Macrophage Receptor Research Articles

Atg6 promotes organismal health by suppression of cell stress and inflammation.

Autophagy targets cytoplasmic materials for degradation, and influences cell health. Alterations in Atg6/Beclin-1, a key regulator of autophagy, are associated with multiple diseases. While the role of Atg6 in autophagy regulation is heavily studied, the role of Atg6 in organism health and disease progression remains poorly understood. Here, we discover that loss of Atg6 in Drosophila results in various alterations to stress, metabolic and immune signaling pathways. We find that the increased levels of circulating blood cells and tumor-like masses in atg6 mutants vary depending on tissue-specific function of Atg6, with contributions from intestine and hematopoietic cells. These phenotypes are suppressed by decreased function of macrophage and inflammatory response receptors crq and drpr. Thus, these findings provide a basis for understanding how Atg6 systemically regulates cell health within multiple organs, and highlight the importance of Atg6 in inflammation to organismal health.

Selective Reprogramming of Peritoneal Macrophages by IFN-γ During Acute Toxoplasma gondii Infection

Abstract Host resistance to intracellular pathogens is dependent on the pleiotropic cytokine interferon gamma (IFN-γ) which activates myeloid cells, such as macrophages, and results in pathogen clearance. Macrophages safeguard most regions of the body participating in tissue homeostasis, disease surveillance, pathogen elimination, and resolution of inflammation. The peritoneal cavity is patrolled by two unique subsets of resident macrophages: monocyte-derived small peritoneal macrophages (SPMs) and embryonically-seeded large peritoneal macrophages (LPMs). To determine the roles of SPMs and LPMs during intracellular infections, we infected mice intraperitoneally with the intracellular parasite Toxoplasma gondii, a robust driver of IFN-γ-mediated type 1 immune responses. We observed that T. gondii triggers a distinctive response in LPMs and SPMs responding to parasitic infection. Through the use of neutralizing antibodies, recombinant IFN-γ, and mice conditionally lacking expression of the IFN-γ receptor in macrophages, we have shown that the direct effects of IFN-γ are both required and sufficient for selective reprogramming of peritoneal macrophage subsets in response to T. gondii infection. Molecular mechanisms underlying the macrophage subset-specific effects of IFN-γ were further dissected in vivo and in vitro through imaging and omics approaches. Our results revealed the peritoneal macrophage subset-specific responses to IFN-γ that are essential for host resistance to T. gondii. Supported by the URMC T32 Immunology Training Grant AI00728, NIH R01 GR501266, and the Burroughs Wellcome Fund.

Metabolic Bone Disease of Prematurity.

Metabolic Bone Disease of Prematurity.

Exploring the applications of hyaluronic acid-based nanoparticles for diagnosis and treatment of bacterial infections.

Hyaluronic acid (HA) has become a topic of significant interest in drug delivery research due to its excellent properties, including biosafety, biodegradability, and nonimmunogenicity. Moreover, due to its ease of modification, HA can be used to prepare several HA‐based nanosystems using various approaches. These approaches involve conjugating/grafting of hydrophobic moieties, polyelectrolytes complexation with cationic polymers, or surface modification of various nanoparticles using HA. These nanoparticles are able to selectively deliver antibacterial drugs or diagnostic molecules into the site of infections. In addition, HA can bind with overexpressed cluster of differentiation 44 (CD44) receptors in macrophages and also can be degraded by a family of enzymes called hyaluronidase (HAase) to release drugs or molecules. By binding with these receptors or being degraded at the infection site by HAase, HA‐based nanoparticles allow enhanced and targeted antibacterial delivery. Herein, we present a comprehensive and up‐to‐date review that highlights various techniques of preparation of HA‐based nanoparticles that have been reported in the literature. Furthermore, we also discuss and critically analyze numerous types of HA‐based nanoparticles that have been employed in antibacterial delivery to date. This article offers a critical overview of the potential of HA‐based nanoparticles to overcome the challenges of conventional antibiotics in the treatment of bacterial infections. Moreover, this review identifies further avenues of research for developing multifunctional and biomimetic HA‐based nanoparticles for the treatment, prevention, and/or detection of pathogenic bacteria.This article is categorized under:Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious DiseaseNanotechnology Approaches to Biology > Nanoscale Systems in BiologyTherapeutic Approaches and Drug Discovery > Emerging Technologies

Acacetin Prevents Bone Loss by Disrupting Osteoclast Formation and Promoting Type H Vessel Formation in Ovariectomy-Induced Osteoporosis.

Osteoporosis, characterized by the destruction of bone resorption and bone formation, is a serious disease that endangers human health. Osteoporosis prevention and treatment has become one of the important research contents in the field of medicine. Acacetin, a natural flavonoid compound, could promote osteoblast differentiation, and inhibit osteoclast formation in vitro. However, the mechanisms of acacetin on osteoclast differentiation and type H vessel formation, as well as the effect of preventing bone loss, remain unclear. Here, we firstly used primary bone marrow derived macrophages (BMMs), endothelial progenitor cells (EPCs), and ovariectomized (OVX) mice to explore the function of acacetin on bone remodeling and H type vessel formation. In this study, we found that acacetin inhibits osteoclast formation and bone resorption of BMMs induced by the macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL) in a concentration of 20 μM without exerting cytotoxic effects. It was accompanied by downregulation of osteoclast differentiation marker genes (Ctsk, Acp5, and Mmp9) and cell fusion genes (CD9, CD47, Atp6v0d2, Dc-stamp, and Oc-stamp). Moreover, acacetin disrupted actin ring formation and extracellular acidification in osteoclasts. Mechanistic analysis revealed that acacetin not only inhibits the expression of the major transcription factor NFATc1 and NF-κB during RANKL-induced osteoclast formation, but also suppresses RANKL-induced the phosphorylation of Akt, GSK3β, IκBα, and p65. Additionally, acacetin enhanced the ability of M-CSF and RANKL-stimulated BMMs to promote angiogenesis and migration of EPCs. We further established that, in vivo, acacetin increased trabecular bone mass, decreased the number of osteoclasts, and showed more type H vessels in OVX mice. These data demonstrate that acacetin prevents OVX-induced bone loss in mice through inhibition of osteoclast function and promotion of type H vessel formation via Akt/GSK3β and NF-κB signalling pathway, suggesting that acacetin may be a novel therapeutic agent for the treatment of osteoporosis.

Monoclonal antibody Daratumumab promotes macrophage-mediated anti-myeloma phagocytic activity via engaging FC gamma receptor and activation of macrophages.

Daratumumab (DAR) is novel human anti-CD38 IgG1, high-affinity human monoclonal antibody having broad-spectrum killing activity. The antibody is recommended to treat multiple myeloma. Recently Antibody-dependent cellular phagocytosis (ADCP) have been identified as the potential mechanism of DAR in addition to complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC). In the present study we evaluated the effect of Daratumumab on other effector cells of multiple myeloma. Luciferase+ MM.1R GFP cells were selected for the study. For immune-compromised multiple myeloma tumour xenograft mouse model we used severe combined immunodeficient beige (SCID-beige), NOD SCID gamma (NSG) and C57Bl/6j mice. Bioluminescence imaging was carried by injecting luciferin, and in vivo confocal microscopy was done for tracing bone marrow niches. Spleen and tumours were submitted to immunophenotypic analysis. MTT assay was done for cell proliferation studies. We established tumour xenograft mouse model. It was found that DAR showed significant anti-tumour effect in tumour xenograft multiple myeloma mice. We found that DAR showed anti-tumour activity via Fc-FcγR interaction with macrophages. DAR induced phenotypic activation of macrophages in mice and resulted in ADCP of cancerous cells via interacting Fc-FcγR in vitro. The study suggested that DAR exerted anti-tumour activity in multiple myeloma by interacting with Fc-FcγR.

Association of the MARCO polymorphism rs6761637 with hepatocellular carcinoma susceptibility and clinical characteristics.

Hepatocellular carcinoma (HCC) remains a significant health problem with a substantial genetic predisposition. The liver harbors the largest proportion of macrophages among all the solid organs. There is considerable controversy regarding the relationship between the macrophage receptor with collagenous structure (MARCO) and tumor development and progression. Accordingly, we performed this case-control study to determine whether associations exist between the MARCO single nucleotide polymorphism rs6761637 and HCC susceptibility and clinical characteristics. We successfully genotyped 586 HCC cases and 647 controls using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The overall genotype distribution of rs6761637 was similar in the HCC and control groups (P = 0.143). However, the CT + CC genotypes of rs6761637 were slightly more common in the HCC group among female (P = 0.021), overweight (body mass index ≥ 24kg/m2, P = 0.003), and nonsmoking (P = 0.022) individuals. The minor C allele carriers had a 1.47-fold increased risk of developing large tumor nodules (P = 0.041). rs6761637 did not affect the recurrence-free or overall survival rate of patients with HCC (P = 0.247 and 0.304, respectively). In conclusion,this is the first report of the association between MARCO genetic variations and HCC risk. These results suggest that the MARCO rs6761637 polymorphism may play a regulatory role in HCC carcinogenesis, but it does not seem to predict prognosis.

Tie2 Receptor in Tumor-Infiltrating Macrophages Is Dispensable for Tumor Angiogenesis and Tumor Relapse after Chemotherapy.

Multiple preclinical tumor models, cell stimulation experiments, and meta-analysis of published tumor single cell RNA sequencing data challenge the reported role of Tie2-positive macrophages for tumor angiogenesis, metastasis, and relapse after chemotherapy. See related commentary by Zhang and Brekken, p. 1172.

Cathepsin D interacts with adenosine A2A receptors in mouse macrophages to modulate cell surface localization and inflammatory signaling

Adenosine A2A receptor (A2AR)–dependent signaling in macrophages plays a key role in the regulation of inflammation. However, the processes regulating A2AR targeting to the cell surface and degradation in macrophages are incompletely understood. For example, the C-terminal domain of the A2AR and proteins interacting with it are known to regulate receptor recycling, although it is unclear what role potential A2AR-interacting partners have in macrophages. Here, we aimed to identify A2AR-interacting partners in macrophages that may effect receptor trafficking and activity. To this end, we performed a yeast two-hybrid screen using the C-terminal tail of A2AR as the “bait” and a macrophage expression library as the “prey.” We found that the lysosomal protease cathepsin D (CtsD) was a robust hit. The A2AR–CtsD interaction was validated in vitro and in cellular models, including RAW 264.7 and mouse peritoneal macrophage (IPMΦ) cells. We also demonstrated that the A2AR is a substrate of CtsD and that the blockade of CtsD activity increases the density and cell surface targeting of A2AR in macrophages. Conversely, we demonstrate that A2AR activation prompts the maturation and enzymatic activity of CtsD in macrophages. In summary, we conclude that CtsD is a novel A2AR-interacting partner and thus describe molecular and functional interplay that may be crucial for adenosine-mediated macrophage regulation in inflammatory processes.

Enhancing effect of sodium butyrate on phosphatidylserine-liposome-induced macrophage polarization.

Phosphatidylserine-containing liposomes (PSLs) can mimic the immunomodulatory effects of apoptotic cells by binding to the phosphatidylserine receptors of macrophages. Sodium butyrate, an antiinflammatory short-chain fatty acid, is known to facilitate the M2 polarization of macrophages. This study aimed to investigate the effect of sodium butyrate on PSLs-induced macrophage polarization. PSLs physical properties and cellular uptake tests, reverse transcription-quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, immunofluorescence staining, and flow cytometry analysis were performed to assess the polarization-related indicators of M1/M2 macrophages. The results showed that sodium butyrate did not affect the size and cellular uptake of PSLs. For M1 macrophage polarization, sodium butyrate significantly intensified the antiinflammatory function of PSLs, inhibiting LPS-induced proinflammatory genes expression, cytokines and enzyme release (tumor necrosis factor-alpha, interleukin (IL)-1β, IL-6, and inducible nitric oxide synthase), as well as CD86 (M1 marker) expression. In addition to the enhancing effect of antiinflammation, sodium butyrate also promoted PSL-induced M2 macrophages polarization, especially elevated thymus and activation-regulated chemokine (TARC) and arginase-1 (Arg-1) enzyme levels which are involved in tissue repair. Sodium butyrate enhanced antiinflammatory properties and M2-polarization inducing effect of PSLs. Therefore, sodium butyrate may represent a novel approach to enhance PSL-induced macrophage polarization.

Correlation expression Toll-like receptor 4 with multidrugs resistant tuberculosis in diabetes mellitus condition

BackgroundToll-like receptor (TLR) are ligand homologous protein in the APC cell membrane that has functions as a receptor to triger leukocytes and innate immune responses. When there is a Microbacterium tuberculosis (MTB) infection enters from droplets to the lungs, the alveolar macrophages perform a phagocytic function. The interaction between M. tuberculosis and the TLR macrophage receptors produces chemokines which induce migration of monocytes and dendrite cells for destruction. Diabetes militus (DM) has become risk factor for developing tuberculosis. DM condition will reduce immunity and the ability of immune cell phagocytes bactery and triger severe infections. The consequences of more severe infection and metabolic disorders that occur make a person more likely to experience Multidrugs resistant MTB. Not much data that reports on the expression of TLR4 as a ligand that triggers an immune response in conditions of MDR and DM. We try to find out correlation between TLR-4 in MDR MTB, diabetes and level of MTB bacteria in experimental animals. MethodsWe conducted an experimental study on 30 experimental mice weighing 25 grams consisting of negative control grub, infected with MTB, infected with MDR MTB, negative control diabetes, MTB DM, MDR MTB DM. DM animals were induced by streptozosin to experience DM, then in the treatment of infection, intraperitoneal MTB and MDR MTB bacterial injections were given. Termination was carried out on day 14. We count number of bacteria level in the lungs and perform evaluation TLR4 from blood sampel. ResultsThe negative control group had mean TLR value of 1.47 (± 0.46) while the MTB group showed an increase in TLR 9.22 (± 0.39) followed by MDR MTB 9.50 (± 0.29), DM negative control 9, 21 (± 0.24) and more increasing in conditions of DM MTB 13.36 (± 0.32) and DM MDR MTB 13.35 (± 0.34). ANOVA analysis showed a significant difference (P = 0.00). pearson correlation analysis find strong correlation TLR4 in MTB and MDR MTB with diabetes. Conclusionthere were a significant difference level TLR4 between MTB and MDR TB infection with diabetes. higher TLR4 level higher in DM MTB, DM MDR MTB. TLR 4 strong correlates with an increase in the number of MTB bacteria.

Pathophysiological Advantages of Spontaneous Ventilation.

Surgical procedures cause stress, which can induce an inflammatory response and reduce immune function. Following video-assisted thoracoscopic surgery (VATS), non-intubated thoracic surgery (NITS) was developed to further reduce surgical stress in thoracic surgical procedures. This article reviews the pathophysiology of the NITS procedure and its potential for reducing the negative effects of mechanical one-lung ventilation (mOLV). In NITS with spontaneous ventilation, the negative side effects of mOLV are prevented or reduced, including volutrauma, biotrauma, systemic inflammatory immune responses, and compensatory anti-inflammatory immune responses. The pro-inflammatory and anti-inflammatory cytokines released from accumulated macrophages and neutrophils result in injury to the alveoli during mOLV. The inflammatory response is lower in NITS than in relaxed-surgery cases, causing a less-negative effect on immune function. The increase in leukocyte number and decrease in lymphocyte number are more moderate in NITS than in relaxed-surgery cases. The ventilation/perfusion match is better in spontaneous one-lung ventilation than in mOLV, resulting in better oxygenation and cardiac output. The direct effect of relaxant drugs on the acetylcholine receptors of macrophages can cause cytokine release, which is lower in NITS. The locoregional anesthesia in NITS is associated with a reduced cytokine release, contributing to a more physiological postoperative immune function.

Odorant receptors in macrophages: potential targets for atherosclerosis

In a recent report, Orecchioni et al. identify a role for the olfactory receptor (OR) Olfr2 and its human ortholog OR6A2 in atherosclerosis. Vascular macrophage Olfr2 binds octanal, a product of lipid peroxidation, activating the NLRP3 inflammasome and IL-1β secretion, and driving atherosclerosis pathology. Thus, OR6A2 inhibitors may represent a promising therapy for atherosclerosis.

MSR1 and NEP Are Correlated with Alzheimer's Disease Amyloid Pathology and Apolipoprotein Alterations.

In mouse models of amyloidosis, macrophage receptor 1 (MSR1) and neprilysin (NEP) have been shown to interact to reduce amyloid burden in the brain. The purpose of this study is to analyze these two gene products in combination with apolipoproteins and Aβ1-42 in the cerebrospinal fluid (CSF) and plasma of individuals at different stages of Alzheimer's disease (AD), as well as in autopsied brain samples from ROSMAP (Religious Orders Study and Memory and Aging Project). CSF/plasma levels of MSR1 and NEP were measured using the sensitive primer extension assay technology. CSF Aβ1-42 was assessed with ELISA, while CSF ApoE and ApoJ were measured with the Luminex's multiplex technology. Brain MSR1, APOE, and CLU (APOJ) mRNA levels were measured with RNA-Seq and contrasted to amyloid plaques pathology using CERAD staging. While plasma and CSF MSR1 levels are significantly correlated, this correlation was not observed for NEP. In addition to be highly correlated to one another, CSF levels of both MSR1 and NEP are strongly correlated with AD status and CSF Aβ1-42, ApoE, and ApoJ levels. In the cortical tissues of subjects from ROSMAP, MSR1 mRNA levels are correlated with CLU mRNA levels and the CERAD scores but not with APOE mRNA levels. The discrepancies observed between CSF/plasma levels of MSR1 and NEP with CSF Aβ1-42 and ApoE concentrations can be explained by many factors, such as the disease stage or the involvement of the blood-brain barrier breakdown that leads to the infiltration of peripheral monocytes or macrophages.

PLG nanoparticles target fibroblasts and MARCO+ monocytes to reverse multiorgan fibrosis.

Systemic sclerosis (SSc) is a chronic, multisystem orphan disease with a highly variable clinical course, high mortality rate, and a poorly understood complex pathogenesis. We have identified an important role for a subpopulation of monocytes and macrophages characterized by surface expression of the scavenger receptor macrophage receptor with collagenous structure (MARCO) in chronic inflammation and fibrosis in SSc and in preclinical disease models. We show that MARCO+ monocytes and macrophages accumulate in lesional skin and lung in topographic proximity to activated myofibroblasts in patients with SSc and in the bleomycin-induced mouse model of SSc. Short-term treatment of mice with a potentially novel nanoparticle, poly(lactic-co-glycolic) acid (PLG), which is composed of a carboxylated, FDA-approved, biodegradable polymer and modulates activation and trafficking of MARCO+ inflammatory monocytes, markedly attenuated bleomycin-induced skin and lung inflammation and fibrosis. Mechanistically, in isolated cells in culture, PLG nanoparticles inhibited TGF-dependent fibrotic responses in vitro. Thus, MARCO+ monocytes are potent effector cells of skin and lung fibrosis and can be therapeutically targeted in SSc using PLG nanoparticles.

Impact of former smoking exposure on airway eosinophilic activation and autoimmunity in patients with severe asthma.

Severe eosinophilic asthma is characterised by frequent exacerbations and a relative insensitivity to steroids. Experimentally, smoking may induce eosinophilic airway inflammation, but the impact in patients with severe asthma is not clear. To investigate the association between smoking exposure in patients with severe asthma, and eosinophilic inflammation and activation, as well as airway autoimmunity and steroid responsiveness. Patients with severe asthma according to European Respiratory Society/American Thoracic Society criteria were assessed with sputum samples, analysed by cell differential count, and for the presence of free eosinophil granules (FEGs), autoantibodies against eosinophil peroxidase (EPX) and macrophage receptor with collagenous structure (MARCO). A subgroup of patients with eosinophilic airway inflammation was re-assessed after a 2-week course of prednisolone. 132 severe asthmatics were included in the study. 39 (29.5%) patients had ≥10 pack-years of smoking history: 36 (27.3%) were former smokers and three (2.3%) current smokers; and 93 (70.5%) had <10 pack-years exposure. Eosinophilic airway inflammation was more prevalent among patients with ≥10 pack-years (66.7%), compared to patients with <10 pack-years (38.7%, p=0.03), as was the level of FEGs (p=0.001) and both anti-EPX and anti-MARCO (p<0.05 and p<0.0001, respectively). Omitting current smokers did not affect these associations. Furthermore, prednisolone reduced, but did not normalise, sputum eosinophils in patients with a ≥10 pack-year smoking history. In patients with severe asthma, a former smoking history is associated with eosinophilic airway inflammation and activation and relative insensitivity to steroids, as well as airway autoimmunity.

Nicotinic agonists promoted the activation of nicotinic acetylcholine α7 receptors (α7 nAChR) in neurons, but failed to activate these receptors in mouse peritoneal macrophages

Nicotinic acetylcholine receptor (nAChR) of subtypes said "neuronal" are expressed in epithelial and immune system cells and participate in acetylcholine signaling by neural or non-neural pathways. It has been shown in macrophages that activation of type a7 nAChRs inhibits the release of pro-inflammatory cytokines, but the ion channel function has not been recorded in these cells. The objective of this work was to clarify what are the molecular mechanisms of transduction of a7 nAChRs in macrophages. To this end, RAW 264.7 cells, mouse peritoneal macrophages and rat hippocampal neurons were used. Cells were submitted to electrophysiological studies and stimulated with brief applications of the agonists acetylcholine, choline and nicotine, associated or not with the allosteric modulator PNU-120596. Responses to ATP were recorded as a reference. Furthermore, macrophages were submitted to cytokine quantitation. The electrophysiological results showed that macrophages responded to ATP but did not show whole-cell current by stimulation with nicotinic agonists. However, hippocampal neurons stimulated in the same pharmacological conditions of the macrophages showed ionic currents typical of the a7 nicotinic receptors. No effect of nicotine was observed in the lipopolysaccharide-induced TNF-a release. These results suggest that the a7 nAChR in macrophages do not work as ion channels similar to those expressed in neurons.

Immunomodulatory activity of egg yolk protein hydrolysates prepared by novel two-step hydrolysis: A study of mechanism and stability after in vitro digestion model

The aim of this study was to determine the immunomodulatory activity of 2-step egg yolk protein hydrolysates. A two-step hydrolysate of egg yolk protein was prepared using 2 enzymes sequentially, pancreatin and neutrase (EYPH-PN). Our results illustrated that EYPH-PN increased the expression of inducible nitric oxide synthase (iNOS) mRNA in macrophages, resulting in increased nitric oxide (NO) production. EYPH-PN could also enhance the production of tumor necrosis factor (TNF)-α and interleukin (IL)-6 at both the mRNA and protein levels in macrophages. In addition, treatment with EYPH-PN increased the phagocytic activity of macrophages. According to the evaluation with specific inhibitors, both p38 and JNK cell signaling pathways were involved in the activation of macrophages induced by EYPH-PN. As the TLR-2 receptor of macrophages was blocked, the NO production induced by EYPH-PN was decreased. These results suggest that EYPH-PN activates RAW 264.7 macrophages via the TLR-2/p38/JNK pathway to increase the production of NO, TNF-α, and IL-6, and increases phagocytic activity. Furthermore, the immunomodulatory activity of EYPH-PN was maintained even after applying the in vitro digestion model. Taken together, EYPH-PN could be used as a functional food ingredient with excellent immunomodulatory activity in the food industry. Therefore, this study suggests a new alternative method to effectively utilize egg yolk protein, a by-product of the poultry industry.

Characterization of scavenger receptor MARCO in orange-spotted grouper, Epinephelus coioides

Macrophage receptor with collagenous structure (MARCO) is a scavenger receptor that plays a crucial role in the immune response against microbial infections. To clarify the roles of fish MARCO in Singapore grouper iridovirus (SGIV) infection, we identified and characterized Ec-MARCO in the orange-spotted grouper (Epinephelus coioides). The Ec-MARCO encoded a 370-amino acid protein with transmembrane region, coiled coil region and SR domain, which shared high identities with reported MARCO. The abundant transcriptional level of Ec-MARCO was found in spleen, head kidney and blood. And the Ec-MARCO expression was significantly up-regulated in grouper spleen (GS) cells after infection with SGIV in vitro. Subcellular localization analysis revealed that Ec-MARCO was mainly distributed in the cytoplasm and on the cell membrane. Ec-MARCO knockdown in vitro significantly inhibited SGIV infection in GS cells, as evidenced by reduced decreased SGIV major capsid protein (MCP) transcription and MCP protein expression. Further studies showed that Ec-MARCO knockdown positively regulated proinflammatory cytokines and interferon-stimulated genes, and enhanced IFN and ISRE promoter activities. However, overexpression of Ec-MARCO did not affect SGIV entry into host cells. In summary, our results suggested that Ec-MARCO affected SGIV infection by regulating antiviral innate immune response.

MicroRNA-200c Attenuates the Tumor-Infiltrating Capacity of Macrophages.

Simple SummaryThe tumor microenvironment determines the prognosis and outcome for cancer patients. Herein, tumor-associated macrophages are not only highly abundant, but also play a crucial role in shaping a tumor-supporting microenvironment. Both their recruitment to the tumor as well as their functional polarization toward a pro-tumorigenic phenotype are mediated by tumor-derived factors including microRNAs. However, the impact of most microRNAs on the tumor cell-macrophage crosstalk remains to be elucidated. Thus, we reached out to investigate the role of hsa-miR-200c-3p (miR-200c) in tumor cell–macrophage interactions, as it was shown to be differentially expressed during cancer progression and metastasis. miR-200c was highly expressed in MCF7 breast tumor cells compared to macrophages. Furthermore, we identified a CD36-dependent uptake of miR-200c, derived from apoptotic tumor cells, into macrophages. In macrophages, elevated miR-200c levels reduced the expression of numerous migration-associated mRNAs, consequently reducing the capacity of macrophages to infiltrate into tumor spheroids. Finally, a distinct signature of miR-200c-repressed, predicted targets was identified, which strongly correlated with tumor infiltration. Targeting the miR-200c transfer from dying tumor cells to macrophages might therefore provide the opportunity to specifically modulate tumor-associated macrophage recruitment.Macrophages constitute a major part of the tumor-infiltrating immune cells. Within the tumor microenvironment, they acquire an alternatively activated, tumor-supporting phenotype. Factors released by tumor cells are crucial for the recruitment of tumor-associated macrophages. In the present project, we aimed to understand the role of hsa-miR-200c-3p (miR-200c) in the interplay between tumor cells and macrophages. To this end, we employed a coculture system of MCF7 breast tumor cells and primary human macrophages and observed the transfer of miR-200c from apoptotic tumor cells to macrophages, which required intact CD36 receptor in macrophages. We further comprehensively determined miR-200c targets in macrophages by mRNA-sequencing and identified numerous migration-associated mRNAs to be downregulated by miR-200c. Consequently, miR-200c attenuated macrophage infiltration into 3-dimensional tumor spheroids. miR-200c-mediated reduction in infiltration further correlated with a miR-200c migration signature comprised of the four miR-200c-repressed, predicted targets PPM1F, RAB11FIB2, RDX, and MSN.