Extension of the mitochondria dysfunction hypothesis of metabolic syndrome to atherosclerosis with emphasis on the endocrine-disrupting chemicals and biophysical laws

The role of SIRT2 in vascular-related and heart-related diseases: A review

At present, cardiovascular disease is one of the important factors of human death, and there are many kinds of proteins involved. Sirtuins family proteins are involved in various physiological and pathological activities of the human body. Among them, there are more and more studies on the relationship between sirtuin2 (SIRT2) protein and cardiovascular diseases. SIRT2 can effectively inhibit pathological cardiac hypertrophy. The effect of SIRT2 on ischaemia‐reperfusion injury has different effects under different conditions. SIRT2 can reduce the level of reactive oxygen species (ROS), which may help to reduce the severity of diabetic cardiomyopathy. SIRT2 can affect a variety of cardiovascular diseases, energy metabolism and the ageing of cardiomyocytes, thereby affecting heart failure. SIRT2 also plays an important role in vascular disease. For endothelial cell damage used by oxidative stress, the role of SIRT2 is bidirectional, which is related to the degree of oxidative stress stimulation. When the degree of stimulation is small, SIRT2 plays a protective role, and when the degree of stimulation increases to a certain level, SIRT2 plays a negative role. In addition, SIRT2 is also involved in the remodelling of blood vessels and the repair of skin damage.

Enterococcus faecalis sir2-like gene enhances aerobic metabolism of themselves and mitochondrial respiration of mammal cells to bring about improving metabolic syndrome through the PGC-1α pathway

Recent studies showed that probiotics could improve metabolic syndrome, making the identification of factors affecting metabolic control more important than ever. The mammalian sirtuin protein family has received much attention for its regulatory role, especially in various mitochondrial ATP, glucose, and lipid metabolic pathways. However, compared with the mammalian sirtuin protein family, the function of prokaryotic sir2 protein is much less known. We studied the effects of probiotics sir2 protein on cell energy metabolize pathway, which showed that deletion of Enterococcus faecalis sir2 inhibited the aerobic oxidation of bacteria and increased the bacterial fermentation. The study of EF-sir2 (sir2 protein of E. faecalis) role of molecular targets demonstrated that deacetylation of EF-sir2 was via Rho upregulating in E. faecalis. When transfected into HEK293T cells, EF-sir2 could significantly facilitate aerobic oxidation of glucose, enhance the respiration to generate more ATP, and cause upregulation of NRF1 target gene. Then, we found EF-sir2 could increase activity of PGC-1α by deacetylation and PGC-1α inhibition decreased the expression of NRF1 target gene. Finally, we demonstrated that EF-sir2 could significantly improve the metabolic index of mammalian cells through insulin resistanced model in vitro and metabolic syndrome rat model in vivo. Our results first revealed that prokaryotic sir2 genes affect the molecular mechanism of cellular metabolism and the regulatory of cell homeostasis in prokaryotic and mammalian cells, suggesting that EF-sir2 has a positive regulatory effect on metabolic disturbance and may be used for the prevention and treatment of pathological processes related to metabolic syndrome.

Childhood obesity and endocrine disrupting chemicals

The prevalence of obesity around the world has increased sharply. Strong evidence has emerged over the last decades that human exposure to numerous endocrine disrupting chemicals (EDCs) is the cause of obesity and obesity-related metabolic diseases. Many EDCs are manmade chemicals that are released into the environment. EDCs are exogenous compounds that interfere with hormonal regulation and normal endocrine systems, thereby affecting the health of animals and humans. The number of chemicals belonging to EDCs is increasing and some of them are very stable; they persist in the environment (persistent organic pollutants). Although they are banned, their concentrations have been continuously increasing over time. This review gives a brief introduction to common EDCs, and evidence of harmful effects of EDCs on obesity-related diseases; we focus in particular on EDCs' role in causing mitochondrial dysfunction.

Linking mitochondrial dysfunction, metabolic syndrome and stress signaling in Neurodegeneration

Mounting evidence suggests a link between metabolic syndrome (MetS) such as diabetes, obesity, non-alcoholic fatty liver disease in the progression of Alzheimer's disease (AD), Parkinson's disease (PD) and other neurodegenerative diseases (NDDs). For instance, accumulated Aβ oligomer is enhancing neuronal Ca²⁺ release and neural NO where increased NO level in the brain through post translational modification is modulating the level of insulin production. It has been further confirmed that irrespective of origin; brain insulin resistance triggers a cascade of the neurodegeneration phenomenon which can be aggravated by free reactive oxygen species burden, ER stress, metabolic dysfunction, neuorinflammation, reduced cell survival and altered lipid metabolism. Moreover, several studies confirmed that MetS and diabetic sharing common mechanisms in the progression of AD and NDDs where mitochondrial dynamics playing a critical role. Any mutation in mitochondrial DNA, exposure of environmental toxin, high-calorie intake, homeostasis imbalance, glucolipotoxicity is causative factors for mitochondrial dysfunction. These cumulative pleiotropic burdens in mitochondria leads to insulin resistance, increased ROS production; enhanced stress-related enzymes that is directly linked MetS and diabetes in neurodegeneration. Since, the linkup mechanism between mitochondrial dysfunction and disease phenomenon of both MetS and NDDs is quite intriguing, therefore, it is pertinent for the researchers to identify and implement the therapeutic interventions for targeting MetS and NDDs. Herein, we elucidated the pertinent role of MetS induced mitochondrial dysfunction in neurons and their consequences in NDDs. Further, therapeutic potential of well-known biomolecules and chaperones to target altered mitochondria has been comprehensively documented. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.

Metabolic syndrome and the environmental pollutants from mitochondrial perspectives

The worldwide epidemic of diabetes and metabolic syndrome in the last few decades cannot be fully accounted for only by changes in the lifestyle factors, such as sedentary lifestyle and overeating. Besides genetic factors, there must be other causes to explain this rapid change. They could not be infectious in nature and induce insulin resistance as key biochemical abnormality. Mitochondrial dysfunction could be underlying mechanism behind the insulin resistance, thus metabolic syndrome. Then there have been increasing number of reports suggesting that chronic exposure to and accumulation of endocrine disrupting chemicals (EDCs), especially so-called the persistent organic pollutants (POPs) within the body might be associated with metabolic syndrome. Combining two concepts, we developed new "EDCs-induced mitochondrial dysfunction hypothesis of metabolic syndrome". In this review we suggest that classifying those chemicals into 5 groups might be clinically useful considering their removal or avoidance; POPs, non-persistent organic pollutants, heavy metals, air pollutants and drugs. We will also discuss briefly how those insights could be applied to clinical medicine.