Human Peripheral Blood Monocytes Research Articles

Exosomal miR-27a-3p derived from tumor-associated macrophage suppresses propranolol sensitivity in infantile hemangioma

Propranolol is the first-line drug for infantile hemangioma (IH) therapy, whereas propranolol resistance is clinically observed. Tumor-associated macrophages (TAMs)-derived exosomes may deliver biological molecules to promote tumor progression. Here, we aimed to investigate the relationship between TAMs-derived exosomal miR-27a-3p and propranolol sensitivity in IH. Human peripheral blood monocytes (PBMCs) were cultured with macrophage colony-stimulating factor (M-CSF) for 7 days to get unactivated macrophages (Un-Mac), which were further treated with IL-4 and IL-13 to induce M2 polarized macrophages. Exosomes were isolated from the conditioned medium of M2 macrophage, followed by identification. Cell co-culture and/or transfection were performed to explore whether M2 polarized macrophage-derived exosomes (M2-exos) could mediate the crosstalk between TAMs-derived miR-27a-3p and hemangioma stem cells (HemSCs). In addition, nude mice were subcutaneously transplanted with HemSCs pretreated with or without M2-Exos to examine the effects of M2-Exos on IH in vivo. M2 polarized macrophages inhibited propranolol sensitivity of HemSCs, as shown by the increased cell viability and decreased apoptosis. miR-27a-3p was upregulated in M2 polarized macrophages and M2-Exos. Moreover, M2-exos delivered miR-27a-3p from macrophages to HemSCs and subsequently reduced propranolol sensitivity. Luciferase reporter and biotin-RNA pulldown assay proved that dickkopf-related protein 2 (DKK2) was the direct target of miR-27a-3p. These results demonstrate that M2-exos could deliver miR-27a-3p from macrophages to HemSCs to reduce the sensitivity of HemSCs to propranolol by down-regulating DKK2 expression, and exosomal miR-27a-3p and DKK2 in HemSCs could be considered as treatment targets.

Generation and functional characterization of recombinant Porphyromonas gingivalis W83 FimA

Porphyromonas gingivalis (P. gingivalis) is regarded as a keystone pathogen in destructive periodontal diseases. It expresses a variety of virulence factors, amongst them fimbriae that are involved in colonization, invasion, establishment and persistence of the bacteria inside the host cells. The fimbriae also were demonstrated to affect the host immune-response mechanisms. The major fimbriae are able to bind specifically to different host cells, amongst them peripheral blood monocytes. The interaction of these cells with fimbriae induces release of cytokines such as interleukin-1 (IL-1), IL-6, and tumor necrosis factor-α (TNF-α). The aim of this study was to generate recombinant major FimA protein from P. gingivalis W83 fimbriae and to prove its biological activity. FimA of P. gingivalis W83 was amplified from chromosomal DNA, cloned in a vector and transferred into Listeria innocua. (L. innocua).The expressed protein was harvested and purified using FPLC via a His trap HP column. The identity and purity was demonstrated by gel-electrophoresis and mass-spectrometry. The biological activity was assessed by stimulation of human oral epithelial cells and peripheral blood monocytes with the protein and afterwards cytokines in the supernatants were quantified by enzyme linked immunosorbent assay (ELISA) and cytometric bead array. Recombinant FimA could successfully be generated and purified. Gel-electrophoresis and mass-spectrometry confirmed that the detected sequences are identical with FimA. Stimulation of human monocytes induced the release of high concentrations of IL-1β, IL-6, IL-10 and TNF-α by these cells. In conclusion, a recombinant FimA protein was established and its biological activity was proven. This protein may serve as a promising agent for further investigation of its role in periodontitis and possible new therapeutic approaches.

Human Lung-Resident Macrophages Express and Are Targets of Thymic Stromal Lymphopoietin in the Tumor Microenvironment.

Thymic stromal lymphopoietin (TSLP) is a pleiotropic cytokine highly expressed by epithelial cells and several innate and adaptive immune cells. TSLP exerts its biological effects by binding to a heterodimeric complex composed of TSLP receptor (TSLPR) and IL-7Rα. In humans, there are two TSLP isoforms: the short form (sfTSLP), constitutively expressed, and the long form (lfTSLP), which is upregulated in inflammation. TSLP has been implicated in the induction and progression of several experimental and human cancers. Primary human lung macrophages (HLMs), monocyte-derived macrophages (MDMs), and peripheral blood monocytes consitutively expressed sfTSLP mRNA. Incubation of HLMs, MDMs, and monocytes with lipopolysaccharide (LPS) or IL-4, but not with IL-13, induced TSLP release from HLMs. LPS, but not IL-4 or IL-13, induced CXCL8 release from HLMs. LPS, IL-4 alone or in combination with IL-13, induced the expression of lfTSLP, but not of sfTSLP from HLMs. Preincubation of HLMs with IL-4, alone or in combination with IL-13, but not IL-13 alone, synergistically enhanced TSLP release from LPS-activated macrophages. By contrast, IL-4, alone or in combination with IL-13, inhibited LPS-induced CXCL8 release from HLMs. Immunoreactive TSLP was detected in lysates of HLMs, MDMs, and monocytes. Incubation of HLMs with TSLP induced the release of proinflammatory (TNF-α), angiogenic (VEGF-A, angiopoietin 2), and lymphangiogenic (VEGF-C) factors. TSLP, TSLPR, and IL-7Rα were expressed in intratumoral and peritumoral areas of human lung cancer. sfTSLP and lfTSLP mRNAs were differentially expressed in peritumoral and intratumoral lung cancer tissues. The TSLP system, expressed in HLMs, MDMs, and monocytes, could play a role in chronic inflammatory disorders including lung cancer.

CX3CL1/fractalkine regulates the differentiation of human peripheral blood monocytes and monocyte-derived dendritic cells into osteoclasts

Osteoclast differentiation is promoted under inflammatory conditions and osteoclasts play a major role in bone destruction in rheumatoid arthritis (RA). Chemokine (C-X3-C motif) ligand 1 (CX3CL1), also known as fractalkine, functions as a chemoattractant and adhesion molecule, and is involved in the pathogenesis of RA. The blockade of CX3CL1 inhibits the migration of macrophages and osteoclast precursor cells into the inflamed synovium. In the present study, we investigated the direct stimulatory effects of CX3CL1 on osteoclast differentiation from human peripheral blood monocytes and monocyte-derived dendritic cells. A stimulation with CX3CL1 significantly promoted osteoclast differentiation from CD16- monocytes and also monocyte-derived dendritic cells induced by macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-κB ligand (RANKL). On the other hand, CD16+ monocytes treated with M-CSF and RANKL did not differentiate into osteoclasts, even with CX3CL1. Calcium resorption was significantly increased by monocyte-derived osteoclasts, but not by dendritic cell-derived osteoclasts, following the addition of CX3CL1. The present results suggest that CX3CL1 directly regulates osteoclast differentiation. CX3CL1 may play important roles in the pathogenesis of RA, not only through the accumulation of inflammatory cells, but also through osteoclastogenesis.

Effects of 17β-Estradiol on Monocyte/Macrophage Response to Staphylococcus aureus: An In Vitro Study.

To describe how 17β-estradiol (E2) influence in the monocyte/macrophage response induced by S. aureus in in vitro models of murine peritoneal macrophages (MPMs) and human peripheral blood monocytes (HPBM). MPMs (2 x 105/ml) were isolated from sham (n=3) and ovariectomized (OVX) females (n = 3) and males (n = 3) after induction by thioglycolate. The MPMs obtained from OVX females and males were treated for 24 hours with 17β-estradiol (E2) (10-7 M), and after that, inoculation with S. aureus was carried out for 6 hours. The macrophages were collected and destined to evaluate the relative gene expression of TNF-α, IL-1β, IL-6, IL-8 and TLR2. For the in vitro model of HPBMs, six men and six women of childbearing age were selected and HPBMs were isolated from samples of the volunteers’ peripheral blood. In women, blood was collected both during menstruation and in the periovulatory period. HPBMs were inoculated with S. aureus for 6 hours and the supernatant was collected for analysis of cytokines by Luminex and the HPBMs were removed for analysis of 84 genes involved in the host’s response to bacterial infections by RT-PCR array. Previous treatment with E2 decreased the gene expression and production of proinflammatory cytokines, such as TNF-α, IL-1β and IL-6 and decreased the expression of TLR2 tanto em MPMs quanto em HPBMs. The analysis of gene expression shows that E2 inhibited the NFκB pathway. It is suggested that 17β-estradiol acts as an immunoprotective in the monocyte/macrophage response induced by S. aureus.

PCB cause global DNA hypomethylation of human peripheral blood monocytes in vitro

We have recently reported significant associations between exposure to polychlorinated biphenyls (PCB) and alterations on genome-wide methylation of leukocyte DNA of healthy volunteers and provided evidence in support of an etiological link between the observed CpG methylation variations and chronic lymphocytic leukemia. The present study aimed to elucidate the effects of PCB in human lymphocytes’ methylome in vitro. Therefore, U937 cells and human peripheral blood monocytes (PBMC) were exposed in vitro to the dioxin-like PCB-118, the non-dioxin-like PCB-153, and hexachlorobenzene (HCB) and thorough cytotoxicity, genotoxicity and global CpG methylation analyses were performed. All compounds currently tested did not show any consistent significant genotoxicity at all exposure periods and concentrations used. On the contrary, extensive dose-dependent hypomethylation was observed, even at low concentrations, in stimulated PBMC treated with PCB-118 and PCB-153 as well as a small but statistically significant hypomethylation in HCB-treated stimulated cells.

The Oxidative Response of Human Monocytes to Surface Modified Commercially Pure Titanium.

Cellular responses to implanted biomaterials are key to understanding osseointegration. The aim of this investigation was to determine the in vitro priming and activation of the respiratory burst activity of monocytes in response to surface-modified titanium. Human peripheral blood monocytes of healthy blood donors were separated, then incubated with surface-modified grade 2 commercially pure titanium (CPT) disks with a range of known surface energies and surface roughness for 30- or 60-min. Secondary stimulation by phorbol 12-myrisate 13-acetate (PMA) following the priming phase, and luminol-enhanced-chemiluminescence (LCL) was used to monitor oxygen-dependent activity. Comparison among groups was made by incubation time using one-way ANOVA. One sample from each group for each phase of the experiment was viewed under scanning electron microscopy (SEM) and qualitative comparisons made. The results indicate that titanium is capable of priming peripheral blood monocytes following 60-min incubation. In contrast, 30 min incubation time lead to reduced LCL on secondary stimulation as compared to cells alone. At both time intervals, the disk with the lowest surface energy produced significantly less LCL compared to other samples. SEM examination revealed differences in surface morphology at different time points but not between differently surface-modified disks. These results are consistent with the hypothesis that the titanium surface characteristics influenced the monocyte activity, which may be important in regulating the healing response to these materials.

Profile of host cell responses to exposure to stressed bacteria in planktonic; dislodged, and intact biofilm mode.

The host defense response to microbial challenge emerging from the root canal system leads to apical periodontitis. The aim of this study was to evaluate the expression of inflammatory cytokines and Nitric Oxide (NO) by macrophages after interaction with Enterococcus faecalis in the: plankton and dislodged biofilm mode; intact biofilm mode stimulated by calcium hydroxide (CH), CH and chlorhexidine (CHX) or Triple Antibiotic Paste (TAP). For this purpose, culture of macrophages from monocytes in human peripheral blood (N=8) were exposed to the different modes of bacteria for 24 hours. Subsequently, the cytokines, such as, Tumor Necrotic Factor- alfa (TNF-α), interleukin (IL)-1β, IL-6, IL-10; and NO were quantified by Luminex xMAP and Greiss reaction, respectively. In addition to the potential therapeutic effects of the intracanal medication, their antimicrobial activity against Enterococcus faecalis biofilm were also tested in vitro by confocal microscopy. The experiments` data were analyzed by the Kruskal-Wallis test with the Dunn post hoc test (α < 0.05). Bacteria in dislodged biofilm mode were shown to be more aggressive to the immune system than bacteria in plankton mode and negative control, inducing greater expression of NO and TNF-α. Relative to bacteria in intact biofilm mode, the weakest antimicrobial activity occurred in Group CH. In Groups CH/CHX and TAP the percentage of dead bacteria was significantly increased to the same extent. Interestingly, the biofilm itself did not induce the release of pro-inflammatory cytokines - except for NO - while the biofilm treated with TAP and CH based pastes enhanced the levels of IL-6 and TNF-α; and IL-1 β, respectively. In contrast, the levels of a potent anti-inflammatory (IL-10) were increased in Group TAP.

Phenotypic and genetic evaluation of human monocyte-derived dendritic cells generated from whole blood for immunotherapy

BackgroundDendritic cells (DCs) recognize different pathogens and cancer cells and activate the adaptive immune response. The generation of effective DC-based cancer vaccines depends on the appropriate differentiation of monocytes in vitro. This study aimed to standardize a protocol for the in vitro differentiation of human peripheral blood monocytes into immature DCs upon treatment with growth factors and generate monocyte-derived DCs (MoDCs). Peripheral blood mononuclear cells were separated from peripheral blood. After monocyte enrichment by plastic adhesion, monocytes were cultured for 6 days in the presence of granulocyte-macrophage colony-stimulating factor and interleukin-4 to generate immature DCs. The cells were examined by microscopy. Using flow cytometry, DCs were evaluated for the expression of the CD83 and HLA-DR surface antigens, for the uptake of fluorescein isothiocyanate conjugated dextran, and also for the expression of CD80 and CD86 mRNA.ResultsCD80 and CD86 genes expression was upregulated at day six and exhibited a significant difference (P < 0.05). DCs showed positive expression of the CD83 and HLA-DR surface antigens by flow cytometry and FITC-conjugated dextran uptake.ConclusionThis study represents a preliminary trial to generate immature MoDCs in vitro from blood monocytes collected by the flask adherence method. It offers a panel of surface markers for DCs characterization and provides Immature DCs for experimental procedures after 6 incubation days.

Repression of CTSG, ELANE and PRTN3-mediated histone H3 proteolytic cleavage promotes monocyte-to-macrophage differentiation.

Chromatin undergoes extensive reprogramming during immune cell differentiation. Here we report repression of controlled histone H3 amino-terminus proteolytic cleavage (H3ΔN) during monocyte-to-macrophage development. This abundant histone mark in human peripheral blood monocytes is catalyzed by neutrophil serine proteases (NSPs) cathepsin G, neutrophil elastase, and proteinase 3. NSPs are repressed as monocytes mature into macrophages. Integrative epigenomic analysis reveals widespread H3ΔN distribution across the genome in a monocytic cell line and primary monocytes, which becomes largely undetectable in fully differentiated macrophages. H3ΔN is enriched at permissive chromatin and actively transcribed genes. Simultaneous NSP depletion in monocytic cells results in H3ΔN loss and further increase in chromatin accessibility, which likely primes the chromatin for gene expression reprogramming. Importantly, H3ΔN is reduced in monocytes from patients with systemic juvenile idiopathic arthritis (sJIA), an autoinflammatory disease with prominent macrophage involvement. Together, we uncover an epigenetic mechanism that primes the chromatin to facilitate macrophage development.

Plastrum testudinis extract suppresses osteoclast differentiation via the NF-κB signaling pathway and ameliorates senile osteoporosis

Ethnopharmacological relevancePlastrum testudinis (PT) is a kind of single traditional Chinese medicine that can tonify kidney and strengthen bone. Plastrum testudinis extract (PTE) has been approved to promote the osteogenic differentiation of bone marrow-derived mesenchymal stem cells in vitro. However, the mechanism by which PTE reduces osteoclast differentiation has not yet been reported. Aim of the studyTo explore the potential of PTE as a therapeutic treatment for bone loss caused by senile osteoporosis (SOP). Materials and methodsWe evaluated whether PTE could inhibit RANKL-induced osteoclast differentiation both in vitro and in vivo, and investigated PTE-induced phenotypes of human peripheral blood monocytes. ResultsWe found that PTE inhibited osteoclast differentiation and bone resorption in vitro in a concentration-dependent manner and that PTE treatment is most effective during the early stages of osteoclastogenesis. Moreover, we found that PTE could block the NF-κB signaling pathway in vitro, leading to the down-regulation of osteoclast-specific genes including C-FOS and NFATC1. The results from our in vivo mouse study suggest that PTE treatment suppresses osteoclast formation and mitigates bone loss caused by SOP. Notably, we also found that PTE inhibited RANKL-induced osteoclast differentiation in human peripheral blood monocytes. ConclusionOur results suggest that PTE treatment suppresses osteoclastogenesis and ameliorates bone loss caused by SOP by selectively blocking the nuclear translocation of NF-κB/p50.

Effects of paclitaxel in mitochondrial function and cellular phenotype in human peripheral blood mononuclear cells and monocytes

Chemotherapy-induced neuropathy (CIPN) is a common complication of paclitaxel. CIPN affects the quality of life of cancer survivors and frequently leads to discontinuation of treatment. Paclitaxel affects neuronal microtubules and induces neuronal mitochondrial dysfunction. However, there is limited clinical information regarding paclitaxel's effects on monocytes. Preclinical studies suggest that paclitaxel-induced neuronal damage is driven by monocytes/macrophages. Therefore, we evaluated whether paclitaxel selectively induces mitochondrial dysfunction and a pro-inflammatory phenotype in human circulating monocytes. We conducted studies in human primary peripheral blood mononuclear cells (PBMCs) from cancer patients being treated with paclitaxel, and in vitro analysis in PBMC cells and monocytes, and THP-1 monocytes in the presence of paclitaxel (0.1, 1, 10 uM). We used flow cytometric markers to study mitochondrial reactive oxygen species (ROS) and mitochondrial membrane potential, namely MitoSox and DIOC6(3) respectively. We also measured mRNA levels of pro- and anti-inflammatory molecules using qRT-PCR. In vitro paclitaxel induced a depolarization state in mitochondria in THP-1, human primary monocytes, and primary human PBMCs, but it did not change MitoSox. Monocytes in PBMCs cells from patients treated with paclitaxel showed significative depolarization state in mitochondria when compared to cells from control patients. In THP-1 cells, paclitaxel enhanced mRNA levels of the pro-inflammatory cytokines IL-8 and TNF alpha. In human primary PBMCs, paclitaxel reduced the anti-inflammatory factors CD163 and IL-10, and enhanced the TNF alpha, COX-2 and MCP-1 mRNA levels. Our study provides evidence that paclitaxel can induce mitochondrial dysfunction in isolated human monocytes and in monocytes present in total PBMCs cells. The observed depolarizing changes are indicative of a pro-mitophagy state, which is in accordance with the paclitaxel-induced pro-inflammatory phenotype in these cells. Early detection of mitochondria dysfunction in human monocytes could be a predictable sign to CIPN development in cancer patients. Our research was supported by the Early-Career Investigator Award W81XWH-16-1-0438 of the Department of Defense, The Pershing Square Sohn Cancer Research Alliance, Weill Cornell Medicine Funds, Department of Anesthesiology-Wake Forest School of Medicine Funds, Comprehensive Cancer Center-Wake Forest School of Medicine Funds, NIDA R21CA248106, National Center for Advancing Translational Sciences (NCATS)-NIH through Grant Award Number UL1TR001420. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

Exploring the Biomaterial-Induced Secretome: Physical Bone Substitute Characteristics Influence the Cytokine Expression of Macrophages.

In addition to their chemical composition various physical properties of synthetic bone substitute materials have been shown to influence their regenerative potential and to influence the expression of cytokines produced by monocytes, the key cell-type responsible for tissue reaction to biomaterials in vivo. In the present study both the regenerative potential and the inflammatory response to five bone substitute materials all based on β-tricalcium phosphate (β-TCP), but which differed in their physical characteristics (i.e., granule size, granule shape and porosity) were analyzed for their effects on monocyte cytokine expression. To determine the effects of the physical characteristics of the different materials, the proliferation of primary human osteoblasts growing on the materials was analyzed. To determine the immunogenic effects of the different materials on human peripheral blood monocytes, cells cultured on the materials were evaluated for the expression of 14 pro- and anti-inflammatory cytokines, i.e., IL-6, IL-10, IL-1β, VEGF, RANTES, IL-12p40, I-CAM, IL-4, V-CAM, TNF-α, GM-CSF, MIP-1α, Il-8 and MCP-1 using a Bio-Plex® Multiplex System. The granular shape of bone substitutes showed a significant influence on the osteoblast proliferation. Moreover, smaller pore sizes, round granular shape and larger granule size increased the expression of GM-CSF, RANTES, IL-10 and IL-12 by monocytes, while polygonal shape and the larger pore sizes increased the expression of V-CAM. The physical characteristics of a bone biomaterial can influence the proliferation rate of osteoblasts and has an influence on the cytokine gene expression of monocytes in vitro. These results indicate that the physical structure of a biomaterial has a significant effect of how cells interact with the material. Thus, specific characteristics of a material may strongly affect the regenerative potential in vivo.

Corrigendum for Oda et al., volume 291, 2006, p. C104–C113

CorrigendumCorrigendum for Oda et al., volume 291, 2006, p. C104–C113Published Online:19 Apr 2021https://doi.org/10.1152/ajpcell.00614.2005_COROriginal articleMoreSectionsPDF (336 KB)Download PDFDownload PDFPlus ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmail Oda T, Hirota K, Nishi K, Takabuchi S, Oda S, Yamada H, Arai T, Fukuda K, Kita T, Adachi T, Semenza GL, Nohara R. Activation of hypoxia-inducible factor 1 during macrophage differentiation. Am J Physiol Cell Physiol 291: C104–C113, 2006. First published February 15, 2006; doi:10.1152/ajpcell.00614.2005.—In the above article, blots in Figs. 2 and 7 were published incorrectly. Below are the corrected figures and revised Fig. 7 legend. The authors assert that the corrections do not affect the conclusions of the figures or the study.Figure 2.Dose- and time-dependent effect of differentiation-inducing agents on HIF-1 protein expression under 20% O2 conditions. THP-1 cells were exposed to the indicated concentration of PMA for 72 h (A), 100 nM PMA for the indicated time (B), or 1 μM ATRA for the indicated time (C), and harvested for immunoblot assay using anti-HIF-1α (top), HIF-1β (middle), or β-actin (bottom) antibody. D: Jurkat T cells were exposed to 100 nM PMA for the indicated time and harvested for immunoblot assay using anti-HIF-1α (top), HIF-1β (middle), or β-actin (bottom) antibody.Download figureDownload PowerPointFigure 7.MAPK, AKT, the translational regulators p70S6K, S6 ribosomal protein, 4E-BP1, and eIF-4E phosphorylation are induced by PMA treatment. A, B, and D: whole cell lysates were prepared and subjected to immunoblot assays using antibodies specific for phosphorylated (Thr-202/Tyr-204), total p42ERK2/p44ERK1 MAPK, phosphorylated (Ser-473) or total AKT. THP-1 cells were exposed to 100 nM PMA for the indicated time under 20% O2 conditions. Three time points in the original figure were spliced out to prepare 7B to combine bands corresponding to time points 48 h and 72 h next to each other, which is indicated in the figure as well. C: human peripheral blood monocytes (mono) were allowed to differentiate to macrophages (macro). In D, whole cell lysates were prepared and subjected to immunoblot assays using antibodies specific for phosphorylated (Thr-389) p70S6K (PS6K), phosphorylated (Ser-235/Ser-236) S6 ribosomal protein (S6R), phosphorylated (Ser-65) 4E-BP1 (P4E-BP1), and phosphorylated (Ser-209) eIF-4E (PeIF-4E).Download figureDownload PowerPointThis article has no references to display. Previous Back to Top FiguresReferencesRelatedInformationRelated articlesActivation of hypoxia-inducible factor 1 during macrophage differentiation 01 Jul 2006American Journal of Physiology-Cell Physiology More from this issue > Volume 320Issue 4April 2021Pages C666-C667 Crossmark Copyright & PermissionsCopyright © 2021 the American Physiological Society.https://doi.org/10.1152/ajpcell.00614.2005_CORPubMed33871285History Published online 19 April 2021 Published in print 1 April 2021 PDF download Metrics Downloaded 256 times

Neoadjuvant Chemotherapy Induces IL34 Signaling and Promotes Chemoresistance via Tumor-Associated Macrophage Polarization in Esophageal Squamous Cell Carcinoma.

The tumor microenvironment (TME) plays a key role in the efficacy of neoadjuvant chemotherapy (NAC) in solid tumors including esophageal squamous cell carcinoma (ESCC). However, the TME profile of ESCC treated with NAC is not fully understood. In this study, we investigated the effect of NAC on the TME especially tumor-associated macrophages (TAM), the important immunosuppressive components of the TME, in ESCC. We quantified the expression of CD163, a crucial marker of TAM, in pretherapeutic biopsy and surgically resected ESCC specimens from patients who received NAC (n = 33) or did not receive NAC (n = 12). We found that NAC dramatically increased the expression of CD163 on TAMs in ESCC. Colony-stimulating factor 1 (CSF-1) and IL34 are crucial cytokines that recruit monocytes into tumor sites and differentiate them into TAMs. Interestingly, NAC significantly upregulated the expression of IL34 but not CSF-1 on tumor cells, and the frequencies of CD163+ TAMs were significantly correlated with IL34 expression in ESCC after NAC. The expression of IL34 in NAC-nonresponsive patients was significantly higher than that in NAC-responsive patients, and patients with IL34-high ESCC exhibited worse prognosis as compared with patients with IL34-low ESCC. We also demonstrated that 5-fluorouracil (5-FU)/cisplatin preferentially increased mRNA expression of IL34 on human ESCC cell lines. Human peripheral blood monocytes co-cultured with ESCC cells treated with 5-FU/cisplatin increased the expression of CD163, which was attenuated by the treatment with CSF-1R inhibitors. These data suggest that IL34 expression by NAC shifts the TME toward CD163+ TAM-rich immunosuppressive and chemo-insensitive microenvironment in ESCC. IMPLICATIONS: The blockade of IL34 signaling may offer a novel therapeutic strategy against chemoresistance in ESCC by inhibiting M2-TAM polarization.

Structural insight reveals SARS-CoV-2 ORF7a as an immunomodulating factor for human CD14+ monocytes

SummaryDysregulated immune cell responses have been linked to the severity of coronavirus disease 2019 (COVID-19), but the specific viral factors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were currently unknown. Herein, we reveal that the Immunoglobulin-like fold ectodomain of the viral protein SARS-CoV-2 ORF7a interacts with high efficiency to CD14+ monocytes in human peripheral blood, compared to pathogenic protein SARS-CoV ORF7a. The crystal structure of SARS-CoV-2 ORF7a at 2.2 Å resolution reveals three remarkable changes on the amphipathic side of the four-stranded β-sheet, implying a potential functional interface of the viral protein. Importantly, SARS-CoV-2 ORF7a coincubation with CD14+ monocytes ex vivo triggered a decrease in HLA-DR/DP/DQ expression levels and upregulated significant production of proinflammatory cytokines, including IL-6, IL-1β, IL-8, and TNF-α. Our work demonstrates that SARS-CoV-2 ORF7a is an immunomodulating factor for immune cell binding and triggers dramatic inflammatory responses, providing promising therapeutic drug targets for pandemic COVID-19.

The NKG2D ligand ULBP4 is not expressed by human monocytes.

The C-type lectin-like receptor NKG2D contributes to the immunosurveillance of virally infected and malignant cells by cytotoxic lymphocytes. A peculiar and puzzling feature of the NKG2D-based immunorecognition system is the high number of ligands for this single immunoreceptor. In humans, there are a total of eight NKG2D ligands (NKG2DL) comprising two members of the MIC (MICA, MICB) and six members of the ULBP family of glycoproteins (ULBP1 to ULBP6). While MICA has been extensively studied with regard to its biochemistry, cellular expression and function, very little is known about the NKG2DL ULBP4. This is, at least in part, due to its rather restricted expression by very few cell lines and tissues. Recently, constitutive ULBP4 expression by human monocytes was reported, questioning the view of tissue-restricted ULBP4 expression. Here, we scrutinized ULBP4 expression by human peripheral blood mononuclear cells and monocytes by analyzing ULBP4 transcripts and ULBP4 surface expression. In contrast to MICA, there was no ULBP4 expression detectable, neither by freshly isolated monocytes nor by PAMP-activated monocytes. However, a commercial antibody erroneously indicated surface ULBP4 on monocytes due to a non-ULBP4-specific binding activity, emphasizing the critical importance of validated reagents for life sciences. Collectively, our data show that ULBP4 is not expressed by monocytes, and likely also not by other peripheral blood immune cells, and therefore exhibits an expression pattern rather distinct from other human NKG2DL.

Role of miR-466 in mesenchymal stromal cell derived extracellular vesicles treating inoculation pneumonia caused by multidrug-resistant Pseudomonas aeruginosa.

RationaleThe effects of mesenchymal stromal cells (MSCs) and MSC‐derived extracellular vesicles (MSC EVs) on multidrug‐resistant pseudomonas aeruginosa (MDR‐PA)‐induced pneumonia remain unclear.Materials and methodsMicroRNA array and RT‐PCR were used to select the major microRNA in MSC EVs. Human peripheral blood monocytes were obtained and isolated from qualified patients. The crosstalk between MSCs/MSC EVs and macrophages in vitro was studied. MDR‐PA pneumonia models were further established in C57BL/6 mice and MSC EVs or miR‐466 overexpressing MSC EVs were intratracheally instilled.ResultsMiR‐466 was highly expressed in MSC EVs. MSCs and miR‐466 promoted macrophage polarization toward Type 2 phenotype through TIRAP‐MyD88‐NFκB axis. Moreover, cocultured macrophages with miR‐466 overexpressing MSCs significantly increased the phagocytosis of macrophages. MSC EVs significantly reduced mortality and decreased influx of BALF neutrophils, proinflammatory factor levels, protein, and bacterial load in murine MDR‐PA pneumonia. Administration of miR‐466 overexpressing MSC EVs further alleviated the inflammatory severity.ConclusionsMSC‐derived EVs containing high levels of miR‐466 may partly participate in host immune responses to MDR‐PA. Both MSCs and MSC EVs have therapeutic effects in treating MDR‐PA‐induced pneumonia.

A PKCβ-LYN-PYK2 Signaling Axis Is Critical for MCP-1-Dependent Migration and Adhesion of Monocytes.

MCP-1-induced monocyte chemotaxis is a crucial event in inflammation and atherogenesis. Identifying the important signal transduction pathways that control monocyte chemotaxis can unravel potential targets for preventive therapies in inflammatory disease conditions. Previous studies have shown that the focal adhesion kinase Pyk2 plays a critical role in monocyte motility. In this study, we investigated the MCP-1-mediated activation of Pyk2 (particularly by the phosphorylation of Tyr402) in primary human peripheral blood monocytes. We showed that MCP-1 induces Src phosphorylation in a similar time frame and that the MCP-1-induced Pyk2 tyrosine phosphorylation is controlled by the Src family kinase. We also report, in this study, that PKCβ, an isoform of PKC, is required for both Src and Pyk2 activation/phosphorylation in response to MCP-1 stimulation. We identified Lyn as the specific Src kinase isoform that is activated by MCP-1 and acts upstream of Pyk2 in primary monocytes. Furthermore, Lyn is found to be indispensable for monocyte migration in response to MCP-1 stimulation. Moreover, our coimmunoprecipitation studies in monocytes revealed that PKCβ, Pyk2, and Lyn exist constitutively in a molecular complex. To our knowledge, our study has uncovered a novel PKCβ-Lyn-Pyk2 signaling cascade in primary monocytes that regulates MCP-1-induced monocyte adhesion and migration.

Fecal microbiota composition associates with the capacity of human peripheral blood monocytes to differentiate into immunogenic dendritic cells in vitro

ABSTRACT Although promising for active immunization in cancer patients, dendritic cells (DCs) vaccines generated in vitro display high inter-individual variability in their immunogenicity, which mostly limits their therapeutic efficacy. Gut microbiota composition is a key emerging factor affecting individuals’ immune responses, but it is unknown how it affects the variability of donors’ precursor cells to differentiate into immunogenic DCs in vitro. By analyzing gut microbiota composition in 14 healthy donors, along with the phenotype and cytokines production by monocyte-derived DCs, we found significant correlations between immunogenic properties of DC and microbiota composition. Namely, donors who had higher α-diversity of gut microbiota and higher abundance of short-chain fatty acid (SCFAs) and SCFA-producing bacteria in feces, displayed lower expression of CD1a on immature (im)DC and higher expression of ILT-3, costimulatory molecules (CD86, CD40) proinflammatory cytokines (TNF-α, IL-6, IL-8) and IL-12p70/IL-10 ratio, all of which correlated with their lower maturation potential and immunogenicity upon stimulation with LPS/IFNγ, a well-known Th1 polarizing cocktail. In contrast, imDCs generated from donors with lower α-diversity and higher abundance of Bifidobacterium and Collinsella in feces displayed higher CD1a expression and higher potential to up-regulate CD86 and CD40, increase TNF-α, IL-6, IL-8 production, and IL-12p70/IL-10 ratio upon stimulation. These results emphasize the important role of gut microbiota on the capacity of donor precursor cells to differentiate into immunogenic DCs suitable for cancer therapy, which could be harnessed for improving the actual and future DC-based cancer therapies.