Macrophage Polarization In Mice Research Articles

Retracted: Macrophage Rmp Ameliorates Myocardial Infarction by Modulating Macrophage Polarization in Mice.

[This retracts the article DOI: 10.1155/2022/6248779.].

Irisin modulates bone marrow derived macrophage polarization towards M2 profile in high fat fed mice

Background and Aims: The chronic inflammatory process in the adipose tissue during obesity suggests constant polarization of classically activated macrophages (M1) and low polarization of alternately activated ones (M2). Since irisin has anti-inflammatory and antidiabetogenic properties our aim is to evaluate its effects on macrophage polarization in mice subjected to high fat diet. Methods and Results: C57Bl/6 mice were fed a high fat diet for 30 weeks. Bone marrow derived macrophages (BMDM) were isolated and incubated with 50 nM of irisin. Cellular phenotype, nitrite production, arginase-1 expression and cell viability were analyzed. Irisin was able to increase F480+CD206+ and F480+CD301+ cell number, and arginase1 expression. Irisin was not able to induce nitrite production and did not affect cell viability. Conclusion: Irisin was able to elicit an M2-like profile in macrophages in mice subjected to high fat diet, suggesting an anti-inflammatory action of this cytokine with potential therapeutic use in the control of imflammation during obesity.

Mesenchymal Stromal Cells Regulate M1/M2 Macrophage Polarization in Mice with Immune Thrombocytopenia.

Mesenchymal stromal cells have shown promising effects in the treatment of immune thrombocytopenia. However, the underlying mechanisms are not fully understood. In this study, we investigated the therapeutic effects of human bone marrow mesenchymal stromal cells (hBMSCs) and analyzed their unique role in regulating the M1/M2 macrophage ratio. We established a passive immune thrombocytopenia (ITP) mouse model and showed that there was a significant M1/M2 imbalance in ITP model mice by assessing the M1/M2 ratios in the liver, spleen, and bone marrow; we observed excessive activation of M1 cells and decreased M2 cell numbers in vivo. We have shown that systemic infusion of hBMSCs effectively elevated platelet levels after disease onset. Further analysis revealed that hBMSCs treatment significantly suppressed the number of proinflammatory M1 macrophages and enhanced the number of anti-inflammatory M2 macrophages; in addition, the levels of proinflammatory factors, such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), were significantly decreased in vivo, while the levels of the anti-inflammatory factor interleukin-10 (IL-10) were increased. In conclusion, our data suggest that hBMSCs treatment can effectively increase platelet counts, and the mechanism is related to the induction of macrophage polarization toward the anti-inflammatory M2 phenotype and the decrease in proinflammatory cytokine production, which together ameliorate innate immune disorders.

Surface immobilized α-1 acid glycoprotein and collagen VI modulate mouse macrophage polarization and reduce the foreign body capsule.

Macrophages are widely recognized in modulating the foreign body response, and the manner in which they do so largely depends on their activation state, often referred to as their polarization. This preliminary study demonstrates that surface immobilized α-1 acid glycoprotein (AGP), as well as collagen VI (Col6) in conjunction with AGP, can direct macrophages towards the M2 polarization state in vitro and modify the foreign body response in vivo. AGP and Col6 are immobilized onto poly(2-hydroxyethyl methacrylate) (pHEMA) surfaces using carbonyl diimidazole chemistry. Mouse bone marrow derived macrophages are cultured on modified surfaces with or without lipopolysaccharide stimulation. Surface modified pHEMA discs are implanted subcutaneously into mice to observe differences in the foreign body response. After stimulation with lipopolysaccharide, macrophages cultured on AGP or Col6 modified surfaces showed a reduction in TNF-α expression compared to controls. Arg1 expression was also increased in macrophages cultured on modified surfaces. Explanted tissues showed that the foreign body capsule around implants with AGP or AGP and Col6 modification had reduced thickness, while also being more highly vascularized. These data demonstrate that α-1 acid glycoprotein and collagen VI could potentially be used for the surface modification of medical devices to influence macrophage polarization leading to a reduced and modulated foreign body response.

Excretory/secretory products from Trichinella spiralis adult worms ameliorate myocardial infarction by inducing M2 macrophage polarization in a mouse model

BackgroundIschemia-induced inflammatory response is the main pathological mechanism of myocardial infarction (MI)-caused heart tissue injury. It has been known that helminths and worm-derived proteins are capable of modulating host immune response to suppress excessive inflammation as a survival strategy. Excretory/secretory products from Trichinella spiralis adult worms (Ts-AES) have been shown to ameliorate inflammation-related diseases. In this study, Ts-AES were used to treat mice with MI to determine its therapeutic effect on reducing MI-induced heart inflammation and the immunological mechanism involved in the treatment.MethodsThe MI model was established by the ligation of the left anterior descending coronary artery, followed by the treatment of Ts-AES by intraperitoneal injection. The therapeutic effect of Ts-AES on MI was evaluated by measuring the heart/body weight ratio, cardiac systolic and diastolic functions, histopathological change in affected heart tissue and observing the 28-day survival rate. The effect of Ts-AES on mouse macrophage polarization was determined by stimulating mouse bone marrow macrophages in vitro with Ts-AES, and the macrophage phenotype was determined by flow cytometry. The protective effect of Ts-AES-regulated macrophage polarization on hypoxic cardiomyocytes was determined by in vitro co-culturing Ts-AES-induced mouse bone marrow macrophages with hypoxic cardiomyocytes and cardiomyocyte apoptosis determined by flow cytometry.ResultsWe observed that treatment with Ts-AES significantly improved cardiac function and ventricular remodeling, reduced pathological damage and mortality in mice with MI, associated with decreased pro-inflammatory cytokine levels, increased regulatory cytokine expression and promoted macrophage polarization from M1 to M2 type in MI mice. Ts-AES-induced M2 macrophage polarization also reduced apoptosis of hypoxic cardiomyocytes in vitro.ConclusionsOur results demonstrate that Ts-AES ameliorates MI in mice by promoting the polarization of macrophages toward the M2 type. Ts-AES is a potential pharmaceutical agent for the treatment of MI and other inflammation-related diseases.Graphical

Histone methyltransferase SETD2 inhibits M1 macrophage polarization and glycolysis by suppressing HIF-1α in sepsis-induced acute lung injury.

Sepsis is a severe syndrome caused by the imbalance of the host response to infection, accompanied by multiple organ damage, especially acute lung injury. SET Domain-Containing 2 (SETD2) is a methyltransferase catalyzing H3 lysine 36 trimethylation (H3K36me3) that regulates multiple biological processes. This study focused on explicating the action of SETD2 on macrophage function in sepsis and the precise mechanism involved. Enzyme-linked immunosorbent assay, real-time quantitative polymerase chain reaction (RT-qPCR), and Western blotting were used to determine expression. Luciferase reporter assay and chromatin immunoprecipitation assay were conducted to detect the binding of SETD2 or H3K36me3 with the hypoxia-inducible factor 1, alpha subunit (Hif1a) gene. A sepsis-induced acute lung injury model was constructed via cecal ligation and puncture (CLP). SETD2 was decreased in RAW 264.7 cells stimulated by lipopolysaccharide (LPS). Besides, SETD2 suppressed M1 macrophage polarization and glycolysis caused by LPS. HIF-1α was enhanced in RAW 264.7 cells stimulated by LPS and inversely related to SETD2 expression. In addition, SETD2-catalyzed H3K36me3 bound to the Hif1a gene to modulate HIF-1α expression. Furthermore, Hif1a silencing suppressed Setd2 silencing-induced M1 macrophage polarization and glycolysis in RAW 264.7 cells. Moreover, overexpression of Setd2 inhibited CLP-induced lung injury and M1 macrophage polarization in mice. SETD2 suppressed M1 macrophage polarization and glycolysis via regulating HIF-1α through catalyzing H3K36me3 in sepsis.

The Role of Hyperthermia in Potentiation of Anti-Angiogenic Effect of Cisplatin and Resveratrol in Mice Bearing Solid Form of Ehrlich Ascites Tumour

The aim of this study was to investigate the therapeutic potential of resveratrol in combination with cisplatin on the inhibition of tumour angiogenesis, growth, and macrophage polarization in mice bearing the solid form of an Ehrlich ascites tumour (EAT) that were exposed to whole-body hyperthermia treatment. In addition, we investigated whether a multimodal approach with hyperthermia and resveratrol could abolish cisplatin resistance in tumour cells through the modulation of histone deacetylase (HDAC) activity and levels of heat shock proteins (HSP70/HSP90) and contribute to the direct toxicity of cisplatin on tumour cells. The tumour was induced by injecting 1 × 106 EAT cells subcutaneously (sc) into the thighs of Balb/c mice. The mice were treated with resveratrol per os for five consecutive days beginning on day 2 after tumour injection and/or by injecting cisplatin intraperitoneally (ip) at a dose of 2.5 mg/kg on days 10 and 12 and at a dose of 5 mg/kg on day 15. Immediately thereafter, the mice were exposed to systemic hyperthermia for 15 min at a temperature of 41 °C. The obtained results showed that the administration of resveratrol did not significantly contribute to the antitumour effect of cisplatin and hyperthermia, but it partially contributed to the immunomodulatory effect and to the reduction of cisplatin toxicity and to a slight increase in animal survival. This treatment schedule did not affect microvessel density, but it inhibited tumour growth and modulated macrophage polarization to the M1 phenotype. Furthermore, it abolished the resistance of tumour cells to cisplatin by modulating HDAC activity and the concentration of HSP70 and HSP90 chaperones, contributing to the increased lifespan of mice. However, the precise mechanism of the interaction between resveratrol, cisplatin, and hyperthermia needs to be investigated further.

Vorinostat decrease M2 macrophage polarization through ARID1A6488delG/HDAC6/IL-10 signaling pathway in endometriosis-associated ovarian carcinoma

Endometriosis is a common disease in women and may be one of the factors that induces malignant epithelial ovarian tumors. Previous studies suggested that endometriosis is related to ARID1A mutation mediating the expression of HDAC6, but the detailed pathogenic mechanism is still unclear. First, we collected endometriosis-associated ovarian carcinoma (EAOC) clinical samples and examined the expression of HDAC6. Our results found that the high HDAC6 expression group was positively correlated with EAOC histology (P = 0.015), stage (P < 0.000), and tumor size (P < 0.000) and inversely correlated with survival (P < 0.000). We also found that ARID1A6488delG/HDAC6 induced M2 polarization of macrophages through IL-10. In addition, the HDAC inhibitor (HDACi) vorinostat inhibited cell growth and blocked the effect of HDAC6. Tomographic microscopy was used to monitor the live cell morphology of these treated cells, and we found that vorinostat treatment resulted in substantial cell apoptosis by 3 h 42 min. Next, we established a transgenic mouse model of EAOC and found that vorinostat significantly reduced the size of ovarian tumors by inhibiting M2 macrophage polarization in mice. Together, these data demonstrate that the signaling pathway of E4F1/ARID1A6488delG/HDAC6/GATA3 mediates macrophage polarization and provides a novel immune cell-associated therapeutic strategy targeting IL-10 in EAOC.

Acid external and internal environment exchange the Oreochromis niloticus tissue immune gene expression compared to the mouse macrophage polarization model.

The water environment plays an important role in animal physiology. In this study, we sought to evaluate the effect of the acid environment on the Oreochromis niloticus (Nile tilapia) internal microenvironment immune response compare to the mouse macrophage model (J77A.1). The acid environment treated mouse macrophage J774A.1 model have shown that acidic treatment is able to polarize macrophages into M2-like macrophages via an increase in Ym1, Tgm2, Arg1, Fizz1, and IL-10 expression. Metabolic analysis of mouse macrophages (J774A.1) at pH 2 vs. pH 7 and pH 4 vs. pH 7 have been shown to promote the expression of intracellular acetylcholine, choline, prochlorperazine, L-leucine, and bisphenol A,2-amino-3-methylimidazo[4,5-f] quinolone metabolites in the M2-like macrophage. Immune gene expression of the O. niloticus spleen and liver treated at pH 2, 4, and 7 was shown to reduce TNF-α, IL-1 β, IL-8, and IL-12 expression compared to pH 7 treatment. Immune gene was induced in O. niloticus following culture at pH 5, 6, and 7 fresh water environment. Taken together, we found that the acid internal environment polarizes tissues into an M2 macrophage developmental microenvironment. However, if the external environment is acid, tissues are exposed to an M1 macrophage developmental microenvironment.

Macrophage Rmp Ameliorates Myocardial Infarction by Modulating Macrophage Polarization in Mice.

Background Inflammation plays important roles during myocardial infarction (MI). Macrophage polarization is a major factor that drives the inflammatory process. Our previous study found that RNA polymerase II subunit 5-mediating protein (RMP) knockout in cardiomyocytes caused heart failure by impairing mitochondrial structure and function. However, whether macrophage RMP plays a role in MI has not been investigated. Methods Macrophage RMP-knockout in combination with a mouse model of MI was used to study the function of macrophage RMP in MI. Next, we modified bone marrow-derived macrophages (BMDMs) by plasmid transfection, and the BMDMs were administered to LysM-Cre/DTR mice by tail vein injection. Immunoblotting and immunofluorescence were used to detect macrophage polarization, fibrosis, angiogenesis, and the p38 signaling pathway in each group. Results Macrophage RMP deficiency aggravates cardiac dysfunction, promotes M1 polarization, and inhibits angiogenesis after MI. However, RMP overexpression in macrophages promotes M2 polarization and angiogenesis after MI. Mechanistically, we found that RMP regulates macrophage polarization through the heat shock protein 90– (HSP90–) p38 signaling pathway. Conclusions Macrophage RMP plays a significant role in MI, likely by regulating macrophage polarization via the HSP90–p38 signaling pathway.

Protective effects of (R)-enantiomers but not (S)-enantiomers of β2-adrenergic receptor agonists against acute colitis: The role of β2AR

The outcomes of ulcerative colitis (UC) treatment remain unsatisfactory. Salbutamol is a β2-adrenergic receptor (β2AR) agonist that is frequently used to treat human airway diseases, and it is a chiral drug with (RS)-isomers. However, the effects of (RS)-enantiomers of this drug on acute ulcerative colitis remain unknown. The present work determined and compared the effects of different chiral β2AR agonists in acute colitis. Acute colitis was established in mice with 3% dextran sulfate sodium and the mice were orally administered different salbutamol isomers. Body weight loss, colon length, disease activity index (DAI), and colon histopathology were assessed. Inflammatory cytokine levels were detected by ELISA. Colonic biopsies were collected from colitis patients. 16S rDNA amplicon sequencing was carried out to assess the composition and relative abundance of the gut microbiome. The expression of M1 and M2 macrophage markers in the colon were assessed by immunofluorescence staining and Western blotting. The results revealed that (R)-salbutamol prevented body weight loss and colonic shortening, decreased the DAI and histopathological scores, and reduced splenomegaly and inflammatory cytokine levels significantly better than (RS)-salbutamol and (S)-salbutamol. (R)-salbutamol downregulated levels of inflammatory protein in LPS-induced human colon tissue specimens. Furthermore, (R)-salbutamol ameliorated gut dysbiosis and macrophage polarization in mice with colitis. The β2AR antagonist ICI-118551 reversed the effect of (R)-salbutamol in ameliorating acute colitis. Taken together, (R)-salbutamol ameliorated the mice with acute colitis, which can serve as a new candidate or lead compound for UC treatment.

Fire Needling Acupuncture Suppresses Cartilage Damage by Mediating Macrophage Polarization in Mice with Knee Osteoarthritis.

PurposeMacrophage polarization contributes to the mechanisms of treating knee osteoarthritis (KOA). In previous studies, fire needling acupuncture has been shown to affect KOA favorably. However, the mechanism of fire needling acupuncture on macrophage polarization is not well-defined. Thus, this study was conducted to determine that fire needling acupuncture exerts a therapeutic role in KOA by modulating macrophage polarization.MethodsThirty mice were allocated at random into three groups of ten. The groups were labeled as “control”, “model”, and “fire needling acupuncture”. Each group consisted of ten mice. From the second day of intra-articular injection MIA, the right “xiyan” (EX-LE5), “dubi” (ST35), “liangqiu” (ST34), and “xuehai” (SP10) acupoints were manipulated once every other day for two weeks in the fire needling acupuncture group. Mechanical withdrawal threshold and weight distribution were evaluated for behavioral testing in each group. The synovial morphology was monitored by HE staining. Pathological morphology was observed by HE staining, Saf-O staining, and toluidine blue staining. The polarization of macrophages in synovial tissue was detected using immunofluorescence (F4/80, CD86, and CD206).ResultsFire needling acupuncture increased the percentage weight-bearing difference and the mechanical withdrawal threshold, and improved synovial inflammation and cartilage damage in MIA-induced KOA mice. F4/80 and CD86 expression were downregulated by fire needling acupuncture, but CD206 was increased.ConclusionFire needling acupuncture decreases pain behaviors in KOA mice and improves synovial membrane injury and pathological cartilage damage. The macrophage polarization is involved in the mechanism of fire needling acupuncture’s amelioration of articular cartilage damage.

Mechanism of protection from insulin resistance by toll-like receptor 2 deficiency in high-fat diet fed mice: involvement in macrophage polarization.

Toll-like receptor 2 (TLR2) deficiency can increase insulin sensitivity and improves glucose tolerance. However, it is not yet fully understood about its underlying mechanism. The regulation of M1/M2 macrophage polarization has been verified to involve in insulin resistance. Here, we evaluated whether the beneficial effect of TLR2 deficiency is mediated by TLR2-associated macrophage polarization in mice fed with high-fat diet (HFD). Wild-type and TLR2 knockout (TLR2-/-) mice received HFD for two months. Following intraperitoneal glucose tolerance and insulin resistance tests, peripheral monocytes were isolated, and in vitro induced for differentiation into M1 and M2 macrophages, respectively. Macrophages polarization was evaluated using flow cytometry. The expression of macrophage polarization marker genes and cytokine production in visceral adipose tissue were measured by qRT-PCR and ELISA. Compared to wild-type mice, TLR2-/- mice showed higher glucose tolerance and insulin sensitivity, along with significantly reduced the population of M1 and increased M2 count in vitro. Additionally, TLR2-/- mice demonstrated higher expression of M2 marker iNOS mRNA and interleukin-10 level in adipose tissues. Our results reveal that TLR2 knockout-mediated macrophages M2 polarization is a crucial factor for preventing against diet-induced insulin resistance in mice. These findings deepen our knowledge about the mechanism underlying HFD-induced insulin resistance.

Hyperoside Suppresses Renal Inflammation by Regulating Macrophage Polarization in Mice With Type 2 Diabetes Mellitus.

Accumulating evidence reveals that both inflammation and lymphocyte dysfunction play a vital role in the development of diabetic nephropathy (DN). Hyperoside (HPS) or quercetin-3-O-galactoside is an active flavonoid glycoside mainly found in the Chinese herbal medicine Tu-Si-Zi. Although HPS has a variety of pharmacological effects, including anti-oxidative and anti-apoptotic activities as well as podocyte-protective effects, its underlying anti-inflammatory mechanisms remain unclear. Herein, we investigated the therapeutic effects of HPS on murine DN and the potential mechanisms responsible for its efficacy. We used C57BLKS/6J Lep db/db mice and a high glucose (HG)-induced bone marrow-derived macrophage (BMDM) polarization system to investigate the potentially protective effects of HPS on DN. Our results showed that HPS markedly reduced diabetes-induced albuminuria and glomerular mesangial matrix expansion, accompanied with a significant improvement of fasting blood glucose level, hyperlipidaemia and body weight. Mechanistically, pretreatment with HPS effectively regulated macrophage polarization by shifting proinflammatory M1 macrophages (F4/80+CD11b+CD86+) to anti-inflammatory M2 ones (F4/80+CD11b+CD206+) in vivo and in bone marrow-derived macrophages (BMDMs) in vitro, resulting in the inhibition of renal proinflammatory macrophage infiltration and the reduction in expression of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor (TNF-α) and inducible nitric oxide synthase (iNOS) while increasing expression of anti-inflammatory cytokine Arg-1 and CD163/CD206 surface molecules. Unexpectedly, pretreatment with HPS suppressed CD4+ T cell proliferation in a coculture model of IL-4-induced M2 macrophages and splenic CD4+ T cells while promoting their differentiation into CD4+IL-4+ Th2 and CD4+Foxp3+ Treg cells. Taken together, we demonstrate that HPS ameliorates murine DN via promoting macrophage polarization from an M1 to M2 phenotype and CD4+ T cell differentiation into Th2 and Treg populations. Our findings may be implicated for the treatment of DN in clinic.

Receptor-selective interleukin-4 mutein attenuates laser-induced choroidal neovascularization through the regulation of macrophage polarization in mice.

Macrophage polarization has been recognized as an important inflammatory regulator in choroidal neovascularization (CNV). However, the mechanisms regulating macrophage activation and polarization, as well as their effects on angiogenesis and CNV, have not yet been elucidated. IL-4 is implicated in macrophage activation and exerts different functions in various diseases through several receptors. In the current study, the effect of IL-4 muteins on CNV was investigated in vivo. CNV was induced by laser coagulation in wild type mice. IL-4 muteins were recombined into adenoviruses and injected into mice via the tail vein. To evaluate CNV, fluorescein fundus angiography and optical coherence tomography were performed on day 7 after coagulation. Quantitative PCR, western blotting and immunofluorescence staining were used to assess the levels of inflammatory markers. AdIL-4/Q116E, an adenovirus-expressed recombinant IL-4 mutein, selectively activated macrophages, alleviated laser-induced CNV in mice with reduced expression of M2 macrophages and increased the expression of M1 macrophages. Furthermore, the expression of monocyte to macrophage differentiation-associated and delta-like 4 (Dll4) in CNV lesions was upregulated. Employing AdIL-4/Q116E, a IL-4RI-selective mutein, may serve as a new strategy for CNV therapy. Moreover, the results indicated that Dll4 signaling served an important role in the regulation of macrophage polarization.

Bone formation recovery with gold nanoparticle-induced M2 macrophage polarization in mice

The prevention of fractures induced by inflammatory bone disease remains a clinical challenge. This is because of a lack of bone formation to fill in the bone defects, which are believed to be due in part to persistent inflammation caused by the imbalance of M1 over M2 macrophages. In this study, gold nanoparticles (AuNPs) were synthesized to shift the balance of macrophages at the site of bone damage to improve osteanagenesis in a mouse model of LPS-induced inflammatory bone erosion. Specifically, the AuNPs treatment improved bone structure and increased bone mineral density (BMD) by ~14% compared with model group. Macrophages recruited by LPS treatment were reduced by ~11% after AuNPs injection. Compared to LPS treatment only, the percentage of M2 macrophages increased threefold by AuNPs, while the proportion of M1 macrophages decreased by 59%. This promoted the regeneration of bone matrix proteins in the bone defect site, which finally leads to increased bone mass and improved bone structure in model mice. These data suggest that AuNPs could be a novel candidate therapeutic for inflammatory bone disease rather than a drug carrier.

Magnoliae Cortex Alleviates Muscle Wasting by Modulating M2 Macrophages in a Cisplatin-Induced Sarcopenia Mouse Model.

Cachexia causes high mortality, low quality of life, and rapid weight loss in cancer patients. Sarcopenia, a condition characterized by the loss of muscle, is generally present in cachexia and is associated with inflammation. M2 macrophages, also known as an anti-inflammatory or alternatively activated macrophages, have been shown to play a role in muscle repair. Magnoliae Cortex (M.C) is a widely used medicinal herb in East Asia reported to have a broad range of anti-inflammatory activities; however, the effects of M.C on sarcopenia and on M2 macrophage polarization have to date not been studied. This study was designed to investigate whether the oral administration of M.C could decrease cisplatin-induced sarcopenia by modulating M2 macrophage polarization in mice. C57BL/6 mice were injected intraperitoneally with cisplatin (2.5 mg/kg) to mimic chemotherapy-induced sarcopenia. M.C extract (50, 100, and 200 mg/kg) was administered orally every 3 days (for a total of 12 times). M.C (100 and 200 mg/kg) significantly alleviated the cisplatin-induced loss of body mass, skeletal muscle weight, and grip strength. In addition, M.C increased the expression of M2 macrophage markers, such as MRC1, CD163, TGF-β, and Arg-1, and decreased the expression of M1-specific markers, including NOS2 and TNF-α, in skeletal muscle. Furthermore, the levels of like growth factor-1(IGF-1), as well as the number of M2a and M2c macrophages, significantly increased in skeletal muscle after M.C administration. M.C did not interfere with the anticancer effect of cisplatin in colon cancer. Our results demonstrated that M.C can alleviate cisplatin-induced sarcopenia by increasing the number of M2 macrophages. Therefore, our findings suggest that M.C could be used as an effective therapeutic agent to reverse or prevent cisplatin-induced sarcopenia.

ADAP Y571 Phosphorylation Is Required to Prime STAT3 for Activation in TLR4-Stimulated Macrophages.

Adhesion and degranulation-promoting adapter protein (ADAP), originally identified as an essential adaptor molecule in TCR signaling and T cell adhesion, has emerged as a critical regulator in innate immune cells such as macrophages; however, its role in macrophage polarization and inflammatory responses remains unknown. In this study, we show that ADAP plays an essential role in TLR4-mediated mouse macrophage polarization via modulation of STAT3 activity. Macrophages from ADAP-deficient mice exhibit enhanced M1 polarization, expression of proinflammatory cytokines and capacity in inducing Th1 responses, but decreased levels of anti-inflammatory cytokines in response to TLR4 activation by LPS. Furthermore, overexpression of ADAP enhances, whereas loss of ADAP reduces, the LPS-mediated phosphorylation and activity of STAT3, suggesting ADAP acts as a coactivator of STAT3 activity and function. Furthermore, the coactivator function of ADAP mostly depends on the tyrosine phosphorylation at Y571 in the motif YDSL induced by LPS. Mutation of Y571 to F severely impairs the stimulating effect of ADAP on STAT3 activity and the ability of ADAP to inhibit M1-like polarization in TLR4-activated mouse macrophages. Moreover, ADAP interacts with STAT3, and loss of ADAP renders mouse macrophages less sensitive to IL-6 stimulation for STAT3 phosphorylation. Collectively, our findings revealed an additional layer of regulation of TLR4-mediated mouse macrophage plasticity whereby ADAP phosphorylation on Y571 is required to prime STAT3 for activation in TLR4-stimulated mouse macrophages.

The miR-23a∼27a∼24-2 microRNA Cluster Promotes Inflammatory Polarization of Macrophages.

Macrophages are critical for regulating inflammatory responses. Environmental signals polarize macrophages to either a proinflammatory (M1) state or an anti-inflammatory (M2) state. We observed that the microRNA (miRNA) cluster mirn23a, coding for miRs-23a, -27a, and -24-2, regulates mouse macrophage polarization. Gene expression analysis of mirn23a-deficient myeloid progenitors revealed a decrease in TLR and IFN signaling. Mirn23a -/- bone marrow-derived macrophages (BMDMs) have an attenuated response to LPS, demonstrating an anti-inflammatory phenotype in mature cells. In vitro, mirn23a-/- BMDMs have decreased M1 responses and an enhanced M2 responses. Overexpression of mirn23a has the opposite effect, enhancing M1 and inhibiting M2 gene expression. Interestingly, expression of mirn23a miRNAs goes down with inflammatory stimulation and up with anti-inflammatory stimulation, suggesting that its regulation prevents locking macrophages into polarized states. M2 polarization of tumor-associated macrophages (TAMs) correlates with poor outcome for many tumors, so to determine if there was a functional consequence of mirn23a loss modulating immune cell polarization, we assayed syngeneic tumor growth in wild-type and mirn23a -/- mice. Consistent with the increased anti-inflammatory/immunosuppressive phenotype in vitro, mirn23a -/- mice inoculated with syngeneic tumor cells had worse outcomes compared with wild-type mice. Coinjecting tumor cells with mirn23a -/- BMDMs into wild-type mice phenocopied tumor growth in mirn23a -/- mice, supporting a critical role for mirn23a miRNAs in macrophage-mediated tumor immunity. Our data demonstrate that mirn23a regulates M1/M2 polarization and suggests that manipulation of mirn23a miRNA can be used to direct macrophage polarization to drive a desired immune response.

Sult2b1 deficiency exacerbates ischemic stroke by promoting pro-inflammatory macrophage polarization in mice.

Rationale: Stroke is a leading causes of human death worldwide. Ischemic damage induces the sterile neuroinflammation, which directly determines the recovery of patients. Lipids, a major component of the brain, significantly altered after stroke. Cholesterol sulfate, a naturally occurring analog of cholesterol, can directly regulate immune cell activation, indicating the possible involvement of cholesterol metabolites in neuroinflammation. Sulfotransferase family 2b member 1 (Sult2b1) is the key enzyme that catalyzes the synthesis of cholesterol sulfate. This study aimed to investigate the function of Sult2b1 and cholesterol sulfate in the neuroinflammation after ischemic stroke.Methods and Results: Sult2b1-/- and wild-type mice were subjected to transient middle cerebral artery occlusion. Our data showed that Sult2b1-/- mice had larger infarction and worse neurological scores. To determine whether immune cells were involved in the worsening stroke outcome in Sult2b1-/- mice, bone marrow transplantation, immune cell depletion, and adoptive monocyte transfer were performed. Combined with CyTOF and immunofluorescence techniques, we demonstrated that after stroke, the peripheral monocyte-derived macrophages were the dominant cell type promoting the pro-inflammatory status in Sult2b1-/-mice. Using primary bone marrow-derived macrophages, we showed that cholesterol sulfate could attenuate the pro-inflammatory polarization of macrophages under both normal and oxygen-glucose deprivation conditions by regulating the levels of nicotinamide adenine dinucleotide phosphate (NADPH), reactive oxygen species (ROS), and activating the AMP-activated protein kinase (AMPK) - cAMP responsive element-binding protein (CREB) signaling pathway.Conclusions: Sult2b1-/- promoted the polarization of macrophages into pro-inflammatory status. This trend could be attenuated by adding cholesterol sulfate, which promotes the polarization of macrophages into anti-inflammatory status by metabolic regulation. In this study, we established an inflammation-metabolism axis during the macrophage polarization after ischemic stroke.