ICAM-1 regulates macrophage polarization by suppressing MCP-1 expression via miR-124 upregulation

Stem Cells from Human Exfoliated Deciduous Teeth-Derived Exosomes for the Treatment of Acute Liver Injury and Liver Fibrosis

Mesenchymal stem cells (MSCs) play a crucial role in regenerative medicine due to their regenerative potential. However, traditional MSC-based therapies are hindered by issues such as microvascular obstruction and low cell survival after transplantation. Exosomes derived from MSCs (MSC-Exo) provide a cell-free, nanoscale alternative, mitigating these risks and offering therapeutic potential for liver diseases. Nonetheless, the functional variability of MSCs from different sources complicates their clinical application. Stem cells derived from human exfoliated deciduous teeth (SHED) offer advantages such as ease of procurement and robust proliferative capacity, but their secretome, particularly SHED-Exo, remains underexplored in the context of liver disease therapy. This study analyzed MSC-Exo from various sources via small RNA sequencing to identify differences in microRNA profiles, aiding in the selection of optimal MSC sources for clinical use. SHED-Exo was subsequently tested in an acute liver injury model, showing notable regenerative effects, including enhanced hepatocyte proliferation, macrophage polarization, and reduced inflammation. Despite strong liver-targeting properties, the rapid hepatic clearance of SHED-Exo limits its effectiveness in chronic liver diseases. To address this challenge, a GelMA-based hydrogel was developed for in situ delivery, ensuring sustained release and enhanced antifibrotic efficacy, providing a promising strategy for chronic liver disease management.

Periarticular myositis and muscle fibrosis are cytokine-dependent complications of inflammatory arthritis

The deleterious consequences of chronic synovitis on cartilage, tendon, and bone in rheumatoid arthritis (RA) are well described. In contrast, its effects on periarticular skeletal muscle are under-studied. Furthermore, while TNF inhibition is an effective therapy for RA synovitis, it exacerbates fibrosis in muscle injury models. We aimed to investigate whether myositis and muscle fibrosis are features of inflammatory arthritis and evaluate whether targeted RA therapies influence these disease features. Periarticular muscle was analyzed in murine models of poly- and monoarticular inflammatory arthritis: serum transfer-induced arthritis, collagen-induced arthritis, K/BxN, and antigen-induced arthritis (AIA). Periarticular myositis and an increase in muscle fibroadipocyte progenitors (FAPs) were observed in all models, despite diverse arthritogenic mechanisms. Periarticular muscle fibrosis was observed from day 15 in AIA. Neither etanercept nor baricitinib suppressed periarticular myositis or subsequent fibrosis compared to vehicle, despite reducing arthritis. Notably, etanercept failed to prevent muscle fibrosis even when initiated early, but this was not linked to increased FAP survival or collagen production. Corroborating these data, radiographic and histological analyses revealed periarticular myositis in patients with RA. We conclude that periarticular myositis and fibrosis are under-recognized features of inflammatory arthritis. Targeted RA therapies may not prevent periarticular muscle sequelae, despite controlling arthritis.

Trimethylamine N-oxide aggravates human aortic valve interstitial cell inflammation by regulating the macrophages polarization through a N6-methyladenosine-mediated pathway

BACKGROUND

Trimethylamine N-oxide (TMAO) is a gut microbial metabolite that promotes calcified aortic valve disease (CAVD), but the underlying mechanism remains obscure. Herein, we aim to test the hypothesis that TMAO regulated the inflammatory process in aortic valves via N6-methyladenosine (m6A) RNA methylation-mediated macrophage polarization.

METHODS

In vitro, we stimulated macrophages (Phorbol-12-Myristate-13-Acetate-induced THP-1) with TMAO and assessed the expression of methyltransferase-like 3 (Mettl3), IL-1 receptor associated kinase M (IRAK-M) and polarization markers. The interaction between YTH domain family protein 2 (YTHDF2) and IRAK-M mRNA was explored by RNA-IP and RNA decay assay. Functionally, the effects of macrophages on human aortic valve interstitial cells (AVICs) were measured via macrophage adhesion assay and co-culture system. In vivo, the influence of IRAK-M on CAVD development was verified using Irak-m-/- mice.

RESULT

Mettl3 was highly expressed while IRAK-M was decreased in human calcified aortic valves. In vitro, TMAO upregulated the expression of Mettl3, while the expression of IRAK-M, an important negative regulator of the NF-κB pathway, was remarkably decreased in macrophages. TMAO also induced classical macrophage activation (M1 polarization). Mechanistically, IRAK-M was identified as a target of Mettl3-mediated m6A modification, indicating the involvement of m6A methylation in the regulation of NF-κB activation. Moreover, RIP assay revealed the direct interaction between YTHDF2 and IRAK-M mRNA and this process was dependent on Mettl3. TMAO-treated macrophage conditioned medium induced inflammatory responses in human aortic valve interstitial cells (AVICs). In vivo experiments showed that the deletion of IRAK-M significantly accelerated the progression of aortic valve lesion in mice administrated with high-fat and choline diet (HFCD).

CONCLUSION

TMAO induces the expression of Mettl3 in macrophages. Mettl3 promotes M1 polarization of macrophages by inhibiting IRAK-M through a m6A/YTHDF2 pathway. TMAO-treated macrophages aggravate the inflammation of human AVICs.

The effect of cancer cell-derived exosomal proteins on macrophage polarization: An in-depth review

Cancer is characterized by unregulated cell proliferation, enabling it to invade and spread to different organs and tissues in the body. Cancer progression is intricately influenced by the complex dynamics within the tumor microenvironment (TME). The TME is a composite and dynamic network comprising cancer cells and various immune cells, including tumor-associated macrophages. Exosomes facilitate the communication between different cancer cells as well as other types of cells. This review particularly focuses on exosomal proteins derived from different cancer cells in mounting the complex crosstalk between cells of cancer and macrophages within the TME. Most cancer-derived exosomal proteins polarize macrophages towards M2 phenotype, promoting cancer aggressiveness, while a few have role switching towards the M1 phenotype, inhibiting cancer proliferation, respectively. In this review, we summarize, for the first time, the dual impact of cancer cell-derived exosomal proteins on macrophage polarization and the associated signaling pathways, offering valuable insights for developing innovative therapeutic strategies against diverse cancer types.

Single-cell RNA-sequencing analysis of immune and mesenchymal cell crosstalk in the developing enthesis

Autoimmunity underlies many painful disorders, such as enthesopathies, which localize to the enthesis. From infiltration of the synovium and axial skeleton by B cells, to disturbances in the ratio of M1/M2 enthesis macrophages, to CD8 + T cell mediated inflammation, autoimmune dysregulation is becoming increasingly well characterized in enthesopathies. Tissue resident B cells, macrophages, neutrophils, and T cells have also been localized in healthy human entheses. However, the potential developmental origins, presence, and role of immune cells (ICs) in enthesis development is not known. Here, we use single-cell RNA-sequencing analysis to describe IC subtypes present in the enthesis before, during, and after mineralization, and to infer regulatory interactions between ICs and mesenchymal cells (MCs). We report the presence of nine phenotypically distinct IC subtypes, including B cells, macrophages, neutrophils, and T cells. We find that specific IC subtypes may promote MC-proliferation and differentiation, and that MCs may regulate IC phenotype and autoimmunity. Our findings suggest that bidirectional regulatory interactions between ICs and MCs may be important to enthesis mineralization, and suggest that progenitor MCs have a unique ability to limit autoimmunity during development.

Intercellular Adhesion Molecule 1 (ICAM-1): An Inflammatory Regulator with Potential Implications in Ferroptosis and Parkinson's Disease

Intercellular adhesion molecule 1 (ICAM-1/CD54), a transmembrane glycoprotein, has been considered as one of the most important adhesion molecules during leukocyte recruitment. It is encoded by the ICAM1 gene and plays a central role in inflammation. Its crucial role in many inflammatory diseases such as ulcerative colitis and rheumatoid arthritis are well established. Given that neuroinflammation, underscored by microglial activation, is a key element in neurodegenerative diseases such as Parkinson's disease (PD), we investigated whether ICAM-1 has a role in this progressive neurological condition and, if so, to elucidate the underpinning mechanisms. Specifically, we were interested in the potential interaction between ICAM-1, glial cells, and ferroptosis, an iron-dependent form of cell death that has recently been implicated in PD. We conclude that there exist direct and indirect (via glial cells and T cells) influences of ICAM-1 on ferroptosis and that further elucidation of these interactions can suggest novel intervention for this devastating disease.

Integration of single-cell RNA sequencing of endothelial cells and proteomics to unravel the role of ICAM1-PTGS2 communication in apical periodontitis: A laboratory investigation

AIM

Endothelial cells (EDs) play a key role in angiogenesis and are associated with granulomatous lesions in patients with chronic apical periodontitis (CAP). This study aimed to investigate the diversity of EDs using single-cell ribonucleic acid sequencing (scRNA-seq) and to evaluate the regulation of intercellular adhesion molecule 1 (ICAM1) on the ferroptosis-related protein, prostaglandin-endoperoxide synthase 2 (PTGS2), in CAP.

METHODOLOGY

EDs from the uploaded scRNA-seq data of five CAP samples (GSE181688 and GSE197680) were categorized using distinct marker genes. The interactions between vein EDs (veinEndo) and other cell types were analysed using CellPhoneDB. Differentially expressed proteins in the proteomics of human umbilical vein EDs (HUVECs) and THP-1-derived macrophages infected with Porphyromonas gingivalis were compared with the differentially expressed genes (DEGs) of VeinEndo in scRNA-seq of CAP versus healthy control periodontal tissues. The protein-protein interaction of ICAM1-PTGS2 in macrophages and HUVECs was validated by adding recombinant ICAM1, ICAM1 inhibitor and PTGS2 inhibitor using real-time polymerase chain reaction (PCR), western blotting, and immunofluorescence staining.

RESULTS

EDs in patients with CAP were divided into eight subclusters: five vein ED, capillaries, arterials and EC (PLA). There were 29 mutually upregulated DEGs and two mutually downregulated DEGs in vein cells in the scRNA-seq data, as well as differentially expressed proteins in the proteomics of HUVECs. Real-time PCR and immunofluorescence staining showed that ICAM1 and PTGS2 were highly expressed in CAP, infected HUVECs, and macrophages. Recombinant protein ICAM1 may improve PTGS2 expression, reactive oxygen species (ROS), and Fe2+ levels and decrease glutathione peroxidase 4 (GPX4) and SLC7A11 protein levels. ICAM1 inhibitor may inverse the above changes.

CONCLUSIONS

scRNA-seq revealed the diversity of EDs in CAP and identified the possible regulation of ICAM1 by the ferroptosis-related protein, PTGS2, in infected HUVECs and macrophages, thus providing a basis for therapeutic approaches that target the inflammatory microenvironment of CAP.

Macrophage AHR-TLR4 cross-talk drives p-STAT3 (Ser727)-mediated mitochondrial oxidative stress and upregulates IDO/ICAM-1 in the steatohepatitis induced by aflatoxin B1

Aflatoxin B1 (AFB1) is a major mycotoxin contaminant showing in the environment and foods. In this study, the molecular initiating events (MIEs) of AFB1-induced steatohepatitis were explored in mice and human cell model. We observed dose-dependent steatohepatitis in the AFB1-treated mice, including triglyceride accumulation, fibrotic collagen secretion, enrichment of CD11b + and F4/80+ macrophages/Kupffer cells, cell death, lymphocytes clusters and remarkable atrophy areas. The gut barrier and gut-microbiota were also severely damaged after the AFB1 treatment and pre-conditioned colitis in the experimental mice aggravated the steatohepatitis phenotypes. We found that macrophages cells can be pro-inflammatorily activated to M1-like phenotype by AFB1 through an AHR/TLR4/p-STAT3 (Ser727)-mediated mitochondrial oxidative stress. The phenotypes can be rescued by AHR inhibitors in the mice model and human cell model. We further showed that this signaling axis is based on the cross-talk interaction between AHR and TLR4. Gene knock-up experiment found that the signaling is dependent on AFB1 ligand-binding with AHR, but not protein expressions of TLR4. The signaling elevated NLRP3 and two immune metabolic enzymes ICAM-1 and IDO that are associated with macrophage polarization. Results from intervention experiments with natural anti-oxidant and AHR inhibitor CH223191 suggest that the macrophage polarization may rely on AHR and ROS. Our study provides novel and critical references to the food safety and public health regulation of AFB1.

The potential role of miRNA in regulating macrophage polarization

Macrophage polarization is a dynamic process determining the outcome of various physiological and pathological situations through inducing pro-inflammatory responses or resolving inflammation via exerting anti-inflammatory effects. The miRNAs are epigenetic regulators of different biologic pathways that target transcription factors and signaling molecules to promote macrophage phenotype transition and regulate immune responses. Modulating the macrophage activation, differentiation, and polarization by miRNAs is crucial for immune responses in response to microenvironmental signals and under various physiological and pathological conditions. In term of clinical significance, regulating macrophage polarization via miRNAs could be utilized for inflammation control. Also, understanding the role of miRNAs in macrophage polarization can provide insights into diagnostic strategies associated with dysregulated miRNAs and for developing macrophage-centered therapeutic methods. In this case, targeting miRNAs to further regulate of macrophage polarization may become an efficient strategy for treating immune-associated disorders. The current review investigated and categorized various miRNAs directly or indirectly involved in macrophage polarization by targeting different transcription factors and signaling pathways. In addition, prospects for regulating macrophage polarization via miRNA as a therapeutic choice that could be implicated in various pathological conditions, including cancer or inflammation-mediated injuries, were discussed.

Complementary CRISPR screen highlights the contrasting role of membrane-bound and soluble ICAM-1 in regulating antigen-specific tumor cell killing by cytotoxic T cells

Cytotoxic CD8 +T lymphocytes (CTLs) are key players of adaptive anti-tumor immunity based on their ability to specifically recognize and destroy tumor cells. Many cancer immunotherapies rely on unleashing CTL function. However, tumors can evade killing through strategies which are not yet fully elucidated. To provide deeper insight into tumor evasion mechanisms in an antigen-dependent manner, we established a human co-culture system composed of tumor and primary immune cells. Using this system, we systematically investigated intrinsic regulators of tumor resistance by conducting a complementary CRISPR screen approach. By harnessing CRISPR activation (CRISPRa) and CRISPR knockout (KO) technology in parallel, we investigated gene gain-of-function as well as loss-of-function across genes with annotated function in a colon carcinoma cell line. CRISPRa and CRISPR KO screens uncovered 187 and 704 hits, respectively, with 60 gene hits overlapping between both. These data confirmed the role of interferon-γ (IFN-γ), tumor necrosis factor α (TNF-α) and autophagy pathways and uncovered novel genes implicated in tumor resistance to killing. Notably, we discovered that ILKAP encoding the integrin-linked kinase-associated serine/threonine phosphatase 2 C, a gene previously unknown to play a role in antigen specific CTL-mediated killing, mediate tumor resistance independently from regulating antigen presentation, IFN-γ or TNF-α responsiveness. Moreover, our work describes the contrasting role of soluble and membrane-bound ICAM-1 in regulating tumor cell killing. The deficiency of membrane-bound ICAM-1 (mICAM-1) or the overexpression of soluble ICAM-1 (sICAM-1) induced resistance to CTL killing, whereas PD-L1 overexpression had no impact. These results highlight the essential role of ICAM-1 at the immunological synapse between tumor and CTL and the antagonist function of sICAM-1.

Subway station dust-induced pulmonary inflammation may be due to the dysfunction of alveolar macrophages: Possible contribution of bound elements

With its increasing value as a means of public transportation, the health effects of the air in subway stations have attracted public concern. In the current study, we investigated the pulmonary toxicity of dust collected from an air purifier installed on the platform of the busiest subway station in Seoul. We found that the dust contained various elements which are attributable to the facilities and equipment used to operate the subway system. Particularly, iron (Fe), chromium (Cr), zirconium (Zr), barium (Ba), and molybdenum (Mo) levels were more notable in comparison with those in dust collected from the ventilation chamber of a subway station. To explore the health effects of inhaled dust, we first instilled via the trachea in ICR mice for 13 weeks. The total number of pulmonary macrophages increased significantly with the dose, accompanying hematological changes. Dust-laden alveolar macrophages and inflammatory cells accumulated in the perivascular regions in the lungs of the treated mice, and pulmonary levels of CXCL-1, TNF-α, and TGF-β increased clearly compared with the control. The CCR5 and CD54 level expressed on BAL cell membranes was also enhanced following exposure to dust, whereas the CXCR2 level tended to decrease in the same samples. In addition, we treated the dust to alveolar macrophages (known as dust cells), lysosomal and mitochondrial function decreased, accompanied by cell death, and NO production was rapidly elevated with concentration. Moreover, the expression of autophagy- (p62) and anti-oxidant (SOD-2)-related proteins increased, and the expression of inflammation-related genes was dramatically up-regulated in the dust-treated cells. Therefore, we suggest that dysfunction of alveolar macrophages may importantly contribute to dust-induced inflammatory responses and that the exposure concentrations of Cr, Fe, Mo, Zr, and Ba should be considered carefully when assessing the health risks associated with subway dust. We also hypothesize that the bound elements may contribute to dust-induced macrophage dysfunction by inhibiting viability.

Role of macrophage AHR/TLR4/STAT3 signaling axis in the colitis induced by non-canonical AHR ligand aflatoxin B1

Here we report that macrophage AHR/TLR/STAT signaling axis is implicated in the colon colitis induced by non-canonical AHR ligand aflatoxin B1 (AFB1). In BALB/c mice gavaged with 5, 25 and 50 µg/kg body weight/day AFB1, we observed severe colitis featured by over-recruitment of myeloid lineage immune cells such as monocytes/macrophage in colon lamina propria. Stressed and damaged colon epithelial cells were observed in low-dose group, while twisted and shortened intestinal crypts being found in middle dose group. Severe tissue damage was induced in the high-dose group. Dose-dependent increases of ROS, NO, and decrease of mitochondrial ROS-suppressor STAT3 were observed in the exposure groups. Further investigation in AFB1-treated human macrophage model found: (1) functional adaptations such as elevation of TNF-alpha and IL-6 secretion, stimulation of phagocytosis, elevation of LTE4 level; (2) overall inflammatory status confirmed by RNA-sequence analysis, in line with up-regulation of immune functional proteins such as ICAM-1, IDO-1, NF-kB-p65, NLRP3, COX-2 and iNOS; (3) mRNA disruption of mitochondrial oxidative phosphorylation complex I units and STATs; (4) perturbation of AHR/TLR/STAT3 signaling axis, including elevated AHR, TLR2, TLR4, and decreased STAT3, p-STAT3 Ser727. Mechanism investigation revealed regulatory links of ligand-dependent AHR/TLR4/STAT3. AHR-TLR4 together regulate MyD88, and STAT3 may be directly regulated by MyD88 (TLR4 downstream molecule) upon AHR/TLR4 binding with ligands. Solely protein level changes of AHR/TLR4 cannot regulate STAT3. Our study suggests that macrophage AHR/TLR4/STAT3 is involved with the colitis induced by sub-acute exposure to AFB1. Future follow-up study will focus on the intervention of the colitis using AHR-anti-inflammatory ligands.

CAGE sequencing reveals CFTR-dependent dysregulation of type I IFN signaling in activated cystic fibrosis macrophages

An intense, nonresolving airway inflammatory response leads to destructive lung disease in cystic fibrosis (CF). Dysregulation of macrophage immune function may be a key facet governing the progression of CF lung disease, but the underlying mechanisms are not fully understood. We used 5' end centered transcriptome sequencing to profile P. aeruginosa LPS-activated human CF macrophages, showing that CF and non-CF macrophages deploy substantially distinct transcriptional programs at baseline and following activation. This includes a significantly blunted type I IFN signaling response in activated patient cells relative to healthy controls that was reversible upon in vitro treatment with CFTR modulators in patient cells and by CRISPR-Cas9 gene editing to correct the F508del mutation in patient-derived iPSC macrophages. These findings illustrate a previously unidentified immune defect in human CF macrophages that is CFTR dependent and reversible with CFTR modulators, thus providing new avenues in the search for effective anti-inflammatory interventions in CF.

Intercellular Adhesion Molecule 1: More than a Leukocyte Adhesion Molecule

Intercellular adhesion molecule 1 (ICAM-1) is a transmembrane protein in the immunoglobulin superfamily expressed on the surface of multiple cell populations and upregulated by inflammatory stimuli. It mediates cellular adhesive interactions by binding to the β2 integrins macrophage antigen 1 and leukocyte function-associated antigen 1, as well as other ligands. It has important roles in the immune system, including in leukocyte adhesion to the endothelium and transendothelial migration, and at the immunological synapse formed between lymphocytes and antigen-presenting cells. ICAM-1 has also been implicated in the pathophysiology of diverse diseases from cardiovascular diseases to autoimmune disorders, certain infections, and cancer. In this review, we summarize the current understanding of the structure and regulation of the ICAM1 gene and the ICAM-1 protein. We discuss the roles of ICAM-1 in the normal immune system and a selection of diseases to highlight the breadth and often double-edged nature of its functions. Finally, we discuss current therapeutics and opportunities for advancements.

Murine macrophage-based iNos reporter reveals polarization and reprogramming in the context of breast cancer

As part of the first line of defense against pathogens, macrophages possess the ability to differentiate into divergent phenotypes with varying functions. The process by which these cells change their characteristics, commonly referred to as macrophage polarization, allows them to change into broadly pro-inflammatory (M1) or anti-inflammatory (M2) subtypes, and depends on the polarizing stimuli. Deregulation of macrophage phenotypes can result in different pathologies or affect the nature of some diseases, such as cancer and atherosclerosis. Therefore, a better understanding of macrophage phenotype conversion in relevant models is needed to elucidate its potential roles in disease. However, there are few existing probes to track macrophage changes in multicellular environments. In this study, we generated an eGFP reporter cell line based on inducible nitric oxide synthase (iNos) promoter activity in RAW264.7 cells (RAW:iNos-eGFP). iNos is associated with macrophage activation to pro-inflammatory states and decreases in immune-suppressing ones. We validated the fidelity of the reporter for iNos following cytokine-mediated polarization and confirmed that reporter and parental cells behaved similarly. RAW:iNos-eGFP cells were then used to track macrophage responses in different in vitro breast cancer models, and their re-education from anti- to pro-inflammatory phenotypes via a previously reported pyrimido(5,4-b)indole small molecule, PBI1. Using two mouse mammary carcinoma cell lines, 4T1 and EMT6, effects on macrophages were assessed via conditioned media, two-dimensional/monolayer co-culture, and three-dimensional spheroid models. While conditioned media derived from 4T1 or EMT6 cells and monolayer co-cultures of each cancer cell line with RAW:iNos-eGFP cells all resulted in decreased fluorescence, the trends and extents of effects differed. We also observed decreases in iNos-eGFP signal in the macrophages in co-culture assays with 4T1- or EMT6-based spheroids. We then showed that iNos production is enhanced in these cancer models using PBI1, tracking increased fluorescence. Collectively, this work demonstrates that this reporter-based approach provides a facile means to study macrophage responses in complex, multicomponent environments. Beyond the initial studies presented here, this platform can be used with a variety of in vitro models and extended to in vivo applications with intravital imaging.

MicroRNA-124 expression in Kupffer cells modulates liver injury by targeting IL-6/STAT3 signaling

MicroRNA-124 (miR-124) is related to liver injury due to chronic hepatitis B (CHB) and hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF). However, the mechanism whereby miR-124 regulates liver inflammation remains unknown. In this study, we show that serum miR-124 serves as a compensatory predictive factor for organ failure and the 28-day prognosis of patients with HBV-ACLF. Moreover, within a mouse model of concanavalin A-induced acute liver injury, miR-124 is highly expressed in Kupffer cells. Overexpression of miR-124 significantly decreases interleukin-6 (IL-6) secretion, and relieves pathological liver necrosis to a great extent. Mechanistically, miR-124 directly targets the 3'-untranslated region of signal transducer and activator of transcription 3 (STAT3) and inhibits IL-6/STAT3 signaling, which reduces pro-inflammatory Kupffer cell polarization. Collectively, our findings suggest that miR-124 can potentially serve as a predictive biomarker for HBV-ACLF prognosis and may represent a promising therapeutic target for relieving severe liver injury resulting from cytokine storms.

Specialized functions and sexual dimorphism explain the functional diversity of the myeloid populations during glioma progression

Malignant gliomas are aggressive, hard-to-treat brain tumors. Their tumor microenvironment is massively infiltrated by myeloid cells, mostly brain-resident microglia, bone marrow (BM)-derived monocytes/macrophages, and dendritic cells that support tumor progression. Single-cell omics studies significantly dissected immune cell heterogeneity, but dynamics and specific functions of individual subpopulations were poorly recognized. We use Cellular Indexing of Transcriptomes and Epitopes by sequencing (CITE-seq) to precisely dissect myeloid cell identities and functionalities in murine GL261 gliomas. We demonstrate that the diversity of myeloid cells infiltrating gliomas is dictated by cell type and cell state. Glioma-activated microglia are the major source of cytokines attracting other immune cells, whereas BM-derived cells show the monocyte-to-macrophage transition in the glioma microenvironment. This transition is coupled with a phenotypic switch from the IFN-related to antigen-presentation and tumor-supportive gene expression. Moreover, we found sex-dependent differences in transcriptional programs and composition of myeloid cells in murine and human glioblastomas.

Sorbitol dehydrogenase induction of cancer cell necroptosis and macrophage polarization in the HCC microenvironment suppresses tumor progression

Hepatocellular carcinoma (HCC) is among the most common malignant cancers worldwide, with an increasing incidence associated with an increase in deaths due to liver cancer. HCC is typically detected at an advanced stage in patients with underlying liver dysfunction, resulting in high mortality. The identification of HCC-specific targets represents a desired but unmet need for liver cancer treatment. To identify potentially novel HCC therapeutic targets, we performed a secretome analysis using HCC spheroids. Sorbitol dehydrogenase (SORD) was identified as uniquely enriched in the secretomes and lysates derived from HCC spheroids, and high SORD expression in HCC tissues was associated with favorable effects on overall survival among patients with liver cancer. We found that the introduction of excess SORD in HCC cells inhibited tumor growth and stemness by enhancing necroptosis signal and bypassing energy-yielding pathways through regulation of lactate dehydrogenase A (LDHA) expression and mitochondrial dynamics. Treatment with human recombinant SORD (hrSORD) controlled HCC cell growth and regulated macrophage polarization in the tumor microenvironment. These results demonstrate that SORD plays critical functional roles in HCC suppression through polyol pathway-independent mechanisms, suggesting that targeting SORD expression might represent a promising therapeutic strategy for liver cancer therapy.

Transcriptomic Regulation of Macrophages by Matrix-Bound Nanovesicle-Associated Interleukin-33

The innate immune response, particularly the phenotype of responding macrophages, has significant clinical implications in the remodeling outcome following implantation of biomaterials and engineered tissues. In general, facilitation of an anti-inflammatory (M2-like) phenotype is associated with tissue repair and favorable outcomes, whereas pro-inflammatory (M1-like) activation can contribute to chronic inflammation and a classic foreign body response. Biologic scaffolds composed of extracellular matrix (ECM) and, more recently, matrix-bound nanovesicles (MBV) embedded within the ECM are known to direct macrophages toward an anti-inflammatory phenotype and stimulate a constructive remodeling outcome. The mechanisms of MBV-mediated macrophage activation are not fully understood, but interleukin-33 (IL-33) within the MBV appears critical for M2-like activation. Previous work has shown that IL-33 is encapsulated within the lumen of MBV and stimulates phenotypical changes in macrophages independent of its canonical surface receptor stimulation-2 (ST2). In the present study, we used next-generation RNA sequencing to determine the gene signature of macrophages following exposure to MBV with and without intraluminal IL-33. MBV-associated IL-33 instructed an anti-inflammatory phenotype in both wild-type and st2-/- macrophages by upregulating M2-like and downregulating M1-like genes. The repertoire of genes regulated by ST2-independent IL-33 signaling were broadly related to the inflammatory response and crosstalk between cells of both the innate and adaptive immune systems. These results signify the importance of the MBV intraluminal protein IL-33 in stimulating a pro-remodeling M2-like phenotype in macrophages and provides guidance for the designing of next-generation biomaterials and tissue engineering strategies. Impact statement The phenotype of responding macrophages is predictive of the downstream remodeling response to an implanted biomaterial. The clinical impact of macrophage phenotype has motivated studies to investigate the factors that regulate macrophage activation. Matrix-bound nanovesicles (MBV) embedded within the extracellular matrix direct macrophages toward an anti-inflammatory (M2)-like phenotype that is indicative of a favorable remodeling response. Although the mechanisms of MBV-mediated macrophage activation are not fully understood, the intraluminal protein interleukin-33 (IL-33) is clearly a contributing signaling molecule. The present study identifies those genes regulated by MBV-associated IL-33 that promote a pro-remodeling M2-like macrophage activation state and can guide future therapies in regenerative medicine.

Modelling aggressive prostate cancers of young men in immune-competent mice, driven by isogenic Trp53 alterations and Pten loss

Understanding prostate cancer onset and progression in order to rationally treat this disease has been critically limited by a dire lack of relevant pre-clinical animal models. We have generated a set of genetically engineered mice that mimic human prostate cancer, initiated from the gland epithelia. We chose driver gene mutations that are specifically relevant to cancers of young men, where aggressive disease poses accentuated survival risks. An outstanding advantage of our models are their intact repertoires of immune cells. These mice provide invaluable insight into the importance of immune responses in prostate cancer and offer scope for studying treatments, including immunotherapies. Our prostate cancer models strongly support the role of tumour suppressor p53 in functioning to critically restrain the emergence of cancer pathways that drive cell cycle progression; alter metabolism and vasculature to fuel tumour growth; and mediate epithelial to mesenchymal-transition, as vital to invasion. Importantly, we also discovered that the type of p53 alteration dictates the specific immune cell profiles most significantly disrupted, in a temporal manner, with ramifications for disease progression. These new orthotopic mouse models demonstrate that each of the isogenic hotspot p53 amino acid mutations studied (R172H and R245W, the mouse equivalents of human R175H and R248W respectively), drive unique cellular changes affecting pathways of proliferation and immunity. Our findings support the hypothesis that individual p53 mutations confer their own particular oncogenic gain of function in prostate cancer.

The Scientific Rationale for the Introduction of Renalase in the Concept of Cardiac Fibrosis

Cardiac fibrosis represents a redundant accumulation of extracellular matrix proteins, resulting from a cascade of pathophysiological events involved in an ineffective healing response, that eventually leads to heart failure. The pathophysiology of cardiac fibrosis involves various cellular effectors (neutrophils, macrophages, cardiomyocytes, fibroblasts), up-regulation of profibrotic mediators (cytokines, chemokines, and growth factors), and processes where epithelial and endothelial cells undergo mesenchymal transition. Activated fibroblasts and myofibroblasts are the central cellular effectors in cardiac fibrosis, serving as the main source of matrix proteins. The most effective anti-fibrotic strategy will have to incorporate the specific targeting of the diverse cells, pathways, and their cross-talk in the pathogenesis of cardiac fibroproliferation. Additionally, renalase, a novel protein secreted by the kidneys, is identified. Evidence demonstrates its cytoprotective properties, establishing it as a survival element in various organ injuries (heart, kidney, liver, intestines), and as a significant anti-fibrotic factor, owing to its, in vitro and in vivo demonstrated pleiotropy to alleviate inflammation, oxidative stress, apoptosis, necrosis, and fibrotic responses. Effective anti-fibrotic therapy may seek to exploit renalase’s compound effects such as: lessening of the inflammatory cell infiltrate (neutrophils and macrophages), and macrophage polarization (M1 to M2), a decrease in the proinflammatory cytokines/chemokines/reactive species/growth factor release (TNF-α, IL-6, MCP-1, MIP-2, ROS, TGF-β1), an increase in anti-apoptotic factors (Bcl2), and prevention of caspase activation, inflammasome silencing, sirtuins (1 and 3) activation, and mitochondrial protection, suppression of epithelial to mesenchymal transition, a decrease in the pro-fibrotic markers expression (’α-SMA, collagen I, and III, TIMP-1, and fibronectin), and interference with MAPKs signaling network, most likely as a coordinator of pro-fibrotic signals. This review provides the scientific rationale for renalase’s scrutiny regarding cardiac fibrosis, and there is great anticipation that these newly identified pathways are set to progress one step further. Although substantial progress has been made, indicating renalase’s therapeutic promise, more profound experimental work is required to resolve the accurate underlying mechanisms of renalase, concerning cardiac fibrosis, before any potential translation to clinical investigation.

The Chemopreventive Effects of Polyphenols and Coffee, Based upon a DMBA Mouse Model with microRNA and mTOR Gene Expression Biomarkers

Polyphenols are capable of decreasing cancer risk. We examined the chemopreventive effects of a green tea (Camellia sinensis) extract, polyphenol extract (a mixture of blackberry (Rubus fruticosus), blackcurrants (Ribes nigrum), and added resveratrol phytoalexin), Chinese bayberry (Myrica rubra) extract, and a coffee (Coffea arabica) extract on 7,12-dimethylbenz[a]anthracene (DMBA) carcinogen-increased miR-134, miR-132, miR-124-1, miR-9-3, and mTOR gene expressions in the liver, spleen, and kidneys of CBA/Ca mice. The elevation was quenched significantly in the organs, except for miR-132 in the liver of the Chinese bayberry extract-consuming group, and miR-132 in the kidneys of the polyphenol-fed group. In the coffee extract-consuming group, only miR-9-3 and mTOR decreased significantly in the liver; also, miR-134 decreased significantly in the spleen, and, additionally, miR-124-1 decreased significantly in the kidney. Our results are supported by literature data, particularly the DMBA generated ROS-induced inflammatory and proliferative signal transducers, such as TNF, IL1, IL6, and NF-κB; as well as oncogenes, namely RAS and MYC. The examined chemopreventive agents, besides the obvious antioxidant and anti-inflammatory effects, mainly blocked the mentioned DMBA-activated factors and the mitogen-activated protein kinase (MAPK) as well, and, at the same time, induced PTEN as well as SIRT tumor suppressor genes.

Pathophysiology of Atherosclerosis

Atherosclerosis is the main risk factor for cardiovascular disease (CVD), which is the leading cause of mortality worldwide. Atherosclerosis is initiated by endothelium activation and, followed by a cascade of events (accumulation of lipids, fibrous elements, and calcification), triggers the vessel narrowing and activation of inflammatory pathways. The resultant atheroma plaque, along with these processes, results in cardiovascular complications. This review focuses on the different stages of atherosclerosis development, ranging from endothelial dysfunction to plaque rupture. In addition, the post-transcriptional regulation and modulation of atheroma plaque by microRNAs and lncRNAs, the role of microbiota, and the importance of sex as a crucial risk factor in atherosclerosis are covered here in order to provide a global view of the disease.

Macrophages Protect Endometriotic Cells Against Oxidative Damage Through a Cross-Talk Mechanism

This aim of this study was to investigate whether macrophages protect endometriotic cells from oxidative injury and to elucidate the underlying mechanisms of any protection. Endometriotic cells cultured with or without differentiated macrophages (dTHP-1 cells) were treated with hydrogen peroxide (H₂O₂) or methemoglobin, a major component of hemoglobin species in endometriotic cyst fluid. Co-culture experiments, microarray analysis, screening and validation of differentially expressed genes (DEGs), cell proliferation and viability assays, and experiments using a specific inhibitor were conducted to investigate the functional cross-talk between endometriotic cells and macrophages. Microarray analysis revealed that endometriotic cells co-cultured with dTHP-1 differentially express several genes compared with monoculture. Quantitative enzyme-linked immunosorbent assay (ELISA) and Western blotting analysis identified TGF-β1 as a promising candidate gene expressed in endometriotic cells co-cultured with dTHP-1 cells. TGF-β1 stimulated the expression of heme oxygenase-1 (HO-1) in dTHP-1 cells. HO-1 expression was increased in dTHP-1 cells co-cultured with endometriotic cells compared with the dTHP-1 monoculture. Both H₂O₂ and methemoglobin upregulated the expression of the HO-1 protein in the dTHP-1 monoculture; moreover, co-culture with endometriotic cells further enhanced HO-1 production. The co-culture with dTHP-1 protected endometriotic cells against oxidative injury. Blockade of HO-1 abolished the protective effects of macrophages. In an oxidative stress environment, TGF-β1 produced by endometriotic cells may protect against oxidative injury through the upregulation of macrophage-derived HO-1. The cross-talk between endometriotic cells and macrophages may contribute to the progression and pathogenesis of endometriosis.

A transcriptomic analysis of neuropathic pain in the anterior cingulate cortex after nerve injury

The anterior cingulate cortex (ACC) is a core brain region processing pain emotion. In this study, we performed RNA sequencing analysis to reveal transcriptomic profiles of the ACC in a rat chronic constriction injury (CCI) model. A total of 1628 differentially expressed genes (DEGs) were identified by comparing sham-operated rats with rats of 12 hours, 1, 3, 7, and 14 days after surgery, respectively. Although these inflammatory-related DEGs were generally increased after CCI, different kinetics of time-series expression were observed with the development of neuropathic pain affection. Specifically, the expression of Ccl5, Cxcl9 and Cxcl13 continued to increase following CCI. The expression of Ccl2, Ccl3, Ccl4, Ccl6, and Ccl7 were initially upregulated after CCI and subsequently decreased after 12 hours. Similarly, the expression of Rac2, Cd68, Icam-1, Ptprc, Itgb2, and Fcgr2b increased after 12 hours but reduced after 1 day. However, the expression of the above genes increased again 7 days after CCI, when the neuropathic pain affection had developed. Furthermore, gene ontology analysis, Kyoto Encyclopedia of Genes and Genomes pathway enrichment and interaction network analyses further showed a high connectivity degree among these chemokine targeting genes. Similar expressional changes in these genes were found in the rat spinal dorsal horn responsible for nociception processing. Taken together, our results indicated chemokines and their targeting genes in the ACC may be differentially involved in the initiation and maintenance of neuropathic pain affection. These genes may be a target for not only the nociception but also the pain affection following nerve injury.

MiR-15p-5p Mediates the Coordination of ICAM-1 and FAK to Promote Endothelial Cell Proliferation and Migration

Intercellular adhesion molecule-1 (ICAM-1) in endothelial cells is critical for neutrophil adhesion and transmigration across the endothelium. Focal adhesion kinase (FAK), which controls the turnover of focal adhesion to regulate cell adhesion and migration, plays a role in the resolution of inflammation. However, the coordinated involvement of ICAM-1 and FAK during endothelial inflammation has yet to be elucidated. This study reports that, as part of an inflammatory response, ICAM-1 controls FAK expression in endothelial cells via the microRNA miR-15b-5p. Induction of lung injury by lipopolysaccharide (LPS) resulted in higher levels of FAK expression in inflammatory tissues, while in ICAM-1 knockout mice, FAK expression was reduced in the lungs. FAK expression was also reduced in endothelial cells following ICAM-1 siRNA downregulation. Furthermore, ICAM-1 inhibited miR-15b-5p expression while increasing FAK mRNA and protein expression via binding of miR-15b-5p to the 3' untranslated region (UTR) of FAK. ICAM-1 inhibited miR-15b-5p promoter activity and hence reduced miR-15b-5p expression. FAK increased endothelial cell proliferation and migration, whereas miR-15b-5p inhibited cell proliferation and migration. These findings indicate that the inflammatory molecule ICAM-1 regulates FAK expression via miR-15b-5p levels, which in turn controls endothelial cell proliferation and migration.

The Role of miRNA in Regulating the Fate of Monocytes in Health and Cancer

Monocytes represent a heterogeneous population of blood cells that provide a link between innate and adaptive immunity. The unique potential of monocytes as both precursors (e.g., of macrophages) and effector cells (as phagocytes or cytotoxic cells) makes them an interesting research and therapeutic target. At the site of a tumor, monocytes/macrophages constitute a major population of infiltrating leukocytes and, depending on the type of tumor, may play a dual role as either a bad or good indicator for cancer recovery. The functional activity of monocytes and macrophages derived from them is tightly regulated at the transcriptional and post-transcriptional level. This review summarizes the current understanding of the role of small regulatory miRNA in monocyte formation, maturation and function in health and cancer development. Additionally, signatures of miRNA-based monocyte subsets and the influence of exogenous miRNA generated in the tumor environment on the function of monocytes are discussed.

Plasma-derived exosomes implement miR-126-associated regulation of cytokines secretion in PBMCs of CHF patients in vitro

Background The investigation of regulatory effects of intra-exosomal compounds, especially microRNAs, has promising therapeutic prospects in the treatment of numerous diseases, including cardiovascular disorders. In this study, we investigated the effect of healthy donors` plasma exosomes (HDPE) on the production of cytokines by PBMC cells of patients with congestive heart failure (CHF) and showed the integral role of miRNA-126 in CHF-mediated changes of mononuclear paracrine secretion. Methods Peripheral blood mononuclear cells (PBMСs) were isolated from a peripheral blood of fifteen patients with CHF (age, 66,8±9,8 years; left ventricular ejection fraction, 44±19%). The concentration of cytokines (IL-10, ICAM-1, VEGF-A, TNF-α and MCP-1) in culture medium and PBMCs was measured by ELISA. The level of miRNA-126 expression in PBMCs was performed by real-time PCR. Results Dramatic increase of ICAM-1 level in activated PBMCs of CHF patients, as well as an increase of the IL-10, ICAM-1 and TNF-α levels in the culture medium was observed. It was accompanied by CHF-related miRNA-126 overexpression in PBMCs. HDPE treatment distinguished by a tendency to reduction in miRNA-126 expression by CHF PBMCs and correlated with upregulation of IL-10, ICAM-1, TNF-α and MCP-1 with normalization of cytokines secretion. Conclusions The altered paracrine secretion of cytokines by CHF PBMCs and miRNA-126 overexpression in vitro was found. HDPE treatment modulated production and secretion of most of studied cytokines by CHF PBMCs in vitro. The experimental application of exosomes for the modulation of paracrine secretion and PBMCs cellular functions may be promising for CVD therapy, including endothelial dysfunction and CHF.

Sirtuin 6 regulates macrophage polarization to alleviate sepsis-induced acute respiratory distress syndrome via dual mechanisms dependent on and independent of autophagy

BACKGROUND AIMS

Sepsis-induced acute respiratory distress syndrome (ARDS) can be mediated by an imbalance in macrophage polarization; however, the underlying mechanisms remain poorly understood. This study aimed to investigate the modulatory role of sirtuin 6 (SIRT6) in macrophage polarization during sepsis-induced ARDS.

METHODS

A mouse ARDS model was established using cecal ligation and puncture. Isolated alveolar macrophages (AMs) and lipopolysaccharide (LPS)-stimulated bone marrow-derived macrophages (BMDMs) were adopted as in vitro models. Macrophage polarization was evaluated by measuring M1 and M2 macrophage percentages via flow cytometry and expression of specific markers. The expression of microtubule-associated light chain protein 3I/II and beclin-1 was detected for assessing macrophage autophagy. Binding between specificity protein 1 (SP1) and the target gene promoter was evaluated using a chromatin immunoprecipitation assay. RNA expression was analyzed by quantitative reverse transcription polymerase chain reaction and western blotting.

RESULTS

Treatment with the SIRT6 activator UBCS039 significantly alleviated lung injury in the mouse ARDS model and enhanced autophagy and M2 polarization in isolated AMs. M2 polarization and autophagy in LPS-challenged BMDMs were also effectively promoted by UBCS039 treatment or SIRT6 overexpression. An adenosine monophosphate-activated protein kinase inhibitor (Compound C) or autophagy inhibitor (3-methyladenine) partially abrogated M2 polarization mediated by SIRT6 overexpression upon LPS exposure. SIRT6 induced autophagy and M2 polarization of BMDMs partially via its deacetylase activity. SIRT6 inhibited mammalian target of rapamycin transcription by modulating SP1 to promote BMDM M2 polarization, which was independent of autophagy.

CONCLUSIONS

SIRT6 promotes M2 polarization of macrophages to alleviate sepsis-induced ARDS in an autophagy-dependent and -independent manner.

Gene regulation of intracellular adhesion molecule-1 (ICAM-1): A molecule with multiple functions

Intracellular adhesion molecule 1 (ICAM-1) is one of the most extensively studied inducible cell adhesion molecules which is responsible for several immune functions like T cell activation, extravasation, inflammation, etc. The molecule is constitutively expressed over the cell surface and is regulated up / down in response to inflammatory mediators like cellular stress, proinflammatory cytokines, viral infection. These stimuli modulate the expression of ICAM-1 primarily through regulating the ICAM-1 gene transcription. On account of the presence of various binding sites for NF-κB, AP-1, SP-1, and many other transcription factors, the architecture of the ICAM-1 promoter become complex. Transcription factors in union with other transcription factors, coactivators, and suppressors promote their assembly in a stereospecific manner on ICAM-1 promoter which mediates ICAM-1 regulation in response to different stimuli. Along with transcriptional regulation, epigenetic modifications also play a pivotal role in controlling ICAM-1 expression on different cell types. In this review, we summarize the regulation of ICAM-1 expression both at the transcriptional as well as post-transcriptional level with an emphasis on transcription factors and signaling pathways involved.

Targeting Tumor-Associated Macrophages in Cancer Immunotherapy

Tumor-associated macrophages (TAMs) represent the most abundant leukocyte population in most solid tumors and are greatly influenced by the tumor microenvironment. More importantly, these macrophages can promote tumor growth and metastasis through interactions with other cell populations within the tumor milieu and have been associated with poor outcomes in multiple tumors. In this review, we examine how the tumor microenvironment facilitates the polarization of TAMs. Additionally, we evaluate the mechanisms by which TAMs promote tumor angiogenesis, induce tumor invasion and metastasis, enhance chemotherapeutic resistance, and foster immune evasion. Lastly, we focus on therapeutic strategies that target TAMs in the treatments of cancer, including reducing monocyte recruitment, depleting or reprogramming TAMs, and targeting inhibitory molecules to increase TAM-mediated phagocytosis.

Targeting Tumor-Associated Macrophages in Cancer Immunotherapy

Tumor-associated macrophages (TAMs) represent the most abundant leukocyte population in most solid tumors and are greatly influenced by the tumor microenvironment. More importantly, these macrophages can promote tumor growth and metastasis through interactions with other cell populations within the tumor milieu and have been associated with poor outcomes in multiple tumors. In this review, we examine how the tumor microenvironment facilitates the polarization of TAMs. Additionally, we evaluate the mechanisms by which TAMs promote tumor angiogenesis, induce tumor invasion and metastasis, enhance chemotherapeutic resistance, and foster immune evasion. Lastly, we focus on therapeutic strategies that target TAMs in the treatments of cancer, including reducing monocyte recruitment, depleting or reprogramming TAMs, and targeting inhibitory molecules to increase TAM-mediated phagocytosis.

Transforming Growth Factor-β1 Promotes M1 Alveolar Macrophage Polarization in Acute Lung Injury by Up-Regulating DNMT1 to Mediate the microRNA-124/PELI1/IRF5 Axis

Objective

Macrophages function as key orchestrators in the pathogenesis of acute lung injury (ALI). The current study sets out to investigate the molecular mechanism of transforming growth factor-β (TGFβ1) in the regulation of M1 alveolar macrophage polarization in ALI by modulating DNA methyltransferase 1 (DNMT1), along with the microRNA (miR)-124/Pellino 1 (PELI1)/interferon regulatory factor 5 (IRF5) axis.

Methods

First, ALI mouse models were established, and the proportion of M1 and M2 macrophages in mouse lung tissues was detected using flow cytometry. The targeting relationship between miR-124 and PELI1 was verified with the help of a dual luciferase gene reporter assay. Following TGFβ1 knockdown, RT-qPCR and Western blot assay were performed to analyze the expression patterns of TGFβ1, DNMT1, miR-124, and PELI1 and M1/M2 polarization markers in the lung tissues of ALI mice. Immunofluorescence was further employed to detect nuclear translocation of IRF5 in macrophages.

Results

The polarization of M1 macrophages was found to be positively correlated with the severity of lung injury. TGFβ1, DNMT1, PELI1 were highly expressed, while miR-124 was down-regulated in ALI mice, and IRF5 was primarily distributed in the nucleus. TGFβ1 promoted the polarization of M1 alveolar macrophages by up-regulating DNMT1. Furthermore, DNMT1 down-regulated the expression of miR-124, which led to enhancement of M1 alveolar macrophage polarization. Meanwhile, over-expression of miR-124 inhibited the nuclear translocation of IRF5 and suppressed M1 alveolar macrophage polarization. On the other hand, over-expression of PELI1 reversed the above trends.

Conclusion

Collectively, our findings indicated that TGFβ1 can promote the expression of DNMT1, which down-regulates miR-124 to activate PELI1 and nuclear translocation of IRF5, thereby aggravating ALI in mice.

The impact of non-coding RNAs on macrophage polarization

Macrophage polarization is a process through which macrophages attain unique functional features as a response to certain stimuli from their niche. Lipopolysaccharide and Th1 cytokines induce generation of M1 macrophages. On the other hand, IL-4, IL-13, IL-10, IL-33, and TGF-β induce polarization of macrophages towards M2 phenotype. This process is also modulated by a number of miRNAs and lncRNAs. miR-375, miR-let7, miR-34a, miR-155, miR-124, miR-34a, miR-511-3p, miR-99a, miR-132 and miR-145-3p are among miRNAs that regulate macrophage polarization. Meanwhile, macrophage polarization is influenced by some lncRNAs such as H19, NRON, MEG3, GAS5, RN7SK, and AK085865. Macrophage polarization has functional significance in a wide range of human disorders particularly immune disorders and cancer. In addition, the effect of certain drugs in modulation of macrophage polarization is exerted through modulation of expression of non-coding RNAs. In the current manuscript, we provide a summary of studies aimed to identification of this aspect of non-coding RNAs.

Macrophage-derived IL-6 trans-signaling as a novel target in the pathogenesis of bronchopulmonary dysplasia

Rationale

Premature infants exposed to oxygen are at risk for bronchopulmonary dysplasia (BPD), which is characterised by lung growth arrest. Inflammation is important, but the mechanisms remain elusive. Here, we investigated inflammatory pathways and therapeutic targets in severe clinical and experimental BPD.

Methods and results

First, transcriptomic analysis with in silico cellular deconvolution identified a lung-intrinsic M1-like-driven cytokine pattern in newborn mice after hyperoxia. These findings were confirmed by gene expression of macrophage-regulating chemokines (Ccl2, Ccl7, Cxcl5) and markers (Il6, Il17A, Mmp12). Secondly, hyperoxia-activated interleukin 6 (IL-6)/signal transducer and activator of transcription 3 (STAT3) signalling was measured in vivo and related to loss of alveolar epithelial type II cells (ATII) as well as increased mesenchymal marker. Il6 null mice exhibited preserved ATII survival, reduced myofibroblasts and improved elastic fibre assembly, thus enabling lung growth and protecting lung function. Pharmacological inhibition of global IL-6 signalling and IL-6 trans-signalling promoted alveolarisation and ATII survival after hyperoxia. Third, hyperoxia triggered M1-like polarisation, possibly via Krüppel-like factor 4; hyperoxia-conditioned medium of macrophages and IL-6-impaired ATII proliferation. Finally, clinical data demonstrated elevated macrophage-related plasma cytokines as potential biomarkers that identify infants receiving oxygen at increased risk of developing BPD. Moreover, macrophage-derived IL6 and active STAT3 were related to loss of epithelial cells in BPD lungs.

Conclusion

We present a novel IL-6-mediated mechanism by which hyperoxia activates macrophages in immature lungs, impairs ATII homeostasis and disrupts elastic fibre formation, thereby inhibiting lung growth. The data provide evidence that IL-6 trans-signalling could offer an innovative pharmacological target to enable lung growth in severe neonatal chronic lung disease.

M1-like macrophage activation is linked to IL-6/STAT3 axis in clinical and experimental BPD. Inhibition of macrophage-related IL-6 trans-signalling promotes ATII survival and lung growth in experimental BPD as a new therapy for preterm infants.https://bit.ly/3AhF7GP

Zinc Finger Protein St18 Protects against Septic Death by Inhibiting VEGF-A from Macrophages

Zinc finger protein St18 was initially reported as candidate tumor suppressor gene, and also suggested that fibroblast St18 positively regulates NF-κB activation. Despite the pleiotropic functions of St18, little is known about its roles in macrophages. Here, we report that myeloid St18 is a potent inhibitor of VEGF-A. Mice lacking St18 in myeloid lineages exhibit increased retinal vasculature with enhanced serum VEGF-A concentrations. Despite the normal activation of NF-κB target genes, these mice are highly susceptible to LPS-induced shock, polymicrobial sepsis, and experimental colitis, accompanied by enhanced vascular and intestinal leakage. Pharmacological inhibition of VEGF signaling rescued the high mortality rate of myeloid-specific St18-deficient mice in response to inflammation. Mechanistically, St18 directly binds to Sp1 and attenuates its activity, leading to the suppression of Sp1 target gene VEGF-A. Using mouse genetic and pharmacological models, we reveal myeloid St18 as a critical septic death protector.

Common Variants Associated With OSMR Expression Contribute to Carotid Plaque Vulnerability, but Not to Cardiovascular Disease in Humans

Background and Aims: Oncostatin M (OSM) signaling is implicated in atherosclerosis, however the mechanism remains unclear. We investigated the impact of common genetic variants in OSM and its receptors, OSMR and LIFR, on overall plaque vulnerability, plaque phenotype, intraplaque OSMR and LIFR expression, coronary artery calcification burden and cardiovascular disease susceptibility. Methods and Results: We queried Genotype-Tissue Expression data and found that rs13168867 (C allele) was associated with decreased OSMR expression and that rs10491509 (A allele) was associated with increased LIFR expression in arterial tissues. No variant was significantly associated with OSM expression. We associated these two variants with plaque characteristics from 1,443 genotyped carotid endarterectomy patients in the Athero-Express Biobank Study. After correction for multiple testing, rs13168867 was significantly associated with an increased overall plaque vulnerability (β = 0.118 ± s.e. = 0.040, p = 3.00 × 10-3, C allele). Looking at individual plaque characteristics, rs13168867 showed strongest associations with intraplaque fat (β = 0.248 ± s.e. = 0.088, p = 4.66 × 10-3, C allele) and collagen content (β = -0.259 ± s.e. = 0.095, p = 6.22 × 10-3, C allele), but these associations were not significant after correction for multiple testing. rs13168867 was not associated with intraplaque OSMR expression. Neither was intraplaque OSMR expression associated with plaque vulnerability and no known OSMR eQTLs were associated with coronary artery calcification burden, or cardiovascular disease susceptibility. No associations were found for rs10491509 in the LIFR locus. Conclusions: Our study suggests that rs1316887 in the OSMR locus is associated with increased plaque vulnerability, but not with coronary calcification or cardiovascular disease risk. It remains unclear through which precise biological mechanisms OSM signaling exerts its effects on plaque morphology. However, the OSM-OSMR/LIFR pathway is unlikely to be causally involved in lifetime cardiovascular disease susceptibility.

Blocking SNHG14 Antagonizes Lipopolysaccharides-Induced Acute Lung Injury via SNHG14/miR-124-3p Axis

BACKGROUND

Emerging evidence show that long noncoding RNAs (lncRNAs) are crucial regulators in pathophysiology of acute lung injury (ALI). Small nucleolar RNA host gene 14 (SNHG14) is a novel oncogenic lncRNA, and has been associated with inflammation-related cell injuries. Thus, we wondered the role and mechanism of SNHG14 in lipopolysaccharides (LPS)-induced ALI cell model.

METHODS

Expression of SNHG14, miRNA (miR)-124-3p, and transforming growth factor β type 2 receptor (TGFBR2) was detected by RT-qPCR and western blotting. Cell apoptosis was determined by methyl thiazolyl tetrazolium assay, flow cytometry, western blotting, and lactate dehydrogenase activity kit. Inflammation was measured by enzyme-linked immunosorbent assay. The interaction among SNHG14, miR-124-3p, and TGFBR2 was validated by dual-luciferase reporter assay and RNA immunoprecipitation.

RESULTS

LPS administration attenuated human lung epithelial cell viability and B-cell lymphoma-2 expression, but augmented apoptosis rate, cleaved-caspase-3 expression, lactate dehydrogenase activity, and secretions of tumor necrosis factor-α, interleukin-1β, and IL-6 in A549 cells. Thus, LPS induced A549 cells apoptosis and inflammation, wherein SNHG14 was upregulated and miR-124-3p was downregulated. However, silencing SNHG14 could suppress LPS-induced apoptosis and inflammation depending on upregulating miR-124-3p via target binding. Similarly, overexpressing miR-124-3p attenuated LPS-induced A549 cells injury through inhibiting its downstream target TGFBR2. Furthermore, SNHG14 knockdown could also affect TGFBR2 expression via miR-124-3p.

CONCLUSIONS

SNHG14 knockdown prevents A549 cells from LPS-induced apoptosis and inflammation through regulating miR-124-3p and TGFBR2, suggesting a novel SNHG14/miR-124-3p/TGFBR2 circuit in alveolar epithelial cells on the set of ALI.

In vivo effects of olive oil and trans-fatty acids on miR-134, miR-132, miR-124-1, miR-9-3 and mTORC1 gene expression in a DMBA-treated mouse model

Both the intake of beneficial olive oil and of harmful trans-fatty acids (TFAs) in consumed foods are of great significance in tumor biology. In our present study we examined the effects they exert on the expression patterns of miR-134, miR-132, miR-124-1, miR-9-3 and mTOR in the liver, spleen and kidney of mice treated with 7,12-dimethylbenz [a] anthracene (DMBA). Feeding of TFA-containing diet significantly increased the expression of all studied miRs and mTORC1 in all organs examined, except the expression of mTORC1 in the spleen and kidney. Diet containing olive oil significantly reduced the expression of miR-124-1, miR-9-3 and mTORC1 in the liver and spleen. In the kidney, apart from the mTORC1 gene, the expression of all miRs examined significantly decreased compared to the DMBA control. According to our results, the cell membrane protective, antioxidant, and anti-inflammatory effects of olive oil and the cell membrane damaging, inflammatory, and carcinogenic properties of TFA suggest negative feedback regulatory mechanisms. In contrast to our expectations, mTORC1 gene expression in the kidney has not been shown to be an appropriate biomarker-presumably, because the many complex effects that regulate mTOR expression may quench each other.

Screening and identification of key regulatory connections and immune cell infiltration characteristics for lung transplant rejection using mucosal biopsies

This study aimed to explore key regulatory connections underlying lung transplant rejection. The differentially expressed genes (DEGs) between rejection and stable lung transplantation (LTx) samples were screened using R package limma, followed by functional enrichment analysis and protein-protein interaction network construction. Subsequently, a global triple network, including miRNAs, mRNAs, and transcription factors (TFs), was constructed. Furthermore, immune cell infiltration characteristics were analyzed to investigate the molecular immunology of lung transplant rejection. Finally, potential drug-target interactions were generated. In brief, 739 DEGs were found between rejection and stable LTx samples. PTPRC, IL-6, ITGAM, CD86, TLR8, TYROBP, CXCL10, ITGB2, and CCR5 were defined as hub genes. Eight TFs, including STAT1, SPIB, NFKB1, SPI1, STAT5A, RUNX1, VENTX, and BATF, and five miRNAs, including miR-335-5p, miR-26b-5p, miR-124-3p, miR-1-3p, and miR-155-5p, were involved in regulating hub genes. The immune cell infiltration analysis revealed higher proportions of activated memory CD4 T cells, follicular helper T cells, γδ T cells, monocytes, M1 and M2 macrophages, and eosinophils in rejection samples, besides lower proportions of resting memory CD4 T cells, regulatory T cells, activated NK cells, M0 macrophages, and resting mast cells. This study provided a comprehensive perspective of the molecular co-regulatory network underlying lung transplant rejection.

Forsythoside A inhibits adhesion and migration of monocytes to type II alveolar epithelial cells in lipopolysaccharide-induced acute lung injury through upregulating miR-124

Acute lung injury (ALI) is a severe disease for which effective drugs are still lacking at present. Forsythia suspensa is a traditional Chinese medicine commonly used to relieve respiratory symptoms in China, but its functional mechanisms remain unclear. Therefore, forsythoside A (FA), the active constituent of F. suspensa, was studied in the present study. Inflammation models of type II alveolar epithelial MLE-12 cells and BALB/c mice stimulated by lipopolysaccharide (LPS) were established to explore the effects of FA on ALI and the underlying mechanisms. We found that FA inhibited the production of monocyte chemoattractant protein-1 (MCP-1/CCL2) in LPS-stimulated MLE-12 cells in a dose-dependent manner. Moreover, FA decreased the adhesion and migration of monocytes to MLE-12 cells. Furthermore, miR-124 expression was upregulated after FA treatment. The luciferase report assay showed that miR-124 mimic reduced the activity of CCL2 in MLE-12 cells. However, the inhibitory effects of FA on CCL2 expression and monocyte adhesion and migration to MLE-12 cells were counteracted by treatment with a miR-124 inhibitor. Critically, FA ameliorated LPS-induced pathological damage, decreased the serum levels of tumor necrosis factor-α and interleukin-6, and inhibited CCL2 secretion and macrophage infiltration in lungs in ALI mice. Meanwhile, administration of miR-124 inhibitor attenuated the protective effects of FA. The present study suggests that FA attenuates LPS-induced adhesion and migration of monocytes to type II alveolar epithelial cells though upregulating miR-124, thereby inhibiting the expression of CCL2. These findings indicate that the potential application of FA is promising and that miR-124 mimics could also be used in the treatment of ALI.

Dynamics of cytokines, immune cell counts and disease severity in patients with community-acquired pneumonia - Unravelling potential causal relationships

BACKGROUND

Community acquired pneumonia (CAP) is a severe and often rapidly deteriorating disease. To better understand its dynamics and potential causal relationships, we analyzed time series data of cytokines, blood and clinical parameters in hospitalized CAP patients.

METHODS

Time series data of 10 circulating cytokines, blood counts and clinical parameters were related to baseline characteristics of 403 CAP patients using univariate mixed models. Bivariate mixed models were applied to analyze correlations between the time series. To identify potential causal relationships, we inferred cross-lagged relationships between pairs of parameters using latent curve models with structured residuals.

RESULTS

IL-6 levels decreased faster over time in younger patients (P_adj = 0.06). IL-8, VCAM-1, and IL-6 correlated strongly with disease severity as assessed by the sequential organ failure assessment (SOFA) score (r = 0.49, 0.48, 0.46, respectively; all P_adj < 0.001). IL-6 and bilirubin correlated with respect to their mean levels and slopes over time (r = 0.36 and r = 0.46, respectively; P_adj < 0.001). A number of potential causal relationships were identified, e.g., a negative effect of ICAM-1 on MCP-1, or a positive effect of the level of creatinine on the subsequent VCAM-1 concentration (P < 0.001).

CONCLUSIONS

These results suggest that IL-6 trajectories of CAP patients are associated with age and run parallel to bilirubin levels. The time series analysis also unraveled directed, potentially causal relationships between cytokines, blood parameters and clinical outcomes. This will facilitate the development of mechanistic models of CAP, and with it, improvements in treatment or surveillance strategies for this disease.

TRIAL REGISTRATION

clinicaltrials.gov NCT02782013, May 25, 2016, retrospectively registered.

Collagen Density Modulates the Immunosuppressive Functions of Macrophages

Tumor-associated macrophages (TAMs) support tumor growth by suppressing the activity of tumor-infiltrating T cells. Consistently, TAMs are considered a major limitation for the efficacy of cancer immunotherapy. However, the molecular reason behind the acquisition of an immunosuppressive TAM phenotype is not fully clarified. During tumor growth, the extracellular matrix (ECM) is degraded and substituted with a tumor-specific collagen-rich ECM. The collagen density of this tumor ECM has been associated with poor patient prognosis but the reason for this is not well understood. In this study, we investigated whether the collagen density could modulate the immunosuppressive activity of TAMs. The murine macrophage cell line RAW 264.7 was three-dimensionally cultured in collagen matrices of low and high collagen densities mimicking healthy and tumor tissue, respectively. Collagen density did not affect proliferation or viability of the macrophages. However, whole-transcriptome analysis revealed a striking response to the surrounding collagen density, including the regulation of immune regulatory genes and genes encoding chemokines. These transcriptional changes were shown to be similar in murine bone marrow-derived macrophages and TAMs isolated from murine tumors. Strikingly, coculture assays with primary T cells showed that macrophages cultured in high-density collagen were less efficient at attracting cytotoxic T cells and capable of inhibiting T cell proliferation more than macrophages cultured in low-density collagen. Our study demonstrates that a high collagen density can instruct macrophages to acquire an immunosuppressive phenotype. This mechanism could reduce the efficacy of immunotherapy and explain the link between high collagen density and poor prognosis.

Bone marrow fat: friend or foe in people with diabetes mellitus?

Global trends in the prevalence of overweight and obesity put the adipocyte in the focus of huge medical interest. This review highlights a new topic in adipose tissue biology, namely the emerging pathogenic role of fat accumulation in bone marrow (BM). Specifically, we summarize current knowledge about the origin and function of BM adipose tissue (BMAT), provide evidence for the association of excess BMAT with diabetes and related cardiovascular complications, and discuss potential therapeutic approaches to correct BMAT dysfunction. There is still a significant uncertainty about the origins and function of BMAT, although several subpopulations of stromal cells have been suggested to have an adipogenic propensity. BM adipocytes are higly plastic and have a distinctive capacity to secrete adipokines that exert local and endocrine functions. BM adiposity is abundant in elderly people and has therefore been interpreted as a component of the whole-body ageing process. BM senescence and BMAT accumulation has been also reported in patients and animal models with Type 2 diabetes, being more pronounced in those with ischaemic complications. Understanding the mechanisms responsible for excess and altered function of BMAT could lead to new treatments able to preserve whole-body homeostasis.

Targeting Dysfunctional Vascular Endothelial Cells Using Immunoliposomes Under Flow Conditions

Introduction

Atherosclerosis (ATH), the build up of fat in the arteries, is a principal cause of heart attack and stroke. Drug instability and lack of target specificity are major drawbacks of current clinical therapeutics. These undesirable effects can be eliminated by site-specific drug delivery. The endothelial surface over ATH lesions has been shown to overexpress vascular cell adhesion molecule1 (VCAM1), which can be used for targeted therapy.

Methods

Here, we report the synthesis, characterization, and development of anti VCAM1-functionalized liposomes to target cells overexpressing VCAM1 under static and flow conditions. Liposomes were composed of dioleoyl-phosphatidylcholine, sphingomyelin, cholesterol, and distearoyl-phosphatidylethanolamine-polyethylene glycol-cyanur (31.67:31.67:31.67:5 mol%). VCAM1 expression in endothelial cells was induced by lipopolysaccharide (LPS) treatment.

Results

Characterization study revealed that liposomes were negatively charged (- 7.7 ± 2.6 mV) with an average diameter of 201.3 ± 3.3 nm. Liposomes showed no toxicity toward THP-1 derived macrophages and endothelial cells. Liposomes were able to target both fixed and non-fixed endothelial cells, in vitro, with significantly higher localization observed in non-fixed conditions. To mimic biological and physiologically-relevant conditions, liposome targeting was also examined under flow (4 dyn/cm²) with or without erythrocytes (40% v/v hematocrit). Liposomes were able to target LPS-treated endothelial cells under dynamic culture, in the presence or absence of erythrocytes, although targeting efficiency was five-fold lower in flow compared to static conditions.

Conclusions

This liposomal delivery system showed a significant improvement in localization on dysfunctional endothelium after surface functionalization. We conclude that VCAM1-functionalized liposomes can target and potentially deliver therapeutic compounds to ATH regions.

Intercellular Adhesion Molecule 1 Functions as an Efferocytosis Receptor in Inflammatory Macrophages

Intercellular adhesion molecule-1 (ICAM-1) is up-regulated during inflammation by several cell types. ICAM-1 is best known for its role in mediating leukocyte adhesion to endothelial cells and guiding leukocytes across the vascular wall. Recently, macrophages have been shown to express ICAM-1, however, their role in macrophage function is unclear. We found that ICAM-1 expression was induced during inflammatory macrophage polarization and high numbers of ICAM-1-expressing macrophages were noted in inflamed colon tissue in a murine colitis model and in human inflammatory bowel disease. Because tissue macrophages play a critical role in removing apoptotic/necrotic cells in inflammation and injury, a process termed efferocytosis, it was examined whether ICAM-1 contributes to this process. Genetic deletion (ICAM-1 knockout mice) or siRNA-mediated knockdown of ICAM-1 in isolated murine and human macrophages significantly impaired apoptotic cell (AC) engulfment. Impairment in the engulfment of Jurkat T cells, neutrophils, and epithelial cells was confirmed ex vivo by inflammatory macrophages and in vivo by thioglycolate-recruited peritoneal macrophages. Decreased efferocytosis was also seen in vitro and in vivo with inhibition of ICAM-1 adhesive interactions, using a function blocking anti-ICAM-1 antibody. Mechanistically, it was found that ICAM-1 actively redistributes to cluster around engulfed ACs to facilitate macrophage-AC binding. Our findings define a new role for ICAM-1 in promoting macrophage efferocytosis, a critical process in the resolution of inflammation and restoration of tissue homeostasis.

ICAM-1: A master regulator of cellular responses in inflammation, injury resolution, and tumorigenesis

ICAM-1 is a cell surface glycoprotein and an adhesion receptor that is best known for regulating leukocyte recruitment from circulation to sites of inflammation. However, in addition to vascular endothelial cells, ICAM-1 expression is also robustly induced on epithelial and immune cells in response to inflammatory stimulation. Importantly, ICAM-1 serves as a biosensor to transduce outside-in-signaling via association of its cytoplasmic domain with the actin cytoskeleton following ligand engagement of the extracellular domain. Thus, ICAM-1 has emerged as a master regulator of many essential cellular functions both at the onset and at the resolution of pathologic conditions. Because the role of ICAM-1 in driving inflammatory responses is well recognized, this review will mainly focus on newly emerging roles of ICAM-1 in epithelial injury-resolution responses, as well as immune cell effector function in inflammation and tumorigenesis. ICAM-1 has been of clinical and therapeutic interest for some time now; however, several attempts at inhibiting its function to improve injury resolution have failed. Perhaps, better understanding of its beneficial roles in resolution of inflammation or its emerging function in tumorigenesis will spark new interest in revisiting the clinical value of ICAM-1 as a potential therapeutic target.

Butyrate Decreases ICAM-1 Expression in Human Oral Squamous Cell Carcinoma Cells

Short-chain fatty acids (SCFA) are bacterial metabolites that can be found in periodontal pockets. The expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) within the epithelium pocket is considered to be a key event for the selective transmigration of leucocytes towards the gingival sulcus. However, the impact of SCFA on ICAM-1 expression by oral epithelial cells remains unclear. We therefore exposed the oral squamous carcinoma cell line HSC-2, primary oral epithelial cells and human gingival fibroblasts to SCFA, namely acetate, propionate and butyrate, and stimulated with known inducers of ICAM-1 such as interleukin-1-beta (IL1β) and tumor necrosis factor-alfa (TNFα). We report here that butyrate but not acetate or propionate significantly suppressed the cytokine-induced ICAM-1 expression in HSC-2 epithelial cells and primary epithelial cells. The G-protein coupled receptor-43 (GPR43/ FFAR2) agonist but not the histone deacetylase inhibitor, trichostatin A, mimicked the butyrate effects. Butyrate also attenuated the nuclear translocation of p65 into the nucleus on HSC-2 cells. The decrease of ICAM-1 was independent of Nrf2/HO-1 signaling and phosphorylation of JNK and p38. Nevertheless, butyrate could not reverse an ongoing cytokine-induced ICAM-1 expression in HSC-2 cells. Overall, these observations suggest that butyrate can attenuate cytokine-induced ICAM-1 expression in cells with epithelial origin.