Promoted Macrophage Migration Research Articles

The protective effects of apelin-13 in HIV-1 tat- induced macrophage infiltration and BBB impairment

ABSTRACT Impairment of the blood – brain barrier (BBB) and subsequent inflammatory responses contribute to the development of human immunodeficiency virus (HIV)-1-associated neurocognitive disorders (HAND). Apelin-13, the most abundant member of the apelin family, acts as the ligand of the angiotensin receptor-like 1 (APJ). However, its pharmacological function in HAND and its underlying mechanism are unknown. In the current study, we report that the presence of HIV-1 Tat reduced the levels of Apelin-13 and APJ in the cortex tissue of mice. Importantly, Apelin-13 preserved BBB integrity against HIV-1 Tat in mice by increasing the expression of the tight junction protein zonula occludens-1 (ZO-1) and occludin. Interestingly, increased macrophage infiltration, indicated by elevated CD68-positive staining was observed in the cortex after stimulation with HIV-1, which was mitigated by the administration of Apelin-13. Correspondingly, Apelin-13 reduced the expression of monocyte chemoattractant protein-1; (MCP-1). An in vitro two-chamber and two-cell trans-well assay demonstrated that HIV-1 Tat challenge significantly promoted macrophage migration, which was notably attenuated by the introduction of Apelin-13. Accordingly, treatment with Apelin-13 restored the HIV-1 Tat-induced reduction of occludin and ZO-1, while preventing the upregulation of MCP-1 in human brain microvascular endothelial cells (HBMVECs). Our results suggest that Apelin-13 may reduce macrophage infiltration into brain tissues and mitigate BBB dysfunction in patients with HAND.

SRGN promotes macrophage recruitment through CCL3 in osteoarthritis

ABSTRACT Background Osteoarthritis (OA) is a degenerative disease that affects synovial joints and leads to significant pain and disability, particularly in older adults. Infiltration of macrophages plays a key role in the progression of OA. However, the mechanisms underlying macrophage recruitment in OA are not fully understood. Methods The Serglycin (SRGN) expression pattern was analyzed, along with its association with macrophage infiltration in OA, using bioinformatic methods. SRGN expression in chondrocytes was altered by small interfering RNA (siRNA) and plasmids. Conditioned media (CM) was obtained from transfected chondrocytes to establish a co-culture model of chondrocytes and THP-1 derived macrophages. The impact of SRGN on macrophage recruitment was evaluated using a transwell assay. Furthermore, the regulatory effect of SRGN on CCL3 was validated through qPCR, WB, and ELISA experiments. Results In OA patients, the upregulation of SRGN positively correlated with K-L grade and macrophage infiltration. It was found that SRGN expression and secretion were up-regulated in OA and that it can promote macrophage migration in vitro. Further investigation showed that SRGN affects macrophage migration by regulating the expression of CCL3. Conclusion SRGN in chondrocytes plays a role in promoting the recruitment of THP-1 derived macrophages in vitro by regulating production of CCL3.

β-Cyclodextrin and Hyaluronic Acid-Modified Targeted Nanodelivery System for Atherosclerosis Prevention.

Natural products have been widely recognized in clinical treatment because of their low toxicity and high activity. It is worth paying attention to modifying the biopolymer into nanostructures to give natural active ingredients additional targeting effects. In this study, based on the multifunctional modification of β-cyclodextrin (β-CD), a nanoplatform encapsulating the unstable drug (-)-epicatechin gallate (ECG) was designed to deliver to atherosclerotic plaques. Acetalization cyclodextrin (PH-CD), which responds to low-pH environments, and hyaluronic acid cyclodextrin, which targets the CD44 receptor on macrophage membranes, were synthesized from β-CD and hyaluronic acid using acetalization and transesterification, respectively. The resulting dual-carrier nanoparticles (Double-NPs) loaded with ECG were prepared using a solvent evaporation method. The Double-NPs effectively scavenged reactive oxygen species, promoted macrophage migration, inhibited macrophage apoptosis, and suppressed abnormal proliferation and migration of vascular smooth muscle cells. Furthermore, the Double-NPs actively accumulated in atherosclerotic plaques in ApoE-/- mice fed with a high-fat diet, leading to a reduced plaque area, inflammatory infiltration, and plaque instability. Our findings demonstrate that the newly developed ECG nanopreparation represents an effective and safe nanotherapy for diseases such as atherosclerosis.

IRF5 governs macrophage adventitial infiltration to fuel abdominal aortic aneurysm formation.

Abdominal aortic aneurysm (AAA) is a chronic inflammatory disease characterized by the expansion of the aortic wall. One of the most significant features is the infiltration of macrophages in the adventitia, which drives vasculature remodeling. The role of macrophage-derived interferon regulatory factor 5 (IRF5) in macrophage infiltration and AAA formation remains unknown. RNA sequencing of AAA adventitia identified Irf5 as the top significantly increased transcription factor that is predominantly expressed in macrophages. Global and myeloid cell-specific deficiency of Irf5 reduced AAA progression, with a marked reduction in macrophage infiltration. Further cellular investigations indicated that IRF5 promotes macrophage migration by direct regulation of downstream phosphoinositide 3-kinase γ (PI3Kγ, Pik3cg). Pik3cg ablation hindered AAA progression, and myeloid cell-specific salvage of Pik3cg restored AAA progression and macrophage infiltration derived from Irf5 deficiency. Finally, we found that IRF5 and PI3Kγ expression in the adventitia is significantly increased in patients with AAA. These findings reveal that the IRF5-dependent regulation of PI3Kγ is essential for AAA formation.

TMIC-17. THE ROLE OF ICAM1 IN GLIOBLASTOMA TUMORIGENESIS UNDER HYPOXIC CONDITIONS

Abstract Glioblastoma (GBM) is a deadly brain cancer in adults with limited treatment options. Cell adhesion molecules (CAMs) mediate cell-cell interactions and migration. Intercellular adhesion molecule 1 (ICAM-1) is a CAM expressed by various cell types in solid tumors, including macrophages, tumor and endothelial cells. We previously demonstrated that ICAM-1 expression is linked to shorter overall survival in GBM patients. We observed elevated ICAM-1 levels in hypoxic regions of GBMs. Considering the role of tumor-associated macrophages (TAMs) in GBM tumorigenicity, our objective was to investigate how ICAM-1 expression in TAMs contributes to GBM growth within the hypoxic tumor microenvironment (TME). We employed a comprehensive approach utilizing in vitro and in vivo models, as well as genomic analyses at both bulk and single-cell levels, to elucidate the association between ICAM-1 and TAMs in tumorigenicity. Our findings demonstrated that injecting GBM cells into ICAM-1 knockout mice led to prolonged survival, smaller tumors, reduced macrophage infiltration, and enhanced M1-like polarization of TAMs. Additionally, bone marrow reconstitution experiments confirmed the tumor-promoting role of ICAM-1-expressing TAMs. Cell deconvolution, immunohistochemical, and flow cytometry analyses of mouse tumors supported these findings. Gene set enrichment analysis of differentially expressed genes in xenografted tumors revealed that ICAM-1 presence upregulated key tumorigenic pathways, including epithelial-mesenchymal transition, IL2-STAT5, TNF-α via NFκB, IL6-JAK-STAT3, and RAS/MAPK. In vitro analysis indicated that ICAM-1 promoted macrophage migration and polarization towards M2-like state, which was further augmented by hypoxia-induced ICAM1 expression. Flow cytometry, cytometry by time of flight (cyToF), and single-cell RNA sequencing analysis of human and mouse GBMs revealed elevated ICAM-1 expression in hypoxic TAMs, suggesting the hypoxic microenvironment promotes the tumorigenic functions of TAMs. In conclusion, ICAM1 likely enhances GBM tumorigenesis by promoting TAM migration into the TME. Furthermore, environmental factors such as hypoxia contribute to increased ICAM-1 expression in TAMs, further exacerbating GBM tumorigenicity.

MiR-597-5p inhibits carcinogenesis and macrophage recruitment in colitis-related colorectal cancer via reducing the expression of CXCL5

ABSTRACT Despite being the subject of multiple cancer studies, nothing is known about miR-597-5p’s role in colitis-associated colorectal cancer (CAC). We intend to explore how miR-597-5p influences the growth and development of CAC. In order to construct a CAC model, mice were stimulated with azoxymethane (AOM)/dextran sulfate sodium (DSS). The in situ hybridization (ISH) and quantitative real-time polymerase chain reaction (qRT-PCR) was used for the detection of miR-597-5p expression. The protein expression of CXCL5 was determined by western blotting, immunohistochemistry and enzyme-linked immuno sorbent assay (ELISA). The histologic colitis score and hematoxylin and eosin (HE) staining were used to evaluate degree of damage to colonic tissues. The proportion of macrophages detected in colon tumors was also measured using flow cytometry. The transwell test was employed to assess macrophage migration. It was found that the miR-597-5p and its target CXCL5 had a negative correlation. MiR-597-5p expression was decreased, while CXCL5 expression was raised in CAC tissues. In AOM/DSS-induced mice, miR-597-5p deficiency in intestinal epithelial cells resulted in decreasing colon length as well as increasing tumor numbers and histologic colitis score, which was reversed by CXCL5 inhibition. MiR-597-5p deficiency facilitated macrophage recruitment in AOM/DSS-induced mice and promoted macrophage migration in vitro, which were reversed by CXCL5 inhibition. Deficiency of miR-597-5p aggravated macrophage recruitment and tumorigenesis in a mouse CAC model, suggesting that miR-597-5p agonists may have an anti-inflammatory therapeutic effect in inflammatory bowel diseases and reduce the risk of developing CAC.

GRK2 inhibits Flt-1+ macrophage infiltration and its proangiogenic properties in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease with a complex etiology. Monocyte-derived macrophages (MDMs) infiltration are associated with RA severity. We have reported the deletion of G-protein-coupled receptor kinase 2 (GRK2) reprograms macrophages toward an anti-inflammatory phenotype by recovering G-protein-coupled receptor signaling. However, as more GRK2-interacting proteins were discovered, the GRK2 interactome mechanisms in RA have been understudied. Thus, in the collagen-induced arthritis mouse model, we performed genetic GRK2 deletion using GRK2f/fLyz2-Cre+/− mice. Synovial inflammation and M1 polarization were improved in GRK2f/fLyz2-Cre+/− mice. Supporting experiments with RNA-seq and dual-luciferase reporter assays identified peroxisome proliferator-activated receptor γ (PPARγ) as a new GRK2-interacting protein. We further confirmed that fms-related tyrosine kinase 1 (Flt-1), which promoted macrophage migration to induce angiogenesis, was inhibited by GRK2-PPARγ signaling. Mechanistically, excess GRK2 membrane recruitment in CIA MDMs reduced the activation of PPARγ ligand-binding domain and enhanced Flt-1 transcription. Furthermore, the treatment of mice with GRK2 activity inhibitor resulted in significantly diminished CIA pathology, Flt-1+ macrophages induced-synovial inflammation, and angiogenesis. Altogether, we anticipate to facilitate the elucidation of previously unappreciated details of GRK2-specific intracellular signaling. Targeting GRK2 activity is a viable strategy to inhibit MDMs infiltration, affording a distinct way to control joint inflammation and angiogenesis of RA.

Antigen processing and presentation-related signature-derived BNIP3 is a novel oncogene and immunotherapy determinant in osteosarcoma based on machine learning and in vitro validation.

In recent decades, osteosarcoma has remained the most prevalent kind of malignant tumor. An important and crucial factor in immunotherapy is antigen processing and presentation (APP). The specific functions and pathogenic processes of APP in osteosarcoma have not, however, been studied. Patients with osteosarcoma were divided into groups using APP-related genes. Machine learning was used to further build the APP-related score. Investigated in-depth were the prognostic relevance of the score, mutation features, immunological aspects, and pharmacological prediction performance. Investigations of the prognostic utility, immunological traits, drug prediction effectiveness and immunotherapy prediction of BNIP3 were performed in-depth. Investigations by cell counting kit-8, Transwell and 5-ethynyl-2-deoxyuridine (EdU) demonstrated that BNIP3 is an osteosarcoma tumor accelerator. The osteosarcoma gene BNIP3 may promote macrophage migration. The APP-related score shows potential for clinical use. It was anticipated that more in vitro and in vivo studies would confirm BNIP3's tumorigenic and immunogenic processes in osteosarcoma.

Leucine-Based Pseudo-Proteins (LPPs) as Promising Biomaterials: A Study of Cell-Supporting Properties.

Scaffold-based systems have become essential in biomedical research, providing the possibility of building in vitro models that can better mimic tissue/organic physiology. A relatively new family of biomimetics-pseudo-proteins (PPs)-can therefore be considered especially promising in this context. Three different artificial leucine-based LPP films were tested in vitro as potential scaffolding materials. In vitro experiments were performed using two types of cells: primary mouse skin fibroblasts and a murine monocyte/macrophages cell line, RAW264.7. Cell adhesion and cell spreading were evaluated according to morphological parameters via scanning electron microscopy (SEM), and they were assessed according to actin cytoskeleton distribution, which was studied via confocal laser microscopy. Cell proliferation was evaluated via an MTT assay. Cell migration was studied using time-lapse microscopy. SEM images for both types of cells demonstrated prominent adhesion and perfect cell spreading on all three LPPs. Analyses of actin cytoskeleton organization revealed a high number of focal adhesions and prominent motility-associated structures. A certain stimulation of cell proliferation was detected in the cases of all three LPPs, and two of them promoted macrophage migration. Overall, our data suggest that the LPPs used in the study can be considered potential cell-friendly scaffolding materials.

Proteomics and phosphoproteomics analysis identifies liver immune protein markers in large yellow croakers (Larimichthys crocea) fed a soybean oil-based diet

Dietary fish oil (FO) replacement has led to an inflammatory response in fish species. This study aimed to identify immune-related proteins in the liver tissue of fish fed a FO-based or soybean oil (SO)-based diet. By conducting proteomics and phosphoproteomics analyses, a total of 1601 differentially expressed proteins (DEPs) and 460 differentially abundant phosphorylated proteins (DAPs) were identified, respectively. Enrichment analysis revealed immune-related proteins involved in bacterial infection, pathogen identification, cytokine production, and cell chemotaxis. The mitogen-activated protein kinase (MAPK) pathway exhibited significant alterations in both protein and phosphorylation levels, with several hub DEPs and DAPs associated with MAPK pathway and leukocyte transendothelial migration being notable. In vitro experiments indicated that linolenic acid (LNA), derived from SO, inhibited the expression of NF-E2-related factor 2 (Nrf2), but increased the expression of signaling proteins linked to nuclear factor κB (NF-κB) and MAPK pathways. Transwell assays indicated that treatment of liver cells with LNA promoted macrophage migration. Collectively, the results showed that the SO-based diet upregulated the expression of NF-κB signaling-related proteins and activated the MAPK pathway, promoting immune cell migration. These findings provide novel insights for developing effective solutions to alleviate health problems caused by dietary high levels of SO inclusion.

The chemokine CCL1 facilitates pulmonary fibrosis by promoting macrophage migration and M2 polarization

Macrophage M2 polarization has been identified in the pathogenesis of pulmonary fibrosis (PF), but the mediators that drive the macrophage M2 program in PF need to be clarified. We showed that the expression of AMFR and CCR8, two known receptors of CCL1, was increased in macrophages from lungs of mice with bleomycin (BLM)-induced PF. Deficiency in either AMFR or CCR8 in macrophages protected mice from BLM-induced PF. In vitro experiments revealed that CCL1 recruited macrophages by binding to its classical receptor CCR8 and drove the macrophage M2 phenotype via its interaction with the recently identified receptor AMFR. Mechanistic studies revealed that the CCL1-AMFR interaction enhanced CREB/C/EBPβ signaling to promote the macrophage M2 program. Together, our findings reveal that CCL1 acts as a mediator of macrophage M2 polarization and could be a therapeutic target in PF.

A novel inflammation-related signature for predicting prognosis and characterizing the tumor microenvironment in colorectal cancer.

Inflammation is a critical component of tumor progression, and it modifies the tumor microenvironment by various mechanisms. Here, we explore the effect of the inflammatory response on the tumor microenvironment in colorectal cancer (CRC). A prognostic signature consisting of inflammation-related genes (IRGs) was constructed and verified based on the inflammatory response by bioinformatics analysis. IRG risk model was identified as an independent prognostic factor in CRC, and was related to biological processes of extracellular matrix, cell adhesion and angiogenesis. The IRG risk score predicted the clinical benefit of ipilimumab. Weighted correlation network analysis identified TIMP1 as the hub gene of the inflammatory response in the IRG risk model. Coculture experiments with macrophages and CRC cells revealed that TIMP1 promoted macrophage migration, inhibited the expression of M1 markers (CD11C and CD80), and promoted the expression of M2 markers (ARG1 and CD163). TIMP1 promoted the expression of ICAM1 and CCL2 by activating the ERK1/2 signaling pathway to promote macrophage migration and M2-like polarization. These IRGs in the risk model regulated stromal and immune components in the tumor microenvironment and could serve as potential therapeutic targets in CRC. TIMP1 promoted macrophage migration and meditated macrophage M2 polarization by activating ERK1/2/CLAM1 and CCL2.

Exosomes derived from synovial fibroblasts from patients with rheumatoid arthritis promote macrophage migration that can be suppressed by miR-124-3p

ObjectivesExosomes are potent vehicles for intercellular communication. Rheumatoid arthritis (RA) is a chronic systemic disease of unknown etiology. Local administration of miR-124 precursor to rats with adjuvant-induced arthritis suppresses systemic arthritis and bone destruction. Thus, exosomes may be involved in this disease. We aimed to determine the role of exosomes in the pathology of RA. MethodsFibroblast-like synoviocytes (FLS) were collected from patients with RA and osteoarthritis (OA). miR-124-3p mimic was transfected into the RA FLS (RA miR-124 FLS). Exosomes were collected from the culture medium by ultracentrifugation. Macrophages were produced from THP-1 cells. MicroRNAs in the exosomes were analyzed using real-time PCR. Proteomics analysis was performed using nanoscale liquid chromatography-tandem mass spectrometry. Macrophage migration was evaluated using a Transwell migration assay. SiRNA was used to knockdown proteins of interest. ResultsMicroRNAs in the RA FLS, RA miR-124 FLS, and OA FLS exosomes were similar. Proteomics analysis revealed that pentraxin 3 (PTX3) levels were higher in RA FLS exosomes than in RA miR-124 FLS and OA FLS exosomes, and proteasome 20S subunit beta 5 (PSMB5) levels were lower in RA FLS exosomes than in RA miR-124 FLS and OA FLS exosomes. The RA FLS exosomes promoted and the RA miR-124 FLS exosomes suppressed macrophage migration. PTX3-silenced RA FLS exosomes suppressed and PSMB5-silenced OA FLS exosomes promoted macrophage migration. ConclusionsRA FLS exosomes promote macrophage migration via PTX3 and PSMB5, and miR-124-3p suppresses this migration.

Disruption of SLFN11 Deficiency–Induced CCL2 Signaling and Macrophage M2 Polarization Potentiates Anti–PD-1 Therapy Efficacy in Hepatocellular Carcinoma

The therapeutic effect of immune checkpoint inhibitors (ICIs) is poor in hepatocellular carcinoma (HCC) and varies greatly among individuals. Schlafen (SLFN) family members have important functions in immunity and oncology, but their roles in cancer immunobiology remain unclear. We aimed to investigate the role of the SLFN family in immune responses against HCC. Transcriptome analysis was performed in human HCC tissues with or without response to ICIs. A humanized orthotopic HCC mouse model and a co-culture system were constructed, and cytometry by time-of-flight technology was used to explore the function andmechanism of SLFN11 in the immune context of HCC. SLFN11 was significantly up-regulated in tumors that responded to ICIs. Tumor-specific SLFN11 deficiency increased the infiltration of immunosuppressive macrophages and aggravated HCC progression. HCC cells with SLFN11 knockdown promoted macrophage migration and M2-like polarization in a C-C motif chemokine ligand 2-dependent manner, which in turn elevated their own PD-L1 expression by activating the nuclear factor-κB pathway. Mechanistically, SLFN11 suppressed the Notch pathway and C-C motif chemokine ligand 2 transcription by binding competitively with tripartite motif containing 21 to the RNA recognition motif 2 domain of RBM10, thereby inhibiting tripartite motif containing 21-mediated RBM10 degradation to stabilize RBM10 and promote NUMB exon 9 skipping. Pharmacologic antagonism of C-C motif chemokine receptor 2 potentiated the antitumor effect of anti-PD-1 in humanized mice bearing SLFN11 knockdown tumors. ICIs were more effective in patients with HCC with high serum SLFN11 levels. SLFN11 serves as a critical regulator of microenvironmental immune properties and an effective predictive biomarker of ICIs response in HCC. Blockade of C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 signaling sensitized SLFN11low HCC patients to ICI treatment.

(-)-Epicatechin gallate blocked cellular foam formation in atherosclerosis by modulating CD36 expression in vitro and in vivo.

Green tea is popular worldwide, so its main active ingredients have attracted people's attention. (-)-Epicatechin gallate (ECG) is the main active component of green tea polyphenols, which has good antioxidant activity, but its cardiovascular intervention is unknown. This study established in vitro and in vivo models of ox-LDL-induced macrophages and HFD-induced ApoE-/- mice to study the effects of ECG on atherosclerotic lesions. Firstly, the study confirmed that ECG has a therapeutic effect in different stages of atherosclerotic plaques. Subsequently, the results showed that the ox-LDL-induced release of pro-inflammatory mediators and the expression of the related protein CD86 in macrophages were inhibited by ECG. ECG blocked the formation of cellular foam by downregulating the expression of CD36 and LOX-1 proteins, thereby increasing SOD activity and reducing MDA production in cells. ECG also prevented ox-LDL-induced apoptosis, promoted macrophage migration, and increased plaque stability. The results confirmed that ECG attenuated ox-LDL-induced green fluorescence of ROS in macrophages by inhibiting the expression of related proteins in the NF-κB signaling pathway and activating the HO-1/Nrf2 signaling pathway. These results indicated that ECG has anti-oxidative stress and anti-inflammatory potential, and its molecular mechanism may be related to the inhibition of intracellular NF-κB signaling pathway proteins and activation of the HO-1/Nrf2 signaling pathway.

Depletion of tumor-associated macrophages inhibits lung cancer growth and enhances the antitumor effect of cisplatin.

In lung cancer, tumor-associated macrophages (TAMs), especially M2-like TAMs, represent the main tumor progression components in the tumor microenvironment (TME). Therefore, M2-like TAMs may serve as a therapeutic target. The purpose of this study was to investigate the effect of M2-like TAM depletion in the TME on tumor growth and chemotherapy response in lung cancer. The levels of secreted monocyte chemoattractant protein (MCP-1) and prostaglandin E2 (PGE2) in the supernatants of lung cancer cell lines A549 and LLC were evaluated via ELISA. Cell migration assays were performed to assess the recruitment ability of macrophage cell lines THP-1 and J774-1 cells. Differentiation of macrophages was assessed via flow cytometry. Immunohistochemical staining was performed to visualize M2-like TAMs in transplanted lung cancer in mouse. We used the COX-2 inhibitor nimesulide to inhibit the secretion of MCP-1 and PGE2, which promotes macrophage migration and M2-like differentiation. Nimesulide treatment decreased the secretion of MCP-1 and PGE2 from lung cancer cells. Nimesulide treatment suppressed the migration of macrophages by blocking MCP-1. Lung cancer supernatant induced the differentiation of macrophages toward the M2-like phenotype, and nimesulide treatment inhibited M2-like differentiation by blocking MCP-1 and PGE2. In the lung cancer mouse model, treatment with nimesulide depleted M2-like TAMs in the TME and enhanced the tumor inhibitory effect of cisplatin. Our results indicated that blocking the secretion of MCP-1 and PGE2 from tumor cells depleted M2-like TAMs in the TME and the combination therapy with cisplatin considerably suppressed tumor growth in the LLC mouse model.

Cancer cell intrinsic TIM-3 induces glioblastoma progression

Glioblastoma (GBM) is identified to share common signal pathways between glioma and immune cells. Here, we find that Tcell immunoglobulin domain and mucin domain protein 3 (TIM-3) is one of the most common co-inhibitory immune checkpoints in GBM shared by tumor and non-tumor cells. Glioma cell-intrinsic TIM-3 is involved in not only regulating malignant behaviors of glioma cells but also inducing macrophage migration and transition to anti-inflammatory/pro-tumorigenic phenotype by a TIM-3/interleukin 6 (IL6) signal. In mechanism, as one of the major regulators of IL6, TIM-3 regulates its expression through activating NF-κB. Blocking this feedback loop by Tocilizumab, an IL6R inhibitor, inhibited the above effects and repressed the tumorigenicity of GBM invivo. Our work identifies glioma cell-intrinsic functions of TIM-3/IL6 signal mediating the crosstalk feedback loop between glioma cells and tumor-associated macrophages (TAMs). Blocking this feedback loop may provide a novel therapeutic strategy for GBM.

Abstract 115: Soluble (pro)renin Receptor Contributes To Endotoxin-induced Septic Shock And Aki In Mice

Sepsis associated acute kidney injury (S-AKI) is a life-threating disease with poorly defined mechanisms and limited therapeutic options. Here we examined the role of site-1 protease (S1P)-derived soluble PRR (sPRR) in the S-AKI model induced by lipopolysaccharide (LPS). Male 10-week-old B6129SF1/J mice were pretreated with a S1P inhibitor PF-429242 (PF) at 20 mg/kg/day via minipump and treated with a single s.c. injection of LPS at 10 mg/kg and monitored for 24 hours. By radiotelemetry, LPS induced fall in mean arterial pressure (MAP) (Δ mmHg: -14.98 ± 4.13 in LPS+PF group vs . -23.15 ± 1.82 in LPS+ Vehicle group; n = 6, p < 0.05) and heart rate (HR) (Beats/min: -78.60 ± 20.73 in LPS+PF group vs . -133.35 ± 30.92 in LPS group, n = 6, p < 0.05), which was significantly attenuated by PF treatment. In parallel, renal dysfunction as reflected by the rises in plasma creatinine and BUN along with albuminuria, urinary excretion of NGAL and Kim-1 were all improved. Similar improvement was observed for infiltration of macrophage as assessed by immunofluorescence detection of F4/80 as well as renal mRNA expression of M1 markers such as iNOS, IL-1β, IL-6, and TNFα. The results from the pharmacological study were validated using a recently generated mouse model of mutagenesis of the cleavage site of PRR (termed Mutant mice). LPS-induced hypotensive response, renal dysfunction, the markers of renal injury and inflammation and M1 activation were all improved in Mutant mice as seen with PF treatment. LPS induced a 3.35-fold increase in plasma sPRR which was attenuated by PF or in Mutant mice. By immunofluorescence, LPS-induced PRR expression was largely restricted to renal medullary intercalated dells. In cultured RAW264.7 macrophage cells, recombinant sPRR treatment at 30 nM directly promoted macrophage migration and stimulated mRNA levels of M1 markers, all of which were attenuated by losartan. Taken together, the present study suggests that (1) S1P-derived sPRR contributes to LPS-induced septic shock and AKI, and (2) within the kidney, LPS-induced sPRR originates from intercalated cells and may act in a paracrine manner to activate AT1R on macrophages to induce pro-inflammatory response.

Macrophage polarization is involved in liver fibrosis induced by β 1-adrenoceptor autoantibody.

Accumulating evidence suggests that liver injury can be induced by the over-expression of β 1-adrenergic receptors (β 1-ARs). High titers of autoantibodies specific to β 1-adrenergic receptors (β 1-AA) are detected in the sera of heart failure patients, potentially playing agonist-like roles. However, the role of β 1-AA in liver function has not been characterized. In this study, we collect the sera of primary biliary cholangitis (PBC) patients, a condition which easily develops into liver fibrosis, and analyze the relationship between PBC and β 1-AA. A passive immunization model is established to assess the effect of β 1-AA on the liver. Subsequently, the effect of β 1-AA on macrophages is investigated in vitro. Results show that PBC patients have a high titer and ratio of β 1-AA, compared to controls. Liver injury and fibrosis are induced by β 1-AA. In vitro experiments with ROS probe demonstrate that β 1-AA induces macrophages to produce ROS and secrete TNFα. These effects can be partially reversed by metoprolol, a blocker for β 1-AR. Results from the transwell and phagocytosis assays show that β 1-AA promotes macrophage migration and phagocytosis. FCM tests suggest that β 1-AA induces the alteration of M1 rather than M2 markers in macrophages. Finally, the Annexin V/PI assay indicates that macrophage culture supernatants stimulated by β 1-AA cause hepatocyte apoptosis. Overall, these results suggest that β 1-AA is involved in PBC. The β 1-AA-induced activation, phagocytosis and phenotypic modification of macrophages may play an important role in the development of hepatic fibrosis and injury.

Mesenchymal stem cells pretreated with proinflammatory cytokines accelerate skin wound healing by promoting macrophages migration and M2 polarization.

IntroductionNumerous studies have shown that mesenchymal stem cells (MSCs) promote cutaneous wound healing via paracrine signaling. Our previous study found that the secretome of MSCs was significantly amplified by treatment with IFN-γ and TNF-α (IT). It has been known that macrophages are involved in the initiation and termination of inflammation, secretion of growth factors, phagocytosis, cell proliferation and collagen deposition in wound, which is the key factor during wound healing. In the present study, we used a unique supernatant of MSCs from human umbilical cord-derived MSCs (UC-MSCs) pretreated with IT, designated S-IT MSCs, to explore whether S-IT MSCs have a better effect on improving wound healing by improving the biological function of macrophages than the control supernatant of MSCs (S-MSCs).MethodsIn the present study, we used a unique supernatant of MSCs pretreated with IT subcutaneously injected into a mice total skin excision. We evaluated the effect of S-IT MSCs on wound healing and the quality of wound repair via promoting macrophages migration and M2 polarization in vivo. In addition, the effect of S-IT MSCs on macrophages migration, converting toward M2 phenotype and phagocytosis were also investigated in vitro.ResultsIndeed, S-IT MSCs were found to be more potent in promoting macrophage migration, M2 polarization, phagocytosis, and promoting wound closure than S-MSCs during the wound repair. High levels of CCL2 and IL-6 were found in S-IT MSCs, which indicated that the optimization of macrophage function by S-IT MSCs may be achieved through their high expression of CCL2 and IL-6.ConclusionsOur results suggest that the beneficial paracrine effect of MSCs on wound healing can be amplified by pretreatment with IT, which may represent a new strategy for optimizing the therapeutic effect of MSCs on wound healing.