Tyrosine can protect against oxidative stress through ferryl hemoglobin reduction

The anti-cholestatic effects of Coptis chinensis Franch. alone and combined with Tetradium ruticarpum (A. Jussieu) T. G. Hartley: dual effects on fecal metabolism and microbial diversity

Introduction: Drug dosages and combinations are the main factors that affect the efficacy of pleiotropic traditional Chinese medicine (TCM). Coptis chinensis Franch. (CF) is a representative TCM with multiple effects and is often combined with Tetradium ruticarpum (A. Jussieu) T. G. Hartley (TR) to treat cholestasis. The present study assessed the influence of CF dose and its combination with TR on the efficacy of CF in cholestasis treatment, including their effects on fecal metabolism and fecal microorganisms. Methods: Rats with α-naphthylisothiocyanate (ANIT, 50 mg/kg)-induced cholestasis were administered low (0.3 g/kg) and high (0.6 g/kg) doses of CF, as well as CF combined with TR at doses of 0.6 g/kg and 0.9 g/kg, respectively. The anti-cholestatic effects of these treatments were assessed by determining their anti-inflammatory, hypolipidemic, and anti-oxidative stress properties. Additionally, fecal metabolomics and fecal microorganisms were analyzed. Results: Low dose CF had a more potent hypolipidemic effect than high dose CF, whereas high dose CF had more potent anti-inflammatory and anti-oxidative stress effects. Combination with TR enhanced the hypolipidemic effect, but antagonized the anti-inflammatory effect, of CF. Analyses of fecal metabolomics and fecal microorganisms showed differences in the regulation of lipid- and amino acid metabolism-related pathways, including pathways of linoleic acid, tyrosine, and arachidonic acid metabolism, and amino acid biosynthesis between different doses of CF as well as between different doses of CF in combination with TR. These differences may contribute to differences in the anti-cholestatic effects of these preparations. Conclusion: CF dose influences its anti-cholestatic efficacy. The combination with TR had synergistic or antagonistic effects on the properties of CF, perhaps by altering fecal metabolism and fecal microbial homeostasis.

Effects of different colors of plastic-film mulching on soil temperature, yield, and metabolites in Platostoma palustre

Platostoma palustre is an annual herb and an important medicinal and edible plant in southern China. Plastic-film mulching is an effective agronomic practice in the cultivation system of P. palustre, of which black-film mulching is the most common. However, fewer researches have been focused on the use of other colors of plastic films in P. palustre cultivation. In this study, different colors (white, black, red, and green) of plastic film were adopted, and the effects of different colors of plastic film mulching on the soil temperature, yield, and metabolites of P. palustre were investigated. The results showed that the fresh weight of a single plant of the green film treatment was significantly higher than that of the white film treatment (n = top 28). Based on the results of three temperature measurements, the soil temperature was almost the highest in the red film treatment and lowest in the white film treatment. The metabolomic analysis revealed that a total of 103 differential metabolites were identified. Among these, the gluconic acid, deoxyribose, and N-Acetylmannosamine in the red film treatment presented the highest abundance compared with the other treatments, meanwhile, the abundances of the five monosaccharides in the red film treatment were significantly higher than those of the green film treatment. Moreover, the sucrose, trehalose, and D-(+)-trehalose in the green film treatment exhibited the highest abundance, and the abundances of eight different amino acids in the red film treatment were almost the lowest while those in the black film treatment were almost the highest. Further analysis of the membership function values indicated that the black and red film treatments might be more suitable for the cultivation and quality production of P. palustre in comparison with the other two treatments. This study will provide a theoretical basis for improving the efficient cultivation technology of P. palustre and forming a theoretical system of P. palustre film mulching cultivation.

Potential Antioxidative Activity of Homocysteine in Erythrocytes under Oxidative Stress

Homocysteine is an amino acid containing a free sulfhydryl group, making it probably contribute to the antioxidative capacity in the body. We recently found that plasma total homocysteine (total-Hcy) concentration increased with time when whole blood samples were kept at room temperature. The present study was to elucidate how increased plasma total-Hcy is produced and explore the potential physiological role of homocysteine. Erythrocytes and leukocytes were separated and incubated in vitro; the amount of total-Hcy released by these two kinds of cells was then determined by HPLC-MS. The effects of homocysteine and methionine on reactive oxygen species (ROS) production, osmotic fragility, and methemoglobin formation in erythrocytes under oxidative stress were studied. The reducing activities of homocysteine and methionine were tested by ferryl hemoglobin (Hb) decay assay. As a result, it was discovered that erythrocytes metabolized methionine to homocysteine, which was then oxidized within the cells and released to the plasma. Homocysteine and its precursor methionine could significantly decrease Rosup-induced ROS production in erythrocytes and inhibit Rosup-induced erythrocyte's osmotic fragility increase and methemoglobin formation. Homocysteine (but not methionine) was demonstrated to enhance ferryl Hb reduction. In conclusion, erythrocytes metabolize methionine to homocysteine, which contributes to the antioxidative capability under oxidative stress and might be a supplementary protective factor for erythrocytes against ROS damage.

Serum Metabolomics of Benign Essential Blepharospasm Using Liquid Chromatography and Orbitrap Mass Spectrometry

Background

Benign essential blepharospasm (BEB) is a form of focal dystonia that causes excessive involuntary spasms of the eyelids. Currently, the pathogenesis of BEB remains unclear. This study is aimed at investigating the serum metabolites profiles in patients with BEB and healthy control and to identify the mechanism and biomarkers of this disease.

Methods

30 patients with BEB and 33 healthy controls were recruited for this study. We conducted the quantitative and nontargeted metabolomics analysis of the serum samples from 63 subjects by using liquid chromatography and Orbitrap mass spectrometry (LC-Orbitrap MS). Multivariate statistical analysis was performed to detect and identify different metabolites between the two groups. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and receiver operating characteristic (ROC) curve analysis of the altered metabolites were performed.

Results

A total of 134 metabolites were found and identified. The metabolites belonged to several metabolic pathways including phenylalanine metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, arginine biosynthesis, linoleic acid metabolism, tryptophan metabolism, aminoacyl-tRNA biosynthesis, sphingolipid metabolism, glycosphingolipid biosynthesis, leucine and isoleucine biosynthesis, and vitamin B6 metabolism. Eight metabolites were identified as the potential biomarkers.

Conclusions

These results demonstrated that serum metabolic profiling of BEB patients was significantly different from healthy controls based on LC-Orbitrap MS. Besides, metabolomics might provide useful information for a better understanding of BEB.

In vitro digestion of a mixed gel of pork muscle and resistant starch: Salt-soluble protein perspective

The in vitro digestion of a mixed gel (MS) of pork muscle and resistant starch (RS) was investigated and the role of the salt-soluble protein (SSP) in the function promotion of the mixed gel was clarified. The results showed that the mixed muscle gel (MS) and the addition of RS to muscle gel (M + S) presented an improved protein digestion, as indicated by a reduced particle size of the hydrolysates, more degradation of proteins with large molecular weight and more generation of free amino acids compared with the RS-free muscle gel (M). Meanwhile, the hydrolysates of the M + S and MS showed intensified DPPH radical scavenging activities. Specifically, the MS exerted preferable properties in protein digestion and antioxidant activity. Similar digestion characteristics were noticed in mixed SSP gels.The current study revealed that the reinforced functionality of the mixed muscle gel was associated with the binding relationships between SSP and RS during cooking.

A comparative study between curcumin and curcumin nanoemulsion on high-fat, high-fructose diet-induced impaired spermatogenesis in rats

Objectives

Curcumin is a promising nutraceutical with reported diverse therapeutic properties, but of limited oral bioavailability. The current manuscript investigates the role of encapsulation of curcumin in nanoemulsion form in counteracting the adverse effect of chronic ingestion of a high-fat high-fructose diet (HFHF) by juvenile male rats regarding testicular abnormalities and declined spermatogenesis.

Methods

Curcumin nanoemulsion was administered orally to Wistar rats at a dose of 5 or 10 mg/kg and compared with curcumin powder, followed by a pharmacological and histological assessment.

Key findings

Results demonstrated that curcumin nanoemulsion was superior to curcumin powder, particularly in enhancing the percentage progressive motility of spermatozoa, normalization of essential and non-essential amino acids in semen, normalization of serum leptin and testosterone levels, as well as normalization of oxidative and nitrosative parameters. It was also proven to reduce testicular DNA fragmentation, while elevating testicular cellular energy. In addition, curcumin nanoemulsion administered at a dose of 10 mg/kg induced the highest level of spermatogenesis, delineated by histological examination of the seminiferous tubules.

Conclusions

It can be concluded that curcumin nanoemulsion administered at a dose of 10 mg/kg successfully ameliorates the adverse effects of a HFHF on spermatogenesis.

Serum Metabolomic Profiling Based on Fourier Transform-Ion Cyclotron Resonance-Mass Spectrometry: Do the Dysfunctions of Metabolic Pathways Reveal a Universal Risk of Oxidative Stress in Schizophrenia?

Schizophrenia is a chronic, disabling, and complex mental illness, of which the pathogenesis remains elusive. To provide clues for the pathogenesis and etiology of schizophrenia, we performed serum metabolic profiling in 54 patients with schizophrenia and 54 matched healthy controls using Fourier transform-ion cyclotron resonance-mass spectrometry. Based on 94 differential metabolites identified, we discovered two dysregulated metabolic pathways in schizophrenia, including the upregulated arachidonic acid-related pathway and the downregulated aromatic amino acid-related pathway. Moreover, carnitine was identified as a promising diagnostic biomarker for schizophrenia with an area under the curve of 0.997. Given the antioxidant and pro-oxidant properties of these altered metabolites, these results pointed to an imbalance of the redox homeostasis in schizophrenia, which was further confirmed by a remarkable elevation of 8-hydroxydeoxyguanosine (8-OHdG), a reactive oxidative stress marker. Furthermore, correlation analyses demonstrated that 8-OHdG was negatively correlated with antioxidant biliverdin and positively related to oxidation products, 9-hydroxylinoleic acid and o-tyrosine, and that total antioxidant capacity was positively associated with antioxidant acetylcarnitine in schizophrenia. Our results lead to the hypothesis that the disturbed metabolic characteristics reveal enhanced oxidative stress, which in turn results in the damage of lipids, proteins, and DNA and ultimately promotes the development of schizophrenia.

Functional potato bioactive peptide intensifies Nrf2-dependent antioxidant defense against renal damage in hypertensive rats

Hypertension, which is known as a silent killer, is the second leading cause of kidney failure worldwide. Elevated blood pressure causes approximately 7.6 million deaths, which account for ~13.5% of the total deaths and will continue to rise. High blood pressure is the prime risk factor associated with complications in major organs, including the heart, brain and kidney. High blood pressure accelerates oxidative stress and thereby causes organ dysfunction through the production of reactive oxygen species. In this study, we investigated the renal-protective effects of the bioactive peptide IF from alcalase potato protein hydrolysate in spontaneously hypertensive rat kidney. Sixteen-week-old spontaneously hypertensive rats were divided into three groups (n = 6), and Sixteen-week-old Wistar Kyoto rats (n = 6) served as the control group. The rats were administered IF and captopril via oral gavage for 8 weeks and then sacrificed, and their kidneys were harvested. The kidney sections from the rats treated with IF showed restoration of the structure of the glomerulus and Bowman's capsule. The expression levels of Nrf2-mediated antioxidants were also increased, as confirmed by 4-hydroxynonenal immunohistochemical staining. The TUNEL assay revealed a significant reduction in the number of apoptotic cells in the IF-treated groups, which was consistent with the western blot results. Thus, the bioactive peptide IF exerts potential protective effects against hypertension-associated ROS-mediated renal damage via the Nrf2-dependent antioxidant pathway along the DJ-1 and AKT axes. Hence, we speculate that IF might have promising therapeutic effects on renal damage associated with hypertension.

Oxygen Self-Production Red Blood Cell Carrier System for MRI Mediated Cancer Therapy: Ferryl-Hb, Sonodynamic, and Chemical Therapy

Hypoxia in tumors can lead to insufficient oxygen supply during sonodynamic therapy (SDT), which in turn strengthens tumor resistance to sonodynamic efficacy. To conquer hypoxia in tumors and improve the treatment effectiveness, we developed oxygen self-production red blood cell (RBC) carrier system to decompose tumor endogenic H₂O₂ into O₂ and combine triplex cancer therapy: ferryl-hemoglobin (ferryl-Hb), sonodynamic, and chemical therapy. Both hydrophilic sonosensitizer and doxorubicin (DOX) were encapsulated inside RBCs (DOX/Mn-TPPS@RBCs). The drug release can be improved by combining the effects of H₂O₂ and ultrasonic irradiation. Here, we introduced a contrast agent, meso-tetra (4-sulfonatephenyl) porphyrinate manganese(III) complex (Mn-TPPS), which could be used to enhance the signal intensity of magnetic resonance imaging (MRI) of the tumor site. The feasibility of Mn-TPPS as a sonosensitizer was investigated during SDT. Importantly, DOX/Mn-TPPS@RBCs overcame hypoxia in the tumor and improved the efficacy of SDT owing to the O₂ generation by the catalase-catalyzed decomposition of tumor endogenic H₂O₂. Hemoglobin was simultaneously oxidized into highly oxidative ferryl-Hb species by H₂O₂ and reactive oxygen species, resulting in cytotoxicity. Overall, this drug delivery system is a promising therapeutic agent involving in situ production of oxygen inside the tumor, triplex therapy, and MRI.

Peroxidase Activity of Human Hemoproteins: Keeping the Fire under Control

The heme in the active center of peroxidases reacts with hydrogen peroxide to form highly reactive intermediates, which then oxidize simple substances called peroxidase substrates. Human peroxidases can be divided into two groups: (1) True peroxidases are enzymes whose main function is to generate free radicals in the peroxidase cycle and (pseudo)hypohalous acids in the halogenation cycle. The major true peroxidases are myeloperoxidase, eosinophil peroxidase and lactoperoxidase. (2) Pseudo-peroxidases perform various important functions in the body, but under the influence of external conditions they can display peroxidase-like activity. As oxidative intermediates, these peroxidases produce not only active heme compounds, but also protein-based tyrosyl radicals. Hemoglobin, myoglobin, cytochrome c/cardiolipin complexes and cytoglobin are considered as pseudo-peroxidases. Рeroxidases play an important role in innate immunity and in a number of physiologically important processes like apoptosis and cell signaling. Unfavorable excessive peroxidase activity is implicated in oxidative damage of cells and tissues, thereby initiating the variety of human diseases. Hence, regulation of peroxidase activity is of considerable importance. Since peroxidases differ in structure, properties and location, the mechanisms controlling peroxidase activity and the biological effects of peroxidase products are specific for each hemoprotein. This review summarizes the knowledge about the properties, activities, regulations and biological effects of true and pseudo-peroxidases in order to better understand the mechanisms underlying beneficial and adverse effects of this class of enzymes.

Self-Monitoring Artificial Red Cells with Sufficient Oxygen Supply for Enhanced Photodynamic Therapy

Photodynamic therapy has been increasingly applied in clinical cancer treatments. However, native hypoxic tumoural microenvironment and lacking oxygen supply are the major barriers hindering photodynamic reactions. To solve this problem, we have developed biomimetic artificial red cells by loading complexes of oxygen-carrier (hemoglobin) and photosensitizer (indocyanine green) for boosted photodynamic strategy. Such nanosystem provides a coupling structure with stable self-oxygen supply and acting as an ideal fluorescent/photoacoustic imaging probe, dynamically monitoring the nanoparticle biodistribution and the treatment of PDT. Upon exposure to near-infrared laser, the remote-triggered photosensitizer generates massive cytotoxic reactive oxygen species (ROS) with sufficient oxygen supply. Importantly, hemoglobin is simultaneously oxidized into the more active and resident ferryl-hemoglobin leading to persistent cytotoxicity. ROS and ferryl-hemoglobin synergistically trigger the oxidative damage of xenograft tumour resulting in complete suppression. The artificial red cells with self-monitoring and boosted photodynamic efficacy could serve as a versatile theranostic platform.