Abstract 220: Emerging Roles of Altered NAD Metabolism in Diabetic Cardiomyopathy

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Chi Fung Lee
Keyword(s):  
Diastolic Dysfunction ◽  
Diabetic Cardiomyopathy ◽  
Cardiac Dysfunction ◽  
Troponin I ◽  
Redox Balance ◽  
Heart Weight ◽  
Mrna Levels ◽  
Nad Metabolism ◽  
Redox Imbalance ◽  
Nad Synthesis

Diabetes is linked to altered NAD metabolism whose causal roles in cardiac dysfunction are poorly understood. Synthesis, consumption and redox balance of NAD dictate NAD metabolism and its homeostasis, and we here explored their roles in diabetic cardiomyopathy. 16 week of Type 1 diabetes (T1D) to C57BL6N mice was associated with lowered cardiac NAD/NADH, mild systolic and more severe diastolic dysfunction. We next used mouse models with altered NAD metabolism to determine how NAD redox balance impacts diabetic cardiomyopathy. Using cardiac-specific Ndufs4-KO mice (cKO) as a model of latent decrease in cardiac NAD/NADH, we observed accelerated systolic and diastolic dysfunction (lowered fractional shortening, E’/A’ ratio, and increased e/E’ ratio) in male cKO mice stressed with chronic T1D. Cardiac hypertrophy (heart weight/tibia length), insulin depletion and hyperglycemia levels were similar in these mice. Serum metabolomic analyses (~240 metabolites) also showed unchanged aqueous and lipid metabolite levels, suggesting that the diabetic stresses on these hearts were similar. The accelerated dysfunction of T1D cKO hearts was also observed in another female cohort. Importantly, elevation of cardiac NAD levels to attenuate NAD redox imbalance mitigated the accelerated dysfunction of T1D cKO hearts. In another cohort, control and cKO mice were stressed by 16-week high fat diet feeding. Accelerated systolic and diastolic dysfunction, and increased hypertrophy were observed in T2D cKO mice with similar glycemic levels to control mice. The data suggested that NAD redox imbalance is a positive regulator of cardiac dysfunction induced by T1D or T2D. However, NAD-dependent pathogenic mechanism induced by T1D or T2D (e.g. hypertrophy) can be different, and is under further investigation. Tissue fibrosis and mRNA levels of pro-fibrotic genes, including Adamts proteinases, integrins, laminins, matrix metalloproteinases and collagens were unchanged in T1D cKO hearts. Therefore, the accelerated dysfunction of T1D cKO hearts is due to cardiomyocyte dysfunction. We examined how NAD metabolism, other than the redox balance, may alter cardiomyocyte function. Levels of metabolite and mRNA regulating NAD synthesis and consumption pathways were measured. Of 32 transcripts assayed, Nmrk2 levels were uniquely up-regulated in T1D cKO hearts, and lowered by elevation of cardiac NAD levels. NMRK product levels were concomitantly decreased in T1D cKO hearts. NAD-dependent global acetylation and inhibitory superoxide dismutase 2 acetylation were increased in T1D cKO hearts. Protein oxidation levels were concomitantly raised. Hyperacetylation in proteins like CaM kinase was associated with increased phosphorylation in troponin I, not in MyBPC or PLN in T1D cKO hearts. These data support the emerging, multifaceted roles of altered NAD metabolism in the progression of diabetic cardiomyopathy.

scholarly journals NAD+ Redox Imbalance in the Heart Exacerbates Diabetic Cardiomyopathy

2020 ◽  
Author(s):  
Ying Ann Chiao ◽  
Akash Deep Chakraborty ◽  
Christine M. Light ◽  
Rong Tian ◽  
Junichi Sadoshima ◽  
...  
Keyword(s):  
Diabetic Cardiomyopathy ◽  
Cardiac Dysfunction ◽  
Troponin I ◽  
Therapeutic Potential ◽  
Redox Balance ◽  
Diabetic Mice ◽  
Nicotinamide Phosphoribosyltransferase ◽  
Redox Imbalance ◽  
Nadh Ratio ◽  
Regulate Protein

AbstractBackgroundDiabetes is a risk factor of heart failure and promotes cardiac dysfunction. Diabetic tissues are associated with NAD+ redox imbalance; however, the hypothesis that NAD+ redox imbalance leads to dysfunction of diabetic hearts has not been tested. In this study, we employed mouse models with altered NAD+ redox balance to test the hypothesis.Methods and ResultsDiabetes was induced in C57BL/6 mice by streptozotocin injections, and diabetic cardiomyopathy (DCM) was allowed to develop for 16 weeks. Diabetic stress led to cardiac dysfunction and lowered NAD+/NADH ratio. This diabetogenic regimen was administered to cardiac-specific knockout mice of complex I subunit Ndufs4 (cKO), a model with lowered cardiac NAD+/NADH ratio without baseline dysfunction. Cardiac NAD+ redox imbalance in cKO hearts exacerbated systolic and diastolic dysfunction of diabetic mice in both sexes. Collagen levels and transcript analyses of fibrosis and extracellular matrix-dependent pathways did not show change in diabetic cKO hearts, suggesting that the exacerbated cardiac dysfunction was likely due to cardiomyocyte dysfunction. We found that cardiac NAD+ redox imbalance promoted superoxide dismutase 2 (SOD2) acetylation, protein oxidation, induced troponin I S150 phosphorylation and impaired energetics in diabetic cKO hearts. Importantly, elevation of cardiac NAD+ levels by nicotinamide phosphoribosyltransferase (NAMPT) normalized NAD+ redox balance, over-expression alleviated cardiac dysfunction and reversed pathogenic mechanisms in diabetic mice.ConclusionOur results show that NAD+ redox imbalance to regulate protein acetylation and phosphorylation is a critical mediator of the progression of DCM, and suggest the therapeutic potential of harnessing NAD+ metabolism in DCM.

scholarly journals NAD + Redox Imbalance in the Heart Exacerbates Diabetic Cardiomyopathy

2021 ◽  
Author(s):  
Ying Ann Chiao ◽  
Akash Deep Chakraborty ◽  
Christine M. Light ◽  
Rong Tian ◽  
Junichi Sadoshima ◽  
...  
Keyword(s):  
Mouse Models ◽  
Diabetic Cardiomyopathy ◽  
Cardiac Dysfunction ◽  
Nicotinamide Adenine Dinucleotide ◽  
Redox Balance ◽  
Diabetic Mice ◽  
Redox Imbalance ◽  
Diastolic Velocity ◽  
Nadh Ratio ◽  
Fractional Shortening

Background: Diabetes is a risk factor for heart failure and promotes cardiac dysfunction. Diabetic tissues are associated with nicotinamide adenine dinucleotide (NAD + ) redox imbalance; however, the hypothesis that NAD + redox imbalance causes diabetic cardiomyopathy has not been tested. This investigation used mouse models with altered NAD + redox balance to test this hypothesis. Methods: Diabetic stress was induced in mice by streptozotocin. Cardiac function was measured by echocardiography. Heart and plasma samples were collected for biochemical, histological, and molecular analyses. Two mouse models with altered NAD + redox states (1, Ndufs4 [NADH:ubiquinone oxidoreductase subunit S4] knockout, cKO, and 2, NAMPT [nicotinamide phosphoribosyltranferase] transgenic mice, NMAPT) were used. Results: Diabetic stress caused cardiac dysfunction and lowered NAD + /NADH ratio (oxidized/reduced ratio of nicotinamide adenine dinucleotide) in wild-type mice. Mice with lowered cardiac NAD + /NADH ratio without baseline dysfunction, cKO mice, were challenged with chronic diabetic stress. NAD + redox imbalance in cKO hearts exacerbated systolic (fractional shortening: 27.6% versus 36.9% at 4 weeks, male cohort P <0.05), and diastolic dysfunction (early-to-late ratio of peak diastolic velocity: 0.99 versus 1.20, P <0.05) of diabetic mice in both sexes. Collagen levels and transcripts of fibrosis and extracellular matrix–dependent pathways did not show changes in diabetic cKO hearts, suggesting that the exacerbated cardiac dysfunction was due to cardiomyocyte dysfunction. NAD + redox imbalance promoted superoxide dismutase 2 acetylation, protein oxidation, troponin I S150 phosphorylation, and impaired energetics in diabetic cKO hearts. Importantly, elevation of cardiac NAD + levels by NAMPT normalized NAD + redox balance, alleviated cardiac dysfunction (fractional shortening: 40.2% versus 24.8% in cKO:NAMPT versus cKO, P <0.05; early-to-late ratio of peak diastolic velocity: 1.32 versus 1.04, P <0.05), and reversed pathogenic mechanisms in diabetic mice. Conclusions: Our results show that NAD + redox imbalance to regulate acetylation and phosphorylation is a critical mediator of the progression of diabetic cardiomyopathy and suggest the therapeutic potential for diabetic cardiomyopathy by harnessing NAD + metabolism.

Abstract MP211: NAD Redox Imbalance Exacerbates Diabetic Cardiomyopathy

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Chi Fung Lee
Keyword(s):  
Diastolic Dysfunction ◽  
Diabetic Cardiomyopathy ◽  
Calcium Sensitivity ◽  
Redox Balance ◽  
Diabetic Control ◽  
Redox Imbalance ◽  
Nadh Ratio ◽  
Streptozotocin Induced Diabetes ◽  
Systolic And Diastolic Function ◽  
Myofilament Calcium Sensitivity

Diabetes and heart failure are linked to NAD redox imbalance, whose role in diabetic cardiomyopathy has not been directly tested. Streptozotocin-induced diabetes in WT mice for 16 weeks promoted declines in systolic and diastolic function, which associated with lowered cardiac NAD/NADH ratio (NAD redox imbalance). To test the hypothesis that , we employed mouse models with cardiac-specific manipulations of NAD redox states. Cardiac-specific Ndufs4-KO mice (cKO) exhibit lowered cardiac NAD/NADH ratio with normal baseline function, geometry and energetics. Control and cKO mice were challenged with 8-week diabetic stress. Metabolomic analyses of plasma collected after the diabetic stress showed similar hyperglycemia and dyslipidemia stresses in diabetic control and diabetic cKO mice. Chronic diabetic stress promoted systolic and diastolic dysfunctions in control mice, which were further exacerbated in diabetic cKO mice in both male and female cohorts. Collagen levels and transcript analyses of fibrosis and extracellular matrix-dependent pathways showed no change in diabetic cKO hearts, suggesting that cardiomyocyte dysfunction is a likely culprit for the exacerbated dysfunction. Increased protein acetylation, including SOD2-K68Ac, was observed in diabetic cKO hearts. Inhibited antioxidant function by SOD2-K68Ac promoted protein oxidation in diabetic cKO hearts, suggesting oxidative stress as a pathogenic mechanism. We next examined phosphorylation status of myofilament proteins in these diabetic hearts. MyBPC-S282Pi levels are suppressed in failing hearts and remained unchanged in diabetic cKO hearts. TnI-S150Pi increases myofilament calcium sensitivity and prolongs calcium dissociation, while TnI-S23/24Pi imposes the opposite effects. TnI-S150Pi levels were elevated in diabetic cKO hearts, while TnI-S23/24Pi levels unchanged. Therefore, exacerbated diastolic dysfunction in diabetic cKO hearts is due to the selective phosphorylation at TnI-S150. AMPK is activated by energetic stress and phosphorylates TnI-S150. ATP levels decreased, and AMP/ATP ratio increased in diabetic cKO hearts, implicating impaired energetics to promote TnI-S150Pi and dysfunction. Elevation of NAD levels normalized cardiac NAD redox balance in diabetic cKO hearts. Elevated levels of SOD2-K68Ac and TnI-S150Pi, exacerbated systolic and diastolic dysfunction in diabetic cKO hearts were all reversed by elevation of NAD levels. Dysfunction in diabetic control hearts was also ameliorated by elevation of NAD levels. These data collectively conclude that NAD redox imbalance is a positive mediator of the progression of diabetic cardiomyopathy.

scholarly journals Pathway analysis of NAD+ metabolism

2011 ◽  
Vol 439 (2) ◽  
pp. 341-348 ◽  
Author(s):  
Luis F. de Figueiredo ◽  
Toni I. Gossmann ◽  
Mathias Ziegler ◽  
Stefan Schuster
Keyword(s):  
Dna Repair ◽  
De Novo ◽  
Redox Balance ◽  
Transfer Reactions ◽  
Biosynthetic Pathways ◽  
De Novo Synthesis ◽  
Systematic Analysis ◽  
Nad Metabolism ◽  
Nad Synthesis ◽  
Futile Cycles

NAD+ is well known as a crucial cofactor in the redox balance of metabolism. Moreover, NAD+ is degraded in ADP-ribosyl transfer reactions, which are important components of multitudinous signalling reactions. These include reactions linked to DNA repair and aging. In the present study, using the concept of EFMs (elementary flux modes), we established all of the potential routes in a network describing NAD+ biosynthesis and degradation. All known biosynthetic pathways, which include de novo synthesis starting from tryptophan as well as the classical Preiss–Handler pathway and NAD+ synthesis from other vitamin precursors, were detected as EFMs. Moreover, several EFMs were found that degrade NAD+, represent futile cycles or have other functionalities. The systematic analysis and comparison of the networks specific for yeast and humans document significant differences between species with regard to the use of precursors, biosynthetic routes and NAD+-dependent signalling.

Abstract 16563: FOXO1 Induces Cardiomyocyte-KLF5, Which Drives Oxidative Stress and Diabetic Cardiomyopathy

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Ioannis D Kyriazis ◽  
Matthew K Hoffman ◽  
Lea Gaignebet ◽  
Anna Maria Lucchese ◽  
Chao Wang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Diabetic Cardiomyopathy ◽  
Cardiac Dysfunction ◽  
Constitutive Expression ◽  
Diabetic Patients ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Lipid Species ◽  
Ceramide Accumulation ◽  
Klf5 Expression

Introduction: Cardiomyopathy in type 1 diabetes (T1D) is accompanied by impaired mitochondrial function, oxidative stress and lipotoxicity. We showed that cardiomyocyte (CM) Krüppel-like factor 5 (KLF5) is increased in streptozotocin-induced T1D and induces Peroxisome Proliferator Activated Receptor (PPAR)α in mice. Hypothesis: KLF5 upregulation by FOXO1 induces diabetic cardiomyopathy (DbCM). Methods and Results: Analyses in CM from diabetic patients showed higher KLF5 mRNA levels compared to non-diabetic individuals. In vitro mechanistic and in vivo analyses in αMHC- Foxo1 -/- mice revealed that FOXO1 stimulates KLF5 expression via direct promoter binding. Genetic inhibition of CM FOXO1 alleviated DbCM. Additionally, AAV-mediated CM-specific KLF5 overexpression in C57Bl/6 (WT) mice induced cardiac dysfunction. Mice with CM-specific KLF5 constitutive expression (αMHC-rtTA- Klf5 ), which we generated, recapitulated cardiomyopathy without T1D. Moreover, Pparα -/- mice with T1D, had higher CM-KLF5 levels and developed DbCM, suggesting that KLF5-driven DbCM is PPARα-independent. Additionally, CM-KLF5 induced oxidative stress through increased NADPH oxidase (NOX)4 expression and lower mitochondria abundance. Conversely, KLF5 inhibition prevented NOX4 upregulation and superoxide formation. Furthermore, CM-KLF5 promoted NOX4 expression via direct promoter binding. Antioxidant treatment in diabetic WT and αMHC-rtTA- Klf5 mice alleviated cardiac dysfunction partially, suggesting other pathways that contribute in KLF5-induced DbCM. For that, we performed cardiac lipidome analysis where we found clustering of αMHC-rtTA- Klf5 with diabetic WT mice. Of note, KLF5 inhibition in diabetic mice resulted in similar lipidome with non-diabetic WT mice. Individual lipid species analysis showed increased ceramide accumulation in diabetic WT and αMHC-rtTA- Klf5 mice that was reversed upon KLF5 inhibition. Thus, CM-KLF5 activation correlates with cardiac ceramide accumulation, that has been associated with cardiac lipotoxicity. Conclusions: In conclusion, T1D stimulates FOXO1, which induces CM-KLF5 expression that leads to oxidative stress and DbCM in a non-PPARα-dependent manner, as well as to cardiac ceramide accumulation.

Abstract P173: Caloric Restriction Attenuates Diabetic Cardiomyopathy Through the Recruitment of the Antioxidant System

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Maayan Waldman ◽  
Keren Cohen ◽  
Michael Arad ◽  
Nader G Abraham ◽  
Michal Laniado-Schwartzman ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Caloric Restriction ◽  
Diabetic Cardiomyopathy ◽  
Diabetic Heart ◽  
Heart Weight ◽  
Internal Diameter ◽  
Mrna Levels ◽  
Diabetic Mice ◽  
Antioxidant Genes ◽  
Obesity And Diabetes

Introduction: Insulin resistance negatively impacts the diabetic heart in various ways, that include impaired insulin-mediated glucose uptake and a reduction in intracellular signalling. Diabetic cardiomyopathy is independent of coronary artery disease and is characterized by increased oxidative stress and extensive fibrotic changes, leading to increased myocardial stiffness and the development of diastolic dysfunction. Caloric restriction (CR) is cardioprotective mainly through its catabolic activity and increased insulin sensitivity. We examined the effect of CR on the development of diabetic cardiomyopathy and changes in oxidative stress and antioxidant genes. Methods: Leptin resistant (db/db) mice suffer from obesity and diabetes. Mice were treated for 4 weeks with angiotensin II (AT) to induce severe cardiomyopathy. Mice under CR were fed 90% of their normal food intake for 2 weeks and 65% for an additional 2 weeks. Each group consisted of 5-6 animals. Results: CR attenuated obesity and the cardiomyopathy phenotype in diabetic mice. CR reduced body weight and heart weight in diabetic mice when compared to control animals (33.7±7.9g vs.44 ±5.9g; 0.137±0.023g vs. 0.17±0.02g respectively, p<0.05); and lowered blood glucose (576±167mg/dL vs 702.5±309 mg/dL, p<0.05). Echocardiography indicated that CR attenuated the hypertrophic phenotype in the diabetic mice when compared to control animals (LV internal diameter 3.34±0.46mm vs. 4.06±0.36mm, p<0.01). Diabetic mice treated with AT suffer from oxidative stress as evident in a 110% increase in serum MDA levels (p<0.011), a reduction of 81% in adiponectin (p<0.001) and 65% in PGC-1α (p<0.0046) mRNA levels in cardiac tissue of diabetic mice compared to WT mice. The attenuation of diabetic cardiomyopathy after CR was accompanied by a reduction in serum MDA levels (p<0.028) and an increase in cardiac adiponectin, HO-1 and PGC-1α levels (p<0.05). Conclusion: These results indicate that a short term CR attenuated the development of AT induced diabetic cardiomyopathy through the activation of the adiponectin- PGC-1α- HO-1-axis. This appears to be a critical module in protecting the diabetic heart from the development of cardiomyopathy.

Abstract 204: Loss Of Akt Caused Aging-induced Cardiac Systolic Dysfunction But Is Independent From Comorbid Diastolic Dysfunction In Aging.

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Morihiko Aoyama ◽  
Yasuko K Bando ◽  
Akio Monji ◽  
Toko Mitusi ◽  
Haruya Kawase ◽  
...  
Keyword(s):  
Diastolic Dysfunction ◽  
Cardiac Dysfunction ◽  
Systolic Dysfunction ◽  
The Body ◽  
Heart Weight ◽  
Control Groups ◽  
Cardiac Geometry ◽  
Induced Changes ◽  
Sam Mice

PURPOSE: Aging is one of the primary factors causing cardiac dysfunction. Diastolic dysfunction (DD) is primary characteristics for aging-induced heart failure. Clinical evidences demonstrate a sustained exercise (EX) ameliorates DD; however, it remains unclear whether EX may ameliorate the aging-related DD and the underlying molecular mechanism. We thus evaluated whether EX may ameliorate cardiac dysfunction in aging and the role of Akt in the EX-induced effects on aging heart. Methods: Male senescence-accelerated (SAM) mice (P10) and its aging-resistant control (R1) were allocated to exercise [EX; 60-min running on treadmill every single day for 6 months (P10-EX and R1-EX)] and exercise-free control groups (P10-ctl and R1-ctl). Age-matched C57BL6 mice were subjected to the same EX protocol (C57-EX and C57-ctl) to compare any influence of genetic background. To elucidate the role of Akt in aging-induced changes in heart, analysis of aged Akt knockout mice (AktKO) were conducted. Results: At baseline, cardiac geometry of R1 strain revealed normal, whereas P10 strain exhibited reduced LV wall thickness and DD. The s-LVF of both strains was preserved. After EX, the body and heart weight of R1 mice were increased (BW; +6.7% and HW; +3.5% versus R1-ctl); however, EX had no influence on BW and HW of P10. EX promoted LV hypertrophy in R1, which was absent in P10-EX. The d-LVF of R1-EX was impaired but their s-LVF was unchanged. In contrast, s-LVF of P10-EX turned impaired [EF(%) 68.9±1.5 vs 74.3±1.2 for P10-ctl], whereas the underlying DD of P10 was unaffected by EX. In C57-EX, cardiac function exhibited the similar trends observed in R1-EX. Cardiac Akt activity of R1-EX and C57-EX were enhanced compared to controls, which was diminished in P10-EX. Aged AktKO exhibited impaired s-LVF [EF(%)61.3±1.0], nonetheless their DD remained unchanged [E/A=2.5±0.3, Dct (msec)= 35.0±2.4]. Conclusions: Our study demonstrates that #1 Akt is essential for adaptive response of LV hypertrophy to EX, #2 aging impairs Akt signaling in heart, leading to systolic dysfunction, and #3 Akt is independent from modulation of cardiac DD induced by aging. Clinical implications are drawn that the benefit of EX on DD may be irrelevant to the aged population.

scholarly journals NADH/NAD+ Redox Imbalance and Diabetic Kidney Disease

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 730
Author(s):  
Liang-Jun Yan
Keyword(s):  
Kidney Disease ◽  
Diabetic Kidney Disease ◽  
Redox Balance ◽  
Pathophysiological Mechanism ◽  
Diabetic Kidney ◽  
Nad Metabolism ◽  
Redox Imbalance ◽  
Nadh Generation ◽  
Stage Renal Disease ◽  
End Stage

Diabetic kidney disease (DKD) is a common and severe complication of diabetes mellitus. If left untreated, DKD can advance to end stage renal disease that requires either dialysis or kidney replacement. While numerous mechanisms underlie the pathogenesis of DKD, oxidative stress driven by NADH/NAD+ redox imbalance and mitochondrial dysfunction have been thought to be the major pathophysiological mechanism of DKD. In this review, the pathways that increase NADH generation and those that decrease NAD+ levels are overviewed. This is followed by discussion of the consequences of NADH/NAD+ redox imbalance including disruption of mitochondrial homeostasis and function. Approaches that can be applied to counteract DKD are then discussed, which include mitochondria-targeted antioxidants and mimetics of superoxide dismutase, caloric restriction, plant/herbal extracts or their isolated compounds. Finally, the review ends by pointing out that future studies are needed to dissect the role of each pathway involved in NADH-NAD+ metabolism so that novel strategies to restore NADH/NAD+ redox balance in the diabetic kidney could be designed to combat DKD.

Treatment with methotrexate carried in lipid core nanoparticles prevents the development of diastolic dysfunction in septic rats

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
N.M Lopes ◽  
M.C Guido ◽  
C.I Albuquerque ◽  
L Jensen ◽  
V.M Miura ◽  
...  
Keyword(s):  
Protein Expression ◽  
Diastolic Dysfunction ◽  
Cardiac Dysfunction ◽  
Density Lipoprotein ◽  
B Cell Lymphoma ◽  
Posterior Wall ◽  
The Other ◽  
Heart Weight ◽  
Control Group ◽  
Funding Source

Abstract Introduction In the development of sepsis, besides the dysregulation of the immune system and disturbances of several vital organs, life-threatening cardiac dysfunction often occurs. Previously, we showed that non-protein nanoparticles that resemble the lipid structure of low-density lipoprotein, termed LDE, concentrate in inflammatory sites. When incorporated in LDE, the cellular uptake of MTX increases several-fold compared to the uptake of commercial MTX. The novel LDE-MTX formulation was shown to have the ability to modulate the immune response in in rabbits with atherosclerosis and in rats with myocardial infarction. LDE-MTX reduced the inflammation and improved the post-infarction cardiac function by increasing the release of angiogenesis, thereby improving hypoxia. The aim of the current study was to test the hypothesis whether LDE-MTX could also improve the cardiac status in septic rats. Methods Septicemia was induced in Wistar rats by two I.P. injections of lipopolysaccharide (LPS, 10mg/kg) administered with a 24h interval. Rats were allocated to control group (CT, without sepsis; n=5) and 3 groups with sepsis: LDE (n=7), treated with LDE only; MTX (n=6), with commercial MTX (1mg/kg); and LDE-MTX (n=7), with LDE-MTX (1mg/kg). Echocardiography was performed 72h after sepsis induction. Animals were euthanised and LV tissues were collected for protein expression analysis of inflammatory, apoptotic, angiogenesis, hypoxia and adenosine bioavailability markers. Results Septic rats treated with LDE developed diastolic dysfunction and presented decreased diastolic volume and diameter of the LV. Treatment with LDE-MTX totally prevented the appearance of diastolic dysfunction and the alterations in LV diastolic dilation. Also, LDE-MTX treatment elicited cardiac hypertrophy through the increase of the thickness of septum and of the LV posterior wall. LDE-MTX increased LV mass and the relative heart weight, as compared to the other 3 groups. There were no differences in the protein expression of inflammatory (lymphocytes, tumor necrosis factor, interleukins) and apoptotic (caspases and B-cell lymphoma family) markers among the four groups. However, LDE-MTX showed higher expression of CD68 (macrophage marker). Angiogenesis was higher, while cellular hypoxia was lower in LDE-MTX, respectively represented by vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1 alpha, in comparison to the other 3 groups. The intracellular adenosine bioavailability was increased in LDE-MTX-treated animals, as promoted by the higher expression of the A1 receptor, as compared to CT. Conclusion The treatment with LDE-MTX was successful in precluding the appearance of the cardiac dysfunction associated to sepsis. This outcome was conceivably attained by different effects of the treatment observed here, such as those on angiogenesis, macrophage recruitment and adenosine bioavailability in the LV. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)

Abstract 219: NAD Redox Imbalance Accelerates Diabetic Cardiomyopathy via Protein Acetylation and Oxidative Stress

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Ying Ann Chiao ◽  
Christine Light ◽  
Xiaojian Shi ◽  
Rong Tian ◽  
Junichi Sadoshima ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mouse Models ◽  
Diabetic Cardiomyopathy ◽  
Cardiac Fibrosis ◽  
Redox Balance ◽  
Protein Acetylation ◽  
Redox Imbalance ◽  
Nadh Ratio ◽  
Systolic And Diastolic Function ◽  
And Oxidative Stress

Diabetes is long linked to lowered NAD/NADH ratio, aka NAD redox imbalance, but its causal role to diabetic cardiomyopathy is not established. We used mouse models with latent decrease in cardiac NAD/NADH ratio (cardiac-specific Ndufs4-KO, cKO) and elevated cardiac NAD levels to directly test whether cardiac NAD redox imbalance accelerates diabetic cardiomyopathy. Control and cKO mice were subjected to 8-week T1D stress, and longitudinal cardiac function was measured by echocardiography. Accelerated declines in systolic and diastolic function were observed in T1D cKO mice. Insulin depletion and hyperglycemia were similar in T1D control and T1D cKO mice, and serum metabolomic analyses showed unchanged aqueous and lipid metabolite levels. These metabolite results suggested that T1D control and cKO hearts were stressed under similar diabetic conditions. Importantly, elevation of cardiac NAD levels to attenuate NAD redox imbalance mitigated the accelerated functional declines in T1D cKO hearts. The data from mouse models with manipulated NAD redox states suggested that NAD redox imbalance accelerates diabetic cardiomyopathy. Cardiac fibrosis levels were not different in T1D control and cKO hearts, while transcript levels of fibrotic genes, including Adamts proteinases, integrins, laminins, matrix metalloproteinases and collagens, also showed no difference. Therefore, the accelerated functional declines in T1D cKO hearts are not due to altered extracellular matrix environment, but are rather due to cardiomyocyte dysfunction. We next determined whether the accelerated cardiac dysfunction is mediated via protein acetylation and oxidative stress. NAD-dependent global protein acetylation and inhibitory acetylation of superoxide dismutase 2 were elevated in T1D cKO hearts. Inhibition of SOD2 concomitantly promoted elevation of protein oxidation levels in T1D cKO hearts. The results suggested that NAD redox balance-dependent protein acetylation regulates oxidative stress to promote diabetic cardiomyopathy.

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