Project description:This study aims to identify specific miRNAs profiles in osteoporotic patients with and without vertebral fractures. MiRNAs array analysis was performed on the plasma samples including a pool of 6 miRNA samples from osteoporotic patients with vertebral fractures, a pool of 6 miRNA samples from osteoporotic patients without fracture and another pool of 6 miRNA samples from nonosteoporotic patients to identify regulated miRNAs in the plasma.
Project description:The objective of this study was the identification of serum microRNAs that can differentiate osteoporotic fracture patients with and without type-2 diabetes from healthy control subjects. For that purpose circulating microRNAs were profiled by real-time quantitative PCR using a custom 384-well panel in 200 µl serum samples. Univariate and multivariate statistical tools were used in order to identify single as well as combinations of circulating microRNas that were characteristic of patients with prevalent osteoporotic fractures: a qRT-PCR-based classifier consisting of miR-550a-5p, miR-96-5p, miR-32-3p and miR-486-5p can distinguish T2D women with (DMFx) and without fragility fractures (DM) with high specifitiy and sensitivity (AUC = 0.93). A classifier consisting of miR-188-3p, miR-382-3p, miR-942 and miR-155-5p was capable of differentiating between postmenopausal women with osteoporotic fractures and fracture-free controls with an AUC of 0.98.
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:Current clinical approaches to promote osteoporotic fracture healing primarily target osteoclast biology, overlooking the negative regulatory role of fibroblasts in fracture healing. Perioperative bisphosphonates (BPs) used in anti-osteoporosis treatment for osteoporotic fractures have become a consensus worldwide. However, excessive fibrosis is induced simultaneously, leading to fracture non-union and atypical femur fractures. It is highly desirable to inhibit osteoclasts but block fibrosis. In this study, an magnesium ions (Mg2+)-BPs MOF-based bone adhesive material was designed to down-regulate SOST and weaken SOST/TGF-β signaling pathway through Mg2+ through transcriptome analysis, thus inhibiting fibrotic differentiation and subsequent disordered mineralization.
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.