miR-181a Induces Macrophage Polarized to M2 Phenotype and Promotes M2 Macrophage-mediated Tumor Cell Metastasis by Targeting KLF6 and C/EBPα

Investigation of the Protective Effect of Extracellular Vesicle miR-124 on Retinal Ganglion Cells Using a Photolabile Paper-Based Chip

Purpose

Photolabile paper-based chips were developed to isolate extracellular vesicles (EVs) from small-volume samples (less than 30 µL), such as vitreous humor. Putative neuroprotective effects of EVs' microRNAs were investigated by using the paper chip and a rodent model with nonarteritic anterior ischemic optic neuropathy (rNAION).

Methods

rNAION was established using laser-induced photoactivation of rose bengal administered intravenously. On days 0, 0.25, 1, 3, and 7 after rNAION induction, CD63-positive EV microRNAs (CD63+-EV miRNAs) in vitreous humor samples were enriched using the paper chip and assessed using microarray and quantitative RT-PCR analyses. The viability and visual function of retinal ganglion cells (RGCs) were further assessed by measuring photopic flash visual evoked potentials (FVEPs).

Results

We identified 38 different variations of CD63+-EV miRNAs with more than twofold altered expressions. Among them, M1-related miRNA, mR-31a-5p, and M2-related miRNA, miR-125a-5p, miR-182, miR-181a-5p, and miR-124-3, were capable of coordinating anti-inflammatory reactions during rNAION because of their capacity to activate macrophages. In particular, miR-124, having the most dramatic alteration of gene expression, was synthesized and injected intravitreally. Compared to controls, rats that received miR-124 had shown increased RGC survivability and improved visual function.

Conclusions

Our research team has developed a paper-based chip capable of capturing EVs that can be released after UV exposure. The quantity and quality of EV-miRNAs extracted are adequate for microarray and quantitative RT-PCR analyses. Animal studies suggest that miR-124 may play a neuroprotective role in the natural recovery of rNAION and holds the potential to be a novel treatment option.

MYC-mediated silencing of miR-181a-5p promotes pathogenic Th17 responses by modulating AKT3-FOXO3 signaling

Pathogenic Th17 cells drive autoimmune pathology, but the molecular mechanisms underlying Th17 pathogenicity remain poorly understood. Here, we have shown that miR-181a-5p was significantly decreased in pathogenic Th17 cells, and it negatively regulated pathogenic Th17 cell responses in vitro and in vivo. Th17 cells overexpressing miR-181a-5p exhibited impaired ability to induce pathogenesis in an adoptive transfer model of experimental autoimmune uveitis (EAU). Mechanistically, miR-181a-5p directly targeted AKT3, diminishing AKT3-mediated phosphorylation of FOXO3, and thereby activating FOXO3, a transcriptional repressor of pathogenic Th17 cell program. Supporting this, decreasing miR-181a-5p and up-regulated AKT3 expression were found in uveitis patients. Furthermore, intravitreal administration of miR-181a-5p mimics in mice effectively attenuated clinical and pathological signs of established EAU. Collectively, our results reveal a previously unappreciated T cell-intrinsic role of miR-181a-5p in restraining autoimmunity and may provide a potential therapeutic target for uveitis treatment.

Downregulation of krüppel-like factor 6 expression modulates extravillous trophoblast cell behavior by increasing reactive oxygen species

INTRODUCTION

Placental extravillous trophoblasts play a crucial role in the establishment of a healthy pregnancy. Reactive oxygen species (ROS) may contribute to their differentiation and function as mediators in signaling processes or might cause oxidative stress resulting in trophoblast dysfunction. The krüppel-like transcription factor 6 (KLF6) regulates many genes involved in essential cell processes where ROS are also involved. However, whether KLF6 regulates ROS levels has not been previously investigated.

MATERIALS AND METHODS

KLF6 was silenced by siRNAs in HTR8-SV/neo cells, an extravillous trophoblast model. Total and mitochondrial ROS levels, as well as mitochondrial membrane potential and apoptosis were analyzed by flow cytometry. The expression of genes and proteins of interest were analyzed by qRT-PCR and Western blot, respectively. Cell response to oxidative stress, proliferation, viability, morphology, and migration were evaluated.

RESULTS

KLF6 downregulation led to an increase in ROS and NOX4 mRNA levels, accompanied by reduced cell proliferation and increased p21 protein expression. Catalase activity, 2-Cys peroxiredoxin protein levels, Nrf2 cytoplasmic localization and hemoxygenase 1 expression, as well as mitochondrial membrane potential and cell apoptosis were not altered suggesting that ROS increase is not associated with cellular damage. Instead, KLF6 silencing induced cytoskeleton modifications and increased cell migration in a ROS-dependent manner.

DISCUSSION

Present data reveal a novel role of KLF6 on ROS balance and signaling demonstrating that KLF6 downregulation induces an increase in ROS levels that contribute to extravillous trophoblast cell migration.

Stem Cells in the Tumor Immune Microenvironment -Part of the Cure or Part of the Disease? Ontogeny and Dichotomy of Stem and Immune Cells has Led to better Understanding

Stem cells are at the basis of tissue homeostasis, hematopoiesis and various regenerative processes. Epigenetic changes in their somatically imprinted genes, prolonged exposure to mutagens/carcinogens or alteration of their niche can lead to the development of an enabling environment for tumor growth and progression. The involvement of stem cells in both health and disease becomes even more compelling with ontogeny as embryonic and extraembryonic stem cells which persist into adulthood in well established and specific niche may have distinct implications in tumorigenesis. Immune surveillance plays an important role in this interplay since the response of immune cells toward the oncogenic process can range from reactivity to placidity and even complicity, being orchestrated by intercellular molecular dialogues with the other key players of the tumor microenvironment. With the current understanding that every developing and adult tissue contains inherent stem and progenitor cells, in this manuscript we review the most relevant interactions carried out between the stem cells, tumor cells and immune cells in a bottom-up incursion through the tumor microenvironment beginning from the perivascular niche and going through the tumoral parenchyma and the related stroma. With the exploitation of various factors that influence the behavior of immune effectors toward stem cells and other resting cells in their niche, new therapeutic strategies to tackle the polarization of immune effectors toward a more immunogenic phenotype may arise.

The Pathogenicity and Virulence of Leishmania - interplay of virulence factors with host defenses

Leishmaniasis is a group of disease caused by the intracellular protozoan parasite of the genus Leishmania. Infection by different species of Leishmania results in various host immune responses, which usually lead to parasite clearance and may also contribute to pathogenesis and, hence, increasing the complexity of the disease. Interestingly, the parasite tends to reside within the unfriendly environment of the macrophages and has evolved various survival strategies to evade or modulate host immune defense. This can be attributed to the array of virulence factors of the vicious parasite, which target important host functioning and machineries. This review encompasses a holistic overview of leishmanial virulence factors, their role in assisting parasite-mediated evasion of host defense weaponries, and modulating epigenetic landscapes of host immune regulatory genes. Furthermore, the review also discusses the diagnostic potential of various leishmanial virulence factors and the advent of immunomodulators as futuristic antileishmanial drug therapy.

MicroRNAs as Regulators of Phagocytosis

MicroRNAs (miRNAs) are short non-coding RNAs that regulate gene expression and thus act as important regulators of cellular phenotype and function. As their expression may be dysregulated in numerous diseases, they are of interest as biomarkers. What is more, attempts of modulation of some microRNAs for therapeutic reasons have been undertaken. In this review, we discuss the current knowledge regarding the influence of microRNAs on phagocytosis, which may be exerted on different levels, such as through macrophages polarization, phagosome maturation, reactive oxygen species production and cytokines synthesis. This phenomenon plays an important role in numerous pathological conditions.

Characterization of Microfragmented Adipose Tissue Architecture, Mesenchymal Stromal Cell Content and Release of Paracrine Mediators

The use of microfragmented adipose tissue (µFAT) for the treatment of musculoskeletal disorders, especially osteoarthritis (OA), is gaining popularity, following positive results reported in recent case series and clinical trials. Although these outcomes were postulated to rely on paracrine signals, to date, a thorough fingerprint of released molecules is largely missing. The purpose of this study was to first characterize both structure and cell content of unprocessed lipoaspirate (LA) and µFAT, and further identify and frame the array of signaling factors in the context of OA disease, by means of high throughput qRT-PCR for extracellular-vesicle (EV) embedded miRNAs and proteomics for tissue and secreted factors. Cell count showed reduction of blood cells in µFAT, confirmed by histological and flow cytometry analyses, that also showed a conserved presence of structural, endothelial and stromal components and pericytes. In the secretome, 376 and 381 EV-miRNAs in LA and µFAT, respectively, were identified. In particular, most abundant and µFAT upregulated EV-miRNAs were mainly recapitulating those already reported as ASC-EVs-specific, with crucial roles in cartilage protection and M2 macrophage polarization, while only a scarce presence of those related to blood cells emerged. Furthermore, secretome proteomic analysis revealed reduction in µFAT of acute phase factors driving OA progression. Taken together, these results suggest that processing of LA into µFAT allows for removal of blood elements and maintenance of tissue structure and stromal cell populations, and possibly the increase of OA-protective molecular features. Thus, microfragmentation represents a safe and efficient method for the application of adipose tissue properties in the frame of musculoskeletal disorders.

Non-Coding RNAs in the Crosstalk between Breast Cancer Cells and Tumor-Associated Macrophages

Non-coding RNAs (ncRNAs) play a pivotal role in regulating the tumor microenvironment (TME) by controlling gene expression at multiple levels. In tumors, ncRNAs can mediate the crosstalk between cancer cells and other cells in the TME, such as immune cells, stromal cells, and endothelial cells, influencing tumor development and progression. Tumor-associated macrophages (TAMs) are among the most abundant inflammatory cells infiltrating solid cancers that promote tumorigenesis, and their infiltration correlates with a poor prognosis in many tumors. Cancer cells produce different ncRNAs that orchestrate TAM recruitment and polarization toward a tumor-promoting phenotype. Tumor-reprogrammed macrophages shape the TME by promoting angiogenesis and tissue remodeling, and suppressing the anti-tumor activity of adaptive immune cells. TAMs can also produce ncRNA molecules that boost cancer cell proliferation and direct their phenotype and metabolic changes facilitating cancer progression and metastasis. This review will focus on the crosstalk between cancer cells and TAMs mediated by microRNAs and long non-coding RNAs during breast cancer (BC) initiation and progression.

Apoptotic bodies extracted from adipose mesenchymal stem cells carry microRNA-21-5p to induce M2 polarization of macrophages and augment skin wound healing by targeting KLF6

BACKGROUND

Adipose-derived mesenchymal stem cells (adMSCs) are suggested as potential tools for the treatment of regenerative diseases, including tissue repair. This study aimed to explore the function of adMSC-derived apoptotic bodies in skin wound healing and the molecules of action.

METHODS

The acquired adMSCs and their-derived apoptotic bodies were identified. A murine model of full-thickness skin wounds was treated with apoptotic bodies. The wound healing process of mice and the pathological changes in wound tissues were examined. Ana-1 macrophages were treated with lipopolysaccharide (LPS) and apoptotic bodies for in vitro experiments. Polarization of macrophages was examined by immunofluorescence staining of the specific biomarkers and ELISA kits. Dermal microvascular endothelial cells (DMECs) or dermal fibroblasts (DFs) were co-cultured with apoptotic bodies or the LPS- and apoptotic bodies-treated Ana-1 cells. Downstream molecules mediated by apoptotic bodies were screened by microarray and bioinformatic analyses.

RESULTS

Apoptotic bodies treatment accelerated skin wound healing in mice and promoted formation of granulation tissues and blood vessels in wound tissues. Apoptotic bodies treatment induced M2 polarization of macrophages. The angiogenesis ability of DMECs, and the viability and migration of DFs were increased when co-cultured with the apoptotic bodies-treated Ana-1 cells. MicroRNA (miR)-21-5p was abundantly expressed in ABs, and kruppel like factor 6 (KLF6) mRNA was confirmed as a target of miR-21-5p. Overexpression of KLF6 reduced M2 polarization of macrophages and blocked the promoting effect of apoptotic bodies on wound healing in vitro and in vivo.

CONCLUSION

miR-21-5p carried by adMSC-derived apoptotic bodies targets KLF6 to induce M2 polarization of macrophages and augment skin wound healing.

The Extensive Regulation of MicroRNA in Immune Thrombocytopenia

MicroRNA (miRNA) is a small, single-stranded, non-coding RNA molecule that plays a variety of key roles in different biological processes through post-transcriptional regulation of gene expression. MiRNA has been proved to be a variety of cellular processes involved in development, differentiation, signal transduction, and is an important regulator of immune and autoimmune diseases. Therefore, it may act as potent modulators of the immune system and play an important role in the development of several autoimmune diseases. Immune thrombocytopenia (ITP) is an autoimmune systemic disease characterized by a low platelet count. Several studies suggest that like other autoimmune disorders, miRNAs are deeply involved in the pathogenesis of ITP, interacting with the function of innate and adaptive immune responses. In this review, we discuss emerging knowledge about the function of miRNAs in ITP and describe miRNAs in terms of their role in the immune system and autoimmune response. These findings suggest that miRNA may be a useful therapeutic target for ITP by regulating the immune system. In the future, we need to have a more comprehensive understanding of miRNAs and how they regulate the immune system of patients with ITP.

miRNAs in the Regulation of Cancer Immune Response: Effect of miRNAs on Cancer Immunotherapy

In the last few decades, carcinogenesis has been extensively explored and substantial research has identified immunogenic involvement in various types of cancers. As a result, immune checkpoint blockers and other immune-based therapies were developed as novel immunotherapeutic strategies. However, despite being a promising therapeutic option, immunotherapy has significant constraints such as a high cost of treatment, unpredictable toxicity, and clinical outcomes. miRNAs are non-coding, small RNAs actively involved in modulating the immune system's multiple signalling pathways by binding to the 3'-UTR of target genes. miRNAs possess a unique advantage in modulating multiple targets of either the same or different signalling pathways. Therefore, miRNA follows a 'one drug multiple target' hypothesis. Attempts are made to explore the therapeutic promise of miRNAs in cancer so that it can be transported from bench to bedside for successful immunotherapeutic results. Therefore, in the current manuscript, we discussed, in detail, the mechanism and role of miRNAs in different types of cancers relating to the immune system, its diagnostic and therapeutic aspect, the effect on immune escape, immune-checkpoint molecules, and the tumour microenvironment. We have also discussed the existing limitations, clinical success and the prospective use of miRNAs in cancer.

Nanoparticle-Mediated Targeted Drug Delivery to Remodel Tumor Microenvironment for Cancer Therapy

Advanced research has revealed the crucial role of tumor microenvironment (TME) in tumorigenesis. TME consists of a complicated network with a variety of cell types including endothelial cells, pericytes, immune cells, cancer-associated fibroblasts (CAFs), cancer stem cells (CSCs) as well as the extracellular matrix (ECM). The TME-constituting cells interact with the cancerous cells through plenty of signaling mechanisms and pathways in a dynamical way, participating in tumor initiation, progression, metastasis, and response to therapies. Hence, TME is becoming an attractive therapeutic target in cancer treatment, exhibiting potential research interest and clinical benefits. Presently, the novel nanotechnology applied in TME regulation has made huge progress. The nanoparticles (NPs) can be designed as demand to precisely target TME components and to inhibit tumor progression through TME modulation. Moreover, nanotechnology-mediated drug delivery possesses many advantages including prolonged circulation time, enhanced bioavailability and decreased toxicity over traditional therapeutic modality. In this review, update information on TME remodeling through NPs-based targeted drug delivery strategies for anticancer therapy is summarized.

Mesenchymal stem cell-derived exosomal miR-21a-5p promotes M2 macrophage polarization and reduces macrophage infiltration to attenuate atherosclerosis

Atherosclerosis (AS) is the main pathological basis for ischemic cardiovascular and cerebrovascular diseases. Mesenchymal stem cell (MSC)-derived exosomes have the potential to alleviate AS, while the underlying mechanism remains unclear. Here, we aimed to investigate the mechanism of MSC-derived exosomes in AS. The AS mouse model was prepared by feeding ApoE-/- mice with high-fat diet. AS mice were administered with MSC-derived exosomes, and the atherosclerotic plaque area was analyzed by Oil Red O staining. Mouse RAW264.7 macrophages were incubated with MSC-derived exosomes. The macrophage infiltration, macrophage proportion, and cell migration were estimated by immunohistochemistry, flow cytometry, or Transwell assay. The relationship between miR-21a-5p and kruppel-like factor 6 (KLF6) or extracellular signal-regulated protein kinases 2 (ERK2) was verified by luciferase reporter assay. We found that MSC-derived exosomes promoted M2 polarization of macrophages and reduced plaque area and macrophage infiltration in AS mice. miR-21a-5p overexpression caused an increase of M2 macrophages in RAW264.7 cells and led to a decrease in migration of RAW264.7 cells. Moreover, both KLF6 and ERK2 are the targets of miR-21a-5p. MSC-derived exosomes containing miR-21a-5p promoted M2 polarization of RAW264.7 cells by suppressing KLF6 expression. MSC-derived exosomes containing miR-21a-5p inhibited migration of RAW264.7 cells through inhibiting the ERK1/2 signaling pathway. In conclusion, MSC-derived exosomes containing miR-21a-5p promote macrophage polarization and reduce macrophage infiltration by targeting KLF6 and ERK1/2 signaling pathways, thereby attenuating the development of AS. Thus, MSC-derived exosomes may be a promising treatment for AS.

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.

Tumor-Associated Macrophages as Multifaceted Regulators of Breast Tumor Growth

Breast cancer is the most commonly occurring cancer in women of Western countries and is the leading cause of cancer-related mortality. The breast tumor microenvironment contains immune cells, fibroblasts, adipocytes, mesenchymal stem cells, and extracellular matrix. Among these cells, macrophages or tumor-associated macrophages (TAMs) are the major components of the breast cancer microenvironment. TAMs facilitate metastasis of the breast tumor and are responsible for poor clinical outcomes. High TAM density was also found liable for the poor prognosis of breast cancer. These observations make altering TAM function a potential therapeutic target to treat breast cancer. The present review summarizes the origin of TAMs, mechanisms of macrophage recruitment and polarization in the tumor, and the contributions of TAMs in tumor progression. We have also discussed our current knowledge about TAM-targeted therapies and the roles of miRNAs and exosomes in re-educating TAM function.

MiR-200b is upregulated in plasma-derived exosomes and functions as an oncogene by promoting macrophage M2 polarization in ovarian cancer

Background

Ovarian cancer is the seventh most common cancer in women and the second most reason of gynecologic cancer-related death. Growing evidence showed that exosomal miRNA plays a crucial role in the progression of ovarian cancer.

Methods

Exosomes were identified using nanoparticle tracking analysis, transmission electron microscopy and marker proteins detection. The levels of mRNA and proteins were ensured by qRT-PCR and western blot, respectively. Immunofluorescence, flow cytometry and ELISA assay were carried out to analyze macrophages polarization. CCK-8 and Transwell assay were used to measure the cell viability and invasion of ovarian cancer cells. The interaction of miR-200b and Kruppel like factor 6 (KLF6) was ensured by using luciferase reporter assay.

Results

Here, we obtained plasma-derived exosomes successfully, and proved that miR-200b was increased in the exosomes of ovarian cancer patients. Subsequently, our data showed that increasing of miR-200b could promote macrophage M2 polarization, but inhibit M1 polarization. miR-200b-overexpressed macrophages-conditioned medium notably enhanced the cell viability and invasion of ovarian cancer cells. Moreover, increasing of miR-200b inhibited KLF6 expression, while decreasing of miR-200b promoted KLF6 expression. Overexpression of KLF6 recused miR-200b-induced macrophage polarization toward M2, and the inhibitory effect of miR-200b on M1 polarization.

Conclusions

Overall, our results demonstrated that miR-200b was highly expressed in the plasma-derived exosome of ovarian cancer patients, and promoted the proliferation and invasion of ovarian cancer cells through inducing macrophage M2 polarization by suppressing KLF6 expression. Our results suggested that miR-200b might be a novel target for ovarian cancer treatment.

MiR-451a enhances the phagocytosis and affects both M1 and M2 polarization in macrophages

Leukemia associated macrophages (LAMs), which are different from tumor-associated macrophages as well as classical M1 and M2 macrophages, are specifically activated by leukemic microenvironment. We have reported the heterogeneity of gene expression profiles in LAMs. However, the expression profiles of microRNA (miRNA) in LAMs and their regulatory mechanisms have not been established. Here, the expression profiles of miRNA in LAMs from bone marrow and spleen of acute myeloid leukemia mice were analyzed. Then, the effects of miR-451a, which was upregulated in LAMs, on macrophages were studied by transfecting miRNA mimic to peritoneal macrophages. The results showed that overexpression of miR-451a altered the morphology, enhanced the phagocytic ability of macrophages, and promotes the expression of differentiation marker CD11b in macrophages. Furthermore, miR-451a increased the proliferation capacity of both M1- and M2-polarized macrophages, but not M0 macrophages. Moreover, miR-451a further enhanced the expression of iNOS upon M1 activation. Therefore, our results reveal the miRNA expression profiles in LAMs, and broaden the knowledge about miRNA regulation in macrophages.

MiR-19a-3p Suppresses M1 Macrophage Polarization by Inhibiting STAT1/IRF1 Pathway

Macrophages, an important type of immune cells, are generally polarized to classically activated macrophage (M1) or alternatively activated macrophage (M2) to respond to environmental stimuli. Signal transducer and activator of transcription 1 (STAT1), a very important transcription factor, can promote M1 macrophage polarization. However, the mechanisms of regulating STAT1 in macrophage polarization remain unclear. In the present study, STAT1 was markedly elevated, however, miR-19a-3p was down-regulated in interferon (IFN)-γ and lipopolysaccharide (LPS) treated RAW264.7 cells, and dual-luciferase reporter assay identified that miR-19a-3p directly targeted STAT1 by binding to its 3′UTR. Up-regulated miR-19a-3p inhibited M1 polarization by targeting STAT1/interferon regulatory factor 1 (IRF1) and vice versa in vitro. Consistently, overexpression of miR-19a-3p in LPS treated mice by systemically administering agomiR-19a-3p effectively reduced the inflammation in mouse lung tissues, and inhibited M1 macrophage polarization via suppressing STAT1/IRF1 pathway. In summary, our study confirmed that miR-19a-3p, as a direct regulator of STAT1, inhibited M1 macrophages polarization. The miR-19a-3p/STAT1/IRF1 pathway can potentially be used to design novel immunotherapy for modulating macrophage polarization.

A narrative review of tumor-associated macrophages in lung cancer: regulation of macrophage polarization and therapeutic implications

Lung cancer is the deadliest malignancy worldwide. An inflammatory microenvironment is a key factor contributing to lung tumor progression. Tumor-Associated Macrophages (TAMs) are prominent components of the cancer immune microenvironment with diverse supportive and inhibitory effects on growth, progression, and metastasis of lung tumors. Two main macrophage phenotypes with different functions have been identified. They include inflammatory or classically activated (M1) and anti-inflammatory or alternatively activated (M2) macrophages. The contrasting functions of TAMs in relation to lung neoplasm progression stem from the presence of TAMs with varying tumor-promoting or anti-tumor activities. This wide spectrum of functions is governed by a network of cytokines and chemokines, cell-cell interactions, and signaling pathways. TAMs are promising therapeutic targets for non-small cell lung cancer (NSCLC) treatment. There are several strategies for TAM targeting and utilizing them for therapeutic purposes including limiting monocyte recruitment and localization through various pathways such as CCL2-CCR2, CSF1-CSF1R, and CXCL12-CXCR4, targeting the activation of TAMs, genetic and epigenetic reprogramming of TAMs to antitumor phenotype, and utilizing TAMs as the carrier for anti-cancer drugs. In this review, we will outline the role of macrophages in the lung cancer initiation and progression, pathways regulating their function in lung cancer microenvironment as well as the role of these immune cells in the development of future therapeutic strategies.

Vascular Macrophages as Therapeutic Targets to Treat Intracranial Aneurysms

Aneurysmal subarachnoid hemorrhage (aSAH) is a highly fatal and morbid type of hemorrhagic strokes. Intracranial aneurysms (ICAs) rupture cause subarachnoid hemorrhage. ICAs formation, growth and rupture involves cellular and molecular inflammation. Macrophages orchestrate inflammation in the wall of ICAs. Macrophages generally polarize either into classical inflammatory (M1) or alternatively-activated anti-inflammatory (M2)-phenotype. Macrophage infiltration and polarization toward M1-phenotype increases the risk of aneurysm rupture. Strategies that deplete, inhibit infiltration, ameliorate macrophage inflammation or polarize to M2-type protect against ICAs rupture. However, clinical translational data is still lacking. This review summarizes the contribution of macrophage led inflammation in the aneurysm wall and discuss pharmacological strategies to modulate the macrophageal response during ICAs formation and rupture.

Super enhancer-mediated transcription of miR146a-5p drives M2 polarization during Leishmania donovani infection

The outcome of Leishmania donovani infection depends upon the dynamic interchanges between M1 and M2 macrophages. Information of the involvement of microRNAs (miRNAs) and epigenetic modifiers in regulating macrophage plasticity during L. donovani infection is still elusive. Differential expression analysis of polarization-regulating miRNAs, revealed significant enrichment of miR146a-5p during Leishmania donovani infection. A sustained enrichment of miR146a-5p was observed in both infected bone marrow derived macrophages (BMDMs) and BALB/c mice organs. We found involvement of miR146a-5p in phagocytosis and survivability of parasites. Moreover, miR146a-5pgot enriched in interleukin 4- stimulated BMDMs, indicating its possible involvement in M2 polarization. Upon transfecting BMDMs with miRVANA anti-146a oligos, M2 markers (CCR7, YM-1, FIZZ-1, arginase-1, IL10 and IL4) and transcription factors (p-STAT6 and c/EBPβ) got depleted with concomitant augmentation of M1-polarizing transcription factors (p-STAT1, AP1 and IRF-1), miR146a target genes (TRAF6 and IRAK1), M1 cytokines (IL12 and TNFα), iNOS, nitric oxide, and nuclear translocation of phospho p-65 subunit. Neutralization of intracellular mature miR146a-5p pool in infected BALB/c mice lower organ parasite burden and expressions of M2 markers and IL10 with enrichment of M1 markers like iNOS and IL12. Additionally, we explored the novel role of super enhancer (SE), a cis-acting regulatory component, to enrich miR146a-5p expression during infection. Enhanced expression and nuclear retention of SE components like BET bromodomain 4 (BRD4) and p300 were found in infected BMDMs. Upon silencing BRD4, expressions of miR146a-5p and M2 markers were down regulated and TRAF6, IRAK1 and iNOS levels increased. STRING V.11 based predication and immune precipitation confirmed the strong interaction amongst BRD4, p300 and RNA pol II (RpbI). Chromatin immune precipitation studies suggested the recruitment of BRD4 at the enhancer loci of miR146a-5p gene during infection. Altogether, our findings revealed a novel role of BRD4/p300-depdendent super-enhancer in regulating miR146a expression during L. donovani infection which in turn mediates M2 polarization and immune-suppression.

Visceral leishmaniasis (VL), caused by protozoan parasites Leishmania donovani, is the most severe form of leishmaniasis and is highly lethal if left untreated. Major obstacle for successful therapy of VL originates from the life-long immune-suppression triggered in the post kala-azar dermal leishmaniasis (PKDL) patients during infection. Identification of molecular principles behind such immune-suppression will add success in VL therapeutics. L. donovani hijacks the host macrophages and converts them from pro-inflammatory M1 to immune-suppressive M2 type, which allows successful infection establishment. Herein, we explored the indispensable role of miRNA-146a-5p in conversion of M1 to M2 type during infection. Both in vitro and in vivo miRNA silencing established miR146a-5p as an imperative negative regulator ofM1 polarization. Computational analysis as well as immune precipitation based experiments authenticated that L. donovani induces super enhancer complex mediated transcriptional upregulation of miR146a-5p. BET bromodomain protein 4 (BRD4) forms this SE complex along with p300 histone acetyl transferase and RNA pol II. Silencing of BRD4 significantly abrogated miR146a-5p mediated M2 polarization. In short, our current findings established a previously unrecognized role of BRD4-depdendent super enhancers in orchestrating persistent transcription of macrophage miR146a-5p which in turn promotes M2 polarization during L. donovani infection.

Trdmt1 3'-untranslated region functions as a competing endogenous RNA in leukemia HL-60 cell differentiation

Severe blockage in myeloid differentiation is the hallmark of acute myeloid leukemia (AML). Trdmt1 plays an important role in hematopoiesis. However, little is known about the function of Trdmt1 in AML cell differentiation. In the present study, Trdmt1 was up-regulated and miR-181a was down-regulated significantly during human leukemia HL-60 cell differentiation after TAT-CT3 fusion protein treatment. Accordingly, miR-181a overexpression in HL-60 cells inhibited granulocytic maturation. In addition, our "rescue" assay demonstrated that Trdmt1 3'-untranslated region promoted myeloid differentiation of HL-60 cells by sequestering miR-181a and up-regulating C/EBPα (a critical factor for normal myelopoiesis) via its competing endogenous RNA (ceRNA) activity on miR-181a. These findings revealed an unrecognized role of Trdmt1 as a potential ceRNA for therapeutic targets in AML.

Serum and Glucocorticoid-Inducible Kinase 1 (SGK1) in NSCLC Therapy

Non-small cell lung cancer (NSCLC) remains the most prevalent and one of the deadliest cancers worldwide. Despite recent success, there is still an urgent need for new therapeutic strategies. It is also becoming increasingly evident that combinatorial approaches are more effective than single modality treatments. This review proposes that the serum and glucocorticoid-inducible kinase 1 (SGK1) may represent an attractive target for therapy of NSCLC. Although ubiquitously expressed, SGK1 deletion in mice causes only mild defects of ion physiology. The frequent overexpression of SGK1 in tumors is likely stress-induced and provides a therapeutic window to spare normal tissues. SGK1 appears to promote oncogenic signaling aimed at preserving the survival and fitness of cancer cells. Most importantly, recent investigations have revealed the ability of SGK1 to skew immune-cell differentiation toward pro-tumorigenic phenotypes. Future studies are needed to fully evaluate the potential of SGK1 as a therapeutic target in combinatorial treatments of NSCLC. However, based on what is currently known, SGK1 inactivation can result in anti-oncogenic effects both on tumor cells and on the immune microenvironment. A first generation of small molecules to inactivate SGK1 has already been already produced.

microRNA-18a from M2 Macrophages Inhibits TGFBR3 to Promote Nasopharyngeal Carcinoma Progression and Tumor Growth via TGF-β Signaling Pathway

OBJECTIVES

Nasopharyngeal carcinoma (NPC) is a type of nasopharyngeal disease with high metastasis and invasion properties. Tumor-associated alternative activated (M2) macrophages are evidenced to connect with NPC. Based on this, this study purposes to explore the mechanism and participation of microRNA-18a (miR-18a) from M2 macrophages in NPC.

METHODS

Peripheral blood mononuclear cells were differentiated to macrophages and macrophages were polarized to M2 type by interleukin-4. SUNE-1 and CNE2 cells were transfected with restored or depleted miR-18a or transforming growth factor-beta III receptor (TGFBR3) to explore their roles in NPC progression with the involvement of the TGF-β signaling pathway. Next, SUNE-1 and CNE2 cells were co-cultured with M2 macrophages that had been treated with restored or depleted miR-18a or TGFBR3 to comprehend their combined roles in NPC with the involvement of the TGF-β signaling pathway.

RESULTS

MiR-18a was highly expressed and TGFBR3 was lowly expressed in NPC cells. MiR-18a restoration, TGFBR3 knockdown or co-culture with miR-18a mimics, or si-TGFBR3-transfected M2 macrophages promoted SUNE-1 cell progression, tumor growth in mice, decreased p-Smad1/t-Smad1, and elevated p-Smad3/t-Smad3. miR-18a downregulation, TGFBR3 overexpression, or co-culture with miR-18a inhibitors or OE-TGFBR3-transfected M2 macrophages depressed CNE2 cell progression, tumor growth in mice, increased p-Smad1/t-Smad1, and decreased p-Smad3/t-Smad3.

CONCLUSION

Our study elucidates that miR-18a from M2 macrophages results in promoted NPC cell progression and tumor growth in nude mice via TGFBR3 repression, along with the Smad1 inactivation and Smad3 activation.

Up-regulation of MiR-145-5p promotes the growth and migration in LPS-treated HUVECs through inducing macrophage polarization to M2

MiR-145-5p is high-expressed in human vascular endothelial cells (HUVECs) and alternatively activated macrophages (M2). However, whether miR-145-5p can reduce HUVEC damage by regulating macrophage immunophenotype is less reported. THP-1 was stimulated by Phorbolate-12-myristate-13-acetate, LPS and IFN-γ, and IL-4 to differentiate into macrophages (M0, M1 and M2). The expressions of macrophage markers were detected by Western blotting, and the expressions of miR-145-5p and kruppel-like factor-14 (KLF14) were detected by qRT-PCR. Dual-luciferase reporter assay was used to analyze the targeted relationship of miR-145-5p and KLF14. HUVEC injury was induced by LPS and then co-cultured with M1 transfected by miR-145-5p mimic. The effect of miR-145-3p on proliferation and metastasis of LPS-induced HUVECs was detected by MTT, clone formation, scratch assay and Transwell. We found that the expression of miR-145-5p was higher in M2 than that in M1. MiR-145-5p expression was down-regulated during M2-to-M1, but up-regulated during M1-to-M2. The expressions of IL-1β and iNOS were down-regulated, while the protein expressions of CCL17 and Arg-1 were up-regulated by miR-145-5p mimic in M0. The viability, proliferation, migration and invasion of HUVECs were promoted, however, LDH activity of the HUVECs was inhibited by mimics. In addition, KLF14 was predicted as the target gene for miR-145-5p in HUVECs. Collectively, our results demonstrate that miR-145-5p inhibited cell proliferation of LPS-treated HUVECs possibly through regulating macrophage polarization to M2.

Two Sides of the Same Coin: The Roles of KLF6 in Physiology and Pathophysiology

The Krüppel-like factors (KLFs) family of proteins control several key biological processes that include proliferation, differentiation, metabolism, apoptosis and inflammation. Dysregulation of KLF functions have been shown to disrupt cellular homeostasis and contribute to disease development. KLF6 is a relevant example; a range of functional and expression assays suggested that the dysregulation of KLF6 contributes to the onset of cancer, inflammation-associated diseases as well as cardiovascular diseases. KLF6 expression is either suppressed or elevated depending on the disease, and this is largely due to alternative splicing events producing KLF6 isoforms with specialised functions. Hence, the aim of this review is to discuss the known aspects of KLF6 biology that covers the gene and protein architecture, gene regulation, post-translational modifications and functions of KLF6 in health and diseases. We put special emphasis on the equivocal roles of its full-length and spliced variants. We also deliberate on the therapeutic strategies of KLF6 and its associated signalling pathways. Finally, we provide compelling basic and clinical questions to enhance the knowledge and research on elucidating the roles of KLF6 in physiological and pathophysiological processes.

Transcriptional, Epigenetic and Metabolic Programming of Tumor-Associated Macrophages

Macrophages are key innate immune cells in the tumor microenvironment (TME) that regulate primary tumor growth, vascularization, metastatic spread and tumor response to various types of therapies. The present review highlights the mechanisms of macrophage programming in tumor microenvironments that act on the transcriptional, epigenetic and metabolic levels. We summarize the latest knowledge on the types of transcriptional factors and epigenetic enzymes that control the direction of macrophage functional polarization and their pro- and anti-tumor activities. We also focus on the major types of metabolic programs of macrophages (glycolysis and fatty acid oxidation), and their interaction with cancer cells and complex TME. We have discussed how the regulation of macrophage polarization on the transcriptional, epigenetic and metabolic levels can be used for the efficient therapeutic manipulation of macrophage functions in cancer.

MiR-103 protects from recurrent spontaneous abortion via inhibiting STAT1 mediated M1 macrophage polarization

Recurrent spontaneous abortion (RSA) is a common complication of early pregnancy. Excessive M1 macrophage was found to be involved in RSA, but the underlying mechanisms remains unclear. MicroRNAs play critical roles in RSA as well as the polarization of macrophages; however, the regulatory effect of miRNAs on M1 differentiation in RSA has not been fully investigated. In this study, miRNA microarray assay revealed that miR-103 was significantly decreased in RAW264.7-derived M1 macrophages upon IFNγ and LPS stimulation. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis showed that in RSA patients, miR-103 expression was decreased substantially, and negatively correlated with that of STAT1. Moreover, down-regulation of miR-103 could sensitively discriminate RSA patients from normal pregnancies (NP) subjects. Experiments in vitro showed that overexpression of miR-103 suppressed M1 polarization by inhibiting STAT1/IRF1 signaling pathway and vice versa. miR-103 regulated STAT1 expression by direct binding to its 3'-UTR. Moreover, our in vivo study demonstrated that overexpressed miR-103 could reduce mice embryo resorption and M1 polarization effectively. Overall, the results suggested that decreased miR-103 was involved in RSA by increasing M1 macrophage polarization via promoting STAT1/IRF1 signaling pathway. miR-103 may be explored as a promising diagnostic marker and therapeutic target for RSA.

LINC00703 Acts as a Tumor Suppressor via Regulating miR-181a/KLF6 Axis in Gastric Cancer

Purpose

Long noncoding RNA 00703 (LINC00703) was found originating from a region downstream of Kruppel-like factor 6 (KLF6) gene, having 2 binding sites for miR-181a. Since KLF6 has been reported as a target of miR-181a in gastric cancer (GC), this study aims to investigate whether LINC00703 regulates the miR-181a/KLF6 axis and plays a functional role in GC pathogenesis.

Materials and Methods

GC tissues, cell lines, and nude mice were included in this study. RNA binding protein immunoprecipitation (RIP) and pull-down assays were used to evaluate interaction between LINC00703 and miR-181a. Quantitative real-time polymerase chain reaction and western blot were applied for analysis of gene expression at the transcriptional and protein levels. A nude xenograft mouse model was used to determine LINC00703 function in vivo.

Results

We revealed that LINC00703 competitively interacts with miR-181a to regulate KLF6. Overexpression of LINC00703 inhibited cell proliferation, migration/invasion, but promoted apoptosis in vitro, and arrested tumor growth in vivo. LINC00703 expression was found to be decreased in GC tissues, which was positively correlated with KLF6, but negatively with the miR-181a levels.

Conclusions

LINC00703 may have an anti-cancer function via modulation of the miR-181a/KLF6 axis. This study also provides a new potential diagnostic marker and therapeutic target for GC treatment.

Altered expression of miR-181 affects cell fate and targets drug resistance-related mechanisms

MicroRNAs (miRNAs) are non-coding transcripts which regulate genetic and epigenetic events by interfering with mRNA translation. miRNAs are involved in regulation of cell fate due to their ability of interfering with physiological or pathological processes. In this review paper, we evaluate the role of miR-181 family members as prognostic or diagnostic markers or therapeutic targets in malignant pathologies in connection with the main hallmarks of cancer that are modulated by the family. Also, we take over the dual role of this family in dependency with the tumour suppressor and oncogenic features presented in cell and cancer type specific manner. Restoration of the altered expression levels contributes to the activation of cell death pathways or to a reduction in the invasion and migration mechanism; moreover, the mechanism of drug resistance is also modulated by miR-181 sequences with important applications in therapeutic strategies for malignant cells sensitisation. Overall, the main miR-181 family regulatory mechanisms are presented in a cancer specific context, emphasizing the possible clinical application of this family in terms of novel diagnosis and therapy approaches.

The Role of miRNAs in Immune Cell Development, Immune Cell Activation, and Tumor Immunity: With a Focus on Macrophages and Natural Killer Cells

The tumor microenvironment (TME) is the primary arena where tumor cells and the host immune system interact. Bidirectional communication between tumor cells and the associated stromal cell types within the TME influences disease initiation and progression, as well as tumor immunity. Macrophages and natural killer (NK) cells are crucial components of the stromal compartment and display either pro- or anti-tumor properties, depending on the expression of key regulators. MicroRNAs (miRNAs) are emerging as such regulators. They affect several immune cell functions closely related to tumor evasion of the immune system. This review discusses the role of miRNAs in the differentiation, maturation, and activation of immune cells as well as tumor immunity, focusing particularly on macrophages and NK cells.

Intrinsic adriamycin resistance in p53-mutated breast cancer is related to the miR-30c/FANCF/REV1-mediated DNA damage response

Adriamycin(ADR) is still considered to be one of the most effective agents in the treatment of breast cancer (BrCa), its efficacy is compromised by intrinsic resistance or acquire characteristics of multidrug resistance. At present, there are few genetic alterations that can be exploited as biomarkers to guide targeted use of ADR in clinical. Therefore, exploring the determinants of ADR sensitivity is pertinent for their optimal clinical application. TP53 is the most frequently mutated gene in human BrCa, p53 mutation has been reported to be closely related to ADR resistance, whereas the underlying mechanisms that cause endogenous ADR resistance in p53-mutant BrCa cells are not completely understood. The aim of the present study was to investigate the potential roles of miRNA in the response to ADR in p53-mutated breast cancer. Here, we report that BrCa cells expressing mutp53 are more resistant to ADR than cells with wild-type p53 (wtp53). The DNA repair protein- Fanconi anemia complementation group F protein (FANCF) and the translesion synthesis DNA polymerase REV1 protein is frequently abundant in the context of mutant p53 of BrCa. By targeting two key factors, miR-30c increases the sensitivity of BrCa cells to ADR. Furthermore, p53 directly activates the transcription of miR-30c by binding to its promoter. Subsequent analyses revealed that p53 regulates REV1 and FANCF by modulating miR-30c expression. Mutation of the p53 abolished this response. Consistently, reduced miR-30c expression is highly correlated with human BrCa with p53 mutational status and is associated with poor survival. We propose that one of the pathways affected by mutant p53 to increase intrinsic resistance to ADR involves miR-30c downregulation and the consequent upregulation of FANCF and REV1. The novel miRNA-mediated pathway that regulates chemoresistance in breast cancer will facilitate the development of novel therapeutic strategies.

Pulmonary fibroblasts-secreted CXCL10 polarizes alveolar macrophages under pro-inflammatory stimuli

BACKGROUND

During acute lung injury, lung fibroblasts produce chemokines that assist the activation and migration of resident macrophages. The interactions between pulmonary fibroblasts and alveolar macrophages demonstrate the early event in the recruitment of immune cells, and the production of chemokines appear to be central mediators of the initiation and progression of inflammatory responses. In this study, the aim was to investigate the signaling pathway leading to CXCL10 secretion and the effects of CXCL10 released by activated fibroblasts on regulating macrophage polarization in a pro-inflammatory microenvironment.

METHODS

The expression of chemokines CCL2, CCL5, CXCL10, and CXCL12, and the phosphorylation of signaling molecules STAT3, FAK, GSK3αβ and PKCδ were investigated by real time-PCR, ELISA, or Western blot on TNFα- or IL-1β-activated MRC-5 pulmonary fibroblasts. By collecting conditioned medium from TNFα-activated fibroblasts, the expression of iNOS and arginase I on MH-S alveolar macrophages were examined by real-time PCR. Surface markers CD86 and CD206 expressions on alveolar macrophages were also evaluated by flow cytometry.

RESULTS

We found that CXCL10 production was significantly elevated on MRC-5 fibroblasts under TNFα- or IL-1β treatment. In addition, we revealed that TNFα and IL-1β initiated phosphorylation of STAT3, FAK, GSK3αβ and PKCδ signaling cascade, leading to the elevation of CXCL10 expression. Moreover, conditioned medium collected from TNFα-activated MRC-5 fibroblasts increased iNOS and CD86 expressions and decreased arginase I and CD206 expressions on MH-S alveolar macrophages, and neutralization of CXCL10 abolished these observed phenomena.

CONCLUSION

These results suggest that CXCL10 is crucial in activated fibroblasts-promoted M1 phenotype polarization of alveolar macrophages. In this regard, targeting fibroblasts-released CXCL10 may be promising as anti-inflammatory therapy against acute lung injury.

Bioinformatics analysis of mRNA and miRNA microarray to identify the key miRNA‑gene pairs in small‑cell lung cancer

Small-cell lung cancer (SCLC) is a type of lung cancer with early metastasis, and high recurrence and mortality rates. The molecular mechanism is still unclear and further research is required. The aim of the present study was to examine the pathogenesis and potential molecular markers of SCLC by comparing the differential expression of mRNA and microRNA (miRNA) between SCLC tissue and normal lung tissue. A transcriptome sequencing dataset (GSE6044) and a non-coding RNA sequence dataset (GSE19945) were downloaded from the Gene Expression Omnibus (GEO) database. In total, 451 differentially expressed genes (DEGs) and 134 differentially expressed miRNAs (DEMs) were identified using the R limma software package and the GEO2R tool of the GEO, respectively. The Gene Ontology function was significantly enriched for 28 terms, and the Kyoto Encyclopedia of Genes and Genomes database had 19 enrichment pathways, mainly related to ‘cell cycle’, ‘DNA replication’ and ‘oocyte meiosis mismatch repair’. The protein-protein interaction network was constructed using Cytoscape software to identify the molecular mechanisms of key signaling pathways and cellular activities in SCLC. The 1,402 miRNA-gene pairs encompassed 602 target genes of the DEMs using miRNAWalk, which is a bioinformatics platform that predicts DEM target genes and miRNA-gene pairs. There were 19 overlapping genes regulated by 32 miRNAs between target genes of the DEMs and DEGs. Bioinformatics analysis may help to better understand the role of DEGs, DEMs and miRNA-gene pairs in cell proliferation and signal transduction. The related hub genes may be used as biomarkers for the diagnosis and prognosis of SCLC, and as potential drug targets.

MicroRNA-32 targeting PTEN enhances M2 macrophage polarization in the glioma microenvironment and further promotes the progression of glioma

This study was aimed to explore the molecular mechanism of macrophage polarization and its effect on glioma progression. THP1 cells were cocultured in conditioned medium from U87 human glioblastoma cells to simulate the glioma microenvironment. The expression of miR-32 and PTEN in THP1 cells was detected by real-time PCR. A luciferase reporter assay was conducted to confirm the target relation between miR-32 and PTEN. Western blot assays and ELISA were performed to detect PTEN, M2 macrophage-specific markers, PI3K/AKT signaling proteins, and apoptosis-related proteins. U87 cell proliferation was evaluated by CCK-8 and colony forming assays, and the migration ability of the cells was evaluated by Transwell and wound healing assays. The U87 culture supernatant promoted the M2 phenotype of THP1 cells. miR-32 was upregulated and PTEN was downregulated in THP1 cells with the M2 phenotype in the glioma microenvironment. Luciferase assays confirmed that PTEN expression was suppressed by miR-32 through interaction with the 3'UTR of PTEN. Overexpression of miR-32 suppressed PTEN expression in THP1 cells. Overexpression of miR-32 or downregulation of PTEN promoted the expression of M2 macrophage-specific markers, thereby enhancing M2 macrophage polarization. Additionally, miR-32 inhibited THP1 cell apoptosis via suppressing the PI3K/AKT signaling pathway. Most importantly, the proliferation and migration capacities of U87 cells treated with the THP1 culture supernatant after miR-32 overexpression were enhanced, and these effects could be reversed by cotransfection with pcDNA3.1-PTEN. miR-32 negatively modulates PTEN, thereby promoting M2 macrophage transformation through PI3K/AKT signaling, enhancing glioma proliferation and migration abilities.

miR-181a/b therapy in lung cancer: reality or myth?

Despite substantial progress in oncology, lung cancer remains the number one malignancy in terms of both incidence and mortality rates, and there thus remains an urgent need for new therapeutic alternatives. MicroRNA (miRNA) have an important role in cancer initiation and progression due to their capacity to interfere with transcriptional signaling and regulate key cellular processes. miR-181a and miR-181b (miR-181a/b), which are located on chromosomes 1 and 9, are pathologically expressed in the tumor tissue and plasma of patients diagnosed with lung cancer. The miR-181a/b regulatory mechanisms are sophisticated and are directly related to different target genes. In recent years, an ever-increasing number of studies have focused on the biological relevance of miR-181a/b in key cellular processes. In this paper, we aim to discuss the challenging experimental data related to miR-181a/b and their potential use for the development of new therapeutic approaches in lung cancer. We will further present the ongoing issues regarding the regulation of their multiple target genes, and their potential use as biomarkers and therapeutic targets in this deadly malignancy.

Circ_0078767 suppresses non-small-cell lung cancer by protecting RASSF1A expression via sponging miR-330-3p

Objectives

This study was designed to investigate the role of circ_0078767/miR‐330‐3p/RASSF1A in non‐small‐cell lung cancer (NSCLC). Bioinformatic analysis was performed to screen for the differentially expressed genes in NSCLC tissues from adjacent lung tissues.

Materials and Methods

qRT‐PCR was used to detect the RNA expression of genes in cells and tissues, and Western blot was conducted to determine the protein levels of RASSF1A in tissues and cells. A miRanda algorithm was used to predict the targeted relationship among RNAs. A dual‐luciferase reporter gene assay was conducted to verify the targeted relationship. Flow cytometry was performed to investigate the effects of circ_0078767/miR‐330‐3p/RASSF1A on cell cycle progression and apoptosis. A CCK‐8 assay was conducted to explore the effects of circ_0078767/miR‐330‐3p/RASSF1A on cell proliferation. A transwell invasion assay was completed to study the effects of circ_0078767/miR‐330‐3p/RASSF1A on cell invasion. Lastly, an in vivo assay was conducted to investigate the effects of circ_0078767/miR‐330‐3p/RASSF1A on tumour development.

Results

Circ_0078767 and RASSF1A were downregulated, while miR‐330‐3p was upregulated in NSCLC tissues than that in adjacent tissues. miR‐330‐3p had a binding relationship with circ_0078767 and RASSF1A. The overexpression of circ_0078767 and RASSF1A or the underexpression of miR‐330‐3p significantly suppressed NSCLC cell viability, cell cycle progression and invasion while also significantly promoting cell apoptosis. Additionally, these modulations significantly suppressed in vivo tumour growth.

Conclusions

Circ_0078767 could suppress NSCLC progression by inhibiting miR‐330‐3p, which thereby increased RASSF1 levels.

How to reprogram microglia toward beneficial functions

Microglia, brain cells of nonneural origin, orchestrate the inflammatory response to diverse insults, including hypoxia/ischemia or maternal/fetal infection in the perinatal brain. Experimental studies have demonstrated the capacity of microglia to recognize pathogens or damaged cells activating a cytotoxic response that can exacerbate brain damage. However, microglia display an enormous plasticity in their responses to injury and may also promote resolution stages of inflammation and tissue regeneration. Despite the critical role of microglia in brain pathologies, the cellular mechanisms that govern the diverse phenotypes of microglia are just beginning to be defined. Here we review emerging strategies to drive microglia toward beneficial functions, selectively reporting the studies which provide insights into molecular mechanisms underlying the phenotypic switch. A variety of approaches have been proposed which rely on microglia treatment with pharmacological agents, cytokines, lipid messengers, or microRNAs, as well on nutritional approaches or therapies with immunomodulatory cells. Analysis of the molecular mechanisms relevant for microglia reprogramming toward pro‐regenerative functions points to a central role of energy metabolism in shaping microglial functions. Manipulation of metabolic pathways may thus provide new therapeutic opportunities to prevent the deleterious effects of inflammatory microglia and to control excessive inflammation in brain disorders.

Chemopreventive Effects of Phytochemicals and Medicines on M1/M2 Polarized Macrophage Role in Inflammation-Related Diseases

Macrophages can polarize into two different states (M1 and M2), which play contrasting roles during pathogenesis or tissue damage. M1 polarized macrophages produce pro-inflammatory cytokines and mediators resulting in inflammation, while M2 macrophages have an anti-inflammatory effect. Secretion of appropriate cytokines and chemokines from macrophages can lead to the modification of the microenvironment for bridging innate and adaptive immune responses. Increasing evidence suggests that polarized macrophages are pivotal for disease progression, and the regulation of macrophage polarization may provide a new approach in therapeutic treatment of inflammation-related diseases, including cancer, obesity and metabolic diseases, fibrosis in organs, brain damage and neuron injuries, and colorectal disease. Polarized macrophages affect the microenvironment by secreting cytokines and chemokines while cytokines or mediators that are produced by resident cells or tissues may also influence macrophages behavior. The interplay of macrophages and other cells can affect disease progression, and therefore, understanding the activation of macrophages and the interaction between polarized macrophages and disease progression is imperative prior to taking therapeutic or preventive actions. Manipulation of macrophages can be an entry point for disease improvement, but the mechanism and potential must be understood. In this review, some advanced studies regarding the role of macrophages in different diseases, potential mechanisms involved, and intervention of drugs or phytochemicals, which are effective on macrophage polarization, will be discussed.

MicroRNA-150 targets PU.1 and regulates macrophage differentiation and function in experimental autoimmune encephalomyelitis

PU.1 is a transcription factor which is expressed in myeloid cells. Herein, we investigated the expression of PU.1 and its potentially targeting miRNAs in the central nervous system (CNS) of mice with experimental autoimmune encephalitis (EAE) and in cultured primary macrophages. PU.1 levels where highly induced in EAE spinal cords and in activated macrophages; this was associated with a significant reduction in miR-150-5p levels at chronic phase of disease and in activated cells. Luciferase assays confirmed the PU.1-miR-150-5p interaction. Overexpression of miR-150-5p in macrophages decreased the expression of proinflammatory cytokines and shifted the polarization of macrophages away from the M1-like phenotype.

Transcriptional Regulation of Macrophages Polarization by MicroRNAs

Diversity and plasticity are the hallmarks of cells from the monocyte-macrophage lineage. Macrophages undergo classical M1 or alternative M2 activation in response to the microenvironment signals. Several transcription factors, such as peroxisome proliferator-activated receptors, signal transducers and activators of transcription, CCAAT-enhancer-binding proteins, interferon regulatory factors, Kruppel-like factors, GATA binding protein 3, nuclear transcription factor-κB, and c-MYC, were found to promote the expression of specific genes, which dictate the functional polarization of macrophages. Importantly, these transcription factors can be regulated by microRNAs (miRNAs), a group of small non-coding RNAs, which regulate gene expression through translation repression or mRNA degradation. Recent studies have also revealed that miRNAs control macrophage polarization by regulating transcription factors in response to the microenvironment signals. This review will summarize recent progress of miRNAs in the transcriptional regulation of macrophage polarization and provide the insights into the development of macrophage-centered diagnostic and therapeutic strategies.

MiRNAs: dynamic regulators of immune cell functions in inflammation and cancer

MicroRNAs (miRNAs), small noncoding RNA molecules, have emerged as important regulators of almost all cellular processes. By binding to specific sequence motifs within the 3'- untranslated region of their target mRNAs, they induce either mRNA degradation or translational repression. In the human immune system, potent miRNAs and miRNA-clusters have been discovered, that exert pivotal roles in the regulation of gene expression. By targeting cellular signaling hubs, these so-called immuno-miRs have fundamental regulative impact on both innate and adaptive immune cells in health and disease. Importantly, they also act as mediators of tumor immune escape. Secreted by cancer cells and consecutively taken up by immune cells, immuno-miRs are capable to influence immune functions towards a blunted anti-tumor response, thus shaping a permissive tumor environment. This review provides an overview of immuno-miRs and their functional impact on individual immune cell entities. Further, implications of immuno-miRs in the amelioration of tumor surveillance are discussed.

miRNA regulation of innate immunity

MicroRNAs (miRNAs) are small noncoding RNA and are pivotal posttranscriptional regulators of both innate and adaptive immunity. They act by regulating the expression of multiple immune genes, thus, are the important elements to the complex immune regulatory network. Deregulated expression of specific miRNAs can lead to potential autoimmunity, immune tolerance, hyper-inflammatory phenotype, and cancer initiation and progression. In this review, we discuss the contributory pathways and mechanisms by which several miRNAs influence the development of innate immunity and fine-tune immune response. Moreover, we discuss the consequence of deregulated miRNAs and their pathogenic implications.

MicroRNA networks associated with active systemic juvenile idiopathic arthritis regulate CD163 expression and anti-inflammatory functions in macrophages through two distinct mechanisms

Systemic juvenile idiopathic arthritis (SJIA) is a severe childhood arthropathy with features of autoinflammation. Monocytes and macrophages in SJIA have a complex phenotype with both pro- and anti-inflammatory properties that combine features of several well characterized in vitro conditions used to activate macrophages. An important anti-inflammatory phenotype is expression of CD163, a scavenger receptor that sequesters toxic pro-inflammatory complexes that is highly expressed in both active SJIA and macrophage activation syndrome (MAS). CD163 is most strongly up-regulated by IL-10 (M(IL-10)), and not by other conditions that reflect features seen in SJIA monocytes such as M(LPS+IC). MicroRNA plays key roles in integrating cellular signals such as those in macrophage polarization, and as such we hypothesize microRNAs regulate macrophage functional responses in SJIA including CD163 expression. We find that 2 microRNAs previously found to be elevated in active SJIA, miR-125a-5p and miR-181c, significantly reduced macrophage CD163 expression through 2 distinct mechanisms. Neither microRNA was elevated in M(IL-10) with robust CD163 expression, but were instead induced in M(LPS+IC) where they restricted CD163 mRNA expression. Mir-181 species directly targeted CD163 mRNA for degradation. In contrast, miR-125a-5p functions indirectly, as transcriptome analysis of miR-125a-5p overexpression identified "cytokine-cytokine receptor interactions" as the most significantly repressed gene pathway, including decreased IL10RA, required for IL-10-mediated CD163 expression. Finally, overexpression of miR-181c inhibited CD163 anti-inflammatory responses to hemoglobin or high mobility group box 1 (HMGB1) complexes. Together, these data show that microRNA utilizes multiple mechanisms to integrate well-characterized polarization phenotypes and regulate macrophage functional properties seen in SJIA.

MicroRNA expression changes in association with changes in interleukin-1ß/interleukin10 ratios produced by monocytes in autism spectrum disorders: their association with neuropsychiatric symptoms and comorbid conditions (observational study)

BACKGROUND

MicroRNAs (miRNAs) play a major role in regulating immune responses at post-transcriptional levels. Previously, we have reported fluctuating interlukine-1ß (IL-1ß)/IL-10 ratios produced by peripheral blood monocytes (PBMo) in some patients with autism spectrum disorders (ASD). This study examined whether changes in miRNA expression by PBMo are associated with changes in IL-1ß/IL-10 ratios and how such changes are associated with ASD clinical features.

METHODS

miRNA expression by purified PBMo from ASD subjects (N = 69) and non-ASD controls (N = 27) were determined by high-throughput sequencing. Cytokine production by PBMo in responses to stimuli of innate immunity, and behavioral symptoms [assessed by aberrant behavioral checklist (ABC)] were also evaluated at the same time of sample obtainment.

RESULTS

As a whole, there was no difference in miRNA expression between ASD and control non-ASD PBMo. However, when ASD cells were subdivided into 3 groups with high, normal, or low IL-1ß/IL-10 ratios as defined in the "Results" section, in comparison with the data obtained from non-ASD controls, we observed marked changes in miRNA expression. Namely, over 3-fold changes in expression of miR-181a, miR-93, miR-223, miR-342, and miR-1248 were observed in ASD PBMo with high or low IL-1ß/IL-10 ratios, but not in ASD PBMo with normal ratios. These miRNAs that had altered in expression are those closely associated with the regulation of key signaling pathways. With changes in IL-1ß/IL-10 ratios, we also observed changes in the production of cytokines (IL-6, TNF-α, and TGF-ß) other than IL-1ß/IL-10 by ASD PBMo. The association between behavioral symptoms and cytokine levels was different when ASD cells exhibit high/low IL-1ß/IL-10 ratios vs. when ASD cells exhibited normal ratios. Non-IgE-mediated food allergy was also observed at higher frequency in ASD subjects with high/low IL-1ß/IL-10 ratios than with normal ratios.

CONCLUSIONS

Changes in cytokine profiles and miRNA expression by PBMo appear to be associated with changes in ASD behavioral symptoms. miRNAs that are altered in expression in ASD PBMo with high/low IL-1ß/IL-10 ratios are those associated with inflammatory responses. Changes in IL-1ß/IL-10 ratios along with changes in miRNA expression may serve as biomarkers for immune-mediated inflammation in ASD.

Cathelicidin-WA polarizes E. coli K88-induced M1 macrophage to M2-like macrophage in RAW264.7 cells

Immune cells - macrophages induced by E. coli K88 will lead to a pro-inflammatory response, which is important in host defense. Cathelicidin-WA (CWA) is an efficient antimicrobial peptide (AMP) and can exert immunomodulatory properties. Many studies have demonstrated that AMP can modulate cellular subsets but whether CWA can regulate macrophage polarization by transferring E. coli K88-induced M1 macrophage towards M2 one that of anti-inflammation remains unclear. In this study, E. coli K88 increased the expression of pro-inflammatory cytokines interleukin-6, interleukin-1β, tumor necrosis factor-α and chemokine CCL3 in RAW264.7 cells with a time-dependent manner, as well as the expression of reactive oxygen species (ROS) and inducible nitric oxide synthase (iNOS). On this basis, CWA significantly decreased the pro-inflammatory molecules but increased the anti-inflammatory mediators interleukin-4, interleukin-10 and other M2-related genes in E. coli K88-induced macrophages. Western blot analysis indicated that CWA suppressed the expression of TLR-4 and the phosphorylation of STAT1 and NF-κB which modulated M1 macrophage while induced the phosphorylation of STAT6 which activated M2 macrophage. Double staining of M1-specific CD86 and M2-specific CD206 also proved the hypothesis. These results suggested that CWA might dampen the inflammation by modulating M1 phenotype to M2 phenotype in E. coli K88-induced macrophages.

Integrin-Mediated Interactions Control Macrophage Polarization in 3D Hydrogels

Adverse immune reactions prevent clinical translation of numerous implantable devices and materials. Although inflammation is an essential part of tissue regeneration, chronic inflammation ultimately leads to implant failure. In particular, macrophage polarity steers the microenvironment toward inflammation or wound healing via the induction of M1 and M2 macrophages, respectively. Here, this paper demonstrates that macrophage polarity within biomaterials can be controlled through integrin-mediated interactions between human monocytic THP-1 cells and collagen-derived matrix. Surface marker, gene expression, biochemical, and cytokine profiling consistently indicate that THP-1 cells within a biomaterial lacking cell attachment motifs yield proinflammatory M1 macrophages, whereas biomaterials with attachment sites in the presence of interleukin-4 (IL-4) induce an anti-inflammatory M2-like phenotype and propagate the effect of IL-4 in induction of M2-like macrophages. Importantly, integrin α2β1 plays a pivotal role as its inhibition blocks the induction of M2 macrophages. The influence of the microenvironment of the biomaterial over macrophage polarity is further confirmed by its ability to modulate the effect of IL-4 and lipopolysaccharide, which are potent inducers of M2 or M1 phenotypes, respectively. Thus, this study represents a novel, versatile, and effective strategy to steer macrophage polarity through integrin-mediated 3D microenvironment for biomaterial-based programming.