Homo sapiens
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PROVIDER: PRJNA827594 | ENA |
REPOSITORIES: ENA
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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.
| S-EPMC2531291 | biostudies-literature
Project description:RNA extracted at 240min. Samples are rRNA depleted. Expression measurement of Homo sapiens genes.
2019-07-31 | GSE114179 | GEO
Project description:The impairment of the intestinal barrier will lead to the accumulation of fat and harmful substances in the liver, inducing hepatic steatosis or steatohepatitis. Zhang et al. identified NSD2 in the intestine as a novel and essential regulator of hepatic steatosis. NSD2 directly regulates transcriptional activation of ERN1 through the modification of H3 dimethylated on lysine 36 (H3K4me36), thereby activating the ERN1-JNK axis to induce inflammatory response, intestinal barrier impairment, and hepatic steatosis. This functional mechanism of NSD2 provides a potential therapeutic target for this disease.
2024-05-01 | GSE254668 | GEO
Project description:The impairment of the intestinal barrier will lead to the accumulation of fat and harmful substances in the liver, inducing hepatic steatosis or steatohepatitis. Zhang et al. identified NSD2 in the intestine as a novel and essential regulator of hepatic steatosis. NSD2 directly regulates transcriptional activation of ERN1 through the modification of H3 dimethylated on lysine 36 (H3K4me36), thereby activating the ERN1-JNK axis to induce inflammatory response, intestinal barrier impairment, and hepatic steatosis. This functional mechanism of NSD2 provides a potential therapeutic target for this disease.
2024-05-01 | GSE254667 | GEO
Project description:17β-hydroxysteroid dehydrogenase-13 (17β-HSD13) is a liver-rich lipid droplet associated protein, encoding by gene HSD17B13, that acted as an important regulator of hepatic lipid metabolism. Increased expression of 17β-HSD13 promotes hepatic lipid accumulation in rodents, and a common loss-of-function variant of HSD17B13 (rs72613567: TA) is related to better outcome in patients with various chronic liver diseases. To understand the role of 17β-HSD13 in liver lipid metabolism under normal and high-fat feeding conditions, we characterized the effect of protein phosphorylation of 17β-HSD13 on hepatic lipid homeostasis. We identify Ser33 as an important protein kinase A (PKA)-mediated phosphorylation site of 17β-HSD13 that physically interact with ATGL and facilitates its translocation to lipid droplets to enhance lipolysis. Mutation of Ser33 to Ala (S33A) in 17β-HSD13 reduces ATGL-dependent lipolysis and increases lipid droplet size in cultured hepatocytes by reducing CGI-58-mediated ATGL activation. Consistently, a transgenic knock-in mouse strain carrying HSD17B13 S33A mutation (HSD17B1333A/A) spontaneously develops liver steatosis with reduced lipolysis. Moreover, HSD17B1333A/A mice are more prone to high fat-induced hepatic steatosis and inflammation. Finally, we found Reproterol, a potential HSD17B13 modulator and FDA-approved drug, confers a protection against liver steatosis possibly through phosphorylation of 17β-HSD13 at Ser33 in a PKA-dependent manner. In summary, we demonstrate a critical role and the underlying mechanism of hepatic 17β-HSD13 phosphorylation in the pathogenesis of NAFLD. Our findings highlight the potential of targeting 17β-HSD13 phosphorylation as a novel therapeutic approach for NAFLD.
2023-03-11 | PXD037262 | Pride
Project description:Pyrimidine catabolism is implicated in hepatic steatosis. Dihydropyrimidine Dehydrogenase (DPYD) is an enzyme responsible for uracil and thymine catabolism, and DPYD human genetic variability affects clinically observed toxicity following 5-Fluorouracil (5-FU) administration. In an in vitro model of diet-inducedfatty acid-induced steatosis, the pharmacologic inhibition of DPYD resulted in protection from lipid accumulation. Additionally, a gain-of-function mutation of DPYD, created through clustered regularly interspaced short palindromic repeats associated protein 9 (CRISPR-Cas9) engineering, led to an increased lipid burden, which was associated with altered mitochondrial functionality in a hepatocarcionma cell line. The studies presented herein describe a novel role for DPYD in hepatocyte metabolic regulation as a modulator of hepatic steatosis.
2022-04-25 | GSE201169 | GEO
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.
| S-EPMC4686780 | biostudies-literature
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.
| S-EPMC3743458 | biostudies-literature
Project description:SPO11-promoted DNA double-strand breaks (DSBs) formation is a crucial step for meiotic recombination, and it is indispensable to detect the broken DNA ends accurately for dissecting the molecular mechanisms behind. Here, we report a novel technique, named DEtail-seq (DNA End tailing followed by sequencing), that can directly and quantitatively capture the meiotic DSB 3’ overhang hotspots at single-nucleotide resolution.
2023-01-08 | GSE154227 | GEO