Resveratrol ameliorates endothelial dysfunction in diabetic and obese mice through sirtuin 1 and peroxisome proliferator-activated receptor δ

Resveratrol improves gasdermin D-mediated pyroptosis of vascular endothelial cells induced by a high-fat diet and palmitic acid possibly via the SIRT1-p66Shc-NLRP3 pathway

Resveratrol (RSV) ameliorates endothelial dysfunction (ED) primarily through sirtuin 1 (SIRT1). Increasing evidence shows pyroptosis as a novel mechanism in palmitic acid (PA)-induced ED. p66Shc is an adaptor protein involved in oxidative stress. However, whether RSV attenuates the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome via p66Shc remains elusive. This study aims to evaluate whether the antipyroptotic effect of RSV and the SIRT1 inhibitor EX527 are related to p66Shc. High-fat diet (HFD) induced obesity in mice, and RSV was administered intragastrically with 400mg/kg/d for 22 successive weeks. The serum levels of interleukin-1β (IL-1β) and IL-18 were analyzed, and the expression of related proteins were assayed with immunohistochemistry in the thoracic aorta. human umbilical vein endothelial cells (HUVECs) were induced by PA, then treated with RSV and EX527 respectively, lactate dehydrogenase (LDH) release, reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP) and expression of p66Shc, NLRP3, GSDMD and pyroptosis-related genes were assayed. RSV administration ameliorated endothelial cell pyroptosis by decreasing serum IL-1β and IL-18, the expression of NLRP3, p66Shc, and gasdermin D (GSDMD), and increasing the expression of SIRT1 in the HFD-treated thoracic aorta. PA promoted GSDMD-mediated endothelial cell pyroptosis by ROS production, LDH release, decreased MMP and SIRT1 expression, increased expression of p66Shc and activation of the NLRP3 inflammasome in a dose-dependent manner. RSV attenuated PA-induced pyroptosis, whereas EX527 reversed the antipyroptotic effect of RSV in PA-treated HUVECs. Our results suggested a new mechanism that RSV improves PA-induced pyroptosis in endothelial cells via the SIRT1-p66Shc-NLRP3 pathway.

Regulatory effects of resveratrol on nitric oxide signaling in cardiovascular diseases

Cardiovascular illnesses are multifactorial disorders and represent the primary reasons for death worldwide, according to the World Health Organization. As a signaling molecule, nitric oxide (NO) is extremely permeable across cellular membranes owing to its unique molecular features, like its small molecular size, lipophilicity, and free radical properties. Some of the biological effects of NO are vasodilation, inhibition in the growth of vascular smooth muscle cells, and functional regulation of cardiac cells. Several therapeutic approaches have been tested to increase the production of NO or some downstream NO signaling pathways. The health benefits of red wine are typically attributed to the polyphenolic phytoalexin, resveratrol (3,5,4'-trihydroxy-trans-stilbene), which is found in several plant species. Resveratrol has beneficial cardiovascular properties, some of which are mediated through endothelial nitric oxide synthase production (eNOS). Resveratrol promotes NO generation from eNOS through various methods, including upregulation of eNOS expression, activation in the enzymatic activity of eNOS, and reversal of eNOS uncoupling. Additionally, by reducing of oxidative stress, resveratrol inhibits the formation of superoxide and inactivation NO, increasing NO bioavailability. This review discusses the scientific literature on resveratrol's beneficial impact on NO signaling and how this effect improves the function of vascular endothelium.

Beneficial effects of resveratrol on diabetes mellitus and its complications: focus on mechanisms of action

Diabetes mellitus (DM) is a significant global health issue, associated with various microvascular and macrovascular complications that significantly impair patients' quality of life as well as healthspan and lifespan. Despite the availability of several anti-diabetic medications with different mechanisms of action, there remains no definite curative treatment. Hence, discovering new efficient complementary therapies is essential. Natural products have received significant attention due to their advantages in various pathological conditions. Resveratrol is a natural polyphenol that possesses antioxidant and anti-inflammatory properties, and its efficacy has been previously investigated in several diseases, including DM. Herein, we aimed to provide a holistic view of the signaling pathways and mechanisms of action through which resveratrol exerts its effects against DM and its complications.

Isorhamnetin as a potential therapeutic agent for diabetes mellitus through PGK1/AKT activation

CONTEXT

Type 2 Diabetes Mellitus (T2D) is a significant health concern worldwide, necessitating novel therapeutic approaches beyond conventional treatments.

OBJECTIVE

To assess isorhamnetin's potential in improving insulin sensitivity and mitigating T2D characteristics through oxidative and glycative stress modulation.

MATERIALS AND METHODS

T2D was induced in mice with a high-fat diet and streptozotocin injections. Isorhamnetin was administered at 10 mg/kg for 12 weeks. HepG2 cells were used to examine in vitro effects on stress markers and insulin sensitivity. Molecular effects on the PGK1 and AKT signalling pathway were also analyzed.

RESULTS

The administration of isorhamnetin significantly impacted both in vivo and in vitro models. In HepG2 cells, oxidative and glycative stresses were markedly reduced, indicating a direct effect of isorhamnetin on cellular stress pathways, which are implicated in the deterioration of insulin sensitivity. Specifically, treated cells showed a notable decrease in markers of oxidative stress, such as malondialdehyde, and advanced glycation end products, highlighting isorhamnetin's antioxidant and antiglycative properties. In vivo, isorhamnetin-treated mice exhibited substantially lower fasting glucose levels compared to untreated T2D mice, suggesting a strong hypoglycemic effect. Moreover, these mice showed improved insulin responsiveness, evidenced by enhanced glucose tolerance and insulin tolerance tests. The molecular investigation revealed that isorhamnetin activated PGK1, leading to the activation of the AKT signalling pathway, crucial for promoting glucose uptake and reducing insulin resistance. This molecular action underscores the potential mechanism through which isorhamnetin exerts its beneficial effects in T2D management.

DISCUSSION

The study underscores isorhamnetin's multifaceted role in T2D management, emphasizing its impact on oxidative and glycative stress reduction and molecular pathways critical for insulin sensitivity.

CONCLUSION

Isorhamnetin presents a promising avenue for T2D treatment, offering a novel approach to enhancing insulin sensitivity and managing glucose levels through the modulation of key molecular pathways. Further research is needed to translate these findings into clinical practice.

Cellular Senescence: A Bridge Between Diabetes and Microangiopathy

Cellular senescence is a state of permanent cell cycle arrest and plays an important role in many vascular lesions. This study found that the cells of diabetic patients have more characteristics of senescence, which may cause microvascular complications. Cell senescence, as one of the common fates of cells, links microangiopathy and diabetes. Cell senescence in a high-glucose environment can partially elucidate the mechanism of diabetic microangiopathy, and various types of cellular senescence induced by it can promote the progression of diabetic microangiopathy. Still, the molecular mechanism of microangiopathy-related cellular senescence has not yet been clearly studied. Building on recent research evidence, we herein summarize the fundamental mechanisms underlying the development of cellular senescence in various microangiopathies associated with diabetes. We gradually explain how cellular senescence serves as a key driver of diabetic microangiopathy. At the same time, the treatment of basic senescence mechanisms such as cellular senescence may have a great impact on the pathogenesis of the disease, may be more effective in preventing the development of diabetic microangiopathy, and may provide new ideas for the clinical treatment and prognosis of diabetic microangiopathy.

3,3',4,5'-Tetramethoxy-trans-stilbene and 3,4',5-trimethoxy-trans-stilbene prevent oxygen-glucose deprivation-induced injury in brain endothelial cell

Blood-brain barrier (BBB) disruption is a major pathophysiological event of ischemic stroke. Brain microvascular endothelial cells are critical to maintain homeostasis between central nervous system and periphery. Resveratrol protects against ischemic stroke. 3,3',4,5'-tetramethoxy-trans-stilbene (3,3',4,5'-TMS) and 3,4',5-trimethoxy-trans-stilbene (3,4',5-TMS) are resveratrol derivatives with addition of methoxy groups, showing better pharmacokinetic performance. We aimed to explore their protective effects and underlying mechanisms. Oxygen-glucose deprivation (OGD) model was applied in bEnd.3 cell line, mouse brain microvascular endothelium to mimic ischemia. The cells were pre-treated with 3,3',4,5'-TMS or 3,4',5-TMS (1 and 5 μM, 24 h) and then subjected to 2-h OGD injury. Cell viability, levels of proinflammatory cytokines and reactive oxygen species (ROS), and protein expressions were measured by molecular assays and fluorescence staining. OGD injury triggered cell death, inflammatory responses, ROS production and nuclear factor-kappa B (NF-κB) signalling pathway. These impairments were remarkably attenuated by the two stilbenes, 3,3',4,5'-TMS and 3,4',5-TMS. They also alleviated endothelial barrier injuries through upregulating the expression of tight junction proteins. Moreover, 3,3',4,5'-TMS and 3,4',5-TMS activated 5' adenosine monophosphate-activated protein kinase (AMPK) and endothelial nitric oxide synthase (eNOS). Overall, 3,3',4,5'-TMS and 3,4',5-TMS exert protective effects against OGD damage through suppressing cell death, inflammatory responses, oxidative stress, as well as BBB disruption on bEnd.3 cells.

The anti-obesity effects of resveratrol on the 3T3-L1 adipocytes

Obesity is a severe health problem worldwide due to its association with various adverse health consequences. The present study aims to evaluate the anti-obesity effects of resveratrol, as a natural polyphenol, on the 3T3-L1 adipocytes. PubMed, Scopus, ScienceDirect, Web of Sciences, and Google Scholar databases were searched up to March 2022 using relevant keywords. All original articles, written in English, evaluating the anti-obesity effects of resveratrol on the 3T3-L1 adipocytes were eligible for this review. Initially, 4361 records were found in the electronic search databases. After removing duplicates and irrelevant studies according to the title and abstract, the full text of the 51 articles was critically screened and 38 in vitro studies were included in this review. Except for one case, all of these studies reported that different doses (ranged 1-200 μM) of resveratrol treatment have anti-obesity effects on 3T3L1 adipocytes through various mechanisms such as induction of apoptosis, a decrease of fat accumulation and adipogenesis, promotion of white adipocytes browning, inhibition of preadipocyte proliferation and consequent differentiation, and up-regulation of miRNA that involved in the antiadipogenic and triacylglycerol metabolism in white adipose tissue. The findings indicate that resveratrol has anti-obesity effects. Therefore, resveratrol treatment could be used to prevent and treat obesity and its related disorders. Well-designed randomized clinical trials with different doses of resveratrol are recommended to be performed on obese subjects.

Ginsenoside Rk1 improves endothelial function in diabetes through activating peroxisome proliferator-activated receptors

Ginsenoside Rk1, one kind of ginsenoside, is a minor ginsenoside found in Panax ginseng and used as traditional Chinese medicine for centuries. It exhibits anti-tumor and anti-aggregation effects. However, little research has been done on its effect on endothelial function. This study investigated whether ginsenoside Rk1 improved endothelial dysfunction in diabetes and the underlying mechanisms in vivo and in vitro. Male C57BL/6 mice were fed with a 12 week high-fat diet (60% kcal % fat), whereas treatment groups were orally administered with ginsenoside Rk1 (10 and 20 mg per kg per day) in the last 4 weeks. Aortas isolated from C57BL/6 mice were induced by high glucose (HG; 30 mM) and co-treated with or without ginsenoside Rk1 (1 and 10 μM) for 48 h ex vivo. Moreover, primary rat aortic endothelial cells (RAECs) were cultured and stimulated by HG (44 mM) to mimic hyperglycemia, with or without the co-treatment of ginsenoside Rk1 (10 μM) for 48 h. Endothelium-dependent relaxations of mouse aortas were damaged with elevated oxidative stress and downregulation of three isoforms of peroxisome proliferator-activated receptors (PPARs), PPAR-α, PPAR-β/δ, and PPAR-γ, as well as endothelial nitric oxide synthase (eNOS) phosphorylation due to HG or high-fat diet stimulation, which also existed in RAECs. However, after the treatment with ginsenoside Rk1, these impairments were all ameliorated significantly. Moreover, the vaso-protective and anti-oxidative effects of ginsenoside Rk1 were abolished by PPAR antagonists (GSK0660, GW9662 or GW6471). In conclusion, this study reveals that ginsenoside Rk1 ameliorates endothelial dysfunction and suppresses oxidative stress in diabetic vasculature through activating the PPAR/eNOS pathway.

3,4',5-Trimethoxy-trans-stilbene ameliorates hepatic insulin resistance and oxidative stress in diabetic obese mice through insulin and Nrf2 signaling pathways

Resveratrol has profound benefits against diabetes. However, whether its methylated derivative 3,4',5-trimethoxy-trans-stilbene (3,4',5-TMS) also plays a protective role in glucose metabolism is not characterized. We aimed to study the anti-diabetic effects of 3,4',5-TMS in vitro and in vivo. Insulin-resistant HepG2 cells (IR-HepG2) were induced by high glucose plus dexamethasone whilst six-week-old male C57BL/6J mice received a 60 kcal% fat diet for 14 weeks to establish an obese diabetic model. 3,4',5-TMS did not reduce the cell viability of IR-HepG2 cells at concentrations of 0.5 and 1 μM, which enhanced the capability of glycogen synthesis and glucose consumption in IR-HepG2 cells. Four-week oral administration of 3,4',5-TMS at 10 mg kg-1 day-1 ameliorated insulin sensitivity and glucose tolerance of diet-induced obese (DIO) mice. 3,4',5-TMS activated the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway by inhibiting phosphorylation of insulin receptor substrate (IRS)-1 at Ser307 and increasing the protein levels of IRS-1 and IRS-2 to restore the insulin signaling pathway in diabetes. 3,4',5-TMS also upregulated the phosphorylation of glycogen synthase kinase 3 beta (GSK3β) at Ser9. 3,4',5-TMS suppressed oxidative stress by increasing the protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and NAD(P)H : quinone oxidoreductase 1 (NQO1) and antioxidant enzyme activity. In summary, 3,4',5-TMS alleviated hepatic insulin resistance in vitro and in vivo, by the activation of the insulin signaling pathway, accomplished by the suppression of oxidative stress.

SIRT1 and thrombosis

Thrombosis is a major cause of morbidity and mortality worldwide, with a complex and multifactorial pathogenesis. Recent studies have shown that SIRT1, a member of the sirtuin family of NAD + -dependent deacetylases, plays a crucial role in regulating thrombosis, modulating key pathways including endothelial activation, platelet aggregation, and coagulation. Furthermore, SIRT1 displays anti-inflammatory activity both in vitro, in vivo and in clinical studies, particularly via the reduction of oxidative stress. On these bases, several studies have investigated the therapeutic potential of targeting SIRT1 for the prevention of thrombosis. This review provides a comprehensive and critical overview of the main preclinical and clinical studies and of the current understanding of the role of SIRT1 in thrombosis.

Natural Sirtuin1 Activators and Atherosclerosis: an Overview

PURPOSE OF REVIEW

The purpose of this review is to summarize the most recent findings investigating the impact of several natural sirtuin (SIRT) activators, particularly SIRT1, on atherosclerosis.

RECENT FINDINGS

Sirtuins that belong to a family of class III histone deacetylases are believed to be novel therapeutic targets to treat age-related and chronic diseases. SIRT expression is regulated by small molecules called SIRT-activating compounds that can be found in natural food products. SIRT1 may exert protective effects in atherosclerosis, which is said to be a major cause of cardiovascular diseases. Most of the evidence supporting the beneficial effects of these natural compounds comes from in vitro or animal-based studies, while there have been particularly few or inconsistent human-based studies evaluating their long-term impact in recent years. SIRT1 activation has been demonstrated to mitigate or prevent atherosclerosis through various mechanisms. However, further research is required to determine the optimal SIRT activator dosage and to establish a stronger correlation between health effects and the administration of bioactive compounds. Additionally, conducting more human clinical trials is necessary to ensure the safety of these compounds for preventing atherosclerosis development.

Roles of mitochondrial dynamics and mitophagy in diabetic myocardial microvascular injury

Myocardial microvessels are composed of a monolayer of endothelial cells, which play a crucial role in maintaining vascular barrier function, luminal latency, vascular tone, and myocardial perfusion. Endothelial dysfunction is a key factor in the development of cardiac microvascular injury and diabetic cardiomyopathy. In addition to their role in glucose oxidation and energy metabolism, mitochondria also participate in non-metabolic processes such as apoptosis, intracellular ion handling, and redox balancing. Mitochondrial dynamics and mitophagy are responsible for regulating the quality and quantity of mitochondria in response to hyperglycemia. However, these endogenous homeostatic mechanisms can both preserve and/or disrupt non-metabolic mitochondrial functions during diabetic endothelial damage and cardiac microvascular injury. This review provides an overview of the molecular features and regulatory mechanisms of mitochondrial dynamics and mitophagy. Furthermore, we summarize findings from various investigations that suggest abnormal mitochondrial dynamics and defective mitophagy contribute to the development of diabetic endothelial dysfunction and myocardial microvascular injury. Finally, we discuss different therapeutic strategies aimed at improving endothelial homeostasis and cardiac microvascular function through the enhancement of mitochondrial dynamics and mitophagy.

A review of the role of liposome-encapsulated phytochemicals targeting PPAR Ɣ and associated pathways to combat obesity

A limited number of studies have directly examined the effects of liposomal encapsulated phytochemicals and their anti-obesity effects in adults. This study aimed to summarize the evidence on the effect of liposomal encapsulated phytochemicals and their role in regulating major pathways involved in the anti-obesity mechanism. A systematic search was performed using several search engines like Science Direct, Google Scholar, and other online journals, focusing on laboratory research, systematic reviews, clinical trials, and meta-analysis that focused on liposomal encapsulated phytochemicals with anti-obesity properties, and followed the preferred reporting terms for this systematic review. An initial search provided a result of 1810 articles, and 93 papers were selected after the inclusion and exclusion criteria. Very few studies have been conducted on the liposomal encapsulation of phytochemicals or its synergistic study to combat obesity; hence this review paves the way for future obesity research and is mainly helpful for the pediatric obesity population. Liposomal encapsulation of phytochemicals has improved the efficiency of freely administered phytochemicals. Targeted delivery improved drug utilization and regulated the anti-obesity pathways. PPARƔ is a major therapeutic target for obesity as it inhibits adipocyte differentiation and maintains energy homeostasis.

SIRT1 Signaling Is Involved in the Vascular Improvement Induced by Moringa Oleifera Seeds during Aging

Vascular aging is linked to reduce NO bioavailability, endothelial dysfunction, oxidative stress, and inflammation. We previously showed that a 4-week treatment of middle-aged Wistar rats (MAWRs, 46 weeks old) with Moringa oleifera seed powder (MOI, 750 mg/kg/day) improved vascular function. Here, we investigated the involvement of SIRT1 in MOI-induced vascular improvement. MAWRs were treated with a standard or MOI-containing diet. Young rats (YWR, 16 weeks old) were the controls and received a standard diet. The hearts and aortas were harvested to evaluate SIRT1 and FOXO1 expression via Western blot and/or immunostaining, SIRT1 activity via a fluorometric assay, and oxidative stress using the DHE fluorescent probe. In the hearts and aortas, SIRT1 expression, reduced in MAWRs compared to YWRs, was enhanced in MOI MAWRs. In the hearts, SIRT1 activity did not differ between YWRs and MAWRs, whereas it was increased in MOI MAWRs compared with them. In the aortas, SIRT1 activity decreased in MAWRs, and it was similar in the MOI MAWRs and YWRs. FOXO1 expression increased in the nuclei of MAWR aortas compared to YWR and was reversed in MOI MAWRs. Interestingly, MOI treatment normalized oxidative stress enhanced in MAWRs, in both the heart and aorta. These results demonstrate the protective role of MOI against cardiovascular dysfunction due to aging via enhanced SIRT1 function and subsequently reduced oxidative stress.

The activation of histone deacetylases 4 prevented endothelial dysfunction: A crucial mechanism of HuangqiGuizhiWuwu Decoction in improving microcirculation dysfunction in diabetes

ETHNOPHARMACOLOGICAL RELEVANCE

The regulation of epigenetic factors is considered a crucial target for solving complex chronic diseases such as cardio-cerebrovascular diseases. HuangqiGuizhiWuwu Decoction (HGWWD), a classic Chinese prescription, is mainly used to treat various vascular diseases. Although our previous studies reported that HGWWD could effectively prevent vascular dysfunction in diabetic rodent models, the precise mechanism is still elusive.

AIM OF THE STUDY

In this study, we investigated the epigenetic mechanisms of modulating the damage of vascular endothelial cells in diabetes by HGWWD.

METHODS

We first analyzed common active components of HGWWD by using HPLC-Q-TOF-MS/MS analysis, and predicted the isoforms of histone deacetylase (HDAC) that can potentially combine the above active components by systems pharmacology. Next, we screened the involvement of specific HDAC isoforms in the protective effect of HGWWD on vascular injury by using pharmacological blockade combined with the evaluation of vascular function in vivo and in vitro.

RESULTS

Firstly, HDAC1, HDAC2, HDAC3, HDAC4, HDAC6, HDAC7, SIRT2, and SIRT3 have been implicated with the possibility of binding to the thirty-one common active components in HGWWD. Furthermore, the protective effect of HGWWD is reversed by both TSA (HDAC inhibitor) and MC1568 (class II HDAC inhibitor) on vascular impairment accompanied by reduced aortic HDAC activity in STZ mice. Finally, inhibition of HDAC4 blocked the protective effect of HGWWD on microvascular and endothelial dysfunction in diabetic mice.

CONCLUSIONS

These results prove the key role of HDAC4 in diabetes-induced microvascular dysfunction and underlying epigenetic mechanisms for the protective effect of HGWWD in diabetes.

A Potential Link Between Visceral Obesity and Risk of Alzheimer's Disease

Alzheimer's disease (AD) is the most common type of dementia characterized by the deposition of amyloid beta (Aβ) plaques and tau-neurofibrillary tangles in the brain. Visceral obesity (VO) is usually associated with low-grade inflammation due to higher expression of pro-inflammatory cytokines by adipose tissue. The objective of the present review was to evaluate the potential link between VO and the development of AD. Tissue hypoxia in obesity promotes tissue injury, production of adipocytokines, and release of pro-inflammatory cytokines leading to an oxidative-inflammatory loop with induction of insulin resistance. Importantly, brain insulin signaling is involved in the pathogenesis of AD and lower cognitive function. Obesity and enlargement of visceral adipose tissue are associated with the deposition of Aβ. All of this is consonant with VO increasing the risk of AD through the dysregulation of adipocytokines which affect the development of AD. The activated nuclear factor kappa B (NF-κB) pathway in VO might be a potential link in the development of AD. Likewise, the higher concentration of advanced glycation end-products in VO could be implicated in the pathogenesis of AD. Taken together, different inflammatory signaling pathways are activated in VO that all have a negative impact on the cognitive function and progression of AD except hypoxia-inducible factor 1 which has beneficial and neuroprotective effects in mitigating the progression of AD. In addition, VO-mediated hypoadiponectinemia and leptin resistance may promote the progression of Aβ formation and tau phosphorylation with the development of AD. In conclusion, VO-induced AD is mainly mediated through the induction of oxidative stress, inflammatory changes, leptin resistance, and hypoadiponectinemia that collectively trigger Aβ formation and neuroinflammation. Thus, early recognition of VO by visceral adiposity index with appropriate management could be a preventive measure against the development of AD in patients with VO.

Anti-aging effects of dietary phytochemicals: From Caenorhabditis elegans, Drosophila melanogaster, rodents to clinical studies

Anti-aging research has become critical since the elderly population is increasing dramatically in this era. With the establishment of frailty phenotype and frailty index, the importance of anti-frailty research is concurrently enlightened. The application of natural phytochemicals against aging or frailty is always intriguing, and abundant related studies have been published. Various models are designed for biological research, and each model has its strength and weakness in deciphering the complex aging mechanisms. In this article, we attempt to show the potential of Caenorhabditis elegans in the study of phytochemicals' effects on anti-aging by comparing it to other animal models. In this review, the lifespan extension and anti-aging effects are demonstrated by various physical, cellular, or molecular biomarkers of dietary phytochemicals, including resveratrol, curcumin, urolithin A, sesamin, fisetin, quercetin, epigallocatechin-3-gallate, epicatechin, spermidine, sulforaphane, along with extracts of broccoli, cocoa, and blueberry. Meanwhile, the frequency of phytochemicals and models studied or presented in publications since 2010 were analyzed, and the most commonly mentioned animal models were rats, mice, and the nematode C. elegans. This up-to-date summary of the anti-aging effect of certain phytochemicals has demonstrated powerful potential for anti-aging or anti-frailty in the human population.

Research progress on the mechanism of aging of vascular endothelial cells and the intervention of traditional Chinese medicine: A review

Vascular senescence is the basic factor of many cardiovascular diseases. Vascular endothelium, as a protective barrier between blood and vascular wall, plays an important role in maintaining the integrity and homeostasis of vascular system. Endothelial cell senescence is an important pathological change of vascular senescence. In recent years, more and more studies have been conducted on vascular endothelial cell senescence, especially on its mechanism. Many research results showed that the mechanism is various, but the systematic elucidation still lacks. Western medicine has little choice in the prevention and treatment of endothelial cell senescence, and the control effect is also limited, while Chinese medicine makes up for the deficiency in this regard. The main mechanisms of vascular endothelial cell aging and the related research progress of traditional Chinese medicine in the prevention and treatment of vascular endothelial aging in recent years were summarized in this paper to provide reference for the research of traditional Chinese medicine in anti-vascular aging and the prevention and treatment of cardiovascular disease.

Plasma Exosomal miR-199a-5p Derived from Preeclampsia with Severe Features Impairs Endothelial Cell Function via Targeting SIRT1

Preeclampsia (PE) is a pregnancy complication with high maternal and fetal morbidity and mortality rates. During pregnancy, the concentration of exosomes in the maternal blood circulation would increase, establishing that plasma exosomes play a role in the development of pregnancy. Our previous study implied the important role of exosomal miR-199a-5p in preeclampsia with severe features (sPE). This study aims to reveal the role of exosomal miR-199a-5p in contribution to the development of sPE. The results showed that the expression of miR-199a-5p was significantly higher in plasma exosomes and placenta tissue from patients with sPE than that in normal pregnant women. Additionally, hydrogen peroxide (H₂O₂) could upregulate the expression of miR-199a-5p in BeWo cells and cell-derived exosomes. In terms of the regulatory effect, exosomal miR-199a-5p was observed to inhibit the expression of SIRT1 in human umbilical venous endothelial cells (HUVECs). Moreover, the treatment of both miR-199a-5p-overexpressed exosomes and SIRT1 inhibitor EX527 could decrease the nitric oxide production, elevate the intracellular reactive oxygen species level, and enhance the expressions of ICAM-1 and VCAM-1 of HUVECs. Thus, our findings suggest that the upregulated plasma exosomal miR-199a-5p in sPE might result from the trophoblast of the impaired placenta under oxidative stress. Furthermore, exosomal miR-199a-5p could impair the endothelial cell function via targeting SIRT1, contributing to the development of preeclampsia.

Impact of Phytochemicals on PPAR Receptors: Implications for Disease Treatments

Peroxisome proliferator-activated receptors (PPARs) are members of the ligand-dependent nuclear receptor family. PPARs have attracted wide attention as pharmacologic mediators to manage multiple diseases and their underlying signaling targets. They mediate a broad range of specific biological activities and multiple organ toxicity, including cellular differentiation, metabolic syndrome, cancer, atherosclerosis, neurodegeneration, cardiovascular diseases, and inflammation related to their up/downstream signaling pathways. Consequently, several types of selective PPAR ligands, such as fibrates and thiazolidinediones (TZDs), have been approved as their pharmacological agonists. Despite these advances, the use of PPAR agonists is known to cause adverse effects in various systems. Conversely, some naturally occurring PPAR agonists, including polyunsaturated fatty acids and natural endogenous PPAR agonists curcumin and resveratrol, have been introduced as safe agonists as a result of their clinical evidence or preclinical experiments. This review focuses on research on plant-derived active ingredients (natural phytochemicals) as potential safe and promising PPAR agonists. Moreover, it provides a comprehensive review and critique of the role of phytochemicals in PPARs-related diseases and provides an understanding of phytochemical-mediated PPAR-dependent and -independent cascades. The findings of this research will help to define the functions of phytochemicals as potent PPAR pharmacological agonists in underlying disease mechanisms and their related complications.

3,4′,5-Trimethoxy-trans-stilbene Alleviates Endothelial Dysfunction in Diabetic and Obese Mice via Activation of the AMPK/SIRT1/eNOS Pathway

3,4′,5-trimethoxy-trans-stilbene (TMS) is a methoxylated derivative of resveratrol. Previous studies showed the vaso-protective effects of resveratrol; nevertheless, research on this derivative is scarce. The current study aimed to explore whether TMS can alleviate endothelial dysfunction in diabetic and obese mice, along with the underlying mechanisms. Thoracic aortas isolated from male C57BL/6J mice and primary cultures of rat aortic endothelial cells were treated with high glucose with or without TMS. High glucose exposure impaired acetylcholine-induced endothelium-dependent relaxations, down-regulated NO bioavailability and the AMP-activated protein kinase (AMPK)/Sirtuin 1 (SIRT1)/endothelial nitric oxide synthase (eNOS) pathway, increased endoplasmic reticulum (ER) stress and oxidative stress, which were reversed by TMS treatment. Moreover, the protective effects of TMS were abolished by Compound C (AMPK inhibitor), and EX527 (SIRT1 inhibitor). The mice were fed with high-fat diet (60% kcal% fat) for 14 weeks to establish a diabetic and obese model, and were orally administered TMS (10 mg/kg/day) in the last 4 weeks. Chronic TMS treatment alleviated endothelial dysfunction via enhancing the AMPK/SIRT1/eNOS pathway and attenuated oxidative stress and ER stress in aortas of diet-induced obese mice. In summary, our study reveals the potent vaso-protective effect of TMS and its therapeutic potential against endothelial dysfunction in metabolic disorders.

Resveratrol in Treating Diabetes and Its Cardiovascular Complications: A Review of Its Mechanisms of Action

Diabetes mellitus (DM) is one of the most prevalent chronic diseases worldwide. High morbidity and mortality caused by DM are closely linked to its complications in multiple organs/tissues, including cardiovascular complications, diabetic nephropathy, and diabetic neuropathy. Resveratrol is a plant-derived polyphenolic compound with pleiotropic protective effects, ranging from antioxidant and anti-inflammatory to hypoglycemic effects. Recent studies strongly suggest that the consumption of resveratrol offers protection against diabetes and its cardiovascular complications. The protective effects of resveratrol involve the regulation of multiple signaling pathways, including inhibition of oxidative stress and inflammation, enhancement of insulin sensitivity, induction of autophagy, regulation of lipid metabolism, promotion of GLUT4 expression, and translocation, and activation of SIRT1/AMPK signaling axis. The cardiovascular protective effects of resveratrol have been recently reviewed in the literature, but the role of resveratrol in preventing diabetes mellitus and its cardiovascular complications has not been systematically reviewed. Therefore, in this review, we summarize the pharmacological effects and mechanisms of action of resveratrol based on in vitro and in vivo studies, highlighting the therapeutic potential of resveratrol in the prevention and treatment of diabetes and its cardiovascular complications.

Targeting endothelial dysfunction and inflammation

Vascular endothelium maintains vascular homeostasis through liberating a spectrum of vasoactive molecules, both protective and harmful regulators of vascular tone, structural remodeling, inflammation and atherogenesis. An intricate balance between endothelium-derived relaxing factors (nitric oxide, prostacyclin and endothelium-derived hyperpolarizing factor) and endothelium-derived contracting factors (superoxide anion, endothelin-1 and constrictive prostaglandins) tightly regulates vascular function. Disruption of such balance signifies endothelial dysfunction, a critical contributor in aging and chronic cardiometabolic disorders, such as obesity, diabetes, hypertension, dyslipidemia and atherosclerotic vascular diseases. Among many proposed cellular and molecular mechanisms causing endothelial dysfunction, oxidative stress and inflammation are often the pivotal players and they are naturally considered as useful targets for intervention in patients with cardiovascular and metabolic diseases. In this article, we provide a recent update on the therapeutic values of pharmacological agents, such as cyclooxygenase-2 inhibitors, renin-angiotensin-system inhibitors, bone morphogenic protein 4 inhibitors, peroxisome proliferator-activated receptor δ agonists, and glucagon-like peptide 1-elevating drugs, and the physiological factors, particularly hemodynamic forces, that improve endothelial function by targeting endothelial oxidative stress and inflammation.

PPARβ down-regulation is involved in high glucose-induced endothelial injury via acceleration of nitrative stress

Endothelial injury plays a vital role in vascular lesions from diabetes mellitus (DM). Therapeutic targets against endothelial damage may provide critical venues for the treatment of diabetic vascular diseases. Peroxisome proliferator-activated receptor β (PPARβ) is a crucial regulator in DM and its complications. However, the molecular signal mediating the roles of PPARβ in DM-induced endothelial dysfunction is not fully understood. The impaired endothelium-dependent relaxation and destruction of the endothelium structures appeared in high glucose incubated rat aortic rings. A high glucose level significantly decreased the expression of PPARβ and endothelial nitric oxide synthase (eNOS) at the mRNA and protein levels, and reduced the concentration of nitric oxide (NO), which occurred in parallel with an increase in the expression of inducible nitric oxide synthase (iNOS) and 3-nitrotyrosine. The effect of high glucose was inhibited by GW0742, a PPARβ agonist. Both GSK0660 (PPARβ antagonist) and NG-nitro-l-arginine-methyl ester (NOS inhibitor) could reverse the protective effects of GW0742. These results suggest that the activation of nitrative stress may, at least in part, mediate the down-regulation of PPARβ in high glucose-impaired endothelial function in rat aorta. PPARβ-nitrative stress may hold potential in treating vascular complications from DM.

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.

SIRT1-FOXOs activity regulates diabetic complications

The prevalence of diabetes is continuously increasing in the recent decades. Persistent hyperglycemia, hyperinsulinemia and the subsequent oxidative stress result in diabetic complications, primarily categorized as microvascular (nephropathy, retinopathy and neuropathy) and macrovascular (cardiomyopathy) complications. The complications are prevalent in both type 1 and type 2 diabetic patients. Polyol pathway, elevated AGE production, PKC activation and hexosamine pathway are indeed the critical pathways involved in the progression of diabetic complications. Silent information regulator 2 or SIR2 or more commonly known as sirtuins are NAD⁺ dependent histone deacetylase. SIRT1, a member of the sirtuin family has been extensively studied for its role in lifespan extension and needs to be explored for its beneficial effects in diabetic complications. Moreover, it is also known to regulate the activity of other proteins and transcription factors. One such substrate of SIRT1 is FOXOs transcription factor which has gained much attention as the mediator of various cellular processes such as cell cycle arrest and proliferation, DNA repair and metabolism. It has been reported that SIRT1 regulates the activity of FOXOs, whereas few recent advances also suggest a role FOXOs in governing the activity of SIRT1, which permits for a crosstalk between SIRT1 and FOXOs. Therefore, the focus of the present review is to describe and explore the interaction between SIRT1 and FOXOs, predominantly FOXO1 and FOXO3 and to understand the underlying mechanism of SIRT1-FOXOs in controlling and alleviating diabetic complications. Thus, this crosstalk suggests that SIRT1 and FOXOs may serve as potential therapeutic targets in treating diabetic complications.

Influence of the Bioactive Diet Components on the Gene Expression Regulation

Diet bioactive components, in the concept of nutrigenetics and nutrigenomics, consist of food constituents, which can transfer information from the external environment and influence gene expression in the cell and thus the function of the whole organism. It is crucial to regard food not only as the source of energy and basic nutriments, crucial for living and organism development, but also as the factor influencing health/disease, biochemical mechanisms, and activation of biochemical pathways. Bioactive components of the diet regulate gene expression through changes in the chromatin structure (including DNA methylation and histone modification), non-coding RNA, activation of transcription factors by signalling cascades, or direct ligand binding to the nuclear receptors. Analysis of interactions between diet components and human genome structure and gene activity is a modern approach that will help to better understand these relations and will allow designing dietary guidances, which can help maintain good health.

Aging-Induced Impairment of Vascular Function: Mitochondrial Redox Contributions and Physiological/Clinical Implications

Significance: The vasculature responds to the respiratory needs of tissue by modulating luminal diameter through smooth muscle constriction or relaxation. Coronary perfusion, diastolic function, and coronary flow reserve are drastically reduced with aging. This loss of blood flow contributes to and exacerbates pathological processes such as angina pectoris, atherosclerosis, and coronary artery and microvascular disease. Recent Advances: Increased attention has recently been given to defining mechanisms behind aging-mediated loss of vascular function and development of therapeutic strategies to restore youthful vascular responsiveness. The ultimate goal aims at providing new avenues for symptom management, reversal of tissue damage, and preventing or delaying of aging-induced vascular damage and dysfunction in the first place. Critical Issues: Our major objective is to describe how aging-associated mitochondrial dysfunction contributes to endothelial and smooth muscle dysfunction via dysregulated reactive oxygen species production, the clinical impact of this phenomenon, and to discuss emerging therapeutic strategies. Pathological changes in regulation of mitochondrial oxidative and nitrosative balance (Section 1) and mitochondrial dynamics of fission/fusion (Section 2) have widespread effects on the mechanisms underlying the ability of the vasculature to relax, leading to hyperconstriction with aging. We will focus on flow-mediated dilation, endothelial hyperpolarizing factors (Sections 3 and 4), and adrenergic receptors (Section 5), as outlined in Figure 1. The clinical implications of these changes on major adverse cardiac events and mortality are described (Section 6). Future Directions: We discuss antioxidative therapeutic strategies currently in development to restore mitochondrial redox homeostasis and subsequently vascular function and evaluate their potential clinical impact (Section 7). Antioxid. Redox Signal. 35, 974-1015.

Relieving Cellular Energy Stress in Aging, Neurodegenerative, and Metabolic Diseases, SIRT1 as a Therapeutic and Promising Node

The intracellular energy state will alter under the influence of physiological or pathological stimuli. In response to this change, cells usually mobilize various molecules and their mechanisms to promote the stability of the intracellular energy status. Mitochondria are the main source of ATP. Previous studies have found that the function of mitochondria is impaired in aging, neurodegenerative diseases, and metabolic diseases, and the damaged mitochondria bring lower ATP production, which further worsens the progression of the disease. Silent information regulator-1 (SIRT1) is a multipotent molecule that participates in the regulation of important biological processes in cells, including cellular metabolism, cell senescence, and inflammation. In this review, we mainly discuss that promoting the expression and activity of SIRT1 contributes to alleviating the energy stress produced by physiological and pathological conditions. The review also discusses the mechanism of precise regulation of SIRT1 expression and activity in various dimensions. Finally, according to the characteristics of this mechanism in promoting the recovery of mitochondrial function, the relationship between current pharmacological preparations and aging, neurodegenerative diseases, metabolic diseases, and other diseases was analyzed.

Recent Advances in Health Benefits of Stilbenoids

Biological targeting or molecular targeting is the main strategy in drug development and disease prevention. However, the problem of "off-targets" cannot be neglected. Naturally derived drugs are preferred over synthetic compounds in pharmaceutical markets, and the main goals are high effectiveness, lower cost, and fewer side effects. Single-target drug binding may be the major cause of failure, as the pathogenesis of diseases is predominantly multifactorial. Naturally derived drugs are advantageous because they are expected to have multitarget effects, but not off-targets, in disease prevention or therapeutic actions. The capability of phytochemicals to modulate molecular signals in numerous diseases has been widely discussed. Among them, stilbenoids, especially resveratrol, have been well-studied, along with their potential molecular targets, including AMPK, Sirt1, NF-κB, PKC, Nrf2, and PPARs. The analogues of resveratrol, pterostilbene, and hydroxylated-pterostilbene may have similar, if not more, potential biological targeting effects compared with their original counterpart. Furthermore, new targets that have been discussed in recent studies are reviewed in this paper.

Two methoxy derivatives of resveratrol, 3,3',4,5'-tetramethoxy-trans-stilbene and 3,4',5-trimethoxy-trans-stilbene, suppress lipopolysaccharide-induced inflammation through inactivation of MAPK and NF-κB pathways in RAW 264.7 cells

Background

3,3′,4,5′-tetramethoxy-trans-stilbene (3,3′,4,5′-TMS) and 3,4′,5-trimethoxy-trans-stilbene (3,4′,5-TMS) are two methoxy derivatives of resveratrol. Previous researches have proved that resveratrol and its analogues have anti-inflammatory effect through suppressing mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways. This study aims to study whether 3,3′,4,5′-TMS and 3,4′,5-TMS alleviate inflammation and the underlying mechanism.

Methods

RAW 264.7 macrophage cells were treated with lipopolysaccharide (LPS) to induce inflammation and pretreated with 3,3′,4,5′-TMS or 3,4′,5-TMS. Cell viability was measured with the 3-(4,5)-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Nitric oxide (NO) release was detected by Griess reagent. The secretions of pro-inflammatory cytokines were assessed by ELISA kits. Protein expressions of signaling molecules were determined by Western blotting. Reactive oxygen species (ROS) production was detected by fluorescence staining and malondialdehyde (MDA) assay.

Results

3,3′,4,5′-TMS and 3,4′,5-TMS suppressed LPS-induced NO release and pro-inflammatory cytokines (IL-6 and TNF-α) secretions in a dose-dependent manner in RAW 264.7 cells. 3,3′,4,5′-TMS and 3,4′,5-TMS significantly down-regulated the LPS-induced expressions of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), and partially suppressed the activation of MAPK (phosphorylation of p38, JNK, ERK), and NF-κB (phosphorylation of IKKα/β, p65 and IκBα) signaling pathways; where phosphorylation of ERK and p65 was mildly but not significantly decreased by 3,3′,4,5′-TMS. LPS-induced NF-κB/p65 nuclear translocation was inhibited by both 3,3′,4,5′-TMS and 3,4′,5-TMS. Moreover, both resveratrol derivatives decreased the ROS levels.

Conclusions

3,3′,4,5′-TMS and 3,4′,5-TMS significantly suppress LPS-induced inflammation in RAW 264.7 cells through inhibition of MAPK and NF-κB signaling pathways and also provide anti-oxidative effect. This study reveals potential therapeutic applications of 3,3′,4,5′-TMS and 3,4′,5-TMS for inflammatory diseases.

Roles and Therapeutic Implications of Endoplasmic Reticulum Stress and Oxidative Stress in Cardiovascular Diseases

In different pathological states that cause endoplasmic reticulum (ER) calcium depletion, altered glycosylation, nutrient deprivation, oxidative stress, DNA damage or energy perturbation/fluctuations, the protein folding process is disrupted and the ER becomes stressed. Studies in the past decade have demonstrated that ER stress is closely associated with pathogenesis of obesity, insulin resistance and type 2 diabetes. Excess nutrients and inflammatory cytokines associated with metabolic diseases can trigger or worsen ER stress. ER stress plays a critical role in the induction of endothelial dysfunction and atherosclerosis. Signaling pathways including AMP-activated protein kinase and peroxisome proliferator-activated receptor have been identified to regulate ER stress, whilst ER stress contributes to the imbalanced production between nitric oxide (NO) and reactive oxygen species (ROS) causing oxidative stress. Several drugs or herbs have been proved to protect against cardiovascular diseases (CVD) through inhibition of ER stress and oxidative stress. The present article reviews the involvement of ER stress and oxidative stress in cardiovascular dysfunction and the potential therapeutic implications.

Non-shivering Thermogenesis Signalling Regulation and Potential Therapeutic Applications of Brown Adipose Tissue

In mammals, thermogenic organs exist in the body that increase heat production and enhance energy regulation. Because brown adipose tissue (BAT) consumes energy and generates heat, increasing energy expenditure via BAT might be a potential strategy for new treatments for obesity and obesity-related diseases. Thermogenic differentiation affects normal adipose tissue generation, emphasizing the critical role that common transcriptional regulation factors might play in common characteristics and sources. An understanding of thermogenic differentiation and related factors could help in developing ways to improve obesity indirectly or directly through targeting of specific signalling pathways. Many studies have shown that the active components of various natural products promote thermogenesis through various signalling pathways. This article reviews recent major advances in this field, including those in the cyclic adenosine monophosphate-protein kinase A (cAMP-PKA), cyclic guanosine monophosphate-GMP-dependent protein kinase G (cGMP-AKT), AMP-activated protein kinase (AMPK), mammalian target of rapamycin (mTOR), transforming growth factor-β/bone morphogenic protein (TGF-β/BMP), transient receptor potential (TRP), Wnt, nuclear factor-κ-light-chain-enhancer of activated B cells (NF-κΒ), Notch and Hedgehog (Hh) signalling pathways in brown and brown-like adipose tissue. To provide effective information for future research on weight-loss nutraceuticals or drugs, this review also highlights the natural products and their active ingredients that have been reported in recent years to affect thermogenesis and thus contribute to weight loss via the above signalling pathways.

PPARdelta in Affected Atopic Dermatitis and Psoriasis: A Possible Role in Metabolic Reprograming

Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors expressed in the skin. Three PPAR isotypes, α (NRC1C1), β or δ (NRC1C2) and γ (NRC1C3), have been identified. After activation through ligand binding, PPARs heterodimerize with the 9-cis-retinoic acid receptor (RXR), another nuclear hormone receptor, to bind to specific PPAR-responsive elements in regulatory regions of target genes mainly involved in organogenesis, cell proliferation, cell differentiation, inflammation and metabolism of lipids or carbohydrates. Endogenous PPAR ligands are fatty acids and fatty acid metabolites. In past years, much emphasis has been given to PPARα and γ in skin diseases. PPARβ/δ is the least studied PPAR family member in the skin despite its key role in several important pathways regulating inflammation, keratinocyte proliferation and differentiation, metabolism and the oxidative stress response. This review focuses on the role of PPARβ/δ in keratinocytes and its involvement in psoriasis and atopic dermatitis. Moreover, the relevance of targeting PPARβ/δ to alleviate skin inflammation is discussed.

Resveratrol Ameliorates High-Fat-Diet-Induced Abnormalities in Hepatic Glucose Metabolism in Mice via the AMP-Activated Protein Kinase Pathway

Diabetes mellitus is highly prevalent worldwide. High-fat-diet (HFD) consumption can lead to liver fat accumulation, impair hepatic glycometabolism, and cause insulin resistance and the development of diabetes. Resveratrol has been shown to improve the blood glucose concentration of diabetic mice, but its effect on the abnormal hepatic glycometabolism induced by HFD-feeding and the mechanism involved are unknown. In this study, we determined the effects of resveratrol on the insulin resistance of high-fat-diet-fed mice and a hepatocyte model by measuring serum biochemical indexes, key indicators of glycometabolism, glucose uptake, and glycogen synthesis in hepatocytes. We found that resveratrol treatment significantly ameliorated the HFD-induced abnormalities in glucose metabolism in mice, increased glucose absorption and glycogen synthesis, downregulated protein phosphatase 2A (PP2A) and activated Ca²⁺/CaM-dependent protein kinase kinase β (CaMKKβ), and increased the phosphorylation of AMP-activated protein kinase (AMPK). In insulin-resistant HepG2 cells, the administration of a PP2A activator or CaMKKβ inhibitor attenuated the effects of resveratrol, but the administration of an AMPK inhibitor abolished the effects of resveratrol. Resveratrol significantly ameliorates abnormalities in glycometabolism induced by HFD-feeding and increases glucose uptake and glycogen synthesis in hepatocytes. These effects are mediated through the activation of AMPK by PP2A and CaMKKβ.

Exogenous Hydrogen Sulfide Plays an Important Role by Regulating Autophagy in Diabetic-Related Diseases

Autophagy is a vital cell mechanism which plays an important role in many physiological processes including clearing long-lived, accumulated and misfolded proteins, removing damaged organelles and regulating growth and aging. Autophagy also participates in a variety of biological functions, such as development, cell differentiation, resistance to pathogens and nutritional hunger. Recently, autophagy has been reported to be involved in diabetes, but the mechanism is not fully understood. Hydrogen sulfide (H₂S) is a colorless, water-soluble, flammable gas with the typical odor of rotten eggs, which has been known as a highly toxic gas for many years. However, it has been reported recently that H₂S, together with nitric oxide and carbon monoxide, is an important gas signal transduction molecule. H₂S has been reported to play a protective role in many diabetes-related diseases, but the mechanism is not fully clear. Recent studies indicate that H₂S plays an important role by regulating autophagy in many diseases including cancer, tissue fibrosis diseases and glycometabolic diseases; however, the related mechanism has not been fully studied. In this review, we summarize recent research on the role of H₂S in regulating autophagy in diabetic-related diseases to provide references for future related research.

Epigenetic Modulating Chemicals Significantly Affect the Virulence and Genetic Characteristics of the Bacterial Plant Pathogen Xanthomonas campestris pv. campestris

Epigenetics is the study of heritable alterations in phenotypes that are not caused by changes in DNA sequence. In the present study, we characterized the genetic and phenotypic alterations of the bacterial plant pathogen Xanthomonas campestris pv. campestris (Xcc) under different treatments with several epigenetic modulating chemicals. The use of DNA demethylating chemicals unambiguously caused a durable decrease in Xcc bacterial virulence, even after its reisolation from infected plants. The first-time use of chemicals to modify the activity of sirtuins also showed some noticeable results in terms of increasing bacterial virulence, but this effect was not typically stable. Changes in treated strains were also confirmed by using methylation sensitive amplification (MSAP), but with respect to registered SNPs induction, it was necessary to consider their contribution to the observed polymorphism. The molecular basis of the altered virulence was deciphered by using dualRNA-seq analysis of treated Xcc strains infecting Brassica rapa plants. The results of the present study should promote more intensive research in the generally understudied field of bacterial epigenetics, where artificially induced modification by epigenetic modulating chemicals can significantly increase the diversity of bacterial properties and potentially contribute to the further development of the fields, such as bacterial ecology and adaptation.

Epigenetic Remodeling in Obesity-Related Vascular Disease

Significance: The prevalence of obesity and cardiometabolic phenotypes is alarmingly increasing across the globe and is associated with atherosclerotic vascular complications and high mortality. In spite of multifactorial interventions, vascular residual risk remains high in this patient population, suggesting the need for breakthrough therapies. The mechanisms underpinning obesity-related vascular disease remain elusive and represent an intense area of investigation. Recent Advances: Epigenetic modifications-defined as environmentally induced chemical changes of DNA and histones that do not affect DNA sequence-are emerging as a potent modulator of gene transcription in the vasculature and might significantly contribute to the development of obesity-induced endothelial dysfunction. DNA methylation and histone post-translational modifications cooperate to build complex epigenetic signals, altering transcriptional networks that are implicated in redox homeostasis, mitochondrial function, vascular inflammation, and perivascular fat homeostasis in patients with cardiometabolic disturbances. Critical Issues: Deciphering the epigenetic landscape in the vasculature is extremely challenging due to the complexity of epigenetic signals and their function in regulating transcription. An overview of the most important epigenetic pathways is required to identify potential molecular targets to treat or prevent obesity-related endothelial dysfunction and atherosclerotic disease. This would enable the employment of precision medicine approaches in this setting. Future Directions: Current and future research efforts in this field entail a better definition of the vascular epigenome in obese patients as well as the unveiling of novel, cell-specific chromatin-modifying drugs that are able to erase specific epigenetic signals that are responsible for maladaptive transcriptional alterations and vascular dysfunction in obese patients. Antioxid. Redox Signal. 34, 1165-1199.

Cell-specific epigenetic changes in atherosclerosis

Atherosclerosis is a disease of large and medium arteries that can lead to life-threatening cerebrovascular and cardiovascular consequences such as heart failure and stroke and is a major contributor to cardiovascular-related mortality worldwide. Atherosclerosis development is a complex process that involves specific structural, functional and transcriptional changes in different vascular cell populations at different stages of the disease. The application of single-cell RNA sequencing (scRNA-seq) analysis has discovered not only disease-related cell-specific transcriptomic profiles but also novel subpopulations of cells once thought as homogenous cell populations. Vascular cells undergo specific transcriptional changes during the entire course of the disease. Epigenetics is the instruction-set-architecture in living cells that defines and maintains the cellular identity by regulating the cellular transcriptome. Although different cells contain the same genetic material, they have different epigenomic signatures. The epigenome is plastic, dynamic and highly responsive to environmental stimuli. Modifications to the epigenome are driven by an array of epigenetic enzymes generally referred to as writers, erasers and readers that define cellular fate and destiny. The reversibility of these modifications raises hope for finding novel therapeutic targets for modifiable pathological conditions including atherosclerosis where the involvement of epigenetics is increasingly appreciated. This article provides a critical review of the up-to-date research in the field of epigenetics mainly focusing on in vivo settings in the context of the cellular role of individual vascular cell types in the development of atherosclerosis.

Vascular Effects of the Polyphenolic Nutraceutical Supplement Taurisolo®: Focus on the Protection of the Endothelial Function

Preservation of vascular endothelium integrity and functionality represents an unmet medical need. Indeed, endothelial dysfunction leads to decreased nitric oxide biosynthesis, which is prodromic of hypertension and hypercoagulability. In this panorama, the nutraceutical supplement Taurisolo^®, a polyphenolic extract from Aglianico cultivar grape, rich in catechin and procyanidins, was evaluated as a vasoprotective, vasorelaxing, anti-hypertensive and anti-coagulant agent in: cell lines, isolated vessels, in vivo models of chronic hypertension and hypercoagulability, and in clinical tests of endothelial reactivity. Taurisolo^® demonstrated to fully protect vascular cell viability from oxidative stimulus at 100 µg/mL and evoke vasorelaxing effects (Emax = 80.6% ± 1.9 and pEC50 = 1.19 ± 0.03) by activation of the Sirtuins-AMPK-pathway. Moreover, Taurisolo^®, chronically administered at 20 mg/Kg/die in in vivo experiments, inhibited the onset of cardiac hypertrophy (heart weight/rat weight = 3.96 ± 0.09 vs. 4.30 ± 0.03), hypercoagulability (decrease of fibrinogen vs. control: p < 0.01) and hypertension (mean of Psys: 200 ± 2 vs. control 234 ± 2 mmHg) and improved endothelial function (Emax = 88.9% ± 1.5 vs. control 59.6% ± 3.6; flow-mediated dilation in healthy volunteers after 400 mg twice daily for 8 weeks vs. baseline: p = 0.019). In conclusion, Taurisolo^® preserves the vascular function against ox-inflamm-ageing process and the consequent cardiovascular accidents.

Silymarin ameliorates the disordered glucose metabolism of mice with diet-induced obesity by activating the hepatic SIRT1 pathway

Obesity-induced insulin resistance is the principal cause of type 2 diabetes worldwide. The use of natural products for the treatment of diabetes is increasingly attracting attention. Silymarin (SLM) is a flavonolignan compound that has been shown to have promise for the treatment of diabetes. In the present study, we aimed to investigate the mechanisms underlying its therapeutic effects. C57BL/6 mice were fed a high-fat diet (HFD) for 12 weeks and then orally administered SLM (30 mg/kg) daily for 1 month. The effects of SLM were also investigated in HepG2 cells that had been rendered insulin resistant by palmitic acid (PA) treatment. SLM ameliorated the dyslipidemia, hepatic steatosis, and insulin resistance of the HFD-fed mice. HFD-feeding and PA treatment reduced the expression of sirtuin-1 (SIRT1) in the livers of the mice and in HepG2 cells, respectively. SLM increased the phosphorylation of AKT and FOXO1, and reduced the level of FOXO1 acetylation in PA-treated cells. However, SIRT1 knockdown by RNA interference reduced these effects of SLM. Moreover, the results of molecular dynamic simulation and in vitro activity assays indicated that SLM may directly bind to SIRT1 and increase its enzymatic activity. These findings suggest that hepatic SIRT1 may be an important pharmacological target of SLM and mediate effects on insulin resistance and gluconeogenesis, which may underlie its anti-diabetic activity.

High phosphate impairs arterial endothelial function through AMPK-related pathways in mouse resistance arteries

AIMS

In patients with renal disease, high serum phosphate shows a relationship with cardiovascular risk. We speculate that high phosphate (HP) impairs arterial vasodilation via the endothelium and explore potential underlying mechanisms.

METHODS

Isolated vessel relaxation, endothelial function, glomerular filtration rate (GFR), oxidative stress status and protein expression were assessed in HP diet mice. Mitochondrial function and protein expression were assessed in HP-treated human umbilical vein endothelial cells (HUVECs).

RESULTS

High phosphate (1.3%) diet for 12 weeks impaired endothelium-dependent relaxation in mesenteric arteries, kidney interlobar arteries and afferent arterioles; reduced GFR and the blood pressure responses to acute administration of acetylcholine. The PPARα/LKB1/AMPK/eNOS pathway was attenuated in the endothelium of mesenteric arteries from HP diet mice. The observed vasodilatory impairment of mesenteric arteries was ameliorated by PPARα agonist WY-14643. The phosphate transporter PiT-1 knockdown prevented HP-mediated suppression of eNOS activity by impeding phosphorus influx in HUVECs. Endothelium cytoplasmic and mitochondrial reactive oxygen species (ROS) were increased in HP diet mice. Moreover HP decreased the expression of mitochondrial-related antioxidant genes. Finally, mitochondrial membrane potential and PGC-1α expression were reduced by HP treatment in HUVECs, which was partly restored by AMPKα agonist.

CONCLUSIONS

HP impairs endothelial function by reducing NO bioavailability via decreasing eNOS activity and increasing mitochondrial ROS, in which the AMPK-related signalling pathways may play a key role.

Sirtuin 1 ameliorates defenestration in hepatic sinusoidal endothelial cells during liver fibrosis via inhibiting stress-induced premature senescence

OBJECTIVE

Premature senescence is related to progerin and involves in endothelial dysfunction and liver diseases. Activating sirtuin 1 (SIRT1) ameliorates liver fibrosis. However, the mechanisms of premature senescence in defenestration of hepatic sinusoidal endothelial cells (HSECs) and how SIRT1 affects HSECs fenestrae remain elusive.

METHODS

We employed the CCl4 -induced liver fibrogenesis rat models and cultured primary HSECs in vitro, administered with the SIRT1-adenovirus vector, the activator of SIRT1 and knockdown NOX2. We measured the activity of senescence-associated β-galactosidase (SA-β-gal) in HSECs. Meanwhile, the protein expression of SIRT1, NOX2, progerin, Lamin A/C, Ac p53 K381 and total p53 was detected by Western blot, co-immunoprecipitation and immunofluorescence.

RESULTS

In vivo, premature senescence was triggered by oxidative stress during CCl4 -induced HSECs defenestration and liver fibrogenesis, whereas overexpressing SIRT1 with adenovirus vector lessened premature senescence to relieve CCl4 -induced HSECs defenestration and liver fibrosis. In vitro, HSECs fenestrae disappeared, with emerging progerin-associated premature senescence; these effects were aggravated by H2 O2 . Nevertheless, knockdown of NOX2, activation of SIRT1 with resveratrol and SIRT1-adenovirus vector inhibited progerin-associated premature senescence to maintain fenestrae through deacetylating p53. Furthermore, more Ac p53 K381 and progerin co-localized with the abnormal accumulation of actin filament (F-actin) in the nuclear envelope of H2 O2 -treated HSECs; in contrast, these effects were rescued by overexpressing SIRT1.

CONCLUSION

SIRT1-mediated deacetylation maintains HSECs fenestrae and attenuates liver fibrogenesis through inhibiting oxidative stress-induced premature senescence.

FKBPL and SIRT-1 Are Downregulated by Diabetes in Pregnancy Impacting on Angiogenesis and Endothelial Function

Diabetes in pregnancy is associated with adverse pregnancy outcomes including preterm birth. Although the mechanisms leading to these pregnancy complications are still poorly understood, aberrant angiogenesis and endothelial dysfunction play a key role. FKBPL and SIRT-1 are critical regulators of angiogenesis, however, their roles in pregnancies affected by diabetes have not been examined before in detail. Hence, this study aimed to investigate the role of FKBPL and SIRT-1 in pre-gestational (type 1 diabetes mellitus, T1D) and gestational diabetes mellitus (GDM). Placental protein expression of important angiogenesis proteins, FKBPL, SIRT-1, PlGF and VEGF-R1, was determined from pregnant women with GDM or T1D, and in the first trimester trophoblast cells exposed to high glucose (25 mM) and varying oxygen concentrations [21%, 6.5%, 2.5% (ACH-3Ps)]. Endothelial cell function was assessed in high glucose conditions (30 mM) and following FKBPL overexpression. Placental FKBPL protein expression was downregulated in T1D (FKBPL; p<0.05) whereas PlGF/VEGF-R1 were upregulated (p<0.05); correlations adjusted for gestational age were also significant. In the presence of GDM, only SIRT-1 was significantly downregulated (p<0.05) even when adjusted for gestational age (r=-0.92, p=0.001). Both FKBPL and SIRT-1 protein expression was reduced in ACH-3P cells in high glucose conditions associated with 6.5%/2.5% oxygen concentrations compared to experimental normoxia (21%; p<0.05). FKBPL overexpression in endothelial cells (HUVECs) exacerbated reduction in tubule formation compared to empty vector control, in high glucose conditions (junctions; p<0.01, branches; p<0.05). In conclusion, FKBPL and/or SIRT-1 downregulation in response to diabetic pregnancies may have a key role in the development of vascular dysfunction and associated complications affected by impaired placental angiogenesis.

Resveratrol: Mechanistic and therapeutic perspectives in pulmonary arterial hypertension

Resveratrol, trans 3,5,4'-trihydroxystilbene, is a stilbenoid polyphenol with a wide range of properties including antioxidant, neuroprotective, cardioprotective, anti-inflammatory and anticancer activities. It is found in the skins of grape (50-100 μg/mL), red wine, peanuts, bilberries, blueberries and cranberries. The most important effects of resveratrol have been found in cardiovascular disease, with pulmonary arterial hypertension (PAH) being a major severe and progressive component. Many factors are involved in the pathogenesis of PAH, including enzymes, transcription factors, proteins, chemokines, cytokines, hypoxia, oxidative stress and others. Resveratrol treats PAH through its actions on various signaling pathways. These signaling pathways are mainly suppressed SphK1-mediated NF-κB activation, BMP/SMAD signaling pathway, miR-638 and NR4A3/cyclin D1 pathway, SIRT1 pathway, Nrf-2, HIF-1 α expression, MAPK/ERK1 and PI3K/AKT pathways, and RhoA-ROCK signaling pathway. Resveratrol efficiently inhibits the proliferation of pulmonary arterial smooth muscle cells and right ventricular remodeling, which are underlying processes leading to enhanced PAH. While supportive evidence from randomized controlled trials is yet to be available, current in vitro and in vivo studies seem to be convincing and suggest a therapeutic promise for the use of resveratrol in PAH.

MicroRNA Modulation by Dietary Supplements in Obesity

The prevalence of obesity has dramatically increased over the last decades. Weight loss obtained through diet and exercise leads to a significant decrease in morbidity and mortality. Recently, there has been growing interest in the possible beneficial effects of dietary supplements (DSs), including polyphenols, fatty acids, and other plant-derived substances, as adjuvants in the management of obesity and metabolic diseases. Specifically, polyphenols, widely spread in vegetables and fruits, significantly modulate adipose tissue activities, contrasting inflammation and improving insulin sensitivity in preclinical and clinical studies. Remarkably, polyphenols are involved in complex microRNA networks, which play crucial roles in metabolic processes. The administration of different polyphenols and other plant-derived compounds led to significant changes in the microRNA expression profile in peripheral tissues in a growing number of preclinical studies. In particular, these compounds were able to revert obesity-induced microRNA dysregulation, leading to the inhibition of adipogenesis and the induction of weight loss. Furthermore, through microRNA modulation, they attenuated key metabolic alterations, including insulin resistance and lipid anomalies, in animal models of obesity. Some of them were also able to reduce proinflammatory cytokines in adipose tissue. The aim of this review is to summarize current evidence about the effect of plant-derived DSs on microRNA expression in obesity.

Histone Deacetylase SIRT1, Smooth Muscle Cell Function, and Vascular Diseases

Vascular smooth muscle cells (VSMCs), located in the media of artery, play key roles in maintaining the normal vascular physiological functions. Abnormality in VSMCs is implicated in vascular diseases (VDs), including atherosclerosis, abdominal aortic aneurysm (AAA), aortic dissection, and hypertension by regulating the process of inflammation, phenotypic switching, and extracellular matrix degradation. Sirtuins (SIRTs), a family of proteins containing seven members (from SIRT1 to SIRT7) in mammals, function as NAD⁺-dependent histone deacetylases and ADP-ribosyltransferases. In recent decades, great attention has been paid to the cardiovascular protective effects of SIRTs, especially SIRT1, suggesting a new therapeutic target for the treatment of VDs. In this review, we introduce the basic functions of SIRT1 against VSMC senescence, and summarize the contribution of SIRT1 derived from VSMCs in VDs. Finally, the potential new strategies based on SIRT1 activation have also been discussed with an emphasis on SIRT1 activators and calorie restriction to improve the prognosis of VDs.

Sirt1-PPARS Cross-Talk in Complex Metabolic Diseases and Inherited Disorders of the One Carbon Metabolism

Sirtuin1 (Sirt1) has a NAD (+) binding domain and modulates the acetylation status of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α) and Fork Head Box O1 transcription factor (Foxo1) according to the nutritional status. Sirt1 is decreased in obese patients and increased in weight loss. Its decreased expression explains part of the pathomechanisms of the metabolic syndrome, diabetes mellitus type 2 (DT2), cardiovascular diseases and nonalcoholic liver disease. Sirt1 plays an important role in the differentiation of adipocytes and in insulin signaling regulated by Foxo1 and phosphatidylinositol 3′-kinase (PI3K) signaling. Its overexpression attenuates inflammation and macrophage infiltration induced by a high fat diet. Its decreased expression plays a prominent role in the heart, liver and brain of rat as manifestations of fetal programming produced by deficit in vitamin B12 and folate during pregnancy and lactation through imbalanced methylation/acetylation of PGC1α and altered expression and methylation of nuclear receptors. The decreased expression of Sirt1 produced by impaired cellular availability of vitamin B12 results from endoplasmic reticulum stress through subcellular mislocalization of ELAVL1/HuR protein that shuttles Sirt1 mRNA between the nucleus and cytoplasm. Preclinical and clinical studies of Sirt1 agonists have produced contrasted results in the treatment of the metabolic syndrome. A preclinical study has produced promising results in the treatment of inherited disorders of vitamin B12 metabolism.

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.