AMP-activated protein kinase inhibits NF-κB signaling and inflammation: impact on healthspan and lifespan

Anti-Apoptosis and Autophagy Effects of Melatonin Protect Rat Chondrocytes against Oxidative Stress via Regulation of AMPK/Foxo3 Pathways

OBJECTIVE

Emerging evidence has indicated that excessive reactive oxygen species (ROS) have detrimental effects on osteoarthritis (OA). This study aimed to elucidate the effects of melatonin (MT), an antioxidant indolamine secreted from the pineal gland, on chondrocyte senescence and cartilage degeneration, thereby clarifying the underlying mechanisms of ROS-induced OA pathogenesis.

DESIGN

Hydrogen peroxide (H₂O₂) was used to induce oxidative stress in rat chondrocytes. ROS levels were evaluated using cytometry and immunofluorescence. Cell viability was detected using the Cell Counting Kit-8 (CCK-8) assay. Western blotting and qPCR (Quantiative Real-Time Polymerase Chain Reaction) were used to examine apoptosis and autophagy. For in vivo experiments, male Sprague-Dawley rats were randomly divided into a sham-operated group, DMM (destabilization of the medial meniscus) surgery group, and surgery groups that received melatonin. Knee joints were collected and stained for histological analysis.

RESULTS

The data demonstrated that melatonin treatment significantly suppressed H₂O₂-induced matrix degradation and apoptosis, and maintained mitochondrial redox homeostasis. In addition, an enhancement of autophagic flux was observed through western blotting. These findings corresponded with activation of the AMPK/Foxo3 signaling pathways upon melatonin treatment. Histological staining and transmission electron microscopy (TEM) micrographs also demonstrated that melatonin alleviated cartilage ossification and chondrocyte hypertrophy in vivo.

CONCLUSIONS

Our results indicated that melatonin protected chondrocytes via mitochondrial redox homeostasis and autophagy. The effects of melatonin on senescence may apply to other age-related diseases. Thus, melatonin may have multiple potential therapeutic applications.

Mitochondrial sirtuins, metabolism, and aging

Maintaining metabolic homeostasis is essential for cellular and organismal health throughout life. Of the multiple signaling pathways that regulate metabolism, such as PI3K/AKT, mTOR, AMPK, and sirtuins, mammalian sirtuins also play unique roles in aging. By understanding how sirtuins regulate metabolic processes, we can start to understand how they slow down or accelerate biological aging. Here, we review the biology of SIRT3, SIRT4, and SIRT5, known as the mitochondrial sirtuins due to their localization in the mitochondrial matrix. First, we will focus on canonical pathways that regulate metabolism more broadly and how these are integrated with aging regulation. Then, we will summarize the current knowledge about functional differences between SIRT3, SIRT4, and SIRT5 in metabolic control and integration in signaling networks. Finally, we will discuss how mitochondrial sirtuins regulate processes associated with aging and oxidative stress, calorie restriction and disease.

β-Nicotinamide Mononucleotide (NMN) Administrated by Intraperitoneal Injection Mediates Protection Against UVB-Induced Skin Damage in Mice

Objective

Ultraviolet light is an important environmental factor that induces skin oxidation, inflammation, and other diseases. Nicotinamide mononucleotide (NMN) has the effect of anti-oxidation and improving various physiological processes. This study explores the protective effect of NMN monomers given via intraperitoneal injection on UVB-induced photodamage.

Methods

We used a murine model of UVB-induced photodamage to evaluate the effect of an NMN monomer on photoaging skin by assessing skin and liver tissue sections, serum and skin oxidative stress levels, inflammatory markers, mRNA expression, and protein expression of skin- and liver-related genes.

Results

The results showed that NMN treatment blocked UVB-induced photodamage in mice, maintaining normal structure and amount of collagen fibers, normal thickness of epidermis and dermis, reducing the production of mast cells, and maintaining complete organized skin structure. NMN intraperitoneal injection also maintained the normal morphology of the mouse liver after UVB exposure. Meanwhile, NMN intraperitoneal injection was found to increase antioxidant ability and regulate the proinflammatory response of the skin and liver to UVB irradiation by enhancing the activity of antioxidant enzymes, release of anti-inflammatory cytokines, reduction of hydrogen peroxide production (H₂O₂), and decreased inflammatory cytokines. Furthermore, RT-qPCR results indicated that NMN reduced oxidative stress of skin and liver by promoting the activation of the AMP-activated protein kinase (AMPK) signaling pathway and further increasing the expression of downstream antioxidant genes of AMPK. RT-qPCR results also revealed that NMN treatment could downregulate the mRNA expression of interleukin (IL)-6, interleukin (IL)-1β, and tumor necrosis factor (TNF)-α, and upregulate NF-kappa-B inhibitor-α (IκB-α) and interleukin (IL)-10 by inhibiting the activation of nuclear factor-κBp65 (NFκB-p65). Finally, NMN upregulated AMPK, IκB-α, SOD1, and CAT in the skin and downregulated NF-κBp65 protein expression, which is in line with the RT-qPCR results.

Conclusion

Based on the above results, NMN monomer treatment with intraperitoneal injection also block the photodamage caused by UVB irradiation in mice by regulating the oxidative stress response and inflammatory response.

Aronia melanocarpa polysaccharide ameliorates inflammation and aging in mice by modulating the AMPK/SIRT1/NF-κB signaling pathway and gut microbiota

Aronia melanocarpa is a natural medicinal plant that has a variety of biological activities, its fruit is often used for food and medicine. Aronia melanocarpa polysaccharide (AMP) is the main component of the Aronia melanocarpa fruit. This research evaluated the delay and protection of AMP obtained from Aronia melanocarpa fruit on aging mice by D-Galactose (D-Gal) induction and explored the effect of supplementing AMP on the metabolism of the intestinal flora of aging mice. The aging model was established by intraperitoneal injection of D-Gal (200 mg/kg to 1000 mg/kg) once per 3 days for 12 weeks. AMP (100 and 200 mg/kg) was given daily by oral gavage after 6 weeks of D-Gal-induced. The results showed that AMP treatment significantly improved the spatial learning and memory impairment of aging mice determined by the eight-arm maze test. H&E staining showed that AMP significantly reversed brain tissue pathological damage and structural disorders. AMP alleviated inflammation and oxidative stress injury in aging brain tissue by regulating the AMPK/SIRT1/NF-κB and Nrf2/HO-1 signaling pathways. Particularly, AMP reduced brain cell apoptosis and neurological deficits by activating the PI3K/AKT/mTOR signaling pathway and its downstream apoptotic protein family. Importantly, 16S rDNA analysis indicated the AMP treatment significantly retarded the aging process by improving the composition of intestinal flora and abundance of beneficial bacteria. In summary, this study found that AMP delayed brain aging in mice by inhibiting inflammation and regulating intestinal microbes, which providing the possibility for the amelioration and treatment of aging and related metabolic diseases.

AMPK activators for the prevention and treatment of neurodegenerative diseases

INTRODUCTION

As the global population ages at an unprecedented rate, the burden of neurodegenerative diseases is expected to grow. Given the profound impact illness like dementia exert on individuals and society writ large, researchers, physicians, and scientific organizations have called for increased investigation into their treatment and prevention. Both metformin and aspirin have been associated with improved cognitive outcomes. These agents are related in their ability to stimulate AMP kinase (AMPK). Momordica charantia, another AMPK activator, is a component of traditional medicines and a novel agent for the treatment of cancer. It is also being evaluated as a nootropic agent.

AREAS COVERED

This article is a comprehensive review which examines the role of AMPK activation in neuroprotection and the role that AMPK activators may have in the management of dementia and cognitive impairment. It evaluates the interaction of metformin, aspirin, and Momordica charantia, with AMPK, and reviews the literature characterizing these agents' impact on neurodegeneration.

EXPERT OPINION

We suggest that AMPK activators should be considered for the treatment and prevention of neurodegenerative diseases. We identify multiple areas of future investigation which may have a profound impact on patients worldwide.

Metformin protects against inflammation, oxidative stress to delay poly I:C-induced aging-like phenomena in gut of an annual fish

Metformin, a clinical agent of type 2 diabetes, is reported as a potential geroprotector. Viral infection induces phenotypes of senescence in human T cells, and polyinosinic:polycytidylic acid (poly I:C), a viral mimic, induces upregulation of SA-β-gal activity in ovary of the annual fish Nothobranchius guentheri. However, the effects and mechanisms of metformin on poly I:C-induced aging-like phenomena are poorly understood in vertebrates. In this study, the activity of SA-β-gal increased in gut of 12-month-old fish and poly I:C-injected 6-month-old fish, compared to 6-month-old control fish, indicating that poly I:C induces aging-like phenomena in gut of the fish. Metformin supplementation retarded accumulation of SA-β-gal in gut of old fish and poly I:C-treated young fish. The results of q-PCR analysis showed that metformin reduced NF-κB mediated inflammatory response including decreased level of pro-inflammatory cytokine IL-8 and increased expression of anti-inflammatory cytokine IL-10 in gut of the fish with natural aging and poly I:C-injected 6-month-old fish. Metformin also exhibited antioxidant effects, as it reduced ROS production which is associated with the upregulation of FoxO3a and PGC-1α in gut of 6-month-old fish with poly I:C-injection. Expression of AMPK and SIRT1 was reduced in gut of 6-month-old fish with poly I:C-treatment, and feeding metformin reversed these declines. Taken together, the present study suggested that poly I:C-injection led to aging-like phenomena in gut and metformin activated AMPK and SIRT1 to reduce NF-κB mediated inflammation and resist oxidative stress via enhanced expression of FoxO3a and PGC-1α, and finally delayed gut aging in vertebrates.

Hesperetin Exhibits Anti-Inflammatory Effects on Chondrocytes via the AMPK Pathway to Attenuate Anterior Cruciate Ligament Transection-Induced Osteoarthritis

This study aimed to determine whether hesperetin (HPT) has chondroprotective effects against the TNF-α-induced inflammatory response of chondrocytes and related mechanisms and clarify the impact of HPT on osteoarthritis (OA) induced by anterior cruciate ligament transection (ACLT). Under tumor necrosis factor-α (TNF-α) stimulation, rat chondrocytes were treated with or without HPT. The CCK-8 assay was used to detect viability and cytotoxicity. RT-qPCR and Western blot were used to examine the expression of aggrecan, collagen type II, and inflammatory and proliferative genes/proteins in chondrocytes. Flow cytometry was used to check the cell cycle to determine whether HPT protects chondrocytes against the inhibitory effect of TNF-α on chondrocyte proliferation. In addition, RNA sequencing was used to discover possible molecular targets and pathways and then validate these pathways with specific protein phosphorylation levels. Finally, immunofluorescence staining was used to examine the phosphorylation of the AMP-activated protein kinase (AMPK) pathway. The results showed that HPT restored the upregulation of interleukin 1β (IL-1β), PTGS2, and MMP-13 induced by TNF-α. In addition, HPT reversed the degradation of the extracellular matrix of chondrocytes induced by TNF-α. HPT also reversed the inhibitory effect of TNF-α on chondrocyte proliferation. RNA sequencing revealed 549 differentially expressed genes (DEGs), of which 105 were upregulated and 444 were downregulated, suggesting the potential importance of the AMPK pathway. Progressive analysis showed that HPT mediated the repair of TNF-α-induced chondrocyte damage through the AMPK signaling pathway. Thus, local treatment of HPT can improve OA induced by ACLT. These findings indicated that HPT has significant protective and anti-inflammatory effects on chondrocytes through the AMPK signaling pathway, effectively preventing cartilage degradation. Given the various beneficial effects of HPT, it can be used as a potential natural drug to treat OA.

Adverse Effects of Metformin From Diabetes to COVID-19, Cancer, Neurodegenerative Diseases, and Aging: Is VDAC1 a Common Target?

Metformin has been used for treating diabetes mellitus since the late 1950s. In addition to its antihyperglycemic activity, it was shown to be a potential drug candidate for treating a range of other diseases that include various cancers, cardiovascular diseases, diabetic kidney disease, neurodegenerative diseases, renal diseases, obesity, inflammation, COVID-19 in diabetic patients, and aging. In this review, we focus on the important aspects of mitochondrial dysfunction in energy metabolism and cell death with their gatekeeper VDAC1 (voltage-dependent anion channel 1) as a possible metformin target, and summarize metformin's effects in several diseases and gut microbiota. We question how the same drug can act on diseases with opposite characteristics, such as increasing apoptotic cell death in cancer, while inhibiting it in neurodegenerative diseases. Interestingly, metformin's adverse effects in many diseases all show VDAC1 involvement, suggesting that it is a common factor in metformin-affecting diseases. The findings that metformin has an opposite effect on various diseases are consistent with the fact that VDAC1 controls cell life and death, supporting the idea that it is a target for metformin.

Camellia japonica diminishes acetaminophen-induced acute liver failure by attenuating oxidative stress in mice

This experiment was to explore the possible defensive properties and potential molecular mechanisms of Camellia japonica (CJ) against APAP-stimulated acute liver failure (ALF) in mice. In this study, we investigated the effects of CJ on APAP-induced hepatotoxicity. Mice were orally treated with CJ before or after challenge with APAP. Both pretreatment and post-treatment with CJ attenuated APAP-induced hepatotoxicity, as confirmed by significantly reduced serum toxicity biomarkers and improved hepatic pathological damage. Pretreatment with CJ drastically decreased the rise of hepatic inflammatory cytokines levels and weakened neutrophil infiltration. Furthermore, pretreatment with CJ dramatically decreased the levels of hepatic oxidative stress markers such as hepatic malondialdehyde (MDA) and 4-Hydroxynonenal (4-HNE) expression and rescued the reduced hepatic level of GSH caused by APAP overdose. Additionally, CJ pretreatment markedly attenuated cyclooxygenase-2 (COX-2) activation, transcription factor nuclear factor-kappa B (NF-κB) phosphorylation, c-Jun-N-terminal kinase (JNK) phosphorylation, and activated AMP-activated protein kinase (AMPK) signaling pathway in the liver. The present study thus reveals that CJ attenuated APAP-induced ALF by inhibiting COX-2 activation, NF-κB, and JNK phosphorylation and activating the AMPK signaling pathway.

Metformin Therapy Attenuates Pro-inflammatory Microglia by Inhibiting NF-κB in Cuprizone Demyelinating Mouse Model of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic disorder characterized by reactive gliosis, inflammation, and demyelination. Microglia plays a crucial role in the pathogenesis of MS and has the dynamic plasticity to polarize between pro-inflammatory (M1) and anti-inflammatory (M2) phenotypes. Metformin, a glucose-lowering drug, attenuates inflammatory responses by activating adenosine monophosphate protein kinase (AMPK) which suppresses nuclear factor kappa B (NF-κB). In this study, we indirectly investigated whether metformin therapy would regulate microglia activity in the cuprizone (CPZ)-induced demyelination mouse model of MS via measuring the markers associated with pro- and anti-inflammatory microglia. Evaluation of myelin by luxol fast blue staining revealed that metformin treatment (CPZ + Met) diminished demyelination, in comparison to CPZ mice. In addition, metformin therapy significantly alleviated reactive microgliosis and astrogliosis in the corpus callosum, as measured by Iba-1 and GFAP staining. Moreover, metformin treatment significantly downregulated the expression of pro-inflammatory associated genes (iNOS, H2-Aa, and TNF-α) in the corpus callosum, whereas expression of anti-inflammatory markers (Arg1, Mrc1, and IL10) was not promoted, compared to CPZ mice. Furthermore, protein levels of iNOS (pro-inflammatory marker) were significantly decreased in the metformin group, while those of Trem2 (anti-inflammatory marker) were increased. In addition, metformin significantly increased AMPK activation in CPZ mice. Finally, metformin administration significantly reduced the activation level of NF-κB in CPZ mice. In summary, our data revealed that metformin attenuated pro-inflammatory microglia markers through suppressing NF-κB activity. The positive effects of metformin on microglia and remyelination suggest that it could be used as a promising candidate to lessen the incidence of inflammatory neurodegenerative diseases such as MS.

Metabolomic Profiles of Men and Women Ischemic Stroke Patients

Background: Stroke is known to affect both men and women; however, incidence and outcomes differ between them. Therefore, the discovery of novel, sex-specific, blood-based biomarkers for acute ischemic stroke (AIS) patients has the potential to enhance the understanding of the etiology of this deadly disease in the content of sex. The objective of this study was to identify serum metabolites associated with male and female AIS patients. Methods: Metabolites were measured with the use of untargeted, reverse-phase ultra-performance liquid chromatography-tandem mass spectrometry quantification from blood specimens collected from AIS patients. Samples were collected from 36 patients comprising each of 18 men and women with matched controls. Metabolic pathway analysis and principal component analysis (PCA) was used to differentiate metabolite profiles for male and female AIS patients from the control, while logistic regression was used to determine differences in metabolites between male and female AIS patients. Results: In female AIS patients, 14 distinct altered metabolic pathways and 49 corresponding metabolites were identified, while 39 metabolites and 5 metabolic pathways were identified in male patients. Metabolites that are predictive of ischemic stroke in female patients were 1-(1-enyl-palmitoyl)-2-arachidonoyl-GPC (P-16:0/20:4) (AUC = 0.914, 0.765–1.000), 1-(1-enyl-palmitoyl)-2-palmitoyl-GPC (P-16:0/16:0) (AUC = 0.840, 0.656–1.000), and 5,6-dihydrouracil (P-16:0/20:2) (AUC = 0.815, 0.601–1.000). Significant metabolites that were predictive of stroke in male patients were 5alpha-androstan-3alpha,17beta-diol disulfate (AUC = 0.951, 0.857–1.000), alpha-hydroxyisocaproate (AUC = 0.938, 0.832–1.000), threonate (AUC = 0.877, 0.716–1.000), and bilirubin (AUC = 0.817, 0.746–1.000). Conclusions: In the current study, the untargeted serum metabolomics platform identified multiple pathways and metabolites associated with male and female AIS patients. Further research is necessary to characterize how these metabolites are associated with the pathophysiology in male and female AIS patients.

Deficiency of miR-29b2/c leads to accelerated aging and neuroprotection in MPTP-induced Parkinson's disease mice

Studies reveal a linkage of miR-29s in aging and Parkinson's disease (PD). Here we show that the serum levels of miR-29s in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice exhibited dynamic changes. The role of miR-29b2/c in aging and PD was studied utilizing miR-29b2/c gene knockout mice (miR-29b2/c KO). miR-29b2/c KO mice were characterized by a markedly lighter weight, kyphosis, muscle weakness and abnormal gait, when compared with wild-type (WT) mice. The WT also developed apparent dermis thickening and adipose tissue reduction. However, deficiency of miR-29b2/c alleviated MPTP-induced damages of the dopaminergic system and glial activation in the nigrostriatal pathway and consequently improved the motor function of MPTP-treated KO mice. Knockout of miR-29b2/c inhibited the expression of inflammatory factors in 1-methyl-4-phenylpyridinium (MPP⁺)-treated primary cultures of mixed glia, primary astrocytes, or LPS-treated primary microglia. Moreover, miR-29b2/c deficiency enhanced the activity of AMPK but repressed the NF-κB p65 signaling in glial cells. Our results show that miR-29b2/c KO mice display the progeria-like phenotype. Less activated glial cells and repressed neuroinflammation might bring forth dopaminergic neuroprotection in miR-29b2/c KO mice. Conclusively, miR-29b2/c is involved in the regulation of aging and plays a detrimental role in Parkinson's disease.

The protective effects of 17-β estradiol and SIRT1 against cardiac hypertrophy: a review

One of the major causes of morbidity and mortality worldwide is cardiac hypertrophy (CH), which leads to heart failure. Sex differences in CH can be caused by sex hormones or their receptors. The incidence of CH increases in postmenopausal women due to the decrease in female sex hormone 17-β estradiol (E2) during menopause. E2 and its receptors inhibit CH in humans and animal models. Silent information regulator 1 (SIRT1) is a NAD⁺-dependent HDAC (histone deacetylase) and plays a major role in biological processes, such as inflammation, apoptosis, and oxidative stress responses. Probably SIRT1 because of these effects, is one of the main suppressors of CH and has a cardioprotective effect. On the other hand, estrogen and its agonists are highly efficient in modulating SIRT1 expression. In the present study, we review the protective effects of E2 and SIRT1 against CH.

Effects of Sodium Selenite Injection on Serum Metabolic Profiles in Women Diagnosed with Breast Cancer-Related Lymphedema-Secondary Analysis of a Randomized Placebo-Controlled Trial Using Global Metabolomics

In our previous study, intravenous (IV) injection of selenium alleviated breast cancer-related lymphedema (BCRL). This secondary analysis aimed to explore the metabolic effects of selenium on patients with BCRL. Serum samples of the selenium-treated (SE, n = 15) or the placebo-controlled (CTRL, n = 14) groups were analyzed by ultra-high-performance liquid chromatography with Q-Exactive Orbitrap tandem mass spectrometry (UHPLC-Q-Exactive Orbitrap/MS). The SE group showed a lower ratio of extracellular water to segmental water (ECW/SW) in the affected arm to ECW/SW in the unaffected arm (arm ECW/SW ratio) than the CTRL group. Metabolomics analysis showed a valid classification at 2-weeks and 107 differential metabolites were identified. Among them, the levels of corticosterone, LTB4-DMA, and PGE₃—which are known anti-inflammatory compounds—were elevated in the SE group. Pathway analysis demonstrated that lipid metabolism (glycerophospholipid metabolism, steroid hormone biosynthesis, or arachidonic acid metabolism), nucleotide metabolism (pyrimidine or purine metabolism), and vitamin metabolism (pantothenate and CoA biosynthesis, vitamin B₆ metabolism, ascorbate and aldarate metabolism) were altered in the SE group compared to the CTRL group. In addition, xanthurenic acid levels were negatively associated with whole blood selenium level (WBSe) and positively associated with the arm ECW/SW. In conclusion, selenium IV injection improved the arm ECW/SW ratio and altered the serum metabolic profiles in patients with BCRL, and improved the anti-inflammatory process in lipid, nucleotide and vitamin pathways, which might alleviate the symptoms of BCRL.

Novel Characterization of Myeloid-Derived Suppressor Cells in Tumor Microenvironment

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of cells generated in various pathologic conditions, which have been known to be key components of the tumor microenvironment (TME) involving in tumor immune tolerance. So MDSCs have been extensively researched recently. As its name suggests, immunosuppression is the widely accepted function of MDSCs. Aside from suppressing antitumor immune responses, MDSCs in the TME also stimulate tumor angiogenesis and metastasis, thereby promoting tumor growth and development. Therefore, altering the recruitment, expansion, activation, and immunosuppression of MDSCs could partially restore antitumor immunity. So, this view focused on the favorable TME conditions that promote the immunosuppressive effects of MDSCs and contribute to targeted therapies with increased precision for MDSCs.

L-carnitine and Co Q10 ameliorate potassium dichromate -induced acute brain injury in rats targeting AMPK/AKT/NF-κβ

Adenosine monophosphate-activated protein kinase (AMPK) has a crucial role in neuroprotection. It phosphorylates serine/threonine kinase (Akt) Substrate inhibiting the inflammatory responses induced by the nuclear factor-κB (NF-κB). Exposure to chromium VI dust among workers has been reported and induced brain injury, as the absorption of chromium through the nasal membrane has been found to deliver it directly to the brain. The study aimed to investigate the influence of administration of L-carnitine or/and Co Q10 as theraputic agents against potassium dichromate (PD)-induced brain injury via AMPK/AKT/NF-κβ signaling pathway. Brain injury was induced by PD intranasally as a single dose of 2 mg/kg, 24 h latter rats received L-carnitine (100 mg/kg; orally), Co Q10 (50 mg/kg; orally) and L-carnitine (50 mg/kg; orally) + Co Q10 (25 mg/kg; orally) respectively for 3 days. Locomotor activity was assessed before and at the end of the experiment, then, biochemical and histopathological investigations were assessed in brain homogenate. The exposure of rats to PD promoted oxidative stress and inflammation via an increase in MDA and a decrease in GSH serum contents with an increase in brain contents of TNF-α, IL-6, and NF-kβ and reduced AMPK and AKT brain contents as compared to the control group. Treatment with L-carnitine + Co Q10 ameliorated cognitive impairment and oxidative stress, decreased the brain contents of inflammatory mediators; TNF-α, IL-6, and NF-κβ elevated AMPK and AKT, as compared to each drug. Also, L-carnitine + Co Q10 administration restored morphological changes as degenerated neurons and necrosis. L-carnitine + Co Q10 play important role in AMPK/AKT/NF-κβ pathway that responsible for their antioxidant and anti-inflammatory effects against PD-induced brain injury in rats.

Metformin Attenuates Silica-Induced Pulmonary Fibrosis by Activating Autophagy via the AMPK-mTOR Signaling Pathway

Long-term exposure to crystalline silica particles leads to silicosis characterized by persistent inflammation and progressive fibrosis in the lung. So far, there is no specific treatment to cure the disease other than supportive care. In this study, we examined the effects of metformin, a prescribed drug for type || diabetes on silicosis and explored the possible mechanisms in an established rat silicosis model in vivo, and an in vitro co-cultured model containing human macrophages cells (THP-1) and human bronchial epithelial cells (HBEC). Our results showed that metformin significantly alleviated the inflammation and fibrosis of lung tissues of rats exposed to silica particles. Metformin significantly reduced silica particle-induced inflammatory cytokines including transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in rat lung tissue and HBEC culture supernatant. The protein levels of Vimentin and α-smooth muscle actin (α-SMA) were significantly decreased by metfomin while expression level of E-cadherin (E-Cad) increased. Besides, metformin increased the expression levels of phosphorylated adenosine 5′-monophosphate (AMP)-activated protein kinase (p-AMPK), microtubule-associated protein (MAP) light chain 3B (LC3B) and Beclin1 proteins, and reduced levels of phosphorylated mammalian target of rapamycin (p-mTOR) and p62 proteins in vivo and in vitro. These results suggest that metformin could inhibit silica-induced pulmonary fibrosis by activating autophagy through the AMPK-mTOR pathway.

The Evolution of the Hallmarks of Aging

The evolutionary theory of aging has set the foundations for a comprehensive understanding of aging. The biology of aging has listed and described the "hallmarks of aging," i.e., cellular and molecular mechanisms involved in human aging. The present paper is the first to infer the order of appearance of the hallmarks of bilaterian and thereby human aging throughout evolution from their presence in progressively narrower clades. Its first result is that all organisms, even non-senescent, have to deal with at least one mechanism of aging - the progressive accumulation of misfolded or unstable proteins. Due to their cumulation, these mechanisms are called "layers of aging." A difference should be made between the first four layers of unicellular aging, present in some unicellular organisms and in all multicellular opisthokonts, that stem and strike "from the inside" of individual cells and span from increasingly abnormal protein folding to deregulated nutrient sensing, and the last four layers of metacellular aging, progressively appearing in metazoans, that strike the cells of a multicellular organism "from the outside," i.e., because of other cells, and span from transcriptional alterations to the disruption of intercellular communication. The evolution of metazoans and eumetazoans probably solved the problem of aging along with the problem of unicellular aging. However, metacellular aging originates in the mechanisms by which the effects of unicellular aging are kept under control - e.g., the exhaustion of stem cells that contribute to replace damaged somatic cells. In bilaterians, additional functions have taken a toll on generally useless potentially limited lifespan to increase the fitness of organisms at the price of a progressively less efficient containment of the damage of unicellular aging. In the end, this picture suggests that geroscience should be more efficient in targeting conditions of metacellular aging rather than unicellular aging itself.

High-Carbohydrate Diet Alleviates the Oxidative Stress, Inflammation and Apoptosis of Megalobrama amblycephala Following Dietary Exposure to Silver Nanoparticles

A 12-week feeding trial was performed to evaluate the effects of high-carbohydrate diet on oxidative stress, inflammation and apoptosis induced by silver nanoparticles (Ag-NPs) in M. amblycephala. Fish (20.12 ± 0.85 g) were randomly fed four diets (one control diet (C, 30% carbohydrate), one control diet supplemented with 100 mg kg⁻¹ Ag-NPs (CS), one high-carbohydrate diet (HC, 45% carbohydrate) and one HC diet supplemented with 100 mg kg⁻¹ Ag-NPs (HCS)). The results indicated that weight gain rate (WGR), specific growth rate (SGR), antioxidant enzyme (SOD and CAT) activities and expression of Trx, Cu/Zn-SOD, Mn-SOD, CAT and GPx1 of fish fed CS diet were all remarkably lower than those of other groups, whereas the opposite was true for plasma IL 1β and IL 6 levels, liver ROS contents, hepatocytes apoptotic rate, AMP/ATP ratio, AMPKα, P 53 and caspase 3 protein contents and mRNA levels of AMPKα 1, AMPKα 2, TXNIP, NF-κB, TNFα, IL 1β, IL 6, P 53, Bax and caspase 3. However, high-carbohydrate diet remarkably increased WGR, SGR, liver SOD and CAT activities, AMPKα protein content and mRNA levels of antioxidant genes (Cu/Zn-SOD, Mn-SOD, CAT and GPx1), anti-inflammatory cytokines (IL 10) and anti-apoptotic genes (Bcl 2) of fish facing Ag-NPs compared with the CS group, while the opposite was true for liver ROS contents, hepatocytes apoptotic rate, P 53 and caspase 3 protein contents, as well as mRNA levels of TXNIP, NF-κB, TNFα, IL 1β, IL 6, P 53, Bax and caspase 3. Overall, high-carbohydrate diet could attenuate Ag-NPs-induced hepatic oxidative stress, inflammation and apoptosis of M. amblycephala through AMPK activation.

Dietary Control of Inflammation and Resolution

The healing of any injury requires a dynamic balance of initiation and resolution of inflammation. This hypothesis-generating review presents an overview of the various nutrients that can act as signaling agents to modify the metabolic responses essential for the optimal healing of injury-induced inflammation. In this hypothesis-generating review, we describe a defined nutritional program consisting of an integrated interaction of a calorie-restricted anti-inflammatory diet coupled with adequate levels of omega-3 fatty acids and sufficient levels of dietary polyphenols that can be used in clinical trials to treat conditions associated with insulin resistance. Each dietary intervention works in an orchestrated systems-based approach to reduce, resolve, and repair the tissue damage caused by any inflammation-inducing injury. The orchestration of these specific nutrients and their signaling metabolites to facilitate healing is termed the Resolution Response. The final stage of the Resolution Response is the activation of intracellular 5' adenosine monophosphate-activated protein kinase (AMPK), which is necessary to repair tissue damaged by the initial injury-induced inflammation. The dietary optimization of the Resolution Response can be personalized to the individual by using standard blood markers. Once each of those markers is in their appropriate ranges, activation of intracellular AMPK will be facilitated. Finally, we outline how the resulting activation of AMPK will affect a diverse number of other intercellular signaling systems leading to an extended healthspan.

Cigarette smoking and nicotine exposure contributes for aberrant insulin signaling and cardiometabolic disorders

Cigarette smoking- and nicotine-mediated dysregulation in insulin-signaling pathways are becoming leading health issues associated with morbidity and mortality worldwide. Many cardiometabolic disorders particularly insulin resistance, polycystic ovary syndrome (PCOS), central obesity and cardiovascular diseases are initiated from exposure of exogenous substances which augment by disturbances in insulin signaling cascade. Among these exogenous substances, nicotine and cigarette smoking are potential triggers for impairment of insulin-signaling pathways. Further, this aberrant insulin signaling is associated with many metabolic complications, which consequently give rise to initiation as well as progression of these metabolic syndromes. Hence, understanding the underlying molecular mechanisms responsible for cigarette smoking- and nicotine-induced altered insulin signaling pathways and subsequent participation in several health hazards are quite essential for prophylaxis and combating these complications. In this article, we have focused on the role of nicotine and cigarette smoking mediated pathological signaling; for instance, nicotine-mediated inhibition of nuclear factor erythroid 2-related factor 2 and oxidative damage, elevated cortisol that may promote central obesity, association PCOS and oxidative stress via diminished nitric oxide which may lead to endothelial dysfunction and vascular inflammation. Pathological underlying molecular mechanisms involved in mediating these metabolic syndromes via alteration of insulin signaling cascade and possible molecular mechanism responsible for these consequences on nicotine exposure have also been discussed.

Neuroprotective Potential of Limonene and Limonene Containing Natural Products

Limonene is a monoterpene confined to the family of Rutaceae, showing several biological properties such as antioxidant, anti-inflammatory, anticancer, antinociceptive and gastroprotective characteristics. Recently, there is notable interest in investigating the pharmacological effects of limonene in various chronic diseases due to its mitigating effect on oxidative stress and inflammation and regulating apoptotic cell death. There are several available studies demonstrating the neuroprotective role of limonene in neurodegenerative diseases, including Alzheimer's disease, multiple sclerosis, epilepsy, anxiety, and stroke. The high abundance of limonene in nature, its safety profile, and various mechanisms of action make this monoterpene a favorable molecule to be developed as a nutraceutical for preventive purposes and as an alternative agent or adjuvant to modern therapeutic drugs in curbing the onset and progression of neurodegenerative diseases. This manuscript presents a comprehensive review of the available scientific literature discussing the pharmacological activities of limonene or plant products containing limonene which attribute to the protective and therapeutic ability in neurodegenerative disorders. This review has been compiled based on the existing published articles confined to limonene or limonene-containing natural products investigated for their neurotherapeutic or neuroprotective potential. All the articles available in English or the abstract in English were extracted from different databases that offer an access to diverse journals. These databases are PubMed, Scopus, Google Scholar, and Science Direct. Collectively, this review emphasizes the neuroprotective potential of limonene against neurodegenerative and other neuroinflammatory diseases. The available data are indicative of the nutritional use of products containing limonene and the pharmacological actions and mechanisms of limonene and may direct future preclinical and clinical studies for the development of limonene as an alternative or complementary phytomedicine. The pharmacophore can also provide a blueprint for further drug discovery using numerous drug discovery tools.

A proprietary herbal drug Young Yum Pill ameliorates chronic fatigue syndrome in mice

BACKGROUND

Chronic fatigue syndrome (CFS) is a complex disease with few effective and safe therapies. Young Yum Pill (YYP), a proprietary herbal drug, has been used to relieve CFS-like symptoms. The pharmacological basis of this application of YYP is unknown.

PURPOSE

This study aimed to investigate the pharmacological effects and mechanisms of action of YYP in a mouse model of CFS.

STUDY DESIGN AND METHODS

A food restriction and exhaustive swimming-induced mouse CFS model was used to evaluate the effects of YYP. Lymphocyte proliferation was assessed by MTT assays. T-lymphocyte subsets were analyzed by flow cytometry. Serum biochemical parameters were determined using commercial kits. Protein levels were measured by immunoblotting.

RESULTS

Intragastric administration of YYP (2.85, 5.70, 11.40 g/kg) daily for 21 consecutive days significantly prolonged swimming time and diminished body weight loss of CFS mice. Mechanistic investigations revealed that YYP increased thymus and spleen indices of CFS mice, enhanced proliferation of lipopolysaccharide- or concanavalin A-stimulated spleen lymphocytes, and increased CD3+CD4+ and CD3+CD8+ T-cells in the spleen. YYP increased glycogen content in gastrocnemius muscle and liver, and lowered levels of triglyceride, lactic acid and urea nitrogen in sera of CFS mice. YYP suppressed the elevation of serum level of malondialdehyde, the increase of activities of lactic dehydrogenase and creatine phosphokinase, and the decrease of activity of the serum antioxidant enzyme superoxide dismutase in CFS mice. Moreover, YYP upregulated protein level of activated AMPK in gastrocnemius muscle and liver of CFS mice.

CONCLUSIONS

YYP ameliorates CFS by reversing metabolic changes, reducing oxidative damage, and improving some immune function parameters in mice. This study provides pharmacological justifications for the use of YYP in treating fatigue, including CFS.

Function of Uric Acid Transporters and Their Inhibitors in Hyperuricaemia

Disorders of uric acid metabolism may be associated with pathological processes in many diseases, including diabetes mellitus, cardiovascular disease, and kidney disease. These diseases can further promote uric acid accumulation in the body, leading to a vicious cycle. Preliminary studies have proven many mechanisms such as oxidative stress, lipid metabolism disorders, and rennin angiotensin axis involving in the progression of hyperuricaemia-related diseases. However, there is still lack of effective clinical treatment for hyperuricaemia. According to previous research results, NPT1, NPT4, OAT1, OAT2, OAT3, OAT4, URAT1, GLUT9, ABCG2, PDZK1, these urate transports are closely related to serum uric acid level. Targeting at urate transporters and urate-lowering drugs can enhance our understanding of hyperuricaemia and hyperuricaemia-related diseases. This review may put forward essential references or cross references to be contributed to further elucidate traditional and novel urate-lowering drugs benefits as well as provides theoretical support for the scientific research on hyperuricemia and related diseases.

α-Hydroxyisocaproic Acid Decreases Protein Synthesis but Attenuates TNFα/IFNγ Co-Exposure-Induced Protein Degradation and Myotube Atrophy via Suppression of iNOS and IL-6 in Murine C2C12 Myotube

There is ongoing debate as to whether or not α-hydroxyisocaproic acid (HICA) positively regulates skeletal muscle protein synthesis resulting in the gain or maintenance of skeletal muscle. We investigated the effects of HICA on mouse C2C12 myotubes under normal conditions and during cachexia induced by co-exposure to TNFα and IFNγ. The phosphorylation of AMPK or ERK1/2 was significantly altered 30 min after HICA treatment under normal conditions. The basal protein synthesis rates measured by a deuterium-labeling method were significantly lowered by the HICA treatment under normal and cachexic conditions. Conversely, myotube atrophy induced by TNFα/IFNγ co-exposure was significantly improved by the HICA pretreatment, and this improvement was accompanied by the inhibition of iNOS expression and IL-6 production. Moreover, HICA also suppressed the TNFα/IFNγ co-exposure-induced secretion of 3-methylhistidine. These results demonstrated that HICA decreases basal protein synthesis under normal or cachexic conditions; however, HICA might attenuate skeletal muscle atrophy via maintaining a low level of protein degradation under cachexic conditions.

Melatonin alleviates Ochratoxin A-induced liver inflammation involved intestinal microbiota homeostasis and microbiota-independent manner

Melatonin (MEL) shows an anti-inflammatory effect and regulates intestinal microbiota communities in animals and humans; Ochratoxin A (OTA) induces liver inflammation through intestinal microbiota. However, it remains to know whether MEL alleviates the liver inflammation induced by OTA. In this study, MEL reversed various adverse effects induced by OTA. MEL recovered the swarming and motility of intestinal microbiota, decreased the accumulation of lipopolysaccharide (LPS), enhanced the tight junction proteins of jejunum and cecum segments; ultimately alleviated OTA-induced liver inflammation in ducks. However, it is worth noting that MEL still had positive effects on the OTA-exposed ducks after antibiotic treatment. These results suggest that both the maintenance of intestinal microbiota homeostasis and intestinal microbiota-independent manner involved the MEL anti-inflammatory function in OTA-induced liver inflammation. MEL represent a promising protective approach for OTA, even other mycotoxins.

Metformin Inhibits Lipoteichoic Acid-Induced Oxidative Stress and Inflammation Through AMPK/NRF2/NF-κB Signaling Pathway in Bovine Mammary Epithelial Cells

The objective of this research was to explore the effect of metformin on the lipoteichoic acid (LTA)–induced mastitis model using isolated primary bovine mammary epithelial cells (PBMECs). The PBMECs were exposed to either 3 mM metformin for 12 h as a metformin group (MET) or 100 μg/mL LTA for 6 h as LTA group (LTA). Cells pretreated with 3 mM metformin for 12 h followed by washing and 100 μg/mL LTA exposure for 6 h served as the MET + LTA group. Phosphate-buffered saline was added to cells as the control group. PBMECs pretreated with different metformin doses were analyzed by a flow cytometry (annexin V–fluorescein isothiocyanate assay) to detect the cell apoptotic rate. We performed quantitative reverse transcriptase–polymerase chain reaction and Western blot analysis to evaluate the inflammatory and oxidative responses to metformin and LTA by measuring cellular cytotoxicity, mRNA expression, and protein expression. Immunofluorescence was used to evaluate nuclear localization. The results showed that the gene expression of COX2, IL-1β, and IL-6 significantly increased in the cells challenged with LTA doses compared to control cells. In inflammatory PBMECs, metformin attenuated LTA-induced expression of inflammatory genes nuclear factor κB (NF-κB) p65, tumor necrosis factor α, cyclooxygenase 2, and interleukin 1β, as well as the nuclear localization and phosphorylation of NF-κBp65 protein, but increased the transcription of nuclear factor erythroid 2–related factor 2 (Nrf2) and Nrf2-targeted antioxidative genes heme oxygenase-1 (HO-1) and Gpx1, as well as the nuclear localization of HO-1 protein. Importantly, metformin-induced activation of Nrf2 is AMP-activated protein kinase (AMPK)–dependent; as metformin-pretreated PBMECs activated AMPK signaling via the upregulation of phosphorylated AMPK levels, cell pretreatment with metformin also reversed the translocation of Nrf2 that was LTA inhibited. This convergence between AMPK and Nrf2 pathways is essential for the anti-inflammatory effect of metformin in LTA-stimulated PBMECs. Altogether, our results indicate that metformin exerts anti-inflammation and oxidative stress through regulation of AMPK/Nrf2/NF-κB signaling pathway, which highlights the role of AMPK as a potential therapeutic strategy for treatment of bovine mastitis.

Beneficial Effects of Exogenous Ketogenic Supplements on Aging Processes and Age-Related Neurodegenerative Diseases

Life expectancy of humans has increased continuously up to the present days, but their health status (healthspan) was not enhanced by similar extent. To decrease enormous medical, economical and psychological burden that arise from this discrepancy, improvement of healthspan is needed that leads to delaying both aging processes and development of age-related diseases, thereby extending lifespan. Thus, development of new therapeutic tools to alleviate aging processes and related diseases and to increase life expectancy is a topic of increasing interest. It is widely accepted that ketosis (increased blood ketone body levels, e.g., β-hydroxybutyrate) can generate neuroprotective effects. Ketosis-evoked neuroprotective effects may lead to improvement in health status and delay both aging and the development of related diseases through improving mitochondrial function, antioxidant and anti-inflammatory effects, histone and non-histone acetylation, β-hydroxybutyrylation of histones, modulation of neurotransmitter systems and RNA functions. Administration of exogenous ketogenic supplements was proven to be an effective method to induce and maintain a healthy state of nutritional ketosis. Consequently, exogenous ketogenic supplements, such as ketone salts and ketone esters, may mitigate aging processes, delay the onset of age-associated diseases and extend lifespan through ketosis. The aim of this review is to summarize the main hallmarks of aging processes and certain signaling pathways in association with (putative) beneficial influences of exogenous ketogenic supplements-evoked ketosis on lifespan, aging processes, the most common age-related neurodegenerative diseases (Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis), as well as impaired learning and memory functions.

Targeting Future Pandemics, a Case for De Novo Purine Synthesis and Basic Research

We are currently experiencing a deadly novel viral pandemic with no efficacious, readily available anti-viral therapies to SARS-CoV-2. Viruses will hijack host cellular machinery, including metabolic processes. Here, I provide theory and evidence for targeting the host de novo purine synthetic pathway for broad spectrum anti-viral drug development as well as the pursuit of basic science to mitigate the risks of future novel viral outbreaks.

Early glycolytic reprogramming controls microglial inflammatory activation

Background

Microglial activation-mediated neuroinflammation plays an important role in the progression of neurodegenerative diseases. Inflammatory activation of microglial cells is often accompanied by a metabolic switch from oxidative phosphorylation to aerobic glycolysis. However, the roles and molecular mechanisms of glycolysis in microglial activation and neuroinflammation are not yet fully understood.

Methods

The anti-inflammatory effects and its underlying mechanisms of glycolytic inhibition in vitro were examined in lipopolysaccharide (LPS) activated BV-2 microglial cells or primary microglial cells by enzyme-linked immunosorbent assay (ELISA), quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot, immunoprecipitation, flow cytometry, and nuclear factor kappa B (NF-κB) luciferase reporter assays. The anti-inflammatory and neuroprotective effects of glycolytic inhibitor, 2-deoxoy-d-glucose (2-DG) in vivo were measured in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-or LPS-induced Parkinson’s disease (PD) models by immunofluorescence staining, behavior tests, and Western blot analysis.

Results

We found that LPS rapidly increased glycolysis in microglial cells, and glycolysis inhibitors (2-DG and 3-bromopyruvic acid (3-BPA)), siRNA glucose transporter type 1 (Glut-1), and siRNA hexokinase (HK) 2 abolished LPS-induced microglial cell activation. Mechanistic studies demonstrated that glycolysis inhibitors significantly inhibited LPS-induced phosphorylation of mechanistic target of rapamycin (mTOR), an inhibitor of nuclear factor-kappa B kinase subunit beta (IKKβ), and NF-kappa-B inhibitor alpha (IκB-α), degradation of IκBα, nuclear translocation of p65 subunit of NF-κB, and NF-κB transcriptional activity. In addition, 2-DG significantly inhibited LPS-induced acetylation of p65/RelA on lysine 310, which is mediated by NAD-dependent protein deacetylase sirtuin-1 (SIRT1) and is critical for NF-κB activation. A coculture study revealed that 2-DG reduced the cytotoxicity of activated microglia toward MES23.5 dopaminergic neuron cells with no direct protective effect. In an LPS-induced PD model, 2-DG significantly ameliorated neuroinflammation and subsequent tyrosine hydroxylase (TH)-positive cell loss. Furthermore, 2-DG also reduced dopaminergic cell death and microglial activation in the MPTP-induced PD model.

Conclusions

Collectively, our results suggest that glycolysis is actively involved in microglial activation. Inhibition of glycolysis can ameliorate microglial activation-related neuroinflammatory diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02187-y.

Palmitoleic acid ameliorates palmitic acid-induced proinflammation in J774A.1 macrophages via TLR4-dependent and TNF-α-independent signallings

Adipose tissue resident macrophages play an important role in the regulation of the inflammatory response. Monounsaturated fatty acids assist in the prevention of cardiovascular diseases via an anti-inflammatory effect. However, the mechanisms by which monounsaturated fatty acids, such as palmitoleic acid, regulate the inflammatory response has not been well investigated. In this study, we found that a high concentration of palmitic acid induced J774A.1 murine macrophages toward a pro-inflammatory state, possibly through the activation of the TLR2 or TLR4 genes, and their downstream signaling pathways. In contrast, palmitoleic acid induced a protective effect against inflammation in macrophage of non-obese rodents by inducing an alternative activation pathway via reducing TLR2 or TLR4 signaling. This study indicates that the balance of palmitic acid (saturated fatty acid) and palmitoleic acid (monounsaturated fatty acid) effects macrophage activation. The potential therapeutic impact of palmitoleic acid to ameliorate non-obese-mediated inflammation warrants further investigation.

Beneficial Effects of Metformin on the Central Nervous System, with a Focus on Epilepsy and Lafora Disease

Metformin is a drug in the family of biguanide compounds that is widely used in the treatment of type 2 diabetes (T2D). Interestingly, the therapeutic potential of metformin expands its prescribed use as an anti-diabetic drug. In this sense, it has been described that metformin administration has beneficial effects on different neurological conditions. In this work, we review the beneficial effects of this drug as a neuroprotective agent in different neurological diseases, with a special focus on epileptic disorders and Lafora disease, a particular type of progressive myoclonus epilepsy. In addition, we review the different proposed mechanisms of action of metformin to understand its function at the neurological level.

Mangiferin protects against alcoholic liver injury via suppression of inflammation-induced adipose hyperlipolysis

Adipose dysfunction is closely associated with alcoholic liver disease. The impact of mangiferin on ethanol-induced liver injury and the probable underlying molecular mechanism has not been sufficiently addressed. In the present study, mice were subjected to a chronic plus a single binge ethanol feeding to induce liver injury. In addition, the differentiated adipocytes from primary mouse adipocytes were isolated and used for the mechanism studies. Our study demonstrated that mangiferin protects against ethanol induced adipose hyperlipolysis by restoring PDE3B stability, which is associated with activating the AMPK/TBK1 signaling and suppressing the noncanonical NF-κB activation, leading to the reduction of free fatty acid release and the amelioration of ethanol-induced liver injury. Our findings identify that mangiferin ameliorates alcoholic liver injury via suppression of inflammation-induced adipose hyperlipolysis, suggesting that mangiferin might be a potential effective agent for the management of alcoholic liver injury.

Sildenafil Alleviates Murine Experimental Autoimmune Encephalomyelitis by Triggering Autophagy in the Spinal Cord

Multiple Sclerosis (MS) is a neuroinflammatory and chronic Central Nervous System (CNS) disease that affects millions of people worldwide. The search for more promising drugs for the treatment of MS has led to studies on Sildenafil, a phosphodiesterase type 5 Inhibitor (PDE5I) that has been shown to possess neuroprotective effects in the Experimental Autoimmune Encephalomyelitis (EAE), an animal model of MS. We have previously shown that Sildenafil improves the clinical score of EAE mice via modulation of apoptotic pathways, but other signaling pathways were not previously covered. Therefore, the aim of the present study was to further investigate the effects of Sildenafil treatment on autophagy and nitrosative stress signaling pathways in EAE. 24 female C57BL/6 mice were divided into the following groups: (A) Control - received only water; (B) EAE - EAE untreated mice; (C) SILD - EAE mice treated with 25mg/kg of Sildenafil s.c. The results showed that EAE mice presented a pro-nitrosative profile characterized by high tissue nitrite levels, lowered levels of p-eNOS and high levels of iNOS. Furthermore, decreased levels of LC3, beclin-1 and ATG5, suggests impaired autophagy, and decreased levels of AMPK in the spinal cord were also detected in EAE mice. Surprisingly, treatment with Sildenafil inhibited nitrosative stress and augmented the levels of LC3, beclin-1, ATG5, p-CREB and BDNF and decreased mTOR levels, as well as augmented p-AMPK. In conclusion, we propose that Sildenafil alleviates EAE by activating autophagy via the eNOS-NO-AMPK-mTOR-LC3-beclin1-ATG5 and eNOS-NO-AMPK-mTOR-CREB-BDNF pathways in the spinal cord.

Vitex negundo Linn. extract alleviates inflammatory aggravation and lung injury by modulating AMPK/PI3K/Akt/p38-NF-κB and TGF-β/Smad/Bcl2/caspase/LC3 cascade and macrophages activation in murine model of OVA-LPS induced allergic asthma

ETHNOPHARMACOLOGICAL RELEVANCE

There is growing inclination towards developing bioactive molecule-based strategies for the management of allergic airway inflammation associated respiratory diseases. Vitex negundo Linn., also known as Nirgundi, is one such medicinal plant enriched with phytochemicals and used for inflammatory and respiratory disorders including asthma in traditional system of medicine. Preliminary studies have claimed anti-tussive and bronchodilator potential of V. negundo Linn. However, its attributes as well as molecular mechanism (s) in modulation of asthma mediated by allergic inflammation are yet to be delineated scientifically.

AIM OF THE STUDY

Present study attempted to assess the effectiveness of Vitex negundo leaf extract (VNLE) in mitigation of allergen induced inflammation associated asthmatic lung damage with emphasis to delineate its molecular mechanism (s).

MATERIALS AND METHODS

Allergic lung inflammation was established in Balb/c mice using Ovalbumin-lipopolysaccharide (OVA-LPS). Several allergic inflammatory parameters, histopathological changes, alveolar macrophage activation and signalling pathways were assessed to examine protective effects of VNLE. UHPLC-DAD-QTOF-ESI-IMS was used to characterize VLNE.

RESULTS

VNLE administration effectively attenuated LPS-induced oxi-inflammatory stress in macrophages suggesting its anti-inflammatory potential. Further, VNLE showed protective effect in mitigating asthmatic lung damage as evident by reversal of pathological changes including inflammatory cell influx, congestion, fibrosis, bronchial thickness and alveolar collapse observed in allergen group. VNLE suppressed expressions of inflammatory Th1/Th2 cytokines, chemokines, endopeptidases (MMPs), oxidative effector enzyme (iNOS), adhesion molecules, IL-4/IFN-γ release with simultaneous enhancement in levels of IL-10, IFN-γ, MUC3 and tight junction proteins. Subsequent mechanistic investigation revealed that OVA-LPS concomitantly enhanced phosphorylation of NF-κB, PI3K, Akt and p38MAPKs and downregulated AMPK which was categorically counteracted by VNLE treatment. VNLE also suppressed OVA-LPS induced fibrosis, apoptosis, autophagy and gap junction proteins which were affirmed by reduction in TGF-β, Smad2/3/4, Caspase9/3, Bax, LC3A/B, connexin 50, connexin 43 and enhancement in Bcl2 expression. Additionally, suppression of alveolar macrophage activation, inflammatory cells in blood and elevation of splenic CD8+T cells was demonstrated. UHPLC-DAD-QTOF-ESI-IMS revealed presence of iridoids glycoside and phenolics which might contribute these findings.

CONCLUSION

These findings confer protective effect of VNLE in attenuation of allergic lung inflammation and suggest that it could be considered as valuable medicinal source for developing safe natural therapeutics for mitigation of allergic inflammation during asthma.

To breathe or not to breathe: Understanding how oxygen sensing contributes to age-related phenotypes

Aging is characterized by a progressive loss of tissue integrity and functionality due to disrupted homeostasis. Molecular oxygen is pivotal to maintain tissue functions, and aerobic species have evolved a sophisticated sensing system to ensure proper oxygen supply and demand. It is not surprising that aberrations in oxygen and oxygen-associated pathways subvert health and promote different aspects of aging. In this review, we discuss emerging findings on how oxygen-sensing mechanisms regulate different cellular and molecular processes during normal physiology, and how dysregulation of oxygen availability lead to disease and aging. We describe various clinical manifestations associated with deregulation of oxygen balance, and how oxygen-modulating therapies and natural oxygen oscillations influence longevity. We conclude by discussing how a better understanding of oxygen-related mechanisms that orchestrate aging processes may lead to the development of new therapeutic strategies to extend healthy aging.

Feed-forward regulation between cellular senescence and immunosuppression promotes the aging process and age-related diseases

Aging is a progressive degenerative process involving a chronic low-grade inflammation and the accumulation of senescent cells. One major issue is to reveal the mechanisms which promote the deposition of pro-inflammatory senescent cells within tissues. The accumulation involves mechanisms which increase cellular senescence as well as those inhibiting the clearance of senescent cells from tissues. It is known that a persistent inflammatory state evokes a compensatory immunosuppression which inhibits pro-inflammatory processes by impairing the functions of effector immune cells, e.g., macrophages, T cells and natural killer (NK) cells. Unfortunately, these cells are indispensable for immune surveillance and the subsequent clearance of senescent cells, i.e., the inflammation-induced counteracting immunosuppression prevents the cleansing of host tissues. Moreover, senescent cells can also repress their own clearance by expressing inhibitors of immune surveillance and releasing the ligands of NKG2D receptors which impair their surveillance by NK and cytotoxic CD8⁺ T cells. It seems that cellular senescence and immunosuppression establish a feed-forward process which promotes the aging process and age-related diseases. I will examine in detail the immunosuppressive mechanisms which impair the surveillance and clearance of pro-inflammatory senescent cells with aging. In addition, I will discuss several therapeutic strategies to halt the degenerative feed-forward circuit associated with the aging process and age-related diseases.

Ameliorative Effect of Dietary Tryptophan on Neurodegeneration and Inflammation in d-Galactose-Induced Aging Mice with the Potential Mechanism Relying on AMPK/SIRT1/PGC-1α Pathway and Gut Microbiota

Dietary tryptophan affects intestinal homeostasis and neurogenesis, whereas the underlying mechanism and the reciprocal interaction between tryptophan and gut microbiota in aging are unclear. This investigation was performed to determine the effect and mechanism of tryptophan on intestinal- and neuro- health in aging. In present study, the 0.4% tryptophan diet significantly ameliorated the oxidative stress and inflammation in the aging mice, potentially through the regulation of 5'-adenosine monophosphate (AMP)-activated protein kinase (AMPK) and nuclear factor κB (NF-κB) pathways. The 0.4% tryptophan diet increased the levels of indoles in colon contents, which indicated the potential contribution of tryptophan metabolites. Microbiome analysis revealed that the 0.4% tryptophan diet raised the relative abundance of Akkermansia in aging. The ameliorated effect of 0.4% tryptophan on neurodegeneration and neuroinflammation was summarized to potentially rely on the brain-derived neurotrophic factor- (BDNF) and NF-κB-related pathways. These findings provide the research evidence for the beneficial effect of tryptophan on aging.

AMPK and its Activator Berberine in the Treatment of Neurodegenerative Diseases

Neurodegenerative disorders are heterogeneous diseases associated with either acute or progressive neurodegeneration, causing the loss of neurons and axons in the central nervous system (CNS), showing high morbidity and mortality, and there are only a few effective therapies. Here, we summarized that the energy sensor adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), and its agonist berberine can combat the common underlying pathological events of neurodegeneration, including oxidative stress, neuroinflammation, mitochondrial disorder, glutamate excitotoxicity, apoptosis, autophagy disorder, and disruption of neurovascular units. The abovementioned effects of berberine may primarily depend on activating AMPK and its downstream targets, such as the mammalian target of rapamycin (mTOR), sirtuin1 (SIRT1), nuclear factor erythroid-2 related factor-2 (Nrf2), nuclear factor-κB (NF-κB), phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), nicotinamide adenine dinucleotide (NAD+), and p38 mitogen-activated protein kinase (p38 MAPK). It is hoped that this review will provide a strong basis for further scientific exploration and development of berberine's therapeutic potential against neurodegeneration.

Promising drug discovery strategies for sirtuin modulators: what lessons have we learnt?

INTRODUCTION

Sirtuins, NAD-dependent protein deacetylases, require NAD⁺ for enzymatic activity. Recent research has indicated that sirtuins have a key role in the regulation of gene expression, the cell cycle, apoptosis, neurodegeneration and several age-related diseases. In mammals, there are seven sirtuin isoforms (SIRT-1-7) that catalyze specific lysine substrate deacetylation.

AREAS COVERED

This review explains the current information on the structure, function and importance of sirtuin modulators. It also explores the possible therapeutic applications of sirtuin modulators and related small molecules in the context of various diseases.

EXPERT OPINION

Sirtuin's modulators open a new area of research for targeting pathological conditions. Sirtuin modulators, through their targeted function, may provide a possible tool for the amelioration of various diseases. However, the search of activators/inhibitors for sirtuins needs further research. The structural elucidation of sirtuins will create an understanding for the development of isoform-specific selective modulators. This could be a useful tool to determine the functions of individual sirtuins as potential therapeutic agents.

Valdecoxib improves lipid-induced skeletal muscle insulin resistance via simultaneous suppression of inflammation and endoplasmic reticulum stress

Valdecoxib (VAL), a non-steroidal anti-inflammatory drug, has been widely used for treatment of rheumatoid arthritis, osteoarthritis, and menstrual pain. It is a selective cyclooxygenase-2 inhibitor. The suppressive effects of VAL on cardiovascular diseases and neuroinflammation have been documented; however, its impact on insulin signaling in skeletal muscle has not been studied in detail. The aim of this study was to investigate the effects of VAL on insulin resistance in mouse skeletal muscle. Treatment of C2C12 myocytes with VAL reversed palmitate-induced aggravation of insulin signaling and glucose uptake. Further, VAL attenuated palmitate-induced inflammation and endoplasmic reticulum (ER) stress in a concentration-dependent manner. Treatment with VAL concentration-dependently upregulated AMP-activated protein kinase (AMPK) and heat shock protein beta 1 (HSPB1) expression. In line with in vitro experiments, treatment with VAL augmented AMPK phosphorylation and HSPB1 expression, thereby alleviating high-fat diet-induced insulin resistance along with inflammation and ER stress in mouse skeletal muscle. However, small interfering RNA-mediated inhibition of AMPK abolished the effects of VAL on insulin resistance, inflammation, and ER stress. These results suggest that VAL alleviates insulin resistance through AMPK/HSPB1-mediated inhibition of inflammation and ER stress in skeletal muscle under hyperlipidemic conditions. Hence, VAL could be used as an effective pharmacotherapeutic agent for management of insulin resistance and type 2 diabetes.

Selective AMPK activator leads to unfolded protein response downregulation and induces breast cancer cell death and autophagy

AIMS

AMPK plays a critical role regulating cell metabolism, growth and survival. Interfering with this enzyme activity has been extensively studied as putative mechanism for cancer therapy. The present work aims to identify a specific AMPK activator for cancer cells among a series of novel heterocyclic compounds.

MATERIALS AND METHODS

A series of novel hybrid heterocyclic compounds, namely naphtoquinone-4-oxoquinoline and isoquinoline-5,8-quinone-4-oxoquinoline derivatives, were synthesized via Michael reaction and their structures confirmed by spectral data: infrared; ¹H and ¹³C NMR spectroscopy (COSY, HSQC, HMBC); and high-resolution mass spectrometry (HRMS). The novel compounds were screened and tested for antitumoral activity and have part of their mechanism of action scrutinized.

KEY FINDINGS

Here, we identified a selective AMPK activator among the new hybrid heterocyclic compounds. This new compound presents selective cytotoxicity on breast cancer cells but not on non-cancer counterparts. We identified that by specifically activating AMPK in cancer cells, the drug downregulates unfolded protein response pathway, as well as inhibits mTOR signaling.

SIGNIFICANCE

These effects, that are selective for cancer cells, lead to activation of autophagy and, ultimately, to cancer cells death. Taken together, our data support the promising anticancer activity of this novel compound which is a strong modulator of metabolism.

Therapeutic potential of quercetin in an animal model of PCOS: Possible involvement of AMPK/SIRT-1 axis

Polycystic ovary syndrome is a common endocrine disorder worldwide. Recently, quercetin has been extensively investigated as a therapeutic option in patients with PCOS. Therefore, this study aimed to investigate the mechanisms underlying quercetin's positive effects by modulating key components of energy homeostasis and adipose tissue hormones in rats with letrozole-induced PCOS. Eighteen female Wistar rats were divided into three groups including control group (received carboxy methylcellulose (CMC 0.5%)), letrozole-induced PCOS ± quercetin group (received 1 mg/kg letrozole in CMC 0.5%), and letrozole-induced PCOS +/+ quercetin group (received same dose of letrozole + 100 mg/kg quercetin in CMC 0.5%). The estrous cycle, biochemical and hormonal parameters, as well as insulin resistance (IR) were evaluated in all groups. Western blotting was used to assess the expression levels of sirtuin-1 (SIRT-1), 5' AMP-activated protein kinase (AMPK), and adiponectin in target tissues of rats. The expression levels of visfatin and resistin were also evaluated through Real-time polymerase chain reaction (PCR). Treatment with quercetin improved the PCOS related disturbances in estrous cycle, lipid profile, serum levels of testosterone, estradiol and progesterone, and IR. Besides, the expression levels of AMPK and SIRT-1 in ovarian tissue were upregulated in the rats which received quercetin. Quercetin also reversed the PCOS-induced alteration in adipose tissue levels of adiponectin, visfatin, and resistin. Modulation of energy homeostasis through key components involved in this axis, as well as regulation of hormones releasing from adipose tissue may be the main underlying mechanisms for positive effects of quercetin in PCOS.

The Roles and Pharmacological Effects of FGF21 in Preventing Aging-Associated Metabolic Diseases

With the continuous improvement of living standards but the lack of exercise, aging-associated metabolic diseases such as obesity, type 2 diabetes mellitus (T2DM), and non-alcoholic fatty liver disease (NAFLD) are becoming a lingering dark cloud over society. Studies have found that metabolic disorders are near related to glucose, lipid metabolism, and cellular aging. Fibroblast growth factor 21 (FGF21), a member of the FGFs family, efficiently regulates the homeostasis of metabolism and cellular aging. By activating autophagy genes and improving inflammation, FGF21 indirectly delays cellular aging and directly exerts anti-aging effects by regulating aging genes. FGF21 can also regulate glucose and lipid metabolism by controlling metabolism-related genes, such as adipose triglyceride lipase (ATGL) and acetyl-CoA carboxylase (ACC1). Because FGF21 can regulate metabolism and cellular aging simultaneously, FGF21 analogs and FGF21 receptor agonists are gradually being valued and could become a treatment approach for aging-associated metabolic diseases. However, the mechanism by which FGF21 achieves curative effects is still not known. This review aims to interpret the interactive influence between FGF21, aging, and metabolic diseases and delineate the pharmacology of FGF21, providing theoretical support for further research on FGF21.

The role of autophagy in metal-induced urogenital carcinogenesis

Environmental and/or occupational exposure to metals such as Arsenic (As), Cadmium (Cd), and Chromium (Cr) have been shown to induce carcinogenesis in various organs, including the urogenital system. However, the mechanisms responsible for metal-induced carcinogenesis remain elusive. We and others have shown that metals are potent inducers of autophagy, which has been suggested to be an adaptive stress response to allow metal-exposed cells to survive in hostile environments. Albeit few, recent experimental studies have shown that As and Cd promote tumorigenesis via autophagy and that inhibition of autophagic signaling suppressed metal-induced carcinogenesis. In light of the newly emerging role of autophagic involvement in metal-induced carcinogenesis, the present review focuses explicitly on the mechanistic role of autophagy and potential signaling pathways involved in As-, Cd-, and Cr-induced urogenital carcinogenesis.

The AMPK modulator metformin as adjunct to methotrexate in patients with rheumatoid arthritis: A proof-of-concept, randomized, double-blind, placebo-controlled trial

BACKGROUND

Metformin (MET) may exert anti-rheumatic effects and reduce cartilage degradation through its immunomodulatory and anti-inflammatory actions.

METHODS

This was a double-blind placebo-controlled study, 120 adult patients with active rheumatoid arthritis (RA) were randomized to receive MET (1000 mg) or placebo daily with methotrexate (MTX, 7.5 mg/week) for 12 weeks. American College of Rheumatology (ACR)20, ACR50, and ACR70 response rates, Disease Activity Score in 28 joints (DAS-28), and drug safety were the efficacy endpoints. Serum levels of TNF-α, IL-1β, IL-6, IL-10, IL-17A, NF-κB, TGG-β1, MDA together with gene expression of AMPK and IGF-IR were assessed before and after the therapy.

RESULTS

A total of 80.8% of the patients in the MET group, compared with 54.7% in placebo group, met the criteria of ACR20 response after 12 weeks (P = 0.001). Statistically significant enhancements in the DAS28-3 (CRP) were observed after 4 and 8 weeks for the MET group compared with placebo and were sustained after 12 weeks. MET group showed statistically significant increase in percentage of patients achieving DAS remission after 12 weeks (P = 0.015). Significant improvements in ACR50, ACR70, Health Assessment Questionnaire Disability Index (HAQ-DI), and DAS28-3 (CRP) were also reported. MET was well-tolerated, and no serious adverse effects were reported in both groups. Furthermore, the MET group was superior in improving the measured parameters compared to the placebo.

CONCLUSIONS

MET improved the anti-rheumatic effect of MTX; suggesting it to be a beneficial adjuvant in patients with RA. Trial registration ID: NCT04068246.

LKB1 up-regulation inhibits hypothalamic inflammation and attenuates diet-induced obesity in mice

BACKGROUND

Diet-induced obesity (DIO) is associated with chronic, low-grade inflammation in the hypothalamus. The inflammatory pathway of the hypothalamus is activated during obesity, and inhibition of activation of the inflammatory pathway can partially reverse obesity. Therefore, exploring new targets for inhibiting hypothalamic inflammation will provide new ideas for the prevention and treatment of obesity. Liver kinase B1 (LKB1), a serine/threonine kinase, is a tumor suppressor and metabolic regulator. Recent studies have shown that LKB1 has a certain anti-inflammatory effect. However, a role of LKB1 in the regulation of hypothalamic inflammation remains unclear. Therefore, we examined whether LKB1 overexpression in the hypothalamus could weaken the hypothalamic inflammation and inhibit the development of obesity.

METHODS

LKB1 overexpressing adeno-associated virus (AAV) particles were injected stereotactically into the third ventricle (3 V) of C57BL/6 mice fed with HFD. We assessed changes in body mass and adiposity, food intake, hypothalamic inflammatory markers, and energy and glucose metabolism.

RESULTS

LKB1 up-regulation in hypothalamus attenuated diet-induced hypothalamic inflammation, reduced food intake and body weight gain. In addition, the overexpression of hypothalamic LKB1 increased the insulin sensitivity and improved whole-body lipid metabolism, which attenuated hepatic fat accumulation and serum lipid levels.

CONCLUSION

Hypothalamic LKB1 up-regulation attenuates hypothalamic inflammation, and protects against hypothalamic inflammation induced damage to melanocortin system, resulting in lower food intake and lower fat mass accumulation, which consequently protects mice from the development of obesity. Our data suggest LKB1 as a novel negative regulator of hypothalamic inflammation, and also a potentially important target for treating other inflammatory diseases.

A Fbxo48 inhibitor prevents pAMPKα degradation and ameliorates insulin resistance

The adenosine monophosphate (AMP)-activated protein kinase (Ampk) is a central regulator of metabolic pathways, and increasing Ampk activity has been considered to be an attractive therapeutic target. Here, we have identified an orphan ubiquitin E3 ligase subunit protein, Fbxo48, that targets the active, phosphorylated Ampkα (pAmpkα) for polyubiquitylation and proteasomal degradation. We have generated a novel Fbxo48 inhibitory compound, BC1618, whose potency in stimulating Ampk-dependent signaling greatly exceeds 5-aminoimidazole-4-carboxamide-1-β-ribofuranoside (AICAR) or metformin. This compound increases the biological activity of Ampk not by stimulating the activation of Ampk, but rather by preventing activated pAmpkα from Fbxo48-mediated degradation. We demonstrate that, consistent with augmenting Ampk activity, BC1618 promotes mitochondrial fission, facilitates autophagy and improves hepatic insulin sensitivity in high-fat-diet-induced obese mice. Hence, we provide a unique bioactive compound that inhibits pAmpkα disposal. Together, these results define a new pathway regulating Ampk biological activity and demonstrate the potential utility of modulating this pathway for therapeutic benefit.

Alismatis Rhizoma Triterpenes Alleviate High-Fat Diet-Induced Insulin Resistance in Skeletal Muscle of Mice

Alismatis rhizoma (AR), which is the dried rhizome of Alisma orientale (Sam.) Juz. (Alismataceae), is an important component of many famous Chinese formulas for hypoglycemic. This study aimed to evaluate the insulin resistance (IR) alleviating effects of AR triterpenes (ART) and ART component compatibility (ARTC, the mixture of 16-oxo-alisol A, 16-oxo-alisol A 23-acetate, 16-oxo-alisol A 24-acetate, alisol C, alisol C 23-acetate, alisol L, alisol A, alisol A 23-acetate, alisol A 24-acetate, alisol L 23-acetate, alisol B, alisol B 23-acetate, 11-deoxy-alisol B and 11-deoxy-alisol B 23-acetate) in high-fat diet-induced IR mice and plamitate-treated IR C2C12 cells, respectively. A dose of 200 mg/kg of ART was orally administered to IR mice, and different doses (25, 50, and 100 μg/ml) of ARTC groups were treated to IR C2C12 cells. IPGTT, IPITT, body weight, Hb1AC, FFA, TNF-α, MCP-1, and IR-associated gene expression (p-AMPK, p-IRS-1, PI3K, p-AKT, p-JNK, and GLUT4) were measured in IR mice. Glucose uptake, TNF-α, MCP-1, and IR-associated gene expression were also measured in IR C2C12 cells. Results showed that ART alleviated high-fat diet-induced IR in the skeletal muscle of mice, and this finding was further validated by ARTC. This study demonstrated that ART presented a notable IR alleviating effect by regulating IR-associated gene expression, and triterpenes were the material basis for the IR alleviating activity of AR.

NQO1 mediates the anti-inflammatory effects of nootkatone in lipopolysaccharide-induced neuroinflammation by modulating the AMPK signaling pathway

Neuroinflammation and oxidative stress play key roles in the progression of neurodegenerative diseases. Thus, the use of potent anti-inflammatory/antioxidant agents has been suggested as a promising therapeutic strategy for neurodegenerative diseases. In the present study, we investigated the anti-inflammatory and antioxidant effects of nootkatone (NKT), a sesquiterpenoid compound isolated from grapefruit, in in vitro and in vivo models of neuroinflammation. In lipopolysaccharide (LPS)-stimulated BV2 microglial cells, NKT inhibited the expression of iNOS, COX-2, and pro-inflammatory cytokines, and increased the expression of the anti-inflammatory cytokine, IL-10. In addition, NKT inhibited reactive oxygen species (ROS) production and upregulated the expression of antioxidant enzymes, such as NQO1 and HO-1. Molecular mechanistic studies showed that NKT inhibited Akt, p38 MAPK, and NF-κB activities, while increasing AMPK, PKA/CREB, and Nrf2/ARE signaling in LPS-stimulated BV2 cells. Since NKT dramatically increased NQO1 expression, we investigated the role of this enzyme using pharmacological inhibition or knockdown experiments. Treatment of BV2 cells with the NQO1-specific inhibitor, dicoumarol, or with NQO1 siRNA significantly blocked NKT-mediated inhibition of NO, ROS, TNF-α, IL-1β, and upregulation of IL-10. Furthermore, NQO1 inhibition reversed the effects of NKT on pro- and anti-inflammatory signaling molecules. Intriguingly, we found that the AMPK inhibitor, compound C, mimicked the effects of dicoumarol, suggesting the presence of a crosstalk between NQO1 and AMPK. Finally, we demonstrated that NKT inhibited microglial activation, lipid peroxidation, and the expression of pro-inflammatory markers in the brains of LPS-injected mice, which was also reversed by dicoumarol. These data collectively suggest that NQO1 plays a critical role in mediating the anti-inflammatory and antioxidant effects of NKT in LPS-induced neuroinflammation by modulating AMPK and its downstream signaling pathways.