MiR-495 regulates macrophage M1/M2 polarization and insulin resistance in high-fat diet-fed mice via targeting FTO

m6A epitranscriptomic modification of inflammation in cardiovascular disease

Cardiovascular disease is currently the number one cause of death endangering human health. There is currently a large body of research showing that the development of cardiovascular disease and its complications is often accompanied by inflammatory processes. In recent years, epitranscriptional modifications have been shown to be involved in regulating the pathophysiological development of inflammation in cardiovascular diseases, with 6-methyladenine being one of the most common RNA transcriptional modifications. In this review, we link different cardiovascular diseases, including atherosclerosis, heart failure, myocardial infarction, and myocardial ischemia-reperfusion, with inflammation and describe the regulatory processes involved in RNA methylation. Advances in RNA methylation research have revealed the close relationship between the regulation of transcriptome modifications and inflammation in cardiovascular diseases and brought potential therapeutic targets for disease diagnosis and treatment. At the same time, we also discussed different cell aspects. In addition, in the article we also describe the different application aspects and clinical pathways of RNA methylation therapy. In summary, this article reviews the mechanism, regulation and disease treatment effects of m6A modification on inflammation and inflammatory cells in cardiovascular diseases in recent years. We will discuss issues facing the field and new opportunities that may be the focus of future research.

Deciphering the performance of macrophages in tumour microenvironment: a call for precision immunotherapy

Macrophages infiltrating tumour tissues or residing in the microenvironment of solid tumours are known as tumour-associated macrophages (TAMs). These specialized immune cells play crucial roles in tumour growth, angiogenesis, immune regulation, metastasis, and chemoresistance. TAMs encompass various subpopulations, primarily classified into M1 and M2 subtypes based on their differentiation and activities. M1 macrophages, characterized by a pro-inflammatory phenotype, exert anti-tumoural effects, while M2 macrophages, with an anti-inflammatory phenotype, function as protumoural regulators. These highly versatile cells respond to stimuli from tumour cells and other constituents within the tumour microenvironment (TME), such as growth factors, cytokines, chemokines, and enzymes. These stimuli induce their polarization towards one phenotype or another, leading to complex interactions with TME components and influencing both pro-tumour and anti-tumour processes.This review comprehensively and deeply covers the literature on macrophages, their origin and function as well as the intricate interplay between macrophages and the TME, influencing the dual nature of TAMs in promoting both pro- and anti-tumour processes. Moreover, the review delves into the primary pathways implicated in macrophage polarization, examining the diverse stimuli that regulate this process. These stimuli play a crucial role in shaping the phenotype and functions of macrophages. In addition, the advantages and limitations of current macrophage based clinical interventions are reviewed, including enhancing TAM phagocytosis, inducing TAM exhaustion, inhibiting TAM recruitment, and polarizing TAMs towards an M1-like phenotype. In conclusion, while the treatment strategies targeting macrophages in precision medicine show promise, overcoming several obstacles is still necessary to achieve an accessible and efficient immunotherapy.

RNA modifications in cellular metabolism: implications for metabolism-targeted therapy and immunotherapy

Cellular metabolism is an intricate network satisfying bioenergetic and biosynthesis requirements of cells. Relevant studies have been constantly making inroads in our understanding of pathophysiology, and inspiring development of therapeutics. As a crucial component of epigenetics at post-transcription level, RNA modification significantly determines RNA fates, further affecting various biological processes and cellular phenotypes. To be noted, immunometabolism defines the metabolic alterations occur on immune cells in different stages and immunological contexts. In this review, we characterize the distribution features, modifying mechanisms and biological functions of 8 RNA modifications, including N6-methyladenosine (m6A), N6,2'-O-dimethyladenosine (m6Am), N1-methyladenosine (m1A), 5-methylcytosine (m5C), N4-acetylcytosine (ac4C), N7-methylguanosine (m7G), Pseudouridine (Ψ), adenosine-to-inosine (A-to-I) editing, which are relatively the most studied types. Then regulatory roles of these RNA modification on metabolism in diverse health and disease contexts are comprehensively described, categorized as glucose, lipid, amino acid, and mitochondrial metabolism. And we highlight the regulation of RNA modifications on immunometabolism, further influencing immune responses. Above all, we provide a thorough discussion about clinical implications of RNA modification in metabolism-targeted therapy and immunotherapy, progression of RNA modification-targeted agents, and its potential in RNA-targeted therapeutics. Eventually, we give legitimate perspectives for future researches in this field from methodological requirements, mechanistic insights, to therapeutic applications.

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.

Involvement of miR-495 in the skin pigmentation of rainbow trout (Oncorhynchus mykiss) through the regulation of mc1r

MicroRNAs (miRNAs) play crucial roles in skin pigmentation in animals. Rainbow trout (Oncorhynchus mykiss) is a key economic fish species worldwide, and skin color directly affects its economic value. However, the functions of miRNAs in rainbow trout skin pigmentation remain largely unknown. Herein, we overexpressed and silenced miR-495 in vitro and in vivo to investigate its functions. The analysis of spatial and temporal expression patterns suggested that miR-495 is a potential regulator during the process of skin pigmentation. In vitro, mc1r was validated as a direct target for miR-495 by dual-luciferase reporter assay, and overexpression of miR-495 significantly inhibited mc1r expression; in contrast, mc1r and its downstream gene mitf levels were markedly upregulated by decreased miR-495. In vivo, overexpressed miR-495 by injecting agomiR-495 led to a substantial decrease in the expression of mc1r and mitf in dorsal skin and liver, while the opposite results were obtained after miR-495 silencing by antagomiR-495. These findings suggested that miR-495 can target mc1r to regulate rainbow trout skin pigmentation, which provide a potential basis for using miRNAs as target drugs to treat pigmentation disorders and melanoma.

m6A demethylase FTO and osteoporosis: potential therapeutic interventions

Osteoporosis is a common bone disease, characterized by a descent in bone mass due to the dysregulation of bone homeostasis. Although different studies have identified an association between osteoporosis and epigenetic alterations in osteogenic genes, the mechanisms of osteoporosis remain unclear. N6-methyladenosine (m6A) modification is a methylated adenosine nucleotide, which regulates the translocation, exporting, translation, and decay of RNA. FTO is the first identified m6A demethylase, which eliminates m6A modifications from RNAs. Variation in FTO disturbs m6A methylation in RNAs to regulate cell proliferation, differentiation, and apoptosis. Besides, FTO as an obesity-associated gene, also affects osteogenesis by regulating adipogenesis. Pharmacological inhibition of FTO markedly altered bone mass, bone mineral density and the distribution of adipose tissue. Small molecules which modulate FTO function are potentially novel remedies to the treatment of osteoporosis by adjusting the m6A levels. This article reviews the roles of m6A demethylase FTO in regulating bone metabolism and osteoporosis.

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.

m6 A demethylase Fto regulates the TNF-α-induced inflammatory response in cementoblasts

OBJECTIVE

Apical periodontitis is the most frequently occurring pathological lesion. Fat mass and obesity-associated protein (Fto) is the first identified RNA N6-methyladenosine demethylase. However, whether Fto regulates apical periodontitis remains unclear. This study aimed to explore the mechanisms of Fto in the tumor necrosis factor-α (TNF-α)-induced inflammatory response.

MATERIALS AND METHODS

We established an apical periodontitis model. An immortalized cementoblast cell line (OCCM-30) cells were exposed to TNF-α. Fto, Il6, Mcp1, and Mmp9 expressions were assessed by qRT-PCR. We knocked down Fto using lentiviruses and detected TNF-α-induced inflammation-related gene expressions and mRNA stability.

RESULTS

Mice with apical periodontitis showed downregulation of Fto expression. OCCM-30 cells exposed to TNF-α showed an upregulation of inflammation-related genes with a decrease in Fto. Furthermore, knockdown of Fto promoted the expressions of Il6, Mcp1, and Mmp9 in TNF-α-treated OCCM-30 cells as compared with negative control cells, whereas it did not affect the mRNA stability. Interestingly, Fto knockdown activated the p65, p38, and ERK1/2 pathways, and it slightly activated the JNK signaling pathway after TNF-α administration in OCCM-30 cells.

CONCLUSION

A TNF-α-induced decrease in the expression of Fto might play a critical role in the inflammatory response in cementoblasts, and knockdown of Fto might upregulate the inflammatory response.

Biomarkers of obesity-mediated insulin resistance: focus on microRNAs

Obesity and metabolic syndromes are becoming increasingly prevalent worldwide. Insulin resistance (IR) is a common complication of obesity. However, IR occurrence varies across individuals with obesity and may involve epigenetic factors. To rationalize the allocation of healthcare resources, biomarkers for the early risk stratification of individuals with obesity should be identified. MicroRNAs (miRNAs) are closely associated with metabolic diseases and involved in epigenetic regulation. In this review, we have summarized the changes in miRNA expression in the peripheral circulation and tissues of patients and animals with obesity-associated IR over the last 5 years and identified several candidate biomarkers that predict obesity-related IR. There are areas for improvement in existing studies. First, more than the predictive validity of a single biomarker is required, and a biomarker panel needs to be formed. Second, miRNAs are often studied in isolation and do not form a network of signaling pathways. We believe that early biomarkers can help clinicians accurately predict individuals prone to obesity-related IR at an early stage. Epigenetic regulation may be one of the underlying causes of different clinical outcomes in individuals with obesity. Future studies should focus on objectively reflecting the differences in miRNA profile expression in individuals with obesity-related IR, which may help identify more reliable biomarkers. Understanding the metabolic pathways of these miRNAs can help design new metabolic risk prevention and management strategies, and support the development of drugs to treat obesity and metabolic disorders.

Non-coding RNAs and type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a worldwide disease with rapidly increasing prevalence. This complex disorder caused by interplay between genetic predisposition factors, early developmental elements, diet and inactive lifestyle. Several researches have shown impact of long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) in the pathogenesis of this disorder. Several miRNAs such as miR-126, miR-222-3p, miR-182, let-7b-5p, and miR-1-3p have been down-regulated in different biological sources of patients with T2DM. Some other miRNAs including miR-21, miR-30d, miR-148a-3p, miR-146b and miR-486 have the opposite trends. In addition, a number of lncRNAs such as LY86-AS, HCG27_201, VIM-AS1, CTBP1-AS2, CASC2, GAS5, LINC-PINT, and MALAT1 have been altered in the peripheral blood, serum samples or tissues obtained from patients with T2DM. Taken together, both miRNAs and lncRNAs contribute to the development of T2DM and might be applied as markers or therapeutic molecules for this disorder.

The Role of m6A Modifications in B-Cell Development and B-Cell-Related Diseases

B cells are a class of professional antigen-presenting cells that produce antibodies to mediate humoral immune response and participate in immune regulation. m⁶A modification is the most common RNA modification in mRNA; it involves almost all aspects of RNA metabolism and can affect RNA splicing, translation, stability, etc. This review focuses on the B-cell maturation process as well as the role of three m⁶A modification-related regulators-writer, eraser, and reader-in B-cell development and B-cell-related diseases. The identification of genes and modifiers that contribute to immune deficiency may shed light on regulatory requirements for normal B-cell development and the underlying mechanism of some common diseases.

MicroRNAs as Biomarkers for Coronary Artery Disease Related to Type 2 Diabetes Mellitus-From Pathogenesis to Potential Clinical Application

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease with still growing incidence among adults and young people worldwide. Patients with T2DM are more susceptible to developing coronary artery disease (CAD) than non-diabetic individuals. The currently used diagnostic methods do not ensure the detection of CAD at an early stage. Thus, extensive research on non-invasive, blood-based biomarkers is necessary to avoid life-threatening events. MicroRNAs (miRNAs) are small, endogenous, non-coding RNAs that are stable in human body fluids and easily detectable. A number of reports have highlighted that the aberrant expression of miRNAs may impair the diversity of signaling pathways underlying the pathophysiology of atherosclerosis, which is a key player linking T2DM with CAD. The preclinical evidence suggests the atheroprotective and atherogenic influence of miRNAs on every step of T2DM-induced atherogenesis, including endothelial dysfunction, endothelial to mesenchymal transition, macrophage activation, vascular smooth muscle cells proliferation/migration, platelet hyperactivity, and calcification. Among the 122 analyzed miRNAs, 14 top miRNAs appear to be the most consistently dysregulated in T2DM and CAD, whereas 10 miRNAs are altered in T2DM, CAD, and T2DM-CAD patients. This up-to-date overview aims to discuss the role of miRNAs in the development of diabetic CAD, emphasizing their potential clinical usefulness as novel, non-invasive biomarkers and therapeutic targets for T2DM individuals with a predisposition to undergo CAD.

Adipose tissue macrophage in obesity-associated metabolic diseases

Adipose tissue macrophage (ATM) has been appreciated for its critical contribution to obesity-associated metabolic diseases in recent years. Here, we discuss the regulation of ATM on both metabolic homeostatsis and dysfunction. In particular, the macrophage polarization and recruitment as well as the crosstalk between ATM and adipocyte in thermogenesis, obesity, insulin resistance and adipose tissue fibrosis have been reviewed. A better understanding of how ATM regulates adipose tissue remodeling may provide novel therapeutic strategies against obesity and associated metabolic diseases.

m6A Methylation in Cardiovascular Diseases: From Mechanisms to Therapeutic Potential

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality worldwide. Recent studies have shown that n6-methyladenosine (m6A) plays a major role in cardiovascular homeostasis and pathophysiology. These studies have confirmed that m6A methylation affects the pathophysiology of cardiovascular diseases by regulating cellular processes such as differentiation, proliferation, inflammation, autophagy, and apoptosis. Moreover, plenty of research has confirmed that m6A modification can delay the progression of CVD via the post-transcriptional regulation of RNA. However, there are few available summaries of m6A modification regarding CVD. In this review, we highlight advances in CVD-specific research concerning m6A modification, summarize the mechanisms underlying the involvement of m6A modification during the development of CVD, and discuss the potential of m6A modification as a therapeutic target of CVD.

Epigenetic Regulation of Estrogen Receptor Genes' Expressions in Adipose Tissue in the Course of Obesity

Estrogen affects adipose tissue function. Therefore, this study aimed at assessing changes in the transcriptional activity of estrogen receptor (ER) α and β genes (ESR1 and ESR2, respectively) in the adipose tissues of obese individuals before and after weight loss and verifying whether epigenetic mechanisms were involved in this phenomenon. ESR1 and ESR2 mRNA and miRNA levels were evaluated using real-time PCR in visceral (VAT) and subcutaneous adipose tissue (SAT) of 78 obese (BMI > 40 kg/m2) and 31 normal-weight (BMI = 20−24.9 kg/m2) individuals and in 19 SAT samples from post-bariatric patients. ESR1 and ESR2 methylation status was studied using the methylation-sensitive digestion/real-time PCR method. Obesity was associated with a decrease in mRNA levels of both ERs in SAT (p < 0.0001) and ESR2 in VAT (p = 0.0001), while weight loss increased ESR transcription (p < 0.0001). Methylation levels of ESR1 and ESR2 promoters were unaffected. However, ESR1 mRNA in the AT of obese subjects correlated negatively with the expression of hsa-miR-18a-5p (rs = −0.444), hsa-miR-18b-5p (rs = −0.329), hsa-miR-22-3p (rs = −0.413), hsa-miR-100-5p (rs = −0.371), and hsa-miR-143-5p (rs = −0.289), while the expression of ESR2 in VAT correlated negatively with hsa-miR-576-5p (rs = −0.353) and in SAT with hsa-miR-495-3p (rs = −0.308). In conclusion, obesity-associated downregulation of ER mRNA levels in adipose tissue may result from miRNA interference.

Long non-coding RNA-non-coding RNA activated by DNA damage inhibition suppresses hepatic stellate cell activation via microRNA-495-3p/sphingosine 1-phosphate receptor 3 axis

Hepatic fibrosis is a damage repair response caused by multiple factors. A growing body of research suggests that long non-coding RNAs (lncRNAs) are involved in a wide range of biological processes, and thus regulate disease progression, including hepatic fibrosis. In this study, we investigated the mechanisms of the long non-coding RNA-non-coding RNA activated by DNA damage (NORAD) in modulating hepatic fibrosis development. Platelet-derived growth factor-BB (PDGF-BB) was used to activate LX-2 hepatic stellate cells (HSCs). The expression of NORAD and microRNA (miR)-495-3p was determined by quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The effects of PDGF-BB on LX-2 cell viability, migration, invasion, and apoptosis were evaluated using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), Transwell, flow cytometry, and Western blot assays. The activation of HSCs was further verified by examining the expression of the typical markers, alpha smooth muscle actin (α-SMA) and collagen I (Col1α1), using qRT-PCR and Western blot assays. StarBase and dual-luciferase reporter assays were used to assess the binding relationship between miR-495-3p and NORAD. The NORAD levels remarkably increased, whereas the miR-495-3p levels decreased, in PDGF-BB-treated LX-2 cells. miR-495-3p was a putative downstream target of NORAD. NORAD silencing played an anti-fibrotic role by targeting miR-495-3p; this was accomplished by hindering PDGF-BB-treated LX-2 cell viability, migration, and invasion, decreasing the levels of α-SMA and Col1α1, and promoting apoptosis. miR-495-3p protected against hepatic fibrosis by inhibiting sphingosine 1-phosphate receptor 3 (S1PR3) expression. In summary, NORAD silencing inhibited hepatic fibrosis by suppressing HSC activation via the miR-495-3p/S1PR3 axis.

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.

Transcriptomic Analysis Exploring the Molecular Mechanisms of Hanchuan Zupa Granules in Alleviating Asthma in Rat

Objective

To investigate the molecular mechanisms of HCZP treatment of asthma.

Materials and Methods

Thirty Sprague Dawley (SD) rats were divided into normal, asthma, and HCZP groups (n = 10). The asthma model was sensitized by 1 mg ovalbumin (OVA)/aluminum hydroxide Al(OH)₃mixture and then challenged with 1% aerosolized OVA for four weeks. Rats in the HCZP group received 10.08 g/kg/d HCZP for four weeks during OVA challenge. Then, lung tissues of rats in each group were collected for RNA sequencing. Moreover, the expression level of some core genes was detected by using western blotting and immunohistochemistry.

Results

Inflammatory cell infiltration and pathological damage of the lungs improved in the HCZP group. Compared with the asthma group (0.049 ± 0.002 mm²/mm; 0.036 ± 0.006 mm²/mm; and 0.014 ± 0.001 mm²/mm), total wall thickness (0.042 ± 0.001 mm²/mm), inner wall thickness (0.013 ± 0.001 mm²/mm), and smooth muscle layer thickness (0.012 ± 0.001 mm²/mm) significantly decreased in the HCZP group. Bioinformatics analysis showed that hub genes such as bradykinin receptor B2 (Bdkrb2) and CD4 molecule (Cd4) had different expression patterns between model and HCZP groups. Two transcription factors, forkhead box Q1 (Foxq1) and nuclear factor of activated T cells 2 (Nfatc2), served important regulatory roles in asthma. Compared with the model group, Bdkrb2 protein expression increased and Nfatc2 protein expression decreased in the HCZP group. Discussion and Conclusion. HCZP could alleviate asthma via regulating the expression of several hub genes, which might serve as therapeutic targets for asthma. However, the mechanism of these genes will be studied in the future.

N6-Methyladenosine RNA Modification in Inflammation: Roles, Mechanisms, and Applications

N6-methyladenosine (m6A) is the most prevalent internal mRNA modification. m6A can be installed by the methyltransferase complex and removed by demethylases, which are involved in regulating post-transcriptional expression of target genes. RNA methylation is linked to various inflammatory states, including autoimmunity, infection, metabolic disease, cancer, neurodegenerative diseases, heart diseases, and bone diseases. However, systematic knowledge of the relationship between m6A modification and inflammation in human diseases remains unclear. In this review, we will discuss the association between m6A modification and inflammatory response in diseases, especially the role, mechanisms, and potential clinical application of m6A as a biomarker and therapeutic target for inflammatory diseases.

Retinal microglia polarization in diabetic retinopathy

Microglia, the main immune cell of the central nervous system (CNS), categorized into M1-like phenotype and M2-like phenotype, play important roles in phagocytosis, cell migration, antigen presentation, and cytokine production. As a part of CNS, retinal microglial cells (RMC) play an important role in retinal diseases. Diabetic retinopathy (DR) is one of the most common complications of diabetes. Recent studies have demonstrated that DR is not only a microvascular disease but also retinal neurodegeneration. RMC was regarded as a central role in neurodegeneration and neuroinflammation. Therefore, in this review, we will discuss RMC polarization and its possible regulatory factors in early DR, which will provide new targets and insights for early intervention of DR.

The Interplay Between Diet and the Epigenome in the Pathogenesis of Type-1 Diabetes

The autoimmune disease, Type 1 Diabetes Mellitus (T1DM), results in the destruction of pancreatic β-cells, and the International Diabetes Federation reports that its incidence is increasing worldwide. T1DM is a complex disease due to the interaction between genetic and environmental factors. Certain dietary patterns and nutrients are known to cause epigenetic modifications in physiological conditions and diseases. However, the interplay between diet and epigenetics is not yet well-understood in the context of T1DM. Several studies have described epigenetic mechanisms involved in the autoimmune reactions that destroy the β-cells, but few explored diet components as potential triggers for epigenetic modifications. Clarifying the link between diet and epigenome can provide new insights into the pathogenesis of T1DM, potentially leading to new diagnostic and therapeutic approaches. In this mini review, we shed light on the influence of the diet-epigenome axis on the pathophysiology of T1DM.

DNA methylation of FTO promotes renal inflammation by enhancing m6A of PPAR-α in alcohol-induced kidney injury

Alcohol consumption is one of the risk factors for kidney injury. The underlying mechanism of alcohol-induced kidney injury remains largely unknown. We previously found that the kidney in a mouse model of alcoholic kidney injury had severe inflammation. In this study, we found that the administration of alcohol was associated with the activation of NLRP3 inflammasomes and NF-κB signaling, and the production of pro-inflammatory cytokines. Whole-genome methylation sequencing (WGBS) showed that the DNA encoding fat mass and obesity-associated protein (FTO) was significantly methylated in the alcoholic kidney. This finding was confirmed with the bisulfite sequencing (BSP), which showed that alcohol increased DNA methylation of FTO in the kidney. Furthermore, inhibition of DNA methyltransferases (DNMTs) by 5-azacytidine (5-aza) reversed alcohol-induced kidney injury and decreased the mRNA and protein levels of FTO. Importantly, we found that FTO, the m6A demethylase, epigenetically modified peroxisome proliferator activated receptor-α (PPAR-α) in a YTH domain family 2 (YTHDF2)-dependent manner, which resulted in inflammation in alcoholic kidney injury models. In conclusion, our findings indicate that alcohol increases the methylation of PPAR-α m6A by FTO-mediated YTHDF2 epigenetic modification, which ultimately leads to the activation of NLRP3 inflammasomes and NF-κB-driven renal inflammation in the kidney. These findings may provide novel strategies for preventing and treating alcoholic kidney diseases.

Long non-coding RNA HCG18 promotes M1 macrophage polarization through regulating the miR-146a/TRAF6 axis, facilitating the progression of diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) is one of the most important complications in diabetes mellitus (DM), which has been reported to be modulated by long non-coding RNAs (lncRNAs). The purpose of the current study is to explore the regulatory mechanism of lncRNA HCG18 on DPN in vitro. The expression of lncRNA HCG18, miR-146a, TRAF6, CD11c, and iNOS was detected by qRT-PCR. Through Enzyme-linked immunosorbent assay, the levels of inflammatory factors (TNF-α, IL-1β, and IL-6) were determined. M1 macrophage polarization was measured by flow cytometry analysis. The interactions between miR-146a and HCG18/TRAF6 were predicted by Starbase/Targetscan software and verified by the dual luciferase reporter assay. Western blot assay was performed to determine the protein expression of TRAF6. LncRNA HCG18 was highly expressed in DPN model and HG-induced macrophages. The levels of inflammatory factors (TNF-α, IL-1β, and IL-6) were elevated in DPN model. The expression of M1 markers (CD11c and iNOS) was visibly up-regulated in DPN model and was positively correlated with HCG18 expression. LncRNA HCG18 facilitated M1 macrophage polarization. In addition, miR-146a was identified as a target of lncRNA HCG18. Overexpression of miR-146a reversed the promoting effect of HCG18 on M1 macrophage polarization. Simultaneously, TRAF6 was a target gene of miR-146a TRAF6 expression was positively modulated by HCG18 and was negatively modulated by miR-146a. Down-regulation of TRAF6 reversed the promoting effect of HCG18 on M1 macrophage polarization. LncRNA HCG18 promotes M1 macrophage polarization via regulating the miR-146a/TRAF6 axis, facilitating the progression of DPN. This study provides a possible therapeutic strategy for DPN.

The critical roles of m6A modification in metabolic abnormality and cardiovascular diseases

N6-methyladenosine (m6A) RNA methylation is an emerging area of epigenetics, which is a reversible and dynamic modification mediating by ‘writers’ (methylase, adding methyl groups, METTL3, METTL14, and WTAP), ‘erasers’ (demethylase, deleting methyl groups, FTO and ALKBH5), and ‘readers’ (YTHDF1-3, YTHDC1 and YTHDC2). Recent studies in human, animal models and cell levels have disclosed a critical role of m6A modification in regulating the homeostasis of metabolic processes and cardiovascular function. Evidence from these studies identify m6A as a candidate of biomarker and therapeutic target for metabolic abnormality and cardiovascular diseases (CVD). Comprehensive understanding of the complexity of m6A regulation in metabolic diseases and CVD will be helpful for us to understand the pathogenesis of CVD. In this review, we discuss the regulatory role of m6A in metabolic abnormality and CVD. We will emphasize the clinical relevance of m6A dysregulation in CVD.

miRNA/Target Gene Profile of Endothelial Cells Treated with Human Triglyceride-Rich Lipoproteins Obtained after a High-Fat Meal with Extra-Virgin Olive Oil or Sunflower Oil

SCOPE

The effects of triglyceride-rich lipoproteins (TRLs) on the miRNA expression of endothelial cells, which are very involved in atherosclerosis, according to the type of diet are not known.

METHODS AND RESULTS

The differences between the effects of TRLs isolated from blood of subjects after a high-fat meal with extra-virgin olive oil (EVOO) and sunflower oil (SO) on the microRNA-Seq profile related to atherosclerosis in human umbilical vein endothelial cells are analyzed. 28 upregulated microRNAs with EVOO-derived TRLs, which can regulate 22 genes related to atherosclerosis, are found. 21 upregulated microRNAs with SO-derived TRLs, which can regulate 20 genes related to atherosclerosis, are found. These microRNAs are mainly involved in angiogenesis, with a predominance of an anti-angiogenic effect with EVOO-derived TRLs. Other microRNAs upregulated with SO-derived TRLs are involved in cardiovascular diseases. Pathways for the target genes obtained from the upregulated microRNA with EVOO-derived TRLs are involved in lipid metabolism and inflammatory and defense response, while those with SO-derived TRLs are involved in lipid metabolic process.

CONCLUSION

EVOO-derived TRLs seem to produce a more atheroprotective profile than SO-derived TRLs. This study provides alternative mechanisms on the protective role of EVOO against the atherogenic process through microRNA regulation in endothelial cells.

N6-Methyladenosine Demethylase FTO Contributes to Neuropathic Pain by Stabilizing G9a Expression in Primary Sensory Neurons

Nerve injury-induced change in gene expression in primary sensory neurons of dorsal root ganglion (DRG) is critical for neuropathic pain genesis. N6-methyladenosine (m6A) modification of RNA represents an additional layer of gene regulation. Here, it is reported that peripheral nerve injury increases the expression of the m6A demethylase fat-mass and obesity-associated proteins (FTO) in the injured DRG via the activation of Runx1, a transcription factor that binds to the Fto gene promoter. Mimicking this increase erases m6A in euchromatic histone lysine methyltransferase 2 (Ehmt2) mRNA (encoding the histone methyltransferase G9a) and elevates the level of G9a in DRG and leads to neuropathic pain symptoms. Conversely, blocking this increase reverses a loss of m6A sites in Ehmt2 mRNA and destabilizes the nerve injury-induced G9a upregulation in the injured DRG and alleviates nerve injury-associated pain hypersensitivities. FTO contributes to neuropathic pain likely through stabilizing nerve injury-induced upregulation of G9a, a neuropathic pain initiator, in primary sensory neurons.