Cardioprotective effect of a moderate and prolonged exercise training involves sirtuin pathway

Aerobic training attenuates cardiac remodeling in mice post-myocardial infarction by inhibiting the p300/CBP-associated factor

Aerobic training (AT), an effective form of cardiac rehabilitation, has been shown to be beneficial for cardiac repair and remodeling after myocardial infarction (MI). The p300/CBP-associated factor (PCAF) is one of the most important lysine acetyltransferases and is involved in various biological processes. However, the role of PCAF in AT and AT-mediated cardiac remodeling post-MI has not been determined. Here, we found that the PCAF protein level was significantly increased after MI, while AT blocked the increase in PCAF. AT markedly improved cardiac remodeling in mice after MI by reducing endoplasmic reticulum stress (ERS). In vivo, similar to AT, pharmacological inhibition of PCAF by Embelin improved cardiac recovery and attenuated ERS in MI mice. Furthermore, we observed that both IGF-1, a simulated exercise environment, and Embelin protected from H2O2-induced cardiomyocyte injury, while PCAF overexpression by viruses or the sirtuin inhibitor nicotinamide eliminated the protective effect of IGF-1 in H9C2 cells. Thus, our data indicate that maintaining low PCAF levels plays an essential role in AT-mediated cardiac protection, and PCAF inhibition represents a promising therapeutic target for attenuating cardiac remodeling after MI.

Research progress on Sirtuins (SIRTs) family modulators

Sirtuins (SIRTs) represent a class of nicotinamide adenine dinucleotide (NAD+)-dependent protein deacetylases that exert a crucial role in cellular signal transduction and various biological processes. The mammalian sirtuins family encompasses SIRT1 to SIRT7, exhibiting therapeutic potential in counteracting cellular aging, modulating metabolism, responding to oxidative stress, inhibiting tumors, and improving cellular microenvironment. These enzymes are intricately linked to the occurrence and treatment of diverse pathological conditions, including cancer, autoimmune diseases, and cardiovascular disorders. Given the significance of histone modification in gene expression and chromatin structure, maintaining the equilibrium of the sirtuins family is imperative for disease prevention and health restoration. Mounting evidence suggests that modulators of SIRTs play a crucial role in treating various diseases and maintaining physiological balance. This review delves into the molecular structure and regulatory functions of the sirtuins family, reviews the classification and historical evolution of SIRTs modulators, offers a systematic overview of existing SIRTs modulation strategies, and elucidates the regulatory mechanisms of SIRTs modulators (agonists and inhibitors) and their clinical applications. The article concludes by summarizing the challenges encountered in SIRTs modulator research and offering insights into future research directions.

SIRT3 regulates mitochondrial function: A promising star target for cardiovascular disease therapy

Dysregulation of mitochondrial homeostasis is common to all types of cardiovascular diseases. SIRT3 regulates apoptosis and autophagy, material and energy metabolism, mitochondrial oxidative stress, inflammation, and fibrosis. As an important mediator and node in the network of mechanisms, SIRT3 is essential to many activities. This review explains how SIRT3 regulates mitochondrial homeostasis and the tricarboxylic acid cycle to treat common cardiovascular diseases. A novel description of the impact of lifestyle factors on SIRT3 expression from the angles of nutrition, exercise, and temperature is provided.

The long-term exercise after traumatic brain injury: Reharmonizing brain by sound body

Traumatic brain injuries (TBI) refer to multiple acquired dysfunctions arising from damage to the brain caused by an external force, including rapid acceleration/deceleration and concussion. Among them, mild TBI (mTBI) accounts for most cases (up to 90%) of injuries. It is responsible for a variety of symptoms, including anxiety, depression, and cognitive impairments that remain difficult to be treated. It has been reported that regular physical activity, as well as, improving life quality, display a neuroprotective function, suggesting a possible role in post-traumatic rehabilitation. In this study, we investigated the effects of treadmill exercise in a mice mTBI model by behavioural, electrophysiological and neurochemical analysis. Daily exercise decreased anxiety, aggressive behavior, and depression in mTBI mice. Accordingly, electrophysiological and neurochemical maladaptive rearrangement occurring in the hippocampus of mTBI mice were prevented by the exercise.

A systematic review and meta-analysis of the SIRT1 response to exercise

Sirtuin 1 (SIRT1) is a key physiological regulator of metabolism and a target of therapeutic interventions for cardiometabolic and ageing-related disorders. Determining the factors and possible mechanisms of acute and adaptive SIRT1 response to exercise is essential for optimising exercise interventions aligned to the prevention and onset of disease. Exercise-induced SIRT1 upregulation has been reported in animals, but, to date, data in humans have been inconsistent. This exploratory systematic review and meta-analysis aims to assess various exercise interventions measuring SIRT1 in healthy participants. A total of 34 studies were included in the meta-analysis (13 single bout exercise, 21 training interventions). Studies were grouped according to tissue sample type (blood, muscle), biomarkers (gene expression, protein content, enzyme level, enzyme activity), and exercise protocols. A single bout of high-intensity or fasted exercise per se increases skeletal muscle SIRT1 gene expression as measured by qPCR or RT-PCR, while repeated resistance training alone increases blood SIRT1 levels measured by ELISA. A limited number of studies also show a propensity for an increase in muscle SIRT1 activity as measured by fluorometric or sirtuin activity assay. In conclusion, exercise acutely upregulates muscle SIRT1 gene expression and chronically increases SIRT1 blood enzyme levels.

Role of SIRT3 in neurological diseases and rehabilitation training

Sirtuin3 (SIRT3) is a deacetylase that plays an important role in normal physiological activities by regulating a variety of substrates. Considerable evidence has shown that the content and activity of SIRT3 are altered in neurological diseases. Furthermore, SIRT3 affects the occurrence and development of neurological diseases. In most cases, SIRT3 can inhibit clinical manifestations of neurological diseases by promoting autophagy, energy production, and stabilization of mitochondrial dynamics, and by inhibiting neuroinflammation, apoptosis, and oxidative stress (OS). However, SIRT3 may sometimes have the opposite effect. SIRT3 can promote the transfer of microglia. Microglia in some cases promote ischemic brain injury, and in some cases inhibit ischemic brain injury. Moreover, SIRT3 can promote the accumulation of ceramide, which can worsen the damage caused by cerebral ischemia-reperfusion (I/R). This review comprehensively summarizes the different roles and related mechanisms of SIRT3 in neurological diseases. Moreover, to provide more ideas for the prognosis of neurological diseases, we summarize several SIRT3-mediated rehabilitation training methods.

Ursolic acid enhances the effect of exercise training on vascular aging by reducing oxidative stress in aged type 2 diabetic rats

Ursolic acid (UA) mediates the vasorelaxant activity via nitric oxide (NO) release, and upregulation of endothelial nitric oxide synthase (eNOS) in endothelial cells (ECs) in disease conditions with increased oxidative stress (OS). The present study aimed to reflect on the impact of 8 weeks of a combination of UA supplementation and resistance/endurance training in old male Wistar rats having a high-fat diet and/or low-dose streptozotocin-induced type 2 diabetes (HFD/STZ-induced T2D), with an emphasis on Sirtuin 1 (SIRT1)-endothelial nitric oxide synthase (eNOS) axis and OS indices in their aortic tissues. A total number of56 21-month-old male Wistar rats with HFD/STZ-induced T2D were randomized into seven groups (n = eight animals per group): (1) sedentary old nondiabetic (Control [C]); (2) sedentary HFD/STZ-induced T2D (Diabetic [D]); (3) sedentary HFD/STZ-induced T2D plus UA (Diabetic + Ursolic Acid [DU]); (4) endurance-trained HFD/STZ-induced T2D (Diabetic + Endurance Training [DE]); (5) resistance-trained HFD/STZ-induced T2D (Diabetic + Resistance Training [DR]); (6) endurance-trained HFD/STZ-induced T2D plus UA (Diabetic + Endurance Training + Ursolic Acid [DEU]); and (7) resistance-trained STZ-diabetic plus UA (Diabetic + Resistance Training + Ursolic Acid [DRU]) rats. The ladder-based resistance training group performed the ladder resistance training at 60% of the maximum voluntary carrying capacity (MVCC), 14-20 climbs in each session, with a one-min rest between each two trials, 5 days a week. The treadmill-based endurance exercise training protocol consisted of repeated bouts of high- and low-intensity training with 60-75% maximal running speed and 30%-40% maximal running speed in the course of 8 weeks, respectively. The animals in the supplement groups also took 500 mg of UA/kg of high-fat diet/day, resulting in a daily UA intake of approximately 250 mg UA per kg of body weight rat/day. The resistance/endurance training plus the UA consumption could partially reverse the levels of malondialdehyde (MDA), nitric oxide (NO), as well as total antioxidant capacity (TAC). It was concluded that oral 0.5% UA supplementation can prevent vascular aging biomarkers in a HFD/STZ-induced T2D model. Further studies are also required to clarify how chronic consumption of UA with/without training protocols reverses vascular aging process.

Effect of exercise training on cardiac mitochondrial respiration, biogenesis, dynamics, and mitophagy in ischemic heart disease

Objective

Cardiac mitochondrial dysfunction was found in ischemic heart disease (IHD). Hence, this study determined the effects of exercise training (ET) on cardiac mitochondrial respiration and cardiac mitochondrial quality control in IHD.

Methods

A narrative synthesis was conducted after searching animal studies written in English in three databases (PubMed, Web of Science, and EMBASE) until December 2020. Studies that used aerobic exercise as an intervention for at least 3 weeks and had at least normal, negative (sedentary IHD), and positive (exercise-trained IHD) groups were included. The CAMARADES checklist was used to check the quality of the included studies.

Results

The 10 included studies (CAMARADES score: 6–7/10) used swimming or treadmill exercise for 3–8 weeks. Seven studies showed that ET ameliorated cardiac mitochondrial respiratory function as manifested by decreased reactive oxygen species (ROS) production and increased complexes I-V activity, superoxide dismutase 2 (SOD2), respiratory control ratio (RCR), NADH dehydrogenase subunits 1 and 6 (ND1/6), Cytochrome B (CytB), and adenosine triphosphate (ATP) production. Ten studies showed that ET improved cardiac mitochondrial quality control in IHD as manifested by enhanced and/or controlled mitochondrial biogenesis, dynamics, and mitophagy. Four other studies showed that ET resulted in better cardiac mitochondrial physiological characteristics.

Conclusion

Exercise training could improve cardiac mitochondrial functions, including respiration, biogenesis, dynamics, and mitophagy in IHD.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=226817, identifier: CRD42021226817.

Exercise-induced signaling pathways to counteracting cardiac apoptotic processes

Cardiovascular diseases are the most common cause of death in the world. One of the major causes of cardiac death is excessive apoptosis. However, multiple pathways through moderate exercise can reduce myocardial apoptosis. After moderate exercise, the expression of anti-apoptotic proteins such as IGF-1, IGF-1R, p-PI3K, p-Akt, ERK-1/2, SIRT3, PGC-1α, and Bcl-2 increases in the heart. While apoptotic proteins such as PTEN, PHLPP-1, GSK-3, JNK, P38MAPK, and FOXO are reduced in the heart. Exercise-induced mechanical stress activates the β and α5 integrins and subsequently, focal adhesion kinase phosphorylation activates the Akt/mTORC1 and ERK-1/2 pathways, leading to an anti-apoptotic response. One of the reasons for the decrease in exercise-induced apoptosis is the decrease in Fas-ligand protein, Fas-death receptor, TNF-α receptor, Fas-associated death domain (FADD), caspase-8, and caspase-3. In addition, after exercise mitochondrial-dependent apoptotic factors such as Bid, t-Bid, Bad, p-Bad, Bak, cytochrome c, and caspase-9 are reduced. These changes lead to a reduction in oxidative damage, a reduction in infarct size, a reduction in cardiac apoptosis, and an increase in myocardial function. After exercising in the heart, the levels of RhoA, ROCK1, Rac1, and ROCK2 decrease, while the levels of PKCε, PKCδ, and PKCɑ are activated to regulate calcium and prevent mPTP perforation. Exercise has an anti-apoptotic effect on heart failure by increasing the PKA-Akt-eNOS and FSTL1-USP10-Notch1 pathways, reducing the negative effects of CaMKIIδ, and increasing the calcineurin/NFAT pathway. Exercise plays a protective role in the heart by increasing HSP20, HSP27, HSP40, HSP70, HSP72, and HSP90 along with increasing JAK2 and STAT3 phosphorylation. However, research on exercise and factors such as Pim-1, Notch, and FAK in cardiac apoptosis is scarce, so further research is needed. Future research is recommended to discover more anti-apoptotic pathways. It is also recommended to study the synergistic effect of exercise with gene therapy, dietary supplements, and cell therapy for future research.

Exercise Training Attenuates Cardiac Vulnerability and Promotes Cardiac Resistance to Isoproterenol-Induced Injury Following Hookah Smoke Inhalation in Male Rats: Role of Klotho and Sirtuins

Hookah smoking is on the rise around the world. Present study investigated the heart resistance to harmful stress following long-term waterpipe tobacco smoking (WTS) and moderate-intensity exercise training intervention in male Wistar rats. Animals were randomly divided into a non-ischemic heart control group and four ischemic heart groups including ISO (isoproterenol-treated), Ex + ISO (subjected to exercise plus ISO), S + ISO (exposed to hookah smoke plus ISO), and Ex + S + ISO (subjected to exercise along with hookah smoke plus ISO). After eight weeks of training and WTS, heart ischemia induced by isoproterenol injections. Then, cardiac functional indices and some biochemical and histopathological parameters were assessed. WTS + ISO reduced systolic pressure, ± dP/dt max, and contractility indices (P < 0.001 vs. ISO group) and increased end diastolic pressure and Tau index (P < 0.001 vs. ISO) of the left ventricle. Also, WTS + ISO was associated with an increase in Bax protein level and Bax/Bcl-2 ratio (P < 0.05 and P < 001, respectively, vs. ISO group) as apoptotic markers of heart tissue. Hookah smoke significantly decreased SIRT1 (P < 0.05 and P < 0.001, respectively, vs. ISO) and klotho (P < 0.01 and P < 0.001, respectively, vs. ISO) in serum and heart, and SIRT3 and pS9-GSK-3β (P < 001 and P < 0.05, respectively, vs. ISO) in heart tissue. Combination of exercise with WTS prevented the hookah smoke-induced alterations in apoptotic markers, cardiac functional indices, and SIRT1, SIRT3, klotho, and pS9-GSK-3β proteins. The findings demonstrated that hookah smoke inhalation intensifies ventricular dysfunction and decreases heart resistance to harmful stresses. Moderate-intensity exercise training attenuated these complications partly through recovering the klotho and sirtuins levels and apoptosis-survival balancing.

Endothelial SIRT1 as a Target for the Prevention of Arterial Aging: Promises and Challenges

ABSTRACT

SIRT1, a member of the sirtuin family of longevity regulators, possesses potent activities preventing vascular aging. The expression and function of SIRT1 in endothelial cells are downregulated with age, in turn causing early vascular aging and predisposing various vascular abnormalities. Overexpression of SIRT1 in the vascular endothelium prevents aging-associated endothelial dysfunction and senescence, thus the development of hypertension and atherosclerosis. Numerous efforts have been directed to increase SIRT1 signaling as a potential strategy for different aging-associated diseases. However, the complex mechanisms underlying the regulation of SIRT1 have posed a significant challenge toward the design of specific and effective therapeutics. This review aimed to provide a summary on the regulation and function of SIRT1 in the vascular endothelium and to discuss the different approaches targeting this molecule for the prevention and treatment of age-related cardiovascular and cerebrovascular diseases.

Sirtuin 1 in Endothelial Dysfunction and Cardiovascular Aging

Sirtuin 1 (SIRT1) is a histone deacetylase belonging to the family of Sirtuins, a class of nicotinamide adenine dinucleotide (NAD+)-dependent enzymes with multiple metabolic functions. SIRT1 localizes in the nucleus and cytoplasm, and is implicated in the regulation of cell survival in response to several stimuli, including metabolic ones. The expression of SIRT1 is associated with lifespan and is reduced with aging both in animal models and in humans, where the lack of SIRT1 is regarded as a potential mediator of age-related cardiovascular diseases. In this review, we will summarize the extensive evidence linking SIRT1 functional and quantitative defects to cellular senescence and aging, with particular regard to their role in determining endothelial dysfunction and consequent cardiovascular diseases. Ultimately, we outline the translational perspectives for this topic, in order to highlight the missing evidence and the future research steps.

Involvement of Sirtuins and Klotho in Cardioprotective Effects of Exercise Training Against Waterpipe Tobacco Smoking-Induced Heart Dysfunction

Despite its negative effect on the cardiovascular system, waterpipe smoking (WPS) is currently popular worldwide, especially among youth. This study investigated the effects of moderate endurance exercise on heart function of rats exposed to WPS and its possible mechanism. The animals were randomly divided into four groups: control group (CTL), the exercise group (Ex) which trained for 8 weeks, the waterpipe tobacco smoking group (S) exposed to smoke inhalation (30 min per day, 5 days each week, for 8 weeks), and the group that did exercise training and received waterpipe tobacco smoke inhalation together (Ex + S). One day after the last session of Ex and WPS, cardiac pressures and functional indices were recorded and calculated. The levels of SIRT1, SIRT3, Klotho, Bax, and Bcl-2 in the serum and heart, the expression of phosphorylated GSK3β of heart tissue, and cardiac histopathological changes were assessed. WPS reduced systolic pressure, +dP/dt max, -dP/dt max, and heart contractility indices (P < 0.001 vs. CTL) and increased cardiac tissue lesions (P < 0.05 vs. CTL) and end diastolic pressure and Tau index (P < 0.001 vs. CTL) of the left ventricle. Exercise training normalized the left ventricular end diastolic pressure, +dP/dt max, and contractility index. Also, exercise improved the levels of SIRT1, SIRT3, Klotho, and Bcl-2 and reduced Bax level in the heart. The findings showed that WPS causes left ventricular dysfunction. Moderate exercise prevented WPS-induced heart dysfunction partly through its anti-apoptotic features and activation of the sirtuins and Klotho pathways.

Skeletal Muscle Gene Expression Profile in Response to Caloric Restriction and Aging: A Role for SirT1

SirT1 plays a crucial role in the regulation of some of the caloric restriction (CR) responsive biological pathways. Aging suppresses SirT1 gene expression in skeletal muscle, suggesting that aging may affect the role of CR in muscle. To determine the role of SirT1 in the regulation of CR regulated pathways in skeletal muscle, we performed high-throughput RNA sequencing using total RNA isolated from the skeletal muscles of young and aged wild-type (WT), SirT1 knockout (SirT1-KO), and SirT1 overexpression (SirT1-OE) mice fed to 20 wk ad libitum (AL) or 40% CR diet. Our data show that aging repressed the global gene expression profile, which was restored by CR via upregulating transcriptional and translational process-related pathways. CR inhibits pathways linked to the extracellular matrix and cytoskeletal proteins regardless of aging. Mitochondrial function and muscle contraction-related pathways are upregulated in aged SirT1 KO mice following CR. SirT1 OE did not affect whole-body energy expenditure or augment skeletal muscle insulin sensitivity associated pathways, regardless of aging or diet. Overall, our RNA-seq data showed that SirT1 and CR have different functions and activation of SirT1 by its activator or exercise may enhance SirT1 activity that, along with CR, likely have a better functional role in aging muscle.

Predictive Value of Sirtuins in Acute Myocardial Infarction - Bridging the Bench to the Clinical Practice

Acute myocardial infarction (AMI) is a non-transmissible condition with high prevalence, morbidity, and mortality. Different strategies for the management of AMI are employed worldwide, but its early diagnosis remains a major challenge. Many molecules have been proposed in recent years as predictive agents in the early detection of AMI, including troponin (C, T, and I), creatine kinase MB isoenzyme, myoglobin, heart-type fatty acid-binding protein, and a family of histone deacetylases with enzymatic activities named sirtuins. Sirtuins may be used as predictive or complementary treatment strategies and the results of recent preclinical studies are promising. However, human clinical trials and data are scarce, and many issues have been raised regarding the predictive values of sirtuins. The present review summarizes research on the predictive value of sirtuins in AMI. We also briefly summarize relevant clinical trials and discuss future perspectives and possible clinical applications.

SIRT1 is Required for Exercise-Induced Beneficial Effects on Myocardial Ischemia/Reperfusion Injury

Background

Exercise training has been regarded as an effective mean of prevention and treatment of cardiovascular diseases (CVD), and exercise can improve the antioxidant capacity of the myocardial. While SIRT1 has been proved to protects the heart from myocardial ischemia/reperfusion (MI/R) injury and apoptosis, less is known about the association between exercise-induced cardioprotection and SIRT1.

Methods and Results

MI/R injury model was constructed after swimming training in mice. Significantly reduced myocardial infarct size, decreased apoptosis ratio and upregulated SIRT1 protein expression in heart were found in swam mice by 2,3,5-triphenyltetrazolium chloride (TTC) staining of heart sections, TUNEL staining of frozen sections and Western blotting. The results of TUNEL staining and Western blotting suggested activation of SIRT1 using resveratrol (RSV) or inhibition of SIRT1 using EX527 in vitro blocked or accelerated cardiomyocytes apoptosis which induced by hypoxia/reoxygenation (H/R) respectively and regulated the expression of antioxidants in vitro. PGC-1α has been identified as one of the downstream genes of SIRT1 modulating oxidative stress and apoptosis. Importantly, the data of TTC staining, TUNEL staining, Western blotting, echocardiography and histopathological staining revealed that mice with inducible cardiac SIRT1-knockout blocked the protective effects of exercise preconditioning on myocardial infarct size, myocardial apoptosis, adverse ventricular remodeling, cardiac fibrosis and cardiac dysfunction after MI/R injury, simultaneously exercise-induced expression of myocardial antioxidant stress factors was hindered which was detected by immunohistochemical analysis.

Conclusion

SIRT1 protects against oxidative stress after MI/R injury by activating downstream PGC-1α and promoting the production of antioxidant enzymes. SIRT1 is required for exercise to protect against myocardial apoptosis and maladaptive ventricular remodelling induced by myocardial ischemia/reperfusion injury.

Biomarkers of ageing and cardiac remodeling are associated with atrial fibrillation

Objectives. Ageing is one of the strongest risk factors for atrial fibrillation (AF), and additional risk factors are also closely related to ageing. Remodeling is part of the pathophysiology of AF, and a possible common denominator of ageing and other AF risk factors. The aim of this study was to investigate any association between the presence of AF and the ageing biomarkers, leukocyte telomere length (LTL) and sirtuin-1 (SIRT-1), and the cardiac remodeling biomarkers Galectin-3 and sST2 in elderly myocardial infarction (MI) patients. Design. Patients were included after admission for MI. Diagnosis of AF was retrieved from medical records and classified as either history of AF before MI or new onset from admission to study inclusion. SIRT-1, sST2 and Galectin-3 were analyzed by ELISAs and LTL by qPCR. Results. In total, 299 patients were included, median age 75 years, 70.2% male. A history of AF was recorded in 38 patients and 30 patients experienced new onset AF. Higher levels of SIRT-1 were associated with lower risk of having a history of AF (OR = 0.46 (95% CI 0.26, 0.81), p = 0.007), whereas higher sST2 levels were associated with higher risk of AF (OR = 4.13 (95% CI 1.69, 10.13), p = 0.002). Results remained significant after adjustment for other AF risk factors. No significant associations with AF were found for Galectin-3 or LTL. None of the biomarkers associated with new onset AF. Conclusion. In elderly patients with MI, higher ST2 and lower SIRT-2 levels were associated with higher prevalence of AF, possibly reflecting both ageing and the remodeling phenomena in AF. Clinical trials registration: ClinicalTrials.gov (NCT01841944).

Polysulfide-mediated sulfhydration of SIRT1 prevents diabetic nephropathy by suppressing phosphorylation and acetylation of p65 NF-κB and STAT3

Diabetic kidney disease is known as a major cause of chronic kidney disease and end stage renal disease. Polysulfides, a class of chemical agents with a chain of sulfur atoms, are found to confer renal protective effects in acute kidney injury. However, whether a polysulfide donor, sodium tetrasulfide (Na₂S₄), confers protective effects against diabetic nephropathy remains unclear. Our results showed that Na₂S₄ treatment ameliorated renal dysfunctional and histological damage in diabetic kidneys through inhibiting the overproduction of inflammation cytokine and reactive oxygen species (ROS), as well as attenuating renal fibrosis and renal cell apoptosis. Additionally, the upregulated phosphorylation and acetylation levels of p65 nuclear factor κB (p65 NF-κB) and signal transducer and activator of transcription 3 (STAT3) in diabetic nephropathy were abrogated by Na₂S₄ in a sirtuin-1 (SIRT1)-dependent manner. In renal tubular epithelial cells, Na₂S₄ directly sulfhydrated SIRT1 at two conserved CXXC domains (Cys371/374; Cys395/398), then induced dephosphorylation and deacetylation of its targeted proteins including p65 NF-κB and STAT3, thereby reducing high glucose (HG)-caused oxidative stress, cell apoptosis, inflammation response and epithelial-to-mesenchymal transition (EMT) progression. Most importantly, inactivation of SIRT1 by a specific inhibitor EX-527, small interfering RNA (siRNA), a de-sulfhydration reagent dithiothreitol (DTT), or mutation of Cys371/374 and Cys395/398 sites at SIRT1 abolished the protective effects of Na₂S₄ on diabetic kidney insulting. These results reveal that polysulfides may attenuate diabetic renal lesions via inactivation of p65 NF-κB and STAT3 phosphorylation/acetylation through sulfhydrating SIRT1.

Nutrients and Pathways that Regulate Health Span and Life Span

Both life span and health span are influenced by genetic, environmental and lifestyle factors. With the genetic influence on human life span estimated to be about 20–25%, epigenetic changes play an important role in modulating individual health status and aging. Thus, a main part of life expectance and healthy aging is determined by dietary habits and nutritional factors. Excessive or restricted food consumption have direct effects on health status. Moreover, some dietary interventions including a reduced intake of dietary calories without malnutrition, or a restriction of specific dietary component may promote health benefits and decrease the incidence of aging-related comorbidities, thus representing intriguing potential approaches to improve healthy aging. However, the relationship between nutrition, health and aging is still not fully understood as well as the mechanisms by which nutrients and nutritional status may affect health span and longevity in model organisms. The broad effect of different nutritional conditions on health span and longevity occurs through multiple mechanisms that involve evolutionary conserved nutrient-sensing pathways in tissues and organs. These pathways interacting each other include the evolutionary conserved key regulators mammalian target of rapamycin, AMP-activated protein kinase, insulin/insulin-like growth factor 1 pathway and sirtuins. In this review we provide a summary of the main molecular mechanisms by which different nutritional conditions, i.e., specific nutrient abundance or restriction, may affect health span and life span.

Exercise Training and Vitamin C Supplementation Affects Ferritin mRNA in Leukocytes without Affecting Prooxidative/Antioxidative Balance in Elderly Women

Physical training and antioxidant supplementation may influence iron metabolism through reduced oxidative stress and subsequent lowering of mRNA levels of genes that are easily induced by this stress, including those responsible for iron homeostasis. Fifteen elderly women participated in our 12-week experiment, involving six weeks of training without supplementation and six weeks of training supported by oral supplementation of 1000 mg of vitamin C daily. The participants were divided into two groups (n = 7 in group 1 and n = 8 in group 2). In group 1, we applied vitamin C supplementation in the first six weeks of training, while in group 2 during the remaining six weeks of training. In both phases, the health-related training occurred three times per week. Training accompanied by vitamin C supplementation did not affect prooxidative/antioxidative balance but significantly decreased ferritin heavy chain (FTH) and ferritin light chain (FTL) mRNA in leukocytes (for FTH mRNA from 2^64.24 to 2^11.06, p = 0.03 in group 1 and from 2^60.54 to 2^16.03, p = 0.01 in group 2, for FTL mRNA from 2^20.22 to 2^4.53, p = 0.01 in group 2). We concluded that vitamin C supplementation might have caused a decrease in gene expression of two important antioxidative genes (FTH, FTL) and had no effect on plasma prooxidative/antioxidative balance.

SIRT1 Activation by Natural Phytochemicals: An Overview

Sirtuins are class III histone deacetylases, whose enzymatic activity is dependent on NAD⁺ as a cofactor. Sirtuins are reported to modulate numerous activities by controlling gene expression, DNA repair, metabolism, oxidative stress response, mitochondrial function, and biogenesis. Deregulation of their expression and/or action may lead to tissue-specific degenerative events involved in the development of several human pathologies, including cancer, neurodegeneration, and cardiovascular disease. The most studied member of this class of enzymes is sirtuin 1 (SIRT1), whose expression is associated with increasing insulin sensitivity. SIRT1 has been implicated in both tumorigenic and anticancer processes, and is reported to regulate essential metabolic pathways, suggesting that its activation might be beneficial against disorders of the metabolism. Via regulation of p53 deacetylation and modulation of autophagy, SIRT1 is implicated in cellular response to caloric restriction and lifespan extension. In recent years, scientific interest focusing on the identification of SIRT1 modulators has led to the discovery of novel small molecules targeting SIRT1 activity. This review will examine compounds of natural origin recently found to upregulate SIRT1 activity, such as polyphenolic products in fruits, vegetables, and plants including resveratrol, fisetin, quercetin, and curcumin. We will also discuss the potential therapeutic effects of these natural compounds in the prevention and treatment of human disorders, with particular emphasis on their metabolic impact.

Influence of the maternal high-intensity-interval-training on the cardiac Sirt6 and lipid profile of the adult male offspring in rats

The susceptibility to cardiovascular disease in offspring could be reduced prior to birth through maternal intervention, before and during pregnancy. We evaluated whether the initiation periods of maternal exercise in preconception and pregnancy periods induce beneficial effects in the adult male offspring. Thirty-two female rats were divided into control and exercise groups. The exercise groups involve exercise before pregnancy or the preconception periods, exercise during pregnancy, and exercise before and during pregnancy. The mothers in the exercise groups were run on the treadmill in different periods. Then the birth weight and weekly weight gain of male offspring were measured, and the blood and left ventricle tissue of samples were collected for analysis of the Sirtuin 6 (Sirt6) and insulin growth factor-2 (IGF-2) gene expression, serum levels of low-density lipoprotein (LDL), high-density lipoprotein (HDL), cholesterol (Cho), and triglycerides (TG). There was no significant difference in the birth weight of offspring groups (P = 0.246) while maternal HIIT only during pregnancy leads to reduce weekly weight gain of offspring. Our data showed that Sirt6 and IGF-2 gene expression was increased (P = 0.017) and decreased (P = 0.047) by maternal exercise prior to and during pregnancy, respectively. Also, the serum level of LDL (p = 0.002) and Cho (P = 0.007) were significantly decreased and maternal exercise leads to improves the running speed of the adult male offspring (p = 0.0176). This study suggests that maternal HIIT prior to and during pregnancy have positive intergenerational consequence in the health and physical readiness of offspring.

Impact of Modality and Intensity of Early Exercise Training on Ventricular Remodeling after Myocardial Infarction

The objective of this study was to analyze the impact of different modalities and intensities of exercise training on cardiac remodeling started early after experimental myocardial infarction (MI). Male Wistar rats, weighing 200-250 g, were subjected to experimental MI. After 5 days, the animals were allocated into three experimental groups and observed for three months: S (sedentary control animals), C (animals subjected to continuous low-intensity training), and HIT (animals subjected to high-intensity interval training). Low-intensity exercise training was performed at a treadmill speed corresponding to 40% VO₂ max, which was kept unchanged throughout the entire session (i.e., continuous low-intensity training). High-intensity interval training was performed in such a way that rats run during 3 min at 60% VO₂ max, followed by 4-minute intervals at 85% VO₂ max (i.e., high-intensity interval training). After the follow-up period, we studied hypertrophy and ventricular geometry, functional alterations in vivo and in vitro, oxidative stress, apoptosis, and cardiac energetic metabolism. Our data showed that both high-intensity interval and continuous low-intensity modalities improved cardiac energetic metabolism variables in comparison with sedentary infarcted animals. In addition, high-intensity interval training decreased cardiac oxidative stress, associated with improved diastolic function. On the other hand, the continuous low-intensity group showed impairment of cardiac function. Therefore, altogether, our data suggest that high-intensity interval training could be the best modality for early physical exercise after MI and should be better studied in this clinical scenario.

Post-translational Modification Crosstalk and Hotspots in Sirtuin Interactors Implicated in Cardiovascular Diseases

Sirtuins are protein deacetylases that play a protective role in cardiovascular diseases (CVDs), as well as many other diseases. Absence of sirtuins can lead to hyperacetylation of both nuclear and mitochondrial proteins leading to metabolic dysregulation. The protein post-translational modifications (PTMs) are known to crosstalk among each other to bring about complex phenotypic outcomes. Various PTM types such as acetylation, ubiquitination, and phosphorylation, and so on, drive transcriptional regulation and metabolism, but such crosstalks are poorly understood. We integrated protein–protein interactions (PPI) and PTMs from several databases to integrate information on 1,251 sirtuin-interacting proteins, of which 544 are associated with cardiac diseases. Based on the ∼100,000 PTM sites obtained for sirtuin interactors, we observed that the frequency of PTM sites (83 per protein), as well as PTM types (five per protein), is higher than the global average for human proteome. We found that ∼60–70% PTM sites fall into ordered regions. Approximately 83% of the sirtuin interactors contained at least one competitive crosstalk (in situ) site, with half of the sites occurring in CVD-associated proteins. A large proportion of identified crosstalk sites were observed for acetylation and ubiquitination competition. We identified 614 proteins containing PTM hotspots (≥5 PTM sites) and 133 proteins containing crosstalk hotspots (≥3 crosstalk sites). We observed that a large proportion of disease-associated sequence variants were found in PTM motifs of CVD proteins. We identified seven proteins (TP53, LMNA, MAPT, ATP2A2, NCL, APEX1, and HIST1H3A) containing disease-associated variants in PTM and crosstalk hotspots. This is the first comprehensive bioinformatics analysis on sirtuin interactors with respect to PTMs and their crosstalks. This study forms a platform for generating interesting hypotheses that can be tested for a deeper mechanistic understanding gained or derived from big-data analytics.

The systemic role of SIRT1 in exercise mediated adaptation

Cellular energy demands are readily changed during physical exercise resulting in adaptive responses by signaling proteins of metabolic processes, including the NAD⁺ dependent lysine deacetylase SIRT1. Regular exercise results in systemic adaptation that restores the level of SIRT1 in the kidney, liver, and brain in patients with neurodegenerative diseases, and thereby normalizes cellular metabolic processes to attenuate the severity of these diseases. In skeletal muscle, over-expression of SIRT1 results in enhanced numbers of myonuclei improves the repair process after injury and is actively involved in muscle hypertrophy by up-regulating anabolic and downregulating catabolic processes. The present review discusses the different views of SIRT1 dependent deacetylation of PGC-α.

Proposed Tandem Effect of Physical Activity and Sirtuin 1 and 3 Activation in Regulating Glucose Homeostasis

Sirtuins (SIRTs) are seven nicotinamide adenine dinucleotide (NAD⁺)-dependent protein deacetylases enzymes (SIRT1–7) that play an important role in maintaining cellular homeostasis. Among those, the most studied are SIRT1 and SIRT3, a nuclear SIRT and a mitochondrial SIRT, respectively, which significantly impact with an increase in mammals’ lifespan by modulating metabolic cellular processes. Particularly, when activated, both SIRT1 and 3 enhance pancreatic β-cells’ insulin release and reduce inflammation and oxidative stress pancreatic damage, maintaining then glucose homeostasis. Therefore, SIRT1 and 3 activators have been proposed to prevent and counteract metabolic age-related diseases, such as type 2 diabetes mellitus (T2DM). Physical activity (PA) has a well-established beneficial effect on phenotypes of aging like β-cell dysfunction and diabetes mellitus. Recent experimental and clinical evidence reports that PA increases the expression levels of both SIRT1 and 3, suggesting that PA may exert its healthy contribute even by activating SIRTs. Therefore, in the present article, we discuss the role of SIRT1, SIRT3, and PA on β-cell function and on diabetes. We also discuss the possible interaction between PA and activation of SIRTs as a possible therapeutic strategy to maintain glucose hemostasis and to prevent T2DM and its complications, especially in the elderly population.