Ozumi K.,University of Illinois at Chicago |
Sudhahar V.,University of Illinois at Chicago |
Kim H.W.,University of Illinois at Chicago |
Chen G.-F.,University of Illinois at Chicago |
And 10 more authors.
Hypertension | Year: 2012
Extracellular superoxide dismutase (SOD3) is a secretory copper enzyme involved in protecting angiotensin II (Ang II)-induced hypertension. We found previously that Ang II upregulates SOD3 expression and activity as a counterregulatory mechanism; however, underlying mechanisms are unclear. Antioxidant 1 (Atox1) is shown to act as a copper-dependent transcription factor, as well as a copper chaperone, for SOD3 in vitro, but its role in Ang II-induced hypertension in vivo is unknown. Here we show that Ang II infusion increases Atox1 expression, as well as SOD3 expression and activity, in aortas of wild-type mice, which are inhibited in mice lacking Atox1. Accordingly, Ang II increases vascular superoxide production, reduces endothelium-dependent vasodilation, and increases vasoconstriction in mesenteric arteries to a greater extent in Atox1 than in wild-type mice. This contributes to augmented hypertensive response to Ang II in Atox1 mice. In cultured vascular smooth muscle cells, Ang II promotes translocation of Atox1 to the nucleus, thereby increasing SOD3 transcription by binding to Atox1-responsive element in the SOD3 promoter. Furthermore, Ang II increases Atox1 binding to the copper exporter ATP7A, which obtains copper from Atox1, as well as translocation of ATP7A to plasma membranes, where it colocalizes with SOD3. As its consequence, Ang II decreases vascular copper levels, which is inhibited in Atox1 mice. In summary, Atox1 functions to prevent Ang II-induced endothelial dysfunction and hypercontraction in resistant vessels, as well as hypertension, in vivo by reducing extracellular superoxide levels via increasing vascular SOD3 expression and activity. © 2012 American Heart Association, Inc. Source
Yang S.,National Renewable Energy Laboratory |
Franden M.A.,National Renewable Energy Laboratory |
Brown S.D.,Biosciences Division |
Brown S.D.,Oak Ridge National Laboratory |
And 3 more authors.
Biotechnology for Biofuels | Year: 2014
Background: Lignocellulosic biomass is a promising renewable feedstock for biofuel production. Acetate is one of the major inhibitors liberated from hemicelluloses during hydrolysis. An understanding of the toxic effects of acetate on the fermentation microorganism and the efficient utilization of mixed sugars of glucose and xylose in the presence of hydrolysate inhibitors is crucial for economic biofuel production.Results: A new microarray was designed including both coding sequences and intergenic regions to investigate the acetate stress responses of Zymomonas mobilis 8b when using single carbon sources of glucose or xylose, or mixed sugars of both glucose and xylose. With the supplementation of exogenous acetate, 8b can utilize all the glucose with a similar ethanol yield, although the growth, final biomass, and ethanol production rate were reduced. However, xylose utilization was inhibited in both media containing xylose or a mixed sugar of glucose and xylose, although the performance of 8b was better in mixed sugar than xylose-only media. The presence of acetate caused genes related to biosynthesis, the flagellar system, and glycolysis to be downregulated, and genes related to stress responses and energy metabolism to be upregulated. Unexpectedly, xylose seems to pose more stress on 8b, recruiting more genes for xylose utilization, than does acetate. Several gene candidates based on transcriptome results were selected for genetic manipulation, and a TonB-dependent receptor knockout mutant was confirmed to have a slight advantage regarding acetate tolerance.Conclusions: Our results indicate Z. mobilis utilized a different mechanism for xylose utilization, with an even more severe impact on Z. mobilis than that caused by acetate treatment. Our study also suggests redox imbalance caused by stressful conditions may trigger a metabolic reaction leading to the accumulation of toxic intermediates such as xylitol, but Z. mobilis manages its carbon and energy metabolism through the control of individual reactions to mitigate the stressful conditions. We have thus provided extensive transcriptomic datasets and gained insights into the molecular responses of Z. mobilis to the inhibitor acetate when grown in different sugar sources, which will facilitate future metabolic modeling studies and strain improvement efforts for better xylose utilization and acetate tolerance. © 2014 Yang et al. Source
Ashino T.,University of Illinois at Chicago |
Sudhahar V.,University of Illinois at Chicago |
Urao N.,Center for Lung and Vascular Biology |
Oshikawa J.,Center for Lung and Vascular Biology |
And 12 more authors.
Circulation Research | Year: 2010
Rationale: Copper, an essential nutrient, has been implicated in vascular remodeling and atherosclerosis with unknown mechanism. Bioavailability of intracellular copper is regulated not only by the copper importer CTR1 (copper transporter 1) but also by the copper exporter ATP7A (Menkes ATPase), whose function is achieved through copper-dependent translocation from trans-Golgi network (TGN). Platelet-derived growth factor (PDGF) promotes vascular smooth muscle cell (VSMC) migration, a key component of neointimal formation. Objective: To determine the role of copper transporter ATP7A in PDGF-induced VSMC migration. Methods and results: Depletion of ATP7A inhibited VSMC migration in response to PDGF or wound scratch in a CTR1/copper-dependent manner. PDGF stimulation promoted ATP7A translocation from the TGN to lipid rafts, which localized at the leading edge, where it colocalized with PDGF receptor and Rac1, in migrating VSMCs. Mechanistically, ATP7A small interfering RNA or CTR small interfering RNA prevented PDGF-induced Rac1 translocation to the leading edge, thereby inhibiting lamellipodia formation. In addition, ATP7A depletion prevented a PDGF-induced decrease in copper level and secretory copper enzyme precursor prolysyl oxidase (Pro-LOX) in lipid raft fraction, as well as PDGF-induced increase in LOX activity. In vivo, ATP7A expression was markedly increased and copper accumulation was observed by synchrotron-based X-ray fluorescence microscopy at neointimal VSMCs in wire injury model. Conclusions: These findings suggest that ATP7A plays an important role in copper-dependent PDGF-stimulated VSMC migration via recruiting Rac1 to lipid rafts at the leading edge, as well as regulating LOX activity. This may contribute to neointimal formation after vascular injury. Our findings provide insight into ATP7A as a novel therapeutic target for vascular remodeling and atherosclerosis. © 2010 American Heart Association, Inc. Source
Lives of soldiers and others injured in remote locations could be saved with a cell-free protein synthesis system developed at the Department of Energy's Oak Ridge National Laboratory. The device, a creation of a team led by Andrea Timm and Scott Retterer of the lab's Biosciences Division, uses microfabricated bioreactors to facilitate the on-demand production of therapeutic proteins for medicines and biopharmaceuticals. Making these miniature factories cell-free, which eliminates the maintenance of a living system, simplifies the process and lowers cost. "With this approach, we can produce more protein faster, making our technology ideal for point-of-care use," Retterer said. "The fact it's cell-free reduces the infrastructure needed to produce the protein and opens the possibility of creating proteins when and where you need them, bypassing the challenge of keeping the proteins cold during shipment and storage." ORNL's bioreactor features elegance through a permeable nanoporous membrane and serpentine design fabricated using a combination of electron beam and photolithography and advanced material deposition processes. This design enables prolonged cell-free reactions for efficient production of proteins, making it easily adaptable for use in isolated locations and at disaster sites. From a functional perspective, the design uses long serpentine channels integrated in a way to allow the exchange of materials between parallel reactor and feeder channels. With this approach, the team can control the exchange of metabolites, energy and species that inhibit production of the desired protein. Through other design features, researchers extend reaction times and improve yields. "We show that the microscale bioreactor design produces higher protein yields than conventional tube-based batch formats and that product yields can be dramatically improved by facilitating small molecule exchange with the dual-channel bioreactor," the authors wrote in their paper, published in the journal Small. The researchers also note that on-demand biologic synthesis would aid the production of drugs that are costly to mass-produce, including orphan drugs and personalized medicines.
Even if a guest walked into the kitchen and held their breath, they still would slough off 10 million bacterial cells in just 60 minutes through skin shed. While the idea may seem revolting, Jack A. Gilbert, UChicago associate professor in ecology & evolution and group leader for microbial ecology in the Biosciences Division at the U.S. Department of Energy's Argonne National Laboratory, assures us it's not. "Nearly all of the germs graciously donated by our friends and family are not disgusting," said Gilbert, who has made a career of exploring how microbial communities assemble themselves in natural and man-made environments. "They are probably good for us in many different ways." Gilbert said our over-sanitized environment may ultimately leave us weaker than our ancestors, who were agrarian and were constantly surrounded by a wide variety of plants and animals. Their bodies adapted to such changes—and so our bodies expect to encounter them, too, he said. "Our ancestors experienced many different types of bacteria on a regular basis," he said. "When you live with such rich biodiversity, the body expects to see it and when it doesn't, it freaks out, which is why we are seeing an explosion in allergies, asthma and hay fever. Our bodies are overreacting to the absence of these organisms." Our constant hand washing—though it might prevent a nasty flu—might also keep us from developing immunities. "We have done a really good job at keeping the bad bugs at bay," Gilbert said, "but we've failed at keeping in those that we need because we live an indoor, sedentary lifestyle." Inviting friends and family to come around on a regular basis may help stimulate our immune systems, he said. Likewise, having very young children interact with a wide variety of animals is only beneficial to their health and greatly outweighs the slim chance of exposure to something harmful, he said. In fact, Gilbert believes some of the social rituals we carry out today—hand shaking, hugging, kissing—may have evolved over millennia as a way to share, spread and develop immunities to bacteria. Kissing, for example, may promote healthy digestion, train the immune system and may even lead to better cognition, Gilbert said. Germs are so prevalent and impossible to eliminate, Gilbert said, there is no need to go overboard scrubbing the house after holiday gatherings. "I would say there is no real reason to increase cleanliness protocols in your property unless one of your guests is really sick, in which case you can isolate them—or tell them not to come over at all," he said.