Astaxanthin inhibits alcohol-induced inflammation and oxidative stress in macrophages in a sirtuin 1-dependent manner

Fucoxanthin Abrogates Ionizing Radiation-Induced Inflammatory Responses by Modulating Sirtuin 1 in Macrophages

Ionizing radiation (IR) triggers an overproduction of reactive oxygen species (ROS), disrupting the normal function of both immune and metabolic systems, leading to inflammation and metabolic disturbances. To address the pressing requirement for protection against IR, fucoxanthin (FX), a naturally occurring compound extracted from algae, was utilized as an efficient radioprotective agent in macrophages. In this study, we cultured murine RAW 264.7 macrophages and treated them with FX, along with agents influencing the activity of sirtuin 1 (SIRT1) and estrogen receptor α (ERα), to investigate their impact on IR-induced cellular responses. FX significantly attenuated IR-induced upregulation of pro-inflammatory genes (Il1b, Tnf, and Ccl2) and inhibited macrophage polarization toward the pro-inflammatory M1 phenotype. Additionally, FX regulated IR-induced metabolic genes mediating glycolysis and mitochondrial biogenesis. The ability of FX to mitigate IR-induced inflammation and glycolysis was ascribed to the expression and activity of SIRT1 and ERα in macrophages. This study not only uncovers the underlying mechanisms of FX's radioprotective properties but also highlights its potential as a protective agent against the detrimental effects of IR, thus offering new opportunities for enhancing radiation protection in the future.

Regulation of Acetylation States by Nutrients in the Inhibition of Vascular Inflammation and Atherosclerosis

Atherosclerosis (AS) is a chronic metabolic disorder and primary cause of cardiovascular diseases, resulting in substantial morbidity and mortality worldwide. Initiated by endothelial cell stimulation, AS is characterized by arterial inflammation, lipid deposition, foam cell formation, and plaque development. Nutrients such as carotenoids, polyphenols, and vitamins can prevent the atherosclerotic process by modulating inflammation and metabolic disorders through the regulation of gene acetylation states mediated with histone deacetylases (HDACs). Nutrients can regulate AS-related epigenetic states via sirtuins (SIRTs) activation, specifically SIRT1 and SIRT3. Nutrient-driven alterations in the redox state and gene modulation in AS progression are linked to their protein deacetylating, anti-inflammatory, and antioxidant properties. Nutrients can also inhibit advanced oxidation protein product formation, reducing arterial intima-media thickness epigenetically. Nonetheless, knowledge gaps remain when it comes to understanding effective AS prevention through epigenetic regulation by nutrients. This work reviews and confirms the underlying mechanisms by which nutrients prevent arterial inflammation and AS, focusing on the epigenetic pathways that modify histones and non-histone proteins by regulating redox and acetylation states through HDACs such as SIRTs. These findings may serve as a foundation for developing potential therapeutic agents to prevent AS and cardiovascular diseases by employing nutrients based on epigenetic regulation.

Astaxanthin promotes mitochondrial biogenesis and antioxidant capacity in chronic high-intensity interval training

PURPOSE

Reactive oxygen and nitrogen species are required for exercise-induced molecular adaptations; however, excessive exercise may cause cellular oxidative distress. We postulate that astaxanthin (ASX) can neutralize oxidative distress and stimulate mitochondrial biogenesis in high-intensity exercise-trained mice.

METHODS

Six-week-old mice (n = 8/group) were treated with ASX (10 mg/kg BW) or placebo. Training groups participated in 30 min/day high-intensity interval training (HIIT) for 6 weeks. Gastrocnemius muscle was collected and assayed following the exercise training period.

RESULTS

Compared to the HIIT control mice, the ASX-treated HIIT mice reduced malonaldehyde levels and upregulated the expression of Nrf2 and FOXO3a. Meanwhile, the genes NQO1 and GCLC, modulated by Nrf2, and SOD2, regulated by FOXO3a, and GPx4, were transcriptionally upregulated in the ASX-treated HIIT group. Meanwhile, the expression of energy sensors, AMPK, SIRT1, and SIRT3, increased in the ASX-treated HIIT group compared to the HIIT control group. Additionally, PGC-1α, regulated by AMPK and SIRT1, was upregulated in the ASX-treated HIIT group. Further, the increased PGC-1α stimulated the transcript of NRF1 and Tfam and mitochondrial proteins IDH2 and ATP50. Finally, the ASX-treated HIIT mice had upregulations in the transcript level of mitochondrial fusion factors, including Mfn1, Mfn2, and OPA1. However, the protein level of AMPK, SIRT1, and FOXO3a, and the transcript level of Nrf2, NQO1, PGC-1α, NRF1, Mfn1, Mfn2, and OPA1 decreased in the HIIT control group compared to the sedentary control group.

CONCLUSION

Supplementation with ASX can reduce oxidative stress and promote antioxidant capacity and mitochondrial biogenesis during strenuous HIIT exercise in mice.

Inhibitory Effects of Ginsenoside Compound K on Lipopolysaccharide-Stimulated Inflammatory Responses in Macrophages by Regulating Sirtuin 1 and Histone Deacetylase 4

Inflammation, an innate immune response mediated by macrophages, has been a hallmark leading to the pathophysiology of diseases. In this study, we examined the inhibitory effects of ginsenoside compound K (CK) on lipopolysaccharide (LPS)-induced inflammation and metabolic alteration in RAW 264.7 macrophages by regulating sirtuin 1 (SIRT1) and histone deacetylase 4 (HDAC4). LPS suppressed SIRT1 while promoting HDAC4 expression, accompanied by increases in cellular reactive oxygen species accumulation and pro-inflammatory gene expression; however, the addition of CK elicited the opposite effects. CK ameliorated the LPS-induced increase in glycolytic genes and abrogated the LPS-altered genes engaged in the NAD+ salvage pathway. LPS decreased basal, maximal, and non-mitochondrial respiration, reducing ATP production and proton leak in macrophages, which were abolished by CK. SIRT1 inhibition augmented Hdac4 expression along with increased LPS-induced inflammatory and glycolytic gene expression, while decreasing genes that regulate mitochondrial biogenesis; however, its activation resulted in the opposite effects. Inhibition of HDAC4 enhanced Sirt1 expression and attenuated the LPS-induced inflammatory gene expression. In conclusion, CK exerted anti-inflammatory and antioxidant properties with the potential to counteract the alterations of energy metabolism, including glycolysis and mitochondrial respiration, through activating SIRT1 and repressing HDAC4 in LPS-stimulated macrophages.

Colloidal Nanoparticles Isolated from Duck Soup Exhibit Antioxidant Effect on Macrophages and Enterocytes

Food-derived colloidal nanoparticles (CNPs) have been found in many food cooking processes, and their specific effects on human health need to be further explored. Here, we report on the successful isolation of CNPs from duck soup. The hydrodynamic diameters of the obtained CNPs were 255.23 ± 12.77 nm, which comprised lipids (51.2%), protein (30.8%), and carbohydrates (7.9%). As indicated by the tests of free radical scavenging and ferric reducing capacities, the CNPs possessed remarkable antioxidant activity. Macrophages and enterocytes are essential for intestinal homeostasis. Therefore, RAW 264.7 and Caco-2 were applied to establish an oxidative stress model to investigate the antioxidant characteristics of the CNPs. The results showed that the CNPs from duck soup could be engulfed by these two cell lines, and could significantly alleviate 2,2'-Azobis(2-methylpropionamidine) dihydrochloride (AAPH)-induced oxidative damage. It indicates that the intake of duck soup is beneficial for intestinal health. These data contribute to revealing the underlying functional mechanism of Chinese traditional duck soup and the development of food-derived functional components.

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.

Folate administration ameliorates neurobehavioral effects of prenatal ethanol exposure

Background: Prenatal ethanol exposure (PEE) induces heightened ethanol intake at adolescence in preclinical studies. Ethanol intake alters the absorption of folate, a methyl-group donor critical for numerous cellular functions. The prenatal administration of folate is, therefore, a promising approach to reduce the effects of PEE.Objectives: Experiment 1 determined if prenatal folate modulated the effects of PEE on ethanol intake, anxiety-like response, and exploratory behaviors (Experiment 1) in Wistar rats. Experiment 2 assessed, in rats not given PEE, if postnatal folate reversed effects of ethanol exposure at postnatal days 28-42. Experiment 3 assessed if folate altered blood ethanol levels (BELs).Methods: Experiment 1 involved 242 (125 male) adolescent Wistar rats derived from dams given folate (20 mg/kg, gestational days - GD- 13-20) + ethanol (2.0 g/kg, GD 17-20), ethanol, or vehicle only at pregnancy. Experiment 2 involved 29 male adolescents administered vehicle or ethanol doses co-administered or not with folate. In Experiment 3 twelve adult females were tested for BELs after folate administration. These tests were applied: intake tests, light dark box (LDB), elevated plus maze, open field and concentric square field.Results: PEE heightened ethanol intake (η² ps = 0.06-07) and induced hyperactivity and a reduced latency to exit the white area of the LDB (η² ps = 0.12-17). These effects were partially inhibited by folate (p > .05). Rats exposed to ethanol exposure at adolescence exhibited reduced motor activity (η² p = .17), regardless of folate treatment. Folate did not affect BELs.Conclusion: Folate administration should be considered as a preventive or acute treatment to attenuate the neurobehavioral effects of PEE.

Why Is Longevity Still a Scientific Mystery? Sirtuins-Past, Present and Future

The sirtuin system consists of seven highly conserved regulatory enzymes responsible for metabolism, antioxidant protection, and cell cycle regulation. The great interest in sirtuins is associated with the potential impact on life extension. This article summarizes the latest research on the activity of sirtuins and their role in the aging process. The effects of compounds that modulate the activity of sirtuins were discussed, and in numerous studies, their effectiveness was demonstrated. Attention was paid to the role of a caloric restriction and the risks associated with the influence of careless sirtuin modulation on the organism. It has been shown that low modulators' bioavailability/retention time is a crucial problem for optimal regulation of the studied pathways. Therefore, a detailed understanding of the modulator structure and potential reactivity with sirtuins in silico studies should precede in vitro and in vivo experiments. The latest achievements in nanobiotechnology make it possible to create promising molecules, but many of them remain in the sphere of plans and concepts. It seems that solving the mystery of longevity will have to wait for new scientific discoveries.

Effect of Alcohol Intake on Inflammatory Status and Prognosis in Cancer Patients

Purpose

To explore the effect of alcohol on the inflammatory status and prognosis of patients with malignancy.

Patients and Methods

The clinical data of patients with malignant tumor who were admitted to the First Hospital of Jilin University from November 2011 to December 2018 were collected including basic clinical information, anthropometric indicators, body composition analysis, and serological indicators. Univariate and multivariate Cox proportional hazards models were performed to find predictors of survival. A nomogram was generated to indicate the interrelationships between the variables in the prediction model and the extent to which alcohol consumption affects prognosis. The C-index and calibration curves were used to verify the predictive accuracy of the scoring system.

Results

A total of 2929 cancer patients were included in this study, of which 552 (18.8%) patients had alcohol consumption habits and 2377 (81.2%) patients had no alcohol history. Patients in the Alcohol group had significantly shorter overall survival (OS) than the Non-Alcohol group, and further sub-analysis indicated alcohol consumption was significantly associated with prognosis of advanced breast cancer (HR = 4.617, 95% CI 1.361–15.664, p=0.014), and early stage hepatocellular carcinoma (HCC) without viral hepatitis (HR = 8.933, 95% CI 1.444–55.275, p = 0.019). Multivariate Cox regression models also demonstrated that daily alcohol intake was a risk factor of survival benefits (HR = 1.256, 95% CI 1.016–1.554, p = 0.036). Finally, a nomogram was constructed and the c-index of this scoring system is 0.751. The 3- and 5-year calibration curves of the model show a high agreement between the predicted probability and the actual observed survival rate.

Conclusion

Alcohol intake was demonstrated associates with patient outcomes. A human component-prognosis scoring system was established to predict the survival benefits of cancer patients.

The Putative Role of Astaxanthin in Neuroinflammation Modulation: Mechanisms and Therapeutic Potential

Neuroinflammation is a protective mechanism against insults from exogenous pathogens and endogenous cellular debris and is essential for reestablishing homeostasis in the brain. However, excessive prolonged neuroinflammation inevitably leads to lesions and disease. The use of natural compounds targeting pathways involved in neuroinflammation remains a promising strategy for treating different neurological and neurodegenerative diseases. Astaxanthin, a natural xanthophyll carotenoid, is a well known antioxidant. Mounting evidence has revealed that astaxanthin is neuroprotective and has therapeutic potential by inhibiting neuroinflammation, however, its functional roles and underlying mechanisms in modulating neuroinflammation have not been systematically summarized. Hence, this review summarizes recent progress in this field and provides an update on the medical value of astaxanthin. Astaxanthin modulates neuroinflammation by alleviating oxidative stress, reducing the production of neuroinflammatory factors, inhibiting peripheral inflammation and maintaining the integrity of the blood-brain barrier. Mechanistically, astaxanthin scavenges radicals, triggers the Nrf2-induced activation of the antioxidant system, and suppresses the activation of the NF-κB and mitogen-activated protein kinase pathways. With its good biosafety and high bioavailability, astaxanthin has strong potential for modulating neuroinflammation, although some outstanding issues still require further investigation.

Integrated metabolism and epigenetic modifications in the macrophages of mice in responses to cold stress

The negative effects of low temperature can readily induce a variety of diseases. We sought to understand the reasons why cold stress induces disease by studying the mechanisms of fine-tuning in macrophages following cold exposure. We found that cold stress triggers increased macrophage activation accompanied by metabolic reprogramming of aerobic glycolysis. The discovery, by genome-wide RNA sequencing, of defective mitochondria in mice macrophages following cold exposure indicated that mitochondrial defects may contribute to this process. In addition, changes in metabolism drive the differentiation of macrophages by affecting histone modifications. Finally, we showed that histone acetylation and lactylation are modulators of macrophage differentiation following cold exposure. Collectively, metabolism-related epigenetic modifications are essential for the differentiation of macrophages in cold-stressed mice, and the regulation of metabolism may be crucial for alleviating the harm induced by cold stress.

Emerging roles of Sirtuins in alleviating alcoholic liver Disease: A comprehensive review

Sirtuins (SIRTs), a NAD⁺ family of dependent deacetylases, are involved in the regulation of various human diseases. Recently, accumulating evidence has uncovered number of substrates and crucial roles of SIRTs in the pathogenesis of alcoholic liver disease (ALD). However, systematic reports are still lacking, so this review provides a comprehensive profile of the crucial physiological functions of SIRTs and its role in attenuating ALD, including alcoholic liver steatosis, steatohepatitis, and fibrosis. SIRTs play beneficial roles in energy/lipid metabolism, oxidative stress, inflammatory response, mitochondrial homeostasis, autophagy and necroptosis of ALD via regulating multiple signaling transduction pathways such as AMPK, LKB1, SREBP1, Lipin1, PGC-1α, PPARα/γ, FoxO1/3a, Nrf2/p62, mTOR, TFEB, RIPK1/3, HMGB1, NFATc4, NF-κB, TLR4, NLRP3, P2X7R, MAPK, TGF1β/Smads and Wnt/β-catenin. In addition, the mechanism and clinical application of natural/ synthetic SIRTs agonists in ALD are summarized, which provide a new idea for the treatment of ALD and basic foundation for further studies into target drugs.

Anti-Inflammatory Effects of (9Z,11E)-13-Oxooctadeca-9,11-dienoic Acid (13-KODE) Derived from Salicornia herbacea L. on Lipopolysaccharide-Stimulated Murine Macrophage via NF-kB and MAPK Inhibition and Nrf2/HO-1 Signaling Activation

Glasswort (Salicornia herbacea L.) is a halophyte that exhibits antioxidant and antidiabetic effects. Only a few studies have been conducted on its antioxidant effects. Here, we isolated an antioxidant using an activity-based purification method, and the resulting compound was identified as (9Z,11E)-13-Oxooctadeca-9,11-dienoic acid (13-KODE). We investigated its ability to suppress inflammatory responses and the molecular mechanisms underlying these abilities using lipopolysaccharide-stimulated RAW 264.7 macrophage cells. We studied the anti-inflammatory effects of 13-KODE derived from S. herbacea L on RAW 264.7 macrophages. 13-KODE inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) production by suppressing inducible NO synthase and suppressed LPS-induced tumor necrosis factor and interleukin-1β expression in RAW 264.7 macrophages. LPS-mediated nuclear localization of NF-κB and mitogen-activated protein kinase activation were inhibited by 13-KODE. 13-KODE significantly reduced LPS-induced production of reactive oxygen species and increased the expression of nuclear factor erythroid-2 like 2 (Nfe2I2) and heme oxygenase 1. Overall, our results indicate that 13-KODE may have potential for treating inflammation.

Glycogen-based pH and redox sensitive nanoparticles with ginsenoside Rh2 for effective treatment of ulcerative colitis

The purpose of this study is to construct a pH and redox sensitive nanoparticle to effectively deliver ginsenoside Rh₂ for the treatment of ulcerative colitis (UC). Herein, glycogen was modified by urocanic acid and α-lipoic acid (α-LA) to obtain an amphiphilic polymer (LA-UaGly). Such polymer LA-UaGly could self-assemble to form nanoparticles (Blank NPs) in water with excellent stability, which could also successfully encapsulated ginsenoside Rh₂ to form Rh₂ nanoparticles (Rh₂ NPs) with encapsulation efficiency of 74.36 ± 0.34%. DLS analysis indicated Rh₂ NPs were spherical with a particle size of 128.9 ± 0.3 nm. As expected, Rh₂ NPs exhibited typical pH and redox dual response release behaviour as well as the excellent in vivo safety. In vitro tests showed that Rh₂ NPs could effectively internalize and release Rh₂ into RAW264.7 cells, and protect cells from apoptosis (p < 0.05). More interestingly, Rh₂ NPs exhibited strong anti-inflammatory activity via significantly inhibiting the overproduction of nitric oxide (NO) and inflammatory cytokines (TNF-α, IL-1β and IL-6) (p < 0.05). In vivo experiments suggested that Rh₂ NPs significantly ameliorated the weight loss, colon length, disease activity index (DAI) score, and myeloperoxidase (MPO) activity in mice caused by dextran sulfate sodium salt (DSS) (p < 0.05). Simultaneously, pathological analysis proved that Rh₂ NPs could significantly reduce histological damage and inflammatory infiltration in mice. Rh₂ NPs could also effectively regulate the intestinal flora of mice by improving the species uniformity and abundance of the intestinal flora of mice and restoring the species diversity of the intestinal flora. In addition, both in vivo and in vitro experiments proved that Rh₂ NPs had stronger anti-inflammatory activity than Rh₂. This study provides a promising strategy for the effective treatment of UC.

Mangiferin inhibits hypoxia/reoxygenation-induced alveolar epithelial cell injury via the SIRT1/AMPK signaling pathway

Lung ischemia-reperfusion injury (LIRI) is one of the complications that can occur after lung transplantation and may lead to morbidity and mortality. Mangiferin (MAF) is a naturally occurring glucosyl xanthone that has been documented to possess anti-inflammatory, immunomodulatory and potent antioxidant effects. The purpose of the present study was to investigate the effect of MAF on LIRI using a hypoxia-reoxygenation (H/R) cell model. In the present study, the viability of lung alveolar epithelial cells (A549) and H/R-A549 were detected by MTT assay. ELISA was used to evaluate the expression levels of IL-6 and IL-1β. TUNEL assay and western blotting were used to evaluate the apoptosis. In addition, H/R-A549 cells were treated with sirtinol, which is known inhibitor of sirtuin 1 (SIRT1) activity, to determine the effects of MAF on proteins associated with the SIRT1/5'AMP-activate protein kinase (AMPK) signaling pathway using western blotting. The results showed that 20 µM MAF exerted a protective effect on A549 cells against H/R mediating no clear cytotoxic effects. In terms of inflammation, MAF reduced IL-6, IL-1β, cyclooxygenase-2 and inducible nitric oxide synthase expression, which was accompanied by activation of the SIRT1/AMPK signaling pathway. In addition, compared with those in the group treated with sirtinol, expression of SIRT1, Bcl-2 and AMPK activity were elevated in MAF-treated H/R-A549 cells, whereas the expression of Bax, cleaved caspase-3 and cleaved caspase-9 was suppressed. TUNEL analysis of H/R-A549 cells treated with MAF in combination with sirtinol revealed that treatment with sirtinol blocked the SIRT1/AMPK signaling pathway and increased the apoptosis rate compared with the MAF group. Taken together, results of the present study revealed that MAF could inhibit lung H/R cell injury through the SIRT1/AMPK signaling pathway.

Anti-Inflammatory and Anticancer Effects of Microalgal Carotenoids

Acute inflammation is a key component of the immune system’s response to pathogens, toxic agents, or tissue injury, involving the stimulation of defense mechanisms aimed to removing pathogenic factors and restoring tissue homeostasis. However, uncontrolled acute inflammatory response may lead to chronic inflammation, which is involved in the development of many diseases, including cancer. Nowadays, the need to find new potential therapeutic compounds has raised the worldwide scientific interest to study the marine environment. Specifically, microalgae are considered rich sources of bioactive molecules, such as carotenoids, which are natural isoprenoid pigments with important beneficial effects for health due to their biological activities. Carotenoids are essential nutrients for mammals, but they are unable to synthesize them; instead, a dietary intake of these compounds is required. Carotenoids are classified as carotenes (hydrocarbon carotenoids), such as α- and β-carotene, and xanthophylls (oxygenate derivatives) including zeaxanthin, astaxanthin, fucoxanthin, lutein, α- and β-cryptoxanthin, and canthaxanthin. This review summarizes the present up-to-date knowledge of the anti-inflammatory and anticancer activities of microalgal carotenoids both in vitro and in vivo, as well as the latest status of human studies for their potential use in prevention and treatment of inflammatory diseases and cancer.

A mouse model of the regression of alcoholic hepatitis: Monitoring the regression of hepatic steatosis, inflammation, oxidative stress, and NAD+ metabolism upon alcohol withdrawal

This study aimed to develop a well-characterized mouse model of alcoholic hepatitis (AH) regression. Male C57BL/6J mice were fed a Lieber-DeCarli (LD) control diet or LD containing 5% ethanol for ten days followed by one binge, which is the chronic-binge model of AH developed by the National Institute on Alcohol Abuse and Alcoholism. To determine AH regression, mice previously exposed to ethanol were put on LD control diet and metabolic and inflammatory features were monitored weekly for three weeks. Serum alcohol, total cholesterol, and alanine transaminase levels were increased in ethanol-fed mice, which declined to those of no ethanol controls within one and three weeks after ethanol withdrawal, respectively. Serum malondialdehyde was increased with ethanol feeding, but it was restored to no ethanol control levels within one week. Ethanol-induced changes in the hepatic expression of genes involved in lipogenesis, fatty acid oxidation, ethanol metabolism, and antioxidant response were restored to those of no ethanol controls after 3 weeks of ethanol withdrawal. Also, ethanol-induced hepatic inflammation was gradually decreased during the 3 weeks of ethanol withdrawal. Hepatic nicotinamide adenine dinucleotide (NAD⁺) levels and the expression of enzymes involved in the NAD⁺ salvage pathway were decreased by ethanol feeding, which was mitigated after ethanol withdrawal. Ethanol significantly lowered hepatic sirtuin 1 expression, but its levels were restored with ethanol cessation. This study established a mouse model of AH regression, which can be used as a preclinical model to study the potential of dietary bioactives or therapeutic agents on AH regression.

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.

Melanoidins, extracted from Chinese traditional vinegar powder, inhibit alcohol-induced inflammation and oxidative stress in macrophages via activation of SIRT1 and SIRT3

Alcohol induces inflammation and oxidative stress with the dysregulation of proinflammatory cytokines, which are implicated in the pathogenesis of alcoholic liver injury. Melanoidins are known to exert an antioxidant effect, however, their function in inhibiting alcohol-induced inflammation is unclear. In this study, we examined the role of melanoidins from Chinese traditional vinegar powder in terms of their anti-inflammatory and antioxidant properties in RAW 264.7 macrophages and elucidated their mechanisms of function. In macrophages, melanoidins significantly suppress the mRNA expression of interleukin (Il)-6, Il-1β and tumor necrosis factor α (Tnf-α) with a concomitant inhibitory effect on IL-1β, IL-6 and TNFα secretion, which are increased by ethanol. In addition, ethanol significantly increases the cellular reactive oxygen species (ROS) levels and the expression of cytochrome β-245 and beta polypeptide (Cybb), which are repressed by melanoidins to basal level. However, the expression of genes related to oxidative stress significantly decreases in response to ethanol, while it is significantly increased by melanoidins. Importantly, treatment with ethanol led to significant decreases in SIRT1 and SIRT3 transcription, translation, and activation, as well as the nicotinamide adenine dinucleotide (NAD⁺) levels. Interestingly, all the decreases were markedly attenuated by melanoidins. Ethanol promoted the expression of proinflammatory genes, whereas coincubation with resveratrol (a potent SIRT agonist) inhibited this effect. Conversely, the addition of sirtinol (a known SIRT inhibitor) augmented the proinflammatory gene expression. Taken together, our findings suggest that melanoidins exert anti-inflammatory and antioxidant functions via abolishing decreases in SIRT1 and SIRT3 expression and cellular NAD⁺ levels in ethanol-induced macrophages and may serve as a new therapeutic agent for the prevention of alcohol-induced cell damage.

The loss of histone deacetylase 4 in macrophages exacerbates hepatic and adipose tissue inflammation in male but not in female mice with diet-induced non-alcoholic steatohepatitis

Epigenetic regulation in macrophages plays a crucial role in the inflammatory response of cells. We investigated the role of macrophage histone deacetylase 4 (HDAC4) in diet-induced obesity and non-alcoholic steatohepatitis using macrophage-specific Hdac4 knockout mice (Hdac4^MKO ). Hdac4 floxed control (Hdac4^fl/fl ) and Hdac4^MKO mice were fed a regular chow diet or an obesogenic high-fat/high-sucrose/high-cholesterol (HF/HS/HC) diet for 12 weeks. The loss of macrophage Hdac4, compared with Hdac4^fl/fl control, aggravated the diet-induced inflammation in the liver and white adipose tissue only in male mice. Splenic monocytes isolated from male mice fed the HF/HS/HC diet showed increased lipopolysaccharide (LPS) sensitivity and decreased Ly6C-/Ly6C+ ratios in male Hdac4^MKO mice, but not in females. Bone marrow-derived macrophages (BMMs) from male Hdac4^MKO mice had a lesser efferocytotic capacity but higher proinflammatory gene expression upon LPS stimulation than male Hdac4^fl/fl mice. However, female Hdac4^MKO BMMs exhibited the opposite responses. The induction of estrogen receptor α (ERα, Esr1) expression by LPS was less in male but more in female Hdac4^MKO BMMs than Hdac4^fl/fl BMMs. Moreover, overexpression of human HDAC4 decreased basal expression of Esr1 and abolished its induction by LPS. Inhibition of ERα increased Hdac4 with induction of inflammatory genes, whereas activation of ERα decreased Hdac4 with reduction of inflammatory genes in male and female Hdac4^fl/fl BMMs treated with LPS. However, regardless of the inhibition or activation of ERα, proinflammatory genes were induced by LPS more in male Hdac4^MKO BMMs than Hdac4^fl/fl cells, whereas cells in females showed opposite responses. In conclusion, this study suggests that the lack of macrophage Hdac4 aggravates hepatic and white adipose inflammation in male mice with diet-induced obesity and non-alcoholic steatohepatitis, and not in female mice. HDAC4 and ERα appear to counteract each other, but ERα may not be a major player in sex-dependent inflammatory responses in macrophages deficient in HDAC4. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Preparation, characterization, antioxidant and anti-inflammatory activities of acid-soluble pectin from okra (Abelmoschus esculentus L.)

Currently, there are few studies on acid-soluble pectin from okra, especially in biological activity for antioxidant and anti-inflammatory. In this study, the antioxidant properties of acid-soluble okra pectin components and their anti-inflammatory were explored. Firstly, two acid-soluble okra pectic fractions, namely crude acid-soluble okra pectin (CAOP) and acid-soluble okra pectin (AOP), were obtained and exhibited structural and compositional variation. The two pectic fractions contained a low degree of esterification (42.0-46.5%) and a relatively high uronic acid content (31.6-37.3%). AOP was composed of galacturonic acid (79.1 mol/%), galactose (4.3 mol/%), rhamnose (14.5 mol/%) and xylose (2.1 mol/%), and the molecular weight was 92.8 kDa. Morphological and thermal properties of acid-soluble okra pectin components were also investigated. Compared to CAOP, AOP expressed better antioxidant activity, and suppressed the NO production in LPS-induced RAW 264.7 macrophages. All the above results indicated that AOP had the potential to act as a natural antioxidant or a functional anti-inflammatory food, which would broaden the development and utilization of okra resources.

Inhibition of alcohol-induced inflammation and oxidative stress by astaxanthin is mediated by its opposite actions in the regulation of sirtuin 1 and histone deacetylase 4 in macrophages

We previously demonstrated that astaxanthin (ASTX), a xanthophyll carotenoid, repressed ethanol-induced inflammation and oxidative stress in macrophages. We explored the role of sirtuin 1 (SIRT1) and histone deacetylase 4 (HDAC4) in the inhibitory effect of ASTX on inflammation and oxidative stress in macrophages exposed to ethanol. Ethanol decreased mRNA and protein of SIRT1 while increasing those of HDAC4, which was attenuated by ASTX in RAW 264.7 macrophages and mouse bone marrow-derived macrophages (BMDMs). Inhibition of SIRT1 expression or activity augmented ethanol-induced Hdac4 expression, but SIRT1 activation elicited the opposite effect. Consistently, Hdac4 knockdown increased Sirt1 expression with decreases in ethanol-induced inflammatory gene expression, but its overexpression resulted in the opposite effects. Furthermore, BMDMs from mice with macrophage specific-deletion of Hdac4 (Hdac4^MKO) showed significant decreases in ethanol-induced inflammatory genes and ROS accumulation but an increase in Sirt1 expression. Macrophage specific deletion of Hdac4 or ASTX abolished the changes in genes for mitochondrial biogenesis and glycolysis by ethanol. Ethanol increased mitochondrial respiration, ATP production, and proton leak, but decreased maximal respiration and spare respiratory capacity, all of which were abolished by ASTX in RAW 264.7 macrophages. The ethanol-induced alterations in mitochondrial respiration were abrogated in Hdac4^MKO BMDMs. In conclusion, the anti-inflammatory and antioxidant properties of ASTX in ethanol-treated macrophages may be mediated, at least partly, by its opposite effect on SIRT1 and HDAC4 to empower SIRT1 to counteract ethanol-induced activation of HDAC4.