Nóra Faragó

MicroRNAs associated with ischemia-reperfusion injury and cardioprotection by ischemic pre- and postconditioning: protectomiRs

We aimed to characterize early changes in microRNA expression in acute cardioprotection by ischemic pre- and postconditioning in rat hearts. Hearts isolated from male Wistar rats were subjected to 1) time-matched nonischemic perfusion, 2) ischemia-reperfusion (30 min of coronary occlusion and 120 min of reperfusion), 3) preconditioning (3 × 5 min of coronary occlusion) followed by ischemia-reperfusion, or 4) ischemia-reperfusion with postconditioning (6 × 10 s of global ischemia-reperfusion at the onset of reperfusion). Infarct size was significantly reduced by both interventions. Of 350 different microRNAs assessed by microarray analysis, 147-160 microRNAs showed detectable expression levels. Compared with microRNA alterations induced by ischemia-reperfusion versus time-matched nonischemic controls, five microRNAs were significantly affected by both pre- and postconditioning (microRNA-125b*, microRNA-139-3p, microRNA-320, microRNA-532-3p, and microRNA-188), four microRNAs were significantly affected by preconditioning (microRNA-487b, microRNA-139-5p, microRNA-192, and microRNA-212), and nine microRNAs were significantly affected by postconditioning (microRNA-1, microRNA let-7i, microRNA let-7e, microRNA let-7b, microRNA-181a, microRNA-208, microRNA-328, microRNA-335, and microRNA-503). Expression of randomly selected microRNAs was validated by quantitative real-time PCR. By a systematic comparison of the direction of microRNA expression changes in all groups, we identified microRNAs, specific mimics, or antagomiRs that may have pre- and postconditioning-like cardioprotective effects (protectomiRs). Transfection of selected protectomiRs (mimics of microRNA-139-5p, microRNA-125b*, microRNA let-7b, and inhibitor of microRNA-487b) into cardiac myocytes subjected to simulated ischemia-reperfusion showed a significant cytoprotective effect. This is the first demonstration that the ischemia-reperfusion-induced microRNA expression profile is significantly influenced by both pre- and postconditioning, which shows the involvement of microRNAs in cardioprotective signaling. Moreover, by analysis of microRNA expression patterns in cardioprotection by pre- and postconditioning, specific protectomiRs can be revealed as potential therapeutic tools for the treatment of ischemia-reperfusion injury.

MicroRNA profile of polyunsaturated fatty acid treated glioma cells reveal apoptosis-specific expression changes

BackgroundPolyunsaturated fatty acids (PUFAs) such as γ-linolenic acid (GLA), arachidonic acid (AA) and docosahexaenoic acid (DHA) have cytotoxic action on glioma cells.ResultsWe evaluated the cytotoxic action of GLA, AA and DHA on glioma cells with specific reference to the expression of miRNAs. Relative expression of miRNAs were assessed by using high throughput nanocapillary real-time PCR. Most of the miRNA target genes that showed altered expression could be classified as apoptotic genes and were up-regulated by PUFA or temozolomide treatment, while similar treatments resulted in repression of the corresponding mRNAs, such as cox2, irs1, irs2, ccnd1, itgb3, bcl2, sirt1, tp53inp1 and k-ras.ConclusionsOur results highlight involvement of miRNAs in the induction of apoptosis in glioma cells by fatty acids and temozolomide.

GABAergic Neurogliaform Cells Represent Local Sources of Insulin in the Cerebral Cortex

Concentrations of insulin in the brain are severalfold higher than blood plasma levels. Insulin in the brain regulates the metabolism, molecular composition, and cognitive performance of microcircuits and reduces food intake; cerebral insulin levels are altered in diabetes, aging, obesity, and Alzheimers disease. Released by pancreatic β cells, insulin passes the blood–brain barrier, but sources of locally released insulin still remain unclear. We find that insulin is strongly expressed in GABAergic neurogliaform cells in the cerebral cortex of the rat detected by single-cell digital PCR. Focal application of glucose or glibenclamide to neurogliaform cells mimics the excitation suppressing effect of external insulin on local microcircuits via insulin receptors. Thus, neurogliaform cells might link GABAergic and insulinergic action in cortical microcircuits.

High-Density Real-Time PCR-Based in Vivo Toxicogenomic Screen to Predict Organ-Specific Toxicity

Toxicogenomics, based on the temporal effects of drugs on gene expression, is able to predict toxic effects earlier than traditional technologies by analyzing changes in genomic biomarkers that could precede subsequent protein translation and initiation of histological organ damage. In the present study our objective was to extend in vivo toxicogenomic screening from analyzing one or a few tissues to multiple organs, including heart, kidney, brain, liver and spleen. Nanocapillary quantitative real-time PCR (QRT-PCR) was used in the study, due to its higher throughput, sensitivity and reproducibility, and larger dynamic range compared to DNA microarray technologies. Based on previous data, 56 gene markers were selected coding for proteins with different functions, such as proteins for acute phase response, inflammation, oxidative stress, metabolic processes, heat-shock response, cell cycle/apoptosis regulation and enzymes which are involved in detoxification. Some of the marker genes are specific to certain organs, and some of them are general indicators of toxicity in multiple organs. Utility of the nanocapillary QRT-PCR platform was demonstrated by screening different references, as well as discovery of drug-like compounds for their gene expression profiles in different organs of treated mice in an acute experiment. For each compound, 896 QRT-PCR were done: four organs were used from each of the treated four animals to monitor the relative expression of 56 genes. Based on expression data of the discovery gene set of toxicology biomarkers the cardio- and nephrotoxicity of doxorubicin and sulfasalazin, the hepato- and nephrotoxicity of rotenone, dihydrocoumarin and aniline, and the liver toxicity of 2,4-diaminotoluene could be confirmed. The acute heart and kidney toxicity of the active metabolite SN-38 from its less toxic prodrug, irinotecan could be differentiated, and two novel gene markers for hormone replacement therapy were identified, namely fabp4 and pparg, which were down-regulated by estradiol treatment.

Digital PCR to determine the number of transcripts from single neurons after patch-clamp recording.

Whole-cell patch-clamp recording enables detection of electrophysiological signals from single neurons as well as harvesting of perisomatic RNA through the patch pipette for subsequent gene expression analysis. Amplification and profiling of RNA with traditional quantitative real-time PCR (qRT-PCR) do not provide exact quantitation due to experimental variation caused by the limited amount of nucleic acid in a single cell. Here we describe a protocol for quantifying mRNA or miRNA expression in individual neurons after patch-clamp recording using high-density nanocapillary digital PCR (dPCR). Expression of a known cell-type dependent marker gene (gabrd), as well as oxidative-stress related induction of hspb1 and hmox1 expression, was quantified in individual neurogliaform and pyramidal cells, respectively. The miRNA mir-132, which plays a role in neurodevelopment, was found to be equally expressed in three different types of neurons. The accuracy and sensitivity of this method were further validated using synthetic spike-in templates and by detecting genes with very low levels of expression.

Gene and protein expression changes in response to normoxic perfusion in mouse hearts

INTRODUCTION Although crystalloid-perfused isolated heart models are widely used in cardiovascular research, there are several limitations of these techniques. Changes in cardiac gene expression pattern due to normoxic perfusion itself have not been studied, despite its potential importance to provide useful information on limitations of this model. Therefore, here we investigated the time-dependent effect of normoxic, normothermic perfusion on global gene expression at mRNA and protein levels. METHODS Hearts from male CFLP mice were perfused according to the Langendorff technique. We assessed relative gene expression changes by DNA microarray analysis of 8000 genes after 0, 60 and 120 min perfusion. RESULTS Twelve genes exhibited significant up-regulation and 27 showed repression in hearts perfused for 60 or 120 min as compared to 0 min controls. Expression changes of 17 selected genes were verified and an additional 19 genes were examined by real-time quantitative PCR. Genes with altered expression included those coding for Creatin kinase, Lactate dehydrogenase, Voltage-dependent anion channel 1, a Disintegrin and Metalloprotease domain 3, Integrin alpha 7, Long-chain acyl-CoA dehydrogenase, Casein kinase II, Ketohexokinase, Chloride ion current inducer protein, Matrix metalloproteinase 2 and 9, Superoxide dismutases and Nitric oxide synthases, etc. DISCUSSION Our results show that normoxic crystalloid perfusion itself results in time-dependent changes in cardiac gene expression which should be considered when designing ex vivo perfusion protocols in the mouse heart to mimic cardiac pathologies as many of these genes have been suspected to influence several cardiovascular diseases.

The Curcumin Analog C-150, Influencing NF-κB, UPR and Akt/Notch Pathways Has Potent Anticancer Activity In Vitro and In Vivo

C-150 a Mannich-type curcumin derivative, exhibited pronounced cytotoxic effects against eight glioma cell lines at micromolar concentrations. Inhibition of cell proliferation by C-150 was mediated by affecting multiple targets as confirmed at transcription and protein level. C-150 effectively reduced the transcription activation of NFkB, inhibited PKC-alpha which are constitutively over-expressed in glioblastoma. The effects of C-150 on the Akt/ Notch signaling were also demonstrated in a Drosophila tumorigenesis model. C-150 reduced the number of tumors in Drosophila with similar efficacy to mitoxantrone. In an in vivo orthotopic glioma model, C-150 significantly increased the median survival of treated nude rats compared to control animals. The multi-target action of C-150, and its preliminary in vivo efficacy would render this curcumin analogue as a potent clinical candidate against glioblastoma.

Purification of high-quality micro RNA from the heart tissue

Micro RNAs (miRNA) are an abundant class of small RNAs that regulate the stability and translation of cognate mRNAs. MiRNAs are potential diagnostic markers, moreover, they play an essential role in the development of various heart disesases. In case of limited tissue material, such as, e.g. human biopsies, purification of miRNAs with sufficient yield is critical. Reproducible expression analysis of miRNAs is highly dependent on the quality of the RNA, which is often difficult to achieve from fibrous tissue such as the heart. Several companies developed general purification kits for miRNAs, however, none of them are specialized to fibrotic tissues. Here we describe an optimized miRNA purification protocol that results in high miRNA yield as compared to other methods including trizol-based and column-based protocols. By using our improved protocol, miRNA obtained from heart tissue gave more reproducible results in QRT-PCR analysis and obtained more significant calls (172 vs. 118) during DNA microarray analysis when compared to the commercially available kit. In addition to the heart tissue, the present protocol can be applied to other fibrotic tissues, such as lung or skeletal muscle to isolate high-purity miRNA.

Mannich Curcuminoids as Potent Anticancer Agents

A series of novel curcuminoids were synthesised for the first time via a Mannich‐3CR/organocatalysed Claisen–Schmidt condensation sequence. Structure–activity relationship (SAR) studies were performed by applying viability assays and holographic microscopic imaging to these curcumin analogues for anti‐proliferative activity against A549 and H1975 lung adenocarcinoma cells. The TNFα‐induced NF‐κB inhibition and autophagy induction effects correlated strongly with the cytotoxic potential of the analogues. Significant inhibition of tumour growth was observed when the most potent analogue 44 was added in liposomes at one‐sixth of the maximally tolerated dose in the A549 xenograft model. The novel spectrum of activity of these Mannich curcuminoids warrants further preclinical investigations.

Intelligent image-based in situ single-cell isolation

Quantifying heterogeneities within cell populations is important for many fields including cancer research and neurobiology; however, techniques to isolate individual cells are limited. Here, we describe a high-throughput, non-disruptive, and cost-effective isolation method that is capable of capturing individually targeted cells using widely available techniques. Using high-resolution microscopy, laser microcapture microscopy, image analysis, and machine learning, our technology enables scalable molecular genetic analysis of single cells, targetable by morphology or location within the sample.The isolation of single cells while retaining context is important for quantifying cellular heterogeneity but technically challenging. Here, the authors develop a high-throughput, scalable workflow for microscopy-based single cell isolation using machine-learning, high-throughput microscopy and laser capture microdissection.