MicroRNA let-7e regulates the expression of caspase-3 during apoptosis of PC12 cells following anoxia/reoxygenation injury

Treatment of Rheumatoid Arthritis Based on the Inherent Bioactivity of Black Phosphorus Nanosheets

Rheumatoid arthritis (RA) is an autoimmune disease that affects the living quality of patients, especially the elderly population. RA-related morbidity and mortality increase significantly with age, while current clinical drugs for RA are far from satisfactory and may have serious side effects. Therefore, the development of new drugs with higher biosafety and efficacy is demanding. Black phosphorus nanosheets (BPNSs) have been widely studied because of their excellent biocompatibility. Here, we focus on the inherent bioactivity of BPNSs, report the potential of BPNSs as a therapeutic drug for RA and elucidate the underlying therapeutic mechanism. We find that BPNSs inhibit autophagy at an early stage via the AMPK-mTOR pathway, switch the energy metabolic pathway to oxidative phosphorylation, increase intracellular ATP levels, suppress apoptosis, reduce inflammation and oxidative stress, and down-regulate senescence-associated secretory phenotype (SASP)-related genes in rheumatoid arthritis synovial fibroblasts (RA-SFs). Further, BPNSs induce the apoptosis of macrophages and promote their transition from the M1 to the M2 phenotype by regulating related cytokines. Significantly, the administration of BPNSs can alleviate key pathological features of RA in mice, revealing great therapeutic potential. This study provides a novel option for treating RA, with BPNSs emerging as a promising therapeutic candidate.

A glimpse into let-7e roles in human disorders; friend or foe?

MicroRNAs (miRNAs) have been linked to abnormal expression and regulation in a number of diseases, including cancer. Recent studies have concentrated on miRNA Let-7e's significance in precision medicine for cancer screening and diagnosis as well as its prognostic and therapeutic potential. Differential let-7e levels in bodily fluids have the possibility to enable early detection of cancer utilizing less-invasive techniques, reducing biopsy-related risks. Although Let-7e miRNAs have been described as tumor suppressors, it is crucial to note that there exists proof to support their oncogenic activity in vitro and in in vivo. Let-7e's significance in chemo- and radiation treatment decisions has also been demonstrated. Let-7e can also prevent the synthesis of proinflammatory cytokines in a number of degenerative disorders, including musculoskeletal and neurological conditions. For the first time, an overview of the significance of let-7e in the prevention, detection, and therapy of cancer and other conditions has been given in the current review. Additionally, we focused on the specific molecular processes that underlie the actions of let-7e, more particularly, on malignant cells.

In diabetic male Wistar rats, quercetin-conjugated superparamagnetic iron oxide nanoparticles have an effect on the SIRT1/p66Shc-mediated pathway related to cognitive impairment

BACKGROUND

Quercetin (QC) possesses a variety of health-promoting effects in pure and in conjugation with nanoparticles. Since the mRNA-SIRT1/p66Shc pathway and microRNAs (miRNAs) are implicated in the oxidative process, we aimed to compare the effects of QC and QC-conjugated superparamagnetic iron oxide nanoparticles (QCSPIONs) on this pathway.

METHODS

Through the use of the chemical coprecipitation technique (CPT), SPIONs were synthesized, coated with dextran, and conjugated with quercetin. Adult male Wistar rats were given intraperitoneal injections of streptozotocin to look for signs of type 1 diabetes (T1D). The animals were randomized into five groups: the control group got deionized water (DI), free QC solution (25 mg/kg), SPIONs (25 mg/kg), and QCSPIONs (25 mg/kg), and all groups received repeat doses administered orally over 35 days. Real-time quantitative PCR was used to assess the levels of miR-34a, let-7a-p5, SIRT1, p66Shc, CASP3, and PARP1 expression in the hippocampus of diabetic rats.

RESULTS

In silico investigations identified p66Shc, CASP3, and PARP1 as targets of let-7a-5p and miR-34a as possible regulators of SIRT1 genes. The outcomes demonstrated that diabetes elevated miR-34a, p66Shc, CASP3, and PARP1 and downregulated let-7a-5p and SIRT1 expression. In contrast to the diabetic group, QCSPIONs boosted let-7a-5p expression levels and consequently lowered p66Shc, CASP3, and PARP1 expression levels. QCSPIONs also reduced miR-34a expression, which led to an upsurge in SIRT1 expression.

CONCLUSION

Our results suggest that QCSPIONs can regulate the SIRT1/p66Shc-mediated signaling pathway and can be considered a promising candidate for ameliorating the complications of diabetes.

Integrated transcriptome and miRNA sequencing analyses reveal that hypoxia stress induces immune and metabolic disorders in gill of genetically improved farmed tilapia (GIFT, Oreochromis niloticus)

The survival and growth of fish are significantly impacted by a hypoxic environment (low dissolved oxygen). In this study, we compared tissue structure, physiological changes, and mRNA/miRNA transcriptome, in gills of genetically improved farmed tilapia (GIFT, Oreochromis niloticus) between the hypoxic group (DO: 0.55 mg/L, HG) and the control group (DO: 5 mg/L, CG). The results showed that the gill filaments in the hypoxic group showed curling, engorgement, and apoptotic cells increased, and that exposure for 96 h resulted in a reduction in the antioxidant capacity. We constructed and sequenced miRNA and mRNA libraries from gill tissues of GIFT at 96 h of hypoxia stress. Between the HG and CG, a total of 14 differentially expressed (DE) miRNAs and 1557 DE genes were obtained. GO and KEGG enrichment showed that DE genes were mainly enriched in immune and metabolic pathways such as natural killer cell mediated cytotoxicity, steroid biosynthesis, primary immunodeficiency, and synthesis and degradation of ketone bodies. Based on the results of mRNA sequencing and screening for miRNA-mRNA pairs, we selected and verified six DE miRNAs and their probable target genes. The sequencing results were consistent with the qRT-PCR validation results. The result showed that under hypoxia stress, the innate immune response was up-regulated, and the adaptive immune response was down-regulated in the gill of GIFT. The synthesis of cholesterol in gill cells is reduced, which is conducive to the absorption of solvent oxygen. These findings offer fresh information about the processes of fish adaptation to hypoxic stress.

Identification of key potassium channel genes of temporal lobe epilepsy by bioinformatics analyses and experimental verification

One of the most prevalent types of epilepsy is temporal lobe epilepsy (TLE), which has unknown etiological factors and drug resistance. The detailed mechanisms underlying potassium channels in human TLE have not yet been elucidated. Hence, this study aimed to mine potassium channel genes linked to TLE using a bioinformatic approach. The results found that Four key TLE-related potassium channel genes (TERKPCGs) were identified: potassium voltage-gated channel subfamily E member (KCNA) 1, KCNA2, potassium inwardly rectifying channel, subfamily J, member 11 (KCNJ11), and KCNS1. A protein-protein interaction (PPI) network was constructed to analyze the relationship between TERKPCGs and other key module genes. The results of gene set enrichment analysis (GSEA) for a single gene indicated that the four TERKPCGs were highly linked to the cation channel, potassium channel, respiratory chain, and oxidative phosphorylation. The mRNA-TF network was established using four mRNAs and 113 predicted transcription factors. A ceRNA network containing seven miRNAs, two mRNAs, and 244 lncRNAs was constructed based on the TERKPCGs. Three common small-molecule drugs (enflurane, promethazine, and miconazole) target KCNA1, KCNA2, and KCNS1. Ten small-molecule drugs (glimepiride, diazoxide, levosimendan, and thiamylal et al.) were retrieved for KCNJ11. Compared to normal mice, the expression of KCNA1, KCNA2, KCNJ11, and KCNS1 was downregulated in the brain tissue of the epilepsy mouse model at both the transcriptional and translational levels, which was consistent with the trend of human data from the public database. The results indicated that key potassium channel genes linked to TLE were identified based on bioinformatics analysis to investigate the potential significance of potassium channel genes in the development and treatment of TLE.

Methionine Restriction Improves Cognitive Ability by Alleviating Hippocampal Neuronal Apoptosis through H19 in Middle-Aged Insulin-Resistant Mice

LncRNA H19 has been reported to regulate apoptosis and neurological diseases. Hippocampal neuron apoptosis damages cognitive ability. Methionine restriction (MR) can improve cognitive impairment. However, the effect of MR on hippocampal neuronal apoptosis induced by a high-fat diet (HFD) in middle-aged mice remains unclear. For 25 weeks, middle-aged mice (C57BL/6J) were given a control diet (CON, 0.86% methionine + 4.2% fat), a high-fat diet (HFD, 0.86% methionine + 24% fat), or an HFD + MR diet (HFMR, 0.17% methionine + 24% fat). The HT22 cells were used to establish the early apoptosis model induced by high glucose (HG). In vitro, the results showed that MR significantly improved cell viability, suppressed the generation of ROS, and rescued HT22 cell apoptosis in a gradient-dependent manner. In Vivo, MR inhibited the damage and apoptosis of hippocampal neurons caused by a high-fat diet, reduced hippocampal oxidative stress, improved hippocampal glucose metabolism, relieved insulin resistance, and enhanced cognitive ability. Furthermore, MR could inhibit the overexpression of H19 and caspase-3 induced by HFD, HG, or H2O2 in vivo and in vitro, and promoted let-7a, b, e expression. These results indicate that MR can protect neurons from HFD-, HG-, or H2O2-induced injury and apoptosis by inhibiting H19.

Micro RNAs as potential biomarkers in tuberculosis: A systematic review

Tuberculosis (TB) remains a major infectious disease across the globe. With increasing TB infections and a rise in multi-drug resistance, rapid diagnostic modalities are required to achieve TB control. Radiological investigations and microbiological tests (microscopic examination, cartridge-based nucleic acid amplification tests, and cultures) are most commonly used to diagnose TB. Histopathological/cytopathological examinations are also required for an accurate diagnosis in many patients. The causative agent, Mycobacterium tuberculosis (Mtb), is known to circumvent the host's immune system. Circulating microRNAs (miRNAs) play a crucial role in biological pathways and can be used as a potential biomarker to detect tuberculosis. miRNAs are small non-coding RNAs and negatively regulate gene expression during post-transcriptional regulation. The differential expression of miRNAs in multiple clinical samples in tuberculosis patients may be helpful as potential disease biomarkers. This review summarizes the literature on miRNAs in various clinical samples as biomarkers for TB diagnosis.

MicroRNA-204-5p regulates apoptosis by targeting Bcl2 in rat ovarian granulosa cells exposed to cadmium†

This study aimed to investigate whether cadmium (Cd) cytotoxicity in rat ovarian granulosa cells (OGCs) is mediated through apoptosis or autophagy and to determine the role of microRNAs (miRNAs) in Cd cytotoxicity. To test this hypothesis, rat OGCs were exposed to 0, 10, and 20 μM CdCl2 in vitro. As the Cd concentration increased, OGC apoptosis increased. In addition, Cd promoted apoptosis by decreasing the mRNA and protein expression levels of inhibition of B-cell lymphoma 2 (Bcl2). However, under our experimental conditions, no autophagic changes in rat OGCs were observed, and the mRNA and protein expression levels of the autophagic markers microtubule-associated protein 1 light chain 3 alpha (Map1lc3b) and Beclin1 (Becn1) were not changed. Microarray chip analysis, miRNA screening, and bioinformatics approaches were used to further explore the roles of apoptosis regulation-related miRNAs. In total, 19 miRNAs putatively related to Cd-induced apoptosis in rat OGCs were identified. Notably, miR-204-5p, which may target Bcl2, was identified. Then, rat OGCs were cultured in vitro and used to construct the miR-204-5p-knockdown cell line LV2-short hairpin RNA (shRNA). LV2-shRNA cells were exposed to 20 μM Cd for 12 h, and the mRNA and protein expression levels of Bcl2 were increased. Our findings suggest that Cd is cytotoxic to rat OGCs, and mitochondrial apoptosis rather than autophagy mediates Cd-induced damage to OGCs. Cd also affects apoptosis-related miRNAs, and the underlying apoptotic mechanism may involve the Bcl2 gene.

Circulating microRNA let‑7e is decreased in knee osteoarthritis, accompanied by elevated apoptosis and reduced autophagy

Knee osteoarthritis (KOA) is a major cause of leg disability in the elderly population. Recently, the expression levels of circulating microRNA (miRNA) let-7e have been reported to be significantly reduced in KOA. The aims of the present study were to assess the feasibility of let-7e as a serum marker for detecting KOA and to explore the underlying mechanisms of its involvement. Based on previous studies and bioinformatics analysis, let-7e may regulate apoptosis and autophagy of articular chondrocytes. A total of 10 patients with KOA and 10 patients with trauma without KOA were recruited to examine the levels of let-7e in peripheral blood. Subsequently, KOA rat models were established, and the levels of let-7e in the cartilage and serum were examined, the expression of apoptotic proteins and autophagy-related proteins in the cartilage were investigated, and apoptotic and autophagic activities of primary cultured chondrocytes were also detected. In patients with KOA, let-7e levels in the peripheral serum were significantly decreased compared with the control group, and this result was confirmed in the peripheral serum and cartilage of KOA rats. In addition, the expression levels of proteins involved in the apoptotic pathway were increased in the cartilage of KOA rats, and apoptotic activity was increased. The expression of autophagy-related proteins beclin 1 and microtubule associated protein 1 light chain 3 β (LC3B) II/LC3BI in the articular cartilage of KOA rats was lower compared with the controls, and autophagy was decreased. Si-Miao-San (SMS) treatment restored the expression of let-7e and reversed the changes in apoptosis and autophagy. Therefore, the present study provided additional evidence that circulating let-7e may be a potential serum biomarker for the diagnosis and treatment of KOA. Elevated apoptosis levels and decreased autophagy levels of cartilage tissue are involved in KOA, and treatment with SMS may reverse these effects.

Extracellular Vesicles Derived from Wharton's Jelly Mesenchymal Stem Cells Prevent and Resolve Programmed Cell Death Mediated by Perinatal Hypoxia-Ischemia in Neuronal Cells

Hypoxic-ischemic (HI) insult in the perinatal phase harbors a high risk of encephalopathy in the neonate. Brain cells undergo apoptosis, initiating neurodegeneration. So far, therapeutic approaches such as cooling remain limited. Transplantation of mesenchymal stem cells (MSCs) exhibits therapeutic success despite the short-time survival in the host brain, providing strong evidence that their beneficial effects are largely based on secreted factors, including extracellular vesicles (EVs). The aim of this study was to investigate the effects of human Wharton’s jelly MSC (hWJ-MSC)-derived EVs on neuroprotection and neuroregeneration, using an in vitro model of oxygen–glucose deprivation/reoxygenation (OGD/R) mimicking HI injury in the mouse neuroblastoma cell line neuro2a (N2a). hWJ-MSC-derived EVs were isolated from cell culture supernatants by multistep centrifugation and identified by endosomal marker expression and electron microscopy. OGD/R significantly increased DNA fragmentation and caspase 3 (Casp3) transcription in N2a cells relative to undamaged cells. OGD/R-mediated DNA fragmentation and Casp3 expression could be prevented as well as resolved by the addition of hWJ-MSC-derived EV before and after OGD, respectively. hWJ-MSC-derived EV also tended to increase the phosphorylation of the B cell lymphoma 2 (Bcl2) family member Bcl-2-antagonist of cell death (BAD) in N2a cells, when added prior or post OGD, thereby inactivating the proapoptotic function of BAD. Fluorescence confocal microscopy revealed the close localization of hWJ-MSC-derived EVs to the nuclei of N2a cells. Furthermore, EVs released their RNA content into the cells. The expression levels of the microRNAs (miRs) let-7a and let-7e, known regulators of Casp3, were inversely correlated to Casp3. Our data suggest that hWJ-MSC-derived EVs have the potential to prevent and resolve HI-induced apoptosis in neuronal cells in the immature neonatal brain. Their antiapoptotic effect seems to be mediated by the transfer of EV-derived let-7-5p miR.

LPS expands MDSCs by inhibiting apoptosis through the regulation of the GATA2/let-7e axis

Myeloid-derived suppressor cells (MDSCs) represent a group of immature myeloid cells composed of myeloid progenitor cells and immature myeloid cells that can negatively regulate immune responses by inhibiting T-cell function. In mice, MDSCs are broadly defined by the expression of CD11b and Gr1. We and others have shown that injection of a lethal or sublethal dose of lipopolysaccharide (LPS) into mice could result in the expansion of MDSCs in the bone marrow (BM), spleen and blood. Until now, the molecular mechanisms responsible for this expansion are poorly studied; specifically, the roles of the individual microRNAs (miRNAs) which may be involved remain largely unknown. We performed microarray analysis to compare the miRNA expression profiles of CD11b⁺ Gr1⁺ cells sorted from the BM of LPS-injected and phosphate-buffered saline-injected mice. We identified let-7e, which was highly upregulated in the LPS-treated group, as a potent regulator of LPS-induced MDSC expansion. Furthermore, let-7e overexpression in BM chimeric mice led to a noticeable increase in the population of CD11b⁺ Gr1⁺ cells, which resulted from reduced cellular apoptosis. Further studies showed that let-7e could directly target caspase-3 to inhibit cell apoptosis, and upregulation of let-7e in LPS-stimulated MDSCs could be due to the relieved repression of let-7e transcription exerted by downregulated GATA2. Our findings suggest that LPS expands MDSCs by inhibiting apoptosis through the regulation of the GATA2/let-7e axis.

Identification of Blood Let-7e-5p as a Biomarker for Ischemic Stroke

Circulating microRNAs (miRNAs) are emerging as novel disease biomarkers. Using a miRNA microarray, we previously showed that the whole blood level of let-7e-5p was significantly higher in ischemic stroke patients than in control subjects. However, the association between let-7e-5p expression and the occurrence of ischemic stroke remains unknown. In this study, we validated the expression levels of let-7e-5p in two case-control populations using miRNA TaqMan assays and further investigated the potential targets of let-7e-5p. The results suggest that the blood level of let-7e-5p was significantly higher in patients with ischemic stroke than in controls (p<0.05). Higher levels of let-7e-5p were associated with increased occurrence of ischemic stroke (adjusted OR, 1.89; 95% CI, 1.61~2.21, p<0.001) in the combined population. The addition of let-7e-5p to traditional risk factors led to an improvement in the area under the curve, which increased from 0.74 (95% CI, 0.70~0.78) to 0.82 (95% CI, 0.78~0.85), with a net reclassification improvement of 16.76% (p<0.0001) and an integrated discrimination improvement of 0.10 (p<0.0001) for patients with ischemic stroke. Bioinformatics prediction and cell experiments suggested that the expression levels of four genes enriched in the MAPK signaling pathway were down-regulated by let-7e-5p transfection. Specifically, the expression levels of the genes CASP3 and NLK were significantly lower in ischemic stroke patients than in controls and were negatively correlated with let-7e-5p expression. In summary, our study suggests the potential use of blood let-7e-5p as a biomarker for ischemic stroke and indicates its involvement in the related pathomechanism.

let-7b suppresses apoptosis and autophagy of human mesenchymal stem cells transplanted into ischemia/reperfusion injured heart 7by targeting caspase-3

Introduction

Mesenchymal stem cells (MSCs) have therapeutic potential for the repair of myocardial injury. The efficacy of MSC therapy for myocardial regeneration mainly depends on the survival of cells after transplantation into the infarcted heart. In the transplanted regions, reactive oxygen species (ROS) can cause cell death, and this process depends on caspase activation and autophagosome formation.

Methods

A Software TargetScan was utilized to search for microRNAs (miRNAs) that target caspase-3 mRNA. Six candidate miRNAs including let-7b were selected and transfected into human MSCs in vitro. Expression of MEK-EKR signal pathways and autophagy-related genes were detected. Using ischemia/reperfusion model (I/R), the effect of MSCs enriched with let-7b was determined after transplantation into infarcted heart area. Miller catheter was used to evaluate cardiac function.

Results

Here, we report that let-7b targets caspase-3 to regulate apoptosis and autophagy in MSCs exposed to ROS. Let-7b-transfected MSCs (let-7b-MSCs) showed high expression of survival-related proteins, including p-MEK, p-ERK and Bcl-2, leading to a decrease in Annexin V/PI- and TUNEL-positive cells under ROS-rich conditions. Moreover, autophagy-related genes, including Atg5, Atg7, Atg12 and beclin-1, were significantly downregulated in let-7b-MSCs. Using a rat model of acute myocardial infarction, we found that intramyocardial injection of let-7b-MSCs markedly enhanced left ventricular (LV) function and microvessel density, in accordance with a reduced infarct size and the expression of caspase-3.

Conclusions

Taken together, these data indicate that let-7b may protect MSCs implanted into infarcted myocardium from apoptosis and autophagy by directly targeting caspase-3 signaling.

Heterogeneity and individuality: microRNAs in mental disorders

MicroRNAs are about 22 nucleotide long single-stranded RNA molecules, negatively regulating gene expression of a single gene or a gene network. In neural tissues, they have been implicated in developmental and neuroplasticity-related processes, such as neurogenesis, differentiation, apoptosis and long-term potentiation. Their molecular mode of action is reminiscent of findings of genome-wide association studies in mental disorders, unable to attribute the risk of disease to a specific gene, but rather to multiple genes, gene-networks and gene-environment interaction. As such, microRNAs are an attractive target for research. Here, we review clinical studies conducted in humans on microRNAs in mental disorders with a particular focus on schizophrenia, bipolar disorder, major depressive disorder and anxiety disorders. The majority of clinical studies have focused on schizophrenia. The most robust finding has been reported for rs1625579 located in MIR137HG, which was associated with schizophrenia on a genome-wide level. Concerning bipolar disorder, major depression and anxiety disorders, promising results have been published, but only a considerably smaller number of clinical studies is available and genome-wide association studies did not suggest a direct link to microRNAs so far. Expression of microRNAs as biomarkers of mental disorders and treatment response is currently emerging with preliminary results. Larger-scaled genetic and functional studies along with translational research are needed to enhance our understanding of microRNAs in mental disorders. These studies will aid in disentangling the complex genetic nature of these disorders and possibly contribute to the development of novel, individualized diagnostic and therapeutic approaches.

Hsa-let-7g miRNA targets caspase-3 and inhibits the apoptosis induced by ox-LDL in endothelial cells

It has been well confirmed ox-LDL plays key roles in the development of atherosclerosis via binding to LOX-1 and inducing apoptosis in vascular endothelial cells. Recent studies have shown ox-LDL can suppress microRNA has-let-7g, which in turn inhibits the ox-LDL induced apoptosis. However, details need to be uncovered. To determine the anti-atherosclerosis effect of microRNA has-let-7g, and to evaluate the possibility of CASP3 as an anti-atherosclerotic drug target by has-let-7g, the present study determined the role of hsa-let-7g miRNA in ox-LDL induced apoptosis in the vascular endothelial cells. We found that miRNA has-let-7g was suppressed during the ox-LDL-induced apoptosis in EAhy926 endothelial cells. In addition, overexpression of has-let-7g negatively regulated apoptosis in the endothelial cells by targeting caspase-3 expression. Therefore, miRNA let-7g may play important role in endothelial apoptosis and atherosclerosis.

MicroRNA changes associated with atypical CYP1A1 inducer BMS-764459

The corticotrophin releasing factor (CRF) receptor I antagonist, BMS-764459 (evaluated as a potential treatment of affective disorders), was orally dosed to female Sprague-Dawley rats once daily for 2 weeks (vehicle control or 175mg/kg/day). To investigate the mechanism of BMS-764459-related liver weight increases, total liver RNA was isolated and evaluated for mRNA gene expression by microarray analysis (assessing the expression of approximately 24,000 genes) from snap-frozen tissue. Subsequently, mRNA and miRNA (microRNA) were also analyzed 5 years later from FFPE (Formalin Fixed Paraffin Embedded) samples via RT-PCR (about 800 miRNA evaluated). Genomic analyses showed that BMS-764459 induces AhR target genes with additional inductions of CYP2B, CYP3A, and Abcc3 consistent with the gene expression pattern of atypical CYP1A1 inducers. Analysis of miRNA expression identified a number of significantly affected miRNAs. To further evaluate their role in atypical CYP1A1 induction, an in silico evaluation of differentially expressed miRNA was performed and their putative mRNA 3'-UTR (untranslated region) binding sequences were evaluated. MiR-680 and miR-29a were identified as potential regulators and biomarkers of atypical CYP1A1 induction by regulating Abcc3, CYP3A and CYP2B as well as a number of AhR targeted genes.

MicroRNA let-7e is associated with the pathogenesis of experimental autoimmune encephalomyelitis

MicroRNAs (miRNAs) play important roles in the regulation of immune responses. There is evidence that miRNAs also participate in the pathogenesis of multiple sclerosis (MS), but how the miRNAs regulate the pathogenesis of MS is still under investigation. The identification of new members of the miRNA family associated with the pathogenesis of MS could facilitate early diagnosis and treatment. Here, we show that the level of miRNA let-7e is significantly upregulated in EAE, an animal model of MS using miRNA array and quantitative real-time PCR. The expression of let-7e was mainly in CD4(+) T cells and infiltrated mononuclear cells of CNS, and highly correlated with the development of EAE. We found that let-7e silencing in vivo inhibited encephalitogenic Th1 and Th17 cells and attenuated EAE, with reciprocal increase of Th2 cells; overexpression of let-7e enhanced Th1 and Th17 cells and aggravated EAE. We also identified IL-10 as one of the functional targets of let-7e. Together, we propose that let-7e is a new miRNA involved in the regulation of encephalitogenic T-cell differentiation and the pathogenesis of EAE.

Contribution of microRNA-203 to the isoflurane preconditioning-induced neuroprotection

A prior exposure to isoflurane, a common volatile anesthetic, provides neuroprotection (isoflurane preconditioning). To determine the role of microRNAs in this protection, we performed microRNA array assay on cerebral cortex harvested from rats exposed to isoflurane or isoflurane-exposed rat B35 neuron-like cells. We showed that isoflurane significantly increased microRNA-203 expression in B35 neuron-like cells. The microRNA-203 expression in rat cerebral cortex also trended to increase after isoflurane exposure. Over-expression of microRNA-203 increased the tolerance of B35 cells to oxygen-glucose deprivation and the expression of phospho-Akt, a protein kinase that promotes cell survival. Isoflurane preconditioning also reduced the injury of these cells after oxygen-glucose deprivation. These results suggest that isoflurane preconditioning-induced neuroprotection may involve increased expression of microRNA-203. This finding provides the initial evidence that micoRNA-203 is a target for isoflurane in the brain.

Identification of miRNAs in C. roseus and their potential targets

MicroRNAs are small (20-22 nucleotides) none coding, regulatory RNAs, whose pivotal role in gene expression has been associated in number of diseases, therefore prediction of miRNA is an essential yet challenging field. In this study miRNAs of C. roseus are predicted along with their possible target genes. A total of 19,899 ESTs were downloaded from dbEST database and processed and trimmed through SeqClean. Nine sequences were trashed and 31 sequences were trimmed by the program and the resulting sequences were submitted to Repeatmasker and TGICL for clustering and assembly. This contig database was now used to find the putative miRNAs by performing a local BLAST with the miRNAs of B. rapa retrieved from miRBase. The targets were scanned by hybridizing screened ESTs with the UTRs of human using miRanda software. Finally, 7 putative miRNAs were found to hybridize with the various targets of signal transduction and apoptosis that may play significant role in preventing diseases like Leukemia, Arthritis and Alzheimer.