MicroRNA-124 and -137 cooperativity controls caspase-3 activity through BCL2L13 in hippocampal neural stem cells

A Standardized Protocol for Stereotaxic Intrahippocampal Administration of Kainic Acid Combined with Electroencephalographic Seizure Monitoring in Mice

Lack of scientific reproducibility is a growing concern and weak experimental practices may contribute to irreproducibility. Here, we describe an optimized and versatile protocol for stereotaxic intrahippocampal administration of Kainic Acid (KA) in mice with a C57Bl6 background. In this protocol, KA administration is combined with in vivo recording of neuronal activity with wired and wireless setups. Following our protocol, KA administration results in a robust dose-dependent induction of low-level epileptiform activity or Status Epilepticus (SE) and induces previously characterized hallmarks of seizure-associated pathology. The procedure consists of three main steps: Craniotomy, stereotaxic administration of KA, and placement of recording electrodes in intrahippocampal, and subdural locations. This protocol offers extended possibilities compared to the systemic administration of KA, as it allows the researcher to accurately regulate the local dose of KA and resulting seizure activity, and permits the use and study of convulsive and non-convulsive KA doses, resulting in higher reproducibility and lower inter-individual variability and mortality rates. Caution should be taken when translating this procedure to different strains of mice as inter-strain sensitivity to KA has been described before. The procedure can be performed in ~1 h by a trained researcher, while intrahippocampal administration of KA without placing recording electrodes can be done in 25 min, and can be easily adapted to the titrated intrahippocampal administration of other drugs.

Synergic Functions of miRNAs Determine Neuronal Fate of Adult Neural Stem Cells

Adult neurogenesis requires the precise control of neuronal versus astrocyte lineage determination in neural stem cells. While microRNAs (miRNAs) are critically involved in this step during development, their actions in adult hippocampal neural stem cells (aNSCs) has been unclear. As entry point to address that question we chose DICER, an endoribonuclease essential for miRNA biogenesis and other RNAi-related processes. By specific ablation of Dicer in aNSCs in vivo and in vitro, we demonstrate that miRNAs are required for the generation of new neurons, but not astrocytes, in the adult murine hippocampus. Moreover, we identify 11 miRNAs, of which 9 have not been previously characterized in neurogenesis, that determine neurogenic lineage fate choice of aNSCs at the expense of astrogliogenesis. Finally, we propose that the 11 miRNAs sustain adult hippocampal neurogenesis through synergistic modulation of 26 putative targets from different pathways.

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Dicer depletion in aNSCs impairs neurogenesis and stimulates astrogliogenesis

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Synergy of 11 miRNAs sustains neuronal fate of aNSCs

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miRNA converge on multiple targets in different pathways to induce neurogenesis

miR-375 and miR-205 Regulate the Invasion and Migration of Laryngeal Squamous Cell Carcinoma Synergistically via AKT-Mediated EMT

Previous studies have found that miR-375 and miR-205 were significantly dysregulated in laryngeal squamous cell carcinoma, which contributed to the invasion and migration of LSCC. However, the mechanisms of miR-375 and miR-205 regulating the invasion and migration of LSCC remain unknown. qRT-PCR was performed in 40 pairs of tissue samples to investigate the expression of miR-375 and miR-205 in LSCC and paracarcinoma tissues. To investigate whether or not miR-375 and miR-205 regulated the invasion and migration of LSCC synergistically via AKT-mediated epithelial-mesenchymal transition, miR-375 mimic and miR-205 inhibitor were transfected into SNU899 cells and miR-375 inhibitor and miR-205 mimic were transfected into SNU899 cells, respectively, with or without AKT inhibitor. Then the expressions of miR-375 and miR-205 were validated by qRT-PCR, cell migration and invasion were determined by wound healing assay and transwell invasive assay, and western blot analysis was performed to detect the expression of related proteins. Our results showed that miR-375 and miR-205 regulated the invasion and migration of LSCC via AKT-mediated EMT synergistically. In conclusion, our findings provided not only new information about the molecular mechanism of miRNAs regulating invasion and migration of LSCC, but also a theoretical principle for potential targeting therapy of laryngeal squamous carcinoma.

Effect of propofol on microRNA expression in rat primary embryonic neural stem cells

BACKGROUND

Propofol is a widely used intravenous anesthetic that is well-known for its protective effect in various human and animal disease models. However, the effects of propofol on neurogenesis, especially on the development of neural stem cells (NSCs), remains unknown. Related microRNAs may act as important regulators in this process.

METHODS

Published Gene Expression Omnibus (GEO) DataSets related to propofol were selected and re-analyzed to screen neural development-related genes and predict microRNA (miRNA) expression using bioinformatic methods. Screening of the genes and miRNAs was then validated by qRT-PCR analysis of propofol-treated primary embryonic NSCs.

RESULTS

Four differentially expressed mRNAs were identified in the screen and 19 miRNAs were predicted based on a published GEO DataSet. Two of four mRNAs and four of 19 predicted miRNAs were validated by qRT-PCR analysis of propofol-treated NSCs. Rno-miR-19a (Rno, Rattus Norvegicus) and rno-miR-137, and their target gene EGR2, as well as rno-miR-19b-2 and rno-miR-214 and their target gene ARC were found to be closely related to neural developmental processes, including proliferation, differentiation, and maturation of NSCs.

CONCLUSION

Propofol influences miRNA expression; however, further studies are required to elucidate the mechanism underlying the effects of propofol on the four miRNAs and their target genes identified in this study. In particular, the influence of propofol on the entire development process of NSCs remains to be clarified.

Identification of microRNAs with Dysregulated Expression in Status Epilepticus Induced Epileptogenesis

The involvement of miRNA in mesial temporal lobe epilepsy (MTLE) pathogenesis has increasingly become a focus of epigenetic studies. Despite advances, the number of known miRNAs with a consistent expression response during epileptogenesis is still small. Addressing this situation requires additional miRNA profiling studies coupled to detailed individual expression analyses. Here, we perform a miRNA microarray analysis of the hippocampus of Wistar rats 24 hours after intra-hippocampal pilocarpine-induced Status Epilepticus (H-PILO SE). We identified 73 miRNAs that undergo significant changes, of which 36 were up-regulated and 37 were down-regulated. To validate, we selected 5 of these (10a-5p, 128a-3p, 196b-5p, 352 and 324-3p) for RT-qPCR analysis. Our results confirmed that miR-352 and 196b-5p levels were significantly higher and miR-128a-3p levels were significantly lower in the hippocampus of H-PILO SE rats. We also evaluated whether the 3 miRNAs show a dysregulated hippocampal expression at three time periods (0h, 24h and chronic phase) after systemic pilocarpine-induced status epilepticus (S-PILO SE). We demonstrate that miR-128a-3p transcripts are significantly reduced at all time points compared to the naïve group. Moreover, miR-196b-5p was significantly higher only at 24h post-SE, while miR-352 transcripts were significantly up-regulated after 24h and in chronic phase (epileptic) rats. Finally, when we compared hippocampi of epileptic and non-epileptic humans, we observed that transcript levels of miRNAs show similar trends to the animal models. In summary, we successfully identified two novel dysregulated miRNAs (196b-5p and 352) and confirmed miR-128a-3p downregulation in SE-induced epileptogenesis. Further functional assays are required to understand the role of these miRNAs in MTLE pathogenesis.

Multi-omics profile of the mouse dentate gyrus after kainic acid-induced status epilepticus

Temporal lobe epilepsy (TLE) can develop from alterations in hippocampal structure and circuit characteristics, and can be modeled in mice by administration of kainic acid (KA). Adult neurogenesis in the dentate gyrus (DG) contributes to hippocampal functions and has been reported to contribute to the development of TLE. Some of the phenotypical changes include neural stem and precursor cells (NPSC) apoptosis, shortly after their birth, before they produce hippocampal neurons. Here we explored these early phenotypical changes in the DG 3 days after a systemic injection of KA inducing status epilepticus (KA-SE), in mice. We performed a multi-omics experimental setup and analyzed DG tissue samples using proteomics, transcriptomics and microRNA profiling techniques, detecting the expression of 2327 proteins, 13401 mRNAs and 311 microRNAs. We here present a description of how these data were obtained and make them available for further analysis and validation. Our data may help to further identify and characterize molecular mechanisms involved in the alterations induced shortly after KA-SE in the mouse DG.

The Human Bcl-2 Family Member Bcl-rambo Localizes to Mitochondria and Induces Apoptosis and Morphological Aberrations in Drosophila

Bcl-2 family proteins play a central role in regulating apoptosis. We previously reported that human Bcl-rambo, also termed BCL2L13, localized to mitochondria and induced apoptosis when overexpressed in human embryonic kidney 293T cells. However, the physiological function of Bcl-rambo currently remains unclear. In the present study, human Bcl-rambo was ectopically expressed in Drosophila melanogaster. Bcl-rambo mainly localized to the mitochondria of Drosophila Schneider 2 (S2) cells. The overexpression of Bcl-rambo, but not Bcl-rambo lacking a C-terminal transmembrane domain, induced apoptosis in S2 cells. Moreover, the ectopic expression of Bcl-rambo by a GAL4-UAS system induced aberrant morphological changes characterized by atrophied wing, split thorax, and rough eye phenotypes. Bcl-rambo induced the activation of effector caspases in eye imaginal discs. The rough eye phenotype induced by Bcl-rambo was partly rescued by the co-expression of p35, Diap1, and Diap2. By using this Drosophila model, we showed that human Bcl-rambo interacted genetically with Drosophila homologues of adenine nucleotide translocators and the autophagy-related 8 protein. The results of the present study demonstrated that human Bcl-rambo localized to mitochondria and at least regulated an apoptosis signaling pathway in Drosophila.