Reactive-site mutants of N-TIMP-3 that selectively inhibit ADAMTS-4 and ADAMTS-5: biological and structural implications.

Published versio

Catalytic sites for 3'- and 5' incision of Escherichia coli nucleotide excision repair are both located in UvrC.

Medical Biochemistr

The effect of the DNA flanking the lesion on formation of the UvrB-DNA preincision complex - Mechanism for the UvrA-mediated loading of UvrB onto a DNA damaged site

Bio-organic Synthesi

The role of ATP binding and hydrolysis by UvrB during nucleotide excision repair

Bio-organic Synthesi

Microparticles Carrying Sonic Hedgehog Favor Neovascularization through the Activation of Nitric Oxide Pathway in Mice

BACKGROUND: Microparticles (MPs) are vesicles released from plasma membrane upon cell activation and during apoptosis. Human T lymphocytes undergoing activation and apoptosis generate MPs bearing morphogen Shh (MPs(Shh+)) that are able to regulate in vitro angiogenesis.METHODOLOGY/PRINCIPAL FINDINGS: Here, we investigated the ability of MPs(Shh+) to modulate neovascularization in a model of mouse hind limb ischemia. Mice were treated in vivo for 21 days with vehicle, MPs(Shh+), MPs(Shh+) plus cyclopamine or cyclopamine alone, an inhibitor of Shh signalling. Laser doppler analysis revealed that the recovery of the blood flow was 1.4 fold higher in MPs(Shh+)-treated mice than in controls, and this was associated with an activation of Shh pathway in muscles and an increase in NO production in both aorta and muscles. MPs(Shh+)-mediated effects on flow recovery and NO production were completely prevented when Shh signalling was inhibited by cyclopamine. In aorta, MPs(Shh+) increased activation of eNOS/Akt pathway, and VEGF expression, being inhibited by cyclopamine. By contrast, in muscles, MPs(Shh+) enhanced eNOS expression and phosphorylation and decreased caveolin-1 expression, but cyclopamine prevented only the effects of MPs(Shh+) on eNOS pathway. Quantitative RT-PCR revealed that MPs(Shh+) treatment increased FGF5, FGF2, VEGF A and C mRNA levels and decreased those of α5-integrin, FLT-4, HGF, IGF-1, KDR, MCP-1, MT1-MMP, MMP-2, TGFβ1, TGFβ2, TSP-1 and VCAM-1, in ischemic muscles. CONCLUSIONS/SIGNIFICANCE: These findings suggest that MPs(Shh+) may contribute to reparative neovascularization after ischemic injury by regulating NO pathway and genes involved in angiogenesis

Polyoma Virus-Induced Osteosarcomas in Inbred Strains of Mice: Host Determinants of Metastasis

The mouse polyoma virus induces a broad array of solid tumors in mice of many inbred strains. In most strains tumors grow rapidly but fail to metastasize. An exception has been found in the Czech-II/Ei mouse in which bone tumors metastasize regularly to the lung. These tumors resemble human osteosarcoma in their propensity for pulmonary metastasis. Cell lines established from these metastatic tumors have been compared with ones from non-metastatic osteosarcomas arising in C3H/BiDa mice. Osteopontin, a chemokine implicated in migration and metastasis, is known to be transcriptionally induced by the viral middle T antigen. Czech-II/Ei and C3H/BiDa tumor cells expressed middle T and secreted osteopontin at comparable levels as the major chemoattractant. The tumor cell lines migrated equally well in response to recombinant osteopontin as the sole attractant. An important difference emerged in assays for invasion in which tumor cells from Czech-II/Ei mice were able to invade across an extracellular matrix barrier while those from C3H/BiDa mice were unable to invade. Invasive behavior was linked to elevated levels of the metalloproteinase MMP-2 and of the transcription factor NFAT. Inhibition of either MMP-2 or NFAT inhibited invasion by Czech-II/Ei osteosarcoma cells. The metastatic phenotype is dominant in F1 mice. Osteosarcoma cell lines from F1 mice expressed intermediate levels of MMP-2 and NFAT and were invasive. Osteosarcomas in Czech-II/Ei mice retain functional p53. This virus-host model of metastasis differs from engineered models targeting p53 or pRb and provides a system for investigating the genetic and molecular basis of bone tumor metastasis in the absence of p53 loss

Matrix Metalloproteinase-1 and -9 in Human Placenta during Spontaneous Vaginal Delivery and Caesarean Sectioning in Preterm Pregnancy

Preterm birth is a major public health problem in terms of loss of life, long-term and short term disabilities worldwide. The process of parturition (both term and preterm) involves intensive remodelling of the extracellular matrix (ECM) in the placenta and fetal membranes by matrix metalloproteinases (MMPs). Our previous studies show reduced docosahexaenoic acid (DHA) in women delivering preterm. Further omega 3 fatty acids are reported to regulate MMP levels. This study was undertaken to examine the placental levels of MMPs and their association with placental DHA levels in women delivering preterm. The levels of MMP-1 and MMP-9 in 74 women delivering preterm (52 by spontaneous vaginal delivery and 22 by caesarean sectioning) and 75 women delivering at term (59 by spontaneous vaginal delivery and 16 by caesarean sectioning) were determined by enzyme-linked immunosorbent assay (ELISA) and their association with placental DHA was studied. Placental MMP-1 levels were higher (p<0.05) in women delivering preterm (both by spontaneous vaginal delivery and caesarean sectioning) as compared to those delivering at term. In contrast, placental MMP-9 levels in preterm pregnancies was higher (p<0.05) in women with spontaneous vaginal delivery while lower (p<0.05) in women delivering by caesarean sectioning. Low placental DHA was associated with higher placental MMP-9 levels. Our study suggests a differential effect of mode of delivery on the levels of MMPs from placenta. Further this study suggests a negative association of DHA and the levels of MMP-9 in human placenta although the mechanisms need further study