α-Mangostin Alleviated Lipopolysaccharide Induced Acute Lung Injury in Rats by Suppressing NAMPT/NAD Controlled Inflammatory Reactions

Palmatine Attenuated Lipopolysaccharide-Induced Acute Lung Injury by Inhibiting M1 Phenotype Macrophage Polarization via NAMPT/TLR2/CCR1 Signaling

The present work was conducted to research the potential mechanism of palmatine (PAL) on lipopolysaccharide (LPS)-caused acute lung injury (ALI). Network pharmacology and bioinformatic analyses were carried out. Mice were intragastrically treated with PAL and intratracheally stimulated with LPS. LPS-induced RAW264.7 cells were employed for the in vitro model. The MPO activity, W/D ratio, neutrophils, total cell number in BALF, and histopathological alteration were examined. The levels of TNF-α, IL-1β, IL-6, IL-18, IL-4, and IL-10 in serum, BALF, and supernatant were examined by ELISA. The mRNA expressions of iNOS, CD68, Arg1, Ym1, and CD206 and protein expressions of NAMPT, TLR2, CCR1, and NLRP3 inflammasome were detected by PCR, WB, and immunofluorescence. The NAMPT inhibitor FK866, TLR2 inhibitor C29, CCR1 inhibitor BX471, NAMPT-overexpression (OE) plasmid, and TLR2-OE plasmid were used for mechanism research. As a result, PAL relieved the symptoms of ALI. PAL inhibited M1 phenotype indices and promoted M2 phenotype indices in both LPS-induced mice and RAW264.7 cells. PAL also inhibited the expressions of NAMPT, TLR2, CCR1, and NLRP3 inflammasome. The treatments with FK866, NAMPT-OE plasmid, C29, TLR2-OE plasmid, and BX471 proved that PAL exerted its effect via NAMPT/TLR2/CCR1. Molecular docking suggested that PAL might combine with NAMPT. In conclusion, PAL ameliorated LPS-induced ALI by inhibiting M1 phenotype macrophage polarization via NAMPT/TLR2/CCR1 signaling.

α-Mangostin Treats Early-Stage Adjuvant-Induced Arthritis of Rat by Regulating the CAP-SIRT1 Pathway in Macrophages

Background

Studies have found that α-mangostin (MG) can relieve experimental arthritis by activating cholinergic anti-inflammatory pathway (CAP). It affects the polarization of macrophages and the balance of related immune cell subpopulations, but the specific mechanism is still unclear. It has been found that silent information regulator 1 (SIRT1) is closely related to macrophage activity. The purpose of this study is to explore the mechanism of MG intervening in macrophage polarization during treatment of early adjuvant-induced (AIA) rats through the CAP-SIRT1 pathway.

Methods

We investigated the polarization of M1 macrophages and the differentiation of Th1 in AIA rats by flow cytometry. Activity of acetylcholinesterase (AChE) and the level of nicotinic adenine dinucleotide (NAD+) in serum were also detected, and immunohistochemical was used to detect the levels of α7 nicotinic cholinergic receptor (α7nAChR) and SIRT1. Then in macrophages, the molecular mechanism of MG regulating the abnormal activation of macrophages in rats with early AIA through the CAP-SIRT1 pathway was studied.

Results

MG can significantly inhibit the polarization of M1 macrophages and the differentiation of Th1 in AIA rats in the acute phase of inflammation. MG can significantly inhibit the activity of AChE and increase the level of NAD+, thereby further up-regulated the expression levels of α7nAChR and SIRT1. Meanwhile, MG inhibited nuclear factor-κB (NF-κB)-mediated inflammation by activating the CAP-SIRT1 pathway in macrophages.

Conclusion

In summary, the stimulation of MG induced CAP activation, which up-regulated SIRT1 signal, and thereby inhibited M1 polarization through the NF-κB pathway, and improved the pathological immune environment of early-stage AIA rats.

1,7-Dihydroxy-3,4-Dimethoxyxanthone Inhibits Lipopolysaccharide-Induced Inflammation in RAW264.7 Macrophages by Suppressing TLR4/NF-κB Signaling Cascades

Securidaca inappendiculata Hassk. is a traditional Chinese anti-rheumatic herbal medicine native to southern China. In this study, we identified a possible TLR4 inhibitor from this plant. General effects of its xanthone-rich fraction (XRF) on inflammation in vitro were investigated by immunoblotting experiments performed on lipopolysaccharides (LPS)-treated RAW264.7 cells, and the possible ligand of TLR4 within was screened out by analyzing chemical composition differences of the XRF containing cell culture medium under different inflammatory circumstances. The interaction between ligand and TLR4 was validated by cellular thermal shift assay (CETSA) and molecular docking simulation, and TLR4/NF-κB pathway status was investigated by immunoprecipitation, ELISA, immunofluorescence, dual-luciferase reporter, and immunoblotting experiments. Treatment with XRF resulted in significant decrease in p-p65 and p-JNK, and the signal accounting for 1,7-dihydroxy-3,4-dimethoxyxanthone (XAN) at 12.5 min with mass of 289.29 was greatly decreased in XRF containing medium after LPS stimulus because of enhanced interaction with increased TLR4. CETSA and molecular docking simulation demonstrated that XAN could bind to TLR4 directly on a smooth region adjacent to its contact interface with MD-2. XAN treatment inhibited the dimerization of TLR4 and transcriptional activity of NF-κB in HEK293T cells and decreased p65 accumulation in nucleus and pro-inflammatory cytokines production in RAW264.7 cells receiving LPS treatment. Overall evidences suggest that XAN could be a selective TLR4 inhibitor with potent anti-inflammatory effects. Also, it indicated that xanthone derivatives could have promising clinical application in many immune-mediated inflammations by acting as TLR4 inhibitors.

α-Mangostin Alleviated Inflammation in Rats With Adjuvant-Induced Arthritis by Disrupting Adipocytes-Mediated Metabolism-Immune Feedback

A previously identified anti-rheumatic compound α-mangostin (MAN) possesses notable metabolism regulatory properties. In this study, we investigated the immune implication of MAN-altered fat metabolism on adjuvant-induced arthritis (AIA) in rats. Seven days after AIA induction, the rats received oral treatment of MAN at 50 mg/kg/day for 30 days. Metabolic indicators and basic clinical parameters were evaluated using samples collected on day 20 and 38 since immunization. Expression of nicotinamide phosphoribosyltransferase (NAMPT), sirtuin 1 (SIRT1), peroxisome proliferator activated receptor gamma (PPAR-γ), stearoyl-coa desaturase 1 (SCD-1), toll like receptor 4 (TLR4), prostaglandin-endoperoxide synthase 2 (COX-2), (p)-JNK, (p)-p65 and IL-1β were investigated by either RT-qPCR or immunobloting methods. In in vitro experiments, we treated (pre)-adipocytes with monocytes/macrophages and MAN, and investigated the changes of macrophages brought by pre-adipocytes co-culture. Generally, MAN restored the impaired fat anabolism in AIA rats, indicated by increased fat reservoir, leptin and adiponectin secretion, and PPAR-γ and SCD-1 expression. Meanwhile, it decreased circulating IL-1β and IL-6 levels, restored serological lipid profile changes, and relieved oxidative stresses, demonstrating potent therapeutic effects on AIA. AIA rats-derived monocytes inhibited mRNA PPAR-γ and SCD-1 expression in pre-adipocytes. Contrarily, MAN facilitated adipocyte differentiation in vitro, and increased free fatty acids production. It also significantly increased PPAR-γ and SCD-1 expression, which can be abrogated by PPAR-γ inhibitor T0070907. Similarly, lipopolysaccharide-primed macrophages inhibited PPAR-γ expression in the co-cultured pre-adipocytes, which was reversed by MAN. In the same co-culture system, lipopolysaccharide-induced inflammation was amplified by the co-existence of pre-adipocytes. More secretion of IL-1β and IL-6 and higher levels expression of COX-2, p-JNK, p-p65 and TLR4 were observed in lipopolysaccharide-treated macrophages when co-cultured by pre-adipocytes. The intensified inflammatory situation was eased by MAN. The treatment with pre-adipocytes culture medium achieved similar effects. Medium from lipopolysaccharide-treated adipocytes promoted IL-1β, IL-6 and MCP-1 production in separately cultured macrophages, and COX-2, p-JNK, p-p65 and TLR4 expression were increased at the meantime. MAN treatment on pre-adipocytes impaired these changes. It suggests that fat anabolism in AIA rats was deficient due to increased energy expenditure caused by inflammatory conditions. MAN restored fat metabolism homeostasis by up-regulating PPAR-γ, and reshaped secretion profile of adipocytes.

Activation of cholinergic anti-inflammatory pathway involved in therapeutic actions of α-mangostin on lipopolysaccharide-induced acute lung injury in rats

Introduction:

Alpha-mangostin (MAN) possesses a wide variety of pharmacological effects. In this study, we investigated its effect on cholinergic anti-inflammatory pathway (CAP), and tested if CAP regulation was involved in the therapeutic action on acute lung injury (ALI).

Methods:

Male Sprague Dawley rats were pre-treated with MAN (40 mg/kg) for 3 days and ALI was induced with an intraperitoneal injection of lipopolysaccharide (LPS). Certain rats received monolateral vagotomy or sham surgery. The effects on inflammatory reactions and relevant pathways in ALI rats or LPS pre-treated RAW 264.7 cells were investigated by histological, immunohistochemical, immunoblotting, RT-qPCR, and immunofluorescence assays, while levels of proinflammatory cytokines, acetylcholine (Ach) and the enzymatic activity of acetylcholinesterase (AchE) were determined by corresponding quantitative kits.

Results:

Oral administration of MAN reduced the severity of ALI, while vagotomy surgery antagonized this effect. MAN restored the decline in α7 nicotinic acetylcholine receptor (α7nAchR) in the lungs of ALI rats, and promoted the expression of α7nAchR and choline acetyltransferase (CHAT) in RAW 264.7 cells. Although AchE expression was barely affected by MAN at 5 μg/ml, its catalytic activity was reduced by almost 95%. Extracellular rather than intracellular Ach was notably raised shortly after MAN treatment. Furthermore, MAN at 5 μg/ml effectively inhibited LPS-induced increase in phosphorylation and nucleus translocation of p65 subunit, and secretion of TNF-α and IL-1β, which was then offset by methyllycaconitine citrate hydrate.

Conclusion:

MAN activated CAP by increasing peripheral Ach and up-regulating α7nAchR expression, which eventually led to NF-κB inhibition and remission of acute inflammations.

Polyphenols from Securidaca inappendiculata alleviated acute lung injury in rats by inhibiting oxidative stress sensitive pathways

Objective

Securidaca inappendiculata is a medicinal plant frequently used in the treatment of inflammatory diseases in south China. In this study, we aimed to explore its bioactive constituent which contributes to the anti-inflammatory activity.

Methods

Polyphenol-enriched and polyphenol-deprived fractions (PRF and PDF, respectively) were separated from the ethanolic extract by HPD300 macroporous resin-based method, and their anti-inflammatory activities were investigated on a lipopolysaccharide (LPS)-induced acute lung injury (ALI) model in rats. The possible mechanism of action in alleviating acute inflammation was studied using RAW264.7 cells.

Results

Both Folin-Ciocalteu and ¹H nuclear magnetic resonance (NMR) analyses showed that polyphenolic content in PRF was approximately 10 times higher than that of PDF, and this observation reflected in their antioxidative capacities. PRF but not PDF significantly decreased the level of malondialdehyde, suppressed the expression of nicotinamide phosphoribosyltransferase (NAMPT) protein, and improved the severity of ALI in rats. PRF at 10 μg/mL effectively downregulated the expression of proteins NAMPT, HMGB1, TLR4, and p-p65, and scavenged the intracellular reactive oxygen species (ROS) in LPS-primed RAW264.7 cells. N-acetyl-L-cysteine exhibited similar inhibitory effects on ROS production and NAMPT-mediated TLR4/NF-κB activation in vitro, whereas nicotinamide mononucleotide antagonized all the changes induced by PRF during cotreatments.

Conclusion

As an antioxidant, PRF exhibited potent anti-inflammatory activity under both in vivo and in vitro conditions by downregulating NAMPT and TLR4/NF-κB. Accordingly, polyphenols were identified as important bioactive constituents in S. inappendiculata targeting oxidative stress-sensitive pro-inflammatory pathways.

Nicotinamide mononucleotide-elicited NAMPT signaling activation aggravated adjuvant-induced arthritis in rats by affecting peripheral immune cells differentiation

Supplement of nicotinamide mononucleotide (NMN), the direct precursor of nicotinamide adenine dinucleotide (NAD⁺) has gained prominence due to the significant anti-aging potentials of nicotinamide phosphoribosyltransferas (NAMPT)/NAD⁺ signaling. Because over-expression of NAMPT is deeply implicated in inflammatory arthritis, we investigated the effects of NMN supplement on rats with adjuvant-induced arthritis (AIA). Tested rats were given oral treatment of NMN at 200 mg/kg/day for 25 days. Arthritis score and body weight were periodically recorded. Clinical outcomes were evaluated based on arthritic manifestations, ELISA analysis and histological examination. T cells subsets were analyzed by flow cytometry. Expressions of protein and mRNA were assessed by immunoblotting and PCR methods, respectively. Levels of CD172a, CD43, and NAMPT in peripheral blood mononuclear cells (PBMCs) were investigated by immunofluorescence approach. Obtained results were further validated by experiments in vitro. Generally, NMN exacerbated AIA severity in rats. It deteriorated MMP3-controlled tissues damages, and altered immune profile by increasing Th17/Treg cells ratio. The up-regulation of NAMPT in PBMCs from NMN-treated rats was confirmed by both immunofluorescence and PCR experiments, which was synchronized with significant increase in iNOS, MCP-1, IL-1β expression. NMN-primed AIA PBMCs were potent in up-regulating MCP-1, IL-1β, MMP3 and p-JNK expression in synovioblast. NMN stimulus barely affected Th17 cells count in in vitro cultured splenocytes, but it greatly potentiated the capability of AIA monocytes in inducing IL-17α secretion and Th17 cells differentiation in the co-cultured splenocytes. It suggested that long-term NMN supplement could exacerbate inflammatory arthritis by reshaping the immune milieu through the up-regulation of NAMPT.

MiR-96-5p alleviates inflammatory responses by targeting NAMPT and regulating the NF-κB pathway in neonatal sepsis

Neonatal septicemia is a serious infectious disease in the neonatal period. MicroRNAs (miRNAs) have been reported to participate in the inflammatory responses in neonatal sepsis. The aim of the present study was to explore the effects and molecular mechanism of miR-96-5p on regulating the inflammatory responses in neonatal sepsis. MiR-96-5p was low expressed while nicotinamide phosphoribosyltransferase (NAMPT) was high expressed in the serum of neonatal septicemia patients. The expression of miR-96-5p was decreased in LPS-induced inflammatory responses. Besides, miR-95-5p relieved LPS-induced inflammatory responses in RAW264.7 cells. NAMPT was demonstrated as a potential target of miR-96-5p, and knockdown of NAMPT reduced inflammatory in RAW264.7 cells stimulated with LPS. Moreover, overexpression of NAMPT reversed the effects of miR-96-5p on LPS-induced inflammatory responses. In addition, miR-96-5p inhibited nuclear factor (NF)-κB signaling pathway in RAW264.7 cells stimulated with LPS. MiR-96-5p alleviated inflammatory responses via targeting NAMPT and inhibiting NF-κB pathway in neonatal sepsis.

Activation of Cholinergic Anti-Inflammatory Pathway in Peripheral Immune Cells Involved in Therapeutic Actions of α-Mangostin on Collagen-Induced Arthritis in Rats

Background

Studies have shown that α-mangostin (MG) could exert anti-rheumatic effects in vivo by restoring immunity homeostasis, and have indicated that activation of the choline anti-inflammatory pathway (CAP) may contribute to this immunomodulatory property. The current study was designed to further investigate the effects of MG on the CAP in peripheral immune cells and clarify its relevance to the potential anti-rheumatic actions.

Methods

The catalytic activity of acetylcholinesterase (AChE) and expression of α7-nicotinic cholinergic receptor (α7nAChR) in peripheral blood mononuclear cells (PBMCs) from rats with collagen-induced arthritis (CIA) or human volunteers were evaluated after MG treatment. Consequent influences on the immune environment were assessed by flow cytometry and ELISA analyses. Indirect effects on joints resulting from these immune changes were studied in a co-culture system comprised of fibroblast-like synoviocytes (FLSs) and PBMCs.

Results

MG promoted α7nAChR expression in PBMCs both in vivo and in vitro, and inhibited the enzymatic activity of AChE simultaneously. Activation of the CAP was accompanied by a significant decrease in Th17 cells (CD4⁺IL-17A⁺), while no obvious changes concerning the distribution of other T-cell subsets were noticed upon MG treatment. Meanwhile, MG decreased the secretion of TNF-α and IL-1β under inflammatory conditions. PBMCs from MG-treated CIA rats lost the potential to stimulate NF-κB activation and pro-inflammatory cytokine production of FLSs in the co-culture system.

Conclusion

Overall, the evidence suggested that MG can improve the peripheral immune milieu in CIA rats by suppressing Th17-cell differentiation through CAP activation, and achieve remission of inflammation mediated by FLSs.

Alpha-mangostin reduces mechanical stiffness of various cells

Alpha-mangostin (α-mangostin) has been identified as a naturally occurring compound with potential anticancer properties. It can induce apoptosis and inhibit the growth and metastasis of cancer cells. Moreover, α-mangostin reduces the mechanical stiffness of lung cancer cells. The objective of this study was to determine the effect of α-mangostin on the mechanical stiffness of various cells, as well as cell viability. The following cell types were examined: human fibroblast TIG-1 cells, human cancerous HeLa cells, human embryonic kidney HEK293 cells, mouse macrophage RAW 264.7 cells, and human myeloblasts KG-1 cells. Cells were treated with α-mangostin, and then examined for cell viability, actin cytoskeletal structures, and surface mechanical stiffness using atomic force microscopy. α-Mangostin demonstrated cytotoxicity against TIG-1, HeLa, HEK293, and KG-1 cells, but not against RAW 264.7 cells. The cytotoxic effect of α-mangostin varies according to cell type. On the other hand, α-mangostin reduced the mechanical stiffness of all cell types, including RAW 264.7 cells. Upon treatment with α-mangostin, F-actin was slightly reduced but the actin cytoskeletal structures were little altered in these cells. Thus, reducing mechanical stiffness of animal cells is an inherent effect of α-mangostin. Our results show that α-mangostin is a naturally occurring compound with potential to change the actin cytoskeletal micro-structures and reduce the surface stiffness of various cells.

α-Mangostin reduced the viability of A594 cells in vitro by provoking ROS production through downregulation of NAMPT/NAD

α-Mangostin (MAN) is a bioactive compound isolated from the inedible pericarp of a tropical fruit mangosteen (Garcinia mangostana Linn). It exhibits notable therapeutic potentials on lung cancers, but the underlying mechanisms are still largely unknown. This study was designed to further explore the mechanisms involved in cytotoxicity of MAN on A549 cells. Apoptosis and cell cycle distribution were analyzed by flow cytometry methods. The fluorescent probes DCFH-DA and JC-1 were used to assess the intracellular reactive oxidative species (ROS) and mitochondrial membrane potential statuses, respectively. The regulation of MAN on relevant pathways was investigated by immunoblotting assays. The results obtained indicated that MAN caused significant apoptosis and cell cycle arrest in A549 cells, which eventually resulted in inhibition on cell proliferation in vitro. All these phenomena were synchronized with escalated oxidative stress and downregulation of nicotinamide phosphoribosyltransferase/nicotinamide adenine dinucleotide (NAMPT/NAD). Supplementation with nicotinamide mononucleotide (NMN) and N-acetylcysteine (NAC) efficiently eased MAN-induced ROS accumulation, and potently antagonized MAN-elicited apoptosis and cell cycle arrest. The pro-apoptotic effect of MAN was further confirmed by increased expressions of cleaved caspase 3, 6, 7, and 9, and its effect on cell cycle progression was validated by the altered expressions of p-p38, p-p53, CDK4, and cyclin D1. The immunoblotting assays also demonstrated that NAC/NMN effectively restored these molecular changes elicited by MAN treatment. Collectively, this study revealed a unique anti-tumor mechanism of MAN by provoking ROS production through downregulation of NAMPT/NAD signaling and further validated MAN as a potential therapeutic reagent for lung cancer treatment.

Crude α-Mangostin Suppresses the Development of Atherosclerotic Lesions in Apoe-Deficient Mice by a Possible M2 Macrophage-Mediated Mechanism

Lifestyle choices play a significant role in the etiology of atherosclerosis. Male Apoe^−/− mice that develop spontaneous atherosclerotic lesions were fed 0%, 0.3%, and 0.4% mangosteen extracts, composed largely of α-mangostin (MG), for 17 weeks. Body weight gains were significantly decreased in both MG-treated groups compared to the control, but the general condition remained good throughout the study. The levels of total cholesterol (decreased very-low-density lipoprotein in lipoprotein profile) and triglycerides decreased significantly in the MG-treated mice in conjunction with decreased hepatic HMG-CoA synthase and Fatty acid transporter. Additionally, increased serum lipoprotein lipase activity and histopathology further showed a significant reduction in atherosclerotic lesions at both levels of MG exposure. Real-time PCR analysis for macrophage indicators showed a significant elevation in the levels of Cd163, an M2 macrophage marker, in the lesions of mice receiving 0.4% MG. However, the levels of Nos2, associated with M1 macrophages, showed no change. In addition, quantitative immunohistochemical analysis of macrophage subtypes showed a tendency for increased M2 populations (CD68⁺/CD163⁺) in the lesions of mice given 0.4% MG. In further analysis of the cytokine-polarizing macrophage subtypes, the levels of Interleukin13 (Il13), associated with M2 polarization, were significantly elevated in lesions exposed to 0.4% MG. Thus, MG could suppress the development of atherosclerosis in Apoe^−/− mice, possibly through an M2 macrophage-mediated mechanism.