Project description:Using NGS-based miRNome, followed by AGO2-RIP-seq, the miR-34c and miR-449a and their direct targets were identified as factors involved in the development and progression of sinonasal cancers (SNCs). Both miR-34c and miR-449a were independent prognostic biomarkers and were associated with patient outcome.
Project description:Using NGS-based miRNome, followed by AGO2-RIP-seq, the miR-34c and miR-449a and their direct targets were identified as factors involved in the development and progression of sinonasal cancers (SNCs). Both miR-34c and miR-449a were independent prognostic biomarkers and were associated with patient outcome.
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:Persistent pulmonary hypertension of the newborn (PPHN) occurs when pulmonary vascular resistance (PVR) fails to decrease at birth. Decreased angiogenesis in the lung contributes to the persistence of high PVR at birth. MicroRNAs (miRNAs) regulate gene expression through transcript binding and degradation. They were implicated in dysregulated angiogenesis in cancer and cardiovascular disease. We investigated whether altered miRNA levels contribute to impaired angiogenesis in PPHN. We used a fetal lamb model of PPHN induced by prenatal ductus arteriosus constriction and sham ligation as controls. We performed RNA sequencing of pulmonary artery endothelial cells (PAECs) isolated from control and PPHN lambs. We observed a differentially expressed miRNA profile in PPHN for organ development, cell-cell signaling, and cardiovascular function. MiR-34c was upregulated in PPHN PAECs compared to controls. Exogenous miR34c mimics decreased angiogenesis by control PAEC and anti-miR34c improved angiogenesis of PPHN PAEC in vitro. Notch1, a predicted target for miR-34c by bioinformatics, was decreased in PPHN PAECs, along with Notch1 downstream targets, Hey1 and Hes1. Exogenous miR-34c decreased Notch1 expression in control PAECs and anti-miR-34c restored Notch1 and Hes1 expression in PPHN PAECs. We conclude that increased miR-34c in PPHN contributes to impaired angiogenesis by decreasing Notch1 expression in PAECs."
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:miR-34a and miR-34c were found up-regulated at wound-edges of human venous ulcer compared to nomal wound and the intact skin; however their biological role in keratinocytes during wound repair has not been studied. To study the genes regulated by miR-34a and miR-34c, we transfected miR-34a and miR-34c mimic into human primary epidermal keratinocytes to overexpress them. We performed a global transcriptome analysis of keratinocytes upon overexpression of miR-34a or miR-34c using Affymetrix arrays.