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1.
Int J Radiat Biol ; 95(11): 1588-1596, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31294655

RESUMO

Purpose: The aim of this study is to investigate the effects of low frequency and intensity sinusoidal magnetic field (SMF) and pulsed magnetic field (PMF) exposure on the chronological aging and cellular stability of Saccharomyces cerevisiae.Materials and methods: The S. cerevisiae wild type strain (WS8105-1C) was exposed to SMF (2.45 mT, 50 Hz, continuous) and PMF (1.5 mT, 25 Hz, 8 h/day). Chronological aging was evaluated during 40 days. Survival was assayed by clonogenic assay and drop test. Cellular stability was studied by spontaneous mutation count and the index of respiratory competence (IRC).Results: We found that exposure to PMF produces an acceleration of cellular chronological aging, not observed in the groups treated with SMF. A decrease in the spontaneous frequency of mitochondrial mutation during aging was observed in PMF-treated samples. However, no alterations in the IRC during aging were found for both, SMF and PMF, treatments.Conclusions: Exposure to PMF produces the acceleration of aging and an alteration in cellular stability.


Assuntos
Ciclo Celular/efeitos da radiação , Campos Magnéticos , Saccharomyces cerevisiae/efeitos da radiação , Genótipo , Mitocôndrias/efeitos da radiação , Mutação/efeitos da radiação
2.
Int J Mol Sci ; 20(12)2019 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-31234590

RESUMO

When leaves receive excess light energy, excess reductants accumulate in chloroplasts. It is suggested that some of the reductants are oxidized by the mitochondrial respiratory chain. Alternative oxidase (AOX), a non-energy conserving terminal oxidase, was upregulated in the photosynthetic mutant of Arabidopsis thaliana, pgr5, which accumulated reductants in chloroplast stroma. AOX is suggested to have an important role in dissipating reductants under high light (HL) conditions, but its physiological importance and underlying mechanisms are not yet known. Here, we compared wild-type (WT), pgr5, and a double mutant of AOX1a-knockout plant (aox1a) and pgr5 (aox1a/pgr5) grown under high- and low-light conditions, and conducted physiological analyses. The net assimilation rate (NAR) was lower in aox1a/pgr5 than that in the other genotypes at the early growth stage, while the leaf area ratio was higher in aox1a/pgr5. We assessed detailed mechanisms in relation to NAR. In aox1a/pgr5, photosystem II parameters decreased under HL, whereas respiratory O2 uptake rates increased. Some intermediates in the tricarboxylic acid (TCA) cycle and Calvin cycle decreased in aox1a/pgr5, whereas γ-aminobutyric acid (GABA) and N-rich amino acids increased in aox1a/pgr5. Under HL, AOX may have an important role in dissipating excess reductants to prevent the reduction of photosynthetic electron transport and imbalance in primary metabolite levels.


Assuntos
Arabidopsis/fisiologia , Arabidopsis/efeitos da radiação , Transporte de Elétrons , Luz , Mitocôndrias/metabolismo , Mitocôndrias/efeitos da radiação , Proteínas Mitocondriais/metabolismo , Oxirredução , Oxirredutases/metabolismo , Fotossíntese/efeitos da radiação , Proteínas de Plantas/metabolismo , Biomarcadores , Metabolismo Energético , Regulação da Expressão Gênica
3.
Redox Biol ; 26: 101220, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31176262

RESUMO

Glioblastoma (GBM) has a poor prognosis despite intensive treatment with surgery and chemoradiotherapy. Previous studies using dose-escalated radiotherapy have demonstrated improved survival; however, increased rates of radionecrosis have limited its use. Development of radiosensitizers could improve patient outcome. In the present study, we report the use of sodium sulfide (Na2S), a hydrogen sulfide (H2S) donor, to selectively kill GBM cells (T98G and U87) while sparing normal human cerebral microvascular endothelial cells (hCMEC/D3). Na2S also decreased mitochondrial respiration, increased oxidative stress and induced γH2AX foci and oxidative base damage in GBM cells. Since Na2S did not significantly alter T98G capacity to perform non-homologous end-joining or base excision repair, it is possible that GBM cell killing could be attributed to increased damage induction due to enhanced reactive oxygen species production. Interestingly, Na2S enhanced mitochondrial respiration, produced a more reducing environment and did not induce high levels of DNA damage in hCMEC/D3. Taken together, this data suggests involvement of mitochondrial respiration in Na2S toxicity in GBM cells. The fact that survival of LN-18 GBM cells lacking mitochondrial DNA (ρ0) was not altered by Na2S whereas the survival of LN-18 ρ+ cells was compromised supports this conclusion. When cells were treated with Na2S and photon or proton radiation, GBM cell killing was enhanced, which opens the possibility of H2S being a radiosensitizer. Therefore, this study provides the first evidence that H2S donors could be used in GBM therapy to potentiate radiation-induced killing.


Assuntos
Reparo do DNA/efeitos dos fármacos , Sulfeto de Hidrogênio/farmacologia , Mitocôndrias/efeitos dos fármacos , Neuroglia/efeitos dos fármacos , Radiossensibilizantes/farmacologia , Sulfetos/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Linhagem Celular , Linhagem Celular Tumoral , Dano ao DNA , Reparo do DNA/efeitos da radiação , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/efeitos da radiação , Humanos , Sulfeto de Hidrogênio/química , Mitocôndrias/metabolismo , Mitocôndrias/efeitos da radiação , Neuroglia/patologia , Neuroglia/efeitos da radiação , Especificidade de Órgãos , Fosforilação Oxidativa/efeitos dos fármacos , Fosforilação Oxidativa/efeitos da radiação , Estresse Oxidativo , Fótons , Terapia com Prótons , Radiossensibilizantes/química , Espécies Reativas de Oxigênio/metabolismo , Sulfetos/química
4.
Int J Radiat Biol ; 95(7): 1043-1049, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31157572

RESUMO

In the 60 years since the inaugural edition of the International Journal of Radiation Biology, much of our understanding of the biological effects of solar radiation has changed. Earlier in the century, sunlight played a 'hero's' role in reducing disabling rickets, while today debate still continues on the amount of sun required before exposure reveals the 'villainous' side of solar radiation. Although knowledge of the ultra violet (UV) component of sunlight as a carcinogen has become widespread, skin cancer rates are still rising yearly. Twentieth century attitudes have seen an about-face in the field of dermatological sun protection, with sunscreens changing from recipes designed to promote a 'healthy tan' to formulations proven to block both ultraviolet B (UVB) and more recently, ultraviolet A (UVA), to minimize premature sun-aging and skin cancer risk. In the early 1960s, DNA was first found to exist within mitochondria, while recently the connections between mitochondrial changes and UV radiation exposure have been expanded. Sixty years ago, understanding of the endocrine systems of mammals was enjoying its infancy. Early discoveries that light, particularly natural light, could have profound effects on functions such as sleep patterns and hormonal balance were made, while today more advanced knowledge has led to lighting improvements having pronounced effects on human wellbeing. Photosensitization 60 years ago was a health concern for both humans and their domestic animals, while today chemically engineered photosensitizing drugs can be administered along with highly directed light to pinpoint delivery targets for drug action. Life on earth is inextricably bound up with solar radiation. This article attempts to outline many of the ways in which our opinions about solar radiation have changed since the journal's inception.


Assuntos
Radiobiologia/história , Luz Solar , Raios Ultravioleta , Animais , DNA/efeitos da radiação , Dano ao DNA , DNA Mitocondrial/metabolismo , História do Século XX , História do Século XXI , Humanos , Saúde Mental , Mitocôndrias/efeitos da radiação , Neoplasias/etiologia , Neoplasias/radioterapia , Fármacos Fotossensibilizantes , Raquitismo/radioterapia , Pele/efeitos da radiação , Envelhecimento da Pele/efeitos da radiação , Neoplasias Cutâneas/etiologia , Neoplasias Cutâneas/radioterapia , Vitamina D/metabolismo
5.
Int J Mol Sci ; 20(9)2019 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-31083373

RESUMO

Liquid crystal displays (LCDs) are used as screens in consumer electronics and are indispensable in the modern era of computing. LCDs utilize light-emitting diodes (LEDs) as backlight modules and emit high levels of blue light, which may cause retinal photoreceptor cell damage. However, traditional blue light filters may decrease the luminance of light and reduce visual quality. We adjusted the emitted light spectrum of LED backlight modules in LCDs and reduced the energy emission but maintained the luminance. The 661W photoreceptor cell line was used as the model system. We established a formula of the ocular energy exposure index (OEEI), which could be used as the indicator of LCD energy emission. Cell viability decreased and apoptosis increased significantly after exposure to LCDs with higher emitted energy. Cell damage occurred through the induction of oxidative stress and mitochondrial dysfunction. The molecular mechanisms included activation of the NF-κB pathway and upregulation of the expression of proteins associated with inflammation and apoptosis. The effect was correlated with OEEI intensity. We demonstrated that LCD exposure-induced photoreceptor damage was correlated with LCD energy emission. LCDs with lower energy emission may, therefore, serve as suitable screens to prevent light-induced retinal damage and protect consumers' eye health.


Assuntos
Luz , Cristais Líquidos/química , Células Fotorreceptoras de Vertebrados/patologia , Células Fotorreceptoras de Vertebrados/efeitos da radiação , Animais , Apoptose/efeitos da radiação , Caspase 3/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos da radiação , Inflamação/patologia , Camundongos , Mitocôndrias/patologia , Mitocôndrias/efeitos da radiação , NF-kappa B/metabolismo , Estresse Oxidativo/efeitos da radiação , Exposição à Radiação , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos da radiação
6.
ACS Appl Mater Interfaces ; 11(23): 20715-20724, 2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31144501

RESUMO

In recent years, photodynamic therapy (PDT) has drawn much attention as a noninvasive and safe cancer therapy method due to its fine controllability, good selectivity, low systemic toxicity, and minimal drug resistance in contrast to the conventional methods (for example, chemotherapy, radiotherapy, and surgery). However, some drawbacks still remain for the current organic photosensitizers such as low singlet oxygen (1O2) quantum yield, poor photostability, inability of absorption in the near-infrared (NIR) region, short excitation wavelength, and limited action radius of singlet oxygen, which will strongly limit the PDT treatment efficiency. As a consequence, the development of efficient photosensitizers with high singlet oxygen quantum yield, strong fluorescent emission in the aggregated state, excellent photostability, NIR excitation wavelength ranging in the biological transparency window, and highly specific targeting to mitochondria is still in great demand for the enhancement of PDT treatment efficiency. In this study, two new two-photon AIEgens TPPM and TTPM based on a rigid D-π-A skeleton have been designed and synthesized. Both AIEgens TPPM and TTPM show strong aggregation-induced emission (AIE) with the emission enhancement up to 290-folds, large two-photon absorption with the two-photon absorption cross section up to 477 MG, and highly specific targeting to mitochondria in living cells with good biocompatibility. They can serve as two-photon bioprobes for the cell and deep tissue bioimaging with a penetration depth up to 150 µm. Furthermore, high 1O2 generation efficiency with high 1O2 quantum yield under white light irradiation has been found for both TPPM and TTPM and high PDT efficiency to HeLa cells under white light irradiation has also been proven. To the best of our knowledge, AIEgens in this work constitute one of the strongest emission enhancements and one of the highest 1O2 generation efficiencies in the reported organic AIEgens so far. The great AIE feature, large two-photon absorption, high specificity to mitochondria in living cells, and high PDT efficiency to living cells as well as excellent photostability and biocompatibility of these novel AIEgens TPPM and TTPM reveal great potential in clinical applications of two-photon cell and tissue bioimaging and image-guided and mitochondria-targeted photodynamic cancer therapy.


Assuntos
Diagnóstico por Imagem/métodos , Luz , Mitocôndrias/efeitos da radiação , Fotoquimioterapia/métodos , Fótons , Animais , Células HeLa , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Fármacos Fotossensibilizantes/química
7.
Nat Cell Biol ; 21(6): 768-777, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31061466

RESUMO

Controlling cellular processes with light can help elucidate their underlying mechanisms. Here we present zapalog, a small-molecule dimerizer that undergoes photolysis when exposed to blue light. Zapalog dimerizes any two proteins tagged with the FKBP and DHFR domains until exposure to light causes its photolysis. Dimerization can be repeatedly restored with uncleaved zapalog. We implement this method to investigate mitochondrial motility and positioning in cultured neurons. Using zapalog, we tether mitochondria to constitutively active kinesin motors, forcing them down the axon towards microtubule (+) ends until their instantaneous release via blue light, which results in full restoration of their endogenous motility. We find that one-third of stationary mitochondria cannot be pulled away from their position and that these firmly anchored mitochondria preferentially localize to VGLUT1-positive presynapses. Furthermore, inhibition of actin polymerization with latrunculin A reduces this firmly anchored pool. On release from exogenous motors, mitochondria are preferentially recaptured at presynapses.


Assuntos
Axônios/metabolismo , Mitocôndrias/genética , Fotólise , Multimerização Proteica/efeitos da radiação , Actinas/antagonistas & inibidores , Animais , Axônios/química , Axônios/efeitos da radiação , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Células COS , Cinesina/química , Luz , Microtúbulos/genética , Microtúbulos/efeitos da radiação , Mitocôndrias/química , Mitocôndrias/efeitos da radiação , Neurônios/química , Neurônios/efeitos da radiação , Polimerização/efeitos dos fármacos , Domínios Proteicos/genética , Domínios Proteicos/efeitos da radiação , Multimerização Proteica/genética , Sinapses/química , Sinapses/genética , Sinapses/efeitos da radiação , Proteínas de Ligação a Tacrolimo/química , Proteínas de Ligação a Tacrolimo/genética , Tiazolidinas/farmacologia , Proteína Vesicular 1 de Transporte de Glutamato/genética
8.
Biomater Sci ; 7(7): 2812-2825, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31066391

RESUMO

Among brain tumors, glioblastoma multiforme (GBM) is the most common and aggressive form (WHO grade IV) with a median survival of only 14.6 months in adults. Photodynamic therapy (PDT) is a combination of a photosensitizer (PS), light and molecular oxygen, and considered a promising treatment for GBM. Therapeutic outcomes of PDT rely on ROS generation in a tumor microenvironment, which can be controlled with dual selectivity by localization of the photosensitizer and confinement of light to the targeted tumor microenvironment. We previously demonstrated the photodynamic anticancer efficacy of mitochondrial-targeted photosensitizer-loaded albumin nanoparticles (PS@chol-BSA NPs). In this study, the photodynamic therapeutic effect of PS@chol-BSA NPs was further enhanced by confinement of light using a fiber optic cannula in orthotopic GBM-xenografted mice. In vitro cellular uptake and phototoxicity of PS@chol-BSA NPs were evaluated in brain tumor (U87MG) and endothelial (bEnd.3) cells. In vivo biodistribution was determined by an in vivo imaging system (IVIS) and the photodynamic efficacy was evaluated with confined laser irradiation. PS@chol-BSA NPs showed higher cellular uptake and phototoxicity in U87MG cells than in bEnd.3 cells. PS@chol-BSA NPs showed a brain tumor accumulation of 0.2%ID within 2 h and remain in the brain tumor for 22 h. When compared to the control group, there was remarkable suppression in tumor growth by laser irradiation with and without the fiber optic cannula at a dose of 1 mg kg-1, in which significant tumor suppression up to 40% was observed with confined laser irradiation. Together, dual-selective photodynamic therapy with a mitochondria-targeted photosensitizer and fiber optic cannula provides a promising therapeutic strategy for malignant brain tumors.


Assuntos
Neoplasias Encefálicas/tratamento farmacológico , Cânula , Glioblastoma/tratamento farmacológico , Mitocôndrias/metabolismo , Fibras Ópticas , Fotoquimioterapia/instrumentação , Fármacos Fotossensibilizantes/farmacologia , Animais , Neoplasias Encefálicas/patologia , Bovinos , Linhagem Celular Tumoral , Portadores de Fármacos/química , Glioblastoma/patologia , Humanos , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/efeitos da radiação , Nanopartículas/química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacocinética , Soroalbumina Bovina/química , Distribuição Tecidual
9.
Ann Biomed Eng ; 47(7): 1564-1574, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30963380

RESUMO

The kidney is one of the most radiosensitive organs; it is the primary dose-limiting organ in radiotherapies for upper abdominal cancers. The role of mitochondrial redox state in the development and treatment of renal radiation injury, however, remains ill-defined. This study utilizes 3D optical cryo-imaging to quantify renal mitochondrial bioenergetics dysfunction after 13 Gy leg-out partial body irradiation (PBI). Furthermore, the mitigating effects of lisinopril (lisino), an anti-hypertensive angiotensin converting enzyme inhibitor, is assessed in renal radiation-induced injuries. Around day 150 post-irradiation, kidneys are harvested for cryo-imaging. The 3D images of the metabolic indices (NADH, nicotinamide adenine dinucleotide, and FAD, flavin adenine dinucleotide) are acquired, and the mitochondrial redox states of the irradiated and irradiated + lisino kidneys are quantified by calculating the volumetric mean redox ratio (NADH/FAD). PBI oxidized renal mitochondrial redox state by 78%. The kidneys from the irradiated + lisino rats showed mitigation of mitochondrial redox state by 93% compared to the PBI group. The study provides evidence for an altered bioenergetics and energy metabolism in the rat model of irradiation-induced kidney damage. In addition, the results suggest that lisinopril mitigates irradiation damage by attenuating the oxidation of mitochondria leading to increase redox ratio.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Nefropatias/tratamento farmacológico , Rim/efeitos da radiação , Lisinopril/uso terapêutico , Mitocôndrias/efeitos da radiação , Lesões por Radiação/tratamento farmacológico , Animais , Feminino , Flavina-Adenina Dinucleotídeo/metabolismo , Raios gama , Imagem Tridimensional , Rim/metabolismo , Nefropatias/metabolismo , Mitocôndrias/metabolismo , NAD/metabolismo , Lesões por Radiação/metabolismo , Ratos
10.
Blood Cells Mol Dis ; 77: 82-87, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31005751

RESUMO

Ionizing radiation (IR) causes severe damage to the hematopoietic system; thus, it is necessary to explore agents or compounds that can reduce this damage. SS31 is a mitochondria-targeted peptide that can scavenge cellular reactive oxygen species (ROS) and inhibit the production of mitochondrial ROS. Therefore, in this study, we discuss the protective effect of SS31 on IR-induced hematopoietic system damage. Our results showed that treatment with 6 mg/kg SS31 elevated the survival rate of lethally irradiated mice and increased the numbers of white blood cells, red blood cells, hemoglobin and platelets in mice exposed to 4 Gy whole-body irradiation. In addition, SS31 administration improved the number of hematopoietic stem/progenitor cells (HSPCs) and the self-renewal and reconstitution abilities of these cells in irradiated mice. The elevation of ROS levels is the main cause of IR-induced hematopoietic system damage, and SS31 can effectively reduce the ROS level in HSPCs. The above results suggest that SS31 can protect the hematopoietic system from radiation-induced damage by reducing cellular ROS levels.


Assuntos
Antioxidantes/farmacologia , Hematopoese/efeitos dos fármacos , Hematopoese/efeitos da radiação , Células-Tronco Hematopoéticas/efeitos dos fármacos , Células-Tronco Hematopoéticas/efeitos da radiação , Oligopeptídeos/farmacologia , Radiação Ionizante , Animais , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/efeitos da radiação , Modelos Animais de Doenças , Masculino , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitocôndrias/efeitos da radiação , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/efeitos da radiação , Doses de Radiação , Lesões Experimentais por Radiação/sangue , Lesões Experimentais por Radiação/mortalidade , Espécies Reativas de Oxigênio/metabolismo , Células-Tronco , Taxa de Sobrevida , Irradiação Corporal Total
11.
Int J Radiat Oncol Biol Phys ; 104(3): 644-655, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-30844421

RESUMO

PURPOSE: The impairment of the salivary glands is a permanent side effect of 131I ablation therapy for patients with differentiated thyroid cancer. Effective and safe treatments for protecting the salivary glands against 131I are currently not available. Mitochondria are susceptible to ionizing radiation, but alterations after 131I exposure are unknown. Here, we investigated the mechanisms of 131I damage in submandibular glands (SMGs) and evaluated the cytoprotective effect of phenylephrine (PE) against mitochondrial radiation damage. METHODS AND MATERIALS: Rats were randomly divided into 4 groups: control, PE alone, 131I alone, and 131I with PE pretreatment. The mitochondrial structure of SMGs was observed under transmission electron microscopy. Apoptosis was detected using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. Cytochrome c, cleaved-caspase 3, SIRT1, NAMPT, and PGC-1α protein levels were determined with Western blot and immunohistochemistry. Levels of mitochondrial membrane potential, nicotinamide adenine dinucleotide (NAD), and adenosine triphosphate (ATP) were measured with relevant kits. RESULTS: After exposing rat SMGs to 131I, the mitochondrial membrane structures were destroyed, the mitochondrial membrane potential decreased, the release of cytochrome c increased, and cleaved-caspase 3 and cell apoptosis were activated. Moreover, the expression of SIRT1, NAMPT, and PGC-1α was downregulated, and the levels of NAD and ATP decreased. In contrast, PE alleviated the 131I-induced mitochondrial damages and upregulated the expression of SIRT1/NAMPT/PGC-1α and the levels of NAD and ATP. CONCLUSIONS: These findings demonstrate that 131I impairs the salivary glands via the downregulation of SIRT1/NAMPT/PGC-1α signal pathways, which disturbs mitochondrial homeostasis. PE alleviated the 131I damage in SMGs at the mitochondrial level, suggesting that PE could be used as a potential radioprotector for patients with differentiated thyroid cancer with radiation sialadenitis.


Assuntos
Radioisótopos do Iodo/efeitos adversos , Mitocôndrias/efeitos da radiação , Fenilefrina/uso terapêutico , Lesões Experimentais por Radiação/prevenção & controle , Protetores contra Radiação/uso terapêutico , Glândula Submandibular/efeitos da radiação , Trifosfato de Adenosina/metabolismo , Trifosfato de Adenosina/efeitos da radiação , Animais , Apoptose/efeitos da radiação , Caspase 3/metabolismo , Caspase 3/efeitos da radiação , Citocromos c/metabolismo , Citocromos c/efeitos da radiação , Citocinas/metabolismo , Citocinas/efeitos da radiação , Regulação para Baixo , Homeostase , Marcação In Situ das Extremidades Cortadas , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Potencial da Membrana Mitocondrial/efeitos da radiação , Mitocôndrias/efeitos dos fármacos , NAD/metabolismo , NAD/efeitos da radiação , Nicotinamida Fosforribosiltransferase/metabolismo , Nicotinamida Fosforribosiltransferase/efeitos da radiação , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/efeitos da radiação , Lesões Experimentais por Radiação/metabolismo , Distribuição Aleatória , Ratos , Ratos Wistar , Sirtuína 1/metabolismo , Sirtuína 1/efeitos da radiação , Glândula Submandibular/ultraestrutura , Neoplasias da Glândula Tireoide/radioterapia
12.
Food Chem Toxicol ; 127: 19-30, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30844437

RESUMO

Hesperidin is a flavonoid which occurs in citrus fruits. Hesperidin was gamma-irradiated at doses of 0, 30, 70, and 150 kGy. Gamma irradiation induced a decreased hesperidin peak, and a new radiolytic peak that gradually increased up to 150 kGy. The new radiolytic peak was fractionated, and the fractionated hesperidin derivative was used for subsequent experiments. Hesperidin gamma-irradiated at 150 kGy was toxic toward B16BL6 cells, but not toward bone marrow-derived macrophages. This cytotoxicity was exerted via induction of apoptosis, as reflected by the high population of double-positive cells, increased sub-G1 phase cells, depolarization of matrix metalloproteinase, production of reactive oxygen species, weakness of cell adhesion, changes in cell morphology, and inhibition of B16BL6 cell migration. Furthermore, 150 kGy gamma-irradiated hesperidin decreased the expression of Bcl-2 and pro-caspases-3 and -9, increased the expression of Bax and cytosolic cytochrome c, and increased the cleavage of poly ADP ribose polymerase. In vitro mechanistic study revealed that 150 kGy gamma-irradiated hesperidin achieved significantly greater inhibition of lung metastasis and growth of melanoma B16BL6 cells in C57BL/6 mice than non-irradiated intact hesperidin did. These results suggest that the structural modification of hesperidin induced by gamma irradiation could facilitate the development of anti-cancer drugs.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Raios gama , Hesperidina/farmacologia , Melanoma Experimental/patologia , Metástase Neoplásica/prevenção & controle , Animais , Linhagem Celular Tumoral , Relação Dose-Resposta à Radiação , Hesperidina/química , Hesperidina/efeitos da radiação , Masculino , Metaloproteinases da Matriz/metabolismo , Melanoma Experimental/enzimologia , Melanoma Experimental/metabolismo , Camundongos Endogâmicos C57BL , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/efeitos da radiação , Estrutura Molecular , Espécies Reativas de Oxigênio/metabolismo , Relação Estrutura-Atividade
13.
J Photochem Photobiol B ; 194: 71-75, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30927704

RESUMO

Photobiomodulation (PBM) therapy is based on the use of specific light parameters to promote tissue repair. Although demonstrated in different cell models and tissues, the mechanism by which photobiomodulation operates is not well understood. Previous studies suggested that the cell proliferation enhancement triggered by red and near-infrared PBM involves the activation of the mitochondrial respiratory chain enzyme cytochrome c oxidase (CCO). It was suggested that light in this range would displace inhibitory nitric oxide bound to CCO. To test this mechanism, we took advantage of cell lines lacking CCO, including a mouse line knockout for Cox10 (a gene required for the synthesis of heme a, the prosthetic group of CCO) and a human cell line with an mtDNA mutation in the tRNA Lysine gene, leading to mitochondrial protein synthesis impairment and the lack of three critical CCO subunits. In both models we showed the complete absence of assembled CCO. PBM (660 nm) was applied to these proliferating cells using various parameters. In most of the conditions tested, increased cell proliferation was associated with PBM in both control and CCO negative cells, demonstrating that CCO is not required for PBM enhancement of cellular proliferation. Additional experiments showed that PBM increased both ATP levels and citrate synthase activity and levels. These results showed that although metabolic changes are associated with PBM, CCO is not required for its cell proliferation enhancing effect.


Assuntos
Proliferação de Células/efeitos da radiação , Terapia com Luz de Baixa Intensidade , Linhagem Celular , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Mitocôndrias/metabolismo , Mitocôndrias/efeitos da radiação
14.
Neurochem Int ; 125: 187-196, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30825600

RESUMO

Neurones are dependent on their mitochondria to produce the necessary amounts of ATP for survival. Retinal ganglion cells (RGCs) have a particularly large number of mitochondria which-unlike neurones in the brain-are exposed to visual light of 400-850 nm. Here we demonstrate that short wavelength visual blue light negatively affects mitochondrial function, causing oxidative stress and decreased cell survival. In contrast, long wavelength red light enhances mitochondrial function to increase survival of cultured R28 cells and reduce the effects of blue light. Induction of retinal ischemia for 60 min in dark conditions caused a reduction in ATP levels accompanied by decreased RGC numbers in all areas of the retina. These effects were diminished when ischemia was induced with concomitant delivery of red light, and exacerbated when blue light was used. We conclude that while the levels of blue light that reach the human retina will be a fraction of those used in the present study, the chronic nature might, on a theoretical basis, be detrimental to RGC mitochondria which are already affected by conditions such as glaucoma. Our findings also show that exposing the retina to red light may be a therapeutic approach to supporting healthy mitochondrial functions as part of the treatment for retinal diseases in which these organelles are affected.


Assuntos
Luz , Mitocôndrias/fisiologia , Mitocôndrias/efeitos da radiação , Células Ganglionares da Retina/fisiologia , Células Ganglionares da Retina/efeitos da radiação , Animais , Linhagem Celular , Sobrevivência Celular/fisiologia , Sobrevivência Celular/efeitos da radiação , Masculino , Ratos , Ratos Wistar , Retina/citologia , Retina/fisiologia , Retina/efeitos da radiação
15.
Nucleic Acids Res ; 47(8): 4026-4038, 2019 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-30715459

RESUMO

Eukaryotic Primase-Polymerase (PrimPol) is an enzyme that maintains efficient DNA duplication by repriming replication restart downstream of replicase stalling lesions and structures. To elucidate the cellular requirements for PrimPol in human cells, we generated PrimPol-deleted cell lines and show that it plays key roles in maintaining active replication in both the nucleus and mitochondrion, even in the absence of exogenous damage. Human cells lacking PrimPol exhibit delayed recovery after UV-C damage and increased mutation frequency, micronuclei and sister chromatin exchanges but are not sensitive to genotoxins. PrimPol is also required during mitochondrial replication, with PrimPol-deficient cells having increased mtDNA copy number but displaying a significant decrease in replication. Deletion of PrimPol in XPV cells, lacking functional polymerase Eta, causes an increase in DNA damage sensitivity and pronounced fork stalling after UV-C treatment. We show that, unlike canonical TLS polymerases, PrimPol is important for allowing active replication to proceed, even in the absence of exogenous damage, thus preventing the accumulation of excessive fork stalling and genetic mutations. Together, these findings highlight the importance of PrimPol for maintaining efficient DNA replication in unperturbed cells and its complementary roles, with Pol Eta, in damage tolerance in human cells.


Assuntos
Núcleo Celular/efeitos da radiação , DNA Primase/genética , Replicação do DNA/efeitos da radiação , DNA Polimerase Dirigida por DNA/genética , DNA/genética , Mitocôndrias/efeitos da radiação , Enzimas Multifuncionais/genética , 4-Nitroquinolina-1-Óxido/farmacologia , Bleomicina/farmacologia , Linhagem Celular Transformada , Linhagem Celular Tumoral , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/genética , Cisplatino/farmacologia , DNA/efeitos dos fármacos , DNA/metabolismo , DNA Primase/deficiência , Replicação do DNA/efeitos dos fármacos , DNA Polimerase Dirigida por DNA/deficiência , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fibroblastos/efeitos da radiação , Deleção de Genes , Humanos , Micronúcleos com Defeito Cromossômico/efeitos dos fármacos , Micronúcleos com Defeito Cromossômico/efeitos da radiação , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Enzimas Multifuncionais/deficiência , Mutagênicos/farmacologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Osteoblastos/efeitos da radiação , Quinolonas/farmacologia , Troca de Cromátide Irmã/efeitos dos fármacos , Troca de Cromátide Irmã/efeitos da radiação , Raios Ultravioleta/efeitos adversos
16.
Exp Mol Med ; 51(2): 14, 2019 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-30755594

RESUMO

Sublethal doses of γ-rays promote cancer cell invasion by stimulating a signaling pathway that sequentially involves p53, sulfatase 2 (SULF2), ß-catenin, interleukin-6 (IL-6), signal transducer and activator of transcription 3 (STAT3), and Bcl-XL. Given that Bcl-XL can increase O2•- production by stimulating respiratory complex I, the possible role of mitochondrial reactive oxygen species (ROS) in γ-irradiation-induced cell invasion was investigated. Indeed, γ-irradiation promoted cell invasion by increasing mitochondrial ROS levels, which was prevented by metformin, an inhibitor of complex I. γ-Irradiation-stimulated STAT3 increased the expression of superoxide dismutase 2 (SOD2), a mitochondrial enzyme that catalyzes the conversion of O2•- to hydrogen peroxide (H2O2). In contrast to O2•-, H2O2 functions as a signaling molecule. γ-Irradiation consistently stimulated the Src-dependent invasion pathway in a manner dependent on both complex I and SOD2. SOD2 was also essential for the invasion of un-irradiated cancer cells induced by upregulation of Bcl-XL, an intracellular oncogene, or extracellular factors, such as SULF2 and IL-6. Overall, these data suggested that SOD2 is critical for the malignant effects of radiotherapy and tumor progression through diverse endogenous factors.


Assuntos
Raios gama , Mitocôndrias/metabolismo , Mitocôndrias/efeitos da radiação , Superóxido Dismutase/metabolismo , Biomarcadores , Linhagem Celular Tumoral , Movimento Celular/genética , Expressão Gênica , Humanos , Interleucina-6/metabolismo , Mitocôndrias/genética , Estresse Oxidativo , Fosforilação , Tolerância a Radiação/genética , Espécies Reativas de Oxigênio/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Superóxido Dismutase/genética , Quinases da Família src/genética , Quinases da Família src/metabolismo
17.
New Phytol ; 222(3): 1364-1379, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30636322

RESUMO

Photoacclimation consists of short- and long-term strategies used by photosynthetic organisms to adapt to dynamic light environments. Observable photophysiology changes resulting from these strategies have been used in coarse-grained models to predict light-dependent growth and photosynthetic rates. However, the contribution of the broader metabolic network, relevant to species-specific strategies and fitness, is not accounted for in these simple models. We incorporated photophysiology experimental data with genome-scale modeling to characterize organism-level, light-dependent metabolic changes in the model diatom Phaeodactylum tricornutum. Oxygen evolution and photon absorption rates were combined with condition-specific biomass compositions to predict metabolic pathway usage for cells acclimated to four different light intensities. Photorespiration, an ornithine-glutamine shunt, and branched-chain amino acid metabolism were hypothesized as the primary intercompartment reductant shuttles for mediating excess light energy dissipation. Additionally, simulations suggested that carbon shunted through photorespiration is recycled back to the chloroplast as pyruvate, a mechanism distinct from known strategies in photosynthetic organisms. Our results suggest a flexible metabolic network in P. tricornutum that tunes intercompartment metabolism to optimize energy transport between the organelles, consuming excess energy as needed. Characterization of these intercompartment reductant shuttles broadens our understanding of energy partitioning strategies in this clade of ecologically important primary producers.


Assuntos
Diatomáceas/metabolismo , Diatomáceas/efeitos da radiação , Luz , Aclimatação/efeitos da radiação , Oxirredutases do Álcool/metabolismo , Biomassa , Respiração Celular/efeitos da radiação , Ritmo Circadiano/efeitos da radiação , Simulação por Computador , Transporte de Elétrons/efeitos da radiação , Redes e Vias Metabólicas/efeitos da radiação , Mitocôndrias/metabolismo , Mitocôndrias/efeitos da radiação , Modelos Biológicos , Fotossíntese/efeitos da radiação , Ácido Pirúvico/metabolismo
18.
Health Phys ; 116(4): 454-472, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30681424

RESUMO

The acute radiation syndrome of the gastrointestinal tract has been histologically characterized, but the molecular and functional mechanisms that lead to these cellular alterations remain enigmatic. Mass spectrometry imaging is the only technique that enables the simultaneous detection and cellular or regional localization of hundreds of biomolecules in a single experiment. This current study utilized matrix-assisted laser desorption/ionization mass spectrometry imaging for the molecular characterization of the first natural history study of gastrointestinal acute radiation syndrome in the nonhuman primate. Jejunum samples were collected at days 4, 8, 11, 15, and 21 following 12-Gy partial-body irradiation with 2.5% bone marrow sparing. Mass spectrometry imaging investigations identified alterations in lipid species that further understanding of the functional alterations that occur over time in the different cellular regions of the jejunum following exposure to high doses of irradiation. Alterations in phosphatidylinositol species informed on dysfunctional epithelial cell differentiation and maturation. Differences in glycosphingolipids of the villi epithelium that would influence the absorptive capacity and functional structure of the brush border membrane were detected. Dichotomous alterations in cardiolipins indicated altered structural and functional integrity of mitochondria. Phosphatidylglycerol species, known regulators of toll-like receptors, were detected and localized to regions in the lamina propria that contained distinct immune cell populations. These results provide molecular insight that can inform on injury mechanism in a nonhuman primate model of the acute radiation syndrome of the gastrointestinal tract. Findings may contribute to the identification of therapeutic targets and the development of new medical countermeasures.


Assuntos
Síndrome Aguda da Radiação/patologia , Trato Gastrointestinal/efeitos da radiação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Síndrome Aguda da Radiação/metabolismo , Animais , Biomarcadores , Trato Gastrointestinal/metabolismo , Trato Gastrointestinal/patologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Mucosa Intestinal/efeitos da radiação , Jejuno/metabolismo , Jejuno/patologia , Jejuno/efeitos da radiação , Metabolismo dos Lipídeos/efeitos da radiação , Macaca mulatta , Masculino , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Mitocôndrias/efeitos da radiação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos
19.
Appl Microbiol Biotechnol ; 103(4): 1851-1864, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30661110

RESUMO

Mitochondrial dysfunction in Saccharomyces cerevisiae was selected as a marker of ion penetration following carbon ion beam (CIB) irradiation. Respiration-deficient mutants were screened. Following confirmation of negligible spontaneous mutation, eight genetically stable S. cerevisiae respiration-deficient mutant strains and a control strain were resequenced with ~ 200-fold read depth. Strategies were established to identify and validate the particular mutations induced by CIB irradiation. In the nuclear genome, CIB irradiation mainly caused base substitutions and some small (< 100 bp) insertions/deletions (indels), which were widely distributed across the chromosomes. Although mitochondrial dysfunction was selected as a screening marker, variants in the nuclear genome were detected at a high frequency (10-7) relative to spontaneous mutations (10-9). The transition to transversion ratio for base substitutions was 0.746, which was less than that of spontaneous mutations. In the mitochondrial genome, there were very large deletions including substantial gene areas, resulting in extremely low read coverage. Meanwhile, every mutant possessed a distinctive mutation pattern, for both the nuclear and the mitochondrial genome. Nuclear genomes contained scanty mitochondrial respiration-related genes that were potentially affected by verified mutations, suggesting that variants in the mitochondrial genome may be the main drivers of respiratory deficiencies. Our study confirmed the previous finding that heavy ion beam (HIB) irradiation mainly induces substantial base substitutions and some small indels but also yielded some novel findings, in particular, novel structural variants in the mitochondrial genomes. These data will enhance the understanding of HIB-induced damage and mutations and aid in the HIB-based microbial mutation breeding.


Assuntos
Carbono/metabolismo , Íons/metabolismo , Mitocôndrias/efeitos da radiação , Mutação , Fosforilação Oxidativa/efeitos da radiação , Saccharomyces cerevisiae/efeitos da radiação , Análise Mutacional de DNA , Genoma Fúngico , Mutagênese , Análise de Sequência de DNA
20.
Methods Mol Biol ; 1880: 611-619, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30610726

RESUMO

One can utilize light illumination to stimulate mitochondrial reactive oxygen species production through the use of mitochondria-specific photosensitizers. By proper tuning of the light dosage, the methodology permits probing of a multitude of mitochondrial damage responses, including mitophagy. This light-controllable trick offers unique opportunities for the investigation of mitophagy-one can spatiotemporally define mitochondrial damage, alter the number of impaired mitochondria, as well as modulate the severity of the mitochondrial injury. This light-activated mitophagy can be adapted not only to single-cell imaging techniques but also to cell population-based biochemical assays.


Assuntos
Luz/efeitos adversos , Fármacos Fotossensibilizantes/farmacologia , Células HeLa , Humanos , Microscopia Intravital/instrumentação , Microscopia Intravital/métodos , Microscopia Confocal/instrumentação , Microscopia Confocal/métodos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/efeitos da radiação , Espécies Reativas de Oxigênio/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
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