Dietary spermidine for lowering high blood pressure

3,4-dimethoxychalcone induces autophagy and reduces neointimal hyperplasia and aortic lesions in mouse models of atherosclerosis

Autophagy inducers can prevent cardiovascular aging and age-associated diseases including atherosclerosis. Therefore, we hypothesized that autophagy-inducing compounds that act on atherosclerosis-relevant cells might have a protective role in the development of atherosclerosis. Here we identified 3,4-dimethoxychalcone (3,4-DC) as an inducer of autophagy in several cell lines from endothelial, myocardial and myeloid/macrophagic origin, as demonstrated by the aggregation of the autophagosome marker GFP-LC3 in the cytoplasm of cells, as well as the downregulation of its nuclear pool indicative of autophagic flux. In this respect, 3,4-DC showed a broader autophagy-inducing activity than another chalcone (4,4- dimethoxychalcone), spermidine and triethylene tetramine. Thus, we characterized the potential antiatherogenic activity of 3,4-DC in two different mouse models, namely, (i) neointima formation with smooth muscle expansion of vein segments grafted to the carotid artery and (ii) genetically predisposed ApoE-/- mice fed an atherogenic diet. In the vein graft model, local application of 3,4-DC was able to maintain the lumen of vessels and to reduce neointima lesions. In the diet-induced model, intraperitoneal injections of 3,4-DC significantly reduced the number of atherosclerotic lesions in the aorta. In conclusion, 3,4-DC stands out as an autophagy inducer with potent antiatherogenic activity.

Antihypertensive activity of different components of Veratrum alkaloids through metabonomic data analysis

BACKGROUND

Hypertension is a serious global public health issue. Blood pressure (BP) is still not effectively controlled in about 20 - 30% of hypertensive patients. Therefore, it is imperative to develop new treatments for hypertension. Veratrum alkaloids were once used for the clinical treatment of hypertension, the mechanism of which is still unclear. It was gradually phased out due to adverse reactions.

PURPOSE

This study aimed to investigate the short-term and long-term hypotensive profiles of different components of Veratrum alkaloids in spontaneously hypertensive rats (SHRs) to unveil their mechanisms of action.

RESULTS

Total Veratrum alkaloid (V), component A (A), and veratramine (M) quickly decreased BP within 30 min of treatment, reduced renal and cardiovascular damage, and improved relevant biochemical indicators (nitric oxide [NO], endothelin-1 [ET-1], angiotensin II [Ang II)], noradrenaline [NE], etc) in SHRs to delay stroke occurrence. Thereinto, A exhibited excellent protective effects in cardiovascular disease. The metabolomic profiles of SHRs treated with V, A, and M were significantly different from those of SHRs treated with vehicle. Thirteen metabolites were identified as potential pharmacodynamic biomarkers. Through Kyoto Encyclopedia of Genes and Genomes analysis, V, A, and M-induced hypotension was mainly related to alterations in nicotinate and nicotinamide metabolism, GABAergic synapses, linoleic acid metabolism, ketone body synthesis and degradation, arginine and proline metabolism, and urea cycle, of which nicotinate and nicotinamide metabolism was the key metabolic pathway to relieve hypertension.

CONCLUSION

This work shows that A is an effective and promising antihypertensive agent for hypertension treatment to reduce BP and hypertensive target organ damage, which is mainly mediated through modulating nicotinate and nicotinamide metabolism, RAS, and NO-ET homeostasis.

Spermidine Ameliorates Colitis via Induction of Anti-Inflammatory Macrophages and Prevention of Intestinal Dysbiosis

BACKGROUND AND AIMS

Exacerbated immune activation, intestinal dysbiosis and a disrupted intestinal barrier are common features among inflammatory bowel disease [IBD] patients. The polyamine spermidine, which is naturally present in all living organisms, is an integral component of the human diet, and exerts beneficial effects in human diseases. Here, we investigated whether spermidine treatment ameliorates intestinal inflammation and offers therapeutic potential for IBD treatment.

METHODS

We assessed the effect of oral spermidine administration on colitis severity in the T cell transfer colitis model in Rag2-/- mice by endoscopy, histology and analysis of markers of molecular inflammation. The effects on the intestinal microbiome were determined by 16S rDNA sequencing of mouse faeces. The impact on intestinal barrier integrity was evaluated in co-cultures of patient-derived macrophages with intestinal epithelial cells.

RESULTS

Spermidine administration protected mice from intestinal inflammation in a dose-dependent manner. While T helper cell subsets remained unaffected, spermidine promoted anti-inflammatory macrophages and prevented the microbiome shift from Firmicutes and Bacteroides to Proteobacteria, maintaining a healthy gut microbiome. Consistent with spermidine as a potent activator of the anti-inflammatory molecule protein tyrosine phosphatase non-receptor type 2 [PTPN2], its colitis-protective effect was dependent on PTPN2 in intestinal epithelial cells and in myeloid cells. The loss of PTPN2 in epithelial and myeloid cells, but not in T cells, abrogated the barrier-protective, anti-inflammatory effect of spermidine and prevented the anti-inflammatory polarization of macrophages.

CONCLUSION

Spermidine reduces intestinal inflammation by promoting anti-inflammatory macrophages, maintaining a healthy microbiome and preserving epithelial barrier integrity in a PTPN2-dependent manner.

VEGFC ameliorates salt-sensitive hypertension and hypertensive nephropathy by inhibiting NLRP3 inflammasome via activating VEGFR3-AMPK dependent autophagy pathway

Salt-sensitivity hypertension (SSHTN) is an independent predictor for cardiovascular mortality. VEGFC has been reported to be a protective role in SSHTN and hypertensive kidney injury. However, the underlying mechanisms remain largely unclear. The current study aimed to explore the protective effects and mechanisms of VEGFC against SSHTN and hypertensive nephropathy. Here, we reported that VEGFC attenuated high blood pressure as well as protected against renal inflammation and fibrosis in SSHTN mice. Moreover, VEGFC suppressed the activation of renal NLRP3 inflammasome in SSHTN mice. In vitro, we found VEGFC inhibited NLRP3 inflammasome activation, meanwhile, upregulated autophagy in high-salt-induced macrophages, while these effects were reversed by an autophagy inhibitor 3MA. Furthermore, in vivo, 3MA pretreatment weakened the protective effects of VEGFC on SSHTN and hypertensive nephropathy. Mechanistically, VEGF receptor 3 (VEGFR3) kinase domain activated AMPK by promoting the phosphorylation at Thr183 via binding to AMPK, thus enhancing autophagy activity in the context of high-salt-induced macrophages. These findings indicated that VEGFC inhibited NLRP3 inflammasome activation by promoting VEGFR3-AMPK-dependent autophagy pathway in high-salt-induced macrophages, which provided a mechanistic basis for the therapeutic target in SSHTN and hypertensive kidney injury.

Overcoming cohort heterogeneity for the prediction of subclinical cardiovascular disease risk

Cardiovascular disease remains a leading cause of mortality with an estimated half a billion people affected in 2019. However, detecting signals between specific pathophysiology and coronary plaque phenotypes using complex multi-omic discovery datasets remains challenging due to the diversity of individuals and their risk factors. Given the complex cohort heterogeneity present in those with coronary artery disease (CAD), we illustrate several different methods, both knowledge-guided and data-driven approaches, for identifying subcohorts of individuals with subclinical CAD and distinct metabolomic signatures. We then demonstrate that utilizing these subcohorts can improve the prediction of subclinical CAD and can facilitate the discovery of novel biomarkers of subclinical disease. Analyses acknowledging cohort heterogeneity through identifying and utilizing these subcohorts may be able to advance our understanding of CVD and provide more effective preventative treatments to reduce the burden of this disease in individuals and in society as a whole.

Identification of Biomarkers Related to Metabolically Unhealthy Obesity in Korean Obese Adolescents: A Cross-Sectional Study

BACKGROUND

The current study aimed to screen for relationships and different potential metabolic biomarkers involved between metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) in adolescents.

METHODS

The study included 148 obese adolescents aged between 14 and 16. The study participants were divided into MUO and MHO groups based on the age-specific adolescent metabolic syndrome (MetS) criteria of the International Diabetes Federation. The current study was conducted to investigate the clinical and metabolic differences between the MHO and MUO groups. Multivariate analyses were conducted to investigate the metabolites as independent predictors for the odds ratio and the presence of the MetS.

RESULTS

There were significant differences in the three acylcarnitines, five amino acids, glutamine/glutamate ratio, three biogenic amines, two glycerophospholipids, and the triglyceride-glucose index between the MUO group and those in the MHO group. Moreover, several metabolites were associated with the prevalence of MUO. Additionally, several metabolites were inversely correlated with MHO in the MUO group.

CONCLUSIONS

In this study, the biomarkers found in this study have the potential to reflect the clinical outcomes of the MUO group. These biomarkers will lead to a better understanding of MetS in obese adolescents.

Epithelial talin-1 protects mice from citrobacter rodentium-induced colitis by restricting bacterial crypt intrusion and enhancing t cell immunity

Pathogenic enteric Escherichia coli present a significant burden to global health. Food-borne enteropathogenic E. coli (EPEC) and Shiga toxin-producing E. coli (STEC) utilize attaching and effacing (A/E) lesions and actin-dense pedestal formation to colonize the gastrointestinal tract. Talin-1 is a large structural protein that links the actin cytoskeleton to the extracellular matrix though direct influence on integrins. Here we show that mice lacking talin-1 in intestinal epithelial cells (Tln1Δepi) have heightened susceptibility to colonic disease caused by the A/E murine pathogen Citrobacter rodentium. Tln1Δepi mice exhibit decreased survival, and increased colonization, colon weight, and histologic colitis compared to littermate Tln1fl/fl controls. These findings were associated with decreased actin polymerization and increased infiltration of innate myeloperoxidase-expressing immune cells, confirmed as neutrophils by flow cytometry, but more bacterial dissemination deep into colonic crypts. Further evaluation of the immune population recruited to the mucosa in response to C. rodentium revealed that loss of Tln1 in colonic epithelial cells (CECs) results in impaired recruitment and activation of T cells. C. rodentium infection-induced colonic mucosal hyperplasia was exacerbated in Tln1Δepi mice compared to littermate controls. We demonstrate that this is associated with decreased CEC apoptosis and crowding of proliferating cells in the base of the glands. Taken together, talin-1 expression by CECs is important in the regulation of both epithelial renewal and the inflammatory T cell response in the setting of colitis caused by C. rodentium, suggesting that this protein functions in CECs to limit, rather than contribute to the pathogenesis of this enteric infection.

Food Peptides, Gut Microbiota Modulation, and Antihypertensive Effects

The gut microbiota is increasingly important in the overall human health and as such, it is a target in the search of novel strategies for the management of metabolic disorders including blood pressure, and cardiovascular diseases. The link between microbiota and hypertension is complex and this review is intended to provide an overview of the mechanism including the production of postbiotics, mitigation of inflammation, and the integration of food biological molecules within this complex system. The focus is on hydrolyzed food proteins and peptides which are less commonly investigated for prebiotic properties. The analysis of available data showed that food peptides are multifunctional and can prevent gut dysbiosis by positively affecting the production of postbiotics or gut metabolites (short-chain fatty acids, polysaccharides, biogenic amines, bile acids). Peptides and the postbiotics then displayed antihypertensive effects via the renin-angiotensin system, the gut barrier, the endothelium, and reduction in inflammation and oxidative stress. Despite the promising antihypertensive effect of the food peptides via the modulation of the gut, there is a lack of human studies as most of the works have been conducted in animal models.

The association of dietary spermidine with all-cause mortality and CVD mortality: The U.S. National Health and Nutrition Examination Survey, 2003 to 2014

Background

Current studies on the protective effects of dietary spermidine (SPD) on cardiovascular disease (CVD) are mainly limited to animal studies, and the relationship between dietary SPD and CVD mortality remains inconclusive.

Objective

This study aims to evaluate the association between dietary SPD intake and CVD and all-cause mortality.

Methods

A total of 23,894 people enrolled in the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2014 were recruited for this study. The dietary intake of SPD from 11 specific food origins and total SPD was categorized into tertiles or quartiles. Cox proportional hazard regression models were developed to evaluate the association of SPD intake with CVD and all-cause mortalities.

Results

Among the 23,894 participants, 2,365 deaths, including 736 deaths due to CVD, were documented. After adjustment for potential confounders, compared with participants in the lowest quartile, participants in the highest quartile of total SPD had a significantly lower risk of CVD mortality (HR = 0.68, 95% CI: 0.51-0.91) and all-cause mortality (HR = 0.70, 95% CI: 0.60-0.82); participants in the highest tertiles or quartiles of vegetable-derived SPD, cereal-derived SPD, legume-derived SPD, nut-derived SPD, and cheese-derived SPD had a lower risk of CVD mortality (HR _{vegetable - derivedSPD} = 0.68, 95% CI: 0.54-0.86; HR _{cereal - derivedSPD} = 0.75, 95% CI: 0.57-0.97; HR _{legume - derivedSPD} = 0.68, 95% CI: 0.52-0.88; HR _{nut - derivedSPD} = 0.66, 95% CI: 0.53-0.80; HR _{cheese - derivedSPD} = 0.68, 95% CI: 0.52-0.88) and all-cause mortality (HR _{vegetable - derivedSPD} = 0.73, 95% CI: 0.64-0.84; HR _{cereal - derivedSPD} = 0.80, 95% CI: 0.69-0.93; HR _{legume - derivedSPD} = 0.70, 95% CI: 0.60-0.80;HR _{nut - derivedSPD} = 0.72, 95% CI: 0.64-0.81; HR _{cheese - derivedSPD} = 0.70, 95% CI: 0.61-0.81) than those in the lowest tertiles or quartiles. Moreover, subgroup analysis showed consistent associations among the people with hypertension and hyperlipidemia.

Conclusion

Higher intake of dietary SPD is associated with decreased risk of CVD and all-cause mortality, and among specific food origin SPD, SPD derived from vegetables, cereals, legumes, nuts, and cheese was associated with reduced CVD and all-cause mortality.

SOX15 transcriptionally increases the function of AOC1 to modulate ferroptosis and progression in prostate cancer

Amine oxidase copper-containing 1 (AOC1) is considered an oncogene in many types of tumors. Nevertheless, there have been no investigations of AOC1 and its regulatory mechanism in prostate cancer. Here, we reveal a novel action of AOC1 and a tumor suppressor mechanism in prostate cancer. AOC1 is downregulated in prostate cancer. Abatement of AOC1 in prostate cancer tissue is positively correlated with the tumor size, lymph node metastasis, and Gleason score for prostate cancer. Conversely, high expression of AOC1 is significantly associated with reduced proliferation and migration in prostate cancer both in vitro and in vivo. We show that the anticancer effect of AOC1 is mediated by its action on spermidine which leads to the activation of reactive oxygen species and ferroptosis. AOC1 expression in prostate cancer is positively regulated by the transcription factor SOX15. Therefore, SOX15 can transcriptionally promote AOC1 expression and strengthen this effect. Targeting AOC1 and SOX15 may be promising for the treatment of prostate cancer.

Mitochondrial Dysfunction and Cardiovascular Disease: Pathophysiology and Emerging Therapies

Mitochondria ensure the supply of cellular energy through the production of ATP via oxidative phosphorylation. The alteration of this process, called mitochondrial dysfunction, leads to a reduction in ATP and an increase in the production of reactive oxygen species (ROS). Mitochondrial dysfunction can be caused by mitochondrial/nuclear DNA mutations, or it can be secondary to pathological conditions such as cardiovascular disease, aging, and environmental stress. The use of therapies aimed at the prevention/correction of mitochondrial dysfunction, in the context of the specific treatment of cardiovascular diseases, is a topic of growing interest. In this context, the data are conflicting since preclinical studies are numerous, but there are no large randomized studies.

Research Progress and Potential Applications of Spermidine in Ocular Diseases

Spermidine, a natural polyamine, exists in almost all human tissues, exhibiting broad properties like anti-aging, autophagy induction, anti-inflammation, anti-oxidation, cell proliferation activation, and ion channel regulation. Considering that spermidine is already present in human nutrition, recent studies targeting supplementing exogenous sources of this polyamine appear feasible. The protective role of spermidine in various systems has been illuminated in the literature, while recent progress of spermidine administration in ocular diseases remains to be clarified. This study shows the current landscape of studies on spermidine and its potential to become a promising therapeutic agent to treat ocular diseases: glaucoma, optic nerve injury, age-related macular degeneration (AMD), cataracts, dry eye syndrome, and bacterial keratitis. It also has the potential to become a potent biomarker to predict keratoconus (KC), cataracts, uveitis, glaucoma, proliferative diabetic retinopathy (PDR), proliferative vitreoretinopathy (PVR), and retinopathy of prematurity (ROP). We also summarize the routes of administration and the effects of spermidine at different doses.

A comprehensive review of spermidine: Safety, health effects, absorption and metabolism, food materials evaluation, physical and chemical processing, and bioprocessing

Spermidine, a natural autophagy inducer, has a variety of health effects, such as antitumor, antiaging, anti-inflammation, cardiovascular protection, and neuromodulation. It has been a hot topic in the field of food processing, and current research findings suggest that spermidine-rich foods may be used in intervention and prevention of age-related diseases. In this article, recent findings on the safety, health effects, absorption and metabolism of spermidine were reviewed, and advances in food processing, including the raw materials evaluation, physical and chemical processing, and biological processing of spermidine, were highlighted. In particular, the core metabolic pathways, key gene targets, and efficient metabolic engineering strategies involved in the biosynthesis of spermidine and its precursors were discussed. Moreover, limitations and future perspectives of spermidine research were proposed. The purpose of this review is to provide new insights on spermidine from its safety to its food processing, which will advance the commercial production and applications of spermidine-rich foods and nutraceuticals.

Serum Spermidine in Relation to Risk of Stroke: A Multilevel Study

The relationship between serum spermidine levels and future cardiovascular disease risk has not yet been well elucidated in the general population based on community studies. Using a nested case-control study, we estimated the association between serum spermidine level and future stroke. New stroke cases had higher baseline levels of spermidine than controls [182.8 (141.8–231.5) vs. 152.0 (124.3–193.0), P < 0.001]. After multivariable adjustment, individuals with spermidine ≥ 205.9 nmol/L (T3) higher risks of stroke (HR 5.02, 95% CI 1.58–16.02) with the lowest quartile (< 136.9 nmol/L) as reference. The association between serum spermidine levels and risk of stroke seemed to be consistent and was reproducible in our cross-sectional studies. In addition, comparisons of the areas under receiver operator characteristics curves confirmed that a model including spermidine had better discrimination than without (0.755 vs. 0.715, P = 0.04). Here we report a close relationship exists between serum spermidine levels and risk of stroke.

Nutraceutical and Dietary Strategies for Up-Regulating Macroautophagy

Macroautophagy is a “cell cleansing” process that rids cells of protein aggregates and damaged organelles that may contribute to disease pathogenesis and the dysfunctions associated with aging. Measures which boost longevity and health span in rodents typically up-regulate macroautophagy, and it has often been suggested that safe strategies which can promote this process in humans may contribute to healthful aging. The kinase ULK1 serves as a trigger for autophagy initiation, and the transcription factors TFEB, FOXO1, ATF4 and CHOP promote expression of a number of proteins which mediate macroautophagy. Nutraceutical or dietary measures which stimulate AMPK, SIRT1, eIF5A, and that diminish the activities of AKT and mTORC1, can be expected to boost the activities of these pro-autophagic factors. The activity of AMPK can be stimulated with the phytochemical berberine. SIRT1 activation may be achieved with a range of agents, including ferulic acid, melatonin, urolithin A, N1-methylnicotinamide, nicotinamide riboside, and glucosamine; correction of ubiquinone deficiency may also be useful in this regard, as may dietary strategies such as time-restricted feeding or intermittent fasting. In the context of an age-related decrease in cellular polyamine levels, provision of exogenous spermidine can boost the hypusination reaction required for the appropriate post-translational modification of eIF5A. Low-protein plant-based diets could be expected to increase ATF4 and CHOP expression, while diminishing IGF-I-mediated activation of AKT and mTORC1. Hence, practical strategies for protecting health by up-regulating macroautophagy may be feasible.

New Insights into the Roles and Mechanisms of Spermidine in Aging and Age-Related Diseases

High incidences of morbidity and mortality associated with age-related diseases among the elderly population are a socio-economic challenge. Aging is an irreversible and inevitable process that is a risk factor for pathological progression of diverse age-related diseases. Spermidine, a natural polyamine, plays a critical role in molecular and cellular interactions involved in various physiological and functional processes. Spermidine has been shown to modulate aging, suppress the occurrence and severity of age-related diseases, and prolong lifespan. However, the precise mechanisms through which spermidine exerts its anti-aging effects have not been established. In this review, we elucidate on the mechanisms and roles underlying the beneficial effects of spermidine in aging from a molecular and cellular perspective. Moreover, we provide new insights into the promising potential diagnostic and therapeutic applications of spermidine in aging and age-related diseases.

Targeting Cardiovascular Risk Factors Through Dietary Adaptations and Caloric Restriction Mimetics

The average human life expectancy continues to rise globally and so does the prevalence and absolute burden of cardiovascular disease. Dietary restriction promotes longevity and improves various cardiovascular risk factors, including hypertension, obesity, diabetes mellitus, and metabolic syndrome. However, low adherence to caloric restriction renders this stringent dietary intervention challenging to adopt as a standard practice for cardiovascular disease prevention. Hence, alternative eating patterns and strategies that recapitulate the salutary benefits of caloric restriction are under intense investigation. Here, we first provide an overview of alternative interventions, including intermittent fasting, alternate-day fasting and the Mediterranean diet, along with their cardiometabolic effects in animal models and humans. We then present emerging pharmacological alternatives, including spermidine, NAD+ precursors, resveratrol, and metformin, as promising caloric restriction mimetics, and briefly touch on the mechanisms underpinning their cardiometabolic and health-promoting effects. We conclude that implementation of feasible dietary approaches holds the promise to attenuate the burden of cardiovascular disease and facilitate healthy aging in humans.

Bacterial-Induced Blood Pressure Reduction: Mechanisms for the Treatment of Hypertension via the Gut

Hypertension is a major risk factor for the development of cardiovascular disease. As more research into the gut microbiome emerges, we are finding increasing evidence to support that these microbes may have significant positive and negative effects on blood pressure and associated disorders. The bacterial-derived metabolites that are produced in the gut are capable of widespread effects to several tissue types and organs in the body. It is clear that the extensive metabolic function that is lost with gut dysbiosis is unlikely to be replenished with a single metabolite or bacterial strain. Instead, combinations of bacteria and concomitant therapies will provide a more well-rounded solution to manage hypertension. The bioactive molecules that are recognized in this review will inform on ideal characteristics of candidate bacteria and provide direction for future research on the gut microbiome in hypertension.

Dual Role of Mitophagy in Cardiovascular Diseases

ABSTRACT

Mitophagy is involved in the development of various cardiovascular diseases, such as atherosclerosis, heart failure, myocardial ischemia/reperfusion injury, and hypertension. Mitophagy is essential for maintaining intracellular homeostasis and physiological function in most cardiovascular origin cells, such as cardiomyocytes, endothelial cells, and vascular smooth muscle cells. Mitophagy is crucial to ensuring energy supply by selectively removing dysfunctional mitochondria, maintaining a balance in the number of mitochondria in cells, ensuring the integrity of mitochondrial structure and function, maintaining homeostasis, and promoting cell survival. Substantial research has indicated a "dual" effect of mitophagy on cardiac function, with inadequate and increased mitochondrial degradation both likely to influence the progression of cardiovascular disease. This review summarizes the main regulatory pathways of mitophagy and emphasizes that an appropriate amount of mitophagy can prevent endothelial cell injury, vascular smooth muscle cell proliferation, macrophage polarization, and cardiomyocyte apoptosis, avoiding further progression of cardiovascular diseases.

Protective Effects of Spermidine Against Cirrhotic Cardiomyopathy in Bile Duct-Ligated Rats

Cirrhotic cardiomyopathy is a critical factor that causes morbidity and mortality in crucial conditions such as liver transplantation. In animal model, the common pathophysiologic mechanisms of cirrhotic cardiomyopathy are similar to those associated with bile duct ligation (BDL). Overproduction of inflammatory and oxidant markers plays a crucial role in cirrhotic cardiomyopathy. Spermidine, a multifunctional polyamine, is known for its antioxidant and anti-inflammatory effects. In this study, we investigated the effects of spermidine on development of cirrhotic cardiomyopathy in BDL rats. Rats were randomly housed in 6 groups. Except the normal and sham groups, BDL was performed for all the control and spermidine groups. Seven days after operation, 3 different doses of spermidine (5, 10 and 50 mg/kg) were administrated until day 28, in spermidine groups. At the end of the fourth week, the electrocardiography (ECG) and papillary muscle isolation were performed. The serum level of tumor necrosis factor-a (TNF-α), interleukin-1β (IL-1β), and IL-10 and cardiac level of superoxide dismutase, glutathione (GSH). and malondialdehyde (MDA) were assessed. Furthermore, the nuclear factor-κB (NF-κB) expression was assessed by western blot. Cardiac histopathological changes were monitored. The serum levels of magnesium (Mg) and potassium (K) were investigated. Control group, exhibited exaggerated signs of cirrhotic cardiomyopathy in comparison with the sham group. Co-administration of spermidine at the dose of 10 mg/kg in BDL rats significantly improved the cardiac condition, reduced the inflammatory mediators, and increased antioxidant enzymes. In addition, the histopathologic findings were in accordance with the other results of the study. Besides, there was no significant alteration in serum levels of Mg and K. This study demonstrates that spermidine at the dose of 10 mg/kg significantly improved the cirrhotic cardiomyopathy in BDL model in rats.

Spermidine Inhibits Joints Inflammation and Macrophage Activation in Mice with Collagen-Induced Arthritis

Purpose

Spermidine (SPD) is a naturally occurring polyamine. In this study, we examined the role and possible mechanism of SPD in collagen-induced arthritis (CIA) mice.

Materials and Methods

CIA mice were intraperitoneally injected with SPD (2 and 50 mg/kg), dexamethasone (0.5 mg/kg), or saline daily for 21 days. The severity of the disease and inflammatory responses in the serum and joint tissue were assessed through macroscopic, immunohistochemical, and histological analyses.

Results

Macroscopic and histological results indicated that SPD protected against the development of CIA. SPD suppressed the levels of the pro-inflammatory cytokines IL-6 and IL-1β and increased the levels of the anti-inflammatory factor IL-10 in the serum. Immunohistochemical staining showed that 50 mg/kg SPD inhibited iNOS expression in synovial macrophages in the ankle joints of CIA mice.

Conclusion

These results suggest that SPD may protect CIA mice by inhibiting the polarization of M1 macrophages in the synovial tissue, reducing pro-inflammatory cytokines, and promoting anti-inflammatory factor release.

Spermidine induces cytoprotective autophagy of female germline stem cells in vitro and ameliorates aging caused by oxidative stress through upregulated sequestosome-1/p62 expression

BACKGROUND

Autophagy is required for oogenesis and plays a critical role in response to aging caused by oxidative stress. However, there have been no reports on regulation of cytoprotective autophagy in female germline stem cells (FGSCs) in response to aging caused by oxidative stress.

RESULTS

We found that Spermidine (SPD) significantly increased protein expression of autophagy markers microtubule-associated protein 1 light chain 3 beta-II (MAP1LC3B-II/LC3B-II) and sequestosome-1/p62 (SQSTM1/p62), and evoked autophagic flux in FGSCs. Moreover, SPD increased the number and viability of FGSCs in vitro. Further, we found that SPD significantly reduced basal or hydrogen peroxide (H₂O₂)-induced up-regulated protein expression of the aging markers, cyclin dependent kinase inhibitor 2A (p16/CDKN2A) and tumor protein 53 (p53). After knockdown of p62 in FGSCs, p16 protein levels were significant higher compared with controls. However, protein p16 levels were not significantly changed in p62 knockdown FGSCs with SPD treatment compared with without SPD. Moreover, SPD significantly changed the expression of autophagy-related genes and pathways in FGSCs, as shown by bioinformatics analysis of RNA sequencing data. Additionally, SPD significantly inhibited AKT/mTOR phosphorylation.

CONCLUSIONS

SPD induces cytoprotective autophagy in FGSCs in vitro and ameliorates cellular senescence of FGSCs induced by H₂O₂. Furthermore, SPD can ameliorate cellular senescence of FGSCs through p62. SPD might induce autophagy in FGSCs via the PI3K/Akt pathway. Our findings could be helpful for delaying aging of female germ cells due to oxidative stress and preserving female fertility.

The role of autophagy in cardiovascular pathology

Macroautophagy/autophagy is a conserved catabolic recycling pathway in which cytoplasmic components are sequestered, degraded, and recycled to survive various stress conditions. Autophagy dysregulation has been observed and linked with the development and progression of several pathologies, including cardiovascular diseases, the leading cause of death in the developed world. In this review, we aim to provide a broad understanding of the different molecular factors that govern autophagy regulation and how these mechanisms are involved in the development of specific cardiovascular pathologies, including ischemic and reperfusion injury, myocardial infarction, cardiac hypertrophy, cardiac remodeling, and heart failure.

The Role and Mechanism of Intestinal Flora in Blood Pressure Regulation and Hypertension Development

Significance: Hypertension (HTN) has a complex etiology that is characterized by genetic and environmental factors. It has become a global health burden leading to cardiovascular diseases and kidney diseases, ultimately progressing to premature death. Accumulating evidence indicated that gut microbiome was associated with metabolic disorders and inflammation, which were closely linked to HTN. Recent Advances: Recent studies using bacterial genomic analysis and fecal microbiota transplantation as well as many lines of seminal evidence demonstrated that aberrant gut microbiome was significantly associated with HTN. The intestinal microbiome of both patients and animals with HTN had decreased bacterial diversity, disordered microbial structure and functions, and altered end products of fermentation. Gut dysbiosis and metabolites of the gut microbiota play an important role in blood pressure (BP) control, and they are therefore responsible for developing HTN. Critical Issues: This study aimed at focusing on the recent advances in understanding the role played by gut bacteria and the mechanisms underlying the pathological milieu that induced elevated BP and led to HTN pathogenesis. Potential intervention strategies targeting the correction of gut dysbiosis to improve HTN development were summarized. Future Directions: Larger numbers of fecal transplants from participants with HTN should be carried out to examine the magnitude of BP changes with the replacement of the gut microbiome. The proposed mechanisms for the gut in regulating BP remain to be verified. Whether intervention strategies using probiotics, dietary interventions, bacteriophages, and fecal transplants are feasible for individuals with HTN remains to be explored. Antioxid. Redox Signal. 34, 811-830.

Inflammation, Nitro-Oxidative Stress, Impaired Autophagy, and Insulin Resistance as a Mechanistic Convergence Between Arterial Stiffness and Alzheimer's Disease

The average age of the world's elderly population is steadily increasing. This unprecedented rise in the aged world population will increase the prevalence of age-related disorders such as cardiovascular disease (CVD) and neurodegeneration. In recent years, there has been an increased interest in the potential interplay between CVDs and neurodegenerative syndromes, as several vascular risk factors have been associated with Alzheimer's disease (AD). Along these lines, arterial stiffness is an independent risk factor for both CVD and AD. In this review, we discuss several inflammaging-related disease mechanisms including acute tissue-specific inflammation, nitro-oxidative stress, impaired autophagy, and insulin resistance which may contribute to the proposed synergism between arterial stiffness and AD.

Mitochondrial tRNA Mutation and Regulation of the Adiponectin Pathway in Maternally Inherited Hypertension in Chinese Han

Some essential hypertension (EH) patients show maternal inheritance, which is the mode of mitochondrial DNA inheritance. This study examines the mechanisms by which mitochondrial mutations cause EH characterized by maternal inheritance. The study enrolled 115 volunteers, who were divided into maternally inherited EH (group A, n = 17), non-maternally inherited EH (group B, n = 65), and normal control (group C, n = 33) groups. A mitochondrial tRNA (15910 C>T) gene mutation was significantly correlated with EH and may play an important role in the pathogenesis of maternally inherited EH. Examining two families carrying the mitochondrial tRNA 15910 C>T mutation, which disrupted base pairing and may affect the stability and function of mitochondrial tRNA^Thr, we find that the overall incidence of EH was 59.3% in the maternal family members and 90% in males, significantly higher than in the general population in China (23.2%), and that the EH began at a younger age in those carrying mitochondrial tRNA 15910 C>T. To reveal the mechanism through which mitochondrial tRNA 15910 C>T causes maternally inherited EH, we cultured human peripheral blood mononuclear cells from family A2 in vitro. We find that cells carrying mitochondrial tRNA 15910 C>T were more viable and proliferative, and the increased ATP production resulted in raised intracellular reactive oxygen species (ROS). Moreover, the mitochondrial dysfunction resulted in reduced APN levels, causing hypoadiponectinemia, which promoted cell proliferation, and produced more ROS. This vicious cycle promoted the occurrence of EH with maternally inherited mitochondrial tRNA 15910 C>T. The mitochondrial tRNA 15910 C>T mutation may induce hypertension by changing the APN, AdipoR1, PGC-1α, and ERRα signaling pathways to elevate blood pressure. We discover a new mitochondrial mutation (tRNA 15910 C>T) related to EH, reveal part of the mechanism by which mitochondrial mutations lead to the occurrence and development of maternally inherited EH, and discuss the role of APN in it.

Targeting Mitophagy in Alzheimer's Disease

Mitochondria perform many essential cellular functions including energy production, calcium homeostasis, transduction of metabolic and stress signals, and mediating cell survival and death. Maintaining viable populations of mitochondria is therefore critical for normal cell function. The selective disposal of damaged mitochondria, by a pathway known as mitophagy, plays a key role in preserving mitochondrial integrity and quality. Mitophagy reduces the formation of reactive oxygen species and is considered as a protective cellular process. Mitochondrial dysfunction and deficits of mitophagy have important roles in aging and especially in neurodegenerative disorders such as Alzheimer's disease (AD). Targeting mitophagy pathways has been suggested to have potential therapeutic effects against AD. In this review, we aim to briefly discuss the emerging concepts on mitophagy, molecular regulation of the mitophagy process, current mitophagy detection methods, and mitophagy dysfunction in AD. Finally, we will also briefly examine the stimulation of mitophagy as an approach for attenuating neurodegeneration in AD.

Spermidine, an autophagy inducer, as a therapeutic strategy in neurological disorders

Spermidine is a naturally occurring endogenous polyamine synthesized from diamine putrescine. It is a well-known autophagy inducer that maintains cellular and neuronal homeostasis. Healthy brain development and function are dependent on brain polyamine concentration. Polyamines interact with the opioid system, glutamatergic signaling and neuroinflammation in the neuronal and glial compartments. Among the polyamines, spermidine is found highest in the human brain. Age-linked fluctuations in the spermidine levels may possibly contribute to the impairments in neural network and neurogenesis. Exogenously administered spermidine helps in the treatment of brain diseases. Further, current studies highlight the ability of spermidine to promote longevity by inducing autophagy. Still, the causal neuroprotective mechanism of spermidine in neuronal dysfunction remains unidentified. This review aims to summarize various neuroprotective effects of spermidine related to anti-aging/ anti-inflammatory properties and the prevention of neurotoxicity that helps in achieving beneficial effects in age-related neurological disorder. We also expose the signaling cascades modulated by spermidine which might result in therapeutic action. The present review highlights clinical studies along with in-vivo and in-vitro preclinical studies to provide a new dimension for the therapeutic potential of spermidine in neurological disorders.

Defective Autophagy in Vascular Smooth Muscle Cells Alters Vascular Reactivity of the Mouse Femoral Artery

Autophagy is an important cellular survival process that enables degradation and recycling of defective organelles and proteins to maintain cellular homeostasis. Hence, defective autophagy plays a role in many age-associated diseases, such as atherosclerosis, arterial stiffening and hypertension. Recently, we showed in mice that autophagy in vascular smooth muscle cells (VSMCs) of large elastic arteries such as the aorta is important for Ca²⁺ mobilization and vascular reactivity. Whether autophagy plays a role in the smaller muscular arteries, such as the femoral artery, and thereby contributes to for example, blood pressure regulation is currently unknown. Therefore, we determined vascular reactivity of femoral artery segments of mice containing a VSMC specific deletion of the essential autophagy gene Atg7 (Atg7^F/F SM22α-Cre⁺) and compared them to femoral artery segments of corresponding control mice (Atg7^+/+ SM22α-Cre⁺). Our results indicate that similar to the aorta, femoral artery segments showed enhanced contractility. Specifically, femoral artery segments of Atg7^F/F SM22α-Cre⁺ mice showed an increase in phasic phenylephrine (PE) induced contractions, together with an enhanced sensitivity to depolarization induced contractions. In addition, and importantly, VSMC sensitivity to exogenous nitric oxide (NO) was significantly increased in femoral artery segments of Atg7^F/F SM22α-Cre⁺ mice. Notwithstanding the fact that small artery contractility is a significant pathophysiological determinant for the development of hypertension, 7 days of treatment with angiotensin II (AngII), which increased systolic blood pressure in control mice, was ineffective in Atg7^F/F SM22α-Cre⁺ mice. It is likely that this was due to the increased sensitivity of VSMCs to NO in the femoral artery, although changes in the heart upon AngII treatment were also present, which could also be (partially) accountable for the lack of an AngII-induced rise in blood pressure in Atg7^F/F SM22α-Cre⁺ mice. Overall, our study indicates that apart from previously shown effects on large elastic arteries, VSMC autophagy also plays a pivotal role in the regulation of the contractile and relaxing properties of the smaller muscular arteries. This may suggest a role for autophagy in vascular pathologies, such as hypertension and arterial stiffness.

Mitochondrial dysfunction in cardiovascular disease: Current status of translational research/clinical and therapeutic implications

Mitochondria provide energy to the cell during aerobic respiration by supplying ~95% of the adenosine triphosphate (ATP) molecules via oxidative phosphorylation. These organelles have various other functions, all carried out by numerous proteins, with the majority of them being encoded by nuclear DNA (nDNA). Mitochondria occupy ~1/3 of the volume of myocardial cells in adults, and function at levels of high-efficiency to promptly meet the energy requirements of the myocardial contractile units. Mitochondria have their own DNA (mtDNA), which contains 37 genes and is maternally inherited. Over the last several years, a variety of functions of these organelles have been discovered and this has led to a growing interest in their involvement in various diseases, including cardiovascular (CV) diseases. Mitochondrial dysfunction relates to the status where mitochondria cannot meet the demands of a cell for ATP and there is an enhanced formation of reactive-oxygen species. This dysfunction may occur as a result of mtDNA and/or nDNA mutations, but also as a response to aging and various disease and environmental stresses, leading to the development of cardiomyopathies and other CV diseases. Designing mitochondria-targeted therapeutic strategies aiming to maintain or restore mitochondrial function has been a great challenge as a result of variable responses according to the etiology of the disorder. There have been several preclinical data on such therapies, but clinical studies are scarce. A major challenge relates to the techniques needed to eclectically deliver the therapeutic agents to cardiac tissues and to damaged mitochondria for successful clinical outcomes. All these issues and progress made over the last several years are herein reviewed.

Mitochondrial oxidative injury: a key player in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has become the most prevalent liver disease worldwide. NAFLD is tightly linked to the metabolic syndrome, insulin resistance, and oxidative stress. Globally, its inflammatory form, nonalcoholic steatohepatitis (NASH), has become the main cause of liver-related morbidity and mortality, mainly due to liver cirrhosis and primary liver cancer. One hallmark of NASH is the presence of changes in mitochondrial morphology and function that are accompanied by a blocked flow of electrons in the respiratory chain, which increases formation of mitochondrial reactive oxygen species in a self-perpetuating vicious cycle. Consequences are oxidation of DNA bases and mitochondrial DNA depletion that are coupled with genetic and acquired mitochondrial DNA mutations, all impairing the resynthesis of respiratory chain polypeptides. In general, several maladaptations of pathways that usually maintain energy homeostasis occur with the early and late excess metabolic stress in NAFLD and NASH. We discuss the interplay between hepatocyte mitochondrial stress and inflammatory responses, focusing primarily on events initiated and maintained by mitochondrial free radical-induced damage in NAFLD. Importantly, mitochondrial oxidative stress and dysfunction are modulated by key pharmacological targets that are related to excess production of reactive oxygen species, mitochondrial turnover and the mitochondrial unfolded protein response, mitophagy, and mitochondrial biogenesis. However, the efficacy of such interventions depends on NAFLD/NASH disease stage.

Spermidine activates RIP1 deubiquitination to inhibit TNF-α-induced NF-κB/p65 signaling pathway in osteoarthritis

Spermidine has been known to inhibit the production of pro-inflammatory cytokines. However, there are no reports about anti-inflammatory effects of spermidine on osteoarthritis (OA). Herein, we examined whether OA progression could be delayed by intraperitoneal injection (i.p.) of spermidine in the anterior cruciate ligament transection (ACLT) and TNF-α induced arthritis (TIA) mouse models. During the process, human FLS cells (H-FLS) were used to investigate the potential ubiquitination mechanism of spermidine-mediated RIP1 in TNF-α-induced NF-κB/p65 signaling. We found that spermidine attenuated synovitis, cartilage degeneration and osteophyte formation, resulting in substantially lower OARSI scores and TNF-α scores in spermidine-treated ACLT and TIA mice. In terms of the mechanism, 9 μM spermidine did not affect the viability, proliferation, cell cycle and apoptosis of H-FLS, and exerted inhibitory effects by activating CYLD-mediated RIP1 deubiquitination on TNF-α-induced NF-κB/p65 signaling in H-FLS. From these data, we can conclude that spermidine attenuates OA progression by the inhibition of TNF-α-induced NF-κB pathway via the deubiquitination of RIP1 in FLS. Therefore, intake of spermidine could be a potential therapy for preventing OA.

Spermidine intake is associated with cortical thickness and hippocampal volume in older adults

BACKGROUND

The natural polyamine spermidine, known to be important for cellular function, decreases during aging. Previous research has demonstrated beneficial impact of spermidine intake on memory functions in both animal models and humans, suggesting that spermidine may be a preventive approach to delay age-related cognitive decline and possibly even Alzheimer's disease (AD). However, the association of spermidine intake with brain health in humans is still unknown. In this study, we aimed to determine the association between dietary spermidine intake and structural brain measures in older individuals with subjective cognitive decline (SCD) and healthy controls (HC).

METHODS

Dietary spermidine intake and adherence to Mediterranean Diet (MeDi) were assessed by a self-reported food frequency questionnaire in 90 older adults with SCD and 47 HC. Processing of structural MRI data yielded global brain volumes, hippocampal volume, mean and regional cortical thickness, and cortical thickness in a template encompassing AD-vulnerable regions. In exploratory analyses, the association between spermidine intake and structural brain measures was assessed using adjusted and unadjusted linear regression models. Additionally, we tested for differential associations as a function of group. Mediation analyses were performed to examine whether dietary spermidine intake mediates the associations between adherence to MeDi and structural brain measures.

RESULTS

Higher spermidine intake was associated with larger hippocampal volume (standardized β ​= ​0.262, p ​= ​0.002), greater mean cortical thickness (standardized β ​= ​0.187, p ​= ​0.031), and greater cortical thickness in AD-vulnerable brain regions (standardized β ​= ​0.176, p ​= ​0.042), the parietal (standardized β ​= ​0.202, p ​= ​0.020), and temporal lobes (standardized β ​= ​0.217, p ​= ​0.012). No significant differential effect emerged between older adults with SCD and HC. Moreover, a substantial mediating effect of dietary spermidine intake on the associations between adherence to MeDi and structural brain measures was observed.

CONCLUSION

Higher dietary spermidine intake was positively associated with several structural brain measures, irrespective of the presence of SCD, and substantially mediated the relationship of adherence to MeDi and structural brain measures. Our data suggest that higher spermidine intake might be a promising dietary approach to preserve brain health in older adults, a hypothesis currently tested in an interventional trial.

Spermidine as a target for cancer therapy

Spermidine, as a natural component from polyamine members, is originally isolated from semen and also existed in many natural plants, and can be responsible for cell growth and development in eukaryotes. The supplementation of spermidine can extend health and lifespan across species. Although the elevated levels of polyamines and the regulation of rate-limiting enzymes for polyamine metabolism have been identified as the biomarkers in many cancers, recent epidemiological data support that an increased uptake of spermidine as a caloric restriction mimic can reduce overall mortality associated with cancers. The possible mechanisms between spermidine and cancer development may be related to the precise regulation of polyamine metabolism, anti-cancer immunosurveillance, autophagy, and apoptosis. Increased intake of polyamine seems to suppress tumorigenesis, but appears to accelerate the growth of established tumors. Based on these observations and the absolute requirement for polyamines in tumor growth, spermidine could be a rational target for chemoprevention and clinical therapeutics of cancers.

Autophagy in cardiovascular health and disease

Autophagy is a cellular housekeeping and quality control mechanism that is essential for homeostasis and survival. By virtue of this role, any perturbations to the flow of this process in cardiac or vascular cells can elicit harmful effects on the cardiovascular system, and subsequently affect whole organismal health. In this chapter, we summarize the preclinical evidence supporting the role of autophagy in sustaining cardiovascular health during homeostasis and disease. Furthermore, we discuss how autophagy activation by dietary, genetic and pharmaceutical interventions can be exploited to counteract common cardiovascular disorders, including atherosclerosis, coronary artery disease, diabetic cardiomyopathy, arrhythmia, chemotherapy-induced cardiotoxicity and heart failure.

Identification of a Spermidine Synthase Gene from Soybean by Recombinant Expression, Transcriptional Verification, and Sequence Analysis

Spermidine possesses multiple healthy functions, and soybeans contain the most abundant spermidine. In this study, spermidine contents of soybeans from different varieties and production regions in China were evaluated, and a spermidine synthase gene (speE) was identified by recombinant expression, transcriptional verification, and sequence analysis. Spermidine contents of soybean samples from 18 varieties ranged 72.38-228.82 mg/kg, and those from 19 production regions ranged 134.64-242.32 mg/kg. The highest-spermidine sample GZ was used to clone four predicted speE genes. Expressing the gene speE5 improved the spermidine titer by 54% in Bacillus amyloliquefaciens, confirming that speE5 was involved in spermidine synthesis. Transcriptional verification was performed through a soybean germination model. Germination for 48 h led to a onefold increase of spermidine in samples SHX and HB, and corresponding speE5 transcriptional levels were improved by 26-fold and 18-fold, respectively, further verifying the function of speE5. Finally, the sequences of the speE5 gene and deduced amino acids were analyzed, and the conserved sites and catalysis mechanisms were presented. This study identified an active spermidine synthase gene from soybean for the first time, which provided an important gene resource for genetic breeding of spermidine-rich soybean or microbial cell factory.

Autophagy as an emerging therapeutic target for age-related vascular pathologies

Introduction: The incidence of age-related vascular diseases such as arterial stiffness, hypertension and atherosclerosis, is rising dramatically and is substantially impacting healthcare systems. Mounting evidence suggests that there is an important role for autophagy in maintaining (cardio)vascular health. Impaired vascular autophagy has been linked to arterial aging and the initiation of vascular disease.Areas covered: The function and implications of autophagy in vascular smooth muscle cells and endothelial cells are discussed in healthy blood vessels and arterial disease. Furthermore, we discuss current treatment options for vascular disease and their links with autophagy. A literature search was conducted in PubMed up to October 2019.Expert opinion: Although the therapeutic potential of inducing autophagy in age-related vascular pathologies is considerable, several issues should be addressed before autophagy induction can be clinically used to treat vascular disease. These issues include uncertainty regarding the most effective drug target as well as the lack of potency and selectivity of autophagy inducing drugs. Moreover, drug tolerance or autophagy mediated cell death have been reported as possible adverse effects. Special attention is required for determining the cause of autophagy deficiency to optimize the treatment strategy.

Targeting mitochondria for cardiovascular disorders: therapeutic potential and obstacles

A large body of evidence indicates that mitochondrial dysfunction has a major role in the pathogenesis of multiple cardiovascular disorders. Over the past 2 decades, extraordinary efforts have been focused on the development of agents that specifically target mitochondria for the treatment of cardiovascular disease. Despite such an intensive wave of investigation, no drugs specifically conceived to modulate mitochondrial functions are currently available for the clinical management of cardiovascular disease. In this Review, we discuss the therapeutic potential of targeting mitochondria in patients with cardiovascular disease, examine the obstacles that have restrained the development of mitochondria-targeting agents thus far, and identify strategies that might empower the full clinical potential of this approach.

Autophagy in Cardiovascular Aging

Cardiovascular diseases are the most prominent maladies in aging societies. Indeed, aging promotes the structural and functional declines of both the heart and the blood circulation system. In this review, we revise the contribution of known longevity pathways to cardiovascular health and delineate the possibilities to interfere with them. In particular, we evaluate autophagy, the intracellular catabolic recycling system associated with life- and health-span extension. We present genetic models, pharmacological interventions, and dietary strategies that block, reduce, or enhance autophagy upon age-related cardiovascular deterioration. Caloric restriction or caloric restriction mimetics like metformin, spermidine, and rapamycin (all of which trigger autophagy) are among the most promising cardioprotective interventions during aging. We conclude that autophagy is a fundamental process to ensure cardiac and vascular health during aging and outline its putative therapeutic importance.

Protein-Protein Interaction Network Analysis Reveals Several Diseases Highly Associated with Polycystic Ovarian Syndrome

Based on clinical observations, women with polycystic ovarian syndrome (PCOS) are prone to developing several other diseases, such as metabolic and cardiovascular diseases. However, the molecular association between PCOS and these diseases remains poorly understood. Recent studies showed that the information from protein-protein interaction (PPI) network analysis are useful in understanding the disease association in detail. This study utilized this approach to deepen the knowledge on the association between PCOS and other diseases. A PPI network for PCOS was constructed using PCOS-related proteins (PCOSrp) obtained from PCOSBase. MCODE was used to identify highly connected regions in the PCOS network, known as subnetworks. These subnetworks represent protein families, where their molecular information is used to explain the association between PCOS and other diseases. Fisher's exact test and comorbidity data were used to identify PCOS-disease subnetworks. Pathway enrichment analysis was performed on the PCOS-disease subnetworks to identify significant pathways that are highly involved in the PCOS-disease associations. Migraine, schizophrenia, depressive disorder, obesity, and hypertension, along with twelve other diseases, were identified to be highly associated with PCOS. The identification of significant pathways, such as ribosome biogenesis, antigen processing and presentation, and mitophagy, suggest their involvement in the association between PCOS and migraine, schizophrenia, and hypertension.

Aspirin Recapitulates Features of Caloric Restriction

The age-associated deterioration in cellular and organismal functions associates with dysregulation of nutrient-sensing pathways and disabled autophagy. The reactivation of autophagic flux may prevent or ameliorate age-related metabolic dysfunctions. Non-toxic compounds endowed with the capacity to reduce the overall levels of protein acetylation and to induce autophagy have been categorized as caloric restriction mimetics (CRMs). Here, we show that aspirin or its active metabolite salicylate induce autophagy by virtue of their capacity to inhibit the acetyltransferase activity of EP300. While salicylate readily stimulates autophagic flux in control cells, it fails to further increase autophagy levels in EP300-deficient cells, as well as in cells in which endogenous EP300 has been replaced by salicylate-resistant EP300 mutants. Accordingly, the pro-autophagic activity of aspirin and salicylate on the nematode Caenorhabditis elegans is lost when the expression of the EP300 ortholog cpb-1 is reduced. Altogether, these findings identify aspirin as an evolutionary conserved CRM.

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The aspirin metabolite, salicylate, competitively inhibits EP300 acetyltransferase

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EP300 inhibition is epistatic to autophagy induction by salicylate

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Aspirin triggers cardioprotective mitophagy in mice and nematodes

Gut Microbiota Plays a Central Role to Modulate the Plasma and Fecal Metabolomes in Response to Angiotensin II

Supplemental Digital Content is available in the text.

Gut microbial metabolites have been implicated in contributing to blood pressure regulation; however, only a few microbial metabolites have been examined to date. In this study, we hypothesized that an unbiased screen for changes in gut microbial metabolites in a chronic Ang II (angiotensin II) infusion model would identify novel microbial metabolites associated with blood pressure regulation. To accomplish this, we used both conventional and germ-free mice, which had been implanted with minipumps to infuse either saline or Ang II. Our aim was to identify metabolites that were altered with Ang II treatment in conventional mice, but not in germ-free mice, indicating that they are dependent on the gut microbiota. Both plasma and feces samples were processed and analyzed using liquid chromatography-tandem mass spectroscopy. In plasma, we identified 4 metabolites that were significantly upregulated and 8 metabolites that were significantly downregulated with Ang II treatment in conventional mice; none of these metabolites changed in germ-free mice. Similarly, in feces, we identified 25 metabolites that were significantly upregulated and 71 metabolites that were significantly downregulated with Ang II treatment in conventional mice; none of these metabolites changed in germ-free mice. Finally, fecal 16S sequencing revealed significant shifts in the microbiome of conventional mice with Ang II treatment, including sex-specific changes. These data demonstrate that the metabolites that are differentially regulated with Ang II are dependent on the gut microbiome.

Synthesis and Characterization of a Molecularly Imprinted Polymer of Spermidine and the Exploration of Its Molecular Recognition Properties

Spermidine is a functional ingredient that can extend the lifespan of many foods and indicate meat safety. However, its synthesis and enrichment is expensive and complex. To develop an effective separation material that can offer highly selective recognition of spermidine, we first applied non-covalent molecular imprinting technology using methacrylic acid as a functional monomer, azobisisobutyronitrile as an initiator, and ethylene glycol dimethacrylate as a cross-linker. The adsorption properties of the polymers were analyzed using the Scatchard equation, the Lagergren kinetic equation, and the static distribution coefficient. The optimal polymerization molar ratio of the template molecule spermidine to the functional monomer was 1:4, the maximum adsorption amount was 97.75 μmol/g, and the adsorption equilibrium time was 300 min. The selective experiment showed that the interfering substances tyramine and histamine had selectivity factor α values of 2.01 and 1.78, respectively, indicating that the prepared polymer had good spermidine recognition ability. The density function theory calculations showed that the hydrogen bond strength, steric effect, and product energy caused adsorption and separation differences among the different imprinted polymer complexes.

Conjugation with Phenylalanine Enhances Autophagy-Inducing Activity of (-)-Epigallocatechin Gallate in Hepatic Cells

Given the importance of (-)-epigallocatechin gallate (EGCG) as an autophagy-enhancing and thereby lipid-lowering agent, optimization of its activity warrants its therapeutic potential in the treatment of hepatic diseases as well as metabolic disorders. On the basis of our previous observations that structural modifications provided substantial improvements in the bioactivity of EGCG, we investigated the autophagy-enhancing activity of EGCG derivatives. Among 14 EGCG derivatives, E10 with a phenylalanine attached to the D ring of EGCG exhibited the most promising effects in stimulating autophagy in Huh7 cells, which was supported by several lines of evidence: (1) stimulation of autophagy revealed by an increased amount of LC3B-II (4.1 ± 0.8-fold compared to the control) as well as the 2.0 ± 0.1-fold activation of adenosine monophosphate-activated protein kinase in the presence of E10 and (2) E10-stimulated autophagic flux demonstrated by a 1.6 ± 0.4-fold increase in LC3B-II upon co-treatment with chloroquine, 38.1 ± 5.6% reduction of p62/SQSTM1, and an increase in the formation of autophagic compartments visualized by both CYTO-ID staining (3.0 ± 0.1-fold) and tandem RFP-GFP-LC3 fluorescence (2.7 ± 0.4- and 3.2 ± 0.3-fold for green and red fluorescence, respectively). Finally, the autophagy-inducing activity of E10 culminated in a 5.3-fold reduction of hepatic lipid accumulation caused by fatty acids. In all of the assay settings, E10 was consistently 1.3-3.5-fold more potent than EGCG. Taken together, we demonstrated a significant increase in autophagy-stimulating activity of EGCG through structural modifications.

Metabolic Stress, Autophagy, and Cardiovascular Aging: from Pathophysiology to Therapeutics

Recent advances in health care have improved the management of cardiometabolic disorders, and prolonged lifespan. However, the ever-rising prevalence of metabolic stress related to obesity (insulin resistance, diabetes, hypertension, and dyslipidemia) has greatly challenged geriatric care. The ubiquitin-proteasome system and autophagy-lysosomal pathways represent two major, yet distinct cellular machineries, for degradation and removal of damaged or long-lived proteins and organelles; the function of which declines with aging. To seek new strategies for cardiovascular aging under various metabolic diseases, it is imperative to understand the precise role for metabolic stress and protein quality control, in particular autophagy, in premature cardiovascular aging. Targeting metabolic stress and autophagy may offer exciting new avenues for the management of cardiovascular aging.

Mitochondria and Reactive Oxygen Species Contribute to Neurogenic Hypertension

Beyond its primary role as fuel generators, mitochondria are engaged in a variety of cellular processes, including redox homeostasis. Mitochondrial dysfunction, therefore, may have a profound impact on high-energy-demanding organs such as the brain. Here, we review the roles of mitochondrial biogenesis and bioenergetics, and their associated signaling in cellular redox homeostasis, and illustrate their contributions to the oxidative stress-related neural mechanism of hypertension, focusing on specific brain areas that are involved in the generation or modulation of sympathetic outflows to the cardiovascular system. We also highlight future challenges of research on mitochondrial physiology and pathophysiology.

Spermine Alleviates Acute Liver Injury by Inhibiting Liver-Resident Macrophage Pro-Inflammatory Response Through ATG5-Dependent Autophagy

Liver-resident macrophages (Kupffer cells, KCs) and autophagy play critical roles in the pathogenesis of toxin-induced liver injury. Recent evidence indicates that autophagy can regulate macrophage M1/M2 polarization under different inflammatory conditions. Polyamines, including putrescine, spermidine, and spermine (SPM), are polycations with anti-oxidative, anti-aging, and cell autophagy induction properties. This study aimed to determine the mechanisms by which SPM protects against thioacetamide (TAA)-induced acute liver injury in a mouse model. Pretreatment with SPM significantly alleviated liver injury and reduced intrahepatic inflammation in TAA-induced liver injury compared to controls. SPM markedly inhibited M1 polarization, but promoted M2 polarization of KCs obtained from TAA-exposed livers, as evidenced by decreased IL-1β and iNOS gene induction but increased Arg-1 and Mrc-1 gene induction accompanied by decreased STAT1 activation and increased STAT6 activation. Furthermore, pretreatment with SPM enhanced autophagy, as revealed by increased LC3B-II levels, decreased p62 protein expression, and increased ATG5 protein expression in TAA-treated KCs. Knockdown of ATG5 in SPM-pretreated KCs by siRNA resulted in a significant increase in pro-inflammatory TNF-α and IL-6 secretion and decreased anti-inflammatory IL-10 secretion after TAA treatment, while no significant changes were observed in cytokine production in the TAA treatment alone. Additionally, the effect of SPM on regulation of KC M1/M2 polarization was abolished by ATG5 knockdown in TAA-exposed KCs. Finally, in vivo ATG5 knockdown in KCs abrogated the protective effect of SPM against TAA-induced acute liver injury. Our results indicate that SPM-mediated autophagy inhibits M1 polarization, while promoting M2 polarization of KCs in TAA-treated livers via upregulation of ATG5 expression, leading to attenuated liver injury. This study provides a novel target for the prevention of acute liver injury.