Role of SIRT1 in regulation of LPS- or two ethanol metabolites-induced TNF-alpha production in cultured macrophage cell lines

Wogonin alleviates sepsis-induced acute lung injury by modulating macrophage polarization through the SIRT1-FOXO1 pathways

Sepsis-induced acute lung injury is a common and severe complication of sepsis, for which effective treatments are currently lacking. Previous studies have demonstrated the influence of wogonin in treating acute lung injury (ALI). However, its precise mechanism of action remains unclear. To delve deeper into the mechanisms underlying wogonin's impacts in sepsis-induced acute lung injury, we established a mouse sepsis model through cecal ligation and puncture and conducted further cell experiments using lipopolysaccharide-treated MH-S and MLE-12 cells to explore wogonin's potential mechanisms of action in treating ALI. Our results revealed that wogonin significantly increased the survival rate of mice, alleviated pulmonary pathological damage and inflammatory cell infiltration, and activated the SIRT1-FOXO1 pathway. Additionally, wogonin suppressed the release of pro-inflammatory factors by M1 macrophages and induced the activation of M2 anti-inflammatory factors. Further in vitro studies confirmed that wogonin effectively inhibited M1 macrophage polarization through the activation of the SIRT1-FOXO1 pathway, thereby mitigating lung pathological changes caused by ALI. In summary, our study demonstrated that wogonin regulated macrophage M1/M2 polarization through the activation of the SIRT1-FOXO1 pathway, thereby attenuating the inflammatory response and improving pulmonary pathological changes induced by sepsis-induced ALI. This discovery provided a solid mechanistic foundation for the therapeutic use of wogonin in sepsis-induced ALI, shedding new light on potential strategies for the treatment of sepsis-induced ALI.

Research Progress on Anti-Inflammatory Effects and Related Mechanisms of Astragalin

Chronic inflammation is a significant contributor to the development of cancer, cardiovascular disease, diabetes, obesity, autoimmune disease, inflammatory bowel disease, and other illnesses. In the academic field, there is a constant demand for effective methods to alleviate inflammation. Astragalin (AST), a type of flavonoid glycoside that is the primary component in several widely used traditional Chinese anti-inflammatory medications in clinical practice, has garnered attention from numerous experts and scholars. This article focuses on the anti-inflammatory effects of AST and conducts research on relevant literature from 2003 to 2023. The findings indicate that AST demonstrates promising anti-inflammatory potential in various models of inflammatory diseases. Specifically, AST is believed to possess inhibitory effects on inflammation-related factors and protein levels in various in vitro cell models, such as macrophages, microglia, and epithelial cells. In vivo studies have shown that AST effectively alleviates neuroinflammation and brain damage while also exhibiting potential for treating moderate diseases such as depression and stroke; it also demonstrates significant anti-inflammatory effects on both large and small intestinal epithelial cells. Animal experiments have further demonstrated that AST exerts therapeutic effects on colitis mice. Molecular biology studies have revealed that AST regulates complex signaling networks, including NF-κB, MAPK, JAK/STAT pathways, etc. In conclusion, this review will provide insights and references for the development of AST as an anti-inflammatory agent as well as for related drug development.

Dihydromyricetin supplementation improves ethanol-induced lipid accumulation and inflammation

Introduction

Excessive alcohol consumption leads to a myriad of detrimental health effects, including alcohol-associated liver disease (ALD). Unfortunately, no available treatments exist to combat the progression of ALD beyond corticosteroid administration and/or liver transplants. Dihydromyricetin (DHM) is a bioactive polyphenol and flavonoid that has traditionally been used in Chinese herbal medicine for its robust antioxidant and anti-inflammatory properties. It is derived from many plants, including Hovenia dulcis and is found as the active ingredient in a variety of popular hangover remedies. Investigations utilizing DHM have demonstrated its ability to alleviate ethanol-induced disruptions in mitochondrial and lipid metabolism, while demonstrating hepatoprotective activity.

Methods

Female c57BL/6J mice (n = 12/group) were treated using the Lieber DeCarli forced-drinking and ethanol (EtOH) containing liquid diet, for 5 weeks. Mice were randomly divided into three groups: (1) No-EtOH, (2) EtOH [5% (v/v)], and (3) EtOH [5% (v/v)] + DHM (6 mg/mL). Mice were exposed to ethanol for 2 weeks to ensure the development of ALD pathology prior to receiving dihydromyricetin supplementation. Statistical analysis included one-way ANOVA along with Bonferroni multiple comparison tests, where p ≤ 0.05 was considered statistically significant.

Results

Dihydromyricetin administration significantly improved aminotransferase levels (AST/ALT) and reduced levels of circulating lipids including LDL/VLDL, total cholesterol (free cholesterol), and triglycerides. DHM demonstrated enhanced lipid clearance by way of increased lipophagy activity, shown as the increased interaction and colocalization of p62/SQSTM-1, LC3B, and PLIN-1 proteins. DHM-fed mice had increased hepatocyte-to-hepatocyte lipid droplet (LD) heterogeneity, suggesting increased neutralization and sequestration of free lipids into LDs. DHM administration significantly reduced prominent pro-inflammatory cytokines commonly associated with ALD pathology such as TNF-α, IL-6, and IL-17.

Discussion

Dihydromyricetin is commercially available as a dietary supplement. The results of this proof-of-concept study demonstrate its potential utility and functionality as a cost-effective and safe candidate to combat inflammation and the progression of ALD pathology.

Harnessing the potential of probiotics in the treatment of alcoholic liver disorders

In the current scenario, prolonged consumption of alcohol across the globe is upsurging an appreciable number of patients with the risk of alcohol-associated liver diseases. According to the recent report, the gut-liver axis is crucial in the progression of alcohol-induced liver diseases, including steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Despite several factors associated with alcoholic liver diseases, the complexity of the gut microflora and its great interaction with the liver have become a fascinating area for researchers due to the high exposure of the liver to free radicals, bacterial endotoxins, lipopolysaccharides, inflammatory markers, etc. Undoubtedly, alcohol-induced gut microbiota imbalance stimulates dysbiosis, disrupts the intestinal barrier function, and trigger immune as well as inflammatory responses which further aggravate hepatic injury. Since currently available drugs to mitigate liver disorders have significant side effects, hence, probiotics have been widely researched to alleviate alcohol-associated liver diseases and to improve liver health. A broad range of probiotic bacteria like Lactobacillus, Bifidobacteria, Escherichia coli, Sacchromyces, and Lactococcus are used to reduce or halt the progression of alcohol-associated liver diseases. Several underlying mechanisms, including alteration of the gut microbiome, modulation of intestinal barrier function and immune response, reduction in the level of endotoxins, and bacterial translocation, have been implicated through which probiotics can effectively suppress the occurrence of alcohol-induced liver disorders. This review addresses the therapeutic applications of probiotics in the treatment of alcohol-associated liver diseases. Novel insights into the mechanisms by which probiotics prevent alcohol-associated liver diseases have also been elaborated.

Potentials of curcumin against polycystic ovary syndrome: Pharmacological insights and therapeutic promises

Polycystic ovary syndrome (PCOS) is a common hormonal disorder among women (4%-20%) when the ovaries create abnormally high levels of androgens, the male sex hormones that are typically present in women in trace amounts. The primary characteristics of PCOS include oxidative stress, inflammation, hyperglycemia, hyperlipidemia, hyperandrogenism, and insulin resistance. Generally, metformin, spironolactone, eflornithine and oral contraceptives are used to treat PCOS, despite their several side effects. Therefore, finding a potential candidate for treating PCOS is necessary. Curcumin is a major active natural polyphenolic compound derived from turmeric (Curcuma longa). A substantial number of studies have shown that curcumin has anti-inflammatory, anti-oxidative stress, antibacterial, and anti-apoptotic activities. In addition, curcumin reduces hyperglycemia, hyperlipidemia, hyperandrogenism, and insulin resistance in various conditions, including PCOS. The review highlighted the therapeutic aspects of curcumin against the pathophysiology of PCOS. We also offer a hypothesis to improve the development of medicines based on curcumin against PCOS.

The deacetylation of Akt by SIRT1 inhibits inflammation in macrophages and protects against sepsis

Sepsis is characterized by uncontrolled inflammatory response and altered polarization of macrophages at the early phase. Akt is known to drive macrophage inflammatory response. However, how macrophage inflammatory response is fine-tuned by Akt is poorly understood. Here, we found that Lys14 and Lys20 of Akt is deacetylated by the histone deacetylase SIRT1 during macrophage activation to suppress macrophages inflammatory response. Mechanistically, SIRT1 promotes Akt deacetylation to inhibit the activation of NF-κB and pro-inflammatory cytokines. Loss of SIRT1 facilitates Akt acetylation and thus promotes inflammatory cytokines in mouse macrophages, potentially worsen the progression of sepsis in mice. By contrast, the upregulation of SIRT1 in macrophages further contributes to the inhibition of pro-inflammatory cytokines via Akt activation in sepsis. Taken together, our findings establish Akt deacetylation as an essential negative regulatory mechanism that curtails M1 polarization.

Combined carvacrol and cilostazol ameliorate ethanol-induced liver fibrosis in rats: Possible role of SIRT1/Nrf2/HO-1 pathway

Carvacrol is a natural phenolic monoterpenoid, and cilostazol is a selective phosphodiesterase-3 inhibitor with antioxidant, anti-inflammatory and antiapoptotic effects. This experiment aimed to explore the hepatoprotective effects of carvacrol and cilostazol alone and in combination against alcoholic liver fibrosis (ALF), and the underlying mechanisms, using silymarin as a reference anti-fibrotic product. ALF was induced by oral administration of ethanol (1 ml/100 g/day) thrice per week. Silymarin (100 mg/kg), carvacrol (70 mg/kg), cilostazol (50 mg/kg), or carvacrol + cilostazol combination were administered daily and concurrently with ethanol for six weeks. Hepatic changes were evaluated by quantifying serum biomarkers of liver injury, hepatic MDA, GSH and NOx as oxidative stress markers, interleukin (IL)-10 as an anti-inflammatory cytokine, 4-hydroxyproline (4-HYP) as a collagen synthesis indicator, transforming growth factor (TGF)-β1 as a profibrogenic cytokine, α-smooth muscle actin (α-SMA) as a marker of hepatic stellate cells (HSCs) activation, histopathological (necroinflammation and fibrosis) scores and hepatic sirtuin-1 (SIRT1), nuclear factor-erythroid 2-related factor 2 (Nrf2), and hemeoxygenase-1 (HO-1) mRNA levels. Our results showed that carvacrol, cilostazol, and their combination significantly ameliorated ethanol-induced hepatic fibrosis manifested as improving hepatic functions and histopathological features, attenuating α-SMA immunostaining, reducing TGF-β1 and 4-HYP levels, suppressing oxidativeinjury and elevating IL-10 contents. Such effects were accompanied by upregulating SIRT1, Nrf2 and HO-1 genes. This work disclosed for the first time the hepatoprotective effect of carvacrol against ALF and, to a greater extent, with carvacrol + cilostazol combination that could be partially accredited to SIRT1/Nrf2/HO-1 pathway with consequent antioxidant, anti-inflammatory, and anti-fibrotic features.

Bioactive Compounds as Inhibitors of Inflammation, Oxidative Stress and Metabolic Dysfunctions via Regulation of Cellular Redox Balance and Histone Acetylation State

Bioactive compounds (BCs) are known to exhibit antioxidant, anti-inflammatory, and anti-cancer properties by regulating the cellular redox balance and histone acetylation state. BCs can control chronic oxidative states caused by dietary stress, i.e., alcohol, high-fat, or high-glycemic diet, and adjust the redox balance to recover physiological conditions. Unique functions of BCs to scavenge reactive oxygen species (ROS) can resolve the redox imbalance due to the excessive generation of ROS. The ability of BCs to regulate the histone acetylation state contributes to the activation of transcription factors involved in immunity and metabolism against dietary stress. The protective properties of BCs are mainly ascribed to the roles of sirtuin 1 (SIRT1) and nuclear factor erythroid 2-related factor 2 (NRF2). As a histone deacetylase (HDAC), SIRT1 modulates the cellular redox balance and histone acetylation state by mediating ROS generation, regulating nicotinamide adenine dinucleotide (NAD+)/NADH ratio, and activating NRF2 in metabolic progression. In this study, the unique functions of BCs against diet-induced inflammation, oxidative stress, and metabolic dysfunction have been considered by focusing on the cellular redox balance and histone acetylation state. This work may provide evidence for the development of effective therapeutic agents from BCs.

The Patatin-Like Phospholipase Domain Containing Protein 7 Regulates Macrophage Classical Activation through SIRT1/NF-κB and p38 MAPK Pathways

Lysophosphatidylcholine (LPC) is a bioactive lipid that modulates macrophage polarization during immune responses, inflammation, and tissue remodeling. Patatin-like phospholipase domain containing protein 7 (PNPLA7) is a lysophospholipase with a preference for LPC. However, the role of PNPLA7 in macrophage polarization as an LPC hydrolase has not been explored. In the current study, we found that PNPLA7 is highly expressed in naïve macrophages and downregulated upon lipopolysaccharide (LPS)-induced polarization towards the classically activated (M1) phenotype. Consistently, overexpression of PNPLA7 suppressed the expression of proinflammatory M1 marker genes, including interleukin 1β (IL-1β), IL-6, inducible nitric oxide synthase (iNOS), and tumor necrosis factor α (TNF-α), whereas knockdown of PNPLA7 augmented the inflammatory gene expression in LPS-challenged macrophages. PNPLA7 overexpression and knockdown increased and decreased Sirtuin1 (SIRT1) mRNA and protein levels, respectively, and affected the acetylation of the nuclear factor-kappa B (NF-κB) p65 subunit, a key transcription factor in M1 polarization. In addition, the levels of phosphorylated p38 mitogen-activated protein kinase (MAPK) were suppressed and enhanced by PNPLA7 overexpression and knockdown, respectively. Taken together, these findings suggest that PNPLA7 suppresses M1 polarization of LPS-challenged macrophages by modulating SIRT1/NF-κB- and p38 MAPK-dependent pathways.

The Effects of Probiotics, Prebiotics and Synbiotics in Non-Alcoholic Fat Liver Disease (NAFLD) and Non-Alcoholic Steatohepatitis (NASH): A Systematic Review

Modifications in the microbiota caused by environmental and genetic reasons can unbalance the intestinal homeostasis, deregulating the host’s metabolism and immune system, intensifying the risk factors for the development and aggravation of non-alcoholic fat liver disease (NAFLD). The use of probiotics, prebiotics and synbiotics have been considered a potential and promising strategy to regulate the gut microbiota and produce beneficial effects in patients with liver conditions. For this reason, this review aimed to evaluate the effectiveness of probiotics, prebiotics, and symbiotics in patients with NAFLD and NASH. Pubmed, Embase, and Cochrane databases were consulted, and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines were followed. The clinical trials used in this study demonstrated that gut microbiota interventions could improve a wide range of markers of inflammation, glycemia, insulin resistance, dyslipidemia, obesity, liver injury (decrease of hepatic enzymes and steatosis and fibrosis). Although microbiota modulators do not play a healing role, they can work as an important adjunct therapy in pathological processes involving NAFLD and its spectrums, either by improving the intestinal barrier or by preventing the formation of toxic metabolites for the liver or by acting on the immune system.

Microbiome-Based Metabolic Therapeutic Approaches in Alcoholic Liver Disease

Alcohol consumption is a global healthcare problem. Chronic alcohol consumption generates a wide spectrum of hepatic lesions, the most characteristic of which are steatosis, hepatitis, fibrosis, and cirrhosis. Alcoholic liver diseases (ALD) refer to liver damage and metabolomic changes caused by excessive alcohol intake. ALD present several clinical stages of severity found in liver metabolisms. With increased alcohol consumption, the gut microbiome promotes a leaky gut, metabolic dysfunction, oxidative stress, liver inflammation, and hepatocellular injury. Much attention has focused on ALD, such as alcoholic fatty liver (AFL), alcoholic steatohepatitis (ASH), alcoholic cirrhosis (AC), hepatocellular carcinoma (HCC), a partnership that reflects the metabolomic significance. Here, we report on the global function of inflammation, inhibition, oxidative stress, and reactive oxygen species (ROS) mechanisms in the liver biology framework. In this tutorial review, we hypothetically revisit therapeutic gut microbiota-derived alcoholic oxidative stress, liver inflammation, inflammatory cytokines, and metabolic regulation. We summarize the perspective of microbial therapy of genes, gut microbes, and metabolic role in ALD. The end stage is liver transplantation or death. This review may inspire a summary of the gut microbial genes, critical inflammatory molecules, oxidative stress, and metabolic routes, which will offer future promising therapeutic compounds in ALD.

Amelioration of Renal Injury by Resveratrol in a Rat Renal Transplantation Model via Activation of the SIRT1/NF-κB Signaling Pathway

Purpose. The improvement of the long-term survival of patients receiving kidney transplantation remains challenging. Ischemia reperfusion injury (IRI) reduces long-term renal graft survival in the early posttransplantation phase. However, few studies have investigated the effects of IRI on the pathogenesis of chronic renal graft failure. Silent information regulator 1 (SIRT1) regulates antioxidative stress and inflammatory response and protects against IRI. This study is aimed at investigating the role of resveratrol (RSV), an SIRT1 activator, in preventing renal injury in a rat renal transplantation model. Methods. A classical F334-to-LEW orthotopic renal transplantation rat model was established. The experiment group was treated with RSV from three days prior to kidney transplantation and the treatment lasted until the day of harvest. Uninephrectomized F344 and Lewis rats were used as controls. After 12 weeks, the effects of RSV were evaluated according to renal function, histopathology, immunohistochemistry, and western blotting. The activities of oxidative stress-related markers and proinflammatory cytokines were also assessed. Results. RSV treatment significantly ameliorated renal function and histopathological lesions in kidney-transplanted rats and increased the levels of GSH, SOD, and CAT and decreased the levels of MDA and iNOS. Furthermore, RSV also inhibited the expression of proinflammatory cytokines/chemokines such as TNF-α, CD68, and IL-6 in kidney-transplanted rats. In addition, the transplant group displayed significantly lower level of SIRT1 and higher level of Ac-NF-κBp65. RSV increased the expression of SIRT1 and decreased the expression of Ac-NF-κBp65. Conclusion. SIRT1 plays an important role in the pathogenesis of chronic renal allograft dysfunction. It is a potential therapeutic agent for ameliorating inflammation and oxidative stress-induced renal injury following kidney transplantation by activating the SIRT1/NF-κB signaling pathway.

Epigenetics of alcohol-related liver diseases

Alcohol-related liver disease (ARLD) is a primary cause of chronic liver disease in the United States. Despite advances in the diagnosis and management of ARLD, it remains a major public health problem associated with significant morbidity and mortality, emphasising the need to adopt novel approaches to the study of ARLD and its complications. Epigenetic changes are increasingly being recognised as contributing to the pathogenesis of multiple disease states. Harnessing the power of innovative technologies for the study of epigenetics (e.g., next-generation sequencing, DNA methylation assays, histone modification profiling and computational techniques like machine learning) has resulted in a seismic shift in our understanding of the pathophysiology of ARLD. Knowledge of these techniques and advances is of paramount importance for the practicing hepatologist and researchers alike. Accordingly, in this review article we will summarise the current knowledge about alcohol-induced epigenetic alterations in the context of ARLD, including but not limited to, DNA hyper/hypo methylation, histone modifications, changes in non-coding RNA, 3D chromatin architecture and enhancer-promoter interactions. Additionally, we will discuss the state-of-the-art techniques used in the study of ARLD (e.g. single-cell sequencing). We will also highlight the epigenetic regulation of chemokines and their proinflammatory role in the context of ARLD. Lastly, we will examine the clinical applications of epigenetics in the diagnosis and management of ARLD.

Structure-toxicity relationships, toxicity mechanisms and health risk assessment of food-borne modified deoxynivalenol and zearalenone: A comprehensive review

Mycotoxin, as one of the most common pollutants in foodstuffs, poses great threat to food security and human health. Specifically, deoxynivalenol (DON) and zearalenone (ZEN)-two mycotoxin contaminants with considerable toxicity widely existing in food products-have aroused broad public concerns. Adding to this picture, modified forms of DON and ZEN, have emerged as another potential environmental and health threat, owing to their higher re-transformation rate into parent mycotoxins inducing accumulation of mycotoxin in humans and animals. Given this, a better understanding of the toxicity of modified mycotoxins is urgently needed. Moreover, the lack of toxicity data means a proper risk assessment of modified mycotoxins remains challenging. To better evaluate the toxicity of modified DON and ZEN, we have reviewed the relationship between their structures and toxicities. The toxicity mechanisms behind modified DON and ZEN have also been discussed; briefly, these involve acute, subacute, chronic, and combined toxicities. In addition, this review also addresses the global occurrence of modified DON and ZEN, and summarizes novel methods-including in silico analysis and implementation of relative potency factors-for risk assessment of modified DON and ZEN. Finally, the health risk assessment of modified DON and ZEN has also been discussed comprehensively.

Transcriptional and Epigenetic Regulation of Monocyte and Macrophage Dysfunction by Chronic Alcohol Consumption

Drinking alcohol, even in moderation, can affect the immune system. Studies have shown disproportionate effects of alcohol on circulating and tissue-resident myeloid cells (granulocytes, monocytes, macrophages, dendritic cells). These cells orchestrate the body's first line of defense against microbial challenges as well as maintain tissue homeostasis and repair. Alcohol's effects on these cells are dependent on exposure pattern, with acute drinking dampening but chronic drinking enhancing production of inflammatory mediators. Although chronic drinking is associated with heightened systemic inflammation, studies on tissue resident macrophage populations in several organs including the spleen, liver, brain, and lung have also shown compromised functional and metabolic capacities of these cells. Many of these effects are thought to be mediated by oxidative stress caused by alcohol and its metabolites which can directly impact the cellular epigenetic landscapes. In addition, since myeloid cells are relatively short-lived in circulation and are under constant repopulation from the bone marrow compartment, alcohol's effects on bone marrow progenitors and hematopoiesis are important for understanding the impact of alcohol systemically on these myeloid populations. Alcohol-induced disruption of progenitor, circulating, and tissue resident myeloid populations contribute to the increased susceptibility of patients with alcohol use disorders to viral and bacterial infections. In this review, we provide an overview of the impact of chronic alcohol consumption on the function of monocytes and macrophages in host defense, tissue repair and inflammation. We then summarize our current understanding of the mechanisms underlying alcohol-induced disruption and examine changes in transcriptome and epigenome of monocytes and mcrophages. Overall, chronic alcohol consumption leads to hyper-inflammation concomitant with decreased microbial and wound healing responses by monocytes/macrophages due to a rewiring of the epigentic and transcriptional landscape. However, in advanced alcoholic liver disease, myeloid cells become immunosuppressed as a response to the surrounding hyper-inflammatory milieu. Therefore, the effect of chronic alcohol on the inflammatory response depends on disease state and the immune cell population.

Deletion of intestinal SIRT1 exacerbated muscle wasting in cirrhotic mice by decreasing the intestinal concentration of short-chain fatty acids and inflammation

Systemic sirtuin 1 (SIRT1) activation alleviates muscle wasting and improves muscle function by downregulation of myotropic and proteolytic markers. In this study, we evaluated the effects of the intestinal Sirt1 deletion on the dysregulated gutmuscle axis in cirrhotic mice. Cirrhosis-related muscle wasting was induced by common bile duct ligated (BDL) in either wild-type (WT) or intestine-specific Sirt1-deleted (Sirt1IEC-KO) mice, including WT-BDL, WT-sham, Sirt1IEC-KO-BDL and Sirt1IEC-KO-sham mice. Compared with WT-BDL mice, Sirt1IEC-KO-BDL mice showed worsened low lean mass, exacerbated muscle wasting, increased expression of myotropic markers, increased muscular protein degradation, and decreased expression of myogenic markers through aggravation of intestinal inflammation (as evidenced by increased fecal calprotectin/lipocalin-2 levels, increased intestinal macrophage infiltration, and increased intestinal TNFα/IL-6 levels), decrease in abundance of short-chain fatty acid (SCFA)-producing bacteria, decrease in levels of intestinal SCFAs (with anti-inflammatory effects), and downregulation of SCFA receptor GPR43. In biliary cirrhotic mice, a decrease in the abundance of SCFA-producing bacteria and an increase in the levels of intestinal/muscular inflammatory markers are involved in the pathogenesis of dysregulated gut-muscle axis-related muscle wasting, and intestinal deletion of Sirt1 exacerbated these changes.

Therapeutic Role of Sirtuins Targeting Unfolded Protein Response, Coagulation, and Inflammation in Hypoxia-Induced Thrombosis

Thrombosis remains one of the leading causes of morbidity and mortality across the world. Many pathological milieus in the body resulting from multiple risk factors escort thrombosis. Hypoxic condition is one such risk factor that disturbs the integrity of endothelial cells to cause an imbalance between anticoagulant and procoagulant proteins. Hypoxia generates reactive oxygen species (ROS) and triggers inflammatory pathways to augment the coagulation cascade. Hypoxia in cells also activates unfolded protein response (UPR) signaling pathways in the endoplasmic reticulum (ER), which tries to restore ER homeostasis and function. But the sustained UPR linked with inflammation, generation of ROS and apoptosis stimulates the severity of thrombosis in the body. Sirtuins, a group of seven proteins, play a vast role in bringing down inflammation, oxidative and ER stress and apoptosis. As a result, sirtuins might provide a therapeutic approach towards the treatment or prevention of hypoxia-induced thrombosis. Sirtuins modulate hypoxia-inducible factors (HIFs) and counteract ER stress-induced apoptosis by attenuating protein kinase RNA-like endoplasmic reticulum kinase (PERK)/Eukaryotic translation initiation factor 2α (eIF2α) pathway activation. It prevents ER-stress mediated inflammation by targeting X-Box Binding Protein 1 (XBP1) and inhibiting nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κβ) signaling through deacetylation. Sirtuins also obstruct nucleotide-binding domain, leucine-rich-containing family, pyrin domain containing 3 (NLRP3) inflammasome activation to reduce the expression of several pro-inflammatory molecules. It protects cells against oxidative stress by targeting nuclear factor erythroid 2-related factor 2 (Nrf2), glutathione (GSH), forkhead box O3 (FOXO3), superoxide dismutase (SOD), catalase (CAT), peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α), glucose-6-phosphate dehydrogenase (G6PD), phosphoglucomutase-2 (PGAM2), and NF-κB, to name few. This review, thus, discusses the potential role of sirtuins as a new treatment for hypoxia-induced thrombosis that involves an intersection of UPR and inflammatory pathways in its pathological manifestation.

Functional delivery of lncRNA TUG1 by endothelial progenitor cells derived extracellular vesicles confers anti-inflammatory macrophage polarization in sepsis via impairing miR-9-5p-targeted SIRT1 inhibition

The delivery of biomolecules by extracellular vesicles (EVs) derived from endothelial progenitor cells (EPCs) has been proven to ameliorate sepsis, yet the therapeutic mechanism remains to be elucidated. Taurine upregulated gene 1 (TUG1) is a long noncoding RNA (lncRNA) that is downregulated in sepsis. The current study was designed to explore the role of EPCs derived EVs transmitting TUG1 in macrophage polarization and macrophage-mediated inflammation in a cecal ligation and puncture (CLP)-induced sepsis mouse model. TUG1 was underexpressed in CLP-induced sepsis, and its reexpression induced anti-inflammatory macrophage polarization and suppressed macrophage-medicated inflammatory injury to the pulmonary vascular endothelium. EPCs derived EVs transmitted TUG1 to promote M2 macrophage polarization. Luciferase, RIP, and RNA pull-down assays showed that TUG1 could competitively bind to microRNA-9-5p (miR-9-5p) to upregulate the expression of sirtuin 1 (SIRT1). Furthermore, EPCs derived EVs transmitted TUG1 to promote M2 macrophage polarization through the impairment of miR-9-5p-dependent SIRT1 inhibition. Finally, EPCs derived EVs carrying TUG1 were verified to ameliorate sepsis-induced organ damage in the murine model. In summary, EPCs derived EVs transmit TUG1 to attenuate sepsis via macrophage M2 polarization. This study also highlights the proinflammatory mechanism associated with miR-9-5p-mediated inhibition of SIRT1, which contributes to a more comprehensive understanding of the pathogenesis of sepsis.

Hydrogen sulfide antagonizes sleep deprivation-induced depression- and anxiety-like behaviors by inhibiting neuroinflammation in a hippocampal Sirt1-dependent manner

Increasing evidence confirms that sleep deprivation (SD), which induces hippocampal neuroinflammation, is a risk factor for depression. Hydrogen sulfide (H₂S) is a novel neuromodulator that plays antidepressant-like role. Silent mating type information regulation 2 homolog 1 (Sirt1) is well-characterized as a regulator of mood disorder. Furthermore, we have previously reported that H₂S upregulates Sirt1 expression in the hippocampus of SD-exposed rats. Here, we explored whether H₂S ameliorates depression- and anxiety-like behaviors as well as hippocampal neuroinflammatory in SD-exposed rats and whether Sirt1 mediates these protective roles of H₂S. In the present work, we showed that NaHS (a donor of H₂S) significantly alleviated depression- and anxiety-like behaviors in the SD-exposed rats tested by novelty-suppressed feeding test (NST), forced swim test (FST), tail suspension test (TST), and elevated plus maze test (EPMT) and that NaHS attenuates neuroinflammatory in the hippocampus of SD-exposed rats, as evidenced by reducing the levels of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and chemokine CCL2, as well as increasing the levels of anti-inflammatory cytokines (IL-4 and IL-10) in the hippocampus. However, Sirt1 inhibitor reversed the protective effects of H₂S against SD-induced depression- and anxiety-like behaviors as well as hippocampal neuroinflammatory. In conclusion, H₂S antagonizes SD-induced depression- and anxiety-like behaviors and neuroinflammation, which is required hippocampal Sirt1. These findings suggested that H₂S is a novel approach to prevent SD-induced depression and anxiety.

Nicotinamide riboside, an NAD+ precursor, attenuates inflammation and oxidative stress by activating sirtuin 1 in alcohol-stimulated macrophages

Macrophages play an essential role in alcohol-induced inflammation and oxidative stress. We investigated the effects of nicotinamide riboside (NR), a natural nicotinamide adenine dinucleotide (NAD+) precursor, on alcohol-induced inflammation and oxidative stress in macrophages. NR significantly decreased ethanol-induced inflammatory gene expression, with a concomitant decrease in nuclear translocation of nuclear factor κB p65 in RAW 264.7 macrophages and mouse bone marrow-derived macrophages (BMDMs). In macrophages incubated with ethanol or acetaldehyde, NR abolished the accumulation of cellular reactive oxygen species. Ethanol decreased sirtuin 1 (SIRT1) expression and activity, and cellular NAD+ level while inducing pro-inflammatory gene expression. However, NR markedly attenuated the changes. SIRT1 inhibition augmented ethanol-induced inflammatory gene expression, but its activation elicited opposing effects. Also, ethanol did not alter glycolysis but increased glycolytic capacity, glycolytic reserve, and non-glycolytic acidification, with concomitant increases in hypoxia-induced factor 1α expression and activity, phosphorylation of pyruvate dehydrogenase, and extracellular lactate levels. Interestingly, ethanol increased mitochondrial respiration and ATP production but decreased maximal respiration and spare respiration capacity. The latter was linked to decreases in mitochondrial copy numbers. NR abolished the ethanol-induced metabolic changes in the glycolytic and oxidative phosphorylation pathways in RAW 264.7 macrophages. In conclusion, NR exerts anti-inflammatory and antioxidant properties by abrogating the inhibitory effects of ethanol on the SIRT1 pathway by increasing Sirt1 expression and its activator, NAD+. Also, SIRT1 activation and normalization of ethanol-induced changes in NAD+/NADH ratios by NR are likely crucial to counteract the changes in energy phenotypes of macrophages exposed to ethanol.

Role of Silent Information Regulator 1 (SIRT1) in Regulating Oxidative Stress and Inflammation

Silent information regulator 1 (SIRT1) is a ubiquitously expressed protein and has an intricate role in the pathology, progression, and treatment of several diseases. SIRT1 is a NAD+-dependent deacetylase and regulates gene expression by histone deacetylation. Deletion of SIRT1 in the liver, pancreas, and brain significantly increases the reactive oxygen species (ROS) and inflammatory response. Literature survey on SIRT1 shows the evidence for its role in preventing oxidative stress and inflammation. Oxidative stress and inflammation are closely related pathophysiological processes and are involved in the pathogenesis of a number of chronic disorders such as fatty liver diseases, diabetes, and neurodegenerative diseases. Both oxidative stress and inflammation alter the expression of several genes such as nuclear factor E2 related factor (Nrf2), nuclear factor E2 related factor 2 (Nef2), nuclear factor kappa B (NF-kB), pancreatic and duodenal homeobox factor 1 (PDX1), interleukin-1 (IL1), forkhead box class O (FOXO), and tumour necrosis factor alpha (TNF-α). By annotating this knowledge, we can conclude that modulating the expression of SIRT1 might prevent the onset of diseases inexorably linked to the liver, pancreas, and brain. Graphical Abstract Role of silent information regulator 1 (SIRT1) in the pancreas, brain, and liver.

The role of sirtuin 1 on the induction of trained immunity

Sirtuin 1 (SIRT1) has been described to modify immune responses by modulation of gene transcription. As transcriptional reprogramming is the molecular substrate of trained immunity, a de facto innate immune memory, we investigated the role of SIRT1 in the induction of trained immunity. We identified various SIRT1 genetic single nucleotide polymorphisms affecting innate and adaptive cytokine production of human peripheral blood mononuclear cells (PBMCs) in response to various stimuli on the one hand, and in vitro induction of trained immunity on the other hand. Furthermore, inhibition of SIRT1 upregulated pro-inflammatory innate cytokine production upon stimulation of PBMCs. However, inhibition of SIRT1 in vitro had no effect on cytokine responses upon induction of trained immunity, while activation of SIRT1 mildly modified trained immunity responses. In conclusion, SIRT1 modifies innate cytokine production by PBMCs in response to various microbes, but has only a secondary role for BCG and β-glucan-induced trained immunity responses.

Pathophysiological Aspects of Alcohol Metabolism in the Liver

Alcoholic liver disease (ALD) is a globally prevalent chronic liver disease caused by chronic or binge consumption of alcohol. The liver is the major organ that metabolizes alcohol; therefore, it is particularly sensitive to alcohol intake. Metabolites and byproducts generated during alcohol metabolism cause liver damage, leading to ALD via several mechanisms, such as impairing lipid metabolism, intensifying inflammatory reactions, and inducing fibrosis. Despite the severity of ALD, the development of novel treatments has been hampered by the lack of animal models that fully mimic human ALD. To overcome the current limitations of ALD studies and therapy development, it is necessary to understand the molecular mechanisms underlying alcohol-induced liver injury. Hence, to provide insights into the progression of ALD, this review examines previous studies conducted on alcohol metabolism in the liver. There is a particular focus on the occurrence of ALD caused by hepatotoxicity originating from alcohol metabolism.

Alcoholic and Non-Alcoholic Liver Diseases: Promising Molecular Drug Targets and their Clinical Development

Alcoholic and non-alcoholic fatty liver diseases have become a serious concern worldwide. Both these liver diseases have an identical pathology, starting from simple steatosis to cirrhosis and, ultimately to hepatocellular carcinoma. Treatment options for alcoholic liver disease (ALD) are still the same as they were 50 years ago which include corticosteroids, pentoxifylline, antioxidants, nutritional support and abstinence; and for non-alcoholic fatty liver disease (NAFLD), weight loss, insulin sensitizers, lipid-lowering agents and anti-oxidants are the only treatment options. Despite broad research in understanding the disease pathophysiology, limited treatments are available for clinical use. Some therapeutic strategies based on targeting a specific molecule have been developed to lessen the consequences of disease and are under clinical investigation. Therefore, focus on multiple molecular targets will help develop an efficient therapeutic strategy. This review comprises a brief overview of the pathogenesis of ALD and NAFLD; recent molecular drug targets explored for ALD and NAFLD that may prove to be effective for multiple therapeutic regimens and also the clinical status of these promising drug targets for liver diseases.

Translational Approaches with Antioxidant Phytochemicals against Alcohol-Mediated Oxidative Stress, Gut Dysbiosis, Intestinal Barrier Dysfunction, and Fatty Liver Disease

Emerging data demonstrate the important roles of altered gut microbiomes (dysbiosis) in many disease states in the peripheral tissues and the central nervous system. Gut dysbiosis with decreased ratios of Bacteroidetes/Firmicutes and other changes are reported to be caused by many disease states and various environmental factors, such as ethanol (e.g., alcohol drinking), Western-style high-fat diets, high fructose, etc. It is also caused by genetic factors, including genetic polymorphisms and epigenetic changes in different individuals. Gut dysbiosis, impaired intestinal barrier function, and elevated serum endotoxin levels can be observed in human patients and/or experimental rodent models exposed to these factors or with certain disease states. However, gut dysbiosis and leaky gut can be normalized through lifestyle alterations such as increased consumption of healthy diets with various fruits and vegetables containing many different kinds of antioxidant phytochemicals. In this review, we describe the mechanisms of gut dysbiosis, leaky gut, endotoxemia, and fatty liver disease with a specific focus on the alcohol-associated pathways. We also mention translational approaches by discussing the benefits of many antioxidant phytochemicals and/or their metabolites against alcohol-mediated oxidative stress, gut dysbiosis, intestinal barrier dysfunction, and fatty liver disease.

Role of ALDH2 in Hepatic Disorders: Gene Polymorphism and Disease Pathogenesis

Aldehyde dehydrogenase 2 (ALDH2) is a key enzyme of alcohol metabolism and it is involved in the cellular mechanism of alcohol liver disease. ALDH2 gene mutations exist in about 8% of the world's population, with the incidence reaching 45% in East Asia. The mutations will result in impairment of enzyme activity and accumulation of acetaldehyde, facilitating the progression of other liver diseases, including non-alcoholic fatty liver diseases, viral hepatitis and hepatocellular carcinoma, through adduct formation and inflammatory responses. In this review, we seek to summarize recent research progress on the correlation between ALDH2 gene polymorphism and multiple liver diseases, with an attempt to provide clues for better understanding of the disease mechanism and for strategy making.

Ethanol modulates the effector functions of human monocyte-derived macrophages in response to Paracoccidioides brasiliensis yeast cells

We aimed to investigate the effects of ethanol and its metabolites (β-hydroxybutyrate and sodium acetate) in the effector functions of macrophages in response to Paracoccidioides brasiliensis yeast cells and to determine their influence in the development of the adaptive response. Purified peripheral blood monocytes were differentiated into macrophages and were treated with ethanol, β-hydroxybutyrate, and sodium acetate, and stimulated with P. brasiliensis yeast cells and evaluated for their phenotypic characteristics, functional activity, and capability to induce T cells activation/differentiation. We found that the ethanol treatment diminished the expression of HLA-AB, HLA-DR, CD80, and CD86, modulating the expression of dectin-1, as well as Syk phosphorylation. The ethanol treatment increased the phagocytic activity, expression of CD206, and IL-10 production; however, reduced ROS production, fungicidal activity, caspase-1 cleavage, and IL-1β and IL-6 production. Our data also showed that the presence of ethanol reduced the differentiation of Th1 and Th17 cells and increased the frequency of Th2 cells. Our results indicated that ethanol exposure could suppress effector function of macrophages, possibly leading to the polarization of M2 macrophages. The ethanol modulates the expression of costimulatory and antigen-presentation molecules and interferes with the NLRP3 inflammasome. Altogether, these alterations affect the development of the adaptive response, decreasing the frequency of IL-17, IL-22, and IFN- γ producing cells, and increasing the frequency of IL-4 producing cells. Therefore, exposure to ethanol can impair the capability of macrophages to exert their effector functions and activate the acquired response related to resistance to P. brasiliensis infection.

Dual Effect of Soloxolone Methyl on LPS-Induced Inflammation In Vitro and In Vivo

Plant-extracted triterpenoids belong to a class of bioactive compounds with pleotropic functions, including antioxidant, anti-cancer, and anti-inflammatory effects. In this work, we investigated the anti-inflammatory and anti-oxidative activities of a semisynthetic derivative of 18βH-glycyrrhetinic acid (18βH-GA), soloxolone methyl (methyl 2-cyano-3,12-dioxo-18βH-olean-9(11),1(2)-dien-30-oate, or SM) in vitro on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and in vivo in models of acute inflammation: LPS-induced endotoxemia and carrageenan-induced peritonitis. SM used at non-cytotoxic concentrations was found to attenuate the production of reactive oxygen species and nitric oxide (II) and increase the level of reduced glutathione production by LPS-stimulated RAW264.7 cells. Moreover, SM strongly suppressed the phagocytic and migration activity of activated macrophages. These effects were found to be associated with the stimulation of heme oxigenase-1 (HO-1) expression, as well as with the inhibition of nuclear factor-κB (NF-κB) and Akt phosphorylation. Surprisingly, it was found that SM significantly enhanced LPS-induced expression of the pro-inflammatory cytokines interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) in RAW264.7 cells via activation of the c-Jun/Toll-like receptor 4 (TLR4) signaling axis. In vivo pre-exposure treatment with SM effectively inhibited the development of carrageenan-induced acute inflammation in the peritoneal cavity, but it did not improve LPS-induced inflammation in the endotoxemia model.

Emerging Roles of SIRT1 in Alcoholic Liver Disease

Alcoholic liver disease (ALD) is the most prevalent type of chronic liver disease worldwide with a wide spectrum of liver pathologies ranging from simple steatosis to steatohepatitis, cirrhosis, and even hepatocellular carcinoma. It has been demonstrated that ALD is mediated in whole or in part by a central signaling molecule sirtuin 1 (SIRT1), a conserved class III histone deacetylase.SIRT1 plays beneficial roles in regulating hepatic lipid metabolism, inhibiting hepatic inflammation, controlling hepatic fibrosis and mediating hepatocellular carcinoma in ALD. However, underlying molecular mechanisms are complex and remain incompletely understood. The aim of this review was to highlight the latest advances in understanding of SIRT1 regulatory mechanisms in ALD and discuss their unique potential role as novel therapeutic target for ALD treatment.

Moderate SIRT1 overexpression protects against brown adipose tissue inflammation

OBJECTIVE

Metainflammation is a chronic low-grade inflammatory state induced by obesity and associated comorbidities, including peripheral insulin resistance. Brown adipose tissue (BAT), a therapeutic target against obesity, is an insulin target tissue sensitive to inflammation. Therefore, it is necessary to find strategies to protect BAT against the effects of inflammation in energy balance. In this study, we explored the impact of moderate sirtuin 1 (SIRT1) overexpression on insulin sensitivity and β-adrenergic responses in BAT and brown adipocytes (BA) under pro-inflammatory conditions.

METHODS

The effect of inflammation on BAT functionality was studied in obese db/db mice and lean wild-type (WT) mice or mice with moderate overexpression of SIRT1 (SIRT1^Tg+) injected with a low dose of bacterial lipopolysaccharide (LPS) to mimic endotoxemia. We also conducted studies on differentiated BA (BA-WT and BA-SIRT1^Tg+) exposed to a macrophage-derived pro-inflammatory conditioned medium (CM) to evaluate the protection of SIRT1 overexpression in insulin signaling and glucose uptake, mitochondrial respiration, fatty acid oxidation (FAO), and norepinephrine (NE)-mediated-modulation of uncoupling protein-1 (UCP-1) expression.

RESULTS

BAT from the db/db mice was susceptible to metabolic inflammation manifested by the activation of pro-inflammatory signaling cascades, increased pro-inflammatory gene expression, tissue-specific insulin resistance, and reduced UCP-1 expression. Impairment of insulin and noradrenergic responses were also found in the lean WT mice upon LPS injection. In contrast, BAT from the mice with moderate overexpression of SIRT1 (SIRT1^Tg+) was protected against LPS-induced activation of pro-inflammatory signaling, insulin resistance, and defective thermogenic-related responses upon cold exposure. Importantly, the decline in triiodothyronine (T₃) levels in the circulation and intra-BAT after exposure of the WT mice to LPS and cold was markedly attenuated in the SIRT1^Tg+ mice. In vitro BA experiments in the two genotypes revealed that upon differentiation with a T₃-enriched medium and subsequent exposure to a macrophage-derived pro-inflammatory CM, only BA-SIRT1^Tg+ fully recovered insulin and noradrenergic responses.

CONCLUSIONS

This study has ascertained the benefit of the moderate overexpression of SIRT1 to confer protection against defective insulin and β-adrenergic responses caused by BAT inflammation. Our results have potential therapeutic value in combinatorial therapies for BAT-specific thyromimetics and SIRT1 activators to combat metainflammation in this tissue.

Triterpenoids Extracted From Antrodia cinnamomea Mycelia Attenuate Acute Alcohol-Induced Liver Injury in C57BL/6 Mice via Suppression Inflammatory Response

Excessive alcohol consumption causes liver injury–induced mortality. Here we systematically analyzed the structure of triterpenoids extracted from Antrodia cinnamomea mycelia (ACT) and investigated their protective effects against acute alcohol-induced liver injury in mice. Liquid chromatography–mass spectrometry and liquid chromatography with tandem mass spectrometry were performed to determine the structures of ACT constituents. Alcohol-induced liver injury was generated in C57BL/6 mice by oral gavage of 13 g/kg white spirit (a wine at 56% ABV). Mice were treated with either silibinin or ACT for 2 weeks. Liver injury markers and pathological signaling were then quantified with enzyme-linked immunosorbent assays, antibody array assays, and Western blots, and pathological examinations were performed using hematoxylin-eosin staining and periodic acid–Schiff staining. Triterpenoids extracted from A. cinnamomea mycelia contain 25 types of triterpenoid compounds. A 2-weeks alcohol consumption treatment caused significant weight loss, liver dyslipidemia, and elevation of alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, and alkaline phosphatase activities in the serum and/or liver. These effects were markedly reversed after 2-weeks ACT administration. Triterpenoids extracted from A. cinnamomea mycelia alleviated the organ structural changes and inflammatory infiltration of alcohol-damaged tissues. Triterpenoids extracted from A. cinnamomea mycelia inhibited proinflammatory cytokine levels and enhanced anti-inflammatory cytokine levels. Acute alcohol treatment promoted inflammation with significant correlations to hypoxia-inducible factor 1α (HIF-1α), which was reduced by ACT and was partially related to modulation of the protein kinase B (Akt)/70-kDa ribosomal protein S6 kinase phosphorylation (p70S6K) and Wnt/β-catenin signaling pathways. In conclusion, ACT protected against acute alcohol-induced liver damage in mice mainly through its suppression of the inflammatory response, which may be related to HIF-1α signaling.

Bergenin-activated SIRT1 inhibits TNF-α-induced proinflammatory response by blocking the NF-κB signaling pathway

BACKGROUND

Bergenin, a type of polyphenol compound, exhibits antiulcerogenic, anti-inflammatory, antitussive, and burn wound-healing properties. However, its therapeutic effect on tumor necrosis factor α (TNF-α)-induced proinflammatory responses in the airway and potential mechanisms of actions are still unclear. This study aimed to investigate the anti-inflammatory effects and mechanism of bergenin in TNF-α-stimulated human bronchial epithelial (16-HBE) cells.

METHODS

Cell Counting Kit-8 was used to evaluate cytotoxicity. Cytokine expression was analyzed by reverse transcription-quantitative PCR (RT-qPCR) and enzyme-linked immunosorbent assay. Immunofluorescence, western blot, and sirtuin-1 (SIRT1) activity assays were employed to investigate potential molecular mechanisms.

RESULTS

Bergenin obviously decreased both mRNA and protein expression levels of interleukins 6 and 8 (IL-6 and IL-8) in TNF-α-stimulated 16-HBE cells. Bergenin blocked TNF-α-mediated activation of nuclear factor κB (NF-κB) signaling and NF-κB nuclear translocation. Interestingly, RT-qPCR and western blotting results revealed that bergenin did not affect SIRT1 expression, but significantly increased its activity. Bergenin-mediated SIRT1 activation was further confirmed by results indicating decreased acetylation levels of NF-κB-p65 and p53. Moreover, the inhibitory effects of bergenin on mRNA and protein expression levels of IL-6 and IL-8 were reversed by a SIRT1 inhibitor. In addition, combining bergenin and dexamethasone (DEX) yielded additive effects on the reduction of IL-6 and IL-8 expression.

CONCLUSIONS

These findings demonstrate that bergenin could suppress TNF-α-induced proinflammatory responses by augmenting SIRT1 activity to block the NF-κB signaling pathway, which may provide beneficial effects for the treatment of airway inflammation associated with asthma.

Transcriptional, Epigenetic and Metabolic Programming of Tumor-Associated Macrophages

Macrophages are key innate immune cells in the tumor microenvironment (TME) that regulate primary tumor growth, vascularization, metastatic spread and tumor response to various types of therapies. The present review highlights the mechanisms of macrophage programming in tumor microenvironments that act on the transcriptional, epigenetic and metabolic levels. We summarize the latest knowledge on the types of transcriptional factors and epigenetic enzymes that control the direction of macrophage functional polarization and their pro- and anti-tumor activities. We also focus on the major types of metabolic programs of macrophages (glycolysis and fatty acid oxidation), and their interaction with cancer cells and complex TME. We have discussed how the regulation of macrophage polarization on the transcriptional, epigenetic and metabolic levels can be used for the efficient therapeutic manipulation of macrophage functions in cancer.

Ring finger protein 219 regulates inflammatory responses by stabilizing sirtuin 1

BACKGROUND AND PURPOSE

Ring finger protein 219 (RNF219), a protein containing the C₃ HC₄ -type RING-HC motif, has been identified as a binding partner of the histone deacetylase sirtuin 1 (SIRT1). To explore the functions of RNF219, we examined its possible roles in the cellular responses to inflammation.

EXPERIMENTAL APPROACH

Effects of RNF219 on SIRT1 were studied in vitro using RAW264.7 cells and in male BALB/c mice, treated with LPS or IFN-γ. Western blots, RT-PCR, co-immunoprecipitation and ubiquitination assays were used, along with LC-MS/MS analysis. In vivo, survival and serum cytokines and tissue levels of RNF219 and SIRT1 were measured.

KEY RESULTS

Binding of RNF219 to SIRT1 inhibited degradation of SIRT1 by preventing its ubiquitination, thereby prolonging SIRT1-mediated anti-inflammatory signalling. LPS caused RNF219 deacetylation, leading to instability of RNF219 and preventing its association with SIRT1. Accordingly, the acetylation status of RNF219 is a critical determinant in its interaction with SIRT1, affecting the response to inflammatory stimuli. The deacetylase inhibitor trichostatin A, increased acetylation and stability of RNF219 and survival of mice injected with LPS, through the interaction of RNF219 with SIRT1.

CONCLUSION AND IMPLICATIONS

RNF219 is involved in a novel mechanism to stabilize SIRT1 protein by protein-protein interaction, leading to the resolution of cellular inflammation. These observations provide new insights into the function of RNF219 in modulation of cellular inflammation, and may aid and encourage the development of new anti-inflammatory drugs.

SIRT1 Alleviates LPS-Induced IL-1β Production by Suppressing NLRP3 Inflammasome Activation and ROS Production in Trophoblasts

Emerging evidence indicates that aberrant maternal inflammation is associated with several pregnancy-related disorders such as preeclampsia, preterm birth, and intrauterine growth restriction. Sirtuin1 (SIRT1), a class III histone deacetylase, is involved in the regulation of various physiopathological processes including cellular inflammation and metabolism. However, the effect of SIRT1 on the placental proinflammatory environment remains to be elucidated. In this study, we investigated the effect of SIRT1 on lipopolysaccharide (LPS)-induced NLRP3 inflammasome activation and its underlying mechanisms in human first-trimester trophoblasts (Sw.71 and HTR-8/SVneo cells). Treatment with LPS elevated SIRT1 expression and induced NLRP3 inflammasome activation in mouse placental tissues and human trophoblasts. Knockdown of SIRT1 enhanced LPS-induced NLRP3 inflammasome activation, inflammatory signaling, and subsequent interleukin (IL)-1β secretion. Furthermore, knockdown of NLRP3 considerably attenuated the increase of IL-1β secretion in SIRT1-knockdown cells treated with LPS. Moreover, SIRT1 inhibited LPS-induced NLRP3 inflammasome activation by reducing oxidative stress. This study revealed a novel mechanism via which SIRT1 exerts anti-inflammatory effects, suggesting that SIRT1 is a potential therapeutic target for the prevention of inflammation-associated pregnancy-related complications.

Modulatory Role of SIRT1 and Resistin as Therapeutic Targets in Patients with Aortic Valve Stenosis

BACKGROUND

Inflammatory is one of the main cause of aortic valve stenosis (AS), so discovering novel biomarkers for the targeted therapy of inflammation could be an attractive strategy in AS prevention. The objectives of our study were to clarify the modulatory role of resistin and silent information regulator 1 (SIRT1) before and after surgery and also to evaluate the therapeutic effects of resveratrol.

METHODS

Nineteen AS patients and 15 healthy subjects were studied as the case and control groups, respectively. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured to determine the levels of resistin and SIRT1 and the effects of resveratrol on them.

RESULTS

Significant increase in resistin expression was observed in the patients compare to the control (p ≤0.01), and this upregulation was augmented 72 h following surgery (p ≤0.01). The SIRT1 expression decreased in the AS group compare to the control but this reduction was not significant. Aortic valve replacement caused a higher decrease in the protein (p ≤0.01) and mRNA level (p ≤0.05) of SIRT1. Resveratrol in the AS group significantly diminished the resistin level (p ≤0.05) but increased the SIRT1 level (p ≤0.001).

CONCLUSIONS

In our patients with AS, the resistin level was increased, whereas the expression of SIRT1 was reduced and surgery augmented these alterations. Resveratrol improved inflammation in the PBMCs of the patients through the SIRT1/resistin pathway. These findings suggest that pharmacological therapy with resveratrol might be a novel approach to alleviating inflammation in patients with AS.

Akt1 and Akt2 Isoforms Play Distinct Roles in Regulating the Development of Inflammation and Fibrosis Associated with Alcoholic Liver Disease

Akt kinase isoforms (Akt1, Akt2, and Akt3) have generally been thought to play overlapping roles in phosphoinositide 3-kinase (PI3K)-mediated-signaling. However, recent studies have suggested that they display isoform-specific roles in muscle and fat. To determine whether such isoform-specificity is observed with respect to alcoholic liver disease (ALD) progression, we examined the role of Akt1, Akt2, and Akt3 in hepatic inflammation, and pro-fibrogenic proliferation and migration using Kupffer cells, hepatic stellate cells (HSC), and hepatocytes in an ethanol and lipopolysaccharide (LPS)-induced two-hit model in vitro and in vivo. We determined that siRNA-directed silencing of Akt2, but not Akt1, significantly suppressed cell inflammatory markers in HSC and Kupffer cells. Although both Akt1 and Akt2 inhibited cell proliferation in HSC, only Akt2 inhibited cell migration. Both Akt1 and Akt2, but not Akt3, inhibited fibrogenesis in hepatocytes and HSC. In addition, our in vivo results show that administration of chronic ethanol, binge ethanol and LPS (EBL) in wild-type C57BL/6 mice activated all three Akt isoforms with concomitant increases in activated forms of phosphoinositide dependent kinase-1 (PDK1), mammalian target-of-rapamycin complex 2 (mTORC2), and PI3K, resulting in upregulation in expression of inflammatory, proliferative, and fibrogenic genes. Moreover, pharmacological blocking of Akt2, but not Akt1, inhibited EBL-induced inflammation while blocking of both Akt1 and Akt2 inhibited pro-fibrogenic marker expression and progression of fibrosis. Our findings indicate that Akt isoforms play unique roles in inflammation, cell proliferation, migration, and fibrogenesis during EBL-induced liver injury. Thus, close attention must be paid when targeting all Akt isoforms as a therapeutic intervention.

Resveratrol inhibited LPS induced transcription of immune genes and secretion of eicosanoids in Atlantic salmon (Salmo salar), comparing mono-, co- and a novel triple cell culture model of head kidney leukocytes, liver cells and visceral adipocyte tissue

The aim was to study the effect of resveratrol on the interplay of inflammatory signals using three different cell models; a metabolic organ (liver), an endocrine organ (visceral adipose tissue, VAT) and an immune organ (head kidney leukocytes, HKL) following lipopolysaccharide challenge (LPS). Atlantic salmon HKL, liver cells and VAT were isolated from the same fish (n = 5). Each cell type was cultured either as mono-cultures, as co-cultures between HKL-liver cells, liver cells-VAT and HKL-VAT. Triple -cultures included all three tissues. In all cultures of HKL, LPS induced transcription of IL-1β, cox2, tnfα, IL-12, ccattβ and Ahr were significantly inhibited by resveratrol (100, 200 μM). Likewise, in all cultures of liver cells, the LPS induced expression of IL-1β was inhibited by resveratrol (100 and 200 μM). HKL, both mono-cultures and triple-cultures and VAT cocultured with liver cells, showed LPS induced cox2 transcription that was inhibited by resveratrol (100 and 200 μM). In contrast, VAT cultured as triple cultures, resveratrol 200 μM particularly, in the presence of LPS, seemed to increase the expression of IL-1β and ccattβ. Resveratrol did not significantly affect lox5 expression in any culture. HKL and VAT are the main producers of PGE2 in response to inflammatory stimuli. VAT showed high endogenous production of eicosanoids, particularly LTB4 and LTB5. Resveratrol inhibited bot LPS induced and endogenous eicosanoid production. Possible targets of resveratrol, Sirt1 and pAMPK were affected differently in the different cells and tissue studied.

Gut microbial metabolites in obesity, NAFLD and T2DM

Evidence is accumulating that the gut microbiome is involved in the aetiology of obesity and obesity-related complications such as nonalcoholic fatty liver disease (NAFLD), insulin resistance and type 2 diabetes mellitus (T2DM). The gut microbiota is able to ferment indigestible carbohydrates (for example, dietary fibre), thereby yielding important metabolites such as short-chain fatty acids and succinate. Numerous animal studies and a handful of human studies suggest a beneficial role of these metabolites in the prevention and treatment of obesity and its comorbidities. Interestingly, the more distal colonic microbiota primarily ferments peptides and proteins, as availability of fermentable fibre, the major energy source for the microbiota, is limited here. This proteolytic fermentation yields mainly harmful products such as ammonia, phenols and branched-chain fatty acids, which might be detrimental for host gut and metabolic health. Therefore, a switch from proteolytic to saccharolytic fermentation could be of major interest for the prevention and/or treatment of metabolic diseases. This Review focuses on the role of products derived from microbial carbohydrate and protein fermentation in relation to obesity and obesity-associated insulin resistance, T2DM and NAFLD, and discusses the mechanisms involved.

Signal Transduction Mechanisms of Alcoholic Fatty Liver Disease: Emer ging Role of Lipin-1

Lipin-1, a mammalian phosphatidic acid phosphatase (PAP), is a bi-functional molecule involved in various signaling pathways via its function as a PAP enzyme in the triglyceride synthesis pathway and in the nucleus as a transcriptional co-regulator. In the liver, lipin-1 is known to play a vital role in controlling the lipid metabolism and inflammation process at multiple regulatory levels. Alcoholic fatty liver disease (AFLD) is one of the earliest forms of liver injury and approximately 8-20% of patients with simple steatosis can develop into more severe forms of liver injury, including steatohepatitis, fibrosis/ cirrhosis, and eventually hepatocellular carcinoma (HCC). The signal transduction mechanisms for alcohol-induced detrimental effects in liver involves alteration of complex and multiple signaling pathways largely governed by a central and upstream signaling system, namely, sirtuin 1 (SIRT1)-AMP activated kinase (AMPK) axis. Emerging evidence suggests a pivotal role of lipin-1 as a crucial downstream regulator of SIRT1-AMPK signaling system that is likely to be ultimately responsible for development and progression of AFLD. Several lines of evidence demonstrate that ethanol exposure significantly induces lipin-1 gene and protein expression levels in cultured hepatocytes and in the livers of rodents, induces lipin-1-PAP activity, impairs the functional activity of nuclear lipin-1, disrupts lipin-1 mRNA alternative splicing and induces lipin-1 nucleocytoplasmic shuttling. Such impairment in response to ethanol leads to derangement of hepatic lipid metabolism, and excessive production of inflammatory cytokines in the livers of the rodents and human alcoholics. This review summarizes current knowledge about the role of lipin-1 in the pathogenesis of AFLD and its potential signal transduction mechanisms.

Resveratrol regulates the silent information regulator 1-nuclear factor-κB signaling pathway in intrahepatic cholestasis of pregnancy

AIM

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disease characterized by raised serum bile acids and adverse fetal outcomes. In this study, we aimed to explore the molecular and biochemical mechanism of resveratrol in regulating the silent information regulator 1-nuclear factor-κB (SIRT1-NF-κB) signaling pathway and bile acid biosynthesis in ICP.

METHODS

We analyzed serum and placenta samples from 30 normal and ICP pregnancy women. Then we treated HTR-8/SVneo cells with taurocholic acid (TCA) to mimic ICP conditions before treating these cells with resveratrol, as an activator of SIRT1, and EX-57, as an inhibitor of SIRT1. We established an ICP rat model to analyze the therapeutic effect of resveratrol.

RESULTS

The expression of SIRT1 protein was higher in normal placenta tissues than in ICP, and the expression of NF-κB was lower in the normal group than in the ICP group. We found that SIRT1 was downregulated, whereas NF-κB and tuor necrosis factor-α (TNF-α) were upregulated, in syncytiotrophoblast HTR-8 cells treated with TCA. This phenomenon could be reversed by resveratrol, and these effects could be blocked by Ex-527.

CONCLUSION

These data indicate that resveratrol might protect syncytiotrophoblast against TCA-induced inflammatory injury by upregulation of SIRT1 and downregulation of NF-κB and TNF-α. Resveratrol could be a potential therapeutic target for ICP.

Controversial Impact of Sirtuins in Chronic Non-Transmissible Diseases and Rehabilitation Medicine

A large body of evidence reports about the positive effects of physical activity in pathophysiological conditions associated with aging. Physical exercise, alone or in combination with other medical therapies, unquestionably causes reduction of symptoms in chronic non-transmissible diseases often leading to significant amelioration or complete healing. The molecular basis of this exciting outcome—however, remain largely obscure. Epigenetics, exploring at the interface between environmental signals and the remodeling of chromatin structure, promises to shed light on this intriguing matter possibly contributing to the identification of novel therapeutic targets. In this review, we shall focalize on the role of sirtuins (Sirts) a class III histone deacetylases (HDACs), which function has been frequently associated, often with a controversial role, to the pathogenesis of aging-associated pathophysiological conditions, including cancer, cardiovascular, muscular, neurodegenerative, bones and respiratory diseases. Numerous studies, in fact, demonstrate that Sirt-dependent pathways are activated upon physical and cognitive exercises linking mitochondrial function, DNA structure remodeling and gene expression regulation to designed medical therapies leading to tangible beneficial outcomes. However, in similar conditions, other studies assign to sirtuins a negative pathophysiological role. In spite of this controversial effect, it is doubtless that studying sirtuins in chronic diseases might lead to an unprecedented improvement of life quality in the elderly.

Urine metabolic fingerprinting can be used to predict the risk of metritis and highlight the pathobiology of the disease in dairy cows

INTRODUCTION

Metritis is an uterine pathology that causes economic losses for the dairy industry. It is associated with lower reproductive efficiency, increased culling rates, decreased milk production and increased veterinary costs.

OBJECTIVES

To gain a more detailed view of the urine metabolome and to detect metabolite signature in cows with metritis. In addition, we aimed to identify early metabolites which can help to detect cows at risk to develop metritis in the future.

METHODS

We used nuclear magnetic resonance spectroscopy starting at 8 and 4 weeks prior to the expected day of parturition, during the week of diagnosis of metritis, and at 4 and 8 weeks after diagnosis of metritis in Holstein dairy cows.

RESULTS

At 8 weeks before parturition, pre-metritic cows had a total of 30 altered metabolites. Interestingly, 28 of them increased in urine when compared with control cows (P < 0.05). At 4 weeks before parturition, 34 metabolites were altered. At the week of diagnosis of metritis a total of 20 metabolites were altered (P < 0.05). The alteration continued at 4 and 8 weeks after diagnosis.

CONCLUSIONS

The metabolic fingerprints in the urine of pre-metritic and metritic cows point toward excretion of multiple amino acids, tricarboxylic acid cycle metabolites and monosaccharides. Combination of galactose, leucine, lysine and panthotenate at 8 weeks before parturition might serve as predictive biomarkers for metritis.

Hepatocyte toll-like receptor 4 deficiency protects against alcohol-induced fatty liver disease

Objective

Recent studies have suggested a critical role for toll-like receptor 4 (TLR4) in the development of alcoholic liver disease. As TLR4 is widely expressed throughout the body, it is unclear which TLR4-expressing cell types contribute to alcohol-induced liver damage.

Methods

We selectively ablated TLR4 in hepatocytes and myeloid cells. Male mice were fed a liquid diet containing either 5% alcohol or pair-fed a control diet for 4 weeks to examine chronic alcohol intake-induced liver damage and inflammation. In addition, mice were administered a single oral gavage of alcohol to investigate acute alcohol drinking-associated liver injury.

Results

We found that selective hepatocyte TLR4 deletion protected mice from chronic alcohol-induced liver injury and fatty liver. This result was in part due to decreased expression of endogenous lipogenic genes and enhanced expression of genes involved in fatty acid oxidation. In addition, mice lacking hepatocyte TLR4 exhibited reduced mRNA expression of inflammatory genes in white adipose tissue. Furthermore, in an acute alcohol binge model, hepatocyte TLR4 deficient mice had significantly decreased plasma alanine transaminase (ALT) levels and attenuated hepatic triglyceride content compared to their alcohol-gavaged control mice. In contrast, deleting TLR4 in myeloid cells did not affect the development of chronic-alcohol induced fatty liver, despite the finding that mice lacking myeloid cell TLR4 had significantly reduced circulating ALT concentrations.

Conclusions

These findings suggest that hepatocyte TLR4 plays an important role in regulating alcohol-induced liver damage and fatty liver disease.

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Hepatocyte TLR4 ablated mice were protected from both chronic and acute alcohol-induced hepatic triglyceride accumulation.

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Hepatocyte TLR4 ablated mice showed attenuated inflammation in the fat pad and the circulation after chronic alcohol intake.

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Loss of TLR4 in myeloid cells did not affect alcohol-induced development of fatty liver.

Endocrine Adiponectin-FGF15/19 Axis in Ethanol-Induced Inflammation and Alcoholic Liver Injury

Alcoholic liver disease (ALD) is the most prevalent form of liver disease, encompassing a spectrum of progressive pathological changes from steatosis to steatohepatitis to fibrosis/cirrhosis and hepatocellular carcinoma. Alcoholic steatosis/steatohepatitis is the initial stage of ALD and a major risk factor for advanced liver injuries. Adiponectin is a hormone secreted from adipocytes. Fibroblast growth factor (FGF) 15 (human homolog, FGF19) is an ileum-derived hormone. Adipocyte-derived adiponectin and gut-derived FGF15/19 regulate each other, share common signaling cascades, and exert similar beneficial functions. Emerging evidence has revealed that dysregulated adiponectin-FGF15/19 axis and impaired hepatic adiponectin-FGF15/19 signaling are associated with alcoholic liver damage in rodents and humans. More importantly, endocrine adiponectin-FGF15/19 signaling confers protection against ethanol-induced liver damage via fine tuning the adipose-intestine-liver crosstalk, leading to limited hepatic inflammatory responses, and ameliorated alcoholic liver injury. This review is focused on the recently discovered endocrine adiponectin-FGF15/19 axis that is emerging as an essential adipose-gut-liver coordinator involved in the development and progression of alcoholic steatohepatitis.

Resveratrol protects from lipopolysaccharide-induced inflammation in the uterus and prevents experimental preterm birth

STUDY QUESTION

Is resveratrol able to prevent the lipopolysaccharide (LPS)-induced preterm labor in 15-day pregnant BALB/c mice?

SUMMARY ANSWER

Resveratrol prevented the LPS-induced onset of preterm labor in 64% of the cases and showed anti-inflammatory and tocolytic effects by downregulating COX-2 and iNOS expression and NOS activity, and by changing the uterine prostaglandin and endocannabinoid profiling.

WHAT IS KNOWN ALREADY

Genital tract infections by Gram-negative bacteria are a common complication in human pregnancy and have been shown to increase risk of preterm delivery. Bacterial LPS elicits a strong maternal inflammatory response that results in preterm delivery and fetal death in a murine model endotoxin-induced preterm labor.

STUDY DESIGN, SIZE, DURATION

An in vivo animal study was conducted. On Day 15 of pregnancy, mice received at 8:00 h a dose of vehicle (40% ethanol in saline solution) or resveratrol (3 mg/kg in vehicle) via oral gavage followed by two doses of LPS or vehicle administered intraperitoneally (i.p.), the first one at 10:00 h (0.17 mg/kg in 0.1 ml of sterile saline solution) and the second at 13:00 h (0.5 mg/kg in 0.1 ml of sterile saline solution). The mice were closely observed for any signs of morbidity (piloerection, decreased movement, and diarrhea), vaginal bleeding or preterm delivery. The beginning of preterm delivery was defined by early delivery of the first pup. Normal term labor occurs on Day 19 of gestation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Time of labor, pregnancy outcome and morphological features were evaluated after LPS and/or resveratrol administration. Uterine stripes were collected 5 h after the last LPS injection and prostaglandin and endocannabinoid profiling was analyzed by mass spectrometry. Nitric oxide synthase (NOS) activity was measured by radioconversion assay. Cyclooxygenase-2 (Cox-2) and 15-hydroxyprostaglandin dehydrogenase (15-Pgdh) mRNA levels were analyzed by RT-PCR whilst the protein expression of inducible nitric oxide synthase (iNOS), COX-1 and COX-2 were studied by western blot.

MAIN RESULTS AND THE ROLE OF CHANCE

In vivo treatment of 15-day pregnant BALB/c mice with resveratrol prevented the LPS-induced preterm birth in 64% of the cases, whereas only 15% of mice with LPS alone escaped preterm birth. Treatment with resveratrol resulted in a reduced NOS activity (P < 0.05) in the uterus of LPS-treated mice. Similarly, resveratrol reduced the expression of LPS-induced pro-inflammatory agents such as iNOS (P < 0.05), COX-2 (P < 0.05), prostaglandin E2 (PGE2) (P < 0.05) and anandamide (AEA) (P < 0.05). Moreover, resveratrol administration resulted in changes in the uterine endocannabinoid profiling altered by LPS.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Since our experimental design involves the use of mice, the extrapolation of the results presented here to humans is limited.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings provide evidence for the tocolytic effects of resveratrol.

STUDY FUNDING AND COMPETING INTEREST(S)

Dr Ana María Franchi was funded by Agencia Nacional para la Promoción Científica y Tecnológica (PICT 2013/0097) and by Consejo Nacional de Investigaciones Científicas y Técnicas (PIP 2012/0061). Dr Heather B. Bradshaw was funded by NIH (DA006668). The authors have no competing interests.