Synthesis and Characterization of Copper-Crosslinked Carbon Dot Nanoassemblies for Efficient Macrophage Manipulation.

Nanomedicines loaded in macrophages (MAs) can actively target tumors without dominantly relying on the enhanced permeability and retention (EPR) effect, making them effective for treating EPR-deficient malignancies. Herein, copper-crosslinked carbon dot clusters (CDCs) are synthesized with both photodynamic and chemodynamic functions to manipulate MAs, aiming to direct the MA-mediated tumor targeting. First, green fluorescent CDs (g-CDs) are prepared by a one-step hydrothermal method. Subsequently, the g-CDs are complexed with divalent copper ions to form copper-crosslinked CDCs (g-CDCs/Cu), which are incubated with MAs for their manipulation. Experimental results revealed that the prepared g-CDCs/Cu displayed good aqueous dispersibility and fluorescent emission properties. The nanoassemblies can be activated to deplete the overexpressed glutathione (GSH) and generate reactive oxygen species (ROS) in the presence of laser irradiation through the combined Cu-mediated chemodynamic therapy and CD-mediated photodynamic therapy. Furthermore, the ROS produced in MAs enabled polarization of MAs to antitumor M1 phenotype, suggesting the future potential use to reverse the immunosuppressive tumor microenvironment. These results obtained from the current study suggest a significant potential to develop g-CDCs/Cu for GSH depletion, ROS generation, and MA M1 polarization as a theransotic agent to tackle cancer.

mCRP-Induced Focal Adhesion Kinase-Dependent Monocyte Aggregation and M1 Polarization, Which Was Partially Blocked by the C10M Inhibitor.

Monomeric C-reactive protein (mCRP) has recently been implicated in the abnormal vascular activation associated with development of atherosclerosis, but it may act more specifically through mechanisms perpetuating damaged vessel inflammation and subsequent aggregation and internalization of resident macrophages. Whilst the direct effects of mCRP on endothelial cells have been characterized, the interaction with blood monocytes has, to our knowledge, not been fully defined. Here we showed that mCRP caused a strong aggregation of both U937 cell line and primary peripheral blood monocytes (PBMs) obtained from healthy donors. Moreover, this increase in clustering was dependent on focal adhesion kinase (FAK) activation (blocked by a specific inhibitor), as was the concomitant adhesive attachment to the plate, which was suggestive of macrophage differentiation. Confocal microscopy confirmed the increased expression and nuclear localization of p-FAK, and cell surface marker expression associated with M1 macrophage polarization (CD11b, CD14, and CD80, as well as iNOS) in the presence of mCRP. Inclusion of a specific CRP dissociation/mCRP inhibitor (C10M) effectively inhibited PBMs clustering, as well as abrogating p-FAK expression, and partially reduced the expression of markers associated with M1 macrophage differentiation. mCRP also increased the secretion of pro-inflammatory cytokines Interleukin-8 (IL-8) and Interleukin-1ß (IL-1ß), without notably affecting MAP kinase signaling pathways; inclusion of C10M did not perturb or modify these effects. In conclusion, mCRP modulates PBMs through a mechanism that involves FAK and results in cell clustering and adhesion concomitant with changes consistent with M1 phenotypical polarization. C10M has potential therapeutic utility in blocking the primary interaction of mCRP with the cells-for example, by protecting against monocyte accumulation and residence at damaged vessels that may be predisposed to plaque development and atherosclerosis.

Saturated fatty acids synergizes cadmium to induce macrophages M1 polarization and hepatic inflammation.

Exposure to the toxic metal cadmium (Cd) is a well-established risk factor for hepatic inflammation, but it remains unclear how metabolic components, such as different fatty acids (FAs), interact with Cd to influence this process. Understanding these interactions is essential for identifying potential preventative and therapeutic targets for this disorder. To address this question, we conducted in vitro and in vivo studies to investigate the combinatorial effect of Cd and saturated FAs on hepatic inflammation. Specifically, we assessed the cytotoxicity of Cd on macrophages and their polarization and inflammatory activation upon co-exposure to Cd and saturated FAs. Our results showed that while saturated FAs had minimal impact on the cytotoxicity of Cd on macrophages, they significantly collaborated with Cd in predisposing macrophages towards a pro-inflammatory M1 polarization, thereby promoting inflammatory activation. This joint effect of Cd and saturated FAs resulted in persistent inflammation and hepatic steatohepatitis in vivo. In summary, our study identified macrophage polarization as a novel mechanism by which co-exposure to Cd and saturated lipids induces hepatic inflammation. Our findings suggest that intervening in macrophage polarization may be a potential approach for mitigating the adverse hepatic effects of Cd.

Xylan acetate ester ameliorates ulcerative colitis through intestinal barrier repair and inflammation inhibition via regulation of macrophage M1 polarization.

Ulcerative colitis (UC) is a chronic inflammatory disease resulting from abnormal immune response to gut microflora translocating through damaged intestinal barrier. Xylan acetate ester (XylA) can increase colon short-chain fatty acids (SCFAs) levels and alleviate kidney disease by inhibiting inflammation through the G protein-coupled receptor pathway. Here, we synthesized and purified XylA, and then the effects and mechanisms of XylA on dextran sodium sulfate-induced UC in mice were investigated. The results showed that in mice, similar to the positive drug 5-aminosalicylic acid, oral administration of XylA significantly alleviated all UC symptoms, including weight loss, diarrhea, and hematochezia. Further mechanism studies revealed that XylA could repair the damaged colon structure and intestinal barrier function by increasing the expression of tight junction protein zonula occludens 1 and occludin, thus reducing LPS penetration. Moreover, XylA could also restrain intestinal inflammation via inhibiting LPS-TLR4 pathway, downregulating M1 macrophage polarization, and reducing proinflammatory cytokines expression, and in vitro cell experiments showed that these effects may be mediated by XylA derived SCFAs, particularly acetates, propionates and butyrates. All these results suggested that XylA may be a potential improving agent for UC treatment, and natural polysaccharides may represent a novel avenue for drug development of UC.

Sodium houttuyfonate induces bacterial lipopolysaccharide shedding to promote macrophage M1 polarization against acute bacterial lung infection.

Sodium houttuyfonate (SH), derived from the widely utilized natural herb Houttuynia cordata, exhibits an effective therapeutic effect on various diseases, including bacterial and fungal infections, especially the respiratory tract infection. Therefore, the anti-microbial mechanisms of SH may be different from the single-target action mechanism of conventional antibiotics, and further research is needed to clarify this. Firstly, we discovered that SH can effectively intervene in mouse lung infections by reducing bacterial load and acute inflammation response related to pneumonia caused by Pseudomonas aeruginosa. Interestingly, our results confirmed that SH has surface activity and can directly induce changes in the cell wall the shedding of surface lipopolysaccharide (LPS). Additionally, we found that SH-induced shedding of LPS can induce M1 polarization of macrophages in the early stage, leading to the production of corresponding polarization effector molecules. Subsequently, we discovered that SH-induced M1 polarization cells can effectively phagocytose and kill bacterial cells. The protein expression results indicated that SH can enhance the expression of M1 polarization pathway of TLR4/MyD88/NF-κB during the initial phase of macrophage and pathogen interaction. In summary, our results imply that SH could directly induce the shedding of P. aeruginosa LPS in a surfactant-like manner. Afterwards, the SH induced abscisic LPS can initiate the TLR4/MyD88/NF-κB immune pathway to trigger the M1 polarization of macrophages, which might intervene the P. aeruginosa-caused acute lung infection at early stage. Based on these findings, we attempted to coin the term "immune feedback eradication mechanism against pathogen of natural product" to describe this potent antimicrobial mechanism of SH.

IFIH1/IRF1/STAT1 promotes sepsis associated inflammatory lung injury via activating macrophage M1 polarization.

BACKGROUND: A growing body of research has shown that the phenotypic change in macrophages from M0 to M1 is essential for the start of the inflammatory process in septic acute respiratory distress syndrome (ARDS). Potential treatment targets might be identified with more knowledge of the molecular regulation of M1 macrophages in septic ARDS. METHODS: A multi-microarray interrelated analysis of high-throughput experiments from ARDS patients and macrophage polarization was conducted to identify the hub genes associated with macrophage M1 polarization and septic ARDS. Lipopolysaccharide (LPS) and Poly (I:C) were utilized to stimulate bone marrow-derived macrophages (BMDMs) for M1-polarized macrophage model construction. Knock down of the hub genes on BMDMs via shRNAs was used to screen the genes regulating macrophage M1 polarization in vitro. The cecal ligation and puncture (CLP) mouse model was constructed in knockout (KO) mice and wild-type (WT) mice to explore whether the screened genes regulate macrophage M1 polarization in septic ARDS in vivo. ChIP-seq and further experiments on BMDMs were performed to investigate the molecular mechanism. RESULTS: The bioinformatics analysis of gene expression profiles from a clinical cohort of 26 ARDS patients and macrophage polarization found that the 5 hub genes (IFIH1, IRF1, STAT1, IFIT3, GBP1) may have a synergistic effect on macrophage M1 polarization in septic ARDS. Further in vivo investigations indicated that IFIH1, STAT1 and IRF1 contribute to macrophage M1 polarization. The histological evaluation and immunohistochemistry of the lungs from the IRF1-/- and WT mice indicated that knockout of IRF1 markedly alleviated CLP-induced lung injury and M1-polarized infiltration. Moreover, the molecular mechanism investigations indicated that knockdown of IFIH1 markedly promoted IRF1 translocation into the nucleus. Knockout of IRF1 significantly decreases the expression of STAT1. ChIP-seq and PCR further confirmed that IRF1, as a transcription factor of STAT1, binds to the promoter region of STAT1. CONCLUSION: IRF1 was identified as the key molecule that regulates macrophage M1polarization and septic ARDS development in vivo and in vitro. Moreover, as the adaptor in response to infection mimics irritants, IFIH1 promotes IRF1 (transcription factor) translocation into the nucleus to initiate STAT1 transcription.

Osteopontin Promotes Macrophage M1 Polarization by Activation of the JAK1/STAT1/HMGB1 Signaling Pathway in Nonalcoholic Fatty Liver Disease.

Background and Aims: Osteopontin (OPN) is reported to be associated with the pathogenesis of nonalcoholic fatty liver disease (NAFLD). However, the function of OPN in NAFLD is still inconclusive. Therefore, our aim in this study was to evaluate the role of OPN in NAFLD and clarify the involved mechanisms. Methods: We analyzed the expression change of OPN in NAFLD by bioinformatic analysis, qRT-PCR, western blotting and immunofluorescence staining. To clarify the role of OPN in NAFLD, the effect of OPN from HepG2 cells on macrophage polarization and the involved mechanisms were examined by FACS and western blotting. Results: OPN was significantly upregulated in NAFLD patients compared with normal volunteers by microarray data, and the high expression of OPN was related with disease stage and progression. OPN level was also significantly increased in liver tissue samples of NAFLD from human and mouse, and in HepG2 cells treated with oleic acid (OA). Furthermore, the supernatants of OPN-treated HepG2 cells promoted the macrophage M1 polarization. Mechanistically, OPN activated the janus kinase 1(JAK1)/signal transducers and activators of transcription 1 (STAT1) signaling pathway in HepG2 cells, and consequently HepG2 cells secreted more high-mobility group box 1 (HMGB1), thereby promoting macrophage M1 polarization. Conclusions: OPN promoted macrophage M1 polarization by increasing JAK1/STAT1-induced HMGB1 secretion in hepatocytes.

Peimisine ameliorates DSS-induced colitis by suppressing Jak-Stat activation and alleviating gut microbiota dysbiosis in mice.

OBJECTIVES: Inflammatory cytokine secretion and gut microbiota dysbiosis play crucial roles in ulcerative colitis. In this research, the protective effects of peimisine on colitis mice were investigated. METHODS: The protective effects were evaluated by the disease activity index, colonic length, hematoxylin-eosin, and AB/PAS Staining. The protective mechanisms were analyzed by ELISA, Western-blot, immunohistochemistry staining, immunofluorescence staining, and 16S rRNA gene analysis. KEY FINDINGS: The results showed that peimisine treatment could reduce the disease activity index, prevent colonic shortening, and alleviate colon tissue damage. Peimisine treatment also decreased the levels of MCP-1, IL-1ß, IL-6, IFN-γ, TNF-α and affected macrophage polarization and Th17/Treg cell balance by downregulating the expression of jak1/2, p-jak1/2, stat1/3, and p-stat1/3. Moreover, peimisine treatment significantly increased the abundances of beneficial microbes (e.g. Ruminococcaceae UCG-014 and Lachnospiraceae_NK4A136_group) and decreased the abundances of harmful microbes (e.g. Bacteroides and Escherichia). CONCLUSIONS: Peimisine can ameliorate colitis by inhibiting Jak-Stat signaling pathway, reversing gut microbiota alterations, suppressing macrophage M1 polarization, maintaining the Th17/Treg cell balance, and reducing sustained inflammatory cytokines-related inflammatory injury.

Diabetic macrophage small extracellular vesicles-associated miR-503/IGF1R axis regulates endothelial cell function and affects wound healing.

Diabetic foot ulcer (DFU) is a break in the skin of the foot caused by diabetes. It is one of the most serious and debilitating complications of diabetes. The previous study suggested that dominant M1 polarization during DFU could be the leading reason behind impaired wound healing. This study concluded that macrophage M1 polarization predominates in DFU skin tissue. iNOS was increased in HG-induced M1-polarized macrophages; conversely, Arg-1 was decreased. Macrophage pellets after HG stimulation can impair endothelial cell (EC) function by inhibiting cell viability, tube formation and cell migration, indicating M1 macrophage-derived small extracellular vesicles (sEVs) -mediated HUVEC dysfunction. sEVs miR-503 was significantly upregulated in response to HG stimulation, but inhibition of miR-503 in HG-stimulated macrophages attenuated M1 macrophage-induced HUVEC dysfunction. ACO1 interacted with miR-503 and mediated the miR-503 package into sEVs. Under HG stimulation, sEVs miR-503 taken in by HUVECs targeted IGF1R in HUVECs and inhibited IGF1R expression. In HUVECs, miR-503 inhibition improved HG-caused HUVEC dysfunction, whereas IGF1R knockdown aggravated HUVEC dysfunction; IGF1R knockdown partially attenuated miR-503 inhibition effects on HUVECs. In the skin wound model in control or STZ-induced diabetic mice, miR-503-inhibited sEVs improved, whereas IGF1R knockdown further hindered wound healing. Therefore, it can be inferred from the results that the M1 macrophage-derived sEVs miR-503 targets IGF1R in HUVECs, inhibits IGF1R expression, leads to HUVEC dysfunction, and impedes wound healing in diabetic patients, while packaging miR-503 as an M1 macrophage-derived sEVs may be mediated by ACO1.

NF-κB p65 and SETDB1 expedite lipopolysaccharide-induced intestinal inflammation in mice by inducing IRF7/NLR-dependent macrophage M1 polarization.

Macrophages exhibit distinct phenotypes that are pro-inflammatory (M1) or anti-inflammatory (M2) in response to inflammation. In this study, we tried to identify the roles and mechanisms of interferon regulatory factor 7 (IRF7) in modulating the phenotypes of macrophages in lipopolysaccharide (LPS)-induced intestinal inflammation. The mouse model of intestinal inflammation was induced by lipopolysaccharide (LPS), and mouse bone marrow-derived macrophages (BMDMs) and mouse intestinal epithelial cells were selected for experimental verification in vitro. Results demonstrated that IRF7 was highly expressed in the mouse model of intestinal inflammation, while IRF7 deficiency repressed macrophage M1 polarization and attenuated intestinal inflammation in mice. p65 and SET domain bifurcated 1 (SETDB1) synergistically promoted histone 3 lysine 4 trimethylation (H3K4me3) methylation to elevate IRF7 expression, which activated the Nod-like receptor (NLR) pathway to induce macrophage M1 polarization. Through this mechanism, IRF7 in BMDMs functioned to accelerate intestinal epithelial cell apoptosis and their release of pro-inflammatory proteins. Furthermore, the promoting effect of p65 and SETDB1 on LPS-induced intestinal inflammation was validated in vivo. To sum up, NF-κB p65 and SETDB1 facilitated IRF7-mediated macrophage M1 polarization, thereby aggravating the LPS-induced intestinal inflammation. Hence, this study highlights the appealing value of these factors as anti-inflammatory targets.

Ferroptotic cardiomyocyte-derived exosomes promote cardiac macrophage M1 polarization during myocardial infarction.

Ferroptosis is a mode of cell death that occurs in myocardial infarction (MI). Signals emanating from apoptotic cells are able to induce macrophage polarization through exosome-loading cargos, which plays a vital role in the process of disease. However, whether ferroptotic cardiomyocytes derived exosome (MI-Exo) during MI act on macrophage polarization and its mechanism remain unclear. In this study, a MI mouse model was established, and cardiac function evaluation and pathological staining were performed. The effect of MI-Exo on polarization of RAW264.7 cells was assessed by the expression of IL-10 and NOS2. Ferroptosis inhibitor of ferrostatin-1 was used to verify whether MI-Exo function was dependents on ferroptosis. Cardiac function and myocardial histomorphology were markedly impaired and massive immune cell infiltration in MI mice, compared with the sham group. The significantly increased MDA content and Fe2+ accumulation in the heart tissue of MI mice suggested cardiomyocyte ferroptosis. Compared with the sham group, the expression of M1 marker NOS2 was significantly up-regulated and M2 marker IL-10 was significantly down-regulated in the heart tissue of MI mice. Exosome-derived from MI HL-1 cell-treated with ferrostatin-1 (Fer-1-Exo) and MI-Exo were internalized by RAW 264.7 cells. Compared with culture alone, co-cultured with MI-Exo significantly promoted NOS2 expression and suppressed IL-10 expression, and decreased proportion of Arginase-1-labeled M2 macrophages, also inhibited phagocytosis of RAW 264.7 cells. Wnt1 and ß-cantenin expression also elevated after treated with MI-Exo. However, co-cultured with Fer-1-Exo significantly reversed the above changes on RAW 264.7 cells induced by MI-Exo. In conclusion, ferroptotic cardiomyocytes-derived exosome crosstalk macrophage to induce M1 polarization via Wnt/ß-cantenin pathway, resulting in pathological progress in MI. This understanding provides novel therapeutic target for MI.

The Construction of ITP Diagnostic Modeling Based on the Expressions of Hub Genes Associated with M1 Polarization of Macrophages.

Purpose: Primary immune thrombocytopenia (ITP) is an immune disease with a diagnosis of exclusion, since no validated biomarkers have been identified. In this study, we explored biomarkers associated with the development of ITP from an immune perspective to inform the clinical diagnosis. Patients and Methods: Differentially expressed genes (DEGs) between normal and ITP samples were analyzed using limma package. Random forest algorithm and LASSO regression were further used to screen for DEGs associated with ITP. The expression of these hub genes was validated by PCR. The relationship between DEGs and immunity was explored by enrichment analysis. Immune cell infiltration in ITP was analyzed by CIBERSORT and ssGSEA, and the relationship between DEGs and infiltrating immune cells was analyzed by Spearman's rank correlation analysis. Finally, a diagnostic model related to DEGs was constructed by the neural network, and its efficiency was detected by the ROC curve. Results: After screening the GEO database and validation by PCR analysis, The expression of CTH and TAF8 were higher and while OSBP2 expression was lower in ITP patients compared to normal subjects (P<0.05). GO enrichment analysis showed that these DEGs were associated with inflammatory immune-related diseases, and KEGG analysis showed that they mainly regulated signaling pathways such as JAK-STAT. CIBERSORT and ssGSEA analyses showed that these DEGs were mainly associated with macrophage M1 polarization. The expression of CTH and TAF8 were positively correlated with M1 expression, while OSBP2 was negatively correlated with M1 expression. The ROC curve showed high accuracy of the neural network model [AUC= 0.939, 95% CI (0.8-1)]. Conclusion: Our results suggest that CTH, TAF8, and OSBP2 can be used as effective diagnostic biomarkers of ITP.

Tubuloside B, isolated from Cistanche tubulosa, a promising agent against M1 macrophage activation via synergistically targeting Mob1 and ERK1/2.

Targeting macrophage M1 polarization is a promising strategy with fewer detrimental effects in COVID-19 curation. Phenylethanoid glycosides (PhGs) of Cistanche tubulosa are a botanical drug to possess various anti-inflammation-related functions, such as immunomodulating, hepatoprotective or neuroprotective functions, whereas their anti-inflammatory activity is rarely understood. A search into their anti-inflammatory characteristics led to the isolation of 49 PhGs along with 15 new PhGs. Their inhibitory effects against M1 polarization induced by LPS plus IFN-γ were explored in RAW264.7 macrophages. Of these PhGs, tubuloside B (Tub B) exerted substantial NO scavenging effect both in chemical- and cell-based assays, and it inhibited massive production of cytokines and chemokines. Tub B decreased ERK1/2 phosphorylation via direct binding and inhibited the MAPK signaling pathway. Tub B also directly binded to Mob1 protein, thereby increased the stability and level of Mob1 protein by inhibiting ubiquitinated degradation. Mob1 was pivotal for the anti-inflammatory activity of Tub B, and it acted independently of the canonical Hippo-YAP pathway. Moreover, ERK1/2 and Mob1 also had a synergic effect on modulating the inflammatory response. Finally, these effects of Tub B were verified in mice with LPS-induced systemic inflammatory response syndrome. Taken together, these results indicated that Tub B acted as a promising agent against M1 macrophage activation by synergistically targeting ERK1/2 and Mob1, and that it may potentially be a drug candidate to prevent/treat inflammatory diseases, especially in COVID-19.

M1 macrophage-derived extracellular vesicle containing tsRNA-5006c promotes osteogenic differentiation of aortic valve interstitial cells through regulating mitophagy.

Background: Osteogenic differentiation of aortic valve interstitial cells (AVICs) plays a key role in the calcific aortic valve disease progression. Extracellular vesicles (EVs)-derived from M1-polarized macrophages (M1-EVs) orchestrated intercellular communication by delivering non-coding RNAs such as tRNA-derived small RNAs (tsRNAs) is crucial for cardiovascular disease. However, the role and mechanism of M1-EVs tsRNAs in osteogenic differentiation of AVICs remains largely unclear. Methods: M1-EVs and PBS treated-RAW 264.7 cell-derived EVs (NC-EVs) were incubated with AVICs and subjected to small RNA sequencing. Candidate tsRNA in M1-EVs was silenced to explore their effects on AVIC osteogenic differentiation and mitophagy. Results: DiI-labeled M1-EVs were internalized by AVICs, resulting in significantly increased calcium nodule formation and expression of osteogenesis-related genes in AVICs, including RUNX2, BMP2, osteopontin, and SPP1, compared with NC-EVs. Small RNA sequencing revealed that 17 tsRNAs were significantly up-regulated such as tsRNA-5006c, while 28 tsRNAs were significantly down-regulated in M1-EVs compared with NC-EVs. Intriguingly, tsRNA-5006c-deleted M1-EVs treatment significantly reduced calcium nodule formation and expression of osteogenesis-related genes in AVICs relative to control group. Moreover, target genes of tsRNA-5006c were mainly involved in autophagy-related signaling pathways, such as MAPK, Ras, Wnt, and Hippo signaling pathway. Hallmarks of mitophagy activation in AVICs including mitophagosome formation, TMRM fluorescence, expression of LC3-II, BINP3, and PGC1α, were significantly elevated in the M1-EVs group compared with NC-EVs group, whereas M1-EVs tsRNA-5006c inhibitor led to a significant reduction in these indicators. Conclusion: M1-EVs carried tsRNA-5006c regulates AVIC osteogenic differentiation from the perspective of mitophagy, and we provide a new target for the prevention and treatment of aortic valve calcification.

Melatonin alleviates PM2.5-triggered macrophage M1 polarization and atherosclerosis via regulating NOX2-mediated oxidative stress homeostasis.

It is reported that oxidative stress homeostasis was involved in PM2.5-induced foam cell formation and progression of atherosclerosis, but the exact molecular mechanism is still unclear. Melatonin is an effective antioxidant that could reverse the cardiopulmonary injury. The main purpose of this study is to investigate the latent mechanism of PM2.5-triggered atherosclerosis development and the protective role of melatonin administration. Vascular Doppler ultrasound showed that PM2.5 exposure reduced aortic elasticity in ApoE-/- mice. Meanwhile, blood biochemical and pathological analysis demonstrated that PM2.5 exposure caused dyslipidemia, elicited oxidative damage of aorta and was accompanied by an increase in atherosclerotic plaque area; while the melatonin administration could effectively alleviate PM2.5-induced macrophage M1 polarization and atherosclerosis in mice. Further investigation verified that NADPH oxidase 2 (NOX2) and mitochondria are two prominent sources of PM2.5-induced ROS production in vascular macrophages. Whereas, the combined use of two ROS-specific inhibitors and adopted with melatonin markedly rescued PM2.5-triggered macrophage M1 polarization and foam cell formation by inhibiting NOX2-mediated crosstalk of Keap1/Nrf2/NF-κB and TLR4/TRAF6/NF-κB signaling pathways. Our results demonstrated that NOX2-mediated oxidative stress homeostasis is critical for PM2.5-induced atherosclerosis and melatonin might be a potential treatment for air pollution-related cardiovascular diseases.

Tyrosine kinase nonreceptor 1 (TNK1) knockdown ameliorates hemorrhage shock-induced kidney injury via inhibiting macrophage M1 polarization.

Hemorrhage shock (HS) is a major threat to patients with trauma and spontaneous bleeding, resulting in multi-organ failure including the kidney. Tyrosine kinase nonreceptor 1 (TNK1) has been shown to be upregulated in the kidney of experimental HS and patients with severe trauma. The study aims to investigate the role of TNK1 and the underlying mechanism in HS-induced kidney injury. A model of HS was established with femoral artery bloodletting, followed by resuscitation in Sprague-Dawley rats. Renal expression of TNK1 was abnormally induced by HS in rats. Knockdown of TNK1 alleviated HS-induced cell apoptosis and the level of proinflammatory cytokines (TNF-α, IL-6 and IL-1ß) in the kidney. The expression of M1 macrophage markers (CD86 and iNOS) and the activation of STAT1 were inhibited by TNK1 knockdown in HS rats. In vitro, human monocyte THP-1 cells were treated with 20 ng/mL interferon-gamma plus 100 ng/mL lipopolysaccharide to induce M1 polarization. TNK1 knockdown exerted inhibitory effect on macrophage M1 polarization, M1-type inflammatory cytokine production and STAT1 activation in THP-1 cells. In conclusion, downregulation of TNK1 alleviates HS-induced kidney injury by suppressing macrophage M1 polarization, inflammation and kidney cell apoptosis, in which the deactivation of STAT1 signaling may be involved.

Loganin inhibits macrophage M1 polarization and modulates sirt1/NF-κB signaling pathway to attenuate ulcerative colitis.

Loganin, a major bioactive iridoid glycoside derived from Cornus officinalis, exerts different beneficial biological properties. Recently, loganin has been reported to exhibit potential anti-inflammatory effects in the intestinal tissues, while the detailed mechanisms remain elusive. This study aimed to investigate whether loganin could inhibit the inflammatory response in dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) and to explore possible molecular mechanisms involved in this process. Results showed that oral administration of loganin significantly decreased body weight loss, disease activity index, colon shortening, myeloperoxidase (MPO) activity and pathologic abnormalities in UC mice. Loganin obviously inhibited the mRNA and protein levels of IL-6, TNF-α and IL-1ß in colon tissues from UC mice. Furthermore, loganin remarkably reduced macrophage M1 polarization in UC mice evidenced by reduced the number of F4/80 and iNOS dual-stained M1 macrophages, and the expression of M1 macrophage-related pro-inflammatory chemokines/cytokines including MCP-1, CXCL10 as well as COX-2. Further investigation showed that loganin upregulated the mRNA and protein levels of Sirt1, with the inhibition of NF-κB-p65 acetylation in colon tissues from UC mice. Moreover, Sirt1-specific inhibitor Ex527 administration abolished the anti-inflammatory and anti-macrophage M1 polarization effects of loganin in UC. Thus, loganin could inhibit M1 macrophage-mediated inflammation and modulate Sirt1/NF-κB signaling pathway to attenuate DSS-induced UC. Loganin was considered as a viable natural strategy in the treatment of UC.[Figure: see text].

ß­glucan, a dectin­1 ligand, promotes macrophage M1 polarization via NF­κB/autophagy pathway.

Pro­inflammatory (M1) macrophages have key roles in atherogenesis. As ß­glucan has been demonstrated to exert pro­inflammatory effects, the present study examined whether ß­glucan exerts atherogenic effects via converting macrophages into M1 phenotype. The results from reverse transcription­quantitative polymerase chain reaction, flow cytometry, western blotting and transmission electron microscope indicated that M1 macrophage markers inducible nitric oxide synthase and cluster of differentiation 80 were upregulated, dectin­1 (a receptor for ß­glucan) expression and nuclear factor (NF)­κB nuclear translocation were promoted, and autophagy level was inhibited following ß­glucan treatment of macrophages. Additionally, dectin­1 small interfering RNA (siRNA), autophagy inducer rapamycin and NF­κB inhibitor SN50 reversed the effects of ß­glucan on autophagy level and macrophage M1 polarization, suggesting that dectin­1 and NF­κB are upstream of autophagy in ß­glucan­induced macrophage M1 polarization. Notably, simultaneous treatment with dectin­1 siRNA and SN50 exhibited similar effects on ß­glucan­reduced autophagy compared with dectin­1 siRNA treatment alone. These findings demonstrate that dectin­1 may mediate ß­glucan­reduced autophagy through NF­κB in macrophages. Accordingly, results from hematoxylin and eosin staining, western blotting and immunofluorescence staining demonstrated that ß­glucan accelerated the progress of atherosclerosis in apolipoprotein E­deficient mice and modulated expression of dectin­1, beclin­1 and light chain 3II/I in aortas similarly to that observed in macrophages. These results indicate that dectin­1 activation by ß­glucan exerts atherogenic effects via converting macrophages into M1 phenotype in an NF­κB­autophagy­dependent pathway.