Altered Macrophage Polarization Research Articles

Staphylococcus epidermidis alters macrophage polarization and phagocytic uptake by extracellular DNA release in vitro

Biofilm formation shields Staphylococcus epidermidis from host defense mechanisms, contributing to chronic implant infections. Using wild-type S. epidermidis 1457, a PIA-negative mutant (1457-M10), and an eDNA-negative mutant (1457ΔatlE), this study examined the influence of biofilm matrix components on human monocyte-derived macrophage (hMDM) interactions. The wild-type strain was resistant to phagocytosis and induced an anti-inflammatory response in hMDMs, while both mutants were more susceptible to phagocytosis and triggered a pro-inflammatory response. Removing eDNA from the 1457 biofilm matrix increased hMDM uptake and a pro-inflammatory reaction, whereas adding eDNA to the 1457ΔatlE mutant reduced phagocytosis and promoted an anti-inflammatory response. Inhibiting TLR9 enhanced bacterial uptake and induced a pro-inflammatory response in hMDMs exposed to wild-type S. epidermidis. This study highlights the critical role of eDNA in immune evasion and the central role of TLR9 in modulating macrophage responses, advancing the understanding of implant infections.

EXTH-52. SIMULTANEOUS TARGETING OF TUMOR CELLS AND TUMOR-ASSOCIATED MACROPHAGES TO REPROGRAM GLIOBLASTOMA BY TUMOR-SUPPRESSIVE MICRORNA

Abstract Glioblastoma (GBM) is the most aggressive type of primary brain tumors due in part to cell-intrinsic and cell-extrinsic mechanisms. The ability of GBM tumor to not only resist conventional therapies but also induce an immunosuppressive tumor microenvironment (TME) is thought to underlie the failure of immunotherapies. Thus, strategies to target both tumor cells and immunosuppressive immune cells, such as tumor-associated macrophages (TAMs), are of great interest. The ability of microRNA (miRNA) to target multiple genes is favorable to alter the character of the TME and cancer cells. Previously, we have shown that tumor suppressive miRNA, miR-138, can effectively regulate the genes in GBM cells relating to cell proliferation and viability. The exogenous delivery of miRNAs, however, has been limited due to the lack of delivery mechanisms that minimize off target effects. We argue that extracellular vesicles (EVs) are an ideal modality of targeted delivery for therapeutic miRNA, which we can accomplish by decorating the EV surface with cancer specific ligands, such as folate. Here, we report that trypsin digestion of the EV surface can increase the surface labeling efficiency for cancer targeting ligands. Folate-labeled trypsinized EVs effectively targeted folate receptor (FR) positive GBM cells and TAMs, delivering miR-138 in in vitro and in vivo orthotopic intracranial murine models of GBM. This simultaneous delivery decreased cancer cell proliferation and altered macrophage polarization through the inhibition of known target genes, phenotypically reprogramming both cancer cells and TAMs. To our knowledge, this is the first preclinical study attempting to target both tumor cells and innate immunity by delivering tumor suppressive miR-138 using a trypsinized EV-based RNA delivery system. These findings can be rapidly translated into a novel therapeutic option for GBM patients.

Altered Bone Marrow Dynamics and Macrophage Polarization: Implications for Skeletal Health in Chronic Kidney Disease

Altered Bone Marrow Dynamics and Macrophage Polarization: Implications for Skeletal Health in Chronic Kidney Disease

MiR-21-3p inhibitor exerts myocardial protective effects by altering macrophage polarization state and reducing excessive mitophagy

Chronic heart failure (CHF) is closely associated with inflammation and mitochondrial dysfunction in cardiomyocytes. This study attempts to investigate the effects of microRNA-21-3p (miR-21-3p) on macrophage polarization and mitophagy in CHF. Here we found miR-21-3p was upregulated in CHF and negatively correlated with carnitine palmitoyl transferase 1A (CPT1A). L-palmitoyl carnitine (L-PC) exacerbated isoproterenol (ISO)-induced myocardial structural disruption and fibrosis in rats, which was exacerbated by miR-21-3p. Mechanistically, miR-21-3p accelerated M1 macrophage polarization. Both miR-21-3p inhibitor and CPT1A overexpression suppressed mitophagy. The inhibition of CPT1A on mitophagy was reversed by miR-21-3p. MiR-21-3p targeted CPT1A mRNA and co-localized with CPT1A protein in cardiomyocytes. In the co-culture system of M1 macrophages and H9c2 cells, miR-21-3p mimics in H9c2 cells promoted M1 polarization, whereas miR-21-3p inhibitor reduced M1 phenotype. M1 macrophages exacerbated H9c2 cell damage. These findings support the potential therapeutic targeting of miR-21-3p to regulate inflammation and mitophagy by inducing CPT1A in CHF.

HIF-1α Pathway Orchestration by LCN2: A Key Player in Hypoxia-Mediated Colitis Exacerbation.

In this study, we investigated the role of hypoxia in the development of chronic inflammatory bowel disease (IBD), focusing on its impact on the HIF-1α signaling pathway through the upregulation of lipocalin 2 (LCN2). Using a murine model of colitis induced by sodium dextran sulfate (DSS) under hypoxic conditions, transcriptome sequencing revealed LCN2 as a key gene involved in hypoxia-mediated exacerbation of colitis. Bioinformatics analysis highlighted the involvement of crucial pathways, including HIF-1α and glycolysis, in the inflammatory process. Immune infiltration analysis demonstrated the polarization of M1 macrophages in response to hypoxic stimulation. In vitro studies using RAW264.7 cells further elucidated the exacerbation of inflammation and its impact on M1 macrophage polarization under hypoxic conditions. LCN2 knockout cells reversed hypoxia-induced inflammatory responses, and the HIF-1α pathway activator dimethyloxaloylglycine (DMOG) confirmed LCN2's role in mediating inflammation via the HIF-1α-induced glycolysis pathway. In a DSS-induced colitis mouse model, oral administration of LCN2-silencing lentivirus and DMOG under hypoxic conditions validated the exacerbation of colitis. Evaluation of colonic tissues revealed altered macrophage polarization, increased levels of inflammatory factors, and activation of the HIF-1α and glycolysis pathways. In conclusion, our findings suggest that hypoxia exacerbates colitis by modulating the HIF-1α pathway through LCN2, influencing M1 macrophage polarization in glycolysis. This study contributes to a better understanding of the mechanisms underlying IBD, providing potential therapeutic targets for intervention.

Lenvatinib targets STAT-1 to enhance the M1 polarization of TAMs during hepatocellular carcinoma progression

Lenvatinib, a multitarget kinase inhibitor, has been proven to be effective in the treatment of advanced hepatocellular carcinoma. It has been previously demonstrated that tumour associated macrophages (TAMs) in tumour tissues can promote HCC growth, invasion and metastasis. Furthermore, lenvatinib has certain immunomodulatory effects on the treatment of HCC. However, the role of lenvatinib in macrophage polarization during HCC treatment has not been fully explored. In this study, we used a variety of experimental methods both in vitro and in vivo to investigate the effect of lenvatinib on TAMs during HCC progression. This study is the first to show that lenvatinib can alter macrophage polarization in both humans and mice. Moreover, macrophages treated with lenvatinib in vitro displayed enhanced classically activated macrophages (M1) activity and suppressed liver cancer cell proliferation, invasion, and migration. Furthermore, during the progression of M1 macrophage polarization induced by lenvatinib, STAT-1 was the main target transcription factor, and inhibiting STAT-1 activity reversed the effect of lenvatinib. Overall, the present study provides a theoretical basis for the immunomodulatory function of lenvatinib in the treatment of HCC.

F1 fraction isolated from Mesobuthus eupeus scorpion venom induces macrophage polarization toward M1 phenotype and exerts anti-tumoral effects on the CT26 tumor cell line

Scorpion venoms identified as agents with anti-tumor and anti-angiogenic features. Tumor microenvironment (TME) plays a pivotal role in the process of tumorigenesis, tumor development, and polarization of M2 phenotype tumor associated macrophages (TAMs). M2 polarized cells are associated with tumor growth, invasion, and metastasis. The fractionation process was performed by gel filtration chromatography on a Sephadex G50 column. To elucidate whether scorpion venom can alter macrophage polarization, we treated interleukin (IL)-4-polarized M2 cells with isolated fractions from Mesobuthus eupeus. Next, we evaluated the cytokine production and specific markers expression for M2 and M1 phenotype using enzyme linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (PCR), respectively. The phagocytic capacity of macrophages was also assessed. In addition, the migration assay and MTT analysis were performed to investigate the effects of reprogrammed macrophages on the CT-26 colon cancer cells. The results indicated that F1 fraction of venom significantly upregulated the levels and expression of M1-associated cytokines and markers, including tumor necrosis factor-alpha (TNF-α) (p < 0.001), IL-1 (p < 0.01), interferon regulatory factor 5 (IRF5) (p < 0.0001), induced nitric oxide synthase (iNOS) (p < 0.0001), and CD86 (p < 0.0001), and downregulated M2-related markers, including transforming growth factor-beta (TGF-β) (p < 0.05), IL-10 (p < 0.05), Fizz1 (p < 0.0001), arginase-1 (Arg-1) (p < 0.0001), and CD206 (p < 0.001). The macrophage phagocytic capacity was enhanced after treatment with F1 fraction (p < 0.01). Moreover, incubation of CT-26 cell line with conditioned media of F1-treated macrophages suppressed migration (p < 0.0001) and proliferation (p < 0.01) of tumor cells. In conclusion, our findings demonstrated the potential of Mesobuthus eupeus venom in M2-to-M1 macrophage polarization as a promising therapeutic approach against proliferation and metastasis of colon cancer cells.

CD4+ and CD8+ T cells reduce inflammation and promote bone healing in response to titanium implants

T cells are adaptive immune cells essential in pathogenic response, cancer, and autoimmune disorders. During the integration of biomaterials with host tissue, T cells modify the local inflammatory environment by releasing cytokines that promote inflammatory resolution following implantation. T cells are vital for the modulation of innate immune cells, recruitment and proliferation of mesenchymal stem cells (MSCs), and formation of functional tissue around the biomaterial implant. We have demonstrated that deficiency of αβ T cells promotes macrophage polarization towards a pro-inflammatory phenotype and attenuates MSC recruitment and proliferation in vitro and in vivo. The goal of this study was to understand how CD4+ and CD8+ T cells, subsets of the αβ T cell family, impact the inflammatory response to titanium (Ti) biomaterials. Deficiency of either CD4+ or CD8+ T cells increased the proportion of pro-inflammatory macrophages, lowered anti-inflammatory macrophages, and diminished MSC recruitment in vitro and in vivo. In addition, new bone formation at the implantation site was significantly reduced in T cell-deficient mice compared to T cell-competent mice. Deficiency of CD4+ T cells exacerbated these effects compared to CD8+ T cell deficiency. Our results show the importance of CD4+ and CD8+ T cells in modulating the inflammatory response and promoting new bone formation in response to modified Ti implants. Statement of significanceCD4+ and CD8+ T cells are essential in modulating the peri-implant microenvironment during the inflammatory response to biomaterial implantation. This study shows that deficiency of either CD4+ or CD8+ T cell subsets altered macrophage polarization and reduced MSC recruitment and proliferation at the implantation site.

Abstract 3015: HD-PTP mediates tumor suppression via modulation of anti-tumor immunity

Abstract The role of circulating extracellular vesicles in cancer biology is an area of intense research interest. Here, we reveal a tumor suppressor mechanism of HD-PTP (His Domain Protein Tyrosine Phosphatase, encoded by PTPN23), a protein associated with ESCRT (endosomal sorting complex required for transport), a complex that controls endosome sorting and exosome secretion. While loss of HD-PTP is known to be tumorigenic in mice and is frequently observed in human cancers including Triple Negative Breast Cancer (TNBC), the relevant pathways have remained obscure. We find that inhibition of HD-PTP in vivo promotes tumor progression selectively in a syngeneic, immune-competent TNBC model but not in a matched immune-deficient model. Through systematic profiling of the exosomal proteome in HD-PTP proficient and deficient cells, we identify PD-L1 as a key exosomal cargo selectively enriched due to loss of HD-PTP. Mechanistically, we show that inhibition of HD-PTP results in PD-L1 stabilization, its co-localization with the exosomal marker CD63, the enrichment of endosomal PD-L1 and subsequent increase in ExoPD-L1 release. Exosomes produced post HD-PTP loss inhibits antigen-dependent T cell activity in vitro, and HD-PTP inhibition in a syngeneic TNBC model promotes non-cell-autonomous, exosome- and PD-L1-dependent tumor progression, associated with reduced T cell infiltration and altered macrophage polarization. Consistent with these findings, low HD-PTP levels in human solid tumors are associated with decreased tumor infiltrating lymphocytes, poor response to immune checkpoint inhibition and inferior overall survival. Taken together, our studies unveil a novel tumor suppressor pathway controlling PD-L1 trafficking and ExoPD-L1 secretion, highlighting the critical roles of HD-PTP and ESCRT in anti-tumor immunity. Citation Format: Chenxu Guo, Sheng Sun, Nayana Thimmiah, Agustina Maccio, Siang Koh, Leif Ellisen. HD-PTP mediates tumor suppression via modulation of anti-tumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3015.

HSPA9 reduction exacerbates symptoms and cell death in DSS-Induced inflammatory colitis

Inflammatory bowel disease (IBD) is a chronic inflammatory condition that is influenced by various factors, including environmental factors, immune responses, and genetic elements. Among the factors that influence IBD progression, macrophages play a significant role in generating inflammatory mediators, and an increase in the number of activated macrophages contributes to cellular damage, thereby exacerbating the overall inflammatory conditions. HSPA9, a member of the heat shock protein 70 family, plays a crucial role in regulating mitochondrial processes and responding to oxidative stress. HSPA9 deficiency disrupts mitochondrial dynamics, increasing mitochondrial fission and the production of reactive oxygen species. Based on the known functions of HSPA9, we considered the possibility that HSPA9 reduction may contribute to the exacerbation of colitis and investigated its relevance. In a dextran sodium sulfate-induced colitis mouse model, the downregulated HSPA9 exacerbates colitis symptoms, including increased immune cell infiltration, elevated proinflammatory cytokines, decreased tight junctions, and altered macrophage polarization. Moreover, along with the increased mitochondrial fission, we found that the reduction in HSPA9 significantly affected the superoxide dismutase 1 levels and contributed to cellular death. These findings enhance our understanding of the intricate mechanisms underlying colitis and contribute to the development of novel therapeutic approaches for this challenging condition.

HTRA2/OMI-Mediated Mitochondrial Quality Control Alters Macrophage Polarization Affecting Systemic Chronic Inflammation.

Systemic chronic inflammation (SCI) due to intrinsic immune over-activation is an important factor in the development of many noninfectious chronic diseases, such as neurodegenerative diseases and diabetes mellitus. Among these immune responses, macrophages are extensively involved in the regulation of inflammatory responses by virtue of their polarization plasticity; thus, dysregulation of macrophage polarization direction is one of the potential causes of the generation and maintenance of SCI. High-temperature demand protein A2 (HtrA2/Omi) is an important regulator of mitochondrial quality control, not only participating in the degradation of mis-accumulated proteins in the mitochondrial unfolded protein response (UPRmt) to maintain normal mitochondrial function through its enzymatic activity, but also participating in the regulation of mitochondrial dynamics-related protein interactions to maintain mitochondrial morphology. Recent studies have also reported the involvement of HtrA2/Omi as a novel inflammatory mediator in the regulation of the inflammatory response. HtrA2/Omi regulates the inflammatory response in BMDM by controlling TRAF2 stabilization in a collagen-induced arthritis mouse model; the lack of HtrA2 ameliorates pro-inflammatory cytokine expression in macrophages. In this review, we summarize the mechanisms by which HtrA2/Omi proteins are involved in macrophage polarization remodeling by influencing macrophage energy metabolism reprogramming through the regulation of inflammatory signaling pathways and mitochondrial quality control, elucidating the roles played by HtrA2/Omi proteins in inflammatory responses. In conclusion, interfering with HtrA2/Omi may become an important entry point for regulating macrophage polarization, providing new research space for developing HtrA2/Omi-based therapies for SCI.

Three‐dimensional printed biomimetic multilayer scaffolds coordinated with sleep‐related small extracellular vesicles: A strategy for extracellular matrix homeostasis and macrophage polarization to enhance osteochondral regeneration

AbstractCartilage defects resulting from injury or degeneration are a common clinical problem, and due to its avascular nature, articular cartilage has poor self‐healing capacity. Three‐dimensional (3D) bioprinting has attracted great attention in tissue engineering. Melatonin (MT), a hormone mainly secreted at night, plays an important role in tissue repair. Small extracellular vesicles (sEV) are considered ideal drug delivery vehicles and MT‐sEV (sleep‐related sEV) have the potential ability to promote cartilage regeneration. Here, biomimetic multilayer scaffolds were fabricated using 3D bioprinting. A double network hydrogel, composed of methacrylated hyaluronic acid and gelatin methacryloyl (HG), was prepared. MT‐sEV and HG hydrogel were used to create a cartilage layer. A bone layer was formed using poly(ε‐caprolactone) and hydroxyapatite ultralong nanowires. Additionally, two bioinks were alternately printed at the interface layer. The results of RNA sequencing revealed the potential regulatory mechanisms. MT‐sEV showed promotional effects on cell migration, proliferation, chondrogenic differentiation, and extracellular matrix (ECM) deposition. Moreover, MT‐sEV altered macrophage polarization and regulated the expression of inflammatory cytokines. In vivo experiments demonstrated that the biomimetic multilayer scaffolds promoted cartilage regeneration. These experiments demonstrated the ability of MT‐sEV to regulate the immune microenvironment and promote the secretion of ECM, providing a promising strategy for cartilage regeneration.

Small extracellular vesicles from hypoxia-preconditioned bone marrow mesenchymal stem cells attenuate spinal cord injury via miR-146a-5p-mediated regulation of macrophage polarization.

JOURNAL/nrgr/04.03/01300535-202410000-00027/figure1/v/2024-02-06T055622Z/r/image-tiff Spinal cord injury is a disabling condition with limited treatment options. Multiple studies have provided evidence suggesting that small extracellular vesicles (SEVs) secreted by bone marrow mesenchymal stem cells (MSCs) help mediate the beneficial effects conferred by MSC transplantation following spinal cord injury. Strikingly, hypoxia-preconditioned bone marrow mesenchymal stem cell-derived SEVs (HSEVs) exhibit increased therapeutic potency. We thus explored the role of HSEVs in macrophage immune regulation after spinal cord injury in rats and their significance in spinal cord repair. SEVs or HSEVs were isolated from bone marrow MSC supernatants by density gradient ultracentrifugation. HSEV administration to rats via tail vein injection after spinal cord injury reduced the lesion area and attenuated spinal cord inflammation. HSEVs regulate macrophage polarization towards the M2 phenotype in vivo and in vitro. MicroRNA sequencing and bioinformatics analyses of SEVs and HSEVs revealed that miR-146a-5p is a potent mediator of macrophage polarization that targets interleukin-1 receptor-associated kinase 1. Reducing miR-146a-5p expression in HSEVs partially attenuated macrophage polarization. Our data suggest that HSEVs attenuate spinal cord inflammation and injury in rats by transporting miR-146a-5p, which alters macrophage polarization. This study provides new insights into the application of HSEVs as a therapeutic tool for spinal cord injury.

Diosgenin alters LPS-induced macrophage polarization by activating PPARγ/NF-κB signaling pathway

Diosgenin (DG) is a steroidal saponin derived from plants, and it exhibits anti-inflammatory properties. In this study, we employed an in vitro model of P.g.-LPS-stimulated mouse macrophage cell line RAW264.7 to investigate the anti-inflammatory effects and mechanism of DG under the condition of altered polarization of macrophages. The RAW264.7 cells were subjected to pre-treatment with DG with or without P.g.-LPS. In cultured macrophages, DG inhibited P.g.-LPS-induced pro-inflammatory M1 macrophages, and increased anti-inflammatory M2 macrophages. Notably, DG reduced the expression of phosphorylation levels of NF-κB p65 and IκB while increasing the expression of PPARγ. Further studies revealed that PPARγ inhibitor GW9662 or PPARγ siRNA reversed the inhibitory effect of DG on M1 phenotype. Collectively, the anti-inflammatory mechanism of DG is related to altering macrophage polarization by activating PPARγ and inhibiting NF-κB signaling pathways.

Exercise-mediated macrophage polarization modulates the targeted therapeutic effect of NAFLD: a review.

This review aims to explore the exercise-mediated hepatic macrophage polarization mechanism and its effect on improving and regulating non-alcoholic fatty liver disease (NAFLD) by analyzing the pathogenesis of NAFLD and the cause of the influence of hepatic macrophage polarization. In addition to exploring the varied effects of different exercise types on macrophage polarization regulation in NAFLD, to provide a direction and basis for the treatment of NAFLD. The research methodology involved a comprehensive search of the PubMed database using specific keywords such as "NAFLD", "macrophage polarization", and "exercise", to retrieve relevant literature published. (1) The main factors inducing NAFLD were high-fat diet, obesity, insulin resistance (IR), changes in gut microbiota, and genetic variation in susceptibility. (2) Drug treatment, nutrient induction, microfactor induction, physiological environment induction, and other factors can induce the polarization of hepatic macrophages and affect NAFLD. (3) Different intensities, types, and frequencies of exercise have different effects on polarization macrophages, and may also differently effects improving liver inflammation, fibrosis, and NAFLD. Curently, regular moderate-intensity aerobic exercise is the most effective therapy for treating NAFLD. Approaches to ameliorate NAFLD with exercise involve strategies to alter macrophage polarization by inhibiting M1 or driving M2 activation. However, research on the different types of exercise-mediated macrophage polarization mechanisms and differences in therapeutic effects is not yet sufficient. Future research is necessary to explore the exact mechanisms and differences in the effects of different exercises on the treatment of NAFLD.

Abstract P185: Hydralazine Treatment Does Not Fully Reduce Proinflammatory Immune Cells In The Ovaries Of Mice With Salt-sensitive Hypertension

Salt-sensitive hypertension (SSHTN) is associated with altered macrophage polarization, inflammation, and inflammation-associated lymphangiogenesis in the ovaries of mice, and this is associated with reproductive dysfunction. However, it is unknown whether high pressure or salt or both are involved in these adverse effects. We hypothesized that lowering of blood pressure will not reduce proinflammatory immune cells and inflammation in the ovaries of mice with SSHTN. Female C57BL6/J mice were divided into 3 groups: Control (C) mice received tap water and normal diet; SSHTN mice received L-NAME (0.5 mg/mL) in the drinking water for 2 weeks, followed by a 2-week washout period, and a subsequent 3-week 4% salt diet; and the third group were SSHTN and received hydralazine (250 mg/L) in their drinking water (HYD) during the last 3 weeks of salt diet. There was a significant increase in systolic blood pressure in SSHTN mice (143±2 mm Hg) when compared to control (99±2 mm Hg) but was reduced significantly in HYD mice (119±1 mm Hg). Flow cytometry analysis revealed a significant increase in M1 macrophages in the ovaries of SSHTN and HYD mice when compared to C mice (% of CD45 cells: C: 25%±2, SSHTN: 37.8%±2, HYD: 36.2%±3; p&lt;0.05). There was an increase in CD4+TNFa+IFNg+ Th1 cells in the ovaries of SSHTN and HYD mice when compared to C mice (C: 0.33%±0.06, SSHTN: 0.8%±0.07, HYD: 0.7%±0.1; p&lt;0.05), whereas CD4+ T cells (C: 26.5%±2, SSHTN: 51.5%±4, HYD: 14.7%±3; p&lt;0.05) and CD4+IL17a+ Th17 cells (C: 2.9%±0.2, SSHTN: 5.4%±1, HYD: 3.1%±0.6; p&lt;0.05) significantly increased in SSHTN mice but were reduced in HYD mice. Increased gene expression of IL-17 and iNOS was observed in the ovaries of SSHTN and HYD mice. Together, these data demonstrate that both high blood pressure and salt exert their effect on immune cells differentially contributing to the ovarian dysfunction in SSHTN mice. Further studies are needed to investigate whether manipulating macrophage polarization could reverse these adverse effects in the ovaries of mice with SSHTN.

Abstract P184: Inducing Macrophages Towards A Regulatory Phenotype Reduces Blood Pressure And Testicular Proinflammatory Immune Cells In Hypertensive Mice

Our laboratory has previously reported that salt-sensitive hypertension (SSHTN) induces proinflammatory macrophages, inflammation, and inflammation-associated lymphangiogenesis in the testes of mice. However, it is unknown whether altered macrophage polarization causes these changes leading to testicular dysfunction. We hypothesized that inducing macrophages towards a regulatory phenotype will lower blood pressure and reverse inflammation in the testes that is associated with SSHTN. Control (C) male C57BL6/J mice received tap water and normal diet. SSHTN mice were provided L-NAME (0.5 mg/mL) in the drinking water for 2 weeks, followed by a 2-week washout period, and a subsequent 3-week 4% high salt diet and mice in the third group received AVE0991 (0.58 nmol/g) through i.p injections (AVE) in the last 3 weeks. SSHTN mice had increased systolic blood pressure (146±2 mm Hg) when compared to C mice (96±2 mm Hg), but the blood pressure was reduced in AVE mice (136±1 mm Hg; p&lt;0.05). Flow cytometry analysis revealed a significant reduction in M2 macrophages in the testes of SSHTN mice when compared to C mice but were increased in AVE mice when compared to SSHTN mice (% of CD45 cells: C: 19.3%±2, SSHTN: 7.7%±2, AVE: 15.7%±3; p&lt;0.05). There was an increase in CD45+ F4/80- CD11c+ dendritic cells (C:3.3%±1, SSHTN:6.7%±1, AVE: 3.1%±1; p&lt;0.05), CD4+ IL17+ Th17 cells (C:5.8%±1, SSHTN:28.5%±3, AVE: 10.6%±3; p&lt;0.05), CD4+ TNFa+ Th1 cells (C:11.8%±2, SSHTN:38.8%±8, AVE: 15.2%±3; p&lt;0.05), and gamma-delta T cells (C:2.9%±1, SSHTN:8.9%±2, AVE: 4.9%±1; p&lt;0.05) in the testes of SSHTN mice when compared to C mice, but were decreased significantly in AVE mice. These data demonstrate that alteration in testicular macrophage phenotypes is a contributing factor to testicular inflammation resulting in reproductive dysfunction in SSHTN mice. Therapeutic strategies may be developed by targeting macrophage imbalance to improve testicular function that is associated with SSHTN.

SCARB1 in extracellular vesicles promotes NPC metastasis by co-regulating M1 and M2 macrophage function

Distant metastasis is currently the main factor affecting the prognosis of nasopharyngeal carcinoma (NPC), and understanding the mechanisms of metastasis and identifying reliable therapeutic targets are critical for improving prognosis and achieving clinical translation. Macrophages, as important immune cells in the tumor microenvironment (TME), have been shown to regulate metastasis. And extracellular vesicles (EVs) secreted by stromal cells and tumor cells play the important role in intercellular communication in the tumor microenvironment. However, the role of NPC-EVs on macrophages and their function in regulating macrophages to affect metastasis has not been fully clarified. In this study, we report that NPC-EVs can be uptake by macrophages and alter macrophage polarization, for the first time, we identified the genes implicated in these regulatory functions: SCARB1, HAAO, and CYP1B1. Moreover, we found that SCARB1 was positively associated with metastasis and poor prognosis of NPC. Interestingly, we found that SCARB1-rich EVs promoted M1 macrophages ferroptosis to decrease M1 macrophages infiltration by upregulating the HAAO level while decreasing phagocytosis of M2 macrophages by upregulating the CYP1B1 level. Finally, we identified the SCARB1-binding gene KLF9, which is involved in the transcription of HAAO and CYP1B1. Our findings showed that SCARB1-EVs promoted metastasis by co-regulating M1 and M2 macrophage function. The related mechanism will provide a new therapeutic strategy to help patients with NPC improve their prognosis.

Integrin β6 deficiency protects mice from experimental colitis and colitis-associated carcinoma by altering macrophage polarization.

Given the key role of integrins in maintaining intestinal homeostasis, anti-integrin biologics in inflammatory bowel disease (IBD) are being investigated in full swing. However, the unsatisfactory efficacy and safety of current anti-integrin biologics in clinical trials limit their widespread use in clinic. Therefore, it is particularly important to find a target that is highly and specifically expressed in the intestinal epithelium of patients with IBD. The function of integrin αvβ6 in IBD and colitis-associated carcinoma (CAC) with the underlying mechanisms has been less studied. In the present study, we detected the level of integrin β6 within inflammation including colitis tissues in human and mouse. To investigate the role of integrin β6 in IBD and CAC, integrin β6 deficient mice were hence generated based on the construction of colitis and CAC model. We noted that integrin β6 was significantly upregulated in inflammatory epithelium of patients with IBD. Integrin β6 deletion not only reduced infiltration of pro-inflammatory cytokines, but also attenuated disruption of tight junctions between colonic epithelial cells. Meanwhile, lack of integrin β6 affected macrophage infiltration in mice with colitis. This study further revealed that lack of integrin β6 could inhibit tumorigenesis and tumor progression in CAC model by influencing macrophage polarization, which was also involved in attenuating the degree of intestinal symptoms and inflammatory responses in mice suffering from colitis. The present research provides a potentially new perspective and option for the treatment of IBD and CAC.

Auriculotherapy Modulates Macrophage Polarization to Reduce Inflammatory Response in a Rat Model of Acne.

The inflammatory response is an important part of the pathogenesis of acne vulgaris. Auriculotherapy has been shown to have a good therapeutic effect on this disease. The aim of this study was to explore the mechanism underlying the anti-inflammatory effect of auriculotherapy in the treatment of acne vulgaris. Propionibacterium acnes was injected subcutaneously into the ears of rats to establish an animal model of acne. The auriculotherapy intervention in rats consisted of auricular bloodletting therapy (ABT), auricular point sticking (APS), or a combination of both (ABPS). The anti-inflammatory effects of auriculotherapy were evaluated by measuring changes in ear thickness, local body surface microcirculation in the ear, and serum inflammatory factors in rats. The polarization of macrophages was analyzed by flow cytometry, and the expression of TLR2/NF-κB signaling pathway in the target tissues was analyzed using western blot. ABT, APS, and ABPS all reduced the erythema of ear acne, decreased microcirculation in localized ear acne, and decreased serum levels of TNF-α and IL-1β in rats. Meanwhile, the three interventions reduced M1-type macrophages and increased M2-type macrophages; only APS could reduce the expression of TLR2/NF-κB signaling pathway. ABT, APS, and ABPS can improve the inflammatory symptoms of acne and reduce inflammatory cytokines. APS may exert anti-inflammatory effects by altering macrophage polarization and decreasing TLR2/NF-κB expression.