Role of p53 in silibinin-mediated inhibition of ultraviolet B radiation-induced DNA damage, inflammation and skin carcinogenesis.

PubMed

Rigby, Cynthia M; Roy, Srirupa; Deep, Gagan; Guillermo-Lagae, Ruth; Jain, Anil K; Dhar, Deepanshi; Orlicky, David J; Agarwal, Chapla; Agarwal, Rajesh

2017-01-01

Non-melanoma skin cancers (NMSC) are a growing problem given that solar ultraviolet B (UVB) radiation exposure is increasing most likely due to depletion of the atmospheric ozone layer and lack of adequate sun protection. Better preventive methods are urgently required to reduce UV-caused photodamage and NMSC incidence. Earlier, we have reported that silibinin treatment activates p53 and reduces photodamage and NMSC, both in vitro and in vivo; but whether silibinin exerts its protective effects primarily through p53 remains unknown. To address this question, we generated p53 heterozygous (p53 +/- ) and p53 knockout (p53 -/- ) mice on SKH-1 hairless mouse background, and assessed silibinin efficacy in both short- and long-term UVB exposure experiments. In the chronic UVB-exposed skin tumorigenesis study, compared to p53 +/+ mice, p53 +/- mice developed skin tumors earlier and had higher tumor number, multiplicity and volume. Silibinin topical treatment significantly reduced the tumor number, multiplicity and volume in p53 +/+ mice but silibinin' protective efficacy was significantly compromised in p53 +/- mice. Additionally, silibinin treatment failed to inhibit precursor skin cancer lesions in p53 -/- mice but improved the survival of the mice. In short-term studies, silibinin application accelerated the removal of UVB-induced DNA damage in p53 +/+ mice while its efficacy was partially compromised in p53 -/- mice. Interestingly, silibinin treatment also inhibited the UVB-induced inflammatory markers in skin tissue. These results further confirmed that absence of the p53 allele predisposes mice to photodamage and photocarcinogenesis, and established that silibinin mediates its protection against UVB-induced photodamage, inflammation and photocarcinogenesis partly through p53 activation. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Role of p53 in silibinin-mediated inhibition of ultraviolet B radiation-induced DNA damage, inflammation and skin carcinogenesis

PubMed Central

Rigby, Cynthia M.; Roy, Srirupa; Deep, Gagan; Guillermo-Lagae, Ruth; Jain, Anil K.; Dhar, Deepanshi; Orlicky, David J.; Agarwal, Chapla; Agarwal, Rajesh

2017-01-01

Non-melanoma skin cancers (NMSC) are a growing problem given that solar ultraviolet B (UVB) radiation exposure is increasing most likely due to depletion of the atmospheric ozone layer and lack of adequate sun protection. Better preventive methods are urgently required to reduce UV-caused photodamage and NMSC incidence. Earlier, we have reported that silibinin treatment activates p53 and reduces photodamage and NMSC, both in vitro and in vivo; but whether silibinin exerts its protective effects primarily through p53 remains unknown. To address this question, we generated p53 heterozygous (p53+/−) and p53 knockout (p53−/−) mice on SKH-1 hairless mouse background, and assessed silibinin efficacy in both short- and long-term UVB exposure experiments. In the chronic UVB-exposed skin tumorigenesis study, compared to p53+/+ mice, p53+/− mice developed skin tumors earlier and had higher tumor number, multiplicity and volume. Silibinin topical treatment significantly reduced the tumor number, multiplicity and volume in p53+/+ mice but silibinin’ protective efficacy was significantly compromised in p53+/− mice. Additionally, silibinin treatment failed to inhibit precursor skin cancer lesions in p53−/− mice but improved the survival of the mice. In short-term studies, silibinin application accelerated the removal of UVB-induced DNA damage in p53+/+ mice while its efficacy was partially compromised in p53−/− mice. Interestingly, silibinin treatment also inhibited the UVB-induced inflammatory markers in skin tissue. These results further confirmed that absence of the p53 allele predisposes mice to photodamage and photocarcinogenesis, and established that silibinin mediates its protection against UVB-induced photodamage, inflammation and photocarcinogenesis partly through p53 activation. PMID:27729375

Different susceptibility of cells of porcine skin and internal organs to ultraviolet A-induced breaking of nuclear DNA.

PubMed

Brozyna, Anna; Chwirot, Barbara W

2005-01-01

There is a continuously growing interest in medical applications of ultraviolet radiation (UV-A and long-wavelength UV-B) especially for laser surgery, phototherapy and photodiagnostics of human internal organs. UV-B and UV-A radiation is potentially mutagenic, however, there has been very little information published to date concerning the significance of possible deleterious action of such photons on cells of internal tissues. The aim of this study is to compare the sensitivities of skin cells to those of internal organs upon exposure to UV-A. To assess this sensitivity we have determined the UV-A dose-dependent frequency of nuclear DNA breaks detected with the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling (TUNEL) technique. The materials for the study were macroscopic samples of porcine skin, colon and esophagus. The UV-A dose ranged from 0.1 to 1000 mJ/cm2, which is similar to doses received by cells in regions examined with laser-induced fluorescence or by cells surrounding areas subject to a laser ablation. To reduce the influence of DNA repair processes the tissue samples were kept at a low temperature during the irradiation and were deep frozen immediately after completing the irradiation procedure. The cells of the internal organs are much more susceptible to UV-A-induced breaking of DNA than the skin cells. The percentage fractions and the spatial distributions of the damaged cells and the characteristics of the UV-A dose dependence seem to vary by type of internal organ.

Differential responses to high- and low-dose ultraviolet-B stress in tobacco Bright Yellow-2 cells

PubMed Central

Takahashi, Shinya; Kojo, Kei H.; Kutsuna, Natsumaro; Endo, Masaki; Toki, Seiichi; Isoda, Hiroko; Hasezawa, Seiichiro

2015-01-01

Ultraviolet (UV)-B irradiation leads to DNA damage, cell cycle arrest, growth inhibition, and cell death. To evaluate the UV-B stress–induced changes in plant cells, we developed a model system based on tobacco Bright Yellow-2 (BY-2) cells. Both low-dose UV-B (low UV-B: 740 J m−2) and high-dose UV-B (high UV-B: 2960 J m−2) inhibited cell proliferation and induced cell death; these effects were more pronounced at high UV-B. Flow cytometry showed cell cycle arrest within 1 day after UV-B irradiation; neither low- nor high-UV-B–irradiated cells entered mitosis within 12 h. Cell cycle progression was gradually restored in low-UV-B–irradiated cells but not in high-UV-B–irradiated cells. UV-A irradiation, which activates cyclobutane pyrimidine dimer (CPD) photolyase, reduced inhibition of cell proliferation by low but not high UV-B and suppressed high-UV-B–induced cell death. UV-B induced CPD formation in a dose-dependent manner. The amounts of CPDs decreased gradually within 3 days in low-UV-B–irradiated cells, but remained elevated after 3 days in high-UV-B–irradiated cells. Low UV-B slightly increased the number of DNA single-strand breaks detected by the comet assay at 1 day after irradiation, and then decreased at 2 and 3 days after irradiation. High UV-B increased DNA fragmentation detected by the terminal deoxynucleotidyl transferase dUTP nick end labeling assay 1 and 3 days after irradiation. Caffeine, an inhibitor of ataxia telangiectasia mutated (ATM) and ataxia telangiectasia and Rad3-related (ATR) checkpoint kinases, reduced the rate of cell death in high-UV-B–irradiated cells. Our data suggest that low-UV-B–induced CPDs and/or DNA strand-breaks inhibit DNA replication and proliferation of BY-2 cells, whereas larger contents of high-UV-B–induced CPDs and/or DNA strand-breaks lead to cell death. PMID:25954287

Is UV-induced DNA damage greater at higher elevation?

PubMed

Wang, Qing-Wei; Hidema, Jun; Hikosaka, Kouki

2014-05-01

• Although ultraviolet radiation (UV) is known to have negative effects on plant growth, there has been no direct evidence that plants growing at higher elevations are more severely affected by ultraviolet-B (UV-B) radiation, which is known to increase with elevation. We examined damage to DNA, a primary target of UV-B, in the widespread species Polygonum sachalinense (Fallopia sachalinensis) and Plantago asiatica at two elevations.• We sampled leaves of both species at 300 and 1700 m above sea level every 2 h for 11 d across the growing season and determined the level of cyclobutane pyrimidine dimer (CPD), a major product of UV damage to DNA.• The CPD level was significantly influenced by the time of day, date, elevation, and their interactions in both species. The CPD level tended to be higher at noon or on sunny days. DNA damage was more severe at 1700 m than at 300 m: on average, 8.7% greater at high elevation in P. asiatica and 7.8% greater in P. sachalinense Stepwise multiple regression analysis indicated that the CPD level was explained mainly by UV-B and had no significant relationship with other environmental factors such as temperature and photosynthetically active radiation.• UV-induced DNA damage in plants is greater at higher elevations. © 2014 Botanical Society of America, Inc.

Silymarin Protects Epidermal Keratinocytes from Ultraviolet Radiation-Induced Apoptosis and DNA Damage by Nucleotide Excision Repair Mechanism

PubMed Central

Katiyar, Santosh K.; Mantena, Sudheer K.; Meeran, Syed M.

2011-01-01

Solar ultraviolet (UV) radiation is a well recognized epidemiologic risk factor for melanoma and non-melanoma skin cancers. This observation has been linked to the accumulation of UVB radiation-induced DNA lesions in cells, and that finally lead to the development of skin cancers. Earlier, we have shown that topical treatment of skin with silymarin, a plant flavanoid from milk thistle (Silybum marianum), inhibits photocarcinogenesis in mice; however it is less understood whether chemopreventive effect of silymarin is mediated through the repair of DNA lesions in skin cells and that protect the cells from apoptosis. Here, we show that treatment of normal human epidermal keratinocytes (NHEK) with silymarin blocks UVB-induced apoptosis of NHEK in vitro. Silymarin reduces the amount of UVB radiation-induced DNA damage as demonstrated by reduced amounts of cyclobutane pyrimidine dimers (CPDs) and as measured by comet assay, and that ultimately may lead to reduced apoptosis of NHEK. The reduction of UV radiation-induced DNA damage by silymarin appears to be related with induction of nucleotide excision repair (NER) genes, because UV radiation-induced apoptosis was not blocked by silymarin in NER-deficient human fibroblasts. Cytostaining and dot-blot analysis revealed that silymarin repaired UV-induced CPDs in NER-proficient fibroblasts from a healthy individual but did not repair UV-induced CPD-positive cells in NER-deficient fibroblasts from patients suffering from xeroderma pigmentosum complementation-A disease. Similarly, immunohistochemical analysis revealed that silymarin did not reduce the number of UVB-induced sunburn/apoptotic cells in the skin of NER-deficient mice, but reduced the number of sunburn cells in their wild-type counterparts. Together, these results suggest that silymarin exert the capacity to reduce UV radiation-induced DNA damage and, thus, prevent the harmful effects of UV radiation on the genomic stability of epidermal cells. PMID:21731736

Ultraviolet-Induced Decrease in Integration of Haemophilus influenzae Transforming Deoxyribonucleic Acid in Sensitive and Resistant Cells

PubMed Central

Muhammed, Amir; Setlow, Jane K.

1970-01-01

The decrease in integration of transforming deoxyribonucleic acid (DNA) caused by ultraviolet irradiation of the DNA was found to be independent of the presence or absence of excision repair in the recipient cell. Much of the ultraviolet-induced inhibition of integration resulted from the presence in the transforming DNA of pyrimidine dimers, as judged by the photoreactivability of the inhibition with yeast photoreactivating enzyme. The inhibition of integration made only a small contribution to the inactivation of transforming ability of the DNA by ultraviolet radiation. PMID:5308769

An Overview of Ultraviolet B Radiation-Induced Skin Cancer Chemoprevention by Silibinin.

PubMed

Kumar, Rahul; Deep, Gagan; Agarwal, Rajesh

2015-06-01

Skin cancer incidences are rising worldwide, and one of the major causative factors is excessive exposure to solar ultraviolet radiation (UVR). Annually, ~5 million skin cancer patients are treated in United States, mostly with nonmelanoma skin cancer (NMSC), which is also frequent in other Western countries. As sunscreens do not provide adequate protection against deleterious effects of UVR, additional and alternative chemoprevention strategies are urgently needed to reduce skin cancer burden. Over the last couple of decades, extensive research has been conducted to understand the molecular basis of skin carcinogenesis, and to identifying novel agents which could be useful in the chemoprevention of skin cancer. In this regard, several natural non-toxic compounds have shown promising efficacy in preventing skin carcinogenesis at initiation, promotion and progression stages, and are considered important in better management of skin cancer. Consistent with this, we and others have studied and established the notable efficacy of natural flavonolignan silibinin against UVB-induced skin carcinogenesis. Extensive pre-clinical animal and cell culture studies report strong anti-inflammatory, anti-oxidant, DNA damage repair, immune-modulatory and anti-proliferative properties of silibinin. Molecular studies have identified that silibinin targets pleotropic signaling pathways including mitogenic, cell cycle, apoptosis, autophagy, p53, NF-κB, etc. Overall, the skin cancer chemopreventive potential of silibinin is well supported by comprehensive mechanistic studies, suggesting its greater use against UV-induced cellular damages and photocarcinogenesis.

An Overview of Ultraviolet B Radiation-Induced Skin Cancer Chemoprevention by Silibinin

PubMed Central

Kumar, Rahul; Deep, Gagan; Agarwal, Rajesh

2015-01-01

Skin cancer incidences are rising worldwide, and one of the major causative factors is excessive exposure to solar ultraviolet radiation (UVR). Annually, ~5 million skin cancer patients are treated in United States, mostly with nonmelanoma skin cancer (NMSC), which is also frequent in other Western countries. As sunscreens do not provide adequate protection against deleterious effects of UVR, additional and alternative chemoprevention strategies are urgently needed to reduce skin cancer burden. Over the last couple of decades, extensive research has been conducted to understand the molecular basis of skin carcinogenesis, and to identifying novel agents which could be useful in the chemoprevention of skin cancer. In this regard, several natural non-toxic compounds have shown promising efficacy in preventing skin carcinogenesis at initiation, promotion and progression stages, and are considered important in better management of skin cancer. Consistent with this, we and others have studied and established the notable efficacy of natural flavonolignan silibinin against UVB-induced skin carcinogenesis. Extensive pre-clinical animal and cell culture studies report strong anti-inflammatory, anti-oxidant, DNA damage repair, immune-modulatory and anti-proliferative properties of silibinin. Molecular studies have identified that silibinin targets pleotropic signaling pathways including mitogenic, cell cycle, apoptosis, autophagy, p53, NF-κB, etc. Overall, the skin cancer chemopreventive potential of silibinin is well supported by comprehensive mechanistic studies, suggesting its greater use against UV-induced cellular damages and photocarcinogenesis. PMID:26097804

Spatial Positioning of All 24 Chromosomes in the Lymphocytes of Six Subjects: Evidence of Reproducible Positioning and Spatial Repositioning following DNA Damage with Hydrogen Peroxide and Ultraviolet B

PubMed Central

Kandukuri, Lakshmi; Quadri, Ameer; Becerra, Victor; Simpson, Joe Leigh

2015-01-01

The higher-order organization of chromatin is well-established, with chromosomes occupying distinct positions within the interphase nucleus. Chromatin is susceptible to, and constantly assaulted by both endogenous and exogenous threats. However, the effects of DNA damage on the spatial topology of chromosomes are hitherto, poorly understood. This study investigates the organization of all 24 human chromosomes in lymphocytes from six individuals prior to- and following in-vitro exposure to genotoxic agents: hydrogen peroxide and ultraviolet B. This study is the first to report reproducible distinct hierarchical radial organization of chromosomes with little inter-individual differences between subjects. Perturbed nuclear organization was observed following genotoxic exposure for both agents; however a greater effect was observed for hydrogen peroxide including: 1) More peripheral radial organization; 2) Alterations in the global distribution of chromosomes; and 3) More events of chromosome repositioning (18 events involving 10 chromosomes vs. 11 events involving 9 chromosomes for hydrogen peroxide and ultraviolet B respectively). Evidence is provided of chromosome repositioning and altered nuclear organization following in-vitro exposure to genotoxic agents, with notable differences observed between the two investigated agents. Repositioning of chromosomes following genotoxicity involved recurrent chromosomes and is most likely part of the genomes inherent response to DNA damage. The variances in nuclear organization observed between the two agents likely reflects differences in mobility and/or decondensation of chromatin as a result of differences in the type of DNA damage induced, chromatin regions targeted, and DNA repair mechanisms. PMID:25756782

Spatial positioning of all 24 chromosomes in the lymphocytes of six subjects: evidence of reproducible positioning and spatial repositioning following DNA damage with hydrogen peroxide and ultraviolet B.

PubMed

Ioannou, Dimitrios; Kandukuri, Lakshmi; Quadri, Ameer; Becerra, Victor; Simpson, Joe Leigh; Tempest, Helen G

2015-01-01

The higher-order organization of chromatin is well-established, with chromosomes occupying distinct positions within the interphase nucleus. Chromatin is susceptible to, and constantly assaulted by both endogenous and exogenous threats. However, the effects of DNA damage on the spatial topology of chromosomes are hitherto, poorly understood. This study investigates the organization of all 24 human chromosomes in lymphocytes from six individuals prior to- and following in-vitro exposure to genotoxic agents: hydrogen peroxide and ultraviolet B. This study is the first to report reproducible distinct hierarchical radial organization of chromosomes with little inter-individual differences between subjects. Perturbed nuclear organization was observed following genotoxic exposure for both agents; however a greater effect was observed for hydrogen peroxide including: 1) More peripheral radial organization; 2) Alterations in the global distribution of chromosomes; and 3) More events of chromosome repositioning (18 events involving 10 chromosomes vs. 11 events involving 9 chromosomes for hydrogen peroxide and ultraviolet B respectively). Evidence is provided of chromosome repositioning and altered nuclear organization following in-vitro exposure to genotoxic agents, with notable differences observed between the two investigated agents. Repositioning of chromosomes following genotoxicity involved recurrent chromosomes and is most likely part of the genomes inherent response to DNA damage. The variances in nuclear organization observed between the two agents likely reflects differences in mobility and/or decondensation of chromatin as a result of differences in the type of DNA damage induced, chromatin regions targeted, and DNA repair mechanisms.

Redundancy of mammalian Y family DNA polymerases in cellular responses to genomic DNA lesions induced by ultraviolet light

PubMed Central

Jansen, Jacob G.; Temviriyanukul, Piya; Wit, Niek; Delbos, Frédéric; Reynaud, Claude-Agnès; Jacobs, Heinz; de Wind, Niels

2014-01-01

Short-wave ultraviolet light induces both mildly helix-distorting cyclobutane pyrimidine dimers (CPDs) and severely distorting (6–4) pyrimidine pyrimidone photoproducts ((6–4)PPs). The only DNA polymerase (Pol) that is known to replicate efficiently across CPDs is Polη, a member of the Y family of translesion synthesis (TLS) DNA polymerases. Phenotypes of Polη deficiency are transient, suggesting redundancy with other DNA damage tolerance pathways. Here we performed a comprehensive analysis of the temporal requirements of Y-family Pols ι and κ as backups for Polη in (i) bypassing genomic CPD and (6–4)PP lesions in vivo, (ii) suppressing DNA damage signaling, (iii) maintaining cell cycle progression and (iv) promoting cell survival, by using mouse embryonic fibroblast lines with single and combined disruptions in these Pols. The contribution of Polι is restricted to TLS at a subset of the photolesions. Polκ plays a dominant role in rescuing stalled replication forks in Polη-deficient mouse embryonic fibroblasts, both at CPDs and (6–4)PPs. This dampens DNA damage signaling and cell cycle arrest, and results in increased survival. The role of relatively error-prone Pols ι and κ as backups for Polη contributes to the understanding of the mutator phenotype of xeroderma pigmentosum variant, a syndrome caused by Polη defects. PMID:25170086

Jatropha curcas leaf and bark fractions protect against ultraviolet radiation-B induced DNA damage in human peripheral blood lymphocytes.

PubMed

Sundari, J; Selvaraj, R; Rajendra Prasad, N; Elumalai, R

2013-11-01

The present study is conducted to investigate the antioxidant potential of Jatropha curcas root bark extract (RB4 fraction) and leaf extract (L1 fraction), and to study their effects on UVB-radiation-induced DNA damage in cultured human blood lymphocytes. In this study, J. curcas showed strong antioxidant property in different free radical scavenging systems. Both the fractions effectively scavenged hydroxyl (OH), superoxide anion (O₂(·-)), 1,1-diphenyl-2-picrylhydrazyl (DPPH·) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid radical cation (ABTS(·+)) in a concentration-dependent manner. The IC₅₀ (Inhibitory Concentration 50) values of J. curcas fractions were compared to standard ascorbic acid used in this study. The antioxidant potential of a compound was directly proportional to the photoprotective effect. In this study, human peripheral blood lymphocytes (HPBL) were exposed to UVB-radiation and there was an increase in comet attributes (% tail DNA, tail length, tail movement and Olive tail moment). Jatropha curcas RB4 fraction and L1 fraction treatment before UVB-irradiation significantly decreased the % tail DNA, tail length, tail moment and Olive tail moment in irradiated HPBL. These results suggested that J. curcas exhibited strong antioxidant property and RB4 and L1 fractions protected UVB-radiation-induced DNA damage in HPBL. Copyright © 2013 Elsevier B.V. All rights reserved.

Ursolic Acid-Regulated Energy Metabolism—Reliever or Propeller of Ultraviolet-Induced Oxidative Stress and DNA Damage?

PubMed Central

Lee, Yuan-Hao; Sun, Youping; Glickman, Randolph D.

2014-01-01

Ultraviolet (UV) light is a leading cause of diseases, such as skin cancers and cataracts. A main process mediating UV-induced pathogenesis is the production of reactive oxygen species (ROS). Excessive ROS levels induce the formation of DNA adducts (e.g., pyrimidine dimers) and result in stalled DNA replication forks. In addition, ROS promotes phosphorylation of tyrosine kinase-coupled hormone receptors and alters downstream energy metabolism. With respect to the risk of UV-induced photocarcinogenesis and photodamage, the antitumoral and antioxidant functions of natural compounds become important for reducing UV-induced adverse effects. One important question in the field is what determines the differential sensitivity of various types of cells to UV light and how exogenous molecules, such as phytochemicals, protect normal cells from UV-inflicted damage while potentiating tumor cell death, presumably via interaction with intracellular target molecules and signaling pathways. Several endogenous molecules have emerged as possible players mediating UV-triggered DNA damage responses. Specifically, UV activates the PIKK (phosphatidylinositol 3-kinase-related kinase) family members, which include DNA-PKcs, ATM (ataxia telangiectasia mutated) and mTOR (mammalian target of rapamycin), whose signaling can be affected by energy metabolism; however, it remains unclear to what extent the activation of hormone receptors regulates PIKKs and whether this crosstalk occurs in all types of cells in response to UV. This review focuses on proteomic descriptions of the relationships between cellular photosensitivity and the phenotypic expression of the insulin/insulin-like growth receptor. It covers the cAMP-dependent pathways, which have recently been shown to regulate the DNA repair machinery through interactions with the PIKK family members. Finally, this review provides a strategic illustration of how UV-induced mitogenic activity is modulated by the insulin sensitizer, ursolic

Rapamycin Protects Skin Fibroblasts from Ultraviolet B-Induced Photoaging by Suppressing the Production of Reactive Oxygen Species.

PubMed

Qin, Dengke; Ren, Runjian; Jia, Chuanlong; Lu, Yongzhou; Yang, Qingjian; Chen, Liang; Wu, Xinyuan; Zhu, Jingjing; Guo, Yu; Yang, Ping; Zhou, Yiqun; Zhu, Ningwen; Bi, Bo; Liu, Tianyi

2018-01-01

Ultraviolet B (UVB) irradiation alters multiple molecular pathways in the skin, thereby inducing skin photoaging. Murine dermal fibroblasts (MDFs) were subjected to a series of 4 sub-cytotoxic UVB doses (120 mJ/cm2), resulting in changes in cell shape, DNA damage, cell cycle arrest, extracellular matrix variations, reactive oxygen species (ROS) generation, and alterations in major intracellular antioxidant and cellular autophagy levels. Rapamycin (RAPA) is a new macrolide immunosuppressive agent that is primarily used in oncology, cardiology, and transplantation medicine and has been found to extend the lifespan of genetically heterogeneous mice. Several studies have shown that RAPA may have anti-aging effects in cells and organisms. Thus, in this study, we explored the effects and mechanisms of RAPA against the photoaging process using a well-established cellular photoaging model. We developed a stress-induced premature senescence (SIPS) model through repeated exposure of MDFs to ultraviolet B (UVB) irradiation. The cells were cultured in the absence or presence of RAPA for 48 h. Senescent phenotypes were assessed by examining cell viability, cell morphology, senescence-associated β-galactosidase (SA-β-gal) expression, cell cycle progression, intracellular ROS production, matrix metalloproteinase (MMP) synthesis and degradation, extracellular matrix (ECM) component protein expression, alterations in major intracellular antioxidant levels, and the cellular autophagy level. Compared with the UVB group, pretreatment with RAPA (5 µM) significantly decreased the staining intensity and percentage of SA-β-gal-positive cells and preserved the elongated cell shape. Moreover, cells pretreated with RAPA showed inhibition of the reduction in the type I collagen content by blocking the UVB-induced upregulation of MMP expression. RAPA also decreased photoaging cell cycle arrest and downregulated p53 and p21 expression. RAPA application significantly attenuated irradiation-induced

[Effect of long-wave ultraviolet light (UV-A) and medium-wave ultraviolet rays (UV-B) on human skin. Critical comparison].

PubMed

Raab, W

1980-04-15

When discussing the effects of ultraviolet radiation on human skin, one should carefully distinguish between the long wave ultraviolet light (UV-A) and the short wave radiations (UV-B and UV-C). Ultraviolet A induces immediate pigmentation but, if high energies are applied, a permanent pigmentation is elicited. This type of ultraviolet A-induced pigmentation has been called "spontaneous" pigmentation as no erythematous reaction is necessary to induce or accelerate melanine formation. Ultraviolet B provokes erythema and consecutive pigmentation. Upon chronic exposure, ultraviolet B causes the wellknown actinic damage of the skin and even provokes carcinoma. With exposures to the sunlight (global radiation), one should be most careful. The public must be informed extensively about the dangers of excessive sunbaths. The use of artificial "suns" with spectra between 260 and 400 nm is limited as it may cause the same type of damage as the global radiation. An exact schedule for use of artificial lamps is strongly recommended. After one cycle of exposures, an interruption is necessary until the next cycle of irradiations may start. Upon continual use for tanning of the skin, artificial lamps may provoke irreversible damage of the skin. Radiation sources with emission spectra of wavelengths between 315 and 400 nm exclusively are well suited for the induction of skin pigmentation (cosmetic use). Potent radiation such as UVASUN systems provoke a "pleasant" permanent pigmentation after exposures for less than one hour. The use of ultraviolet A (UV-A) does not carry any risk for the human skin.

Cell damage caused by ultraviolet B radiation in the desert cyanobacterium Phormidium tenue and its recovery process.

PubMed

Wang, Gaohong; Deng, Songqiang; Liu, Jiafeng; Ye, Chaoran; Zhou, Xiangjun; Chen, Lanzhou

2017-10-01

Phormidium tenue, a cyanobacterium that grows in the topsoil of biological soil crusts (BSCs), has the highest recovery rate among desert crust cyanobacteria after exposure to ultraviolet B (UV-B) radiation. However, the mechanism underlying its recovery process is unclear. To address this issue, we measured chlorophyll a fluorescence, generation of reactive oxygen species (ROS), lipid peroxidation, and repair of DNA breakage in P. tenue following exposure to UV-B. We found that UV-B radiation at all doses tested reduced photosynthesis and induced cell damage in P. tenue. However, P. tenue responded to UV-B radiation by rapidly reducing photosynthetic activity, which protects the cell by leaking less ROS. Antioxidant enzymes, DNA damage repair systems, and UV absorbing pigments were then induced to mitigate the damage caused by UV-B radiation. The addition of exogenous antioxidant chemicals ascorbate and N-acetylcysteine also mitigated the harmful effects caused by UV-B radiation and enhanced the recovery process. These chemicals could aid in the resistance of P. tenue to the exposure of intense UV-B radiation in desertified areas when inoculated onto the sand surface to form artificial algal crusts. Copyright © 2017. Published by Elsevier Inc.

Mushroom extract inhibits ultraviolet B-induced cellular senescence in human keratinocytes.

PubMed

Chong, Zhao; Matsuo, Haruka; Kuroda, Mai; Yamashita, Shuntaro; Parajuli, Gopal Prasad; Manandhar, Hira Kaji; Shimizu, Kuniyoshi; Katakura, Yoshinori

2018-06-02

Mushrooms possess various bioactivities and are used as nutritional supplements and medicinal products. Twenty-nine bioactive components have been extracted recently from mushrooms grown in Nepal. In this study, we evaluated the ability of these mushroom extracts to augment SIRT1, a mammalian SIR2 homologue localized in cytosol and nuclei. We established a system for screening food ingredients that augment the SIRT1 promoter in HaCaT cells, and identified a SIRT1-augmenting mushroom extract (number 28, Trametes versicolor). UVB irradiation induced cellular senescence in HaCaT cells, as evidenced by increased activity and expression of cellular senescence markers including senescence-associated β-galactosidase, p21, p16, phosphorylated p38, and γH2AX. Results clearly showed that the mushroom extract (No. 28) suppressed the ultraviolet B irradiation-induced cellular senescence in HaCaT cells possibly through augmenting SIRT1 expression.

Ultraviolet-B- and ozone-induced biochemical changes in antioxidant enzymes of Arabidopsis thaliana.

PubMed Central

Rao, M V; Paliyath, G; Ormrod, D P

1996-01-01

Earlier studies with Arabidopsis thaliana exposed to ultraviolet B (UV-B) and ozone (O3) have indicated the differential responses of superoxide dismutase and glutathione reductase. In this study, we have investigated whether A. thaliana genotype Landsberg erecta and its flavonoid-deficient mutant transparent testa (tt5) is capable of metabolizing UV-B- and O3-induced activated oxygen species by invoking similar antioxidant enzymes. UV-B exposure preferentially enhanced guaiacol-peroxidases, ascorbate peroxidase, and peroxidases specific to coniferyl alcohol and modified the substrate affinity of ascorbate peroxidase. O3 exposure enhanced superoxide dismutase, peroxidases, glutathione reductase, and ascorbate peroxidase to a similar degree and modified the substrate affinity of both glutathione reductase and ascorbate peroxidase. Both UV-B and O3 exposure enhanced similar Cu,Zn-superoxide dismutase isoforms. New isoforms of peroxidases and ascorbate peroxidase were synthesized in tt5 plants irradiated with UV-B. UV-B radiation, in contrast to O3, enhanced the activated oxygen species by increasing membrane-localized NADPH-oxidase activity and decreasing catalase activities. These results collectively suggest that (a) UV-B exposure preferentially induces peroxidase-related enzymes, whereas O3 exposure invokes the enzymes of superoxide dismutase/ascorbate-glutathione cycle, and (b) in contrast to O3, UV-B exposure generated activated oxygen species by increasing NADPH-oxidase activity. PMID:8587977

REPRESSOR OF ULTRAVIOLET-B PHOTOMORPHOGENESIS function allows efficient phototropin mediated ultraviolet-B phototropism in etiolated seedlings.

PubMed

Vanhaelewyn, Lucas; Schumacher, Paolo; Poelman, Dirk; Fankhauser, Christian; Van Der Straeten, Dominique; Vandenbussche, Filip

2016-11-01

Ultraviolet B (UV-B) light is a part of the solar radiation which has significant effects on plant morphology, even at low doses. In Arabidopsis, many of these morphological changes have been attributed to a specific UV-B receptor, UV resistance locus 8 (UVR8). Recent findings showed that next to phototropin regulated phototropism, UVR8 mediated signaling is able of inducing directional bending towards UV-B light in etiolated seedlings of Arabidopsis, in a phototropin independent manner. In this study, kinetic analysis of phototropic bending was used to evaluate the relative contribution of each of these pathways in UV-B mediated phototropism. Diminishing UV-B light intensity favors the importance of phototropins. Molecular and genetic analyses suggest that UV-B is capable of inducing phototropin signaling relying on phototropin kinase activity and regulation of NPH3. Moreover, enhanced UVR8 responses in the UV-B hypersensitive rup1rup2 mutants interferes with the fast phototropin mediated phototropism. Together the data suggest that phototropins are the most important receptors for UV-B induced phototropism in etiolated seedlings, and a RUP mediated negative feedback pathway prevents UVR8 signaling to interfere with the phototropin dependent response. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Whey peptides prevent chronic ultraviolet B radiation-induced skin aging in melanin-possessing male hairless mice.

PubMed

Kimura, Yoshiyuki; Sumiyoshi, Maho; Kobayashi, Toshiya

2014-01-01

Whey proteins or peptides exhibit various actions, including an antioxidant action, an anticancer action, and a protective action against childhood asthma and atopic syndrome. The effects of orally administered whey peptides (WPs) on chronic ultraviolet B (UVB) radiation-induced cutaneous changes, including changes in cutaneous thickness, elasticity, wrinkle formation, etc., have not been examined. In this study, we studied the preventive effects of WPs on cutaneous aging induced by chronic UVB irradiation in melanin-possessing male hairless mice (HRM). UVB (36-180 mJ/cm(2)) was irradiated to the dorsal area for 17 wk in HRM, and the measurements of cutaneous thickness and elasticity in UVB irradiated mice were performed every week. WPs (200 and 400 mg/kg, twice daily) were administered orally for 17 wk. WPs inhibited the increase in cutaneous thickness, wrinkle formation, and melanin granules and the reduction in cutaneous elasticity associated with photoaging. Furthermore, it has been reported that UVB irradiation-induced skin aging is closely associated with the increase in expression of matrix metalloproteinase (MMP), vascular endothelial growth factor (VEGF), Ki-67-, and 8-hydroxy-2'-deoxyguanosine (8-OHdG)-positive cells. WPs also prevented increases in the expression of MMP-2 and pro-MMP-9, VEGF, and Ki-67- and 8-OHdG-positive cells induced by chronic UVB irradiation. It was found that WPs prevent type IV collagen degradation, angiogenesis, proliferation, and DNA damage caused by UVB irradiation. Overall, these results demonstrate the considerable benefit of WPs for protection against solar UV-irradiated skin aging as a supplemental nutrient.

Protective effect of cerium ion against ultraviolet B radiation-induced water stress in soybean seedlings.

PubMed

Mao, Chun Xia; Chen, Min Min; Wang, Lei; Zou, Hua; Liang, Chan Juan; Wang, Li Hong; Zhou, Qing

2012-06-01

Effects of cerium ion (Ce(III)) on water relations of soybean seedlings (Glycine max L.) under ultraviolet B radiation (UV-B, 280-320 nm) stress were investigated under laboratory conditions. UV-B radiation not only affected the contents of two osmolytes (proline, soluble sugar) in soybean seedlings, but also inhibited the transpiration in soybean seedlings by decreasing the stomatal density and conductance. The two effects caused the inhibition in the osmotic and metabolic absorption of water, which decreased the water content and the free water/bound water ratio. Obviously, UV-B radiation led to water stress, causing the decrease in the photosynthesis in soybean seedlings. The pretreatment with 20 mg L(-1) Ce(III) could alleviate UV-B-induced water stress by regulating the osmotic and metabolic absorption of water in soybean seedlings. The alleviated effect caused the increase in the photosynthesis and the growth of soybean seedlings. It is one of the protective effect mechanisms of Ce(III) against the UV-B radiation-induced damage to plants.

Protective effect of 3,4-dihydroxybenzoic acid isolated from Cladophora wrightiana Harvey against ultraviolet B radiation-induced cell damage in human HaCaT keratinocytes.

PubMed

Cha, Ji Won; Piao, Mei Jing; Kim, Ki Cheon; Zheng, Jian; Yao, Cheng Wen; Hyun, Chang Lim; Kang, Hee Kyoung; Yoo, Eun Sook; Koh, Young Sang; Lee, Nam Ho; Ko, Mi Hee; Hyun, Jin Won

2014-03-01

The aim of the present study was to elucidate the protective properties of 3,4-dihydroxybenzoic acid (DBA) isolated from Cladophora wrightiana Harvey (a green alga) against ultraviolet B (UVB)-induced damage to human HaCaT keratinocytes. DBA exhibited scavenging actions against the 1,1-diphenyl-2-picrylhydrazyl radical, the superoxide anion, and the hydroxyl radical. Furthermore, DBA decreased the levels of intracellular reactive oxygen species generated by hydrogen peroxide or UVB treatment of the cells. DBA also decreased the UVB-augmented levels of phospho-histone H2A.X and the extent of comet tail formation, which are both indications of DNA damage. In addition, the compound safeguarded keratinocytes from UVB-induced injury by reversing the production of apoptotic bodies, overturning the disruption of mitochondrial membrane potential, increasing the expression of the anti-apoptotic protein, B-cell lymphoma 2, and decreasing the expression of the pro-apoptotic proteins, Bcl-2-associated X and cleaved caspase-3. Taken together, these results demonstrate that DBA isolated from a green alga protects human keratinocytes against UVB-induced oxidative stress and apoptosis.

Psoralen-ultraviolet A treatment with Psoralen-ultraviolet B therapy in the treatment of psoriasis.

PubMed

Ahmed Asim, Sadaf; Ahmed, Sitwat; Us-Sehar, Najam

2013-05-01

To compare the conventional psoralen-ultraviolet A treatment with psoralen-ultraviolet B therapy in the treatment of psoriasis. We studied 50 patients of plaque type psoriasis who were selected to receive either conventional psoralen-ultraviolet A or psoralen-ultraviolet B treatment. There was no significant difference between the two treatment groups in the number of patients whose skin cleared of psoriasis or the number of exposures required for clearance. Profile of side effects and disease status was also similar after three months of follow up. Psoralen-ultraviolet B treatment is as effective as conventional psoralen-ultraviolet A in the treatment of psoriasis. Further long term studies are needed to assess the safety of psoralen-ultraviolet B.

A decrease in cyclin B1 levels leads to polyploidization in DNA damage-induced senescence.

PubMed

Kikuchi, Ikue; Nakayama, Yuji; Morinaga, Takao; Fukumoto, Yasunori; Yamaguchi, Naoto

2010-05-04

Adriamycin, an anthracycline antibiotic, has been used for the treatment of various types of tumours. Adriamycin induces at least two distinct types of growth repression, such as senescence and apoptosis, in a concentration-dependent manner. Cellular senescence is a condition in which cells are unable to proliferate further, and senescent cells frequently show polyploidy. Although abrogation of cell division is thought to correlate with polyploidization, the mechanisms underlying induction of polyploidization in senescent cells are largely unclear. We wished, therefore, to explore the role of cyclin B1 level in polyploidization of Adriamycin-induced senescent cells. A subcytotoxic concentration of Adriamycin induced polyploid cells having the features of senescence, such as flattened and enlarged cell shape and activated beta-galactosidase activity. In DNA damage-induced senescent cells, the levels of cyclin B1 were transiently increased and subsequently decreased. The decrease in cyclin B1 levels occurred in G2 cells during polyploidization upon treatment with a subcytotoxic concentration of Adriamycin. In contrast, neither polyploidy nor a decrease in cyclin B1 levels was induced by treatment with a cytotoxic concentration of Adriamycin. These results suggest that a decrease in cyclin B1 levels is induced by DNA damage, resulting in polyploidization in DNA damage-induced senescence.

Using DNA origami nanostructures to determine absolute cross sections for UV photon-induced DNA strand breakage.

PubMed

Vogel, Stefanie; Rackwitz, Jenny; Schürman, Robin; Prinz, Julia; Milosavljević, Aleksandar R; Réfrégiers, Matthieu; Giuliani, Alexandre; Bald, Ilko

2015-11-19

We have characterized ultraviolet (UV) photon-induced DNA strand break processes by determination of absolute cross sections for photoabsorption and for sequence-specific DNA single strand breakage induced by photons in an energy range from 6.50 to 8.94 eV. These represent the lowest-energy photons able to induce DNA strand breaks. Oligonucleotide targets are immobilized on a UV transparent substrate in controlled quantities through attachment to DNA origami templates. Photon-induced dissociation of single DNA strands is visualized and quantified using atomic force microscopy. The obtained quantum yields for strand breakage vary between 0.06 and 0.5, indicating highly efficient DNA strand breakage by UV photons, which is clearly dependent on the photon energy. Above the ionization threshold strand breakage becomes clearly the dominant form of DNA radiation damage, which is then also dependent on the nucleotide sequence.

Psoralen-ultraviolet A treatment with Psoralen-ultraviolet B therapy in the treatment of psoriasis

PubMed Central

Ahmed Asim, Sadaf; Ahmed, Sitwat; us-Sehar, Najam

2013-01-01

Objective: To compare the conventional psoralen-ultraviolet A treatment with psoralen-ultraviolet B therapy in the treatment of psoriasis. Methodology: We studied 50 patients of plaque type psoriasis who were selected to receive either conventional psoralen-ultraviolet A or psoralen-ultraviolet B treatment. Results: There was no significant difference between the two treatment groups in the number of patients whose skin cleared of psoriasis or the number of exposures required for clearance. Profile of side effects and disease status was also similar after three months of follow up. Conclusion: Psoralen-ultraviolet B treatment is as effective as conventional psoralen-ultraviolet A in the treatment of psoriasis. Further long term studies are needed to assess the safety of psoralen-ultraviolet B. PMID:24353623

Leptin deficiency-induced obesity exacerbates ultraviolet B radiation-induced cyclooxygenase-2 expression and cell survival signals in ultraviolet B-irradiated mouse skin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Som D.; Katiyar, Santosh K., E-mail: skatiyar@uab.ed; Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294

Obesity has been implicated in several inflammatory diseases and in different types of cancer. Chronic inflammation induced by exposure to ultraviolet (UV) radiation has been implicated in various skin diseases, including melanoma and nonmelanoma skin cancers. As the relationship between obesity and susceptibility to UV radiation-caused inflammation is not clearly understood, we assessed the role of obesity on UVB-induced inflammation, and mediators of this inflammatory response, using the genetically obese (leptin-deficient) mouse model. Leptin-deficient obese (ob/ob) mice and wild-type counterparts (C57/BL6 mice) were exposed to UVB radiation (120 mJ/cm{sup 2}) on alternate days for 1 month. The mice were thenmore » euthanized and skin samples collected for analysis of biomarkers of inflammatory responses using immunohistochemistry, western blotting, ELISA and real-time PCR. Here, we report that the levels of inflammatory responses were higher in the UVB-exposed skin of the ob/ob obese mice than those in the UVB-exposed skin of the wild-type non-obese mice. The levels of UVB-induced cyclooxygenase-2 expression, prostaglandin-E{sub 2} production, proinflammatory cytokines (i.e., tumor necrosis factor-alpha, interleukin-1beta, interleukin-6), and proliferating cell nuclear antigen and cell survival signals (phosphatidylinositol-3-kinase and p-Akt-Ser{sup 473}) were higher in the skin of the ob/ob obese mice than the those in skin of their wild-type non-obese counterparts. Compared with the wild-type non-obese mice, the leptin-deficient obese mice also exhibited greater activation of NF-kappaB/p65 and fewer apoptotic cells in the UVB-irradiated skin. Our study suggests for the first time that obesity in mice is associated with greater susceptibility to UVB-induced inflammatory responses and, therefore, obesity may increase susceptibility to UVB-induced inflammation-associated skin diseases, including the risk of skin cancer.« less

Flavonoids Derived from Abelmoschus esculentus Attenuates UV-B Induced Cell Damage in Human Dermal Fibroblasts Through Nrf2-ARE Pathway.

PubMed

Patwardhan, Juilee; Bhatt, Purvi

2016-05-01

Ultraviolet-B (UV-B) radiation is a smaller fraction of the total radiation reaching the Earth but leads to extensive damage to the deoxyribonucleic acid (DNA) and other biomolecules through formation of free radicals altering redox homeostasis of the cell. Abelmoschus esculentus (okra) has been known in Ayurveda as antidiabetic, hypolipidemic, demulscent, antispasmodic, diuretic, purgative, etc. The aim of this study is to evaluate the protective effect of flavonoids from A. esculentus against UV-B-induced cell damage in human dermal fibroblasts. UV-B protective activity of ethyl acetate (EA) fraction of okra was studied against UV-B-induced cytotoxicity, antioxidant regulation, oxidative DNA damage, intracellular reactive oxygen species (ROS) generation, apoptotic morphological changes, and regulation of heme oxygenase-1 (HO-1) gene through nuclear factor E2-related factor 2-antioxidant response element (Nrf2-ARE) pathway. Flavonoid-rich EA fraction depicted a significant antioxidant potential also showing presence of rutin. Pretreatment of cells with EA fraction (10-30 μg/ml) prevented UV-B-induced cytotoxicity, depletion of endogenous enzymatic antioxidants, oxidative DNA damage, intracellular ROS production, apoptotic changes, and overexpression of Nrf2 and HO-1. Our study demonstrated for the 1(st) time that EA fraction of okra may reduce oxidative stress through Nrf2-ARE pathway as well as through endogenous enzymatic antioxidant system. These results suggested that flavonoids from okra may be considered as potential UV-B protective agents and may also be formulated into herbal sunscreen for topical application. Flavonoid-enriched ethyl acetate (EA) fraction from A. esculentus protected against ultraviolet-B (UV-B)-induced oxidative DNA damageEA fraction prevented UV-B-induced cytotoxicity, depletion of endogenous enzymatic antioxidants, and intracellular reactive oxygen species productionEA fraction could reduce oxidative stress through the Nrf2-ARE

[Effect of flavin adenine dinucleotide on ultraviolet B induced damage in cultured human corneal epithelial cells].

PubMed

Sakamoto, Asuka; Nakamura, Masatsugu

2012-01-01

This study evaluated the effects of flavin adenine dinucleotide (FAD) on ultraviolet B (UV-B)-induced damage in cultured human corneal epithelial (HCE-T) cells. The cultured HCE-T cells were treated with 0.003125-0.05% FAD before exposure to 80 mJ/cm2 UV-B. Cell viability was measured 24 h after UV-B irradiation using the MTS assay. Reactive oxygen species (ROS) were detected 30 min after UV-B irradiation using 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate acetyl ester. Apoptosis was evaluated 4 h after UV-B irradiation in the caspase-3/7 activity assay. UV-B irradiation reduced cell viability and stimulated ROS production and caspase-3/7 activity in HCE-T cells. Pretreatment of UV-B irradiated HCE-T cells with FAD significantly attenuated cell viability reduction and inhibited the stimulation of both ROS production and caspase-3/7 activity due to UV-B exposure compared with those with vehicle (0% FAD). These results clarified that FAD inhibits ROS-mediated apoptosis by UV-B irradiation in HCE-T cells and suggest that FAD may be effective as a radical scavenger in UV-B-induced corneal damage.

Survival and SOS response induction in ultraviolet B irradiated Escherichia coli cells with defective repair mechanisms.

PubMed

Prada Medina, Cesar Augusto; Aristizabal Tessmer, Elke Tatjana; Quintero Ruiz, Nathalia; Serment-Guerrero, Jorge; Fuentes, Jorge Luis

2016-06-01

Purpose In this paper, the contribution of different genes involved in DNA repair for both survival and SOS induction in Escherichia coli mutants exposed to ultraviolet B radiation (UVB, [wavelength range 280-315 nm]) was evaluated. Materials and methods E. coli strains defective in uvrA, oxyR, recO, recN, recJ, exoX, recB, recD or xonA genes were used to determine cell survival. All strains also had the genetic sulA::lacZ fusion, which allowed for the quantification of SOS induction through the SOS Chromotest. Results Five gene products were particularly important for survival, as follows: UvrA > RecB > RecO > RecJ > XonA. Strains defective in uvrA and recJ genes showed elevated SOS induction compared with the wild type, which remained stable for up to 240 min after UVB-irradiation. In addition, E. coli strains carrying the recO or recN mutation showed no SOS induction. Conclusions The nucleotide excision and DNA recombination pathways were equally used to repair UVB-induced DNA damage in E. coli cells. The sulA gene was not turned off in strains defective in UvrA and RecJ. RecO protein was essential for processing DNA damage prior to SOS induction. In this study, the roles of DNA repair proteins and their contributions to the mechanisms that induce SOS genes in E. coli are proposed.

Duck Enteritis Virus Glycoprotein D and B DNA Vaccines Induce Immune Responses and Immunoprotection in Pekin Ducks

PubMed Central

Zhao, Yan; Cao, Yongsheng; Cui, Lihong; Ma, Bo; Mu, Xiaoyu; Li, Yanwei; Zhang, Zhihui; Li, Dan; Wei, Wei; Gao, Mingchun; Wang, Junwei

2014-01-01

DNA vaccine is a promising strategy for protection against virus infection. However, little is known on the efficacy of vaccination with two plasmids for expressing the glycoprotein D (gD) and glycoprotein B (gB) of duck enteritis virus (DEV) in inducing immune response and immunoprotection against virulent virus infection in Pekin ducks. In this study, two eukaryotic expressing plasmids of pcDNA3.1-gB and pcDNA3.1-gD were constructed. Following transfection, the gB and gD expressions in DF1 cells were detected. Groups of ducks were vaccinated with pcDNA3.1-gB and/or pcDNA3.1-gD, and boosted with the same vaccine on day 14 post primary vaccination. We found that intramuscular vaccinations with pcDNA3.1-gB and/or pcDNA3.1-gD, but not control plasmid, stimulated a high frequency of CD4+ and CD8+ T cells in Pekin ducks, particularly with both plasmids. Similarly, vaccination with these plasmids, particularly with both plasmids, promoted higher levels of neutralization antibodies against DEV in Pekin ducks. More importantly, vaccination with both plasmids significantly reduced the virulent DEV-induced mortality in Pekin ducks. Our data indicated that vaccination with plasmids for expressing both gB and gD induced potent cellular and humoral immunity against DEV in Pekin ducks. Therefore, this vaccination strategy may be used for the prevention of DEV infection in Pekin ducks. PMID:24736466

Duck enteritis virus glycoprotein D and B DNA vaccines induce immune responses and immunoprotection in Pekin ducks.

PubMed

Zhao, Yan; Cao, Yongsheng; Cui, Lihong; Ma, Bo; Mu, Xiaoyu; Li, Yanwei; Zhang, Zhihui; Li, Dan; Wei, Wei; Gao, Mingchun; Wang, Junwei

2014-01-01

DNA vaccine is a promising strategy for protection against virus infection. However, little is known on the efficacy of vaccination with two plasmids for expressing the glycoprotein D (gD) and glycoprotein B (gB) of duck enteritis virus (DEV) in inducing immune response and immunoprotection against virulent virus infection in Pekin ducks. In this study, two eukaryotic expressing plasmids of pcDNA3.1-gB and pcDNA3.1-gD were constructed. Following transfection, the gB and gD expressions in DF1 cells were detected. Groups of ducks were vaccinated with pcDNA3.1-gB and/or pcDNA3.1-gD, and boosted with the same vaccine on day 14 post primary vaccination. We found that intramuscular vaccinations with pcDNA3.1-gB and/or pcDNA3.1-gD, but not control plasmid, stimulated a high frequency of CD4+ and CD8+ T cells in Pekin ducks, particularly with both plasmids. Similarly, vaccination with these plasmids, particularly with both plasmids, promoted higher levels of neutralization antibodies against DEV in Pekin ducks. More importantly, vaccination with both plasmids significantly reduced the virulent DEV-induced mortality in Pekin ducks. Our data indicated that vaccination with plasmids for expressing both gB and gD induced potent cellular and humoral immunity against DEV in Pekin ducks. Therefore, this vaccination strategy may be used for the prevention of DEV infection in Pekin ducks.

Coenzyme Q0 Enhances Ultraviolet B-Induced Apoptosis in Human Estrogen Receptor-Positive Breast (MCF-7) Cancer Cells.

PubMed

Wang, Hui-Min; Yang, Hsin-Ling; Thiyagarajan, Varadharajan; Huang, Tzu-Hsiang; Huang, Pei-Jane; Chen, Ssu-Ching; Liu, Jer-Yuh; Hsu, Li-Sung; Chang, Hsueh-Wei; Hseu, You-Cheng

2017-09-01

Coenzyme Q 0 (CoQ 0 ; 2,3-dimethoxy-5-methyl-1,4-benzoquinone), a major active constituent of Antrodia camphorata, has been shown to inhibit human triple-negative breast cancer (MDA-MB-231) cells through induction of apoptosis and cell-cycle arrest. Ecological studies have suggested a possible association between ultraviolet B (UVB) radiation and reduction in the risk of breast cancer. However, the underlying mechanism of the combination of CoQ 0 and UVB in human estrogen receptor-positive breast cancer (MCF-7) remains unclear. In this study, the possible effect of CoQ 0 on inducing apoptosis in MCF-7 cells under exposure to low-dose UVB (0.05 J/cm 2 ) has been investigated. CoQ 0 treatment (0-35 µM, for 24-72 hours) inhibits moderately the growth of breast cancer MCF-7 cells, and the cell viability was significantly decreased when the cells were pretreated with UVB irradiation. It was noted that there was a remarkable accumulation of subploid cells, the so-called sub-G1 peak, in CoQ 0 -treated cells by using flow cytometric analysis, which suggests that the viability reduction observed after treatment may result from apoptosis induction in MCF-7 cells. CoQ 0 caused an elevation of reactive oxygen species, as indicated by dichlorofluorescein fluorescence, and UVB pretreatment significantly increased CoQ 0 -induced reactive oxygen species generation in MCF-7 cells. In addition, cells were exposed to CoQ 0 , and the induction of DNA damage was evaluated by single-cell gel electrophoresis (comet assay). CoQ 0 -induced DNA damage was remarkably enhanced by UVB pretreatment. Furthermore, CoQ 0 induced apoptosis in MCF-7 cells, which was associated with PARP degradation, Bcl-2/Bax dysregulation, and p53 expression as shown by western blot. Collectively, these findings suggest that CoQ 0 might be an important supplemental agent for treating patients with breast cancer.

Effect of DNA-injuring agents on B. stearothermophilus. Report 1. High resistance of B. stearothermophilus to N-nitroso-N-methylurea, ultraviolet and gamma radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gainullina, S.M.; Gumanova, A.V.; Vinogradova, N.A.

1978-01-01

The effects of DNA-attacking agents on thermophilic microorganisms were investigated. Bacillus stearothermophilus were treated with N-nitroso-N-methylurea, ultraviolet radiation or gamma radiation. Survival curves were plotted.

ULTRAVIOLET PROTECTIVE PIGMENTS AND DNA DIMER INDUCTION AS RESPONSES TO ULTRAVIOLET RADIATION

EPA Science Inventory

Life on Earth has evolved adaptations to many environmental stresses over the epochs. One consistent stress has been exposure to ultraviolet (UV) radiation. The most basic effect of UV radiation on biological systems is damage to DNA. In response to UV radiation organisms have ad...

Alleviation of Ultraviolet B-Induced Photodamage by Coffea arabica Extract in Human Skin Fibroblasts and Hairless Mouse Skin

PubMed Central

Wu, Po-Yuan; Huang, Chi-Chang; Chu, Yin; Huang, Ya-Han; Lin, Ping; Liu, Yu-Han; Wen, Kuo-Ching; Lin, Chien-Yih; Hsu, Mei-Chich; Chiang, Hsiu-Mei

2017-01-01

Coffea arabica extract (CAE) containing 48.3 ± 0.4 mg/g of chlorogenic acid and a trace amount of caffeic acid was found to alleviate photoaging activity in human skin fibroblasts. In this study, polyphenol-rich CAE was investigated for its antioxidant and antiinflammatory properties, as well as for its capability to alleviate ultraviolet B (UVB)-induced photodamage in BALB/c hairless mice. The results indicated that 500 μg/mL of CAE exhibited a reducing power of 94.7%, ferrous ion chelating activity of 46.4%, and hydroxyl radical scavenging activity of 20.3%. The CAE dose dependently reduced UVB-induced reactive oxygen species (ROS) generation in fibroblasts. Furthermore, CAE inhibited the UVB-induced expression of cyclooxygenase-2 and p-inhibitor κB, and the translocation of nuclear factor-kappa B (NF-κB) to the nucleus of fibroblasts. In addition, CAE alleviated UVB-induced photoaging and photodamage in BALB/c hairless mice by restoring the collagen content and reduced UVB-induced epidermal hyperplasia. CAE also inhibited UVB-induced NF-κB, interleukin-6, and matrix metalloproteinase-1 expression in the hairless mouse skin. The results indicated that CAE exhibits antiphotodamage activity by inhibiting UV-induced oxidative stress and inflammation. Therefore, CAE is a candidate for use in antioxidant, antiinflammatory, and antiphotodamage products. PMID:28387707

Cytochrome P450 2A13 enhances the sensitivity of human bronchial epithelial cells to aflatoxin B1-induced DNA damage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xuejiao; Jiaojiang District Center for Disease Control and Prevention, 518 Jingdong Rd., Taizhou 318000; Zhang, Zhan

Cytochrome P450 2A13 (CYP2A13) mainly expresses in human respiratory system and mediates the metabolic activation of aflatoxin B1 (AFB1). Our previous study suggested that CYP2A13 could increase the cytotoxic and apoptotic effects of AFB1 in immortalized human bronchial epithelial cells (BEAS-2B). However, the role of CYP2A13 in AFB1-induced DNA damage is unclear. Using BEAS-2B cells that stably express CYP2A13 (B-2A13), CYP1A2 (B-1A2), and CYP2A6 (B-2A6), we compared their effects in AFB1-induced DNA adducts, DNA damage, and cell cycle changes. BEAS-2B cells that were transfected with vector (B-vector) were used as a control. The results showed that AFB1 (5–80 nM) dose-more » and time-dependently induced DNA damage in B-2A13 cells. AFB1 at 10 and 80 nM significantly augmented this effect in B-2A13 and B-1A2 cells, respectively. B-2A6 cells showed no obvious DNA damage, similar to B-vector cells and the vehicle control. Similarly, compared with B-vector, B-1A2 or B-2A6 cells, B-2A13 cells showed more sensitivity in AFB1-induced γH2AX expression, DNA adduct 8-hydroxy-deoxyguanosine formation, and S-phase cell-cycle arrest. Furthermore, AFB1 activated the proteins related to DNA damage responses, such as ATM, ATR, Chk2, p53, BRCA1, and H2AX, rather than the proteins related to DNA repair. These effects could be almost completely inhibited by 100 μM nicotine (a substrate of CYP2A13) or 1 μM 8-methoxypsoralen (8-MOP; an inhibitor of CYP enzyme). Collectively, these findings suggest that CYP2A13 plays an important role in low-concentration AFB1-induced DNA damage, possibly linking environmental airborne AFB1 to genetic injury in human respiratory system. - Highlights: • CYP2A13 plays a critical role in low concentration of AFB1-induced DNA damage. • B-2A13 cells were more sensitive to AFB1 than B-1A2 cells and B-2A6 cells. • AFB1 dose- and time-dependently induced DNA damage in B-2A13 cells • AFB1-induced DNA adducts and damage can be inhibited by

HIV-1 Tat protein induces DNA damage in human peripheral blood B-lymphocytes via mitochondrial ROS production.

PubMed

El-Amine, Rawan; Germini, Diego; Zakharova, Vlada V; Tsfasman, Tatyana; Sheval, Eugene V; Louzada, Ruy A N; Dupuy, Corinne; Bilhou-Nabera, Chrystèle; Hamade, Aline; Najjar, Fadia; Oksenhendler, Eric; Lipinski, Marс; Chernyak, Boris V; Vassetzky, Yegor S

2018-05-01

Human immunodeficiency virus (HIV) infection is associated with B-cell malignancies in patients though HIV-1 is not able to infect B-cells. The rate of B-cell lymphomas in HIV-infected individuals remains high even under the combined antiretroviral therapy (cART) that reconstitutes the immune function. Thus, the contribution of HIV-1 to B-cell oncogenesis remains enigmatic. HIV-1 induces oxidative stress and DNA damage in infected cells via multiple mechanisms, including viral Tat protein. We have detected elevated levels of reactive oxygen species (ROS) and DNA damage in B-cells of HIV-infected individuals. As Tat is present in blood of infected individuals and is able to transduce cells, we hypothesized that it could induce oxidative DNA damage in B-cells promoting genetic instability and malignant transformation. Indeed, incubation of B-cells isolated from healthy donors with purified Tat protein led to oxidative stress, a decrease in the glutathione (GSH) levels, DNA damage and appearance of chromosomal aberrations. The effects of Tat relied on its transcriptional activity and were mediated by NF-κB activation. Tat stimulated oxidative stress in B-cells mostly via mitochondrial ROS production which depended on the reverse electron flow in Complex I of respiratory chain. We propose that Tat-induced oxidative stress, DNA damage and chromosomal aberrations are novel oncogenic factors favoring B-cell lymphomas in HIV-1 infected individuals. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Human Parvovirus B19 Utilizes Cellular DNA Replication Machinery for Viral DNA Replication.

PubMed

Zou, Wei; Wang, Zekun; Xiong, Min; Chen, Aaron Yun; Xu, Peng; Ganaie, Safder S; Badawi, Yomna; Kleiboeker, Steve; Nishimune, Hiroshi; Ye, Shui Qing; Qiu, Jianming

2018-03-01

Human parvovirus B19 (B19V) infection of human erythroid progenitor cells (EPCs) induces a DNA damage response and cell cycle arrest at late S phase, which facilitates viral DNA replication. However, it is not clear exactly which cellular factors are employed by this single-stranded DNA virus. Here, we used microarrays to systematically analyze the dynamic transcriptome of EPCs infected with B19V. We found that DNA metabolism, DNA replication, DNA repair, DNA damage response, cell cycle, and cell cycle arrest pathways were significantly regulated after B19V infection. Confocal microscopy analyses revealed that most cellular DNA replication proteins were recruited to the centers of viral DNA replication, but not the DNA repair DNA polymerases. Our results suggest that DNA replication polymerase δ and polymerase α are responsible for B19V DNA replication by knocking down its expression in EPCs. We further showed that although RPA32 is essential for B19V DNA replication and the phosphorylated forms of RPA32 colocalized with the replicating viral genomes, RPA32 phosphorylation was not necessary for B19V DNA replication. Thus, this report provides evidence that B19V uses the cellular DNA replication machinery for viral DNA replication. IMPORTANCE Human parvovirus B19 (B19V) infection can cause transient aplastic crisis, persistent viremia, and pure red cell aplasia. In fetuses, B19V infection can result in nonimmune hydrops fetalis and fetal death. These clinical manifestations of B19V infection are a direct outcome of the death of human erythroid progenitors that host B19V replication. B19V infection induces a DNA damage response that is important for cell cycle arrest at late S phase. Here, we analyzed dynamic changes in cellular gene expression and found that DNA metabolic processes are tightly regulated during B19V infection. Although genes involved in cellular DNA replication were downregulated overall, the cellular DNA replication machinery was tightly

Ultraviolet-B-induced mechanical hyperalgesia: A role for peripheral sensitisation.

PubMed

Bishop, Thomas; Marchand, Fabien; Young, Antony R; Lewin, Gary R; McMahon, Stephen B

2010-07-01

Ultraviolet (UV) induced cutaneous inflammation is emerging as a model of pain with a novel sensory phenotype. A UVB dose of 1000mJ/cm2 produces a highly significant thermal and mechanical hypersensitivity. Here we examined the properties and mechanisms of such hyperalgesia in rats. Significantly, the mechanical hyperalgesia (with approximately 60% change in withdrawal thresholds) was restricted to the lesion site with no changes in mechanical threshold in adjacent non-irradiated skin (i.e. no secondary hypersensitivity), suggesting a peripheral mechanism. Consistent with this, we found that primary mechanical hypersensitivity showed no significant changes after intrathecal treatment with 10microg of the NMDA-receptor antagonist MK-801. Using an in vitro skin-nerve preparation, in the presence and absence of UVB-inflammation, suprathreshold responses to skin displacement stimuli of 6-768microm of 103 peripheral nociceptors were recorded. At the peak of UVB-induced hyperalgesia we observed that mechanical response properties of Adelta-nociceptors recorded from UVB-inflamed skin (n=19) were significantly diminished, by approximately 50%, compared to those recorded from naïve skin (n=13). The mechanical response properties of heat-sensitive C-nociceptors were unchanged while their heat responses were significantly increased, by approximately 75%, in UVB-inflamed (n=26) compared to naïve skin (n=12). Heat-insensitive C-nociceptors, however, demonstrated significantly enhanced (by approximately 60%) response properties to mechanical stimulation in UVB-inflamed (n=21) compared to naïve skin (n=12). Notably alteration in mechanical responses of Adelta- and heat-insensitive C-nociceptors were particular to stronger stimuli. Spontaneous activity was not induced by this dose of UVB. We conclude that UVB-induced mechanical hyperalgesia may be explained by a net shift in peripheral nociceptor response properties. Copyright 2010 International Association for the Study of

Dose-Rate Effects in Breaking DNA Strands by Short Pulses of Extreme Ultraviolet Radiation.

PubMed

Vyšín, Luděk; Burian, Tomáš; Ukraintsev, Egor; Davídková, Marie; Grisham, Michael E; Heinbuch, Scott; Rocca, Jorge J; Juha, Libor

2018-05-01

In this study, we examined dose-rate effects on strand break formation in plasmid DNA induced by pulsed extreme ultraviolet (XUV) radiation. Dose delivered to the target molecule was controlled by attenuating the incident photon flux using aluminum filters as well as by changing the DNA/buffer-salt ratio in the irradiated sample. Irradiated samples were examined using agarose gel electrophoresis. Yields of single- and double-strand breaks (SSBs and DSBs) were determined as a function of the incident photon fluence. In addition, electrophoresis also revealed DNA cross-linking. Damaged DNA was inspected by means of atomic force microscopy (AFM). Both SSB and DSB yields decreased with dose rate increase. Quantum yields of SSBs at the highest photon fluence were comparable to yields of DSBs found after synchrotron irradiation. The average SSB/DSB ratio decreased only slightly at elevated dose rates. In conclusion, complex and/or clustered damages other than cross-links do not appear to be induced under the radiation conditions applied in this study.

Tualang honey protects keratinocytes from ultraviolet radiation-induced inflammation and DNA damage.

PubMed

Ahmad, Israr; Jimenez, Hugo; Yaacob, Nik Soriani; Yusuf, Nabiha

2012-01-01

Malaysian tualang honey possesses strong antioxidant and anti-inflammatory properties. Here, we evaluated the effect of tualang honey on early biomarkers of photocarcinogenesis employing PAM212 mouse keratinocyte cell line. Keratinocytes were treated with tualang honey (1.0%, v/v) before a single UVB (150 mJ cm(-2) ) irradiation. We found that the treatment of tualang honey inhibited UVB-induced DNA damage, and enhanced repair of UVB-mediated formation of cyclobutane pyrimidine dimers and 8-oxo-7,8-dihydro-2'-deoxyguanosine. Treatment of tualang honey inhibited UVB-induced nuclear translocation of NF-κB and degradation of IκBα in murine keratinocyte cell line. The treatment of tualang honey also inhibited UVB-induced inflammatory cytokines and inducible nitric oxide synthase protein expression. Furthermore, the treatment of tualang honey inhibited UVB-induced COX-2 expression and PGE2 production. Taken together, we provide evidence that the treatment of tualang honey to keratinocytes affords substantial protection from the adverse effects of UVB radiation via modulation in early biomarkers of photocarcinogenesis and provide suggestion for its photochemopreventive potential. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

UVA photoactivation of DNA containing halogenated thiopyrimidines induces cytotoxic DNA lesions

PubMed Central

Brem, Reto; Zhang, Xiaohui; Xu, Yao-Zhong; Karran, Peter

2015-01-01

Photochemotherapy, the combination of a photosensitiser and ultraviolet (UV) or visible light, is an effective treatment for skin conditions including cancer. The high mutagenicity and non-selectivity of photochemotherapy regimes warrants the development of alternative approaches. We demonstrate that the thiopyrimidine nucleosides 5-bromo-4-thiodeoxyuridine (SBrdU) and 5-iodo-4-thiodeoxyuridine (SIdU) are incorporated into the DNA of cultured human and mouse cells where they synergistically sensitise killing by low doses of UVA radiation. The DNA halothiopyrimidine/UVA combinations induce DNA interstrand crosslinks, DNA-protein crosslinks, DNA strand breaks, nucleobase damage and lesions that resemble UV-induced pyrimidine(6-4)pyrimidone photoproducts. These are potentially lethal DNA lesions and cells defective in their repair are hypersensitive to killing by SBrdU/UVA and SIdU/UVA. DNA SIdU and SBrdU generate lethal DNA photodamage by partially distinct mechanisms that reflect the different photolabilities of their C–I and C–Br bonds. Although singlet oxygen is involved in photolesion formation, DNA SBrdU and SIdU photoactivation does not detectably increase DNA 8-oxoguanine levels. The absence of significant collateral damage to normal guanine suggests that UVA activation of DNA SIdU or SBrdU might offer a strategy to target hyperproliferative skin conditions that avoids the extensive formation of a known mutagenic DNA lesion. PMID:25747491

Elevated Adenosine Induces Placental DNA Hypomethylation Independent of A2B Receptor Signaling in Preeclampsia.

PubMed

Huang, Aji; Wu, Hongyu; Iriyama, Takayuki; Zhang, Yujin; Sun, Kaiqi; Song, Anren; Liu, Hong; Peng, Zhangzhe; Tang, Lili; Lee, Minjung; Huang, Yun; Ni, Xin; Kellems, Rodney E; Xia, Yang

2017-07-01

Preeclampsia is a prevalent pregnancy hypertensive disease with both maternal and fetal morbidity and mortality. Emerging evidence indicates that global placental DNA hypomethylation is observed in patients with preeclampsia and is linked to altered gene expression and disease development. However, the molecular basis underlying placental epigenetic changes in preeclampsia remains unclear. Using 2 independent experimental models of preeclampsia, adenosine deaminase-deficient mice and a pathogenic autoantibody-induced mouse model of preeclampsia, we demonstrate that elevated placental adenosine not only induces hallmark features of preeclampsia but also causes placental DNA hypomethylation. The use of genetic approaches to express an adenosine deaminase minigene specifically in placentas, or adenosine deaminase enzyme replacement therapy, restored placental adenosine to normal levels, attenuated preeclampsia features, and abolished placental DNA hypomethylation in adenosine deaminase-deficient mice. Genetic deletion of CD73 (an ectonucleotidase that converts AMP to adenosine) prevented the elevation of placental adenosine in the autoantibody-induced preeclampsia mouse model and ameliorated preeclampsia features and placental DNA hypomethylation. Immunohistochemical studies revealed that elevated placental adenosine-mediated DNA hypomethylation predominantly occurs in spongiotrophoblasts and labyrinthine trophoblasts and that this effect is independent of A2B adenosine receptor activation in both preeclampsia models. Extending our mouse findings to humans, we used cultured human trophoblasts to demonstrate that adenosine functions intracellularly and induces DNA hypomethylation without A2B adenosine receptor activation. Altogether, both mouse and human studies reveal novel mechanisms underlying placental DNA hypomethylation and potential therapeutic approaches for preeclampsia. © 2017 American Heart Association, Inc.

Developmental and Wound-, Cold-, Desiccation-, Ultraviolet-B-Stress-Induced Modulations in the Expression of the Petunia Zinc Finger Transcription Factor Gene ZPT2-21

PubMed Central

van der Krol, Alexander R.; van Poecke, Remco M.P.; Vorst, Oscar F.J.; Voogt, Charlotte; van Leeuwen, Wessel; Borst-Vrensen, Tanja W.M.; Takatsuji, Hiroshi; van der Plas, Linus H.W.

1999-01-01

The ZPT2-2 gene belongs to the EPF gene family in petunia (Petunia hybrida), which encodes proteins with TFIIIA-type zinc-finger DNA-binding motifs. To elucidate a possible function for ZPT2-2, we analyzed its pattern of expression in relation to different developmental and physiological stress signals. The activity of the ZPT2-2 promoter was analyzed using a firefly luciferase (LUC) reporter gene, allowing for continuous measurements of transgene activity in planta. We show that ZPT2-2::LUC is active in all plant tissues, but is strongly modulated in cotyledons upon germination, in leaves in response to desiccation, cold treatment, wounding, or ultraviolet-B light, and in petal tissue in response to pollination of the stigma. Analysis of mRNA levels indicated that the modulations in ZPT2-2::LUC expression reflect modulations in endogenous ZPT2-2 gene expression. The change in ZPT2-2::LUC activity by cold treatment, wounding, desiccation, and ultraviolet-B light suggest that the phytohormones ethylene and jasmonic acid are involved in regulating the expression of ZPT2-2. Although up-regulation of expression of ZPT2-2 can be blocked by inhibitors of ethylene perception, expression in plants is not induced by exogenously applied ethylene. The application of jasmonic acid does result in an up-regulation of gene activity and, thus, ZPT2-2 may play a role in the realization of the jasmonic acid hormonal responses in petunia. PMID:10594102

Resveratrol enhances ultraviolet B-induced cell death through nuclear factor-{kappa}B pathway in human epidermoid carcinoma A431 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roy, Preeti; Kalra, Neetu; Nigam, Nidhi

Resveratrol has been reported to suppress cancer progression in several in vivo and in vitro models, whereas ultraviolet B (UVB), a major risk for skin cancer, is known to induce cell death in cancerous cells. Here, we investigated whether resveratrol can sensitize A431 human epidermoid carcinoma cells to UVB-induced cell death. We examined the combined effect of UVB (30 mJ/cm{sup 2}) and resveratrol (60 {mu}M) on A431 cells. Exposure of A431 carcinoma cells to UVB radiation or resveratrol can inhibit cell proliferation and induce apoptosis. However, the combination of resveratrol and UVB exposure was associated with increased proliferation inhibition ofmore » A431 cells compared with either agent alone. Furthermore, results showed that resveratrol and UVB treatment of A431 cells disrupted the nuclear factor-kappaB (NF-{kappa}B) pathway by blocking phosphorylation of serine 536 and inactivating NF-{kappa}B and subsequent degradation of I{kappa}B{alpha}, which regulates the expression of survivin. Resveratrol and UVB treatment also decreased the phosphorylation of tyrosine 701 of the important transcription factor signal transducer activator of transcription (STAT1), which in turn inhibited translocation of phospho-STAT1 to the nucleus. Moreover, resveratrol/UVB also inhibited the metastatic protein LIMK1, which reduced the motility of A431 cells. In conclusion, our study demonstrates that the combination of resveratrol and UVB act synergistically against skin cancer cells. Thus, resveratrol is a potential chemotherapeutic agent against skin carcinogenesis.« less

Ganglioside GT1b protects human spermatozoa from hydrogen peroxide-induced DNA and membrane damage.

PubMed

Gavella, Mirjana; Garaj-Vrhovac, Verica; Lipovac, Vaskresenija; Antica, Mariastefania; Gajski, Goran; Car, Nikica

2010-06-01

We have reported previously that various gangliosides, the sialic acid containing glycosphingolipids, provide protection against sperm injury caused by reactive oxygen species (ROS). In this study, we investigated the effect of treatment of human spermatozoa with ganglioside GT1b on hydrogen peroxide (H(2)O(2))-induced DNA fragmentation and plasma membrane damage. Single-cell gel electrophoresis (Comet assay) used in the assessment of sperm DNA integrity showed that in vitro supplemented GT1b (100 microm) significantly reduced DNA damage induced by H(2)O(2) (200 microm) (p < 0.05). Measurements of Annexin V binding in combination with the propidium iodide vital dye labelling demonstrated that the spermatozoa pre-treated with GT1b exhibited a significant increase (p < 0.05) in the percentage of live cells with intact membrane and decreased phosphatidylserine translocation after exposure to H(2)O(2). Flow cytometry using the intracellular ROS-sensitive fluorescence dichlorodihydrofluorescein diacetate dye employed to investigate the transport of the extracellularly supplied H(2)O(2) into the cell interior revealed that ganglioside GT1b completely inhibited the passage of H(2)O(2) through the sperm membrane. These results suggest that ganglioside GT1b may protect human spermatozoa from H(2)O(2)-induced damage by rendering sperm membrane more hydrophobic, thus inhibiting the diffusion of H(2)O(2) across the membrane.

Urea transporter UT-B deletion induces DNA damage and apoptosis in mouse bladder urothelium.

PubMed

Dong, Zixun; Ran, Jianhua; Zhou, Hong; Chen, Jihui; Lei, Tianluo; Wang, Weiling; Sun, Yi; Lin, Guiting; Bankir, Lise; Yang, Baoxue

2013-01-01

Previous studies found that urea transporter UT-B is abundantly expressed in bladder urothelium. However, the dynamic role of UT-B in bladder urothelial cells remains unclear. The objective of this study is to evaluate the physiological roles of UT-B in bladder urothelium using UT-B knockout mouse model and T24 cell line. Urea and NO measurement, mRNA expression micro-array analysis, light and transmission electron microscopy, apoptosis assays, DNA damage and repair determination, and intracellular signaling examination were performed in UT-B null bladders vs wild-type bladders and in vitro T24 epithelial cells. UT-B was highly expressed in mouse bladder urothelium. The genes, Dcaf11, MCM2-4, Uch-L1, Bnip3 and 45 S pre rRNA, related to DNA damage and apoptosis were significantly regulated in UT-B null urothelium. DNA damage and apoptosis highly occurred in UT-B null urothelium. Urea and NO levels were significantly higher in UT-B null urothelium than that in wild-type, which may affect L-arginine metabolism and the intracellular signals related to DNA damage and apoptosis. These findings were consistent with the in vitro study in T24 cells that, after urea loading, exhibited cell cycle delay and apoptosis. UT-B may play an important role in protecting bladder urothelium by balancing intracellular urea concentration. Disruption of UT-B function induces DNA damage and apoptosis in bladder, which can result in bladder disorders.

Dietary proanthocyanidins prevent ultraviolet radiation-induced non-melanoma skin cancer through enhanced repair of damaged DNA-dependent activation of immune sensitivity.

PubMed

Katiyar, Santosh K; Pal, Harish C; Prasad, Ram

2017-10-01

Numerous plant products have been used to prevent and manage a wide variety of diseases for centuries. These products are now considered as promising options for the development of more effective and less toxic alternatives to the systems of medicine developed primarily in developed countries in the modern era. Grape seed proanthocyanidins (GSPs) are of great interest due to their anti-carcinogenic effects that have been demonstrated using various tumor models including ultraviolet (UV) radiation-induced non-melanoma skin cancer. In a pre-clinical mouse model supplementation of a control diet (AIN76A) with GSPs at concentrations of 0.2% and 0.5% (w/w) significantly inhibits the growth and multiplicity of UVB radiation-induced skin tumors. In this review, we summarize the evidence that this inhibition of UVB-induced skin tumor development by dietary GSPs is mediated by a multiplicity of coordinated effects including: (i) Promotion of the repair of damaged DNA by nuclear excision repair mechanisms, and (ii) DNA repair-dependent stimulation of the immune system following the functional activation of dendritic cells and effector T cells. Dietary GSPs hold promise for the development of an effective alternative strategy for the prevention of excessive solar UVB radiation exposure-induced skin diseases including the risk of non-melanoma skin cancer in humans. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultraviolet Radiation-Induced Skin Aging: The Role of DNA Damage and Oxidative Stress in Epidermal Stem Cell Damage Mediated Skin Aging

PubMed Central

Panich, Uraiwan; Sittithumcharee, Gunya; Rathviboon, Natwarath

2016-01-01

Skin is the largest human organ. Skin continually reconstructs itself to ensure its viability, integrity, and ability to provide protection for the body. Some areas of skin are continuously exposed to a variety of environmental stressors that can inflict direct and indirect damage to skin cell DNA. Skin homeostasis is maintained by mesenchymal stem cells in inner layer dermis and epidermal stem cells (ESCs) in the outer layer epidermis. Reduction of skin stem cell number and function has been linked to impaired skin homeostasis (e.g., skin premature aging and skin cancers). Skin stem cells, with self-renewal capability and multipotency, are frequently affected by environment. Ultraviolet radiation (UVR), a major cause of stem cell DNA damage, can contribute to depletion of stem cells (ESCs and mesenchymal stem cells) and damage of stem cell niche, eventually leading to photoinduced skin aging. In this review, we discuss the role of UV-induced DNA damage and oxidative stress in the skin stem cell aging in order to gain insights into the pathogenesis and develop a way to reduce photoaging of skin cells. PMID:27148370

Antioxidant characterization and sensory evaluation during storage of ultraviolet-B light exposed baby carrots (abstract)

USDA-ARS?s Scientific Manuscript database

Baby carrot processing induces wounding stress activation of phenylalanine ammonia-lyase (PAL), enhancing its nutrient content by increasing synthesis of secondary metabolites. Ultraviolet-B (UV-B) exposure further promotes the formation of soluble phenolic compounds, significantly increasing antiox...

Urea Transporter UT-B Deletion Induces DNA Damage and Apoptosis in Mouse Bladder Urothelium

PubMed Central

Zhou, Hong; Chen, Jihui; Lei, Tianluo; Wang, Weiling; Sun, Yi; Lin, Guiting; Bankir, Lise; Yang, Baoxue

2013-01-01

Background Previous studies found that urea transporter UT-B is abundantly expressed in bladder urothelium. However, the dynamic role of UT-B in bladder urothelial cells remains unclear. The objective of this study is to evaluate the physiological roles of UT-B in bladder urothelium using UT-B knockout mouse model and T24 cell line. Methodology/Principal Findings Urea and NO measurement, mRNA expression micro-array analysis, light and transmission electron microscopy, apoptosis assays, DNA damage and repair determination, and intracellular signaling examination were performed in UT-B null bladders vs wild-type bladders and in vitro T24 epithelial cells. UT-B was highly expressed in mouse bladder urothelium. The genes, Dcaf11, MCM2-4, Uch-L1, Bnip3 and 45 S pre rRNA, related to DNA damage and apoptosis were significantly regulated in UT-B null urothelium. DNA damage and apoptosis highly occurred in UT-B null urothelium. Urea and NO levels were significantly higher in UT-B null urothelium than that in wild-type, which may affect L-arginine metabolism and the intracellular signals related to DNA damage and apoptosis. These findings were consistent with the in vitro study in T24 cells that, after urea loading, exhibited cell cycle delay and apoptosis. Conclusions/Significance UT-B may play an important role in protecting bladder urothelium by balancing intracellular urea concentration. Disruption of UT-B function induces DNA damage and apoptosis in bladder, which can result in bladder disorders. PMID:24204711

Nitric oxide alleviates oxidative damage induced by enhanced ultraviolet-B radiation in cyanobacterium.

PubMed

Xue, Lingui; Li, Shiweng; Sheng, Hongmei; Feng, Huyuan; Xu, Shijian; An, Lizhe

2007-10-01

To study the role of nitric oxide (NO) on enhanced ultraviolet-B (UV-B) radiation (280-320 nm)-induced damage of Cyanobacterium, the growth, pigment content, and antioxidative activity of Spirulina platensis-794 cells were investigated under enhanced UV-B radiation and under different chemical treatments with or without UV-B radiation for 6 h. The changes in chlorophyll-a, malondialdehyde content, and biomass confirmed that 0.5 mM: sodium nitroprusside (SNP), a donor of nitric oxide (NO), could markedly alleviate the damage caused by enhanced UV-B. Specifically, the biomass and the chlorophyll-a content in S. platensis-794 cells decreased 40% and 42%, respectively under enhanced UV-B stress alone, but they only decreased 10% and 18% in the cells treated with UV-B irradiation and 0.5 mM: SNP. Further experiments suggested that NO treatment significantly increased the activities of superoxide dismutase (SOD) and catalase (CAT), and decreased the accumulation of O (2)(-) in enhanced UV-B-irradiated cells. SOD and CAT activity increased 0.95- and 6.73-fold, respectively. The accumulation of reduced glutathione (GSH) increased during treatment with 0.5 mM: SNP in normal S. platensis cells, but SNP treatment could inhibit the increase of GSH in enhanced UV-B-stressed S. platensis cells. Thus, these results suggest that NO can strongly alleviate oxidative damage caused by UV-B stress by increasing the activities of SOD, peroxidase, CAT, and the accumulation of GSH, and by eliminating O (2)(-) in S. platensis-794 cells. In addition, the difference of NO origin between plants and cyanobacteria are discussed.

The effects of quercetin-loaded PLGA-TPGS nanoparticles on ultraviolet B-induced skin damages in vivo.

PubMed

Zhu, Xianbing; Zeng, Xiaowei; Zhang, Xudong; Cao, Wei; Wang, Yilin; Chen, Houjie; Wang, Teng; Tsai, Hsiang-I; Zhang, Ran; Chang, Danfeng; He, Shuai; Mei, Lin; Shi, Xiaojun

2016-04-01

Ultraviolet (UV) radiation has deleterious effects on living organisms, and functions as a tumor initiator and promoter. Multiple natural compounds, like quercetin, have been shown the protective effects on UV-induced damage. However, quercetin is extremely hydrophobic and limited by its poor percutaneous permeation and skin deposition. Here, we show that quercetin-loaded PLGA-TPGS nanoparticles could overcome low hydrophilicity of quercetin and improve its anti-UVB effect. Quercetin-loaded NPs can significantly block UVB irradiation induced COX-2 up-expression and NF-kB activation in Hacat cell line. Moreover, PLGA-TPGS NPs could efficiently get through epidermis and reach dermis. Treatment of mice with quercetin-loaded NPs also attenuates UVB irradiation-associated macroscopic and histopathological changes in mice skin. These results demonstrated that copolymer PLGA-TPGS could be used as drug nanocarriers against skin damage and disease. The findings provide an external use of PLGA-TPGS nanocarriers for application in the treatment of skin diseases. Skin is the largest organ in the body and is subjected to ultraviolet (UV) radiation damage daily from the sun. Excessive exposure has been linked to the development of skin cancer. Hence, topically applied agents can play a major role in skin protection. In this article, the authors developed quercetin-loaded PLGA-TPGS nanoparticles and showed their anti-UVB effect. Copyright © 2015 Elsevier Inc. All rights reserved.

Ultraviolet-B phototoxicity and hypothetical photomelanomagenesis: intraocular and crystalline lens photoprotection.

PubMed

Mainster, Martin A; Turner, Patricia L

2010-04-01

Ultraviolet-B (UV-B) radiation can cause phototoxic macular injuries in young people who have been sunbathing but not sungazing and in welders. Welders have a reportedly increased risk of uveal melanoma. We analyze phakic and pseudophakic risks for solar and welding arc UV-B exposure. Optical radiation measurement, analysis, and perspective. Spectral transmittances were measured for UV-transmitting, UV-blocking, and blue-blocking intraocular lenses (IOLs). The photoprotective performances of crystalline and intraocular lenses were analyzed using relevant epidemiologic and laboratory data and action spectra for acute retinal phototoxicity and melanoma photocarcinogenesis. Crystalline lens UV-B retinal protection is deficient in children and young adults, increasing their potential susceptibility to acute retinal phototoxicity and hypothetical photomelanomagenesis. UV-B radiation has sufficient energy/photon to induce primary melanomagenic DNA lesions, unlike blue light or UV-A radiation. UV-blocking and blue-blocking IOLs have negligible UV-B transmittance. UV-transmitting IOL transmittance of UV-B radiation is equivalent to that of a 15-year-old crystalline lens. If optical radiation exposure is responsible for welders' increased risk of uveal melanoma, then UV-B radiation is the most probable causative agent and spectacle wear is a potential confounding factor in epidemiologic studies of ocular melanoma. Welders under 30 years of age are at greater risk for welding maculopathy than older welders. Children, adults under 30 years of age, and pseudophakic individuals with UV-transmitting IOLs should wear sunglasses in bright environments because of the UV-B window in their crystalline lenses or IOLs. Copyright 2010 Elsevier Inc. All rights reserved.

Arctigenin protects against ultraviolet-A-induced damage to stemness through inhibition of the NF-κB/MAPK pathway.

PubMed

Park, See-Hyoung; Cho, Jae Youl; Oh, Sae Woong; Kang, Mingyeong; Lee, Seung Eun; Yoo, Ju Ah; Jung, Kwangseon; Lee, Jienny; Lee, Sang Yeol; Lee, Jongsung

2018-02-25

The stemness of stem cells is negatively affected by ultraviolet A (UVA) irradiation. This study was performed to examine the effects of arctigenin on UVA-irradiation-induced damage to the stemness of human mesenchymal stem cells (hMSCs) derived from adipose tissue. The mechanisms of action of arctigenin were also investigated. A BrdU-incorporation assay demonstrated that arctigenin attenuated the UVA-induced reduction of the cellular proliferative potential. Arctigenin also increased the UVA-induced reduction in stemness of hMSCs by upregulating stemness-related genes such as SOX2, OCT4, and NANOG. In addition, the UVA-induced reduction in the mRNA expression level of hypoxia-inducible factor (HIF)-1α was significantly recovered by arctigenin. The antagonizing effect of arctigenin on UVA irradiation was mediated by reduced PGE 2 production through the inhibition of MAPKs (p42/44 MAPK, p38 MAPK, and JNK) and NF-κB. Overall, these findings suggest that arctigenin can ameliorate the reduced stemness of hMSCs induced by UVA irradiation. The effects of arctigenin are mediated by PGE 2 -cAMP signaling-dependent upregulation of HIF-1α. Therefore, arctigenin could be used as an antagonist to attenuate the effects of UVA irradiation. Copyright © 2018 Elsevier B.V. All rights reserved.

Heme oxygenase up-regulation under ultraviolet-B radiation is not epigenetically restricted and involves specific stress-related transcriptions factors.

PubMed

Santa-Cruz, Diego; Pacienza, Natalia; Zilli, Carla; Pagano, Eduardo; Balestrasse, Karina; Yannarelli, Gustavo

2017-08-01

Heme oxygenase-1 (HO-1) plays a protective role against oxidative stress in plants. The mechanisms regulating its expression, however, remain unclear. Here we studied the methylation state of a GC rich HO-1 promoter region and the expression of several stress-related transcription factors (TFs) in soybean plants subjected to ultraviolet-B (UV-B) radiation. Genomic DNA and total RNA were isolated from leaves of plants irradiated with 7.5 and 15kJm-2 UV-B. A 304bp HO-1 promoter region was amplified by PCR from sodium bisulfite-treated DNA, cloned into pGEMT plasmid vector and evaluated by DNA sequencing. Bisulfite sequencing analysis showed similar HO-1 promoter methylation levels in control and UV-B-treated plants (C: 3.4±1.3%; 7.5: 2.6±0.5%; 15: 3.1±1.1%). Interestingly, HO-1 promoter was strongly unmethylated in control plants. Quantitative RT-PCR analysis of TFs showed that GmMYB177, GmMYBJ6, GmWRKY21, GmNAC11, GmNAC20 and GmGT2A but not GmWRK13 and GmDREB were induced by UV-B radiation. The expression of several TFs was also enhanced by hemin, a potent and specific HO inducer, inferring that they may mediate HO-1 up-regulation. These results suggest that soybean HO-1 gene expression is not epigenetically regulated. Moreover, the low level of HO-1 promoter methylation suggests that this antioxidant enzyme can rapidly respond to environmental stress. Finally, this study has identified some stress-related TFs involved in HO-1 up-regulation under UV-B radiation. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Effects of a turmeric extract (Curcuma longa) on chronic ultraviolet B irradiation-induced skin damage in melanin-possessing hairless mice.

PubMed

Sumiyoshi, Maho; Kimura, Yoshiyuki

2009-12-01

Turmeric (the rhizomes of Curcuma longa L., Zingiberacease) is widely used as a dietary pigment and spice, and has been traditionally used for the treatment of inflammation, skin wounds and hepatic disorders in Ayurvedic, Unani and Chinese medicine. Although the topical application or oral administration of turmeric is used to improve skin trouble, there is no evidence to support this effect. The aim of this study was to clarify whether turmeric prevents chronic ultraviolet B (UVB)-irradiated skin damage. We examined the effects of a turmeric extract on skin damage including changes in skin thickness and elasticity, pigmentation and wrinkling caused by long-term, low-dose ultraviolet B irradiation in melanin-possessing hairless mice. The extract (at 300 or 1000 mg/kg, twice daily) prevented an increase in skin thickness and a reduction in skin elasticity induced by chronic UVB exposure. It also prevented the formation of wrinkles and melanin (at 1000 mg/kg, twice daily) as well as increases in the diameter and length of skin blood vessels and in the expression of matrix metalloproteinase-2 (MMP-2). Prevention of UVB-induced skin aging by turmeric may be due to the inhibition of increases in MMP-2 expression caused by chronic irradiation.

Exposure of DNA bases induced by the interaction of DNA and calf thymus DNA helix-destabilizing protein.

PubMed Central

Kohwi-Shigematsu, T; Enomoto, T; Yamada, M A; Nakanishi, M; Tsuboi, M

1978-01-01

The reaction of chloroacetaldehyde with adenine bases in DNA to give a fluorescent product was used to study the availability to intermolecular reaction of positions 1 and 6 of adenine in DNA complexes with calf thymus DNA helix-destabilizing protein. No inhibition of this reaction was observed when heat-denatured DNA was complexed with the protein at a protein/DNA weight ratio of 10:1, compared to free DNA. On the contrary, the same reaction was inhibited markedly for denatured DNA in the presence of calf thymus histone HI at protein/DNA weight ratio of 2:1. Furthermore, the exchange rate for hydrogens of amino and imide groups of DNA bases in DNA strands with deuterium in the solvent was totally unaffected upon complexing of DNA with the DNA helix-destabilizing protein as examined by stopped-flow ultraviolet spectroscopy. These results indicate that the DNA helix-destabilizing protein forms a complex with single-stranded DNA, leaving DNA bases uncovered by the protein. The fluorescence intensity of DNA pretreated with chloroacetaldehyde was amplified by nearly 3-fold upon addition of the DNA helix-destabilizing protein. The possibility of "unstacking" of DNA bases induced by the protein is discussed. PMID:216994

Ultraviolet-induced movement of the human DNA repair protein, xeroderma pigmentosum type G, in the nucleus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, M.S.; Knauf, J.A.; Pendergrass, S.H.

1996-08-06

Xeroderma pigmentosum type G (XPG) is a human genetic disease exhibiting extreme sensitivity to sunlight. XPG patients are defective XPG endonuclease, which is an enzyme essential for DNA repair of the major kinds of solar ultraviolet (UV)-induced DNA damages. Here we describe a novel dynamics of this protein within the cell nucleus after UV irradiation of human cells. USing confocal microscopy, we have localized the immunofluorescent, antigenic signal of XPG protein to foci throughout the cell nucleus. Our biochemical studies also established that XPG protein forms a tight association with nuclear structure(s). In human skin fibroblast cells, the number ofmore » XPG foci decreased within 2 h after UV irradiation, whereas total nuclear XPG fluorescence intensity remained constant, suggesting redistribution of XPG from a limited number of nuclear foci to the nucleus overall. Within 8 h after UV, most XPG antigenic signal was found as foci. Using {beta}-galactosidase-XPG fusion constructs ({beta}-gal-XPG) transfected into HeLa cells, we have identified a single region of XPG that is evidently responsible both for foci formation and for the UV dynamic response. The fusion protein carrying the C terminus of XPG (amino acids 1146-1185) localized {beta}-gal specific antigenic signal to foci and to the nucleolus regions. After UV irradiation, antigenic {beta}-gal translocated reversibly from the subnuclear structures to the whole nucleus with kinetics very similar to the movements of XPG protein. These findings lead us to propose a model in which distribution of XPG protein may regulate the rate of DNA repair within transcriptionally active and inactive compartments of the cell nucleus. 50 refs., 5 figs., 1 tab.« less

Protective effect of rare earth against oxidative stress under ultraviolet-B radiation.

PubMed

Wang, Lihong; Huang, Xiaohua; Zhou, Qing

2009-04-01

The effects of lanthanum (III) (La(III)) in protecting soybean leaves against oxidative stress induced by ultraviolet-B (UV-B) radiation were investigated. The increase in contents of hydrogen peroxide (H(2)O(2)) and superoxide (O2*-) due to UV-B radiation suggested oxidative stress. The increase in the content of malondialdehyde (MDA) and the decrease in the index of unsaturated fatty acid (IUFA) indicated oxidative damage on cell membrane induced by UV-B radiation. La(III) partially reversed UV-B-radiation-induced damage of plant growth. The reduction in the contents of H(2)O(2), O2*-, and MDA and increase in the content of IUFA, compared with UV-B treatment, also indicated that La(III) alleviated the oxidative damage induced by UV-B radiation. The increase in the activities of superoxide dismutase and peroxidase and the contents of ascorbate, carotenoids, and flavonoids were observed in soybean leaves with La(III) + UV-B treatment, compared with UV-B treatment. Our data suggested that La(III) could protect soybean plants from UV-B-radiation-induced oxidative stress by reacting with reactive oxygen species directly or by improving the defense system of plants.

The production and repair of aflatoxin B sub 1 -induced DNA damage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leadon, S.A.

To investigate the influence of function or activity of a DNA sequence on its repair, we have studied excision repair of aflatoxin B{sub 1} (AFB{sub 1})-induced damage in the nontranscribed, heterochromatic alpha DNA of monkey cells and in the metallothionein genes of human cells. In confluent cells, AFB{sub 1} adducts are produced in similar frequencies in alpha and in the rest of the DNA, but removal from alpha DNA is severely deficient, however, removal of AFB{sub 1} adducts from alpha DNA is enhanced by small doses of UV. The repair deficiencies are not observed in actively growing cells. We havemore » also shown that there is preferential repair of AFB{sub 1} damage in active genes. AFB{sub 1} damage is efficiently repaired in the active human metallothionein (hMT) genes, but deficiently repaired in inactive hMT genes. 51 refs., 3 tabs.« less

Temporal variations in sirtuin expression under normal and ultraviolet B-induced conditions and their correlation to energy levels in normal human epidermal keratinocytes.

PubMed

Pelle, Edward; Dong, Kelly; Pernodet, Nadine

2015-01-01

Sirtuins are post-translational modifiers that affect transcriptional signaling, metabolism, and DNA repair. Although originally identified as gene silencers capable of extending cell lifespan, the involvement of sirtuins in many different areas of cell biology has now become widespread. Our approach has been to study the temporal variation and also the effect of environmental stressors, such as ultraviolet B (UVB) and ozone, on sirtuin expression in human epidermal keratinocytes. In this report, we measured the variation in expression of several sirtuins over time and also show how a low dose of UVB can affect this pattern of expression. Moreover, we correlated these changes to variations in hydrogen peroxide (H2O2) and ATP levels. Our data show significant variations in normal sirtuin expression, which may indicate a generalized response by sirtuins to cell cycle kinetics. These results also demonstrate that sirtuins as a family of molecules are sensitive to UVB-induced disruption and may suggest a new paradigm for determining environmental stress on aging and provide direction for the development of new cosmetic products.

Resistance of a lizard (the green anole, Anolis carolinensis; Polychridae) to ultraviolet radiation-induced immunosuppression

USGS Publications Warehouse

Cope, R.B.; Fabacher, D.L.; Lieske, C.; Miller, C.A.

2001-01-01

The green anole (Anolis carolinensis) is the most northerly distributed of its Neotropical genus. This lizard avoids a winter hibernation phase by the use of sun basking behaviors. Inevitably, this species is exposed to high doses of ambient solar ultraviolet radiation (UVR). Increases in terrestrial ultraviolet-B (UV-B) radiation secondary to stratospheric ozone depletion and habitat perturbation potentially place this species at risk of UVR-induced immunosuppression. Daily exposure to subinflammatory UVR (8 kJ/m2/day UV-B, 85 kJ/m2/day ultraviolet A [UV-A]), 6 days per week for 4 weeks (total cumulative doses of 192 kJ/m2 UV-B, 2.04 × 103 kJ/m2 UV-A) did not suppress the anole's acute or delayed type hypersensitivity (DTH) response to horseshoe crab hemocyanin. In comparison with the available literature UV-B doses as low as 0.1 and 15.9 kJ/m2 induced suppression of DTH responses in mice and humans, respectively. Exposure of anoles to UVR did not result in the inhibition of ex vivo splenocyte phagocytosis of fluorescein labeled Escherichia coli or ex vivo splenocyte nitric oxide production. Doses of UV-B ranging from 0.35 to 45 kJ/m2 have been reported to suppress murine splenic/peritoneal macrophage phagocytosis and nitric oxide production. These preliminary studies demonstrate the resistance of green anoles to UVR-induced immunosuppression. Methanol extracts of anole skin contained two peaks in the ultraviolet wavelength range that could be indicative of photoprotective substances. However, the resistance of green anoles to UVR is probably not completely attributable to absorption by UVR photoprotective substances in the skin but more likely results from a combination of other factors including absorption by the cutis and absorption and reflectance by various components of the dermis.

RuvAB and RecG are not essential for the recovery of DNA synthesis following UV-induced DNA damage in Escherichia coli.

PubMed Central

Donaldson, Janet R; Courcelle, Charmain T; Courcelle, Justin

2004-01-01

Ultraviolet light induces DNA lesions that block the progression of the replication machinery. Several models speculate that the resumption of replication following disruption by UV-induced DNA damage requires regression of the nascent DNA or migration of the replication machinery away from the blocking lesion to allow repair or bypass of the lesion to occur. Both RuvAB and RecG catalyze branch migration of three- and four-stranded DNA junctions in vitro and are proposed to catalyze fork regression in vivo. To examine this possibility, we characterized the recovery of DNA synthesis in ruvAB and recG mutants. We found that in the absence of either RecG or RuvAB, arrested replication forks are maintained and DNA synthesis is resumed with kinetics that are similar to those in wild-type cells. The data presented here indicate that RecG- or RuvAB-catalyzed fork regression is not essential for DNA synthesis to resume following arrest by UV-induced DNA damage in vivo. PMID:15126385

Naringin protects ultraviolet B-induced skin damage by regulating p38 MAPK signal pathway.

PubMed

Ren, Xiaolin; Shi, Yuling; Zhao, Di; Xu, Mengyu; Li, Xiaolong; Dang, Yongyan; Ye, Xiyun

2016-05-01

Naringin is a bioflavonoid and has free radical scavenging and anti-inflammatory properties. We examined the effects of naringin on skin after ultraviolet radiation B (UVB) irradiation and the signal pathways by in vitro and in vivo assay. HaCaT cells pretreated with naringin significantly inhibited UVB induced-cell apoptosis and production of intracellular reactive oxygen species (ROS). The expressions of interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8) and cyclooxygenase-2 (COX-2) in HaCaT cells pretreated with naringin were decreased compared with the only UVB group. Also, the activation of p38 induced by UVB in HaCaT cells was reversed by naringin treatments. The inhibition function of naringin on p38 activity was more obvious than JNK. In vivo, topical treatments with naringin prevented the increase of epidermal thickness, IL-6 production, cell apoptosis and the overexpression of COX-2 in BALB/c mice skin irradiated with UVB. Naringin treatment also markedly blocked the activation of p38 in response to UVB stimulation in the mouse skin. Naringin can effectively protect against UVB-induced keratinocyte apoptosis and skin damage by inhibiting ROS production, COX-2 overexpression and strong inflammation reactions. It seemed that naringin played its role against UVB-induced skin damage through inhibition of mitogen-activated protein kinase (MAPK)/p38 activation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Inactivation of Pseudomonas aeruginosa biofilm after ultraviolet light-emitting diode treatment: a comparative study between ultraviolet C and ultraviolet B

NASA Astrophysics Data System (ADS)

Argyraki, Aikaterini; Markvart, Merete; Bjørndal, Lars; Bjarnsholt, Thomas; Petersen, Paul Michael

2017-06-01

The objective of this study was to test the inactivation efficiency of two different light-based treatments, namely ultraviolet B (UVB) and ultraviolet C (UVC) irradiation, on Pseudomonas aeruginosa biofilms at different growth stages (24, 48, and 72 h grown). In our experiments, a type of AlGaN light-emitting diodes (LEDs) was used to deliver UV irradiation on the biofilms. The effectiveness of the UVB at 296 nm and UVC at 266 nm irradiations was quantified by counting colony-forming units. The survival of less mature biofilms (24 h grown) was studied as a function of UV-radiant exposure. All treatments were performed on three different biological replicates to test reproducibility. It was shown that UVB irradiation was significantly more effective than UVC irradiation in inactivating P. aeruginosa biofilms. UVC irradiation induced insignificant inactivation on mature biofilms. The fact that the UVB at 296 nm exists in daylight and has such disinfection ability on biofilms provides perspectives for the treatment of infectious diseases.

Solar Ultraviolet-B Radiation Affects Seedling Emergence, DNA Integrity, Plant Morphology, Growth Rate, and Attractiveness to Herbivore Insects in Datura ferox.

PubMed Central

Ballare, C. L.; Scopel, A. L.; Stapleton, A. E.; Yanovsky, M. J.

1996-01-01

To study functional relationships between the effects of solar ultraviolet-B radiation (UV-B) on different aspects of the physiology of a wild plant, we carried out exclusion experiments in the field with the summer annual Datura ferox L. Solar UV-B incident over Buenos Aires reduced daytime seedling emergence, inhibited stem elongation and leaf expansion, and tended to reduce biomass accumulation during early growth. However, UV-B had no effect on calculated net assimilation rate. Using a monoclonal antibody specific to the cyclobutane-pyrimidine dimer (CPD), we found that plants receiving full sunlight had more CPDs per unit of DNA than plants shielded from solar UV-B, but the positive correlation between UV-B and CPD burden tended to level off at high (near solar) UV-B levels. At our field site, Datura plants were consumed by leaf beetles (Coleoptera), and the proportion of plants attacked by insects declined with the amount of UV-B received during growth. Field experiments showed that plant exposure to solar UV-B reduced the likelihood of leaf beetle attack by one-half. Our results highlight the complexities associated with scaling plant responses to solar UV-B, because they show: (a) a lack of correspondence between UV-B effects on net assimilation rate and whole-plant growth rate, (b) nonlinear UV-B dose-response curves, and (c) UV-B effects of plant attractiveness to natural herbivores. PMID:12226382

Thread Embedding Acupuncture Inhibits Ultraviolet B Irradiation-Induced Skin Photoaging in Hairless Mice.

PubMed

Kim, Yoon-Jung; Kim, Ha-Neui; Shin, Mi-Sook; Choi, Byung-Tae

2015-01-01

Thread embedding acupuncture (TEA) is an acupuncture treatment applied to many diseases in Korean medical clinics because of its therapeutic effects by continuous stimulation to tissues. It has recently been used to enhance facial skin appearance and antiaging, but data from evidence-based medicine are limited. To investigate whether TEA therapy can inhibit skin photoaging by ultraviolet B (UVB) irradiation, we performed analyses for histology, histopathology, in situ zymography and western blot analysis in HR-1 hairless mice. TEA treatment resulted in decreased wrinkle formation and skin thickness (Epidermis; P = 0.001 versus UV) in UVB irradiated mice and also inhibited degradation of collagen fibers (P = 0.010 versus normal) by inhibiting proteolytic activity of gelatinase matrix-metalloproteinase-9 (MMP-9). Western blot data showed that activation of c-Jun N-terminal kinase (JNK) induced by UVB (P = 0.002 versus normal group) was significantly inhibited by TEA treatment (P = 0.005 versus UV) with subsequent alleviation of MMP-9 activation (P = 0.048 versus UV). These results suggest that TEA treatment can have anti-photoaging effects on UVB-induced skin damage by maintenance of collagen density through regulation of expression of MMP-9 and related JNK signaling. Therefore, TEA therapy may have potential roles as an alternative treatment for protection against skin damage from aging.

Thread Embedding Acupuncture Inhibits Ultraviolet B Irradiation-Induced Skin Photoaging in Hairless Mice

PubMed Central

Kim, Yoon-Jung; Kim, Ha-Neui; Shin, Mi-Sook; Choi, Byung-Tae

2015-01-01

Thread embedding acupuncture (TEA) is an acupuncture treatment applied to many diseases in Korean medical clinics because of its therapeutic effects by continuous stimulation to tissues. It has recently been used to enhance facial skin appearance and antiaging, but data from evidence-based medicine are limited. To investigate whether TEA therapy can inhibit skin photoaging by ultraviolet B (UVB) irradiation, we performed analyses for histology, histopathology, in situ zymography and western blot analysis in HR-1 hairless mice. TEA treatment resulted in decreased wrinkle formation and skin thickness (Epidermis; P = 0.001 versus UV) in UVB irradiated mice and also inhibited degradation of collagen fibers (P = 0.010 versus normal) by inhibiting proteolytic activity of gelatinase matrix-metalloproteinase-9 (MMP-9). Western blot data showed that activation of c-Jun N-terminal kinase (JNK) induced by UVB (P = 0.002 versus normal group) was significantly inhibited by TEA treatment (P = 0.005 versus UV) with subsequent alleviation of MMP-9 activation (P = 0.048 versus UV). These results suggest that TEA treatment can have anti-photoaging effects on UVB-induced skin damage by maintenance of collagen density through regulation of expression of MMP-9 and related JNK signaling. Therefore, TEA therapy may have potential roles as an alternative treatment for protection against skin damage from aging. PMID:26185518

Ultraviolet A within Sunlight Induces Mutations in the Epidermal Basal Layer of Engineered Human Skin

PubMed Central

Huang, Xiao Xuan; Bernerd, Françoise; Halliday, Gary Mark

2009-01-01

The ultraviolet B (UVB) waveband within sunlight is an important carcinogen; however, UVA is also likely to be involved. By ascribing mutations to being either UVB or UVA induced, we have previously shown that human skin cancers contain similar numbers of UVB- and UVA-induced mutations, and, importantly, the UVA mutations were at the base of the epidermis of the tumors. To determine whether these mutations occurred in response to UV, we exposed engineered human skin (EHS) to UVA, UVB, or a mixture that resembled sunlight, and then detected mutations by both denaturing high-performance liquid chromatography and DNA sequencing. EHS resembles human skin, modeling differential waveband penetration to the basal, dividing keratinocytes. We administered only four low doses of UV exposure. Both UVA and UVB induced p53 mutations in irradiated EHS, suggesting that sunlight doses that are achievable during normal daily activities are mutagenic. UVA- but not UVB-induced mutations predominated in the basal epidermis that contains dividing keratinocytes and are thought to give rise to skin tumors. These studies indicate that both UVA and UVB at physiological doses are mutagenic to keratinocytes in EHS. PMID:19264911

Photomorphogenic responses to ultraviolet-B light.

PubMed

Jenkins, Gareth I

2017-11-01

Exposure to ultraviolet B (UV-B) light regulates numerous aspects of plant metabolism, morphology and physiology through the differential expression of hundreds of genes. Photomorphogenic responses to UV-B are mediated by the photoreceptor UV RESISTANCE LOCUS8 (UVR8). Considerable progress has been made in understanding UVR8 action: the structural basis of photoreceptor function, how interaction with CONSTITUTIVELY PHOTOMORPHOGENIC 1 initiates signaling and how REPRESSOR OF UV-B PHOTOMORPHOGENESIS proteins negatively regulate UVR8 action. In addition, recent research shows that UVR8 mediates several responses through interaction with other signaling pathways, in particular auxin signaling. Nevertheless, many aspects of UVR8 action remain poorly understood. Most research to date has been undertaken with Arabidopsis, and it is important to explore the functions and regulation of UVR8 in diverse plant species. Furthermore, it is essential to understand how UVR8, and UV-B signaling in general, regulates processes under natural growth conditions. Ultraviolet B regulates the expression of many genes through UVR8-independent pathways, but the activity and importance of these pathways in plants growing in sunlight are poorly understood. © 2017 John Wiley & Sons Ltd.

Amplification of bovine papillomavirus DNA by N-methyl-N'-nitro-N-nitrosoguanidine, ultraviolet irradiation, or infection with herpes simplex virus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmitt, J.; Schlehofer, J.R.; Mergener, K.

1989-09-01

Treatment with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or irradiation with ultraviolet light (uv254 nm) induces amplification of integrated as well as episomal sequences of bovine papillomavirus (BPV) type 1 DNA in BPV-1-transformed mouse C127 cells (i.e., ID13 cells). This is shown by filter in situ hybridization and Southern blot analysis of cellular DNA. Similarly, infection of ID13 cells with herpes simplex virus (HSV) type 1 which has been shown to be mutagenic for host cell DNA leads to amplification of BPV DNA sequences. In contrast to this induction of DNA amplification by initiators, treatment of ID13 cells with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA)more » does not result in increased synthesis of BPV DNA nor does TPA treatment modulate the initiator-induced DNA amplification. Similar to other cell systems infection with adeno-associated virus (AAV) type 2 inhibits BPV-1 DNA amplification irrespective of the inducing agent. In contrast to initiator-induced DNA amplification, treatment with carcinogen (MNNG) or tumor promoters or combination of MNNG and promoter of C127 cells prior to transformation by BPV-1 does not lead to an increase in the number of transformed foci. The induction of amplification of papillomavirus DNA by initiating agents possibly represents one of the mechanisms by which the observed synergism between papillomavirus infection and initiators in tumorigenesis might occur.« less

Molecular and sensory mechanisms to mitigate sunlight-induced DNA damage in treefrog tadpoles.

PubMed

Schuch, André P; Lipinski, Victor M; Santos, Mauricio B; Santos, Caroline P; Jardim, Sinara S; Cechin, Sonia Z; Loreto, Elgion L S

2015-10-01

The increased incidence of solar ultraviolet B (UVB) radiation has been proposed as an environmental stressor, which may help to explain the enigmatic decline of amphibian populations worldwide. Despite growing knowledge regarding the UV-induced biological effects in several amphibian models, little is known about the efficacy of DNA repair pathways. In addition, little attention has been given to the interplay between these molecular mechanisms with other physiological strategies that avoid the damage induced by sunlight. Here, DNA lesions induced by environmental doses of solar UVB and UVA radiation were detected in genomic DNA samples of treefrog tadpoles (Hypsiboas pulchellus) and their DNA repair activity was evaluated. These data were complemented by monitoring the induction of apoptosis in blood cells and tadpole survival. Furthermore, the tadpoles' ability to perceive and escape from UV wavelengths was evaluated as an additional strategy of photoprotection. The results show that tadpoles are very sensitive to UVB light, which could be explained by the slow DNA repair rates for both cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6,4) pyrimidone photoproducts (6,4PPs). However, they were resistant to UVA, probably as a result of the activation of photolyases during UVA irradiation. Surprisingly, a sensory mechanism that triggers their escape from UVB and UVA light avoids the generation of DNA damage and helps to maintain the genomic integrity. This work demonstrates the genotoxic impact of both UVB and UVA radiation on tadpoles and emphasizes the importance of the interplay between molecular and sensory mechanisms to minimize the damage caused by sunlight. © 2015. Published by The Company of Biologists Ltd.

Dehydrated DNA in B-form: ionic liquids in rescue

PubMed Central

Ghoshdastidar, Debostuti; Senapati, Sanjib

2018-01-01

Abstract The functional B-conformation of DNA succumbs to the A-form at low water activity. Methods for room temperature DNA storage that rely upon ‘anhydrobiosis’, thus, often encounter the loss of DNA activity due to the B→A-DNA transition. Here, we show that ionic liquids, an emerging class of green solvents, can induce conformational transitions in DNA and even rescue the dehydrated DNA in the functional B-form. CD spectroscopic analyses not only reveal rapid transition of A-DNA in 78% ethanol medium to B-conformation in presence of ILs, but also the high resistance of IL-bound B-form to transit to A-DNA under dehydration. Molecular dynamics simulations show the unique ability of ILs to disrupt Na+ ion condensation and form ‘IL spine’ in DNA minor groove to drive the A→B transition. Implications of these findings range from the plausible use of ILs as novel anhydrobiotic DNA storage medium to a switch for modulating DNA conformational transitions. PMID:29669113

Antigenotoxic Effect Against Ultraviolet Radiation-induced DNA Damage of the Essential Oils from Lippia Species.

PubMed

Quintero Ruiz, Nathalia; Córdoba Campo, Yuri; Stashenko, Elena E; Fuentes, Jorge Luis

2017-07-01

The antigenotoxicity against ultraviolet radiation (UV)-induced DNA damage of essential oils (EO) from Lippia species was studied using SOS Chromotest. Based on the minimum concentration that significantly inhibits genotoxicity, the genoprotective potential of EO from highest to lowest was Lippia graveolens, thymol-RC ≈ Lippia origanoides, carvacrol-RC ≈ L. origanoides, thymol-RC > Lippia alba, citral-RC ≈ Lippia citriodora, citral-RC ≈ Lippia micromera, thymol-RC > L. alba, myrcenone-RC. EO from L. alba, carvone/limonene-RC, L. origanoides, α-phellandrene-RC and L. dulcis, trans-β-caryophyllene-RC did not reduce the UV genotoxicity at any of the doses tested. A gas chromatography with flame ionization detection analysis (GC-FID) was conducted to evaluate the solubility of the major EO constituents under our experimental conditions. GC-FID analysis showed that, at least partially, major EO constituents were water-soluble and therefore, they were related with the antigenotoxicity detected for EO. Constituents such as p-cymene, geraniol, carvacrol, thymol, citral and 1,8-cineole showed antigenotoxicity. The antioxidant activity of EO constituents was also determined using the oxygen radical antioxidant capacity (ORAC) assay. The results showed that the antigenotoxicity of the EO constituents was unconnected with their antioxidant activity. The antigenotoxicity to different constituent binary mixtures suggests that synergistic effects can occur in some of the studied EO. © 2017 The American Society of Photobiology.

Impact of ambient and supplemental ultraviolet-B stress on kidney bean plants: an insight into oxidative stress management.

PubMed

Singh, Suruchi; Sarkar, Abhijit; Agrawal, S B; Agrawal, Madhoolika

2014-11-01

In the present study, the response of kidney bean (Phaseolus vulgaris L. cv. Pusa Komal) plants was evaluated under three different levels of ultraviolet-B (UV-B), i.e., excluded UV-B (eUV-B), ambient UV-B (aUV-B; 5.8 kJ m(-2) day(-1)), and supplemental UV-B (sUV-B; 280-315 nm; ambient + 7.2 kJ m(-2) day(-1)), under near-natural conditions. eUV-B treatment clearly demonstrated that both aUV-B and sUV-B are capable of causing significant changes in the plant's growth, metabolism, economic yield, genome template stability, total protein, and antioxidative enzyme profiles. The experimental findings showed maximum plant height at eUV-B, but biomass accumulation was minimum. Significant reductions in quantum yield (Fv/Fm) were observed under both aUV-B and sUV-B, as compared to eUV-B. UV-B-absorbing flavonoids increased under higher UV-B exposures with consequent increments in phenylalanine ammonia lyase (PAL) activities. The final yield was significantly higher in plants grown under eUV-B, compared to those under aUV-B and sUV-B. Total protein profile through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and analysis of isoenzymes, like superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and glutathione reductase (GR), through native PAGE revealed major changes in the leaf proteome under aUV-B and sUV-B, depicting induction of some major stress-related proteins. The random amplified polymorphic DNA (RAPD) profile of genomic DNA also indicated a significant reduction of genome template stability under UV-B exposure. Thus, it can be inferred that more energy is diverted for inducing protection mechanisms rather than utilizing it for growth under high UV-B level.

[UV-induced DNA damage and protective effects of antioxidants on DNA damage in human lens epithelial cells studied with comet assay].

PubMed

Wu, Zhi-hong; Wang, Mian-rong; Yan, Qi-chang; Pu, Wei; Zhang, Jin-song

2006-11-01

To investigate the mechanism of UV-induced DNA damage and repair and the protective effects of antioxidants on DNA damage in human lens epithelial cells. Human lens epithelial cells were irradiated at UV-doses 0.0 (control group), 2.5, 5.0, 7.5, 10.0 mJ/cm(2) (treated group 1 - 4). The amounts of DNA single strand breaks (SSB) were measured with the alkaline comet assay (CA). The spontaneous repair of DNA SSB after exposure to UV at 10.0 mJ/cm(2) was also determined in human lens epithelial cells. Human lens epithelial cells were treated with different concentration of VitaminC (VitC), taurine, superoxide dismutase (SOD) and epigallocatechin gallate (EGCG) before and after ultraviolet radiation, the effects of antioxidants on DNA damage was examined with alkaline comet assay. The amount of DNA SSB in control group and treated groups 1 - 4 showed increased tendency, was dose-dependent to the dose of UV irradiation, the differences of DNA SSB in 5 group were significantly (P < 0.01). UV-induced DNA SSB at 10.0 mJ/cm(2) in human lens epithelial cells, the half repair time was 60 minutes. Human lens epithelial cells were treated with different concentrations of taurine, SOD and EGCG before ultraviolet radiation. The differences of DNA damage in control and various antioxidant treated groups was statistically significant (F = 6.591, 13.542, 4.626 in cells treated with taurine, SOD and EGCG, respectively, P < 0.01), the difference of VitC effect on DNA in control and treated group were not significantly (F = 1.451, P > 0.05). Human lens epithelial cells were treated with different concentration of VitC, taurine, SOD and EGCG after ultraviolet radiation. The differences of DNA damage between the control and treated group were statistically significant (F = 6.571, 4.810, 6.824, 9.182 in cells treated with VitC, taurine, SOD and EGCG, respectively, P < 0.01). The differences of protective effects on DNA damage in these four different kinds of antioxidants added before UV

Ultraviolet B radiation induces impaired lifecycle traits and modulates expression of cytochrome P450 (CYP) genes in the copepod Tigriopus japonicus.

PubMed

Puthumana, Jayesh; Lee, Min-Chul; Park, Jun Chul; Kim, Hui-Su; Hwang, Dae-Sik; Han, Jeonghoon; Lee, Jae-Seong

2017-03-01

To evaluate the effects of ultraviolet B (UV-B) radiation at the developmental, reproductive, and molecular levels in aquatic invertebrates, we measured UV-B-induced acute toxicity, impairments in developmental and reproductive traits, and UV-B interaction with the entire family of cytochrome P450 (CYP) genes in the intertidal benthic copepod Tigriopus japonicus. We found a significant, dose-dependent reduction (P<0.05) in the survival of T. japonicus that began as a developmental delay and decreased fecundity. The 48h LD10 and LD50 were 1.35 and 1.84kJ/m 2 , and the CYP inhibitor (PBO) elevated mortality, confirming the involvement of CYP genes in UV-B induced toxicity. Low-dose UV-B (1.5kJ/m 2 ) induced developmental delays, and higher doses (6-18kJ/m 2 ) caused reproductive impairments in ovigerous females. The significant up-regulation of CYP genes belonging to clans 2/3/MT/4/20 in T. japonicus exposed to UV-B (12kJ/m 2 ) confirmed molecular interaction between UV-B and CYP genes. Moreover, orphan CYPs, such as CYP20A1, provide good insight on the deorphanization of invertebrate CYPs. Overall, these results demonstrate the involvement of UV-B radiation in the expression of all the CYP genes in T. japonicus and their susceptibility to UV-B radiation. This will provide a better understanding of the mechanistic effects of UV-B in copepods through the predicted AhR-mediated up-regulation of CYP genes. Copyright © 2017 Elsevier B.V. All rights reserved.

Bacterial DNA-induced NK cell IFN-gamma production is dependent on macrophage secretion of IL-12.

PubMed

Chace, J H; Hooker, N A; Mildenstein, K L; Krieg, A M; Cowdery, J S

1997-08-01

Bacterial DNA (bDNA) activates B cells and macrophages and can augment inflammatory responses by inducing release of proinflammatory cytokines. We found that bDNA stimulation of mouse spleen cells induced NK cell IFN-gamma production that was dependent upon the presence of unmethylated CpG motifs, and oligonucleotides with internal CpG motifs could also induce splenocytes to secrete IFN-gamma. The bDNA-induced IFN-gamma response was strictly macrophages dependent. While splenocytes from SCID mice secreted IFN-gamma in response to bDNA, depletion of macrophages eliminated this response. Additionally, purified NK cells did not respond to bDNA; however, addition of macrophages restored the NK cell IFN-gamma response. Coculture of NK cells with preactivated macrophages further increased bDNA-induced NK cell IFN-gamma production. Anti-IL-12 or IL-10 inhibited bDNA-induced IFN-gamma response. Treatment of purified macrophages with bDNA resulted in IL-12 secretion accompanied by an increase in IL-12 p40 mRNA level. Although isolated NK cells did not make IFN-gamma in response to bDNA, NK cells costimulated with IL-12 gained the ability to respond to bDNA. These experiments show that bDNA induces macrophage IL-12 production which, in turn, stimulates NK cell IFN-gamma production. Macrophage-derived IL-12 renders NK cells responsive to bDNA permitting an even greater IFN-gamma response to bDNA.

Extract from Periostracum cicadae Inhibits Oxidative Stress and Inflammation Induced by Ultraviolet B Irradiation on HaCaT Keratinocytes

PubMed Central

Tsen, Jen-Horng; Yen, Hsuan; Yang, Ting-Ya

2017-01-01

Periostracum cicadae is widely used for the treatment of skin diseases such as eczema, pruritus, and itching. The current study sought to evaluate the effect of P. cicadae extract on ultraviolet B (UVB) irradiation and identify the mechanisms involved. Photodamage-protective activity of P. cicadae extracts against oxidative challenge was screened using HaCaT keratinocytes. P. cicadae extracts did not affect cell viability but decreased reactive oxygen species (ROS) production. The extract attenuates the expression of interleukin-6 (IL-6), matrix metalloproteinase-2 (MMP-2), and MMP-9 in UVB-treated HaCaT cells. Also, P. cicadae abrogated UVB-induced activation of NF-κB, p53, and activator protein-1 (AP-1). The downmodulation of IL-6 by P. cicadae was inhibited by the p38 inhibitor (SB203580) or JNK inhibitor (SP600125). Moreover, the extract attenuated the expression of NF-κB and induced thrombomodulin in keratinocytes and thereby effectively downregulated inflammatory responses in the skin. The nuclear accumulation and expression of NF-E2-related factor (Nrf2) were increased by P. cicadae treatment. Furthermore, treatment with P. cicadae remarkably ameliorated the skin's structural damage induced by irradiation. This study demonstrates that P. cicadae may protect skin cells against oxidative insult by modulating ROS concentration, IL-6, MMPs generation, antioxidant enzymes activity, and cell signaling pathways. PMID:28465707

Ethanol extract of Dalbergia odorifera protects skin keratinocytes against ultraviolet B-induced photoaging by suppressing production of reactive oxygen species.

PubMed

Ham, Sun Ah; Hwang, Jung Seok; Kang, Eun Sil; Yoo, Taesik; Lim, Hyun Ho; Lee, Won Jin; Paek, Kyung Shin; Seo, Han Geuk

2015-01-01

Dalbergia odorifera T. Chen (Leguminosae), an indigenous medicinal herb, has been widely used in northern and eastern Asia to treat diverse diseases. Here, we investigated the anti-senescent effects of ethanolic extracts of Dalbergia odorifera (EEDO) in ultraviolet (UV) B-irradiated skin cells. EEDO significantly inhibited UVB-induced senescence of human keratinocytes in a concentration-dependent manner, concomitant with inhibition of reactive oxygen species (ROS) generation. UVB-induced increases in the levels of p53 and p21, biomarkers of cellular senescence, were almost completely abolished in the presence of EEDO. Sativanone, a major constituent of EEDO, also attenuated UVB-induced senescence and ROS generation in keratinocytes, indicating that sativanone is an indexing (marker) molecule for the anti-senescence properties of EEDO. Finally, treatment of EEDO to mice exposed to UVB significantly reduced ROS levels and the number of senescent cells in the skin. Thus, EEDO confers resistance to UVB-induced cellular senescence by inhibiting ROS generation in skin cells.

Salvianolic Acid B Protects Normal Human Dermal Fibroblasts Against Ultraviolet B Irradiation-Induced Photoaging Through Mitogen-Activated Protein Kinase and Activator Protein-1 Pathways.

PubMed

Sun, Zhengwang; Park, Sang-Yong; Hwang, Eunson; Zhang, Mengyang; Jin, Fengxie; Zhang, Baochun; Yi, Tae Hoo

2015-01-01

Exposure to ultraviolet (UV) light causes increased matrix metalloproteinase (MMP) activity and decreased collagen synthesis, leading to skin photoaging. Salvianolic acid B (SAB), a polyphenol, was extracted and purified from salvia miltiorrhiza. We assessed effects of SAB on UVB-induced photoaging and investigated its molecular mechanism of action in UVB-irradiated normal human dermal fibroblasts. Our results show that SAB significantly inhibited the UVB-induced expression of metalloproteinases-1 (MMP-1) and interleukin-6 (IL-6) while promoting the production of type I procollagen and transforming growth factor β1 (TGF-β1). Moreover, treatment with SAB in the range of 1-100 μg/mL significantly inhibited UVB-induced extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK) and p38 phosphorylation, which resulted in decreasing UVB-induced phosphorylation of c-Fos and c-Jun. These results indicate that SAB downregulates UV-induced MMP-1 expression by inhibiting Mitogen-activated protein kinase (MAPK) signaling pathways and activator protein-1 (AP-1) activation. Our results suggest a potential use for SAB in skin photoprotection. © 2015 The American Society of Photobiology.

Z-ligustilide ameliorated ultraviolet B-induced oxidative stress and inflammatory cytokine production in human keratinocytes through upregulation of Nrf2/HO-1 and suppression of NF-κB pathway.

PubMed

Wu, Zhouwei; Uchi, Hiroshi; Morino-Koga, Saori; Shi, Weimin; Furue, Masutaka

2015-09-01

Ultraviolet B (UVB), a harmful environmental factor, is responsible for a variety of skin disorders including skin inflammation through reactive oxygen species (ROS) and inflammatory mediator production. Here, we investigated the effect of Z-ligustilide (Z-lig), an active ingredient isolated from the medicinal plants Cnidium officinale and Angelica acutiloba, on UVB-induced ROS generation and inflammatory mediator production in normal human epidermal keratinocytes (NHEKs) as well as its underlying mechanisms. Z-lig significantly rescued UVB-induced NHEKs damage in a dosage-dependent manner. Pretreatment of NHEKs with Z-lig inhibited UVB-induced ROS production in NHEKs. Both silencing the nuclear factor E2-related factor 2 (Nrf2) and the supplement of tin protoporphyrin IX (SnPP), a haeme oxygenase-1 (HO-1) inhibitor, cancelled the inhibitory effect of Z-lig on UVB-induced ROS upregulation in NHEKs. Moreover, pretreatment of NHEKs with Z-lig reduced UVB-induced nuclear factor kappa B (NF-κB)-dependent inflammatory mediators (IL-6, IL-8 and MCP-1) production at both mRNA and protein level. In the presence of Z-lig, UVB-induced NF-κB subunit p65 nuclear translocation was abolished, and the IκBα degradation was suppressed. Taken together, these findings suggest that Z-lig can suppress UVB-induced ROS generation through Nrf2/HO-1 upregulation and inflammation by suppressing the NF-κB pathway, suggesting that Z-lig may be beneficial in protecting skin from UVB exposure. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Feasibility of Ionization-Mediated Pathway for Ultraviolet-Induced Melanin Damage.

PubMed

Mandal, Mukunda; Das, Tamal; Grewal, Baljinder K; Ghosh, Debashree

2015-10-22

Melanin is the pigment found in human skin that is responsible for both photoprotection and photodamage. Recently there have been reports that greater photodamage of DNA occurs when cells containing melanin are irradiated with ultraviolet (UV) radiation, thus suggesting that the photoproducts of melanin cause DNA damage. Photoionization processes have also been implicated in the photodegradation of melanin. However, not much is known about the oxidation potential of melanin and its monomers. In this work we calculate the ionization energies of monomers, dimers, and few oligomers of eumelanin to estimate the threshold energy required for the ionization of eumelanin. We find that this threshold is within the UV-B region for eumelanin. We also look at the charge and spin distributions of the various ionized states of the monomers that are formed to understand which of the ionization channels might favor monomerization from a covalent dimer.

Radiative lifetimes in B I using ultraviolet and vacuum-ultraviolet laser-induced fluorescence

NASA Technical Reports Server (NTRS)

O'Brian, T. R.; Lawler, J. E.

1992-01-01

Radiative lifetimes of the eight lowest even parity levels in the doublet system of B I are measured using time-resolved laser-induced fluorescence in the UV and VUV on an atomic beam of boron. The accurate lifetimes provide a base for improved determination of absolute transition probabilities in B I. The techniques described are broadly applicable to measurement of lifetimes of levels with transitions in the visible, UV, and VUV in almost any element.

UV-B-induced DNA damage and repair in the mouse lens.

PubMed

Mesa, Rosana; Bassnett, Steven

2013-10-17

Epidemiologic studies have linked UV-B exposure to development of cortical cataracts, but the underlying molecular mechanism(s) is unresolved. Here, we used a mouse model to examine the nature and distribution of DNA photolesions produced by ocular UV-B irradiation. Anesthetized mice, eye globes, or isolated lenses were exposed to UV-B. Antibodies specific for 6-4 photoproducts (6-4 PPs) or cyclobutane pyrimidine dimers (CPDs) were used to visualize DNA adducts. Illumination of intact globes with UV-B-induced 6-4 PP and CPD formation in cells of the cornea, anterior iris, and central lens epithelium. Photolesions were not detected in retina or lens cells situated in the shadow of the iris. Photolesions in lens epithelial cells were produced with radiant exposures significantly below the minimal erythemal dose. Lens epithelial cells rapidly repaired 6-4 PPs, but CPD levels did not markedly diminish, even over extended postirradiation recovery periods in vitro or in vivo. The repair of 6-4 PPs did not depend on the proliferative activity of the epithelial cells, since the repair rate in the mitotically-active germinative zone (GZ) was indistinguishable from that of quiescent cells in the central epithelium. Even relatively modest exposures to UV-B produced 6-4 PP and CPD photolesions in lens epithelial cells. Cyclobutane pyrimidine dimer lesions were particularly prevalent and were repaired slowly if at all. Studies on sun-exposed skin have established a causal connection between photolesions and so-called UV-signature mutations. If similar mechanisms apply in the lens, it suggests that somatic mutations in lens epithelial cells may contribute to the development of cortical cataracts.

Molecular cloning and characterization of a tomato cDNA encoding a systemically wound-inducible bZIP DNA-binding protein

NASA Technical Reports Server (NTRS)

Stankovic, B.; Vian, A.; Henry-Vian, C.; Davies, E.

2000-01-01

Localized wounding of one leaf in intact tomato (Lycopersicon esculentum Mill.) plants triggers rapid systemic transcriptional responses that might be involved in defense. To better understand the mechanism(s) of intercellular signal transmission in wounded tomatoes, and to identify the array of genes systemically up-regulated by wounding, a subtractive cDNA library for wounded tomato leaves was constructed. A novel cDNA clone (designated LebZIP1) encoding a DNA-binding protein was isolated and identified. This clone appears to be encoded by a single gene, and belongs to the family of basic leucine zipper domain (bZIP) transcription factors shown to be up-regulated by cold and dark treatments. Analysis of the mRNA levels suggests that the transcript for LebZIP1 is both organ-specific and up-regulated by wounding. In wounded wild-type tomatoes, the LebZIP1 mRNA levels in distant tissue were maximally up-regulated within only 5 min following localized wounding. Exogenous abscisic acid (ABA) prevented the rapid wound-induced increase in LebZIP1 mRNA levels, while the basal levels of LebZIP1 transcripts were higher in the ABA mutants notabilis (not), sitiens (sit), and flacca (flc), and wound-induced increases were greater in the ABA-deficient mutants. Together, these results suggest that ABA acts to curtail the wound-induced synthesis of LebZIP1 mRNA.

Using natural dietary sources of antioxidants to protect against ultraviolet and visible radiation-induced DNA damage: an investigation of human green tea ingestion.

PubMed

Malhomme de la Roche, Helena; Seagrove, Susan; Mehta, Anisha; Divekar, Preshita; Campbell, Sandra; Curnow, Alison

2010-11-03

Oral ingestion of green tea is a potent dietary source of antioxidant polyphenols. These compounds are of interest as they may be able to provide additional protection to the body to help prevent the deleterious effects of ultraviolet A and visible radiation (UVA/VIS) produced indirectly via reactive oxygen species (ROS) in sunlight exposed skin. A small clinical study was conducted in ten healthy adult volunteers. Samples of whole blood were obtained from each before and 30, 60 and 90 min following ingestion of three breakfast cups of green tea (540 ml in total) prepared in a standardised manner. Peripheral leucocytes were isolated from each blood sample and exposed to increasing periods of UVA/VIS irradiation in the laboratory (0, 9, 12 or 18 min). Alkaline single cell gel electrophoresis (the comet assay) was then conducted to determine the level of DNA damage in each sample from each individual. The findings support those of our previous pilot study and indicate that drinking green tea did significantly reduce the genotoxic effects observed in peripheral blood cells 60 min following ingestion when artificially exposed to 12 min of UVA/VIS irradiation in the laboratory. It is postulated that this protection is afforded by the polyphenol compounds (known to be contained within green tea) via scavenging or quenching of the damaging ROS induced by this form of light exposure. Further investigation should consider whether this dietary-induced protection could be extended to cells of the skin. Copyright © 2010 Elsevier B.V. All rights reserved.

Kaempferol Modulates DNA Methylation and Downregulates DNMT3B in Bladder Cancer.

PubMed

Qiu, Wei; Lin, Jun; Zhu, Yichen; Zhang, Jian; Zeng, Liping; Su, Ming; Tian, Ye

2017-01-01

Genomic DNA methylation plays an important role in both the occurrence and development of bladder cancer. Kaempferol (Kae), a natural flavonoid that is present in many fruits and vegetables, exhibits potent anti-cancer effects in bladder cancer. Similar to other flavonoids, Kae possesses a flavan nucleus in its structure. This structure was reported to inhibit DNA methylation by suppressing DNA methyltransferases (DNMTs). However, whether Kae can inhibit DNA methylation remains unclear. Nude mice bearing bladder cancer were treated with Kae for 31 days. The genomic DNA was extracted from xenografts and the methylation changes was determined using an Illumina Infinium HumanMethylation 450 BeadChip Array. The ubiquitination was detected using immuno-precipitation assay. Our data indicated that Kae modulated DNA methylation in bladder cancer, inducing 103 differential DNA methylation positions (dDMPs) associated with genes (50 hyper-methylated and 53 hypo-methylated). DNA methylation is mostly relied on the levels of DNMTs. We observed that Kae specifically inhibited the protein levels of DNMT3B without altering the expression of DNMT1 or DNMT3A. However, Kae did not downregulate the transcription of DNMT3B. Interestingly, we observed that Kae induced a premature degradation of DNMT3B by inhibiting protein synthesis with cycloheximide (CHX). By blocking proteasome with MG132, we observed that Kae induced an increased ubiquitination of DNMT3B. These results suggested that Kae could induce the degradation of DNMT3B through ubiquitin-proteasome pathway. Our data indicated that Kae is a novel DNMT3B inhibitor, which may promote the degradation of DNMT3B in bladder cancer. © 2017 The Author(s)Published by S. Karger AG, Basel.

DNA Damage in Bone Marrow Cells Induced by Femtosecond and Nanosecond Ultraviolet Laser Pulses.

PubMed

Morkunas, Vaidotas; Gabryte, Egle; Vengris, Mikas; Danielius, Romualdas; Danieliene, Egle; Ruksenas, Osvaldas

2015-12-01

The purpose of this study was to investigate the possible genotoxic impact of new generation 205 nm femtosecond solid-state laser irradiation on the DNA of murine bone marrow cells in vitro, and to compare the DNA damage caused by both femtosecond and nanosecond UV laser pulses. Recent experiments of corneal stromal ablation in vitro and in vivo applying femtosecond UV pulses showed results comparable with or superior to those obtained using nanosecond UV lasers. However, the possible genotoxic effect of ultrashort laser pulses was not investigated. Mouse bone marrow cells were exposed to different doses of 205 nm femtosecond, 213 and 266 nm nanosecond lasers, and 254 nm UV lamp irradiation. The comet assay was used for the evaluation of DNA damage. All types of irradiation demonstrated intensity-dependent genotoxic impact. The DNA damage induced depended mainly upon wavelength rather than on other parameters such as pulse duration, repetition rate, or beam delivery to a target. Both 205 nm femtosecond and clinically applied 213 nm nanosecond lasers' pulses induced a comparable amount of DNA breakage in cells exposed to the same irradiation dose. To further evaluate the suitability of femtosecond UV laser sources for microsurgery, a separate investigation of the genotoxic and mutagenic effects on corneal cells in vitro and, particularly, in vivo is needed.

Non-B-DNA structures on the interferon-beta promoter?

PubMed

Robbe, K; Bonnefoy, E

1998-01-01

The high mobility group (HMG) I protein intervenes as an essential factor during the virus induced expression of the interferon-beta (IFN-beta) gene. It is a non-histone chromatine associated protein that has the dual capacity of binding to a non-B-DNA structure such as cruciform-DNA as well as to AT rich B-DNA sequences. In this work we compare the binding affinity of HMGI for a synthetic cruciform-DNA to its binding affinity for the HMGI-binding-site present in the positive regulatory domain II (PRDII) of the IFN-beta promoter. Using gel retardation experiments, we show that HMGI protein binds with at least ten times more affinity to the synthetic cruciform-DNA structure than to the PRDII B-DNA sequence. DNA hairpin sequences are present in both the human and the murine PRDII-DNAs. We discuss in this work the presence of, yet putative, non-B-DNA structures in the IFN-beta promoter.

Targeting neddylation induces DNA damage and checkpoint activation and sensitizes chronic lymphocytic leukemia B cells to alkylating agents.

PubMed

Paiva, C; Godbersen, J C; Berger, A; Brown, J R; Danilov, A V

2015-07-09

Microenvironment-mediated upregulation of the B-cell receptor (BCR) and nuclear factor-κB (NF-κB) signaling in CLL cells resident in the lymph node and bone marrow promotes apoptosis evasion and clonal expansion. We recently reported that MLN4924 (pevonedistat), an investigational agent that inhibits the NEDD8-activating enzyme (NAE), abrogates stromal-mediated NF-κB pathway activity and CLL cell survival. However, the NAE pathway also assists degradation of multiple other substrates. MLN4924 has been shown to induce DNA damage and cell cycle arrest, but the importance of this mechanism in primary neoplastic B cells has not been studied. Here we mimicked the lymph node microenvironment using CD40 ligand (CD40L)-expressing stroma and interleukin-21 (IL-21) to find that inducing proliferation of the primary CLL cells conferred enhanced sensitivity to NAE inhibition. Treatment of the CD40-stimulated CLL cells with MLN4924 resulted in deregulation of Cdt1, a DNA replication licensing factor, and cell cycle inhibitors p21 and p27. This led to DNA damage, checkpoint activation and G2 arrest. Alkylating agents bendamustine and chlorambucil enhanced MLN4924-mediated DNA damage and apoptosis. These events were more prominent in cells stimulated with IL-21 compared with CD40L alone, indicating that, following NAE inhibition, the culture conditions were able to direct CLL cell fate from an NF-κB inhibition to a Cdt1 induction program. Our data provide insight into the biological consequences of targeting NAE in CLL and serves as further rationale for studying the clinical activity of MLN4924 in CLL, particularly in combination with alkylating agents.

Targeting neddylation induces DNA damage and checkpoint activation and sensitizes chronic lymphocytic leukemia B cells to alkylating agents

PubMed Central

Paiva, C; Godbersen, J C; Berger, A; Brown, J R; Danilov, A V

2015-01-01

Microenvironment-mediated upregulation of the B-cell receptor (BCR) and nuclear factor-κB (NF-κB) signaling in CLL cells resident in the lymph node and bone marrow promotes apoptosis evasion and clonal expansion. We recently reported that MLN4924 (pevonedistat), an investigational agent that inhibits the NEDD8-activating enzyme (NAE), abrogates stromal-mediated NF-κB pathway activity and CLL cell survival. However, the NAE pathway also assists degradation of multiple other substrates. MLN4924 has been shown to induce DNA damage and cell cycle arrest, but the importance of this mechanism in primary neoplastic B cells has not been studied. Here we mimicked the lymph node microenvironment using CD40 ligand (CD40L)-expressing stroma and interleukin-21 (IL-21) to find that inducing proliferation of the primary CLL cells conferred enhanced sensitivity to NAE inhibition. Treatment of the CD40-stimulated CLL cells with MLN4924 resulted in deregulation of Cdt1, a DNA replication licensing factor, and cell cycle inhibitors p21 and p27. This led to DNA damage, checkpoint activation and G2 arrest. Alkylating agents bendamustine and chlorambucil enhanced MLN4924-mediated DNA damage and apoptosis. These events were more prominent in cells stimulated with IL-21 compared with CD40L alone, indicating that, following NAE inhibition, the culture conditions were able to direct CLL cell fate from an NF-κB inhibition to a Cdt1 induction program. Our data provide insight into the biological consequences of targeting NAE in CLL and serves as further rationale for studying the clinical activity of MLN4924 in CLL, particularly in combination with alkylating agents. PMID:26158513

Interactions of RadB, a DNA repair protein in archaea, with DNA and ATP.

PubMed

Guy, Colin P; Haldenby, Sam; Brindley, Amanda; Walsh, David A; Briggs, Geoffrey S; Warren, Martin J; Allers, Thorsten; Bolt, Edward L

2006-04-21

The RecA family of recombinases (RecA, Rad51, RadA and UvsX) catalyse strand-exchange between homologous DNA molecules by utilising conserved DNA-binding modules and a common core ATPase domain. RadB was identified in archaea as a Rad51-like protein on the basis of conserved ATPase sequences. However, RadB does not catalyse strand exchange and does not turn over ATP efficiently. RadB does bind DNA, and here we report a triplet of residues (Lys-His-Arg) that is highly conserved at the RadB C terminus, and is crucial for DNA binding. This is consistent with the motif forming a "basic patch" of highly conserved residues identified in an atomic structure of RadB from Thermococcus kodakaraensis. As the triplet motif is conserved at the C terminus of XRCC2 also, a mammalian Rad51-paralogue, we present a phylogenetic analysis that clarifies the relationship between RadB, Rad51-paralogues and recombinases. We investigate interactions between RadB and ATP using genetics and biochemistry; ATP binding by RadB is needed to promote survival of Haloferax volcanii after UV irradiation, and ATP, but not other NTPs, induces pronounced conformational change in RadB. This is the first genetic analysis of radB, and establishes its importance for maintaining genome stability in archaea. ATP-induced conformational change in RadB may explain previous reports that RadB controls Holliday junction resolution by Hjc, depending on the presence or the absence of ATP.

Interleukin-10 functions in vitro and in vivo to inhibit bacterial DNA-induced secretion of interleukin-12.

PubMed

Anitescu, M; Chace, J H; Tuetken, R; Yi, A K; Berg, D J; Krieg, A M; Cowdery, J S

1997-12-01

Bacterial DNA (bDNA) has a number of biologic properties, including the ability to induce interleukin-12 (IL-12) production by macrophages. We studied the role of the regulatory cytokine IL-10 as a potential inhibitor of bDNA-induced IL-12 production. IL-10 concentrations as low as 0.3 ng/ml profoundly inhibited bDNA-induced macrophage IL-12 production as measured by Elispot analysis of IL-12 p40-secreting cells. Additionally, we found that IL-10 inhibited bDNA-induced IL-12 secretion by the macrophage cell lines J774 and RAW 264. Preincubation of splenic adherent cells with IL-10 markedly reduced bDNA-induced transcription of IL-12 p40 mRNA. Interestingly, after 2 h of exposure, bDNA also induces transcription of IL-10 mRNA by splenic adherent cells. The importance of IL-10 in the in vivo regulation of bDNA-induced cytokine secretion was illustrated by the response of mice with disrupted IL-10 genes (IL-10 ko mice) to i.v. bDNA challenge. Compared to +/+ mice, IL-10 knockout (ko) mice exhibited increased numbers of IL-12 and interferon-gamma (IFN-gamma)-secreting cells following either single or repeated challenge with bDNA. These findings indicate that IL-10 plays a key role in regulating bDNA-induced production of inflammatory cytokines.

Topical Formulation Containing Naringenin: Efficacy against Ultraviolet B Irradiation-Induced Skin Inflammation and Oxidative Stress in Mice

PubMed Central

Martinez, Renata M.; Pinho-Ribeiro, Felipe A.; Steffen, Vinicius S.; Silva, Thais C. C.; Caviglione, Carla V.; Bottura, Carolina; Fonseca, Maria J. V.; Vicentini, Fabiana T. M. C.; Vignoli, Josiane A.; Baracat, Marcela M.; Georgetti, Sandra R.; Verri, Waldiceu A.; Casagrande, Rubia

2016-01-01

Naringenin (NGN) exhibits anti-inflammatory and antioxidant activities, but it remains undetermined its topical actions against ultraviolet B (UVB)-induced inflammation and oxidative stress in vivo. The purpose of this study was to evaluate the physicochemical and functional antioxidant stability of NGN containing formulations, and the effects of selected NGN containing formulation on UVB irradiation-induced skin inflammation and oxidative damage in hairless mice. NGN presented ferric reducing power, ability to scavenge 2,2′-azinobis (3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS) and hydroxyl radical, and inhibited iron-independent and dependent lipid peroxidation. Among the three formulations containing NGN, only the F3 kept its physicochemical and functional stability over 180 days. Topical application of F3 in mice protected from UVB-induced skin damage by inhibiting edema and cytokine production (TNF-α, IL-1β, IL-6, and IL-10). Furthermore, F3 inhibited superoxide anion and lipid hydroperoxides production and maintained ferric reducing and ABTS scavenging abilities, catalase activity, and reduced glutathione levels. In addition, F3 maintained mRNA expression of cellular antioxidants glutathione peroxidase 1, glutathione reductase and transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2), and induced mRNA expression of heme oxygenase-1. In conclusion, a formulation containing NGN may be a promising approach to protecting the skin from the deleterious effects of UVB irradiation. PMID:26741806

Photosensitized UVA-Induced Cross-Linking between Human DNA Repair and Replication Proteins and DNA Revealed by Proteomic Analysis

PubMed Central

2016-01-01

Long wavelength ultraviolet radiation (UVA, 320–400 nm) interacts with chromophores present in human cells to induce reactive oxygen species (ROS) that damage both DNA and proteins. ROS levels are amplified, and the damaging effects of UVA are exacerbated if the cells are irradiated in the presence of UVA photosensitizers such as 6-thioguanine (6-TG), a strong UVA chromophore that is extensively incorporated into the DNA of dividing cells, or the fluoroquinolone antibiotic ciprofloxacin. Both DNA-embedded 6-TG and ciprofloxacin combine synergistically with UVA to generate high levels of ROS. Importantly, the extensive protein damage induced by these photosensitizer+UVA combinations inhibits DNA repair. DNA is maintained in intimate contact with the proteins that effect its replication, transcription, and repair, and DNA–protein cross-links (DPCs) are a recognized reaction product of ROS. Cross-linking of DNA metabolizing proteins would compromise these processes by introducing physical blocks and by depleting active proteins. We describe a sensitive and statistically rigorous method to analyze DPCs in cultured human cells. Application of this proteomics-based analysis to cells treated with 6-TG+UVA and ciprofloxacin+UVA identified proteins involved in DNA repair, replication, and gene expression among those most vulnerable to cross-linking under oxidative conditions. PMID:27654267

Anti-Photoaging Effect of Jeju Putgyul (Unripe Citrus) Extracts on Human Dermal Fibroblasts and Ultraviolet B-induced Hairless Mouse Skin.

PubMed

Choi, Seung-Hyun; Choi, Sun-Il; Jung, Tae-Dong; Cho, Bong-Yeon; Lee, Jin-Ha; Kim, Seung-Hyung; Yoon, Seon-A; Ham, Young-Min; Yoon, Weon-Jong; Cho, Ju-Hyun; Lee, Ok-Hawn

2017-09-25

Ultraviolet (UV) radiation stimulates the expression of matrix metalloproteinases (MMPs) and inflammatory cytokines. These signaling pathways participate in the degradation of the extracellular matrix and induce inflammatory responses that lead to photoaging. This study evaluated the antioxidant activity and the effect on MMPs and procollagen of putgyul extract in vitro. The anti-photoaging activity of putgyul extracts was estimated in vivo using hairless mice (HR-1). The putgyul extracts reduced MMP-1 production and increased the content of procollagen type I carboxy-terminal peptide in human dermal fibroblasts. Ultravilot-B (UVB)-induced expression of inflammatory cytokines and MMPs was detected in mice, and putgyul extracts suppressed the expression. These results suggest that putgyul extract inhibits photoaging by inhibiting the expression of MMPs that degrade collagen and inhibiting cytokines that induce inflammatory responses. The mouse model also demonstrated that oral administration of putgyul extracts decreased wrinkle depth, epidermal thickness, collagen degradation, and trans-epidermal water loss, and increased β-glucosidase activity on UVB exposed skin. Putgyul extract protects against UVB-induced damage of skin and could be valuable in the prevention of photoaging.

Cerium chloride stimulated controlled conversion of B-to-Z DNA in self-assembled nanostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhanjadeo, Madhabi M.; Academy of Scientific & Innovative Research; Nayak, Ashok K.

DNA adopts different conformation not only because of novel base pairs but also while interacting with inorganic or organic compounds. Self-assembled branched DNA (bDNA) structures or DNA origami that change conformation in response to environmental cues hold great promises in sensing and actuation at the nanoscale. Recently, the B-Z transition in DNA is being explored to design various nanomechanical devices. In this communication we have demonstrated that Cerium chloride binds to the phosphate backbone of self-assembled bDNA structure and induce B-to-Z transition at physiological concentration. The mechanism of controlled conversion from right-handed to left-handed has been assayed by various dyemore » binding studies using CD and fluorescence spectroscopy. Three different bDNA structures have been identified to display B-Z transition. This approach provides a rapid and reversible means to change bDNA conformation, which can be used for dynamic and progressive control at the nanoscale. - Highlights: • Cerium-induced B-to-Z DNA transition in self-assembled nanostructures. • Lower melting temperature of Z-DNA than B-DNA confirmed by CD spectroscopy. • Binding mechanism of cerium chloride is explained using fluorescence spectroscopy. • Right-handed to left-handed DNA conformation is also noticed in modified bDNA structure.« less

Lanthanum induced B-to-Z transition in self-assembled Y-shaped branched DNA structure

PubMed Central

Nayak, Ashok K.; Mishra, Aseem; Jena, Bhabani S.; Mishra, Barada K.; Subudhi, Umakanta

2016-01-01

Controlled conversion of right-handed B-DNA to left-handed Z-DNA is one of the greatest conformational transitions in biology. Recently, the B-Z transition has been explored from nanotechnological points of view and used as the driving machinery of many nanomechanical devices. Using a combination of CD spectroscopy, fluorescence spectroscopy, and PAGE, we demonstrate that low concentration of lanthanum chloride can mediate B-to-Z transition in self-assembled Y-shaped branched DNA (bDNA) structure. The transition is sensitive to the sequence and structure of the bDNA. Thermal melting and competitive dye binding experiments suggest that La3+ ions are loaded to the major and minor grooves of DNA and stabilize the Z-conformation. Our studies also show that EDTA and EtBr play an active role in reversing the transition from Z-to-B DNA. PMID:27241949

Lanthanum induced B-to-Z transition in self-assembled Y-shaped branched DNA structure

NASA Astrophysics Data System (ADS)

Nayak, Ashok K.; Mishra, Aseem; Jena, Bhabani S.; Mishra, Barada K.; Subudhi, Umakanta

2016-05-01

Controlled conversion of right-handed B-DNA to left-handed Z-DNA is one of the greatest conformational transitions in biology. Recently, the B-Z transition has been explored from nanotechnological points of view and used as the driving machinery of many nanomechanical devices. Using a combination of CD spectroscopy, fluorescence spectroscopy, and PAGE, we demonstrate that low concentration of lanthanum chloride can mediate B-to-Z transition in self-assembled Y-shaped branched DNA (bDNA) structure. The transition is sensitive to the sequence and structure of the bDNA. Thermal melting and competitive dye binding experiments suggest that La3+ ions are loaded to the major and minor grooves of DNA and stabilize the Z-conformation. Our studies also show that EDTA and EtBr play an active role in reversing the transition from Z-to-B DNA.

Identification of potentially cytotoxic lesions induced by UVA photoactivation of DNA 4-thiothymidine in human cells

PubMed Central

Reelfs, Olivier; Macpherson, Peter; Ren, Xiaolin; Xu, Yao-Zhong; Karran, Peter; Young, Antony R.

2011-01-01

Photochemotherapy—in which a photosensitizing drug is combined with ultraviolet or visible radiation—has proven therapeutic effectiveness. Existing approaches have drawbacks, however, and there is a clinical need to develop alternatives offering improved target cell selectivity. DNA substitution by 4-thiothymidine (S4TdR) sensitizes cells to killing by ultraviolet A (UVA) radiation. Here, we demonstrate that UVA photoactivation of DNA S4TdR does not generate reactive oxygen or cause direct DNA breakage and is only minimally mutagenic. In an organotypic human skin model, UVA penetration is sufficiently robust to kill S4TdR-photosensitized epidermal cells. We have investigated the DNA lesions responsible for toxicity. Although thymidine is the predominant UVA photoproduct of S4TdR in dilute solution, more complex lesions are formed when S4TdR-containing oligonucleotides are irradiated. One of these, a thietane/S5-(6-4)T:T, is structurally related to the (6-4) pyrimidine:pyrimidone [(6-4) Py:Py] photoproducts induced by UVB/C radiation. These lesions are detectable in DNA from S4TdR/UVA-treated cells and are excised from DNA more efficiently by keratinocytes than by leukaemia cells. UVA irradiation also induces DNA interstrand crosslinking of S4TdR-containing duplex oligonucleotides. Cells defective in repairing (6-4) Py:Py DNA adducts or processing DNA crosslinks are extremely sensitive to S4TdR/UVA indicating that these lesions contribute significantly to S4TdR/UVA cytotoxicity. PMID:21890905

Ultraviolet Absorption Induces Hydrogen-Atom Transfer in G⋅C Watson-Crick DNA Base Pairs in Solution.

PubMed

Röttger, Katharina; Marroux, Hugo J B; Grubb, Michael P; Coulter, Philip M; Böhnke, Hendrik; Henderson, Alexander S; Galan, M Carmen; Temps, Friedrich; Orr-Ewing, Andrew J; Roberts, Gareth M

2015-12-01

Ultrafast deactivation pathways bestow photostability on nucleobases and hence preserve the structural integrity of DNA following absorption of ultraviolet (UV) radiation. One controversial recovery mechanism proposed to account for this photostability involves electron-driven proton transfer (EDPT) in Watson-Crick base pairs. The first direct observation is reported of the EDPT process after UV excitation of individual guanine-cytosine (G⋅C) Watson-Crick base pairs by ultrafast time-resolved UV/visible and mid-infrared spectroscopy. The formation of an intermediate biradical species (G[-H]⋅C[+H]) with a lifetime of 2.9 ps was tracked. The majority of these biradicals return to the original G⋅C Watson-Crick pairs, but up to 10% of the initially excited molecules instead form a stable photoproduct G*⋅C* that has undergone double hydrogen-atom transfer. The observation of these sequential EDPT mechanisms across intermolecular hydrogen bonds confirms an important and long debated pathway for the deactivation of photoexcited base pairs, with possible implications for the UV photochemistry of DNA. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Generation and Repair of AID-initiated DNA Lesions in B Lymphocytes

PubMed Central

Chen, Zhangguo; Wang, Jing H.

2014-01-01

Activation-induced deaminase (AID) initiates the secondary antibody diversification process in B lymphocytes. In mammalian B cells, this process includes somatic hypermutation (SHM) and class switch recombination (CSR), both of which require AID. AID induces U:G mismatch lesions in DNA that are subsequently converted into point mutations or DNA double stranded breaks during SHM/CSR. In a physiological context, AID targets immunoglobulin (Ig) loci to mediate SHM/CSR. However, recent studies reveal genome-wide access of AID to numerous non-Ig loci. Thus, AID poses a threat to the genome of B cells if AID-initiated DNA lesions cannot be properly repaired. In this review, we focus on the molecular mechanisms that regulate the specificity of AID targeting and the repair pathways responsible for processing AID-initiated DNA lesions. PMID:24748462

Sulforaphane suppresses ultraviolet B-induced inflammation in HaCaT keratinocytes and HR-1 hairless mice.

PubMed

Shibata, Akira; Nakagawa, Kiyotaka; Yamanoi, Hiroko; Tsuduki, Tsuyoshi; Sookwong, Phumon; Higuchi, Ohki; Kimura, Fumiko; Miyazawa, Teruo

2010-08-01

Ultraviolet B (UVB) irradiation induces skin damage and inflammation. One way to reduce the inflammation is via the use of molecules termed photochemopreventive agents. Sulforaphane (4-methylsulfinylbutyl isothiocyanate, SF), which is found in cruciferous vegetables, is known for its potent physiological properties. This study was designed to evaluate the effect of SF on skin inflammation in vitro and in vivo. In in vitro study using immortalized human keratinocytes (HaCaT), UVB caused marked inflammatory responses [i.e., decrease of HaCaT viability and increase of production of an inflammatory marker interleukin-6 (IL-6)]. SF recovered the cell proliferation and suppressed the IL-6 production. These anti-inflammatory effects of SF were explained by its ability to reduce UVB-induced inflammatory gene expressions [IL-6, IL-1beta and cyclooxgenase-2 (COX-2)]. Because SF seems to have an impact on COX-2 expression, we focused on COX-2 and found that SF reduced UVB-induced COX-2 protein expression. In support of this, PGE(2) released from HaCaT was suppressed by SF. Western blot analysis revealed that SF inhibited p38, ERK and SAPK/JNK activation, indicating that the inhibition of mitogen-activated protein kinases (MAPK) by SF would attenuate the expression of inflammatory mediators (e.g., COX-2), thereby reducing inflammatory responses. Moreover, we conducted skin thickening assay using HR-1 hairless mice and found that UVB-induced skin thickness, COX-2 protein expression and hyperplasia were all suppressed by feeding SF to the mice. These results suggest that SF has a potential use as a compound for protection against UVB-induced skin inflammation. Copyright 2010 Elsevier Inc. All rights reserved.

Ultraviolet-B radiation induces modulation of antigen presentation of herpes simplex virus by human epidermal cells.

PubMed

van der Molen, R G; Out-Luiting, C; Claas, F H; Norval, M; Koerten, H K; Mommaas, A M

2001-06-01

Although ultraviolet (UV) B radiation is known to be immunosuppressive, there is little information regarding a relevant immunological endpoint to assess human subjects in vivo. Therefore, we have examined the effect of in vivo UV radiation on the ability of human epidermal cells (EC) to present herpes simplex virus (HSV) antigens to memory T cells. Human volunteers, who were seropositive for HSV, were exposed to one minimal erythemal dose (MED) for four consecutive days. EC, prepared from suction blister roofs, were co-cultured with autologous T cells in the presence of HSV. HSV antigen presentation by UV-exposed EC was increased compared with control, nonexposed EC. This up-regulation correlated with an influx of macrophages into the epidermis, which are considered to be associated with UV-induced tolerance. Altering the UV protocol to a sub-erythemal UV dose for four consecutive days or to a single high dose of 2 MED, resulted in suppressed HSV antigen presentation, without the influx of the UV-macrophages. One of the goals of the present study was to eventually use this HSV system to investigate sunscreen immunoprotection. A pilot study with a TiO2-containing sunscreen suggested that the endpoint for UV-induced immunosuppression presented here is promising to be used for human in vivo sunscreen immunoprotection studies.

Lycium barbarum Polysaccharides Protect Rat Corneal Epithelial Cells against Ultraviolet B-Induced Apoptosis by Attenuating the Mitochondrial Pathway and Inhibiting JNK Phosphorylation.

PubMed

Du, Shaobo; Han, Biao; Li, Kang; Zhang, Xuan; Sha, Xueli; Gao, Lan

2017-01-01

Lycium barbarum polysaccharides (LBPs) have been shown to play a key role in protecting the eyes by reducing the apoptosis induced by certain types of damage. However, it is not known whether LBPs can protect damaged corneal cells from apoptosis. Moreover, no reports have focused on the role of LBPs in guarding against ultraviolet B- (UVB-) induced apoptosis. The present study aimed to investigate the protective effect and underlying mechanism of LBPs against UVB-induced apoptosis in rat corneal epithelial (RCE) cells. The results showed that LBPs significantly prevented the loss of cell viability and inhibited cell apoptosis induced by UVB in RCE cells. LBPs also inhibited UVB-induced loss of mitochondrial membrane potential, downregulation of Bcl-2 , and upregulation of Bax and caspase-3. Finally, LBPs attenuated the phosphorylation of c-Jun NH 2 -terminal kinase (JNK) triggered by UVB. In summary, LBPs protect RCE cells against UVB-induced damage and apoptosis, and the underlying mechanism involves the attenuation of the mitochondrial apoptosis pathway and the inhibition of JNK phosphorylation.

Chemiexcitation of Melanin Derivatives Induces DNA Photoproducts Long after UV Exposure

PubMed Central

Premi, Sanjay; Wallisch, Silvia; Mano, Camila M.; Weiner, Adam B.; Bacchiocchi, Antonella; Wakamatsu, Kazumasa; Bechara, Etelvino J. H.; Halaban, Ruth; Douki, Thierry; Brash, Douglas E.

2015-01-01

Mutations in sunlight-induced melanoma arise from cyclobutane pyrimidine dimers (CPD), DNA photoproducts that are typically created picoseconds after an ultraviolet (UV) photon is absorbed at thymine or cytosine. Here we show that in melanocytes, CPD are generated for >3 hours after exposure to UVA, a major component of the radiation in sunlight and in tanning beds. These “dark CPD” constitute the majority of CPD and include the cytosine-containing CPD that initiate UV-signature C→T mutations. Dark CPD arise when UV-induced reactive oxygen and nitrogen species combine to excite an electron in fragments of the pigment melanin. This creates a quantum triplet state that has the energy of a UV photon but that induces CPD by energy transfer to DNA in a radiation-independent manner. Melanin may thus be carcinogenic as well as protective against cancer. These findings also validate the long-standing suggestion that chemically-generated excited electronic states are relevant to mammalian biology. PMID:25700512

Genome-Wide Transcriptional Profiling of Skin and Dorsal Root Ganglia after Ultraviolet-B-Induced Inflammation

PubMed Central

Paterson, Kathryn J.; Sisignano, Marco; Schmid, Ramona; Rust, Werner; Hildebrandt, Tobias; Geisslinger, Gerd; Orengo, Christine; Bennett, David L.; McMahon, Stephen B.

2014-01-01

Ultraviolet-B (UVB)-induced inflammation produces a dose-dependent mechanical and thermal hyperalgesia in both humans and rats, most likely via inflammatory mediators acting at the site of injury. Previous work has shown that the gene expression of cytokines and chemokines is positively correlated between species and that these factors can contribute to UVB-induced pain. In order to investigate other potential pain mediators in this model we used RNA-seq to perform genome-wide transcriptional profiling in both human and rat skin at the peak of hyperalgesia. In addition we have also measured transcriptional changes in the L4 and L5 DRG of the rat model. Our data show that UVB irradiation produces a large number of transcriptional changes in the skin: 2186 and 3888 genes are significantly dysregulated in human and rat skin, respectively. The most highly up-regulated genes in human skin feature those encoding cytokines (IL6 and IL24), chemokines (CCL3, CCL20, CXCL1, CXCL2, CXCL3 and CXCL5), the prostanoid synthesising enzyme COX-2 and members of the keratin gene family. Overall there was a strong positive and significant correlation in gene expression between the human and rat (R = 0.8022). In contrast to the skin, only 39 genes were significantly dysregulated in the rat L4 and L5 DRGs, the majority of which had small fold change values. Amongst the most up-regulated genes in DRG were REG3B, CCL2 and VGF. Overall, our data shows that numerous genes were up-regulated in UVB irradiated skin at the peak of hyperalgesia in both human and rats. Many of the top up-regulated genes were cytokines and chemokines, highlighting again their potential as pain mediators. However many other genes were also up-regulated and might play a role in UVB-induced hyperalgesia. In addition, the strong gene expression correlation between species re-emphasises the value of the UVB model as translational tool to study inflammatory pain. PMID:24732968

Solar Simulated Ultraviolet Radiation Induces Global Histone Hypoacetylation in Human Keratinocytes.

PubMed

Zhang, Xiaoru; Kluz, Thomas; Gesumaria, Lisa; Matsui, Mary S; Costa, Max; Sun, Hong

2016-01-01

Ultraviolet radiation (UVR) from sunlight is the primary effector of skin DNA damage. Chromatin remodeling and histone post-translational modification (PTM) are critical factors in repairing DNA damage and maintaining genomic integrity, however, the dynamic changes of histone marks in response to solar UVR are not well characterized. Here we report global changes in histone PTMs induced by solar simulated UVR (ssUVR). A decrease in lysine acetylation of histones H3 and H4, particularly at positions of H3 lysine 9, lysine 56, H4 lysine 5, and lysine 16, was found in human keratinocytes exposed to ssUVR. These acetylation changes were highly associated with ssUVR in a dose-dependent and time-specific manner. Interestingly, H4K16ac, a mark that is crucial for higher order chromatin structure, exhibited a persistent reduction by ssUVR that was transmitted through multiple cell divisions. In addition, the enzymatic activities of histone acetyltransferases were significantly reduced in irradiated cells, which may account for decreased global acetylation. Moreover, depletion of histone deacetylase SIRT1 in keratinocytes rescued ssUVR-induced H4K16 hypoacetylation. These results indicate that ssUVR affects both HDAC and HAT activities, leading to reduced histone acetylation.

Solar Simulated Ultraviolet Radiation Induces Global Histone Hypoacetylation in Human Keratinocytes

PubMed Central

Zhang, Xiaoru; Kluz, Thomas; Gesumaria, Lisa; Matsui, Mary S.; Costa, Max; Sun, Hong

2016-01-01

Ultraviolet radiation (UVR) from sunlight is the primary effector of skin DNA damage. Chromatin remodeling and histone post-translational modification (PTM) are critical factors in repairing DNA damage and maintaining genomic integrity, however, the dynamic changes of histone marks in response to solar UVR are not well characterized. Here we report global changes in histone PTMs induced by solar simulated UVR (ssUVR). A decrease in lysine acetylation of histones H3 and H4, particularly at positions of H3 lysine 9, lysine 56, H4 lysine 5, and lysine 16, was found in human keratinocytes exposed to ssUVR. These acetylation changes were highly associated with ssUVR in a dose-dependent and time-specific manner. Interestingly, H4K16ac, a mark that is crucial for higher order chromatin structure, exhibited a persistent reduction by ssUVR that was transmitted through multiple cell divisions. In addition, the enzymatic activities of histone acetyltransferases were significantly reduced in irradiated cells, which may account for decreased global acetylation. Moreover, depletion of histone deacetylase SIRT1 in keratinocytes rescued ssUVR-induced H4K16 hypoacetylation. These results indicate that ssUVR affects both HDAC and HAT activities, leading to reduced histone acetylation. PMID:26918332

Differential effects of topical vitamin E and C E Ferulic® treatments on ultraviolet light B-induced cutaneous tumor development in Skh-1 mice.

PubMed

Burns, Erin M; Tober, Kathleen L; Riggenbach, Judith A; Kusewitt, Donna F; Young, Gregory S; Oberyszyn, Tatiana M

2013-01-01

Because of the ever-increasing incidence of ultraviolet light B (UVB)-induced skin cancer, considerable attention is being paid to prevention through the use of both sunscreens and after sun treatments, many of which contain antioxidants. Vitamin E is included as an antioxidant in many sunscreens and lotions currently on the market. Studies examining the efficacy of vitamin E as a topical preventative agent for UVB-induced skin cancer have yielded conflicting results. A likely contributor to differences in study outcome is the stability of vitamin E in the particular formulation being tested. In the current study we examined the effects of topical vitamin E alone as well as vitamin E combined with vitamin C and ferulic acid in a more stable topical formula (C E Ferulic®). Mice were exposed to UVB for 10 weeks in order to induce skin damage. Then, before the appearance of any cutaneous lesions, mice were treated for 15 weeks with a topical antioxidant, without any further UVB exposure. We found that topical C E Ferulic decreased tumor number and tumor burden and prevented the development of malignant skin tumors in female mice with chronically UVB-damaged skin. In contrast, female mice chronically exposed to UVB and treated topically with vitamin E alone showed a trend towards increased tumor growth rate and exhibited increased levels of overall DNA damage, cutaneous proliferation, and angiogenesis compared to vehicle-treated mice. Thus, we have demonstrated that topical 5% alpha tocopherol may actually promote carcinogenesis when applied on chronically UVB-damaged skin while treating with a more stable antioxidant compound may offer therapeutic benefits.

NF-κB DNA-binding activity in embryos responding to a teratogen, cyclophosphamide

PubMed Central

Torchinsky, Arkady; Lishanski, Lucy; Wolstein, Orit; Shepshelovich, Jeanne; Orenstein, Hasida; Savion, Shoshana; Zaslavsky, Zeev; Carp, Howard; Brill, Alexander; Dikstein, Rivka; Toder, Vladimir; Fein, Amos

2002-01-01

Background The Rel/NF-κB transcription factors have been shown to regulate apoptosis in different cell types, acting as inducers or blockers in a stimuli- and cell type-dependent fashion. One of the Rel/NF-κB subunits, RelA, has been shown to be crucial for normal embryonic development, in which it functions in the embryonic liver as a protector against TNFα-induced physiological apoptosis. This study assesses whether NF-κB may be involved in the embryo's response to teratogens. Fot this, we evaluated how NF-KappaB DNA binding activity in embryonic organs demonstraiting differential sensitivity to a reference teratogen, cyclophosphamide, correlates with dysmorphic events induced by the teratogen at the cellular level (excessive apoptosis) and at the organ level (structural anomalies). Results The embryonic brain and liver were used as target organs. We observed that the Cyclophosphamide-induced excessive apoptosis in the brain, followed by the formation of severe craniofacial structural anomalies, was accompanied by suppression of NF-κB DNA-binding activity as well as by a significant and lasting increase in the activity of caspases 3 and 8. However, in the liver, in which cyclophosphamide induced transient apoptosis was not followed by dysmorphogenesis, no suppression of NF-κB DNA-binding activity was registered and the level of active caspases 3 and 8 was significantly lower than in the brain. It has also been observed that both the brain and liver became much more sensitive to the CP-induced teratogenic insult if the embryos were exposed to a combined treatment with the teratogen and sodium salicylate that suppressed NF-κB DNA-binding activity in these organs. Conclusion The results of this study demonstrate that suppression of NF-κB DNA-binding activity in embryos responding to the teratogenic insult may be associated with their decreased resistance to this insult. They also suggest that teratogens may suppress NF-κB DNA-binding activity in the

Fisetin inhibits UVB-induced cutaneous inflammation and activation of PI3K/AKT/NFκB signaling pathways in SKH-1 hairless mice†

PubMed Central

Pal, Harish Chandra; Athar, Mohammad; Elmets, Craig A.; Afaq, Farrukh

2014-01-01

Solar ultraviolet B (UVB) radiation has been shown to induce inflammation, DNA damage, p53 mutations, and alterations in signaling pathways eventually leading to skin cancer. In the present study, we investigated whether fisetin reduces inflammatory responses and modulates PI3K/AKT/NFκB cell survival signaling pathways in UVB exposed SKH-1 hairless mouse skin. Mice were exposed to 180 mJ/cm2 of UVB radiation on alternate days for a total of seven exposures, and fisetin (250 and 500 nmol) was applied topically after 15 min of each UVB exposure. Fisetin treatment to UVB exposed mice resulted in decreased hyperplasia and reduced infiltration of inflammatory cells. Fisetin treatment also reduced inflammatory mediators such as COX-2, PGE2 as well as its receptors (EP1- EP4), and MPO activity. Furthermore, fisetin reduced the level of inflammatory cytokines TNFα, IL-1β and IL-6 in UVB exposed skin. Fisetin treatment also reduced cell proliferation markers as well as DNA damage as evidenced by increased expression of p53 and p21 proteins. Further studies revealed that fisetin inhibited UVB-induced expression of PI3K, phosphorylation of AKT, and activation of the NFκB signaling pathway in mouse skin. Overall, these data suggest that fisetin may be useful against UVB-induced cutaneous inflammation and DNA damage. PMID:25169110

Fisetin inhibits UVB-induced cutaneous inflammation and activation of PI3K/AKT/NFκB signaling pathways in SKH-1 hairless mice.

PubMed

Pal, Harish Chandra; Athar, Mohammad; Elmets, Craig A; Afaq, Farrukh

2015-01-01

Solar ultraviolet B (UVB) radiation has been shown to induce inflammation, DNA damage, p53 mutations and alterations in signaling pathways eventually leading to skin cancer. In this study, we investigated whether fisetin reduces inflammatory responses and modulates PI3K/AKT/NFκB cell survival signaling pathways in UVB-exposed SKH-1 hairless mouse skin. Mice were exposed to 180 mJ cm(-2) of UVB radiation on alternate days for a total of seven exposures, and fisetin (250 and 500 nmol) was applied topically after 15 min of each UVB exposure. Fisetin treatment to UVB-exposed mice resulted in decreased hyperplasia and reduced infiltration of inflammatory cells. Fisetin treatment also reduced inflammatory mediators such as COX-2, PGE2 as well as its receptors (EP1-EP4) and MPO activity. Furthermore, fisetin reduced the level of inflammatory cytokines TNFα, IL-1β and IL-6 in UVB-exposed skin. Fisetin treatment also reduced cell proliferation markers as well as DNA damage as evidenced by increased expression of p53 and p21 proteins. Further studies revealed that fisetin inhibited UVB-induced expression of PI3K, phosphorylation of AKT and activation of the NFκB signaling pathway in mouse skin. Overall, these data suggest that fisetin may be useful against UVB-induced cutaneous inflammation and DNA damage. © 2014 The American Society of Photobiology.

Anti-Photoaging Effect of Jeju Putgyul (Unripe Citrus) Extracts on Human Dermal Fibroblasts and Ultraviolet B-induced Hairless Mouse Skin

PubMed Central

Choi, Seung-Hyun; Choi, Sun-Il; Jung, Tae-Dong; Cho, Bong-Yeon; Lee, Jin-Ha; Kim, Seung-Hyung; Yoon, Seon-A; Ham, Young-Min; Yoon, Weon-Jong; Cho, Ju-Hyun; Lee, Ok-Hawn

2017-01-01

Ultraviolet (UV) radiation stimulates the expression of matrix metalloproteinases (MMPs) and inflammatory cytokines. These signaling pathways participate in the degradation of the extracellular matrix and induce inflammatory responses that lead to photoaging. This study evaluated the antioxidant activity and the effect on MMPs and procollagen of putgyul extract in vitro. The anti-photoaging activity of putgyul extracts was estimated in vivo using hairless mice (HR-1). The putgyul extracts reduced MMP-1 production and increased the content of procollagen type I carboxy-terminal peptide in human dermal fibroblasts. Ultravilot-B (UVB)-induced expression of inflammatory cytokines and MMPs was detected in mice, and putgyul extracts suppressed the expression. These results suggest that putgyul extract inhibits photoaging by inhibiting the expression of MMPs that degrade collagen and inhibiting cytokines that induce inflammatory responses. The mouse model also demonstrated that oral administration of putgyul extracts decreased wrinkle depth, epidermal thickness, collagen degradation, and trans-epidermal water loss, and increased β-glucosidase activity on UVB exposed skin. Putgyul extract protects against UVB-induced damage of skin and could be valuable in the prevention of photoaging. PMID:28946661

Moderate salt treatment alleviates ultraviolet-B radiation caused impairment in poplar plants

NASA Astrophysics Data System (ADS)

Ma, Xuan; Ou, Yong-Bin; Gao, Yong-Feng; Lutts, Stanley; Li, Tao-Tao; Wang, Yang; Chen, Yong-Fu; Sun, Yu-Fang; Yao, Yin-An

2016-09-01

The effects of moderate salinity on the responses of woody plants to UV-B radiation were investigated using two Populus species (Populus alba and Populus russkii). Under UV-B radiation, moderate salinity reduced the oxidation pressure in both species, as indicated by lower levels of cellular H2O2 and membrane peroxidation, and weakened the inhibition of photochemical efficiency expressed by O-J-I-P changes. UV-B-induced DNA lesions in chloroplast and nucleus were alleviated by salinity, which could be explained by the higher expression levels of DNA repair system genes under UV-B&salt condition, such as the PHR, DDB2, and MutSα genes. The salt-induced increase in organic osmolytes proline and glycine betaine, afforded more efficient protection against UV-B radiation. Therefore moderate salinity induced cross-tolerance to UV-B stress in poplar plants. It is thus suggested that woody plants growing in moderate salted condition would be less affected by enhanced UV-B radiation than plants growing in the absence of salt. Our results also showed that UV-B signal genes in poplar plants PaCOP1, PaSTO and PaSTH2 were quickly responding to UV-B radiation, but not to salt. The transcripts of PaHY5 and its downstream pathway genes (PaCHS1, PaCHS4, PaFLS1 and PaFLS2) were differently up-regulated by these treatments, but the flavonoid compounds were not involved in the cross-tolerance since their concentration increased to the same extent in both UV-B and combined stresses.

Human B cells fail to secrete type I interferons upon cytoplasmic DNA exposure.

PubMed

Gram, Anna M; Sun, Chenglong; Landman, Sanne L; Oosenbrug, Timo; Koppejan, Hester J; Kwakkenbos, Mark J; Hoeben, Rob C; Paludan, Søren R; Ressing, Maaike E

2017-11-01

Most cells are believed to be capable of producing type I interferons (IFN I) as part of an innate immune response against, for instance, viral infections. In macrophages, IFN I is potently induced upon cytoplasmic exposure to foreign nucleic acids. Infection of these cells with herpesviruses leads to triggering of the DNA sensors interferon-inducible protein 16 (IFI16) and cyclic GMP-AMP (cGAMP) synthase (cGAS). Thereby, the stimulator of interferon genes (STING) and the downstream molecules TANK-binding kinase 1 (TBK1) and interferon regulatory factor 3 (IRF3) are sequentially activated culminating in IFN I secretion. Human gamma-herpesviruses, such as Epstein-Barr virus (EBV), exploit B cells as a reservoir for persistent infection. In this study, we investigated whether human B cells, similar to macrophages, engage the cytoplasmic DNA sensing pathway to induce an innate immune response. We found that the B cells fail to secrete IFN I upon cytoplasmic DNA exposure, although they express the DNA sensors cGAS and IFI16 and the signaling components TBK1 and IRF3. In primary human B lymphocytes and EBV-negative B cell lines, this deficiency is explained by a lack of detectable levels of the central adaptor protein STING. In contrast, EBV-transformed B cell lines did express STING, yet both these lines as well as STING-reconstituted EBV-negative B cells did not produce IFN I upon dsDNA or cGAMP stimulation. Our combined data show that the cytoplasmic DNA sensing pathway is dysfunctional in human B cells. This exemplifies that certain cell types cannot induce IFN I in response to cytoplasmic DNA exposure providing a potential niche for viral persistence. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Protective effect of curcumin against ultraviolet A irradiation‑induced photoaging in human dermal fibroblasts.

PubMed

Liu, Xiaoming; Zhang, Ruizhi; Shi, Haixia; Li, Xiaobo; Li, Yanhong; Taha, Ahmad; Xu, Chunxing

2018-05-01

Ultraviolet (UV) radiation induces DNA damage, oxidative stress, and inflammatory processes in skin, resulting in photoaging. Natural botanicals have gained considerable attention due to their beneficial protection against the harmful effects of UV irradiation. The present study aimed to evaluate the ability of curcumin (Cur) to protect human dermal fibroblasts (HDFs) against ultraviolet A (UVA)‑induced photoaging. HDFs were treated with 0‑10 µM Cur for 2 h and subsequently exposed to various intensities of UVA irradiation. The cell viability and apoptotic rate of HDFs were investigated by MTT and flow cytometry assays, respectively. The effect of UVA and Cur on the formation of reactive oxygen species (ROS), malondialdehyde levels, which are an indicator of ROS, and the levels/activity of antioxidative defense proteins, including glutathione, superoxide dismutase and catalase, were evaluated using 2',7'-dichlorofluorescin diacetate and commercial assay kits. Furthermore, western blotting was performed to determine the levels of proteins associated with endoplasmic reticulum (ER) stress, the apoptotic pathway, inflammation and the collagen synthesis pathway. The results demonstrated that Cur reduced the accumulation of ROS and restored the activity of antioxidant defense enzymes, indicating that Cur minimized the damage induced by UVA irradiation in HDFs. Furthermore, western blot analysis demonstrated that Cur may attenuate UVA‑induced ER stress, inflammation and apoptotic signaling by downregulating the protein expression of glucose‑regulated protein 78, C/EBP‑homologous protein, nuclear factor‑κB and cleaved caspase‑3, while upregulating the expression of Bcl‑2. Additionally, it was demonstrated that Cur may regulate collagen metabolism by decreasing the protein expression of matrix metalloproteinase (MMP)‑1 and MMP‑3, and may promote the repair of cells damaged as a result of UVA irradiation through increasing the protein expression of

Protective effect of curcumin against ultraviolet A irradiation-induced photoaging in human dermal fibroblasts

PubMed Central

Liu, Xiaoming; Zhang, Ruizhi; Shi, Haixia; Li, Xiaobo; Li, Yanhong; Taha, Ahmad; Xu, Chunxing

2018-01-01

Ultraviolet (UV) radiation induces DNA damage, oxidative stress, and inflammatory processes in skin, resulting in photoaging. Natural botanicals have gained considerable attention due to their beneficial protection against the harmful effects of UV irradiation. The present study aimed to evaluate the ability of curcumin (Cur) to protect human dermal fibroblasts (HDFs) against ultraviolet A (UVA)-induced photoaging. HDFs were treated with 0–10 µM Cur for 2 h and subsequently exposed to various intensities of UVA irradiation. The cell viability and apoptotic rate of HDFs were investigated by MTT and flow cytometry assays, respectively. The effect of UVA and Cur on the formation of reactive oxygen species (ROS), malondialdehyde levels, which are an indicator of ROS, and the levels/activity of antioxidative defense proteins, including glutathione, superoxide dismutase and catalase, were evaluated using 2′,7′-dichlorofluorescin diacetate and commercial assay kits. Furthermore, western blotting was performed to determine the levels of proteins associated with endoplasmic reticulum (ER) stress, the apoptotic pathway, inflammation and the collagen synthesis pathway. The results demonstrated that Cur reduced the accumulation of ROS and restored the activity of antioxidant defense enzymes, indicating that Cur minimized the damage induced by UVA irradiation in HDFs. Furthermore, western blot analysis demonstrated that Cur may attenuate UVA-induced ER stress, inflammation and apoptotic signaling by downregulating the protein expression of glucose-regulated protein 78, C/EBP-homologous protein, nuclear factor-κB and cleaved caspase-3, while upregulating the expression of Bcl-2. Additionally, it was demonstrated that Cur may regulate collagen metabolism by decreasing the protein expression of matrix metalloproteinase (MMP)-1 and MMP-3, and may promote the repair of cells damaged as a result of UVA irradiation through increasing the protein expression of transforming

NF-κB inhibition delays DNA damage–induced senescence and aging in mice

PubMed Central

Tilstra, Jeremy S.; Robinson, Andria R.; Wang, Jin; Gregg, Siobhán Q.; Clauson, Cheryl L.; Reay, Daniel P.; Nasto, Luigi A.; St Croix, Claudette M.; Usas, Arvydas; Vo, Nam; Huard, Johnny; Clemens, Paula R.; Stolz, Donna B.; Guttridge, Denis C.; Watkins, Simon C.; Garinis, George A.; Wang, Yinsheng; Niedernhofer, Laura J.; Robbins, Paul D.

2012-01-01

The accumulation of cellular damage, including DNA damage, is thought to contribute to aging-related degenerative changes, but how damage drives aging is unknown. XFE progeroid syndrome is a disease of accelerated aging caused by a defect in DNA repair. NF-κB, a transcription factor activated by cellular damage and stress, has increased activity with aging and aging-related chronic diseases. To determine whether NF-κB drives aging in response to the accumulation of spontaneous, endogenous DNA damage, we measured the activation of NF-κB in WT and progeroid model mice. As both WT and progeroid mice aged, NF-κB was activated stochastically in a variety of cell types. Genetic depletion of one allele of the p65 subunit of NF-κB or treatment with a pharmacological inhibitor of the NF-κB–activating kinase, IKK, delayed the age-related symptoms and pathologies of progeroid mice. Additionally, inhibition of NF-κB reduced oxidative DNA damage and stress and delayed cellular senescence. These results indicate that the mechanism by which DNA damage drives aging is due in part to NF-κB activation. IKK/NF-κB inhibitors are sufficient to attenuate this damage and could provide clinical benefit for degenerative changes associated with accelerated aging disorders and normal aging. PMID:22706308

7-Hydroxycoumarin prevents UVB-induced activation of NF-κB and subsequent overexpression of matrix metalloproteinases and inflammatory markers in human dermal fibroblast cells.

PubMed

Karthikeyan, Ramasamy; Kanimozhi, Govindasamy; Prasad, Nagarajan Rajendra; Agilan, Balupillai; Ganesan, Muthusamy; Mohana, Shanmugham; Srithar, Gunaseelan

2016-08-01

Ultraviolet B (UVB) irradiation alters multiple molecular pathways in the skin, thereby inducing skin damage. Human dermal fibroblasts (HDFa) were subjected to single UVB-irradiation (18mJ/cm(2)) resulting in reactive oxygen species (ROS) generation, oxidative DNA damage and upregulation of nuclear factor kappa B (NF-κB) expression. Further, it has been observed that there was a significant cytokine production (TNF-α and IL-6) in UVB irradiated HDFa cells. Our results show that 7-hydroxycoumarin (7-OHC) prevents UVB-induced activation of NF-κB thereby subsequently preventing the overexpression of TNF-α and IL-6 in HDFa cells. Further, 7-OHC prevents UVB-induced activation of cyclooxygenase-2 (COX-2) expression, an inflammatory mediator in skin cells. Moreover, 7-OHC inhibited mRNA expression pattern of matrix metalloproteinases (MMP-1 and MMP-9) in UVB irradiated skin cells. Furthermore, 7-OHC restored antioxidant status, thereby scavenging the excessively generated ROS; consequently preventing the oxidative DNA damage. It has also been noticed that 7-OHC prevents UVB mediated DNA damage through activation of DNA repair enzymes such as XRCC1 and HOGG1. In this study, we treated HDFa cells with 7-OHC before and after UVB irradiation and we found that pretreatment showed better results when compared to posttreatment. Further, 7-OHC showed 9.8416 sun protection factor (SPF) value and it absorbs photons in the UVB wavelength rage. Thus, it has been concluded that sunscreen property, free radical scavenging potential and prevention of NF-κB activation play a role for photoprotective property of 7-OHC. Copyright © 2016 Elsevier B.V. All rights reserved.

kgp, rgpA, and rgpB DNA vaccines induce antibody responses in experimental peri-implantitis.

PubMed

Guo, Meihua; Wang, Zhifeng; Fan, Xin; Bian, Yuanyuan; Wang, Tiantian; Zhu, Lina; Lan, Jing

2014-11-01

Peri-implantitis is the key factor for implant failure. This study aims to evaluate kgp, rgpA, and rgpB DNA vaccines to induce an immune response and prevent peri-implantitis. The kgp, rgpA, and rgpB genes were amplified by polymerase chain reaction (PCR) from Porphyromonas gingivalis (Pg) ATCC 33277 and cloned into the pVAX1 vector. Titanium implants were placed into the mandibular bone of dogs. Three months later, the animals were divided into four groups, immunized with pVAX1-kgp, pVAX1-rgpA, pVAX1-rgpB, or pVAX1. Cotton ligatures infiltrated with Pg were tied around the neck of the implants. Immunoglobulin (Ig)G and IgA antibodies were detected by enzyme-linked immunosorbent assay before and after immunization. The kgp, rgpA, and rgpB genes were successfully cloned into the pVAX1 plasmid. Animals immunized with pVAX1-kgp and pVAX1-rgpA showed higher titers of IgG and IgA antibodies compared to those before immunization (P <0.05) and compared to those that were immunized with pVAX1 and pVAX1-rgpB, whereas there were no significant differences in the animals treated with pVAX1 and pVAX1-rgpB. Furthermore, among these, the kgp DNA vaccine was more effective. The bone losses of the groups with pVAX1-kgp and pVAX1-rgpA were significantly attenuated. pVAX1-kgp and pVAX1-rgpA DNA vaccines enhanced immunity responses and significantly retarded bone loss in experimental peri-implantitis animal models, whereas pVAX1-rgpB was ineffective.

AID-induced decrease in topoisomerase 1 induces DNA structural alteration and DNA cleavage for class switch recombination.

PubMed

Kobayashi, Maki; Aida, Masatoshi; Nagaoka, Hitoshi; Begum, Nasim A; Kitawaki, Yoko; Nakata, Mikiyo; Stanlie, Andre; Doi, Tomomitsu; Kato, Lucia; Okazaki, Il-mi; Shinkura, Reiko; Muramatsu, Masamichi; Kinoshita, Kazuo; Honjo, Tasuku

2009-12-29

To initiate class switch recombination (CSR) activation-induced cytidine deaminase (AID) induces staggered nick cleavage in the S region, which lies 5' to each Ig constant region gene and is rich in palindromic sequences. Topoisomerase 1 (Top1) controls the supercoiling of DNA by nicking, rotating, and religating one strand of DNA. Curiously, Top1 reduction or AID overexpression causes the genomic instability. Here, we report that the inactivation of Top1 by its specific inhibitor camptothecin drastically blocked both the S region cleavage and CSR, indicating that Top1 is responsible for the S region cleavage in CSR. Surprisingly, AID expression suppressed Top1 mRNA translation and reduced its protein level. In addition, the decrease in the Top1 protein by RNA-mediated knockdown augmented the AID-dependent S region cleavage, as well as CSR. Furthermore, Top1 reduction altered DNA structure of the Smu region. Taken together, AID-induced Top1 reduction alters S region DNA structure probably to non-B form, on which Top1 can introduce nicks but cannot religate, resulting in S region cleavage.

Hereditary Disorders with Defective Repair of UV-Induced DNA Damage

PubMed Central

Moriwaki, Shinichi

2013-01-01

Nucleotide excision repair (NER) is an essential system for correcting ultraviolet (UV)—induced DNA damage. Lesions remaining in DNA due to reduced capacity of NER may result in cellular death, premature aging, mutagenesis and carcinogenesis of the skin. So, NER is an important protection against these changes. There are three representative genodermatoses resulting from genetic defects in NER: xeroderma pigmentosum (XP), Cockayne syndrome (CS), and trichothiodystrophy (TTD). In Japan, CS is similarly rare but XP is more common and TTD is less common compared to Western countries. In 1998, we established the system for the diagnosis of these disorders and we have been performing DNA repair and genetic analysis for more than 400 samples since then. At present, there is no cure for any human genetic disorder. Early diagnosis and symptomatic treatment of neurological, ocular and dermatological abnormalities should contribute to prolonging life and elevating QOL in patients. PMID:23966815

Extreme ultraviolet observations of G191-B2B and the local interstellar medium with the Hopkins Ultraviolet Telescope

NASA Technical Reports Server (NTRS)

Kimble, Randy A.; Davidsen, Arthur F.; Blair, William P.; Bowers, Charles W.; Van Dyke Dixon, W.; Durrance, Samuel T.; Feldman, Paul D.; Ferguson, Henry C.; Henry, Richard C.; Kriss, Gerard A.

1993-01-01

During the Astro-l mission in 1990 December, the Hopkins Ultraviolet Telescope (HUT) was used to observe the extreme ultraviolet spectrum (415-912 A) of the hot DA white dwarf GI91-B2B. Absorption by neutral helium shortward of the 504 A He I absorption edge is clearly detected in the raw spectrum. Model fits to the observed spectrum require interstellar neutral helium and neutral hydrogen column densities of 1.45 +/- 0.065 x 10 exp 17/sq cm and 1.69 +/- 0.12 x 10 exp 18/sq cm, respectively. Comparison of the neutral columns yields a direct assessment of the ionization state of the local interstellar cloud surrounding the Sun. The neutral hydrogen to helium ratio of 11.6 +/- 1.0 observed by HUT strongly contradicts the widespread view that hydrogen is much more ionized than helium in the local interstellar medium, a view which has motivated some exotic theoretical explanations for the supposed high ionization.

Noise Induced DNA Damage Within the Auditory Nerve.

PubMed

Guthrie, O'neil W

2017-03-01

An understanding of the molecular pathology that underlies noise induced neurotoxicity is a prerequisite to the design of targeted therapies. The objective of the current experiment was to determine whether or not DNA damage is part of the pathophysiologic sequela of noise induced neurotoxicity. The experiment consisted of 41 hooded Long-Evans rats (2 month old males) that were randomized into control and noise exposed groups. Both the control and the noise group followed the same time schedule and therefore started and ended the experiment together. The noise dose consisted of a 6000 Hz noise band at 105 dB SPL. Temporal bones from both groups were harvested, and immunohistochemistry was used to identify neurons with DNA damage. Quantitative morphometric analyses was then employed to determine the level of DNA damage. Neural action potentials were recorded to assess the functional impact of noise induced DNA damage. Immunohistochemical reactions revealed that the noise exposure precipitated DNA damage within the nucleus of auditory neurons. Quantitative morphometry confirmed the noise induced increase in DNA damage levels and the precipitation of DNA damage was associated with a significant loss of nerve sensitivity. Therefore, DNA damage is part of the molecular pathology that drives noise induced neurotoxicity. Anat Rec, 300:520-526, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Topical application of spent coffee ground extracts protects skin from ultraviolet B-induced photoaging in hairless mice.

PubMed

Choi, Hyeon-Son; Park, Eu Ddeum; Park, Yooheon; Han, Sung Hee; Hong, Ki Bae; Suh, Hyung Joo

2016-06-08

The aim of this study was to evaluate the protective effect of spent coffee ground (SCG) on ultraviolet (UV) B-induced photoaging in hairless mice. The oil fraction (OSCG) and ethanol extract (ESCG) of SCG were prepared from SCG. OSCG contained a much higher level of caffeine (547.32 ± 1.68 μg mg(-1)) when compared to the sum of its chlorogenic acid derivatives (∼119 μg mg(-1)), and pyrazines were the major aromatic compounds in OSCG. OSCG effectively inhibited the UVB-induced increase in intracellular reactive oxygen species in HaCaT cells. Topical application of OSCG or ESCG significantly reduced the UVB-induced wrinkle formation in mice dorsal skin. The combined application of OSCG and ESCG (OEH) led to a decrease in the wrinkle area by over 35% when compared with the UVB-treated control (UVBC). Epidermal thickness was also reduced by 40%. This result was connected to the significant reduction in transdermal water loss (27%) and erythema formation (48%) that result from UVB irradiation. Polarization-sensitive optical coherence tomography (PS-OCT) and antibody-based histological analyses showed that OSCG and ESCG effectively suppressed the UVB-induced decrease in collagen content. The level of type 1 collagen (COL1) in the OEH group was enhanced by around 40% compared with the UVB control group (UVBC). This was attributed to the down-regulation of matrix metalloproteinases (MMP2, 9, and 13), which are known to be responsible for collagen destruction. Our results indicate that topical treatment with OSCG/ESCG protects mouse skin from UVB-induced photoaging by down-regulating MMPs; therefore, suggesting the potential of SCG extracts as a topical anti-photoaging agent.

Escherichia coli DinB inhibits replication fork progression without significantly inducing the SOS response.

PubMed

Mori, Tetsuya; Nakamura, Tatsuro; Okazaki, Naoto; Furukohri, Asako; Maki, Hisaji; Akiyama, Masahiro Tatsumi

2012-01-01

The SOS response is readily triggered by replication fork stalling caused by DNA damage or a dysfunctional replicative apparatus in Escherichia coli cells. E. coli dinB encodes DinB DNA polymerase and its expression is upregulated during the SOS response. DinB catalyzes translesion DNA synthesis in place of a replicative DNA polymerase III that is stalled at a DNA lesion. We showed previously that DNA replication was suppressed without exogenous DNA damage in cells overproducing DinB. In this report, we confirm that this was due to a dose-dependent inhibition of ongoing replication forks by DinB. Interestingly, the DinB-overproducing cells did not significantly induce the SOS response even though DNA replication was perturbed. RecA protein is activated by forming a nucleoprotein filament with single-stranded DNA, which leads to the onset of the SOS response. In the DinB-overproducing cells, RecA was not activated to induce the SOS response. However, the SOS response was observed after heat-inducible activation in strain recA441 (encoding a temperature-sensitive RecA) and after replication blockage in strain dnaE486 (encoding a temperature-sensitive catalytic subunit of the replicative DNA polymerase III) at a non-permissive temperature when DinB was overproduced in these cells. Furthermore, since catalytically inactive DinB could avoid the SOS response to a DinB-promoted fork block, it is unlikely that overproduced DinB takes control of primer extension and thus limits single-stranded DNA. These observations suggest that DinB possesses a feature that suppresses DNA replication but does not abolish the cell's capacity to induce the SOS response. We conclude that DinB impedes replication fork progression in a way that does not activate RecA, in contrast to obstructive DNA lesions and dysfunctional replication machinery.

Light-induced pyroelectric effect as an effective approach for ultrafast ultraviolet nanosensing

NASA Astrophysics Data System (ADS)

Wang, Zhaona; Yu, Ruomeng; Pan, Caofeng; Li, Zhaoling; Yang, Jin; Yi, Fang; Wang, Zhong Lin

2015-09-01

Zinc oxide is potentially a useful material for ultraviolet detectors; however, a relatively long response time hinders practical implementation. Here by designing and fabricating a self-powered ZnO/perovskite-heterostructured ultraviolet photodetector, the pyroelectric effect, induced in wurtzite ZnO nanowires on ultraviolet illumination, has been utilized as an effective approach for high-performance photon sensing. The response time is improved from 5.4 s to 53 μs at the rising edge, and 8.9 s to 63 μs at the falling edge, with an enhancement of five orders in magnitudes. The specific detectivity and the responsivity are both enhanced by 322%. This work provides a novel design to achieve ultrafast ultraviolet sensing at room temperature via light-self-induced pyroelectric effect. The newly designed ultrafast self-powered ultraviolet nanosensors may find promising applications in ultrafast optics, nonlinear optics, optothermal detections, computational memories and biocompatible optoelectronic probes.

Plasma Rich in Growth Factors Inhibits Ultraviolet B Induced Photoageing of the Skin in Human Dermal Fibroblast Culture.

PubMed

Anitua, Eduardo; Pino, Ander; Orive, Gorka

Ultraviolet irradiation is able to deeply penetrate into the dermis and alter fibroblast structure and function, leading to a degradation of the dermal extracellular matrix. The regenerative effect of plasma rich in growth factors (PRGF) on skin ageing was investigated using UVB photo-stressed human dermal fibroblasts as an in vitro culture model. PRGF was assessed over the main indicative features of ultraviolet B irradiation, including ROS formation, cell viability and death detection, apoptosis/ necrosis analysis and biosynthetic activity measurement. Four different UV irradiation protocols were tested in order to analyze the beneficial effects of PRGF. Ultraviolet irradiation exhibited a dose dependent cytotoxicity and dose of 400mJ/cm2 was selected for subsequent experiments. PRGF increased the cell viability and decreased the cell death comparing to the non-treated group. The apoptosis and necrosis were significantly lower in PRGF treated fibroblasts. ROS production after UV irradiation was significantly reduced in the presence of PRGF. Procollagen type I, hyaluronic acid and TIMP-1 levels were higher in the when treated with PRGF. This preliminary in vitro study suggests that PRGF is able to prevent UVB derived photooxidative stress and to diminish the cell damage caused by ultraviolet irradiation.

Low concentration of arsenite exacerbates UVR-induced DNA strand breaks by inhibiting PARP-1 activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qin Xujun; Department of Toxicology, Fourth Military Medical University, Xi'an, Shaanxi, 710032; Hudson, Laurie G.

2008-10-01

Epidemiological studies have associated arsenic exposure with many types of human cancers. Arsenic has also been shown to act as a co-carcinogen even at low concentrations. However, the precise mechanism of its co-carcinogenic action is unknown. Recent studies indicate that arsenic can interfere with DNA-repair processes. Poly(ADP-ribose) polymerase (PARP)-1 is a zinc-finger DNA-repair protein, which can promptly sense DNA strand breaks and initiate DNA-repair pathways. In the present study, we tested the hypothesis that low concentrations of arsenic could inhibit PAPR-1 activity and so exacerbate levels of ultraviolet radiation (UVR)-induced DNA strand breaks. HaCat cells were treated with arsenite and/ormore » UVR, and then DNA strand breaks were assessed by comet assay. Low concentrations of arsenite ({<=} 2 {mu}M) alone did not induce significant DNA strand breaks, but greatly enhanced the DNA strand breaks induced by UVR. Further studies showed that 2 {mu}M arsenite effectively inhibited PARP-1 activity. Zinc supplementation of arsenite-treated cells restored PARP-1 activity and significantly diminished the exacerbating effect of arsenite on UVR-induced DNA strand breaks. Importantly, neither arsenite treatment, nor zinc supplementation changed UVR-triggered reactive oxygen species (ROS) formation, suggesting that their effects upon UVR-induced DNA strand breaks are not through a direct free radical mechanism. Combination treatments of arsenite with PARP-1 inhibitor 3-aminobenzamide or PARP-1 siRNA demonstrate that PARP-1 is the target of arsenite. Together, these findings show that arsenite at low concentration exacerbates UVR-induced DNA strand breaks by inhibiting PARP-1 activity, which may represent an important mechanism underlying the co-carcinogenicity of arsenic.« less

Stress-Induced Sleep After Exposure to Ultraviolet Light Is Promoted by p53 in Caenorhabditis elegans.

PubMed

DeBardeleben, Hilary K; Lopes, Lindsey E; Nessel, Mark P; Raizen, David M

2017-10-01

Stress-induced sleep (SIS) in Caenorhabditis elegans is important for restoration of cellular homeostasis and is a useful model to study the function and regulation of sleep. SIS is triggered when epidermal growth factor (EGF) activates the ALA neuron, which then releases neuropeptides to promote sleep. To further understand this behavior, we established a new model of SIS using irradiation by ultraviolet C (UVC) light. While UVC irradiation requires ALA signaling and leads to a sleep state similar to that induced by heat and other stressors, it does not induce the proteostatic stress seen with heat exposure. Based on the known genotoxic effects of UVC irradiation, we tested two genes, atl-1 and cep-1 , which encode proteins that act in the DNA damage response pathway. Loss-of-function mutants of atl-1 had no defect in UVC-induced SIS but a partial loss-of-function mutant of cep-1 , gk138 , had decreased movement quiescence following UVC irradiation. Germline ablation experiments and tissue-specific RNA interference experiments showed that cep-1 is required somatically in neurons for its effect on SIS. The cep-1 ( gk138 ) mutant suppressed body movement quiescence controlled by EGF, indicating that CEP-1 acts downstream or in parallel to ALA activation to promote quiescence in response to ultraviolet light. Copyright © 2017 by the Genetics Society of America.

DNA damage induced by boron neutron capture therapy is partially repaired by DNA ligase IV.

PubMed

Kondo, Natsuko; Sakurai, Yoshinori; Hirota, Yuki; Tanaka, Hiroki; Watanabe, Tsubasa; Nakagawa, Yosuke; Narabayashi, Masaru; Kinashi, Yuko; Miyatake, Shin-ichi; Hasegawa, Masatoshi; Suzuki, Minoru; Masunaga, Shin-ichiro; Ohnishi, Takeo; Ono, Koji

2016-03-01

Boron neutron capture therapy (BNCT) is a particle radiation therapy that involves the use of a thermal or epithermal neutron beam in combination with a boron ((10)B)-containing compound that specifically accumulates in tumor. (10)B captures neutrons and the resultant fission reaction produces an alpha ((4)He) particle and a recoiled lithium nucleus ((7)Li). These particles have the characteristics of high linear energy transfer (LET) radiation and therefore have marked biological effects. High-LET radiation is a potent inducer of DNA damage, specifically of DNA double-strand breaks (DSBs). The aim of the present study was to clarify the role of DNA ligase IV, a key player in the non-homologous end-joining repair pathway, in the repair of BNCT-induced DSBs. We analyzed the cellular sensitivity of the mouse embryonic fibroblast cell lines Lig4-/- p53-/- and Lig4+/+ p53-/- to irradiation using a thermal neutron beam in the presence or absence of (10)B-para-boronophenylalanine (BPA). The Lig4-/- p53-/- cell line had a higher sensitivity than the Lig4+/+ p53-/-cell line to irradiation with the beam alone or the beam in combination with BPA. In BNCT (with BPA), both cell lines exhibited a reduction of the 50 % survival dose (D 50) by a factor of 1.4 compared with gamma-ray and neutron mixed beam (without BPA). Although it was found that (10)B uptake was higher in the Lig4+/+ p53-/- than in the Lig4-/- p53-/- cell line, the latter showed higher sensitivity than the former, even when compared at an equivalent (10)B concentration. These results indicate that BNCT-induced DNA damage is partially repaired using DNA ligase IV.

Effects of early life exposure to ultraviolet C radiation on mitochondrial DNA content, transcription, ATP production, and oxygen consumption in developing Caenorhabditis elegans

PubMed Central

2013-01-01

Background Mitochondrial DNA (mtDNA) is present in multiple copies per cell and undergoes dramatic amplification during development. The impacts of mtDNA damage incurred early in development are not well understood, especially in the case of types of mtDNA damage that are irreparable, such as ultraviolet C radiation (UVC)-induced photodimers. Methods We exposed first larval stage nematodes to UVC using a protocol that results in accumulated mtDNA damage but permits nuclear DNA (nDNA) repair. We then measured the transcriptional response, as well as oxygen consumption, ATP levels, and mtDNA copy number through adulthood. Results Although the mtDNA damage persisted to the fourth larval stage, we observed only a relatively minor ~40% decrease in mtDNA copy number. Transcriptomic analysis suggested an inhibition of aerobic metabolism and developmental processes; mRNA levels for mtDNA-encoded genes were reduced ~50% at 3 hours post-treatment, but recovered and, in some cases, were upregulated at 24 and 48 hours post-exposure. The mtDNA polymerase γ was also induced ~8-fold at 48 hours post-exposure. Moreover, ATP levels and oxygen consumption were reduced in response to UVC exposure, with marked reductions of ~50% at the later larval stages. Conclusions These results support the hypothesis that early life exposure to mitochondrial genotoxicants could result in mitochondrial dysfunction at later stages of life, thereby highlighting the potential health hazards of time-delayed effects of these genotoxicants in the environment. PMID:23374645

Anti-photoaging properties of the phosphodiesterase 3 inhibitor cilostazol in ultraviolet B-irradiated hairless mice.

PubMed

Kim, Ha Neui; Gil, Chan Hee; Kim, Yu Ri; Shin, Hwa Kyoung; Choi, Byung Tae

2016-08-03

We investigated whether cilostazol, an activator of cyclic adenosine monophosphate (cAMP)-dependent intracellular signaling, could inhibit ultraviolet B (UVB) irradiation-induced photoaging in HR-1 hairless mice. Cilostazol decreased wrinkle formation and skin thickness in UVB-irradiated mice, as well as increased staining of collagen fibers and inhibition of reactive oxygen species (ROS) formation in the skin. Moreover, the proteolytic activities of gelatinase matrix metalloproteinase (MMP)-9 and collagenase MMP-3 were significantly decreased in UVB-irradiated mice treated with cilostazol. Western blotting showed that UVB-induced activation of p38 mitogen-activated protein kinases (MAPK) and nuclear factor (NF)-κB was significantly inhibited by cilostazol, whereas the activation of Akt was significantly enhanced by cilostazol. Confirmation of localized protein expression in the skin revealed marked p38 MAPK and NF-κB activation that was mainly detected in the dermis. Marked Akt activation was mainly detected in the epidermis. Our results suggest that cilostazol may have anti-photoaging effects on UVB-induced wrinkle formation by maintaining the extracellular matrix density in the dermis, which occurs via regulation of ROS and related p38 MAPK and NF-κB signaling, and subsequent down-regulation of MMPs. Therefore, cilostazol may protect against photoaging-induced wrinkle formation.

Anti-photoaging properties of the phosphodiesterase 3 inhibitor cilostazol in ultraviolet B-irradiated hairless mice

PubMed Central

Kim, Ha Neui; Gil, Chan Hee; Kim, Yu Ri; Shin, Hwa Kyoung; Choi, Byung Tae

2016-01-01

We investigated whether cilostazol, an activator of cyclic adenosine monophosphate (cAMP)-dependent intracellular signaling, could inhibit ultraviolet B (UVB) irradiation-induced photoaging in HR-1 hairless mice. Cilostazol decreased wrinkle formation and skin thickness in UVB-irradiated mice, as well as increased staining of collagen fibers and inhibition of reactive oxygen species (ROS) formation in the skin. Moreover, the proteolytic activities of gelatinase matrix metalloproteinase (MMP)-9 and collagenase MMP-3 were significantly decreased in UVB-irradiated mice treated with cilostazol. Western blotting showed that UVB-induced activation of p38 mitogen-activated protein kinases (MAPK) and nuclear factor (NF)-κB was significantly inhibited by cilostazol, whereas the activation of Akt was significantly enhanced by cilostazol. Confirmation of localized protein expression in the skin revealed marked p38 MAPK and NF-κB activation that was mainly detected in the dermis. Marked Akt activation was mainly detected in the epidermis. Our results suggest that cilostazol may have anti-photoaging effects on UVB-induced wrinkle formation by maintaining the extracellular matrix density in the dermis, which occurs via regulation of ROS and related p38 MAPK and NF-κB signaling, and subsequent down-regulation of MMPs. Therefore, cilostazol may protect against photoaging-induced wrinkle formation. PMID:27484958

Emamectin benzoate induces ROS-mediated DNA damage and apoptosis in Trichoplusia Tn5B1-4 cells.

PubMed

Luan, Shaorong; Yun, Xinming; Rao, Wenbing; Xiao, Ciying; Xu, Zhikang; Lang, Jialin; Huang, Qingchun

2017-08-01

Emamectin benzoate (EMB), a novel macrocyclic lactone insecticide, possesses high efficacy and beneficial selective toxicity in agriculture, but so far the EMB-induced cytotoxic action in arthropod insect remains unclear. The present studies were carried out to characterize the property of EMB on the induction of reactive oxygen species (ROS)-mediated DNA damage and apoptosis in Trichoplusia Tn5B1-4 cell model. Following the exposure to EMB at 2.5, 5, 10 or 15 μM, the cells changed to be round, suspended and aggregated, and the decline of cell proliferating ability and cell viability was positively related with the exposure time. Median inhibitory concentration (IC 50 ) of EMB on cell viability was 3.72 μM during 72 h exposure. Apoptosis was induced in 29.8% (24 h) and 39.5% (48 h) of the cells by EMB at 15 μM, showing chromatin condensation in nuclei. The content of ROS in the cells increased rapidly as the concentration of EMB increased, and the pre-incubation of the cells with vitamin E significantly reduced the ROS accumulation. In the treatment of 15 μM EMB, the migrated cell nucleus with DNA strand breaks appeared a teardrop, pear-shaped, or large fan-like tail, and 63.1% of γH2AX-positive cells contained more than four foci, accompanying with high expression level of caspase-3 in time-dependent manner, which consequently led to cell apoptotic death. These evidences in ROS-mediated DNA damage and cell apoptosis induced by EMB may be helpful for deep understanding the cytotoxic action of EMB based on cell model. Copyright © 2017 Elsevier B.V. All rights reserved.

Acetaminophen-induced hepatotoxicity is associated with early changes in NF-kB and NF-IL6 DNA binding activity.

PubMed

Blazka, M E; Germolec, D R; Simeonova, P; Bruccoleri, A; Pennypacker, K R; Luster, M I

Nuclear transcription factors, such as NF-kB and NF-IL6, are believed to play an important role in regulating the expression of genes that encode for products involved in tissue damage and inflammation and, thus, may represent early biomarkers for chemical toxicities. In the present study changes in DNA binding activity of these factors were examined in livers of mice administered hepatotoxic doses of acetaminophen (APAP). NF-kB and NF-IL6 DNA binding occurred constitutively in control mouse liver. However, within 4 hr following administration of hepatotoxic doses of APAP, their binding activities were transiently lost and is in contrast to AP-1 transcription factor where activation occurs under similar conditions. These changes corresponded with increased release of inflammatory mediators (IL-6, serum amyloid A) and increased levels of enzymatic markers of hepatocyte damage. Similarly, treatment of mice with gadolinium chloride, an inhibitor of Kupffer cell activation and known to protect against APAP-induced hepatotoxicity, reduced the observed pathophysiological response in the liver while altering the APAP-associated changes in NF-kB DNA binding activity. NF-kB was found predominantly in parenchymal and endothelial cells and was composed primarily of relatively inactive p50 homodimer subunits in control liver. Taken together, these studies suggest that hepatotoxicity is associated with early and complex changes in DNA binding activities of specific transcription factors. In particular, NF-kB and NF-IL6 may serve as negative regulators of hepatocyte-derived inflammatory mediators and is analogous to that previously observed in certain other cell systems such as B lymphocytes.

Cerium chloride stimulated controlled conversion of B-to-Z DNA in self-assembled nanostructures.

PubMed

Bhanjadeo, Madhabi M; Nayak, Ashok K; Subudhi, Umakanta

2017-01-22

DNA adopts different conformation not only because of novel base pairs but also while interacting with inorganic or organic compounds. Self-assembled branched DNA (bDNA) structures or DNA origami that change conformation in response to environmental cues hold great promises in sensing and actuation at the nanoscale. Recently, the B-Z transition in DNA is being explored to design various nanomechanical devices. In this communication we have demonstrated that Cerium chloride binds to the phosphate backbone of self-assembled bDNA structure and induce B-to-Z transition at physiological concentration. The mechanism of controlled conversion from right-handed to left-handed has been assayed by various dye binding studies using CD and fluorescence spectroscopy. Three different bDNA structures have been identified to display B-Z transition. This approach provides a rapid and reversible means to change bDNA conformation, which can be used for dynamic and progressive control at the nanoscale. Copyright © 2016 Elsevier Inc. All rights reserved.

Ultraviolet-B radiation induced crosslinking improves physical properties of cold- and warm-water fish gelatin gels and films

USDA-ARS?s Scientific Manuscript database

Cold- and warm-water fish gelatin granules were exposed to ultraviolet-B radiation for doses up to 29.7 J/cm2. Solutions and films were prepared from the granules. Gel electrophoresis and refractive index were used to examine changes in molecular weight of the samples. Also, the gel strength and rhe...

DNA's Encounter with Ultraviolet Light: An Instinct for Self-Preservation?

PubMed

Barlev, Adam; Sen, Dipankar

2018-02-20

Photochemical modification is the major class of environmental damage suffered by DNA, the genetic material of all free-living organisms. Photolyases are enzymes that carry out direct photochemical repair (photoreactivation) of covalent pyrimidine dimers formed in DNA from exposure to ultraviolet light. The discovery of catalytic RNAs in the 1980s led to the "RNA world hypothesis", which posits that early in evolution RNA or a similar polymer served both genetic and catalytic functions. Intrigued by the RNA world hypothesis, we set out to test whether a catalytic RNA (or a surrogate, a catalytic DNA) with photolyase activity could be contemplated. In vitro selection from a random-sequence DNA pool yielded two DNA enzymes (DNAzymes): Sero1C, which requires serotonin as an obligate cofactor, and UV1C, which is cofactor-independent and optimally uses light of 300-310 nm wavelength to repair cyclobutane thymine dimers within a gapped DNA substrate. Both Sero1C and UV1C show multiple turnover kinetics, and UV1C repairs its substrate with a quantum yield of ∼0.05, on the same order as the quantum yields of certain classes of photolyase enzymes. Intensive study of UV1C has revealed that its catalytic core consists of a guanine quadruplex (G-quadruplex) positioned proximally to the bound substrate's thymine dimer. We hypothesize that electron transfer from photoexcited guanines within UV1C's G-quadruplex is responsible for substrate photoreactivation, analogous to electron transfer to pyrimidine dimers within a DNA substrate from photoexcited flavin cofactors located within natural photolyase enzymes. Though the analogy to evolution is necessarily limited, a comparison of the properties of UV1C and Sero1C, which arose out of the same in vitro selection experiment, reveals that although the two DNAzymes comparably accelerate the rate of thymine dimer repair, Sero1C has a substantially broader substrate repertoire, as it can repair many more kinds of pyrimidine dimers than

Detection of parvovirus B19 DNA in blood: Viruses or DNA remnants?

PubMed

Molenaar-de Backer, M W A; Russcher, A; Kroes, A C M; Koppelman, M H G M; Lanfermeijer, M; Zaaijer, H L

2016-11-01

Parvovirus B19 (B19V) DNA can be detected in blood over a long period after acute infection. Several reports associate the presence of B19V DNA with disease, irrespective of timing of the initial B19V infection. This study aims to analyze the properties of B19V DNA in blood, differentiating between bare, non-infectious strands of DNA and B19V DNA in viable virions. Ten blood donors with asymptomatic acute B19V infection were followed and sampled up to 22 months after infection. The samples were treated with and without an endonuclease and tested for B19V DNA, to distinguish between DNA in virions and naked DNA. In the acute phase of infection, high levels of B19V DNA were detected, concurrent with B19V IgM antibodies. B19V DNA apparently was encapsidated, as indicated by resistance to endonuclease degradation. Subsequently, B19V DNA remained detectable for more than one year in all donors at low levels (<10 5 IU/mL). Approximately 150days after infection B19V DNA became degradable by an endonuclease, indicating that this concerned naked DNA. In some donors a second endonuclease-resistant peak occurred. Detection of B19V DNA in blood by PCR does not necessarily imply that B19V replication takes place and that infectious B19V virions are present. We propose that remnant B19V DNA strands can be released from tissues without active replication. This finding urges to reconsider an assumed role of B19V infection mainly based on B19V DNA detection in blood, a much debated subject in clinical syndromes such as myocarditis and arthritis. Copyright © 2016 Elsevier B.V. All rights reserved.

Nuclear DNA damage-triggered NLRP3 inflammasome activation promotes UVB-induced inflammatory responses in human keratinocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hasegawa, Tatsuya, E-mail: tatsuya.hasegawa@to.shiseido.co.jp; Nakashima, Masaya; Suzuki, Yoshiharu

Ultraviolet (UV) radiation in sunlight can result in DNA damage and an inflammatory reaction of the skin commonly known as sunburn, which in turn can lead to cutaneous tissue disorders. However, little has been known about how UV-induced DNA damage mediates the release of inflammatory mediators from keratinocytes. Here, we show that UVB radiation intensity-dependently increases NLRP3 gene expression and IL-1β production in human keratinocytes. Knockdown of NLRP3 with siRNA suppresses UVB-induced production of not only IL-1β, but also other inflammatory mediators, including IL-1α, IL-6, TNF-α, and PGE{sub 2}. In addition, inhibition of DNA damage repair by knockdown of XPA,more » which is a major component of the nucleotide excision repair system, causes accumulation of cyclobutane pyrimidine dimer (CPD) and activation of NLRP3 inflammasome. In vivo immunofluorescence analysis confirmed that NLRP3 expression is also elevated in UV-irradiated human epidermis. Overall, our findings indicate that UVB-induced DNA damage initiates NLRP3 inflammasome activation, leading to release of various inflammatory mediators from human keratinocytes. - Highlights: • UVB radiation induces NLRP3 inflammasome activation in human keratinocytes. • NLRP3 knockdown suppresses production of UVB-induced inflammatory mediators. • UVB-induced DNA damage triggers NLRP3 inflammasome activation. • NLRP3 expression in human epidermis is elevated in response to UV radiation.« less

Effects of different levels of vitamin C on UV radiation-induced DNA damage

NASA Astrophysics Data System (ADS)

Zhou, Dianfeng; Heng, Hang; Ji, Kang; Ke, Weizhong

2005-05-01

The Raman spectra of DNA in different levels of vitamin C with 10- and 30-min ultraviolet (UV) radiations were reported. The intensity of UV radiation was 18.68 W/m2. The experimental results proved that vitamin C could alone prevent UV radiation from damaging DNA, but the effects depended on the concentration of vitamin C. When the concentration of vitamin C was about 0.08-0.4 mmol/L, vitamin C decreased UV radiation-induced DNA's damage. When the concentration of vitamin C exceeded 0.4 mmol/L, vitamin C accelerated DNA's damage instead. Maybe the reason is that when DNA in aqueous solution is radiated by UV, free radicals come into being, and vitamin C can scavenge free radicals, so vitamin C in lower concentration can protect DNA. The quantity of free radicals is finite, when vitamin C is superfluous, free radicals have been scavenged absolutely and vitamin C is residual. Vitamin C is a strong reductant. When the mixture of DNA and residual vitamin C is radiated by UV, vitamin C reacts with DNA. The more residual vitamin C and the longer time of UV radiation, the more DNA is damaged.

The sequence specificity of UV-induced DNA damage in a systematically altered DNA sequence.

PubMed

Khoe, Clairine V; Chung, Long H; Murray, Vincent

2018-06-01

The sequence specificity of UV-induced DNA damage was investigated in a specifically designed DNA plasmid using two procedures: end-labelling and linear amplification. Absorption of UV photons by DNA leads to dimerisation of pyrimidine bases and produces two major photoproducts, cyclobutane pyrimidine dimers (CPDs) and pyrimidine(6-4)pyrimidone photoproducts (6-4PPs). A previous study had determined that two hexanucleotide sequences, 5'-GCTC*AC and 5'-TATT*AA, were high intensity UV-induced DNA damage sites. The UV clone plasmid was constructed by systematically altering each nucleotide of these two hexanucleotide sequences. One of the main goals of this study was to determine the influence of single nucleotide alterations on the intensity of UV-induced DNA damage. The sequence 5'-GCTC*AC was designed to examine the sequence specificity of 6-4PPs and the highest intensity 6-4PP damage sites were found at 5'-GTTC*CC nucleotides. The sequence 5'-TATT*AA was devised to investigate the sequence specificity of CPDs and the highest intensity CPD damage sites were found at 5'-TTTT*CG nucleotides. It was proposed that the tetranucleotide DNA sequence, 5'-YTC*Y (where Y is T or C), was the consensus sequence for the highest intensity UV-induced 6-4PP adduct sites; while it was 5'-YTT*C for the highest intensity UV-induced CPD damage sites. These consensus tetranucleotides are composed entirely of consecutive pyrimidines and must have a DNA conformation that is highly productive for the absorption of UV photons. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

ADA-07 Suppresses Solar Ultraviolet-Induced Skin Carcinogenesis by Directly Inhibiting TOPK.

PubMed

Gao, Ge; Zhang, Tianshun; Wang, Qiushi; Reddy, Kanamata; Chen, Hanyong; Yao, Ke; Wang, Keke; Roh, Eunmiri; Zykova, Tatyana; Ma, Weiya; Ryu, Joohyun; Curiel-Lewandrowski, Clara; Alberts, David; Dickinson, Sally E; Bode, Ann M; Xing, Ying; Dong, Zigang

2017-09-01

Cumulative exposure to solar ultraviolet (SUV) irradiation is regarded as the major etiologic factor in the development of skin cancer. The activation of the MAPK cascades occurs rapidly and is vital in the regulation of SUV-induced cellular responses. The T-LAK cell-originated protein kinase (TOPK), an upstream activator of MAPKs, is heavily involved in inflammation, DNA damage, and tumor development. However, the chemopreventive and therapeutic effects of specific TOPK inhibitors in SUV-induced skin cancer have not yet been elucidated. In the current study, ADA-07, a novel TOPK inhibitor, was synthesized and characterized. Pull-down assay results, ATP competition, and in vitro kinase assay data revealed that ADA-07 interacted with TOPK at the ATP-binding pocket and inhibited its kinase activity. Western blot analysis showed that ADA-07 suppressed SUV-induced phosphorylation of ERK1/2, p38, and JNKs and subsequently inhibited AP-1 activity. Importantly, topical treatment with ADA-07 dramatically attenuated tumor incidence, multiplicity, and volume in SKH-1 hairless mice exposed to chronic SUV. Our findings suggest that ADA-07 is a promising chemopreventive or potential therapeutic agent against SUV-induced skin carcinogenesis that acts by specifically targeting TOPK. Mol Cancer Ther; 16(9); 1843-54. ©2017 AACR . ©2017 American Association for Cancer Research.

Comparison of potential protection conferred by three immunization strategies (protein/protein, DNA/DNA, and DNA/protein) against Brucella infection using Omp2b in BALB/c Mice.

PubMed

Golshani, Maryam; Rafati, Sima; Nejati-Moheimani, Mehdi; Ghasemian, Melina; Bouzari, Saeid

2016-12-25

In the present study, immunogenicity and protective efficacy of the Brucella outer membrane protein 2b (Omp2b) was evaluated in BALB/c mice using Protein/Protein, DNA/DNA and DNA/Protein vaccine strategies. Immunization of mice with three vaccine regimens elicited a strong specific IgG response (higher IgG2a titers over IgG1 titers) and provided Th1-oriented immune response. Vaccination of BALB/c mice with the DNA/Pro regimen induced higher levels of IFN-γ/IL-2 and conferred more protection levels against B. melitenisis and B. abortus challenge than did the protein or DNA alone. In conclusion, Omp2b is able to stimulate specific immune responses and to confer cross protection against B. melitensis and B. abortus infection. Therefore, it could be introduced as a new potential candidate for the development of a subunit vaccine against Brucella infection. Copyright © 2016 Elsevier B.V. All rights reserved.

Oral administration of Lactobacillus plantarum HY7714 protects hairless mouse against ultraviolet B-induced photoaging.

PubMed

Kim, Hyun Mee; Lee, Dong Eun; Park, Soo Dong; Kim, Yong-Tae; Kim, Yu Jin; Jeong, Ji Woong; Jang, Sung Sik; Ahn, Young-Tae; Sim, Jae-Hun; Huh, Chul-Sung; Chung, Dae Kyun; Lee, Jung-Hee

2014-11-28

Ultraviolet (UV) irradiation alters multiple molecular pathways in the skin, thereby inducing skin damage, including photoaging. In recent years, probiotics have gained interest due to their beneficial effects on skin health, such as inhibiting atopic dermatitis and improving skin immunity or inflammation. However, little is known about the effects of probiotics on UVBinduced photoaging. In this study, we evaluated the effect of Lactobacillus plantarum HY7714 against UVB-induced photoaging in human dermal fibroblasts and hairless mice. The results showed that L. plantarum HY7714 treatment effectively rescued UVB-reduced procollagen expression through the inhibition of UVB-induced matrix metalloproteinase (MMP)-1 expression in human dermal fibroblasts. Data from a western blot showed that L. plantarum HY7714 inhibited the phosphorylation of Jun N-terminal kinase, thereby suppressing the UVB-induced phosphorylation and expression of c-Jun. Oral administration of L. plantarum HY7714 clearly inhibited the number, depth, and area of wrinkles in hairless mouse skin. Histological data showed that L. plantarum HY7714 significantly inhibited UVB-induced epidermal thickness in mice. Western blot and zymography data also revealed that L. plantarum HY7714 effectively inhibited MMP-13 expression as well as MMP-2 and -9 activities in dermal tissue. Collectively, these results provide further insight regarding the skin biological actions of L. plantarum HY7714, a potential skin anti-photoaging agent.

DNA Damage and Genomic Instability Induced by Inappropriate DNA Re-replication

DTIC Science & Technology

2007-04-01

Conway, A., Lockhart, D. J., Davis, R. W., Brewer , B. J., and Fangman, W. L. (2001). Replication dynamics of the yeast genome. Science 294, 115–121... Brewer , B. J. (2001). An origin-deficient yeast artificial chromosome triggers a cell cycle checkpoint. Mol. Cell 7, 705–713. Vas, A., Mok, W., and...replication in yeast cells. We have demonstrated that re-replication induces a rapid and significant decrease in cell viability and a cellular DNA damage

Efficient Production of Retroviruses Using PLGA/bPEI-DNA Nanoparticles and Application for Reprogramming Somatic Cells

PubMed Central

Do, Eun Kyoung; Cheon, Hyo Cheon; Heo, Soon Chul; Kwon, Yang Woo; Jeong, Geun Ok; Kim, Ba Reun; Kim, Jae Ho

2013-01-01

Reprogramming of somatic cells to pluripotent cells requires the introduction of factors driving fate switches. Viral delivery has been the most efficient method for generation of induced pluripotent stem cells. Transfection, which precedes virus production, is a commonly-used process for delivery of nucleic acids into cells. The aim of this study is to evaluate the efficiency of PLGA/ bPEI nanoparticles in transfection and virus production. Using a modified method of producing PLGA nanoparticles, PLGA/bPEI-DNA nanoparticles were examined for transfection efficiency and virus production yield in comparison with PLGA-DNA, bPEI-DNA nanoparticles or liposome-DNA complexes. After testing various ratios of PLGA, bPEI, and DNA, the ratio of 6:3:1 (PLGA:bPEI:DNA, w/w/w) was determined to be optimal, with acceptable cellular toxicity. PLGA/bPEI-DNA (6:3:1) nanoparticles showed superior transfection efficiency, especially in multiple gene transfection, and viral yield when compared with liposome-DNA complexes. The culture supernatants of HEK293FT cells transfected with PLGA/bPEI-DNA of viral constructs containing reprogramming factors (Oct4, Sox2, Klf4, or c-Myc) successfully and more efficiently generated induced pluripotent stem cell colonies from mouse embryonic fibroblasts. These results strongly suggest that PLGA/bPEI-DNA nanoparticles can provide significant advantages in studying the effect of multiple factor delivery such as in reprogramming or direct conversion of cell fate. PMID:24098810

Inducible repair of alkylated DNA in microorganisms.

PubMed

Mielecki, Damian; Wrzesiński, Michał; Grzesiuk, Elżbieta

2015-01-01

Alkylating agents, which are widespread in the environment, also occur endogenously as primary and secondary metabolites. Such compounds have intrinsically extremely cytotoxic and frequently mutagenic effects, to which organisms have developed resistance by evolving multiple repair mechanisms to protect cellular DNA. One such defense against alkylation lesions is an inducible Adaptive (Ada) response. In Escherichia coli, the Ada response enhances cell resistance by the biosynthesis of four proteins: Ada, AlkA, AlkB, and AidB. The glycosidic bonds of the most cytotoxic lesion, N3-methyladenine (3meA), together with N3-methylguanine (3meG), O(2)-methylthymine (O(2)-meT), and O(2)-methylcytosine (O(2)-meC), are cleaved by AlkA DNA glycosylase. Lesions such as N1-methyladenine (1meA) and N3-methylcytosine (3meC) are removed from DNA and RNA by AlkB dioxygenase. Cytotoxic and mutagenic O(6)-methylguanine (O(6)meG) is repaired by Ada DNA methyltransferase, which transfers the methyl group onto its own cysteine residue from the methylated oxygen. We review (i) the individual Ada proteins Ada, AlkA, AlkB, AidB, and COG3826, with emphasis on the ubiquitous and versatile AlkB and its prokaryotic and eukaryotic homologs; (ii) the organization of the Ada regulon in several bacterial species; (iii) the mechanisms underlying activation of Ada transcription. In vivo and in silico analysis of various microorganisms shows the widespread existence and versatile organization of Ada regulon genes, including not only ada, alkA, alkB, and aidB but also COG3826, alkD, and other genes whose roles in repair of alkylated DNA remain to be elucidated. This review explores the comparative organization of Ada response and protein functions among bacterial species beyond the classical E. coli model. Copyright © 2014 Elsevier B.V. All rights reserved.

Far-ultraviolet spectral changes of titanium dioxide with gold nanoparticles by ultraviolet and visible light.

PubMed

Tanabe, Ichiro; Kurawaki, Yuji

2018-05-15

Attenuated total reflectance spectra including the far-ultraviolet (FUV, ≤200nm) region of titanium dioxide (TiO 2 ) with and without gold (Au) nanoparticles were measured. A newly developed external light-irradiation system enabled to observe spectral changes of TiO 2 with Au nanoparticles upon light irradiations. Absorption in the FUV region decreased and increased by the irradiation with ultraviolet and visible light, respectively. These spectral changes may reflect photo-induced electron transfer from TiO 2 to Au nanoparticles under ultraviolet light and from Au nanoparticles to TiO 2 under visible light, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Altered DNA Methylation and Expression Profiles of 8-Oxoguanine DNA Glycosylase 1 in Lens Tissue from Age-related Cataract Patients.

PubMed

Wang, Yong; Li, Fei; Zhang, Guowei; Kang, Lihua; Qin, Bai; Guan, Huaijin

2015-01-01

Oxidative stress and DNA damage contribute to the pathogenesis of age-related cataract (ARC). Most oxidative DNA lesions are repaired via the base excision repair (BER) proteins including 8-oxoguanine DNA glycosylase 1 (OGG1). This study examined DNA methylation of CpG islands upstream of OGG1 and their relation to the gene expression in lens cortex from ARC patients. The clinical case-control study consisted of 15 cortical type of ARC patients and 15 age-matched non-ARC controls who received transparent lens extraction due to vitreoretinal diseases. OGG1 expression in lens cortex was analyzed by qRT-PCR and Western blot. The localization and the proportion of cells positive for OGG1 were determined by immunofluorescence. Bisulfite-sequencing PCR (BSP) was performed to evaluate the methylation status of CpG islands near OGG1 in DNA extracted from lens cortex. To test relationship between the methylation and the expression of the gene of interest, 5-Aza-2'-deoxycytidine (5-Aza-dC) was used to induce demethylation of cultured human lens epithelium B-3 (HLE B-3). To test the role of OGG1 in the repair of cellular damage, HLE B-3 was transfected with OGG1 vector, followed by ultraviolet radiation b (UVB) exposure to induce apoptosis. The mRNA and protein levels of OGG1 were significantly reduced in the lens cortex of ARC. Immunofluorescence showed that the proportion of OGG1-positive cells decreased significantly in ARC cortex in comparison with the control. The CpG island in first exon of OGG1 displayed hypermethylation in the DNA extracted from the lens cortex of ARC. Treatment of HLEB-3 cells with 5-Aza-dC upregulated OGG1 expression. UVB-induced apoptosis was attenuated after transfection with OGG1. A reduced OGG1 expression was correlated with hypermethylation of a CpG island of OGG1 in lens cortex of ARC. The role of epigenetic change in OGG1 gene in the susceptibility to oxidative stress induced cortical ARC is warranted to further study.

Linking JNK Activity to the DNA Damage Response

PubMed Central

Picco, Vincent

2013-01-01

The activity of c-Jun N-terminal kinase (JNK) was initially described as ultraviolet- and oncogene-induced kinase activity on c-Jun. Shortly after this initial discovery, JNK activation was reported for a wider variety of DNA-damaging agents, including γ-irradiation and chemotherapeutic compounds. As the DNA damage response mechanisms were progressively uncovered, the mechanisms governing the activation of JNK upon genotoxic stresses became better understood. In particular, a recent set of papers links the physical breakage in DNA, the activation of the transcription factor NF-κB, the secretion of TNF-α, and an autocrine activation of the JNK pathway. In this review, we will focus on the pathway that is initiated by a physical break in the DNA helix, leading to JNK activation and the resultant cellular consequences. The implications of these findings will be discussed in the context of cancer therapy with DNA-damaging agents. PMID:24349633

An extended sequence specificity for UV-induced DNA damage.

PubMed

Chung, Long H; Murray, Vincent

2018-01-01

The sequence specificity of UV-induced DNA damage was determined with a higher precision and accuracy than previously reported. UV light induces two major damage adducts: cyclobutane pyrimidine dimers (CPDs) and pyrimidine(6-4)pyrimidone photoproducts (6-4PPs). Employing capillary electrophoresis with laser-induced fluorescence and taking advantages of the distinct properties of the CPDs and 6-4PPs, we studied the sequence specificity of UV-induced DNA damage in a purified DNA sequence using two approaches: end-labelling and a polymerase stop/linear amplification assay. A mitochondrial DNA sequence that contained a random nucleotide composition was employed as the target DNA sequence. With previous methodology, the UV sequence specificity was determined at a dinucleotide or trinucleotide level; however, in this paper, we have extended the UV sequence specificity to a hexanucleotide level. With the end-labelling technique (for 6-4PPs), the consensus sequence was found to be 5'-GCTC*AC (where C* is the breakage site); while with the linear amplification procedure, it was 5'-TCTT*AC. With end-labelling, the dinucleotide frequency of occurrence was highest for 5'-TC*, 5'-TT* and 5'-CC*; whereas it was 5'-TT* for linear amplification. The influence of neighbouring nucleotides on the degree of UV-induced DNA damage was also examined. The core sequences consisted of pyrimidine nucleotides 5'-CTC* and 5'-CTT* while an A at position "1" and C at position "2" enhanced UV-induced DNA damage. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Toll-Like Receptor-4 deficiency enhances repair of ultraviolet radiation induced cutaneous DNA damage by nucleotide excision repair mechanism

PubMed Central

Ahmad, Israr; Simanyi, Eva; Guroji, Purushotham; Tamimi, Iman A; delaRosa, Hillary J; Nagar, Anusuiya; Nagar, Priyamvada; Katiyar, Santosh K; Elmets, Craig A; Yusuf, Nabiha

2014-01-01

UVB-induced DNA damage plays a critical role in development of photoimmunosuppression. The purpose of this study was to determine whether repair of UVB-induced DNA damage is regulated by Toll-like receptor-4 (TLR4). When TLR4 gene knockout (TLR4-/-) and TLR4 competent (TLR4+/+) mice were subjected to 90 mJ/cm2 UVB radiation locally, DNA damage in the form of CPD, were repaired more efficiently in the skin and bone marrow dendritic cells (BMDC) of TLR4-/- mice in comparison to TLR4+/+ mice. Expression of DNA repair gene XPA (Xeroderma pigmentosum complementation group A) was significantly lower in skin and BMDC of TLR4+/+ mice than TLR4-/- mice after UVB exposure. When cytokine levels were compared in these strains after UVB exposure, BMDC from UV-irradiated TLR4-/- mice produced significantly more interleukin (IL)-12 and IL-23 cytokines (p<0.05) than BMDC from TLR4+/+ mice. Addition of anti-IL-12 and anti-IL-23 antibodies to BMDC of TLR4-/- mice (before UVB exposure) inhibited repair of CPD, with a concomitant decrease in XPA expression. Addition of TLR4 agonist to TLR4+/+ BMDC cultures decreased XPA expression and inhibited CPD repair. Thus, strategies to inhibit TLR4 may allow for immunopreventive and immunotherapeutic approaches for managing UVB-induced cutaneous DNA damage and skin cancer. PMID:24326454

Protective Effect of Mangifera indica Linn., Cocos nucifera Linn., and Averrhoa carambola Linn. Extracts against Ultraviolet B-Induced Damage in Human Keratinocytes

PubMed Central

Ronpirin, Chalinee; Pattarachotanant, Nattaporn

2016-01-01

This study was aimed at investigating the antioxidant activity of Mangifera indica Linn., Cocos nucifera Linn., and Averrhoa carambola Linn. and their biological effect on human keratinocytes affected by the ultraviolet B (UVB), a major cause of cell damage and skin cancer through induction of DNA damage, production of reactive oxygen species (ROS), and apoptosis. The richest antioxidant activity was found in ethanol fraction of M. indica (21.32 ± 0.66 mg QE/g dry weight), while the lowest one was found in aqueous fractions of M. indica and C. nucifera (1.76 ± 2.10 and 1.65 ± 0.38 mg QE/g dry weight, respectively). Ethanol and aqueous fractions of A. carambola (250 µg/mL) significantly reduced the number of apoptotic cells. The expression of cleaved caspase 3 in UVB-treated group was significantly greater than that in untreated group. Both fractions of A. carambola (50, 100, and 250 µg/mL) significantly decreased the expression of cleaved caspase 3. Regarding the induction of DNA repair, ethanol (100 and 250 µg/mL) and aqueous (50, 100 and 250 µg/mL) fractions of A. carambola significantly decreased the percentage of cyclobutane pyrimidine dimers (CPD). Taken together, our results suggest that both fractions of A. carambola may be potentially developed for dermal applications. PMID:27057195

Protective Effect of Mangifera indica Linn., Cocos nucifera Linn., and Averrhoa carambola Linn. Extracts against Ultraviolet B-Induced Damage in Human Keratinocytes.

PubMed

Ronpirin, Chalinee; Pattarachotanant, Nattaporn; Tencomnao, Tewin

2016-01-01

This study was aimed at investigating the antioxidant activity of Mangifera indica Linn., Cocos nucifera Linn., and Averrhoa carambola Linn. and their biological effect on human keratinocytes affected by the ultraviolet B (UVB), a major cause of cell damage and skin cancer through induction of DNA damage, production of reactive oxygen species (ROS), and apoptosis. The richest antioxidant activity was found in ethanol fraction of M. indica (21.32 ± 0.66 mg QE/g dry weight), while the lowest one was found in aqueous fractions of M. indica and C. nucifera (1.76 ± 2.10 and 1.65 ± 0.38 mg QE/g dry weight, respectively). Ethanol and aqueous fractions of A. carambola (250 µg/mL) significantly reduced the number of apoptotic cells. The expression of cleaved caspase 3 in UVB-treated group was significantly greater than that in untreated group. Both fractions of A. carambola (50, 100, and 250 µg/mL) significantly decreased the expression of cleaved caspase 3. Regarding the induction of DNA repair, ethanol (100 and 250 µg/mL) and aqueous (50, 100 and 250 µg/mL) fractions of A. carambola significantly decreased the percentage of cyclobutane pyrimidine dimers (CPD). Taken together, our results suggest that both fractions of A. carambola may be potentially developed for dermal applications.

Tangeretin reduces ultraviolet B (UVB)-induced cyclooxygenase-2 expression in mouse epidermal cells by blocking mitogen-activated protein kinase (MAPK) activation and reactive oxygen species (ROS) generation.

PubMed

Yoon, Ji Hye; Lim, Tae-Gyu; Lee, Kyung Mi; Jeon, Ae Ji; Kim, Su Yeon; Lee, Ki Won

2011-01-12

The present study examined the effects of tangeretin, a polymethoxylated flavonone present in citrus fruits, on ultraviolet B (UVB)-induced cyclooxygenase-2 (COX-2) expression in JB6 P+ mouse skin epidermal cells. Tangeretin suppressed UVB-induced COX-2 expression and transactivation of nuclear factor-κB and activator protein-1 in JB6 P+ cells. Moreover, tangeretin blocked UVB-induced phosphorylation of Akt and mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated protein kinase, c-Jun N-terminal kinase, and p38, and attenuated the phosphorylation of MAPK kinases 1/2, 3/6, and 4. Tangeretin also limited the endogenous generation of reactive oxygen species (ROS), thereby protecting the cells against oxidative stress. However, tangeretin did not scavenge the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and influence the nicotinamide adenine dinucleotide phosphate oxidase activity. These results suggest that the anti-inflammatory effects of tangeretin stem from its modulation of cell signaling and suppression of intracellular ROS generation. Tangeretin may have a potent chemopreventive effect in skin cancer.

Nbs1 ChIP-Seq Identifies Off-Target DNA Double-Strand Breaks Induced by AID in Activated Splenic B Cells

PubMed Central

Linehan, Erin K.; Schrader, Carol E.; Stavnezer, Janet

2015-01-01

Activation-induced cytidine deaminase (AID) is required for initiation of Ig class switch recombination (CSR) and somatic hypermutation (SHM) of antibody genes during immune responses. AID has also been shown to induce chromosomal translocations, mutations, and DNA double-strand breaks (DSBs) involving non-Ig genes in activated B cells. To determine what makes a DNA site a target for AID-induced DSBs, we identify off-target DSBs induced by AID by performing chromatin immunoprecipitation (ChIP) for Nbs1, a protein that binds DSBs, followed by deep sequencing (ChIP-Seq). We detect and characterize hundreds of off-target AID-dependent DSBs. Two types of tandem repeats are highly enriched within the Nbs1-binding sites: long CA repeats, which can form Z-DNA, and tandem pentamers containing the AID target hotspot WGCW. These tandem repeats are not nearly as enriched at AID-independent DSBs, which we also identified. Msh2, a component of the mismatch repair pathway and important for genome stability, increases off-target DSBs, similar to its effect on Ig switch region DSBs, which are required intermediates during CSR. Most of the off-target DSBs are two-ended, consistent with generation during G1 phase, similar to DSBs in Ig switch regions. However, a minority are one-ended, presumably due to conversion of single-strand breaks to DSBs during replication. One-ended DSBs are repaired by processes involving homologous recombination, including break-induced replication repair, which can lead to genome instability. Off-target DSBs, especially those present during S phase, can lead to chromosomal translocations, deletions and gene amplifications, resulting in the high frequency of B cell lymphomas derived from cells that express or have expressed AID. PMID:26263206

[Decrease of spontaneous mutations in Haemophilus influenzae caused by transformation with its own DNA irradiated with near-ultraviolet light].

PubMed

Alarcón-Hernández, E; Cabrera-Juárez, E

1992-01-01

Transforming DNA containing the streptomycin resistance marker, was irradiated for 8 h with broad near ultraviolet light (325-400 nm) at pH 4.8, and the inactivation kinetics determined. After selection of streptomycin resistant transformants, they were grown until a turbidity of 150-200 Klett units. In these cultures we looked for new markers coming from the irradiated transforming DNA. We looked and found the novobiocin resistance marker and one that conveys to protoporphyrin IX utilization, measured as an increase in the mutation frequency of these markers in the streptomycin resistant population. In other experiments, we found a decline in spontaneous mutation frequency for the same markers in the cells transformed with irradiated DNA. This last finding rises the possibility of alterations on the mutator genes as a result of near ultraviolet irradiation.

Computational Approach to Explore the B/A Junction Free Energy in DNA.

PubMed

Kulkarni, Mandar; Mukherjee, Arnab

2016-01-04

Protein-DNA interactions induce conformational changes in DNA such as B- to A-form transitions at a local level. Such transitions are associated with a junction free energy cost at the boundary of two different conformations in a DNA molecule. In this study, we performed umbrella sampling simulations to find the free energy values of the B-A transition at the dinucleotide and trinucleotide level of DNA. Using a combination of dinucleotide and trinucleotide free energy costs obtained from simulations, we calculated the B/A junction free energy. Our study shows that the B/A junction free energy is 0.52 kcal mol(-1) for the A-philic GG step and 1.59 kcal mol(-1) for the B-philic AA step. This observation is in agreement with experimentally derived values. After excluding junction effects, we obtained an absolute free energy cost for the B- to A-form conversion for all the dinucleotide steps. These absolute free energies may be used for predicting the propensity of structural transitions in DNA. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Overstretching of B-DNA with various pulling protocols: Appearance of structural polymorphism and S-DNA

NASA Astrophysics Data System (ADS)

Garai, Ashok; Mogurampelly, Santosh; Bag, Saientan; Maiti, Prabal K.

2017-12-01

We report a structural polymorphism of the S-DNA when a canonical B-DNA is stretched under different pulling protocols and provide a fundamental molecular understanding of the DNA stretching mechanism. Extensive all atom molecular dynamics simulations reveal a clear formation of S-DNA when the B-DNA is stretched along the 3' directions of the opposite strands (OS3) and is characterized by the changes in the number of H-bonds, entropy, and free energy. Stretching along the 5' directions of the opposite strands (OS5) leads to force induced melting form of the DNA. Interestingly, stretching along the opposite ends of the same strand leads to a coexistence of both the S- and melted M-DNA structures. We also do the structural characterization of the S-DNA by calculating various helical parameters. We find that the S-DNA has a twist of ˜10° which corresponds to a helical repeat length of ˜36 base pairs in close agreement with the previous experimental results. Moreover, we find that the free energy barrier between the canonical and overstretched states of DNA is higher for the same termini pulling protocol in comparison to all other protocols considered in this work. Overall, our observations not only reconcile with the available experimental results qualitatively but also enhance the understanding of different overstretched DNA structures.

Ultrastructure study of hair damage after ultraviolet irradiation.

PubMed

Zuel-Fakkar, Nehal Mohamed; El Khateeb, Ekramy Ahmed; Cousha, Hala Sobhi; Hamed, Dina Mohamed

2013-12-01

Natural ultraviolet exposure induces hair damage, which is difficult to avoid. Most of the research work is focused on the effect of ultraviolet on the epidermis, dermis as well as the immune system, whereas the long-term effect of ultraviolet on hair has not been investigated. we performed our experiment to find out the changes induced in hair follicle and shaft in those patients exposed to high doses of ultraviolet (A and B) during treatment of other skin conditions. Light and transmission electron microscopy examination of scalp hair follicles and shafts of 10 patients with vitiligo under psoralen plus ultraviolet A (group 1) and 10 patients with vitiligo under narrow band ultraviolet B (group 2) was carried out and compared with those of 10 healthy volunteers (group 3). Physical changes in the appearance of hair were more in groups 1 and 2 than control. Reduced hair follicle thickness and perifollicular infiltrate and hyaline disorganized perifollicular collagen were observed more in group 1 than in group 2 with the absence of these changes in group 3. Transmission electron microscopy showed nonspecific cell injury in hair follicles in group 1 more than the other 2 groups, while the damaging effect on hair was more in the second group than the others. Due to the damaging effect of ultraviolet on hair, patients under treatment with this modality should be cautious to protect their hair during treatment. © 2013 Wiley Periodicals, Inc.

Hypersensitivity of skin fibroblasts from basal cell nevus syndrome patients to killing by ultraviolet B but not by ultraviolet C radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Applegate, L.A.; Goldberg, L.H.; Ley, R.D.

Basal cell nevus syndrome (BCNS) is an autosomal dominant genetic disorder in which the afflicted individuals are extremely susceptible to sunlight-induced skin cancers, particularly basal cell carcinomas. However, the cellular and molecular basis for BCNS is unknown. To ascertain whether there is any relationship between genetic predisposition to skin cancer and increased sensitivity of somatic cells from BCNS patients to killing by UV radiation, we exposed skin fibroblasts established from unexposed skin biopsies of several BCNS and age- and sex-matched normal individuals to either UV-B (280-320 nm) or UV-C (254 nm) radiation and determined their survival. The results indicated thatmore » skin fibroblasts from BCNS patients were hypersensitive to killing by UV-B but not UV-C radiation as compared to skin fibroblasts from normal individuals. DNA repair studies indicated that the increased sensitivity of BCNS skin fibroblasts to killing by UV-B radiation was not due to a defect in the excision repair of pyrimidine dimers. These results indicate that there is an association between hypersensitivity of somatic cells to killing by UV-B radiation and the genetic predisposition to skin cancer in BCNS patients. In addition, these results suggest that DNA lesions (and repair processes) other than the pyrimidine dimer are also involved in the pathogenesis of sunlight-induced skin cancers in BCNS patients. More important, the UV-B sensitivity assay described here may be used as a diagnostic tool to identify presymptomatic individuals with BCNS.« less

Purification and characterization of an endonuclease from calf thymus acting on irradiated DNA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bacchetti, S.; Benne, R.

1974-01-01

An endonuclease acting on DNA exposed to ultraviolet light or gamma-rays was extensively purified from calf thymus. The enzyme has a pH optimum at pH 7.0 to 7.5, acts with equal efficiency in the presence of EDTA or divalent cations (Mg 2+ or Ca 2+), is inhibited by NaC1 and tRNA and is inactivated by incubation at 50 C. Its molecular weight, determined by Sephadex chromatography or SDS-gel electrophoresis, is + or - 30,000. The enzyme catalyzes the formation of single-strand breaks with 5'-phosphate termini in double-stranded DNA irradiated with ultraviolet or gamma-rays. It does not act on unirradiated DNAmore » or denatured DNA. The enzymatic activity on ultraviolet- and gamma-irradiated DNA is associated with the same protein. The site of action of the enzyme in ultraviolet-irradiated DNA is a photoproduct other than pyrimidine dimers, and can also be induced by irradiation of the DNA in vivo. (Author) (GRA)« less

Inhibition of ultraviolet light-induced oxidative events in the skin and internal organs of hairless mice by isoflavone genistein.

PubMed

Wei, Huachen; Zhang, Xueshu; Wang, Yan; Lebwohl, Mark

2002-11-08

We have previously demonstrated that soybean isoflavone genistein inhibits ultraviolet-B (UVB)-induced skin tumorigenesis in hairless mice. In the present study, we further investigated the possible mechanism(s) of action whereby genistein inhibits photocarcinogenesis with focuses on UVB-induced oxidative events, including hydrogen peroxide (H(2)O(2)) production, lipid peroxidation (as represented by malondialdehyde, MDA), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation in vivo. We demonstrated that subacute exposure to UVB substantially increased the level of H(2)O(2), lipid peroxides, and 8-OHdG in skin of hairless mice. In addition, chronic exposure to low-dose UVB (0.9-1.2 kJ/m(2) for 20 weeks) substantially increased the levels of 8-OHdG not only in the epidermis, but also in the internal organs such as liver, brain, and spleen of mice with exception of kidney. However, genistein did not affect the level of UVB-induced pyrimidine dimmers in the same UVB exposed mouse skin, indicating selective inhibition of oxidative DNA damage by genistein. Induction of H(2)O(2) was independent of UVB fluences whereas the levels of MDA and 8-OHdG were induced in an UVB fluence-dependent manner. The results suggest that H(2)O(2) be generated as an acute cutaneous response to UVB irradiation, while MDA and 8-OHdG are accumulated with increasing UVB exposure and more closely related to chronic effects of UVB radiation. Pre-treatment of animals with 10 micromol of genistein 1 h prior to UVB exposure significantly inhibited UVB-induced H(2)O(2) and MDA in skin and 8-OHdG in epidermis as well as internal organs. Suppression of 8-OHdG formation by genistein has been corroborated in purified DNA irradiated with UVA and B. In summary, our results suggest that UVB irradiation elicit a series of oxidative events, which can be substantially inhibited by isoflavonoid genistein through either direct quenching of reactive oxygen species or indirect antiinflammatory effects. Thus, the

Ultraviolet-B radiation induced cross-linking improves physical properties of cold- and warm-water fish gelatin gels and films.

PubMed

Otoni, Caio G; Avena-Bustillos, Roberto J; Chiou, Bor-Sen; Bilbao-Sainz, Cristina; Bechtel, Peter J; McHugh, Tara H

2012-09-01

Cold- and warm-water fish gelatin granules were exposed to ultraviolet-B radiation for doses up to 29.7 J/cm(2). Solutions and films were prepared from the granules. Gel electrophoresis and refractive index were used to examine changes in molecular weight of the samples. Also, the gel strength and rheological properties of the solutions as well as the tensile and water vapor barrier properties of the films were characterized. SDS-PAGE and refractive index results indicated cross-linking of gelatin chains after exposure to radiation. Interestingly, UV-B treated samples displayed higher gel strengths, with cold- and warm-water fish gelatin having gel strength increases from 1.39 to 2.11 N and from 7.15 to 8.34 N, respectively. In addition, both gelatin samples exhibited an increase in viscosity for higher UV doses. For gelatin films, the cold-water fish gelatin samples made from irradiated granules showed greater tensile strength. In comparison, the warm-water gelatin films made from irradiated granules had lower tensile strength, but better water vapor barrier properties. This might be due to the UV induced cross-linking in warm-water gelatin that disrupted helical structures. Journal of Food Science copy; 2012 Institute of Food Technologists® No claim to original US government works.

EPA attenuates ultraviolet radiation-induced downregulation of aquaporin-3 in human keratinocytes.

PubMed

Jeon, Byoung-Kook; Kang, Moon-Kyung; Lee, Ghang-Tai; Lee, Kun-Kuk; Lee, Ho-Sub; Woo, Won-Hong; Mun, Yeun-Ja

2015-08-01

Eicosapentaenoic acid (EPA) is an omega-3 polyunsaturated fatty acid (ω-3 PUFA) that protects against photodamage and photocarcinogenesis in mammals. Aquaporin-3 (AQP3) is a water/glycerol transport protein that is found in basal layer keratinocytes. In this study, we have investigated the protective effect of EPA against ultraviolet B (UVB)-induced AQP3 downregulation in human keratinocytes. EPA treatment was found to increase AQP3 gene and protein expression in human epidermal keratinocytes (HaCaT). Using a specific inhibitor, we observed that the effect of EPA on AQP3 expression was mediated by extracellular signal-regulated kinase (ERK) activation. UVB radiation induced AQP3 downregulation in HaCaT cells, and it was found that EPA treatment attenuated UVB-induced AQP3 reduction and the associated cell death. UVB-induced downregulation of AQP3 was blocked by EPA and p38 inhibitor SB203580. Collectively, the present results show that EPA increased AQP3 expression and that this led to a reduction UVB-induced photodamage.

Royal jelly protects against ultraviolet B-induced photoaging in human skin fibroblasts via enhancing collagen production.

PubMed

Park, Hye Min; Hwang, Eunson; Lee, Kwang Gill; Han, Sang-Mi; Cho, Yunhi; Kim, Sun Yeou

2011-09-01

Royal jelly (RJ) is a honeybee product containing proteins, carbohydrates, fats, free amino acids, vitamins, and minerals. As its principal unsaturated fatty acid, RJ contains 10-hydroxy-2-decenoic acid (10-HDA), which may have antitumor and antibacterial activity and a capacity to stimulate collagen production. RJ has attracted interest in various parts of the world for its pharmacological properties. However, the effects of RJ on ultraviolet (UV)-induced photoaging of the skin have not been reported. In this study we measured the 10-HDA content of RJ by high-performance liquid chromatography and tested the effects of RJ on UVB-induced skin photoaging in normal human dermal fibroblasts. The effects of RJ and 10-HDA on UVB-induced photoaging were tested by measuring procollagen type I, transforming growth factor (TGF)-β1, and matrix metalloproteinase (MMP)-1 after UVB irradiation. The RJ contained about 0.211% 10-HDA. The UVB-irradiated human skin fibroblasts treated with RJ and 10-HDA had increased procollagen type I and TGF-β1 productions, but the level of MMP-1 was not changed. Thus RJ may potentially protect the skin from UVB-induced photoaging by enhancing collagen production.

Ultraviolet B-Sensitive Rice Cultivar Deficient in Cyclobutyl Pyrimidine Dimer Repair.

PubMed Central

Hidema, J.; Kumagai, T.; Sutherland, J. C.; Sutherland, B. M.

1997-01-01

Repair of cyclobutyl pyrimidine dimers (CPDs) in DNA is essential in most organisms to prevent biological damage by ultraviolet (UV) light. In higher plants tested thus far, UV-sensitive strains had higher initial damage levels or deficient repair of nondimer DNA lesions but normal CPD repair. This suggested that CPDs might not be important for biological lesions. The photosynthetic apparatus has also been proposed as a critical target. We have analyzed CPD induction and repair in the UV-sensitive rice (Oryza sativa L.) cultivar Norin 1 and its close relative UV-resistant Sasanishiki using alkaline agarose gel electrophoresis. Norin 1 is deficient in cyclobutyl pyrimidine dimer photoreactivation and excision; thus, UV sensitivity correlates with deficient dimer repair. PMID:12223592

EGb-761 prevents ultraviolet B-induced photoaging via inactivation of mitogen-activated protein kinases and proinflammatory cytokine expression.

PubMed

Chen, Chih-Chiang; Chiang, An-Na; Liu, Han-Nan; Chang, Yun-Ting

2014-07-01

EGb-761 is an antioxidant and anticarcinogen; however, its role as a photoprotector remains unknown. To determine whether EGb-761 photoprotects human dermal fibroblasts and BALB/c mice skin against ultraviolet B (UVB) light irradiation. To simulate chronic photodamage, shaved BALB/c mice were exposed to UVB irradiation (90mJ/cm(2)) thrice weekly for 3 months. EGb-761 (2mg/cm(2)) was topically applied 1h before irradiation to evaluate its effect. The mechanisms by which EGb-761 protects the skin from photodamage were evaluated by immunohistochemical analysis, enzyme-linked immunosorbent assay (ELISA), and Western blotting. In BALB/c mice, the signs of photoaging or photodamage, such as coarse wrinkle formation, epidermal hyperplasia, and elastic fiber degeneration, markedly reduced with the topical application of EGb-761. Western blot and ELISA revealed that the activation of MMP-1 in cultured fibroblasts markedly diminished after pretreatment with EGb-761. In addition, EGb-761 inhibited UVB-induced overexpression by the fibroblasts of the proinflammatory cytokines, such as interleukin (IL)-1α, IL-1β, IL-6, and tumor necrosis factor-α. The phosphorylation of the mitogen-activated protein kinase (MAPK) signal transduction pathway components, including extracellular signal-regulated kinase, C-Jun N-terminal kinase, and p38, which are induced by UV irradiation, was significantly inhibited in vivo and in vitro. EGb-761 also diminished the generation of UVB-induced reactive oxygen species (ROS). EGb-761 photoprotects mice and cultured fibroblasts, inhibits the UVB-induced phosphorylation of MAPK pathway components, and reduces the expression of the proinflammatory cytokines by suppressing ROS generation. Thus, topically applied EGb-761 may be a promising photoprotective agent. Copyright © 2014 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

DNA double-strand breaks and Aurora B mislocalization induced by exposure of early mitotic cells to H2O2 appear to increase chromatin bridges and resultant cytokinesis failure.

PubMed

Cho, Min-Guk; Ahn, Ju-Hyun; Choi, Hee-Song; Lee, Jae-Ho

2017-07-01

Aneuploidy, an abnormal number of chromosomes that is a hallmark of cancer cells, can arise from tetraploid/binucleated cells through a failure of cytokinesis. Reactive oxygen species (ROS) have been implicated in various diseases, including cancer. However, the nature and role of ROS in cytokinesis progression and related mechanisms has not been clearly elucidated. Here, using time-lapse analysis of asynchronously growing cells and immunocytochemical analyses of synchronized cells, we found that hydrogen peroxide (H 2 O 2 ) treatment at early mitosis (primarily prometaphase) significantly induced cytokinesis failure. Cytokinesis failure and the resultant formation of binucleated cells containing nucleoplasmic bridges (NPBs) seemed to be caused by increases in DNA double-strand breaks (DSBs) and subsequent unresolved chromatin bridges. We further found that H 2 O 2 induced mislocalization of Aurora B during mitosis. All of these effects were attenuated by pretreatment with N-acetyl-L-cysteine (NAC) or overexpression of Catalase. Surprisingly, the PARP inhibitor PJ34 also reduced H 2 O 2 -induced Aurora B mislocalization and binucleated cell formation. Results of parallel experiments with etoposide, a topoisomerase IIα inhibitor that triggers DNA DSBs, suggested that both DNA DSBs and Aurora B mislocalization contribute to chromatin bridge formation. Aurora B mislocalization also appeared to weaken the "abscission checkpoint". Finally, we showed that KRAS-induced binucleated cell formation appeared to be also H 2 O 2 -dependent. In conclusion, we propose that a ROS, mainly H 2 O 2 increases binucleation through unresolved chromatin bridges caused by DNA damage and mislocalization of Aurora B, the latter of which appears to augment the effect of DNA damage on chromatin bridge formation. Copyright © 2017 Elsevier Inc. All rights reserved.

Spectral transmission of the pig lens: effect of ultraviolet A+B radiation.

PubMed

Artigas, C; Navea, A; López-Murcia, M-M; Felipe, A; Desco, C; Artigas, J-M

2014-12-01

To determine the spectral transmission curve of the crystalline lens of the pig. To analyse how this curve changes when the crystalline lens is irradiated with ultraviolet A+B radiation similar to that of the sun. To compare these results with literature data from the human crystalline lens. We used crystalline lenses of the common pig from a slaughterhouse, i.e. genetically similar pigs, fed with the same diet, and slaughtered at six months old. Spectral transmission was measured with a Perkin-Elmer Lambda 35 UV/VIS spectrometer. The lenses were irradiated using an Asahi Spectra Lax-C100 ultraviolet source, which made it possible to select the spectral emission band as well as the intensity and exposure time. The pig lens transmits all the visible spectrum (95%) and lets part of the ultraviolet A through (15%). Exposure to acute UV (A+B) irradiation causes a decrease in its transmission as the intensity or exposure time increases: this decrease is considerable in the UV region. We were able to determine the mean spectral transmission curve of the pig lens. It appears to be similar to that of the human lens in the visible spectrum, but different in the ultraviolet. Pig lens transmission is reduced by UV (A+B) irradiation and its transmission in the UV region can even disappear as the intensity or exposure time increases. An adequate exposure intensity and time of UV (A+B) radiation always causes an anterior subcapsular cataract (ASC). Copyright © 2014. Published by Elsevier Masson SAS.

Roles of PCNA ubiquitination and TLS polymerases κ and η in the bypass of methyl methanesulfonate-induced DNA damage

PubMed Central

Wit, Niek; Buoninfante, Olimpia Alessandra; van den Berk, Paul C.M.; Jansen, Jacob G.; Hogenbirk, Marc A.; de Wind, Niels; Jacobs, Heinz

2015-01-01

Translesion synthesis (TLS) provides a highly conserved mechanism that enables DNA synthesis on a damaged template. TLS is performed by specialized DNA polymerases of which polymerase (Pol) κ is important for the cellular response to DNA damage induced by benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE), ultraviolet (UV) light and the alkylating agent methyl methanesulfonate (MMS). As TLS polymerases are intrinsically error-prone, tight regulation of their activity is required. One level of control is provided by ubiquitination of the homotrimeric DNA clamp PCNA at lysine residue 164 (PCNA-Ub). We here show that Polκ can function independently of PCNA modification and that Polη can function as a backup during TLS of MMS-induced lesions. Compared to cell lines deficient for PCNA modification (PcnaK164R) or Polκ, double mutant cell lines display hypersensitivity to MMS but not to BPDE or UV-C. Double mutant cells also displayed delayed post-replicative TLS, accumulate higher levels of replication stress and delayed S-phase progression. Furthermore, we show that Polη and Polκ are redundant in the DNA damage bypass of MMS-induced DNA damage. Taken together, we provide evidence for PCNA-Ub-independent activation of Polκ and establish Polη as an important backup polymerase in the absence of Polκ in response to MMS-induced DNA damage. PMID:25505145

Stage-dependent teratogenic and lethal effects exerted by ultraviolet B radiation on Rhinella (Bufo) arenarum embryos.

PubMed

Castañaga, Luis A; Asorey, Cynthia M; Sandoval, María T; Pérez-Coll, Cristina S; Argibay, Teresa I; Herkovits, Jorge

2009-02-01

The adverse effects of ultraviolet B radiation from 547.2 to 30,096 J/m2 on morphogenesis, cell differentiation, and lethality of amphibian embryos at six developmental stages were evaluated from 24 up to 168 h postexposure. The ultraviolet B radiation lethal dose 10, 50, and 90 values were obtained for all developmental stages evaluated. The lethal dose 50 values, considered as the dose causing lethality in the 50% of the organisms exposed, in J/m2 at 168 h postexposure, ranged from 2,307 to 18,930; gill circulation and blastula were the most susceptible and resistant stages, respectively. Ultraviolet B radiation caused malformations in all developmental stages but was significantly more teratogenic at the gill circulation and complete operculum stages. Moreover, at the gill circulation stage, even the lowest dose (547.2 J/m2) resulted in malformations to 100% of embryos. The most common malformations were persistent yolk plug, bifid spine, reduced body size, delayed development, asymmetry, microcephaly and anencephaly, tail and body flexures toward the irradiated side, agenesia or partial gill development, abnormal pigment distribution, and hypermotility. The stage-dependent susceptibility to ultraviolet B radiation during amphibian embryogenesis could be explained in the framework of evoecotoxicology, considering ontogenic features as biomarkers of environmental signatures of living forms ancestors during the evolutionary process. The stage-dependent susceptibility to ultraviolet B radiation on Rhinella (Bufo) arenarum embryos for both lethal and teratogenic effects could contribute to a better understanding of the role of the increased ultraviolet B radiation on worldwide amphibian populations decline.

Abnormal ultraviolet mutagenic spectrum in plasmid DNA replicated in cultured fibroblasts from a patient with the skin cancer-prone disease, xeroderma pigmentosum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seetharam, S.; Protic-Sabljic, M.; Seidman, M.M.

1987-12-01

A shuttle vector plasmid, pZ189, was utilized to assess the types of mutations that cells from a patient with xeroderma pigmentosum, complementation group D, introduce into ultraviolet (UV) damaged, replicating DNA. Patients with xeroderma pigmentosum have clinical and cellular UV hypersensitivity, increased frequency of sun-induced skin cancer, and deficient DNA repair. In comparison to UV-treated pZ189 replicated in DNA repair-proficient cells, there were fewer surviving plasmids, a higher frequency of plasmids with mutations, fewer plasmids with two or more mutations in the marker gene, and a new mutagenic hotspot. The major type of base substitution mutation was the G:C tomore » A:T transition with both cell lines. These results, together with similar findings published earlier with cells from a xeroderma pigmentosum patient in complementation group A, suggest that isolated G:C to A:T somatic mutations may be particularly important in generation of human skin cancer by UV radiation.« less

miR-125b targets DNMT3b and mediates p53 DNA methylation involving in the vascular smooth muscle cells proliferation induced by homocysteine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, ChengJian; Zhang, HuiPing; Zhao, Li

MicroRNAs (miRNAs) are short non-coding RNA and play crucial roles in a wide array of biological processes, including cell proliferation, differentiation and apoptosis. Our previous studies found that homocysteine(Hcy) can stimulate the proliferation of vascular smooth muscle cells (VSMCs), however, the underlying mechanisms were not fully elucidated. Here, we found proliferation of VSMCs induced by Hcy was of correspondence to the miR-125b expression reduced both in vitro and in the ApoE knockout mice, the hypermethylation of p53, its decreased expression, and DNA (cytosine-5)-methyltransferase 3b (DNMT3b) up-regulated. And, we found DNMT3b is a target of miR-125b, which was verified by themore » Dual-Luciferase reporter assay and western blotting. Besides, the siRNA interference for DNMT3b significantly decreased the methylation level of p53, which unveiled the causative role of DNMT3b in p53 hypermethylation. miR-125b transfection further confirmed its regulative roles on p53 gene methylation status and the VSMCs proliferation. Our data suggested that a miR-125b-DNMT3b-p53 signal pathway may exist in the VSMCs proliferation induced by Hcy.« less

Avoidance of APOBEC3B-induced mutation by error-free lesion bypass

PubMed Central

Hoopes, James I.; Hughes, Amber L.; Hobson, Lauren A.; Cortez, Luis M.; Brown, Alexander J.

2017-01-01

Abstract APOBEC cytidine deaminases mutate cancer genomes by converting cytidines into uridines within ssDNA during replication. Although uracil DNA glycosylases limit APOBEC-induced mutation, it is unknown if subsequent base excision repair (BER) steps function on replication-associated ssDNA. Hence, we measured APOBEC3B-induced CAN1 mutation frequencies in yeast deficient in BER endonucleases or DNA damage tolerance proteins. Strains lacking Apn1, Apn2, Ntg1, Ntg2 or Rev3 displayed wild-type frequencies of APOBEC3B-induced canavanine resistance (CanR). However, strains without error-free lesion bypass proteins Ubc13, Mms2 and Mph1 displayed respective 4.9-, 2.8- and 7.8-fold higher frequency of APOBEC3B-induced CanR. These results indicate that mutations resulting from APOBEC activity are avoided by deoxyuridine conversion to abasic sites ahead of nascent lagging strand DNA synthesis and subsequent bypass by error-free template switching. We found this mechanism also functions during telomere re-synthesis, but with a diminished requirement for Ubc13. Interestingly, reduction of G to C substitutions in Ubc13-deficient strains uncovered a previously unknown role of Ubc13 in controlling the activity of the translesion synthesis polymerase, Rev1. Our results highlight a novel mechanism for error-free bypass of deoxyuridines generated within ssDNA and suggest that the APOBEC mutation signature observed in cancer genomes may under-represent the genomic damage these enzymes induce. PMID:28334887

Transition between B-DNA and Z-DNA: free energy landscape for the B-Z junction propagation.

PubMed

Lee, Juyong; Kim, Yang-Gyun; Kim, Kyeong Kyu; Seok, Chaok

2010-08-05

Canonical, right-handed B-DNA can be transformed into noncanonical, left-handed Z-DNA in vitro at high salt concentrations or in vivo under physiological conditions. The molecular mechanism of this drastic conformational transition is still unknown despite numerous studies. Inspired by the crystal structure of a B-Z junction and the previous zipper model, we show here, with the aid of molecular dynamics simulations, that a stepwise propagation of a B-Z junction is a highly probable pathway for the B-Z transition. In this paper, the movement of a B-Z junction by a two-base-pair step in a double-strand nonamer, [d(GpCpGpCpGpCpGpCpG)](2), is considered. Targeted molecular dynamics simulations and umbrella sampling for this transition resulted in a transition pathway with a free energy barrier of 13 kcal/mol. This barrier is much more favorable than those obtained from previous atomistic simulations that lead to concerted transitions of the whole strands. The free energy difference between B-DNA and Z-DNA evaluated from our simulation is 0.9 kcal/mol per dinucleotide unit, which is consistent with previous experiments. The current computation thus strongly supports the proposal that the B-Z transition involves a relatively fast extension of B-DNA or Z-DNA by sequential propagation of B-Z junctions once nucleation of junctions is established.

Structure and mechanism of human DNA polymerase [eta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biertümpfel, Christian; Zhao, Ye; Kondo, Yuji

2010-11-03

The variant form of the human syndrome xeroderma pigmentosum (XPV) is caused by a deficiency in DNA polymerase {eta} (Pol{eta}), a DNA polymerase that enables replication through ultraviolet-induced pyrimidine dimers. Here we report high-resolution crystal structures of human Pol{eta} at four consecutive steps during DNA synthesis through cis-syn cyclobutane thymine dimers. Pol{eta} acts like a 'molecular splint' to stabilize damaged DNA in a normal B-form conformation. An enlarged active site accommodates the thymine dimer with excellent stereochemistry for two-metal ion catalysis. Two residues conserved among Pol{eta} orthologues form specific hydrogen bonds with the lesion and the incoming nucleotide to assistmore » translesion synthesis. On the basis of the structures, eight Pol{eta} missense mutations causing XPV can be rationalized as undermining the molecular splint or perturbing the active-site alignment. The structures also provide an insight into the role of Pol{eta} in replicating through D loop and DNA fragile sites.« less

Synthesis of Deoxyribonucleic Acid After Ultraviolet Irradiation of Sensitive and Resistant Haemophilus influenzae

PubMed Central

Modak, Sohan P.; Setlow, Jane K.

1969-01-01

Synthesis of deoxyribonucleic acid (DNA) has been measured as a function of ultraviolet (UV) radiation dose in wild-type and seven UV-sensitive strains of Haemophilus influenzae. At the UV doses used, all strains were able to resume DNA synthesis, even those which are unable to excise pyrimidine dimers from their DNA. These excisionless strains showed longer UV-induced delays in DNA synthesis than all but one of the other strains. The longest delay was shown by DB117, a strain which can excise dimers but which is recombination deficient and unable to rejoin X ray-induced single-strand breaks. All strains showed a progressive decrease in sensitivity as they approached the stationary phase. PMID:5305934

Tranexamic acid suppresses ultraviolet B eye irradiation-induced melanocyte activation by decreasing the levels of prohormone convertase 2 and alpha-melanocyte-stimulating hormone.

PubMed

Hiramoto, Keiichi; Yamate, Yurika; Sugiyama, Daijiro; Takahashi, Yumi; Mafune, Eiichi

2014-12-01

Tranexamic acid (trans-4-aminomethylcyclohexanecarboxylic acid) is a medicinal amino acid used in skin whitening care. This study examined the effects of tranexamic acid on the melanocyte activation of the skin induced by an ultraviolet (UV) B eye irradiation. The eye or ear was locally exposed to UVB at a dose of 1.0 kJ/m(2) using a 20SE sunlamp after covering the remaining body surface with aluminum foil. UVB eye irradiation induced melanocyte activation of the skin, similar to that observed following UVB ear irradiation, which was suppressed by the administration of tranexamic acid treatment. The plasma α-melanocyte-stimulating hormone (α-MSH) content was increased by UVB irradiation of the eye; however, the increase in α-MSH was suppressed by tranexamic acid treatment. In addition, UVB eye irradiation induced the up-regulation of prohormone convertase (PC) 2 in the pituitary gland. Meanwhile, the increase in PC2 induced by UVB eye irradiation was suppressed by tranexamic acid treatment. These results clearly indicate that tranexamic acid decreases the expression of PC2, which cleavages from proopiomelanocortin to α-MSH in the pituitary gland, thereby suppressing melanocyte activation. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Wavelength-dependent ultraviolet induction of cyclobutane pyrimidine dimers in the human cornea.

PubMed

Mallet, Justin D; Rochette, Patrick J

2013-08-01

Exposition to ultraviolet (UV) light is involved in the initiation and the progression of skin cancer. The genotoxicity of UV light is mainly attributed to the induction of cyclobutane pyrimidine dimers (CPDs), the most abundant DNA damage generated by all UV types (UVA, B and C). The human cornea is also exposed to the harmful UV radiations, but no UV-related neoplasm has been reported in this ocular structure. The probability that a specific DNA damage leads to a mutation and eventually to cellular transformation is influenced by its formation frequency. To shed light on the genotoxic effect of sunlight in the human eye, we have analyzed CPD induction in the cornea and the iris following irradiation of ex vivo human eyes with UVA, B or C. The extent of CPD induction was used to establish the penetrance of the different UV types in the human cornea. We show that UVB- and UVC-induced CPDs are concentrated in the corneal epithelium and do not penetrate deeply beyond this corneal layer. On the other hand, UVA wavelengths penetrate deeper and induce CPDs in the entire cornea and in the first layers of the iris. Taken together, our results are undoubtedly an important step towards better understanding the consequences of UV exposure to the human eye.

Effects of the nonsugar fraction of brown sugar on chronic ultraviolet B irradiation-induced photoaging in melanin-possessing hairless mice.

PubMed

Sumiyoshi, Maho; Hayashi, Teruaki; Kimura, Yoshiyuki

2009-04-01

Brown sugar has been used traditionally for the treatment of skin trouble as a component of soaps or lotions. Symptoms of aging including wrinkles and pigmentation develop earlier in sun-exposed skin than unexposed skin, a phenomenon referred to as photoaging. Ultraviolet B (UVB) radiation is one of the most important environmental factors influencing photoaging. The aim of this study was to clarify whether the nonsugar fraction of brown sugar prevents chronic UVB-induced aging of the skin using melanin-possessing hairless mice. The nonsugar fraction (1% or 3% solution, 50 mul/mouse) was applied topically to the dorsal region every day for 19 weeks. Both solutions prevented an increase in skin thickness and reduction in skin elasticity caused by the UVB. The 3% solution also prevented wrinkles and melanin pigmentation as well as increases in the diameter and length of skin blood vessels. Increases in the expression of matrix metalloproteinase-2 (MMP-2) and vascular endothelial growth factor (VEGF) in UVB-irradiated skin was inhibited by the nonsugar fraction. Prevention of UVB-induced aging of the skin by topical application of the nonsugar fraction of brown sugar may be due to inhibition of increases in MMP-2 and VEGF expression.

Protective effect of crocin on ultraviolet B‑induced dermal fibroblast photoaging.

PubMed

Deng, Mingwu; Li, Dong; Zhang, Yichen; Zhou, Guangdong; Liu, Wei; Cao, Yilin; Zhang, Wenjie

2018-06-11

Ultraviolet B (UVB) radiation induces the production of reactive oxygen species (ROS), resulting in the aging of dermal fibroblasts. Crocin, a bioactive constituent of Crocus sativus, possesses anti‑oxidation effects. The purpose of the present study was to evaluate the protective effect of crocin on UVB‑induced dermal fibroblast photoaging. Human dermal fibroblasts were isolated and cultured with different concentrations of crocin prior to and following exposure to UVB irradiation. The senescent phenotypes of cells were evaluated, including cell proliferation, cell cycle, senescence‑associated β‑galactosidase (SA‑β‑gal) expression, intracellular ROS, expression of antioxidant protein glutathione peroxidase 1 (GPX‑1) and extracellular matrix protein collagen type 1 (Col‑1). Crocin rescued the cell proliferation inhibited by UVB irradiation, prevented cell cycle arrest and markedly decreased the number of SA‑β‑gal‑positive cells. In addition, crocin reduced UVB‑induced ROS by increasing GPX‑1 expression and other direct neutralization effects. Furthermore, crocin promoted the expression of the extracellular matrix protein Col‑1. Crocin could effectively prevent UVB‑induced cell damage via the reduction of intracellular ROS; thus, it could potentially be used in the prevention of skin photoaging.

Aflatoxin B1-induced DNA adduct formation and p53 mutations in CYP450-expressing human liver cell lines.

PubMed

Macé, K; Aguilar, F; Wang, J S; Vautravers, P; Gómez-Lechón, M; Gonzalez, F J; Groopman, J; Harris, C C; Pfeifer, A M

1997-07-01

Epidemiological evidence has been supporting a relationship between dietary aflatoxin B1 (AFB1) exposure, development of human primary hepatocellular carcinoma (HCC) and mutations in the p53 tumor suppressor gene. However, the correlation between the observed p53 mutations, the AFB1 DNA adducts and their activation pathways has not been elucidated. Development of relevant cellular in vitro models, taking into account species and tissue specificity, could significantly contribute to the knowledge of cytotoxicity and genotoxicity mechanisms of chemical procarcinogens, such as AFB1, in humans. For this purpose a non-tumorigenic SV40-immortalized human liver epithelial cell line (THLE cells) which retained most of the phase II enzymes, but had markedly reduced phase I activities was used for stable expression of the human CYP1A2, CYP2A6, CYP2B6 and CYP3A4 cDNA. The four genetically engineered cell lines (T5-1A2, T5-2A6, T5-2B6 and T5-3A4) produced high levels of the specific CYP450 proteins and showed comparable or higher catalytic activities related to the CYP450 expression when compared to human hepatocytes. The T5-1A2, T5-2A6, T5-2B6 and T5-3A4 cell lines exhibited a very high sensitivity to the cytotoxic effects of AFB1 and were approximately 125-, 2-, 2- and 15-fold, respectively, more sensitive than the control T5-neo cells, transfected with an expressing vector which does not contain CYP450 cDNA. In the CYP450-expressing cells, nanomolar doses of AFB1-induced DNA adduct formation including AFB1-N7-guanine, -pyrimidyl and -diol adducts. In addition, the T5-1A2 cells showed AFM1-DNA adducts. At similar levels of total DNA adducts, both the T5-1A2 and T5-3A4 cells showed, at codon 249 of the p53 gene, AGG to AGT transversions at a relative frequency of 15x10(-6). In contrast, only the T5-3A4 cells showed CCC to ACC transversion at codon 250 at a high frequency, whereas the second most frequent mutations found in the T5-1A2 cells were C to T transitions at the first

Single-copy gene detection using branched DNA (bDNA) in situ hybridization.

PubMed

Player, A N; Shen, L P; Kenny, D; Antao, V P; Kolberg, J A

2001-05-01

We have developed a branched DNA in situ hybridization (bDNA ISH) method for detection of human papillomavirus (HPV) DNA in whole cells. Using human cervical cancer cell lines with known copies of HPV DNA, we show that the bDNA ISH method is highly sensitive, detecting as few as one or two copies of HPV DNA per cell. By modifying sample pretreatment, viral mRNA or DNA sequences can be detected using the same set of oligonucleotide probes. In experiments performed on mixed populations of cells, the bDNA ISH method is highly specific and can distinguish cells with HPV-16 from cells with HPV-18 DNA. Furthermore, we demonstrate that the bDNA ISH method provides precise localization, yielding positive signals retained within the subcellular compartments in which the target nucleic acid sequences are localized. As an effective and convenient means for nucleic acid detection, the bDNA ISH method is applicable to the detection of cancers and infectious agents. (J Histochem Cytochem 49:603-611, 2001)

Preventing Ultraviolet Light-Induced Damage: The Benefits of Antioxidants

ERIC Educational Resources Information Center

Yip, Cheng-Wai

2007-01-01

Extracts of fruit peels contain antioxidants that protect the bacterium "Escherichia coli" against damage induced by ultraviolet light. Antioxidants neutralise free radicals, thus preventing oxidative damage to cells and deoxyribonucleic acid. A high survival rate of UV-exposed cells was observed when grapefruit or grape peel extract was…

Quantitation of HBV DNA in human serum using a branched DNA (bDNA) signal amplification assay.

PubMed

Hendricks, D A; Stowe, B J; Hoo, B S; Kolberg, J; Irvine, B D; Neuwald, P D; Urdea, M S; Perrillo, R P

1995-11-01

The aim of this study was to establish the performance characteristics of a nonradioisotopic branched DNA (bDNA) signal amplification assay for quantitation of hepatitis B virus (HBV) DNA in human serum. Quantitation was determined from a standard curve and expressed as HBV DNA equivalents/mL (Eq/mL; 285,000 Eq = 1 pg of double stranded HBV DNA). The bDNA assay exhibited a nearly four log dynamic range of quantitation and an analytical detection limit of approximately 100,000 Eq/mL. To ensure a specificity of 99.7%, the quantitation limit was set at 700,000 Eq/mL. The interassay percent coefficient of variance for quantification values ranged from 10% to 15% when performed by novice users with different sets of reagents. Using the bDNA assay, HBV DNA was detected in 94% to 100% of hepatitis B e antigen-positive specimens and 27% to 31% of hepatitis B e antigen-negative specimens from chronic HBV-infected patients. The bDNA assay may be useful as a prognostic and therapy monitoring tool for the management of HBV-infected patients undergoing antiviral treatment.

Roles of PCNA ubiquitination and TLS polymerases κ and η in the bypass of methyl methanesulfonate-induced DNA damage.

PubMed

Wit, Niek; Buoninfante, Olimpia Alessandra; van den Berk, Paul C M; Jansen, Jacob G; Hogenbirk, Marc A; de Wind, Niels; Jacobs, Heinz

2015-01-01

Translesion synthesis (TLS) provides a highly conserved mechanism that enables DNA synthesis on a damaged template. TLS is performed by specialized DNA polymerases of which polymerase (Pol) κ is important for the cellular response to DNA damage induced by benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE), ultraviolet (UV) light and the alkylating agent methyl methanesulfonate (MMS). As TLS polymerases are intrinsically error-prone, tight regulation of their activity is required. One level of control is provided by ubiquitination of the homotrimeric DNA clamp PCNA at lysine residue 164 (PCNA-Ub). We here show that Polκ can function independently of PCNA modification and that Polη can function as a backup during TLS of MMS-induced lesions. Compared to cell lines deficient for PCNA modification (Pcna(K164R)) or Polκ, double mutant cell lines display hypersensitivity to MMS but not to BPDE or UV-C. Double mutant cells also displayed delayed post-replicative TLS, accumulate higher levels of replication stress and delayed S-phase progression. Furthermore, we show that Polη and Polκ are redundant in the DNA damage bypass of MMS-induced DNA damage. Taken together, we provide evidence for PCNA-Ub-independent activation of Polκ and establish Polη as an important backup polymerase in the absence of Polκ in response to MMS-induced DNA damage. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

MECHANISMS OF PLANT RESISTANCE TO INCREASED SOLAR ULTRAVIOLET-B RADIATION

EPA Science Inventory

Since the major conclusions of the project are being disseminated via the scientific literature, the final report consists of a compilation of 11 articles and manuscripts on the effects of ultraviolet-B radiation (UVB) on soybean growth and yield, stress interactions with UVB, an...

UV-B Radiation Induces Root Bending Through the Flavonoid-Mediated Auxin Pathway in Arabidopsis.

PubMed

Wan, Jinpeng; Zhang, Ping; Wang, Ruling; Sun, Liangliang; Wang, Wenying; Zhou, Huakun; Xu, Jin

2018-01-01

Ultraviolet (UV)-B radiation-induced root bending has been reported; however, the underlying mechanisms largely remain unclear. Here, we investigate whether and how auxin and flavonoids are involved in UV-B radiation-induced root bending in Arabidopsis using physiological, pharmacological, and genetic approaches. UV-B radiation modulated the direction of root growth by decreasing IAA biosynthesis and affecting auxin distribution in the root tips, where reduced auxin accumulation and asymmetric auxin distribution were observed. UV-B radiation increased the distribution of auxin on the nonradiated side of the root tips, promoting growth and causing root bending. Further analysis indicated that UV-B induced an asymmetric accumulation of flavonoids; this pathway is involved in modulating the accumulation and asymmetric distribution of auxin in root tips and the subsequent redirection of root growth by altering the distribution of auxin carriers in response to UV-B radiation. Taken together, our results indicate that UV-B radiation-induced root bending occurred through a flavonoid-mediated phototropic response to UV-B radiation.

Ultraviolet radiation induced discharge laser

DOEpatents

Gilson, Verle A.; Schriever, Richard L.; Shearer, James W.

1978-01-01

An ultraviolet radiation source associated with a suitable cathode-anode electrode structure, disposed in a gas-filled cavity of a high pressure pulsed laser, such as a transverse electric atmosphere (TEA) laser, to achieve free electron production in the gas by photoelectric interaction between ultraviolet radiation and the cathode prior to the gas-exciting cathode-to-anode electrical discharge, thereby providing volume ionization of the gas. The ultraviolet radiation is produced by a light source or by a spark discharge.

AtPDCD5 Plays a Role in Programmed Cell Death after UV-B Exposure in Arabidopsis1[OPEN

PubMed Central

Falcone Ferreyra, María Lorena; D’Andrea, Lucio; AbdElgawad, Hamada

2016-01-01

DNA damage responses have evolved to sense and react to DNA damage; the induction of DNA repair mechanisms can lead to genomic restoration or, if the damaged DNA cannot be adequately repaired, to the execution of a cell death program. In this work, we investigated the role of an Arabidopsis (Arabidopsis thaliana) protein, AtPDCD5, which is highly similar to the human PDCD5 protein; it is induced by ultraviolet (UV)-B radiation and participates in programmed cell death in the UV-B DNA damage response. Transgenic plants expressing AtPDCD5 fused to GREEN FLUORESCENT PROTEIN indicate that AtPDCD5 is localized both in the nucleus and the cytosol. By use of pdcd5 mutants, we here demonstrate that these plants have an altered antioxidant metabolism and accumulate higher levels of DNA damage after UV-B exposure, similar to levels in ham1ham2 RNA interference transgenic lines with decreased expression of acetyltransferases from the MYST family. By coimmunoprecipitation and pull-down assays, we provide evidence that AtPDCD5 interacts with HAM proteins, suggesting that both proteins participate in the same pathway of DNA damage responses. Plants overexpressing AtPDCD5 show less DNA damage but more cell death in root tips upon UV-B exposure. Finally, we here show that AtPDCD5 also participates in age-induced programmed cell death. Together, the data presented here demonstrate that AtPDCD5 plays an important role during DNA damage responses induced by UV-B radiation in Arabidopsis and also participates in programmed cell death programs. PMID:26884483

A geometric ultraviolet-B radiation transfer model applied to vegetation canopies

Treesearch

Wei Gao; Richard H. Grant; Gordon M. Heisler; James R. Slusser

2002-01-01

The decrease in stratospheric ozone (O3) has prompted continued efforts to assess the potential damage to plant and animal life due to enhanced levels of solar ultraviolet (UV)-B (280-320 nm) radiation. The objective of this study was to develop and evaluate an analytical model to simulate the UV-B irradiance loading on horizontal below- canopy...

Molecular response of nasal mucosa to therapeutic exposure to broad-band ultraviolet radiation

PubMed Central

Mitchell, David; Paniker, Lakshmi; Sanchez, Guillermo; Bella, Zsolt; Garaczi, Edina; Szell, Marta; Hamid, Qutayba; Kemeny, Lajos; Koreck, Andrea

2010-01-01

Abstract Ultraviolet radiation (UVR) phototherapy is a promising new treatment for inflammatory airway diseases. However, the potential carcinogenic risks associated with this treatment are not well understood. UV-specific DNA photoproducts were used as biomarkers to address this issue. Radioimmunoassay was used to quantify cyclobutane pyrimidine dimers (CPDs) and (6–4) photoproducts in DNA purified from two milieus: nasal mucosa samples from subjects exposed to intranasal phototherapy and human airway (EpiAirway™) and human skin (EpiDerm™) tissue models. Immunohistochemistry was used to detect CPD formation and persistence in human nasal biopsies and human tissue models. In subjects exposed to broadband ultraviolet radiation, DNA damage frequencies were determined prior to as well as immediately after treatment and at increasing times post-treatment. We observed significant levels of DNA damage immediately after treatment and efficient removal of the damage within a few days. No residual damage was observed in human subjects exposed to multiple UVB treatments several weeks after the last treatment. To better understand the molecular response of the nasal epithelium to DNA damage, parallel experiments were conducted in EpiAirway and EpiDerm model systems. Repair rates in these two tissues were very similar and comparable to that observed in human skin. The data suggest that the UV-induced DNA damage response of respiratory epithelia is very similar to that of the human epidermis and that nasal mucosa is able to efficiently repair UVB induced DNA damage. PMID:18671762

Ultraviolet-B radiation and the immune response of rainbow trout: Chapter 18

USGS Publications Warehouse

Fabacher, David L.; Little, Edward E.; Jones, S.B.; DeFabo, E.C.; Webber, L.J.; Stolen, Joanne S.; Fletcher, Thelma C.

1994-01-01

As part of a larger study on global climate change and ozone depletion we are investigating the effects of ultraviolet-B (UVB) radiation on fishes. We conducted a number of experiments to explore the possible effects of UVB radiation on the immune response of juvenile rainbow trout Oncorhynchus mykiss. In one study, the fish developed sunburn and fungal infection on the dorsal skin after exposure to levels of UVB that simulated ambient solar UVB levels observed at mid-latitudes. In a separate study, UVB-exposed rainbow trout with surgically administered dorsal lesions developed fungal infection on the lesions and surrounding skin. Many of these fish subsequently died within a 9 day exposure period. Fish with surgical lesions, but not exposed to UVB radiation, did not develop fungal infection and did not die. In mammals, UVB-induced immunosuppression is thought to occur through the isomerization of urocanic acid or the formation of DNA pyrimidine dimers, or through some interaction between the two. We found a substance that appeared, upon HPLC detection, to be trans-urocanic acid in the skin of UVB-exposed and unexposed rainbow trout. Neurotransmitter stimulation of adrenoceptors may be involved in changes in pigmentation observed in UVB-exposed fishes. We measured adrenoceptors in skin membranes from rainbow trout exposed to UVB and found a decrease in cz2-adrenoceptors compared with fish not exposed to UVB. Results of our study indicate that prolonged exposure of juvenile rainbow trout to mid-latitude levels of solar UVB may play an important role in the initiation of certain disease outbreaks and may decrease survival of fish that have lesions on the dorsal skin.

Inhibition of Ultraviolet B-Induced Expression of the Proinflammatory Cytokines TNF-α and VEGF in the Cornea by Fucoxanthin Treatment in a Rat Model.

PubMed

Chen, Shiu-Jau; Lee, Ching-Ju; Lin, Tzer-Bin; Liu, Hsiang-Jui; Huang, Shuan-Yu; Chen, Jia-Zeng; Tseng, Kuang-Wen

2016-01-07

Ultraviolet B (UVB) irradiation is the most common cause of radiation damage to the eyeball and is a risk factor for human corneal damage. We determined the protective effect of fucoxanthin, which is a carotenoid found in common edible seaweed, on ocular tissues against oxidative UVB-induced corneal injury. The experimental rats were intravenously injected with fucoxanthin at doses of 0.5, 5 mg/kg body weight/day or with a vehicle before UVB irradiation. Lissamine green for corneal surface staining showed that UVB irradiation caused serious damage on the corneal surface, including severe epithelial exfoliation and deteriorated epithelial smoothness. Histopathological lesion examination revealed that levels of proinflammatory cytokines, including tumor necrosis factor-α (TNF-α) and vascular endothelial growth factor (VEGF), significantly increased. However, pretreatment with fucoxanthin inhibited UVB radiation-induced corneal disorders including evident preservation of corneal surface smoothness, downregulation of proinflammatory cytokine expression, and decrease of infiltrated polymorphonuclear leukocytes from UVB-induced damage. Moreover, significant preservation of the epithelial integrity and inhibition of stromal swelling were also observed after UVB irradiation in fucoxanthin-treated groups. Pretreatment with fucoxanthin may protect against UVB radiation-induced corneal disorders by inhibiting expression of proinflammatory factors, TNF-α, and VEGF and by blocking polymorphonuclear leukocyte infiltration.

The repair of low dose UV light-induced damage to human skin DNA in condition of trace amount Mg 2+

NASA Astrophysics Data System (ADS)

Gao, Fang; Guo, Zhouyi; Zheng, Changchun; Wang, Rui; Liu, Zhiming; Meng, Pei; Zhai, Juan

2008-12-01

Ultraviolet light-induced damage to human skin DNA was widely investigated. The primary mechanism of this damage contributed to form cyclobutane pyrimidine dimmers (CPDs). Although the distribution of UV light-induced CPDs within a defined sequence is similar, the damage in cellular environment which shields the nuclear DNA was higher than that in organism in apparent dose. So we use low UVB light as main study agent. Low dose UV-irradiated HDF-a cells (Human Dermal Fibroblasts-adult cells) which is weaker than epidermic cells were cultured with DMEM at different trace amount of Mg2+ (0mmol/L , 0.1mmol/L , 0.2mmol/L, 0.4mmol/L, 0.8mmol/L, 1.2mmol/L) free-serum DMEM and the repair of DNA strands injured were observed. Treat these cells with DNA strand breaks detection, photoproducts detection and the repair of photoproducts detection. Then quantitate the role of trace amount Mg2+ in repair of UV light-induced damage to human skin. The experiment results indicated that epidermic cells have capability of resistance to UV-radiation at a certain extent. And Mg2+ can regulate the UV-induced damage repair and relative vitality. It can offer a rationale and experiment data to relieve UV light-induced skin disease.

Interaction investigations of HipA binding to HipB dimer and HipB dimer + DNA complex: a molecular dynamics simulation study.

PubMed

Li, Chaoqun; Wang, Yaru; Wang, Yan; Chen, Guangju

2013-11-01

We carried out molecular dynamics simulations and free energy calculations for a series of ternary and diplex models for the HipA protein, HipB dimer, and DNA molecule to address the mechanism of HipA sequestration and the binding order of events from apo HipB/HipA to 2HipA + HipB dimer + DNA complex. The results revealed that the combination of DNA with the HipB dimer is energetically favorable for the combination of HipB dimer with HipA protein. The binding of DNA to HipB dimer induces a long-range allosteric communication from the HipB2 -DNA interface to the HipA-HipB2 interface, which involves the closeness of α1 helices of HipB dimer to HipA protein and formations of extra hydrogen bonds in the HipA-HipB2 interface through the extension of α2/3 helices in the HipB dimer. These simulated results suggested that the DNA molecule, as a regulative media, modulates the HipB dimer conformation, consequently increasing the interactions of HipB dimer with the HipA proteins, which explains the mechanism of HipA sequestration reported by the previous experiment. Simultaneously, these simulations also explored that the thermodynamic binding order in a simulated physiological environment, that is, the HipB dimer first bind to DNA to form HipB dimer + DNA complex, then capturing strongly the HipA proteins to form a ternary complex, 2HipA + HipB dimer + DNA, for sequestrating HipA in the nucleoid. Copyright © 2013 John Wiley & Sons, Ltd.

Ultraviolet converter transients induced by electrons

NASA Technical Reports Server (NTRS)

Kernell, R. L.; Becher, J.; Reft, C. S.

1984-01-01

The output of ultraviolet converters typically used in satellite astronomy was monitored during irradiation with electrons from a sealed SR-90 source which approximated the peak flux in earth's outer electron belt. The signal induced by irradiation was attributed to two mechanisms: (1) photoelectrons resulting from photons created in the MgF2 window and (2) the direct impact of electrons on the phosphor. For irradiation at about 1 x 10 to the 7th e/sq cm sec, these two effects produced signals which were, in order of magnitude, the same as those produced by an incident UV flux (254 nm) of 10 to the 8th and 10 to the 7th photons/sq cm sec, respectively. In addition, the induced signal was investigated as a function of electron energy by irradiating another converter with 0.4-1.8-MeV electrons from a Van de Graaff. These results suggest that the dominant contribution to the electron-induced signal is Cerenkov photon production in the MgF2 window.

Changes in ultrastructure and responses of antioxidant systems of algae (Dunaliella salina) during acclimation to enhanced ultraviolet-B radiation.

PubMed

Tian, Jiyuan; Yu, Juan

2009-12-02

Because of depletion of the stratospheric ozone layer, levels of solar ultraviolet-B (UV-B) radiation (280-315 nm), which penetrates the water column to an ecologically-significant depth, are increasing. In order to assess changes in ultrastructure and responses of antioxidant systems of algae during acclimation to enhanced ultraviolet-B radiation, Dunaliella salina was treated with higher dose of UV-B radiation (13.2 kJm(-2) d(-1) dose) in this study. As compared to the control panel (8.8 kJm(-2) d(-1)), the treatment D. salina had many changes in ultrastructures: (1) thylakoids became swelled, and some of them penetrated into the pyrenoid; (2) lipid globules accumulated; (3) the amounts of starch grains increased; (4) cristae of mitochondria disintegrated; (5) inclusions in vacuoles reduced; and (6) cisternae of Golgi dictyosomes became loose and swollen. Enhanced UV-B irradiation also induced different responses of the antioxidant systems in D. salina: (1) contents of TBARS (thiobarbituric acid reacting substance) and H(2)O(2) increased significantly (p<0.05); (2) levels of MAAs (mycosporine-like amino acids) increased at the beginning and subsequently decreased, and finally they leveled off at lower values; (3) there were not apparent variations for carotenoid contents, and contents of chlorophyll a presented a trend of initial increase and ultimate decrease; (4) both ascorbate and glutathione contents increased significantly (p<0.05); and (5) for the enzyme activities, POD activities increased remarkably (p<0.05), and SOD activities declined apparently (p<0.05), and CAT activity in D. salina had slight variations (p>0.05). In addition, growth curve displayed that enhanced UV-B radiation prominently inhibited increase of cell concentration when compared with control panel (p<0.05). Our results indicated that enhanced UV-B radiation caused ultrastructural changes of D. salina and induced different responses of antioxidant systems in D. salina.

Anti-Pigmentation Effects of Eight Phellinus linteus-Fermented Traditional Crude Herbal Extracts on Brown Guinea Pigs of Ultraviolet B-Induced Hyperpigmentation.

PubMed

Ahn, Hee-Young; Choo, Young-Moo; Cho, Young-Su

2018-03-28

We have previously found that mycelia culture broth of eight kinds of traditional herbal extracts fermented with Phellinus linteus (previously named as 8-HsPLCB) not only inhibited melanin and tyrosinase activity, but also reduced the contents of melanogenesis-related proteins, including tyrosinase and microphthalmia-associated transcription factor, in 3-isobutyl-1-methylxanthine-stimulated B16F0 melanoma cells. For a further study, the effect of 8-HsPLCB against skin pigmentation in brown guinea pigs with ultraviolet B (UVB)-induced hyperpigmentation was investigated. 8-HsPLCB (3%) and arbutin (2%) as positive controls were applied topically twice daily for 4 weeks to the hyperpigmented areas. 8-HsPLCB showed skin-lightening effect as effective as arbutin, one of the most widely used in whitening cosmetics. Melanin index values as the degree of pigmentation showed a significant reduction week by week post 8-HsPLCB treatment and then substantially reduced by 4 weeks. The degree of depigmentation after 4 weeks of topical application with 8-HsPLCB was 32.2% as compared with before treatment (0 week). Moreover, using Fontana-Masson staining and hematoxylin-eosin staining, 8-HsPLCB reduced melanin pigmentation in the basal layer of the epidermis and epidermal thickness changes exposed to the UV-B irradiation as compared with non-treatment and vehicle treatment. The intensity of the skin-lightening effect of 8-HsPLCB was similar to arbutin. These results suggest that the skin-lightening effect of 8-HsPLCB might be resulted from inhibition of melanin synthesis by tyrosinase in melanocytes. To conclude, 8-HsPLCB treatment showed reduction of the melanin pigment and histological changes induced by UV irradiation in brown guinea pigs.

Bifidobacterium breve B-3 exerts metabolic syndrome-suppressing effects in the liver of diet-induced obese mice: a DNA microarray analysis.

PubMed

Kondo, S; Kamei, A; Xiao, J Z; Iwatsuki, K; Abe, K

2013-09-01

We previously reported that supplementation with Bifidobacterium breve B-3 reduced body weight gain and accumulation of visceral fat in a dose-dependent manner, and improved serum levels of total cholesterol, glucose and insulin in a mouse model of diet-induced obesity. In this study, we investigated the expression of genes in the liver using DNA microarray analysis and q-PCR to reveal the mechanism of these anti-obesity effects in this mouse model. Administration of B. breve B-3 led to regulated gene expression of pathways involved in lipid metabolism and response to stress. The results indicate that these regulations in the liver are related to the anti-metabolic syndrome effects of B. breve B-3.

Diarctigenin, a lignan constituent from Arctium lappa, down-regulated zymosan-induced transcription of inflammatory genes through suppression of DNA binding ability of nuclear factor-kappaB in macrophages.

PubMed

Kim, Byung Hak; Hong, Seong Su; Kwon, Soon Woo; Lee, Hwa Young; Sung, Hyeran; Lee, In-Jeong; Hwang, Bang Yeon; Song, Sukgil; Lee, Chong-Kil; Chung, Daehyun; Ahn, Byeongwoo; Nam, Sang-Yoon; Han, Sang-Bae; Kim, Youngsoo

2008-11-01

Diarctigenin was previously isolated as an inhibitor of nitric oxide (NO) production in macrophages from the seeds of Arctium lappa used as an alternative medicine for the treatment of inflammatory disorders. However, little is known about the molecular basis of these effects. Here, we demonstrated that diarctigenin inhibited the production of NO, prostaglandin E(2), tumor necrosis factor-alpha, and interleukin (IL)-1beta and IL-6 with IC(50) values of 6 to 12 miciroM in zymosan- or lipopolysaccharide-(LPS) activated macrophages. Diarctigenin attenuated zymosan-induced mRNA synthesis of inducible NO synthase (iNOS) and also inhibited promoter activities of iNOS and cytokine genes in the cells. Because nuclear factor (NF)-kappaB plays a pivotal role in inflammatory gene transcription, we next investigated the effect of diarctigenin on NF-kappaB activation. Diarctigenin inhibited the transcriptional activity and DNA binding ability of NF-kappaB in zymosan-activated macrophages but did not affect the degradation and phosphorylation of inhibitory kappaB (IkappaB) proteins. Moreover, diarctigenin suppressed expression vector NF-kappaB p65-elicited NF-kappaB activation and also iNOS promoter activity, indicating that the compound could directly target an NF-kappa-activating signal cascade downstream of IkappaB degradation and inhibit NF-kappaB-regulated iNOS expression. Diarctigenin also inhibited the in vitro DNA binding ability of NF-kappaB but did not affect the nuclear import of NF-kappaB p65 in the cells. Taken together, diarctigenin down-regulated zymosan- or LPS-induced inflammatory gene transcription in macrophages, which was due to direct inhibition of the DNA binding ability of NF-kappaB. Finally, this study provides a pharmacological potential of diarctigenin in the NF-kappaB-associated inflammatory disorders.

A Role for the Host DNA Damage Response in Hepatitis B Virus cccDNA Formation—and Beyond?

PubMed Central

Schreiner, Sabrina; Nassal, Michael

2017-01-01

Chronic hepatitis B virus (HBV) infection puts more than 250 million people at a greatly increased risk to develop end-stage liver disease. Like all hepadnaviruses, HBV replicates via protein-primed reverse transcription of a pregenomic (pg) RNA, yielding an unusually structured, viral polymerase-linked relaxed-circular (RC) DNA as genome in infectious particles. Upon infection, RC-DNA is converted into nuclear covalently closed circular (ccc) DNA. Associating with cellular proteins into an episomal minichromosome, cccDNA acts as template for new viral RNAs, ensuring formation of progeny virions. Hence, cccDNA represents the viral persistence reservoir that is not directly targeted by current anti-HBV therapeutics. Eliminating cccDNA will thus be at the heart of a cure for chronic hepatitis B. The low production of HBV cccDNA in most experimental models and the associated problems in reliable cccDNA quantitation have long hampered a deeper understanding of cccDNA molecular biology. Recent advancements including cccDNA-dependent cell culture systems have begun to identify select host DNA repair enzymes that HBV usurps for RC-DNA to cccDNA conversion. While this list is bound to grow, it may represent just one facet of a broader interaction with the cellular DNA damage response (DDR), a network of pathways that sense and repair aberrant DNA structures and in the process profoundly affect the cell cycle, up to inducing cell death if repair fails. Given the divergent interactions between other viruses and the DDR it will be intriguing to see how HBV copes with this multipronged host system. PMID:28531167

Effects of ultraviolet-B exposure of Arabidopsis thaliana on herbivory by two crucifer-feeding insects (Lepidoptera)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grant-Petersson, J.; Renwick, J.A.A.

1996-02-01

Larvae of Pieris rapae (L.) (Lepidoptera: Pieridae) and Trichoplusia ni (Huebner) (Lepidoptera: Noctuidae) were fed foliage from Arabidopsis thaliana (L.) Heynh. plants that had received a high dose of ultraviolet-B (UV-B) or from control plants. Treatments were compared using the Student independent t-test. P. rapae larvae consumed less of the foliage exposed to UV-B than control foliage. This difference as significant in older but not younger larvae, and the older P. rapae larvae fed foliage exposed to UV-B weighed significantly less. For T. ni, however, consumption and larval weights were approximately equal for UV-exposed and control foliage. No significant differencesmore » in growth rates per unit consumption on UV-exposed versus control foliage were found for either species. Chemical analysis showed that flavonoid levels increased in response to UV-B. Results suggested that UV-inducible flavonoids may act as feeding deterrents to P. rapae but not to T. ni. 56 refs., 6 figs.« less

The Role of Inducible DNA Repair in W-Reactivation and Related Phenomena.

DTIC Science & Technology

1981-10-14

unexcised dimers in X DNA. This was consistent with the finding of Tomilin and Mosevitskaya (1975) which showed that the UV-endonuclease from Micrococcus ...of DNA in vitro with UV-endonuclease from Micrococcus luteus. Mutat. Res. 27, 147-156 (1975) Tomizawa, J., Ogawa, T.: Effect of ultraviolet irradiation

Involvement of the Extrinsic and Intrinsic Pathways in Ultraviolet B-Induced Apoptosis of Corneal Epithelial Cells

PubMed Central

Ubels, John L.; Glupker, Courtney D.; Schotanus, Mark P.; Haarsma, Loren D.

2015-01-01

The goal of this study was to elucidate the pathway by which UVB initiates efflux of K+ and subsequently apoptosis in human corneal limbal epithelial (HCLE) cells. The initial focus of the study was on the extrinsic pathway involving Fas. HCLE cells transfected with Fas siRNA were exposed to 80–150 mJ/cm2 UVB and incubated in culture medium with 5.5 mM K+. Knock down of Fas resulted in limited reduction in UVB-induced caspase-8 and -3 activity. Patch-clamp recordings showed no difference in UVB-induced normalized K+ currents between Fas transfected and control cells. Knockdown of caspase-8 had no effect on the activation of caspase-3 following UVB exposure, while a caspase-8 inhibitor completely eliminated UVB activation of caspase-3. This suggests that caspase-8 is a robust enzyme, able to activate caspase-3 via residual caspase-8 present after knockdown, and that caspase-8 is directly involved in the UVB activation of caspase-3. Inhibition of caspase-9 significantly decreased the activation of caspases-8 and -3 in response to UVB. Knockdown of Apaf-1, required for activation of caspase-9, resulted in a significant reduction in UVB-induced activation of caspases-9, -8, and -3. Knockdown of Apaf-1 also inhibited intrinsic and UVB-induced levels of apoptosis, as determined by DNA fragmentation measured by TUNEL assay. In UVB exposed cultures treated with caspase-3 inhibitor, the percentage of apoptotic cells was reduced to control levels, confirming the necessity of caspase-3 activation in DNA fragmentation. The lack of effect of Fas knockdown on K+ channel activation, as well as the limited effect on activation of caspases-8 and -3, strongly suggest that Fas and the extrinsic pathway is not of primary importance in the initiation of apoptosis in response to UVB in HCLE cells. Inhibition of caspase-8 and -3 activation following inhibition of caspase-9, as well as reduction in activation of caspases-9, -8, and -3 and DNA fragmentation in response to Apaf-1

Silver nanoparticles protect human keratinocytes against UVB radiation-induced DNA damage and apoptosis: potential for prevention of skin carcinogenesis

PubMed Central

Arora, Sumit; Tyagi, Nikhil; Bhardwaj, Arun; Rusu, Lilia; Palanki, Rohan; Vig, Komal; Singh, Shree R.; Singh, Ajay P.; Palanki, Srinivas; Miller, Michael E.; Carter, James E.; Singh, Seema

2015-01-01

Ultraviolet (UV)-B radiation from the sun is an established etiological cause of skin cancer, which afflicts more than a million lives each year in the United States alone. Here, we tested the chemopreventive efficacy of silver-nanoparticles (AgNPs) against UVB-irradiation-induced DNA damage and apoptosis in human immortalized keratinocytes (HaCaT). AgNPs were synthesized by reduction-chemistry and characterized for their physicochemical properties. AgNPs were well tolerated by HaCaT cells and their pretreatment protected them from UVB-irradiation-induced apoptosis along with significant reduction in cyclobutane-pyrimidine-dimer formation. Moreover, AgNPs pre-treatment led to G1-phase cell-cycle arrest in UVB-irradiated HaCaT cells. AgNPs were efficiently internalized in UVB-irradiated cells and localized into cytoplasmic and nuclear compartments. Furthermore, we observed an altered expression of various genes involved in cell-cycle, apoptosis and nucleotide-excision repair in HaCaT cells treated with AgNPs prior to UVB-irradiation. Together, these findings provide support for potential utility of AgNPs as novel chemopreventive agents against UVB-irradiation-induced skin carcinogenesis. PMID:25804413

Pterocarpus santalinus L. Regulated Ultraviolet B Irradiation-induced Procollagen Reduction and Matrix Metalloproteinases Expression Through Activation of TGF-β/Smad and Inhibition of the MAPK/AP-1 Pathway in Normal Human Dermal Fibroblasts.

PubMed

Gao, Wei; Lin, Pei; Hwang, Eunson; Wang, Yushuai; Yan, Zhengfei; Ngo, Hien T T; Yi, Tae-Hoo

2018-01-01

Ultraviolet light-induced reactive oxygen species (ROS) damage human skin and prematurely cause aging. A growing body of research is focusing on considering plants and plant-derived compounds as antiphotoaging therapeutic material. Pterocarpus santalinus L., as an Indian traditional medicine, possesses antidiabetic, anti-inflammatory and antioxidative effects. Here, we studied the antiphotoaging effects of ethanolic extract of P. santalinus L. heartwood (EPS) on ultraviolet radiation B (UVB)-irradiated normal human dermal fibroblasts (NHDFs). Results showed that EPS significantly inhibited the upregulation of matrix metalloproteinases and IL-6 caused by UVB irradiation, and suppressed UVB-induced phosphorylation of extracellular signal-regulated kinase, Jun N-terminal kinase and p38, as well as the activation of AP-1 transcription factors. Further study indicated that UVB-induced production of MMP-1 and IL-6 could be inhibited by PD 98059 (an ERK inhibitor) and SP600125 (A JNK inhibitor), implied that EPS inhibited UVB-induced MMP-1 and IL-6 secretion by inactivating MAPK signaling pathway. In addition, EPS possessed an excellent antioxidant activity, which could increase cytoprotective antioxidants such as HO-1, NQ-O1 expression by facilitating the nuclear accumulation of Nrf2. Treatment of NHDFs with EPS also recovered UVB-induced procollagen type I reduction by activating TGF-β/Smad pathway. These findings demonstrated that EPS had a potential effect against UVB-induced skin photoaging. © 2017 The American Society of Photobiology.

The ethyl acetate fraction of Sargassum muticum attenuates ultraviolet B radiation-induced apoptotic cell death via regulation of MAPK- and caspase-dependent signaling pathways in human HaCaT keratinocytes.

PubMed

Piao, Mei Jing; Kim, Ki Cheon; Zheng, Jian; Yao, Cheng Wen; Cha, Ji Won; Boo, Sun Jin; Yoon, Weon Jong; Kang, Hee Kyoung; Yoo, Eun Sook; Koh, Young Sang; Ko, Mi Hee; Lee, Nam Ho; Hyun, Jin Won

2014-09-01

Our previous work demonstrated that an ethyl acetate extract derived from Sargassum muticum (Yendo) Fenshol (SME) protected human HaCaT keratinocytes against ultraviolet B (UVB)-induced oxidative stress by increasing antioxidant activity in the cells, thereby inhibiting apoptosis. The aim of the current study was to further elucidate the anti-apoptotic mechanism of SME against UVB-induced cell damage. The expression levels of several apoptotic-associated and mitogen-activated kinase (MAPK) signaling proteins were determined by western blot analysis of UVB-irradiated HaCaT cells with or without prior SME treatment. In addition, the loss of mitochondrial membrane potential (Δψm) was detected using flow cytometry or confocal microscopy and the mitochondria membrane-permeate dye, JC-1. Apoptosis was assessed by quantifying DNA fragmentation and apoptotic body formation. Furthermore, cell viability was evaluated using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. SME absorbed electromagnetic radiation in the UVB range (280-320 nm) of the UV/visible light spectrum. SME also increased Bcl-2 and Mcl-1 expression in UVB-irradiated cells and decreased the Bax expression. Moreover, SME inhibited the UVB-induced disruption of mitochondrial membrane potential and prevented UVB-mediated increases in activated caspase-9 and caspase-3 (an apoptotic initiator and executor, respectively) levels. Notably, treatment with a pan-caspase inhibitor enhanced the anti-apoptotic effects of SME in UVB-irradiated cells. Finally, SME reduced the UVB-mediated phosphorylation of p38 MAPK and JNK, and prevented the UVB-mediated dephosphorylation of Erk1/2 and Akt. The present results indicate that SME safeguards HaCaT keratinocytes from UVB-mediated apoptosis by inhibiting a caspase-dependent signaling pathway.

DNA sensing via the Stimulator of Interferon Genes (STING) adaptor in myeloid dendritic cells induces potent tolerogenic responses1

PubMed Central

Huang, Lei; Li, Lingqian; Lemos, Henrique; Chandler, Phillip R.; Pacholczyk, Gabriela; Baban, Babak; Barber, Glen N.; Hayakawa, Yoshihiro; McGaha, Tracy L.; Ravishankar, Buvana; Munn, David H.; Mellor, Andrew L.

2013-01-01

Cytosolic DNA sensing via the STING adaptor incites autoimmunity by inducing type I IFN (IFNαβ). Here we show that DNA is also sensed via STING to suppress immunity by inducing indoleamine 2,3 dioxygenase (IDO). STING gene ablation abolished IFNαβ and IDO induction by dendritic cells (DCs) after DNA nanoparticle (DNP) treatment. Marginal zone macrophages, some DCs and myeloid cells ingested DNPs but CD11b+ DCs were the only cells to express IFNβ, while CD11b+ non-DCs were major IL-1β producers. STING ablation also abolished DNP-induced regulatory responses by DCs and regulatory T cells (Tregs), and hallmark regulatory responses to apoptotic cells were also abrogated. Moreover, systemic cyclic diguanylate monophosphate (c-diGMP) treatment to activate STING induced selective IFNβ expression by CD11b+ DCs and suppressed Th1 responses to immunization. Thus, previously unrecognized functional diversity amongst physiologic innate immune cells regarding DNA sensing via STING is pivotal in driving immune responses to DNA. PMID:23986532

Thioredoxin-mediated denitrosylation regulates cytokine-induced nuclear factor κB (NF-κB) activation.

PubMed

Kelleher, Zachary T; Sha, Yonggang; Foster, Matthew W; Foster, W Michael; Forrester, Michael T; Marshall, Harvey E

2014-01-31

S-nitrosylation of nuclear factor κB (NF-κB) on the p65 subunit of the p50/p65 heterodimer inhibits NF-κB DNA binding activity. We have recently shown that p65 is constitutively S-nitrosylated in the lung and that LPS-induced injury elicits a decrease in SNO-p65 levels concomitant with NF-κB activation in the respiratory epithelium and initiation of the inflammatory response. Here, we demonstrate that TNFα-mediated activation of NF-κB in the respiratory epithelium similarly induces p65 denitrosylation. This process is mediated by the denitrosylase thioredoxin (Trx), which becomes activated upon cytokine-induced degradation of thioredoxin-interacting protein (Txnip). Similarly, inhibition of Trx activity in the lung attenuates LPS-induced SNO-p65 denitrosylation, NF-κB activation, and airway inflammation, supporting a pathophysiological role for this mechanism in lung injury. These data thus link stimulus-coupled activation of NF-κB to a specific, protein-targeted denitrosylation mechanism and further highlight the importance of S-nitrosylation in the regulation of the immune response.

Engagement of Components of DNA-Break Repair Complex and NFκB in Hsp70A1A Transcription Upregulation by Heat Shock.

PubMed

Hazra, Joyita; Mukherjee, Pooja; Ali, Asif; Poddar, Soumita; Pal, Mahadeb

2017-01-01

An involvement of components of DNA-break repair (DBR) complex including DNA-dependent protein kinase (DNA-PK) and poly-ADP-ribose polymerase 1 (PARP-1) in transcription regulation in response to distinct cellular signalling has been revealed by different laboratories. Here, we explored the involvement of DNA-PK and PARP-1 in the heat shock induced transcription of Hsp70A1A. We find that inhibition of both the catalytic subunit of DNA-PK (DNA-PKc), and Ku70, a regulatory subunit of DNA-PK holo-enzyme compromises transcription of Hsp70A1A under heat shock treatment. In immunoprecipitation based experiments we find that Ku70 or DNA-PK holoenzyme associates with NFκB. This NFκB associated complex also carries PARP-1. Downregulation of both NFκB and PARP-1 compromises Hsp70A1A transcription induced by heat shock treatment. Alteration of three bases by site directed mutagenesis within the consensus κB sequence motif identified on the promoter affected inducibility of Hsp70A1A transcription by heat shock treatment. These results suggest that NFκB engaged with the κB motif on the promoter cooperates in Hsp70A1A activation under heat shock in human cells as part of a DBR complex including DNA-PK and PARP-1.

Non-B-Form DNA Is Enriched at Centromeres

PubMed Central

Henikoff, Steven

2018-01-01

Abstract Animal and plant centromeres are embedded in repetitive “satellite” DNA, but are thought to be epigenetically specified. To define genetic characteristics of centromeres, we surveyed satellite DNA from diverse eukaryotes and identified variation in <10-bp dyad symmetries predicted to adopt non-B-form conformations. Organisms lacking centromeric dyad symmetries had binding sites for sequence-specific DNA-binding proteins with DNA-bending activity. For example, human and mouse centromeres are depleted for dyad symmetries, but are enriched for non-B-form DNA and are associated with binding sites for the conserved DNA-binding protein CENP-B, which is required for artificial centromere function but is paradoxically nonessential. We also detected dyad symmetries and predicted non-B-form DNA structures at neocentromeres, which form at ectopic loci. We propose that centromeres form at non-B-form DNA because of dyad symmetries or are strengthened by sequence-specific DNA binding proteins. This may resolve the CENP-B paradox and provide a general basis for centromere specification. PMID:29365169

UV-B Radiation Induces Root Bending Through the Flavonoid-Mediated Auxin Pathway in Arabidopsis

PubMed Central

Wan, Jinpeng; Zhang, Ping; Wang, Ruling; Sun, Liangliang; Wang, Wenying; Zhou, Huakun; Xu, Jin

2018-01-01

Ultraviolet (UV)-B radiation-induced root bending has been reported; however, the underlying mechanisms largely remain unclear. Here, we investigate whether and how auxin and flavonoids are involved in UV-B radiation-induced root bending in Arabidopsis using physiological, pharmacological, and genetic approaches. UV-B radiation modulated the direction of root growth by decreasing IAA biosynthesis and affecting auxin distribution in the root tips, where reduced auxin accumulation and asymmetric auxin distribution were observed. UV-B radiation increased the distribution of auxin on the nonradiated side of the root tips, promoting growth and causing root bending. Further analysis indicated that UV-B induced an asymmetric accumulation of flavonoids; this pathway is involved in modulating the accumulation and asymmetric distribution of auxin in root tips and the subsequent redirection of root growth by altering the distribution of auxin carriers in response to UV-B radiation. Taken together, our results indicate that UV-B radiation-induced root bending occurred through a flavonoid-mediated phototropic response to UV-B radiation. PMID:29868074

Microcystin-LR induced DNA damage in human peripheral blood lymphocytes.

PubMed

Zegura, B; Gajski, G; Straser, A; Garaj-Vrhovac, V; Filipič, M

2011-12-24

Human exposure to microcystins, which are produced by freshwater cyanobacterial species, is of growing concern due to increasing appearance of cyanobacterial blooms as a consequence of global warming and increasing water eutrophication. Although microcystins are considered to be liver-specific, there is evidence that they may also affect other tissues. These substances have been shown to induce DNA damage in vitro and in vivo, but the mechanisms of their genotoxic activity remain unclear. In human peripheral blood lymphocytes (HPBLs) exposure to non-cytotoxic concentrations (0, 0.1, 1 and 10μg/ml) of microcystin-LR (MCLR) induced a dose- and time-dependent increase in DNA damage, as measured with the comet assay. Digestion of DNA from MCLR-treated HPBLs with purified formamidopyrimidine-DNA glycosylase (Fpg) displayed a greater number of DNA strand-breaks than non-digested DNA, confirming the evidence that MCLR induces oxidative DNA damage. With the cytokinesis-block micronucleus assay no statistically significant induction of micronuclei, nucleoplasmic bridges and nuclear buds was observed after a 24-h exposure to MCLR. At the molecular level, no changes in the expression of selected genes involved in the cellular response to DNA damage and oxidative stress were observed after a 4-h exposure to MCLR (1μg/ml). After 24h, DNA damage-responsive genes (p53, mdm2, gadd45a, cdkn1a), a gene involved in apoptosis (bax) and oxidative stress-responsive genes (cat, gpx1, sod1, gsr, gclc) were up-regulated. These results provide strong support that MCLR is an indirectly genotoxic agent, acting via induction of oxidative stress, and that lymphocytes are also the target of microcystin-induced toxicity. Copyright © 2011 Elsevier B.V. All rights reserved.

Protective mechanisms and acclimation to solar ultraviolet-B radiation in Oenothera stricta

NASA Technical Reports Server (NTRS)

Robberecht, R.; Caldwell, M. M.

1981-01-01

Plant adaptations ameliorating or repairing the damaging effects of ultraviolet-B (UV-B) radiation on plant tissue were investigated. The degree of phenotype plasticity in UV protective mechanisms and acclimation in relation to the natural solar UV-B radiation flux and in an enhanced UV-B irradiance environment was also examined. Mechanisms by which plants avoid radiation, adaptations altering the path of radiation incident on the leaf, and repair processes were considered. Attenuation of UV-B by tissues, UV-B irradiation into the leaf, and the effects of UV-B on photosynthesis were investigated.

Raman spectroscopic study of plasma-treated salmon DNA

NASA Astrophysics Data System (ADS)

Joon Lee, Geon; Kwon, Young-Wan; Hee Kim, Yong; Ha Choi, Eun

2013-01-01

In this research, we studied the effect of plasma treatment on the optical/structural properties of the deoxyribonucleic acid (DNA) extracted from salmon sperm. DNA-cetyltrimethylammonium (CTMA) films were obtained by complexation of DNA with CTMA. Circular dichroism (CD) and Raman spectra indicated that DNA retained its double helical structure in the solid film. The Raman spectra exhibited several vibration modes corresponding to the nuclear bases and the deoxyribose-phosphate backbones of the DNA, as well as the alkylchains of CTMA. Dielectric-barrier-discharge (DBD) plasma treatment induced structural modification and damage to the DNA, as observed by changes in the ultraviolet-visible absorption, CD, and Raman spectra. The optical emission spectra of the DBD plasma confirmed that DNA modification was induced by plasma ions such as reactive oxygen species and reactive nitrogen species.

Mutation and repair in an ultraviolet-sensitive Chinese hamster ovary cell line

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, R.D.

1981-11-01

An ultraviolet (UV) light-sensitive mutant of Chinese hamster ovary cells (CHO) has been isolated and characterized with respect to a number of post-irradiation responses. The UV-sensitive mutant, termed 43-3B, has the same growth rate and chromosome number as the wild-type CHO-9. 43-3B is hypersensitive to the lethal effects of UV light (D/sub 0/ of 0.3 J/m/sup 2/ as compared to 3.2 J/m/sup 2/ for the wild-type). A marked UV-hypermutability is observed in 43-3B as compared to the wild-type, as measured with markers for induced resistance to 6-thioguanine, ouabain, and diphtheria toxin. A factor of 38 to 65 more mutations aremore » induced per unit fluence in 43-3B than in CHO-9. The UV-sensitive mutant is also sensitive to killing by simulated solar light, although the D/sub 0/ ratio is not as great as for germicidal UV. 43-3B exhibits only about 17% of the wild-type level of UV-stimulated DNA repair synthesis, as measured by autoradiography of G/sub 1/ phase cells. A much reduced ability to recover control rates of semiconservative DNA synthesis after UV irradiation was observed in the repair-deficient 43-3B cell line. Recovery of colony-forming ability between fractionated UV exposures was observed in the wild-type CHO-9, but little recovery was seen in 43-3B. The present investigation demonstrates that a sensitive/wild-type pair of CHO cell lines can be used in comparative studies to determine the involvement of repair in a wide range of post-irradiation phenomena.« less

Efficient production of native lunasin with correct N-terminal processing by using the pH-induced self-cleavable Ssp DnaB mini-intein system in Escherichia coli.

PubMed

Setrerrahmane, Sarra; Zhang, Yi; Dai, Guangzhi; Lv, Jing; Tan, Shuhua

2014-09-01

To develop an efficient and cost-effective approach for the production of small preventive peptide lunasin with correct natural N terminus, a synthetic gene was designed by OPTIMIZER & Gene Designer and cloned into pTWIN1 vector at SapI and PstI sites. Thus, lunasin was N-terminally fused to the pH-induced self-cleavable Ssp DnaB mini-intein linked to a chitin binding domain (CBD) with no extra residues. The resultant fusion protein was highly expressed by lactose induction in Escherichia coli BL21 (DE3) in a 7-l bioreactor and bound to a chitin affinity column. After washing the impurities, the Ssp DnaB intein mediated on-column self-cleavage was easily triggered by shifting pH and temperature to allow the native lunasin released. The final purified lunasin yielded up to 75 mg/l medium. Tricine/SDS-PAGE and matrix-assisted laser desorption time-of-flight (MALDI-TOF)/mass spectrometry (MS) verified the structural authenticity of the product, implying the correct cleavage at the junction between Ssp DnaB intein and lunasin. MTT assay confirmed its potent proliferation inhibitory activity to human cancer cells HCT-116 and MDA-MB-231; however, no cytotoxicity to normal human lens epithelial cell SRA01/04 and hepatoma HepG2. Taken together, we provide a novel strategy to produce recombinant native lunasin with correct N-terminal processing by using the pH-induced self-cleavable Ssp DnaB mini-intein.

Ultraviolet-B radiation in a row-crop canopy: an extended 1-D model

Treesearch

Wei Gao; Richard H. Grant; Gordon M. Heisler; James R. Slusser

2003-01-01

A decrease in stratospheric ozone may result in a serious threat to plants, since biologically active short-wavelength ultraviolet-B (UV-B 280-320 nm) radiation will increase even with a relatively small decrease in ozone. Numerous investigations have demonstrated that the effect of UV-B enhancements on plants includes reduction in grain yield, alteration in species...

UV-B radiation-induced oxidative stress and p38 signaling pathway involvement in the benthic copepod Tigriopus japonicus.

PubMed

Kim, Bo-Mi; Rhee, Jae-Sung; Lee, Kyun-Woo; Kim, Min-Jung; Shin, Kyung-Hoon; Lee, Su-Jae; Lee, Young-Mi; Lee, Jae-Seong

2015-01-01

Ultraviolet B (UV-B) radiation presents an environmental hazard to aquatic organisms. To understand the molecular responses of the intertidal copepod Tigriopus japonicus to UV-B radiation, we measured the acute toxicity response to 96 h of UV-B radiation, and we also assessed the intracellular reactive oxygen species (ROS) levels, glutathione (GSH) content, and antioxidant enzyme (GST, GR, GPx, and SOD) activities after 24 h of exposure to UV-B with LD50 and half LD50 values. Also, expression patterns of p53 and hsp gene families with phosphorylation of p38 MAPK were investigated in UV-B-exposed copepods. We found that the ROS level, GSH content, and antioxidant enzyme activity levels were increased with the transcriptional upregulation of antioxidant-related genes, indicating that UV-B induces oxidative stress by generating ROS and stimulating antioxidant enzymatic activity as a defense mechanism. Additionally, we found that p53 expression was significantly increased after UV-B irradiation due to increases in the phosphorylation of the stress-responsive p38 MAPK, indicating that UV-B may be responsible for inducing DNA damage in T. japonicus. Of the hsp family genes, transcriptional levels of hsp20, hsp20.7, hsp70, and hsp90 were elevated in response to a low dose of UV-B radiation (9 kJ m(-2)), suggesting that these hsp genes may be involved in cellular protection against UV-B radiation. In this paper, we performed a pathway-oriented mechanistic analysis in response to UV-B radiation, and this analysis provides a better understanding of the effects of UV-B in the intertidal benthic copepod T. japonicus. Copyright © 2014 Elsevier Inc. All rights reserved.

Transcriptional regulation of ataxia-telangiectasia and Rad3-related protein by activated p21-activated kinase-1 protects keratinocytes in UV-B-induced premalignant skin lesions.

PubMed

Beesetti, S; Mavuluri, J; Surabhi, R P; Oberyszyn, T M; Tober, K; Pitani, R S; Joseph, L D; Venkatraman, G; Rayala, S K

2017-11-02

Sun-induced skin lesions, in particular actinic keratosis, are generally considered as premalignant skin lesions that can progress into squamous cell carcinoma (SCC) and invasive SCC if left untreated. Therefore, understanding the molecular mechanisms by which the ultraviolet-B (UV-B)-exposed cells are being protected and the signaling pathways that promote the progression of certain premalignant skin lesions to malignant lesions will permit us to prevent or cure skin cancers. In the current study, we found that phospho-p21-activated kinase-1 (Pak1) and Pak1 expression was high in clinical samples of sunlight-induced premalignant skin lesions assessed by immunohistochemistry. Further, we observed that phospho-Pak1 and Pak1 levels are high in UV-B-exposed hairless SKH mouse model skin samples as compared with unexposed skin tissue. Our results from cell line and animal models showed that Pak1 is activated in response to UV-B radiation, and this activated Pak1 translocates from the cytoplasm to the nucleus. Inside the nucleus, Pak1 via C-Fos binds to a specific promoter region of DNA repair kinase ATR (ataxia-telangiectasia and Rad3-related protein) and acts as a transcriptional regulator of ATR. Results from our analysis showed that Pak1 overexpression, knockdown and Pak1 knockout cell line models showed that Pak1 confers protection to keratinocytes from UV-B-induced apoptosis and DNA damage via ATR. To our knowledge, this is the first study that evaluates the functional and clinical significance of a signaling molecule, Pak1, in sun-induced premalignant skin lesions and indicates that increased Pak1 activation and expression could serve as an early warning sign of progression toward non-melanoma skin cancer, if ignored.

Increased susceptibility to in vitro ultraviolet B radiation in fibroblasts and lymphocytes cultured from systemic lupus erythematosus patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Golan, T.D.; Foltyn, V.; Roueff, A.

1991-02-01

Sunlight is known to induce exacerbations of systemic lupus erythematosus (SLE) but its mechanism remains unclear. We have previously reported that ultraviolet A (UVA) exposure induces an increase in total DNA synthesis (DS) in vitro but a decrease in unscheduled DNA repair synthesis (UDRS) of splenocytes of murine SLE strains. In order to investigate whether similar observations are characteristic of human SLE, peripheral blood lymphocytes (PBL) and dermal fibroblast (DF) cultures of 20 patients and 15 matched controls were exposed in vitro to UVA or UVB at different doses. Thirteen (65%) SLE DF cultures exposed to UVB light (12-24 J/m2)more » showed an increase in DS compared to paired unirradiated cultures. In contrast, UVB-irradiated DF from normal individuals had no significant increase in DS following UVB irradiation. When SLE DF were exposed to higher doses of UVB (48-96 J/m2), 90% of cultures showed a decrease in DS compared to only 20% in the control group. All of the SLE DF cultures showed a decrease of their unscheduled DNA repair capacity following UVB (24-48 J/m2) irradiation whereas no UDRS was apparent in 74% of controls under the same conditions. Similar findings regarding UDRS were observed in SLE PBL cultures and were also confirmed by autoradiography. UVA exposure (0-3840 J/m2) had no effect on DS nor on UDRS in DF or PBL cultured from SLE and controls. The relevance of these in vitro findings to the in vivo pathogenesis of the disease is discussed.« less

Effects of soluble and particulate Cr(VI) on genome-wide DNA methylation in human B lymphoblastoid cells.

PubMed

Lou, Jianlin; Wang, Yu; Chen, Junqiang; Ju, Li; Yu, Min; Jiang, Zhaoqiang; Feng, Lingfang; Jin, Lingzhi; Zhang, Xing

2015-10-01

Several previous studies highlighted the potential epigenetic effects of Cr(VI), especially DNA methylation. However, few studies have compared the effects of Cr(VI) on DNA methylation profiles between soluble and particulate chromate in vitro. Accordingly, Illumina Infinium Human Methylation 450K BeadChip array was used to analyze DNA methylation profiles of human B lymphoblastoid cells exposed to potassium dichromate or lead chromate, and the cell viability was also studied. Array based DNA methylation analysis showed that the impacts of Cr(VI) on DNA methylation were limited, only about 40 differentially methylated CpG sites, with an overlap of 15CpG sites, were induced by both potassium dichromate and lead chromate. The results of mRNA expression showed that after Cr(VI) treatment, mRNA expression changes of four genes (TBL1Y, FZD5, IKZF2, and KIAA1949) were consistent with their DNA methylation alteration, but DNA methylation changes of other six genes did not correlate with mRNA expression. In conclusion, both of soluble and particulate Cr(VI) could induce a small amount of differentially methylated sites in human B lymphoblastoid cells, and the correlations between DNA methylation changes and mRNA expression varied between different genes. Copyright © 2015 Elsevier B.V. All rights reserved.

Structural changes induced by binding of the high-mobility group I protein to a mouse satellite DNA sequence.

PubMed Central

Slama-Schwok, A; Zakrzewska, K; Léger, G; Leroux, Y; Takahashi, M; Käs, E; Debey, P

2000-01-01

Using spectroscopic methods, we have studied the structural changes induced in both protein and DNA upon binding of the High-Mobility Group I (HMG-I) protein to a 21-bp sequence derived from mouse satellite DNA. We show that these structural changes depend on the stoichiometry of the protein/DNA complexes formed, as determined by Job plots derived from experiments using pyrene-labeled duplexes. Circular dichroism and melting temperature experiments extended in the far ultraviolet range show that while native HMG-I is mainly random coiled in solution, it adopts a beta-turn conformation upon forming a 1:1 complex in which the protein first binds to one of two dA.dT stretches present in the duplex. HMG-I structure in the 1:1 complex is dependent on the sequence of its DNA target. A 3:1 HMG-I/DNA complex can also form and is characterized by a small increase in the DNA natural bend and/or compaction coupled to a change in the protein conformation, as determined from fluorescence resonance energy transfer (FRET) experiments. In addition, a peptide corresponding to an extended DNA-binding domain of HMG-I induces an ordered condensation of DNA duplexes. Based on the constraints derived from pyrene excimer measurements, we present a model of these nucleated structures. Our results illustrate an extreme case of protein structure induced by DNA conformation that may bear on the evolutionary conservation of the DNA-binding motifs of HMG-I. We discuss the functional relevance of the structural flexibility of HMG-I associated with the nature of its DNA targets and the implications of the binding stoichiometry for several aspects of chromatin structure and gene regulation. PMID:10777751

Early exposure to ultraviolet-B radiation decreases immune function later in life

PubMed Central

Ceccato, Emma; Cramp, Rebecca L.; Seebacher, Frank; Franklin, Craig E.

2016-01-01

Amphibians have declined dramatically worldwide. Many of these declines are occurring in areas where no obvious anthropogenic stressors are present. It is proposed that in these areas, environmental factors such as elevated solar ultraviolet-B (UV-B) radiation could be responsible. Ultraviolet-B levels have increased in many parts of the world as a consequence of the anthropogenic destruction of the ozone layer. Amphibian tadpoles are particularly sensitive to the damaging effects of UV-B radiation, with exposure disrupting growth and fitness in many species. Given that UV-B can disrupt immune function in other animals, we tested the hypothesis that early UV-B exposure suppresses the immune responses of amphibian tadpoles and subsequent juvenile frogs. We exposed Limnodynastes peronii tadpoles to sublethal levels of UV-B radiation for 6 weeks after hatching, then examined indices of immune function in both the tadpoles and the subsequent metamorphs. There was no significant effect of UV-B on tadpole leucocyte counts or on their response to an acute antigen (phytohaemagglutinin) challenge. However, early UV-B exposure resulted in a significant reduction in both metamorph leucocyte abundance and their response to an acute phytohaemagglutinin challenge. These data demonstrate that early UV-B exposure can have carry-over effects on later life-history traits even if the applied stressor has no immediately discernible effect. These findings have important implications for our understanding of the effects of UV-B exposure on amphibian health and susceptibility to diseases such as chytridiomycosis. PMID:27668081

Expression of Filaggrin and its Degradation Products in Human Skin Following Erythemal Doses of Ultraviolet B Irradiation.

PubMed

Simonsen, Stine; Thyssen, Jacob P; Heegaard, Steffen; Kezic, Sanja; Skov, Lone

2017-07-06

Epidermal filaggrin level is affected by ultraviolet B irradiation in animal and experimental models. This study examined the effect of ultraviolet B irradiation on epidermal filaggrin and natural moisturizing factors in vivo in healthy adults (n = 22). Participants were irradiated with 2 minimal erythema doses of ultraviolet B on the skin. Biopsies and tape strips were collected from skin irradiated 24 and 72 h earlier and from non-irradiated skin (control). Real-time quantitative PCR on skin biopsies showed significantly reduced profilaggrin mRNA expression 24 h after irradiation (mean relative mRNA expression ± standard deviation: control, 3.86 ± 2.06 vs. 24 h, 1.52 ± 0.640; p = 0.02; n = 8). Immunohistochemistry showed aberrant spatial distribution of filaggrin protein 72 h after irradiation (n = 3). High-pressure liquid chromatography of tape extracts showed no change in mean total natural moisturizing factor levels after irradiation, but mean trans-urocanic acid was significantly reduced, as expected (n = 8). In conclusion, erythemal doses of ultraviolet B exert acute effects on profilaggrin mRNA and filaggrin protein in human skin in vivo.

Long-term effects of inducible mutagenic DNA repair on relative fitness and phenotypic diversification in Pseudomonas cichorii 302959.

PubMed

Weigand, Michael R; Sundin, George W

2009-01-01

Mutagenic DNA repair (MDR) employs low-fidelity DNA polymerases capable of replicating past DNA lesions resulting from exposure to high-energy ultraviolet radiation (UVR). MDR confers UVR tolerance and activation initiates a transient mutator phenotype that may provide opportunities for adaptation. To investigate the potential role of MDR in adaptation, we have propagated parallel lineages of the highly mutable epiphytic plant pathogen Pseudomonas cichorii 302959 with daily UVR activation (UVR lineages) for approximately 500 generations. Here we examine those lineages through the measurement of relative fitness and observation of distinct colony morphotypes that emerged. Isolates and population samples from UVR lineages displayed gains in fitness relative to the ancestor despite increased rates of inducible mutation to rifampicin resistance. Regular activation of MDR resulted in the maintenance of genetic diversity within UVR lineages, including the reproducible diversification and coexistence of "round" and "fuzzy" colony morphotypes. These results suggest that inducible mutability may present a reasonable strategy for adaptive evolution in stressful environments by contributing to gains in relative fitness and diversification.

The effects of topically applied glycolic acid and salicylic acid on ultraviolet radiation-induced erythema, DNA damage and sunburn cell formation in human skin.

PubMed

Kornhauser, Andrija; Wei, Rong-Rong; Yamaguchi, Yuji; Coelho, Sergio G; Kaidbey, Kays; Barton, Curtis; Takahashi, Kaoruko; Beer, Janusz Z; Miller, Sharon A; Hearing, Vincent J

2009-07-01

alpha-Hydroxy acids (alphaHAs) are reported to reduce signs of aging in the skin and are widely used cosmetic ingredients. Several studies suggest that alphaHA can increase the sensitivity of skin to ultraviolet radiation. More recently, beta-hydroxy acids (betaHAs), or combinations of alphaHA and betaHA have also been incorporated into antiaging skin care products. Concerns have also arisen about increased sensitivity to ultraviolet radiation following use of skin care products containing beta-HA. To determine whether topical treatment with glycolic acid, a representative alphaHA, or with salicylic acid, a betaHA, modifies the short-term effects of solar simulated radiation (SSR) in human skin. Fourteen subjects participated in this study. Three of the four test sites on the mid-back of each subject were treated daily Monday-Friday, for a total of 3.5 weeks, with glycolic acid (10%), salicylic acid (2%), or vehicle (control). The fourth site received no treatment. After the last treatment, each site was exposed to SSR, and shave biopsies from all four sites were obtained. The endpoints evaluated in this study were erythema (assessed visually and instrumentally), DNA damage and sunburn cell formation. Treatment with glycolic acid resulted in increased sensitivity of human skin to SSR, measured as an increase in erythema, DNA damage and sunburn cell formation. Salicylic acid did not produce significant changes in any of these biomarkers. Short-term topical application of glycolic acid in a cosmetic formulation increased the sensitivity of human skin to SSR, while a comparable treatment with salicylic acid did not.

Pollen sensitivity to ultraviolet-B (UV-B) suggests floral structure evolution in alpine plants.

PubMed

Zhang, Chan; Yang, Yong-Ping; Duan, Yuan-Wen

2014-03-31

Various biotic and abiotic factors are known to exert selection pressures on floral traits, but the influence of ultraviolet-B (UV-B) light on the evolution of flower structure remains relatively unexplored. We have examined the effectiveness of flower structure in blocking radiation and the effects of UV-B on pollen viability in 42 species of alpine plants in the Hengduan Mountains, China. Floral forms were categorized as either protecting or exposing pollen grains to UV-B. The floral materials of plants with exposed and protected pollen grains were able to block UV-B at similar levels. Exposure to UV-B radiation in vitro resulted in a significantly greater loss of viability in pollen from plant species with protective floral structures. The pronounced sensitivity of protected pollen to UV-B radiation was associated with the type of flower structure. These findings demonstrate that UV-B plays an important role in the evolution of protective floral forms in alpine plants.

Human SNM1B is required for normal cellular response to both DNA interstrand crosslink-inducing agents and ionizing radiation.

PubMed

Demuth, Ilja; Digweed, Martin; Concannon, Patrick

2004-11-11

DNA interstrand crosslinks (ICLs) are critical lesions for the mammalian cell since they affect both DNA strands and block transcription and replication. The repair of ICLs in the mammalian cell involves components of different repair pathways such as nucleotide-excision repair and the double-strand break/homologous recombination repair pathways. However, the mechanistic details of mammalian ICL repair have not been fully delineated. We describe here the complete coding sequence and the genomic organization of hSNM1B, one of at least three human homologs of the Saccharomyces cerevisiae PSO2 gene. Depletion of hSNM1B by RNA interference rendered cells hypersensitive to ICL-inducing agents. This requirement for hSNM1B in the cellular response to ICL has been hypothesized before but never experimentally verified. In addition, siRNA knockdown of hSNM1B rendered cells sensitive to ionizing radiation, suggesting the possibility of hSNM1B involvement in homologous recombination repair of double-strand breaks arising as intermediates of ICL repair. Monoubiquitination of FANCD2, a key step in the FANC/BRCA pathway, is not affected in hSNM1B-depleted HeLa cells, indicating that hSNM1B is probably not a part of the Fanconi anemia core complex. Nonetheless, similarities in the phenotype of hSNM1B-depleted cells and cultured cells from patients suffering from Fanconi anemia make hSNM1B a candidate for one of the as yet unidentified Fanconi anemia genes not involved in monoubiquitination of FANCD2.

The fate of mitochondrial loci in rho minus mutants induced by ultraviolet irradiation of Saccharomyces cerevisiae: effects of different post-irradiation treatments.

PubMed

Heude, M; Moustacchi, E

1979-09-01

Three main features regarding the loss of mitochondrial genetic markers among rho- mutants induced by ultraviolet irradiation are reported: (a) the frequency of loss of six loci examined increases with UV dose; (b) preferential loss of one region of the mitochondrial genome observed in spontaneous rho- mutants is enhanced by UV; and (c) the loss of each marker results from large deletions. Marker loss in rho- mutants was also investigated under conditions that modulate rho- induction. Liquid holding of irradiated exponential or stationary phase cells, as well as a split-dose regime applied to stationary phase cells, results in rho- mutants in which the loss of markers is correlated with rho- induction: the more sensitive the cells are to rho- induction, the more frequent are the marker losses among rho- clones derived from these cells. This correlation is not found in exponential-phase cells submitted to a split-dose treatment, suggesting that a different mechanism is involved in the latter case. It is known that UV-induced pyrimidine dimers are not excised in a controlled manner in mitochondrial DNA. However, our studies indicate that an accurate repair mechanism (of the recombinational type ?) can lead to the restoration of mitochondrial genetic information in growing cells.

Topically Applied Carvedilol Attenuates Solar Ultraviolet Radiation Induced Skin Carcinogenesis.

PubMed

Huang, Kevin M; Liang, Sherry; Yeung, Steven; Oiyemhonlan, Etuajie; Cleveland, Kristan H; Parsa, Cyrus; Orlando, Robert; Meyskens, Frank L; Andresen, Bradley T; Huang, Ying

2017-10-01

In previous studies, the β-blocker carvedilol inhibited EGF-induced epidermal cell transformation and chemical carcinogen-induced mouse skin hyperplasia. As exposure to ultraviolet (UV) radiation leads to skin cancer, the present study examined whether carvedilol can prevent UV-induced carcinogenesis. Carvedilol absorbs UV like a sunscreen; thus, to separate pharmacological from sunscreen effects, 4-hydroxycarbazole (4-OHC), which absorbs UV to the same degree as carvedilol, served as control. JB6 P + cells, an established epidermal model for studying tumor promotion, were used for evaluating the effect of carvedilol on UV-induced neoplastic transformation. Both carvedilol and 4-OHC (1 μmol/L) blocked transformation induced by chronic UV (15 mJ/cm 2 ) exposure for 8 weeks. However, EGF-mediated transformation was inhibited by only carvedilol but not by 4-OHC. Carvedilol (1 and 5 μmol/L), but not 4-OHC, attenuated UV-induced AP-1 and NF-κB luciferase reporter activity, suggesting a potential anti-inflammatory activity. In a single-dose UV (200 mJ/cm 2 )-induced skin inflammation mouse model, carvedilol (10 μmol/L), applied topically after UV exposure, reduced skin hyperplasia and the levels of cyclobutane pyrimidine dimers, IL1β, IL6, and COX-2 in skin. In SKH-1 mice exposed to gradually increasing levels of UV (50-150 mJ/cm 2 ) three times a week for 25 weeks, topical administration of carvedilol (10 μmol/L) after UV exposure increased tumor latency compared with control (week 18 vs. 15), decreased incidence and multiplicity of squamous cell carcinomas, while 4-OHC had no effect. These data suggest that carvedilol has a novel chemopreventive activity and topical carvedilol following UV exposure may be repurposed for preventing skin inflammation and cancer. Cancer Prev Res; 10(10); 598-606. ©2017 AACR . ©2017 American Association for Cancer Research.

A DETAILED FAR-ULTRAVIOLET SPECTRAL ATLAS OF MAIN-SEQUENCE B STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Myron A.

2010-02-01

We have constructed a detailed spectral atlas covering the wavelength region 930-1225 A for 10 sharp-lined B0-B9 stars near the main sequence. Most of the spectra we assembled are from the archives of the Far Ultraviolet Spectroscopic Explorer satellite, but for nine stars, wavelength coverage above 1188 A was taken from high-resolution International Ultraviolet Explorer or echelle Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra. To represent the tenth star at type B0.2 V, we used the Copernicus atlas of {tau} Sco. We made extensive line identifications in the region 949-1225 A of all atomic features having published oscillator strengths atmore » types B0, B2, and B8. These are provided as a supplementary data product-hence the term detailed atlas. Our list of found features totals 2288, 1612, and 2469 lines, respectively. We were able to identify 92%, 98%, and 98% of these features with known atomic transitions with varying degrees of certainty in these spectra. The remaining lines do not have published oscillator strengths. Photospheric lines account for 94%, 87%, and 91%, respectively, of all our identifications, with the remainder being due to interstellar (usually molecular H{sub 2}) lines. We also discuss the numbers of lines with respect to the distributions of various ions for these three most studied spectral subtypes. A table is also given of 162 least blended lines that can be used as possible diagnostics of physical conditions in B star atmospheres.« less

Identification of transcription coactivator OCA-B-dependent genes involved in antigen-dependent B cell differentiation by cDNA array analyses.

PubMed

Kim, Unkyu; Siegel, Rachael; Ren, Xiaodi; Gunther, Cary S; Gaasterland, Terry; Roeder, Robert G

2003-07-22

The tissue-specific transcriptional coactivator OCA-B is required for antigen-dependent B cell differentiation events, including germinal center formation. However, the identity of OCA-B target genes involved in this process is unknown. This study has used large-scale cDNA arrays to monitor changes in gene expression patterns that accompany mature B cell differentiation. B cell receptor ligation alone induces many genes involved in B cell expansion, whereas B cell receptor and helper T cell costimulation induce genes associated with B cell effector function. OCA-B expression is induced by both B cell receptor ligation alone and helper T cell costimulation, suggesting that OCA-B is involved in B cell expansion as well as B cell function. Accordingly, several genes involved in cell proliferation and signaling, such as Lck, Kcnn4, Cdc37, cyclin D3, B4galt1, and Ms4a11, have been identified as OCA-B-dependent genes. Further studies on the roles played by these genes in B cells will contribute to an understanding of B cell differentiation.

The simultaneous detection of mitochondrial DNA damage from sun-exposed skin of three whale species and its association with UV-induced microscopic lesions and apoptosis.

PubMed

Bowman, Amy; Martinez-Levasseur, Laura M; Acevedo-Whitehouse, Karina; Gendron, Diane; Birch-Machin, Mark A

2013-07-01

Due to life history and physiological constraints, cetaceans (whales) are unable to avoid prolonged exposure to external environmental insults, such as solar ultraviolet radiation (UV). The majority of studies on the effects of UV on skin are restricted to humans and laboratory animals, but it is important to develop tools to understand the effects of UV damage on large mammals such as whales, as these animals are long-lived and widely distributed, and can reflect the effects of UV across a large geographical range. We and others have used mitochondrial DNA (mtDNA) as a reliable marker of UV-induced damage particularly in human skin. UV-induced mtDNA strand breaks or lesions accumulate throughout the lifespan of an individual, thus constituting an excellent biomarker for cumulative exposure. Based on our previous studies in human skin, we have developed for the first time in the literature a quantitative real-time PCR methodology to detect and quantify mtDNA lesions in skin from sun-blistered whales. Furthermore the methodology allows for simultaneous detection of mtDNA damage in different species. Therefore using 44 epidermal mtDNA samples collected from 15 blue whales, 10 fin whales, and 19 sperm whales from the Gulf of California, Mexico, we quantified damage across 4.3 kilobases, a large region of the ~16,400 base pair whale mitochondrial genome. The results show a range of mtDNA damage in the skin of the three different whale species. This previously unreported observation was correlated with apoptotic damage and microscopic lesions, both of which are markers of UV-induced damage. As is the case in human studies, this suggests the potential use of mtDNA as a biomarker for measuring the effect of cumulative UV exposure in whales and may provide a platform to help understand the effects of changing global environmental conditions. Copyright © 2013 Elsevier B.V. and Mitochondria Research Society. All rights reserved. All rights reserved.

DNA and chromosome damage induced by bleomycin in mammalian cells: An update.

PubMed

Bolzán, Alejandro D; Bianchi, Martha S

Bleomycin (BLM) is an antibiotic isolated from Streptomyces verticillus. It has radiomimetic actions on DNA thus it has been widely used in clinical chemotherapy for the treatment of different types of cancer, including head and neck tumors, lymphomas, squamous-cell carcinomas and germ-cell tumors. Because of this, the study of BLM genotoxicity is of practical interest. This antibiotic is an S-independent clastogen and an agent that generates free radicals and induces single- and double-strand breaks in DNA. In the present review, we will summarize our current knowledge concerning the DNA and chromosome damage induced by BLM in mammalian cells, with emphasis on new developments published since 1991. Copyright © 2018 Elsevier B.V. All rights reserved.

Inflammation-Induced Cell Proliferation Potentiates DNA Damage-Induced Mutations In Vivo

PubMed Central

Kiraly, Orsolya; Gong, Guanyu; Olipitz, Werner; Muthupalani, Sureshkumar; Engelward, Bevin P.

2015-01-01

Mutations are a critical driver of cancer initiation. While extensive studies have focused on exposure-induced mutations, few studies have explored the importance of tissue physiology as a modulator of mutation susceptibility in vivo. Of particular interest is inflammation, a known cancer risk factor relevant to chronic inflammatory diseases and pathogen-induced inflammation. Here, we used the fluorescent yellow direct repeat (FYDR) mice that harbor a reporter to detect misalignments during homologous recombination (HR), an important class of mutations. FYDR mice were exposed to cerulein, a potent inducer of pancreatic inflammation. We show that inflammation induces DSBs (γH2AX foci) and that several days later there is an increase in cell proliferation. While isolated bouts of inflammation did not induce HR, overlap between inflammation-induced DNA damage and inflammation-induced cell proliferation induced HR significantly. To study exogenously-induced DNA damage, animals were exposed to methylnitrosourea, a model alkylating agent that creates DNA lesions relevant to both environmental exposures and cancer chemotherapy. We found that exposure to alkylation damage induces HR, and importantly, that inflammation-induced cell proliferation and alkylation induce HR in a synergistic fashion. Taken together, these results show that, during an acute bout of inflammation, there is a kinetic barrier separating DNA damage from cell proliferation that protects against mutations, and that inflammation-induced cell proliferation greatly potentiates exposure-induced mutations. These studies demonstrate a fundamental mechanism by which inflammation can act synergistically with DNA damage to induce mutations that drive cancer and cancer recurrence. PMID:25647331

Clinical evaluation of the branched DNA assay for hepatitis B virus DNA detection in patients with chronic hepatitis B lacking hepatitis B e antigen and treated with interferon-alpha.

PubMed

Habersetzer, F; Zoulim, F; Jusot, J F; Zhang, X; Trabaud, M A; Chevallier, P; Chevallier, M; Ahmed, S N; Sepetjan, M; Comanor, L; Minor, J; Trépo, C

1998-11-01

The aim of this study was to evaluate the Chiron branched DNA (bDNA) assay for detection of serum hepatitis B virus (HBV) DNA in patients with chronic hepatitis B lacking hepatitis B e antigen (HBeAg) and undergoing interferon (IFN) therapy. Results obtained with the bDNA assay were compared with those obtained using the Abbott liquid hybridization (LH) assay and the polymerase chain reaction (PCR). Serial samples (274) from 34 patients were analysed. Analysis of variance results indicated that bDNA values were more significantly correlated than LH values with both PCR positive/negative results (probability of artifact (Prob > F) = 0.7 and 0.09 for LH and bDNA assays, respectively) and presence/absence of precore mutations (Prob > F = 0.21 and 0.001 for LH and bDNA assays, respectively). Both bDNA and LH results correlated highly with alanine aminotransferase (ALT) values (both had Prob > F values of 0.0) while PCR was not correlated with ALT (Prob > F = 0.05). In 26 evaluable patients, a model based on a generalized Knodell score was used to predict response to IFN therapy, as defined by normalization of ALT values during therapy. This model discriminated well between non-responders and responders. The bDNA results correlated well with the generalized Knodell score, while the LH results did not (Prob > F = 0.04 and 0.19 for the bDNA and LH assays, respectively). In conclusion, the bDNA assay appears to be useful for quantification of HBV DNA levels in HBeAg-negative chronic hepatitis as it correlates with biochemical and histological indications of disease severity as well as with response to IFN therapy.

Ultraviolet radiation and nanoparticle induced intracellular free radicals generation measured in human keratinocytes by electron paramagnetic resonance spectroscopy.

PubMed

Rancan, F; Nazemi, B; Rautenberg, S; Ryll, M; Hadam, S; Gao, Q; Hackbarth, S; Haag, S F; Graf, C; Rühl, E; Blume-Peytavi, U; Lademann, J; Vogt, A; Meinke, M C

2014-05-01

Several nanoparticle-based formulations used in cosmetics and dermatology are exposed to sunlight once applied to the skin. Therefore, it is important to study possible synergistic effects of nanoparticles and ultraviolet radiation. Electron paramagnetic resonance spectroscopy (EPR) was used to detect intracellular free radicals induced by ultraviolet B (UVB) radiation and amorphous silica nanoparticle and to evaluate the influence of nanoparticle surface chemistry on particle cytotoxicity toward HaCaT cells. Uncoated titanium dioxide nanoparticles served as positive control. In addition, particle intracellular uptake, viability, and induction of interleukin-6 were measured. We found that photo-activated titanium dioxide particles induced a significant amount of intracellular free radicals. On the contrary, no intracellular free radicals were generated by the investigated silica nanoparticles in the dark as well as under UVB radiation. However, under UVB exposure, the non-functionalized silica nanoparticles altered the release of IL-6. At the same concentrations, the amino-functionalized silica nanoparticles had no influence on UVB-induced IL-6 release. EPR spectroscopy is a useful technique to measure nanoparticle-induced intracellular free radicals. Non-toxic concentrations of silica particles enhanced the toxicity of UVB radiation. This synergistic effect was not mediated by particle-generated free radicals and correlated with particle surface charge and intracellular distribution. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

DNA Repair and Photoprotection: Mechanisms of Overcoming Environmental Ultraviolet Radiation Exposure in Halophilic Archaea

PubMed Central

Jones, Daniel L.; Baxter, Bonnie K.

2017-01-01

Halophilic archaea push the limits of life at several extremes. In particular, they are noted for their biochemical strategies in dealing with osmotic stress, low water activity and cycles of desiccation in their hypersaline environments. Another feature common to their habitats is intense ultraviolet (UV) radiation, which is a challenge that microorganisms must overcome. The consequences of high UV exposure include DNA lesions arising directly from bond rearrangement of adjacent bipyrimidines, or indirectly from oxidative damage, which may ultimately result in mutation and cell death. As such, these microorganisms have evolved a number of strategies to navigate the threat of DNA damage, which we differentiate into two categories: DNA repair and photoprotection. Photoprotection encompasses damage avoidance strategies that serve as a “first line of defense,” and in halophilic archaea include pigmentation by carotenoids, mechanisms of oxidative damage avoidance, polyploidy, and genomic signatures that make DNA less susceptible to photodamage. Photolesions that do arise are addressed by a number of DNA repair mechanisms that halophilic archaea efficiently utilize, which include photoreactivation, nucleotide excision repair, base excision repair, and homologous recombination. This review seeks to place DNA damage, repair, and photoprotection in the context of halophilic archaea and the solar radiation of their hypersaline environments. We also provide new insight into the breadth of strategies and how they may work together to produce remarkable UV-resistance for these microorganisms. PMID:29033920

DNA Repair and Photoprotection: Mechanisms of Overcoming Environmental Ultraviolet Radiation Exposure in Halophilic Archaea.

PubMed

Jones, Daniel L; Baxter, Bonnie K

2017-01-01

Halophilic archaea push the limits of life at several extremes. In particular, they are noted for their biochemical strategies in dealing with osmotic stress, low water activity and cycles of desiccation in their hypersaline environments. Another feature common to their habitats is intense ultraviolet (UV) radiation, which is a challenge that microorganisms must overcome. The consequences of high UV exposure include DNA lesions arising directly from bond rearrangement of adjacent bipyrimidines, or indirectly from oxidative damage, which may ultimately result in mutation and cell death. As such, these microorganisms have evolved a number of strategies to navigate the threat of DNA damage, which we differentiate into two categories: DNA repair and photoprotection. Photoprotection encompasses damage avoidance strategies that serve as a "first line of defense," and in halophilic archaea include pigmentation by carotenoids, mechanisms of oxidative damage avoidance, polyploidy, and genomic signatures that make DNA less susceptible to photodamage. Photolesions that do arise are addressed by a number of DNA repair mechanisms that halophilic archaea efficiently utilize, which include photoreactivation, nucleotide excision repair, base excision repair, and homologous recombination. This review seeks to place DNA damage, repair, and photoprotection in the context of halophilic archaea and the solar radiation of their hypersaline environments. We also provide new insight into the breadth of strategies and how they may work together to produce remarkable UV-resistance for these microorganisms.

A FLUORESCENCE BASED ASSAY FOR DNA DAMAGE INDUCED BY RADIATION, CHEMICAL MUTAGENS AND ENZYMES

EPA Science Inventory

A simple and rapid assay to detect DNA damage is reported. This novel assay is based on changes in melting/annealing behavior and facilitated using certain dyes that increase their fluorescence upon association with double stranded (ds)DNA. Damage caused by ultraviolet (UV) ra...

DNA containing CpG motifs induces angiogenesis

NASA Astrophysics Data System (ADS)

Zheng, Mei; Klinman, Dennis M.; Gierynska, Malgorzata; Rouse, Barry T.

2002-06-01

New blood vessel formation in the cornea is an essential step in the pathogenesis of a blinding immunoinflammatory reaction caused by ocular infection with herpes simplex virus (HSV). By using a murine corneal micropocket assay, we found that HSV DNA (which contains a significant excess of potentially bioactive "CpG" motifs when compared with mammalian DNA) induces angiogenesis. Moreover, synthetic oligodeoxynucleotides containing CpG motifs attract inflammatory cells and stimulate the release of vascular endothelial growth factor (VEGF), which in turn triggers new blood vessel formation. In vitro, CpG DNA induces the J774A.1 murine macrophage cell line to produce VEGF. In vivo CpG-induced angiogenesis was blocked by the administration of anti-mVEGF Ab or the inclusion of "neutralizing" oligodeoxynucleotides that specifically oppose the stimulatory activity of CpG DNA. These findings establish that DNA containing bioactive CpG motifs induces angiogenesis, and suggest that CpG motifs in HSV DNA may contribute to the blinding lesions of stromal keratitis.

Skin protection against UVA-induced iron damage by multiantioxidants and iron chelating drugs/prodrugs.

PubMed

Reelfs, Olivier; Eggleston, Ian M; Pourzand, Charareh

2010-03-01

In humans, prolonged sunlight exposure is associated with various pathological states. The continuing drive to develop improved skin protection involves not only approaches to reduce DNA damage by solar ultraviolet B (UVB) but also the development of methodologies to provide protection against ultraviolet A (UVA), the oxidising component of sunlight. Furthermore identification of specific cellular events following ultraviolet (UV) irradiation is likely to provide clues as to the mechanism of the development of resulting pathologies and therefore strategies for protection. Our discovery that UVA radiation, leads to an immediate measurable increase in 'labile' iron in human skin fibroblasts and keratinocytes provides a new insight into UVA-induced skin damage, since iron is a catalyst of biological oxidations. The main purpose of this overview is to bring together some of the new findings related to mechanisms underlying UVA-induced iron release and to discuss novel approaches based on the use of multiantioxidants and light-activated caged-iron chelators for efficient protection of skin cells against UVA-induced iron damage.

Structural basis for the suppression of skin cancers by DNA polymerase [eta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silverstein, Timothy D.; Johnson, Robert E.; Jain, Rinku

2010-09-13

DNA polymerase {eta} (Pol{eta}) is unique among eukaryotic polymerases in its proficient ability for error-free replication through ultraviolet-induced cyclobutane pyrimidine dimers, and inactivation of Pol{eta} (also known as POLH) in humans causes the variant form of xeroderma pigmentosum (XPV). We present the crystal structures of Saccharomyces cerevisiae Pol{eta} (also known as RAD30) in ternary complex with a cis-syn thymine-thymine (T-T) dimer and with undamaged DNA. The structures reveal that the ability of Pol{eta} to replicate efficiently through the ultraviolet-induced lesion derives from a simple and yet elegant mechanism, wherein the two Ts of the T-T dimer are accommodated in anmore » active site cleft that is much more open than in other polymerases. We also show by structural, biochemical and genetic analysis that the two Ts are maintained in a stable configuration in the active site via interactions with Gln55, Arg73 and Met74. Together, these features define the basis for Pol{eta}'s action on ultraviolet-damaged DNA that is crucial in suppressing the mutagenic and carcinogenic consequences of sun exposure, thereby reducing the incidence of skin cancers in humans.« less

In vitro protective effects of an aqueous extract of Clitoria ternatea L. flower against hydrogen peroxide-induced cytotoxicity and UV-induced mtDNA damage in human keratinocytes.

PubMed

Zakaria, N N A; Okello, E J; Howes, M-J; Birch-Machin, M A; Bowman, A

2018-06-01

The traditional practice of eating the flowers of Clitoria ternatea L. or drinking their infusion as herbal tea in some of the Asian countries is believed to promote a younger skin complexion and defend against skin aging. This study was conducted to investigate the protective effect of C. ternatea flower water extract (CTW) against hydrogen peroxide-induced cytotoxicity and ultraviolet (UV)-induced mitochondrial DNA (mtDNA) damage in human keratinocytes. The protective effect against hydrogen peroxide-induced cytotoxicity was determined by 3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay, and mtDNA damage induced by UV was determined by polymerase chain reaction. Preincubation of HaCaT with 100, 250, and 500 μg/ml CTW reduced cytotoxicity effects of H 2 O 2 compared with control (H 2 O 2 alone). CTW also significantly reduced mtDNA damage in UV-exposed HaCaT (p < .05). CTW was chemically-characterized using high resolution liquid chromatography-mass spectrometry. The main compounds detected were assigned as anthocyanins derived from delphinidin, including polyacylated ternatins, and flavonol glycosides derived from quercetin and kaempferol. These results demonstrated the protective effects of C. ternatea flower extracts that contain polyacylated anthocyanins and flavonol glycosides as major constituents, against H 2 O 2 and UV-induced oxidative stress on skin cells, and may provide some explanation for the putative traditional and cosmetic uses of C. ternatea flower against skin aging. Copyright © 2018 John Wiley & Sons, Ltd.

Xeroderma pigmentosum variants have a slow recovery of DNA synthesis after irradiation with ultraviolet light

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cleaver, J.E.; Thomas, G.H.; Park, S.D.

1979-01-01

Human cells (normal and xeroderma pigmentosum variant) irradiated with ultraviolet light and pulse-labelled with (/sup 3/H)thymidine underwent transient decline and recovery of molecular weights of newly synthesized DNA and rates of (/sup 3/H)thymidine incorporation. The ability to synthesize normal-sized DNA recovered more rapidly in both cell types than thymidine incorporation. During recovery cells steadily increased in their ability to replicate normal-sized DNA on damaged templates. The molecular weight versus time curves fitted exponential functions with similar rate constants in normal and heterozygous xeroderma pigmentosum cells, but with a slower rate in two xeroderma pigmentosum variant cell lines. Caffeine added duringmore » the post-irradiation period eliminated the recovery of molecular weights in xeroderma pigmentosum variant but not in normal cells. The recovery of the ability to synthesize normal-sized DNA represents a combination of a number of cellular regulatory processes, some of which are constitutive, and one of which is altered in the xeroderma pigmentosum variant such that recovery becomes slow and caffeine sensitive.« less

Effects of ultraviolet-B radiation on fungal disease development in Cucumis sativus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orth, A.B.; Teramura, A.H.; Sisler, H.D.

1990-09-01

Stratospheric ozone depletion due to increased atmospheric pollutants has received considerable attention because of the potential increase in ultraviolet-B (UV-B, 280-320 nm) radiation that will reach the earth's surface. Three cucumber (Cucumis sativus L.) cultivars were exposed to a daily dose of 11.6 kJ m{sup {minus}2} biologically effective ultraviolet-B (UV-B{sub BE}) radiation in an unshaded greenhouse before and/or after injection by Colletotrichum lagenarium (Pass.) Ell. and Halst. or Cladosporium cucumerinum Ell. and Arth. and analyzed for disease development. Two of these cultivars, Poinsette and Calypso Hybrid, were disease resistant, while the third cultivar, Straight-8, was disease susceptible. Preinfectional treatment ofmore » 1 to 7 days with UV-B{sub BE} in Straight-8 led to greater severity of both diseases. Postinfectional UV treatment did not lead to increased disease severity caused by C. lagenarium, while preinfectional UV treatment in both Straight-8 and Poinsette substantially increased disease severity. Although resistant cultivars Poinsette and Calypso Hybrid showed increased anthracnose disease severity when exposed to UV-B, this effect was apparent only on the cotyledons. Both higher spore concentration and exposure to UV-B radiation resulted in greater disease severity. Of the cucumber cultivars tested for UV-B sensitivity, growth in Poinsette was most sensitive and Calypso Hybrid was least sensitive. These preliminary results indicate that the effects of UV-B radiation on disease development in cucumber vary depending on cultivar, timing and duration of UV-B exposure, inoculation level, and plant age.« less

Repair of Ultraviolet Radiation Damage in Sensitive Mutants of Micrococcus radiodurans

PubMed Central

Moseley, B. E. B.

1969-01-01

Various aspects of the repair of ultraviolet (UV) radiation-induced damage were compared in wild-type Micrococcus radiodurans and two UV-sensitive mutants. Unlike the wild type, the mutants are more sensitive to radiation at 265 nm than at 280 nm. The delay in deoxyribonucleic acid (DNA) synthesis following exposure to UV is about seven times as long in the mutants as in the wild type. All three strains excise UV-induced pyrimidine dimers from their DNA, although the rate at which cytosine-thymine dimers are excised is slower in the mutants. The three strains also mend the single-strand breaks that appear in the irradiated DNA as a result of dimer excision, although the process is less efficient in the mutants. It is suggested that the increased sensitivity of the mutants to UV radiation may be caused by a partial defect in the second step of dimer excision. PMID:5773016

Piperine attenuates UV-R induced cell damage in human keratinocytes via NF-kB, Bax/Bcl-2 pathway: An application for photoprotection.

PubMed

Verma, Ankit; Kushwaha, Hari N; Srivastava, Ajeet K; Srivastava, Saumya; Jamal, Naseem; Srivastava, Kriti; Ray, Ratan Singh

2017-07-01

Chronic ultraviolet radiation (UV-R) exposure causes skin disorders like erythema, edema, hyperpigmentation, photoaging and photocarcinogenesis. Recent research trends of researchers have focused more attention on the identification and use of photo stable natural agents with photoprotective properties. Piperine (PIP), as a plant alkaloid, is an important constituent present in black pepper (Piper nigrum), used widely in ayurvedic and other traditional medicines and has broad pharmacological properties. The study was planned to photoprotective efficacy of PIP in human keratinocyte (HaCaT) cell line. We have assessed the UV-R induced activation of transcription factor NF-κB in coordination with cell death modulators (Bax/Bcl-2 and p21). The LC-MS/MS analysis revealed that PIP was photostable under UV-A/UV-B exposure. PIP (10μg/ml) attenuates the UV-R (A and B) induced phototoxicity of keratinocyte cell line through the restoration of cell viability, inhibition of ROS, and malondialdehyde generation. Further, PIP inhibited UV-R mediated DNA damage, prevented micronuclei formation, and reduced sub-G1 phase in cell cycle, which supported against photogenotoxicity. This study revealed that PIP pretreatment strongly suppressed UV-R induced photodamages. Molecular docking studies suggest that PIP binds at the active site of NF-κB, and thus, preventing its translocation to nucleus. In addition, transcriptional and translational analysis advocate the increased expression of NF-κB and concomitant decrease in IkB-α expression under UV-R exposed cells, favouring the apoptosis via Bax/Bcl-2 and p21 pathways. However, PIP induced expression of IkB-α suppress the NF-κB activity which resulted in suppression of apoptotic marker genes and proteins that involved in photoprotection. Therefore, we suggest the applicability of photostable PIP as photoprotective agent for human use. Copyright © 2017. Published by Elsevier B.V.

Mequindox induced cellular DNA damage via generation of reactive oxygen species.

PubMed

Liu, Jing; Ouyang, Man; Jiang, Jun; Mu, Peiqiang; Wu, Jun; Yang, Qi; Zhang, Caihui; Xu, Weiying; Wang, Lijuan; Huen, Michael S Y; Deng, Yiqun

2012-01-24

Mequindox, a quinoxaline-N-dioxide derivative that possesses antibacterial properties, has been widely used as a feed additive in the stockbreeding industry in China. While recent pharmacological studies have uncovered potential hazardous effects of mequindox, exactly how mequindox induces pathological changes and the cellular responses associated with its consumption remain largely unexplored. In this study, we investigated the cellular responses associated with mequindox treatment. We report here that mequindox inhibits cell proliferation by arresting cells at the G2/M phase of the cell cycle. Interestingly, this mequindox-associated deleterious effect on cell proliferation was observed in human, pig as well as chicken cells, suggesting that mequindox acts on evolutionarily conserved target(s). To further understand the mequindox-host interaction and the mechanism underlying mequindox-induced cell cycle arrest, we measured the cellular content of DNA damage, which is known to perturb cell proliferation and compromise cell survival. Accordingly, using γ-H2AX as a surrogate marker for DNA damage, we found that mequindox treatment induced cellular DNA damage, which paralleled the chemical-induced elevation of reactive oxygen species (ROS) levels. Importantly, expression of the antioxidant enzyme catalase partially alleviated these mequindox-associated effects. Taken together, our results suggest that mequindox cytotoxicity is attributable, in part, to its role as a potent inducer of DNA damage via ROS. © 2011 Elsevier B.V. All rights reserved.

NET formation induced by Pseudomonas aeruginosa cystic fibrosis isolates measured as release of myeloperoxidase-DNA and neutrophil elastase-DNA complexes.

PubMed

Yoo, Dae-goon; Floyd, Madison; Winn, Matthew; Moskowitz, Samuel M; Rada, Balázs

2014-08-01

Cystic fibrosis (CF) airway disease is characterized by Pseudomonas aeruginosa infection and recruitment of neutrophil granulocytes. Neutrophil granule components (myeloperoxidase (MPO), human neutrophil elastase (HNE)), extracellular DNA and P. aeruginosa can all be found in the CF respiratory tract and have all been associated with worsening CF lung function. Pseudomonas-induced formation of neutrophil extracellular traps (NETs) offers a likely mechanism for release of MPO, HNE and DNA from neutrophils. NETs are composed of a DNA backbone decorated with granule proteins like MPO and HNE. Here we sought to examine whether CF clinical isolates of Pseudomonas are capable of inducing NET release from human neutrophil granulocytes. We used two methods to quantify NETs. We modified a previously employed ELISA that detects MPO-DNA complexes and established a new HNE-DNA ELISA. We show that these methods reliably quantify MPO-DNA and HNE-DNA complexes, measures of NET formation. We have found that CF isolates of P. aeruginosa stimulate robust respiratory burst and NET release in human neutrophils. By comparing paired "early" and "late" bacterial isolates obtained from the same CF patient we have found that early isolates induced significantly more NET release than late isolates. Our data support that Pseudomonas-induced NET release represents an important mechanism for release of neutrophil-derived CF inflammatory mediators, and confirm that decreased induction of NET formation is required for long-term adaptation of P. aeruginosa to CF airways. Copyright © 2014 Elsevier B.V. All rights reserved.

Myeloid cell leukaemia 1 has a vital role in retinoic acid-mediated protection of Toll-like receptor 9-stimulated B cells from spontaneous and DNA damage-induced apoptosis.

PubMed

Holm, Kristine L; Indrevaer, Randi L; Myklebust, June Helen; Kolstad, Arne; Moskaug, Jan Øivind; Naderi, Elin H; Blomhoff, Heidi K

2016-09-01

Vitamin A is an essential anti-infective agent with pleiotropic effects on cells of the immune system. The goal of the present study was to unravel the impact of the vitamin A metabolite retinoic acid (RA) on B-cell survival related both to normal B-cell homeostasis and to the detrimental effects imposed by DNA-damaging agents. By combining RA with Toll-like receptor 9 (TLR9) ligands, we show that RA prevents spontaneous, irradiation- and doxorubicin-induced apoptosis of human B cells in an RA receptor-dependent manner. RA-mediated survival involved up-regulation of the anti-apoptotic protein myeloid cell leukemia 1 (MCL1) at the transcriptional level, and knock down of MCL1 by small interfering RNA partially reversed the effects of RA. To ensure that the combination of TLR9-ligands and RA would not promote the survival of malignant B cells, the combined effects of stimulation with RA and TLR9 ligands was assessed on cells from patients with B-cell malignancies. In contrast to the effects on normal B cells, the combination of TLR9 stimulation and RA neither enhanced the MCL1 levels nor inhibited the death of malignant B cells challenged by DNA-damaging agents. Taken together, the present results reveal a vital role of MCL1 in RA-mediated survival of normal B cells. Moreover, the findings suggest that RA in combination with TLR9 ligands might be useful adjuvants in the treatment of B-cell malignancies by selectively protecting normal and not malignant B cells from DNA-damage-induced cell death. © 2016 John Wiley & Sons Ltd.

The Effects of Topically Applied Glycolic Acid and Salicylic Acid on Ultraviolet Radiation-Induced Erythema, DNA Damage and Sunburn Cell Formation in Human Skin

PubMed Central

Kornhauser, Andrija; Wei, Rong-Rong; Yamaguchi, Yuji; Coelho, Sergio G.; Kaidbey, Kays; Barton, Curtis; Takahashi, Kaoruko; Beer, Janusz Z.; Miller, Sharon A.; Hearing, Vincent J.

2009-01-01

Background α-Hydroxy acids (αHA) are reported to reduce signs of aging in the skin and are widely used cosmetic ingredients. Several studies suggest that αHA can increase the sensitivity of skin to ultraviolet radiation. More recently, β-hydroxy acids (βHA), or combinations of αHA and βHA have also been incorporated into antiaging skin care products. Concerns have also arisen about increased sensitivity to ultraviolet radiation following use of skin care products containing β-HA. Objective To determine whether topical treatment with glycolic acid, a representative αHA, or with salicylic acid, a βHA, modifies the short-term effects of solar simulated radiation (SSR) in human skin. Methods Fourteen subjects participated in this study. Three of the four test sites on the mid-back of each subject were treated daily Monday - Friday, for a total of 3.5 weeks, with glycolic acid (10%), salicylic acid (2%), or vehicle (control). The fourth site received no treatment. After the last treatment, each site was exposed to SSR, and shave biopsies from all 4 sites were obtained. The endpoints evaluated in this study were erythema (assessed visually and instrumentally), DNA damage and sunburn cell formation. Results Treatment with glycolic acid resulted in increased sensitivity of human skin to SSR, measured as an increase in erythema, DNA damage and sunburn cell formation. Salicylic acid did not produce significant changes in any of these biomarkers. Conclusions Short-term topical application of glycolic acid in a cosmetic formulation increased the sensitivity of human skin to SSR, while a comparable treatment with salicylic acid did not. PMID:19411163

Allostery through protein-induced DNA bubbles

DOE PAGES

Traverso, Joseph J.; Manoranjan, Valipuram S.; Bishop, A. R.; ...

2015-03-12

Allostery through DNA is increasingly recognized as an important modulator of DNA functions. Here, we show that the coalescence of protein-induced DNA bubbles can mediate allosteric interactions that drive protein aggregation. We propose that such allostery may regulate DNA's flexibility and the assembly of the transcription machinery. Mitochondrial transcription factor A (TFAM), a dual-function protein involved in mitochondrial DNA (mtDNA) packaging and transcription initiation, is an ideal candidate to test such a hypothesis owing to its ability to locally unwind the double helix. Numerical simulations demonstrate that the coalescence of TFAM-induced bubbles can explain experimentally observed TFAM oligomerization. The resultingmore » melted DNA segment, approximately 10 base pairs long, around the joints of the oligomers act as flexible hinges, which explains the efficiency of TFAM in compacting DNA. Since mitochondrial polymerase (mitoRNAP) is involved in melting the transcription bubble, TFAM may use the same allosteric interaction to both recruit mitoRNAP and initiate transcription.« less

DNA from Porphyromonas gingivalis and Tannerella forsythia induce cytokine production in human monocytic cell lines.

PubMed

Sahingur, S E; Xia, X-J; Alamgir, S; Honma, K; Sharma, A; Schenkein, H A

2010-04-01

Toll-like receptor 9 (TLR9) expression is increased in periodontally diseased tissues compared with healthy sites indicating a possible role of TLR9 and its ligand, bacterial DNA (bDNA), in periodontal disease pathology. Here, we determine the immunostimulatory effects of periodontal bDNA in human monocytic cells (THP-1). THP-1 cells were stimulated with DNA of two putative periodontal pathogens: Porphyromonas gingivalis and Tannerella forsythia. The role of TLR9 in periodontal bDNA-initiated cytokine production was determined either by blocking TLR9 signaling in THP-1 cells with chloroquine or by measuring IL-8 production and nuclear factor-kappaB (NF-kappaB) activation in HEK293 cells stably transfected with human TLR9. Cytokine production (IL-1beta, IL-6, and TNF-alpha) was increased significantly in bDNA-stimulated cells compared with controls. Chloroquine treatment of THP-1 cells decreased cytokine production, suggesting that TLR9-mediated signaling pathways are operant in the recognition of DNA from periodontal pathogens. Compared with native HEK293 cells, TLR9-transfected cells demonstrated significantly increased IL-8 production (P < 0.001) and NF-kappaB activation in response to bDNA, further confirming the role of TLR9 in periodontal bDNA recognition. The results of PCR arrays demonstrated upregulation of proinflammatory cytokine and NF-kappaB genes in response to periodontal bDNA in THP-1 cells, suggesting that cytokine induction is through NF-kappaB activation. Hence, immune responses triggered by periodontal bacterial nucleic acids may contribute to periodontal disease pathology by inducing proinflammatory cytokine production through the TLR9 signaling pathway.

The live cell DNA stain SiR-Hoechst induces DNA damage responses and impairs cell cycle progression.

PubMed

Sen, Onur; Saurin, Adrian T; Higgins, Jonathan M G

2018-05-21

SiR-Hoechst (SiR-DNA) is a far-red fluorescent DNA probe being used widely for time-lapse imaging of living cells that is reported to be minimally toxic at concentrations as high as 10-25 µM. However, measuring nuclear import of Cyclin B1, inhibition of mitotic entry, and the induction of γH2AX foci in cultured human cells reveals that SiR-Hoechst induces DNA damage responses and G2 arrest at concentrations well below 1 µM. SiR-Hoechst is useful for live cell imaging, but it should be used with caution and at the lowest practicable concentration.

Ginsenoside C-Mx Isolated from Notoginseng Stem-leaf Ginsenosides Attenuates Ultraviolet B-mediated Photoaging in Human Dermal Fibroblasts.

PubMed

Liu, Xiao-Yi; Hwang, Eunson; Park, Bom; Ngo, Hien T T; Xiao, Yong-Kun; Yi, Tae-Hoo

2018-05-20

Notoginseng is a traditional herbal medicine widely used for medicinal therapy in Asia, as it contains numerous ginsenosides with pharmacological effects. In this study, we submitted Notoginseng stem-leaf (NGL) ginsenosides to an enzyme to create reaction the monomer products of ginsenoside C-Mx and then investigated the ability of ginsenoside C-Mx to protect the skin against ultraviolet B-induced injury in normal human dermal fibroblasts (NHDFs). Ginsenoside C-Mx alleviated UVB-induced intracellular reactive oxygen species (ROS), MMP-1, and IL-6 expression while accelerating TGF-β and procollagen type I secretion. In addition, ginsenoside C-Mx reversed UVB-induced procollagen type I reduction by regulating the TGF-β/Smad signaling pathway. Moreover, ginsenoside C-Mx inhibited activation of AP-1 transcription factor, an inducer of MMPs. Ginsenoside C-Mx displayed an outstanding antioxidant capacity, increasing expression of cytoprotective antioxidants such as HO-1 and, NQO-1 expression by enhancing the nuclear accumulation of Nrf2. Interestingly, applied of ginsenoside C-Mx treatment (1, 10, 20μM) significantly diminished UVB-induced suppressed NF-κB expression, decreasing the over-released inflammatory cytokines. Taken together, our findings indicated that ginsenoside C-Mx may act as a promising natural cosmetic ingredient for prevention and treatment of UVB-induced skin damage. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Oxidant-induced DNA damage of target cells.

PubMed Central

Schraufstätter, I; Hyslop, P A; Jackson, J H; Cochrane, C G

1988-01-01

In this study we examined the leukocytic oxidant species that induce oxidant damage of DNA in whole cells. H2O2 added extracellularly in micromolar concentrations (10-100 microM) induced DNA strand breaks in various target cells. The sensitivity of a specific target cell was inversely correlated to its catalase content and the rate of removal of H2O2 by the target cell. Oxidant species produced by xanthine oxidase/purine or phorbol myristate acetate-stimulated monocytes induced DNA breakage of target cells in proportion to the amount of H2O2 generated. These DNA strand breaks were prevented by extracellular catalase, but not by superoxide dismutase. Cytotoxic doses of HOCl, added to target cells, did not induce DNA strand breakage, and myeloperoxidase added extracellularly in the presence of an H2O2-generating system, prevented the formation of DNA strand breaks in proportion to its H2O2 degrading capacity. The studies also indicated that H2O2 formed hydroxyl radical (.OH) intracellularly, which appeared to be the most likely free radical responsible for DNA damage: .OH was detected in cells exposed to H2O2; the DNA base, deoxyguanosine, was hydroxylated in cells exposed to H2O2; and intracellular iron was essential for induction of DNA strand breaks. PMID:2843565

Perilla frutescens leaves extract ameliorates ultraviolet radiation-induced extracellular matrix damage in human dermal fibroblasts and hairless mice skin.

PubMed

Bae, Jung-Soo; Han, Mira; Shin, Hee Soon; Kim, Min-Kyoung; Shin, Chang-Yup; Lee, Dong Hun; Chung, Jin Ho

2017-01-04

Perilla frutescens (L.) Britt. (Lamiaceae) is a traditional herb that is consumed in East Asian countries as a traditional medicine. This traditional herb has been documented for centuries to treat various diseases such as depression, allergies, inflammation and asthma. However, the effect of Perilla frutescens on skin has not been characterized well. The present study aimed to investigate the effect of Perilla frutescens leaves extract (PLE) on ultraviolet radiation-induced extracellular matrix damage in human dermal fibroblasts and hairless mice skin. Human dermal fibroblasts and Skh-1 hairless mice were irradiated with UV and treated with PLE. Protein and mRNA levels of various target molecules were analyzed by western blotting and quantitative RT-PCR, respectively. Histological changes of mouse skin were analyzed by H&E staining. To elucidate underlying mechanism of PLE, activator protein-1 (AP-1) DNA binding assay and the measurement of reactive oxygen species (ROS) were performed. PLE significantly inhibited basal and UV-induced MMP-1 and MMP-3 expression dose-dependently, and also decreased UV-induced phosphorylation of extracellular signal-regulated kinases and c-Jun N-terminal kinases. This inhibitory effects of PLE on MMP-1 and MMP-3 were mediated by reduction of ROS generation and AP-1 DNA binding activity induced by UV. Furthermore, PLE promoted type I procollagen production irrespective of UV irradiation. In the UV-irradiated animal model, PLE significantly reduced epidermal skin thickness and MMP-13 expression induced by UV. Our results demonstrate that PLE has the protective effect against UV-induced dermal matrix damage. Therefore, we suggest that PLE can be a potential agent for prevention of skin aging. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Protective Effect of the Ethyl Acetate Fraction of Sargassum muticum Against Ultraviolet B–Irradiated Damage in Human Keratinocytes

PubMed Central

Piao, Mei Jing; Yoon, Weon Jong; Kang, Hee Kyoung; Yoo, Eun Sook; Koh, Young Sang; Kim, Dong Sam; Lee, Nam Ho; Hyun, Jin Won

2011-01-01

The aim of this study was to investigate the cytoprotective properties of the ethyl acetate fraction of Sargassum muticum (SME) against ultraviolet B (UVB)-induced cell damage in human keratinocytes (HaCaT cells). SME exhibited scavenging activity toward the 1,1-diphenyl-2-picrylhydrazyl radicals and hydrogen peroxide (H2O2) and UVB-induced intracellular reactive oxygen species (ROS). SME also scavenged the hydroxyl radicals generated by the Fenton reaction (FeSO4 + H2O2), which was detected using electron spin resonance spectrometry. In addition, SME decreased the level of lipid peroxidation that was increased by UVB radiation, and restored the level of protein expression and the activities of antioxidant enzymes that were decreased by UVB radiation. Furthermore, SME reduced UVB-induced apoptosis as shown by decreased DNA fragmentation and numbers of apoptotic bodies. These results suggest that SME protects human keratinocytes against UVB-induced oxidative stress by enhancing antioxidant activity in cells, thereby inhibiting apoptosis. PMID:22174656

Combined branched-DNA and conventional HBV PCR assays for detection of serum HBV-DNA in hepatitis B e antigen-positive chronic hepatitis B patients.

PubMed

Ozdarendeli, Aykut; Toroman, Zulal Asci; Bulut, Yasemin; Demirbag, Kutbeddin; Kalkan, Ahmet; Ozden, Mehmet; Kilic, Suleyman Sirri

2006-01-01

Monitoring of HBV replication level is very useful for the management of patients with chronic HBV. However, the use of the correct tools to quantify HBV-DNA levels in serum and monitor the replication of HBV is of paramount importance in terms of diagnosis, and antiviral treatment of patients with chronic HBV infection. The aim of this study was to combine the bDNA assay and HBV PCR to improve detection of viremia the patients with HBeAg-positive chronic hepatitis B infection. In this study, 67 HBeAg-positive chronic hepatitis B patients were analyzed to determine viremia level using bDNA and HBV PCR assays. Sixty-four patients with HBeAg-positive chronic hepatitis B showed positivity by conventional HBV PCR, whereas 56 subjects with HBeAg-positive chronic hepatitis B showed HBV-DNA levels by bDNA. The results indicated that it is reasonable to use the bDNA assay to determine HBV replicative activity first, and use conventional HBV-PCR for HBeAg-positive chronic hepatitis B patient samples that are negative in bDNA assay.

Channel catfish response to ultraviolet-B radiation

USGS Publications Warehouse

Ewing, M.S.; Blazer, V.S.; Fabacher, D.L.; Little, E.E.; Kocan, K.M.

1999-01-01

Fingerling channel catfish Ictalurus punctatus exposed to simulated ultraviolet-B radiation at an average daily dose of 2.9 J/cm2 were quite sensitive to the radiation. After a 24-h exposure, thinning of the most dorsal epidermis frequently was accompanied by edema. Compared with epidermis of unexposed fish, mucous cells in exposed fish were less superficial and club cells were less numerous both dorsally and high on the lateral surface of the body. Sunburn cells with pyknotic nuclei were evident in the epidermis of exposed fish. Among fish exposed for 48 h, focal necrosis and sloughing of the outer epidermal layer were widespread. A methanol-extractable skin substance that is associated with resistance to sunburn in other fish species was not detected in channel catfish.

IKK{epsilon} modulates RSV-induced NF-{kappa}B-dependent gene transcription

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bao Xiaoyong; Indukuri, Hemalatha; Liu Tianshuang

2010-12-20

Respiratory syncytial virus (RSV), a negative-strand RNA virus, is the most common cause of epidemic respiratory disease in infants and young children. RSV infection of airway epithelial cells induces the expression of immune/inflammatory genes through the activation of a subset of transcription factors, including Nuclear Factor-{kappa}B (NF-{kappa}B). In this study we have investigated the role of the non canonical I{kappa}B kinase (IKK){epsilon} in modulating RSV-induced NF-{kappa}B activation. Our results show that inhibition of IKK{epsilon} activation results in significant impairment of viral-induced NF-{kappa}B-dependent gene expression, through a reduction in NF-{kappa}B transcriptional activity, without changes in nuclear translocation or DNA-binding activity. Absencemore » of IKK{epsilon} results in a significant decrease of RSV-induced NF-{kappa}B phosphorylation on serine 536, a post-translational modification important for RSV-induced NF-{kappa}B-dependent gene expression, known to regulate NF-{kappa}B transcriptional activity without affecting nuclear translocation. This study identifies a novel mechanism by which IKK{epsilon} regulates viral-induced cellular signaling.« less

HIV DNA-Adenovirus Multiclade Envelope Vaccine Induces gp41 Antibody Immunodominance in Rhesus Macaques

PubMed Central

Williams, Wilton B.; Saunders, Kevin O.; Seaton, Kelly E.; Wiehe, Kevin J.; Vandergrift, Nathan; Von Holle, Tarra A.; Trama, Ashley M.; Parks, Robert J.; Luo, Kan; Gurley, Thaddeus C.; Kepler, Thomas B.; Marshall, Dawn J.; Montefiori, David C.; Sutherland, Laura L.; Alam, Munir S.; Whitesides, John F.; Bowman, Cindy M.; Permar, Sallie R.; Graham, Barney S.; Mascola, John R.; Seed, Patrick C.; Van Rompay, Koen K. A.; Tomaras, Georgia D.; Moody, M. Anthony

2017-01-01

ABSTRACT Dominant antibody responses in vaccinees who received the HIV-1 multiclade (A, B, and C) envelope (Env) DNA/recombinant adenovirus virus type 5 (rAd5) vaccine studied in HIV-1 Vaccine Trials Network (HVTN) efficacy trial 505 (HVTN 505) targeted Env gp41 and cross-reacted with microbial antigens. In this study, we asked if the DNA/rAd5 vaccine induced a similar antibody response in rhesus macaques (RMs), which are commonly used as an animal model for human HIV-1 infections and for testing candidate HIV-1 vaccines. We also asked if gp41 immunodominance could be avoided by immunization of neonatal RMs during the early stages of microbial colonization. We found that the DNA/rAd5 vaccine elicited a higher frequency of gp41-reactive memory B cells than gp120-memory B cells in adult and neonatal RMs. Analysis of the vaccine-induced Env-reactive B cell repertoire revealed that the majority of HIV-1 Env-reactive antibodies in both adult and neonatal RMs were targeted to gp41. Interestingly, a subset of gp41-reactive antibodies isolated from RMs cross-reacted with host antigens, including autologous intestinal microbiota. Thus, gp41-containing DNA/rAd5 vaccine induced dominant gp41-microbiota cross-reactive antibodies derived from blood memory B cells in RMs as observed in the HVTN 505 vaccine efficacy trial. These data demonstrated that RMs can be used to investigate gp41 immunodominance in candidate HIV-1 vaccines. Moreover, colonization of neonatal RMs occurred within the first week of life, and immunization of neonatal RMs during this time also induced a dominant gp41-reactive antibody response. IMPORTANCE Our results are critical to current work in the HIV-1 vaccine field evaluating the phenomenon of gp41 immunodominance induced by HIV-1 Env gp140 in RMs and humans. Our data demonstrate that RMs are an appropriate animal model to study this phenomenon and to determine the immunogenicity in new HIV-1 Env trimer vaccine designs. The demonstration of gp41

The effects of ultraviolet-B radiation on freshwater invertebrates: Experiments with a solar simulator

USGS Publications Warehouse

Hurtubise, R.D.; Havel, J.E.; Little, E.E.

1998-01-01

There is concern that decreases in stratospheric ozone will lead to hazardous levels of ultraviolet-B (UV-B) radiation at the Earth's surface. In clear water, UV-B may penetrate to significant depths. The purpose of the current study was to compare the sensitivity of freshwater invertebrates to UV-B. We used a solar simulator, calibrated to match local ambient solar radiation, to expose five species of freshwater invertebrates to enhanced levels of UV-B radiation. UV-B measurements in a eutrophic pond revealed that 10% of the irradiance penetrated to 30-cm depth and 1% to 57-cm depth. The irradiance at the upper 5-20 cm was comparable to levels used in the simulator. Median lethal dose (LD50) values were determined for the cladocerans Ceriodaphnia reticulata, Scapholeberis kingii (two induced color morphs), and Daphnia magna; the ostracod Cyprinotus incongruens; and the amphipod Hyalella azteca. Among the species, 96-h LD50 estimates were quite variable, ranging from 4.2 to 84.0 ??W cm-2. These estimates indicated S. kingii to be highly sensitive and H. azteca, C. reticulata, and D. magna to be moderately sensitive, whereas the ostracod C. incongruens was very tolerant to UV-B radiation. Overall, this study suggests that, in shallow ponds without physical refuges, UV-B radiation would have the strongest effects upon cladocerans and amphipods occurring in the water column, whereas ostracods would be better protected.

Structural basis of DNA target recognition by the B3 domain of Arabidopsis epigenome reader VAL1

PubMed Central

Sasnauskas, Giedrius; Kauneckaitė, Kotryna; Siksnys, Virginijus

2018-01-01

Abstract Arabidopsis thaliana requires a prolonged period of cold exposure during winter to initiate flowering in a process termed vernalization. Exposure to cold induces epigenetic silencing of the FLOWERING LOCUS C (FLC) gene by Polycomb group (PcG) proteins. A key role in this epigenetic switch is played by transcriptional repressors VAL1 and VAL2, which specifically recognize Sph/RY DNA sequences within FLC via B3 DNA binding domains, and mediate recruitment of PcG silencing machinery. To understand the structural mechanism of site-specific DNA recognition by VAL1, we have solved the crystal structure of VAL1 B3 domain (VAL1-B3) bound to a 12 bp oligoduplex containing the canonical Sph/RY DNA sequence 5′-CATGCA-3′/5′-TGCATG-3′. We find that VAL1-B3 makes H-bonds and van der Waals contacts to DNA bases of all six positions of the canonical Sph/RY element. In agreement with the structure, in vitro DNA binding studies show that VAL1-B3 does not tolerate substitutions at any position of the 5′-TGCATG-3′ sequence. The VAL1-B3–DNA structure presented here provides a structural model for understanding the specificity of plant B3 domains interacting with the Sph/RY and other DNA sequences. PMID:29660015

DNA adducts induced by in vitro activation of extracts of diesel and biodiesel exhaust particles.

PubMed

Ross, Jeffrey A; Nelson, Garret B; Mutlu, Esra; Warren, Sarah H; Gilmour, M Ian; DeMarini, David M

2015-01-01

Biodiesel and biodiesel-blend fuels offer a renewable alternative to petroleum diesel, but few data are available concerning the carcinogenic potential of biodiesel exhausts. We compared the formation of covalent DNA adducts by the in vitro metabolic activation of organic extracts of diesel-exhaust particles (DEP) from petroleum diesel and soy biodiesel and correlated DNA adduct levels and mutagenicity in Salmonella TA100. We examined two different DEP from petroleum diesel (C-DEP and B0), one from soy bean oil biodiesel (B100) and one from combustion of a blend of 20% B100 and 80% B0 (B20) for in vitro DNA adduct-forming potential under oxidative or nitroreductive conditions in the presence of calf thymus DNA as well as in vivo in Salmonella TA100. The modified DNA was hydrolyzed and analyzed by (32)P-postlabeling using either butanol extraction or nuclease P1 pre-enrichment. Multiple DNA adducts were produced with chromatographic mobilities consistent with PAH and nitro-PAH adducts. The types and quantities of DNA adducts produced by the two independent petroleum diesel DEP were similar, with both polycyclic aromatic hydrocarbon (PAH)- and nitro-PAH-derived adducts formed. Relative potencies for S9-mediated DNA adduct formation, either per mass of particulate or per MJ(th) energy consumed were B100 > B0 > B20. Soy biodiesel emissions induced DNA damage in the form of presumptive PAH and nitro-PAH DNA adducts that correlated with mutagenicity in Salmonella. B20 is the soy biodiesel used most commonly in the US, and it produced the lowest DNA adduct-emission factor, ∼50% that of petroleum diesel.

WRNIP1 functions upstream of DNA polymerase η in the UV-induced DNA damage response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshimura, Akari, E-mail: akari_yo@stu.musashino-u.ac.jp; Kobayashi, Yume; Tada, Shusuke

2014-09-12

Highlights: • The UV sensitivity of POLH{sup −/−} cells was suppressed by disruption of WRNIP1. • In WRNIP1{sup −/−/−}/POLH{sup −/−} cells, mutation frequencies and SCE after irradiation reduced. • WRNIP1 defect recovered rate of fork progression after irradiation in POLH{sup −/−} cells. • WRNIP1 functions upstream of Polη in the translesion DNA synthesis pathway. - Abstract: WRNIP1 (WRN-interacting protein 1) was first identified as a factor that interacts with WRN, the protein that is defective in Werner syndrome (WS). WRNIP1 associates with DNA polymerase η (Polη), but the biological significance of this interaction remains unknown. In this study, we analyzedmore » the functional interaction between WRNIP1 and Polη by generating knockouts of both genes in DT40 chicken cells. Disruption of WRNIP1 in Polη-disrupted (POLH{sup −/−}) cells suppressed the phenotypes associated with the loss of Polη: sensitivity to ultraviolet light (UV), delayed repair of cyclobutane pyrimidine dimers (CPD), elevated frequency of mutation, elevated levels of UV-induced sister chromatid exchange (SCE), and reduced rate of fork progression after UV irradiation. These results suggest that WRNIP1 functions upstream of Polη in the response to UV irradiation.« less

Ultraviolet-radiation-induced inflammation promotes angiotropism and metastasis in melanoma

NASA Astrophysics Data System (ADS)

Bald, Tobias; Quast, Thomas; Landsberg, Jennifer; Rogava, Meri; Glodde, Nicole; Lopez-Ramos, Dorys; Kohlmeyer, Judith; Riesenberg, Stefanie; van den Boorn-Konijnenberg, Debby; Hömig-Hölzel, Cornelia; Reuten, Raphael; Schadow, Benjamin; Weighardt, Heike; Wenzel, Daniela; Helfrich, Iris; Schadendorf, Dirk; Bloch, Wilhelm; Bianchi, Marco E.; Lugassy, Claire; Barnhill, Raymond L.; Koch, Manuel; Fleischmann, Bernd K.; Förster, Irmgard; Kastenmüller, Wolfgang; Kolanus, Waldemar; Hölzel, Michael; Gaffal, Evelyn; Tüting, Thomas

2014-03-01

Intermittent intense ultraviolet (UV) exposure represents an important aetiological factor in the development of malignant melanoma. The ability of UV radiation to cause tumour-initiating DNA mutations in melanocytes is now firmly established, but how the microenvironmental effects of UV radiation influence melanoma pathogenesis is not fully understood. Here we report that repetitive UV exposure of primary cutaneous melanomas in a genetically engineered mouse model promotes metastatic progression, independent of its tumour-initiating effects. UV irradiation enhanced the expansion of tumour cells along abluminal blood vessel surfaces and increased the number of lung metastases. This effect depended on the recruitment and activation of neutrophils, initiated by the release of high mobility group box 1 (HMGB1) from UV-damaged epidermal keratinocytes and driven by Toll-like receptor 4 (TLR4). The UV-induced neutrophilic inflammatory response stimulated angiogenesis and promoted the ability of melanoma cells to migrate towards endothelial cells and use selective motility cues on their surfaces. Our results not only reveal how UV irradiation of epidermal keratinocytes is sensed by the innate immune system, but also show that the resulting inflammatory response catalyses reciprocal melanoma-endothelial cell interactions leading to perivascular invasion, a phenomenon originally described as angiotropism in human melanomas by histopathologists. Angiotropism represents a hitherto underappreciated mechanism of metastasis that also increases the likelihood of intravasation and haematogenous dissemination. Consistent with our findings, ulcerated primary human melanomas with abundant neutrophils and reactive angiogenesis frequently show angiotropism and a high risk for metastases. Our work indicates that targeting the inflammation-induced phenotypic plasticity of melanoma cells and their association with endothelial cells represent rational strategies to specifically interfere

Characterization of the human SNM1A and SNM1B/Apollo DNA repair exonucleases.

PubMed

Sengerová, Blanka; Allerston, Charles K; Abu, Mika; Lee, Sook Y; Hartley, Janet; Kiakos, Konstantinos; Schofield, Christopher J; Hartley, John A; Gileadi, Opher; McHugh, Peter J

2012-07-27

Human SNM1A and SNM1B/Apollo have both been implicated in the repair of DNA interstrand cross-links (ICLs) by cellular studies, and SNM1B is also required for telomere protection. Here, we describe studies on the biochemical characterization of the SNM1A and SNM1B proteins. The results reveal some fundamental differences in the mechanisms of the two proteins. Both SNM1A and SNM1B digest double-stranded and single-stranded DNA with a 5'-to-3' directionality in a reaction that is stimulated by divalent cations, and both nucleases are inhibited by the zinc chelator o-phenanthroline. We find that SNM1A has greater affinity for single-stranded DNA over double-stranded DNA that is not observed with SNM1B. Although both proteins demonstrate a low level of processivity on low molecular weight DNA oligonucleotide substrates, when presented with high molecular weight DNA, SNM1A alone is rendered much more active, being capable of digesting kilobase-long stretches of DNA. Both proteins can digest past ICLs induced by the non-distorting minor groove cross-linking agent SJG-136, albeit with SNM1A showing a greater capacity to achieve this. This is consistent with the proposal that SNM1A and SNM1B might exhibit some redundancy in ICL repair. Together, our work establishes differences in the substrate selectivities of SNM1A and SNM1B that are likely to be relevant to their in vivo roles and which might be exploited in the development of selective inhibitors.

Black soybean seed coat polyphenols prevent B(a)P-induced DNA damage through modulating drug-metabolizing enzymes in HepG2 cells and ICR mice.

PubMed

Zhang, Tianshun; Jiang, Songyan; He, Chao; Kimura, Yuki; Yamashita, Yoko; Ashida, Hitoshi

2013-04-15

Black soybean seed coat is a rich source of polyphenols that have been reported to have various physiological functions. The present study investigated the potential protective effects of polyphenolic extracts from black soybean seed coat on DNA damage in human hepatoma HepG2 cells and ICR mice. The results from micronucleus (MN) assay revealed that black soybean seed coat extract (BE) at concentrations up to 25μg/mL was non-genotoxic. It is noteworthy that BE (at 4.85μg/mL) and its main components, procyanidins (PCs) and cyanidin 3-glucoside (C3G), at 10μM significantly reduced the genotoxic effect induced by benzo[a]pyrene [B(a)P]. To obtain insights into the underlying mechanism, we investigated BE and its main components on drug-metabolizing enzyme expression. The results of this study demonstrate that BE and its main components, PCs and C3G, down-regulated B(a)P-induced cytochrome P4501A1 (CYP1A1) expression by inhibiting the transformation of aryl hydrocarbon receptor. Moreover, they increased expression of detoxifying defense enzymes, glutathione S-transferases (GSTs) via increasing the binding of nuclear factor-erythroid-2-related factor 2 to antioxidant response elements. Collectively, we found that PCs and C3G, which are the main active compounds of BE, down-regulated CYP1A1 and up-regulated GST expression to protect B(a)P-induced DNA damage in HepG2 cells and ICR mice effectively. Copyright © 2013 Elsevier B.V. All rights reserved.

Analysis of nicotine-induced DNA damage in cells of the human respiratory tract.

PubMed

Ginzkey, Christian; Stueber, Thomas; Friehs, Gudrun; Koehler, Christian; Hackenberg, Stephan; Richter, Elmar; Hagen, Rudolf; Kleinsasser, Norbert H

2012-01-05

Epithelium of the upper and lower airways is a common origin of tobacco-related cancer. The main tobacco alkaloid nicotine may be associated with tumor progression. The potential of nicotine in inducing DNA mutations as a step towards cancer initiation is still controversially discussed. Different subtypes of nicotinic acetylcholine receptors (nAChR) are expressed in human nasal mucosa and a human bronchial cell line representing respiratory mucosa as a possible target for receptor-mediated pathways. In the present study, both cell systems were investigated with respect to DNA damage induced by nicotine and its mechanisms. Specimens of human nasal mucosa were harvested during surgery of the nasal air passage. After enzymatic digestion over night, single cells were exposed to an increasing nicotine concentration between 0.001 mM and 4.0mM. In a second step co-incubation was performed using the antioxidant N-acetylcysteine (NAC) and the nAChR antagonist mecamylamine. DNA damage was assessed using the alkali version of the comet assay. Dose finding experiments for mecamylamine to evaluate the maximal inhibitory effect were performed in the human bronchial cell line BEAS-2B with an increasing mecamylamine concentration and a constant nicotine concentration. The influence of nicotine in the apoptotic pathway was evaluated in BEAS-2B cells with the TUNEL assay combined with flow cytometry. After 1h of nicotine exposure with 0.001, 0.01, 0.1, 1.0 and 4.0mM, significant DNA damage was determined at 1.0mM. Further co-incubation experiments with mecamylamine and NAC were performed using 1.0mM of nicotine. The strongest inhibitory effect was measured at 1.0mM mecamylamine and this concentration was used for co-incubation. Both, the antioxidant NAC at a concentration of 1.0mM, based on the literature, as well as the receptor antagonist were capable of complete inhibition of the nicotine-induced DNA migration in the comet assay. A nicotine-induced increase or decrease in

Oxidatively-induced DNA damage and base excision repair in euthymic patients with bipolar disorder.

PubMed

Ceylan, Deniz; Tuna, Gamze; Kirkali, Güldal; Tunca, Zeliha; Can, Güneş; Arat, Hidayet Ece; Kant, Melis; Dizdaroglu, Miral; Özerdem, Ayşegül

2018-05-01

Oxidatively-induced DNA damage has previously been associated with bipolar disorder. More recently, impairments in DNA repair mechanisms have also been reported. We aimed to investigate oxidatively-induced DNA lesions and expression of DNA glycosylases involved in base excision repair in euthymic patients with bipolar disorder compared to healthy individuals. DNA base lesions including both base and nucleoside modifications were measured using gas chromatography-tandem mass spectrometry and liquid chromatography-tandem mass spectrometry with isotope-dilution in DNA samples isolated from leukocytes of euthymic patients with bipolar disorder (n = 32) and healthy individuals (n = 51). The expression of DNA repair enzymes OGG1 and NEIL1 were measured using quantitative real-time polymerase chain reaction. The levels of malondialdehyde were measured using high performance liquid chromatography. Seven DNA base lesions in DNA of leukocytes of patients and healthy individuals were identified and quantified. Three of them had significantly elevated levels in bipolar patients when compared to healthy individuals. No elevation of lipid peroxidation marker malondialdehyde was observed. The level of OGG1 expression was significantly reduced in bipolar patients compared to healthy individuals, whereas the two groups exhibited similar levels of NEIL1 expression. Our results suggest that oxidatively-induced DNA damage occurs and base excision repair capacity may be decreased in bipolar patients when compared to healthy individuals. Measurement of oxidatively-induced DNA base lesions and the expression of DNA repair enzymes may be of great importance for large scale basic research and clinical studies of bipolar disorder. Copyright © 2018 Elsevier B.V. All rights reserved.

Quantifying the effects of corn growth and physiological responses to Ultraviolet-B radiation for modeling

USDA-ARS?s Scientific Manuscript database

To understand the consequences of rising levels of Ultraviolet-B (UV-B) radiation on maize (Zea mays L.), two experiments were conducted using sunlit plant growth chambers at a wide range UV-B radiation. Maize cultivars Terral-2100 and DKC 65-44 were grown in 2003 and 2008, respectively, at four le...

DNA sequences, recombinant DNA molecules and processes for producing the A and B subunits of cholera toxin and preparations containing so-obtained subunit or subunits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harford, N.; De Wilde, M.

1987-05-19

A recombinant DNA molecule is described comprising at least a portion coding for subunits A and B of cholera toxin, or a fragment or derivative of the portion wherein the fragment or derivative codes for a polypeptide have an activity which can induce an immune response to subunit A; can induce an immune response to subunit A and cause epithelial cell penetration and the enzymatic effect leading to net loss of fluid into the gut lumen; can bind to the membrane receptor for the B subunit of cholera toxin; can induce an immune response to subunit B; can induce anmore » immune response to subunit B and bind to the membrane receptor; or has a combination of the activities.« less

Increased resistance to ionizing and ultraviolet radiation in Escherichia coli JM83 is associated with a chromosomal rearrangement.

PubMed

McLean, K M; Gutman, P D; Minton, K W; Clark, E P

1992-06-01

Cells cope with radiation damage through several mechanisms: (1) increased DNA repair activity, (2) scavenging and inactivation of radiation-induced radical molecules, and (3) entry into a G0-like quiescent state. We have investigated a chromosomal rearrangement to elucidate further the molecular and genetic mechanisms underlying these phenomena. A mutant of Escherichia coli JM83 (phi 80dlacZ delta M15) was isolated that demonstrated significantly increased resistance to both ionizing and ultraviolet radiation. Surviving fractions of mutant and wild-type cells were measured following exposure to standardized doses of radiation. Increased radioresistance was directly related to a chromosomal alteration near the bacteriophage phi 80 attachment site (attB), as initially detected by the LacZ- phenotype of the isolate. Southern hybridization of chromosomal DNA from the mutant and wild-type E. coli JM83 strains indicated that a deletion had occurred. We propose that the deletion near the attB locus produces the radioresistant phenotype of the E. coli JM83 LacZ- mutant, perhaps through the alteration or inactivation of a gene or its controlling element(s).

Transcription-induced DNA supercoiling: New roles of intranucleosomal DNA loops in DNA repair and transcription.

PubMed

Gerasimova, N S; Pestov, N A; Kulaeva, O I; Clark, D J; Studitsky, V M

2016-05-26

RNA polymerase II (Pol II) transcription through chromatin is accompanied by formation of small intranucleosomal DNA loops. Pol II captured within a small loop drives accumulation of DNA supercoiling, facilitating further transcription. DNA breaks relieve supercoiling and induce Pol II arrest, allowing detection of DNA damage hidden in chromatin structure.

Solar ultraviolet radiation induces biological alterations in human skin in vitro: relevance of a well-balanced UVA/UVB protection.

PubMed

Bernerd, Francoise; Marionnet, Claire; Duval, Christine

2012-06-01

Cutaneous damages such as sunburn, pigmentation, and photoaging are known to be induced by acute as well as repetitive sun exposure. Not only for basic research, but also for the design of the most efficient photoprotection, it is crucial to understand and identify the early biological events occurring after ultraviolet (UV) exposure. Reconstructed human skin models provide excellent and reliable in vitro tools to study the UV-induced alterations of the different skin cell types, keratinocytes, fibroblasts, and melanocytes in a dose- and time-dependent manner. Using different in vitro human skin models, the effects of UV light (UVB and UVA) were investigated. UVB-induced damages are essentially epidermal, with the typical sunburn cells and DNA lesions, whereas UVA radiation-induced damages are mostly located within the dermal compartment. Pigmentation can also be obtained after solar simulated radiation exposure of pigmented reconstructed skin model. Those models are also highly adequate to assess the potential of sunscreens to protect the skin from UV-associated damage, sunburn reaction, photoaging, and pigmentation. The results showed that an effective photoprotection is provided by broad-spectrum sunscreens with a potent absorption in both UVB and UVA ranges.

Myeloperoxidase-induced Genomic DNA-centered Radicals*

PubMed Central

Gomez-Mejiba, Sandra E.; Zhai, Zili; Gimenez, Maria S.; Ashby, Michael T.; Chilakapati, Jaya; Kitchin, Kirk; Mason, Ronald P.; Ramirez, Dario C.

2010-01-01

Myeloperoxidase (MPO) released by activated neutrophils can initiate and promote carcinogenesis. MPO produces hypochlorous acid (HOCl) that oxidizes the genomic DNA in inflammatory cells as well as in surrounding epithelial cells. DNA-centered radicals are early intermediates formed during DNA oxidation. Once formed, DNA-centered radicals decay by mechanisms that are not completely understood, producing a number of oxidation products that are studied as markers of DNA oxidation. In this study we employed the 5,5-dimethyl-1-pyrroline N-oxide-based immuno-spin trapping technique to investigate the MPO-triggered formation of DNA-centered radicals in inflammatory and epithelial cells and to test whether resveratrol blocks HOCl-induced DNA-centered radical formation in these cells. We found that HOCl added exogenously or generated intracellularly by MPO that has been taken up by the cell or by MPO newly synthesized produces DNA-centered radicals inside cells. We also found that resveratrol passed across cell membranes and scavenged HOCl before it reacted with the genomic DNA, thus blocking DNA-centered radical formation. Taken together our results indicate that the formation of DNA-centered radicals by intracellular MPO may be a useful point of therapeutic intervention in inflammation-induced carcinogenesis. PMID:20406811

Inducible error-prone repair in B. subtilis. Final report, September 1, 1979-June 30, 1981

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yasbin, R. E.

1981-06-01

The research performed under this contract has been concentrated on the relationship between inducible DNA repair systems, mutagenesis and the competent state in the gram positive bacterium Bacillus subtilis. The following results have been obtained from this research: (1) competent Bacillus subtilis cells have been developed into a sensitive tester system for carcinogens; (2) competent B. subtilis cells have an efficient excision-repair system, however, this system will not function on bacteriophage DNA taken into the cell via the process of transfection; (3) DNA polymerase III is essential in the mechanism of the process of W-reactivation; (4) B. subtilis strains curedmore » of their defective prophages have been isolated and are now being developed for gene cloning systems; (5) protoplasts of B. subtilis have been shown capable of acquiring DNA repair enzymes (i.e., enzyme therapy); and (6) a plasmid was characterized which enhanced inducible error-prone repair in a gram positive organism.« less

The Human DNA glycosylases NEIL1 and NEIL3 Excise Psoralen-Induced DNA-DNA Cross-Links in a Four-Stranded DNA Structure.

PubMed

Martin, Peter R; Couvé, Sophie; Zutterling, Caroline; Albelazi, Mustafa S; Groisman, Regina; Matkarimov, Bakhyt T; Parsons, Jason L; Elder, Rhoderick H; Saparbaev, Murat K

2017-12-12

Interstrand cross-links (ICLs) are highly cytotoxic DNA lesions that block DNA replication and transcription by preventing strand separation. Previously, we demonstrated that the bacterial and human DNA glycosylases Nei and NEIL1 excise unhooked psoralen-derived ICLs in three-stranded DNA via hydrolysis of the glycosidic bond between the crosslinked base and deoxyribose sugar. Furthermore, NEIL3 from Xenopus laevis has been shown to cleave psoralen- and abasic site-induced ICLs in Xenopus egg extracts. Here we report that human NEIL3 cleaves psoralen-induced DNA-DNA cross-links in three-stranded and four-stranded DNA substrates to generate unhooked DNA fragments containing either an abasic site or a psoralen-thymine monoadduct. Furthermore, while Nei and NEIL1 also cleave a psoralen-induced four-stranded DNA substrate to generate two unhooked DNA duplexes with a nick, NEIL3 targets both DNA strands in the ICL without generating single-strand breaks. The DNA substrate specificities of these Nei-like enzymes imply the occurrence of long uninterrupted three- and four-stranded crosslinked DNA-DNA structures that may originate in vivo from DNA replication fork bypass of an ICL. In conclusion, the Nei-like DNA glycosylases unhook psoralen-derived ICLs in various DNA structures via a genuine repair mechanism in which complex DNA lesions can be removed without generation of highly toxic double-strand breaks.

Transcription-induced DNA supercoiling: New roles of intranucleosomal DNA loops in DNA repair and transcription

PubMed Central

Gerasimova, N. S.; Pestov, N. A.; Kulaeva, O. I.; Clark, D. J.; Studitsky, V. M.

2016-01-01

ABSTRACT RNA polymerase II (Pol II) transcription through chromatin is accompanied by formation of small intranucleosomal DNA loops. Pol II captured within a small loop drives accumulation of DNA supercoiling, facilitating further transcription. DNA breaks relieve supercoiling and induce Pol II arrest, allowing detection of DNA damage hidden in chromatin structure. PMID:27115204

Spent coffee ground extract suppresses ultraviolet B-induced photoaging in hairless mice.

PubMed

Choi, Hyeon-Son; Park, Eu Ddeum; Park, Yooheon; Suh, Hyung Joo

2015-12-01

The aim of this study is to evaluate the effect of spent coffee ground (SCG) ethanol extract on UVB-induced skin aging in hairless mice. An ethanol extract of SCG (ESCG) was prepared using the residue remaining after extraction of oil from roasted SCG. High performance liquid chromatography (HPLC) analysis showed that the content of caffeine (41.58 ± 0.54 μg/mg) was higher than that of chlorogenic acid isomers (~9.17 μg/mg) in ESCG. ESCG significantly decreased the UVB-induced intracellular reactive oxygen species in HaCaT cells. UVB-induced wrinkle formation in mice dorsal skin was effectively reduced by ESCG administration; high dose of ESCG (5 g/L) caused the reduction of wrinkle area by 30% compared with UVB-treated control (UVBC). This result correlated with the ESCG-mediated decrease in epidermis thickness (25%). In addition, ESCG administration significantly reduced transdermal water loss (20%) and erythema formation (35%) derived from UVB exposure. Collagen type I (COL-1) level in dorsal skin was effectively recovered by ESCG administration. These results were supported by down-regulation of collagen-degrading matrix metalloproteinase 2 (MMP2) and 9 (MMP9) expressions. Our results indicate that ESCG protects mouse skin from UVB-induced photoaging by suppressing the expression of matrix metalloproteinases. Our study suggests that ESCG may be anti-photoaging agent. Copyright © 2015 Elsevier B.V. All rights reserved.

Home versus outpatient ultraviolet B phototherapy for mild to severe psoriasis: pragmatic multicentre randomised controlled non-inferiority trial (PLUTO study).

PubMed

Koek, Mayke B G; Buskens, Erik; van Weelden, Huib; Steegmans, Paul H A; Bruijnzeel-Koomen, Carla A F M; Sigurdsson, Vigfús

2009-05-07

To determine whether ultraviolet B phototherapy at home is equally safe and equally effective as ultraviolet B phototherapy in an outpatient setting for patients with psoriasis. Pragmatic multicentre single blind randomised clinical trial (PLUTO study). Dermatology departments of 14 hospitals in the Netherlands. 196 patients with psoriasis who were clinically eligible for narrowband (TL-01) ultraviolet B phototherapy. The first 105 consecutive patients were also followed for one year after therapy. Ultraviolet B phototherapy at home using a TL-01 home phototherapy unit compared with standard narrowband ultraviolet B phototherapy in an outpatient setting. Both therapies were done in a setting reflecting routine daily practice in the Netherlands. The main outcome measure was effectiveness as measured by the proportion of patients with a 50% or more reduction of the baseline psoriasis area and severity index (PASI) or self administered psoriasis area and severity index (SAPASI), called the PASI 50 and SAPASI 50 (relevant treatment effect). Another outcome of effectiveness was the percentage reduction in median scores on the PASI as well as SAPASI. Also the proportions of patients reaching the PASI 75 and SAPASI 75 (successful treatment effect), and the PASI 90 and SAPASI 90 (almost complete clearance) were calculated. Other secondary outcomes were quality of life (SF-36, psoriasis disability index), burden of treatment (questionnaire), patients' preferences and satisfaction (questionnaire), and dosimetry and short term side effects (diary). 82% of the patients treated at home compared with 79% of the patients treated in an outpatient setting reached the SAPASI 50 (difference 2.8%, 95% confidence interval -8.6% to 14.2%), and 70% compared with 73% reached the PASI 50 (-2.3%, -15.7% to 11.1%). For patients treated at home the median SAPASI score decreased 82% (from 6.7 to 1.2) and the median PASI score decreased 74% (from 8.4 to 2.2), compared with 79% (from 7.0 to 1

Efficacy of PLGA-loaded apigenin nanoparticles in Benzo[a]pyrene and ultraviolet-B induced skin cancer of mice: mitochondria mediated apoptotic signalling cascades.

PubMed

Das, Sreemanti; Das, Jayeeta; Samadder, Asmita; Paul, Avijit; Khuda-Bukhsh, Anisur Rahman

2013-12-01

Skin cancer is increasing at an alarming rate and becoming resistant to conventional chemotherapy necessitating improved drug delivery system. We loaded apigenin (Ap), a dietary flavonoid having anti-cancer property, with poly (lactic-co-glycolide) (PLGA) nanoparticles (NAp) to explore if nano-encapsulation could enhance anti-carcinogenic effect against ultra-violet B (UVB) and Benzo(a)pyrene (BaP) induced skin tumor and mitochondrial dysfunction in mice. Particle size, morphology and zeta potential of NAp were determined using dynamic light scattering and atomic force microscopy. Tumor incidence and multiplicity in UVB-BaP induced mice with/without NAp treatment were ascertained and their histolopathological sections and chromosomal aberrations were studied. ROS accumulation and mitochondrial functioning through relevant markers like mitochondrial transmembrane potential were analyzed. Mitochondrial volume changes/swelling, cytochrome c (cyt c) release, mRNA and protein expressions of Apaf-1, bax, bcl-2, cyt c, cleaved caspase-9 and 3 were studied. Results showed that NAp produced better effects than Ap, due to their smaller size, and faster mobility. NAp reduced tissue damage and frequency of chromosomal aberrations, increased ROS accumulation to mediate mitochondrial-apoptosis through modulation of several apoptotic markers and mitochondrial matrix swelling. NAp showed ameliorative potentials in combating skin cancer and therefore has greater prospect of use in therapeutic management of skin cancer. Copyright © 2013 Elsevier Ltd. All rights reserved.

Spectral classification with the International Ultraviolet Explorer: An atlas of B-type spectra

NASA Technical Reports Server (NTRS)

Rountree, Janet; Sonneborn, George

1993-01-01

New criteria for the spectral classification of B stars in the ultraviolet show that photospheric absorption lines in the 1200-1900A wavelength region can be used to classify the spectra of B-type dwarfs, subgiants, and giants on a 2-D system consistent with the optical MK system. This atlas illustrates a large number of such spectra at the scale used for classification. These spectra provide a dense matrix of standard stars, and also show the effects of rapid stellar rotation and stellar winds on the spectra and their classification. The observational material consists of high-dispersion spectra from the International Ultraviolet Explorer archives, resampled to a resolution of 0.25 A, uniformly normalized, and plotted at 10 A/cm. The atlas should be useful for the classification of other IUE high-dispersion spectra, especially for stars that have not been observed in the optical.

Generation of novel covalent RNA-protein complexes in cells by ultraviolet B irradiation: implications for autoimmunity.

PubMed

Andrade, Felipe; Casciola-Rosen, Livia A; Rosen, Antony

2005-04-01

To determine whether ultraviolet B (UVB) irradiation induces novel modifications in autoantigens targeted during experimental photoinduced epidermal damage. To search for novel UVB-induced autoantigen modifications, lysates made from UVB-irradiated human keratinocytes or HeLa cells were immunoblotted using human autoantibodies that recognize ribonucleoprotein autoantigens. Novel autoantigen structures identified were further characterized using nucleases and RNA hybridization. Human sera that recognize U1-70 kd (U1-70K) and La by immunoblotting also recognized multiple novel species when they were used to immunoblot lysates of UVB-irradiated keratinocytes or HeLa cells. These species were not present in control cells and were not observed when apoptosis was induced by Fas ligation or cytotoxic lymphocyte granule contents. Biochemical analysis using multiple assays revealed that these novel UVB-induced molecular species result from the covalent crosslinking between the U1 RNA and the hYRNA molecules with their associated proteins, including U1-70K, La, and likely components of the Sm particle. These data demonstrate that UVB irradiation of live cells can directly induce covalent RNA-protein complexes, which are recognized by human autoantibodies. As previously described for other autoantigens, these covalent complexes of RNA and proteins may have important consequences in terms of antigen capture and processing.

Parvovirus infection-induced DNA damage response

PubMed Central

Luo, Yong; Qiu, Jianming

2014-01-01

Parvoviruses are a group of small DNA viruses with ssDNA genomes flanked by two inverted terminal structures. Due to a limited genetic resource they require host cellular factors and sometimes a helper virus for efficient viral replication. Recent studies have shown that parvoviruses interact with the DNA damage machinery, which has a significant impact on the life cycle of the virus as well as the fate of infected cells. In addition, due to special DNA structures of the viral genomes, parvoviruses are useful tools for the study of the molecular mechanisms underlying viral infection-induced DNA damage response (DDR). This review aims to summarize recent advances in parvovirus-induced DDR, with a focus on the diverse DDR pathways triggered by different parvoviruses and the consequences of DDR on the viral life cycle as well as the fate of infected cells. PMID:25429305

DNA Damage Induced Neuronal Death

DTIC Science & Technology

1999-10-01

heterozygous for the DNA repair genes Os-methylguanine methyltransferase (Mgmt), 3-methyladenine DNA glycosylase (Aag) , and xeroderma pigmentosum ...mice by human 06-alkylguanine-DNA alkyltransferase. Science 1993; 259: 219-222. 4. Enokido Y, Inamura N, Araki T, et al: Loss of the xeroderma ... pigmentosum group A gene (XPA) enhances apoptosis of cultured cerebellar neurons induced by UV but not by low-K+ medium. J Neurochem 199; 69: 246-251. 5

Characterization of the Human SNM1A and SNM1B/Apollo DNA Repair Exonucleases*

PubMed Central

Sengerová, Blanka; Allerston, Charles K.; Abu, Mika; Lee, Sook Y.; Hartley, Janet; Kiakos, Konstantinos; Schofield, Christopher J.; Hartley, John A.; Gileadi, Opher; McHugh, Peter J.

2012-01-01

Human SNM1A and SNM1B/Apollo have both been implicated in the repair of DNA interstrand cross-links (ICLs) by cellular studies, and SNM1B is also required for telomere protection. Here, we describe studies on the biochemical characterization of the SNM1A and SNM1B proteins. The results reveal some fundamental differences in the mechanisms of the two proteins. Both SNM1A and SNM1B digest double-stranded and single-stranded DNA with a 5′-to-3′ directionality in a reaction that is stimulated by divalent cations, and both nucleases are inhibited by the zinc chelator o-phenanthroline. We find that SNM1A has greater affinity for single-stranded DNA over double-stranded DNA that is not observed with SNM1B. Although both proteins demonstrate a low level of processivity on low molecular weight DNA oligonucleotide substrates, when presented with high molecular weight DNA, SNM1A alone is rendered much more active, being capable of digesting kilobase-long stretches of DNA. Both proteins can digest past ICLs induced by the non-distorting minor groove cross-linking agent SJG-136, albeit with SNM1A showing a greater capacity to achieve this. This is consistent with the proposal that SNM1A and SNM1B might exhibit some redundancy in ICL repair. Together, our work establishes differences in the substrate selectivities of SNM1A and SNM1B that are likely to be relevant to their in vivo roles and which might be exploited in the development of selective inhibitors. PMID:22692201

B-DNA to Z-DNA structural transitions in the SV40 enhancer: stabilization of Z-DNA in negatively supercoiled DNA minicircles

NASA Technical Reports Server (NTRS)

Gruskin, E. A.; Rich, A.

1993-01-01

During replication and transcription, the SV40 control region is subjected to significant levels of DNA unwinding. There are three, alternating purine-pyrimidine tracts within this region that can adopt the Z-DNA conformation in response to negative superhelix density: a single copy of ACACACAT and two copies of ATGCATGC. Since the control region is essential for both efficient transcription and replication, B-DNA to Z-DNA transitions in these vital sequence tracts may have significant biological consequences. We have synthesized DNA minicircles to detect B-DNA to Z-DNA transitions in the SV40 enhancer, and to determine the negative superhelix density required to stabilize the Z-DNA. A variety of DNA sequences, including the entire SV40 enhancer and the two segments of the enhancer with alternating purine-pyrimidine tracts, were incorporated into topologically relaxed minicircles. Negative supercoils were generated, and the resulting topoisomers were resolved by electrophoresis. Using an anti-Z-DNA Fab and an electrophoretic mobility shift assay, Z-DNA was detected in the enhancer-containing minicircles at a superhelix density of -0.05. Fab saturation binding experiments demonstrated that three, independent Z-DNA tracts were stabilized in the supercoiled minicircles. Two other minicircles, each with one of the two alternating purine-pyrimidine tracts, also contained single Z-DNA sites. These results confirm the identities of the Z-DNA-forming sequences within the control region. Moreover, the B-DNA to Z-DNA transitions were detected at superhelix densities observed during normal replication and transcription processes in the SV40 life cycle.

Exposure of Metarhizium acridum mycelium to light induces tolerance to UV-B radiation.

PubMed

Brancini, Guilherme T P; Rangel, Drauzio E N; Braga, Gilberto Ú L

2016-03-01

Metarhizium acridum is an entomopathogenic fungus commonly used as a bioinsecticide. The conidium is the fungal stage normally employed as field inoculum in biological control programs and must survive under field conditions such as high ultraviolet-B (UV-B) exposure. Light, which is an important stimulus for many fungi, has been shown to induce the production of M. robertsii conidia with increased stress tolerance. Here we show that a two-hour exposure to white or blue/UV-A light of fast-growing mycelium induces tolerance to subsequent UV-B irradiation. Red light, however, does not have the same effect. In addition, we established that this induction can take place with as little as 1 min of white-light exposure. This brief illumination scheme could be relevant in future studies of M. acridum photobiology and for the production of UV-B resistant mycelium used in mycelium-based formulations for biological control. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Polymyxin B causes DNA damage in HK-2 cells and mice.

PubMed

Yun, B; Zhang, T; Azad, M A K; Wang, J; Nowell, C J; Kalitsis, P; Velkov, T; Hudson, D F; Li, J

2018-03-20

Increasing incidence of multidrug-resistant bacteria presents an imminent risk to global health. Polymyxins are 'last-resort' antibiotics against Gram-negative 'superbugs'; however, nephrotoxicity remains a key impediment in their clinical use. Molecular mechanisms underlying this nephrotoxicity remain poorly defined. Here, we examined the pathways which led to polymyxin B induced cell death in vitro and in vivo. Human proximal tubular cells were treated with polymyxin B (12.5-100 μM) for up to 24 h and showed a significant increase in micronuclei frequency, as well as abnormal mitotic events (over 40% in treated cells, p < 0.05). Time-course studies were performed using a mouse nephrotoxicity model (cumulative 72 mg/kg). Kidneys were collected over 48 h and investigated for histopathology and DNA damage. Notable increases in γH2AX foci (indicative of double-stranded breaks) were observed in both cell culture (up to ~ 44% cells with 5+ foci at 24 h, p < 0.05) and mice treated with polymyxin B (up to ~ 25%, p < 0.05). Consistent with these results, in vitro assays showed high binding affinity of polymyxin B to DNA. Together, our results indicate that polymyxin B nephrotoxicity is associated with DNA damage, leading to chromosome missegregation and genome instability. This novel mechanistic information may lead to new strategies to overcome the nephrotoxicity of this important last-line class of antibiotics.

Lanthanum (III) regulates the nitrogen assimilation in soybean seedlings under ultraviolet-B radiation.

PubMed

Huang, Guangrong; Wang, Lihong; Zhou, Qing

2013-01-01

Ultraviolet-B (UV-B, 280-320 nm) radiation has seriously affected the growth of plants. Finding the technology/method to alleviate the damage of UV-B radiation has become a frontal topic in the field of environmental science. The pretreatment with rare earth elements (REEs) is an effective method, but the regulation mechanism of REEs is unknown. Here, the regulation effects of lanthanum (La(III)) on nitrogen assimilation in soybean seedlings (Glycine max L.) under ultraviolet-B radiation were investigated to elucidate the regulation mechanism of REEs on plants under UV-B radiation. UV-B radiation led to the inhibition in the activities of the key enzymes (nitrate reductase, glutamine synthetase, glutamate synthase) in the nitrogen assimilation, the decrease in the contents of nitrate and soluble proteins, as well as the increase in the content of amino acid in soybean seedlings. The change degree of UV-B radiation at the high level (0.45 W m(-2)) was higher than that of UV-B radiation at the low level (0.15 W m(-2)). The pretreatment with 20 mg L(-1) La(III) could alleviate the effects of UV-B radiation on the activities of nitrate reductase, glutamine synthetase, glutamate synthase, and glutamate dehydrogenase, promoting amino acid conversion and protein synthesis in soybean seedlings. The regulation effect of La(III) under UV-B radiation at the low level was better than that of UV-B radiation at the high level. The results indicated that the pretreatment with 20 mg L(-1) La(III) could alleviate the inhibition of UV-B radiation on nitrogen assimilation in soybean seedlings.

Role of Ultraviolet Radiation in Papillomavirus-Induced Disease

PubMed Central

Uberoi, Aayushi; Yoshida, Satoshi; Frazer, Ian H.; Pitot, Henry C.; Lambert, Paul F.

2016-01-01

Human papillomaviruses are causally associated with 5% of human cancers. The recent discovery of a papillomavirus (MmuPV1) that infects laboratory mice provides unique opportunities to study the life cycle and pathogenesis of papillomaviruses in the context of a genetically manipulatable host organism. To date, MmuPV1-induced disease has been found largely to be restricted to severely immunodeficient strains of mice. In this study, we report that ultraviolet radiation (UVR), specifically UVB spectra, causes wild-type strains of mice to become highly susceptible to MmuPV1-induced disease. MmuPV1-infected mice treated with UVB develop warts that progress to squamous cell carcinoma. Our studies further indicate that UVB induces systemic immunosuppression in mice that correlates with susceptibility to MmuPV1-associated disease. These findings provide new insight into how MmuPV1 can be used to study the life cycle of papillomaviruses and their role in carcinogenesis, the role of host immunity in controlling papillomavirus-associated pathogenesis, and a basis for understanding in part the role of UVR in promoting HPV infection in humans. PMID:27244228

Role of Ultraviolet Radiation in Papillomavirus-Induced Disease.

PubMed

Uberoi, Aayushi; Yoshida, Satoshi; Frazer, Ian H; Pitot, Henry C; Lambert, Paul F

2016-05-01

Human papillomaviruses are causally associated with 5% of human cancers. The recent discovery of a papillomavirus (MmuPV1) that infects laboratory mice provides unique opportunities to study the life cycle and pathogenesis of papillomaviruses in the context of a genetically manipulatable host organism. To date, MmuPV1-induced disease has been found largely to be restricted to severely immunodeficient strains of mice. In this study, we report that ultraviolet radiation (UVR), specifically UVB spectra, causes wild-type strains of mice to become highly susceptible to MmuPV1-induced disease. MmuPV1-infected mice treated with UVB develop warts that progress to squamous cell carcinoma. Our studies further indicate that UVB induces systemic immunosuppression in mice that correlates with susceptibility to MmuPV1-associated disease. These findings provide new insight into how MmuPV1 can be used to study the life cycle of papillomaviruses and their role in carcinogenesis, the role of host immunity in controlling papillomavirus-associated pathogenesis, and a basis for understanding in part the role of UVR in promoting HPV infection in humans.

Defect of Fe-S cluster binding by DNA polymerase δ in yeast suppresses UV-induced mutagenesis, but enhances DNA polymerase ζ - dependent spontaneous mutagenesis.

PubMed

Stepchenkova, E I; Tarakhovskaya, E R; Siebler, H M; Pavlov, Y I

2017-01-01

Eukaryotic genomes are duplicated by a complex machinery, utilizing high fidelity replicative B-family DNA polymerases (pols) α, δ and ε. Specialized error-prone pol ζ, the fourth B-family member, is recruited when DNA synthesis by the accurate trio is impeded by replication stress or DNA damage. The damage tolerance mechanism dependent on pol ζ prevents DNA/genome instability and cell death at the expense of increased mutation rates. The pol switches occurring during this specialized replication are not fully understood. The loss of pol ζ results in the absence of induced mutagenesis and suppression of spontaneous mutagenesis. Disruption of the Fe-S cluster motif that abolish the interaction of the C-terminal domain (CTD) of the catalytic subunit of pol ζ with its accessory subunits, which are shared with pol δ, leads to a similar defect in induced mutagenesis. Intriguingly, the pol3-13 mutation that affects the Fe-S cluster in the CTD of the catalytic subunit of pol δ also leads to defective induced mutagenesis, suggesting the possibility that Fe-S clusters are essential for the pol switches during replication of damaged DNA. We confirmed that yeast strains with the pol3-13 mutation are UV-sensitive and defective in UV-induced mutagenesis. However, they have increased spontaneous mutation rates. We found that this increase is dependent on functional pol ζ. In the pol3-13 mutant strain with defective pol δ, there is a sharp increase in transversions and complex mutations, which require functional pol ζ, and an increase in the occurrence of large deletions, whose size is controlled by pol ζ. Therefore, the pol3-13 mutation abrogates pol ζ-dependent induced mutagenesis, but allows for pol ζ recruitment for the generation of spontaneous mutations and prevention of larger deletions. These results reveal differential control of the two major types of pol ζ-dependent mutagenesis by the Fe-S cluster present in replicative pol δ. Copyright © 2016

Protective effects of antioxidin-RL from Odorrana livida against ultraviolet B-irradiated skin photoaging.

PubMed

Qin, Di; Lee, Wen-Hui; Gao, Zhiqin; Zhang, Weifen; Peng, Meiyu; Sun, Tongyi; Gao, Yuanyuan

2018-03-01

The unavoidable daily exposure of the skin to ultraviolet (UV) B radiation is proven to have deleterious effects. The action mechanism of antioxidin-RL, an antioxidant peptide purified from skin secretions of frog Odorrana livida with amino acid sequence of AMRLTYNRPCIYAT, is well characterized by NMR titration and mutation based on ABTS + scavenging activities. In order to explore the protective effects of antioxidin-RL against UVB-irradiated skin photoaging, cell uptake assay was used to detect the location of antioxidin-RL molecules serving various biological functions in the cells. The protective effects of antioxidin-RL on UVB-induced response were examined in vitro and in vivo. Results showed that antioxidin-RL successfully penetrated the cell membrane and exerted a positive effect on cell migration. It also effectively inhibited the UVB-induced excessive production of ROS and prevented oxidative damage to DNAs and proteins. Moreover, the mRNA expressions of MMP-1, VEGF, COX-2, and pro-inflammatory cytokines, such as IL-6 and TNF-α in antioxidin-RL-treated HaCaT and HSF cells were significantly down-regulated whereas those of FGF, procollagen type I and TGF-β1 up-regulated. Antioxidin-RL effectively prevented UVB-induced erythema on mouse skin, thereby inhibiting UVB-induced skin thickening and inflammation and increasing collagen deposition as demonstrated by in vivo experiments. Hence, the novel antioxidant peptide antioxidin-RL can effectively reduce UVB-induced skin reactions in vivo and in vitro, providing potential molecules against UVB-induced inflammation and photoaging. Copyright © 2018 Elsevier Inc. All rights reserved.

Potential of the homeopathic remedy, Arnica Montana 30C, to reduce DNA damage in Escherichia coli exposed to ultraviolet irradiation through up-regulation of nucleotide excision repair genes.

PubMed

Das, Sreemanti; Saha, Santu Kumar; De, Arnab; Das, Durba; Khuda-Bukhsh, Anisur Rahman

2012-03-01

To examine to what degree an ultra-highly diluted homeopathic remedy, Arnica Montana 30C (AM-30C), used in the treatment of shock and injury, can modulate the expression of nucleotide excision repair genes in Escherichia coli exposed to ultraviolet (UV) irradiation. E. coli were cultured to their log phase in a standard Luria-Bertani medium and then exposed to sublethal doses of UV irradiation at 25 and 50 J/m(2) for 22.5 and 45 s, respectively. The UV-exposed bacteria were then supplemented with either AM-30C (drug) or placebo (P-30C). The drug-treated and placebo-treated bacteria were subjected to assay for DNA damage and oxidative stress 90 min after UV exposure. Several protocols like comet assay, gel electrophoresis for DNA ladder and intracellular reactive oxygen species (ROS) generation, and biomarker measurement like superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) were conducted. The mRNA expressions of the excision repair genes like ultraviolet repair uvrA, B and C genes (or also known as excision repair genes) were estimated by reverse transcription-polymerase chain reaction method. The UV-exposed bacteria showed DNA damage and oxidative stress, as revealed by an increase in ROS generation, and a decrease in SOD, CAT and GSH activities. As compared to placebo, the AM-30C-treated bacteria showed less DNA damage and oxidative stress as manifested by a decrease in ROS generation, and an increase in SOD, CAT and GSH activities. AM-30C also up-regulated the expression of repair genes as compared to the control. AM-30C helped repair the DNA damage through up-regulation of repair genes and also ameliorated the oxidative stress through the reduction of ROS generation and suitable modulation of anti-oxidative stress enzymes.

Inhibition of nuclear factor kappaB proteins-platinated DNA interactions correlates with cytotoxic effectiveness of the platinum complexes

PubMed Central

Brabec, Viktor; Kasparkova, Jana; Kostrhunova, Hana; Farrell, Nicholas P.

2016-01-01

Nuclear DNA is the target responsible for anticancer activity of platinum anticancer drugs. Their activity is mediated by altered signals related to programmed cell death and the activation of various signaling pathways. An example is activation of nuclear factor kappaB (NF-κB). Binding of NF-κB proteins to their consensus sequences in DNA (κB sites) is the key biochemical activity responsible for the biological functions of NF-κB. Using gel-mobility-shift assays and surface plasmon resonance spectroscopy we examined the interactions of NF-κB proteins with oligodeoxyribonucleotide duplexes containing κB site damaged by DNA adducts of three platinum complexes. These complexes markedly differed in their toxic effects in tumor cells and comprised highly cytotoxic trinuclear platinum(II) complex BBR3464, less cytotoxic conventional cisplatin and ineffective transplatin. The results indicate that structurally different DNA adducts of these platinum complexes exhibit a different efficiency to affect the affinity of the platinated DNA (κB sites) to NF-κB proteins. Our results support the hypothesis that structural perturbations induced in DNA by platinum(II) complexes correlate with their higher efficiency to inhibit binding of NF-κB proteins to their κB sites and cytotoxicity as well. However, the full generalization of this hypothesis will require to evaluate a larger series of platinum(II) complexes. PMID:27574114

Inhibition of nuclear factor kappaB proteins-platinated DNA interactions correlates with cytotoxic effectiveness of the platinum complexes.

PubMed

Brabec, Viktor; Kasparkova, Jana; Kostrhunova, Hana; Farrell, Nicholas P

2016-08-30

Nuclear DNA is the target responsible for anticancer activity of platinum anticancer drugs. Their activity is mediated by altered signals related to programmed cell death and the activation of various signaling pathways. An example is activation of nuclear factor kappaB (NF-κB). Binding of NF-κB proteins to their consensus sequences in DNA (κB sites) is the key biochemical activity responsible for the biological functions of NF-κB. Using gel-mobility-shift assays and surface plasmon resonance spectroscopy we examined the interactions of NF-κB proteins with oligodeoxyribonucleotide duplexes containing κB site damaged by DNA adducts of three platinum complexes. These complexes markedly differed in their toxic effects in tumor cells and comprised highly cytotoxic trinuclear platinum(II) complex BBR3464, less cytotoxic conventional cisplatin and ineffective transplatin. The results indicate that structurally different DNA adducts of these platinum complexes exhibit a different efficiency to affect the affinity of the platinated DNA (κB sites) to NF-κB proteins. Our results support the hypothesis that structural perturbations induced in DNA by platinum(II) complexes correlate with their higher efficiency to inhibit binding of NF-κB proteins to their κB sites and cytotoxicity as well. However, the full generalization of this hypothesis will require to evaluate a larger series of platinum(II) complexes.

Gene 33/Mig6 inhibits hexavalent chromium-induced DNA damage and cell transformation in human lung epithelial cells

PubMed Central

Park, Soyoung; Li, Cen; Zhao, Hong; Darzynkiewicz, Zbigniew; Xu, Dazhong

2016-01-01

Hexavalent Chromium [Cr(VI)] compounds are human lung carcinogens and environmental/occupational hazards. The molecular mechanisms of Cr(VI) carcinogenesis appear to be complex and are poorly defined. In this study, we investigated the potential role of Gene 33 (ERRFI1, Mig6), a multifunctional adaptor protein, in Cr(VI)-mediated lung carcinogenesis. We show that the level of Gene 33 protein is suppressed by both acute and chronic Cr(VI) treatments in a dose- and time-dependent fashion in BEAS-2B lung epithelial cells. The inhibition also occurs in A549 lung bronchial carcinoma cells. Cr(VI) suppresses Gene 33 expression mainly through post-transcriptional mechanisms, although the mRNA level of gene 33 also tends to be lower upon Cr(VI) treatments. Cr(VI)-induced DNA damage appears primarily in the S phases of the cell cycle despite the high basal DNA damage signals at the G2M phase. Knockdown of Gene 33 with siRNA significantly elevates Cr(VI)-induced DNA damage in both BEAS-2B and A549 cells. Depletion of Gene 33 also promotes Cr(VI)-induced micronucleus (MN) formation and cell transformation in BEAS-2B cells. Our results reveal a novel function of Gene 33 in Cr(VI)-induced DNA damage and lung epithelial cell transformation. We propose that in addition to its role in the canonical EGFR signaling pathway and other signaling pathways, Gene 33 may also inhibit Cr(VI)-induced lung carcinogenesis by reducing DNA damage triggered by Cr(VI). PMID:26760771

The flavonoid, fisetin, inhibits UV radiation-induced oxidative stress and the activation of NF-kappaB and MAPK signaling in human lens epithelial cells.

PubMed

Yao, Ke; Zhang, Li; Zhang, Yidong; Ye, PanPan; Zhu, Ning

2008-01-01

Ultraviolet (UV) radiation-induced oxidative stress plays a significant role in the progression of cataracts. This study investigated the photoprotective effect of fisetin on UV radiation-induced oxidative stress in human lens epithelial cells and the possible molecular mechanism involved. SRA01/04 cells exposed to different doses of ultraviolet B (UVB) were cultured with various concentrations of fisetin and subsequently monitored for cell viability by the 4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT) assay. The effect of fisetin on the generation of reactive oxygen species (ROS) of SRA01/04 cells was determined by flow cytometry. Translocation of nuclear factor kappa-B (NF-kappaB) was examined by immunocytochemistry. Expression of NF-kappaB/P65, inhibiter kappa B (IkappaB), and mitogen activated protein kinase (MAPK) proteins were measured by western blot. Treatment of SRA01/04 cells with fisetin inhibited UVB-induced cell death and the generation of ROS. Fisetin inhibited UVB-induced activation and translocation of NF-kappaB/p65, which was mediated through an inhibition of the degradation and activation of IkappaB. Fisetin also inhibited UVB-induced phosphorylation of the p38 and c-Jun N-terminal kinase (JNK) proteins of the MAPK family at various time points studied. The flavonoid, fisetin, could be useful in attenuation of UV radiation-induced oxidative stress and the activation of NF-kappaB and MAPK signaling in human lens epithelial cells, which suggests that fisetin has a potential protective effect against cataractogenesis.

NF-κB mediates Gadd45β expression and DNA demethylation in the hippocampus during fear memory formation.

PubMed

Jarome, Timothy J; Butler, Anderson A; Nichols, Jessica N; Pacheco, Natasha L; Lubin, Farah D

2015-01-01

Gadd45-mediated DNA demethylation mechanisms have been implicated in the process of memory formation. However, the transcriptional mechanisms involved in the regulation of Gadd45 gene expression during memory formation remain unexplored. NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) controls transcription of genes in neurons and is a critical regulator of synaptic plasticity and memory formation. In silico analysis revealed several NF-κB (p65/RelA and cRel) consensus sequences within the Gadd45β gene promoter. Whether NF-κB activity regulates Gadd45 expression and associated DNA demethylation in neurons during memory formation is unknown. Here, we found that learning in a fear conditioning paradigm increased Gadd45β gene expression and brain-derivedneurotrophic factor (BDNF) DNA demethylation in area CA1 of the hippocampus, both of which were prevented with pharmacological inhibition of NF-κB activity. Further experiments found that conditional mutations in p65/RelA impaired fear memory formation but did not alter changes in Gadd45β expression. The learning-induced increases in Gadd45β mRNA levels, Gadd45β binding at the BDNF gene and BDNF DNA demethylation were blocked in area CA1 of the c-rel knockout mice. Additionally, local siRNA-mediated knockdown of c-rel in area CA1 prevented fear conditioning-induced increases in Gadd45β expression and BDNF DNA demethylation, suggesting that c-Rel containing NF-κB transcription factor complex is responsible for Gadd45β regulation during memory formation. Together, these results support a novel transcriptional role for NF-κB in regulation of Gadd45β expression and DNA demethylation in hippocampal neurons during fear memory.

Carnosine ameliorates lens protein turbidity formations by inhibiting calpain proteolysis and ultraviolet C-induced degradation.

PubMed

Liao, Jiahn-Haur; Lin, I-Lin; Huang, Kai-Fa; Kuo, Pei-Ting; Wu, Shih-Hsiung; Wu, Tzu-Hua

2014-06-25

Carnosine (CAR) is an endogenous peptide and present in lens, but there is little evidence for its effectiveness in calpain-induced proteolysis inhibition and its differential effects toward different wavelengths of ultraviolet (UV) irradiation. This study aimed to develop three in vitro cataract models to compare the mechanisms underlying the protective activities of CAR. Crude crystallins extracted from porcine lenses were used for antiproteolysis assays, and purified γ-crystallins were used for anti-UV assays. The turbidity in those in vitro models mimics cataract formation and was assayed by measuring optical density (OD) at 405 nm. The effectiveness of CAR on calpain-induced proteolysis was studied at 37 and 58 °C. Patterns of proteins were then analyzed by SDS-PAGE. The turbidity was reduced significantly (p<0.05) at 60 min measurements with the increased concentration of CAR (10-300 mM). SDS-PAGE showed that the decreased intensities at both ∼28 and ∼30 kDa protein bands in heat-enhanced assays were ameliorated by CAR at ≥10 mM concentrations. In UV-B studies, CAR (200, 300 mM) reduced the turbidity of γ-crystallin significantly (p<0.05) at 6 h observations. The turbidity of samples containing γ-crystallins was ameliorated while incubated with CAR (100, 300 mM) significantly (p<0.05) following 4 h of exposure to UV-C. SDS-PAGE showed that the presence of CAR reduced UV-B-induced aggregation of γ-crystallins at ∼44 kDa and resulted in less loss of γ-crystallin following UV-C exposure. The result of modeling also suggests that CAR acts as an inhibitor of calpain. In conclusion, CAR protects lens proteins more readily by inhibiting proteolysis and UV-C-induced degradation than aggregation induced by UV-B irradiation.

Impact of enhanced ultraviolet-B irradiance on cotton growth, development, yield, and qualities under field conditions

Treesearch

Wei Gao; Youfei Zheng; James R. Slusser; Gordon M. Heisler

2003-01-01

The stratospheric ozone depletion and enhanced solar ultraviolet-B (UV-B) irradiance may have adverse impacts on the productivity of agricultural crops. The effect of UV-B enhancements on agricultural crops includes reduction in yield, alteration in species competition, decrease in photosynthetic activity, susceptibility to disease, and changes in structure and...

Systematic identification of DNA variants associated with ultraviolet radiation using a novel Geographic-Wide Association Study (GeoWAS).

PubMed

Hsu, Irving; Chen, Rong; Ramesh, Aditya; Corona, Erik; Kang, Hyunseok Peter; Ruau, David; Butte, Atul J

2013-06-20

Long-term environmental variables are widely understood to play important roles in DNA variation. Previously, clinical studies examining the impacts of these variables on the human genome were localized to a single country, and used preselected DNA variants. Furthermore, clinical studies or surveys are either not available or difficult to carry out for developing countries. A systematic approach utilizing bioinformatics to identify associations among environmental variables, genetic variation, and diseases across various geographical locations is needed but has been lacking. Using a novel Geographic-Wide Association Study (GeoWAS) methodology, we identified Single Nucleotide Polymorphisms (SNPs) in the Human Genome Diversity Project (HGDP) with population allele frequencies associated geographical ultraviolet radiation exposure, and then assessed the diseases known to be assigned with these SNPs. 2,857 radiation SNPs were identified from over 650,000 SNPs in 52 indigenous populations across the world. Using a quantitative disease-SNP database curated from 5,065 human genetic papers, we identified disease associations with those radiation SNPs. The correlation of the rs16891982 SNP in the SLC45A2 gene with melanoma was used as a case study for analysis of disease risk, and the results were consistent with the incidence and mortality rates of melanoma in published scientific literature. Finally, by analyzing the ontology of genes in which the radiation SNPs were significantly enriched, potential associations between SNPs and neurological disorders such as Alzheimer's disease were hypothesized. A systematic approach using GeoWAS has enabled us to identify DNA variation associated with ultraviolet radiation and their connections to diseases such as skin cancers. Our analyses have led to a better understating at the genetic level of why certain diseases are more predominant in specific geographical locations, due to the interactions between environmental variables such

Biochemical Characterization of a Mycobacteriophage Derived DnaB Ortholog Reveals New Insight into the Evolutionary Origin of DnaB Helicases

PubMed Central

Bhowmik, Priyanka; Das Gupta, Sujoy K.

2015-01-01

The bacterial replicative helicases known as DnaB are considered to be members of the RecA superfamily. All members of this superfamily, including DnaB, have a conserved C- terminal domain, known as the RecA core. We unearthed a series of mycobacteriophage encoded proteins in which the RecA core domain alone was present. These proteins were phylogenetically related to each other and formed a distinct clade within the RecA superfamily. A mycobacteriophage encoded protein, Wildcat Gp80 that roots deep in the DnaB family, was found to possess a core domain having significant sequence homology (Expect value < 10-5) with members of this novel cluster. This indicated that Wildcat Gp80, and by extrapolation, other members of the DnaB helicase family, may have evolved from a single domain RecA core polypeptide belonging to this novel group. Biochemical investigations confirmed that Wildcat Gp80 was a helicase. Surprisingly, our investigations also revealed that a thioredoxin tagged truncated version of the protein in which the N-terminal sequences were removed was fully capable of supporting helicase activity, although its ATP dependence properties were different. DnaB helicase activity is thus, primarily a function of the RecA core although additional N-terminal sequences may be necessary for fine tuning its activity and stability. Based on sequence comparison and biochemical studies we propose that DnaB helicases may have evolved from single domain RecA core proteins having helicase activities of their own, through the incorporation of additional N-terminal sequences. PMID:26237048

Inhibition of the Induced Formation of Tryptophanase in Escherichia coli by Near-Ultraviolet Radiation

PubMed Central

Swenson, P. A.; Setlow, R. B.

1970-01-01

Induced formation of tryptophanase in Escherichia coli B/r is temporarily inhibited by near-ultraviolet (UV) irradiation. The inhibition is greater when irradiation is at 5 C than when at room temperature. Hence, the inhibition is the result of a photochemical, rather than photoenzymatic, alteration of some cellular component. The action spectrum has a peak in the region of 334 nm and is similar to that for growth delay. However, inhibition of tryptophanase formation is more sensitive to near-UV irradiation than are growth, respiration, and the induced formation of β-galactosidase. Thus, for tryptophanase the lack of formation cannot be due to general inhibition of metabolism. Pyridoxal phosphate absorbs in the near-UV region of the spectrum and is a cofactor for tryptophanase, but this enzyme in induced cells is not inactivated by near UV-radiations. An experiment in which toluene-treated suspensions from irradiated and unirradiated cells were mixed showed that irradiation does not cause the formation of an inhibitor of tryptophanase activity. The possibility remains that the absorption of radiant energy by pyridoxal phosphate interferes with the synthesis of tryptophanase. PMID:4914082

Home versus outpatient ultraviolet B phototherapy for mild to severe psoriasis: pragmatic multicentre randomised controlled non-inferiority trial (PLUTO study)

PubMed Central

Buskens, Erik; van Weelden, Huib; Steegmans, Paul H A; Bruijnzeel-Koomen, Carla A F M; Sigurdsson, Vigfús

2009-01-01

Objective To determine whether ultraviolet B phototherapy at home is equally safe and equally effective as ultraviolet B phototherapy in an outpatient setting for patients with psoriasis. Design Pragmatic multicentre single blind randomised clinical trial (PLUTO study). Setting Dermatology departments of 14 hospitals in the Netherlands. Participants 196 patients with psoriasis who were clinically eligible for narrowband (TL-01) ultraviolet B phototherapy. The first 105 consecutive patients were also followed for one year after therapy. Intervention Ultraviolet B phototherapy at home using a TL-01 home phototherapy unit compared with standard narrowband ultraviolet B phototherapy in an outpatient setting. Both therapies were done in a setting reflecting routine daily practice in the Netherlands. Main outcome measures The main outcome measure was effectiveness as measured by the proportion of patients with a 50% or more reduction of the baseline psoriasis area and severity index (PASI) or self administered psoriasis area and severity index (SAPASI), called the PASI 50 and SAPASI 50 (relevant treatment effect). Another outcome of effectiveness was the percentage reduction in median scores on the PASI as well as SAPASI. Also the proportions of patients reaching the PASI 75 and SAPASI 75 (successful treatment effect), and the PASI 90 and SAPASI 90 (almost complete clearance) were calculated. Other secondary outcomes were quality of life (SF-36, psoriasis disability index), burden of treatment (questionnaire), patients’ preferences and satisfaction (questionnaire), and dosimetry and short term side effects (diary). Results 82% of the patients treated at home compared with 79% of the patients treated in an outpatient setting reached the SAPASI 50 (difference 2.8%, 95% confidence interval −8.6% to 14.2%), and 70% compared with 73% reached the PASI 50 (−2.3%, −15.7% to 11.1%). For patients treated at home the median SAPASI score decreased 82% (from 6.7 to 1.2) and

Macrophage activation induced by Brucella DNA suppresses bacterial intracellular replication via enhancing NO production.

PubMed

Liu, Ning; Wang, Lin; Sun, Changjiang; Yang, Li; Tang, Bin; Sun, Wanchun; Peng, Qisheng

2015-12-01

Brucella DNA can be sensed by TLR9 on endosomal membrane and by cytosolic AIM2-inflammasome to induce proinflammatory cytokine production that contributes to partially activate innate immunity. Additionally, Brucella DNA has been identified to be able to act as a major bacterial component to induce type I IFN. However, the role of Brucella DNA in Brucella intracellular growth remains unknown. Here, we showed that stimulation with Brucella DNA promote macrophage activation in TLR9-dependent manner. Activated macrophages can suppresses wild type Brucella intracellular replication at early stage of infection via enhancing NO production. We also reported that activated macrophage promotes bactericidal function of macrophages infected with VirB-deficient Brucella at the early or late stage of infection. This study uncovers a novel function of Brucella DNA, which can help us further elucidate the mechanism of Brucella intracellular survival. Copyright © 2015 Elsevier Ltd. All rights reserved.

Focal brain lesions induced with ultraviolet irradiation.

PubMed

Nakata, Mariko; Nagasaka, Kazuaki; Shimoda, Masayuki; Takashima, Ichiro; Yamamoto, Shinya

2018-05-22

Lesion and inactivation methods have played important roles in neuroscience studies. However, traditional techniques for creating a brain lesion are highly invasive, and control of lesion size and shape using these techniques is not easy. Here, we developed a novel method for creating a lesion on the cortical surface via 365 nm ultraviolet (UV) irradiation without breaking the dura mater. We demonstrated that 2.0 mWh UV irradiation, but not the same amount of non-UV light irradiation, induced an inverted bell-shaped lesion with neuronal loss and accumulation of glial cells. Moreover, the volume of the UV irradiation-induced lesion depended on the UV light exposure amount. We further succeeded in visualizing the lesioned site in a living animal using magnetic resonance imaging (MRI). Importantly, we also observed using an optical imaging technique that the spread of neural activation evoked by adjacent cortical stimulation disappeared only at the UV-irradiated site. In summary, UV irradiation can induce a focal brain lesion with a stable shape and size in a less invasive manner than traditional lesioning methods. This method is applicable to not only neuroscientific lesion experiments but also studies of the focal brain injury recovery process.

Mechanisms of free radical-induced damage to DNA.

PubMed

Dizdaroglu, Miral; Jaruga, Pawel

2012-04-01

Endogenous and exogenous sources cause free radical-induced DNA damage in living organisms by a variety of mechanisms. The highly reactive hydroxyl radical reacts with the heterocyclic DNA bases and the sugar moiety near or at diffusion-controlled rates. Hydrated electron and H atom also add to the heterocyclic bases. These reactions lead to adduct radicals, further reactions of which yield numerous products. These include DNA base and sugar products, single- and double-strand breaks, 8,5'-cyclopurine-2'-deoxynucleosides, tandem lesions, clustered sites and DNA-protein cross-links. Reaction conditions and the presence or absence of oxygen profoundly affect the types and yields of the products. There is mounting evidence for an important role of free radical-induced DNA damage in the etiology of numerous diseases including cancer. Further understanding of mechanisms of free radical-induced DNA damage, and cellular repair and biological consequences of DNA damage products will be of outmost importance for disease prevention and treatment.

Faster DNA Repair of Ultraviolet-Induced Cyclobutane Pyrimidine Dimers and Lower Sensitivity to Apoptosis in Human Corneal Epithelial Cells than in Epidermal Keratinocytes

PubMed Central

Mallet, Justin D.; Bastien, Nathalie; Gendron, Sébastien P.; Rochette, Patrick J.

2016-01-01

Absorption of UV rays by DNA generates the formation of mutagenic cyclobutane pyrimidine dimers (CPD) and pyrimidine (6–4) pyrimidone photoproducts (6-4PP). These damages are the major cause of skin cancer because in turn, they can lead to signature UV mutations. The eye is exposed to UV light, but the cornea is orders of magnitude less prone to UV-induced cancer. In an attempt to shed light on this paradox, we compared cells of the corneal epithelium and the epidermis for UVB-induced DNA damage frequency, repair and cell death sensitivity. We found similar CPD levels but a 4-time faster UVB-induced CPD, but not 6-4PP, repair and lower UV-induced apoptosis sensitivity in corneal epithelial cells than epidermal. We then investigated levels of DDB2, a UV-induced DNA damage recognition protein mostly impacting CPD repair, XPC, essential for the repair of both CPD and 6-4PP and p53 a protein upstream of the genotoxic stress response. We found more DDB2, XPC and p53 in corneal epithelial cells than in epidermal cells. According to our results analyzing the protein stability of DDB2 and XPC, the higher level of DDB2 and XPC in corneal epithelial cells is most likely due to an increased stability of the protein. Taken together, our results show that corneal epithelial cells have a better efficiency to repair UV-induced mutagenic CPD. On the other hand, they are less prone to UV-induced apoptosis, which could be related to the fact that since the repair is more efficient in the HCEC, the need to eliminate highly damaged cells by apoptosis is reduced. PMID:27611318

Cost effectiveness of home ultraviolet B phototherapy for psoriasis: economic evaluation of a randomised controlled trial (PLUTO study).

PubMed

Koek, Mayke B G; Sigurdsson, Vigfús; van Weelden, Huib; Steegmans, Paul H A; Bruijnzeel-Koomen, Carla A F M; Buskens, Erik

2010-04-20

To assess the costs and cost effectiveness of phototherapy with ultraviolet B light provided at home compared with outpatient ultraviolet B phototherapy for psoriasis. Cost utility, cost effectiveness, and cost minimisation analyses performed alongside a pragmatic randomised clinical trial (the PLUTO study) at the end of phototherapy (mean 17.6 weeks) and at one year after the end of phototherapy (mean 68.4 weeks). Secondary care, provided by a dermatologist in the Netherlands. 196 adults with psoriasis who were clinically eligible for narrowband (TL-01) ultraviolet B phototherapy were recruited from the dermatology departments of 14 hospitals and were followed until the end of phototherapy. From the end of phototherapy onwards, follow-up was continued for an unselected, consecutive group of 105 patients for one year after end of phototherapy. Ultraviolet B phototherapy provided at home (intervention) and conventional outpatient ultraviolet B phototherapy (control) in a setting reflecting routine practice in the Netherlands. Both treatments used narrowband ultraviolet B lamps (TL-01). Total costs to society, quality adjusted life years (QALYs) as calculated using utilities measured by the EQ-5D questionnaire, and the number of days with a relevant treatment effect (>/=50% improvement of the baseline self administered psoriasis area and severity index (SAPASI)). Home phototherapy is at least as effective and safe as outpatient phototherapy, therefore allowing cost minimisation analyses (simply comparing costs). The average total costs by the end of phototherapy were euro800 for home treatment and euro752 for outpatient treatment, showing an incremental cost per patient of euro48 (95% CI euro-77 to euro174). The average total costs by one year after the end of phototherapy were euro1272 and euro1148 respectively (difference euro124, 95% CI euro-155 to euro403). Cost utility analyses revealed that patients experienced equal health benefits-that is, a gain of 0

EFFECTS OF ULTRAVIOLET-B LIGHT AND POLYAROMATIC HYDROCARBON EXPOSURE ON SEA URCHIN DEVELOPMENT AND BACTERIAL BIOLUMINESCENCE

EPA Science Inventory

Polycyclic aromatic hydrocarbons (PAHs) are relatively common contaminants of the Gulf of Mexico and may be activated to more toxic metabolites by ultraviolet-B (UV-B) light. A marine bacterial bioassay system (Vibrio fischeri) which focused on the reduction of luciferase-mediate...

Viability of Cladosporium herbarum spores under 157 nm laser and vacuum ultraviolet irradiation, low temperature (10 K) and vacuum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarantopoulou, E., E-mail: esarant@eie.gr; Stefi, A.; Kollia, Z.