a useful target for senolytic therapy. For clinical implication, we then developed a cytotoxic vaccine targeting SAGP. Treatment with SAGP vaccine successfully eliminated SAGP positive senescent cells and attenuated atherosclerosis and metabolic dysfunction. Surprisingly, administration of SAGP vaccine to Zmpste24-KO mice, premature aging mice, extended the lifespan. These data indicate that targeting SAGP-positive cells could be a novel strategy for senolytic therapy.

Effect of SAGP vaccine

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Scientific Research by Japan Society for the Promotion of Science (JSPS)

Cardiac mitofusin-1 is declined in non-responding patients with idiopathic dilated cardiomyopathy

Background/Introduction

Mitochondria are dynamic regulators of cellular metabolism and homeostasis. The dysfunction of mitochondria has long been considered a major contributor to aging and age-related diseases. The prognosis of severe heart failure is still unacceptably poor and it is urgent to establish new therapies for this critical condition. Some patients with heart failure do not respond to established multidisciplinary treatment and they are classified as “non-responders”. The outcome is especially poor for non-responders, and underlying mechanisms are largely unknown.

Purpose

Studies indicate mitochondrial dysfunction has causal roles for metabolic remodeling in the failing heart, but underlying mechanisms remain to be explored. This study tried to elucidate the role of Mitofusin-1 in a failing heart.

Methods

We examined twenty-two heart failure patients who underwent endomyocardial biopsy of intraventricular septum. Patients were classified as non-responders when their left-ventricular (LV) ejection fraction did not show more than 10% improvement at remote phase after biopsy. Fourteen patients were classified as responders, and eight as non-responders. Electron microscopy, quantitative PCR, and immunofluorescence studies were performed to explore the biological processes or molecules involved in failure to respond. In addition to studies with cardiac tissue specific knockout mice, we also conducted functional in-vitro studies with neonatal rat ventricular myocytes.

Results

Twenty-two patients with IDCM who underwent endomyocardial biopsy were enrolled in this study, including 14 responders and 8 non-responders. Transmission electron microscopy (EM) showed a significant reduction in mitochondrial size in cardiomyocytes of non-responders compared to responders. Quantitative PCR revealed that transcript of mitochondrial fusion protein, Mitofusin-1, was significantly reduced in non-responders. Studies with neonatal rat ventricular myocytes (NRVMs) indicated that the beta-1 adrenergic receptor-mediated signaling pathway negatively regulates Mitofusin-1 expression. Suppression of Mitofusin-1 resulted in a significant reduction in mitochondrial respiration of NRVMs. We generated left ventricular pressure overload model with thoracic aortic constriction (TAC) in cardiac specific Mitofusin-1 knockout model (c-Mfn1 KO). Systolic function was reduced in c-Mfn1 KO mice, and EM study showed an increase in dysfunctional mitochondria in the KO group subjected to TAC.

Conclusions

Mitofusin-1 becomes a biomarker for non-responders with heart failure. In addition, our results suggest that therapies targeting mitochondrial dynamics and homeostasis would become next generation therapy for severe heart failure patients.

Funding Acknowledgement

Type of funding source: None

A novel senolytic drug, seno-7284 ameliorates aging phenotype and age-related cardiometabolic diseases

Background

Cellular senescence occurs as a result of various genotoxic stresses and it plays a pivotal role in aging and age-related disorders. Recently, it was shown that elimination of senescent cells, so-called “senolysis” has the potential to become a promising novel therapy for age-related disorders in several mice models including cardiovascular diseases. However, there is no senolytic drug available in clinical settings currently.

Purpose

The present study was aimed to identify a novel senolytic reagent effective for cardiometabolic disease among compounds already available in clinical settings. Here we demonstrate that a compound called “seno-7284” exhibits senolytic effect in murine models of type 2 diabetes, atherosclerosis, progeroid and chronological aging.

Methods

We generated diet-induced obesity/diabetic mice model by imposing high-fat diet from 4-week-old for two months, atherosclerosis mice model by imposing western diet to ApoE homozygous knockout mice (ApoE-KO mice) from 4-week-old for 3 months. We administered seno-7284 mixed in the diet (0.03% w/w) to each mouse model for 1, 2 or 4 weeks. For the analysis, we carried out some physiological examinations including glucose tolerance test (GTT) and insulin tolerance test (ITT), then harvested tissue samples and took them to molecular biological analysis including real-time PCR, western blotting, RNA-sequence, etc. We also generated Zmpste24 homozygous knockout mice (Zmpste24-KO mice) as a progeroid mice model to measure their lifespan. Seno-7284 was administered to Zmpste24-KO mice from 12-week-old to the end of life. We also administrated seno-7284 to chronological aged mice at 1-year-old for 20 weeks and their physical function was examined with rotarod running test and hand-grip test.

Results

Seno-7284 reduced the accumulation of senescent cells in visceral adipose tissue of dietary obese mice as senescence-associated beta-galactosidase (SA-beta-gal) staining exhibits (Figure 1a). This effect results in ameliorating insulin tolerance (Figure 1b) and adipose tissue inflammation after 4-week administration of seno-7284. We also found administrating Seno-7284 for two weeks also reduced the accumulation of senescent cells in the atherosclerotic lesion in the aorta of ApoE-KO mice (Figure 1c) and inhibited advancing atherosclerosis (Figure 1d). Surprisingly, seno-7284 significantly improved the lifespan of Zmpste24 KO mice (Figure 1e). Seno-7284 also improved the physical function of chronologically aged mice by administrating it from 1-year-old for 20 weeks (Figure 1f). In-vitro studies didn't exhibit seno-7284 kills senescent cells directly, but further analysis including RNA-seq or metabolomic analysis speculated that seno-7284 stimulates endogenous senolytic function of NK-cells and CD8+ T-cells.

Conclusion

Our results indicate that seno-7284 would become a promising senolytic drug that exhibits novel therapeutic machinery for aging and age-related cardiometabolic diseases.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Scientific Research (KAKENHI) C, Niigata University Tsukada medical research grant

Circulating pro fibrotic protein promotes fibrosis in liver

Background/Introduction

Non-alcoholic steatohepatitis (NASH), driven by the obesity epidemic, has become the most common form of liver disease. Inflamed visceral adipose tissue secretes pro-inflammatory adipokines that are causal for systemic metabolic disorders. Role of adipokines in NASH, especially those from brown adipose tissues (BATokine) remain unclear.

Purpose

To show the pathogenic role of BATokine in NASH.

Methods

To identify and characterize the pathological roles of pro-fibrotic BATokine, we generated a murine obese NASH model by imposing a high fat diet in C57BL6/NCr mice, and murine systemic or BAT specific knockout (KO) models. We also conducted functional in-vitro studies with differentiated brown adipocytes.

Results

Analyzing two sets of DNA micro array data with bioinformatics, we identified a secreted form pro-fibrotic protein (sPFP) expressed in dysfunctional brown adipose tissues (BAT) in mice. Testing our biobank samples, we found this protein increased in plasma of NASH patients. We generated a murine obese NASH model by imposing a high fat diet in C57BL6/NCr mice for 9–10 months since 4 weeks of age, and found that sPFP is produced predominantly by BAT. In this model, we also found that sPFP increased in plasma. We generated a murine systemic or BAT specific sPFP knockout (KO) models and found that liver fibrosis ameliorated in these models. We also suppressed circulating sPFP with a peptide vaccine targeting this molecule, and found that sPFP vaccination therapy inhibited liver fibrosis. Next, we generated sPFP gain of function (GOF) model by the administration of plasmid encoding sPFP into skeletal muscle. Liver fibrosis augmented in sPFP-GOF model, and these results suggested that sPFP has causal role for the progression of fibrotic response in liver. In vitro studies with differentiated brown adipocytes showed that metabolic stress increased c-Fos in nuclear, and this was causal for an increase in sPFP level.

Conclusions

Our results suggest that one of the BATokines, sPFP, contributes for the progression of fibrotic responses in obese-NASH model. Inhibition of sPFP may become a therapy for NASH or obesity related fibrotic disorders.

Funding Acknowledgement

Type of funding source: None

BH4 activates CaMKK2 and rescues the cardiomyopathic phenotype in rodent models of diabetes

Diabetic cardiomyopathy (DCM) is a major cause of mortality/morbidity in diabetes mellitus patients. Although tetrahydrobiopterin (BH4) shows therapeutic potential as an endogenous cardiovascular target, its effect on myocardial cells and mitochondria in DCM and the underlying mechanisms remain unknown. Here, we determined the involvement of BH4 deficiency in DCM and the therapeutic potential of BH4 supplementation in a rodent DCM model. We observed a decreased BH4:total biopterin ratio in heart and mitochondria accompanied by cardiac remodeling, lower cardiac contractility, and mitochondrial dysfunction. Prolonged BH4 supplementation improved cardiac function, corrected morphological abnormalities in cardiac muscle, and increased mitochondrial activity. Proteomics analysis revealed oxidative phosphorylation (OXPHOS) as the BH4-targeted biological pathway in diabetic hearts as well as BH4-mediated rescue of down-regulated peroxisome proliferator-activated receptor-γ coactivator 1-α (PGC-1α) signaling as a key modulator of OXPHOS and mitochondrial biogenesis. Mechanistically, BH4 bound to calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2) and activated downstream AMP-activated protein kinase/cAMP response element binding protein/PGC-1α signaling to rescue mitochondrial and cardiac dysfunction in DCM. These results suggest BH4 as a novel endogenous activator of CaMKK2.

Abstract 245: Cardiac Mitofusin-1 is Suppressed in Non-responding Patients With Heart Failure

Background/Introduction: Mitochondria are dynamic regulators of cellular metabolism and homeostasis. The dysfunction of mitochondria has long been considered a major contributor to aging and age-related diseases. The prognosis of severe heart failure is still unacceptably poor and it is urgent to establish new therapies for this critical condition. Some patients with heart failure do not respond to established multidisciplinary treatment and they are classified as “non-responders”. The outcome is especially poor for non-responders, and underlying mechanisms are largely unknown.

Purpose: Studies indicate mitochondrial dysfunction has causal roles for metabolic remodeling in the failing heart, but underlying mechanisms remain to be explored. This study tried to elucidate the role of Mitofusin-1 in a failing heart.

Methods: We examined twenty-two heart failure patients who underwent endomyocardial biopsy of intraventricular septum. Patients were classified as non-responders when their left-ventricular (LV) ejection fraction did not show more than 10% improvement at remote phase after biopsy. Fourteen patients were classified as responders, and eight as non-responders. Electron microscopy, quantitative PCR, and immunofluorescence studies were performed to explore the biological processes or molecules involved in failure to respond. In addition to studies with cardiac tissue specific knockout mice, we also conducted functional in-vitro studies with neonatal rat ventricular myocytes.

Results: Twenty-two patients with IDCM who underwent endomyocardial biopsy were enrolled in this study, including 14 responders and 8 non-responders. Transmission electron microscopy (EM) showed a significant reduction in mitochondrial size in cardiomyocytes of non-responders compared to responders. Quantitative PCR revealed that transcript of mitochondrial fusion protein, Mitofusin-1, was significantly reduced in non-responders. Studies with neonatal rat ventricular myocytes (NRVMs) indicated that the beta-1 adrenergic receptor-mediated signaling pathway induced microRNA-140 3p and 5p, which is negatively regulated Mitofusin-1 expression. Suppression of Mitofusin-1 resulted in a significant reduction in mitochondrial respiration of NRVMs. We generated left ventricular pressure overload model with thoracic aortic constriction (TAC) in cardiac specific Mitofusin-1 knockout model (c-Mfn1 KO). Systolic function was reduced in c-Mfn1 KO mice, and EM study showed an increase in dysfunctional mitochondria in the KO group subjected to TAC.

Conclusions: Mitofusin-1 becomes a biomarker for non-responders with heart failure. In addition, our results suggest that therapies targeting mitochondrial dynamics and homeostasis would become next generation therapy for severe heart failure patients.

Cellular Senescence in Arterial Diseases

Cell-proliferation potency is limited, as cells cannot proceed through the cell cycle continually. Instead, they eventually show an irreversible arrest of proliferation, commonly referred to as cellular senescence. Following the initial discovery of this phenomenon by Hayflick et al., studies have indicated that cells are also destined to undergo aging. In addition to the irreversible termination of proliferation, senescent cells are characterized by a flattened and enlarged morphology. Senescent cells become pro-inflammatory and contribute to the initiation and maintenance of sustained chronic sterile inflammation. Aging is associated with the accumulation of senescent cells in the cardiovascular system, and in general these cells are considered to be pathogenic because they mediate vascular remodeling. Recently, genetic and pharmacological approaches have enabled researchers to eliminate senescent cells both in vitro and in vivo. The term “senolysis” is now used to refer to the depletion of senescent cells, and evidence indicates that senolysis contributes to the reversal of age-related pathogenic phenotypes without the risk of tumorigenesis. The concept of senolysis has opened new avenues in research on aging, and senolysis may be a promising therapeutic approach for combating age-related disorders, including arterial diseases.

Relation of Poor Nutritional Status to Mild Cognitive Impairment in Patients with Coronary Artery Disease

OBJECTIVES

Nutritional status affects cerebral circulation and cognitive function. More attention needs to be paid to nutritional status in coronary artery disease (CAD) patients, yet the relation between nutritional status or dietary intake (DI) and cognitive function or mild cognitive impairment (MCI) in CAD patients remain unclear. Thus, we examined the following relations: 1) that between nutritional status and cognitive function, and MCI and 2) that between DI and cognitive function, and MCI.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a cross-sectional study of 208 patients with CAD but without dementia.

MEASUREMENTS

MCI was estimated with the Japanese version of the Montreal Cognitive Assessment (MoCA-J). Nutritional status was assessed by the Geriatric Nutritional Risk Index (GNRI), and DI was assessed by total energy intake per day. We investigated the relation between nutritional status or DI and cognitive function by Pearson correlation analysis, and that between nutritional status or DI and MCI by multivariable logistic regression analysis.

RESULTS

The GNRI and DI were positively associated with the MoCA-J score (r = 0.23, p < 0.001, and r = 0.24, p < 0.001, respectively), and both were independently associated with MCI in the multivariable logistic regression analysis (odds ratio, 0.96; p = 0.045, and odds ratio, 0.998; p = 0.020, respectively).

CONCLUSIONS

Poor nutritional status and low DI were found to be significantly associated with cognitive function and MCI in CAD patients. Our findings regarding nutritional status and DI might be useful for clinicians to prevent or intervene in the early cognitive decline of inpatients with CAD.

Tetrahydrobiopterin enhances mitochondrial biogenesis and cardiac contractility via stimulation of PGC1α signaling

Tetrahydrobiopterin (BH4) shows therapeutic potential as an endogenous target in cardiovascular diseases. Although it is involved in cardiovascular metabolism and mitochondrial biology, its mechanisms of action are unclear. We investigated how BH4 regulates cardiovascular metabolism using an unbiased multiple proteomics approach with a sepiapterin reductase knock-out (Spr-/-) mouse as a model of BH4 deficiency. Spr-/- mice exhibited a shortened life span, cardiac contractile dysfunction, and morphological changes. Multiple proteomics and systems-based data-integrative analyses showed that BH4 deficiency altered cardiac mitochondrial oxidative phosphorylation. Along with decreased transcription of major mitochondrial biogenesis regulatory genes, including Ppargc1a, Ppara, Esrra, and Tfam, Spr-/- mice exhibited lower mitochondrial mass and severe oxidative phosphorylation defects. Exogenous BH4 supplementation, but not nitric oxide supplementation or inhibition, rescued these cardiac and mitochondrial defects. BH4 supplementation also recovered mRNA and protein levels of PGC1α and its target proteins involved in mitochondrial biogenesis (mtTFA and ERRα), antioxidation (Prx3 and SOD2), and fatty acid utilization (CD36 and CPTI-M) in Spr-/- hearts. These results indicate that BH4-activated transcription of PGC1α regulates cardiac energy metabolism independently of nitric oxide and suggests that BH4 has therapeutic potential for cardiovascular diseases involving mitochondrial dysfunction.

5892Elimination of cells expressing Senescence associated glycoprotein (SAGP) attenuates the atherosclerotic diseases

Cellular senescence is defined as a state of irreversible growth arrest and is accompanied by changes of both cell morphology and gene expression. Although accumulation of senescent vascular endothelial cells impair the vessel homeostasis and promote atherosclerotic diseases, underlying mechanisms are largely unknown. In this study, we identified a novel protein, senescence-associated glycoprotein (SAGP), as a biomarker of cellular senescence and we found modulation of SAGP or elimination of senescent cells targeting SAGP would become a novel therapy for atherosclerotic diseases.

We found that SAGP expression was significantly increased in human endothelial cells undergoing replicative senescence compared with young endothelial cells. We also found SAGP expression in aorta was significantly increased both in chronological aging mice or ApoE knockout mice. Furthermore, we measured SAGP expression in patients registered in our hospital and found that mean SAGP expression was significantly higher in patients with atherosclerotic diseases compared to patients without atherosclerotic diseases.These data suggest that SAGP would become a novel cellular senescence and/or atherosclerotic disease marker.

Genetic deletion of SAGP resulted in high level of mitochondrial reactive oxygen species (ROS) and promoted premature senescence in human endothelial cells. And this associated with suppression of mitochondrial autophagy, mitophagy. We found SAGP co-localized with lysosome by immunocytochemistry. In addition, the electron microscopy analysis revealed that the dysfunctional lysosomes were accumulated in SAGP knockdown endothelial cell, suggesting that SAGP maintain lysosomal homeostasis.

Next, wegenerated ApoE-KO/ SAGP overexpression mice and found that atherosclerotic plaque burden was attenuated in these double-transgenic mice. In contrast, SAGP/ApoE double knockout mice showed progression in atherosclerosis. These data suggest that modulation of SAGPwould become a new therapeutic target for atherosclerotic diseases.

SAGP vaccine

Recently, it is reported that elimination of senescent cells (senolysis) reversibly improved pathological aging phenotypes and also extended the lifespan. We have taken another approach for atherosclerotic diseases, senolytic therapy targeting SAGP. We generated SAGP-DTR (diphtheria toxin receptor) transgenic mice, in which we could eliminate the SAGP- positive senescent cells using DT (diphtheria toxin). We found elimination of SAGP positive senescent cells significantly reduced the atherosclerotic plaque burden, indicating that SAGP would become a useful target for senolytic therapy. We then developed a cytotoxic vaccine targeting SAGP. Treatment with SAGP vaccine successfully eliminated SAGP positive senescent cells. Administration of SAGP vaccine to ApoE-KO mice significantly reduced atherogenesis. These data indicate that targeting SAGP-positive cells could become a strategy for senolytic therapy.

P3496Empagliflozin improves cardiac function through the increased production of acetylcarnitine in a murine non-diabetic heart failure model

Background

Empagliflozin is a renal sodium glucose transporter 2 (SGLT2) inhibitor, thereby mediates its anti-diabetic effect via excretion of glucose into urine. EMPA-REG OUTCOME study, the first big randomized control trial of empagliflozin have shown significant reduction of mortality and hospitalization due to heart failure in diabetic patients. This trial hasn't only had a huge impact to cardiovascular field, but also raised a number of questions about underlying mechanisms. It is also uncertain about the efficacy of empagliflozin in non-diabetic heart failure. In this study, we aimed to elucidate the biological effects and its underling mechanism of empagliflozin in a murine non-diabetic heart failure model.

Methods

We generated a heart failure murine model due to left ventricular (LV) pressure overload by performing transverse aortic constriction (TAC) operation to C57BL/6NCr mice. Two weeks after TAC operation we started empagliflozin administration mixed with diet at the ratio of 0.03% w/w. LV function was measured with echocardiography after administration of empagliflozin for two weeks (four weeks after TAC operation) and compared to a littermate control (no treatment) group. Then, heart samples were collected and subjected to further studies including metabolomic analysis. In-vitro studies including Seahorse Extracellular Flux Analyzer were also conducted with differentiated C2C12 cells and neonatal rat ventricular myocytes (NRVM).

Results

We found that empagliflozin treatment (Empa) significantly ameliorated LV systolic dysfunction induced by TAC compared to control group (Con) (figure.A) while heart weight/body weight ratio wasn't reduced. To explore key metabolites that can contribute to improvement of LV function, we conducted metabolomic analysis and found that empagliflozin significantly increased plasma acetylcarnitine level both in sham and TAC groups (figure.B). Previous studies have shown that acetylcarnitine acts as a substrate of acetyl CoA to fuel tricarboxylic acid cycle, and we tested the efficacy of acetylcarnitine for mitochondrial respiration capacity in differentiated C2C12 cells with Seahorse Extracellular Flux Analyzer. This analysis revealed that administration of acetylcarnitine resulted in a significant increase of oxygen consumption reflected by enhancing mitochondrial respiration. Similary, acetylcarnitine also markedly ameliorated impairment of mitochondrial respiration induced by isoproterenol in NRVM.

Conclusion

Our results indicated that empagliflozin has cardioprotective effect in murine heart failure model by enhancing mitochondrial respiration through the increased production of acetylcarnitine. We provide new evidence that empagliflozin would become a promising therapeutic agent to heart failure without diabetes.

P2591Circulating pro fibrotic protein promotes fibrosis in liver and heart

Analyzing two sets of DNA micro array data with bioinformatics, we identified a secreted form pro-fibrotic protein (sPFP) expressed in dysfunctional brown adipose tissue (BAT) in mice. Testing our biobank samples, we found this protein increased in plasma of non-alcoholic steatohepatitis (NASH) patients or aged individuals. We generated a murine obese NASH model by imposing a high fat diet in C57BL/6NCr mice for 9–10 months since 4 weeks of age, and found that sPFP is produced predominantly by BAT. In this model, we also found that sPFP increased in plasma. We generated a murine systemic sPFP knockout (KO) model and found that liver fibrosis ameliorated in sPFP-KO model. We also suppressed circulating sPFP with a peptide vaccine targeting this molecule, and found that sPFP vaccination therapy inhibited liver fibrosis. Next, we generated sPFP gain of function (GOF) model by the administration of plasmid encoding sPFP into skeletal muscle. Liver fibrosis augmented in sPFP-GOF model, and these results suggested that sPFP has causal role for the progression of fibrotic response in liver. In the obese NASH model, we found that cardiac fibrosis also developed and it ameliorated in sPFP-KO model, indicating that sPFP may have pathological roles for heart failure with preserved ejection fraction (HFpEF) related with age-related disorders. In addition to an increase in circulating sPFP in aged individuals, we found that sPFP increased in BAT of chronological aged mice model. In vitro studies with differentiated brown adipocytes showed that c-Fos upregulated sPFP in transcript level. Our results suggest that sPFP contributes for the progression of fibrotic responses in obese or aged models. Inhibition of sPFP may become a therapy for NASH or HFpEF.

P1613Brown adipose tissue dysfunction has a critical role for the development of heart failure in murine pressure overload model

Prognosis of severe heart failure is unacceptably high, and it is our urgent task to find therapies for this critical condition. It has been reported that low body temperature predicts poor clinical outcomes in patients with heart failure, however, underlying mechanisms and pathological implications are largely unknown. Brown adipose tissue (BAT) was initially characterized as a heat generating organ, and studies suggest that BAT has crucial roles for the maintenance of systemic metabolic health. Here we show that BAT dysfunction develops in a murine thoracic aortic constriction (TAC) model, and has a causal role for promoting pathologies in failing heart. TAC operation led to a significant reduction both in intraperitoneal and subcutaneous temperature. TUNEL-positive cells significantly increased in BAT during left ventricular (LV)-pressure overload, and in-vitro studies with differentiated brown adipocytes suggested that the chronic activation of adrenergic signaling promotes apoptosis in these cells. Gain of BAT function model, generated with BAT implantation into peritoneal cavity, improved thermogenesis and ameliorated cardiac dysfunction in TAC. In contrast, genetic model of BAT dysfunction promoted cardiac dysfunction. Metabolomic analyses showed that BAT dysfunction led to an increase of oxidized choline that promoted metabolic dysfunction in the failing heart. Electron microscope study showed that oxidized choline induced mitochondrial dysfunction in vitro as well as in vivo settings. Extracellular flux analyzerindicated that oxidized choline suppresses oxidative phosphorylation in mitochondria. We found that dilated cardiomyopathy patients have lower body temperature, and confirmed by metabolomic study that both choline and oxidized choline are increased in circulation. Maintenance of BAT homeostasis and suppression of oxidized choline would become a novel therapeutic target for heart failure.

Abstract 863: Pathological Roles of Senometabolites in Cardiovascular Disorders

Mechanisms contributing for the synchronization of aging are yet to be defined. Here, we define “senometabolite” as circulating metabolites having causal roles for the synchronization and progression of aging. Analyzing metabolomic studies in coronary plaque corrected with directional coronary atherectomy (DCA), we found that hydroxyl-metabolite significantly increased in patients with unstable angina compared with stable angina. We generated murine diet induced obese model and found this metabolite increased in aorta and plasma. Administration of this metabolite into human umbilical vein endothelial cells (HUVECs) induced cellular senescence, and immunofluorescence study showed that putative transhydrogenase increased in patients with atherosclerotic disorders. We did metabolomics studies in aged individuals or patients with heart failure and identified another metabolite, oxidized choline, increased under these conditions compared to respective controls. We generated murine left ventricular (LV) pressure overload model and found that oxidized choline increased both in plasma and failing heart. Administration of oxidized choline deteriorated cardiac function, in contrast, genetic model showed suppression of this metabolite ameliorated systolic dysfunction in LV pressure overload model. Proteomic study showed that oxidized choline reduced the expression of cytochrome c oxidase subunit1, and metabolomics study showed that both ATP and phosphocreatine level significantly reduced in cardiac tissues of wild type mice administrated with this metabolite. Administration of oxidized choline also reduced muscle strength, induced fibrosis in skeletal muscle, and electron microscopy showed an increase in dysfunctional mitochondria both in the heart and skeletal muscle. In aged wild type mice, metabolomic study showed oxidized choline increased in plasma. Aging process is still mysterious and continues to be an interesting topic to be explored. Our findings indicate that circulating senometabolites contribute for the progression of pathologies in age related disorders.

Abstract 804: Elimination of Cells Expressing Senescence Associated Glycoprotein Attenuates Theatherosclerotic Diseases

Although accumulation of senescent vascular endothelial cells impairs the vessel homeostasis and promote atherosclerotic diseases, underlying mechanisms are largely unknown. We found that Senescence associated glycoprotein (SAGP) expression was significantly increased in human endothelial cells undergoing replicative senescence. SAGP expression in aorta was significantly increased in Apo-E knockout mice. Furthermore, mean SAGP expression was significantly higher in the leukocytes of the patients with atherosclerotic diseases.These data suggest that SAGP would become the novel cellular senescence and/or atherosclerotic disease marker. The genetic deletion of SAGP resulted in high level of mitochondrial reactive oxygen species (ROS) and promoted premature senescence in human endothelial cells. And this associated with suppression of mitochondrial autophagy, mitophagy, suggesting that SAGP protect cells from ROS by inducing mitophagy. Thus, wegenerated ApoE-KO / SAGP gain-of-function transgenic mice and found that atherosclerotic plaque burden was attenuated in these transgenic mice. In contrast, in SAGP / ApoE double knockout mice atherosclerosis were impaired. These data suggest that modulation of SAGPwould become a new therapeutic target for atherosclerotic diseases.Recently, it is reported that elimination of senescent cells (senolysis) reversibly improved pathological aging phenotypes. We generated SAGP-DTR (diphtheria toxin receptor) transgenic mice,inducible elimination of SAGP positive senescent cells upon administration of diphtheria toxin. Elimination of SAGP expressing cells significantly reduced the atherosclerotic plaque burden. Furthermore, we developed a cytotoxic vaccine targeting SAGP. Administration of SAGP vaccine to ApoE-KO mice significantly reduced atherogenesis. These data indicate that targeting SAGP-positive cells could be a strategy for senolytic therapy.

Abstract 852: The Pathological Role of Coagulation Factors in Promoting Brown Adipose Tissue Dysfunction and Systemic Metabolic Disorder in Obesity

Obese individuals are predisposed to cardio-metabolic disorders. Brown adipose tissue (BAT) is an active metabolic organ abundant with mitochondria, and studies suggest a potential role of BAT in the maintenance of metabolic health in rodents and humans. Metabolic stress causes BAT dysfunction, but the underlying mechanisms are largely unknown. Coagulation factor Xa (FXa) is critically involved in a coagulation cascade, and it is also known to mediate biological effects by the activation of protease-activated receptor (PAR)-signaling. Accumulating evidence shows that PAR1 contributes to tissue remodeling in cardiovascular system. Here we show a previously unknown role of FXa-PAR signaling in promoting BAT dysfunction and systemic metabolic disorder in a murine dietary obese model.

Imposing a high fat diet (HFD) on C57BL/6NCr mice led to a marked increase in tissue factor (TF), coagulation factor VII and FXa in BAT. TF-FVIIa (activated form of FVII)-FXa complex is known to activate PAR1, and we found a significant increase in PAR1 expression in BAT upon metabolic stress. Administration of a FXa inhibitor ameliorated BAT whitening, improved thermogenic response and systemic glucose intolerance upon dietary obesity. In contrast, administration of warfarin did not show any phenotype in BAT. BAT specific TF and PAR1 over-expression model showed significant whitening of this tissue, which was associated with systemic glucose intolerance. BAT specific PAR1 KO mice improved glucose intolerance and thermogenic response under a metabolically stressed condition. In differentiated brown adipocytes, FXa markedly increased mitochondrial reactive oxygen species (ROS) and reduced mitochondrial membrane potential. Inhibition of PAR1 ameliorated FXa-induced mitochondrial ROS production and reduction in membrane potential. We also found that plasma FXa level did not increase in obese mice as well as in obese individuals. These results suggest the previously unknown role of coagulation systems in promoting BAT dysfunction, leading to systemic metabolic disorders. Maintenance of BAT homeostasis through the suppression of FXa-PAR1 signaling would become a new therapeutic target for obesity and diabetes

Abstract 752: A Novel Senolytic Drug, Seno-7284 Ameliorates Aging and Age-related Cardiometabolic Disorders

Accumulation of senescent cells is promoted in various organs as aging, and it also contributes to the progression of age-related disorders. Recent reports have demonstrated the elimination of senescent cells, so-called "senolysis" ameliorated various age-related disorders including cardiovascular diseases. However, there is currently no senolytic drug available in clinical settings. Here, we found a novel senolytic drug (termed “seno-7284”) from those already used in clinical setting and it exhibited senolytic effect in murine models of type 2 diabetes, atherosclerosis and progeroid aging. Conducting senescence-associated beta-galactosidase staining(SA-beta gal), we found that administrating seno-7284 for one week significantly reduced the accumulation of senescent cells in viscerala dipose tissue of diabetic mice induced by fed high-fat diet(Figure). This drug also ameliorated systemic glucose metabolism and adipose tissue inflammation without a reduction of body weight. Further analysis including RNA-seq analysis suggested seno-7284 stimulates the endogenous senolytic function of NK cells and CD8+ T cells via the Cxcl9-Cxcr3 axis. We also found administrating seno-7284 for two weeks also reduced the accumulation of senescent cells and atherosclerotic lesions in the aorta of western-diet-fed ApoE knock out mice. Surprisingly, this drug significantly improved the lifespan of Zmpste24 KO progeroid aging mice. Correctively, our results indicate that seno-7284 mediates its senolytic effect through the recruitment of lymphocytes. Senolytics would become a promising therapy for aging and age-related cardiometabolic disorders.

Abstract 529: Circulating Pro Fibrotic Protein Promotes Fibrosis in Liver and Heart

Analyzing two sets of DNA micro array data with bioinformatics, we identified a secreted form pro-fibrotic protein (sPFP) expressed in dysfunctional brown adipose tissue (BAT) in mice. Testing our biobank samples, we found this protein increased in plasma of non-alcoholic steatohepatitis (NASH) patients or aged individuals. We generated a murine obese NASH model by imposing a high fat diet in C57BL/6NCr mice for 9-10 months since 4 weeks of age, and found that sPFP is produced predominantly by BAT. In this model, we also found that sPFP increased in plasma. We generated a murine systemic sPFP knockout (KO) model and found that liver fibrosis ameliorated in sPFP-KO model. We also suppressed circulating sPFP with a peptide vaccine targeting this molecule, and found that sPFP vaccination therapy inhibited liver fibrosis. Next, we generated sPFP gain of function (GOF) model by the administration of plasmid encoding sPFP into skeletal muscle. Liver fibrosis augmented in sPFP-GOF model, and these results suggested that sPFP has causal role for the progression of fibrotic response in liver. In the obese NASH model, we found that cardiac fibrosis also developed and it ameliorated in sPFP-KO model, indicating that sPFP may have pathological roles for heart failure with preserved ejection fraction (HFpEF) related with age-related disorders. In addition to an increase in circulating sPFP in aged individuals, we found that sPFP increased in BAT of chronological aged mice model. In vitro studies with differentiated brown adipocytes showed that c-Fos upregulated sPFP in transcript level. Our results suggest that sPFP contributes for the progression of fibrotic responses in obese or aged models. Inhibition of sPFP may become a therapy for NASH or HFpEF.

Cellular senescence in cardiac diseases

Replicative capacity of somatic cells is limited. It indicates that aging also develops at the cellular level, and this is described as "cellular senescence". Senescent cells become flattened, enlarged, and irreversibly lose capacity for proliferation. Lack of specific and conclusive markers for cellular senescence makes it difficult to comprehensively define and understand this biological process especially in vivo. Molecules including p53, p21, p16^Ink4a, p38MAPK, and γH2AX, telomere attrition, enhanced signals for SA-β-gal, etc. are widely used to detect senescent cells, but these are indirect indicators of cellular senescence, and biological markers reflecting direct evidence need to be established. Genetic profiles are altered in senescent cells, letting these cells secrete pro-inflammatory molecules. Aging or age-related disorders including heart failure and atherosclerotic diseases link with an accumulation of cells undergoing cellular senescence in cardiovascular systems including heart and vessels. Senescent cells become pathogenic in most cases by mediating chronic sterile inflammation and tissue remodeling. A recent conceptual as well as technical breakthrough in this research area is "senolysis", meaning the specific elimination of senescent cells. Genetic as well as pharmacological models with senolysis contributed to reverse aging phenotypes and ameliorated pathologies in age-related disorders without enhancing the risk of tumorigenesis, and opened a new avenue for aging research. Several compounds are identified as senolytics, and some are already tested in clinical settings. It was recently reported that senolysis reverses aging phenotype in cardiovascular disorders. Generating therapies targeting suppression or elimination of senescent cells would inhibit the progression of undesirable aspects of aging, and become promising therapies for cardiac diseases.

Precision Analysis of the ^{136}Xe Two-Neutrino ββ Spectrum in KamLAND-Zen and Its Impact on the Quenching of Nuclear Matrix Elements

We present a precision analysis of the ^{136}Xe two-neutrino ββ electron spectrum above 0.8 MeV, based on high-statistics data obtained with the KamLAND-Zen experiment. An improved formalism for the two-neutrino ββ rate allows us to measure the ratio of the leading and subleading 2νββ nuclear matrix elements (NMEs), ξ_{31}^{2ν}=-0.26_{-0.25}^{+0.31}. Theoretical predictions from the nuclear shell model and the majority of the quasiparticle random-phase approximation (QRPA) calculations are consistent with the experimental limit. However, part of the ξ_{31}^{2ν} range allowed by the QRPA is excluded by the present measurement at the 90% confidence level. Our analysis reveals that predicted ξ_{31}^{2ν} values are sensitive to the quenching of NMEs and the competing contributions from low- and high-energy states in the intermediate nucleus. Because these aspects are also at play in neutrinoless ββ decay, ξ_{31}^{2ν} provides new insights toward reliable neutrinoless ββ NMEs.

Peptide vaccine for semaphorin3E ameliorates systemic glucose intolerance in mice with dietary obesity

We previously demonstrated that cellular aging signals upregulated a secreted class 3 semaphorin E (Sema3E) and its receptor plexinD1 in the adipose tissue of a murine model of dietary obesity and that Sema3E was a chemoattractant, mediating its biological effects by inducing infiltration of plexinD1-positive inflammatory macrophages into the visceral white adipose tissue. This study was performed to develop a peptide vaccine for Sema3E and test its therapeutic potential in a murine model of dietary obesity. Two antigenic peptides were selected to generate neutralizing antibodies for a vaccine. These peptides were conjugated to keyhole limpet hemocyanin (KLH), and were administered with Freund’s adjuvant to obese wild-type male mice. The Sema3E antibody titer was analyzed by ELISA, and the biological effects of the peptides were tested in mice with dietary obesity. Among the two candidate peptides, the Sema3E antibody titer was significantly increased by injection of KLH-conjugated HKEGPEYHWS (Sema3E vaccine). Administration of Sema3E vaccine suppressed the infiltration of plexinD1-positive cells, ameliorated chronic inflammation in visceral white adipose tissue, and improved systemic glucose intolerance in mice with dietary obesity, suggesting that Sema3E vaccine has the potential to become a next generation therapy for obesity and diabetes.

Role of smooth muscle cell p53 in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by remodeling and narrowing of the pulmonary arteries, which lead to elevation of right ventricular pressure, heart failure, and death. Proliferation of pulmonary artery smooth muscle cells (PASMCs) is thought to be central to the pathogenesis of PAH, although the underlying mechanisms are still being explored. The protein p53 is involved in cell cycle coordination, DNA repair, apoptosis, and cellular senescence, but its role in pulmonary hypertension (PH) is not fully known. We developed a mouse model of hypoxia-induced pulmonary hypertension (PH) and found significant reduction of p53 expression in the lungs. Our in vitro experiments with metabolomic analyses and the Seahorse XF extracellular flux analyzer indicated that suppression of p53 expression in PASMCs led to upregulation of glycolysis and downregulation of mitochondrial respiration, suggesting a proliferative phenotype resembling that of cancer cells. It was previously shown that systemic genetic depletion of p53 in a murine PH model led to more severe lung manifestations. Lack of information about the role of cell-specific p53 signaling promoted us to investigate it in our mouse PH model with the inducible Cre-loxP system. We generated a mouse model with SMC-specific gain or loss of p53 function by crossing Myh11-Cre/ERT2 mice with floxed Mdm4 mice or floxed Trp53 mice. After these animals were exposed to hypoxia for 4 weeks, we conducted hemodynamic and echocardiographic studies. Surprisingly, the severity of PH was similar in both groups of mice and there were no differences between the genotypes. Our findings in these mice indicate that activation or suppression of p53 signaling in SMCs has a minor role in the pathogenesis of PH and suggest that p53 signaling in other cells (endothelial cells, immune cells, or fibroblasts) may be involved in the progression of this condition.

p53 plays a crucial role in endothelial dysfunction associated with hyperglycemia and ischemia

p53 is a guardian of the genome that protects against carcinogenesis. There is accumulating evidence that p53 is activated with aging. Such activation has been reported to contribute to various age-associated pathologies, but its role in vascular dysfunction is largely unknown. The aim of this study was to investigate whether activation of endothelial p53 has a pathological effect in relation to endothelial function. We established endothelial p53 loss-of-function and gain-of-function models by breeding endothelial-cell specific Cre mice with floxed Trp53 or floxed Mdm2/Mdm4 mice, respectively. Then we induced diabetes by injection of streptozotocin. In the diabetic state, endothelial p53 expression was markedly up-regulated and endothelium-dependent vasodilatation was significantly impaired. Impairment of vasodilatation was significantly ameliorated in endothelial p53 knockout (EC-p53 KO) mice, and deletion of endothelial p53 also significantly enhanced the induction of angiogenesis by ischemia. Conversely, activation of endothelial p53 by deleting Mdm2/Mdm4 reduced both endothelium-dependent vasodilatation and ischemia-induced angiogenesis. Introduction of p53 into human endothelial cells up-regulated the expression of phosphatase and tensin homolog (PTEN), thereby reducing phospho-eNOS levels. Consistent with these results, the beneficial impact of endothelial p53 deletion on endothelial function was attenuated in EC-p53 KO mice with an eNOS-deficient background. These results show that endothelial p53 negatively regulates endothelium-dependent vasodilatation and ischemia-induced angiogenesis, suggesting that inhibition of endothelial p53 could be a novel therapeutic target in patients with metabolic disorders.

Boysenberry polyphenol inhibits endothelial dysfunction and improves vascular health

Endothelial cells have an important role in maintaining vascular homeostasis. Age-related disorders (including obesity, diabetes, and hypertension) or aging per se induce endothelial dysfunction that predisposes to the development of atherosclerosis. Polyphenols have been reported to suppress age-related endothelial cell disorders, but their role in vascular function is yet to be determined. We investigated the influence of boysenberry polyphenol on vascular health under metabolic stress in a murine model of dietary obesity. We found that administration of boysenberry polyphenol suppressed production of reactive oxygen species (ROS) and increased production of nitric oxide (NO) in the aorta. It has been reported that p53 induces cellular senescence and has a crucial role in age-related disorders, including heart failure and diabetes. Administration of boysenberry polyphenol significantly reduced the endothelial p53 level in the aorta and ameliorated endothelial cell dysfunction in iliac arteries under metabolic stress. Boysenberry polyphenol also reduced ROS and p53 levels in cultured human umbilical vein endothelial cells (HUVECs), while increasing NO production. Uncoupled endothelial nitric oxide synthase (eNOS monomer) is known to promote ROS production. We found that boysenberry polyphenol reduced eNOS monomer levels both in vivo and in vitro, along with an increase of eNOS dimerization. To investigate the components of boysenberry polyphenol mediating these favorable biological effects, we extracted the anthocyanin fractions. We found that anthocyanins contributed to suppression of ROS and p53, in association with increased NO production and eNOS dimerization. In an ex vivo study, anthocyanins promoted relaxation of iliac arteries from mice with dietary obesity. These findings indicate that boysenberry polyphenol and anthocyanins, a major component of this polyphenol, inhibit endothelial dysfunction and contribute to maintenance of vascular homeostasis.