Project description:Substantial data indicate that microRNA-21 (miR-21) is significantly elevated in glioblastoma (GBM) and in many other tumors of various origins. This miRNA has been implicated in various aspects of carcinogenesis, including cellular proliferation, apoptosis and migration. We demonstrate that miR-21 regulates multiple genes associated with glioma cell apoptosis, migration, and invasiveness, including RECK and TIMP3, suppressors of malignancy and inhibitors of matrix metalloproteinases (MMPs). Specific inhibition of miR-21 with antisense olgonucleotides leads to elevated levels of RECK and TIMP3 and therefore reduces MMP activities in vitro and in a human model of glioma in nude mice. Moreover, down-regulation of miR-21 in glioma cells leads to decrease of their migratory and invasion abilities. Our data suggest that miR-21 contributes to the glioma malignancy by down-regulation of MMP inhibitors that leads to activation of MMPs thus promoting invasiveness of cancer cells. Our results also indicate that inhibition of a single oncomir like miR-21 with specific antisense molecules can provide a novel therapeutic approach for “physiological” modulation of multiple proteins whose expression is de-regulated in cancer.
Project description:Glioblastoma (GB), the most aggressive tumor of the central nervous system (CNS), has poor patient outcomes with limited effective treatments available. MicroRNA-21 (miR-21) is a known oncogene, abundantly expressed in many cancer types. MiR-21 promotes glioblastoma progression, and lack of miR-21 reduces tumorigenic potential of tumor. Here, we propose a single adeno-associated virus (AAV) vector strategy targeting miR-21 using the Staphylococcus aureus Cas9 ortholog (SaCas9) guided by a single-guide RNA (sgRNA). Our results demonstrate that AAV8 is a well-suited AAV serotype to express SaCas9-KKH/sgRNA at the tumor site in an orthotopic glioblastoma model. The SaCas9-KKH induced a genomic deletion, resulting in lowered miR-21 levels in the brain, leading to reduced tumor growth and improved overall survival. In this study we demonstrated that a single AAV-mediated mir-21 disruption influences glioma development resulting in beneficial anti-tumor outcomes in GB-bearing mice.
Project description:Method: Analysis of the transcriptomal changes of EV-GFP uptake by microglia after implantation of glioma cells into miR-21 null mouse brain. Result: miR-21 is transferred from glioma to microglia through EV, resulting in downregulation of miR-21 target mRNAs
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:Method: Analysis of the transcriptomal changes in wildtype mouse glioma tumor cells compared to miR-21 knockout glioma tumor cells (GL261) Result: transcriptional changes are driven through miR-21
Project description:As the evolution of miRNA genes has been found to be one of the important factors in formation of the modern type of man, we performed a comparative analysis of the evolution of miRNA genes in two archaic hominines, Homo sapiens neanderthalensis and Homo sapiens denisova, and elucidated the expression of their target mRNAs in bain.A comparative analysis of the genomes of primates, including species in the genus Homo, identified a group of miRNA genes having fixed substitutions with important implications for the evolution of Homo sapiens neanderthalensis and Homo sapiens denisova. The mRNAs targeted by miRNAs with mutations specific for Homo sapiens denisova exhibited enhanced expression during postnatal brain development in modern humans. By contrast, the expression of mRNAs targeted by miRNAs bearing variations specific for Homo sapiens neanderthalensis was shown to be enhanced in prenatal brain development.Our results highlight the importance of changes in miRNA gene sequences in the course of Homo sapiens denisova and Homo sapiens neanderthalensis evolution. The genetic alterations of miRNAs regulating the spatiotemporal expression of multiple genes in the prenatal and postnatal brain may contribute to the progressive evolution of brain function, which is consistent with the observations of fine technical and typological properties of tools and decorative items reported from archaeological Denisovan sites. The data also suggest that differential spatial-temporal regulation of gene products promoted by the subspecies-specific mutations in the miRNA genes might have occurred in the brains of Homo sapiens denisova and Homo sapiens neanderthalensis, potentially contributing to the cultural differences between these two archaic hominines.
Project description:PurposeWe investigated the evidence of recent positive selection in the human phototransduction system at single nucleotide polymorphism (SNP) and gene level.MethodsSNP genotyping data from the International HapMap Project for European, Eastern Asian, and African populations was used to discover differences in haplotype length and allele frequency between these populations. Numeric selection metrics were computed for each SNP and aggregated into gene-level metrics to measure evidence of recent positive selection. The level of recent positive selection in phototransduction genes was evaluated and compared to a set of genes shown previously to be under recent selection, and a set of highly conserved genes as positive and negative controls, respectively.ResultsSix of 20 phototransduction genes evaluated had gene-level selection metrics above the 90th percentile: RGS9, GNB1, RHO, PDE6G, GNAT1, and SLC24A1. The selection signal across these genes was found to be of similar magnitude to the positive control genes and much greater than the negative control genes.ConclusionsThere is evidence for selective pressure in the genes involved in retinal phototransduction, and traces of this selective pressure can be demonstrated using SNP-level and gene-level metrics of allelic variation. We hypothesize that the selective pressure on these genes was related to their role in low light vision and retinal adaptation to ambient light changes. Uncovering the underlying genetics of evolutionary adaptations in phototransduction not only allows greater understanding of vision and visual diseases, but also the development of patient-specific diagnostic and intervention strategies.
Project description:Cortical thickness has been investigated since the beginning of the 20th century, but we do not know how similar the cortical thickness profiles among humans are. In this study, the local similarity of cortical thickness profiles was investigated using sliding window methods. Here, we show that approximately 5% of the cortical thickness profiles are similarly expressed among humans while 45% of the cortical thickness profiles show a high level of heterogeneity. Therefore, heterogeneity is the rule, not the exception. Cortical thickness profiles of somatosensory homunculi and the anterior insula are consistent among humans, while the cortical thickness profiles of the motor homunculus are more variable. Cortical thickness profiles of homunculi that code for muscle position and skin stimulation are highly similar among humans despite large differences in sex, education, and age. This finding suggests that the structure of these cortices remains well preserved over a lifetime. Our observations possibly relativize opinions on cortical plasticity.
Project description:Overexpression of miR-31 inhibits the migration and invasion ability of glioma cell. We sought to obtain the genes regulated by mir-31 in glioma cell line.