Investigating the Roles of Zinc-Binding Protein (ZBP-89) and Rela (NFkB-p65) in the Regulation of Matrix Metalloproteinase 1 (MMP1) Gene Expression

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases with the unique ability to breakdown virtually the entire extracellular matrix (ECM). Through ECM remodeling, MMPs play an important role in normal development, tissue repair, angiogenesis, and apoptosis. Studies have shown that unregulated MMP expression plays a role in many cancers and chronic inflammatory diseases. Previous research has used gene sequence analysis ofthe MMP-1 promoter to identify a putative ZBP-89 binding site at -1969 bp. Chromatin immuneprecipitation experiments showed that both ZBP-89 and Re!A (p65) could bind to this binding site. In this thesis research, transfection experiments were used to explore the role of ZBP-89 and p65 in regulating MMP-1 gene expression. Two versions of a MMP-1 plasmid were used: a Long MMP-1 plasmid with a longer MMP-1 promoter (2.2 kb) that contains the distal putative binding site and a Short MMP-1 plasmid with a shorter promoter (1.1 kb) that does not. Results showed that ZBP-89 alone can increase long MMP-1 plasmid expression in COS-1 cells and ZBP- 89 and p65 synergistically increase long MMP-1 plasmid expression in a dose-dependent manner. This suggests that ZBP-89 may cooperate with NFkB-p65 in MMP-1 gene regulation. ZBP-89 and p65 did not increase short MMP-1 plasmid expression in COS-1 cells or A549 cells. These results support our hypothesis that ZBP-89 and p65 work directly through the putative binding site at -1969 bp. This research further expands our understanding of MMP-1 gene regulation and can aid the development of MMP targeted therapy

Earth-Abundant Tin Sulfide-Based Photocathodes for Solar Hydrogen Production.

Tin-based chalcogenide semiconductors, though attractive materials for photovoltaics, have to date exhibited poor performance and stability for photoelectrochemical applications. Here, a novel strategy is reported to improve performance and stability of tin monosulfide (SnS) nanoplatelet thin films for H2 production in acidic media without any use of sacrificial reagent. P-type SnS nanoplatelet films are coated with the n-CdS buffer layer and the TiO2 passivation layer to form type II heterojunction photocathodes. These photocathodes with subsequent deposition of Pt nanoparticles generate a photovoltage of 300 mV and a photocurrent density of 2.4 mA cm-2 at 0 V versus reversible hydrogen electrode (RHE) for water splitting under simulated visible-light illumination (λ > 500 nm, Pin = 80 mW cm-2). The incident photon-to-current efficiency at 0 V versus RHE for H2 production reach a maximum of 12.7% at 575 nm with internal quantum efficiency of 13.8%. The faradaic efficiency for hydrogen evolution remains close to unity after 6000 s of illumination, confirming the robustness of the heterojunction for solar H2 production

Stability and Electronic Properties of TiO2 Nanostructures With and Without B and N Doping

We address one of the main challenges to TiO2-photocatalysis, namely band gap narrowing, by combining nanostructural changes with doping. With this aim we compare TiO2's electronic properties for small 0D clusters, 1D nanorods and nanotubes, 2D layers, and 3D surface and bulk phases using different approximations within density functional theory and GW calculations. In particular, we propose very small (R < 0.5 nm) but surprisingly stable nanotubes with promising properties. The nanotubes are initially formed from TiO2 layers with the PtO2 structure, with the smallest (2,2) nanotube relaxing to a rutile nanorod structure. We find that quantum confinement effects - as expected - generally lead to a widening of the energy gap. However, substitutional doping with boron or nitrogen is found to give rise to (meta-)stable structures and the introduction of dopant and mid-gap states which effectively reduce the band gap. Boron is seen to always give rise to n-type doping while depending on the local bonding geometry, nitrogen may give rise to n-type or p-type doping. For under coordinated TiO2 surface structures found in clusters, nanorods, nanotubes, layers and surfaces nitrogen gives rise to acceptor states while for larger clusters and bulk structures donor states are introduced

Trends in Metal Oxide Stability for Nanorods, Nanotubes, and Surfaces

The formation energies of nanostructures play an important role in determining their properties, including the catalytic activity. For the case of 15 different rutile and 8 different perovskite metal oxides, we find that the density functional theory (DFT) calculated formation energies of (2,2) nanorods, (3,3) nanotubes, and the (110) and (100) surfaces may be described semi-quantitatively by the fraction of metal--oxygen bonds broken and the bonding band centers in the bulk metal oxide

Electrochemical oxidation of phosphatidylethanolamines studied by mass spectrometry

Phosphatidylethanolamines (PEs) are widely present in cellular membranes and lipoproteins. Oxidation of PE fatty acyl chains generates several oxidized products, exerting a vast number of biological functions, not totally unveiled yet. In vitro biomimetic models have been used to identify oxidized PEs and to develop analytical strategies for their targeted detection in vivo. Most of the models are based on oxidation by reactive oxygen species (ROS), but the oxidative metabolism of PE also relies on controlled reactions catalyzed by enzymes as lipoxygenase, which can be mimicked by electrochemical (EC) oxidation. In this study, 3 PE standards (1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphoethanolamine (POPE), 1‐palmitoyl‐2‐linoleoyl‐sn‐glycero‐3‐phosphoethanolamine (PLPE), and 1‐palmitoyl‐2‐arachidonoyl‐sn‐glycero‐3‐phosphoethanolamine (PAPE)) were oxidized by EC oxidation, using an EC flow‐through cell system as a biomimetic model of oxidative injury. The new oxidation products were identified by online EC electrospray ionization mass spectrometry (EC‐ESI‐MS and MS/MS). Long‐chain and short‐chain oxidation products were identified, bearing modifications in the sn‐2 acyl chains, whereas the oxidation pattern was dependent on the unsaturation level. Long‐chain oxidation products of PEs (keto, hydroxy, hydroperoxy, poly‐hydroperoxy derivatives) were identified, bearing up to 5, 7, and 10 oxygens for POPE, PLPE, and PAPE, respectively. Fourteen short‐chain oxidation products, 7 from PLPE, and 7 from PAPE, including aldehydes, γ‐hydroxy‐α,β‐aldehydes, and dicarboxylic acids were characterized. Some of these oxidized species were previously reported during the oxidative metabolism of PEs driven by ROS. The EC‐ESI‐MS platform was, therefore, able to mimic the oxidative metabolism of PEs mediated by ROS.publishe

Elucidation of Phosphatidylcholine Composition in Krill Oil Extracted from Euphausia superba

High performance liquid chromatography-electrospray tandem mass spectrometry was used to elucidate the phospholipids in krill oil extracted from Euphausia superba, an emerging source for human nutritional supplements. The study was carried out in order to map the species of the choline-containing phospholipid classes: phosphatidylcholine and lyso-phosphatidylcholine. In addition, the prevalent phosphatidylcholine class was quantified and the results compared with prior analysis. The qualification was performed with separation on a reverse phase chromatography column, while the quantification was obtained with class separation on a normal phase chromatography column. An Orbitrap system was used for the detection, and pulsed-Q dissociation fragmentation was utilized for the identification of the species. An asymmetrical exclusion list was applied for detection of phospholipid species of lower concentration, significantly improving the number of species observed. A total of 69 choline-containing phospholipids were detected, whereof 60 phosphatidylcholine substances, among others seven with probable omega-3 fatty acids in both sn-1 and sn-2. The phosphatidylcholine concentration was estimated to be 34 ± 5 g/100 g oil (n = 5). These results confirm the complexity of the phospholipid composition of krill oil, and the presence of long chained, heavily unsaturated fatty acids