Different Doxorubicin Formulations Affect Plasma 4-Hydroxy-2-Nonenal and Gene Expression of Aldehyde Dehydrogenase 3A1 and Thioredoxin Reductase 2 in Rat

Fatty Acid Supplementation Affects Skin Wound Healing in a Rat Model

Polyunsaturated fatty acids (PUFA) play an important role in reparative processes. The ratio of PUFAs n-3 to n-6 may affect wound healing. The study aimed to evaluate the effect of dietary supplementation with n-3 and n-6 PUFA in two proportions on skin wounds in laboratory rats. Adult male Wistar rats received 20% fat emulsion with a ratio of 1.4:1 (group A) or 4.3:1 (group B) for n-3:n-6 PUFAs at a daily dose of 1 mL/kg. The control group received water under the same conditions. The animals were supplemented a week before and a week after the skin excision performed on the back. The level of wound closure, various parameters of oxidative stress, and plasma fatty acids composition were evaluated. Wound tissue samples were examined by electron microscopy. The administration of fat emulsions led to significant changes in plasma polyunsaturated fatty acid composition. The increased production of reactive nitrogen species, as well as more numerous newly formed blood vessels and a greater amount of highly organized collagen fibrils in both groups A and B may indicate more intensive healing of the skin wound in rats supplemented with polyunsaturated fatty acids in high n-3:n-6 ratio.

Effect of doxorubicin on cardiac lipid metabolism-related transcriptome and the protective activity of Alda-1

The use of doxorubicin (DOX) as an antineoplastic drug is compromised by its cardiotoxicity risk. Although several mechanisms have been proposed for DOX-induced cardiac dysfunction, there is still increased interest in assessing its effects. Likewise, it is important to find protocols that can prevent or minimize the side effects of DOX without hindering its antitumor activity. Thus, this study was designed to investigate the molecular mechanisms underlying DOX cardiotoxicity, with a special focus on cardiac energy metabolism and the ability of Alda-1 (ALDH2 agonist) to prevent DOX-induced cardiac alterations. We explored the effects of DOX on the histological morphology of the myocardium, on lipid profile, and on the expression of genes related to fatty acid metabolism, in the presence and absence of Alda-1 (8 mg/kg body weight; b.wt.). Two DOX treatment protocols were used: a single dose of DOX (4 mg/kg b.wt.); four doses of DOX (4 mg/kg b.wt.), one dose/week, for 4 weeks. Treatment with DOX caused a progressive injury in the cardiac tissue and an increase in the blood total cholesterol, high-density lipoproteins, very low-density lipoproteins and triglyceride, as well as an up-regulation of FABP4 (DOX and DOX + Alda-1 groups) and Slc27a2 (in DOX-treated animals). Alda-1 administration promoted reduction in the severity of the histopathological injuries (after single dose of DOX) and Slc27a2 overexpression was restored. In conclusion, the study revealed novel insights regarding the development of DOX-mediated cardiomyopathy, indicating a relationship between DOX exposure and FABP4 and Slc27a2 overexpression, and confirmed the cardioprotective effect of Alda-1.

iTRAQ-Based Proteomic Profiling of Potential Biomarkers in Rat Serum for Uranium Tailing Suspension Intratracheal Instillation

Protection against low-dose ionizing radiation is of great significance. Uranium tailings are formed as a byproduct of uranium mining and a potential risk to organisms. In this study, we identified potential biomarkers associated with exposure to low-dose radiation from uranium tailings. We established a Wistar rat model of low dose rate irradiation by intratracheal instillation of a uranium tailing suspension. We observed pathological changes in the liver, lung, and kidney tissues of the rats. Using isobaric tags for relative and absolute quantification, we screened 17 common differentially expressed proteins in three dose groups. We chose alpha-1 antiproteinase (Serpina1), keratin 17 (Krt17), and aldehyde dehydrogenase (Aldh3a1) for further investigation. Our data showed that expression of Serpina1, Krt17, and Aldh3a1 had changed after the intratracheal instillation in rats, which may be potential biomarkers for uranium tailing low-dose irradiation. However, the underlying mechanisms require further investigation.

Tangeretin-Assisted Platinum Nanoparticles Enhance the Apoptotic Properties of Doxorubicin: Combination Therapy for Osteosarcoma Treatment

Osteosarcoma (OS) is the most common type of cancer and the most frequent malignant bone tumor in childhood and adolescence. Nanomedicine has become an indispensable field in biomedical and clinical research, with nanoparticles (NPs) promising to increase the therapeutic efficacy of anticancer drugs. Doxorubicin (DOX) is a commonly used chemotherapeutic drug against OS; however, it causes severe side effects that restrict its clinical applications. Here, we investigated whether combining platinum NPs (PtNPs) and DOX could increase their anticancer activity in human bone OS epithelial cells (U2OS). PtNPs with nontoxic, effective, thermally stable, and thermoplasmonic properties were synthesized and characterized using tangeretin. We examined the combined effects of PtNPs and DOX on cell viability, proliferation, and morphology, reactive oxygen species (ROS) generation, lipid peroxidation, nitric oxide, protein carbonyl content, antioxidants, mitochondrial membrane potential (MMP), adenosine tri phosphate (ATP) level, apoptotic and antiapoptotic gene expression, oxidative stress-induced DNA damage, and DNA repair genes. PtNPs and DOX significantly inhibited U2OS viability and proliferation in a dose-dependent manner, increasing lactate dehydrogenase leakage, ROS generation, and malondialdehyde, nitric oxide, and carbonylated protein levels. Mitochondrial dysfunction was confirmed by reduced MMP, decreased ATP levels, and upregulated apoptotic/downregulated antiapoptotic gene expression. Oxidative stress was a major cause of cytotoxicity and genotoxicity, confirmed by decreased levels of various antioxidants. Furthermore, PtNPs and DOX increased 8-oxo-dG and 8-oxo-G levels and induced DNA damage and repair gene expression. Combination of cisplatin and DOX potentially induce apoptosis comparable to PtNPs and DOX. To the best of our knowledge, this is the first report to describe the combined effects of PtNPs and DOX in OS.

Heavy metal hypertolerant eukaryotic aldehyde dehydrogenase isolated from metal contaminated soil by metatranscriptomics approach

Constant addition of heavy metal pollutants in soil resulting from anthropogenic activities can prove detrimental to both macro and micro life forms inhabiting the ecosystem. The potential functional roles of eukaryotic microbes in such environment were explored in this study by metatranscriptomics approach. Sized eukaryotic cDNA libraries, library A (<0.5 kb), library B (0.5-1.0 kb), and library C (>1 kb) were constructed from the soil RNA and screened for copper (Cu) tolerance genes by using copper sensitive yeast mutant strain cup1^Δ. Screening of the cDNA libraries yielded different clones capable of growing in Cu amended medium. In the present investigation, one of the transcripts PLCc38 from the library C was characterized and tested for its ability to tolerate different heavy metals by using metal sensitive yeast mutants. Sequence analysis PLCc38 showed homology with aldehyde dehydrogenase (ALDH) and capable of tolerating high concentrations of Cu (150-1000 μM). Aldeyde dehydrogenases are stress response enzymes capable of eliminating toxic levels of aldehydes generated due to abiotic environmental stresses. The cDNA PLCc38 also provided tolerance to wide range of Cd (40-100 μM), Zn (10-13 mM) and Co (2-50 mM) concentrations. Oxidative stress tolerance potential of PLCc38 was also confirmed in presence of different concentrations of H₂O₂. This study proves that PLCc38 is a potent gene associated with metal tolerance which could be used to revegetate heavy metal polluted soil or as a biomarker for detection of metal contamination.

Haloperidol affects coupling between QT and RR intervals in guinea pig isolated heart

Prolonged QT interval is an independent risk factor for development of ventricular arrhythmias. Haloperidol is one of the drugs inducing QT prolongation. Previous studies showed that haloperidol affects not only QT duration but also heart rate (RR interval). The present work focused on relationship between QT and RR and its changes under acute and chronic haloperidol administration. The study included 14 male guinea pigs divided into control and haloperidol-treated group. After 21-days administration of haloperidol or vehiculum, electrograms in isolated hearts were recorded. QT/RR and dQT/dRR coupling were calculated. Chronic haloperidol administration significantly decreases the coupling between QT and RR. Acute haloperidol exposure significantly decreases the dQT/dRR coupling in both treated and untreated guinea pig hearts. Flatter QT/RR relationship reveals a lack of QT adaptation to increased heart rate. It should be emphasized that in such situation ECG recording will not show significant QT prolongation evaluated according to clinical rules. However, if QT interval does not adapt to increased heart rate sufficiently, the risk of ventricular arrhythmias may be increased despite practically normal QT interval length. The results are supported by findings in biochemical analyses, which proved eligibility of the used model.

l-Glutamine Attenuates Apoptosis in Porcine Enterocytes by Regulating Glutathione-Related Redox Homeostasis

Background

Programmed cell death plays a fundamental role in intestinal development and mucosal homeostasis. Dysregulation of these processes is associated with an impaired intestinal-mucosal barrier, reduced nutrient absorption, and initiation and progression of intestinal diseases. 4-Hydroxy-2-nonenal (4-HNE), a product of lipid peroxidation, is commonly used to induce oxidative stress in cells. l-Glutamine is known to protect cells from apoptosis. However, the underlying mechanisms are largely unknown.

Objective

This study was conducted to test the hypothesis that l-glutamine attenuates 4-HNE-induced apoptosis by modulating glutathione (GSH) and thioredoxin (TXN) antioxidant systems and the expression of genes involved in 4-HNE metabolism in enterocytes.

Methods

Intestinal porcine epithelial cell line 1 (IPEC-1) cells were cultured with or without 4-HNE (30 μmol/L) in the presence of 0.05 or 0.25 mmol l-glutamine/L (a physiological concentration in the lumen of the small intestine) for indicated time periods. Cell viability, abundances of apoptotic proteins, mitochondrial membrane depolarization, production of reactive oxygen species (ROS) and GSH, and expression of genes involved in the biosynthesis of GSH, thioredoxin, and 4-HNE metabolism were determined.

Results

Compared with basal medium containing 0.05 mmol l-glutamine/L, 4-HNE enhanced apoptosis by 19.6% (P < 0.05) in a caspase-3-dependent manner. This effect was accompanied by elevated intracellular ROS production (39.5% and 85.3% for 2- and 4-h treatment, respectively), increased mitochondrial depolarization by 80%, and decreased intracellular GSH concentrations by 17.7%. These effects of 4-HNE were reduced by 0.25 mmol l-glutamine/L. Further study showed that the protective effect of l-glutamine was associated with the enhanced expression of genes involved in GSH production (including GCLC, GCLM, GSR, CBS, and CTH) by 3.9-14-fold, as well as genes involved in 4-HNE metabolism [e.g., glutathione S-transferase A (GSTA)1 and GSTA4] by 1.9-7.2-fold. The mRNA levels for ADH5, AKR1C1, AKR1A1, and TXNRD1 were enhanced 1.4-8.8-fold by 4-HNE but were not changed in cells co-treated with 4-HNE and l-glutamine.

Conclusion

These findings indicate that l-glutamine attenuates 4-HNE-induced apoptosis by regulating GSH-related redox homeostasis and enhancing GSTA-mediated metabolism in enterocytes.

Enzymatic and non-enzymatic detoxification of 4-hydroxynonenal: Methodological aspects and biological consequences

4-Hydroxynonenal (HNE), an electrophilic end-product deriving from lipid peroxidation, undergoes a heterogeneous set of biotransformations including enzymatic and non-enzymatic reactions. The former mostly involve red-ox reactions on the HNE oxygenated functions (phase I metabolism) and GSH conjugations (phase II) while the latter are due to the HNE capacity to spontaneously condense with nucleophilic sites within endogenous molecules such as proteins, nucleic acids and phospholipids. The overall metabolic fate of HNE has recently attracted great interest not only because it clearly determines the HNE disposal, but especially because the generated metabolites and adducts are not inactive molecules (as initially believed) but show biological activities even more pronounced than those of the parent compound as exemplified by potent pro-inflammatory stimulus induced by GSH conjugates. Similarly, several studies revealed that the non-enzymatic reactions, initially considered as damaging processes randomly involving all endogenous nucleophilic reactants, are in fact quite selective in terms of both reactivity of the nucleophilic sites and stability of the generated adducts. Even though many formed adducts retain the expected toxic consequences, some adducts exhibit well-defined beneficial roles as documented by the protective effects of sublethal concentrations of HNE against toxic concentrations of HNE. Clearly, future investigations are required to gain a more detailed understanding of the metabolic fate of HNE as well as to identify novel targets involved in the biological activity of the HNE metabolites. These studies are and will be permitted by the continuous progress in the analytical methods for the identification and quantitation of novel HNE metabolites as well as for proteomic analyses able to offer a comprehensive picture of the HNE-induced adducted targets. On these grounds, the present review will focus on the major enzymatic and non-enzymatic HNE biotransformations discussing both the molecular mechanisms involved and the biological effects elicited. The review will also describe the most important analytical enhancements that have permitted the here discussed advancements in our understanding of the HNE metabolic fate and which will permit in a near future an even better knowledge of this enigmatic molecule.

Tolerance of isolated rabbit hearts to short ischemic periods is affected by increased LV mass fraction

Hypertrophied hearts are known for increased risk of arrhythmias and are linked with reduced ischemic tolerance. However, still little is known about state characterized only by increased left ventricle (LV) mass fraction. Seventeen isolated rabbit hearts with various LV mass were divided into two groups according to LV weight/heart weight ratio (LVW/HW ratio), namely group H and L (with higher and lower LVW/HW ratio, respectively) and underwent three short cycles of global ischemia and reperfusion. The differences in electrogram (heart rate, QRS(max), mean number, onset and dominant form of ventricular premature beats) and in biochemical markers of myocardial injury (creatine kinase, lactate dehydrogenase - LDH) and lipid peroxidation (4-hydroxy-2-nonenal - 4-HNE) were studied. As compared to group L, hearts in group H exhibited lower tolerance to ischemia expressed as higher incidence and severity of arrhythmias in the first ischemic period as well as increase of LDH and 4-HNE after the first reperfusion. In the third cycle of ischemia-reperfusion, the preconditioning effect was observed in both electrophysiological parameters and LDH release in group H. Our results showed consistent trends when comparing changes in electrograms and biochemical markers. Moreover, 4-HNE seems to be good potential parameter of moderate membrane alteration following ischemia-reperfusion injury.