Knockout of C6orf120 in Rats Alleviates Concanavalin A-induced Autoimmune Hepatitis by Regulating Macrophage Polarization

Objective The effect of the functionally unknown gene C6orf120 on autoimmune hepatitis was investigated on C6orf120 knockout rats(C6orf120^(-/-))and THP-1 cells.Method Six–eight-week-old C6orf120^(-/-)and wild-type(WT)SD rats were injected with Con A(16 mg/kg),and euthanized after 24 h.The sera,livers,and spleens were collected.THP-1 cells and the recombinant protein(rC6ORF120)were used to explore the mechanism in vitro.The frequency of M1 and M2 macrophages was analyzed using flow cytometry.Western blotting and PCR were used to detect macrophage polarization-associated factors.Results C6orf120 knockout attenuated Con A-induced autoimmune hepatitis.Flow cytometry indicated that the proportion of CD68^(+)CD86^(+)M1 macrophages from the liver and spleen in the C6orf120^(-/-)rats decreased.C6orf120 knockout induced downregulation of CD86 protein and the mRNA levels of related inflammatory factors TNF-α,IL-1β,and IL-6 in the liver.C6orf120 knockout did not affect the polarization of THP-1 cells.However,rC6ORF120 promoted the THP-1 cells toward CD68^(+)CD80^(+)M1 macrophages and inhibited the CD68^(+)CD206^(+)M2 phenotype.Conclusion C6orf120 knockout alleviates Con A-induced autoimmune hepatitis by inhibiting macrophage polarization toward M1 macrophages and reducing the expression of related inflammatory factors in C6orf120^(-/-)rats.

Th17/Treg balance and macrophage polarization ratio in lower extremity arteriosclerosis obliterans

Objective:To explore the balance of peripheral blood T helper 17 cells/regulatory T cell(Th17/Treg)ratio and the polarization ratio of M1 and M2 macrophages in lower extremity arteriosclerosis obliterans(ASO).Methods:A rat model of lower extremity ASO was established,and blood samples from patients with lower extremity ASO before and after surgery were obtained.ELISA was used to detect interleukin 6(IL-6),IL-10,and IL-17.Real-time RCR and Western blot analyses were used to detect Foxp3,IL-6,IL-10,and IL-17 expression.Moreover,flow cytometry was applied to detect the Th17/Treg ratio and M1/M2 ratio.Results:Compared with the control group,the iliac artery wall of ASO rats showed significant hyperplasia,and the concentrations of cholesterol and triglyceride were significantly increased(P<0.01),indicating the successful establishment of ASO.Moreover,the levels of IL-6 and IL-17 in ASO rats were pronouncedly increased(P<0.05),while the IL-10 level was significantly decreased(P<0.05).In addition to increased IL-6 and IL-17 levels,the mRNA and protein levels of Foxp3 and IL-10 in ASO rats were significantly decreased compared with the control group.The Th17/Treg and M1/M2 ratios in the ASO group were markedly increased(P<0.05).These alternations were also observed in ASO patients.After endovascular surgery(such as percutaneous transluminal angioplasty and arterial stenting),all these changes were significantly improved(P<0.05).Conclusions:The Th17/Treg and M1/M2 ratios were significantly increased in ASO,and surgery can effectively improve the balance of Th17/Treg,and reduce the ratio of M1/M2,and the expression of inflammatory factors.

Scavenger receptor A-mediated nanoparticles target M1 macrophages for acute liver injury

Acute liver injury(ALI)has an elevated fatality rate due to untimely and ineffective treatment.Although,schisandrin B(SchB)has been extensively used to treat diverse liver diseases,its therapeutic efficacy on ALI was limited due to its high hydrophobicity.Palmitic acid-modified serum albumin(PSA)is not only an effective carrier for hydrophobic drugs,but also has a superb targeting effect via scavenger receptor-A(SR-A)on the M1 macrophages,which are potential therapeutic targets for ALI.Compared with the common macrophage-targeted delivery systems,PSA enables site-specific drug delivery to reduce off-target toxicity.Herein,we prepared SchB-PSA nanoparticles and further assessed their therapeutic effect on ALI.In vitro,compared with human serum albumin encapsulated SchB nanoparticles(SchB-HSA NPs),the SchB-PSA NPs exhibited more potent cytotoxicity on lipopolysaccharide(LPS)stimulated Raw264.7(LAR)cells,and LAR cells took up PSA NPs 8.79 times more than HSA NPs.As expected,the PSA NPs also accumulated more in the liver.Moreover,SchB-PSA NPs dramatically reduced the activation of NF-κB signaling,and significantly relieved inflammatory response and hepatic necrosis.Notably,the high dose of SchB-PSA NPs improved the survival rate in 72 h of ALI mice to 75%.Hence,SchB-PSA NPs are promising to treat ALI.

Growth differentiation factor 11 promotes macrophage polarization towards M2 to attenuate myocardial infarction via inhibiting Notch1 signaling pathway

Background:Myocardial infarctions(MI)is a major threat to human health especially in people exposed to cold environment.The polarization of macrophages towards different functional phenotypes(M1 macrophages and M2 macrophages)is closely related to MI repairment.The growth differentiation factor 11(GDF11)has been reported to play a momentous role in inflammatory associated diseases.In this study,we examined the regulatory role of GDF11 in macrophage polarization and elucidated the underlying mechanisms in MI.Methods:In vivo,the mice model of MI was induced by permanent ligation of the left anterior descending coronary artery(LAD),and mice were randomly divided into the sham group,MI group,and MI+GDF11 group.The protective effect of GDF11 on myocardial infarction and its effect on macrophage polarization were verified by echocardiography,triphenyl tetrazolium chloride staining and immunofluorescence staining of heart tissue.In vitro,based on the RAW264.7 cell line,the effect of GDF11 in promoting macrophage polarization toward the M2 type by inhibiting the Notch1 Signaling pathway was validated by qRT-PCR,Western blot,and flow cytometry.Results:We found that GDF11 was significantly downregulated in the cardiac tissue of MI mice.And GDF11 supplementation can improve the cardiac function.Moreover,GDF11 could reduce the proportion of M1 macrophages and increase the accumulation of M2 macrophages in the heart tissue of MI mice.Furthermore,the cardioprotective effect of GDF11 on MI mice was weakened after macrophage clearance.At the cellular level,application of GDF11 could inhibit the expression of M1 macrophage(classically activated macrophage)markers iNOS,interleukin(IL)-1β,and IL-6 in a dose-dependent manner.In contrast,GDF11 significantly increased the level of M2 macrophage markers including IL-10,CD206,arginase 1(Arg1),and vascular endothelial growth factor(VEGF).Interestingly,GDF11 could promote M1 macrophages polarizing to M2 macrophages.At the molecular level,GDF11 significantly down-regulated the Notch1 signaling pathway,the activation of which has been demonstrated to promote M1 polarization in macrophages.Conclusions:GDF11 promoted macrophage polarization towards M2 to attenuate myocardial infarction via inhibiting Notch1 signaling pathway.

Mechanism of Qishen Decoction inhibition of macrophage M1 type polarization by targeting TGR5-mediated NLRP3 inflammasome

Objective:To observe the effect of Qishen decoction on TGR5-mediated activation of NLRP3 inflammasome,so as to clarify the molecular mechanism of its inhibition of macrophage M1-type polarisation to ameliorate non-alcoholic steatohepatitis;Methods:Mouse macrophage cell line RAW264.7 was randomly divided into a control group,model group,Qishen decoction group,TGR5 agonist group and Qishen decoction+TGR5 agonist group.Except for the control group,the remaining groups were constructed the macrophage NLRP3 activation model by palmitic acid induction,and the corresponding drugs were given to intervene.ELISA was used to detect the levels of TNF-α,IL-6,IL-1βand CXCL2 in macrophage supernatants,flow cytometry was used to detect the expression levels of macrophage polarisation marker molecules CD86 and iNOS,and Western blot was used to detect the expression of the TGR5/STAT1/STAT6 signaling pathway and the expression of NLRP3 inflammasome-associated proteins,respectively.Results:Compared with the control group,the contents of macrophages TNF-α,IL-6,IL-1β,CXCL2 and the proportion of macrophages with positive expression of CD86 and iNOS were significantly increased in the model group,and the differences were all statistically significant(P<0.01).Compared with the model group,the contents of TNF-α,IL-6,IL-1β,CXCL2 and the proportion of macrophages with positive expression of CD86 and iNOS were significantly decreased in the Qishen decoction group,and the differences were all statistically significant(P<0.01).In addition,the expression of NLRP3 and Pro-IL-1βproteins in the macrophage lysate and the expression of Caspase-1 p10,Caspase-1 p20 and IL-1βp17 proteins in the cell supernatant of the model group were significantly increased when compared with the control group,and the differences were all statistically significant(P<0.01).Compared with the model group,the expression of NLRP3 and Pro-IL-1βproteins in macrophage lysate and the expression of Caspase-1 p10,Caspase-1 p20 and IL-1βp17 proteins in cell supernatant of the Qishen decoction were significantly reduced,and the differences were all statistically significant(P<0.01);Conclusion:Qishen decoction can inhibit the activation of NLRP3 inflammasome in macrophages by inhibiting the TGR5/STAT1/STAT6 signaling pathway,thereby inhibiting macrophage M1 polarization and improving inflammatory response.

RANKL-induced M1 macrophages are involved in bone formation

The activation of M1 macrophages can be achieved by stimulating them with lipopolysaccharide （LPS） and interferon-γ （IFN-γ）. However, M1 can be found under physiological conditions without any pathological stimuli. This study aimed to understand the involvement of RANKL-induced M1 macrophages in bone formation compared with pathologically induced macrophages. Fischer rats were used to investigate macrophage distribution in normal and injured femoral condyles in vivo. Bone marrow-derived macrophages （BMDMs） were activated with LPS＋IFN-γ and RANKL to achieve M1 activation in vitro. Gene expression related to inflammation, osteoclastogenesis, angiogenesis, and migration was determined by reverse transcription-quantitative polymerase chain reaction （RT-qPCR） and fluorescence-activated cell sorting （FACS）. Tissue macrophages showed distinct expression patterns at different bone regions. RANKL was found in close proximity to inducible nitric oxide synthase-positive （iNOS＋） cells in vivo, suggesting an association between RANKL expression and iNOS＋ cells, especially in trabecular bone. RANKL-induced macrophages showed a different cytokine secretion profile compared with pathologically induced macrophages. Both osteoclasts and M1 macrophages peaked on day 7 during bone healing. RANKL could trigger Ml-like macrophages with properties that were different from those of LPS＋IFN-γ-induced macrophages. These RANKL-activated M1 macrophages were actively involved in bone formation.

Are M1 and M2 macrophages Effectual Players in Pathological Conditions?

Pathologic inflammatory conditions are frequently correlated with dynamic alterations through macrophage activation,with classically activated Ml cells associated with promoting and sustaining inflammation and M2 cells implicated in resolving or smoldering chronic inflammation.Inflammation is a common feature of various chronic diseases,and it has direct involvement in the emergence and progression of these conditions.Macrophages participate in an autoregulatory loop characterizing inflammatory process,as they produce a wide range of biologically active mediators that exert either deleterious or beneficial effects during inflammation.Therefore,balancing the ratio of M1/M2 macrophages can help to ameliorate the inflammatory landscape of pathological conditions.This review will explore the role of macrophage polarization in distant pathological inflammatory conditions,such as cancer,autoimmunity,renal inflammation,stroke,and atherosclerosis,while sharing macrophage-driven pathogenesis.

Polarization of M1 tumor associated macrophage promoted by the activation of TLR3 signal pathway

Objective: To investigate the correlation between activation of toll-like receptors 3(TLR3) signaling pathway and tumor-associated macrophage and its effect on the tumor growth. Methods: The mice Lewis lung cancer cell lines 3LL and melanoma B16H10 were used to construct the subcutaneous transplantation tumor models and then they were treated with Poly-ICLC. The curative effect was observed and then the T cell and macrophage phenotypes infiltrated in local tumor were detected by flow cytometry. After the in vitro culture of mouse bone marrow-derived macrophage, the real-time PCR and western blot were applied to detect the expression of macrophage activation markers and the activation of intracellular signaling pathways. Results: The survival time of mice with brown tumor treated with Poly-ICLC significantly increased and the tumor growth was inhibited. The ratio of local tumor-infiltrated Treg decreased, while the ratio of CD8+ T cell increased significantly. The macrophages surface CD206 expression was down-regulated while the expression of i NOS increased. The Poly-ICLC could promote the expression of M1 markers(IL-1毬, TNF-α毩 and i NOS) in bone marrow-derived macrophage and inhibited the expression of M2 molecules(Arg-1, YM-1 and CD206). The phosphorylation level of downstream p65, TBK1 and IRF3 increased significantly. Conclusions: The Poly-ICLC can activate the TLR3 downstream signaling pathway to induce a M1 polarization of tumor associated macrophage, thereby inhibiting the tumor growth.

Mechanisms of the alternative activation of macrophages and non-coding RNAs in the development of radiation-induced lung fibrosis

Radiation-induced lung fibrosis(RILF) is a common side effect of thoracic irradiation therapy and leads to high mortality rates after cancer treatment. Radiation injury induces inflammatory M1 macrophage polarization leading to radiation pneumonitis, the first stage of RILF progression. Fibrosis occurs due to the transition of M1 macrophages to the anti-inflammatory pro-fibrotic M2 phenotype, and the resulting imbalance of macrophage regulated inflammatory signaling. Non-coding RNA signaling has been shown to play a large role in the regulation of the M2 mediated signaling pathways that are associated with the development and progression of fibrosis. While many studies show the link between M2 macrophages and fibrosis, there are only a few that explore their distinct role and the regulation of their signaling by non-coding RNA in RILF. In this review we summarize the current body of knowledge describing the roles of M2 macrophages in RILF, with an emphasis on the expression and functions of non-coding RNAs.

sDR5-Fc inhibits macrophage M1 polarization by blocking the glycolysis

BACKGROUND M1 polarization of macrophages is an important pathological process in myocardial ischemia reperfusion injury, which is the major obstacle for the treatment of acute myocardial infarction. Currently, the strategies and mechanisms of inhibiting M1 polarization are poorly explored. This study aims to investigate the role of soluble death receptor 5-Fc(s DR5-Fc) in regulating M1 polarization of macrophages under extreme conditions and explore the mechanisms from the aspect of glycolysis.METHODS Extreme conditions were induced in RAW264.7 cells. Real-time quantitative polymerase chain reaction and western blot were used to detect the expression of m RNA and proteins, respectively. Cell counting kit-8 was used to investigate the proliferation activity of cells. Expression levels of inflammatory cytokines were determined by enzyme-linked immunosorbent assay.RESULTS We found that s DR5-Fc rescues the proliferation of macrophages under extreme conditions, including nutrition deficiency, excessive peroxide, and ultraviolet irradiation. In addition, administration of s DR5-Fc inhibits the M1 polarization of macrophages induced by lipopolysaccharide(LPS) and interferon-gamma(IFN-γ), as the expression of M1 polarization markers CD86, CXC motif chemokine ligand 10, matrix metalloproteinase 9, and tumor necrosis factor-α, as well as the secretion of inflammatory factors interleukin(IL)-1β and IL-6, were significantly decreased. By further investigation of the mechanisms, the results showed that s DR5-Fc can recover the LPS and IFN-γ induced p H reduction, lactic acid elevation, and increased expression of hexokinase 2 and glucose transporter 1, which were markers of glycolysis in macrophages.CONCLUSIONS s DR5-Fc inhibits the M1 polarization of macrophages by blocking the glycolysis, which provides a new direction for the development of strategies in the treatment of myocardial ischemia reperfusion injury.

Microglia:a promising therapeutic target in spinal cord injury

Microglia are present throughout the central nervous system and are vital in neural repair,nutrition,phagocytosis,immunological regulation,and maintaining neuronal function.In a healthy spinal cord,microglia are accountable for immune surveillance,however,when a spinal cord injury occurs,the microenvironment drastically changes,leading to glial scars and failed axonal regeneration.In this context,microglia vary their gene and protein expression during activation,and proliferation in reaction to the injury,influencing injury responses both favorably and unfavorably.A dynamic and multifaceted injury response is mediated by microglia,which interact directly with neurons,astrocytes,oligodendrocytes,and neural stem/progenitor cells.Despite a clear understanding of their essential nature and origin,the mechanisms of action and new functions of microglia in spinal cord injury require extensive research.This review summarizes current studies on microglial genesis,physiological function,and pathological state,highlights their crucial roles in spinal cord injury,and proposes microglia as a therapeutic target.

Picroside Ⅱ promotes HSC apoptosis and inhibits the cholestatic liver fibrosis in Mdr2^(−/−)mice by polarizing M1 macrophages and balancing immune responses

Liver fibrosis is characterized by chronic inflammatory responses and progressive fibrous scar formation.Macrophages play a central role in the pathogenesis of hepatic fibrosis by reconstructing the immune microenvironment.Picroside Ⅱ(PIC Ⅱ),extracted from Picrorhizae Rhizoma,has demonstrated therapeutic potential for various liver damage.However,the mechanisms by which macrophage polarization initiates immune cascades and contributes to the development of liver fibrosis,and whether this process can be influenced by PIC Ⅱ,remain unclear.In the current study,RNA sequencing and multiple molecular approaches were utilized to explore the underlying mechanisms of PIC Ⅱ against liver fibrosis in multidrug-resistance protein 2 knockout(Mdr2^(−/−))mice.Our findings indicate that PIC Ⅱ activates M1-polarized macrophages to recruit natural killer cells(NK cells),potentially via the CXCL16-CXCR6 axis.Additionally,PIC Ⅱ promotes the apoptosis of activated hepatic stellate cells(aHSCs)and enhances the cytotoxic effects of NK cells,while also reducing the formation of neutrophil extracellular traps(NETs).Notably,the anti-hepatic fibrosis effects associated with PIC Ⅱ were largely reversed by macrophage depletion in Mdr2^(−/−)mice.Collectively,our research suggests that PIC Ⅱ is a potential candidate for halting the progression of liver fibrosis.

EFFECTS OF ACUMOXI ON IL2-IFN-NKC IMMUNOREGULATORY NETWORK AND ITS RELATED MACROPHAGE-IL1-Th NETWORK AND ON TUMOR——Observation on the Effect of Acumoxi on the Macrophage-IL1-Th Network and on the Metastasis of Hepatoma

Objective: To observe the effect of acumoxi (acupuncture and moxibustion) on macrophage (Mφ)-lL1-Th net-work and hydroperitoneum hepatoma (H 22) metastasis in mice. Methods: A total of 36 BALB/ c male mice bearing H 22 are randomly divided into control, acupuncture and acumoxi groups with 12 cases in each group. In the later 2 groups, Dazhui (GV 14) and Guanyuan (CV 4) are punctured once daily, continuously for 18 days, and in acumoxi group, the two acupoints were also moxibustioned alternatively with moxa stick once every day. After killing the mice, the tissue samples of the 3 groups are treated routinely step by step and analyzed by means of colorimetric analysis for determining the phagocytic function of the macrophages; and the content of IL1 of the Mφ supernatant is assayed with serum plate agglutination (SPA)-Ig floral hoop method of T helper cell (Th) monoclonal antibody; the weight of the reniportal lymph node, the kidney and the lung, and the number of the cancerous nodes on the pulmonary surface are calculated. Results: After acupuncture and moxibustion treatment, the immunoregulatory network indices of acumoxi group increase obviously compared with those of control group(P<0.01), showing an anti-metastasis effect of acumoxi on H 22. Conclusion: Results of the present study and those of our former research prove that acupuncture and moxibustion can suppress the tumor growth and H 22 metastasis by the enhancement of the immunoregulatory network.

MST4 kinase regulates immune thrombocytopenia by phosphorylating STAT1-mediated M1 polarization of macrophages

Primary immune thrombocytopenia(ITP)is an autoimmune hemorrhagic disorder in which macrophages play a critical role.Mammalian sterile-20-like kinase 4(MST4),a member of the germinal-center kinase STE20 family,has been demonstrated to be a regulator of inflammation.Whether MST4 participates in the macrophage-dependent inflammation of ITP remains elusive.The expression and function of MST4 in macrophages of ITP patients and THP-1 cells,and of a macrophage-specific Mst4−/−(Mst4ΔM/ΔM)ITP mouse model were determined.Macrophage phagocytic assays,RNA sequencing(RNA-seq)analysis,immunofluorescence analysis,coimmunoprecipitation(co-IP),mass spectrometry(MS),bioinformatics analysis,and phosphoproteomics analysis were performed to reveal the underlying mechanisms.The expression levels of the MST4 gene were elevated in the expanded M1-like macrophages of ITP patients,and this elevated expression of MST4 was restored to basal levels in patients with remission after high-dose dexamethasone treatment.The expression of the MST4 gene was significantly elevated in THP-1-derived M1 macrophages.Silencing of MST4 decreased the expression of M1 macrophage markers and cytokines,and impaired phagocytosis,which could be increased by overexpression of MST4.In a passive ITP mouse model,macrophage-specific depletion of Mst4 reduced the numbers of M1 macrophages in the spleen and peritoneal lavage fluid,attenuated the expression of M1 cytokines,and promoted the predominance of FcγRIIb in splenic macrophages,which resulted in amelioration of thrombocytopenia.Downregulation of MST4 directly inhibited STAT1 phosphorylation,which is essential for M1 polarization of macrophages.Our study elucidates a critical role for MST4 kinase in the pathology of ITP and identifies MST4 kinase as a potential therapeutic target for refractory ITP.

Morphofunctional Characteristics of Pulmonary Surfactant System and Its Effect on Immune Cells in Influenza A (H1N1) Pathogenesis

There is an annual increase of influenza-related SARI cases in winter months. Despite the high relevance of this problem, influenza pathogenesis and the role of surfactant system and its SP-A (surfactant protein A) enzyme in antiviral defense remain poorly understood. SP-A activates macrophage M1 polarization and triggers an antiviral response due to the activation of T-cells and dendritic cells. Therefore, surfactant system is an important element of infection protection and a promising therapeutic target.

Periplaneta americana extract promotes infectious diabetic ulcers wound healing by downregulation of LINC01133/SLAMF9

Wound healing in diabetic ulcers remains a significant clinical challenge,primarily due to bacterial infection and impaired angiogenesis.Periplaneta americana extract(PAE)has been widely used to treat diabetic wounds,yet its underlying mechanisms are not fully understood.This study aimed to elucidate these mechanisms by analyzing long non-coding RNA(lncRNA)expressions in the wound tissues from diabetic anal fistula patients treated with or without PAE,using high-throughput sequencing.Peripheral blood monocytes from patients were differentiated into M0 macrophages with human macrophage colony-stimulating factor(hMCSF)and subsequently polarized into M1 macrophages with lipopolysaccharide.The results indicated that LINC01133 and SLAMF9 were downregulated in wound tissues of patients treated with PAE.Furthermore,PAE suppressed M1 macrophage polarization and enhanced human umbilical vein endothelial cell(HUVEC)proliferation,migration,and angiogenesis.These effects were diminished when LINC01133 or SLAMF9 were overexpressed.Mechanistically,LINC01133 was shown to upregulate SLAMF9 through interaction with ELAVL1.Overexpression of SLAMF9 reversed the effects of LINC01133 silencing on macrophage polarization and HUVEC functions.In conclusion,PAE facilitates the healing of infected diabetic ulcers by downregulating the LINC01133/SLAMF9 pathway.

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.

CIS controls the functional polarization of GM-CSF-derived macrophages

The cytokine granulocyte-macrophage-colony stimulating factor (GM-CSF) possesses the capacity to differentiate monocytes into macrophages (MØs) with opposing functions, namely, proinflammatory M1-like MØs and immunosuppressive M2-like MØs. Despite the importance of these opposing biological outcomes, the intrinsic mechanism that regulates the functional polarization of MØs under GM-CSF signaling remains elusive. Here, we showed that GM-CSF-induced MØ polarization resulted in the expression of cytokine-inducible SH2-containing protein (CIS) and that CIS deficiency skewed the differentiation of monocytes toward immunosuppressive M2-like MØs. CIS deficiency resulted in hyperactivation of the JAK-STAT5 signaling pathway, consequently promoting downregulation of the transcription factor Interferon Regulatory Factor 8 (IRF8). Loss- and gain-of-function approaches highlighted IRF8 as a critical regulator of the M1-like polarization program. In vivo, CIS deficiency induced the differentiation of M2-like macrophages, which promoted strong Th2 immune responses characterized by the development of severe experimental asthma. Collectively, our results reveal a CIS-modulated mechanism that clarifies the opposing actions of GM-CSF in MØ differentiation and uncovers the role of GM-CSF in controlling allergic inflammation.

IGF2BP3 Enhances the Growth of Hepatocellular Carcinoma Tumors by Regulating the Properties of Macrophages and CD8^(+)T Cells in the Tumor Microenvironment

Background and Aims:Overexpression of IGF2BP3 is associated with the prognosis of hepatocellular carcinoma(HCC).However,its role in regulating tumor immune microenvironment(TME)is not well characterized.Here,we investigated the effects of IGF2BP3 on macrophages and CD8^(+)T cells within the TME of HCC.Methods:The relationship between IGF2BP3 and immune cell infiltration was analyzed using online bioinformatics tools.Knockout of IGF2BP3 in mouse hepatoma cell line Hepa1-6 was established using CRISPR/Cas9 technology.In vitro cell coculture and subcutaneously implanted hepatoma mice model were used to explore the effects of IGF2BP3 on immune cells.Expression of CCL50l transforming growth factor beta 1(TGF-β1)was detected with quantitative real-time polymerase chain reaction,western blotting,and enzyme-linked immunosorbent assay.The binding of IGF2BP3 and its target RNA was verified by trimolecular fluorescence complementation system and RNA immunoprecipitation followed by quantitative or semiquantitative polymerase chain reaction.Results:IGF2BP3 expression was elevated in HCC and was positively correlated with macrophage infiltration.Patients with higher IGF2BP3 expression and lower macrophage infiltration had a better survival rate.We found that IGF2BP3 could bind to the mRNA of CCL5 or TGF-β1,increasing their expression,and inducing macrophage infiltration and M2 polarization while inhibiting the activation of CD8^(+)T cells.Furthermore,inhibition of IGF2BP3 combined with anti-CD47 antibody treatment significantly suppressed the growth of hepatoma in Hepa1-6 xenograft tu-mor mice.Conclusions:IGF2BP3 promoted the infiltration and M2-polarization of macrophages and suppressed CD8^(+)T activation by enhancing CCL5 and TGF-β1 expression,which facilitated the progression of Hepa1-6 xenograft tumor.

Proteomic characterization of four subtypes of M2 macrophages derived from human THP-1 cells

Macrophages are widely distributed immune cells that contribute to tissue homeostasis.Human THP-1 cells have been widely used in various macrophage-associated studies,especially those involving pro-inflammatory M1 and anti-inflammatory M2 phenotypes.However,the molecular characterization of four M2 subtypes(M2a,M2b,M2c,and M2d)derived from THP-1has not been fully investigated.In this study,we systematically analyzed the protein expression profiles of human THP-1-derived macrophages(M0,M1,M2a,M2b,M2c,and M2d)using quantitative proteomics approaches.The commonly and specially regulated proteins of the four M2 subtypes and their potential biological functions were further investigated.The results showed that M2a and M2b,and M2c and M2d have very similar protein expression profiles.These data could serve as an important resource for studies of macrophages using THP-1 cells,and provide a reference to distinguish different M2 subtypes in macrophage-associated diseases for subsequent clinical research.