Histone demethylase JMJD1C promotes the polarization of M1 macrophages to prevent glioma by upregulating miR-302a

Insights of immune cell heterogeneity, tumor-initiated subtype transformation, drug resistance, treatment and detecting technologies in glioma microenvironment

BACKGROUND

With the gradual understanding of glioma development and the immune microenvironment, many immune cells have been discovered. Despite the growing comprehension of immune cell functions and the clinical application of immunotherapy, the precise roles and characteristics of immune cell subtypes, how glioma induces subtype transformation of immune cells and its impact on glioma progression have yet to be understood.

AIM OF THE REVIEW

In this review, we comprehensively center on the four major immune cells within the glioma microenvironment, particularly neutrophils, macrophages, lymphocytes, myeloid-derived suppressor cells (MDSCs), and other significant immune cells. We discuss (1) immune cell subtype markers, (2) glioma-induced immune cell subtype transformation, (3) the mechanisms of each subtype influencing chemotherapy resistance, (4) therapies targeting immune cells, and (5) immune cell-associated single-cell sequencing. Eventually, we identified the characteristics of immune cell subtypes in glioma, comprehensively summarized the exact mechanism of glioma-induced immune cell subtype transformation, and concluded the progress of single-cell sequencing in exploring immune cell subtypes in glioma.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In conclusion, we have analyzed the mechanism of chemotherapy resistance detailly, and have discovered prospective immunotherapy targets, excavating the potential of novel immunotherapies approach that synergistically combines radiotherapy, chemotherapy, and surgery, thereby paving the way for improved immunotherapeutic strategies against glioma and enhanced patient outcomes.

A comprehensive insight into the contribution of epigenetics in male infertility; focusing on immunological modifications

Numerous recent studies have examined the impact epigenetics-including DNA methylation-has on spermatogenesis and male infertility. Differential methylation of several genes has been linked to compromised spermatogenesis and/or reproductive failure. Specifically, male infertility has been frequently associated with DNA methylation abnormalities of MEST and H19 inside imprinted genes and MTHFR within non-imprinted genes. Microbial infections mainly result in male infertility because of the immune response triggered by the bacteria' accumulation of immune cells, proinflammatory cytokines, and chemokines. Thus, bacterially produced epigenetic dysregulations may impact host cell function, supporting host defense or enabling pathogen persistence. So, it is possible to think of pathogenic bacteria as potential epimutagens that can alter the epigenome. It has been demonstrated that dysregulated levels of LncRNA correlate with motility and sperm count in ejaculated spermatozoa from infertile males. Therefore, a thorough understanding of the relationship between decreased reproductive capacity and sperm DNA methylation status should aid in creating new diagnostic instruments for this condition. To fully understand the mechanisms influencing sperm methylation and how they relate to male infertility, more research is required.

Macrophage plasticity: signaling pathways, tissue repair, and regeneration

Macrophages are versatile immune cells with remarkable plasticity, enabling them to adapt to diverse tissue microenvironments and perform various functions. Traditionally categorized into classically activated (M1) and alternatively activated (M2) phenotypes, recent advances have revealed a spectrum of macrophage activation states that extend beyond this dichotomy. The complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications orchestrates macrophage polarization, allowing them to respond to various stimuli dynamically. Here, we provide a comprehensive overview of the signaling cascades governing macrophage plasticity, focusing on the roles of Toll-like receptors, signal transducer and activator of transcription proteins, nuclear receptors, and microRNAs. We also discuss the emerging concepts of macrophage metabolic reprogramming and trained immunity, contributing to their functional adaptability. Macrophage plasticity plays a pivotal role in tissue repair and regeneration, with macrophages coordinating inflammation, angiogenesis, and matrix remodeling to restore tissue homeostasis. By harnessing the potential of macrophage plasticity, novel therapeutic strategies targeting macrophage polarization could be developed for various diseases, including chronic wounds, fibrotic disorders, and inflammatory conditions. Ultimately, a deeper understanding of the molecular mechanisms underpinning macrophage plasticity will pave the way for innovative regenerative medicine and tissue engineering approaches.

Overview of the interplay between m6A methylation modification and non-coding RNA and their impact on tumor cells

N6-methyladenosine (m6A) is one of the most common internal modifications in eukaryotic RNA. The presence of m6A on transcripts can affect a series of fundamental cellular processes, including mRNA splicing, nuclear transportation, stability, and translation. The m6A modification is introduced by m6A methyltransferases (writers), removed by demethylases (erasers), and recognized by m6A-binding proteins (readers). Current research has demonstrated that m6A methylation is involved in the regulation of malignant phenotypes in tumors by controlling the expression of cancer-related genes. Non-coding RNAs (ncRNAs) are a diverse group of RNA molecules that do not encode proteins and are widely present in the human genome. This group includes microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and PIWI interaction RNAs (piRNAs). They function as oncogenes or tumor suppressors through various mechanisms, regulating the initiation and progression of cancer. Previous studies on m6A primarily focused on coding RNAs, but recent discoveries have revealed the significant regulatory role of m6A in ncRNAs. Simultaneously, ncRNAs also exert their influence by modulating the stability, splicing, translation, and other biological processes of m6A-related enzymes. The interplay between m6A and ncRNAs collectively contributes to the occurrence and progression of malignant tumors in humans. This review provides an overview of the interactions between m6A regulatory factors and ncRNAs and their impact on tumors.

microRNA-9a-5p disrupts the ELAVL1/VEGF axis to alleviate traumatic brain injury

Plasma microRNA (miR)-9 has been identified as a promising diagnostic biomarker for traumatic brain injury (TBI). This study aims to investigate the possible role and mechanisms of miR-9a-5p affecting TBI. Microarray-based gene expression profiling of TBI was used for screening differentially expressed miRNAs and genes. TBI rat models were established. miR-9a-5p, ELAVL1 and VEGF expression in the brain tissue of TBI rats was detected. The relationship among miR-9a-5p, ELAVL1 and VEGF was tested. TBI modeled rats were injected with miR-9a-5p-, ELAVL1 or VEGF-related sequences to identify their effects on TBI. miR-9a-5p was poorly expressed in the brain tissue of rats with TBI. ELAVL1 was a downstream target gene of miR-9a-5p, which could negatively regulate its expression. Enforced miR-9a-5p expression prevented brain tissue damage in TBI rats by targeting ELAVL1. Meanwhile, ELAVL1 could increase the expression of VEGF, which was highly expressed in the brain tissue of rats with TBI. In addition, ectopically expressed miR-9a-5p alleviated brain tissue damage in TBI rats by downregulating the ELAVL1/VEGF axis. Overall, miR-9a-5p can potentially reduce brain tissue damage in TBI rats by targeting ELAVL1 and down-regulating VEGF expression.

Etomidate inhibits tumor growth of glioblastoma by regulating M1 macrophage polarization

Glioblastoma (GBM) is a common primary central nervous system tumor. Although the multimodal integrated treatment for GBM has made great progress in recent years, the overall survival time of GBM is still short. Thus, novel treatments for GBM are worth further investigation and exploration. This study aimed to investigate the effects of etomidate on GBM tumor growth and the underlying mechanism. A xenograft tumor model was established and treated with etomidate to assess tumor growth. Immunohistochemistry (IHC) assay evaluated the positive rate of Ki67 cells in tumor tissues. Cell counting kit (CCK)-8 and EdU assays accessed the cell viability and proliferation. Immunofluorescence (IF) staining detected the distribution of macrophage markers in tumor tissues. The percentages of M1- and M2-like macrophages in tumor-associated macrophages (TAMs) and co-culture system (macrophages and GBM cells) were detected using flow cytometry. Macrophage polarization-related genes were measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Etomidate treatment inhibited the tumor growth, and increased the CD86+ cells but decreased the CD206+ cells in TAMs. The gene expression of M1 markers was increased in TAMs of etomidate-treated mice, whereas that of M2 markers was decreased. Moreover, etomidate treatment increased the number of CD86+ M1-like macrophages co-cultured with tumor cells but decreased that of CD206+ M2-like macrophages, with the upregulation of M1 markers and downregulation of M2 markers. Etomidate inhibited GBM tumor growth by promoting M1 macrophage polarization, suggesting a new insight into the clinical treatment of GBM.

The JMJD family of histone demethylase and their intimate links to cardiovascular disease

The incidence rate and mortality rate of cardiovascular disease rank first in the world. It is associated with various high-risk factors, and there is no single cause. Epigenetic modifications, such as DNA methylation or histone modification, actively participate in the initiation and development of cardiovascular diseases. Histone lysine methylation is a type of histone post-translational modification. The human Jumonji C domain (JMJD) protein family consists of more than 30 members. JMJD proteins participate in many key nuclear processes and play a key role in the specific regulation of gene expression, DNA damage and repair, and DNA replication. Importantly, increasing evidence shows that JMJD proteins are abnormally expressed in cardiovascular diseases, which may be a potential mechanism for the occurrence and development of these diseases. Here, we discuss the key roles of JMJD proteins in various common cardiovascular diseases. This includes histone lysine demethylase, which has been studied in depth, and less-studied JMJD members. Furthermore, we focus on the epigenetic changes induced by each JMJD member, summarize recent research progress, and evaluate their relationship with cardiovascular diseases and therapeutic potential.

Communication molecules (ncRNAs) mediate tumor-associated macrophage polarization and tumor progression

Non-coding RNAs play important roles in tumor cells and macrophages and participate in their communication as messengers. Non-coding RNAs have an impact in tumor cell proliferation, migration, and apoptosis, and they also regulate the differentiation and regulation of immune cells. In macrophages, they stimulate the polarization of macrophages into M1 or M2 by regulating proteins related to signaling pathways; in tumor cells, non-coding RNAs can enter macrophages through exosomes and affect the latter polarization. The polarization of macrophages further regulates the biological functions of cancer cells. The direction of macrophage polarization determines tumor progression, angiogenesis and drug resistance. This often creates a feedback loop. Non-coding RNAs act as bridges between tumor cells and macrophages to regulate the balance of the tumor microenvironment. We reviewed the signaling pathways related to macrophage polarization and the regulatory mechanisms of non-coding RNA in tumor-associated macrophages M1 and M2, and discussed the potential applications and prospects of exosome engineering.

Silencing of Jumonji domain-containing 1C inhibits the osteogenic differentiation of bone marrow mesenchymal stem cells via nuclear factor-κB signaling

BACKGROUND

Osteoporosis is a common metabolic bone disorder induced by an imbalance between osteoclastic activity and osteogenic activity. During osteoporosis, bone mesenchymal stem cells (BMSCs) exhibit an increased ability to differentiate into adipocytes and a decreased ability to differentiate into osteoblasts, resulting in bone loss. Jumonji domain-containing 1C (JMJD1C) has been demonstrated to suppress osteoclastogenesis.

AIM

To examine the effect of JMJD1C on the osteogenesis of BMSCs and the potential underlying mechanism.

METHODS

BMSCs were isolated from mouse bone marrow tissues. Oil Red O staining, Alizarin red staining, alkaline phosphatase staining and the expression of adipogenic and osteogenic-associated genes were assessed to determine the differentiation of BMSCs. Bone marrow-derived macrophages (BMMs) were incubated with receptor activator of nuclear factor-kappa Β ligand to induce osteoclast differentiation, and osteoclast differentiation was confirmed by tartrate-resistant acid phosphatase staining. Other related genes were measured via reverse transcription coupled to the quantitative polymerase chain reaction and western blotting. Enzyme-linked immunosorbent assays were used to measure the levels of inflammatory cytokines, including tumor necrosis factor alpha, interleukin-6 and interleukin-1 beta.

RESULTS

The osteogenic and adipogenic differentiation potential of BMSCs isolated from mouse bone marrow samples was evaluated. JMJD1C mRNA and protein expression was upregulated in BMSCs after osteoblast induction, while p-nuclear factor-κB (NF-κB) and inflammatory cytokines were not significantly altered. Knockdown of JMJD1C repressed osteogenic differentiation and enhanced NF-κB activation and inflammatory cytokine release in BMSCs. Moreover, JMJD1C expression decreased during BMM osteoclast differentiation.

CONCLUSION

The JMJD1C/NF-κB signaling pathway is potentially involved in BMSC osteogenic differentiation and may play vital roles in the pathogenesis of osteoporosis.

The role of N6-methyladenosine in macrophage polarization: A novel treatment strategy for non-alcoholic steatohepatitis

RNA methylation modifications, as a widespread type of modification in eukaryotic cells, especially N6-methyladenosine (m6A), are associated with many activities in organisms, including macrophage polarization and progression of non-alcoholic steatohepatitis (NASH). Macrophages in the liver are of diverse origin and complex phenotype, exhibiting different functions in development of NASH. In the review, we discuss the functions of m6A and m6A-related enzymes in macrophage polarization. Furthermore, we retrospect the role of macrophage polarization in NASH. Finally, we discuss the prospects of m6A in macrophages and NASH, and provide guidance for the treatment of NASH.

The RNA m6A writer METTL3 in tumor microenvironment: emerging roles and therapeutic implications

The tumor microenvironment (TME) is a heterogeneous ecosystem comprising cancer cells, immune cells, stromal cells, and various non-cellular components, all of which play critical roles in controlling tumor progression and response to immunotherapies. Methyltransferase-like 3 (METTL3), the core component of N 6-methyladenosine (m6A) writer, is frequently associated with abnormalities in the m6A epitranscriptome in different cancer types, impacting both cancer cells and the surrounding TME. While the impact of METTL3 on cancer cells has been extensively reviewed, its roles in TME and anti-cancer immunity have not been comprehensively summarized. This review aims to systematically summarize the functions of METTL3 in TME, particularly its effects on tumor-infiltrating immune cells. We also elaborate on the underlying m6A-dependent mechanism. Additionally, we discuss ongoing endeavors towards developing METTL3 inhibitors, as well as the potential of targeting METTL3 to bolster the efficacy of immunotherapy.

HMGB1-activated tumor-associated macrophages promote migration and invasion via NF-κB/IL-6 signaling in oral squamous cell carcinoma

Tumor-associated macrophages (TAMs) are a highly abundant cell population within the tumor microenvironment of oral squamous cell carcinomas (OSCC). Recent studies have identified an intricate cross-talk between cancer cells and macrophages in the tumor microenvironment. However, the underlying mechanism remains unclear. High-mobility group box 1 (HMGB1) was linked to metastasis and an unfavorable prognosis in head and neck squamous cell carcinoma. Furthermore, it was significantly upregulated in moderately differentiated OSCC tissues and the OSCC cell lines CAL27 and SCC9. HMGB1 knockdown impedes the ability of TAMs to induce invasion and migration of OSCC cells. Phenotypic changes in macrophages were measured after incubation of supernatant from OSCC cells transfected with HMGB1 siRNA or supplemented with recombinant HMGB1. HMGB1 induced M1 polarization of macrophages and the secretion of IL-6 via the NF-κB pathway, contributing to the OSCC malignant migration. HMGB1 originating from OSCC cells, along with its downstream signaling pathways, holds promise as a potential therapeutic target for mitigating metastasis and improving the survival rate of OSCC.

New insights into the regulation of METTL3 and its role in tumors

As one of the most abundant epigenetic modifications in RNA, N6-methyladenosine (m6A) affects RNA transcription, splicing, stability, and posttranscriptional translation. Methyltransferase-like 3 (METTL3), a key component of the m6A methyltransferase complex, dynamically regulates target genes expression through m6A modification. METTL3 has been found to play a critical role in tumorigenesis, tumor growth, metastasis, metabolic reprogramming, immune cell infiltration, and tumor drug resistance. As a result, the development of targeted drugs against METTL3 is becoming increasingly popular. This review systematically summarizes the factors that regulate METTL3 expression and explores the specific mechanisms by which METTL3 affects multiple tumor biological behaviors. We aim to provide fundamental support for tumor diagnosis and treatment, at the same time, to offer new ideas for the development of tumor-targeting drugs.

Ascorbic acid modulates immune responses through Jumonji-C domain containing histone demethylases and Ten eleven translocation (TET) methylcytosine dioxygenase

Ascorbic acid is a redox regulator in many physiological processes. Besides its antioxidant activity, many intriguing functions of ascorbic acid in the expression of immunoregulatory genes have been suggested. Ascorbic acid acts as a co-factor for the Fe+2 -containing α-ketoglutarate-dependent Jumonji-C domain-containing histone demethylases (JHDM) and Ten eleven translocation (TET) methylcytosine dioxygenasemediated epigenetic modulation. By influencing JHDM and TET, ascorbic acid facilitates the differentiation of double negative (CD4- CD8- ) T cells to double positive (CD4+ CD8+ ) T cells and of T-helper cells to different effector subsets. Ascorbic acid modulates plasma cell differentiation and promotes early differentiation of hematopoietic stem cells (HSCs) to NK cells. These findings indicate that ascorbic acid plays a significant role in regulating both innate and adaptive immune cells, opening up new research areas in Immunonutrition. Being a water-soluble vitamin and a safe micro-nutrient, ascorbic acid can be used as an adjunct therapy for many disorders of the immune system.

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.

The macrophage polarization by miRNAs and its potential role in the treatment of tumor and inflammation (Review)

The characteristics of monocyte/macrophage lineage are diversity and plasticity, mainly manifested by M1 and M2 subtypes in the body tissues, and playing different roles in the immunity. In the polarization process of macrophages, the classic molecular mechanism is related to sequential transcription factors. Whether in tumor or inflammatory local microenvironment, the pathological factors of the local microenvironment often affect the polarization of M1 and M2 macrophages, and participate in the occurrence and development of these pathological processes. In recent years, a growing number of research results demonstrated that non‑coding RNA (ncRNA) also participates in the polarization process of macrophages, in addition to traditional cytokines and transcriptional regulation signal pathway molecules. Among numerous ncRNAs, microRNAs (miRNAs) have attracted more attention from scholars both domestically and internationally, and significant progress has been made in basic and clinical research. Therefore, for improved understanding of the molecular mechanism of miRNAs in macrophage polarization and analysis of the potential value of this regulatory pathway in tumor and inflammatory intervention therapy, a comprehensive review of the progress of relevant literature research was conducted and some viewpoints and perspectives were proposed.

The Importance of M1-and M2-Polarized Macrophages in Glioma and as Potential Treatment Targets

Glioma is the most common and malignant tumor of the central nervous system. Glioblastoma (GBM) is the most aggressive glioma, with a poor prognosis and no effective treatment because of its high invasiveness, metabolic rate, and heterogeneity. The tumor microenvironment (TME) contains many tumor-associated macrophages (TAMs), which play a critical role in tumor proliferation, invasion, metastasis, and angiogenesis and indirectly promote an immunosuppressive microenvironment. TAM is divided into tumor-suppressive M1-like (classic activation of macrophages) and tumor-supportive M2-like (alternatively activated macrophages) polarized cells. TAMs exhibit an M1-like phenotype in the initial stages of tumor progression, and along with the promotion of lysing tumors and the functions of T cells and NK cells, tumor growth is suppressed, and they rapidly transform into M2-like polarized macrophages, which promote tumor progression. In this review, we discuss the mechanism by which M1- and M2-polarized macrophages promote or inhibit the growth of glioblastoma and indicate the future directions for treatment.

Emerging role of METTL3 in inflammatory diseases: mechanisms and therapeutic applications

Despite improvements in modern medical therapies, inflammatory diseases, such as atherosclerosis, diabetes, non-alcoholic fatty liver, chronic kidney diseases, and autoimmune diseases have high incidence rates, still threaten human health, and represent a huge financial burden. N6-methyladenosine (m6A) modification of RNA contributes to the pathogenesis of various diseases. As the most widely discussed m6A methyltransferase, the pathogenic role of METTL3 in inflammatory diseases has become a research hotspot, but there has been no comprehensive review of the topic. Here, we summarize the expression changes, modified target genes, and pathogenesis related to METTL3 in cardiovascular, metabolic, degenerative, immune, and infectious diseases, as well as tumors. In addition to epithelial cells, endothelial cells, and fibroblasts, METTL3 also regulates the function of inflammation-related immune cells, including macrophages, neutrophils, dendritic cells, Th17 cells, and NK cells. Regarding therapeutic applications, METTL3 serves as a target for the treatment of inflammatory diseases with natural plant drug components, such as emodin, cinnamaldehyde, total flavonoids of Abelmoschus manihot, and resveratrol. This review focuses on recent advances in the initiation, development, and therapeutic application of METTL3 in inflammatory diseases. Knowledge of the specific regulatory mechanisms involving METTL3 can help to deepen understanding of inflammatory diseases and lay the foundation for the development of precisely targeted drugs to address inflammatory processes.

Histone demethylases in the regulation of immunity and inflammation

Pathogens or danger signals trigger the immune response. Moderate immune response activation removes pathogens and avoids excessive inflammation and tissue damage. Histone demethylases (KDMs) regulate gene expression and play essential roles in numerous physiological processes by removing methyl groups from lysine residues on target proteins. Abnormal expression of KDMs is closely associated with the pathogenesis of various inflammatory diseases such as liver fibrosis, lung injury, and autoimmune diseases. Despite becoming exciting targets for diagnosing and treating these diseases, the role of these enzymes in the regulation of immune and inflammatory response is still unclear. Here, we review the underlying mechanisms through which KDMs regulate immune-related pathways and inflammatory responses. In addition, we also discuss the future applications of KDMs inhibitors in immune and inflammatory diseases.

Deciphering glioma epitranscriptome: focus on RNA modifications

Gliomas are highly malignant tumors accounting for the majority of brain neoplasms. They are characterized by nuclear atypia, high mitotic rate and cellular polymorphism that often contributes to aggressiveness and resistance to standard therapy. They often associate with challenging treatment approaches and poor outcomes. New treatment strategies or regimens to improve the efficacy of glioma treatment require a deeper understanding of glioma occurrence and development as well as elucidation of their molecular biological characteristics. Recent studies have revealed RNA modifications as a key regulatory mechanism involved in tumorigenesis, tumor progression, immune regulation, and response to therapy. The present review discusses research advances on several RNA modifications involved in glioma progression and tumor microenvironment (TME) immunoregulation as well as in the development of adaptive drug resistance, summarizing current progress on major RNA modification targeting strategies.

Role of N6-methyladenosine modification in central nervous system diseases and related therapeutic agents

N6-methyladenosine (m6A) is a ubiquitous mRNA modification in eukaryotes. m6A occurs through the action of methyltransferases, demethylases, and methylation-binding proteins. m6A methylation of RNA is associated with various neurological disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), depression, cerebral apoplexy, brain injury, epilepsy, cerebral arteriovenous malformations, and glioma. Furthermore, recent studies report that m6A-related drugs have attracted considerable concerns in the therapeutic areas of neurological disorders. Here, we mainly summarized the role of m6A modification in neurological diseases and the therapeutic potential of m6A-related drugs. The aim of this review is expected to be useful to systematically assess m6A as a new potential biomarker and develop innovative modulators of m6A for the amelioration and treatment of neurological disorders.

Crosstalk between Noncoding RNAs and the Epigenetics Machinery in Pediatric Tumors and Their Microenvironment

According to the World Health Organization, every year, an estimated 400,000+ new cancer cases affect children under the age of 20 worldwide. Unlike adult cancers, pediatric cancers develop very early in life due to alterations in signaling pathways that regulate embryonic development, and environmental factors do not contribute much to cancer development. The highly organized complex microenvironment controlled by synchronized gene expression patterns plays an essential role in the embryonic stages of development. Dysregulated development can lead to tumor initiation and growth. The low mutational burden in pediatric tumors suggests the predominant role of epigenetic changes in driving the cancer phenotype. However, one more upstream layer of regulation driven by ncRNAs regulates gene expression and signaling pathways involved in the development. Deregulation of ncRNAs can alter the epigenetic machinery of a cell, affecting the transcription and translation profiles of gene regulatory networks required for cellular proliferation and differentiation during embryonic development. Therefore, it is essential to understand the role of ncRNAs in pediatric tumor development to accelerate translational research to discover new treatments for childhood cancers. This review focuses on the role of ncRNA in regulating the epigenetics of pediatric tumors and their tumor microenvironment, the impact of their deregulation on driving pediatric tumor progress, and their potential as effective therapeutic targets.

JMJD1C promotes smooth muscle cell proliferation by activating glycolysis in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a chronic disorder characterized by hyperproliferation of pulmonary arterial smooth muscle cells (PASMCs). JMJD1C, a member of the Jumonji domain containing C (JMJC) histone demethylase family, contributes to cardiovascular dysfunction. However, the role of JMJD1C in PAH remains unknown. Mice were exposed to hypoxia to mimic several features associated with PAH clinically. We found that JMJD1C was highly expressed in the lungs of mice after hypoxia exposure. JMJD1C knockdown ameliorated hypoxia-induced right ventricular remodeling and thickening of the pulmonary arterial wall. PASMC hyperproliferation and resistance to apoptosis in mice exposed to hypoxia were suppressed by JMJD1C inhibition. We demonstrated that JMJD1C silencing reduced glycolytic enzymes (HK2, PGK1 and LDHA) and lactate overaccumulation in the lungs of mice exposed to hypoxia. In vitro, hypoxia-induced hyperproliferation and activated glycolytic processes in mouse PASMCs were impaired by JMJD1C knockdown. In addition, the activation of STAT3 signaling by hypoxia was suppressed by JMJD1C silencing both in vivo and in vitro. The overexpression of STAT3 reversed the inhibitory effect of JMJD1C depletion on proliferation and glycolysis in PASMCs under hypoxia. Thus, JMJD1C induces glycolytic processes by activating STAT3 signaling to promote PASMC proliferation and pulmonary vascular remodeling, suggesting the potential role of JMJD1C in regulating the metabolic program and vascular remodeling in PAH.

Discovery of Targets for Immune-Metabolic Antitumor Drugs Identifies Estrogen-Related Receptor Alpha

Drugs that kill tumors through multiple mechanisms have the potential for broad clinical benefits. Here, we first developed an in silico multiomics approach (BipotentR) to find cancer cell-specific regulators that simultaneously modulate tumor immunity and another oncogenic pathway and then used it to identify 38 candidate immune-metabolic regulators. We show the tumor activities of these regulators stratify patients with melanoma by their response to anti-PD-1 using machine learning and deep neural approaches, which improve the predictive power of current biomarkers. The topmost identified regulator, ESRRA, is activated in immunotherapy-resistant tumors. Its inhibition killed tumors by suppressing energy metabolism and activating two immune mechanisms: (i) cytokine induction, causing proinflammatory macrophage polarization, and (ii) antigen-presentation stimulation, recruiting CD8+ T cells into tumors. We also demonstrate a wide utility of BipotentR by applying it to angiogenesis and growth suppressor evasion pathways. BipotentR (http://bipotentr.dfci.harvard.edu/) provides a resource for evaluating patient response and discovering drug targets that act simultaneously through multiple mechanisms.

SIGNIFICANCE

BipotentR presents resources for evaluating patient response and identifying targets for drugs that can kill tumors through multiple mechanisms concurrently. Inhibition of the topmost candidate target killed tumors by suppressing energy metabolism and effects on two immune mechanisms. This article is highlighted in the In This Issue feature, p. 517.

Exosomal miRNAs-mediated macrophage polarization and its potential clinical application

Macrophages are highly heterogeneous and plastic immune cells that play an important role in the fight against pathogenic microorganisms and tumor cells. After different stimuli, macrophages can polarize to the M1 phenotype to show a pro-inflammatory effect and the M2 phenotype to show an anti-inflammatory effect. The balance of macrophage polarization is highly correlated with disease progression, and therapeutic approaches to reprogram macrophages by targeting macrophage polarization are feasible. There are a large number of exosomes in tissue cells, which can transmit information between cells. In particular, microRNAs (miRNAs) in the exosomes can regulate the polarization of macrophages and further affect the progression of various diseases. At the same time, exosomes are also effective "drug" carriers, laying the foundation for the clinical application of exosomes. This review describes some pathways involved in M1/M2 macrophage polarization and the effects of miRNA carried by exosomes from different sources on the polarization of macrophages. Finally, the application prospects and challenges of exosomes/exosomal miRNAs in clinical treatment are also discussed.

N6-methyladenosine in macrophage function: a novel target for metabolic diseases

N6-methyladenosine (m⁶A) is one of the most prevalent internal transcriptional modifications. Evidence has highlighted changes in m⁶A in metabolic disorders and various metabolic diseases. However, the precise mechanisms of these m⁶A changes in such conditions are not understood. Macrophages are crucial for the innate immune system and exert either beneficial or harmful roles in metabolic disease. Notably, m⁶A was found to be closely related to macrophage phenotype and dysfunction. In this review, we summarize m⁶A in macrophage function from the perspective of macrophage development, activation, and polarization, pyroptosis, and metabolic disorders. Furthermore, we discuss how m⁶A-mediated macrophage function affects metabolic diseases, including atherosclerosis and nonalcoholic fatty liver disease (NAFLD). Finally, we discuss challenges and prospects for m⁶A in macrophage and metabolic diseases with the aim of providing guidance for the treatment of metabolic diseases.

Recent Advances in RNA m6A Modification in Solid Tumors and Tumor Immunity

An analogous field to epigenetics is referred to as epitranscriptomics, which focuses on the study of post-transcriptional chemical modifications in RNA. RNA molecules, including mRNA, tRNA, rRNA, and other non-coding RNA molecules, can be edited with numerous modifications. The most prevalent modification in eukaryotic mRNA is N6-methyladenosine (m6A), which is a reversible modification found in over 7000 human genes. Recent technological advances have accelerated the characterization of these modifications, and they have been shown to play important roles in many biological processes, including pathogenic processes such as cancer. In this chapter, we discuss the role of m6A mRNA modification in cancer with a focus on solid tumor biology and immunity. m6A RNA methylation and its regulatory proteins can play context-dependent roles in solid tumor development and progression by modulating RNA metabolism to drive oncogenic or tumor-suppressive cellular pathways. m6A RNA methylation also plays dynamic roles within both immune cells and tumor cells to mediate the anti-tumor immune response. Finally, an emerging area of research within epitranscriptomics studies the role of m6A RNA methylation in promoting sensitivity or resistance to cancer therapies, including chemotherapy, targeted therapy, and immunotherapy. Overall, our understanding of m6A RNA methylation in solid tumors has advanced significantly, and continued research is needed both to fill gaps in knowledge and to identify potential areas of focus for therapeutic development.

N6-methyladenosine RNA methylation regulator-related alternative splicing gene signature as prognostic predictor and in immune microenvironment characterization of patients with low-grade glioma

Background: N6-methyladenosine (m6A) RNA methylation is an important epigenetic modification affecting alternative splicing (AS) patterns of genes to regulate gene expression. AS drives protein diversity and its imbalance may be an important factor in tumorigenesis. However, the clinical significance of m6A RNA methylation regulator-related AS in the tumor microenvironment has not been investigated in low-grade glioma (LGG).

Methods: We used 12 m6A methylation modulatory genes (WTAP, FTO, HNRNPC, YTHDF2, YTHDF1, YTHDC2, ALKBH5, YTHDC1, ZC3H13, RBM15, METTL14, and METTL3) from The Cancer Genome Atlas (TCGA) database as well as the TCGA-LGG (n = 502) dataset of AS events and transcriptome data. These data were downloaded and subjected to machine learning, bioinformatics, and statistical analyses, including gene ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Univariate Cox, the Least Absolute Shrinkage and Selection Operator (LASSO), and multivariable Cox regression were used to develop prognostic characteristics. Prognostic values were validated using Kaplan-Maier survival analysis, proportional risk models, ROC curves, and nomograms. The ESTIMATE package, TIMER database, CIBERSORT method, and ssGSEA algorithm in the R package were utilized to explore the role of the immune microenvironment in LGG. Lastly, an AS-splicing factor (SF) regulatory network was examined in the case of considering the role of SFs in regulating AS events.

Results: An aggregate of 3,272 m6A regulator-related AS events in patients with LGG were screened using six machine learning algorithms. We developed eight AS prognostic characteristics based on splice subtypes, which showed an excellent prognostic prediction performance. Furthermore, quantitative prognostic nomograms were developed and showed strong validity in prognostic prediction. In addition, prognostic signatures were substantially associated with tumor immune microenvironment diversity, ICB-related genes, and infiltration status of immune cell subtypes. Specifically, UGP2 has better promise as a prognostic factor for LGG. Finally, splicing regulatory networks revealed the potential functions of SFs.

Conclusion: The present research offers a novel perspective on the role of AS in m6A methylation. We reveal that m6A methylation regulator-related AS events can mediate tumor progression through the immune-microenvironment, which could serve as a viable biological marker for clinical stratification of patients with LGG so as to optimize treatment regimens.

Crosstalk between macrophages and innate lymphoid cells (ILCs) in diseases

Innate lymphoid cells (ILCs) and macrophages are tissue-resident cells that play important roles in tissue-immune homeostasis and immune regulation. ILCs are mainly distributed on the barrier surfaces of mammals to ensure immunity or tissue homeostasis following host, microbial, or environmental stimulation. Their complex relationships with different organs enable them to respond quickly to disturbances in environmental conditions and organ homeostasis, such as during infections and tissue damage. Gradually emerging evidence suggests that ILCs also play complex and diverse roles in macrophage development, homeostasis, polarization, inflammation, and viral infection. In turn, macrophages also determine the fate of ILCs to some extent, which indicates that network crossover between these interactions is a key determinant of the immune response. More work is needed to better define the crosstalk of ILCs with macrophages in different tissues and demonstrate how it is affected during inflammation and other diseases. Here, we summarize current research on the functional interactions between ILCs and macrophages and consider the potential therapeutic utility of these interactions for the benefit of human health.

The Potential Value of m6A RNA Methylation in the Development of Cancers Focus on Malignant Glioma

N6-methyladenosine (m6A) RNA methylation is an epigenetic modification that has emerged in the last few years and has received increasing attention as the most abundant internal RNA modification in eukaryotic cells. m6A modifications affect multiple aspects of RNA metabolism, and m6A methylation has been shown to play a critical role in the progression of multiple cancers through a variety of mechanisms. This review summarizes the mechanisms by which m6A RNA methylation induced peripheral cancer cell progression and its potential role in the infiltration of immune cell of the glioblastoma microenvironment and novel immunotherapy. Assessing the pattern of m6A modification in glioblastoma will contribute to improving our understanding of microenvironmental infiltration and novel immunotherapies, and help in developing immunotherapeutic strategies.