scholarly journals Inhibition of de novo ceramide biosynthesis affects aging phenotype in an in vitro model of neuronal senescence

2019 ◽  
Author(s):  
Alberto Granzotto ◽  
Manuela Bomba ◽  
Vanessa Castelli ◽  
Riccardo Navarra ◽  
Noemi Massetti ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Mitochondrial Dysfunction ◽  
Cellular Senescence ◽  
Cortical Neurons ◽  
De Novo ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Synaptic Activity ◽  
Oxygen Species

AbstractAlthough aging is considered to be an unavoidable event, recent experimental evidence suggests that the process can be delayed, counteracted, if not completely interrupted. Aging is the primary risk factor for the onset and development of neurodegenerative conditions like Alzheimer’s disease, Parkinson’s disease, and Amyotrophic Lateral Sclerosis. Intracellular calcium (Ca2+i) dyshomeostasis, mitochondrial dysfunction, oxidative stress, and lipid dysregulation are critical factors that contribute to senescence-related processes. Ceramides, a class of sphingolipids involved in a wide array of biological functions, are important mediators of cellular senescence, but their role in neuronal aging is still largely unexplored.In this study, we investigated the effects of L-cycloserine (L-CS), an inhibitor of de novo ceramide biosynthesis, on the aging phenotype of cortical neurons that have been maintained in culture for 22 days, a setting employed as an in vitro model of cellular senescence. Our findings indicate that ‘aged’ neurons display, when compared to control cultures, overt dysregulation of cytosolic and subcellular [Ca2+]i levels, mitochondrial dysfunction, increased reactive oxygen species generation, altered synaptic activity as well as the activation of neuronal death-related molecules. Treatment with L-CS (30 µM) positively affected the senescent phenotype, a result accompanied by recovery of neuronal [Ca2+]i signaling, and reduction of mitochondrial dysfunction and reactive oxygen species generation.The results suggest that the de novo ceramide biosynthesis may represent a critical intermediate in the molecular and functional cascade leading to neuronal senescence. Our findings also identify ceramide biosynthesis inhibitors as promising pharmacological tools to decrease age-related neuronal dysfunctions.

Novel Tetrazoles against Acanthamoeba castellanii Belonging to the T4 Genotype

Chemotherapy ◽  
2021 ◽  
Author(s):  
Yassmin Isse Wehelie ◽  
Naveed Ahmed Khan ◽  
Itrat Fatima ◽  
Areeba Anwar ◽  
Kanwal Kanwal ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Silver Nanoparticles ◽  
Reactive Oxygen Species Generation ◽  
Acanthamoeba Castellanii ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Species Determination ◽  
One Pot ◽  
Tetrazole Derivatives

Background: Acanthamoeba castellanii is a pathogenic free-living amoeba responsible for blinding keratitis and fatal granulomatous amoebic encephalitis. However, treatments are not standardized but can involve the use of amidines, biguanides, and azoles. Objectives: The aim of this study was to synthesize a variety of synthetic tetrazole derivatives and test their activities against A. castellanii. Methods: A series of novel tetrazole compounds were synthesized by one-pot method and characterized by NMR and mass spectroscopy. These compounds were subjected to amoebicidal, and cytotoxicity assays against A. castellanii belonging to the T4 genotype and human keratinocyte skin cells respectively. Additionally, reactive oxygen species determination and electron microscopy studies were carried out. Furthermore, two of the seven compounds were conjugated with silver nanoparticles to study their antiamoebic potential. Results: A series of seven tetrazole derivatives were synthesized successfully. The selected tetrazoles showed anti-amoebic activities at 10µM concentration against A. castellanii in vitro. The compounds tested caused increased reactive oxygen species generation in A castellanii, and significant morphological damage to amoebal membranes. Moreover, conjugation of silver nanoparticles enhanced antiamoebic effects of two tetrazoles. Conclusions: The results showed that azole compounds hold promise in the development of new formulations of anti-Acanthamoebic agents.

scholarly journals Plasmonic Hot-Electron Reactive Oxygen Species Generation: Fundamentals for Redox Biology

2020 ◽  
Vol 8 ◽  
Author(s):  
Elisa Carrasco ◽  
Juan Carlos Stockert ◽  
Ángeles Juarranz ◽  
Alfonso Blázquez-Castro
Keyword(s):  
Reactive Oxygen Species ◽  
Near Infrared ◽  
Chemical Reactivity ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Ros Generation ◽  
Oxygen Species ◽  
Hot Electron ◽  
Redox Biology

For decades, the possibility to generate Reactive Oxygen Species (ROS) in biological systems through the use of light was mainly restricted to the photodynamic effect: the photoexcitation of molecules which then engage in charge- or energy-transfer to molecular oxygen (O2) to initiate ROS production. However, the classical photodynamic approach presents drawbacks, like per se chemical reactivity of the photosensitizing agent or fast molecular photobleaching due to in situ ROS generation, to name a few. Recently, a new approach, which promises many advantages, has entered the scene: plasmon-driven hot-electron chemistry. The effect takes advantage of the photoexcitation of plasmonic resonances in metal nanoparticles to induce a new cohort of photochemical and redox reactions. These metal photo-transducers are considered chemically inert and can undergo billions of photoexcitation rounds without bleaching or suffering significant oxidative alterations. Also, their optimal absorption band can be shape- and size-tailored in order to match any of the near infrared (NIR) biological windows, where undesired absorption/scattering are minimal. In this mini review, the basic mechanisms and principal benefits of this light-driven approach to generate ROS will be discussed. Additionally, some significant experiments in vitro and in vivo will be presented, and tentative new avenues for further research will be advanced.

scholarly journals Triptolide suppresses IDH1-mutated malignancy via Nrf2-driven glutathione metabolism

2020 ◽  
Vol 117 (18) ◽  
pp. 9964-9972 ◽  
Author(s):  
Di Yu ◽  
Yang Liu ◽  
Yiqiang Zhou ◽  
Victor Ruiz-Rodado ◽  
Mioara Larion ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
De Novo ◽  
Synthetic Lethality ◽  
Reactive Oxygen ◽  
Metabolic Reprogramming ◽  
Glutathione Metabolism ◽  
Oxygen Species ◽  
Genetic Abnormality

Isocitrate dehydrogenase (IDH) mutation is a common genetic abnormality in human malignancies characterized by remarkable metabolic reprogramming. Our present study demonstrated that IDH1-mutated cells showed elevated levels of reactive oxygen species and higher demands on Nrf2-guided glutathione de novo synthesis. Our findings showed that triptolide, a diterpenoid epoxide from Tripterygium wilfordii, served as a potent Nrf2 inhibitor, which exhibited selective cytotoxicity to patient-derived IDH1-mutated glioma cells in vitro and in vivo. Mechanistically, triptolide compromised the expression of GCLC, GCLM, and SLC7A11, which disrupted glutathione metabolism and established synthetic lethality with reactive oxygen species derived from IDH1 mutant neomorphic activity. Our findings highlight triptolide as a valuable therapeutic approach for IDH1-mutated malignancies by targeting the Nrf2-driven glutathione synthesis pathway.

Reactive Oxygen Species Target the Degradation of the EVI1 Oncoprotein.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 651-651
Author(s):  
David Shackelford ◽  
You Wang ◽  
Samuel Waxman ◽  
Ruibao Ren
Keyword(s):  
Reactive Oxygen Species ◽  
De Novo ◽  
Bone Marrow Cells ◽  
Reactive Oxygen ◽  
Myelogenous Leukemia ◽  
Leukemic Cells ◽  
Mouse Bone Marrow ◽  
Oxygen Species ◽  
Aberrant Expression

Abstract Aberrant expression of EVI1 has been frequently found in myeloid malignancies as well as in cancers of the ovary, lung, head and neck, cervix, and breast, and is associated with a poor patient survival. Targeted degradation of oncoproteins is an effective strategy for cancer therapy. The AML1/MDS1/EVI1 (AME) transcription factor fusion protein is a product of the human t(3;21)(q26;q22) translocation found as a secondary mutation in some cases of CML during the blast phase (CML-BP) and in patients with de novo and therapy-related myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML). Expression of AME in mouse bone marrow cells by retroviral transduction impairs hematopoiesis and eventually induces an acute myeloid leukemia (AML)-like disease in mice. Arsenic Trioxide (ATO) has been found to be an effective treatment for patients suffering from acute promyelocytic leukemia (APL). This is, at least in part, mediated by degradation of the PML/RARα oncoprotein that is associated with over 90% of APL. We have recently shown that ATO used at therapeutic levels also degrades AME. The ATO treatment induces differentiation and apoptosis in AME leukemic cells in vitro and causes decrease in peripheral leukemic cells and splenomegaly in vivo. ATO appears to target AME at both the EVI1 and MDS moieties of the protein for degradation via the ubiquitin-proteasome pathway and proteasome-independent mechanism, respectively. To investigate the mechanism of ATO induced degradation of EVI1 oncoproteins, we examined the effect of reactive oxygen species (ROS), on EVII expression, one of the downstream effectors of ATO-induced apoptosis. We found that EVI1 degradation correlates with the amount of ROS generated in cells. EVI1 can also be targeted for degradation by doxorubicin, a chemotherapeutic agent that is effective in treating AML and ovarian cancer and a strong ROS inducer. Interestingly, the antioxidant N-acetyl cysteine (NAC) abrogates the degradation of the EVI1 protein in the presence of doxorubicin. These results demonstrate that EVI1 can be targeted for degradation by ROS. ROS inducing agents could be used as a part of targeted therapy for EVI1-positive malignancies.

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