Crosstalk between Sirtuins and Nrf2: SIRT1 activators as emerging treatment for diabetic neuropathy

SIRT6 Overexpression Enhances Diabetic Foot Ulcer Healing via Nrf2 Pathway Activation

Sirtuin-6 (SIRT6) has a pivotal role in a wide array of cellular biological functions and is linked to the progression of various diseases. Previous findings have identified SIRT6 as a protective modulator against numerous diabetic complications. However, whether SIRT6 exerts a protective role in diabetic foot ulcer (DFU) remains unstudied. This work established a rat model of DFU and evaluated the possible role of SIRT6 in mediating the wound healing in DFU. Marked reductions in SIRT6 levels were observed in wound samples from DFU patients and rats. Increasing SIRT6 expression in wound tissues remarkably decreased wound area, accelerated epithelialisation, increased collagen deposition and improved angiogenesis. Moreover, up-modulation of SIRT6 relieved the oxidative stress and inflammation in DFU rats. The increase of SIRT6 in cultured vascular endothelial cells restrained cell apoptosis, oxidative stress and inflammation elicited by high glucose (HG). HG-impaired migration capacity and angiogenesis of vascular endothelial cells was also recovered by increasing SIRT6 expression. Mechanism research revealed that SIRT6 overexpression reinforced the activation of the Nrf2 pathway in wound tissues of DFU rats and HG-exposed vascular endothelial cells. Pharmacological suppression of Nrf2 reversed the protective effect of SIRT6 overexpression on HG-triggered endothelial dysfunction. The findings of this work indicate that the positive role of SIRT6 in DFU wound healing is related to Nrf2 activation which contributes to the suppression of oxidative stress and inflammation and the improvement of angiogenesis in vascular endothelial cells. This study highlights the previously unaddressed role of SIRT6 in DFU wound healing, providing novel insights into its protective functions. The findings hold significant clinical value by identifying SIRT6 as a promising therapeutic target for improving DFU wound healing.

Swietenolide inhibits the TXNIP/NLRP3 pathways via Nrf2 activation to ameliorate cognitive dysfunction in diabetic mice

Oxidative stress and inflammation play important roles in diabetic-associated cognitive dysfunction (DACD). Swietenolide (Std), isolated from the fruit of Swietenia macrophylla King, exhibits various potent pharmacological activities, including antioxidant, anti-inflammatory, and anti-tumor properties. However, the effects of Std on DACD remains unexplored. We utilized diabetic db/db mice and the hippocampal cell line HT22 to evaluate the effects and underlying molecular mechanisms of Std on DACD. Molecular docking study, western blotting, immunohistochemistry, and enzyme-linked immunosorbent assay analyses were conducted to elucidate the molecular mechanisms involved. We found that Std significantly improved cognitive dysfunction in diabetic mice and increased cell viability in HT22 cells under high glucose condition. The reduction in superoxide dismutase (SOD) enzamy activity and glutathione (GSH) level, along with an increase in malondialdehyde (MDA) induced by high glucose in hippocampus, were reversed by Std treatment. Furthermore, Std effectively diminished the levels of proinflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). Importantly, Std markedly activated the Nrf2 pathway to inhibit the thioredoxin-interacting protein/NOD-like receptor protein 3 (TXNIP/NLRP3) pathways. However, the neuroprotective effect of Std was significantly weakened by Nrf2 inhibitor ML385. These results indicate that Std provides substantial protection against high glucose-induced hippocampal injury by inhibiting the TXNIP/NLRP3 pathways dependent on Nrf2, which may serve as a promising agent for attenuating DACD.

Association between compound dietary antioxidant index and all-cause and cancer mortality in patients with chronic obstructive pulmonary disease: results from NHANES 1999-2018

Objective

Chronic obstructive pulmonary disease (COPD) is one of the most important causes of death in the world, and its core is chronic inflammation. Antioxidants play a positive role in the onset and prognosis of chronic respiratory diseases. In maintaining human health, the composite dietary antioxidant index (CDAI) plays an important function. Therefore, the purpose of the current study was to investigate the relationship between CDAI and all-cause and cancer mortality in individuals with COPD.

Methods

A prospective cohort study was conducted by investigating NHANES data between 1999-2018. The study included people who satisfied the inclusion and exclusion criteria. In this study, the association between CDAI and all-cause and cancer mortality was investigated using weighted Cox regression. The relationship between them is illustrated by drawing constrained cubic spline curves (RCS). Finally, subgroup analysis is used to further verify.

Results

The study included 1,534 participants. CDAI was associated with COPD patients mortality, and after adjusting for multiple factors, we observed a 5% reduction in the risk of all-cause mortality (HR = 0.95, 95% CI: 0.92-0.97) was associated with a 9% lower risk of cancer mortality for each one-unit increase in CDAI (HR = 0.91, 95% CI: 0.85-0.98). After adjusting for multiple factors, high CDAI was associated with a reduced risk of mortality, with patients in the high CDAI group having 35% lower all-cause mortality than those in the low CDAI group (HR = 0.65, 95% CI: 0.50-0.85), the high CDAI group had a 61% lower risk of cancer mortality (HR = 0.39,95% CI: 0.23-0.68). Subgroup analysis and sensitivity analysis showed a consistent association between CDAI and COPD mortality.

Conclusion

Our study highlights the inverse association between CDAI and all-cause and cancer mortality in patients with COPD. Further prospective studies are needed to confirm the role of CDAI in mortality risk in patients with COPD.

Electroacupuncture alleviates diabetic peripheral neuropathy through modulating mitochondrial biogenesis and suppressing oxidative stress

BACKGROUND

Peripheral neuropathy caused by diabetes is closely related to the vicious cycle of oxidative stress and mitochondrial dysfunction resulting from metabolic abnormalities. The effects mediated by the silent information regulator type 2 homolog-1 (SIRT1)/peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) axis present new opportunities for the treatment of type 2 diabetic peripheral neuropathy (T2DPN), potentially breaking this harmful cycle.

AIM

To validate the effectiveness of electroacupuncture (EA) in the treatment of T2DPN and investigate its potential mechanism based on the SIRT1/PGC-1α axis.

METHODS

The effects of EA were evaluated through assessments of metabolic changes, morphological observations, and functional examinations of the sciatic nerve, along with measurements of inflammation and oxidative stress. Proteins related to the SIRT1/PGC-1α axis, involved in the regulation of mitochondrial biogenesis and antioxidative stress, were detected in the sciatic nerve using Western blotting to explain the underlying mechanism. A counterevidence group was created by injecting a SIRT1 inhibitor during EA intervention to support the hypothesis.

RESULTS

In addition to diabetes-related metabolic changes, T2DPN rats showed significant reductions in pain threshold after 9 weeks, suggesting abnormal peripheral nerve function. EA treatment partially restored metabolic control and reduced nerve damage in T2DPN rats. The SIRT1/PGC-1α axis, which was downregulated in the model group, was upregulated by EA intervention. The endogenous antioxidant system related to the SIRT1/PGC-1α axis, previously inhibited in diabetic rats, was reactivated. A similar trend was observed in inflammatory markers. When SIRT1 was inhibited in diabetic rats, these beneficial effects were abolished.

CONCLUSION

EA can alleviate the symptoms of T2DNP in experimental rats, and its effects may be related to the mitochondrial biogenesis and endogenous antioxidant system mediated by the SIRT1/PGC-1α axis.

Acyclic sesquiterpenes nerolidol and farnesol: mechanistic insights into their neuroprotective potential

Sesquiterpenes are a class of organic compounds found in plants, fungi, and some insects. They are characterized by the presence of three isoprene units, resulting in a molecular formula that typically contains 15 carbon atoms (C₁₅H₂₄). Nerolidol and farnesol are both sesquiterpene alcohols present in the essential oils of numerous plants. They have drawn attention due to their potential neuroprotective properties. Nerolidol and farnesol are structural isomers, specifically geometric isomers, haring the same molecular formula (C₁₅H₂₄O) but differing in the spatial arrangement of their atoms. This variation in structure may contribute to their distinct biological activities. Scientific evidence suggests that nerolidol and farnesol exhibit antioxidant and anti-inflammatory characteristics which are crucial for neuroprotection. Nerolidol has been specifically noted for its ability to alleviate conditions such as Alzheimer's disease, Parkinson's disease, encephalomyelitis, depression, and anxiety by modulating inflammatory and oxidative stress pathways. Moreover, research indicates that both nerolidol and farnesol may modulate the Nrf-2/HO-1 antioxidant signaling pathway to mitigate oxidative stress-induced neurological damage. Activation of Nrf-2/HO-1 signaling cascade promotes cell survival and enhances the brain's ability to resist various insults. Nerolidol has also been reported to alleviate neuroinflammation by inhibiting the TLR-4/NF-κB and COX-2/NF-κB inflammatory signaling pathway. Besides, this nerolidol also modulates BDNF/TrkB/CREB signaling pathway to improve neuronal health. To date, limited research has delved into the anti-inflammatory properties of farnesol concerning neurodegenerative diseases. Further investigation is warranted to comprehensively elucidate the mechanisms underlying its action and potential therapeutic uses in neuroprotection. Initial observations indicate that farnesol exhibits promising prospects as a natural agent for safeguarding brain functions. Henceforth, drawing upon existing literature elucidating the neuroprotective attributes of nerolidol and farnesol, the current review endeavors to provide a detailed analysis of their mechanistic underpinnings in neuroprotection.

The enigmatic role of SIRT2 in the cardiovascular system: Deciphering its protective and detrimental actions to unlock new avenues for therapeutic intervention

Cardiovascular diseases (CVDs) are leading causes of mortality throughout the world, and hence, there is a critical need to elucidate their molecular mechanisms. The Sirtuin (SIRT) family of NAD+-dependent enzymes has recently been shown to play a critical role in cardiovascular health and disease, and several SIRT isoforms, especially SIRT1 and SIRT3, have been amply investigated. However, the precise function of SIRT2 is only partially explored. Here, we review the current understanding of the involvement of SIRT2 in various cardiovascular pathologies, such as cardiac hypertrophy, ischemia-reperfusion injury, diabetic cardiomyopathy, and vascular dysfunction, with emphasis placed on the context-dependent protective or deleterious actions of SIRT2, including its wide array of catalytic activities which span beyond deacetylation. Furthermore, the review uncovers several unresolved research gaps for SIRT2 mechanisms by which SIRT2 modulates cardiac and vascular function during development and aging, thereby paving the way for the discovery of novel therapeutic targets as well as SIRT2-targeted interventions in the prevention and treatment of various cardiovascular diseases.

ADSCs-derived exosomes suppress macrophage ferroptosis via the SIRT1/NRF2 signaling axis to alleviate acute lung injury in sepsis

Acute lung injury being one of the earliest and most severe complications during sepsis and macrophages play a key role in this process. To investigate the regulatory effects and potential mechanisms of adipose mesenchymal stem cell derived-exosomes (ADSC-exo) on macrophages and septic mice, ADSCs-exo was administrated to both LPS-induced macrophage and cecal ligation and puncture (CLP) induced sepsis mice. ADSCs-exo was confirmed to inhibit M1 polarization of macrophages and to reduce excessive inflammation. The use of ADSCs-exo in CLP mice and in LPS-induced macrophages relieved oxidative stress, cellular damage, and acute lung injury. During this process, ADSCs-exo increased the nuclear translocation of Nrf2, significantly upregulating the activation of the antioxidant pathway Nrf2/HO-1. Concurrently, they enhanced the expression of SIRT1 in macrophages. Further SIRT1 interference experiments demonstrated that ADSCs-exo mitigated macrophage inflammatory responses and LPS-induced ferroptosis by upregulating SIRT1. In the LPS-induced macrophage model, after SIRT1 was interfered with, ADSCs-exo failed to upregulate the Nrf2/HO-1 signaling pathway, leading to enhanced ferroptosis. Finally, in a CLP sepsis mouse model with myeloid-specific SIRT1 knockout, ADSCs-exo was observed to reduce lung tissue injury, oxidative stress damage, and ferroptosis. Still, these beneficial effects were reversed due to the myeloid-specific knockout of SIRT1, while co-administration of a ferroptosis inhibitor rescued this situation, alleviating lung injury and significantly reducing tissue levels of oxidative stress. In conclusion, this study elucidated a novel potential therapeutic mechanism wherein ADSCs-exo upregulates the levels of SIRT1 in macrophages through a non-delivery approach.

The Role of SIRT1-BDNF Signaling Pathway in Fluoride-Induced Toxicity for Glial BV-2 Cells

Chronic fluorosis is often accompanied by neurological symptoms, leading to attention, memory and learning ability decline and causing tension, anxiety, depression, and other mental symptoms. In the present study, we analyzed the molecular mechanisms of SIRT1-BDNF regulation of PI3K-AKT, MAPK, and FOXO1A in F-treated BV2 cells. The cytotoxic effect of sodium fluoride (NaF) on BV2 cells was assessed using Cell Counting Kit-8 (CCK-8), crystal violet, and 5-ethynyl-2'-deoxyuridine (EdU) staining. Cell cycle progression and apoptosis were evaluated through flow cytometry and western blotting. Reactive oxygen species (ROS) levels, oxidative stress, and inflammatory markers were measured by ROS staining, microplate reader assays, and western blotting. The role of SIRT1 in fluoride-induced toxicity for glial cells was determined using the SIRT1 activator SRT1720. The experiments demonstrated that NaF was toxic to BV2 cells, inhibited their proliferative ability, halted their cell cycle progression, triggered cellular apoptosis, promoted cellular oxidative stress (detected by ROS, SOD, MDA, GSH-Px, T-AOC) and associated protein NQO-1 and HO-1, and elevated inflammatory mediator associated protein IL-1and IL-6 expression). The fluoride-exposed groups had reduced SIRT1, BDNF, TrkB, PI3K, AKT, and MAPK protein expression levels, and increased FOXO1A protein expression. SRT1720 mitigated the harmful effects of NaF, stimulated cell proliferation and cell cycle progression, decreased apoptosis, reduced oxidative stress and inflammatory factors, elevated SIRT1, BDNF, TrkB, PI3K, AKT, and MAPK protein levels, and suppressed FOXO1A protein expression. The results indicate that NaF potentially harms glial cells by suppressing SIRT1 activation, and SIRT1 significantly mitigated the damage. Furthermore, the SIRT1 signaling pathway might regulate the nerve damage caused by fluoride poisoning and may be a protective factor in treating fluoride-induced brain injury.

Sirtuin insights: bridging the gap between cellular processes and therapeutic applications

The greatest challenges that organisms face today are effective responses or detection of life-threatening environmental changes due to an obvious semblance of stress and metabolic fluctuations. These are associated with different pathological conditions among which cancer is most important. Sirtuins (SIRTs; NAD+-dependent enzymes) are versatile enzymes with diverse substrate preferences, cellular locations, crucial for cellular processes and pathological conditions. This article describes in detail the distinct roles of SIRT isoforms, unveiling their potential as either cancer promoters or suppressors and also explores how both natural and synthetic compounds influence the SIRT function, indicating promise for therapeutic applications. We also discussed the inhibitors/activators tailored to specific SIRTs, holding potential for diseases lacking effective treatments. It may uncover the lesser-studied SIRT isoforms (e.g., SIRT6, SIRT7) and their unique functions. This article also offers a comprehensive overview of SIRTs, linking them to a spectrum of diseases and highlighting their potential for targeted therapies, combination approaches, disease management, and personalized medicine. We aim to contribute to a transformative era in healthcare and innovative treatments by unraveling the intricate functions of SIRTs.

Natural products modulate phthalate-associated miRNAs and targets

Phthalates are widespread and commonly used plasticizers that lead to adverse health effects. Several natural products provide a protective effect against phthalates. Moreover, microRNAs (miRNAs) are regulated by natural products and phthalates. Therefore, miRNAs' impacts and potential targets may underlie the mechanism of phthalates. However, the relationship between phthalate-modulated miRNAs and phthalate protectors derived from natural products is poorly understood and requires further supporting information. In this paper, we review the adverse effects and potential targets of phthalates on reproductive systems as well as cancer and non-cancer responses. Information on natural products that attenuate the adverse effects of phthalates is retrieved through a search of Google Scholar and the miRDB database. Moreover, information on miRNAs that are upregulated or downregulated in response to phthalates is collected, along with their potential targets. The interplay between phthalate-modulated miRNAs and natural products is established. Overall, this review proposes a straightforward pathway showing how phthalates modulate different miRNAs and targets and cause adverse effects, which are partly attenuated by several natural products, thereby providing a direction for investigating the natural product-miRNA-target axis against phthalate-induced effects.

Pterostilbene, a Resveratrol Derivative, Improves Ovary Function by Upregulating Antioxidant Defenses in the Aging Chickens via Increased SIRT1/Nrf2 Expression

Oxidative stress is recognized as a prominent factor contributing to follicular atresia and ovarian aging, which leads to decreased laying performance in hens. Reducing oxidative stress can improve ovarian function and prolong the laying period in poultry. This study investigates the impact of Pterostilbene (PTS), a natural antioxidant, on ovarian oxidative stress in low-laying chickens. Thirty-six Hy-Line White laying chickens were evenly divided into four groups and fed diets containing varying doses of PTS for 15 consecutive days. The results showed that dietary supplementation with PTS significantly increased the laying rate, with the most effective group exhibiting a remarkable 42.7% increase. Furthermore, PTS significantly enhanced the antioxidant capacity of aging laying hens, as evidenced by increased levels of glutathione, glutathione peroxidase, superoxide dismutase, catalase, and total antioxidant capacity in the ovaries, livers, and serum. Subsequent experiments revealed decreased expressions of Bax, Caspase-3, and γ-H2AX, along with an increased expression of BCL-2 in the ovaries and livers of laying hens. PTS supplementation also positively affects fat metabolism by reducing abdominal fat accumulation and promoting fat transfer from the liver to the ovary. To elucidate the mechanism underlying the effects of PTS on ovarian function, a series of in vitro experiments were conducted. These in vitro experiments revealed that PTS pretreatment restored the antioxidant capacity of D-galactose-induced small white follicles by upregulating SIRT1/Nrf2 expression. This protective effect was inhibited by EX-527, a specific inhibitor of SIRT1. These findings suggest that the natural antioxidant PTS has the potential to regulate cell apoptosis and fat metabolism in laying chickens by ameliorating oxidative stress, thereby enhancing laying performance.

Current state of knowledge of triclosan (TCS)-dependent reactive oxygen species (ROS) production

Triclosan (TCS) is widely used in a number of industrial and personal care products. This molecule can induce reactive oxygen species (ROS) production in various cell types, which results in diverse types of cell responses. Therefore, the aim of the present study was to summarize the current state of knowledge of TCS-dependent ROS production and the influence of TCS on antioxidant enzymes and pathways. To date, the TCS mechanism of action has been widely investigated in non-mammalian organisms that may be exposed to contaminated water and soil, but there are also in vivo and in vitro studies on plants, algae, mammalians, and humans. This literature review has revealed that mammalian organisms are more resistant to TCS than non-mammalian organisms and, to obtain a toxic effect, the effective TCS dose must be significantly higher. The TCS-dependent increase in the ROS level causes damage to DNA, protein, and lipids, which together with general oxidative stress leads to cell apoptosis or necrosis and, in the case of cancer cells, faster oncogenesis and even initiation of oncogenic transformation in normal human cells. The review presents the direct and indirect TCS action through different receptor pathways.

Hepatoprotective Activity and Mechanisms of Prenylated Stilbenoids

Dietary prenylated stilbenoids, found in various food sources, offer multiple health benefits, including liver protection. However, the underlying mechanisms of hepatoprotection remain unclear. In this study, we synthesized 13 natural prenylated stilbenoids and examined their hepatoprotective activities, with silent mating type information regulation 2 homologue-1 (SIRT1) as the primary target for screening. Among all of the prenylated stilbenoids tested, 4-C-geranyl oxyresveratrol demonstrated superior performance. It activated SIRT1 activity more effectively than resveratrol, a well-known SIRT1 activator. To further investigate the mechanism of liver protection, two in vitro models were used: the palmitic acid-induced lipid accumulation model and the H2O2-induced apoptosis model. Our findings suggested that 4-C-geranyl oxyresveratrol mitigated lipid accumulation through the SIRT1-PGC1α pathway, reduced apoptosis via the SIRT1-p53-p21 pathway, and exerted antioxidant effects through the SIRT1-Nrf2 pathway. These findings provide new insights into the chemical basis of the health benefits of prenylated stilbenoids and their potential use as functional food additives.

The SIRT1/Nrf2 signaling pathway mediates the anti-pulmonary fibrosis effect of liquiritigenin

BACKGROUND

At present, the treatment options available for idiopathic pulmonary fibrosis are both limited and often come with severe side effects, emphasizing the pressing requirement for innovative therapeutic alternatives. Myofibroblasts, which hold a central role in pulmonary fibrosis, have a close association with the Smad signaling pathway induced by transforming growth factor-β1 (TGF-β1) and the transformation of myofibroblasts driven by oxidative stress. Liquiritigenin, an active compound extracted from the traditional Chinese herb licorice, boasts a wide array of biomedical properties, such as anti-fibrosis and anti-oxidation. The primary objective of this study was to examine the impact of liquiritigenin on bleomycin-induced pulmonary fibrosis in mice and the underlying mechanisms.

METHODS

The anti-pulmonary fibrosis and anti-oxidant effects of liquiritigenin in vivo were tested by HE staining, Masson staining, DHE staining and bio-chemical methods. In vitro, primary mouse lung fibroblasts were treated with TGF-β1 with or without liquiritigenin, the effects of liquiritigenin in inhibiting differentiation of myofibroblasts and facilitating the translocation of Nrf2 were valued using Quantitative real-time polymerase chain reaction (Q-PCR), western blotting and immunofluorescence. Nrf2 siRNA and SIRT1 siRNA were used to investigate the mechanism underlies liquiritigenin's effect in inhibiting myofibroblast differentiation.

RESULTS

Liquiritigenin displayed a dose-dependent reduction effect in bleomycin-induced fibrosis. In laboratory experiments, it was evident that liquiritigenin possessed the ability to enhance and activate sirtuin1 (SIRT1), thereby facilitating the nuclear translocation of Nrf2 and mitigating the oxidative stress-induced differentiation of primary mouse myofibroblasts. Moreover, our investigation unveiled that SIRT1 not only regulated myofibroblast differentiation via Nrf2-mediated antioxidant responses against oxidative stress but also revealed liquiritigenin's activation of SIRT1, enabling direct binding to Smad. This led to decreased phosphorylation of the Smad complex, constrained nuclear translocation, and suppressed acetylation of the Smad complex, ultimately curtailing the transcription of fibrotic factors. Validation in live subjects provided substantial evidence for the anti-fibrotic efficacy of liquiritigenin through the SIRT1/Nrf2 signaling pathway.

CONCLUSIONS

Our findings imply that targeting myofibroblast differentiation via the SIRT1/Nrf2 signaling pathway may constitute a pivotal strategy for liquiritigenin-based therapy against pulmonary fibrosis.

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.

Puerarin ameliorates metabolic dysfunction-associated fatty liver disease by inhibiting ferroptosis and inflammation

Metabolic dysfunction-associated fatty liver disease (MAFLD) is frequently linked to type 2 diabetes mellitus (T2DM), and both conditions exacerbate the progression of the other. However, there is currently no standardized treatment or drug for MAFLD. In this study, A MAFLD animal model through a high-fat diet (HFD) along with administration of streptozotocin (STZ), and palmitic acid (PA)-induced AML12 cells were treated by puerarin. The objective of this study was to assess the therapeutic effect of puerarin, a flavonoid substance that possesses various pharmacological properties, on MAFLD. The results showed that puerarin administration enhanced glucose tolerance and insulin sensitivity, while also mitigating liver dysfunction and hyperlipidemia in MAFLD mice. Moreover, puerarin attenuated oxidative stress levels and inflammation in the liver. Transmission electron microscopy and Western blot analysis indicated that puerarin inhibited ferroptosis in vivo. Further mechanistic investigations revealed that puerarin upregulated SIRT1 expression, increased nuclear factor erythroid 2-related factor 2 (Nrf2) protein levels, and facilitated translocation into the nucleus. The protective effect of puerarin on PA-induced AML12 cells was diminished by the utilization of EX-527 (a SIRT1 inhibitor) and Nrf2 siRNA. Overall, the results demonstrate that puerarin ameliorates MAFLD by suppressing ferroptosis and inflammation via the SIRT1/Nrf2 signaling pathway. The results emphasize the possible medicinal application of puerarin for managing MAFLD.

Saikosaponin A alleviates Staphylococcus aureus-induced mastitis in mice by inhibiting ferroptosis via SIRT1/Nrf2 pathway

Mastitis is a common and serious bacterial infection of the mammary gland. Saikosaponin A (SSA) is a triterpenoid saponin isolated from Bupleurum falcatum that has the ability to treat various diseases. However, little is known about the role of SSA in achieving mastitis remission. Here, we found that SSA alleviated Staphylococcus aureus (S. aureus)-induced mastitis by attenuating inflammation and maintaining blood-milk barrier integrity. Furthermore, S. aureus activated nuclear factor kappa B (NF-κB) pathway by upregulated p-p65 and p-IκB. S. aureus also induced ferroptosis in mammary gland in mice, mainly characterized by excessive iron accumulation, mitochondrial morphological changes and impaired antioxidant production. However, S. aureus-induced NF-κB activation and ferroptosis were prevented by SSA. Moreover, SAA could upregulate the expression of SIRT1, Nrf2, HO-1 and GPX4. And the inhibitory effects of SAA on inflammation and ferroptosis were reversed by SIRT1 inhibitor EX-527. In conclusion, SAA protected S. aureus-induced mastitis through suppressing inflammation and ferroptosis by activating SIRT1/Nrf2 pathway.

Sirtuin1 Mediates the Protective Effects of Echinacoside against Sepsis-Induced Acute Lung Injury via Regulating the NOX4-Nrf2 Axis

Currently, the treatment for sepsis-induced acute lung injury mainly involves mechanical ventilation with limited use of drugs, highlighting the urgent need for new therapeutic options. As a pivotal aspect of acute lung injury, the pathologic activation and apoptosis of endothelial cells related to oxidative stress play a crucial role in disease progression, with NOX4 and Nrf2 being important targets in regulating ROS production and clearance. Echinacoside, extracted from the traditional Chinese herbal plant Cistanche deserticola, possesses diverse biological activities. However, its role in sepsis-induced acute lung injury remains unexplored. Moreover, although some studies have demonstrated the regulation of NOX4 expression by SIRT1, the specific mechanisms are yet to be elucidated. Therefore, this study aimed to investigate the effects of echinacoside on sepsis-induced acute lung injury and oxidative stress in mice and to explore the intricate regulatory mechanism of SIRT1 on NOX4. We found that echinacoside inhibited sepsis-induced acute lung injury and oxidative stress while preserving endothelial function. In vitro experiments demonstrated that echinacoside activated SIRT1 and promoted its expression. The activated SIRT1 was competitively bound to p22 phox, inhibiting the activation of NOX4 and facilitating the ubiquitination and degradation of NOX4. Additionally, SIRT1 deacetylated Nrf2, promoting the downstream expression of antioxidant enzymes, thus enhancing the NOX4-Nrf2 axis and mitigating oxidative stress-induced endothelial cell pathologic activation and mitochondrial pathway apoptosis. The SIRT1-mediated anti-inflammatory and antioxidant effects of echinacoside were validated in vivo. Consequently, the SIRT1-regulated NOX4-Nrf2 axis may represent a crucial target for echinacoside in the treatment of sepsis-induced acute lung injury.

Nrf2-mediated therapeutic effects of dietary flavones in different diseases

Oxidative stress (OS) is a pathological status that occurs when the body's balance between oxidants and antioxidant defense systems is broken, which can promote the development of many diseases. Nrf2, a redox-sensitive transcription encoded by NFE2L2, is the master regulator of phase II antioxidant enzymes and cytoprotective genes. In this context, Nrf2/ARE signaling can be a compelling target against OS-induced diseases. Recently, natural Nrf2/ARE regulators like dietary flavones have shown therapeutic potential in various acute and chronic diseases such as diabetes, neurodegenerative diseases, ischemia-reperfusion injury, and cancer. In this review, we aim to summarize nrf2-mediated protective effects of flavones in different conditions. Firstly, we retrospected the mechanisms of how flavones regulate the Nrf2/ARE pathway and introduced the mediator role Nrf2 plays in inflammation and apoptosis. Then we review the evidence that flavones modulated Nrf2/ARE pathway to prevent diseases in experimental models. Based on these literature, we found that flavones could regulate Nrf2 expression by mechanisms below: 1) dissociating the binding between Nrf2 and Keap1 via PKC-mediated Nrf2 phosphorylation and P62-mediated Keap1 autophagic degradation; 2) regulating Nrf2 nuclear translocation by various kinases like AMPK, MAPKs, Fyn; 3) decreasing Nrf2 ubiquitination and degradation via activating sirt1 and PI3K/AKT-mediated GSK3 inhibition; and 4) epigenetic alternation of Nrf2 such as demethylation at the promoter region and histone acetylation. In conclusion, flavones targeting Nrf2 can be promising therapeutic agents for various OS-related disorders. However, there is a lack of investigations on human subjects, and new drug delivery systems to improve flavones' treatment efficiency still need to be developed.

Dietary Supplementation with a Cocoa-Carob Blend Modulates Gut Microbiota and Prevents Intestinal Oxidative Stress and Barrier Dysfunction in Zucker Diabetic Rats

We have recently developed a cocoa-carob blend (CCB) rich in polyphenols with antidiabetic properties. In this study, we investigated whether its benefits could be related to gut health and gut microbiota (GM) composition and the likely phenolic metabolites involved. Zucker diabetic fatty rats were fed on a standard or a CCB-rich diet for 12 weeks. Intestinal barrier structure and oxidative and inflammatory biomarkers were analyzed in colonic samples. GM composition and phenolic metabolites were evaluated from feces. The results show that CCB improved mucin and tight-junction proteins and counteracted gut oxidative stress and inflammation by regulating sirtuin-1 and nuclear factor erythroid 2-related factor 2 (Nrf2) levels. CCB also modulated the composition of the GM, showing increases in Akkermansia and Bacteroides and decreases in Ruminococcus genera. Correlation analysis strengthened the associations between these genera and improved pathological variables in diabetic animals. Moreover, 12 phenolic metabolites were identified in CCB feces, being2,3-dihydroxybenzoic and 3,4,5-trihydroxybenzoic acids significantly associated with increased levels of Akkermansia and Oscillospira genera. Our findings support the potential use of CCB to prevent intestinal damage and dysbiosis in T2D, which would help to delay the progression of this pathology.

Activation of Nrf2 pathway as a protective mechanism against oxidative stress-induced diseases: Potential of astaxanthin

Astaxanthin, a red-orange liposoluble carotenoid, has been the centre of considerable attention in recent years for its numerous biological activities, notably its potent antioxidant activity. It is reported that astaxanthin elicits these biological activities via a number of cellular pathways. The Nrf2/Keap1 pathway is a major regulator of the antioxidant defence system of cells; it modulates the expression of a plethora of genes related to redox homeostasis as well as cellular detoxification. The pathway has received lots of attention as a prospective therapeutic target for diseases related to oxidative stress and aging. Several reports have shown that the pathway is inducible by many natural compounds. This present work reviews the Nrf2/Keap1 pathway, its regulation and involvement in diseases, provides a brief overview of naturally occurring compounds as activators of the pathway as well as discusses the effect of astaxanthin on the pathway.

Agomelatine, a Melatonin-Derived Drug, as a New Strategy for the Treatment of Colorectal Cancer

The potential use of agomelatine as an alternative treatment for colorectal cancer is evaluated in this work. The effect of agomelatine was studied in an in vitro model using two cell lines with different p53 statuses (HCT-116, wild-type p53, and HCT-116 p53 null) and an in vivo xenograft model. The inhibitory effects of agomelatine and melatonin were stronger in the cells harboring the wild-type p53, although in both cell lines, the effect of agomelatine was greater than that of the melatonin. In vivo, only agomelatine was able to reduce the volumes of tumors generated by the HCT-116-p53-null cells. Both treatments induced changes in the rhythmicity of the circadian-clock genes in vitro, albeit with some differences. Agomelatine and melatonin regulated the rhythmicity of Per1-3, Cry1, Sirt1, and Prx1 in the HCT-116 cells. In these cells, agomelatine also regulated Bmal1 and Nr1d2, while melatonin changed the rhythmicity of Clock. In the HCT-116-p53-null cells, agomelatine regulated Per1-3, Cry1, Clock, Nr1d2, Sirt1, and Prx1; however, melatonin only induced changes in Clock, Bmal1, and Sirt1. The differences found in the regulation of the clock genes may explain the greater oncostatic effect of agomelatine in CRC.

Oxidative Stress and Epigenetics: miRNA Involvement in Rare Autoimmune Diseases

Autoimmune diseases (ADs) such as Sjögren’s syndrome, Kawasaki disease, and systemic sclerosis are characterized by chronic inflammation, oxidative stress, and autoantibodies, which cause joint tissue damage, vascular injury, fibrosis, and debilitation. Epigenetics participate in immune cell proliferation and differentiation, which regulates the development and function of the immune system, and ultimately interacts with other tissues. Indeed, overlapping of certain clinical features between ADs indicate that numerous immunologic-related mechanisms may directly participate in the onset and progression of these diseases. Despite the increasing number of studies that have attempted to elucidate the relationship between miRNAs and oxidative stress, autoimmune disorders and oxidative stress, and inflammation and miRNAs, an overall picture of the complex regulation of these three actors in the pathogenesis of ADs has yet to be formed. This review aims to shed light from a critical perspective on the key AD-related mechanisms by explaining the intricate regulatory ROS/miRNA/inflammation axis and the phenotypic features of these rare autoimmune diseases. The inflamma-miRs miR-155 and miR-146, and the redox-sensitive miR miR-223 have relevant roles in the inflammatory response and antioxidant system regulation of these diseases. ADs are characterized by clinical heterogeneity, which impedes early diagnosis and effective personalized treatment. Redox-sensitive miRNAs and inflamma-miRs can help improve personalized medicine in these complex and heterogeneous diseases.

Astaxanthin attenuates cigarette smoking-induced oxidative stress and inflammation in a sirtuin 1-dependent manner

Oxidative stress and chronic inflammation play key roles in the pathogenesis of chronic obstructive pulmonary disease (COPD). Astaxanthin (AXT) is a keto-carotenoid with a variety of biological functions, including antioxidant and anti-inflammatory effects This study aimed to explore the protective role and underlying mechanism of AXT in the pathogenesis of COPD. In this study, we found AXT alleviated pulmonary emphysema in a CS-exposed mouse model and regulated the expression of MMP-9/TIMP-1. And, AXT attenuates CSE-induced small airway fibrosis. Meanwhile, AXT inhibited Nrf2-modulated oxidative stress and the p65 NF-κB-regulated inflammatory pathway in both the mouse model and CSE-treated HBE cells. Mechanistically, AXT could directly bind to SIRT1 (the binding energy of the complex was -8.8 kcal/mol) and regulate the deacetylation activity of SIRT1. Finally, by activating SIRT1 deacetylation, AXT deacetylated Nrf2 and contributed to its action of reducing oxidative stress by generating antioxidant enzymes, and inhibiting p65 NF-κB transcriptional activity to suppress the inflammatory response. Our results show that treatment with AXT significantly reverses the oxidative stress and inflammation induced by cigarette smoke both in vivo and in vitro in a sirtuin 1-dependent manner.