Role of microRNA-214-targeting phosphatase and tensin homolog in advanced glycation end product-induced apoptosis delay in monocytes

The Role of miRNA in Renal Fibrosis Leading to Chronic Kidney Disease

Chronic kidney disease (CKD) is an important health concern that is expected to be the fifth most widespread cause of death worldwide by 2040. The presence of chronic inflammation, oxidative stress, ischemia, etc., stimulates the development and progression of CKD. Tubulointerstitial fibrosis is a common pathomechanism of renal dysfunction, irrespective of the primary origin of renal injury. With time, fibrosis leads to end-stage renal disease (ESRD). Many studies have demonstrated that microRNAs (miRNAs, miRs) are involved in the onset and development of fibrosis and CKD. miRNAs are vital regulators of some pathophysiological processes; therefore, their utility as therapeutic agents in various diseases has been suggested. Several miRNAs were demonstrated to participate in the development and progression of kidney disease. Since renal fibrosis is an important problem in chronic kidney disease, many scientists have focused on the determination of miRNAs associated with kidney fibrosis. In this review, we present the role of several miRNAs in renal fibrosis and the potential pathways involved. However, as well as those mentioned above, other miRs have also been suggested to play a role in this process in CKD. The reports concerning the impact of some miRNAs on fibrosis are conflicting, probably because the expression and regulation of miRNAs occur in a tissue- and even cell-dependent manner. Moreover, different assessment modes and populations have been used. There is a need for large studies and clinical trials to confirm the role of miRs in a clinical setting. miRNAs have great potential; thus, their analysis may improve diagnostic and therapeutic strategies.

miR-214-Enriched Extracellular Vesicles Released by Acid-Adapted Melanoma Cells Promote Inflammatory Macrophage-Dependent Tumor Trans-Endothelial Migration

Simple Summary

Cutaneous melanoma is the most aggressive form of skin cancer with high-metastatic ability. Despite the recent advancements in melanoma treatments, the prognosis of metastatic patients remains very poor. A better understanding of the molecular mechanisms leading to melanoma dissemination is urgently needed in order to develop novel therapeutical strategies to ameliorate patients’ outcomes. Extracellular vesicles (EV) released by tumor cells are key players in metastasis development: by conveying bioactive molecules with oncogenic activity, they can modulate the surrounding—and even the distant—microenvironment and reprogram recipient cells to facilitate the metastatic cascade. Here, we show that melanoma cells release a higher amount of miR-214-enriched EV when adapted to extracellular acidosis, which promote a macrophage activation state, capable of facilitating the trans-endothelial migration of melanoma cells. Thus, we disclose a new molecular mechanism to prevent melanoma intravasation based on miR-214 targeting.

Abstract

The understanding of the molecular mechanisms leading to melanoma dissemination is urgently needed in view of the identification of new targets and the development of innovative strategies to improve patients’ outcomes. Within the complexity of tumor intercellular communications leading to metastatic dissemination, extracellular vesicles (EV) released by tumor cells are central players. Indeed, the ability to travel through the circulatory system conveying oncogenic bioactive molecules even at distant sites makes EV capable of modulating recipient cells to facilitate metastatic dissemination. The dynamic remodeling of the tumor microenvironment might influence, along with a number of other events, tumoral EV release. We observed that, in melanoma, extracellular acidosis increases the release of EV enriched in miR-214, an onco-miRNA involved in melanoma metastasis. Then, miR-214-enriched EV were found to induce a state of macrophage activation, leading to an overproduction of proinflammatory cytokines and nitric oxide. Such an inflammatory microenvironment was able to alter the endothelial cell permeability, thereby facilitating the trans-endothelial migration of melanoma cells, a crucial step in the metastatic cascade. The use of synthetic miR-214 inhibitors and miR-214 overexpression allowed us to demonstrate the key role of miR-214 in the EV-dependent induction of macrophage activation. Overall, our in vitro study reveals that the release of tumor miR-214-enriched EV, potentiated by adapting tumor cells to extracellular acidosis, drives a macrophage-dependent trans-endothelial migration of melanoma cells. This finding points to miR-214 as a potential new therapeutic target to prevent melanoma intravasation.

Targeting epigenetic regulators for treating diabetic nephropathy

Diabetes is accompanied by the worsening of kidney functions. The reasons for kidney dysfunction mainly include high blood pressure (BP), high blood sugar levels, and genetic makeup. Vascular complications are the leading cause of the end-stage renal disorder (ESRD) and death of diabetic patients. Epigenetics has emerged as a new area to explain the inheritance of non-mendelian conditions like diabetic kidney diseases. Aberrant post-translational histone modifications (PTHMs), DNA methylation (DNAme), and miRNA constitute major epigenetic mechanisms that progress diabetic nephropathy (DN). Increased blood sugar levels alter PTHMs, DNAme, and miRNA in kidney cells results in aberrant gene expression that causes fibrosis, accumulation of extracellular matrix (ECM), increase in reactive oxygen species (ROS), and renal injuries. Histone acetylation (HAc) and histone deacetylation (HDAC) are the most studied epigenetic modifications with implications in the occurrence of kidney disorders. miRNAs induced by hyperglycemia in renal cells are also responsible for ECM accumulation and dysfunction of the glomerulus. In this review, we highlight the role of epigenetic modifications in DN progression and current strategies employed to ameliorate DN.

THP-1 cell line model for tuberculosis: A platform for in vitro macrophage manipulation

Macrophages are large mononuclear phagocytic cells that play a vital role in the immune response. They are present in all body tissues with extremely heterogeneous and plastic phenotypes that adapt to the organs and tissues in which they live and respond in the first-line against invading microorganisms. Tuberculosis (TB) is caused by the pathogenic bacteria Mycobacterium tuberculosis (Mtb), which is among the top 10 global infectious agents and the leading cause of mortality, ranking above human immunodeficiency virus (HIV), as a single infectious agent. Macrophages, upon Mtb infection, not only phagocytose the bacteria and present the antigens to T-cells, but also react rapidly by developing antimycobacterial immune response depending highly on the production of cytokines. However, Mtb is also capable of intracellular survival in instances of sub-optimal activation of macrophages. Hence, several systems have been established to evaluate the Mtb-macrophage interaction, where the THP-1 monocytes have been developed as an attractive model for in vitro polarized monocyte-derived macrophages. This model is extensively used for Mtb as well as other intracellular bacterial studies. Herein, we have summarized the updated implications of the THP-1 model for TB-related studies and discussed the pros and cons compared to other cell models of TB.

In Patients with Chronic Kidney Disease Advanced Glycation End-Products Receptors Isoforms (sRAGE and esRAGE) Are Associated with Malnutrition

Background: in patients with chronic kidney disease (CKD), the inflammatory and pro-oxidant milieu may contribute to malnutrition development. In this study, we investigated the relationship between inflammation, advanced glycation end-products (AGEs), and their receptors (RAGEs) with malnutrition in CKD patients. Methods: we evaluated 117 patients. AGEs were quantified by fluorescence intensity using a fluorescence spectrophotometer, soluble RAGEs isoforms, and inflammatory interleukins by ELISA. Malnutrition was assessed by a malnutrition inflammation score. Results: mean age was 80 ± +11 years, eGFR was 25 ± +11 mL/min/1.73 m2 and BMI was 28 ± 5 Kg/m2. Malnourished individuals were older, had lower estimated protein intake (nPCR 0.65 ± 0.2 vs. 0.8 ± 0.2 vs. 0.8 ± 0.3, p = 0.01), higher C reactive protein (CRP 0.6 ± 1 vs. 0.6 ± 0.7 vs. 0.17 ± 0.13, p = 0.02) and tumor necrosis factor α (TNF α 14.7 ± 8.7 vs. 15.6 ± 8 vs. 11.8 ± 5.8, p = 0.029). Malnourished patients had higher sRAGE (2813 ± 1477 vs. 2158 ± 1236 vs. 2314 ± 1115, p = 0.035) and esRAGE (648 [408–1049] vs. 476 [355–680] vs. 545 [380–730] p = 0.033). In the multivariate analysis, only sRAGE maintained its association with malnutrition (p = 0.02) independently of aging and inflammation. Conclusions: in CKD patients, RAGEs isoforms, but not AGEs, are associated with malnutrition, irrespective of systemic inflammation, aging, and renal function.

Integrative Role of Albumin: Evolutionary, Biochemical and Pathophysiological Aspects

Being one of the main proteins in the human body and many animal species, albumin plays a crucial role in the transport of various ions, electrically neutral molecules and in maintaining the colloidal osmotic pressure of the blood. Albumin is able to bind almost all known drugs, many nutraceuticals and toxic substances, determining their pharmaco- and toxicokinetics. However, albumin is not only the passive but also the active participant of the pharmacokinetic and toxicokinetic processes possessing a number of enzymatic activities. Due to the thiol group of Cys34, albumin can serve as a trap for reactive oxygen and nitrogen species, thus participating in redox processes. The interaction of the protein with blood cells, blood vessels, and also with tissue cells outside the vascular bed is of great importance. The interaction of albumin with endothelial glycocalyx and vascular endothelial cells largely determines its integrative role. This review provides information of a historical nature, information on evolutionary changes, inflammatory and antioxidant properties of albumin, on its structural and functional modifications and their significance in the pathogenesis of some diseases.

Serum Albumin in Health and Disease: Esterase, Antioxidant, Transporting and Signaling Properties

Being one of the main proteins in the human body and many animal species, albumin plays a decisive role in the transport of various ions-electrically neutral and charged molecules-and in maintaining the colloidal osmotic pressure of the blood. Albumin is able to bind to almost all known drugs, as well as many nutraceuticals and toxic substances, largely determining their pharmaco- and toxicokinetics. Albumin of humans and respective representatives in cattle and rodents have their own structural features that determine species differences in functional properties. However, albumin is not only passive, but also an active participant of pharmacokinetic and toxicokinetic processes, possessing a number of enzymatic activities. Numerous experiments have shown esterase or pseudoesterase activity of albumin towards a number of endogeneous and exogeneous esters. Due to the free thiol group of Cys34, albumin can serve as a trap for reactive oxygen and nitrogen species, thus participating in redox processes. Glycated albumin makes a significant contribution to the pathogenesis of diabetes and other diseases. The interaction of albumin with blood cells, blood vessels and tissue cells outside the vascular bed is of great importance. Interactions with endothelial glycocalyx and vascular endothelial cells largely determine the integrative role of albumin. This review considers the esterase, antioxidant, transporting and signaling properties of albumin, as well as its structural and functional modifications and their significance in the pathogenesis of certain diseases.

Monocyte and Macrophage miRNA: Potent Biomarker and Target for Host-Directed Therapy for Tuberculosis

The end TB strategy reinforces the essentiality of readily accessible biomarkers for early tuberculosis diagnosis. Exploration of microRNA (miRNA) and pathway analysis opens an avenue for the discovery of possible therapeutic targets. miRNA is a small, non-coding oligonucleotide characterized by the mechanism of gene regulation, transcription, and immunomodulation. Studies on miRNA define their importance as an immune marker for active disease progression and as an immunomodulator for innate mechanisms, such as apoptosis and autophagy. Monocyte research is highly advancing toward TB pathogenesis and biomarker efficiency because of its innate and adaptive response connectivity. The combination of monocytes/macrophages and their relative miRNA expression furnish newer insight on the unresolved mechanism for Mycobacterium survival, exploitation of host defense, latent infection, and disease resistance. This review deals with miRNA from monocytes, their relative expression in different disease stages of TB, multiple gene regulating mechanisms in shaping immunity against tuberculosis, and their functionality as biomarker and host-mediated therapeutics. Future collaborative efforts involving multidisciplinary approach in various ethnic population with multiple factors (age, gender, mycobacterial strain, disease stage, other chronic lung infections, and inflammatory disease criteria) on these short miRNAs from body fluids and cells could predict the valuable miRNA biosignature network as a potent tool for biomarkers and host-directed therapy.

Thymol alleviates AGEs-induced podocyte injury by a pleiotropic effect via NF-κB-mediated by RhoA/ROCK signalling pathway

Advanced glycation end products (AGE) are those of the most powerful pathogenic factors that related to diabetic complications. In our study, we investigated the beneficial effects of thymol on AGE induced cell injury and apoptosis in human podocytes (HPCs) and attempted to clarify its mechanisms. Our results revealed that stimulation with AGE could significantly activate RhoA/NF-κB pathway. Results showed thymol could markedly suppress inflammatory responses, cell apoptosis and disordered cytoskeleton. Also thymol restored the expression of podocin, restrained migration capacity. Western blot analysis indicated that it could restore the expression of RhoA, ROCK and vimentin, nephrin, podocin and p65 and IκBα phosphorylation. Moreover, si-RhoA also suppressed the expression of pro-inflammatory cytokines, ROCK, and vimentin and the phosphorylation of p65 and IκBα. In conclusion, thymol inhibits AGE-induced cell injury in HPCs by suppressing the RhoA-NF-κB pathway and may be apromising therapeutic agent.

Dysbiosis-Related Advanced Glycation Endproducts and Trimethylamine N-Oxide in Chronic Kidney Disease

Chronic kidney disease (CKD) is a public health concern that affects approximately 10% of the global population. CKD is associated with poor outcomes due to high frequencies of comorbidities such as heart failure and cardiovascular disease. Uremic toxins are compounds that are usually filtered and excreted by the kidneys. With the decline of renal function, uremic toxins are accumulated in the systemic circulation and tissues, which hastens the progression of CKD and concomitant comorbidities. Gut microbial dysbiosis, defined as an imbalance of the gut microbial community, is one of the comorbidities of CKD. Meanwhile, gut dysbiosis plays a pathological role in accelerating CKD progression through the production of further uremic toxins in the gastrointestinal tracts. Therefore, the gut-kidney axis has been attracting attention in recent years as a potential therapeutic target for stopping CKD. Trimethylamine N-oxide (TMAO) generated by gut microbiota is linked to the progression of cardiovascular disease and CKD. Also, advanced glycation endproducts (AGEs) not only promote CKD but also cause gut dysbiosis with disruption of the intestinal barrier. This review summarizes the underlying mechanism for how gut microbial dysbiosis promotes kidney injury and highlights the wide-ranging interventions to counter dysbiosis for CKD patients from the view of uremic toxins such as TMAO and AGEs.

MicroRNAs and Oxidative Stress: An Intriguing Crosstalk to Be Exploited in the Management of Type 2 Diabetes

Type 2 diabetes is a chronic disease widespread throughout the world, with significant human, social, and economic costs. Its multifactorial etiology leads to persistent hyperglycemia, impaired carbohydrate and fat metabolism, chronic inflammation, and defects in insulin secretion or insulin action, or both. Emerging evidence reveals that oxidative stress has a critical role in the development of type 2 diabetes. Overproduction of reactive oxygen species can promote an imbalance between the production and neutralization of antioxidant defence systems, thus favoring lipid accumulation, cellular stress, and the activation of cytosolic signaling pathways, and inducing β-cell dysfunction, insulin resistance, and tissue inflammation. Over the last few years, microRNAs (miRNAs) have attracted growing attention as important mediators of diverse aspects of oxidative stress. These small endogenous non-coding RNAs of 19-24 nucleotides act as negative regulators of gene expression, including the modulation of redox signaling pathways. The present review aims to provide an overview of the current knowledge concerning the molecular crosstalk that takes place between oxidative stress and microRNAs in the physiopathology of type 2 diabetes, with a special emphasis on its potential as a therapeutic target.

Epigenetics and Inflammation in Diabetic Nephropathy

Diabetic nephropathy (DN) leads to high morbidity and disability. Inflammation plays a critical role in the pathogenesis of DN, which involves renal cells and immune cells, the microenvironment, as well as extrinsic factors, such as hyperglycemia, chemokines, cytokines, and growth factors. Epigenetic modifications usually regulate gene expression via DNA methylation, histone modification, and non-coding RNAs without altering the DNA sequence. During the past years, numerous studies have been published to reveal the mechanisms of epigenetic modifications that regulate inflammation in DN. This review aimed to summarize the latest evidence on the interplay of epigenetics and inflammation in DN, and highlight the potential targets for treatment and diagnosis of DN.

Circulating miRNAs in bone health and disease

microRNAs have evolved as important regulators of multiple biological pathways essential for bone homeostasis, and microRNA research has furthered our understanding of the mechanisms underlying bone health and disease. This knowledge, together with the finding that active or passive release of microRNAs from cells into the extracellular space enables minimal-invasive detection in biofluids (circulating miRNAs), motivated researchers to explore microRNAs as biomarkers in several pathologic conditions, including bone diseases. Thus, exploratory studies in cohorts representing different types of bone diseases have been performed. In this review, we first summarize important molecular basics of microRNA function and release and provide recommendations for best (pre-)analytical practices and documentation standards for circulating microRNA research required for generating high quality data and ensuring reproducibility of results. Secondly, we review how the genesis of bone-derived circulating microRNAs via release from osteoblasts and osteoclasts could contribute to the communication between these cells. Lastly, we summarize evidence from clinical research studies that have investigated the clinical utility of microRNAs as biomarkers in musculoskeletal disorders. While previous reviews have mainly focused on diagnosis of primary osteoporosis, we have also included studies exploring the utility of circulating microRNAs in monitoring anti-osteoporotic treatment and for diagnosis of other types of bone diseases, such as diabetic osteopathy, bone degradation in inflammatory diseases, and monogenetic bone diseases.

AGE-RAGE synergy influences programmed cell death signaling to promote cancer

Advanced glycation end products (AGEs) are formed as a result of non-enzymatic reaction between the free reducing sugars and proteins, lipids, or nucleic acids. AGEs are predominantly synthesized during chronic hyperglycemic conditions or aging. AGEs interact with their receptor RAGE and activate various sets of genes and proteins of the signal transduction pathway. Accumulation of AGEs and upregulated expression of RAGE is associated with various pathological conditions including diabetes, cardiovascular diseases, neurodegenerative disorders, and cancer. The role of AGE-RAGE signaling has been demonstrated in the progression of various types of cancer and other pathological disorders. The expression of RAGE increases manifold during cancer progression. The activation of AGE-RAGE signaling also perturbs the cellular redox balance and modulates various cell death pathways. The programmed cell death signaling often altered during the progression of malignancies. The cellular reprogramming of AGE-RAGE signaling with cell death machinery during tumorigenesis is interesting to understand the complex signaling mechanism of cancer cells. The present review focus on multiple molecular paradigms relevant to cell death particularly Apoptosis, Autophagy, and Necroptosis that are considerably influenced by the AGE-RAGE signaling in the cancer cells. Furthermore, the review also attempts to shed light on the provenience of AGE-RAGE signaling on oxidative stress and consequences of cell survival mechanism of cancer cells.

The Role of microRNAs in Metabolic Syndrome-Related Oxidative Stress

Oxidative stress (OxS) is the cause and the consequence of metabolic syndrome (MetS), the incidence and economic burden of which is increasing each year. OxS triggers the dysregulation of signaling pathways associated with metabolism and epigenetics, including microRNAs, which are biomarkers of metabolic disorders. In this review, we aimed to summarize the current knowledge regarding the interplay between microRNAs and OxS in MetS and its components. We searched PubMed and Google Scholar to summarize the most relevant studies. Collected data suggested that different sources of OxS (e.g., hyperglycemia, insulin resistance (IR), hyperlipidemia, obesity, proinflammatory cytokines) change the expression of numerous microRNAs in organs involved in the regulation of glucose and lipid metabolism and endothelium. Dysregulated microRNAs either directly or indirectly affect the expression and/or activity of molecules of antioxidative signaling pathways (SIRT1, FOXOs, Keap1/Nrf2) along with effector enzymes (e.g., GPx-1, SOD1/2, HO-1), ROS producers (e.g., NOX4/5), as well as genes of numerous signaling pathways connected with inflammation, insulin sensitivity, and lipid metabolism, thus promoting the progression of metabolic imbalance. MicroRNAs appear to be important epigenetic modifiers in managing the delicate redox balance, mediating either pro- or antioxidant biological impacts. Summarizing, microRNAs may be promising therapeutic targets in ameliorating the repercussions of OxS in MetS.

AGE/RAGE signaling-mediated endoplasmic reticulum stress and future prospects in non-coding RNA therapeutics for diabetic nephropathy

Disturbance of endoplasmic reticulum (ER) homeostasis triggered by the accumulation of unfolded proteins and advanced glycation end-products (AGEs) plays a major role in pathophysiology of diabetic nephropathy. Activation of receptor for AGEs (RAGE) stimulates NADPH oxidase-mediated reactive oxygen species (ROS) production, leading to ER stress, inflammation, glomerular hypertrophy, podocyte injury, and renal fibrosis. A growing body of evidence indicates that non-coding RNAs (ncRNAs) could rescue ER stress and renal inflammation by the epigenetic modification. This review summarizes ncRNA regulation in AGE/RAGE signaling-mediated ER stress, and discusses the opportunities and challenges of ncRNA-loaded extracellular vesicle therapy in diabetic nephropathy.

PDE5 inhibitor sildenafil attenuates cardiac microRNA 214 upregulation and pro-apoptotic signaling after chronic alcohol ingestion in mice

Abusive chronic alcohol consumption can cause metabolic and functional derangements in the heart and is a risk factor for development of non-ischemic cardiomyopathy. microRNA 214 (miR-214) is a molecular sensor of stress signals that negatively impacts cell survival. Considering cardioprotective and microRNA modulatory effects of sildenafil, a phosphodiesterase 5 (PDE5) inhibitor, we investigated the impact of chronic alcohol consumption on cardiac expression of miR-214 and its anti-apoptotic protein target, Bcl-2 and whether sildenafil attenuates such changes. Adult male FVB mice received unlimited access to either normal liquid diet (control), alcohol diet (35% daily calories intake), or alcohol + sildenafil (1 mg/kg/day, p.o.) for 14 weeks (n = 6-7/group). The alcohol-fed groups with or without sildenafil had increased total diet consumption and lower body weight as compared with controls. Echocardiography-assessed left ventricular function was unaltered by 14-week alcohol intake. Alcohol-fed group had 2.6-fold increase in miR-214 and significant decrease in Bcl-2 expression, along with enhanced phosphorylation of ERK1/2 and cleavage of PARP (marker of apoptotic DNA damage) in the heart. Co-ingestion with sildenafil blunted the alcohol-induced increase in miR-214, ERK1/2 phosphorylation, and maintained Bcl-2 and decreased PARP cleavage levels. In conclusion, chronic alcohol consumption triggers miR-214-mediated pro-apoptotic signaling in the heart, which was prevented by co-treatment with sildenafil. Thus, PDE5 inhibition may serve as a novel protective strategy against cardiac apoptosis due to chronic alcohol abuse.

Prospective Advances in Non-coding RNAs Investigation

Non-coding RNAs (ncRNAs) play significant roles in numerous physiological cellular processes and molecular alterations during pathological conditions including heart diseases, cancer, immunological disorders and neurological diseases. This chapter is focusing on the basis of ncRNA relation with their functions and prospective advances in non-coding RNAs particularly miRNAs investigation in the cardiovascular disease management.The field of ncRNAs therapeutics is a very fascinating and challenging too. Scientists have opportunity to develop more advanced therapeutics as well as diagnostic approaches for cardiovascular conditions. Advanced studies are critically needed to deepen the understanding of the molecular biology, mechanism and modulation of ncRNAs and chemical formulations for managing CVDs.

PTEN and PHLPP crosstalk in cancer cells and in TGFβ-activated stem cells

Akt kinase regulates several cellular processes, among them growth, proliferation and survival, and has been correlated to neoplastic disease. We report here crosstalk between several Akt regulatory phosphatases that controls the level of the activated form (phosphorylated) of Akt and affects tumor cell aggressiveness. In prostate cancer cell lines, we observed that transient transfection of PTEN decreased the endogenous level of PHLPPs and in contrast, the transient transfection of PHLPPs decreased the endogenous level of PTEN. Furthermore, silencing of PTEN by siRNA resulted in increased PHLPP levels. This phenomenon was not seen in non-transformed cells or in prostate stem cells. This crosstalk promoted cancer cell invasion and was controlled by epigenetically regulated processes where activation of miRs (miR-190 and miR214), the polycomb group of proteins and DNA methylation were involved. The purinergic P2X4 receptor, which has been shown to have a role in wound healing, was identified to be the mediator of this crosstalk. We also studied prostate stem cells and found this crosstalk in the TGFβ1-activated epithelial-mesenchymal transition (EMT). The crosstalk seemed to be a natural part of EMT. In summary, we identify a crosstalk between Akt phosphatases which is not present in non-transformed prostate cells but occurs in cancer cells and stem cells transformed by TGFβ-1. This crosstalk is important for cellular invasion.

BACKGROUND

Phosphatases regulate the Akt oncogene.

RESULTS

Crosstalk between Akt phosphatases in prostate cancer cells and in TGF-β1 activated stem cells but not in non-transformed cells.

CONCLUSION

This back-up mechanism facilitates invasive migration of prostate stem and cancer cells.

SIGNIFICANCE

Characterization of Akt regulation may lead to a better understanding of tumor development and to novel strategies for treatment.

MiR-92b-3p is Induced by Advanced Glycation End Products and Involved in the Pathogenesis of Diabetic Nephropathy

Purpose

The current study aims to examine the effects of advanced glycation end products (AGEs) on the microRNA (miRNA) expression profile in the kidney tissues of rats.

Methods

Wistar rats were randomly divided into three equal experiment groups: the AGE group, the RSA group, and the control group. The rats in the AGE group and the RSA group were administered with advanced glycation end products (AGEs) and rat serum albumin (RSA) via the tail vein, respectively, whereas the control group received PBS. Total RNA was prepared from the rat kidney tissues, and the miRNA expression profiles in different experiment groups were compared by microarray analysis. The expression levels of selected differential miRNAs were verified by RT-qPCR. Target gene prediction was conducted using algorithms such as TargetScan, miRanda, and PICTar. Functional analysis was performed to determine the putative biological roles of the validated miRNAs.

Results

The microarray study revealed 451 upregulated and 320 downregulated miRNAs in the AGE group compared with the RSA group (p < 0.05). Seven miRNAs, including miR-21-5p, miR-92b-3p, miR-140-3p, miR-196a-5p, miR-181b-5p, miR-186-5p, and miR-192-5p, were screened and verified using RT-qPCR, of which, the change of miR-92b-3p was the most obvious according to the miRNA expression different multiple and p < 0.05). Seven miRNAs, including miR-21-5p, miR-92b-3p, miR-140-3p, miR-196a-5p, miR-181b-5p, miR-186-5p, and miR-192-5p, were screened and verified using RT-qPCR, of which, the change of miR-92b-3p was the most obvious according to the miRNA expression different multiple and

Conclusion

The results of the current study suggested that miR-92b-3p could mediate AGE-induced development of renal abnormalities through targeting Smad7 in rats with DN.

MicroRNA-214 protects L6 skeletal myoblasts against hydrogen peroxide-induced apoptosis

MicroRNAs (miRNAs) have been reported as key gene regulators, and they control many fundamental biological processes. Previously, we demonstrated that miR-214 had a protective effect against myocardial apoptosis and myocardial fibrosis. In this study, we sought to investigate the expression of miR-214 in L6 skeletal myoblast (SKM), the regulatory effect of miR-214 on hydrogen peroxide (H₂O₂) induced cell apoptosis and the underlying mechanisms of the antiapoptotic effect. MiR-214 expression was up-regulated by H₂O₂ in a dose and time-dependent manner in L6 SKMs. To investigate the regulatory effects of miR-214 on L6 SKM, both gain-of-function and loss-of-function approaches were applied. The results showed that miR-214 improved cell survival and inhibited cell apoptosis, and blockage of miR-214 abrogated the protective effect on cell survival and resistance to apoptosis. Phosphatase and tensin homolog (PTEN) was negatively regulated by miR-214, and PTEN inhibitor obviously reversed the effect of miR-214 blockage on enhancing cell apoptosis. In addition, miR-214 up-regulated antiapoptotic protein Bcl-2, down-regulated proapoptotic protein Bax, prevented release of cytochrome c and inhibited caspase-3 activation. In summary, H₂O₂-induced injury increases miR-214 expression in L6 SKM, and miR-214 contributes to the protection of L6 SKM against apoptosis via lowering PTEN and subsequently inhibiting the mitochondrial-mediated caspase-dependent apoptotic signaling pathway.

MiR-214-3p exacerbates kidney damages and inflammation induced by hyperlipidemic pancreatitis complicated with acute renal injury

AIMS

Acute pancreatitis (AP) is usually complicated with multiple organ insufficiency, including renal injury. Hyperlipidemia is regarded as a risk factor to induce AP. High-fat diet-induced hyperlipidemic pancreatitis (HP) increased nowadays and showed more severe symptoms and complications than other AP. However, detailed mechanisms or mediators involved in HP complicated with acute renal injury were less studied. Here, we aimed to study how miR-214 expresses in the HP and whether miR-214 has functions to regulate pathological kidney damages induced by HP.

MAIN METHODS

Sprague-Dawley rats were adopted to establish HP model complicated with acute renal injury through long-term high-fat diet and sodium taurocholic injection. Models were injected with LV-rno-miR-214-3p or LV-anti-rno-miR-214-3p to exogenously regulate miR-214-3p to study its impacts on HP via a series of molecular and histological experiments.

KEY FINDINGS

MiR-214-3p was found to be up-regulated in the kidney, pancreas and serum of HP rats and also could intensify the pathological alterations, kidney and pancreas damages and fibrosis induced by HP. Inflammatory response in HP was enhanced when miR-214-3p was overexpressed. Besides, miR-214-3p up-regulation was showed to inhibit PTEN expression but increased P-Akt levels in the HP kidney, which might be a possible mechanism to induce severe symptoms of pancreatitis. Knockdown of miR-214-3p showed opposite effects.

SIGNIFICANCE

MiR-214-3p is indicated to exacerbate the tissue damages and inflammatory response caused by HP complicated with acute renal injury, which may provide a novel therapeutic perspective targeting miR-214-3p to treat HP with acute renal injury.

Diagnostic and theranostic microRNAs in the pathogenesis of atherosclerosis

MicroRNAs (miRNAs) are a group of small single strand and noncoding RNAs that regulate several physiological and molecular signalling pathways. Alterations of miRNA expression profiles may be involved with pathophysiological processes underlying the development of atherosclerosis and cardiovascular diseases, including changes in the functions of the endothelial cells and vascular smooth muscle cells, such as cell proliferation, migration and inflammation, which are involved in angiogenesis, macrophage function and foam cell formation. Thus, miRNAs can be considered to have a crucial role in the progression, modulation and regulation of every stage of atherosclerosis. Such potential biomarkers will enable us to predict therapeutic response and prognosis of cardiovascular diseases and adopt effective preclinical and clinical treatment strategies. In the present review article, the current data regarding the role of miRNAs in atherosclerosis were summarized and the potential miRNAs as prognostic, diagnostic and theranostic biomarkers in preclinical and clinical studies were further discussed. The highlights of this review are expected to present opportunities for future research of clinical therapeutic approaches in vascular diseases resulting from atherosclerosis with an emphasis on miRNAs.

The HOTAIR/miR-214/ST6GAL1 crosstalk modulates colorectal cancer procession through mediating sialylated c-Met via JAK2/STAT3 cascade

Background

The regulatory non-coding RNAs, including long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), emerge as pivotal markers during tumor progression. Abnormal sialylated glycoprotein often leads to the malignancy of colorectal cancer (CRC).

Methods

Differential levels of HOTAIR and ST6GAL1 are analyzed by qRT-PCR. Functionally, CRC cell proliferation, aggressiveness and apoptosis are measured through relevant experiments, including CCK8 assay, colony formation assay, transwell assay, western blot and flow cytometry. Dual-luciferase reporter gene assay and RIP assay confirm the direct interaction between HOTAIR and miR-214. The lung metastasis, liver metatstasis and xenografts nude mice models are established to show the in vivo effect of HOATIR.

Results

Here, differential levels of HOTAIR and ST6GAL1 are primarily observed in CRC samples and cells. Upregulated HOTAIR and ST6GAL1 are crucial predictors for poor CRC prognosis. Altered level of ST6GAL1 modulates CRC malignancy. Furthermore, ST6GAL1 and HOTAIR are confirmed as the direct targets of miR-214, and ST6GAL1 is regulated by HOTAIR via sponging miR-214. ST6GAL1 induces the elevated metabolic sialylation of c-Met, which is co-mediated by HOTAIR and miR-214. Sialylated c-Met affects the activity of JAK2/STAT3 pathway. The regulatory role of HOTAIR/miR-214/ST6GAL1 axis also impacts CRC procession. In addition, HOTAIR mediates lung metastasis, liver metastasis and tumorigenesis in vivo. ShHOTAIR and AMG-208 are combined to inhibit tumorigenesis for successful drug development.

Conclusion

The HOTAIR/miR-214/ST6GAL1 axis commands the CRC malignancy by modifying c-Met with sialylation and activating JAK2/STAT3 pathway. Our study presents novel insights into CRC progression and provided prospective therapeutic target for CRC.

The Modern Western Diet Rich in Advanced Glycation End-Products (AGEs): An Overview of Its Impact on Obesity and Early Progression of Renal Pathology

Advanced glycation end-products (AGEs) are an assorted group of molecules formed through covalent bonds between a reduced sugar and a free amino group of proteins, lipids, and nucleic acids. Glycation alters their structure and function, leading to impaired cell function. They can be originated by physiological processes, when not counterbalanced by detoxification mechanisms, or derive from exogenous sources such as food, cigarette smoke, and air pollution. Their accumulation increases inflammation and oxidative stress through the activation of various mechanisms mainly triggered by binding to their receptors (RAGE). So far, the pathogenic role of AGEs has been evidenced in inflammatory and chronic diseases such as chronic kidney disease, cardiovascular disease, and diabetic nephropathy. This review focuses on the AGE-induced kidney damage, by describing the molecular players involved and investigating its link to the excess of body weight and visceral fat, hallmarks of obesity. Research regarding interventions to reduce AGE accumulation has been of great interest and a nutraceutical approach that would help fighting chronic diseases could be a very useful tool for patients’ everyday lives.

Long noncoding RNA MALAT1 regulates sepsis in patients with burns by modulating miR‑214 with TLR5

The present study aimed to identify the involvement of the dysregulation of the metastasis‑associated lung adenocarcinoma transcript‑1 (MALAT1)/microRNA (miR)‑214/Toll‑like receptor (TLR)5 signaling pathway in the development of post‑burn sepsis. THP‑1 cells were used in the present study, in addition to 8‑10 week‑old mice. ELISA analysis was performed to examine the expression levels of inflammation‑associated factors. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis and western blotting were performed to analyze the influence of burns or burns with infection on the production of MALAT1, miR‑214 and TLR5. Commonly‑used software and a luciferase assay was used to confirm the target gene of miR‑214. RT‑qPCR analysis and western blotting were performed to elucidate the effects of lipopolysaccharide (LPS), miR‑214 and MALAT1 on the expression of miR‑214, TLR5, tumor necrosis factor (TNF)‑α, interleukin (IL)‑6 and IL‑10. Burn injury increased TLR5, TNF‑α, IL‑6 and IL‑10 expression levels, which were abolished by treatment with MALAT1. miR‑214 directly targeted TLR5 by binding to the TLR5 3' untranslated region (ITR), and the luciferase activity of the wild‑type, and not the mutant, TLR5 3'UTR was reduced following transfection with miR‑214. In cells not treated with LPS, MALAT1 and anti‑miR‑214 significantly enhanced TLR5, TNF‑α, IL‑6 and IL‑10 expression, and repressed miR‑214 production; whereas, miR‑214 and MALAT1 short hairpin (sh)RNA decreased TLR5, TNF‑α, IL‑6 and IL‑10 expression levels, and increased miR‑214 expression. In cells treated with LPS, LPS reduced miR‑214 expression and increased TLR5, TNF‑α, IL‑6 and IL‑10 expression compared with LPS‑untreated cells, and the effects of MALAT1, anti‑miR‑214, miR‑214 and MALAT1 shRNA on TLR5, TNF‑α, IL‑6 and IL‑10 were the same as in LPS‑untreated cell. The results of the present study indicated the association between the dysregulation of MALAT1/miR‑214/TLR5 and the risk of post‑burn sepsis.

miR-214 ameliorates acute kidney injury via targeting DKK3 and activating of Wnt/β-catenin signaling pathway

Background

miR-214 was demonstrated to be upregulated in models of renal disease and promoted fibrosis in renal injury independent of TGF-β signaling in vivo. However, the detailed role of miR-214 in acute kidney injury (AKI) and its underlying mechanism are still largely unknown.

Methods

In this study, an I/R-induced rat AKI model and a hypoxia-induced NRK-52E cell model were used to study AKI. The concentrations of kidney injury markers serum creatinine, blood urea nitrogen, and kidney injury molecule-1 were measured. The expressions of miR-214, tumor necrosis factor-α, interleukin (IL)-1β, IL-6, were detected by RT-qPCR. The protein levels of Bcl-2, Bax, Dickkopf-related protein 3, β-catenin, c-myc, and cyclinD1 were determined by western blot. Cell apoptosis and caspase 3 activity were evaluated by flow cytometry analysis and caspase 3 activity assay, respectively. Luciferase reporter assay was used to confirm the interaction between miR-214 and Dkk3.

Results

miR-214 expression was induced in ischemia–reperfusion (I/R)-induced AKI rat and hypoxic incubation of NRK-52E cells. Overexpression of miR-214 alleviated hypoxia-induced NRK-52E cell apoptosis while inhibition of miR-214 expression exerted the opposite effect. Dkk3 was identified as a target of miR-214. Anti-miR-214 abolished the inhibitory effects of DKK3 knockdown on hypoxia-induced NRK-52E cell apoptosis by inactivation of Wnt/β-catenin signaling. Moreover, miR-214 ameliorated AKI in vivo by inhibiting apoptosis and fibrosis through targeting Dkk3 and activating Wnt/β-catenin pathway.

Conclusion

miR-214 ameliorates AKI by inhibiting apoptosis through targeting Dkk3 and activating Wnt/β-catenin signaling pathway, offering the possibility of miR-214 in the therapy of ischemic AKI.

Electronic supplementary material

The online version of this article (10.1186/s40659-018-0179-2) contains supplementary material, which is available to authorized users.

miR-5591-5p regulates the effect of ADSCs in repairing diabetic wound via targeting AGEs/AGER/JNK signaling axis

Advanced glycation end products/advanced glycation end products receptor (AGEs/AGER) interaction triggers reactive oxygen species (ROS) generation and activates downstream signal pathways and induces apoptosis in endothelial progenitor cells. A number of studies have revealed the involvement of microRNAs (miRNAs) in regulating intracellular ROS production and apoptosis. However, few studies explore the role of miRNAs in regulating the effect of adipose tissue-derived stem cells (ADSCs) in repairing diabetic wound and the associated cellular mechanisms remain unclear. In this study, ADSCs were exposed to AGEs, then siRNA for AGER was transfected into ADSCs. We found that AGEs/AGER axis induced ROS generation and apoptosis in ADSCs. AGEs treatment downregulated miR-5591-5p in ADSCs, which directly targeted AGER. miR-5591-5p suppressed AGEs/AGER axis-mediated ROS generation and apoptosis in ADSCs in vitro. In addition, miR-5591-5p promoted cell survival and enhanced the ability of ADSCs for repairing cutaneous wound in vivo. Furthermore, we confirmed that c-jun kinase (JNK) signal was involved in the inhibitory effect of miR-5591-5p on AGEs/AGER axis-induced ROS generation and apoptosis in ADSCs. Thus, these results indicated that miR-5591-5p targeting AGEs/AGER/JNK signaling axis possibly regulates the effect of ADSCs in repairing diabetic wound.

Endogenous Secretory Receptor for Advanced Glycation End Products Protects Endothelial Cells from AGEs Induced Apoptosis

Endogenous secretory receptor for advanced glycation end products (esRAGE) binds extracellular RAGE ligands and blocks RAGE activation on the cell surface, protecting endothelial cell function. However, the underlying mechanism remains unclear. Endothelial cells overexpressing the esRAGE gene were generated using a lentiviral vector. Then, quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to assess esRAGE mRNA and protein levels, respectively. Hoechst-PI double staining was used to assess apoptosis. Western blot and qRT-PCR were used to assess the expression levels of apoptosis-related factors and the proinflammatory cytokine NF-кB. Compared with the control group, AGEs significantly induced endothelial cell apoptosis, which was significantly reduced by esRAGE overexpression. Incubation with AGEs upregulated the proapoptotic factor Bax and downregulated the antiapoptotic factor Bcl-2. Overexpression of esRAGE reduced Bax expression induced by AGEs and increased Bcl-2 levels. Furthermore, AGEs increased the expression levels of proinflammatory cytokine NF-кB, which were reduced after esRAGE overexpression. esRAGE protects endothelial cells from AGEs associated apoptosis, by downregulating proapoptotic (Bax) and inflammatory (NF-кB) factors and upregulating the antiapoptotic factor Bcl-2.

Formula derived Maillard reaction products in post-weaning intrauterine growth-restricted piglets induce developmental programming of hepatic oxidative stress independently of microRNA-21 and microRNA-155

We recently reported augmentation of lipid peroxidation products in the liver of intrauterine growth-restricted (IUGR) piglets fed a high load of Maillard reaction products (MRPs) during suckling period. The underlying mechanisms of MRPs effects remain unknown. Here, we studied the long-term impact of MRPs exposure on liver oxidative status of IUGR juvenile pigs. Livers of 54-day-old pigs suckled with formula containing either a high (HHF, n=8) or a low (LHF: n=8) load of MRPs were analyzed for protein carbonylation levels , activities and messenger RNA (mRNA) expression of glutathione (GSH) and main antioxidant regulators of redox homeostasis [Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were measured. In addition, mRNA levels of miRNA-21 and miRNA-155 were measured. The liver of HHF group exhibited a high level of lipid peroxidation with significantly increased expression and activity of SOD. Further in liver of HHF group, CAT activity was decreased as compared with LHF group, though with comparable total protein carbonyl contents, GSH contents, and expression of GPx and microRNAs (miRNA-21 and miRNA-155). Our findings suggest that the potential mechanism of MRPs-mediated oxidative stress programming in liver of IUGR piglets may occur via impairment of antioxidant defenses.

Total flavones of Abelmoschus manihot improve diabetic nephropathy by inhibiting the iRhom2/TACE signalling pathway activity in rats

CONTEXT

Total flavones extracted from Abelmoschus manihot L. (Malvaceae) medic (TFA) have been proven clinically effective at improving renal inflammation and glomerular injury in chronic kidney disease (CKD).

OBJECTIVE

This study evaluated the function of TFA as an inhibitor of iRhom2/TACE (tumour necrosis factor-α converting enzyme) signalling and investigated its anti-DN (diabetic nephropathy) effects in a DN rat model.

MATERIALS AND METHODS

In vitro, cells were treated with 200 μg/mL advanced glycation end products (AGEs), and then co-cultured with 20 μg/mL TFA for 24 h. Real time PCR, western blotting and co-immunoprecipitation assays were performed. In vivo, DN was induced in 8 week old male Sprague-Dawley rats via unilateral nephrectomy and intraperitoneal injection of streptozotocin, then TFA were administered to rats by gavage for 12 weeks at three different doses (300, 135 and 75 mg/kg/d). 4-Phenylbutanoic acid (2.5 mg/kg/d) was used as a positive control.

RESULTS

IC₅₀ of TFA is 35.6 μM in HK2 and 39.6 μM in HRMC. TFA treatment (20 μM) inhibited the activation of iRhom2/TACE signalling in cultured cells induced by AGEs. LD₅₀>26 g/kg and ED₅₀=67 mg/kg of TFA in rat by gavage, TFA dose-dependently downregulated the expression of proinflammatory cytokines and exerted anti-inflammatory effects significantly though inhibiting the activation of iRhom2/TACE signalling.

DISCUSSION AND CONCLUSIONS

Our results show that TFA could dose-dependently ameliorate renal inflammation by inhibiting the activation of iRhom2/TACE signalling and attenuating ER stress. These results suggest that TFA has potential therapeutic value for the treatment of DN in humans.

microRNA expression signatures and parallels between monocyte subsets and atherosclerotic plaque in humans

Small non-coding microRNAs (miRNAs) have emerged to play critical roles in cardiovascular biology. Monocytes critically drive atherosclerotic lesion formation, and can be subdivided into a classical and non-classical subset. Here we scrutinised the miRNA signature of human classical and non-classical monocytes, and compared miRNA expression profiles of atherosclerotic plaques from human carotid arteries and healthy arteries. We identified miRNAs to be differentially regulated with a two-fold or higher difference between classical and non-classical monocyte subsets. Moreover, comparing miRNA expression in atherosclerotic plaques compared to healthy arteries, we observed several miRNAs to be aberrantly expressed, with the majority of miRNAs displaying a two-fold or higher increase in plaques and only few miRNAs being decreased. To elucidate similarities in miRNA signatures between monocyte subsets and atherosclerotic plaque, expression of miRNAs highly abundant in monocytes and plaque tissues were compared. Several miRNAs were found in atherosclerotic plaques but not in healthy vessels or either monocyte subset. However, we could identify miRNAs co-expressed in plaque tissue and classical monocytes (miR-99b, miR-152), or non-classical monocytes (miR-422a), or in both monocytes subsets. We thus unravelled candidate miRNAs, which may facilitate our understanding of monocyte recruitment and fate during atherosclerosis, and may serve as therapeutic targets for treating inflammatory vascular diseases.

Note: The editorial process for this article was fully handled by Prof. G. Y. H. Lip, Editor-in-Chief.

Therapeutic potential of microRNAs for the treatment of renal fibrosis and CKD

Chronic kidney disease (CKD), defined as reduced glomerular filtration rate, is increasingly becoming a major public health issue. At the histological level, renal fibrosis is the final common pathway leading to end-stage renal disease, irrespective of the initial injury. According to this view, antifibrotic agents should slow or halt the progression of CKD. However, due to multiple overlapping pathways stimulating fibrosis, it has been difficult to develop antifibrotic drugs that delay or reverse the progression of CKD. MicroRNAs (miRNAs) are small noncoding RNA molecules, 18-22 nucleotides in length, that control many developmental and cellular processes as posttranscriptional regulators of gene expression. Emerging evidence suggests that miRNAs targeted against genes involved in renal fibrosis might be potential candidates for the development of antifibrotic therapies for CKD. This review will discuss some of the miRNAs, such as Let-7, miR-21,-29, -192, -200,-324, -132, -212, -30, -126, -433, -214, and -199a, that are implicated in renal fibrosis and the potential to exploit these molecular targets for the treatment of CKD.

Cross talk between miR-214 and PTEN attenuates glomerular hypertrophy under diabetic conditions

Glomerular mesangial cells (MCs) hypertrophy is one of the earliest pathological abnormalities in diabetic nephropathy (DN), which correlates with eventual glomerulosclerosis. This study aimed to investigate the therapeutic role of miRNA in diabetic glomerular MCs hypertrophy and synthesis of extracellular matrix (ECM). Microarray analysis revealed a significant up-regulation of miR-214 in the renal cortex of diabetic db/db mice, which was confirmed by real-time PCR of isolated glomeruli and primary cultured human MCs. In vitro studies showed that inhibition of miR-214 significantly reduced expression of α-SMA, SM22 and collagen IV, and partially restored phosphatase and tensin homolog (PTEN) protein level in high glucose-stimulated human MCs. Furthermore, we identified PTEN as the target of miR-214 by a luciferase assay in HEK293 cells. Moreover, overexpression of PTEN ameliorated miR-214-mediated diabetic MC hypertrophy while knockdown of PTEN mimicked the MC hypertrophy. In vivo study further confirmed that inhibition of miR-214 significantly decreased the expression of SM22, α-SMA and collagen IV, partially restored PTEN level, and attenuated albuminuria and mesangial expansion in db/db mice. In conclusion, cross talk between miR-214 and PTEN attenuated glomerular hypertrophy under diabetic conditions in vivo and in vitro. Therefore, miR-214 may represent a novel therapeutic target for DN.

RNA Regulation of Lipotoxicity and Metabolic Stress

Noncoding RNAs are an emerging class of nonpeptide regulators of metabolism. Metabolic diseases and the altered metabolic environment induce marked changes in levels of microRNAs and long noncoding RNAs. Furthermore, recent studies indicate that a growing number of microRNAs and long noncoding RNAs serve as critical mediators of adaptive and maladaptive responses through their effects on gene expression. The metabolic environment also has a profound impact on the functions of classes of noncoding RNAs that have been thought primarily to subserve housekeeping functions in cells-ribosomal RNAs, transfer RNAs, and small nucleolar RNAs. Evidence is accumulating that these RNAs are also components of an integrated cellular response to the metabolic milieu. This Perspective discusses the different classes of noncoding RNAs and their contributions to the pathogenesis of metabolic stress.

Identification of side- and shear-dependent microRNAs regulating porcine aortic valve pathogenesis

Aortic valve (AV) calcification is an inflammation driven process that occurs preferentially in the fibrosa. To explore the underlying mechanisms, we investigated if key microRNAs (miRNA) in the AV are differentially expressed due to disturbed blood flow (oscillatory shear (OS)) experienced by the fibrosa compared to the ventricularis. To identify the miRNAs involved, endothelial-enriched RNA was isolated from either side of healthy porcine AVs for microarray analysis. Validation using qPCR confirmed significantly higher expression of 7 miRNAs (miR-100, -130a, -181a/b, -199a-3p, -199a-5p, and -214) in the fibrosa versus the ventricularis. Upon bioinformatics analysis, miR-214 was selected for further investigation using porcine AV leaflets in an ex vivo shear system. Fibrosa and ventricularis sides were exposed to either oscillatory or unidirectional pulsatile shear for 2 days and 3 & 7 days in regular and osteogenic media, respectively. Higher expression of miR-214, increased thickness of the fibrosa, and calcification was observed when the fibrosa was exposed to OS compared to the ventricularis. Silencing of miR-214 by anti-miR-214 in whole AV leaflets with the fibrosa exposed to OS significantly increased the protein expression of TGFβ1 and moderately increased collagen content but did not affect AV calcification. Thus, miR-214 is identified as a side- and shear-dependent miRNA that regulates key mechanosensitive gene in AV such as TGFβ1.

miR-223 contributes to the AGE-promoted apoptosis via down-regulating insulin-like growth factor 1 receptor in osteoblasts

miR-223 inhibits the advanced glycation end product (AGE)-promoted apoptosis in osteoblasts.

Advanced glycation end products (AGEs) have been confirmed to induce bone quality deterioration in diabetes mellitus (DM), and to associate with abnormal expression of miRNAs in DM patients or in vitro. Recently, miRNAs have been recognized to mediate the onset or progression of DM. In the present study, we investigated the regulation on miR-223 level by AGE-BSA treatment in osteoblast-like MC3T3-E1 cells, with real-time quantitative PCR assay. And then we examined the inhibition of insulin-like growth factor 1 receptor (IGF-1R) expression by miR-223, via targeting of the 3′ UTR of IGF-1R with real-time quantitative PCR, western blotting and luciferase reporter assay. Then we explored the regulation of miR-223 and IGF-1R levels, via the lentivirus-mediated miR-223 inhibition and IGF-1R overexpression in the AGE-BSA-induced apoptosis in MC3T3-E1 cells. It was demonstrated that AGE-BSA treatment with more than 100 μg/ml significantly up-regulated miR-223 level, whereas down-regulated IGF-1R level in MC3T3-E1 cells. And the up-regulated miR-223 down-regulated IGF-1R expression in both mRNA and protein levels, via targeting the 3′ UTR of IGF-1R. Moreover, though the AGE-BSA treatment promoted apoptosis in MC3T3-E1 cells, the IGF-1R overexpression or the miR-223 inhibition significantly attenuated the AGE-BSA-promoted apoptosis in MC3T3-E1 cells. In summary, our study recognized the promotion of miR-223 level by AGE-BSA treatment in osteoblast-like MC3T3-E1 cells. The promoted miR-223 targeted IGF-1R and mediated the AGE-BSA-induced apoptosis in MC3T3-E1 cells. It implies that miR-223 might be an effective therapeutic target to antagonize the AGE-induced damage to osteoblasts in DM.

miR-214 promotes osteoclastogenesis by targeting Pten/PI3k/Akt pathway

microRNA is necessary for osteoclast differentiation, function and survival. It has been reported that miR-199/214 cluster plays important roles in vertebrate skeletal development and miR-214 inhibits osteoblast function by targeting ATF4. Here, we show that miR-214 is up-regulated during osteoclastogenesis from bone marrow monocytes (BMMs) with macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL) induction, which indicates that miR-214 plays a critical role in osteoclast differentiation. Overexpression of miR-214 in BMMs promotes osteoclastogenesis, whereas inhibition of miR-214 attenuates it. We further find that miR-214 functions through PI3K/Akt pathway by targeting phosphatase and tensin homolog (Pten). In vivo, osteoclast specific miR-214 transgenic mice (OC-TG214) exhibit down-regulated Pten levels, increased osteoclast activity, and reduced bone mineral density. These results reveal a crucial role of miR-214 in the differentiation of osteoclasts, which will provide a potential therapeutic target for osteoporosis.

Advanced glycation end products activate the miRNA/RhoA/ROCK2 pathway in endothelial cells

OBJECTIVE

AGEs induce endothelial cell dysfunction in HUVECs, resulting in ROS production and triggering apoptosis. This study sought to identify miRNAs involved in AGE-induced endothelial cell injury.

METHODS

Microarray analysis to identify miRNAs altered with AGE stimulation was undertaken, and results were confirmed using real-time quantitative polymerase chain reaction. The interaction of miRNAs with the RhoA and ROCK2 genes was confirmed using luciferase assays, and their effects on expression were determined using Western blot analysis. The effects of AGEs and miRNAs on endothelial cell permeability were assessed.

RESULTS

AGEs induced ROS production and apoptosis of HUVECs (p < 0.05). AGE-induced miR-200b and miR-200c downregulation led to increased expression of their target genes, RhoA and ROCK, respectively. AGE-induced endothelial cell permeability and F-actin expression were significantly reduced with both miR-200b and miR-200c mimics (p < 0.05). Furthermore, AGE-induced stress fiber formation was reduced in cells treated with miR-200b mimics.

CONCLUSION

miR-200b and miR-200c are suppressed in AGE-induced endothelial cell injury, resulting in unregulated RhoA/ROCK2 signaling. Further studies are necessary to evaluate the therapeutic value of targeting miRNAs or their target genes for treatment of vascular diseases.

Scavenger receptors and non-coding RNAs: relevance in atherogenesis

Scavenger receptors (SRs), which recognize modified low-density lipoprotein (LDL) by oxidation or acetylation, are a group of receptors on plasma membrane of macrophages and other cell types. These receptors by facilitating modified LDL uptake are a primary step in the intracellular accumulation of modified LDL and formation of fatty streak. Non-coding RNAs (ncRNAs) are a group of functional RNA nucleotides that are not translated into protein, and include microRNAs (miRs), snoRNAs, siRNAs, snRNAs, exRNAs, piRNAs, and the long ncRNAs (lncRNAs). Recently, ncRNAs have received much attention due to their effects in a variety of disease states such as atherosclerotic cardiovascular disease and cancers. A host of ncRNAs, such as miRs and lncRNAs, have been found to be involved in the regulation of SRs and the inflammatory cascade and subsequently atherosclerosis. Here, we review this important area to create interest in this growing field among researchers and clinicians alike.

MicroRNAs in diabetic nephropathy: functions, biomarkers, and therapeutic targets

MicroRNAs (miRNAs) are short noncoding RNAs that regulate gene expression by posttranscriptional and epigenetic mechanisms and thereby affect many cellular processes and disease states. Over 2,000 human mature miRNAs have been identified, and at least 60% of all human protein-coding genes are known to be regulated by miRNAs. MicroRNA biogenesis involves classical transcription regulation and processing by key ribonucleases, as well as other protein factors and epigenetic mechanisms. Diabetic nephropathy (DN), a severe microvascular complication frequently associated with diabetes mellitus, is a major cause of renal failure. Although several mechanisms of regulation of key renal genes implicated in DN pathogenesis have been identified, a greater understanding is needed to develop better treatment modalities. Recent studies show that miRNAs induced in renal cells in vivo and in vitro under diabetic conditions can promote the accumulation of extracellular matrix proteins related to fibrosis and glomerular dysfunction. In this review, we highlight the significance of the expression of miRNAs in various stages of DN and emerging approaches to exploit them as biomarkers for early detection or novel therapeutic targets to prevent progression of DN.

MicroRNA expression profiling of human blood monocyte subsets highlights functional differences

Within human blood there are two subsets of monocytes that can be identified by differential expression of CD16. Although numerous phenotypic and functional differences between the subsets have been described, little is known of the mechanisms underlying the distinctive properties of the two subsets. MicroRNAs (miRNAs) are small non-coding RNAs that can regulate gene expression through promoting mRNA degradation or repressing translation, leading to alterations in cellular processes. Their potential influence on the functions of monocyte subsets has not been investigated. In this study, we employed microarray analysis to define the miRNA expression profile of human monocyte subsets. We identified 66 miRNAs that were differentially expressed (DE) between CD16(+) and CD16(-) monocytes. Gene ontology analysis revealed that the predicted targets of the DE miRNAs were predominantly associated with cell death and cellular movement. We validated the functional impacts of selected DE miRNAs in CD16(-) monocytes, over-expression of miR-432 significantly increases apoptosis, and inhibiting miR-19a significantly reduces cell motility. Furthermore, we found that miR-345, another DE miRNA directly targets the transcription factor RelA in monocytes, which resulted in the differential expression of RelA in monocyte subsets. This implicates miR-345 indirect regulation of many genes downstream of RelA, including important inflammatory mediators. Together, our data show that DE miRNAs could contribute substantially to regulating the functions of human blood monocytes.

Uremic Toxicity of Advanced Glycation End Products in CKD

Advanced glycation end products (AGEs), a heterogeneous group of compounds formed by nonenzymatic glycation reactions between reducing sugars and amino acids, lipids, or DNA, are formed not only in the presence of hyperglycemia, but also in diseases associated with high levels of oxidative stress, such as CKD. In chronic renal failure, higher circulating AGE levels result from increased formation and decreased renal clearance. Interactions between AGEs and their receptors, including advanced glycation end product-specific receptor (RAGE), trigger various intracellular events, such as oxidative stress and inflammation, leading to cardiovascular complications. Although patients with CKD have a higher burden of cardiovascular disease, the relationship between AGEs and cardiovascular disease in patients with CKD is not fully characterized. In this paper, we review the various deleterious effects of AGEs in CKD that lead to cardiovascular complications and the role of these AGEs in diabetic nephropathy. We also discuss potential pharmacologic approaches to circumvent these deleterious effects by reducing exogenous and endogenous sources of AGEs, increasing the breakdown of existing AGEs, or inhibiting AGE-induced inflammation. Finally, we speculate on preventive and therapeutic strategies that focus on the AGE-RAGE axis to prevent vascular complications in patients with CKD.

Anti-fibrotic Role of miR-214 in Thioacetamide-induced Liver Cirrhosis in Rats

An increasing number of studies have focused on the role of microRNAs in liver fibrosis/cirrhosis. miR-214 has recently attracted more attention as a fibrosis-related factor; however, the molecular mechanisms in hepatic fibrogenesis remain largely unknown. Here, we investigate the pathological role of miR-214 during progression of liver cirrhosis in rats. Rats were injected intraperitoneally with thioacetamide at a dose of 100 mg/kg body weight, twice a week. The liver was collected at post first injection weeks 5, 10, 15, and 20. Hepatic expression of miR-214 was analyzed by real-time polymerase chain reaction, in situ hybridization, and laser microdissection. The effects of miR-214 overexpression were investigated by in vitro transfection using fibroblastic MT-9 cells. miR-214 was highly upregulated in the fibrotic area in parallel with the cirrhosis progression. miR-214 overexpression in MT-9 cells under transforming growth factor-β1 stimulation resulted in decreased cell number and increased expression of cleaved caspase 3 and decreased expression of α-smooth muscle actin, suggesting that miR-214 induces apoptosis and inhibits myofibroblast differentiation in fibroblastic cells under stimulation of fibrogenic factors. These data indicate an anti-fibrotic role of miR-214 in chemically induced liver fibrosis/cirrhosis.

Involvement of microRNA214 and transcriptional regulation in reductions in mevalonate pyrophosphate decarboxylase mRNA levels in stroke-prone spontaneously hypertensive rat livers

Hypocholesterolemia has been epidemiologically identified as one of the causes of stroke (cerebral hemorrhage). We previously reported that lower protein levels of mevalonate pyrophosphate decarboxylase (MPD), which is responsible for reducing serum cholesterol levels in stroke-prone spontaneously hypertensive rats (SHRSP), in the liver were caused by a reduction in mRNA levels. However, the mechanism responsible for reducing MPD expression levels in the SHRSP liver remains unclear. Thus, we compared microRNA (miR)-214 combined with the 3'-untranslated region of MPD mRNA and heterogeneous nuclear RNA (hnRNA) between SHRSP and normotensive Wistar Kyoto rats (WKY). miR-214 levels in the liver were markedly higher in SHRSP than in WKY, whereas hnRNA levels were significantly lower. These results indicate that the upregulation of miR-214 and downregulation of MPD transcription in the liver both play a role in the development of hypocholesterolemia in SHRSP.

MicroRNA-193a-3p Reduces Intestinal Inflammation in Response to Microbiota via Down-regulation of Colonic PepT1

Intestinal inflammation is characterized by epithelial disruption, leading to the loss of barrier function, recruitment of immune cells, and host immune responses to gut microbiota. PepT1, a di/tripeptide transporter that uptakes bacterial products, is up-regulated in inflamed colon tissue, which implies its role in bacterium-associated intestinal inflammation. Although microRNA (miRNA)-mediated gene regulation has been found to be involved in various processes of inflammatory bowel disease (IBD), the biological function of miRNAs in the pathogenesis of IBD remains to be explored. In this study we detected miRNA expression patterns in colon tissues during colitis and investigated the mechanism underlying the regulation of colonic PepT1 by miRNAs. We observed an inverse correlation between PepT1 and miR-193a-3p in inflamed colon tissues with active ulcerative colitis, and we further demonstrated that miR-193a-3p reduced PepT1 expression and activity as a target gene and subsequently suppressed the NF-κB pathway. Intracolonic delivery of miR-193a-3p significantly ameliorated dextran sodium sulfate-induced colitis, whereas the overexpression of colonic PepT1 via PepT1 3'-untranslated region mutant lentivirus vector abolished the anti-inflammatory effect of miR-193a-3p. Furthermore, antibiotic treatment eliminated the difference in the dextran sodium sulfate-induced inflammation between the presence and absence of miR-193a-3p. These findings suggest that miR-193a-3p regulation of PepT1 mediates the uptake of bacterial products and is a potent mechanism during the colonic inflammation process. Overall, we believe miR-193a-3p may be a potent regulator of colonic PepT1 for maintaining intestinal homeostasis.