Macrophage-derived Exosomes Research Articles

M2 macrophage-derived exosomes carry miR-142-3p to restore the differentiation balance of irradiatedBMMSCs by targeting TGF-β1.

Radiotherapy is essential to cancer treatment, while it inevitably injures surrounding normal tissues, and bone tissue is one of the most common sites prone to irradiation. Bone marrow mesenchymal stem cells (BMMSCs) are sensitive to irradiation and the irradiated dysfunction of BMMSCs may be closely related to irradiation-induced bone damage. Macropahges play important role in regulating stem cell function, bone metabolic balance and irradiation response, but the effects of macrophages on irradiated BMMSCs are still unclear. This study aimed to investigate the role of macrophages and macrophage-derived exosomes in restoring irradiated BMMSCs function. The effects of macrophage conditioned medium (CM) and macrophage-derived exosomes on osteogenic and fibrogenic differentiation capacities of irradiated BMMSCs were detected. The key microribonucleic acids (miRNAs) and targeted proteins in exosomes were also determined. The results showed that irradiation significantly inhibited the proliferation of BMMSCs, and caused differentiation imbalance of BMMSCs, with decreased osteogenic differentiation and increased fibrogenic differentiation. M2 macrophage-derived exosomes (M2D-exos) inhibited the fibrogenic differentiation and promoted the osteogenic differentiation of irradiated BMMSCs. We identified that miR-142-3p was significantly overexpressed in M2D-exos and irradiated BMMSCs treated with M2D-exos. After inhibition of miR-142-3p in M2 macrophage, the effects of M2D-exos on irradiated BMMSCs differentiation were eliminated. Furthermore, transforming growth factor beta 1 (TGF-β1), as a direct target of miR-142-3p, was significantly decreased in irradiated BMMSCs treated with M2D-exos. This study indicated that M2D-exos could carry miR-142-3p to restore the differentiation balance of irradiated BMMSCs by targeting TGF-β1. These findings pave a new way for promising and cell-free method to treat irradiation-induced bone damage.

M2 macrophage-derived exosomes promote diabetic fracture healing by acting as an immunomodulator

Diabetes mellitus is a chronically inflamed disease that predisposes to delayed fracture healing. Macrophages play a key role in the process of fracture healing by undergoing polarization into either M1 or M2 subtypes, which respectively exhibit pro-inflammatory or anti-inflammatory functions. Therefore, modulation of macrophage polarization to the M2 subtype is beneficial for fracture healing. Exosomes perform an important role in improving the osteoimmune microenvironment due to their extremely low immunogenicity and high bioactivity. In this study, we extracted the M2-exosomes and used them to intervene the bone repair in diabetic fractures. The results showed that M2-exosomes significantly modulate the osteoimmune microenvironment by decreasing the proportion of M1 macrophages, thereby accelerating diabetic fracture healing. We further confirmed that M2-exosomes induced the conversion of M1 macrophages into M2 macrophages by stimulating the PI3K/AKT pathway. Our study offers a fresh perspective and a potential therapeutic approach for M2-exosomes to improve diabetic fracture healing.

M1 macrophage-derived exosomes containing miR-150 inhibit glioma progression by targeting MMP16

A large amount of clinical and experimental evidence indicates that M1 macrophages can inhibit tumor progression and expansion; however, the molecular mechanism by which macrophage-derived exosomes inhibit the proliferation of glioblastoma cells has not yet been elucidated. Here, we used M1 macrophage exosomes encapsulating microRNAs to inhibit the proliferation of glioma cells. Exosomes derived from M1 macrophages exhibited high expression levels of miR-150, and the inhibition of glioma cell proliferation mediated by exosomes derived from M1 macrophages was dependent on this microRNA. Mechanistically, miR-150 is transferred to glioblastoma cells through M1 macrophages and binds to MMP16, downregulating its expression and inhibiting glioma progression. Overall, these findings indicate that M1 macrophage-derived exosomes carrying miR-150 inhibit the proliferation of glioblastoma cells through targeted binding to MMP16. This dynamic mutual influence between glioblastoma cells and M1 macrophages provides new opportunities for the treatment of glioma.

M2 macrophage-derived exosomes suppress tumor intrinsic immunogenicity to confer immunotherapy resistance

ABSTRACT T-cell-based immune checkpoint blockade therapy (ICB) can be undermined by local immunosuppressive M2-like tumor-associated macrophages (TAMs). However, modulating macrophages has proved difficult as the molecular and functional features of M2-TAMs on tumor growth are still uncertain. Here we reported that immunosuppressive M2 macrophages render cancer cells resistant to CD8+ T-cell-dependent tumor-killing refractory ICB efficacy by secreting exosomes. Proteomics and functional studies revealed that M2 macrophage-derived exosome (M2-exo) transmitted apolipoprotein E (ApoE) to cancer cells conferring ICB resistance by downregulated MHC-I expression curbing tumor intrinsic immunogenicity. Mechanistically, M2 exosomal ApoE diminished the tumor-intrinsic ATPase activity of binding immunoglobulin protein (BiP) to decrease tumor MHC-I expression. Sensitizing ICB efficacy can be achieved by the administration of ApoE ligand, EZ-482, enhancing ATPase activity of BiP to boost tumor-intrinsic immunogenicity. Therefore, ApoE may serve as a predictor and a potential therapeutic target for ICB resistance in M2-TAMs-enriched cancer patients. Collectively, our findings signify that the exosome-mediated transfer of functional ApoE from M2 macrophages to the tumor cells confers ICB resistance. Our findings also provide a preclinical rationale for treating M2-enriched tumors with ApoE ligand, EZ-482, to restore sensitivity to ICB immunotherapy.

Exosomal miR-663b from "M1" macrophages promotes pulmonary artery vascular smooth muscle cell dysfunction through inhibiting the AMPK/Sirt1 axis.

Inflammatory mediators from macrophages are proven to be involved in pulmonary vascular remodeling in pulmonary hypertension (PH). Here, this study intends to explore the mechanism of "M1" macrophage-derived exosomal miR-663b in pulmonary artery smooth muscle cells (PASMCs) dysfunctions and pulmonary hypertension. Hypoxia-treated PASMCs were utilized for constructing an in-vitro pulmonary hypertension model. THP-1 cells were treated with PMA (320 nM) and LPS (10 μg/mL) + IFN-γ (20 ng/ml) for eliciting macrophage "M1" polarization. Exosomes derived from "M1" macrophages were isolated and added into PASMCs. The proliferation, inflammation, oxidative stress, and migration of PASMCs were evaluated. RT-PCR or Western blot examined the levels of miR-663b and the AMPK/Sirt1 pathway. Dual luciferase activity assay and RNA pull-down assay were carried out for confirming the targeted association between miR-663b and AMPK. An in-vivo PH model was built. Macrophage-derived exosomes with miR-663b inhibition were used for treating the rats, and alterations of pulmonary histopathology were monitored. miR-663b was obviously up-regulated in hypoxia-elicited PASMCs and M1 macrophages. miR-663b overexpression boosted hypoxia-induced proliferation, inflammation, oxidative stress, and migration in PASMCs, whereas miR-663b low expression resulted in the opposite situation. AMPK was identified as a target of miR-663b, and miR-663b overexpression curbed the AMPK/Sirt1 pathway. AMPK activation ameliorated the damaging impact of miR-663b overexpression and "M1" macrophage exosomes on PASMCs. In vivo, "M1" macrophage exosomes with miR-663b low expression alleviated pulmonary vascular remodeling in pulmonary hypertension rats. Exosomal miR-663b from "M1" macrophage facilitates PASMC dysfunctions and PH development by dampening the AMPK/Sirt1 axis.

Macrophage-inherited exosome excise tumor immunosuppression to expedite immune-activated ferroptosis

BackgroundImmunosuppressive tumor microenvironment (ITM) remains an obstacle that jeopardizes clinical immunotherapy.MethodsTo address this concern, we have engineered an exosome inherited from M1-pheototype macrophages, which thereby retain functions and ingredients of...

Macrophage-derived exosome promotes regulatory T cell differentiation in malignant pleural effusion.

Tumor-associated macrophages are one of the key components of the tumor microenvironment. The immunomodulatory activity and function of macrophages in malignant pleural effusion (MPE), a special tumor metastasis microenvironment, have not been clearly defined. MPE-based single-cell RNA sequencing data was used to characterize macrophages. Subsequently, the regulatory effect of macrophages and their secreted exosomes on T cells was verified by experiments. Next, miRNA microarray was used to analyze differentially expressed miRNAs in MPE and benign pleural effusion, and data from The Cancer Genome Atlas (TCGA) was used to evaluate the correlation between miRNAs and patient survival. Single-cell RNA sequencing data showed macrophages were mainly M2 polarized in MPE and had higher exosome secretion function compared with those in blood. We found that exosomes released from macrophages could promote the differentiation of naïve T cells into Treg cells in MPE. We detected differential expression miRNAs in macrophage-derived exosomes between MPE and benign pleural effusion by miRNA microarray and found that miR-4443 was significantly overexpressed in MPE exosomes. Gene functional enrichment analysis showed that the target genes of miR-4443 were involved in the regulation of protein kinase B signaling and lipid biosynthetic process. Taken together, these results reveal that exosomes mediate the intercellular communication between macrophages and T cells, yielding an immunosuppressive environment for MPE. miR-4443 expressed by macrophages, but not total miR-4443, might serve as a prognostic marker in patients with metastatic lung cancer.

LRRC75A-AS1 delivered by M2 macrophage exosomes promotes cervical cancer progression via enhancing SIX1 expression.

We aimed to investigate potential roles of LRRC75A-AS1 delivered by M2 macrophage exosomes in inducing cervical cancer progression. We demonstrated LRRC75A-AS1 was highly expressed in exosomes from M2 macrophages which could be absorbed by Hela cells. M2 macrophage-derived exosomes promoted Hela cell proliferation, migration, invasion, and EMT process by delivering LRRC75A-AS1. LRRC75A-AS1 directly targeted and suppressed miR-429 in Hela cells. The regulation of cell functions by exosomes from LRRC75A-AS1-overexpressing M2 macrophages was abrogated by miR-429 mimics. miR-429 directly targeted and repressed SIX1 expression. SIX1 overexpression alleviated the modulation of cellular functions and STAT3/MMP-9 signaling by miR-429 mimics. Also, miR-429 overexpression or SIX1 silence repressed tumor formation and metastasis in nude mice, which was mitigated by exosomes from LRRC75A-AS1-overexpressing M2 macrophages. In conclusion, LRRC75A-AS1 delivered by M2 macrophage exosomes repressed miR-429 to elevate SIX1 expression and promote cervical cancer progression through activating the STAT3/MMP-9 axis.

IL-33 Downregulates Hepatic Carboxylesterase 1 in Acute Liver Injury via Macrophage-derived Exosomal miR-27b-3p.

We previously reported that carboxylesterase 1 (CES1) expression was suppressed following liver injury. The study aimed to explore the role of interleukin (IL)-33 in liver injury and examine the mechanism by which IL-33 regulates CES1. IL-33 and CES1 levels were determined in the livers of patients and lipopolysaccharide (LPS)-, acetaminophen (APAP)-treated mice. We constructed IL-33 and ST2 knockout (KO) mice. ST2-enriched immune cells in livers were screened to identify the responsible cells. Macrophage-derived exosome (MDE) activity was tested by adding exosome inhibitors. Micro-RNAs (miRs) were extracted from control and IL-33-stimulated MDEs (IL-33-MDEs) and subjected miR sequencing (miR-Seq). Candidate miR was tested in vitro and in vivo and its binding of a target gene was assessed by luciferase reporter assays. Lentivirus-vector cellular transfection and transcript silencing were used to examine pathways mediating IL-33 suppression of miR-27b-3p. Patient liver IL-33 and CES1 expression levels were inversely correlated. CES1 downregulation in liver injury was rescued in both IL-33-deficient and ST2 KO mice. Macrophages were shown to be responsible for IL-33 effects. IL-33-MDEs reduced CES1 levels in hepatocytes. Exosomal miR-Seq and qRT-PCR demonstrated increased miR-27b-3p levels in IL-33-MDEs; miR-27b-3p was implicated in Nrf2 targeting. IL-33 inhibition of miR-27b-3p was found to be GATA3-dependent. IL-33-ST2-GATA3 pathway signaling increases miR-27b-3p content in MDEs, which upon being internalized by hepatocytes reduce CES1 expression by inhibiting Nrf2. The elucidation of this mechanism in this study contributes to a better understanding of CES1 dysregulation in liver injury.

Mechanical force induces macrophage-derived exosomal UCHL3 promoting bone marrow mesenchymal stem cell osteogenesis by targeting SMAD1

BackgroundOrthodontic tooth movement (OTM), a process of alveolar bone remodelling, is induced by mechanical force and regulated by local inflammation. Bone marrow-derived mesenchymal stem cells (BMSCs) play a fundamental role in osteogenesis during OTM. Macrophages are mechanosensitive cells that can regulate local inflammatory microenvironment and promote BMSCs osteogenesis by secreting diverse mediators. However, whether and how mechanical force regulates osteogenesis during OTM via macrophage-derived exosomes remains elusive.ResultsMechanical stimulation (MS) promoted bone marrow-derived macrophage (BMDM)-mediated BMSCs osteogenesis. Importantly, when exosomes from mechanically stimulated BMDMs (MS-BMDM-EXOs) were blocked, the pro-osteogenic effect was suppressed. Additionally, compared with exosomes derived from BMDMs (BMDM-EXOs), MS-BMDM-EXOs exhibited a stronger ability to enhance BMSCs osteogenesis. At in vivo, mechanical force-induced alveolar bone formation was impaired during OTM when exosomes were blocked, and MS-BMDM-EXOs were more effective in promoting alveolar bone formation than BMDM-EXOs. Further proteomic analysis revealed that ubiquitin carboxyl-terminal hydrolase isozyme L3 (UCHL3) was enriched in MS-BMDM-EXOs compared with BMDM-EXOs. We went on to show that BMSCs osteogenesis and mechanical force-induced bone formation were impaired when UCHL3 was inhibited. Furthermore, mothers against decapentaplegic homologue 1 (SMAD1) was identified as the target protein of UCHL3. At the mechanistic level, we showed that SMAD1 interacted with UCHL3 in BMSCs and was downregulated when UCHL3 was suppressed. Consistently, overexpression of SMAD1 rescued the adverse effect of inhibiting UCHL3 on BMSCs osteogenesis.ConclusionsThis study suggests that mechanical force-induced macrophage-derived exosomal UCHL3 promotes BMSCs osteogenesis by targeting SMAD1, thereby promoting alveolar bone formation during OTM.Graphical

Macrophage-derived exosomes mediate glomerular endothelial cell dysfunction in sepsis-associated acute kidney injury

BackgroundSepsis-associated AKI has been shown to be related to sepsis mortality. Macrophage activation and endothelial cell damage are involved in the progression of sepsis-associated AKI, but the specific mechanisms are still unclear.MethodsIn vitro experiments, exosomes extracted from lipopolysaccharide (LPS) -stimulated macrophages were co-incubated with rat glomerular endothelial cells (RGECs) and then detected the injury markers of RGECs. Acid sphingomyelinase (ASM) inhibitor amitriptyline were used to investigate the role of ASM. In vivo experiment, exosomes produced by LPS-stimulated macrophages were injected into mice through tail vein to further explore the role of macrophage-derived exosomes. Moreover, ASM knockout mice were used to verify the mechanism.ResultIn vitro, the secretion of macrophage exosomes increased upon the stimulation with LPS. Notably, macrophage-derived exosomes can cause glomerular endothelial cell dysfunction. In vivo, macrophage infiltration and exosome secretion in glomeruli of the LPS-induced AKI group increased. The exosomes produced by LPS-stimulated macrophages were injected into mice, which also led to the injury of renal endothelial cells. In addition, in the LPS-induced AKI mouse model, compared with wild-type mice, the secretion of exosomes in glomeruli of ASM gene knockout mice and the injury of endothelial cells were reduced.ConclusionOur study shows that ASM regulates the secretion of macrophage exosomes, leading to endothelial cell injury, which may be a therapeutic target in sepsis-associated AKI.

Long Non-Coding RNAs Within Macrophage-Derived Exosomes Promote BMSC Osteogenesis in a Bone Fracture Rat Model.

To investigate the effect of macrophage exosomal long non-coding (lnc)RNAs on bone mesenchymal stem cell (BMSC) osteogenesis and the associated mechanism. Rat BMSCs and spleen macrophages were co-cultured with serum derived from the fracture microenvironment of rat tibia. BMSC osteogenesis was evaluated using Alizarin red staining and the expression of BMP-2, RUNX2, OPN, and OC mRNA. BMSC osteogenesis was evaluated after co-culture with macrophages stimulated using hypoxic conditions or colony-stimulating factor (CSF). The uptake of macrophage-derived exosomes by BMSCs was evaluated using the exosome uptake assay. High-throughput sequencing and bioinformatics analyses were performed to identify key lncRNAs in the macrophage exosomes. The effect of lncRNA expression levels on BMSC osteogenesis was also assessed using a lncRNA overexpression plasmid and siRNA technology. M1 and M2 macrophages were distinguished using flow cytometry and the key exosomal lncRNA was detected by in situ hybridization. In the fracture microenvironment, macrophages (stimulated using either hypoxia or CSF) significantly increased the osteogenic ability of BMSCs. We showed that BMSCs assimilated macrophage-derived vesicles and that the inhibition of exosomal secretion significantly attenuated the macrophage-mediated induction of BMSC osteogenesis. The hypoxia condition led to the up-regulation of 310 lncRNAs and the down-regulation of 575 lncRNAs in macrophage exosomes, while CSF stimulation caused the up-regulation of 557 lncRNAs and the down-regulation of 407 lncRNAs. In total, 108 lncRNAs were co-up-regulated and 326 lncRNAs were co-down-regulated under both conditions. We eventually identified LOC103691165 as a key lncRNA that promoted BMSC osteogenesis and was expressed at similar levels in both M1 and M2 macrophages. In the fracture microenvironment, M1 and M2 macrophages promoted BMSC osteogenesis by secreting exosomes containing LOC103691165.

Gram-negative bacterial infection causes aggravated innate immune response in sepsis: Studies from clinical samples and cellular models

Bacterial infection is the most common cause for sepsis. The purpose of this study was to evaluate the impact of different bacterial infection on sepsis based on human samples and cellular experiments. Physiological indexes and prognostic information of 121 sepsis patients were analysed based on whether they had a gram-positive or gram-negative bacterial infection. Moreover, murine RAW264.7 macrophages were treated with lipopolysaccharide (LPS) or peptidoglycan (PG) to simulate infection with gram-negative or gram-positive bacteria in sepsis, respectively. Exosomes derived from the macrophages were extracted for transcriptome sequencing. In patients with sepsis, most gram-positive bacterial infections were Staphylococcus aureus, and gram-negative infections were Escherichia coli. Gram-negative bacterial infection was significantly associated with high neutrophil and interleukin (IL)-6 levels in blood and shorter prothrombin (PT) and activated partial thromboplastin time (APTT). Intriguingly, the survival prognosis of sepsis patients was not affected by the type of bacterial infection, but it was significantly related to fibrinogen. Protein transcriptome sequencing of the macrophage-derived exosomes showed that differentially expressed proteins were significantly enriched in megakaryocyte differentiation, leukocyte and lymphocyte-mediated immunity, and complement and coagulation cascade pathways. The complement and coagulation-related proteins were significantly upregulated after LPS induction, which explained the shortened PT and APTT in gram-negative bacterial sepsis. Bacterial infection did not affect mortality in sepsis but did alter the host response. The immune disorder induced by gram-negative infection was more severe than that produced by gram-positive infection. This study provides references for the rapid identification and molecular research of different bacterial infections in sepsis.

Escherichia coli-Derived Outer Membrane Vesicles Relay Inflammatory Responses to Macrophage-Derived Exosomes.

Extracellular vesicles are considered to be an inflammatory factor in several acute and chronic inflammatory diseases. The present study shows that exosomes from macrophages (Mφ) infected with live Escherichia coli induced secretion of proinflammatory factors by uninfected Mφ. Inflammatory responses induced by exosomes derived from Mφ infected with heat-inactivated E. coli or lipopolysaccharide were significantly weaker than those elicited by outer membrane vesicles (OMVs) released from live E. coli. Proteome analysis of exosomes from Mφ infected with live or heat-inactivated E. coli revealed that E. coli proteins OmpA, GroL1, DegP, CirA, and FepA are candidate triggers of exosome-mediated inflammatory responses. OMVs from a cirA-deleted strain suppressed exosome-mediated inflammatory responses by uninfected Mφ. The C terminus of the CirA protein (residues 158 to 633), which was relayed from E. coli-derived OMV to Mφ-derived exosomes, promoted exosome-mediated inflammatory responses by uninfected Mφ. These results suggest an alternative mechanism by which extracellular vesicles from E. coli OMV-elicited Mφ transmit proinflammatory responses to uninfected Mφ. IMPORTANCE Recently, extracellular membrane vesicles (EVs) were regarded as drivers that carry cargo such as proteins, lipids, metabolites, RNA, and DNA for intracellular signaling transduction. Mammalian cells release various types of EVs, including microvesicles shed from the plasma membrane, exosomes from endosomes, apoptotic bodies, and others. EVs have been reported to mediate inflammatory signals between mammalian cells. In addition, bacteria are also known to release EVs to carry various bacterial factors. In this study, we show that bacterial EVs lead host mammalian cells to release stimulatory EVs that enhance inflammatory responses. Our results provide a novel example that bacterial EVs transduce biological signals to mammalian EVs.

Phillygenin inhibited M1 macrophage polarization and reduced hepatic stellate cell activation by inhibiting macrophage exosomal miR-125b-5p

Liver fibrosis (LF) is an important stage in chronic liver disease development, characterized by hepatic stellate cell (HSC) activation and excessive extracellular matrix deposition. Phillygenin (PHI), an active component in the traditional Chinese medicine Forsythiae Fructus with a significant anti-inflammatory effect, has been proved to inhibit HSC activation. Macrophages can polarize to pro-inflammatory M1 phenotype and anti-inflammatory M2 phenotype, participating in LF development. Currently, Forsythiae Fructus and its many components have been proved to inhibit the inflammatory activation of macrophages. However, there is no direct evidence that PHI can regulate macrophage polarization, and the relationship between macrophage polarization and the anti-LF effect of PHI has not been studied. In this study, we found that PHI inhibited the co-expression of CD80 and CD86, and inhibited the mRNA expression and protein secretion of related inflammatory cytokines in RAW264.7 cells. For mechanism, PHI was found to inhibit the JAK1/JAK2-STAT1 and Notch1 signaling pathways. Subsequently, mHSCs were co-cultured with the conditioned media or exosomes from macrophages with different treatments. It was found that the conditioned media and exosomes from PHI-treated macrophages inhibited the expression of MMP2, TIMP1, TGF-β, α-SMA, COL1 and NF-κB in mHSCs. Moreover, through bioinformatic analysis and cell transfection, we confirmed that PHI reduced HSC activation by inhibiting the overexpression of miR-125b-5p in M1 macrophage-derived exosomes and restoring Stard13 expression in mHSCs. On the whole, PHI could inhibit M1 macrophage polarization by suppressing the JAK1/JAK2-STAT1 and Notch1 signaling pathways, and reduce HSC activation by inhibiting macrophage exosomal miR-125b-5p targeting Stard13. Data AvailabilityThe raw data supporting the conclusions of this study are available in the article/Supplementary figures, and can be obtained from the first or corresponding author.

M2 macrophage-derived exosomal miR-193b-3p promotes progression and glutamine uptake of pancreatic cancer by targeting TRIM62

BackgroundPancreatic cancer (PC) is a highly lethal malignancy that requires effective novel therapies. M2 macrophages are abundant in the PC microenvironment and promote cancer progression. Exosomes are emerging mediators of the crosstalk between cancer cells and the microenvironment. This study was conducted to explore the role of M2 macrophage-derived exosomes in PC.MethodsExosomes derived from M2 macrophages were extracted. miR-193b-3p and TRIM62 were overexpressed or silenced to examine their function in PC. Luminescence assays were used to investigate the interaction between miR-193b-3p and TRIM62. Cell proliferation was examined by EdU staining. Would healing and transwell assays were applied to evaluate cell migration and invasion. Co-immunoprecipitation was used to assess the interaction between TRIM62 and c-Myc. Gene and protein expressions were analyzed by quantitative RT-PCR and immunoblotting, respectively.ResultsM2 macrophage-derived exosomal miR-193b-3p promoted the proliferation, migration, invasion, and glutamine uptake of SW1990 cells. Mechanism study revealed that TRIM62 is a target of miR-193b-3p. TRIM62 inhibited the proliferation, migration, invasion, and glutamine uptake of SW1990 cells by promoting c-Myc ubiquitination. Our data also suggested that TRIM62 expression negatively correlated with miR-193b-3p and c-Myc expression. High-expression of miR-193b-3p and c-Myc predicts poor prognosis, whereas low-expression of TRIM62 predicts poor prognosis in patients with PC.ConclusionM2 macrophage-derived exosomal miR-193b-3p enhances the proliferation, migration, invasion, and glutamine uptake of PC cells by targeting TRIM62, resulting in the decrease of c-Myc ubiquitination. This study not only reveals the mechanism underlying the crosstalk between M2 macrophages and PC cells but also suggests a promising therapeutic target for PC.

High-Phosphate-Stimulated Macrophage-Derived Exosomes Promote Vascular Calcification via let-7b-5p/TGFBR1 Axis in Chronic Kidney Disease.

Although macrophage infiltration has been proven to increase calcified artery media in chronic kidney disease (CKD) patients, the mechanism by which macrophages are involved in vascular calcification (VC) progression remains unclear. Taking advantage of miRNA-seq, RNA-seq, dual-luciferase reporter assay, qRT-PCR, and arteries from CKD patients as well as CKD mouse models, we identified that high-phosphate-stimulated macrophage-derived exosomes (Mexo-P) suppressed let-7b-5p expression in VSMCs, which further upregulated TGFBR1. Moreover, gain-and-loss-of-function assays were used to determine the regulatory effects and downstream mechanism of let-7b-5p and TGFBR1 on VC. Mechanically, Mexo-P induced VSMC TGFBR1 upregulation by suppressing let-7b-5p, which further amplifies SMAD3/RUNX2 signaling and thereby contributes to VC. Our findings indicate that macrophage-derived exosomes promote CKD-associated VC through the let-7b-5p/TGFBR1 axis in high-phosphate conditions. Our study provides insight into macrophages associated with VC, which might be potential therapeutical targets for VC.

Comprehensive analysis of M2 macrophage-derived exosomes facilitating osteogenic differentiation of human periodontal ligament stem cells

BackgroundThe role of periodontal ligament stem cells (PDLSCs) and macrophage polarization in periodontal tissue regeneration and bone remodeling during orthodontic tooth movement (OTM) has been well documented. Nevertheless, the interactions between macrophages and PDLSCs in OTM remain to be investigated. Consequently, the present study was proposed to explore the effect of different polarization states of macrophages on the osteogenic differentiation of PDLSCs.MethodsAfter M0, M1 and M2 macrophage-derived exosomes (M0-exo, M1-exo and M2-exo) treatment of primary cultured human PDLSCs, respectively, mineralized nodules were observed by Alizarin red S staining, and the expression of ALP and OCN mRNA and protein were detected by RT-qPCR and Western blotting, correspondingly. Identification of differentially expressed microRNAs (DE-miRNA) in M0-exo and M2-exo by miRNA microarray, and GO and KEGG enrichment analysis of DE-miRNA targets, and construction of protein–protein interaction networks.ResultsM2-exo augmented mineralized nodule formation and upregulated ALP and OCN expression in PDLSCs, while M0-exo had no significant effect. Compared to M0-exo, a total of 52 DE-miRNAs were identified in M2-exo. The expression of hsa-miR-6507-3p, hsa-miR-4731-3p, hsa-miR-4728-3p, hsa-miR-3614-5p and hsa-miR-6785-3p was significantly down-regulated, and the expression of hsa-miR-6085, hsa-miR-4800-5p, hsa-miR-4778-5p, hsa-miR-6780b-5p and hsa-miR-1227-5p was significantly up-regulated in M2-exo compared to M0-exo. GO and KEGG enrichment analysis revealed that the downstream targets of DE-miRNAs were mainly involved in the differentiation and migration of multiple cells.ConclusionsIn summary, we have indicated for the first time that M2-exo can promote osteogenic differentiation of human PDLSCs, and have revealed the functions and pathways involved in the DE-miRNAs of M0-exo and M2-exo and their downstream targets.

M2-like macrophage-derived exosomes facilitate metastasis in non-small-cell lung cancer by delivering integrin αVβ3.

Metastasis is the most prevalent cause of cancer deaths, and immunological components of the tumor microenvironment, especially tumor-associated macrophages (TAMs), play a vital role in cancer metastasis. However, the underlying mechanisms of TAMs on non-small-cell lung cancer (NSCLC) metastasis remain largely unexplored. Herein, we demonstrated that M2-like TAMs facilitate the migration and invasion of cancer cells in vitro and in vivo through intercellular delivery of M2-like macrophage-derived exosomes (M2-exos). Importantly, we found that M2-exos had considerably higher levels of integrin (ITG) αV and β3. The impact of M2-like macrophage-mediated invasion and migration of NSCLC cells was clearly decreased when ITG αVβ3 was blocked. Mechanistically, exosomal ITG αVβ3 produced from M2-like macrophages successfully triggered the focal adhesion kinase signaling pathway in recipient cells, boosting the migratory and invasive abilities of NSCLC cells. Clinically, we found that metastatic NSCLC patients had greater ITG αV and β3 expression, which was associated with a worse prognosis. This study reveals a novel mechanism by which M2-exos significantly increased NSCLC cell migration and invasion by delivering integrin αVβ3. Exosomal ITG αVβ3 can be used as a potential prognostic marker, and blocking ITG αVβ3 could be a viable treatment option for preventing tumor metastasis.

Monophosphoryl lipid A ameliorates radiation-induced lung injury by promoting the polarization of macrophages to the M1 phenotype

BackgroundRadiation-induced lung injury (RILI) often occurs during clinical chest radiotherapy and acute irradiation from accidental nuclear leakage. This study explored the role of monophosphoryl lipid A (MPLA) in RILI.Materials and MethodsThe entire thoracic cavity of C57BL/6N mice was irradiated at 20 Gy with or without pre-intragastric administration of MPLA. HE staining, Masson trichrome staining, and TUNEL assay were used to assess lung tissue injury after treatment. The effect of irradiation on the proliferation of MLE-12 cells was analyzed using the Clonogenic assay. The effect of MPLA on the apoptosis of MLE-12 cells was analyzed using flow cytometry. Expression of γ-H2AX and epithelial-mesenchymal transition (EMT) markers in MLE-12 cells was detected by immunofluorescence and Western blot, respectively.ResultsMPLA attenuated early pneumonitis and late pulmonary fibrosis after thoracic irradiation and reversed radiation-induced EMT in C57 mice. MPLA further promoted proliferation and inhibited apoptosis of irradiated MLE-12 cells in vitro. Mechanistically, the radioprotective effect of MPLA was mediated by exosomes secreted by stimulated macrophages. Macrophage-derived exosomes modulated DNA damage in MLE-12 cells after irradiation. MPLA promoted the polarization of RAW 264.7 cells to the M1 phenotype. The exosomes secreted by M1 macrophages suppressed EMT in MLE-12 cells after irradiation.ConclusionMPLA is a novel treatment strategy for RILI. Exosomes derived from macrophages are key to the radioprotective role of MPLA in RILI.