8-Oxoguanine （8-oxoG）, a critical mutagenic DNA lesion induced by reactive oxy- gen species, gives rise to a G·C→T·A transversion during replication and thereby must be repaired. The effects of explicit a...8-Oxoguanine （8-oxoG）, a critical mutagenic DNA lesion induced by reactive oxy- gen species, gives rise to a G·C→T·A transversion during replication and thereby must be repaired. The effects of explicit and implicit solvent molecules on the hydrolysis cleavage of N-Glycosidic bond in 8-oxo-7,8-dihydro-2＇-deoxyguanosine （8-oxo-dG） have been systematically clarified in the present work based upon two types of computational models. Detailed potential energy surface （PES） scans and full unconstraint optimizations for all the representative points on PESs were carried out at the B3LYP/6-31＋G（d） level of theory. The effect of implicit solvent was tested by single-point calculation at the SCRF/IEF-PCM model. The results illustrate that the direct hydrolysis model involving one explicit water molecule can’t provide a complete depiction of the hydrolysis process of 8-oxo-dG, attributed to the insufficiency of nucleophile activation and leaving group stabilization. The expansion hydrolysis model involving four explicit water molecules, however, facilitates discrete proton transfer and therefore produces smooth reaction surfaces for both the dissociative （SN1） and concerted （SN2） pathways. The presence of the implicit solvent substantially lowers all activation energies and the SN1 process is more favorable than the SN2 process. The data and insights present here agree well with the experimental results and have given out a baseline for the enzymatic deglycosylation reaction of 8-oxo-dG.展开更多
AIM： Nitrative and oxidative DNA damage such as 8-nitroguanine and 8-oxo-7,8-dihydro-2＇-deoxyguanosine （8-oxodG） formation has been implicated in initiation and/ or promotion of inflammation-mediated carcinogenesi...AIM： Nitrative and oxidative DNA damage such as 8-nitroguanine and 8-oxo-7,8-dihydro-2＇-deoxyguanosine （8-oxodG） formation has been implicated in initiation and/ or promotion of inflammation-mediated carcinogenesis. The aim of this study is to clarify whether these DNA lesions participate in the progression of intrahepatic cholangiocarcinoma. METHODS： We investigated the relation of the formation of 8-nitroguanine and 8-oxodG and the expression of hypoxia-inducible factor-1α （HIF-1α） with tumor invasion in 37 patients with intra-hepatic cholangiocarcinoma. RESULTS： Immunohistochemical analyses revealed that 8-nitroguanine and 8-oxodG formation occurred to a much greater extent in cancerous tissues than in non-cancerous tissues. HIF-1α could be detected in cancerous tissues in all patients, suggesting low oxygen tension in the tumors. HIF-1α expression was correlated with inducible niltric oxide synthase （iNOS） expression （r = 0.369 and P = 0.025） and 8-oxodG formation （r = 0.398 and P = 0.015）. Double immunofluorescence study revealed that iNOS and HIF-1α co-localized in cancerous tissues. Notably, the formation of 8-oxodG was correlated significantly with lymphatic invasion （r = 0.386 and P = 0.018）. Moreover, 8- nitroguanine and 8-oxodG in non-cancerous tissues were associated significantly with neural invasion （P = 0.042 and P = 0.026, respectively）. These results suggest that reciprocal activation between HIF-1α and iNOS mediates persistent DNA damage, which induces tumor invasiveness via mutations, resulting in poor prognosis. CONCLUSION： The formation of 8-nitroguanine and 8-oxodG plays an important role in multiple steps of genetic changes leading to tumor progression, including invasiveness.展开更多
BACKGROUND Shigella flexneri(S.flexneri)is a major pathogen causing acute intestinal infection,but the systematic oxidative damage incurred during the course of infection has not been investigated.AIM To investigate t...BACKGROUND Shigella flexneri(S.flexneri)is a major pathogen causing acute intestinal infection,but the systematic oxidative damage incurred during the course of infection has not been investigated.AIM To investigate the incurred systemic RNA oxidative damage and the diagnostic value of RNA oxidative metabolites during S.flexneri-induced intestinal infection.METHODS In this study,a Sprague-Dawley rat model of acute intestinal infection was established by oral gavage with S.flexneri strains.The changes in white blood cells(WBCs)and cytokine levels in blood and the inflammatory response in the colon were investigated.We also detected the RNA and DNA oxidation in urine and tissues.RESULTS S.flexneri infection induced an increase in WBCs,C-reactive protein,interleukin(IL)-6,IL-10,IL-1β,IL-4,IL-17a,IL-10,and tumor necrosis factorα(TNF-α)in blood.Of note,a significant increase in urinary 8-oxo-7,8-dihydroguanosine(8-oxo-Gsn),an important marker of total RNA oxidation,was detected after intestinal infection(P=0.03).The urinary 8-oxo-Gsn level returned to the baseline level after recovery from infection.In addition,the results of a correlation analysis showed that urinary 8-oxo-Gsn was positively correlated with the WBC count and the cytokines IL-6,TNF-α,IL-10,IL-1β,and IL-17α.Further detection of the oxidation in different tissues showed that S.flexneri infection induced RNA oxidative damage in the colon,ileum,liver,spleen,and brain.CONCLUSION Acute infection induced by S.flexneri causes increased RNA oxidative damage in various tissues(liver,spleen,and brain)and an increase of 8-oxo-Gsn,a urinary metabolite.Urinary 8-oxo-Gsn may be useful as a biomarker for evaluating the severity and prognosis of infection.展开更多
African swine fever virus(ASFV)is an important pathogen that causes a highly contagious and lethal disease in swine,for which neither a vaccine nor treatment is available.The DNA repair enzyme 8-oxoguanine DNA glycosy...African swine fever virus(ASFV)is an important pathogen that causes a highly contagious and lethal disease in swine,for which neither a vaccine nor treatment is available.The DNA repair enzyme 8-oxoguanine DNA glycosylase 1(OGG1),which excises the oxidative base lesion 8-oxo-7,8-dihydroguanine(8-oxoG),has been linked to the pathogenesis of different diseases associated with viral infections.However,the role of OGG1-base excision repair(BER)in ASFV infection has been poorly investigated.Our study aimed to characterize the alteration of host reactive oxygen species(ROS)and OGG1 and to analyse the role of OGG1 in ASFV infection.We found that ASFV infection induced high levels and dynamic changes in ROS and 8-oxoG and consistently increased the expression of OGG1.Viral yield,transcription level,and protein synthesis were reduced in ASFV-infected primary alveolar macrophages(PAMs)treated by TH5487 or SU0268 inhibiting OGG1.The expression of BER pathway associated proteins of ASFV was also suppressed in OGG1-inhibited PAMs.Furthermore,OGG1 was found to negatively regulate interferonβ(IFN-β)production during ASFV infection and IFN-βcould be activated by OGG1 inhibition with TH5487 and SU0268,which blocked OGG1 binding to 8-oxoG.Additionally,the interaction of OGG1 with viral MGF360-14-L protein could disturb IFN-βproduction to further affect ASFV replication.These results suggest that OGG1 plays the crucial role in successful viral infection and OGG1 inhibitors SU0268 or TH5487 could be used as antiviral agents for ASFV infection.展开更多
基金supported by the National Natural Science Foundation of China(21203153 and 21173151)Science&Technology Department(2011JY0136)+1 种基金Department of Education(12ZA174)of Sichuan ProvinceChina West Normal University(11B002)
文摘8-Oxoguanine （8-oxoG）, a critical mutagenic DNA lesion induced by reactive oxy- gen species, gives rise to a G·C→T·A transversion during replication and thereby must be repaired. The effects of explicit and implicit solvent molecules on the hydrolysis cleavage of N-Glycosidic bond in 8-oxo-7,8-dihydro-2＇-deoxyguanosine （8-oxo-dG） have been systematically clarified in the present work based upon two types of computational models. Detailed potential energy surface （PES） scans and full unconstraint optimizations for all the representative points on PESs were carried out at the B3LYP/6-31＋G（d） level of theory. The effect of implicit solvent was tested by single-point calculation at the SCRF/IEF-PCM model. The results illustrate that the direct hydrolysis model involving one explicit water molecule can’t provide a complete depiction of the hydrolysis process of 8-oxo-dG, attributed to the insufficiency of nucleophile activation and leaving group stabilization. The expansion hydrolysis model involving four explicit water molecules, however, facilitates discrete proton transfer and therefore produces smooth reaction surfaces for both the dissociative （SN1） and concerted （SN2） pathways. The presence of the implicit solvent substantially lowers all activation energies and the SN1 process is more favorable than the SN2 process. The data and insights present here agree well with the experimental results and have given out a baseline for the enzymatic deglycosylation reaction of 8-oxo-dG.
基金Supported by the Khon Kaen University Research Fund in Thailand Grants-in-Aid for Scientific Research from the Ministry of Education, Science, Sports and Culture of Japan
文摘AIM： Nitrative and oxidative DNA damage such as 8-nitroguanine and 8-oxo-7,8-dihydro-2＇-deoxyguanosine （8-oxodG） formation has been implicated in initiation and/ or promotion of inflammation-mediated carcinogenesis. The aim of this study is to clarify whether these DNA lesions participate in the progression of intrahepatic cholangiocarcinoma. METHODS： We investigated the relation of the formation of 8-nitroguanine and 8-oxodG and the expression of hypoxia-inducible factor-1α （HIF-1α） with tumor invasion in 37 patients with intra-hepatic cholangiocarcinoma. RESULTS： Immunohistochemical analyses revealed that 8-nitroguanine and 8-oxodG formation occurred to a much greater extent in cancerous tissues than in non-cancerous tissues. HIF-1α could be detected in cancerous tissues in all patients, suggesting low oxygen tension in the tumors. HIF-1α expression was correlated with inducible niltric oxide synthase （iNOS） expression （r = 0.369 and P = 0.025） and 8-oxodG formation （r = 0.398 and P = 0.015）. Double immunofluorescence study revealed that iNOS and HIF-1α co-localized in cancerous tissues. Notably, the formation of 8-oxodG was correlated significantly with lymphatic invasion （r = 0.386 and P = 0.018）. Moreover, 8- nitroguanine and 8-oxodG in non-cancerous tissues were associated significantly with neural invasion （P = 0.042 and P = 0.026, respectively）. These results suggest that reciprocal activation between HIF-1α and iNOS mediates persistent DNA damage, which induces tumor invasiveness via mutations, resulting in poor prognosis. CONCLUSION： The formation of 8-nitroguanine and 8-oxodG plays an important role in multiple steps of genetic changes leading to tumor progression, including invasiveness.
基金Supported by the National Key R&D Program of China,No.2018YFC2000300and CAMS Innovation Fund for Medical Sciences,No.2018-I2M-1-002.
文摘BACKGROUND Shigella flexneri(S.flexneri)is a major pathogen causing acute intestinal infection,but the systematic oxidative damage incurred during the course of infection has not been investigated.AIM To investigate the incurred systemic RNA oxidative damage and the diagnostic value of RNA oxidative metabolites during S.flexneri-induced intestinal infection.METHODS In this study,a Sprague-Dawley rat model of acute intestinal infection was established by oral gavage with S.flexneri strains.The changes in white blood cells(WBCs)and cytokine levels in blood and the inflammatory response in the colon were investigated.We also detected the RNA and DNA oxidation in urine and tissues.RESULTS S.flexneri infection induced an increase in WBCs,C-reactive protein,interleukin(IL)-6,IL-10,IL-1β,IL-4,IL-17a,IL-10,and tumor necrosis factorα(TNF-α)in blood.Of note,a significant increase in urinary 8-oxo-7,8-dihydroguanosine(8-oxo-Gsn),an important marker of total RNA oxidation,was detected after intestinal infection(P=0.03).The urinary 8-oxo-Gsn level returned to the baseline level after recovery from infection.In addition,the results of a correlation analysis showed that urinary 8-oxo-Gsn was positively correlated with the WBC count and the cytokines IL-6,TNF-α,IL-10,IL-1β,and IL-17α.Further detection of the oxidation in different tissues showed that S.flexneri infection induced RNA oxidative damage in the colon,ileum,liver,spleen,and brain.CONCLUSION Acute infection induced by S.flexneri causes increased RNA oxidative damage in various tissues(liver,spleen,and brain)and an increase of 8-oxo-Gsn,a urinary metabolite.Urinary 8-oxo-Gsn may be useful as a biomarker for evaluating the severity and prognosis of infection.
基金supported by the National Key Research and Development Program(Grant No.2021YFD1800101)the National Natural Science Foundation of China(Grant No.32072830)+5 种基金Gansu Provincial Major project for science and technology development(Grant No.20ZD7NA006)State Key Laboratory of Veterinary Etiological Biology,Lanzhou Veterinary Research Institute,Chinese Academy of Agricultural Sciences(Grant No.SKLVEB2020CGPY02)Natural Science Foundation of Gansu Province(Grant No.21JR1RA21421JR7RA018)Basic scientific research business expenses budget incremental project,Chinese Academy of Agricultural Sciences,Lanzhou Veterinary Research Institute(Grant Nos 1610312021002)National Agricultural Science and Technology Innovation Program(CAAS-ASTIP-2016-LVRI).
文摘African swine fever virus(ASFV)is an important pathogen that causes a highly contagious and lethal disease in swine,for which neither a vaccine nor treatment is available.The DNA repair enzyme 8-oxoguanine DNA glycosylase 1(OGG1),which excises the oxidative base lesion 8-oxo-7,8-dihydroguanine(8-oxoG),has been linked to the pathogenesis of different diseases associated with viral infections.However,the role of OGG1-base excision repair(BER)in ASFV infection has been poorly investigated.Our study aimed to characterize the alteration of host reactive oxygen species(ROS)and OGG1 and to analyse the role of OGG1 in ASFV infection.We found that ASFV infection induced high levels and dynamic changes in ROS and 8-oxoG and consistently increased the expression of OGG1.Viral yield,transcription level,and protein synthesis were reduced in ASFV-infected primary alveolar macrophages(PAMs)treated by TH5487 or SU0268 inhibiting OGG1.The expression of BER pathway associated proteins of ASFV was also suppressed in OGG1-inhibited PAMs.Furthermore,OGG1 was found to negatively regulate interferonβ(IFN-β)production during ASFV infection and IFN-βcould be activated by OGG1 inhibition with TH5487 and SU0268,which blocked OGG1 binding to 8-oxoG.Additionally,the interaction of OGG1 with viral MGF360-14-L protein could disturb IFN-βproduction to further affect ASFV replication.These results suggest that OGG1 plays the crucial role in successful viral infection and OGG1 inhibitors SU0268 or TH5487 could be used as antiviral agents for ASFV infection.
