Inhibition Of Macrophage Activation Research Articles

Baseline data collections of lipopolysaccharide content in 414 herbal extracts and its role in innate immune activation

Some herbal extracts contain relatively high amounts of lipopolysaccharide (LPS). Because orally administered LPS activates innate immunity without inducing inflammation, it plays a role as an active ingredient in herbal extracts. However, the LPS content in herbal extracts remains extensively unevaluated. This study aimed to create a database of LPS content in herbal extracts; therefore, the LPS content of 414 herbal extracts was measured and the macrophage activation potential was evaluated. The LPS content of these hot water extracts was determined using the kinetic–turbidimetric method. The LPS concentration ranged from a few ng/g to hundreds of μg/g (Standard Escherichia coli LPS equivalent). Twelve samples had a high-LPS-content of > 100 μg/g, including seven samples from roots and three samples from leaves of the herbal extracts. These samples showed high phagocytosis and NO production capacity, and further investigation using polymyxin B, an LPS inhibitor, significantly inhibited macrophage activation. This study suggests that some herbal extracts contain sufficient LPS concentration to activate innate immunity. Therefore, a new approach to evaluate the efficacy of herbal extracts based on their LPS content was proposed. A database listing the LPS content of different herbal extracts is essential for this approach.

ANGPTL3 accelerates atherosclerotic progression via direct regulation of M1 macrophage activation in plaque

IntroductionThe N-terminal domain of angiopoietin-like protein 3 (ANGPTL3) inhibits lipoprotein lipase activity. Its C-terminal fibrinogen-like (FBN) domain is a ligand of macrophage integrin αvβ3. ObjectivesANGPTL3 might home to plaque where it directly regulates macrophage function via integrin αvβ3 for atherosclerosis progression. MethodsLdlr-/- mice on a high-fat diet and ApoE-/- mice on a chow diet were received adeno-associated virus (AAV)-mediated Angptl3 gene transfer and followed up for 12 weeks. ApoE-/- mice were injected AAV containing FLAG-tagged Angptl3 cDNA for tracing. Atherosclerotic features were compared between Angptl3-/-ApoE-/- mice and ApoE-/- littermates. THP-1 cells were exposed to 0 or 50 μg/ml ANGPTL3 FBN domain for 24 h to evaluate Toll-like receptor (TLR)4 expression using western blot analysis and circulating cytokine and chemokine profiles by the MILLIPLEX MAP assay. Phospho-proteomic profile was established in ANGPTL3-treated macrophages. Integrin β3 deficient THP-1 cells were obtained by sgRNAs targeting RGD sequence using Lentivirus-Cas9 system. ResultsAngptl3 overexpression increased atherosclerotic progression and CD68+ macrophages in plaque (p < 0.05 for all). By immunostaining, FLAG+ cells were identified in plaque of gene transferred ApoE-/- mice. Fluorescent immunostaining detected co-localisation of Angptl3 and CD68 in plaque macrophages. Phospho-proteomic analysis revealed that Angptl3 induced phosphorylation of proteins that were involved in the IL-17 signalling pathway in THP-1 cells. In vitro, ANGPTL3 treatment increased the production of interleukin (IL)-1β and tumour necrosis factor-α in THP-1 cells (p < 0.05 for both). Exposure of ANGPTL3 to THP-1 cells induced Akt phosphorylation which was weakened in integrin β3 deficient ones. ANGPTL3 elevated TLR4 expression via Akt phosphorylation. In response to lipopolysaccharide, nuclear factor-κB activity was 2.2-fold higher in THP-1 cells pre-treated with ANGPTL3 than in untreated cells (p < 0.05). ConclusionsTargeting ANGPTL3 could yield a dual benefit of lowering lipid levels in the blood and suppressing macrophage activation in plaque.

Bu-Shen-Ning-Xin decoction inhibits macrophage activation to ameliorate premature ovarian insufficiency-related osteoimmune disorder via FSH/FSHR pathway.

Limited studies are associated with premature ovarian insufficiency (POI)-related osteoimmune disorder currently. Bu-Shen-Ning-Xin decoction (BSNXD) displayed a favorable role in treating postmenopausal osteoporosis. However, its impact on the POI-related osteoimmune disorder remains unclear. The study primarily utilized animal experiments and network pharmacology to investigate the effects and underlying mechanisms of BSNXD on the POI-related osteoimmune disorder. First, a 4-vinylcyclohexene dioxide (VCD)-induced POI murine model was conducted to explore the therapeutical action of BSNXD. Second, we analyzed the active compounds of BSNXD and predicted their potential mechanisms for POI-related osteoimmune disorder via network pharmacology, further confirmed by molecular biology experiments. The results demonstrated that VCD exposure led to elevated follicle-stimulating hormone (FSH) levels, a 50% reduction in the primordial follicles, bone microstructure changes, and macrophage activation, indicating an osteoimmune disorder. BSNXD inhibited macrophage activation and osteoclast differentiation but did not affect serum FSH and estradiol levels in the VCD-induced POI model. Network pharmacology predicted the potential mechanisms of BSNXD against the POI-related osteoimmune disorder involving tumor necrosis factor α and MAPK signaling pathways, highlighting BSNXD regulated inflammation, hormone, and osteoclast differentiation. Further experiments identified BSNXD treatment suppressed macrophage activation via downregulating FSH receptor (FSHR) expression and inhibiting the phosphorylation of ERK and CCAAT enhancer binding proteins β. In conclusion, BSNXD regulated POI-related osteoimmune disorder by suppressing the FSH/FSHR pathway to reduce macrophage activation and further inhibiting osteoclastogenesis.

Alpha-lipoic acid ameliorates influenza A virus caused acute pneumonia though enhancement of anti-viral T cell immunity and suppression of macrophage activation by inhibiting ERK1/2 signaling pathway

The first outbreak of influenza A virus (IAV), which has been circulating for many decades, has resulted in serious morbidity and mortality. The IAV epidemic has caused serious damage to human life and the economy. Following an IAV infection, lymphatic cells immediately enter the lungs to clear the virus and eliminate damaged cells to maintain normal physiological mechanisms. In this study, we used alpha-lipoic acid (ALA), which has versatile antioxidant functions, as a target to treat and evaluate host antiviral effects and immune mechanisms. We observed that pre-treatment with ALA improved the survival rate and pathological state in a mouse model. A reduction in the inflammatory cytokine tumor necrosis factor-alpha was observed following in vivo experiments. It also increased the release of antiviral cytokines into the lungs by T lymphocytes. ALA pre-treatment effectively prevented acute pneumonia by modulating immune composition and contributing to virus clearance.

Nanomedicine‐encouraged cellular autophagy promoters favor liver fibrosis progression reversal

AbstractLiver fibrosis is a major risk factor for hepatocellular carcinoma origin, and its progression not only correlates with oxidative stress and inflammation, but also is encouraged by autophagy hold‐up. Therefore, new solutions to effectively attenuate oxidative stress and inflammation and coincidently favor autophagy are highly demanded to reverse liver fibrosis, and even hamper its escalation into hepatocellular carcinoma. Herein, the porous manganese‐substituted Prussian blue (PMPB) analogs are harnessed to activate autophagy, scavenge reactive oxygen species (ROS), and suppress inflammation for liver fibrosis therapy. PMPB can effectively inhibit macrophage activation, facilitate macrophage autophagy, eradicate ROS, and blockade cellular cross‐talk, thus impeding further inflammation progression. Moreover, the favorable spontaneous capture of PMPB by Kupffer cells allows more PMPB accumulation in liver to significantly attenuate liver injury and collagen deposition, thereby inhibiting the progression of liver fibrosis. PMPB‐based nanomedicine shows great potentials in promoting autophagy activation, eliminating ROS, inhibiting inflammation, and protecting hepatocytes from oxidative stress‐arised damages, which eventually attenuate the extent of liver fibrosis, holding great promise in clinical translation for treating liver fibrosis.

Disulfiram treatment suppresses antibody-producing reactions by inhibiting macrophage activation and B cell pyrimidine metabolism

Disulfiram treatment suppresses antibody-producing reactions by inhibiting macrophage activation and B cell pyrimidine metabolism

TSG6-Exo@CS/GP Attenuates Endometrium Fibrosis by Inhibiting Macrophage Activation in a Murine IUA Model.

Intrauterine adhesion (IUA) is characterized by the formation of fibrous scar tissue within the uterine cavity, which significantly impacts female reproductive health and even leads to infertility. Unfortunately, severe cases of IUA currently lack effective treatments. This study presents a novel approach that utilizes tumor necrosis factor-(TNF) stimulated gene 6 (TSG6)-modified exosomes (Exos) in conjunction with an injectable thermosensitive hydrogel (CS/GP) to mitigate the occurrence of IUA by reducing endometrium fibrosis in a mouse IUA model. This study demonstrate that TSG6-modified Exos effectively inhibits the activation of inflammatory M1-like macrophages during the initial stages of inflammation and maintains the balance of macrophage phenotypes (M1/M2) during the repair phase. Moreover, TSG6 inhibits the interaction between macrophages and endometrial stromal fibroblasts, thereby preventing the activation of stromal fibroblasts into myofibroblasts. Furthermore, this research indicates that CS/GP facilitates the sustained release of TSG6-modified Exos, leading to a significant reduction in both the manifestations of IUA and the extent of endometrium fibrosis. Collectively, through the successful construction of CS/GP loaded with TSG6-modified Exos, a reduction in the occurrence and progression of IUA is achieved by mitigating endometrium fibrosis. Consequently, this approach holds promise for the treatment of IUA.

L-AP Alleviates Liver Injury in Septic Mice by Inhibiting Macrophage Activation via Suppressing NF-κB and NLRP3 Inflammasome/Caspase-1 Signal Pathways.

Liver injury and progressive liver failure are severe life-threatening complications in sepsis, further worsening the disease and leading to death. Macrophages and their mediated inflammatory cytokine storm are critical regulators in the occurrence and progression of liver injury in sepsis, for which effective treatments are still lacking. l-Ascorbic acid 6-palmitate (L-AP), a food additive, can inhibit neuroinflammation by modulating the phenotype of the microglia, but its pharmacological action in septic liver damage has not been fully explored. We aimed to investigate L-AP's antisepticemia action and the possible pharmacological mechanisms in attenuating septic liver damage by modulating macrophage function. We observed that L-AP treatment significantly increased survival in cecal ligation and puncture-induced WT mice and attenuated hepatic inflammatory injury, including the histopathology of the liver tissues, hepatocyte apoptosis, and the liver enzyme levels in plasma, which were comparable to NLRP3-deficiency in septic mice. L-AP supplementation significantly attenuated the excessive inflammatory response in hepatic tissues of septic mice in vivo and in cultured macrophages challenged by both LPS and ATP in vitro, by reducing the levels of NLRP3, pro-IL-1β, and pro-IL-18 mRNA expression, as well as the levels of proteins for p-I-κB-α, p-NF-κB-p65, NLRP3, cleaved-caspase-1, IL-1β, and IL-18. Additionally, it impaired the inflammasome ASC spot activation and reduced the inflammatory factor contents, including IL-1β and IL-18 in plasma/cultured superannuants. It also prevented the infiltration/migration of macrophages and their M1-like inflammatory polarization while improving their M2-like polarization. Overall, our findings revealed that L-AP protected against sepsis by reducing macrophage activation and inflammatory cytokine production by suppressing their activation in NF-κB and NLRP3 inflammasome signal pathways in septic liver.

Targeting STAT6-mediated synovial macrophage activation improves pain in experimental knee osteoarthritis

BackgroundPain from osteoarthritis (OA) is one of the top causes of disability worldwide, but effective treatment is lacking. Nociceptive factors are released by activated synovial macrophages in OA, but depletion of synovial macrophages paradoxically worsens inflammation and tissue damage in previous studies. Rather than depleting macrophages, we hypothesized that inhibiting macrophage activation may improve pain without increasing tissue damage. We aimed to identify key mechanisms mediating synovial macrophage activation and test the role of STAT signaling in macrophages on pain outcomes in experimental knee OA.MethodsWe induced experimental knee OA in rats via knee destabilization surgery, and performed RNA sequencing analysis on sorted synovial tissue macrophages to identify macrophage activation mechanisms. Liposomes laden with STAT1 or STAT6 inhibitors, vehicle (control), or clodronate (depletion control) were delivered selectively to synovial macrophages via serial intra-articular injections up to 12 weeks after OA induction. Treatment effects on knee and hindpaw mechanical pain sensitivity were measured during OA development, along with synovitis, cartilage damage, and synovial macrophage infiltration using histopathology and immunofluorescence. Lastly, crosstalk between drug-treated synovial tissue and articular chondrocytes was assessed in co-culture.ResultsThe majority of pathways identified by transcriptomic analyses in OA synovial macrophages involve STAT signaling. As expected, macrophage depletion reduced pain, but increased synovial tissue fibrosis and vascularization. In contrast, STAT6 inhibition in macrophages led to marked, sustained improvements in mechanical pain sensitivity and synovial inflammation without worsening synovial or cartilage pathology. During co-culture, STAT6 inhibitor-treated synovial tissue had minimal effects on healthy chondrocyte gene expression, whereas STAT1 inhibitor-treated synovium induced changes in numerous cartilage turnover-related genes.ConclusionThese results suggest that STAT signaling is a major mediator of synovial macrophage activation in experimental knee OA. STAT6 may be a key mechanism mediating the release of nociceptive factors from macrophages and the development of mechanical pain sensitivity. Whereas therapeutic depletion of macrophages paradoxically increases inflammation and fibrosis, blocking STAT6-mediated synovial macrophage activation may be a novel strategy for OA-pain management without accelerating tissue damage.

Cayratia albifolia C.L.Li exerts anti-rheumatoid arthritis effect by inhibiting macrophage activation and neutrophil extracellular traps (NETs)

BackgroundCayratia albifolia C.L.Li (CAC), commonly known as “Jiao-Mei-Gu” in China, has been extensively utilized by the Dong minority for several millennia to effectively alleviate symptoms associated with autoimmune diseases. CAC extract is believed to possess significant anti-inflammatory properties within the context of Dong medicine. However, an in-depth understanding of the specific pharmaceutical effects and underlying mechanisms through which CAC extract acts against rheumatoid arthritis (RA) has yet to be established.MethodsTwenty-four Sprague–Dawley rats were divided into four groups, with six rats in each group. To induce the collagen-induced arthritis (CIA) model, the rats underwent a process of double immunization with collagen and adjuvant. CAC extract (100 mg/kg) was orally administered to rats. The anti-RA effects were evaluated in CIA rats by arthritis score, hind paw volume and histopathology analysis. Pull-down assay was conducted to identify the potential targets of CAC extract from RAW264.7 macrophage lysates. Moreover, mechanism studies of CAC extract were performed by immunofluorescence assays, real-time PCR and Western blot.ResultsCAC extract was found to obviously down-regulate hind paw volume of CIA rats, with diminished inflammation response and damage. 177 targets were identified from CAC extract by MS-based pull-down assay. Bioinformatics analysis found that these targets were mainly enriched in macrophage activation and neutrophils extracellular traps (NETs). Additionally, we reported that CAC extract owned significant anti-inflammatory activity by regulating PI3K-Akt-mTOR signal pathway, and inhibited NETosis in response to PMA.ConclusionsWe clarified that CAC extract significantly attenuated RA by inactivating macrophage and reducing NETosis via a multi-targets regulation.Graphical

Treatment with lysophosphatidic acid improves glomerulonephritis through the suppression of macrophage activation in a murine model of systemic lupus erythematosus.

Several therapeutic agents have been developed and used for the clinical treatment of systemic lupus erythematosus (SLE). In cases where SLE is accompanied by severe organ failures, such as neuropsychiatric lupus erythematosus (NPSLE) and acute onset of lupus nephritis, the use of potent immunosuppressive drugs, such as cyclophosphamide, is necessary. However, potent immunosuppressive drugs are known to increase infection risks. Thus, the development of therapeutic agents with novel mechanisms is urgently required. Previously, we reported that treatment with lysophosphatidic acid (LPA) prevents depression-like behaviours by suppressing microglial activation in MRL/lpr mice. In this study, we examined whether the treatment with LPA improves glomerulonephritis by affecting systemic immunity in MRL/lpr mice. Eighteen-week-old MRL/lpr mice were treated with a vehicle or LPA for 3 weeks. After treatment, the glomerular inflammation and damage parameters were compared between the 2 groups. Moreover, we examined the effects of LPA on immune cells by flow cytometry using isolated splenocytes. LPA treatment in MRL/lpr mice significantly reduced the daily urinary albumin content and suppressed the CD68-positive cells and Periodic acid-Schiff (PAS)-positive areas in the glomeruli. The treatment also suppressed plasma anti-dsDNA antibodies and inflammatory cytokines in MRL/lpr mice. Although LPA did not significantly affect the total number of splenocytes, the treatment significantly reduced CD11b+Ly6G-Ly6C- cells (mature macrophages), as well as CD11b+Ly6G-Ly6C-CD68+ cells (activated mature macrophages). These results suggest that LPA may improve glomerulonephritis by suppressing macrophage activation in MRL/lpr mice.

Integrated network pharmacology and experimental validation-based approach to reveal the underlying mechanisms and key material basis of Jinhua Qinggan granules against acute lung injury

Ethnopharmacological relevanceJinhua Qinggan granules (JHQG), the traditional Chinese formula come into the market in 2016, has been proved clinically effective against coronavirus disease. Acute lung injury (ALI) is a major complication of respiratory infection such as coronavirus and influenza virus, with a high clinical fatality rate. Macrophage activation-induced inflammatory response plays a crucial role in the pathogenesis of ALI. However, the participation of inflammatory response in the efficacy of JHQG and its material basis against ALI is still unknown. Aim of the studyThe research aims to investigate the inflammatory response-involved efficacy of JHQG on ALI, explore the “ingredient-target-pathway” mechanisms, and searching for key material basis of JHQG by integrated network pharmacology and experimental validation-based approach. Materials and methodsLipopolysaccharide (LPS)-induced ALI mice was established to assess the protective impact of JHQG. Network pharmacology was utilized to identify potential targets of JHQG and investigate its action mechanisms related to inflammatory response in treating ALI. The therapeutic effect and mechanism of the primary active ingredient in JHQG was verified through high performance liquid chromatography (HPLC) and a combination of wet experiments. ResultsJHQG remarkably alleviated lung damage in mice model via suppressing macrophage activation, and inhibiting pro-inflammatory mediator level, p-ERK and p-STAT3 expression, TLR4/NF-κB activation. Network pharmacology combined with HPLC found luteolin is the main effective component of JHQG, and it could interact with TLR4/MD2 complex, further exerting the anti-inflammatory property and the protective role against ALI. ConclusionsIn summary, our finding clarified the underlying mechanisms and material basis of JHQG therapy for ALI by integrated network pharmacology and experimental validation-based strategy.

ZNFX1 promotes AMPK-mediated autophagy against Mycobacterium tuberculosis by stabilizing Prkaa2 mRNA.

Tuberculosis has the highest mortality rate worldwide for a chronic infectious disease caused by a single pathogen. RNA-binding proteins (RBPs) are involved in autophagy - a key defense mechanism against Mycobacterium tuberculosis (M. tuberculosis) infection - by modulating RNA stability and forming intricate regulatory networks. However, the functions of host RBPs during M. tuberculosis infection remain relatively unexplored. Zinc finger NFX1-type containing 1 (ZNFX1), a conserved RBP critically involved in immune deficiency diseases and mycobacterial infections, is significantly upregulated in M. tuberculosis-infected macrophages. Here, we aimed to explore the immunoregulatory functions of ZNFX1 during M. tuberculosis infection. We observed that Znfx1 knockout markedly compromised the multifaceted immune responses mediated by macrophages. This compromise resulted in reduced phagocytosis, suppressed macrophage activation, increased M. tuberculosis burden, progressive lung tissue injury, and chronic inflammation in M. tuberculosis-infected mice. Mechanistic investigations revealed that the absence of ZNFX1 inhibited autophagy, consequently mediating immune suppression. ZNFX1 critically maintained AMPK-regulated autophagic flux by stabilizing protein kinase AMP-activated catalytic subunit alpha 2 mRNA, which encodes a key catalytic α subunit of AMPK, through its zinc finger region. This process contributed to M. tuberculosis growth suppression. These findings reveal a function of ZNFX1 in establishing anti-M. tuberculosis immune responses, enhancing our understanding of the roles of RBPs in tuberculosis immunity and providing a promising approach to bolster antituberculosis immunotherapy.

Novel Flavanone Naringenin Derivative with Anti-Inflammatory Activity

Naringenin is a flavonoid with several biological activities already reported but with few biological applications in the pharmaceutical field. In this work, a new flavanone, called carboxymidamide (DCHA), synthesized through the condensation reaction between naringenin and aminoguanidine is structurally confirmed through spectroscopic analysis of nuclear magnetic resonance, mass spectrometry and Fourier transform infrared. DCHA was not toxic to human fibroblasts and inhibited macrophage activation in vitro. In vivo, it suppressed leukocyte migration in lipopolysaccharide (LPS)-induced peritonitis and reduced zymosan-induced paw edema. Molecular docking simulations of DCHA in the active site of the enzymes inducible nitric oxide synthase, cyclooxygenase-2 and phosphodiesterase type 4 indicate that the anti-inflammatory activity of this new flavanone can be explained by the inhibition of these target enzymes. This is the first work to present the synthesis of a flavonoid derivative with aminoguanidine that showed a high anti-inflammatory potential.

Itaconate suppresses atherosclerosis by activating a Nrf2-dependent antiinflammatory response in macrophages in mice.

Itaconate has emerged as a critical immunoregulatory metabolite. Here, we examined the therapeutic potential of itaconate in atherosclerosis. We found that both itaconate and the enzyme that synthesizes it, aconitate decarboxylase 1 (Acod1, also known as immune-responsive gene 1 [IRG1]), are upregulated during atherogenesis in mice. Deletion of Acod1 in myeloid cells exacerbated inflammation and atherosclerosis in vivo and resulted in an elevated frequency of a specific subset of M1-polarized proinflammatory macrophages in the atherosclerotic aorta. Importantly, Acod1 levels were inversely correlated with clinical occlusion in atherosclerotic human aorta specimens. Treating mice with the itaconate derivative 4-octyl itaconate attenuated inflammation and atherosclerosis induced by high cholesterol. Mechanistically, we found that the antioxidant transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), was required for itaconate to suppress macrophage activation induced by oxidized lipids in vitro and to decrease atherosclerotic lesion areas in vivo. Overall, our work shows that itaconate suppresses atherogenesis by inducing Nrf2-dependent inhibition of proinflammatory responses in macrophages. Activation of the itaconate pathway may represent an important approach to treat atherosclerosis.

Bacteroides thetaiotaomicron and its inactivated bacteria ameliorate colitis by inhibiting macrophage activation

BackgroundStudies have demonstrated that Bacteroides thetaiotaomicron (BT) has protective effect against colon inflammation in murine models. Macrophages play an important role in gut immunity. However, the specific mechanisms of BT on macrophage are still unelucidated. Thus, our study investigates the anti-inflammatory effect of BT and its heat-treated inactivated bacteria on experimental colitis and macrophages. MethodsA dextran sulfate sodium (DSS)-induced acute colitis model with male C57BL/6 mice, BT (ATCC29148) strain, THP1 cell lines were used in this study. Live and heat-treated inactivated BT (IBT) solution (1 × 10^9cfu/ml) were intragastrically gavaged daily for 14 days. Colonic inflammation was determined by the disease activity index (DAI) score, colon length, histological score, and inflammatory factors. THP1 cells were induced towards M1, then treated with different concentrations of inactivated BT solution and p38 inhibitor. Western blotting, immunohistochemistry, immunofluorescence and qRT-PCR were performed to assess the levels of inflammatory cytokines and molecules of MAPK pathway including IL-6, TNF-α, IL-1β, IL-22, p38 and phosphor-p38 expressions. Moreover, 16S rRNA sequencing of colitis murine fecal samples was applied to investigate the influence of supplementation of BT to the gut microbiota homeostasis. ResultsBoth live and heat-treated inactivated BT decreased the DAI and histological scores as well as levels of inflammatory factors, particularly IL-6 while increasing IL-22 of DSS-induced colitis murine models. The cell experiments showed that inactivated BT downregulates IL-6 expression in THP1 via inhibiting p38 phosphorylation and affecting M1 polarization. Moreover, the 16S rRNA sequencing results showed that BT and IBT gavage could increase beta-diversity of gut flora in DSS-induced colitis mice. Furthermore, the significance test for differences between the groups showed that BT could increase Faecalebaculum, Lactobacillus and Bacteroides, while decreasing Akkermansia. ConclusionIn summary, our findings imply that BT and its heat-treated inactivated bacteria exert a protective effect by suppressing macrophage-induced IL-6 through the inhibition of p38 MAPK pathway and ameliorating intestinal gut dysbiosis in experimental colitis.

Design and synthesis of novel hederagonic acid analogs as potent anti-inflammatory compounds capable of protecting against LPS-induced acute lung injury

Acute lung injury (ALI) presents a significant clinical challenge due to its high mortality rates and the lack of effective treatment strategies. The most effective approaches to treating ALI include disrupting inflammatory cascades and associated inflammatory damage within the lung. Hederagenin was utilized as a core skeleton to design and synthesize 33 hederagonic acid derivatives. Among these derivatives, compound 29 demonstrated potent anti-inflammatory activity without inducing cytotoxicity, inhibiting nitric oxide (NO) release by 78–86 %. Detailed structure-activity relationship studies and the reverse virtual screening of ALI-related targets revealed that compound 29 exhibits a high affinity for the STING protein. Mechanistic studies revealed that compound 29 suppresses macrophage activation, inhibits the nuclear translocation of IRF3 and p65, and disrupts the STING/IRF3/NF-κB signaling pathway, thereby attenuating the inflammatory response. The in vivo administration of compound 29 was sufficient to protect against lipopolysaccharide (LPS)-induced ALI by suppressing the production of inflammatory mediators, including IL-6, TNF-α, and IFN-β, thereby preserving lung tissue integrity. These results substantiate the anti-inflammatory efficacy of compound 29, both in vitro and in vivo, indicating its potential as a promising lead compound in ALI treatment strategies.

Extracellular Vesicles From Mycoplasma gallisepticum: Modulators of Macrophage Activation and Virulence.

Extracellular vesicles (EVs) mediate intercellular communication by transporting proteins. To investigate the pathogenesis of Mycoplasma gallisepticum, a major threat to the poultry industry, we isolated and characterized M. gallisepticum-produced EVs. Our study highlights the significant impact of M. gallisepticum-derived EVs on immune function and macrophage apoptosis, setting them apart from other M. gallisepticum metabolites. These EVs dose-dependently enhance M. gallisepticum adhesion and proliferation, simultaneously modulating Toll-like receptor 2 and interferon γ pathways and thereby inhibiting macrophage activation. A comprehensive protein analysis revealed 117 proteins in M. gallisepticum-derived EVs, including established virulence factors, such as GapA, CrmA, VlhA, and CrmB. Crucially, these EV-associated proteins significantly contribute to M. gallisepticum infection. Our findings advance our comprehension of M. gallisepticum pathogenesis, offering insights for preventive strategies and emphasizing the pivotal role of M. gallisepticum-derived EVs and their associated proteins. This research sheds light on the composition and crucial role of M. gallisepticum-derived EVs in M. gallisepticum pathogenesis, aiding our fight against M. gallisepticum infections.

Orexin A alleviates LPS-induced acute lung injury by inhibiting macrophage activation through JNK-mediated autophagy

Crosstalk between the central nervous system and immune system by the neuroendocrine and autonomic nervous systems is critical during the inflammatory response. Exposure to endotoxin alters the activity of hypothalamic homeostatic systems, resulting in changed transmitter release within the brain. This study investigated the effects and cellular molecular mechanisms of neurogenic and exogenous orexin-A (OXA) in LPS-induced acute lung injury (ALI). We found the production of OXA in the hypothalamus and lungs was both decreased following LPS infection. LPS-induced lung injury including the destruction of the structure, inflammatory cell infiltration, and pro-inflammatory cytokines generation was aggravated in mice in which orexin neurons were lesioned with the neurotoxin orexin-saporin (orexin-SAP). Administration of exogenous OXA greatly improved lung pathology and reduced inflammatory response. Orexin receptors were found in cultured mouse bone marrow-derived macrophages (BMDMs) and lung macrophages (LMs), adoptive transfer of OXA-treated macrophages showed alleviative lung injury compared to adoptive transfer of macrophages without OXA treatment. Mechanistically, it is the induction of autophagy via JNK activation that is responsible for OXA to suppress macrophage-derived pro-inflammatory cytokine production. These findings highlight the importance of neuro-immune crosstalk and indicate that OXA may be a potential therapeutic agent in the treatment of ALI.

FKN secreted by kidney epithelial cells regulates macrophage activation in lupus nephritis via the Hippo signaling pathway.

Lupus nephritis (LN) is a serious complication of systemic lupus erythematosus (SLE), and its pathogenesis is not fully understood. Previously, we showed that fractalkine (FKN) expression was positively correlated with the severity of LN. Here, we aimed to study the role of the Hippo signaling pathway (HSP) and its interaction with FKN in LN in an attempt to provide novel strategies for LN treatment. In this study, lipopolysaccharide (LPS)/interferon-γ (IFN-γ)-stimulated THP-1 cells were co-cultured with FKN up-regulated or down-regulated kidney epithelial cells Hkb20. FKN-knockout (KO-FKN) mice were used to construct LN model. Flow cytometric analysis, quantitative real-time polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), pathological staining, Western blot, and immunofluorescence (IF) staining were employed to investigate the role of FKN and its interaction with the Hippo signaling pathway (HSP) in LN. Up-regulation of FKN in kidney epithelial cells was associated with increased macrophage activation. FKN overexpression in kidney epithelial cells suppressed apoptosis, inflammation levels, and M1 polarization of THP-1 cells and inhibited the HSP. Oppositely, FKN knockdown in kidney epithelial cells increased apoptosis, inflammation, and M1 polarization and activated the HSP. HSP inhibitor reversed the effect of FKN knockdown on THP-1 cells. In LN mice, FKN knockout and YAP inhibitor decreased the levels of renal function markers, alleviated kidney injury induced by LN, and inhibited macrophage activation in LN mice. FKN down-regulation reduced the activation of macrophages in renal tissue and alleviated kidney damage by activating HSP. The regulatory effect of FKN on HSP should be confirmed in patients with LN, and the mechanism of FKN in LN should be further explored.