8-Oxoguanine DNA Glycosylase-1 Augments Proinflammatory Gene Expression by Facilitating the Recruitment of Site-Specific Transcription Factors

Among the insidious DNA base lesions, 8-oxo-7,8-dihydroguanine (8-oxoG) is one of the most abundant, a lesion that arises through the attack by reactive oxygen species on guanine, especially when located in cis-regulatory elements. 8-oxoG is repaired by the 8-oxoguanine glycosylase 1 (OGG1)-initiated DNA base excision repair (BER) pathway. Here we investigated whether 8-oxoG repair by OGG1 in promoter regions is compatible with a prompt gene expression and a host innate immune response. For this purpose, we utilized a mouse model of airway inflammation, supplemented with cell cultures, chromatin immunoprecipitation, siRNA knockdown, real-time PCR, Comet and reporter transcription assays. Our data show that exposure of cells to tumor necrosis factor alpha (TNF-α) altered cellular redox, increased the 8-oxoG level in DNA, recruited OGG1 to promoter sequences and transiently inhibited BER of 8-oxoG. Promoter-associated OGG1 then enhanced NF-êB/RelA binding to cis-elements and facilitated recruitment of Specificity Protein 1 (SP1), transcription initiation factor II-D (TFIID), and phospho-RNA polymerase II, resulting in the rapid expression of chemokines/cytokines and inflammatory cell accumulation in mouse airways. siRNA depletion of OGG1 or prevention of guanine oxidation significantly decreased TNF-α-induced inflammatory responses. Together, these results show that non-productive binding of OGG1 to 8-oxoG in promoter sequences could be an epigenetic mechanism to modulate gene expression for a prompt innate immune response

8-Oxoguanine DNA glycosylase-1-mediated DNA repair is associated with Rho GTPase activation and α-smooth muscle actin polymerization

Reactive oxygen species (ROS) are activators of cell signaling and modify cellular molecules, including DNA. 8-Oxo-7,8-dihydroguanine (8-oxoG) is one of the prominent lesions in oxidatively damaged DNA, whose accumulation is causally linked to various diseases and aging processes, whereas its etiological relevance is unclear. 8-OxoG is repaired by the 8-oxoguanine DNA glycosylase-1 (OGG1)-initiated DNA base excision repair (BER) pathway. OGG1 binds free 8-oxoG and this complex functions as an activator of Ras family GTPases. Here we examined whether OGG1-initiated BER is associated with the activation of Rho GTPase and mediates changes in the cytoskeleton. To test this possibility, we induced OGG1- initiated BER in cultured cells and mouse lungs and used molecular approaches such as active Rho pull- down assays, siRNA ablation of gene expression, immune blotting, and microscopic imaging. We found that OGG1 physically interacts with Rho GTPase and, in the presence of 8-oxoG base, increases Rho–GTP levels in cultured cells and lungs, which mediates α-smooth muscle actin (α-SMA) polymerization into stress fibers and increases the level of α-SMA in insoluble cellular/tissue fractions. These changes were absent in cells lacking OGG1. These unexpected data and those showing that 8-oxoG repair is a lifetime process suggest that, via Rho GTPase, OGG1 could be involved in the cytoskeletal changes and organ remodeling observed in various chronic diseases

Mimotope ELISA for Detection of Broad Spectrum Antibody against Avian H5N1 Influenza Virus

Science and Technology Foundation of Fujian Province [2009YZ0002]; National Natural Science Foundation of China [30901077]; National High Technology Research and Development Program [2010AA022801]Background: We have raised a panel of broad spectrum neutralizing monoclonal antibodies against the highly pathogenic H5N1 avian influenza virus, which neutralize the infectivity of, and afford protection against infection by, most of the major genetic groups of the virus evolved since 1997. Peptide mimics reactive with one of these broad spectrum H5N1 neutralizing antibodies, 8H5, were identified from random phage display libraries. Method: The amino acid residues of the most reactive 12mer peptide, p125 (DTPLTTAALRLV), were randomly substituted to improve its mimicry of the natural 8H5 epitope. Result: 133 reactive peptides with unique amino acid sequences were identified from 5 sub-libraries of p125. Four residues (2,4,5.9) of the parental peptide were preserved among all the derived peptides and probably essential for 8H5 binding. These are interspersed among four other residues (1,3,8,10), which exhibit restricted substitution and probably could contribute to binding, and another four (6,7,11,12) which could be randomly substituted and probably are not essential for binding. One peptide, V-1b, derived by substituting 5 of the latter residues is the most reactive and has a binding constant of 3.16x10(-9) M, which is 38 fold higher than the affinity of the parental p125. Immunoassay produced with this peptide is specifically reactive with 8H5 but not also the other related broad spectrum H5N1 avian influenza virus neutralizing antibodies. Serum samples from 29 chickens infected with H5N1 avian influenza virus gave a positive result by this assay and those from 12 uninfected animals gave a negative test result. Conclusion: The immunoassay produced with the 12 mer peptide, V1-b, is specific for the natural 8H5 epitope and can be used for detection of antibody against the broad spectrum neutralization site of H5N1 avian influenza virus

Synergistic Air Pollutants and GHG Reduction Effect of Commercial Vehicle Electrification in Guangdong’s Public Service Sector

This paper aims to analyze the associated environment and climate benefits of electrification by comparing the air pollutant and CO2 emissions from the fuel cycle of battery electric commercial vehicles (BECVs) and internal combustion engine commercial vehicles (ICECVs) through a case study in Guangzhou Province. Five types of vehicles (i.e., electric buses, coaches, light-duty trucks, dump trucks, and waste haulers) used in the public service sector were selected for analysis, taking into account six development scenarios based on the prevalent ownership trends of electric vehicles and the energy system optimization process. The results reveal that an increase in commercial vehicle electrification in the public service sector will cause reductions of 19.3 × 103 tons, 0.5 × 103 tons, 9.5 × 103 tons, and 8.5 × 106 tons for NOx, PM2.5, VOCs, and CO2, respectively, from the base 2030 case (CS_II, the electrification rates of buses, coaches, light-duty trucks, dump trucks, and waste haulers will reach 100%, 26.5%, 15.4%, 24.0%, and 33.1%, and their power needs will be met by 24% coal, 18.4% gas, and 13.2% renewable power), but with a slight increase in SO2 emissions. With the further penetration of BECVs into the market, the emission reduction benefits for NOx, PM2.5, VOCs, and CO2 could be even more remarkable. Moreover, the benefit obtained from the optimization of the share of renewable energy is more noticeable for CO2 reduction than for air pollutant reduction. Prioritizing the electrification of light-duty trucks after completing bus electrification could be a potential solution for achieving ozone pollution control and lowering carbon emissions in Guangdong. In addition, these results can provide scientific support for the formulation or adjustment of advanced pollution mitigation and peaking carbon policies in Guangdong, as well as other regions of China

A Novel Form of Arginine-Chitosan as Nanoparticles Efficient for siRNA Delivery into Mouse Leukemia Cells

The modification of chitosan (CS) has greatly expanded its application in the field of medicine. In this study, low-molecular-weight chitosan was modified with arginine (Arg) by a simple method. The identification by the Fourier transform infrared spectra (FTIR) showed that Arg was successfully covalently attached to the CS. Interestingly, Arg-CS was identified as nanoparticles by atomic force microscopy (AFM) and transmission electron microscopy (TEM), whose particle size was 75.76 ± 12.07 nm based on Dynamic Light Scattering (DLS) characterization. Then, whether the prepared Arg-CS nanoparticles could encapsulate and deliver siRNA safely was investigated. Arg-CS was found to be able to encapsulate siRNAs in vitro via electrostatic interaction with siRNA; the Arg-CS/siRNA complex was safe for L1210 leukemia cells. Therefore, modification of chitosan by Arg produces novel nanoparticles to deliver siRNA into leukemia cells. This is the first time to identify Arg-CS as nanoparticles and explore their ability to deliver Rhoa siRNA into T-cell acute lymphoblastic leukemia (T-ALL) cells to advance therapies targeting Rhoa in the future

Changes of Soil Nutrients and Enzyme Activities in Calcareous Purple Soil Under Long-term Continuous Cropping for Tobacco Planting

【Objective】The problem of soil nutrient imbalance becomes more and more serious with the increase of tobacco planting years. The effects of continuous cropping of flue-cured tobacco on soil nutrients and enzyme activities in calcareous purple soil were systematically studied to provide data support for the improvement of soil fertility and the prevention and control of continuous cropping obstacles.【Method】In April 2021, typical plots of calcareous purple soil with different continuous cropping years (0 year, and 8, 10, 27, 33 years) in Zhaohua District, Guangyuan City were selected as the research objects, and the effects of long-term continuous cropping on soil nutrients, enzyme activities and the growth and development of flue-cured tobacco were analyzed.【Result】Long-term continuous cropping of flue-cured tobacco led to the decrease of soil organic matter, pH and alkaline nitrogen by 18.34%, 17.43% and 23.15%, while the contents of soil available phosphorus and available potassium increased by 124% and 54.55%, respectively. Long-term continuous cropping resulted in a decrease of 58.51%-91.28% in urease activity and a decrease of 29.14%-48.66% in sucrase activity in soil. The results of correlation analysis showed that soil sucrase activity was significantly negatively correlated with soil available phosphorus (P < 0.01). Soil β-glucosidase was significantly positively correlated with soil available potassium content (P < 0.01), while significantly negatively correlated with soil available phosphorus (P < 0.05). The soil urease activity was significantly positively correlated with soil pH (P < 0.01).【Conclusion】Long-term continuous cropping of flue-cured tobacco in calcareous purple soil has an inhibitory effect on soil nutrients and enzyme activities. Attention should be paid to the balanced application of nitrogen, phosphorus and potassium fertilizers, and organic fertilizer can be appropriately added to regulate the soil microenvironment to promote the transformation and absorption of nutrients