Sodium salicylate modulates inflammatory responses through AMP-activated protein kinase activation in LPS-stimulated THP-1 cells

Beneficial effect of metformin on tolerance to analgesic effects of sodium salicylate in male rats

Background

Tolerance to the analgesic effects of opioids and non-steroidal anti-inflammatory drugs (NSAIDs) is a major concern for relieving pain. Thus, it is highly valuable to find new pharmacological strategies for prolonged therapeutic procedures. Biguanide-type drugs such as metformin (MET) are effective for neuroprotection and can be beneficial for addressing opioid tolerance in the treatment of chronic pain. It has been proposed that analgesic tolerance to NSAIDs is mediated by the endogenous opioid system. According to the cross-tolerance between NSAIDs, especially sodium salicylate (SS), and opiates, especially morphine, the objective of this study was to investigate whether MET administration can reduce tolerance to the anti-nociceptive effects of SS.

Methods

Fifty-six male Wistar rats were used in this research (weight 200-250 g). For induction of tolerance, SS (300 mg/kg) was injected intraperitoneally for 7 days. During the examination period, animals received MET at doses of 50, 75, or 100 mg/kg for 7 days to evaluate the development of tolerance to the analgesic effect of SS. The hot plate test was used to evaluate the drugs' anti-nociceptive properties.

Results

Salicylate injection significantly increased hot plate latency as compared to the control group, but the total analgesic effect of co-treatment with SS + Met50 was stronger than the SS group. Furthermore, the effect of this combination undergoes less analgesic tolerance over time.

Conclusions

It can be concluded that MET can reduce the analgesic tolerance that is induced by repeated intraperitoneal injections of SS in Wister rats.

Antioxidant activity and metabolic regulation of sodium salicylate on goat sperm at low temperature

OBJECTIVE

The purpose of this study was to explore the effect of sodium salicylate (SS) on semen preservation and metabolic regulation in goats.

METHODS

Under the condition of low temperature, SS was added to goat semen diluent to detect goat sperm motility, plasma membrane, acrosome, antioxidant capacity, mitochondrial membrane potential (MMP) and metabonomics.

RESULTS

The results show that at the 8th day of low-temperature storage, the sperm motility of the 20 μM SS group was 66.64%, and the integrity rates of the plasma membrane and acrosome were both above 60%, significantly higher than those of the other groups. The activities of catalase and superoxide dismutase in the sperm of the 20 μM SS group were significantly higher than those of the control group, the contents of reactive oxygen species and malondialdehyde were significantly lower than those in the control group, the MMP was significantly higher than that in the control group, and the contents of Ca2+ and total cholesterol were significantly higher than those in the control group. Through metabonomics analysis, there were significant metabolic differences between the control group and the 20 μM SS group. Twenty of the most significant metabolic markers were screened, mainly involving five metabolic pathways, of which nicotinic acid and nicotinamide metabolic pathways were the most significant.

CONCLUSION

The results indicate that SS can effectively improve the low-temperature preservation quality of goat sperm.

Sodium salicylate ameliorates exercise-induced muscle damage in mice by inhibiting NF-kB signaling

BACKGROUND

Eccentric muscle contraction can cause muscle damage, which reduces the efficiency of exercise. Previous evidence suggested that Sodium salicylate (SS) could improve the repair of aged muscle. This study intends to investigate whether SS can impact skeletal muscle damage caused by eccentric exercise.

METHODS

Eccentric treadmill exercise was performed to induce muscle damage in mice. Plasma levels of muscle damage markers were estimated. RT-qPCR was employed for detecting mRNA levels of proinflammatory mediators in murine gastrocnemius muscle. Immunofluorescence staining of laminin/DAPI was utilized for quantifying centrally nucleated myofibers in the gastrocnemius muscle. Western blotting was implemented to examine protein levels of mitsugumin 53 (MG53), matrix metalloproteinase (MMP)-2/9, and NF-κB signaling-related markers.

RESULTS

SS administration reduced muscle damage marker production in the plasma and decreased the levels of proinflammatory mediators, MG53 and MMP-2/9 in mice after exercise. SS alleviated the severity of muscle damage in the gastrocnemius of mice after eccentric exercise. SS blocked NF-κB signaling pathway in the gastrocnemius muscle.

CONCLUSION

SS administration ameliorates skeletal muscle damage caused by eccentric exercise in the mouse model.

Comparative structural study of selective and non-selective NSAIDs against the enzyme cyclooxygenase-2 through real-time molecular dynamics linked to post-dynamics MM-GBSA and e-pharmacophores mapping

BACKGROUND

Inflammation-provoked disorders including cancer are arbitrated by cyclooxygenase-2 (COX-2). Celecoxib and niflumic acid are among the potent and selective inhibitors of this enzyme while aspirin (acetylsalicylic acid) and sodium salicylate are its non-selective and lesser potent inhibitors. Despite these proven studies, the comparative structural study of these selective and non-selective molecules at atomistic scale in complex state with COX-2 that may answer this differential inhibitory behavior has not been accomplished spotlighting the imperative need of additional research in this area. Thus, this study was framed to provide a strong explanation for the enigma of higher inhibitory activity of celecoxib-niflumic acid duo in comparison to aspirin and sodium salicylate towards COX-2.

METHODS

A contemporary approach including advanced molecular docking against COX2, molecular dynamics of receptor-ligand complexes, simulation-trajectory-backed MMGBSA for different time points, radius of gyration (Rg) calculations, and e-pharmacophores approach was employed to attain a rational conclusion.

RESULTS

Our findings demonstrated the higher binding affinity of celecoxib and niflumic acid over aspirin and sodium salicylate against COX-2. Although both selective and non-selective COX-2 inhibitors manifested nearly the same stability in the active site of this enzyme but the e-pharmocophoric features found in the case of selective inhibitors scored over non-selective ones. Thus, our findings excluded the differential stability to be the cause of stronger potency of selective inhibitors but attributed their potency to greater number of complementary features present in these inhibitors against the active site of inflammation engendering COX-2.

Sodium Salicylate as Feed Additive in Broilers: Absence of Toxicopathological Findings

Antimicrobial growth promoters (AGPs) in animal production have been related to the increase in multidrug-resistant bacteria. The AGP ban in many countries has highlighted the growing need for alternatives for feed additives. Considering the non-antibiotic anti-inflammatory theory of AGPs, chicks received three different doses of sodium salicylate (SS) in feed (10, 30, 90 mg/kg), basal diet (BD) was used as a negative control, and zinc bacitracin (ZB) was used as a positive control. Chicks were individually housed to increase the accuracy of the dose of SS ingested. Performance parameters and footpad dermatitis were evaluated weekly, while haematology, serum biochemistry, histopathology, and tibial dyschondroplasia were determined on Days 21 and 42. A linear dose-dependent decrease in haemoglobin concentration was observed, but the values were within the normal reference range. Among all the other evaluated parameters, no relevant differences between treatments were observed; however, not even the AGP group performed better than the control group. It is possible that the conditions in which the birds were raised were not stressful enough to allow for anti-inflammatories to demonstrate their beneficial effects on performance. Studies should be conducted where the animals are exposed to commercial conditions, as the presence of natural stressors could allow a better evaluation of the efficacy of the anti-inflammatory agent as a growth promoter.

Metabolite, protein, and tissue dysfunction associated with COVID-19 disease severity

Proteins are direct products of the genome and metabolites are functional products of interactions between the host and other factors such as environment, disease state, clinical information, etc. Omics data, including proteins and metabolites, are useful in characterizing biological processes underlying COVID-19 along with patient data and clinical information, yet few methods are available to effectively analyze such diverse and unstructured data. Using an integrated approach that combines proteomics and metabolomics data, we investigated the changes in metabolites and proteins in relation to patient characteristics (e.g., age, gender, and health outcome) and clinical information (e.g., metabolic panel and complete blood count test results). We found significant enrichment of biological indicators of lung, liver, and gastrointestinal dysfunction associated with disease severity using publicly available metabolite and protein profiles. Our analyses specifically identified enriched proteins that play a critical role in responses to injury or infection within these anatomical sites, but may contribute to excessive systemic inflammation within the context of COVID-19. Furthermore, we have used this information in conjunction with machine learning algorithms to predict the health status of patients presenting symptoms of COVID-19. This work provides a roadmap for understanding the biochemical pathways and molecular mechanisms that drive disease severity, progression, and treatment of COVID-19.

Limitations of drug concentrations used in cell culture studies for understanding clinical responses of NSAIDs

In this review, the in vitro cellular effects of six nonsteroidal anti-inflammatory drugs (NSAIDs), salicylate, ibuprofen, naproxen, indomethacin, celecoxib and diclofenac, are examined. Inhibition of prostanoid synthesis in vitro generally occurs within the therapeutic range of plasma concentrations that are observed in vivo, consistent with the major action of NSAIDs being inhibition of prostanoid production. An additional probable cellular action of NSAIDs has been discovered recently, viz. decreased oxidation of the endocannabinoids, 2-arachidonoyl glycerol and arachidonyl ethanolamide. Many effects of NSAIDs, other than decreased oxidation of arachidonic acid and endocannabinoids, have been put forward but almost all of these additional processes are observed at supratherapeutic concentrations when the concentration of albumin, the major protein that binds NSAIDs, is taken into account. However, one exception is salicylate, a very potent inhibitor of the neutrophilic enzyme, myeloperoxidase, the inhibition of which leads to reduced production of the inflammatory mediator, hypochlorous acid, and inhibition of the inflammation associated with rheumatoid arthritis.

Activation of AMPK suppresses S1P-induced airway smooth muscle cells proliferation and its potential mechanisms

The aims of the present study were to investigate the signaling mechanisms for sphingosine-1-phosphate (S1P)-induced airway smooth muscle cells (ASMCs) proliferation and to explore the effect of activation of adenosine monophosphate-activated protein kinase (AMPK) on S1P-induced ASMCs proliferation and its underlying mechanisms. S1P phosphorylated signal transducer and activator of transcription 3 (STAT3) through binding to S1PR_2/3, and this further sequentially up-regulated polo-like kinase 1 (PLK1) and inhibitor of differentiation 2 (ID2) protein expression. Pretreatment of cells with S1PR₂ antagonist JTE-013, S1PR₃ antagonist CAY-10444, knockdown of STAT3, PLK1 and ID2 attenuated S1P-triggered ASMCs proliferation. In addition, activation of AMPK by metformin inhibited S1P-induced ASMCs proliferation by suppressing STAT3 phosphorylation and therefore suppression of PLK1 and ID2 protein expression. Our study suggests that S1P promotes ASMCs proliferation by stimulating S1PR_2/3/STAT3/PLK1/ID2 axis, and activation of AMPK suppresses ASMCs proliferation by targeting on STAT3 signaling pathway. Activation of AMPK might benefit asthma by inhibiting airway remodeling.

Irisin induces trophoblast differentiation via AMPK activation in the human placenta

Irisin, an adipokine, regulates differentiation and phenotype in various cell types including myocytes, adipocytes, and osteoblasts. Circulating irisin concentration increases throughout human pregnancy. In pregnancy disorders such as preeclampsia and gestational diabetes mellitus, circulating irisin levels are reduced compared to healthy controls. To date, there are no data on the role and molecular function of irisin in the human placenta or its contribution to pathophysiology. Aberrant trophoblast differentiation is involved in the pathophysiology of preeclampsia. The current study aimed to assess the molecular effects of irisin on trophoblast differentiation and function. First-trimester placental explants were cultured and treated with low (10 nM) and high (50 nM) physiological doses of irisin. Treatment with irisin dose-dependently increased both in vitro placental outgrowth (on Matrigel™) and trophoblast cell-cell fusion. Adenosine monophosphate-activated protein kinase (AMPK) signaling, an important regulator of cellular energy homeostasis that is involved in trophoblast differentiation and pathology, was subsequently investigated. Here, irisin exposure induced placental AMPK activation. To determine the effects of irisin on trophoblast differentiation, two trophoblast-like cell lines, HTR-8/SVneo and BeWo, were treated with irisin and/or a specific AMPK inhibitor (Compound C). Irisin-induced AMPK phosphorylation in HTR-8/SVneo cells. Additionally, as part of the differentiation process, integrin switching from α6 to α1 occurred as well as increased invasiveness. Overall, irisin promoted differentiation in villous and extravillous cell-based models via AMPK pathway activation. These findings provide evidence that exposure to irisin promotes differentiation and improves trophoblast functions in the human placenta that are affected in abnormal placentation.

Astragalus membranaceus Injection Suppresses Production of Interleukin-6 by Activating Autophagy through the AMPK-mTOR Pathway in Lipopolysaccharide-Stimulated Macrophages

Astragalus membranaceus (AM), used in traditional Chinese medicine, has been shown to enhance immune functions, and recently, its anti-inflammatory effects were identified. However, the mechanisms of action remain unclear. Most studies have shown that autophagy might be involved in the immune response of the body, including inflammation. Here, we developed an inflammatory model by stimulating macrophages with lipopolysaccharides (LPS) to explore the anti-inflammatory effect and mechanisms of AM injection from the perspective of the regulation of autophagy. Immunoblot, immunofluorescence, and ELISA were used to determine the effects of AM injection on the production of interleukin-6 (IL-6) and alterations of autophagy markers. It was found that AM injection reduced the expression of IL-6 in LPS-stimulated macrophages and reversed the LPS-induced inhibition of cellular autophagy. After treatment with inhibitors of signaling pathways, it was shown that LPS downregulated autophagy and upregulated the production of IL-6 in macrophages via the protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway. AM injection reversed the effects of LPS by activating the AMP-activated protein kinase (AMPK) instead of inhibiting Akt. These results were further confirmed by testing activators and siRNA silencing of AMPK. Hence, these 2 distinct signaling molecules appear to exert opposite effects on mTOR, which integrates information from multiple upstream signaling pathways, negatively regulating autophagy. In addition, we demonstrated that autophagy might play a key role in regulating the production of IL-6 by testing activators and inhibitors of autophagy and siRNA silencing of ATG5. These findings showed that AM injection might enhance autophagy by activating AMPK and might further play a repressive effect on the LPS-stimulated expression of IL-6. This study explored the relationship between autophagy, signaling pathways, and the production of inflammatory factors in a model of endotoxin infection and treatment with AM injection.

Nrf2-SHP Cascade-Mediated STAT3 Inactivation Contributes to AMPK-Driven Protection Against Endotoxic Inflammation

Signal transducer and activator of transcription 3 (STAT3) is implicated in inflammation processing, but the mechanism of its regulation mostly remains limited to Janus kinase (JAK)-mediated phosphorylation. Although AMP-activated protein kinase (AMPK)-mediated STAT3 inactivation has got documented, the molecular signaling cascade connecting STAT3 inactivation and the anti-inflammatory role of AMPK is far from established. In the present study, we addressed the interplay between AMPK and STAT3, and revealed the important role of STAT3 inactivation in the anti-inflammatory function of AMPK in lipopolysaccharide-stressed macrophages and mice. Firstly, we found that pharmacological inhibition of STAT3 can improve the anti-inflammatory effect of AMPK in wild-type mice, and the expression of STAT3 in macrophage of mice is a prerequisite for the anti-inflammatory effect of AMPK. As to the molecular signaling cascade linking AMPK to STAT3, we disclosed that AMPK suppressed STAT3 not only by attenuating JAK signaling but also by activating nuclear factor erythroid-2-related factor-2 (Nrf2), a redox-regulating transcription factor, which consequently increased the expression of small heterodimer protein (SHP), thus repressing the transcriptional activity of STAT3. In summary, this study provided a unique set of evidence showing the relationship between AMPK and STAT3 signaling and explored a new mechanism of AMPK-driven STAT3 inactivation that involves Nrf2-SHP signaling cascade. These findings expand our understanding of the interplay between pro- and anti-inflammatory signaling pathways and are beneficial for the therapeutic development of sepsis treatments.

Physicochemical properties and laxative effects of polysaccharides from Anemarrhena asphodeloides Bge. in loperamide-induced rats

ETHNOPHARMACOLOGICAL RELEVANCE

As a traditional Chinese herbal medicine, Anemarrhena asphodeloides Bge. possesses the effects of nourishing yin, moistening dryness, clearing lungs and relieving fire. Simultaneously, it has been used to treat constipation for more than one thousand years in China. However, modern medical studies are limited and lacking on its therapeutic mechanism.

AIM OF THE STUDY

This current study was aimed to investigate the laxative activities and explore the potential mechanism of Anemarrhena asphodeloides Bge. polysaccharides (AABP) in loperamide-induced constipation rats.

MATERIALS AND METHODS

The structure of AABP was determined by using infrared spectrum, high performance gel permeation chromatography (HPGPC), and high performance liquid chromatography (HPLC). Real-time quantitative polymerase chain reaction (PCR), multitudinous methods were adopted to explore the underlining therapeutic mechanism of AABP in treating constipation, including enzyme-linked immunosorbent assay (ELISA), histopathological, immunohistochemistry and western blotting.

RESULTS

In the present study, the average molecular weight of AABP was determined as 1.11 × 10³ kDa. The primary monosaccharide compositions were analyzed including D-mannose, L-rhamnose, D-galacturonic acid, D-glucose, D-galactose and L-arabinose (1, 0.04, 0.53, 0.11, 0.33, 0.25, respectively) by high-performance liquid chromatography (HPLC). AABP significantly increased the levels of gastrin (Gas), motilin (MTL), substance P (SP), 5-hydroxytryptamine (5-HT) and vasoactive intestinal peptide (VIP), and decreased the NO content of loperamide-induced rats to ameliorate constipation in the rats. Whilst, AABP repaired the damaged colons by regulating PCNA and ICAM-1 protein expressions. Additionally, AABP up-regulated the levels of SCF, c-Kit, AQP3 and VIP as well as down-regulated the expressions of AQP8, AQP4 and PGE2.

CONCLUSION

The present findings suggested that AABP were the laxative active ingredients isolated from Anemarrhena asphodeloides Bge., which could treat constipation through regulating the gastrointestinal hormones and neurotransmitters to improve the intestinal motility and water metabolism.

Relationship of the Phytochemicals from Coffee and Cocoa By-Products with their Potential to Modulate Biomarkers of Metabolic Syndrome In Vitro

This study aimed to compare the phytochemicals from coffee and cocoa by-products and their relationship with the potential for reducing markers of inflammation, oxidative stress, adipogenesis, and insulin resistance in vitro. We characterized the phytochemical profile of extracts from coffee husk, coffee silverskin, and cocoa shell and evaluated their in vitro biological activity in RAW264.7 macrophages and 3T3-L1 adipocytes. Pearson correlations and principal component regressions were performed to find the contribution of phytochemicals and underlying mechanisms of action. Coffee husk and silverskin extracts were mainly composed of caffeine and chlorogenic acid. Major components in cocoa shell included theobromine and protocatechuic acid. Both coffee and cocoa by-product extracts effectively reduced inflammatory markers in macrophages and adipocytes (NO, PGE2, TNF-α, MCP-1, and IL-6) and the production of reactive oxygen species (21.5-66.4%). Protocatechuic and chlorogenic acids, together with caffeine, were suggested as main contributors against inflammation and oxidative stress. Furthermore, extracts reduced lipid accumulation (4.1-49.1%) in adipocytes by regulating lipolysis and inducing adipocyte browning. Gallic and chlorogenic acids were associated with reduced adipogenesis, and caffeine with adipocyte browning. Extracts from coffee and cocoa by-products also modulated the phosphorylation of insulin receptor signaling pathway and stimulated GLUT-4 translocation (52.4-72.9%), increasing glucose uptake. The insulin-sensitizing potential of the extracts was mainly associated with protocatechuic acid. For the first time, we identified the phytochemicals from coffee and cocoa by-products and offered new insights into their associations with biomarkers of inflammation, oxidative stress, adipogenesis, and insulin resistance in vitro.

The therapeutic effects of traditional Chinese medicine Fusu agent in LPS-induced acute lung injury model rats

Purpose

Acute lung injury (ALI) is a common and fatal oxidative stress in the lung, mainly induced by endothelial injury and capillary leakage. In our previous study, “Fusu agent”, a traditional Chinese medicine, was found to exert preventive effect on endothelial damage in lipopoly-saccharide (LPS)-induced ALI model rats partially via inhibiting heparanase1 (HPA1) activation and inhibiting the inflammatory factors. However, it is still unknown whether Fusu agent exerts its therapeutic effect in LPS-induced ALI model rats and its potential mechanism.

Materials and methods

Rats were injected with LPS (3 mg/kg, intraperitoneally) to induced ALI, and the prepared Fusu agent was given (2, 4 or 6 g/kg) 2 hours after LPS challenge. Twenty-four or 48 hours after Fusu agent administration, the biochemical changes in the plasma and lung tissues and the morphological/histological changes in the lung associated with inflammation and injury were evaluated. Human umbilical vein endothelial cells (HUVECs) were employed to confirm the therapeutic effects of Fusu agent and investigate its mechanisms, that is, affecting ROS accumulation, mitochondrial transmembrane potential (MTP) maintenance and decreasing the expression levels of HPA1.

Results

Administration of Fusu agent obviously improved the lung injury and recovered vascular endothelium loss and injury. CD31 signal, which is a specific marker for endothelial vascular lesions, was decreased after Fusu agent treatment in LPS-induced ALI model rats, indicating its therapeutic effect against endothelial surface layer injury. Meanwhile, Fusu agent also decreased HPA1 expression and inflammatory responses. In vitro, Fusu agent-medicated serum decreased injury and cell death induced by LPS in HUVECs by stabilizing MTP and decreasing the leakage of lactate dehydrogenase. Consistently, Fusu agent-medicated serum downregulated HPA1 induced by LPS stimulation.

Conclusion

These findings suggest that Fusu agent exerts its therapeutic effect in both LPS-induced ALI model rats and HUVECs potentially via suppressing HPA1 expression, and thus exerts prosurvival effect via maintaining MTP and attenuating cell injury.

Nuciferine Inhibits Proinflammatory Cytokines via the PPARs in LPS-Induced RAW264.7 Cells

Inflammation is important and has been found to be an underlying cause in many acute and chronic human diseases. Nuciferine, a natural alkaloid containing an aromatic ring, is found in the nelumbo nucifera leaves. It has been shown to have potential anti-inflammatory activities, but the molecular mechanism has remained unclear. In this study, we found that nuciferine (10 μM) significantly inhibited the lipopolysaccharide (LPS)-induced inflammatory cytokine IL-6 and TNF-α production in RAW 264.7 cells. In addition, the luciferase reporter assay results of different subtypes of the peroxisome proliferator-activated receptor (PPAR) showed that nuciferine dose-dependently activated all the PPAR activities. Specific inhibitors of PPARα and PPARγ significantly abolished the production of inflammatory cytokines as well as IκBα degradation. However, PPARδ inhibitor did not show this effect. Our results suggested a potential molecular mechanism of the anti-inflammatory effects of nuciferine in LPS-induced inflammation, at least in part, by activating PPARα and PPARγ in RAW 264.7 cells.

BRF1 ameliorates LPS-induced inflammation through autophagy crosstalking with MAPK/ERK signaling

Inflammation is indispensable for host defense, whereas excessive inflammation often develop inflammatory diseases. Autophagy is thought to be engaged in many extracellular stress responses, such as starvation and innate immunity. Thus, autophagy plays an important role in maintaining homeostasis. The purpose of this study was to elucidate the function of BRF1 in the regulation of inflammation and autophagy response in macrophages. We found that BRF1 inhibited the LPS-induced inflammatory factors expression and the autophagy flux in macrophage. Furthermore, inhibition autophagy with 3-MA can attenuate the suppressive effect of BRF1 on LPS-mediated inflammation. In addition, MAPK/ERK signaling pathway was involved in the BRF1 inhibition inflammation and autophagy in macrophages. These findings indicate that BRF1 attenuates LPS-induced inflammatory factors secretion through autophagy, at least in part, through MAPK/ERK signaling pathway.

HIV vaccine candidate activation of hypoxia and the inflammasome in CD14+ monocytes is associated with a decreased risk of SIVmac251 acquisition

Qualitative differences in the innate and adaptive responses elicited by different HIV vaccine candidates have not been thoroughly investigated. We tested the ability of the Aventis Pasteur live recombinant canarypox vector (ALVAC)-SIV, DNA-SIV and Ad26-SIV vaccine prime modalities together with two ALVAC-SIV + gp120 protein boosts to reduce the risk of SIVmac251 acquisition in rhesus macaques. We found that the DNA and ALVAC prime regimens were effective, but the Ad26 prime was not. The activation of hypoxia and the inflammasome in CD14+CD16- monocytes, gut-homing CCR5-negative CD4+ T helper 2 (TH2) cells and antibodies to variable region 2 correlated with a decreased risk of SIVmac251 acquisition. By contrast, signal transducer and activator of transcription 3 activation in CD16+ monocytes was associated with an increased risk of virus acquisition. The Ad26 prime regimen induced the accumulation of CX3CR1+CD163+ macrophages in lymph nodes and of long-lasting CD4+ TH17 cells in the gut and lungs. Our data indicate that the selective engagement of monocyte subsets following a vaccine prime influences long-term immunity, uncovering an unexpected association of CD14+ innate monocytes with a reduced risk of SIVmac251 acquisition.

Sodium salicylate modulates inflammatory responses through AMP-activated protein kinase activation in LPS-stimulated THP-1 cells

Sodium salicylate (NaSal) is a nonsteroidal anti-inflammatory drug. The putative mechanisms for NaSal's pharmacologic actions include the inhibition of cyclooxygenases, platelet-derived thromboxane A2, and NF-κB signaling. Recent studies demonstrated that salicylate could activate AMP-activated protein kinase (AMPK), an energy sensor that maintains the balance between ATP production and consumption. The anti-inflammatory action of AMPK has been reported to be mediated by promoting mitochondrial biogenesis and fatty acid oxidation. However, the exact signals responsible for salicylate-mediated inflammation through AMPK are not well-understood. In the current study, we examined the potential effects of NaSal on inflammation-like responses of THP-1 monocytes to lipopolysaccharide (LPS) challenge. THP-1 cells were stimulated with or without 10 ug/mL LPS for 24 h in the presence or absence of 5 mM NaSal. Apoptosis was measured by flow cytometry using Annexin V/PI staining and by Western blotting for the Bcl-2 anti-apoptotic protein. Cell proliferation was detected by EdU incorporation and by Western blot analysis for proliferating cell nuclear antigen (PCNA). Secretion of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) was determined by enzyme-linked immunosorbent assay (ELISA). We observed that the activation of AMPK by NaSal was accompanied by induction of apoptosis, inhibition of cell proliferation, and increasing secretion of TNF-α and IL-1β. These effects were reversed by Compound C, an inhibitor of AMPK. In addition, NaSal/AMPK activation inhibited LPS-induced STAT3 phosphorylation, which was reversed by Compound C treatment. We conclude that AMPK activation is important for NaSal-mediated inflammation by inducing apoptosis, reducing cell proliferation, inhibiting STAT3 activity, and producing TNF-α and IL-1β.