Regulation of SIRT3/FOXO1 Signaling Pathway in Rats with Non-alcoholic Steatohepatitis by Salvianolic Acid B

Supplementation of Silymarin Alone or in Combination with Salvianolic Acids B and Puerarin Regulates Gut Microbiota and Its Metabolism to Improve High-Fat Diet-Induced NAFLD in Mice

Silymarin, salvianolic acids B, and puerarin were considered healthy food agents with tremendous potential to ameliorate non-alcoholic fatty liver disease (NAFLD). However, the mechanisms by which they interact with gut microbiota to exert benefits are largely unknown. After 8 weeks of NAFLD modeling, C57BL/6J mice were randomly divided into five groups and fed a normal diet, high-fat diet (HFD), or HFD supplemented with a medium or high dose of Silybum marianum extract contained silymarin or polyherbal extract contained silymarin, salvianolic acids B, and puerarin for 16 weeks, respectively. The untargeted metabolomics and 16S rRNA sequencing were used for molecular mechanisms exploration. The intervention of silymarin and polyherbal extract significantly improved liver steatosis and recovered liver function in the mice, accompanied by an increase in probiotics like Akkermansia and Blautia, and suppressed Clostridium, which related to changes in the bile acids profile in feces and serum. Fecal microbiome transplantation confirmed that this alteration of microbiota and its metabolites were responsible for the improvement in NAFLD. The present study substantiated that alterations of the gut microbiota upon silymarin and polyherbal extract intervention have beneficial effects on HFD-induced hepatic steatosis and suggested the pivotal role of gut microbiota and its metabolites in the amelioration of NAFLD.

Qishen granule attenuates doxorubicin-induced cardiotoxicity by protecting mitochondrial function and reducing oxidative stress through regulation of Sirtuin3

ETHNOPHARMACOLOGICAL RELEVANCE

Doxorubicin (DOX) is one of the most potent chemotherapy drugs available today. However, the adverse effect of cardiotoxicity limits its clinical application. New approaches are being investigated for the treatment of doxorubicin-induced cardiotoxicity (DIC). Doxorubicin is enriched in mitochondria and it could induce imbalance of protein modification, including acetylation of mitochondria proteins, thereby inducing DIC. Restoration of mitochondria function is an effective way to attenuate DIC. The formula for traditional Chinese medicine Granules of Qishen (QSG) was derived from the classic formula "Zhen-Wu-Tang" which has been extensively used in the treatment of myocardial infarction. It consists of six traditional Chinese medicines, including Astragalus membranaceus var. mongholicus (Bunge) P.K.Hsiao (Fabaceae), Salvia miltiorrhiza Bunge (Lamiaceae), Lonicera japonica Thunb. (Caprifoliaceae), Aconitum carmichaelii Debeaux (Ranunculaceae), Scrophularia ningpoensis Hemsl. (Scrophulariaceae), and Glycyrrhiza uralensis Fisch. (Fabaceae). QSG is a potential anti-DIC formula. A better understanding of the effectiveness and pharmacological mechanisms of QSG will aid in the prevention and treatment of DIC.

AIM OF THE STUDY

The purpose of this research was to explore the effectiveness of QSG in the treatment of DIC and to explore whether QSG could protect mitochondrial function and reduce oxidative damage by activating Sirtuin3(SIRT3)/Acetylated-superoxide dismutase 2(Ac-SOD2) signaling pathway.

MATERIALS AND METHODS

DOX was injected into mice through the tail vein to construct a mouse model of DOX-induced cardiotoxicity to explore the therapeutic effect of QSG in animals. Meanwhile, the H9C2 cell model was used to study the mechanism of QSG. The cardiac function was evaluated by echocardiography, hematoxylin-eosin (H&E) staining and measurement of serum levels of creatine kinase isoenzymes (CK-MB) and lactate dehydrogenase (LDH). Oxidative damage was evaluated by 2',7'-dichlorodihydro fluorescein diacetate (DCFH-DA) staining and Mito-SOX Red staining. Levels of total superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were measured by following the instructions of commercially available kits. In order to detect the changes in mitochondrial membrane potential, cells were stained using the mitochondrial membrane potential detection kit (JC-1). Western blot analysis was applied to detect protein expressions of SIRT3, Ac-SOD2, Acetylation Lysine (Ac-Lys), Bax and Bcl-2. H9C2 cells were treated with SIRT3 inhibitor, in order to determine if QSG had effects via the SIRT3/Ac-SOD2 pathway.

RESULTS

In vivo studies showed that QSG ameliorated doxorubicin-induced damage of cardiac function in DIC mice model. The ejection fraction (EF) and fractional shortening (FS) were all up-regulated by QSG treatment. QSG decreased MDA levels and increased SOD activity. Meanwhile, doxorubicin induced high level of protein acetylation and QSG restored the acetylated protein back to normal levels. In particular, QSG upregulated expression of SIRT3 and downregulated Ac-SOD level. In vitro study demonstrated that QSG restored mitochondrial membrane potential, increased ATP level and reduced mitochondrial ROS production. When H9C2 cells were co-incubated with SIRT3 inhibitor, the efficacies of QSG on mitochondrial function were abrogated. Meanwhile, the regulative effects of QSG on SIRT3/Ac-SOD2 pathway were also abolished.

CONCLUSION

This study demonstrates that QSG is effective in treating DIC. QSG ameliorates oxidative damage and protects mitochondrial function partly by restoring protein acetylation level and by activating the SIRT3/Ac-SOD2 pathway.

SIRT3 ameliorates polycystic ovary syndrome through FOXO1/PGC-1α signaling pathway

BACKGROUND

Current studies have shown that Sirtuin3 (SIRT3) plays a key role in oocyte maturation. Polycystic ovary syndrome (PCOS) is a common disease caused by endocrine and metabolic abnormalities. The specific regulatory role and mechanism of SIRT3 in PCOS have not been reported.

METHODS

SIRT3 was overexpressed in dihydrotestosterone (DHT)-induced PCOS model in mice. Ovary morphology, serum hormone level, and apoptosis of tissue cells were detected. The expression of SIRT3/Forkhead box protein O1 (FOXO1)/peroxlsome proliferator-activated receptor-γ coactlvat-1α (PGC-1α)-related proteins was detected. Then SIRT3 was overexpressed in DHT-induced human granulosa-like tumor cell line KGN. After the detection of the pathway-associated proteins, PGC-1α specific inhibitor SR-18292 was added to detect cell apoptosis, mitochondrial membrane potential, mitochondrial ROS (MitoROS) levels, and other mitochondrial-related indicators RESULTS: The expression of SIRT3 in PCOS model was significantly decreased. Overexpression of SIRT3 could significantly improve ovarian morphology and serum sex hormone levels in DHT-induced PCOS mice and inhibit apoptosis both in vitro and in vivo. Overexpression of SIRT3 also could improve mitochondrial dysfunction in DHT-induced KGN cells via FOXO1/PGC-1α signaling pathway. And PGC-1α inhibitor SR-18292 reversed the protective effect of SIRT3 overexpression on apoptosis and mitochondrial function damage of DHT-induced KGN cells.

CONCLUSION

SIRT3 regulated FOXO1/PGC-1α signaling pathway to reduce mitochondrial dysfunction in PCOS, thereby improving PCOS.

SIRT3 improves alveolar epithelial cell damage caused by bronchopulmonary dysplasia through deacetylation of FOXO1

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a serious and long-term lung condition commonly observed in premature babies. Sirtuin 3 (SIRT3) has been reported to reduce pulmonary injury and pulmonary fibrosis.

OBJECTIVE

The present study investigated the specific role of SIRT3 in BPD by establishing hyperoxia-induced BPD rat and cell models. Hematoxylin and eosin staining was used to observe pathological changes in lung tissues.

MATERIALS AND METHODS

The expression levels of SIRT3 and forkhead box protein O1 (FOXO1), as well as its acetylation levels, were detected in hyperoxia-induced lung tissues and cells by Western blot analysis and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Levels of reactive oxygen species, superoxide dismutase, and malondialdehyde were assessed by using biochemical kits. Following SIRT3 overexpression, the levels of inflammatory cytokines were assessed by RT-qPCR. Apoptosis was determined by terminal deoxynucleotidyl transferase dUTP nickend labeling (TUNEL) and Western blot analysis. Upon FOXO1 knockout, cell inflammation, oxidative stress and apoptosis were evaluated again.

RESULTS

Compared to the control group, the SIRT3 and FOXO1 expression levels were decreased and the FOXO1 acetylation levels were increased in hyperoxia-induced lung tissues and cells. In addition, SIRT3 reduced hyperoxia-induced inflammation, oxidative stress, and apoptosis in A549 cells, and inhibited FOXO1 acetylation to activate FOXO1. However, FOXO1 knockdown reversed the effects of SIRT3 overexpression in hyperoxia-induced A549 cells.

CONCLUSION

SIRT3 relieved alveolar epithelial cell damage caused by BPD via deacetylation of FOXO1, suggesting that SIRT3 could be a therapeutic target in BPD.

Decreased Sirt3 contributes to cyclic production of reactive oxygen species and islet β-cell apoptosis in high glucose conditions

BACKGROUND

Reactive oxygen species (ROS) plays a vital role in the apoptosis of islet β-cells in type 2 diabetes mellitus (T2DM). Sirt3 (Sirtuin 3, a deacetylase) and FoxO1 (a transcription factor) might be involved in ROS production. This study was to investigate mechanism of ROS production and β-cell apoptosis in T2DM.

METHODS

Oxidative stress and apoptosis in islets of db/db mice and high glucose cultured β-cells were observed by terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay and western blotting. Then, H₂O₂ was used to ascertain the effect of ROS on the expression of Sirt3. Meanwhile, FoxO1, antioxidant enzymes - catalase (CAT) and manganese superoxide dismutase (MnSOD) and β-cell apoptosis were also determined by western blotting. Finally, Sirt3 was knocked down to evaluate the effect on oxidative stress and apoptosis of β-cells.

RESULTS

Under high glucose environment, enhanced ROS made a decrease of Sirt3 expression, which increased acetylation of FoxO1, thus reduced the expression of its target proteins -MnSOD and CAT, and further significantly increased ROS levels. Increased ROS finally led to the apoptosis of β-cells.

CONCLUSION

Down-regulation of Sirt3 plays an important role in the cyclic production of ROS and β-cell apoptosis. Targeting Sirt3 may be favorable for the treatment of T2DM.

Perspectives for Forkhead box transcription factors in diabetic cardiomyopathy: Their therapeutic potential and possible effects of salvianolic acids

Diabetic cardiomyopathy (DCM) is the primary cause of morbidity and mortality in diabetic cardiovascular complications, which initially manifests as cardiac hypertrophy, myocardial fibrosis, dysfunctional remodeling, and diastolic dysfunction, followed by systolic dysfunction, and eventually end with acute heart failure. Molecular mechanisms underlying these pathological changes in diabetic hearts are complicated and multifactorial, including but not limited to insulin resistance, oxidative stress, lipotoxicity, cardiomyocytes apoptosis or autophagy, inflammatory response, and myocardial metabolic dysfunction. With the development of molecular biology technology, accumulating evidence illustrates that members of the class O of Forkhead box (FoxO) transcription factors are vital for maintaining cardiomyocyte metabolism and cell survival, and the functions of the FoxO family proteins can be modulated by a wide variety of post-translational modifications including phosphorylation, acetylation, ubiquitination, arginine methylation, and O-glycosylation. In this review, we highlight and summarize the most recent advances in two members of the FoxO family (predominately FoxO1 and FoxO3a) that are abundantly expressed in cardiac tissue and whose levels of gene and protein expressions change as DCM progresses, with the goal of providing valuable insights into the pathogenesis of diabetic cardiovascular complications and discussing their therapeutic potential and possible effects of salvianolic acids, a natural product.

Phytochemicals targeting NAFLD through modulating the dual function of forkhead box O1 (FOXO1) transcription factor signaling pathways

Literature evidence reveals that natural compounds are potential candidates for ameliorating obesity-associated non-alcoholic fatty liver disease (NAFLD) by targeting forkhead box O1 (FOXO1) transcription factor. FOXO1 has a dual and complex role in regulating both increase and decrease in lipid accumulation in hepatocytes and adipose tissues (AT) at different stages of NAFLD. In insulin resistance (IR), it is constitutively expressed, resulting in increased hepatic glucose output and lipid metabolism irregularity. The studies on different phytochemicals indicate that dysregulation of FOXO1 causes disturbance in cellular nutrients homeostasis, and the natural entities have an enduring impact on the mitigation of these abnormalities. The current review communicates and evaluates certain phytochemicals through different search engines, targeting FOXO1 and its downstream cellular pathways to find lead compounds as potential therapeutic agents for treating NAFLD and related metabolic disorders. The findings of this review confirm that polyphenols, flavonoids, alkaloids, terpenoids, and anthocyanins are capable of modulating FOXO1 and associated signaling pathways, and they are potential therapeutic agents for NAFLD and related complications. HIGHLIGHTS: • FOXO1 has the potential to be targeted by novel drugs from natural sources for the treatment of NAFLD and obesity. • FOXO1 regulates cellular autophagy, inflammation, oxidative stress, and lipogenesis through alternative mechanisms. • Phytochemicals treat NAFLD by acting on FOXO1 or SREBP1c and PPARγ transcription factor signaling pathways.

Traditional Chinese medicine in the treatment of nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a common chronic liver disease in clinical practice. It has been considered that NASH is one of the main causes of chronic liver disease, cirrhosis and carcinoma. The mechanism of the NASH progression is complex, including lipid metabolism dysfunction, insulin resistance, oxidative stress, inflammation, apoptosis, fibrosis and gut microbiota dysbiosis. Except for lifestyle modification and bariatric surgery, there has been no pharmacological therapy that is being officially approved in NASH treatment. Traditional Chinese medicine (TCM), as a conventional and effective therapeutic strategy, has been proved to be beneficial in treating NASH in numbers of studies. In the light of this, TCM may provide a potential therapy for treating NASH. In this review, we summarized the associated mechanisms of action TCM treating NASH in preclinical studies and systematically analysis the effectiveness of TCM treating NASH in current clinical trials.

Effects of salvianolic acid B on glycometabolism and lipid metabolism in rodents: Meta-analysis

Danshen (Salvia miltiorrhiza) is a herb which has been widely used in China. Salvianolic acid B (SalB) is an aqueous bioactive component derived from Danshen. Here, we aimed to estimate the effect of SalB on glycometabolism and lipid metabolism in rats and mice. We searched four databases until November 2020. The outcome measures were fasting blood glucose (FBG), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDLc), and low-density lipoprotein cholesterol (LDLc). Twenty-four studies involving 547 animals were included. The meta-analysis showed effects of SalB on decreasing the level of FBG, TC, TG, LDLc, and increasing the level of HDLc compared with the control group. In conclusion, the result showed that SalB may regulate the glycometabolism and lipid metabolism in rats or mice, and may be a potential agent for treating metabolic diseases such as diabetes and hyperlipidemia.

Salvianolic acid B protects against MPP+-induced neuronal injury via repressing oxidative stress and restoring mitochondrial function

Maintaining normal conditions in the mitochondria and repressing oxidative stress has emerged as a crucial therapeutic strategy to ameliorate neuron damage in Parkinson's disease. Salvianolic acid B (SalB) is a polyphenolic compound isolated from Salvia miltiorrhiza, which has been prescribed for various biological properties, including antioxidative stress, anti-inflammation and neuroprotection in pathological conditions. Previously, SalB was reported to be of benefit in slowing Parkinson's disease pathology, but whether the neuroprotective role of SalB is associated with a mitochondrial protective action is still elusive. Here we aimed to explore the effects of SalB on mitochondrial function in Parkinson's disease to uncover the underlying cellular mechanisms. The results showed that SalB significantly alleviated 1-methyl-4-phenylpyridinium (MPP+)-induced mitochondrial disruption in line with ameliorated oxidative injury, which is evidenced by inhibited mitochondrial membrane potential collapse, reduced reactive oxygen species (ROS) generation, increased expression of NAD(P)H: quinone oxidoreductase, and enhanced mitochondrial biosynthesis - the upregulation of nuclear respiratory factor 1 and mitochondrial transcription factor A expressions. Mechanistically, SalB not only increased AMP-activated protein kinase (AMPK) activation and sirtuin3 mRNA and protein levels, but also attenuated ROS-triggered neuroinflammation by downregulating the expressions of NOD-like receptor family pyrin domain containing 3, caspase-1 and Interleukin-1β (IL-1β). In conclusion, these in-vitro findings, for the first time, demonstrate that SalB offers protection against MPP+-induced neuronal injury via upregulating sirtuin3 expression and activating the AMPK signaling to restore mitochondrial function.

Sirtuins-Mediated System-Level Regulation of Mammalian Tissues at the Interface between Metabolism and Cell Cycle: A Systematic Review

Sirtuins are a family of highly conserved NAD+-dependent proteins and this dependency links Sirtuins directly to metabolism. Sirtuins' activity has been shown to extend the lifespan of several organisms and mainly through the post-translational modification of their many target proteins, with deacetylation being the most common modification. The seven mammalian Sirtuins, SIRT1 through SIRT7, have been implicated in regulating physiological responses to metabolism and stress by acting as nutrient sensors, linking environmental and nutrient signals to mammalian metabolic homeostasis. Furthermore, mammalian Sirtuins have been implicated in playing major roles in mammalian pathophysiological conditions such as inflammation, obesity and cancer. Mammalian Sirtuins are expressed heterogeneously among different organs and tissues, and the same holds true for their substrates. Thus, the function of mammalian Sirtuins together with their substrates is expected to vary among tissues. Any therapy depending on Sirtuins could therefore have different local as well as systemic effects. Here, an introduction to processes relevant for the actions of Sirtuins, such as metabolism and cell cycle, will be followed by reasoning on the system-level function of Sirtuins and their substrates in different mammalian tissues. Their involvement in the healthy metabolism and metabolic disorders will be reviewed and critically discussed.

Research progress in use of traditional Chinese medicine monomer for treatment of non-alcoholic fatty liver disease

With the improvement of people's living standards and the change of eating habits, non-alcoholic fatty liver disease (NAFLD) has gradually become one of the most common chronic liver diseases in the world. However, there are no effective drugs for the treatment of NAFLD. Therefore, it is urgent to find safe, efficient, and economical anti-NAFLD drugs. Compared with western medicines that possess fast lipid-lowering effect, traditional Chinese medicines (TCM) have attracted increasing attention for the treatment of NAFLD due to their unique advantages such as multi-targets and multi-channel mechanisms of action. TCM monomers have been proved to treat NAFLD through regulating various pathways, including inflammation, lipid production, insulin sensitivity, mitochondrial dysfunction, autophagy, and intestinal microbiota. In particular, peroxisome proliferator-activated receptor α (PPAR-α), sterol regulatory element-binding protein 1c (SREBP-1c), nuclear transcription factor kappa (NF-κB), phosphoinositide 3-kinase (PI3K), sirtuin1 (SIRT1), AMP-activated protein kinase (AMPK), p53 and nuclear factor erythroid 2-related factor 2 (Nrf2) are considered as important molecular targets for ameliorating NAFLD by TCM monomers. Therefore, by searching PubMed, Web of Science and SciFinder databases, this paper updates and summarizes the experimental and clinical evidence of TCM monomers for the treatment of NAFLD in the past six years (2015-2020), thus providing thoughts and prospects for further exploring the pathogenesis of NAFLD and TCM monomer therapies.

Emerging targets and potential therapeutic agents in non-alcoholic fatty liver disease treatment

Nonalcoholic Fatty Liver Disease (NAFLD) is the most common chronic liver disease in the world, which is characterized by liver fat accumulation unrelated to excessive drinking. Indeed, it attracts growing attention and becomes a global health problem. Due to the complexity of the NAFLD pathogenic mechanism, no related drugs were approved by Food and Drug Administration (FDA) till now. However, it is encouraging that a series of candidate drugs have entered the clinical trial stage with expectation to treat NAFLD. In this review, we summarized the main pathways and pathogenic mechanisms of NAFLD, as well as introduced the main potential therapeutic targets and the corresponding compounds involved in metabolism, inflammation and fibrosis. Furthermore, we also discuss the progress of these compounds, such as drug design and optimization, the choice of pharmacological properties and druglikeness, and the analysis of structure-activity relationship. This review offers a medium on future drug design and development, to be beneficial to relevant studies.

Intestinal Trefoil Factor 3 Alleviates the Intestinal Barrier Function Through Reducing the Expression of TLR4 in Rats with Nonalcoholic Steatohepatitis

BACKGROUND

Previous studies have reported that nonalcoholic steatohepatitis (NASH) is relevant to intestinal mucosal barrier dysfunction.

AIM OF THE STUDY

To investigate the effects of intestinal trefoil factor 3 (TFF3) on intestinal barrier function and endotoxin/toll-like receptor 4(TLR4) expression in NASH rats.

METHODS

Sixty NASH rats were divided into control, NASH and NASH-TFF3 treated group. Intestinal permeability, serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), endotoxin (ET), diamine oxidase (DAO) and liver index were examined. HE and PAS staining were performed to observe the histopathology of liver and terminal ileum. Expression of TFF3 and occludin were detected by immunohistochemical staining. mRNA and protein expression of TLR4, nuclear factor-κB (NF-κB), Mucin-2(Muc2) were detected by RT-qPCR and Western Blot. Interleukin (IL) -1β and IL-10 levels in the ileum were measured by ELISA.

RESULTS

In NASH group, levels of AST, ALT, ET, DAO, NAS, liver index and intestinal permeability were higher while occludin expressions were lower than control and NASH-TFF3 treated groups (p <0.05). Histopathology examination showed pathological damages of liver and ileum were alleviated in NASH-TFF3 treated group. NASH-TFF3 treated group had decreased expression levels of TLR4 and NF-κB and increased expression levels of Muc2 than NASH group. Besides, NASH group showed increased IL-1β and IL-10 levels compared with control group. NASH-TFF3 treated group showed decreased IL-1β level however increased IL-10 level compared with NASH group.

CONCLUSION

Recombinant human TFF3 (rhTFF3) can reduce the expression of TLR4, reduce intestinal permeability, alleviate liver damage and thus may play a therapeutic role in the treatment of NASH rats.

Effects and mechanisms of Danshen-Shanzha herb-pair for atherosclerosis treatment using network pharmacology and experimental pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

The danshen (the root of Salvia miltiorrhiza Bge.)-shanzha (the fruit of Crataegus pinnatifida Bge. var. major N.E.Br.) (DS) herb combination is a commonly used traditional Chinese medicine with cardiovascular disease (CVD) treatment potential.

MATERIALS AND METHODS

In this study, we investigated the anti-atherosclerotic effects and mechanisms of DS by the integration of network pharmacology and polypharmacology. Eight main components were selected for target fishing by PharmMapper.

RESULTS

The network pharmacological study indicated that DS may target 41 proteins and 16 pathways associated with inflammation, lipid metabolism and endothelial protection, which indicates that DS probably adjusts these processes as part of its anti-atherosclerotic activities. Furthermore, this hypothesis was verified by polypharmacology using an atherosclerotic model. Histopathological examination showed that DS inhibited pathological changes in the arteries of atherosclerotic rats and reduced the intima-media thickness (IMT). DS significantly reduced the levels of total cholesterol (TC), triglyceride (TG), and low-density lipoprotein-cholesterol (LDL-C) and increased the high-density lipoprotein-cholesterol (HDL-C) level in the blood. DS also decreased the concentrations of interleukin (IL)-1β and IL-18, indicating anti-inflammation activity. In addition, DS increased the serum levels of nitric oxide (NO) and 6-keto-prostaglandin F_1α (6-keto-PGF_1α) and decreased the serum levels of endothelin (ET) and thromboxane B₂ (TXB₂), indicating an endothelial protective effect.

CONCLUSIONS

In conclusion, DS has an anti-atherosclerotic ability to lower lipid concentrations and to protect endothelial function, and it also has anti-inflammatory activity.