Dicer mediating the expression of miR-143 and miR-155 regulates hexokinase II associated cellular response to hypoxia

Environmental arsenic pollution induced liver oxidative stress injury by regulating miR-155 through inhibition of AUF1

Arsenic (As), a common environmental pollutant, has become a hot topic in recent years due to its potentially harmful effects. Liver damage being a central clinical feature of chronic arsenic poisoning. However, the underlying mechanisms remain unclear. We demonstrated that arsenic can lead to oxidative stress in the liver and result in structural and functional liver damage, significantly correlated with the expression of AUF1, Dicer1, and miR-155 in the liver. Interestingly, knockdown AUF1 promoted the up-regulatory effects of arsenic on Dicer1 and miR-155 and the inhibitory effects on SOD1, which exacerbated oxidative damage in rat liver. However, overexpression of AUF1 reversed the up-regulatory effects of arsenic on Dicer1 and miR-155, restored arsenic-induced SOD1 depletion, and attenuated liver oxidative stress injury. Further, we verified the mechanism and targets of miR-155 in regulating SOD1 by knockdown/overexpression of miR-155 and nonsense mutant SOD1 3'UTR experiments. In conclusion, these results powerfully demonstrate that arsenic inhibits AUF1 protein expression, which in turn reduces the inhibitory effect on Dicer1 expression, which promotes miR-155 to act on the SOD1 3'UTR region after high expression, thus inhibiting SOD1 protein expression and enzyme activity, and inducing liver injury. This finding provides a new perspective for the mechanism research and targeted prevention of arsenic poisoning, as well as scientific evidence for formulating strategies to prevent and control environmental arsenic pollution.

Hypoxia-inducible microRNA-155 negatively regulates epithelial barrier in eosinophilic esophagitis by suppressing tight junction claudin-7

MicroRNA (miRNA)-mediated mRNA regulation directs many homeostatic and pathological processes, but how miRNAs coordinate aberrant esophageal inflammation during eosinophilic esophagitis (EoE) is poorly understood. Here, we report a deregulatory axis where microRNA-155 (miR-155) regulates epithelial barrier dysfunction by selectively constraining tight junction CLDN7 (claudin-7). MiR-155 is elevated in the esophageal epithelium of biopsies from patients with active EoE and in cell culture models. MiR-155 localization using in situ hybridization (ISH) in patient biopsies and intra-epithelial compartmentalization of miR-155 show expression predominantly within the basal epithelia. Epithelial miR-155 activity was evident through diminished target gene expression in 3D organotypic cultures, particularly in relatively undifferentiated basal cell states. Mechanistically, generation of a novel cell line with enhanced epithelial miR-155 stable overexpression induced a functionally deficient epithelial barrier in 3D air-liquid interface epithelial cultures measured by transepithelial electrical resistance (TEER). Histological assessment of 3D esophageal organoid cultures overexpressing miR-155 showed notable dilated intra-epithelial spaces. Unbiased RNA-sequencing analysis and immunofluorescence determined a defect in epithelial barrier tight junctions and revealed a selective reduction in the expression of critical esophageal tight junction molecule, claudin-7. Together, our data reveal a previously unappreciated role for miR-155 in mediating epithelial barrier dysfunction in esophageal inflammation.

Altered MicroRNA Maturation in Ischemic Hearts: Implication of Hypoxia on XPO5 and DICER1 Dysregulation and RedoximiR State

Ischemic cardiomyopathy (ICM) is associated with abnormal microRNA expression levels that involve an altered gene expression profile. However, little is known about the underlying causes of microRNA disruption in ICM and whether microRNA maturation is compromised. Therefore, we focused on microRNA maturation defects analysis and the implication of the microRNA biogenesis pathway and redox-sensitive microRNAs (redoximiRs). Transcriptomic changes were investigated via ncRNA-seq (ICM, n = 22; controls, n = 8) and mRNA-seq (ICM, n = 13; control, n = 10). The effect of hypoxia on the biogenesis of microRNAs was evaluated in the AC16 cell line. ICM patients showed a reduction in microRNA maturation compared to control (4.30 ± 0.94 au vs. 5.34 ± 1.07 au, p ˂ 0.05), accompanied by a deregulation of the microRNA biogenesis pathway: a decrease in pre-microRNA export (XPO5, FC = -1.38, p ˂ 0.05) and cytoplasmic processing (DICER, FC = -1.32, p ˂ 0.01). Both processes were regulated by hypoxia in AC16 cells (XPO5, FC = -1.65; DICER1, FC = -1.55; p ˂ 0.01; Exportin-5, FC = -1.81; Dicer, FC = -1.15; p ˂ 0.05). Patients displayed deregulation of several redoximiRs, highlighting miR-122-5p (FC = -2.41, p ˂ 0.001), which maintained a good correlation with the ejection fraction (r = 0.681, p ˂ 0.01). We evidenced a decrease in microRNA maturation mainly linked to a decrease in XPO5-mediated pre-microRNA export and DICER1-mediated processing, together with a general effect of hypoxia through deregulation of biogenesis pathway and the redoximiRs.

The novel importance of miR-143 in obesity regulation

Obesity and substantially increased risk of metabolic diseases have become a global epidemic. microRNAs have attracted a great deal of attention as a potential therapeutic target for obesity. MiR-143 has been known to specifically promote adipocyte differentiation by downregulating extracellular signal-regulated kinase 5. Our latest study found that miR-143 knockout is against diet-induced obesity by promoting brown adipose tissue thermogenesis and inhibiting white adipose tissue adipogenesis. Moreover, LPS- or IL-6-induced inhibition of miR-143 expression in brown adipocytes promotes thermogenesis by targeting adenylate cyclase 9. In this review, we will summarize the expression and functions of miR-143 in different tissues, the influence of obesity on miR-143 in various tissues, the important role of adipose-derived miR-143 in the development of obesity, the role of miR-143 in immune cells and thermoregulation and discuss the potential significance and application prospects of miR-143 in obesity management.

MicroRNAs as Regulators of Cancer Cell Energy Metabolism

To adapt to the tumor environment or to escape chemotherapy, cancer cells rapidly reprogram their metabolism. The hallmark biochemical phenotype of cancer cells is the shift in metabolic reprogramming towards aerobic glycolysis. It was thought that this metabolic shift to glycolysis alone was sufficient for cancer cells to meet their heightened energy and metabolic demands for proliferation and survival. Recent studies, however, show that cancer cells rely on glutamine, lipid, and mitochondrial metabolism for energy. Oncogenes and scavenging pathways control many of these metabolic changes, and several metabolic and tumorigenic pathways are post-transcriptionally regulated by microRNA (miRNAs). Genes that are directly or indirectly responsible for energy production in cells are either negatively or positively regulated by miRNAs. Therefore, some miRNAs play an oncogenic role by regulating the metabolic shift that occurs in cancer cells. Additionally, miRNAs can regulate mitochondrial calcium stores and energy metabolism, thus promoting cancer cell survival, cell growth, and metastasis. In the electron transport chain (ETC), miRNAs enhance the activity of apoptosis-inducing factor (AIF) and cytochrome c, and these apoptosome proteins are directed towards the ETC rather than to the apoptotic pathway. This review will highlight how miRNAs regulate the enzymes, signaling pathways, and transcription factors of cancer cell metabolism and mitochondrial calcium import/export pathways. The review will also focus on the metabolic reprogramming of cancer cells to promote survival, proliferation, growth, and metastasis with an emphasis on the therapeutic potential of miRNAs for cancer treatment.

miR-143-Mediated Responses to Betaine Supplement Repress Lipogenesis and Hepatic Gluconeogenesis by Targeting MAT1a and MAPK11

The liver as the central organ is responsible for lipogenesis, gluconeogenesis and one-carbon metabolism. Methyl donors (e.g., betaine) modulate metabolic homeostasis and gene regulation through one-carbon metabolism. MiR-143 regulates DNA methylation by targeting DNMT3A, thereby suggesting that this miRNA participates in one-carbon metabolic pathways. However, the effect and mechanism that regulate glucose and lipid metabolism via the methyl group metabolism pathway remain elusive. In this study, we found that a betaine supplement and miR-143 KO significantly promoted lipolysis and glucose utilization and repressed lipogenesis and gluconeogenesis through enhancing energy consumption and thermogenesis, repressing GPNMB and targeting MAPK11, respectively. We further explored the relationship between miR-143 and a methyl donor (betaine) and the miR-143-mediated responses to the betaine supplement regulating the mechanism of the glucose and lipid metabolism. The results showed that betaine significantly down-regulated the expression of miR-143 that subsequently increased SAM levels in the liver by targeting MAT1a. In brief, the regulations of glucose and lipid metabolism are related to the miR-143-regulation of one-carbon units, and the relationship between betaine and miR-143 in the methionine cycle is a typical yin-yang type of regulation. Thus, betaine and miR-143 function together as key regulators and biomarkers for preventing and diagnosing metabolic diseases such as fatty liver disease, obesity, and diabetes.

Follicular fluid-derived exosomal miR-143-3p/miR-155-5p regulate follicular dysplasia by modulating glycolysis in granulosa cells in polycystic ovary syndrome

Objective

Polycystic ovary syndrome (PCOS) is characterized by follicular dysplasia. An insufficient glycolysis-derived energy supply of granulosa cells (GCs) is an important cause of follicular dysplasia in PCOS. Follicular fluid (FF) exosomal microRNAs (miRNAs) have been proven to regulate the function of GCs. In this study, exosomes extracted from clinical FF samples were used for transcriptome sequencing (RNA-seq) analysis, and a human ovarian granulocyte tumour cell line (KGN cells) was used for in vitro mechanistic studies.

Methods and results

In FF exosomal RNA-seq analysis, a decrease in glycolysis-related pathways was identified as an important feature of the PCOS group, and the differentially expressed miR-143-3p and miR-155-5p may be regulatory factors of glycolysis. By determining the effects of miR-143-3p and miR-155-5p on hexokinase (HK) 2, pyruvate kinase muscle isozyme M2 (PKM2), lactate dehydrogenase A (LDHA), pyruvate, lactate and apoptosis in KGN cells, we found that upregulated miR-143-3p expression in exosomes from the PCOS group inhibited glycolysis in KGN cells; knockdown of miR-143-3p significantly alleviated the decrease in glycolysis in KGN cells in PCOS. MiR-155-5p silencing attenuated glycolytic activation in KGN cells; overexpression of miR-155-5p significantly promoted glycolysis in KGN cells in PCOS. In this study, HK2 was found to be the mediator of miR-143-3p and miR-155-5p in FF-derived exosome-mediated regulation of glycolysis in KGN cells. Reduced glycolysis accelerated apoptosis of KGN cells, which mediated follicular dysplasia through ATP, lactate and apoptotic pathways.

Conclusions

In conclusion, these results indicate that miR-143-3p and miR-155-5p in FF-derived exosomes antagonistically regulate glycolytic-mediated follicular dysplasia of GCs in PCOS.

Association Between miR-143/145 rs4705343 Polymorphism and Risk of Congenital Heart Disease in a Chinese Tibetan Population

Objective: Congenital heart disease (CHD) is the most common birth defect worldwide and is caused by both genetic and environmental factors. The microRNA (miR)-143/145 cluster is involved in various biological processes related to cardiovascular development. The functional single nucleotide polymorphism (SNP) rs4705343 of miR-143/145 may influence the expression of these miRNAs. In this study, we aimed to estimate the association between miR-143/145 rs4705343 and the risk of CHD in a Chinese Tibetan population. Methods: Matrix-assisted laser desorption ionization time-of-flight mass spectrometry assays were performed to genotype the miRNA-143/145 rs4705343 SNP in 510 CHD Tibetan patients and 681 unrelated Tibetan healthy controls. The associations between the SNP frequencies and the CHD risk were analyzed by χ² test/Fisher's test and assessed by odds ratios (ORs) and 95% confidence intervals (95% CIs). Results: We successfully genotyped 1165 subjects with a SNP call rate of 97.8%. Under the allelic model we found that rs4705343 was not associated with the risk of CHD (p = 0.082), but under the recessive model the CC genotype at this locus was associated with a significantly increased risk of CHD compared with the other genotypes (CC vs TT+TC: OR = 1.60, 95% CI = 1.08-2.37, p = 0.017). Conclusion: The present study suggests that the rs4705343 CC genotype of miR-143/145 is associated with CHD risk in a Chinese Tibetan population.

Hypoxia-mediated down-regulation of miRNAs' biogenesis promotes tumor immune escape in bladder cancer

BACKGROUND

The study examines the function of hypoxia-mediated down-regulation of microRNAs (miRNAs) (mir-30c, mir-135a, and mir-27a) in the process of bladder cancer immune escape.

METHODS

Quantitative Real-time PCR (qRT-PCR) was carried out to determine gene expression levels of Drosha and Dicer under hypoxia treatment, while western blotting and flow cytometry were used to determine protein expression. Seven reported miRNAs were identified via qRT-PCR assay. Flow cytometry detection of CD3/CD4/CD8-positive expression and statistics. Enzyme-linked immunosorbent assay (ELISA) detected cellular immune factors content. Cell apoptosis was checked via flow cytometry assay. Luciferase report assay and western blot assays were both used to verify the relationship between miRNAs and Casitas B-lineage lymphoma proto-oncogene b (Cbl-b). The animal model was established and Hematoxylin-eosin (HE) staining, TdT-mediated dUTP Nick-End Labeling (TUNEL) staining, and immunohistochemistry (IHC) assays were separately used to verify the conclusions.

RESULTS

The CD3 + /CD4 + expression was increased in the hypoxia group, while CD3 + /CD8 + expression, the cellular immune factors content Interleukin-2 (IL-2) and Tumor Necrosis Factor-α (TNFα) along with the cell apoptosis were suppressed. The protein expression of Cbl-b was found to be up-regulated in the hypoxia group. After constructing the overexpression/ knockdown of Cbl-b in peripheral blood mononuclear cell (PBMC), Cbl-b has been found to promote tumor immune escape in bladder cancer. Furthermore, Cbl-b had been identified as the co-targets of mir-30c, mir-135a, and mir-27a and down-regulation of miRNA biogenesis promotes Cbl-b expression and deactivating T cells in vitro/in vivo.

CONCLUSION

Hypoxia-mediated down-regulation of miRNAs' biogenesis promotes tumor immune escape in bladder cancer, which could bring much more advance to the medical research on tumors.

Neutralization of hexokinase 2-targeting miRNA attenuates the oxidative stress-induced cardiomyocyte apoptosis

Hexokinase 2 (HK2) is a metabolic sensor that couples glycolysis and oxidative phosphorylation of mitochondria by binding to the outer mitochondrial membrane (OMM), and it also has been implicated in induction of apoptotic process by regulating the integrity of OMM. When HK2 detaches from the mitochondria, it triggers permeability increase of the OMM and subsequently facilitates the cytosolic release of cytochrome c, a major apoptosis-inducing factor. According to previous studies, a harsh microenvironment created by ischemic heart disease such as low tissue oxygen and nutrients, and increased reactive oxygen species (ROS) can cause cardiomyocyte apoptosis. Under these conditions, the expression of HK2 in heart significantly decrease and such down-regulation of HK2 was correlated to the increased apoptosis of cardiomyocytes. Therefore, prevention of HK2 down-regulation may salvage cardiomyocytes from apoptosis. MicroRNAs are short, non-coding RNAs that either inhibit transcription of target mRNAs or degrade the targeted mRNAs via complementary binding to the 3'UTR (untranslated region) of the targeted mRNAs. Since miRNAs are known to be involved in virtually every biological processes, it is reasonable to assume that the expression of HK2 is also regulated by miRNAs. Currently, to my best knowledge, there is no previous study examined the miRNA-mediated regulation of HK2 in cardiomyocytes. Thus, in the present study, miRNA-mediated modulation of HK2 during ROS (H2O2)-induced cardiomyocyte apoptosis was investigated. First, the expression of HK2 in cardiomyocytes exposed to H2O2 was evaluated. H2O2 (500 μM) induced cardiomyocyte apoptosis and it also decreased the mitochondrial expression of HK2. Based on miRNA-target prediction databases and empirical data, miR-181a was identified as a HK2-targeting miRNA. To further examine the effect of negative regulation of the selected HK2-targeting miRNA on cardiomyocyte apoptosis, anti-miR-181a, which neutralizes endogenous miR-181a, was utilized. Delivery of anti-miR-181a significantly abrogated the H2O2-induced suppression of HK2 expression and subsequent disruption of mitochondrial membrane potential, improving the survival of cardiomyocytes exposed to H2O2. These findings suggest that miR-181a-mediated down-regulation of HK2 contributes to the apoptosis of cardiomyocytes exposed to ROS. Neutralizing miR-181a can be a viable and effective means to prevent cardiomyocyte from apoptosis in ischemic heart disease.

Role and mechanisms of autophagy in lung metabolism and repair

Mammalian lungs are metabolically active organs that frequently encounter environmental insults. Stress responses elicit protective autophagy in epithelial barrier cells and the supportive niche. Autophagy promotes the recycling of damaged intracellular organelles, denatured proteins, and other biological macromolecules for reuse as components required for lung cell survival. Autophagy, usually induced by metabolic defects, regulates cellular metabolism. Autophagy is a major adaptive response that protects cells and organisms from injury. Endogenous region-specific stem/progenitor cell populations are found in lung tissue, which are responsible for epithelial repair after lung damage. Additionally, glucose and fatty acid metabolism is altered in lung stem/progenitor cells in response to injury-related lung fibrosis. Autophagy deregulation has been observed to be involved in the development and progression of other respiratory diseases. This review explores the role and mechanisms of autophagy in regulating lung metabolism and epithelial repair.

MicroRNA-mediated stress response in bivalve species

Bivalve mollusks are important aquatic organisms, which are used for biological monitoring because of their abundance, ubiquitous nature, and abilities to adapt to different environments. MicroRNAs (miRNAs) are small noncoding RNAs, which typically silence the expression of target genes; however, certain miRNAs directly or indirectly upregulate their target genes. They are rapidly modulated and play an essential role in shaping the response of organisms to stresses. Based on the regulatory function and rapid alteration of miRNAs, they could act as biomarkers for biotic and abiotic stress, including environmental stresses and contaminations. Moreover, mollusk, particularly hemocytes, rapidly respond to environmental changes, such as pollution, salinity changes, and desiccation, which makes them an attractive model for this purpose. Thus, bivalve mollusks could be considered a good animal model to examine a system's response to different environmental conditions and stressors. miRNAs have been reported to adjust the adaptation and physiological functions of bivalves during endogenous and environmental stressors. In this review, we aimed to discuss the potential mechanisms underlying the response of bivalves to stressors and how miRNAs orchestrate this process; however, if necessary, other organisms' response is included to explain specific processes.

MicroRNAs in the regulation of cellular redox status and its implications in myocardial ischemia-reperfusion injury

MicroRNAs (miRNAs) are small RNAs that do not encode for proteins and play key roles in the regulation of gene expression. miRNAs are involved in a comprehensive range of biological processes such as cell cycle control, apoptosis, and several developmental and physiological processes. Oxidative stress can affect the expression levels of multiple miRNAs and, conversely, miRNAs may regulate the expression of redox sensors, alter critical components of the cellular antioxidants, interact with the proteasome, and affect DNA repair systems. The number of publications identifying redox-sensitive miRNAs has increased significantly over the last few years, and some miRNA targets such as Nrf2, SIRT1 and NF-κB have been identified. The complex interplay between miRNAs and ROS is discussed together with their role in myocardial ischemia-reperfusion injury and the potential use of circulating miRNAs as biomarkers of myocardial infarction. Detailed knowledge of redox-sensitive miRNAs is needed to be able to effectively use individual compounds or sets of miRNA-modulating compounds to improve the health-related outcomes associated with different diseases.

Micromanaging aerobic respiration and glycolysis in cancer cells

BACKGROUND

Cancer cells possess a common metabolic phenotype, rewiring their metabolic pathways from mitochondrial oxidative phosphorylation to aerobic glycolysis and anabolic circuits, to support the energetic and biosynthetic requirements of continuous proliferation and migration. While, over the past decade, molecular and cellular studies have clearly highlighted the association of oncogenes and tumor suppressors with cancer-associated glycolysis, more recent attention has focused on the role of microRNAs (miRNAs) in mediating this metabolic shift. Accumulating studies have connected aberrant expression of miRNAs with direct and indirect regulation of aerobic glycolysis and associated pathways.

SCOPE OF REVIEW

This review discusses the underlying mechanisms of metabolic reprogramming in cancer cells and provides arguments that the earlier paradigm of cancer glycolysis needs to be updated to a broader concept, which involves interconnecting biological pathways that include miRNA-mediated regulation of metabolism. For these reasons and in light of recent knowledge, we illustrate the relationships between metabolic pathways in cancer cells. We further summarize our current understanding of the interplay between miRNAs and these metabolic pathways. This review aims to highlight important metabolism-associated molecular components in the hunt for selective preventive and therapeutic treatments.

MAJOR CONCLUSIONS

Metabolism in cancer cells is influenced by driver mutations but is also regulated by posttranscriptional gene silencing. Understanding the nuanced regulation of gene expression in these cells and distinguishing rapid cellular responses from chronic adaptive mechanisms provides a basis for rational drug design and novel therapeutic strategies.

Potential contribution of erythrocyte microRNA to secondary erythrocytosis and thrombocytopenia in congenital heart disease

BackgroundChildren with cyanotic heart disease develop secondary erythrocytosis and thrombocytopenia via unknown mechanisms. Mature erythrocyte microRNAs may reflect clinical pathologies and cell differentiation processes pre-enucleation. This study evaluated erythrocyte microRNAs in children with cyanotic heart disease.MethodsErythrocyte microRNAs from children with cyanotic and acyanotic heart disease and without cardiac disease were quantified with Ion PGM System (n=10 per group). Differential expression was confirmed by quantitative PCR (qPCR; n=20 per group).ResultsMir-486-3p, mir-486-5p, and mir-155-5p increased in patients with cyanotic heart disease compared with those without heart disease: fold differences (95% confidence interval): mir-486-3p: 1.92 (1.14-3.23), P=0.011; mir-486-5p: 2.27 (1.41-3.65), P<0.001; and mir-155-5p: 1.44 (1.03-2.03), P=0.028. Mir-486-5p was increased, and let-7e-5p and mir-1260a were decreased in patients with acyanotic heart disease compared with those without heart disease: mir-486-5p: 1.66 (1.03-2.66), P=0.035; let-7e-5p: 0.66 (0.44-0.99), P=0.049; and mir-1260a: 0.53 (0.29-0.99), P=0.045.ConclusionSeveral microRNA levels changed in children with cyanotic and acyanotic heart disease. Mir-486-3p and -5p are associated with hematopoietic differentiation. Mir-486-3p regulates the erythroid vs. megakaryocyte lineage fate decision. Mir-155 is a hypoxia-inducible microRNA, whose overexpression inhibits megakaryocyte differentiation. Erythrocyte microRNA expression changes may contribute to erythrocytosis and thrombocytopenia in children with cyanotic heart disease.

Cyclin-dependent kinase 5 regulates MAPK/ERK signaling in the skin of mice

Cyclin-dependent kinase 5 (CDK5) is a proline-directed serine/threonine kinase that has been shown to play important roles in many tissues except the nervous system. We previously reported that CDK5 showed differential expression in the transcriptome profiles of the skin of alpacas with different hair colors. To understand the functional role of CDK5 in hair color determination, we constructed CDK5-knockdown mice and identified the effect on the mitogen-activated protein kinase (MAPK) pathway in the mouse skin. Quantitative real-time polymerase chain reaction, co-immunoprecipitation, and western blotting were performed to analyze the effects of CDK5-knockdown on the MAPK pathway in mice. The results showed that MAP3K6 was inhibited by phosphorylated CDK5 through its activator CDK7. The decrease in MAP3K6 levels caused down-regulation of MEK1 and ERK expression, leading to the up-regulation of miR-143-3p, which targets MAP3K6 via Dicer. Taken together, our findings indicate that CDK5 functions in regulating the MAPK pathway. Given that MAP3K6 was inhibited in two directions, this mechanism can provide insight into the contributions of the MAPK/ERK pathway to the inhibition of melanin production.

Role of multifaceted regulators in cancer glucose metabolism and their clinical significance

Aberrant glucose metabolism, "aerobic glycolysis" or "Warburg effect", is a hallmark of human cancers. There is a cluster of "multifaceted regulators", which plays a pivotal role in the regulation of glucose metabolism. They can not only modulate the activities of specific enzymes, but also act as transcriptional activators to regulate the expression of metabolism related genes. Additionally, they can crosstalk with other key factors involved in glucose metabolism and work together to initiate multiple oncogenic processes. These "multifaceted regulators", especially p53, HIF-1, TIGAR and microRNA, will be focused in this review. And we will comprehensively illustrate their regulatory effects on cancer glucose metabolism, and further elaborate on their clinical significance. In-depth elucidation the role of "multifaceted regulators" in cancer glucose metabolism will provide us novel insights in cancer research field and offer promising therapeutic targets for anti-cancer therapies.

Dynamic mRNA and miRNA expression analysis in response to hypoxia and reoxygenation in the blunt snout bream (Megalobrama amblycephala)

Adaptation to hypoxia is a complex process involving various pathways and regulation mechanisms. A better understanding of the genetic influence on these mechanisms could permit selection for hypoxia-sensitive fish. To aid this understanding, an integrated analysis of miRNA and mRNA expression was performed in Megalobrama amblycephala under four acute hypoxia and reoxygenation stages. A number of significantly differentially-expressed miRNAs and genes associated with oxidative stress were identified, and their functional characteristics were revealed by GO function and KEGG pathway analysis. They were found to be involved in HIF-1 pathways known to affect energy metabolism and apoptosis. MiRNA-mRNA interaction pairs were detected from comparison of expression between the four different stages. The function annotation results also showed that many miRNA-mRNA interaction pairs were likely to be involved in regulating hypoxia stress. As a unique resource for gene expression and regulation during hypoxia and reoxygenation, this study could provide a starting point for further studies to better understand the genetic background of hypoxia stress.

Emerging concepts in smooth muscle contributions to airway structure and function: implications for health and disease

Airway structure and function are key aspects of normal lung development, growth, and aging, as well as of lung responses to the environment and the pathophysiology of important diseases such as asthma, chronic obstructive pulmonary disease, and fibrosis. In this regard, the contributions of airway smooth muscle (ASM) are both functional, in the context of airway contractility and relaxation, as well as synthetic, involving production and modulation of extracellular components, modulation of the local immune environment, cellular contribution to airway structure, and, finally, interactions with other airway cell types such as epithelium, fibroblasts, and nerves. These ASM contributions are now found to be critical in airway hyperresponsiveness and remodeling that occur in lung diseases. This review emphasizes established and recent discoveries that underline the central role of ASM and sets the stage for future research toward understanding how ASM plays a central role by being both upstream and downstream in the many interactive processes that determine airway structure and function in health and disease.

(18)F-FDG PET/CT for Monitoring the Response of Breast Cancer to miR-143-Based Therapeutics by Targeting Tumor Glycolysis

Increased glucose utilization is a hallmark of cancer, and tumor metabolism is emerging as anticancer target for therapeutic intervention. Triple-negative breast cancers TNBC are highly glycolytic and show poor clinical outcomes. We previously identified hexokinase 2, the major glycolytic enzyme, as a target gene of miR-143 in TNBC. Here, we developed a therapeutic formulation using cholesterol-modified miR-143 agomir encapsulated in a neutral lipid-based delivery agent that blocked tumor growth and glucose metabolism in TNBC tumor-bearing mice when administered systemically. The antioncogenic effects were accompanied by a reduction in the direct target hexokinase 2 and [¹⁸F]-fluorodeoxyglucose (¹⁸F-FDG) uptake based on positron emission tomography/computed tomography. Treatment with miR-143 formulation has minimal toxic effects and mice tolerated it well. Thus, we demonstrated that miR-143 is a robust inhibitor of the Warburg effect and an effective therapeutic target for TNBC. In addition, ¹⁸F-FDG positron emission tomography/computed tomography can be used to specifically monitor the response of TNBC to miR-143-based therapeutics by targeting tumor glycolysis.

Iron Deprivation Induces Transcriptional Regulation of Mitochondrial Biogenesis

Mitochondria are essential organelles that adapt to stress and environmental changes. Among the nutrient signals that affect mitochondrial form and function is iron, whose depletion initiates a rapid and reversible decrease in mitochondrial biogenesis through unclear means. Here we demonstrate that, unlike the canonical iron-induced alterations to transcript stability, loss of iron dampens the transcription of genes encoding mitochondrial proteins with no change to transcript half-life. Using mass spectrometry, we demonstrate that these transcriptional changes are accompanied by dynamic alterations to histone acetylation and methylation levels that are largely reversible upon readministration of iron. Moreover, histone deacetylase inhibition abrogates the decreased histone acetylation observed upon iron deprivation and restores normal transcript levels at genes encoding mitochondrial proteins. Collectively, we demonstrate that deprivation of an essential nutrient induces transcriptional repression of organellar biogenesis involving epigenetic alterations.

Identification of β-Dystrobrevin as a Direct Target of miR-143: Involvement in Early Stages of Neural Differentiation

Duchenne Muscular Dystrophy, a genetic disorder that results in a gradual breakdown of muscle, is associated to mild to severe cognitive impairment in about one-third of dystrophic patients. The brain dysfunction is independent of the muscular pathology, occurs early, and is most likely due to defects in the assembly of the Dystrophin-associated Protein Complex (DPC) during embryogenesis. We have recently described the interaction of the DPC component β-dystrobrevin with members of complexes that regulate chromatin dynamics, and suggested that β-dystrobrevin may play a role in the initiation of neuronal differentiation. Since oxygen concentrations and miRNAs appear as well to be involved in the cellular processes related to neuronal development, we have studied how these factors act on β-dystrobrevin and investigated the possibility of their functional interplay using the NTera-2 cell line, a well-established model for studying neurogenesis. We followed the pattern of expression and regulation of β-dystrobrevin during the early stages of neuronal differentiation induced by exposure to retinoic acid (RA) under hypoxia as compared with normoxia, and found that β-dystrobrevin expression is regulated during RA-induced differentiation of NTera-2 cells. We also found that β-dystrobrevin pattern is delayed under hypoxic conditions, together with a delay in the differentiation and an increase in the proliferation rate of cells. We identified miRNA-143 as a direct regulator of β-dystrobrevin expression, demonstrated that β-dystrobrevin is expressed in the nucleus and showed that, in line with our previous in vitro results, β-dystrobrevin is a repressor of synapsin I in live cells. Altogether the newly identified regulatory pathway miR-143/β-dystrobrevin/synapsin I provides novel insights into the functions of β-dystrobrevin and opens up new perspectives for elucidating the molecular mechanisms underlying the neuronal involvement in muscular dystrophy.

Integrated analysis of mRNA-seq and miRNA-seq in the liver of Pelteobagrus vachelli in response to hypoxia

Pelteobagrus vachelli is a well-known commercial species in Asia. However, a sudden lack of oxygen will result in mortality and eventually to pond turnover. Studying the molecular mechanisms of hypoxia adaptation in fishes will not only help us to understand fish speciation and the evolution of the hypoxia-signaling pathway, but will also guide us in the breeding of hypoxia-tolerant fish strains. Despite this, the genetic regulatory network for miRNA-mRNA and the signaling pathways involved in hypoxia responses in fish have remained unexamined. In the present study, we used next-generation sequencing technology to characterise mRNA-seq and miRNA-seq of control- and hypoxia-treated P. vachelli livers to elucidate the molecular mechanisms of hypoxia adaptation. We were able to find miRNA-mRNA pairs using bioinformatics analysis and miRNA prediction algorithms. Furthermore, we compared several key pathways which were identified as involved in the hypoxia response of P. vachelli. Our study is the first report on integrated analysis of mRNA-seq and miRNA-seq in fishes and offers a deeper insight into the molecular mechanisms of hypoxia adaptation. qRT-PCR analysis further confirmed the results of mRNA-Seq and miRNA-Seq analysis. We provide a good case study for analyzing mRNA/miRNA expression and profiling a non-model fish species using next-generation sequencing technology.

The tumour hypoxia induced non-coding transcriptome

Recent investigations have highlighted the importance of the non-coding genome in regions of hypoxia in tumours. Such regions are frequently found in solid tumours, and are associated with worse patient survival and therapy resistance. Hypoxia stabilises the transcription factors, hypoxia inducible factors (HIF1α and HIF2α) which coordinate transcriptomic changes that occur in hypoxia. The changes in gene expression induced by HIF1α and HIF2α contribute to many of the hallmarks of cancer phenotypes and enable tumour growth, survival and invasion in the hypoxic tumour microenvironment. Non-coding RNAs, in particular microRNAs (miRNAs), which regulate mRNA stability and translation, and long-non-coding RNAs (lncRNAs), which have diverse functions including chromatin modification and transcriptional regulation, are also important in enabling the key hypoxia regulated processes. They have roles in the regulation of metabolism, angiogenesis, autophagy, invasion and metastasis in the hypoxic microenvironment. Furthermore, HIF1α and HIF2α expression and stabilisation are also regulated by both miRNAs and lncRNAs. Here we review the recent developments in the expression, regulation and functions of miRNAs, lncRNAs and other non-coding RNA classes in tumour hypoxia.

Antioxidant responses and cellular adjustments to oxidative stress

Redox biological reactions are now accepted to bear the Janus faceted feature of promoting both physiological signaling responses and pathophysiological cues. Endogenous antioxidant molecules participate in both scenarios. This review focuses on the role of crucial cellular nucleophiles, such as glutathione, and their capacity to interact with oxidants and to establish networks with other critical enzymes such as peroxiredoxins. We discuss the importance of the Nrf2-Keap1 pathway as an example of a transcriptional antioxidant response and we summarize transcriptional routes related to redox activation. As examples of pathophysiological cellular and tissular settings where antioxidant responses are major players we highlight endoplasmic reticulum stress and ischemia reperfusion. Topologically confined redox-mediated post-translational modifications of thiols are considered important molecular mechanisms mediating many antioxidant responses, whereas redox-sensitive microRNAs have emerged as key players in the posttranscriptional regulation of redox-mediated gene expression. Understanding such mechanisms may provide the basis for antioxidant-based therapeutic interventions in redox-related diseases.

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Antioxidant responses are crucial for both redox signaling and redox damage.

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Glutathione-mediated reactions and Nrf2-Keap1 pathway are key antioxidant responses.

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Redox-related post-translational modifications activate specific signaling pathways.

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Redox-sensitive microRNAs contribute to redox-mediated gene expression regulation.

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ER stress and ischemia-reperfusion are antioxidant-related pathophysiological events.