scholarly journals Landomycins as glutathione-depleting agents and natural fluorescent probes for cellular Michael adduct-dependent quinone metabolism

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Alessio Terenzi ◽  
Mery La Franca ◽  
Sushilla van Schoonhoven ◽  
Rostyslav Panchuk ◽  
Álvaro Martínez ◽  
...  
Keyword(s):  
Reduced Glutathione ◽  
Fluorescence Probes ◽  
Dependent Manner ◽  
Label Free ◽  
Blue Fluorescence ◽  
Michael Adduct ◽  
Michael Adducts ◽  
Oligosaccharide Chain ◽  
Sh Group ◽  
Reduced Activity

AbstractLandomycins are angucyclines with promising antineoplastic activity produced by Streptomyces bacteria. The aglycone landomycinone is the distinctive core, while the oligosaccharide chain differs within derivatives. Herein, we report that landomycins spontaneously form Michael adducts with biothiols, including reduced cysteine and glutathione, both cell-free or intracellularly involving the benz[a]anthraquinone moiety of landomycinone. While landomycins generally do not display emissive properties, the respective Michael adducts exerted intense blue fluorescence in a glycosidic chain-dependent manner. This allowed label-free tracking of the short-lived nature of the mono-SH-adduct followed by oxygen-dependent evolution with addition of another SH-group. Accordingly, hypoxia distinctly stabilized the fluorescent mono-adduct. While extracellular adduct formation completely blocked the cytotoxic activity of landomycins, intracellularly it led to massively decreased reduced glutathione levels. Accordingly, landomycin E strongly synergized with glutathione-depleting agents like menadione but exerted reduced activity under hypoxia. Summarizing, landomycins represent natural glutathione-depleting agents and fluorescence probes for intracellular anthraquinone-based angucycline metabolism.

scholarly journals Prostaglandin A1 inhibits the phosphorylation of tau via activating protein phosphotase 2A in a michael addition mechanism at the site of cysteine 377

2020 ◽  
Author(s):  
Guo-Biao Xu ◽  
Pei-Pei Guan ◽  
Pu Wang
Keyword(s):  
Cognitive Decline ◽  
Michael Addition ◽  
Dependent Manner ◽  
Western Blots ◽  
Michael Adduct ◽  
Term Administration ◽  
Prostaglandin A1

Abstract Background: Prostaglandin (PG) A1 is a metabolic product of cyclooxygenase 2 (COX-2), which potentially involved in regulating the development and progression of Alzheimer’s disease (AD). As a cyclopentenone (cy) PG, PGA1 is characterized by the presence of a chemically reactive α, β-unsaturated carbonyl. Although PGA1 is potentially involved in regulating multiple biological processes via michael addition, its specific roles in AD remained unclear.Methods: The tauP301S transgenic (Tg) mice were employed as in vivo AD models and neuroblastoma (N) 2a cells as in vitro neuronal models. By intracerebroventricular injected (i.c.v) with PGA1, the binding proteins to PGA1 are analyzed by HPLC-MS-MS. In addition, western blots are used to determine the phosphorylation of tau in PGA1 treated Tg mice in the absence or presence of okadaic acid (OA), an inhibitor of protein phosphotase (PP) 2A. Combining a synthesis of pull down assay, immunoprecipitation, western blots and HPLC-MS-MS, PP2A scaffold subunit A alpha (PPP2R1A) was identified to be activated by directly binding on PGA1 in cysteine 377-dependent manner. Via inhibiting the hyperphosphorylation of tau, morris maze test was employed to determine the inhibitory effects of PGA1 on cognitive decline of tauP301S Tg mice.Results: By incubation with neuroblastoma (n)2a cells and pull down assay, mass spectra (MS) analysis revealed that PGA1 binds with more than 1000 proteins, among which contains the proteins of AD, especially tau protein. Moreover, short-term administration of PGA1 to tauP301S Tg mice significantly decreased the phosphorylation of tau at the sites of Thr181, Ser202 and Ser404 in a dose-dependent manner. To the reason, it’s caused by activating PPP2R1A in tauP301S Tg mice. More importantly, PGA1 has the ability to form michael adduct with PPP2R1A via its cysteine 377 motif, which is critical for the enzymatic activity of PP2A. By activating PP2A, long-term application of PGA1 to tauP301S Tg mice significantly reduced the phosphorylation of tau, which results in improving the cognitive decline of tauP301S Tg mice.Conclusion: Our data provided the first insights needed to decipher the mechanisms underlying the ameliorating effects of PGA1 on cognitive decline of tauP301S Tg mice via activating PP2A in a PPP2R1AC377-dependent Michael adducting mechanisms.

Oxidative stress biomarkers in the gills of the bivalve Mactra stultorum exposed to acrylamide

2020 ◽  
Vol 84 (2) ◽  
Author(s):  
Wafa Trabelsi ◽  
Chaima Fouzai ◽  
Imene Chetoui ◽  
Safa Bejaoui ◽  
Khaoula Telahigue ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Ache Activity ◽  
Reduced Glutathione ◽  
Lipid Hydroperoxides ◽  
Dependent Manner ◽  
Advanced Oxidation Protein Products ◽  
Oxidative Stress Biomarkers ◽  
Stress Biomarkers ◽  
The Subject ◽  
Dose Dependent

Acrylamide (ACR) is among the most deleterious pollutants in the environment and presents a serious risk to humans and ecosystems. The purpose of this study was to assess its effects when administered at different concentrations (5, 10 and 20 mg L–1) to evaluate antioxidant status in the gills of Mactra stultorum. Our results showed, after five days of treat­ment, an increase in malondialdehyde (MDA), lipid hydroperoxides (LOOH), advanced oxidation protein products (AOPP), reduced glutathione (GSH), ascorbic acid (Vit C) and metallothionein (MDA) levels in gills of treated clams compared with controls. Moreover, an increase in superoxide dismutase (SOD) and a significant decrease in glutathione peroxidase (GPx) activities were also observed. Acrylamide induced neurotoxicity, as evidenced by the inhibition of acetylcholinesterase (AChE) activity in a dose-dependent manner. Overall, our results indicated that oxidative stress may be considered one of the mechanisms behind acrylamide toxicity in bivalves, although the subject requires more research.

scholarly journals Minocycline reduces inflammatory response and cell death in a S100B retina degeneration model

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Pia Grotegut ◽  
Natarajan Perumal ◽  
Sandra Kuehn ◽  
Andreas Smit ◽  
H. Burkhard Dick ◽  
...  
Keyword(s):  
Cell Death ◽  
Body Weight ◽  
Optic Nerve ◽  
Inflammatory Response ◽  
Negative Impact ◽  
Dependent Manner ◽  
Label Free ◽  
Proteomics Analysis ◽  
Concentration Dependent Manner ◽  
Minocycline Treatment

Abstract Background Previous studies noted that intravitreal injection of S100B triggered a glaucoma-like degeneration of retina and optic nerve as well as microglia activation after 14 days. The precise role of microglia in our intravitreal S100B model is still unclear. Hence, microglia were inhibited through minocycline. The aim is to investigate whether microglia have a significant influence on the degeneration process or whether they are only a side effect in the model studied here. Methods Minocycline was applied daily in rats by intraperitoneal injection using two different concentrations (13.5 mg/kg body weight, 25 mg/kg body weight). One day after treatment start, S100B or PBS was intravitreally injected in one eye per rat. The naïve groups received no injections. This resulted in a total of five groups (naïve n = 14, PBS n = 14, S100B n = 13, 13.5 mg/kg mino n = 15, 25 mg/kg mino n = 15). At day 14, electroretinogram measurements were performed, followed by immunofluorescence and label-free quantitative proteomics analysis. The focus of these investigations was on the survival of RGCs as well as their axons, the response of the microglia, and the identification of further pathological modes of action of S100B. Results The best signal transmission was detected via ERG in the 13.5 mg/kg mino group. The inhibition of the microglia protected optic nerve neurofilaments and decreased the negative impact of S100B on RGCs. However, the minocycline treatment could not trigger complete protection of RGCs. Furthermore, in retina and optic nerve, the minocycline treatment reduced the number and activity of S100B-triggered microglia in a concentration-dependent manner. Proteomics analysis showed that S100B application led to numerous metabolic functions and cellular stress, mainly an increased inflammatory response, glycolysis, and mitochondrial dysfunction, which caused oxidative stress in the retina. Importantly, the protective capability of lower dose of minocycline was unraveled by suppressing the apoptotic, inflammatory, and the altered metabolic processes caused by S100B insult in the retina. Conclusion Intravitreally injected S100B not only led to a pro-inflammatory microglial reaction, but also a mitochondrial and metabolic dysfunction. Also, these results suggest that an excessive microglial response may be a significant degenerative factor, but not the only trigger for increased cell death.

Tolbutamide inhibits glucagon-induced phosphorylation of 6PF-2-K/Fru-2,6-P2ase in rat hepatocytes

1995 ◽  
Vol 268 (3) ◽  
pp. E391-E396
Author(s):  
H. Ayame ◽  
A. Matsutani ◽  
H. Inoue ◽  
T. Kaneko ◽  
K. Kaku
Keyword(s):  
Rat Hepatocytes ◽  
Bifunctional Enzyme ◽  
Dependent Manner ◽  
Enzyme Protein ◽  
Dependent Protein ◽  
Sulfonylurea Drugs ◽  
Dose Dependent ◽  
Increased Activity ◽  
Reduced Activity

In previous studies, we demonstrated that tolbutamide inhibits a phosphorylation of hepatic 6-phosphofructo-2-kinase (6PF-2-K)/fructose-2,6-bisphosphatase (Fru-2,6-P2ase) catalyzed by the adenosine 3',5'-cyclic monophosphate-dependent protein kinase in a reconstruction system using the purified enzyme from the rat liver. In the current study, to assess a role of tolbutamide on hepatic 6PF-2-K/Fru-2,6-P2ase physiologically, we used intact rat hepatocytes and examined effects of tolbutamide on a phosphorylation of the bifunctional enzyme in the presence of glucagon. Glucagon induced a rapid phosphorylation of hepatic 6PF-2-K/Fru-2,6-P2ase accompanied by an inhibition of 6PF-2-K activity and a stimulation of Fru-2,6-P2ase activity in a dose-dependent manner. Tolbutamide inhibited glucagon-induced phosphorylation of the bifunctional enzyme protein in a dose-dependent manner. By adding 2 mM tolbutamide, reduced activity of 6PF-2-K and increased activity of Fru-2,6-P2ase in the presence of 10(-9) M glucagon were partially restored. The present results suggest the possibility that tolbutamide modulates the activity of hepatic 6PF-2-K/Fru-2,6-P2ase through inhibiting a phosphorylation of the enzyme protein. The counterregulatory influence of tolbutamide on the effect of glucagon suggests a possible mechanism for the extrapancreatic effect of sulfonylurea drugs.

scholarly journals PHARMACOLOGICAL ACTIVITY OF ULVA LACTUCA POLYPHENOLS FRACTION: CARDIOPROTECTIVE AND ANTIOXIDANT ACTIVITIES AGAINST ISOPROTERENOL-INDUCED MYOCARDIAL INFARCTION IN RATS

2019 ◽  
pp. 133-136
Author(s):  
RAVINDRAN NT ◽  
MOHAMED SADIQ A
Keyword(s):  
Myocardial Infarction ◽  
Antioxidant Activities ◽  
Reduced Glutathione ◽  
Serum Markers ◽  
Ulva Lactuca ◽  
Albino Rats ◽  
High Dose ◽  
Dependent Manner ◽  
Wistar Albino Rats ◽  
Antioxidant Markers

Objective: The objective of this study is to assess the activity of Ulva lactuca polyphenols fraction in protecting the myocardial infarction induced by a high dose of isoproterenol. Methods: This study was carried out using Wistar albino rats divided into six groups. Group 1 was the normal group. Groups 2, 3, 4, 5, and 6 received isoproterenol (85 mg/kg) i.p. twice at an interval of 24 h on the 14th and 15th day. In addition to isoproterenol, Group 3 received verapamil (5 μmol/kg) as a single dose intravenously on the 14th day 10 min before isoproterenol and Groups 4, 5, and 6 received U. lactuca polyphenols fraction at the doses of 50, 100, and 200 mg/kg, respectively, for 14 days. On the 16th day, serum and heart samples were harvested from the animals and the cardioprotective and antioxidant activities were assessed by studying the levels of cardiac functional heart marker enzymes, lipid profile, reduced glutathione, and antioxidant enzymes. Results: U. lactuca polyphenols fraction, at the tested doses, restored the levels of all serum markers and enzymes (aspartate aminotransferase, alanine aminotransferase, creatine phosphokinase, lactate dehydrogenase, cholesterol, triglycerides, and reduced glutathione) and heart homogenate antioxidant markers (reduced glutathione, superoxide dismutase, catalase, and glutathione peroxidase) significantly, in dose-dependent manner. Conclusion: This study suggests that U. lactuca polyphenols fraction has a cardioprotective effect against isoproterenol-induced myocardial infarction and possess antioxidant activities.

scholarly journals Zebrafish structural development in Mueller-matrix scanning microscopy

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Aymeric Le Gratiet ◽  
Marta d’Amora ◽  
Marti Duocastella ◽  
Riccardo Marongiu ◽  
Artemi Bendandi ◽  
...  
Keyword(s):  
Structural Changes ◽  
Molecular Mechanisms ◽  
Developmental Stages ◽  
Mueller Matrix ◽  
Fluorescence Probes ◽  
Imaging Method ◽  
Structural Development ◽  
Matrix Formalism ◽  
Label Free ◽  
Biological Organization

AbstractZebrafish are powerful animal models for understanding biological processes and the molecular mechanisms involved in different human diseases. Advanced optical techniques based on fluorescence microscopy have become the main imaging method to characterize the development of these organisms at the microscopic level. However, the need for fluorescence probes and the consequent high light doses required to excite fluorophores can affect the biological process under observation including modification of metabolic function or phototoxicity. Here, without using any labels, we propose an implementation of a Mueller-matrix polarimeter into a commercial optical scanning microscope to characterize the polarimetric transformation of zebrafish preserved at different embryonic developmental stages. By combining the full polarimetric measurements with statistical analysis of the Lu and Chipman mathematical decomposition, we demonstrate that it is possible to quantify the structural changes of the biological organization of fixed zebrafish embryos and larvae at the cellular scale. This convenient implementation, with low light intensity requirement and cheap price, coupled with the quantitative nature of Mueller-matrix formalism, can pave the way for a better understanding of developmental biology, in which label-free techniques become a standard tool to study organisms.

scholarly journals Labeled vs. Label-Free Raman Imaging of Lipids in Endothelial Cells of Various Origins

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5752
Author(s):  
Basseem Radwan ◽  
Adriana Adamczyk ◽  
Szymon Tott ◽  
Krzysztof Czamara ◽  
Katarzyna Kaminska ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Endothelial Cells ◽  
Lipid Content ◽  
Single Layer ◽  
Vascular Diseases ◽  
Raman Imaging ◽  
Dependent Manner ◽  
Label Free ◽  
Necrosis Factor Alpha ◽  
Cellular Lipids

Endothelial cells (EC) constitute a single layer of the lining of blood vessels and play an important role in maintaining cardiovascular homeostasis. Endothelial dysfunction has been recognized as a primary or secondary cause of many diseases and it manifests itself, among others, by increased lipid content or a change in the lipid composition in the EC. Therefore, the analysis of cellular lipids is crucial to understand the mechanisms of disease development. Tumor necrosis factor alpha (TNF-α)-induced inflammation of EC alters the lipid content of cells, which can be detected by Raman spectroscopy. By default, lipid detection is carried out in a label-free manner, and these compounds are recognized based on their spectral profile characteristics. We consider (3S,3′S)-astaxanthin (AXT), a natural dye with a characteristic resonance spectrum, as a new Raman probe for the detection of lipids in the EC of various vascular beds, i.e., the aorta, brain and heart. AXT colocalizes with lipids in cells, enabling imaging of lipid-rich cellular components in a time-dependent manner using laser power 10 times lower than that commonly used to measure biological samples. The results show that AXT can be used to study lipids distribution in EC at various locations, suggesting its use as a universal probe for studying cellular lipids using Raman spectroscopy. The use of labeled Raman imaging of lipids in the EC of various organs could contribute to their easier identification and to a better understanding of the development and progression of various vascular diseases, and it could also potentially improve their diagnosis and treatment.

Protective Effect of Reduced Glutathione against CIS-Dichlorodiammine Platinum (II)–Induced Nephrotoxicity and Lethal Toxicity

1983 ◽  
Vol 69 (2) ◽  
pp. 105-111 ◽  
Author(s):  
Franco Zunino ◽  
Odoardo Tofanetti ◽  
Adriana Besati ◽  
Ennio Cavalletti ◽  
Giuseppina Savi
Keyword(s):  
Reduced Glutathione ◽  
Body Weight Loss ◽  
Dependent Manner ◽  
Sprague Dawley ◽  
Antitumor Effects ◽  
Partial Protection ◽  
Lethal Toxicity ◽  
Sprague Dawley Rats ◽  
Serum Blood Urea Nitrogen ◽  
Dose Dependent

Pretreatment of Swiss mice and Sprague-Dawley rats with glutathione (GSH) reduced the acute lethal toxicity of cis-dichlorodiammine platinum (II) (cis-DDP) in a dose-dependent manner. The protection was accompanied by reduction of both body weight loss and by reduction of nephrotoxicity, as measured by a rise in serum blood urea nitrogen (BUN), creatinine levels and by histopathologic changes, which occurred 4 days following cis-DDP treatment. The antitumor effects of cis-DDP on experimental tumor models (P388 and Gross leukemia) were not significantly altered by GSH treatment. It is suggested that the partial protection by GSH from acute toxicity of the antitumor drug is directly related to protection of renal function.

scholarly journals Expression of phospholemman and its association with Na+-K+-ATPase in skeletal muscle: effects of aging and exercise training

2005 ◽  
Vol 99 (4) ◽  
pp. 1508-1515 ◽  
Author(s):  
Justin Reis ◽  
Lianqin Zhang ◽  
Steve Cala ◽  
Korinne N. Jew ◽  
Lisa C. Mace ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Treadmill Exercise ◽  
Accessory Protein ◽  
Dependent Manner ◽  
Muscle Type ◽  
Effects Of Aging ◽  
High Level ◽  
Reduced Activity ◽  
Α Subunits

Phospholemman (PLM) is a recently identified accessory protein of the Na+-K+-ATPase (NKA), with a high level of expression in skeletal muscle. The objectives of this study are to characterize the PLM in skeletal muscle and to test the hypothesis that, as an accessory protein of NKA, expression of PLM and its association with the α-subunits of NKA is regulated during aging and with exercise training. PLM was characterized in skeletal muscle of 6- and 16-mo-old sedentary middle-aged rats (Ms), and the effects of aging and exercise training were studied in Ms, 29-mo-old sedentary senescent, and 29-mo-old treadmill-exercised senescent rats. Expression of PLM was muscle-type dependent, and immunofluorescence study showed that PLM distributed predominantly on the sarcolemmal membrane of the muscle fibers. Anti-PLM antibody reduced activity of NKA, and thus PLM appears to be required for NKA to express its full activity in skeletal muscle. Expression of PLM was not altered with aging but increased after exercise training. Coimmunoprecipitation studies demonstrated that PLM associates with both the α1- and α2-subunit isoforms of NKA. Compared with Ms rats, levels of PLM-associated α1-subunit increased in 29-mo-old sedentary senescent rats, and treadmill exercise has a tendency to partially reverse it. There was no significant change in PLM-associated α2-subunit with age, and exercise training has a tendency to increase that level. It is concluded that, in skeletal muscle, PLM appears to be a protein integral to the NKA complex and that PLM has the potential to modulate NKA in an isoform-specific and muscle type-dependent manner in aging and after exercise training.

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