Changes In miR Expression Research Articles

Host microRNAs are decreased in pediatric solid-organ transplant recipients during EBV+ Post-transplant Lymphoproliferative Disorder.

Post-transplant lymphoproliferative disorder (PTLD) is a serious complication of solid organ transplantation. Predisposing factors include primary Epstein-Barr virus (EBV) infection, reactivation of EBV in recipient B cells, and decreased T cell immunity due to immunosuppression. In our previous studies EBV infection was demonstrated to markedly alter the expression of host B cell microRNA (miR). Specifically, miR-194 expression was uniquely suppressed in EBV+ B cell lines from PTLD patients and the 3’untranslated region of IL-10 was determined to be targeted by miR-194. Although EBV has been shown to regulate host miR expression in B cell lymphoma cell lines, the expression of miRs in the circulation of patients with EBV-associated PTLD has not been studied. The objective of this study was to determine if changes in miR expression are associated with EBV+ PTLD. In this study, we have shown that miR-194 is significantly decreased in EBV+PTLD tumors and that additional miRs, including miRs-17, 19 and 106a are also reduced in EBV+PTLD as compared to EBV-PTLD. We quantitated the levels of miRs-17, 19, 106a, 155, and 194 in the plasma and extracellular vesicles (EV; 50-70 nm as determined by nanoparticle tracking analysis) from pediatric recipients of solid organ transplants with EBV+ PTLD+ that were matched 1:2 with EBV+ PTLD- pediatric transplant recipients as part of the NIH-sponsored Clinical Trials in Organ Transplantation in Children, (CTOTC-06) study. Levels of miRs-17, 19, 106a, and 194 were reduced in the plasma and extracellular vesicles (EV) of EBV+ PTLD+ group compared to matched controls, with miRs-17 (p = 0.034; plasma), miRs-19 (p = 0.029; EV) and miR-106a (p = 0.007; plasma and EV) being significantly reduced. Similar levels of miR-155 were detected in the plasma and EV of all pediatric SOT recipients. Importantly, ~90% of the cell-free miR were contained within the EV supporting that EBV+ PTLD tumor miR are detected in the circulation and suggesting that EVs, containing miRs, may have the potential to target and regulate cells of the immune system. Further development of diagnostic, mechanistic and potential therapeutic uses of the miRs in PTLD is warranted.

The Vascular Basis of Takotsubo Syndrome

Takotsubo Syndrome (TTS) is an unmet medical need as there is no “standard of care” with an in‐hospital mortality rate equivalent to patients with an acute myocardial infarction. Characteristic of TTS is systolic ballooning of the left ventricular (LV) apex, simultaneous with contraction of the base. The mechanism(s) underlying this disassociation of mechanical activities in the LV is(are) unknown, however, a murine model may provide insights into this clinical conundrum. Previously, we found that mice null for Kv1.5 channels (KO), a model of inadequate coronary metabolic dilation, exhibit TTS (KOTTC) when stressed by transaortic constriction (TAC). Because of the microvascular link to inadequate dilation, we hypothesized that coronary vessels in the base and the apex of the left ventricle have different phenotypes as shown by variations in gene expression. To address this, we dissected small coronary arteries from the LV apex and base of KO control mice (KOC) and following TAC when the mice exhibited profound TTS. Ventricular function (fractional shortening [FS]) was calculated from echocardiographic (Echo) imaging. The Echo measurements revealed FS of 39±3% and 34±6% in LV base and apex, respectively, in KOC (P=NS). In contrast, FS was significantly changed in KOTTC with FS of ‐9±4% in LV apex and 25±11% in the base (P<0.05, with the negative FS representing systolic ballooning). After the Echo measurements, hearts were removed, placed in a chilled dish, and vessels immediately isolated from the LV apex and base (using a dissecting microscope) were placed in Trizol and flash frozen. Total RNA was extracted and used for RNAseq to profile the transcriptomes of small arteries from the apex and base of KOC and KOTTC groups. RNAseq revealed expression of 197 genes significantly changed in the LV apex versus base of KOTTC mice (P<0.05). The 197 genes represented 24 distinct pathways with some of the most significant comprising neuroactive‐receptor ligand interactions, miRs in cancer, and complement and coagulation cascades. The endothelin pathway was significantly upregulated in small arteries of the LV apex compared to base in KOTTC. Moreover, 460 genes were differentially expressed between the apex of KOTTC versus KOC (P<0.05) representing 37 pathways, including miR’s in cancer and cytokine signaling. The changes in miR expression in cancer may also denote changes associated with cell differentiation and apoptosis. These changes support our concept that regional, apex vs base, differences in vascular gene expression may underlie the basis of Takotsubo Syndrome.

MyomiRs in cultured muscle cells from patients with idiopathic inflammatory myopathy are modulated by disease but not by 6-month exercise training.

Idiopathic inflammatory myopathies/IIM are associated with changes in muscle-specific microRNA/miR. Exercise improves muscle function and metabolism in parallel with changes in miR expression. We investigated the effects of disease and exercise on miRs in differentiated muscle cells/myotubes from IIM patients and controls. Samples of m. vastus lateralis were obtained by needle biopsy from IIM patients before/after 6-month training and from matched sedentary healthy controls. Muscle cell cultures were established and exposed to saturated fatty acid during differentiation. MiR-133a,-133b,-206,-1 and their target genes (qPCR), fat oxidation (FOx), lipids (chromatography) and mitochondrial oxidative phosphorylation (OxPHOS) complexes (immunoblotting) were measured. Interrelations between in vitro miRs and metabolism of myotubes as well as clinical parameters and disease activity/MITAX were explored. Levels of miRs were higher in myotubes derived from IIM patients compared to healthy controls (up to 3.5-fold, p<0.05). Neither 6-month training (IIM patients) nor in vitro palmitate treatment modulated myomiRs in myotubes. However, miR-133a,-133b, and miR-1 correlated negatively with FOx (p<0.01), triacylglycerols (p<0.05) and OxPHOS complex-V (p<0.05) and positively with OxPHOS complex-I (p<0.05) in myotubes. MiR-133a and miR-133b in myotubes were related to disease activity and fasting glycaemia in vivo (both p<0.05). Upregulation of microRNAs involved in myogenesis and regeneration in muscle cells derived from IIM patients indicates activation of compensatory epigenetic mechanisms, potentially aimed to counteract disease progression. Relationships of microRNAs with in vitro metabolic profile of muscle cells as well as with clinical parameters support the role of muscle-specific microRNAs in modulating muscle metabolism and clinical state of patients.

Abstract 12403: Type 1 Diabetes Alters Estrogen-Stimulated microRNA Expression and Impairs Nitric Oxide Production in Human Coronary Artery Endothelial Cells

Introduction: Women developed CAD about 1 decade after men. This advantage is erased in T1DM women, and the mechanisms remain unclear. Estrogen (E2) stimulates endothelial NO production via estrogen receptors, and microRNA (miR) have emerged as critical regulators of endothelial function. Whether E2 stimulation of NO production is impaired in T1DM and whether E2 stimulates different miR expression patterns are unknown. Hypothesis: E2-stimulated NO production will be impaired in T1DM endothelial cells which will also express differences in miR expression with E2 exposure. Methods: All experiments were done with and without incubation with 1 nM 17β-estradiol for 24 hours. MicroRNA was isolated from culture human coronary artery endothelial cells (HCAECs) from a woman with and a woman without T1DM. MicroRNA was isolated from HCAECs with four different exposure conditions (T1DM ± 1 nM 17β-estradiol for 24 hr and non-T1DM± 1 nM 17β-estradiol for 24 hr, N=4 biological replicates for all exposures). Fold changes in expression comparing T1DM and non-T1DM cells with and without estradiol stimulation were generated at significance testing performed using DESeq2 with FDR set at 5%. NO production was measured in HCAECs under the same 4 conditions using DAF2-DA and HPLC. Results: 249 miRs were differentially expressed inT1DM HCAECs compared to non-T1DM HCAECs in non-E2 stimulated samples. In E2-stimulated samples, 201 miRs were differentially expressed. Cross-referencing these comparisons showed 16 miRs differentially expressed in T1DM HCAECs relative to non-T1DM HCAECs both with and without E2 stimulation. 4 of these (miRs 548-ar-3p, 625-3p, 369-3p, and 376a-5p) were significantly changed in the opposite direction with estrogen stimulation compared to unstimulated HCAECs, suggesting changes in the expression were due to changes in E2 signaling in T1DM HCAECs. Further, estradiol stimulation of T1DM HCAECS demonstrates a significantly blunted NO production compared to non-T1DM HCAECs (N=6, P&lt;0.05). Conclusions: E2-stimulated NO production is impaired and E2-stimulated changes in miR expression differ in the T1DM endothelium. Further work is necessary to determine whether these differences in miR expression impact E2-stimulated NO production in T1DM.

Vitamin C supplementation reduces expression of circulating miR-451a in subjects with poorly controlled type 2 diabetes mellitus and high oxidative stress.

BackgroundVitamin C is an essential element required for normal metabolic function. We investigated the effect of vitamin C supplementation on circulating miRNA (miR) expression in subjects with poorly controlled type 2 diabetes mellitus (T2DM). Changes in miR expression were also correlated with clinical measures of disease.MethodsPre- and post-vitamin C supplementation samples from five participants who had increased vitamin C levels, improved oxidative status and polymorphonuclear (PMN) function after receiving 1,000 mg of vitamin C daily for six weeks were screened for miRNA expression using the NanoString miRNA assay. Differences in miRNA expression identified from the miRNA screen were validated by qRT-PCR.ResultsFour miRNAs showed significantly different expression post-vitamin C supplementation relative to baseline, including the down-regulation of miR-451a (−1.72 fold change (FC), p = 0.036) and up-regulation of miR-1253 (0.62 FC, p = 0.027), miR-1290 (0.53 FC, p = 0.036) and miR-644a (0.5 FC, p = 0.042). The validation study showed only miR-451a expression was significantly different from baseline with vitamin C supplementation. MiR-451a expression was negatively correlated with vitamin C levels (r = − 0.497, p = 0.049) but positively correlated with levels of malondialdehyde (MDA) (r = 0.584, p = 0.017), cholesterol (r = 0.564, p = 0.022) and low-density lipoproteins (LDL) (r = 0.522, p = 0.037). Bioinformatics analysis of the putative target genes of miR-451a indicated gene functions related to signaling pathways involved in cellular processes, such as the mammalian target of rapamycin (mTOR) signaling pathway.ConclusionsVitamin C supplementation altered circulating miR-451a expression. The results from this pilot study suggest that miRNAs could be used as biomarkers to indicate oxidative status in subjects with T2DM and with poor glycemic control and could lead to a novel molecular strategy to reduce oxidative stress in T2DM.

Human Lungs Airway Epithelium Upregulate MicroRNA-17 and MicroRNA-548b in Response to Cold Ischemia and Ex Vivo Reperfusion.

Lung ischemia-reperfusion injury after transplantation is associated with worse clinical outcomes. MicroRNA (miR) are critical regulators of gene expression that could provide potential targets for novel gene therapy. Herein, we aim to examine the feasibility of using the ex vivo lung perfusion (EVLP) platform to examine the changes in miR expression in human lungs in response to cold ischemia and ex vivo reperfusion (CI/EVR). Twenty-four human lungs were perfused in cellular EVLP system for 2 h, and tissue samples were obtained before and after EVLP as well as from control donors. MicroRNA expression profiling of the lung tissue was performed using next-generation sequencing and downstream predicted target genes were examined. In situ hybridization assay of the validated miR was used to identify the expressing cell type. After 2 h of EVLP, cytokines production was significantly increased (IL-1β, IL-6, IL-8, IL-10, and TNF-α). MicroRNA sequencing identified a significant change in the expression of a total of 21 miR after CI and 47 miR after EVR. Validation using quantitative polymerase chain reaction showed significant upregulation of miR-17 and miR548b after CI/EVR. Downstream analysis identified abundant inflammatory and immunologic targets for miR-17 and miR-548b that are known mediators of lung injury. In situ hybridization assays detected positive signals of the 2 miR expression in alveolar epithelial cells. This study demonstrates the feasibility of using the EVLP platform to study miR signature in human lungs in response to CI/EVR. We found that miR-17 and miR-548b were upregulated in alveolar epithelial cells after CI/EVR, which merit further exploration.

Mechanosensitive MiRs regulated by anabolic and catabolic loading of human cartilage

Elucidation of whether miRs are involved in mechanotransduction pathways by which cartilage is maintained or disturbed has a particular importance in our understanding of osteoarthritis (OA) pathophysiology. The aim was to investigate whether mechanical loading influences global miR-expression in human chondrocytes and to identify mechanosensitive miRs responding to beneficial and non-beneficial loading regimes as potential to obtain valuable diagnostic or therapeutic targets to advance OA-treatment. Mature tissue-engineered human cartilage was subjected to two distinct loading regimes either stimulating or suppressing proteoglycan-synthesis, before global miR microarray analysis. Promising candidate miRs were selected, re-evaluated by qRT-PCR and tested for expression in human healthy vs OA cartilage samples. After anabolic loading, miR microarray profiling revealed minor changes in miR-expression while catabolic stimulation produced a significant regulation of 80 miRs with a clear separation of control and compressed samples by hierarchical clustering. Cross-testing of selected miRs revealed that miR-221, miR-6872-3p, miR-6723-5p were upregulated by both loading conditions while others (miR-199b-5p, miR-1229-5p, miR-1275, miR-4459, miR-6891-5p, miR-7150) responded specifically after catabolic loading. Mechanosensitivity of miR-221 correlated with pERK1/2-activation induced by both loading conditions. The miR-response to loading was transient and a constitutive deregulation of mechano-miRs in OA vs healthy articular cartilage was not observed. MiRs with broader vs narrower mechanosensitivity were discovered and the first group of mechanosensitive miRs characteristic for non-beneficial loading was defined that may shape the proteome differentially when cartilage tissue is disturbed. The findings prompt future investigations into miR-relevance for mechano-responsive pathways and the corresponding miR-target molecules.

Identification of a Novel microRNA Profile in Pediatric Cancer Patients Following Anthracycline Chemotherapy

Introduction Anthracycline chemotherapy (AC) can be associated with a progressive decline in left ventricular ejection fraction (LVEF), but the contributory mechanisms remain unclear. While changes in microRNAs (miRs), a key translational control point, have been identified in adult cardiovascular disease, whether and to what degree a shift in miR profiles occurs in pediatric AC patients has not been well studied. The goal of this study was to examine miR profiles (unbiased array) in pediatric AC patients compared to age matched referent normal patients. Hypothesis We hypothesize that pediatric AC patients will express a unique miR profile at initiation and completion of therapy and will be related to LVEF. Methods Serum was collected in pediatric patients (n=12, 13-22 years old) with newly diagnosed malignancy requiring AC within 24-48 hours following initiation of therapy (30-60 mg/m2) and approximately one year after completing maximal therapy. A custom microarray of 84 miRs associated with cardiovascular disease pathways was utilized (RT-qPCR) and indexed to referent normal profiles (n=17, 13-17 years old). LVEF was computed by cardiac MRI. Results LVEF fell from AC initiation at one year following AC (64.28% ± 1.78% vs 57.53% ± 0.95% respectively, p=0.004). Of the 84 miRs profiled, significant shifts in 17 miRs occurred relative to referent normal (p ≤ 0.05) where a nearly equivalent number were upregulated and downregulated (41 vs 59%, respectively). Moreover, the functional domain of miRs associated with myocardial differentiation and development fell by over 3-fold at completion of AC (Figure, p ≤ 0.05). Lastly, miRs-143-3p, -499a-5p, and -142-3p were associated with the fall in LVEF (p ≤ 0.05). Conclusions This study demonstrated for the first time that dynamic changes in miR expression occurs in pediatric cancer patients following AC. These findings suggest that miRs are a potential strategy for early identification of patients most susceptible to LV dysfunction following AC exposure, as well as potential targets for protective therapies.

PO-346 Defining microRNA mediated regulation of metabolic pathways involved in colon cancer progression (BST1-microRNA interactions)

IntroductionColorectal cancer (CRC) is the third most common cause of cancer related death in the world. Progressive accumulation of mutations in oncogenic and tumour suppressor pathways (e.g., KRAS and p53) and also microRNA (miR) deregulation are associated with CRC development. Very little has been done to dissect specific CRC pathways involved in miR regulation in response to stress and metabolic changes. Therefore, we previously characterised gene (mRNA) and miR expression as well as metabolic changes in different CRC genotypes. Here, we investigated the interaction between miR-mediated regulation of bone marrow stromal cell antigen 1 (BST1) or CD157, a metabolic gene involved in the conversion of nicotinamide adenine dinuclease (NAD) to paracrine factor cyclic ADP ribose (cADPR), following the acquisition of KRAS mutation in metastatic CRC.Material and methodsA combination of array analysis data, in-silico prediction tools and nuclear magnetic resonance (NMR) system were used to analyse gene and miR expression changes associated with different rounds of knock in/out mutations in Apc, Kras, and p53 CRC mouse models and their tumour-derived organoids (TDOs). Subsequently, we genetically modified human CRC cell lines and patients KRAS mutant (mut) TDOs from CRC metastases to modulate the candidate gene and miR. Organoids formation, growth rate and viability were measured with IncuCyte® Live-Cell Analysis System and Celigo® imaging cytometer.Results and discussionsWe identified mRNA/miR networks involved in cancer metabolic pathways and assessed miRs of potential interest among the candidates. MiR-203 appeared as one of the most significant candidates. Furthermore target validation and analysis of human tissues microarrays showed an association between KRAS mutations, miR-203 down-regulation and over-expression of BST1, which was identified as a direct target of miR-203 regulation in our studies. Repressing BST1 and over-expressing miR-203 had a significant effect on the proliferation and migration abilities of organoids in 3D culture in normal and calorie-deprived conditions.ConclusionThis project aimed at characterising the functional consequences of miR-203 loss and BST1 up regulation in normal and nutrient-deprived conditions in order to find a promising candidate as a therapeutic target in KRAS mut CRC. Although we showed KRAS mut CRC cells lost a growth advantage with miR-203 and BST1 deregulation ex vivo, work is on going to confirm the consequence of their interaction in vivo.

Lipoxin A4 stimulates endothelial miR-126-5p expression and its transfer via microvesicles.

The proresolution lipid mediator lipoxin (LX)A4 bestows protective bioactions on endothelial cells. We examined the impact of LXA4 on transcellular endothelial signaling via microRNA (miR)-containing microvesicles. We report LXA4 inhibition of MV release by TNF-α-treated HUVECs, associated with the down-regulation of 18 miR in endothelial microvesicles (EMVs) and the up-regulation of miR-126-5p, both in HUVECs and in EMVs. LXA4 up-regulated miR-126-5p by ∼5-fold in HUVECs and promoted a release of microvesicles (LXA4-EMVs) that enhanced miR-126-5p by ∼7-fold in recipient HUVECs. In these cells, LXA4-EMVs abrogated the up-regulation of VCAM-1, induced in recipient HUVECs by EMVs released by untreated or TNF-α-treated HUVECs. LXA4-EMVs also reduced by ∼40% the expression of SPRED1, which we validated as an miR-126-5p target, whereas they stimulated monolayer repair in an in vitro wound assay. This effect was lost when the EMVs were depleted of miR-126-5p. These results provide evidence that changes in miR expression and microvesicle packaging and transfer represent a mechanism of action of LXA4, which may be relevant in vascular biology and inflammation.-Codagnone, M., Recchiuti, A., Lanuti, P., Pierdomenico, A. M., Cianci, E., Patruno, S., Mari, V. C., Simiele, F., Di Tomo, P., Pandolfi, A., Romano, M. Lipoxin A4 stimulates endothelial miR-126-5p expression and its transfer via microvesicles.

Plasma MicroRNA Levels Following Resection of Metastatic Melanoma.

Melanoma remains the leading cause of skin cancer–related deaths. Surgical resection and adjuvant therapies can result in disease-free intervals for stage III and stage IV disease; however, recurrence is common. Understanding microRNA (miR) dynamics following surgical resection of melanomas is critical to accurately interpret miR changes suggestive of melanoma recurrence. Plasma of 6 patients with stage III (n = 2) and stage IV (n = 4) melanoma was evaluated using the NanoString platform to determine pre- and postsurgical miR expression profiles, enabling analysis of more than 800 miRs simultaneously in 12 samples. Principal component analysis detected underlying patterns of miR expression between pre- vs postsurgical patients. Group A contained 3 of 4 patients with stage IV disease (pre- and postsurgical samples) and 2 patients with stage III disease (postsurgical samples only). The corresponding preoperative samples to both individuals with stage III disease were contained in group B along with 1 individual with stage IV disease (pre- and postsurgical samples). Group A was distinguished from group B by statistically significant analysis of variance changes in miR expression (P < .0001). This analysis revealed that group A vs group B had downregulation of let-7b-5p, miR-520f, miR-720, miR-4454, miR-21-5p, miR-22-3p, miR-151a-3p, miR-378e, and miR-1283 and upregulation of miR-126-3p, miR-223-3p, miR-451a, let-7a-5p, let-7g-5p, miR-15b-5p, miR-16-5p, miR-20a-5p, miR-20b-5p, miR-23a-3p, miR-26a-5p, miR-106a-5p, miR-17-5p, miR-130a-3p, miR-142-3p, miR-150-5p, miR-191-5p, miR-199a-3p, miR-199b-3p, and miR-1976. Changes in miR expression were not readily evident in individuals with distant metastatic disease (stage IV) as these individuals may have prolonged inflammatory responses. Thus, inflammatory-driven miRs coinciding with tumor-derived miRs can blunt anticipated changes in expression profiles following surgical resection.

Network analysis of microRNA and mRNA seasonal dynamics in a highly plastic sensorimotor neural circuit.

BackgroundAdult neurogenesis and the incorporation of adult-born neurons into functional circuits requires precise spatiotemporal coordination across molecular networks regulating a wide array of processes, including cell proliferation, apoptosis, neurotrophin signaling, and electrical activity. MicroRNAs (miRs) - short, non-coding RNA sequences that alter gene expression by post-transcriptional inhibition or degradation of mRNA sequences - may be involved in the global coordination of such diverse biological processes. To test the hypothesis that miRs related to adult neurogenesis and related cellular processes are functionally regulated in the nuclei of the avian song control circuit, we used microarray analyses to quantify changes in expression of miRs and predicted target mRNAs in the telencephalic nuclei HVC, the robust nucleus of arcopallium (RA), and the basal ganglia homologue Area X in breeding and nonbreeding Gambel’s white-crowned sparrows (Zonotrichia leucophrys gambelli).ResultsWe identified 46 different miRs that were differentially expressed across seasons in the song nuclei. miR-132 and miR-210 showed the highest differential expression in HVC and Area X, respectively. Analyzing predicted mRNA targets of miR-132 identified 33 candidate target genes that regulate processes including cell cycle control, calcium signaling, and neuregulin signaling in HVC. Likewise, miR-210 was predicted to target 14 mRNAs differentially expressed across seasons that regulate serotonin, GABA, and dopamine receptor signaling and inflammation.ConclusionsOur results identify potential miR–mRNA regulatory networks related to adult neurogenesis and provide opportunities to discover novel genetic control of the diverse biological processes and factors related to the functional incorporation of new neurons to the adult brain.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-2175-z) contains supplementary material, which is available to authorized users.

Discordant Regulation of microRNA Between Multiple Experimental Models and Human Pulmonary Hypertension

The dysregulation of microRNA (miRNA) is known to contribute to the pathobiology of pulmonary arterial hypertension (PAH). However, the relationships between changes in tissue and circulating miRNA levels associated with different animal models and human pulmonary hypertension (PH) have not been defined. A set of miRNAs that have been causally implicated in PH, including miR-17, -21, -130b, -145, -204, -424, and -503, were measured by reverse transcription-quantitative polymerase chain reaction in the plasma, lung, and right ventricle of three of the most common rodent models of PH: the rat monocrotaline and SU5416 plus chronic hypoxia (SuHx) models and the mouse chronic hypoxia model. Plasma miRNA levels were also evaluated in a cohort of patients with PAH and healthy subjects. Several miRNA showed PH model-dependent perturbations in plasma and tissue levels; however, none of these were conserved across all three experimental models. Principle component analysis of miR expression changes in plasma revealed distinct clustering between rodent models, and SuHx-triggered PH showed the greatest similarity to human PAH. Changes in the plasma levels of several miRNA also correlated with changes in tissue expression. In particular, miR-424 was concordantly increased (1.3- to 1.5-fold, P < .05) in the plasma, lung, and right ventricle of hypoxic mice and in the plasma of patients with PAH. miRNAs with established etiologic roles in PH showed context-dependent changes in tissue and circulating levels, which were not consistent across rodent models and human PAH. This suggests different miRNA-dependent mechanisms may contribute to experimental and clinical PH, complicating potential diagnostic and therapeutic applications amenable to these miRNAs.

Exposure to diethylstilbestrol during pregnancy modulates microRNA expression profile in mothers and fetuses reflecting oncogenic and immunological changes.

Prenatal exposure to diethylstilbestrol (DES) is known to cause an increased susceptibility to a wide array of clinical disorders in humans. Previous studies from our laboratory demonstrated that prenatal exposure to DES induces thymic atrophy and apoptosis in the thymus. In the current study, we investigated if such effects on the thymus result from alterations in the expression of microRNA (miR). To that end, pregnant C57BL/6 mice who were exposed to DES and miR profiles in thymocytes of both the mother and fetuses on postnatal day 3 (gestation day 17) were studied. Of the 609 mouse miRs examined, we noted 59 altered miRs that were common for both mothers and fetuses, whereas 107 altered miRs were specific to mothers only and 101 altered miRs were specific to fetuses only. Upon further analyses in the fetuses, we observed that DES-mediated changes in miR expression may regulate genes involved in important functions, such as apoptosis, autophagy, toxicity, and cancer. Of the miRs that showed decreased expression following DES treatment, miR-18b and miR-23a were found to possess complementary sequences and binding affinity for 3' untranslated regions of the Fas ligand (FasL) and Fas, respectively. Transfection studies confirmed that DES-mediated downregulation of miR-18b and miR-23a led to increased FasL and Fas expression. These data demonstrated that prenatal DES exposure can cause alterations in miRs, leading to changes in the gene expression, specifically, miR-mediated increased expression in FasL and Fas causing apoptosis and thymic atrophy.

MicroRNA expression profiles in liver and colon of sexually immature gilts after exposure to Fusarium mycotoxins.

To improve our knowledge of the role of microRNAs (miRs) in responses of the porcine digestive system to two Fusarium mycotoxins, zearalenone (ZEN) and deoxynivalenol (DON), we examined the expression of 7 miRs (miR-9, miR-15a, miR-21, miR-34a, miR-122, miR-125b, and miR-192), previously found to be deregulated in diseased liver and colon cells. In this study, immature gilts were exposed to NOEL doses of ZEN (40 μg/kg/d), DON (12 μg/kg/d), ZEN + DON (40 + 12 μg/kg/d), andplacebo (negative control group) for 7, 14, 21, 28, 35, and 42 days. Before the treatment, expression levels of the selected miRs were measured in the liver, the duodenum, the jejunum, and the ascending and the descending colon of the gilts. Hierarchical clustering of the tissues by their miR expression profiles was consistent with what would be expected based on the anatomical locations and the physiological functions of the organs, suggesting that functions of the miRs are related to the specificities of the tissues in which they are expressed. A subset of 2 pairs of miRs (miR-21+miR-192 and miR-15a+miR-34a), which were assigned to two distinct clusters based on their tissue abundance, was then evaluated in the liver and the ascending and the descending colon during the treatment. The most meaningful results were obtained from the ascending colon, where a significant effect of the treatment was observed, suggesting that during the exposure to mycotoxins, the pathways involved in cell proliferation and survival were disordered. Changes in miR expression in the liver and the descending colon of the treated gilts were smaller, and were associated more with treatment duration than the exposure to ZEN, DON, or ZEN + DON. Further research should focus on identification of genes whose expression is regulated by these aberrantly expressed miRs. This should facili- tate understanding of the miRNA-regulated biological effects of mycotoxins.

MicroRNA expression profiling in a mouse model of oxygen-induced retinopathy

Objective To study morphological characteristics and microRNA (miR) expression profiling in a mouse model of oxygen-induced retinopathy (OIR). Methods Healthy C57BL/6J female mice and pups were randomly divided into normal and OIR group at postnatal day 7 (P7). The normal group was raised in a conventional cage and exposed to room air for 10 days. The OIR group was raised in a sealed chamber and exposed to (75±2)% oxygen. The moms were alternated between the two groups every day to promote their survival under hyperoxia. The OIR group was returned to the room air at P12. At P17, mice from either group were retro-orbitally injected with high molecular weight fluorescein isothiocyanate-dextran (FITC-dextran), the eye balls were fixed in 4% paraformaldehyde, and the retinal whole mounts were prepared. The retinal vessels labeled with FITC-dextran were observed under a fluorescence microscope; the eye balls were also processed for paraffin sections and Hematoxylin and Eosin (H&E) staining. The cell nucleus in the newly-formed vessels beyond the inner limiting membrane was quantified. The miR was extracted from the eyes, reverse transcribed, and subjected to a customized miR array analysis. The real-time PCR was preformed to verify the results of the miR array. Results Retinal whole mounts labeled with FITC-dextran showed that the peripheral retinal microvessels in the OIR group were tortuous, disorganized with neovascular buds, and the avascular area was prominent in central retina. In contrast, the vessels were smooth, organized, and evenly distributed in the retinas of normal group. The percentage of avascular area in total retina area in OIR group (25.81±2.12)% was 4-fold that in normal group (6.57±3.6)% (P<0.01, normal group vs OIR group). HE 4 miRs showed more than 3-fold expression changes, 3 were down-regulated and 1 was up-regulated. The expression of the 4 miRs was verified by real-time PCR. The expression trends of miR-3078, miR-140, miR-29b and miR-29c were consistent with those revealed by the miR array. MiR-3078 was significantly up-regulated (t=-2.380, P<0.05. normal group vs OIR group), and the other 3 miRs were significantly down-regulated (t=2.638, 2.323, 2.415, P<0.05. normal group vs OIR group). Conclusions The OIR mouse model has been established in our study. Differential expression of the microRNAs, including miR-3078, 140, 29b and 29c, was detected in normal and OIR mouse retinas. These miR expression changes may be associated with retinal neovascularization. These results would provide the new leads for further studying pathogenic mechanisms and therapeutic targets for neovascular retinopathy. Key words: Retinal diseases/etiology; MicroRNAs; Animal experimentation

MicroRNA and targeted mRNA expression profiling analysis in human colorectal adenomas and adenocarcinomas

BackgroundColorectal cancer (CRC) mainly develops from colorectal adenomas (CRAs). MicroRNAs (miRs) are short non-coding transcripts that regulate gene expression by binding to target mRNAs, preventing their expression. It was suggested that miRs were involved in cancer as tumour suppressors or oncogenes, thereby being also potential cancer biomarkers. We conducted an expression analysis of miRNAs and several of their target mRNAs, by using microarrays and quantitative Reverse Transcription-Polymerase Chain Reaction (RT-PCR) (RT-qPCR), in CRA and CRC, as compared to normal mucosa (NOR), in order to identify candidate miRNAs involved in CRC progression. ResultsMicroarray, together with confirmatory RT-qPCR analyses, showed 17 significantly deregulated miRNAs in colorectal lesions. While, as expected, some miRNAs have been previously reported to be associated with CRC, including miR-21 and miR-145, others were new (miR-125a-5p and miR-320 family). Some miRNAs were specific for the CRC versus NOR comparison (miR-320b), or for the CRA versus NOR comparison (miR-15b or miR-16), but several of them (miR-21, miR-24, miR-145, mir-150, miR-378) were deregulated in both CRAs and CRCs, as compared to NOR. The impact of these changes in miR expression on target genes is suggested by the associated deregulation of these genes in CRA and CRC. ConclusionsWe confirmed that several miRNAs were abnormally expressed in colorectal lesions, identified new deregulated miRs, and showed that several miRNAs could mark the transition from NOR to CRA, thereby marking progression from the early steps of cancer.

Abstract 12750: Atrial Tissue MicroRNAs 411-5p, 21-5p, 409-3p and 320a Are Associated With Atrial Fibrillation

Introduction: Atrial Fibrillation (AF) is the most common arrhythmia in clinical practice. MicroRNAs (miRs) are small RNAs that play a role in regulating cardiac remodeling and have been implicated in cardiac arrhythmogenesis. However, few studies have examined the association of atrial miR expression to AF. Hypothesis: Changes in miR expression (estimated as fold-difference in the delta cycle threshold compared to global mean) in human atria can be associated with AF. Methods: Thirty-one consecutive patients undergoing elective cardiac surgery were divided into 2 groups: those with history of AF (n=19) and those with no history of AF who stayed in sinus rhythm post-operatively (n=12). Atrial tissue samples were obtained from the right atrium in all but one (left atrium). Based on pilot data and prior literature, the expression of 82 miRs was assessed using high-throughput quantitative reverse-transcriptase polymerase chain reaction. We used logistic regression adjusting for age and sex to detect the associations between levels of atrial miRs and AF. Results: The mean age of the sample was 65 years (±13) and 71% were men. A history of coronary artery disease and heart failure was present in 42% and 36%, respectively. Among AF subjects, the age- and sex- adjusted odds ratios for the expression of miRs 411-5p, 21-5p, 409-3p and 320a were 0.08 (p= 0.02), 0.20 (p=0.02), 0.13 (p= 0.04) and 0.04 (p=0.048), respectively, compared to no AF. The fold-difference in atrial expression of miRs 411-5p, 21-5p, 409-3p and 320a were -0.567, -0.588, -0.375 and -0.427, respectively, in those with AF compared to no AF. Conclusion: In our study, the atrial expression of miRs 411, 21, 409 and 320 was lower in AF patients compared to those with no AF. Notably, these miRs regulate genes involved in atrial fibrosis, apoptosis, and ion channel function. Our findings further implicate miRs as important mediators of pathological atrial remodeling and suggest their usefulness as biomarkers in detecting AF.

Downregulation of miR-23a and miR-27a following experimental traumatic brain injury induces neuronal cell death through activation of proapoptotic Bcl-2 proteins.

MicroRNAs (miRs) are small noncoding RNAs that negatively regulate gene expression at the post-transcriptional level. To identify miRs that may regulate neuronal cell death after experimental traumatic brain injury (TBI), we profiled miR expression changes during the first several days after controlled cortical impact (CCI) in mice. miR-23a and miR-27a were rapidly downregulated in the injured cortex in the first hour after TBI. These changes coincided with increased expression of the proapoptotic Bcl-2 family members Noxa, Puma, and Bax. In an etoposide-induced in vitro model of apoptosis in primary cortical neurons, miR-23a and miR-27a were markedly downregulated as early as 1 h after exposure, before the upregulation of proapoptotic Bcl-2 family molecules. Administration of miR-23a and miR-27a mimics attenuated etoposide-induced changes in Noxa, Puma, and Bax, reduced downstream markers of caspase-dependent (cytochrome c release and caspase activation) and caspase-independent (apoptosis-inducing factor release) pathways, and limited neuronal cell death. In contrast, miRs hairpin inhibitors enhanced etoposide-induced neuronal apoptosis and caspase activation. Importantly, administration of miR-23a and miR-27a mimics significantly reduced activation of Puma, Noxa, and Bax as well as attenuated markers of caspase-dependent and -independent apoptosis after TBI. Furthermore, miR-23a and miR-27a mimics significantly attenuated cortical lesion volume and neuronal cell loss in the hippocampus after TBI. These findings indicate that post-traumatic decreases in miR-23a and miR-27a contribute to neuronal cell death after TBI by upregulating proapoptotic Bcl-2 family members, thus providing a novel therapeutic target.

Differential expression of stress and immune response pathway transcripts and miRNAs in normal human endothelial cells subjected to fractionated or single-dose radiation.

Although modern radiotherapy technologies can precisely deliver higher doses of radiation to tumors, thus, reducing overall radiation exposure to normal tissues, moderate dose, and normal tissue toxicity still remains a significant limitation. The present study profiled the global effects on transcript and miR expression in human coronary artery endothelial cells using single-dose irradiation (SD, 10 Gy) or multifractionated irradiation (MF, 2 Gy × 5) regimens. Longitudinal time points were collected after an SD or final dose of MF irradiation for analysis using Agilent Human Gene Expression and miRNA microarray platforms. Compared with SD, the exposure to MF resulted in robust transcript and miR expression changes in terms of the number and magnitude. For data analysis, statistically significant mRNAs (2-fold) and miRs (1.5-fold) were processed by Ingenuity Pathway Analysis to uncover miRs associated with target transcripts from several cellular pathways after irradiation. Interestingly, MF radiation induced a cohort of mRNAs and miRs that coordinate the induction of immune response pathway under tight regulation. In addition, mRNAs and miRs associated with DNA replication, recombination and repair, apoptosis, cardiovascular events, and angiogenesis were revealed. Radiation-induced alterations in stress and immune response genes in endothelial cells contribute to changes in normal tissue and tumor microenvironment, and affect the outcome of radiotherapy.