Ischemia reperfusion injury is a major obstacle in liver resection and liver transplantation surgery.Understanding the mechanisms of liver ischemia reperfusion injury(IRI) and developing strategies to counteract this ...Ischemia reperfusion injury is a major obstacle in liver resection and liver transplantation surgery.Understanding the mechanisms of liver ischemia reperfusion injury(IRI) and developing strategies to counteract this injury will therefore reduce acute complications in hepatic resection and transplantation,as well as expanding the potential pool of usable donor grafts.The initial liver injury is initiated by reactive oxygen species which cause direct cellular injury and also activate a cascade of molecular mediators leading to microvascular changes,increased apoptosis and acute inflammatory changes with increased hepatocyte necrosis.Some adaptive pathways are activated during reperfusion that reduce the reperfusion injury.IRI involves a complex interplay between neutrophils,natural killer T-cells cells,CD4+ T cell subtypes,cytokines,nitric oxide synthases,haem oxygenase-1,survival kinases such as the signal transducer and activator of transcription,Phosphatidylinositol 3-kinases/Akt and nuclear factor κβ pathways.Transgenic animals,particularly genetic knockout models,have become a powerful tool at elucidating mechanisms of liver ischaemia reperfusion injury and are complementary to pharmacological studies.Targeted disruption of the protein at the genetic level is more specific and maintained than pharmacological inhibitors or stimulants of the same protein.This article reviews the evidence from knockout models of liver IRI about the cellular and molecular mechanisms underlying liver IRI.展开更多
The carcinogenic potential of iron in colorectal cancer(CRC) is not fully understood.Iron is able to undergo reduction and oxidation,making it important in many physiological processes.This inherent redox property of ...The carcinogenic potential of iron in colorectal cancer(CRC) is not fully understood.Iron is able to undergo reduction and oxidation,making it important in many physiological processes.This inherent redox property of iron,however,also renders it toxic when it is present in excess.Iron-mediated generation of reactive oxygen species via the Fenton reaction,if uncontrolled,may lead to cell damage as a result of lipid peroxidation and oxidative DNA and protein damage.This may promote carcinogenesis through increased genomic instability,chromosomal rearrangements as well as mutations of proto-oncogenes and tumour suppressor genes. Carcinogenesis is also affected by inflammation which is exacerbated by iron.Population studies indicate an association between high dietary iron intake and CRC risk.In this editorial,we examine the link betweeniron-induced oxidative stress and inflammation on the pathogenesis of CRC.展开更多
Iron is an essential trace metal in the human diet due to its obligate role in a number of metabolic processes. In the diet, iron is present in a number of different forms, generally described as haem （from haemoglob...Iron is an essential trace metal in the human diet due to its obligate role in a number of metabolic processes. In the diet, iron is present in a number of different forms, generally described as haem （from haemoglobin and myoglobin in animal tissue） and non-haem iron （including ferric oxides and salts, ferritin and lactoferrin）. This review describes the molecular mechanisms that co-ordinate the absorption of iron from the diet and its release into the circulation. While many components of the iron transport pathway have been elucidated, a number of key issues still remain to be resolved. Future work in this area will provide a clearer picture regarding the transcellular flux of iron and its regulation by dietary and humoral factors.展开更多
Heme oxygenase-1 （HO-1） has been recently identified as an endogenous signaling system in animals. In this study, HO-1 upregulation and its role in acquired salt tolerance （salinity acclimation） were investigated ...Heme oxygenase-1 （HO-1） has been recently identified as an endogenous signaling system in animals. In this study, HO-1 upregulation and its role in acquired salt tolerance （salinity acclimation） were investigated in wheat plants. We discovered that pretreatment with a low concentration of NaCl （25 mmol/L） not only led to the induction of HO-1 protein and gene expression, as well as enhanced HO activity, but also to a salinity acclimatory response thereafter. The effect is specific for HO-1, since the potent HO-1 inhibitor zinc protoporphyrin IX blocks the above cytoprotective actions, and the cytotoxic responses conferred by 200 mmol/L NaCl are reversed partially when HO-1 inducer hemin is added. Heme oxygenase catalytic product, carbon monoxide （CO） aqueous solution pretreatment, mimicked the salinity acclimatory responses. Meanwhile, the CO-triggered re-establishment of reactive oxygen species （ROS） homeostasis was mainly guaranteed by the induction of total and isozymatic activities, or corresponding transcripts of superoxide dismutase, ascorbate peroxidase, and cytosolic peroxidase （POD）, as well as the downregulation of NADPH oxidase expression and cell-wall POD activity. A requirement of hydrogen peroxide homeostasis for HO-1-mediated salinity acclimation was also discovered. Taken together, the above results suggest that the upregulation of HO-1 expression was responsible for the observed salinity acclimation through the regulation of ROS homeostasis.展开更多
Background： Mastitis, an infection caused by Gram-positive bacteria, produces udder inflammation and oxidative injury in milk-producing mammals. Toll-like receptor 2（TLR2） is important for host recognition of invad...Background： Mastitis, an infection caused by Gram-positive bacteria, produces udder inflammation and oxidative injury in milk-producing mammals. Toll-like receptor 2（TLR2） is important for host recognition of invading Grampositive microbes. Over-expression of TLR2 in transgenic dairy goats is a useful model for studying various aspects of infection with Gram-positive bacteria, in vivo.Methods： We over-expressed TLR2 in transgenic dairy goats. Pam3CSK4, a component of Gram-positive bacteria,triggered the TLR2 signal pathway by stimulating the monocytes-macrophages from the TLR2-positive transgenic goats, and induced over-expression of activator protein-1（AP-1）, phosphatidylinositol 3-kinase（PI3K） and transcription factor nuclear factor kappa B（NF-κB） and inflammation factors downstream of the signal pathway.Results： Compared with wild-type controls, measurements of various oxidative stress-related molecules showed that TLR2, when over-expressed in transgenic goat monocytes-macrophages, resulted in weak lipid damage, high level expression of anti-oxidative stress proteins, and significantly increased m RNA levels of transcription factor NF-E2-related factor-2（Nrf2） and the downstream gene, heme oxygenase-1（HO-1）. When Pam3CSK4 was used to stimulate ear tissue in vivo the HO-1 protein of the transgenic goats had a relatively high expression level.Conclusions： The results indicate that the oxidative injury in goats over-expressing TLR2 was reduced following Pam3CSK4 stimulation. The underlying mechanism for this reduction was increased expression of the anti-oxidation gene HO-1 by activation of the Nrf2 signal pathway.展开更多
Herpes simplex virus (HSV)-associated erythema multiforme (HAEM) is a recurrent disease characterized by the presence and expression of HSV DNA fragments in lesional skin. Our studies examined the mechanism of viral D...Herpes simplex virus (HSV)-associated erythema multiforme (HAEM) is a recurrent disease characterized by the presence and expression of HSV DNA fragments in lesional skin. Our studies examined the mechanism of viral DNA transport to the skin of HAEM patients. CD34+cells were isolated from the blood of normal subjects and HSV and HAEM patients during acute lesions and at quiescence. They were cultured with cytokines that favor their differentiation into Langerhans cells (LC) precursors (CD1a+/CD14-) and examined for HSV replication, HSV-induced cellular alterations, viral DNA fragmentation, and clearance. CD34+cells from all study groups were non-permissive for HSV replication but infection favored their differentiation into CD1a+/CD14-LC precursors and upregulated E-cadherin expression, thereby assisting LC targeting to the skin. Only HAEM patients had CD34+cells that retained viral DNA fragments, notably polymerase DNA, for at least 7 d of in vitro culture. The percentages of circulating CD34+(and CD34+/CLA+) cells were significantly higher in HAEM patients at the time of acute lesions. A similar increase was not seen for HSV patients. The data are the first report implicating CD34+cells in HAEM pathogenesis, likely by transporting HSV DNA fragments to lesional skin.展开更多
文摘Ischemia reperfusion injury is a major obstacle in liver resection and liver transplantation surgery.Understanding the mechanisms of liver ischemia reperfusion injury(IRI) and developing strategies to counteract this injury will therefore reduce acute complications in hepatic resection and transplantation,as well as expanding the potential pool of usable donor grafts.The initial liver injury is initiated by reactive oxygen species which cause direct cellular injury and also activate a cascade of molecular mediators leading to microvascular changes,increased apoptosis and acute inflammatory changes with increased hepatocyte necrosis.Some adaptive pathways are activated during reperfusion that reduce the reperfusion injury.IRI involves a complex interplay between neutrophils,natural killer T-cells cells,CD4+ T cell subtypes,cytokines,nitric oxide synthases,haem oxygenase-1,survival kinases such as the signal transducer and activator of transcription,Phosphatidylinositol 3-kinases/Akt and nuclear factor κβ pathways.Transgenic animals,particularly genetic knockout models,have become a powerful tool at elucidating mechanisms of liver ischaemia reperfusion injury and are complementary to pharmacological studies.Targeted disruption of the protein at the genetic level is more specific and maintained than pharmacological inhibitors or stimulants of the same protein.This article reviews the evidence from knockout models of liver IRI about the cellular and molecular mechanisms underlying liver IRI.
基金Supported by Grants from the Cancer Council of Western Australia and Fremantle Hospital Medical Research Foundation
文摘The carcinogenic potential of iron in colorectal cancer(CRC) is not fully understood.Iron is able to undergo reduction and oxidation,making it important in many physiological processes.This inherent redox property of iron,however,also renders it toxic when it is present in excess.Iron-mediated generation of reactive oxygen species via the Fenton reaction,if uncontrolled,may lead to cell damage as a result of lipid peroxidation and oxidative DNA and protein damage.This may promote carcinogenesis through increased genomic instability,chromosomal rearrangements as well as mutations of proto-oncogenes and tumour suppressor genes. Carcinogenesis is also affected by inflammation which is exacerbated by iron.Population studies indicate an association between high dietary iron intake and CRC risk.In this editorial,we examine the link betweeniron-induced oxidative stress and inflammation on the pathogenesis of CRC.
文摘Iron is an essential trace metal in the human diet due to its obligate role in a number of metabolic processes. In the diet, iron is present in a number of different forms, generally described as haem （from haemoglobin and myoglobin in animal tissue） and non-haem iron （including ferric oxides and salts, ferritin and lactoferrin）. This review describes the molecular mechanisms that co-ordinate the absorption of iron from the diet and its release into the circulation. While many components of the iron transport pathway have been elucidated, a number of key issues still remain to be resolved. Future work in this area will provide a clearer picture regarding the transcellular flux of iron and its regulation by dietary and humoral factors.
基金supported by the Program for New Century Excellent Talents in University(Grant No.NCET-07-0441)the Priority Academic Program Development of Jiangsu Higher Education Institutions,the Education Department of Jiangsu(Grant No.200910)+2 种基金the Technology Support Program in Jiangsu Province,China(Grant No.BE2010382)the National Natural Science Foundation of China(Grant No.30671248the Fundamental Research Funds for the Central Universities(Grant no.KYJ200912 and KYZ200905)
文摘Heme oxygenase-1 （HO-1） has been recently identified as an endogenous signaling system in animals. In this study, HO-1 upregulation and its role in acquired salt tolerance （salinity acclimation） were investigated in wheat plants. We discovered that pretreatment with a low concentration of NaCl （25 mmol/L） not only led to the induction of HO-1 protein and gene expression, as well as enhanced HO activity, but also to a salinity acclimatory response thereafter. The effect is specific for HO-1, since the potent HO-1 inhibitor zinc protoporphyrin IX blocks the above cytoprotective actions, and the cytotoxic responses conferred by 200 mmol/L NaCl are reversed partially when HO-1 inducer hemin is added. Heme oxygenase catalytic product, carbon monoxide （CO） aqueous solution pretreatment, mimicked the salinity acclimatory responses. Meanwhile, the CO-triggered re-establishment of reactive oxygen species （ROS） homeostasis was mainly guaranteed by the induction of total and isozymatic activities, or corresponding transcripts of superoxide dismutase, ascorbate peroxidase, and cytosolic peroxidase （POD）, as well as the downregulation of NADPH oxidase expression and cell-wall POD activity. A requirement of hydrogen peroxide homeostasis for HO-1-mediated salinity acclimation was also discovered. Taken together, the above results suggest that the upregulation of HO-1 expression was responsible for the observed salinity acclimation through the regulation of ROS homeostasis.
基金supported by grants from National Transgenic Creature Breeding Grand Project(2014ZX08008-005)Chinese Universities Scientific Fund(2014BH032)Natural Science Foundation of China(31501953, 31471352, 31471400 and 31171380)
文摘Background： Mastitis, an infection caused by Gram-positive bacteria, produces udder inflammation and oxidative injury in milk-producing mammals. Toll-like receptor 2（TLR2） is important for host recognition of invading Grampositive microbes. Over-expression of TLR2 in transgenic dairy goats is a useful model for studying various aspects of infection with Gram-positive bacteria, in vivo.Methods： We over-expressed TLR2 in transgenic dairy goats. Pam3CSK4, a component of Gram-positive bacteria,triggered the TLR2 signal pathway by stimulating the monocytes-macrophages from the TLR2-positive transgenic goats, and induced over-expression of activator protein-1（AP-1）, phosphatidylinositol 3-kinase（PI3K） and transcription factor nuclear factor kappa B（NF-κB） and inflammation factors downstream of the signal pathway.Results： Compared with wild-type controls, measurements of various oxidative stress-related molecules showed that TLR2, when over-expressed in transgenic goat monocytes-macrophages, resulted in weak lipid damage, high level expression of anti-oxidative stress proteins, and significantly increased m RNA levels of transcription factor NF-E2-related factor-2（Nrf2） and the downstream gene, heme oxygenase-1（HO-1）. When Pam3CSK4 was used to stimulate ear tissue in vivo the HO-1 protein of the transgenic goats had a relatively high expression level.Conclusions： The results indicate that the oxidative injury in goats over-expressing TLR2 was reduced following Pam3CSK4 stimulation. The underlying mechanism for this reduction was increased expression of the anti-oxidation gene HO-1 by activation of the Nrf2 signal pathway.
文摘Herpes simplex virus (HSV)-associated erythema multiforme (HAEM) is a recurrent disease characterized by the presence and expression of HSV DNA fragments in lesional skin. Our studies examined the mechanism of viral DNA transport to the skin of HAEM patients. CD34+cells were isolated from the blood of normal subjects and HSV and HAEM patients during acute lesions and at quiescence. They were cultured with cytokines that favor their differentiation into Langerhans cells (LC) precursors (CD1a+/CD14-) and examined for HSV replication, HSV-induced cellular alterations, viral DNA fragmentation, and clearance. CD34+cells from all study groups were non-permissive for HSV replication but infection favored their differentiation into CD1a+/CD14-LC precursors and upregulated E-cadherin expression, thereby assisting LC targeting to the skin. Only HAEM patients had CD34+cells that retained viral DNA fragments, notably polymerase DNA, for at least 7 d of in vitro culture. The percentages of circulating CD34+(and CD34+/CLA+) cells were significantly higher in HAEM patients at the time of acute lesions. A similar increase was not seen for HSV patients. The data are the first report implicating CD34+cells in HAEM pathogenesis, likely by transporting HSV DNA fragments to lesional skin.
