Global trends in publications regarding macrophages-related diabetic foot ulcers in the last two decades

BACKGROUND Diabetic foot ulcers(DFUs)are one of the most severe and popular complications of diabetes.The persistent non-healing of DFUs is the leading cause of amputation,which causes significant mental and financial stress to patients and their families.Macrophages are critical cells in wound healing and perform essential roles in all phases of wound healing.However,no studies have been carried out to systematically illustrate this area from a scientometric point of view.Although there have been some bibliometric studies on diabetes,reports focusing on the investigation of macrophages in DFUs are lacking.AIM To perform a bibliometric analysis to systematically assess the current state of research on macrophage-related DFUs.METHODS The publications of macrophage-related DFUs from January 1,2004,to December 31,2023,were retrieved from the Web of Science Core Collection on January 9,2024.Four different analytical tools:VOSviewer(v1.6.19),CiteSpace(v6.2.R4),HistCite(v12.03.07),and Excel 2021 were used for the scientometric research.RESULTS A total of 330 articles on macrophage-related DFUs were retrieved.The most published countries,institutions,journals,and authors in this field were China,Shanghai Jiao Tong University of China,Wound Repair and Regeneration,and Aristidis Veves.Through the analysis of keyword co-occurrence networks,historical direct citation networks,thematic maps,and trend topics maps,we synthesized the prevailing research hotspots and emerging trends in this field.CONCLUSION Our bibliometric analysis provides a comprehensive overview of macrophage-related DFUs research and insights into promising upcoming research.

Exosomal microRNA-588 from M2 polarized macrophages contributes to cisplatin resistance of gastric cancer cells

BACKGROUND Gastric cancer is a prevalent malignant cancer with a high incidence and significantly affects the health of modern people globally.Cisplatin(DDP)is one of the most common and effective chemotherapies for patients with gastric cancer,but DDP resistance remains a severe clinical challenge.AIM To explore the function of M2 polarized macrophages-derived exosomal microRNA(miR)-588 in the modulation of DDP resistance of gastric cancer cells.METHODS M2 polarized macrophages were isolated and identified by specific markers using flow cytometry analysis.The exosomes from M2 macrophages were identified by transmission electron microscopy and related markers.The uptake of the PKH67-labelled M2 macrophages-derived exosomes was detected in SGC7901 cells.The function and mechanism of exosomal miR-588 from M2 macrophages in the modulation of DDP resistance of gastric cancer cells was analyzed by CCK-8 assay,apoptosis analysis,colony formation assay,Western blot analysis,qPCR analysis,and luciferase reporter assay in SGC7901 and SGC7901/DDP cells,and by tumorigenicity analysis in nude mice.RESULTS M2 polarized macrophages were isolated from mouse bone marrow stimulated with interleukin(IL)-13 and IL-4.Co-cultivation of gastric cancer cells with M2 polarized macrophages promoted DDP resistance.M2 polarized macrophagesderived exosomes could transfer in gastric cancer cells to enhance DDP resistance.Exosomal miR-588 from M2 macrophages contributed to DDP resistance of gastric cancer cells.miR-588 promoted DDP-resistant gastric cancer cell growth in vivo.miR-588 was able to target cylindromatosis(CYLD)in gastric cancer cells.The depletion of CYLD reversed miR-588 inhibition-regulated cell proliferation and apoptosis of gastric cancer cells exposed to DDP.CONCLUSION In conclusion,we uncovered that exosomal miR-588 from M2 macrophages contributes to DDP resistance of gastric cancer cells by partly targeting CYLD.miR-588 may be applied as a potential therapeutic target for the treatment of gastric cancer.

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.

Hydrogel loaded with bone marrow stromal cell-derived exosomes promotes bone regeneration by inhibiting inflammatory responses and angiogenesis

BACKGROUND Bone healing is a complex process involving early inflammatory immune regu-lation,angiogenesis,osteogenic differentiation,and biomineralization.Fracture repair poses challenges for orthopedic surgeons,necessitating the search for efficient healing methods.AIM To investigate the underlying mechanism by which hydrogel-loaded exosomes derived from bone marrow mesenchymal stem cells(BMSCs)facilitate the process of fracture healing.METHODS Hydrogels and loaded BMSC-derived exosome(BMSC-exo)gels were charac-terized to validate their properties.In vitro evaluations were conducted to assess the impact of hydrogels on various stages of the healing process.Hydrogels could recruit macrophages and inhibit inflammatory responses,enhance of human umbilical vein endothelial cell angiogenesis,and promote the osteogenic differen-tiation of primary cranial osteoblasts.Furthermore,the effect of hydrogel on fracture healing was confirmed using a mouse fracture model.RESULTS The hydrogel effectively attenuated the inflammatory response during the initial repair stage and subsequently facilitated vascular migration,promoted the formation of large vessels,and enabled functional vascularization during bone repair.These effects were further validated in fracture models.CONCLUSION We successfully fabricated a hydrogel loaded with BMSC-exo that modulates macrophage polarization and angiogenesis to influence bone regeneration.

FAM53B promotes pancreatic ductal adenocarcinoma metastasis by regulating macrophage M2 polarization

BACKGROUND Our study investigated the role of FAM53B in regulating macrophage M2 polarization and its potential mechanisms in promoting pancreatic ductal adenocarcinoma(PDAC)metastasis.AIM To further investigate the role of FAM53B in regulating macrophage M2 polarization and its potential mechanism in promoting PDAC metastasis.Our goal is to determine how FAM53B affects macrophage M2 polarization and to define its underlying mechanism in PDAC metastasis.METHODS Cell culture and various experiments,including protein analysis,immunohisto-chemistry,and animal model experiments,were conducted.We compared FAM53B expression between PDAC tissues and healthy tissues and assessed the correlation of FAM53B expression with clinical features.Our study analyzed the role of FAM53B in macrophage M2 polarization in vitro by examining the expression of relevant markers.Finally,we used a murine model to study the role of FAM53B in PDAC metastasis and analyzed the potential underlying mechanisms.RESULTS Our research showed that there was a significant increase in FAM53B levels in PDAC tissues,which was linked to adverse tumor features.Experimental findings indicated that FAM53B can enhance macrophage M2 polarization,leading to increased anti-inflammatory factor release.The results from the mouse model further supported the role of FAM53B in PDAC metastasis,as blocking FAM53B prevented tumor cell invasion and metastasis.CONCLUSION FAM53B promotes PDAC metastasis by regulating macrophage M2 polarization.This discovery could lead to the development of new strategies for treating PDAC.For example,interfering with the FAM53B signaling pathway may prevent cancer spread.Our research findings also provide important information for expanding our understanding of PDAC pathogenesis.

The IL-33/ST2 axis affects tumor growth by regulating mitophagy in macrophages and reprogramming their polarization

Objective:Macrophages are a major component of the tumor microenvironment.M1 macrophages secrete pro-inflammatory factors that inhibit tumor growth and development,whereas tumor-associated macrophages(TAMs)mainly exhibit an M2 phenotype.Our previous studies have shown that the interleukin-33/ST2(IL-33/ST2)axis is essential for activation of the M1 phenotype.This study investigates the role of the IL-33/ST2 axis in TAMs,its effects on tumor growth,and whether it participates in the mutual conversion between the M1 and M2 phenotypes.Methods:Bone marrow-derived macrophages were extracted from wildtype,ST2 knockout(ST2-/-),and Il33-overexpressing mice and differentiated with IL-4.The mitochondrial and lysosomal number and location,and the expression of related proteins were used to analyze mitophagy.Oxygen consumption rates and glucose and lactate levels were measured to reveal metabolic changes.Results:The IL-33/ST2 axis was demonstrated to play an important role in the metabolic conversion of macrophages from OXPHOS to glycolysis by altering mitophagy levels.The IL-33/ST2 axis promoted enhanced cell oxidative phosphorylation,thereby further increasing M2 polarization gene expression and ultimately promoting tumor growth(P<0.05)(Figure 4).This metabolic shift was not due to mitochondrial damage,because the mitochondrial membrane potential was not significantly altered by IL-4 stimulation or ST2 knockout;however,it might be associated with the m TOR activity.Conclusions:These results clarify the interaction between the IL-33/ST2 pathway and macrophage polarization,and may pave the way to the development of new cancer immunotherapies targeting the IL-33/ST2 axis.

Effect of clearing heat and detoxification method on macrophages polarization in patients with acute myocardial infarction and heat toxin syndrome after intervention

Objective:To evaluate the effect of heat-clearing and detoxifying method on the macrophages polarization in patients with acute myocardial infarction with heat toxin syndrome after intervention.Methods:Sixty patients with acute myocardial infarction and undergoing percutaneous coronary intervention with heat toxin syndrome were randomly divided into a control group and a test group with 30 cases each.The control group was given conventional treatment,and the test group was given Huanglian Jiedu Decoction,the representative of the method of clearing heat and detoxification,orally on the basis of the control group.The intervention time of both groups was 2 weeks.Comparing The Seattle Angina Pectoris Scale(SAQ)before and after treatment,creatine kinase(CK),creatine kinase MB isoenzyme(CKMB),high-sensitivity troponin I(hs-TnI),and Lipoprotein-associated phospholipaseA2(LPPLA_2)),the phenotype ratio of M1 and M2 macrophages,and observe the adverse reactions.Results:After treatment,the SAQ scores of the two groups of patients were improved,and the levels of CK,CK-MB,hs-TnI,and LP-PLA_2 decreased significantly.The scores of AS,AF,TS,and DP in the SAQ of the test group were all higher than those of the control group,and the hs-TnI and LP-PLA_2 were better than those of the control Group(P<0.05 or P<0.01).After treatment,the proportion of M1 type macrophages in the two groups of patients'macrophages decreased significantly(P<0.05 or P<0.01),the ratio of M2 type macrophages increased(P<0.05),and the M1/M2 ratio decreased.The ratio of M1/M2 in the test group of the control group was significantly lower than that of the control group(P<0.01).There were no obvious adverse reactions in both groups.Conclusions:The method of clearing heat and detoxifying has a definite effect on patients with acute myocardial infarction of heat toxin syndrome after interventional operation.It can reduce myocardial damage,improve myocardial function,and reduce inflammation.And it is safe for clinical treatment without any increasing risk of bleeding or other risk of cardiovascular events.

Effect of Pingchuan granule on typeⅡinnate lymphocytes and M2 polarization of macrophages in asthmatic mice

Objective:To observe the effect of Pingchuan granule on the number of typeⅡinnate lymphocytes(ILC2)and M2 polarization of macrophages in the lung tissue of asthmatic mice;Methods:Ovalbumin sensitized and challenged asthmatic mouse models were established,and then Pingchuan granules or IL-33 neutralizing antibody were given to intervene.The pathological morphology of lung tissue was observed by HE,PAS and Masson staining,and the expressions of IL-4,IL-5,IL-13 and IL-33 in BALF and lung tissue were detected by ELISA and qRT-PCR,Flow cytometry was used to detect the number of type II innate lymphocytes and type M2 macrophages in lung tissue.Western blot was used to detect the protein expression levels of ST-2,FIZZ1 and Arg-1 in lung tissue;Results:Compared with the control group,the inflammation score,PAS score and collagen staining area of the model group were significantly increased,the expressions of IL-4,IL-5,IL-13 and IL-33 in BALF and lung tissue were significantly increased,the number of ILC2 and M2 macrophages,the expression of ST-2,FIZZ1 and Arg-1 protein in lung tissue were significantly increased,and the differences were statistically significant(P<0.05);Compared with the model group,Pingchuan granule could significantly reduce the inflammation score,PAS score and collagen staining area of asthmatic mice,down-regulate the expression of IL-4,IL-5,IL-13 and IL-33 in BALF and lung tissue,reduce the number of ILC2 and M2 macrophages,and the expression of ST-2,FIZZ1 and Arg-1 protein in lung tissue(P<0.05);Conclusion:Pingchuan granule improve the airway remodeling of asthma by inhibiting the polarization of M2 macrophages mediated by ILC2.

Atorvastatin ameliorated myocardial fibrosis in db/db mice by inhibiting oxidative stress and modulating macrophage polarization

BACKGROUND People with diabetes mellitus(DM)suffer from multiple chronic complications due to sustained hyperglycemia,especially diabetic cardiomyopathy(DCM).Oxidative stress and inflammatory cells play crucial roles in the occurrence and progression of myocardial remodeling.Macrophages polarize to two distinct phenotypes:M1 and M2,and such plasticity in phenotypes provide macrophages various biological functions.AIM To investigate the effect of atorvastatin on cardiac function of DCM in db/db mice and its underlying mechanisms.METHODS DCM mouse models were established and randomly divided into DM,atorvastatin,and metformin groups.C57BL/6 mice were used as the control.Cardiac function was evaluated by echocardiography.Hematoxylin and eosin and Masson staining was used to examine the morphology and collagen fibers in myocardial tissues.The expression of transforming growth factor-β1(TGF-β1),tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),M1 macrophages(iNOS^(+)),and M2 macrophages(CD206^(+))were demonstrated by immunohistochemistry and immunofluorescence staining.The levels of TGF-β1,IL-1β,and TNF-αwere detected by ELISA and real-time quantitative polymerase chain reaction.Malondialdehyde(MDA)concentrations and superoxide dismutase(SOD)activities were also measured.RESULTS Treatment with atorvastatin alleviated cardiac dysfunction and decreased db/db mice. The broken myocardialfibers and deposition of collagen in the myocardial interstitium were relieved especially by atorvastatin treatment.Atorvastatin also reduced the levels of serum lactate dehydrogenase, creatine kinase isoenzyme, and troponin;lowered the levels of TGF-β1, TNF-α and IL-1β in serum and myocardium;decreased the concentration of MDAand increased SOD activity in myocardium of db/db mice;inhibited M1 macrophages;and promoted M2macrophages.CONCLUSION Administration of atorvastatin attenuates myocardial fibrosis in db/db mice, which may be associated with theantioxidative stress and anti-inflammatory effects of atorvastatin on diabetic myocardium through modulatingmacrophage polarization.

Application of mannose-modified fullerene immunomodulator selectively polarizes tumor-associated macrophages potentiating antitumor immunity

Polarization of tumor associated macrophages(TAMs)has been a promising therapeutic paradigm for tumor.However,how to achieve precise regulation of TAMs and high efficiency of tumor immunotherapy is still a huge challenge.Here,we report dicarboxy fullerene modified with mannose(DCFM)as an immunomodulator to selectively polarize TAMs and prominently boost anti-tumor immunity.The dicarboxy fullerene molecule was synthesized through the Prato reaction and further covalently bonded with mannose,obtaining the DCFM with well-defined structure.Due to the exist of mannose in DCFM,it could accurately recognize mannose receptor in TAMs.Our cellular experiment results showed that mannose modification could notably promote the uptake of DCFM by the immunosuppressive M2-type macrophages that effectively reprogrammed M2-type macrophages into anti-tumor M1-type macrophages,leading to enhance the phagocytosis of tumor cells by macrophages and inhibiting tumor cells migration.Subsequently,we observed that DCFM could significantly distribute into tumor tissues by in vivo fluorescence imaging.Importantly,DCFM exhibited a superior anti-tumor efficiency in the subcutaneous colorectal tumor model.In addition,it showed that DCFM precisely polarized TAMs into M1-type macrophages and actively increased the infiltration of cytotoxic T lymphocytes(CTLs),inducing profound tumor growth inhibition.

Macrophage involvement in the pathological evolution of ulcerative colitis-associated colon cancer and progress of related traditional Chinese medicine drug interventions

Intestinal macrophages are essential players in intestinal inflammation and intestinal immune homeostasis.Intestinal macrophages have the ability to polarize into two distinct phenotypes based on various environmental signals.These phenotypes include the typically activated pro-inflammatory M1 phenotype and the alternatively activated anti-inflammatory M2 phenotype.Under normal circumstances,intestinal macrophages prevent inflammatory damage to the gut.However,when genetic and environmental factors influence the polarization of intestinal macrophages,it can lead to an imbalance in M1/M2 macrophage activation and subsequently an imbalance in the control of intestinal inflammation.It transforms physiological inflammation into pathological intestinal damage.In patients with ulcerative colitis-associated cancer(UC-CRC),intestinal inflammatory disorders are closely associated with intestinal M1/M2 macrophage polarization imbalance.Consequently,restoring the polarization equilibrium of M1/M2 macrophages might be an evidence of traditional Chinese medicine in the treatment of UC-CRC,the pivotal role o effective measure to prevent and treat UC-CRC.This paper aims to examine the clinicalf macrophage polarization in UC-CRC pathogenesis,and the potential mechanisms of traditional Chinese medicine in regulating macrophage polarization to treat UC-CRC.Our goal is to provide novel insights into the clinical practice,basic research,and drug development of UC-CRC.

Exploration of the molecular mechanism of Qishen decoction in regulating miR-495/FTO pathway mediated macrophage polarization to improve insulin resistance therapy of type 2 diabetes

Objective:To observe the effect of Qishen decoction on macrophage polarization mediated by miR-495/FTO signaling pathway,and to clarify the molecular mechanism of Qishen decoction in improving insulin resistance in the treatment of type 2 diabetes.Methods:THP-1 was induced to differentiate macrophages with phorbol ester.It was divided into the control group,the model group,the Qishen decoction group,the miR-495 inhibitor group,and the Qishen decoction+miR-495 inhibitor group.Except for the control group,the remaining groups were stimulated with 30 mmol/L glucose to construct a macrophage polarization model,and corresponding drugs were given for intervention.Cells were collected from each group for 24 hours and the content of inflammatory factors(IL-6,IL-1β,IL-4,and IL-10)were detected using enzyme-linked immunosorbent assay.The expression of macrophage polarization marker molecules,miR-495,and FTO were detected by flow cytometry,qPCR,and Western blot to detect.Results:Compared with the control group,there was no significant change in the activity of macrophages in the control serum,Qishen decoction containing serum,and miR-495 inhibitor transfected serum,and the difference was not statistically significant(P>0.05).In addition,compared to the control group,the content of IL-6 and IL-1β,the expression levels of CD68,iNOS,COX-2,miR-495,and the ratio of CD68/CD206,were significantly increased(P<0.01).While the content of IL-4 and IL-10,as well as the expression of CD206,Arg-1,YM-1,and FTO were significantly reduced(P<0.01).Compared with the model group,the QiShen decoction significantly reduced the contents of IL-6 and IL-1β,and the expression levels of CD68,iNOS,COX-2,and miR-495,as well as the ratio of CD68/CD206,while the content of IL-4 and IL-10,as well as the expression of CD206,Arg-1,YM-1,and FTO were significantly increased(P<0.01).Conclusion:Qishen decoction upregulate the expression of FTO to promote M2 type polarization of macrophages,thereby inhibiting inflammation and improving insulin resistance by inhibiting the expression of miR-495.

The mechanism of regulating macrophage polarization based on Notch1 signaling pathway to improve joint inflammation in adjuvant arthritis rats

Objective:To study the impact of the Notch1/Jagged1/RBP-Jκ/Hes1 signaling pathway on macrophage polarization and its role in modulating the inflammatory response in rats with adjuvant arthritis(AA).Methods:The rats were randomly divided into three groups(6 rats):the healthy group(NC),the model group(MC),and the Notch1 inhibitor group(FLI).Medication was administered after 12 days of inducing inflammation.After 30 days,the arthritis index(AI)and degree of swelling in the right hind foot joint(E)were measured in each group.The expression levels of CD80^(+)and CD163^(+)cells in peripheral blood macrophages of rats were analyzed by flow cytometry.The standards of IL-4,IL-10,IL-1β,and TNF-α in rat serum were gauged by Enzyme-linked immunosorbent assay.The expression of Notch1,Jagged1,RBP-Jκ,and Hes1 proteins in rat synovial tissue was detected using Western blot.Results:The degree of swelling(E)and arthritis index(AI)in the MC group rats with AA were significantly higher than those in the NC group(P<0.01).CD80^(+)cell expression was significantly higher compared to the control group(P<0.01),while CD163^(+)cell expression was significantly lower than the control group(P<0.01).IL-1βand TNF-α expression levels were significantly elevated(P<0.01),whereas IL-4 and IL-10 expression levels were significantly decreased(P<0.01).Notch1,RBP-Jκ,Jagged1,and Hes1 protein expression levels were significantly increased(P<0.01).In comparison to the MC group,the rats in the Notch1 inhibitor group exhibited a significant reduction in toe swelling and arthritis index(P<0.01).CD80^(+)cell expression was significantly decreased(P<0.01),while CD163+cell expression was significantly increased(P<0.01).IL-1β and TNF-α expression levels were significantly decreased(P<0.05),whereas IL-4 and IL-10 levels were significantly increased(P<0.01).Notch1,Jagged1,Hes1,and RBP-Jκ protein expression levels were significantly decreased(P<0.05).Correlation analysis revealed a positive association between CD80^(+)and Notch1,Jagged1,Hes1,and RBP-Jκ(P<0.01),while CD163^(+)showed a negative correlation with the expression of these proteins(P<0.01).Conclusion:The Notch1/Jagged1/RBP-Jκ/Hes1 signaling axis regulates macrophage polarization to M2 type and reduces inflammation in AA rats.

Xiaochaihu decoction alleviates viral pneumonia by regulating macrophage polarization

Background:In this investigation,we sought to evaluate the benefits of Xiaochaihu decoction(XCHD)on polyinosinic:polycytidylic acid-induced viral pneumonia in mice and elucidate its mechanisms of action.Method:A viral pneumonia model was established in mice using polyinosinic:polycytidylic acid,with mice being intragastrically administered different doses of XCHD.The benefits of XCHD therapy for mice with viral pneumonia were assessed by determining the weight ratio of lung tissue,wet-to-dry,overall protein concentrations,and total cell counts in bronchoalveolar lavage fluid,and hematoxylin and eosin staining of lung tissues.By determining the interleukin-1βlevels,interleukin-6,tumor necrosis factor-alpha,nitric oxide,interleukin-10,and interleukin-4,and the mRNA and protein expression of nitric oxide synthase 2,arginase-1,and macrophage mannose receptor 1 in bronchoalveolar lavage fluid,we assessed consequences of XCHD on macrophage polarization with mice suffering from viral pneumonia.Results:XCHD was found to significantly reduce lung tissue wet-to-dry and the total protein content and total number of cells of bronchoalveolar lavage fluid,while ameliorating pathological modifications to the lung tissues of rodents suffering from viral pneumonia,thereby indicating that this medicinal preparation has a healing impact on model mice with viral pneumonia.In addition,XCHD was found to reduce the magnitudes of interleukin-1β,interleukin-6,tumor necrosis factor-alpha,and nitric oxide and the mRNA and protein manifestation of nitric oxide synthase 2,and promote an increase in the levels of interleukin-10 and interleukin-4 and the mRNA and protein expression of arginase-1 and macrophage mannose receptor 1,thereby indicating that XCHD can favorably mediate polarization of macrophages in mice with viral pneumonia.Conclusion:XCHD has notable therapeutic effects on viral pneumonia in mice,the fundamental workings of action of which may be connected to regulation of macrophage polarization.

Response gene to complement 32 （RGC-32） expression on M2-polarized and tumor-associated macrophages is M-CSF-dependent and enhanced by tumor-derived IL-4

Response gene to complement 32 （RGC-32） is a cell cycle regulator involved in the proliferation, differentiation and migration of cells and has also been implicated in angiogenesis. Here we show that RGC-32 expression in macrophages is induced by IL-4 and reduced by LPS, indicating a link between RGC-32 expression and M2 polarization. We demonstrated that the increased expression of RGC-32 is characteristic of alternatively activated macrophages, in which this protein suppresses the production of pro-inflammatory cytokine IL-6 and promotes the production of the anti-inflammatory mediator TGF-β. Consistent with in vitro data, tumor-associated macrophages （TAMs） express high levels of RGC-32, and this expression is induced by tumor-derived ascitic fluid in an M-CSF- and/or IL-4-dependent manner. Collectively, these results establish RGC-32 as a marker for M2 macrophage polarization and indicate that this protein is a potential target for cancer immunotherapy, targeting tumor-associated macrophages.

Bone marrow mesenchymal stem cells induce M2 microglia polarization through PDGF-AA/MANF signaling

BACKGROUND Bone marrow mesenchymal stem cells(BMSCs)are capable of shifting the microglia/macrophages phenotype from M1 to M2,contributing to BMSCsinduced brain repair.However,the regulatory mechanism of BMSCs on microglia/macrophages after ischemic stroke is unclear.Recent evidence suggests that mesencephalic astrocyte-derived neurotrophic factor(MANF)and plateletderived growth factor-AA(PDGF-AA)/MANF signaling regulate M1/M2 macrophage polarization.AIM To investigate whether and how MANF or PDGF-AA/MANF signaling influences BMSCs-mediated M2 polarization.METHODS We identified the secretion of MANF by BMSCs and developed transgenic BMSCs using a targeting small interfering RNA for knockdown of MANF expression.Using a rat middle cerebral artery occlusion(MCAO)model transplanted by BMSCs and BMSCs-microglia Transwell coculture system,the effect of BMSCsinduced downregulation of MANF expression on the phenotype of microglia/macrophages was tested by Western blot,quantitative reverse transcription-polymerase chain reaction,and immunofluorescence.Additionally,microglia were transfected with mimics of miR-30a*,which inuenced expression of X-box binding protein(XBP)1,a key transcription factor that synergized with activating transcription factor 6(ATF6)to govern MANF expression.We examined the levels of miR-30a*,ATF6,XBP1,and MANF after PDGF-AA treatment in the activated microglia.RESULTS Inhibition of MANF attenuated BMSCs-induced functional recovery and decreased M2 marker production,but increased M1 marker expression in vivo or in vitro.Furthermore,PDGF-AA treatment decreased miR-30a*expression,had no influence on the levels of ATF6,but enhanced expression of both XBP1 and MANF.CONCLUSION BMSCs-mediated MANF paracrine signaling,in particular the PDGF-AA/miR-30a*/XBP1/MANF pathway,synergistically mediates BMSCs-induced M2 polarization.

C-C chemokine receptor type 2-overexpressing exosomes alleviated experimental post-stroke cognitive impairment by enhancing microglia/macrophage M2 polarization

BACKGROUND Human-derived mesenchymal stromal cells have been shown to improve cognitive function following experimental stroke.The activity of exosomes has been verified to be comparable to the therapeutic effects of mesenchymal stromal cells.However,the effects of exosomes derived from human umbilical cord mesenchymal stem cells(HUC-MSCs)(ExoCtrl)on post-stroke cognitive impairment(PSCI)have rarely been reported.Moreover,whether exosomes derived from C-C chemokine receptor type 2(CCR2)-overexpressing HUC-MSCs(ExoCCR2)can enhance the therapeutic effects on PSCI and the possible underlying mechanisms have not been studied.AIM To investigate the effects of ExoCtrl on PSCI and whether ExoCCR2 can enhance therapeutic effects on PSCI.METHODS Transmission electron microscopy,qNano®particles analyzer,and Western blotting were employed to determine the morphology and CCR2 expression of ExoCtrl or ExoCCR2.ELISA was used to study the binding capacity of exosomes to CC chemokine ligand 2(CCL2)in vivo.After the intravenous injection of ExoCtrl or ExoCCR2 into experimental rats,the effect of ExoCtrl and ExoCCR2 on PSCI was assessed by Morris water maze.Remyelination and oligodendrogenesis were analyzed by Western blotting and immunofluorescence microscopy.QRT-PCR and immunofluorescence microscopy were conducted to compare the microglia/macrophage polarization.The infiltration and activation of hematogenous macrophages were analyzed by Western blotting and transwell migration analysis.RESULTS CCR2-overexpressing HUC-MSCs loaded the CCR2 receptor into their exosomes.The morphology and diameter distribution between ExoCtrl and ExoCCR2 showed no significant difference.ExoCCR2 bound significantly to CCL2 but ExoCtrl showed little CCL2 binding.Although both ExoCCR2 and ExoCtrl showed beneficial effects on PSCI,oligodendrogenesis,remyelination,and microglia/macrophage polarization,ExoCCR2 exhibited a significantly superior beneficial effect.We also found that ExoCCR2 could suppress the CCL2-induced macrophage migration and activation in vivo and in vitro,compared with ExoCtrl treated group.CONCLUSION CCR2 over-expression enhanced the therapeutic effects of exosomes on the experimental PSCI by promoting M2 microglia/macrophage polarization,enhancing oligodendrogenesis and remyelination.These therapeutic effects are likely through suppressing the CCL2-induced hematogenous macrophage migration and activation.Key words:Cognitive impairment;Stroke;Exosomes;C-C chemokine receptor type 2;Microglia/macrophage polarization;Remyelination.

Macrophage membrane-mediated targeted drug delivery for treatment of spinal cord injury regardless of the macrophage polarization states

Targeted delivery of therapeutics for spinal cord injury(SCI)has been a long-term challenge due to the complexity of the pathological procession.Macrophage,as an immune cell,can selectively accumulate at the trauma site after SCI.This intrinsic targeting,coupled with good immune-escaping capacity makes macrophages an ideal source of biomimetic delivery carrier for SCI.Worth mentioning,macrophages have multiple polarization states,which may not be ignored when designing macrophage-based delivery systems.Herein,we fabricated macrophage membrane-camouflaged liposomes(RM-LIPs)and evaluated their abilities to extend drug circulation time and target the injured spinal cord.Specially,we detected the expression levels of the two main targeted receptors Mac-1 and integrinα4 in three macrophage subtypes,including unactivated(M0)macrophages,classically activated(M1)macrophages and alternatively activated(M2)macrophages,and compared targeting of these macrophage membrane-coated nanoparticles for SCI.The macrophage membrane camouflage decreased cellular uptake of liposomes in RAW264.7 immune cells and strengthened binding of the nanoparticle to the damaged endothelial cells in vitro.RM-LIPs can prolong drug circulation time and actively accumulate at the trauma site of the spinal cord in vivo.Besides,RM-LIPs loaded with minocycline(RM-LIP/MC)showed a comprehensive therapeutic effect on SCI mice,and the anti-pyroptosis was found to be a novel mechanism of RM-LIP/MC treatment of SCI.Moreover,the levels of Mac-1 and integrinα4 in macrophages and the targeting of RM-LIP for SCI were found to be independent of macrophage polarization states.Our study provided a biomimetic strategy via the biological properties of macrophages for SCI targeting and treatment.

BET protein inhibitor apabetalone represses Porphyromonas gingivalis LPS-induced macrophage M1 polarization via regulating miR-130a/STAT3 axis

Periodontitis is a frequent chronic inflammatory disorder destroying periodontium.Recent studies have revealed the role of bromodomain and extraterminal domain inhibitor(BETi)and microRNA(miR)-130a in regulating macrophage polarization and pro-inflammatory response.However,little is known about whether apabetalone(a novel BETi)and miR-130a are correlated with chronic inflammatory state in periodontitis by regulating macrophage polarization.Here murine RAW264.7 macrophages were applied as an in vitro inflammatory model.After treatment with Porphyromonas gingivalis-derived lipopolysaccharide(Pg LPS)and apabetalone,the expression of macrophage M1 polarization markers and inflammatory cytokines was assessed using real-time PCR,western blot,and enzyme-linked immuno sorbent assay(ELISA).MiR-130a level was assessed using real-time PCR,and the target gene was identified using dual luciferase reporter assay.We demonstrated that apabetalone repressed Pg LPS-induced macrophage M1 polarization in a dose-dependent manner,as evidenced by decreased expression of inducible nitric oxide synthase(iNOS),CD86,and pro-inflammatory cytokines,and increased expression of Arg-1 and CD206.Mechanistically,Pg LPS increased miR-130a expression in macrophages,whereas apabetalone treatment repressed the effect.Functionally,forced expression of miR-130a promoted macrophage M1 polarization,and signal transducer and activator of transcription(STAT)-3 was the direct target gene of miR-130a in the process.Taken together,apabetalone decreases Pg LPS-induced macrophage M1 polarization via regulating miR-130a-3p/STAT3 axis,and may be a promising target for the clinical management of periodontitis.

Macrophage polarization in nerve injury： do Schwann cells play a role？

In response to peripheral nerve injury, the inflammatory response is almost entirely comprised of infiltrating macrophages. Macrophages are a highly plastic, heterogenic immune cell, playing an indispensable role in peripheral nerve injury, clearing debris and regulating the microenvironment to allow for efficient regeneration. There are several cells within the microenvironment that likely interact with macrophages to support their function – most notably the Schwann cell, the glial cell of the peripheral nervous system. Schwann cells express several ligands that are known to interact with receptors expressed by macrophages, yet the effects of Schwann cells in regulating macrophage phenotype remains largely unexplored. This review discusses macrophages in peripheral nerve injury and how Schwann cells may regulate their behavior.