p53 inhibitor or antioxidants reduce the severity of ethmoid plate deformities in zebrafish Type 3 Treacher Collins syndrome model

Treacher Collins syndrome-3 (TCS-3) is a rare congenital craniofacial disorder attributed to variants in the RNA pol I subunit C (POLR1C). The pathogenesis of TCS-3 linked to polr1c involves the activation of apoptosis-dependent p53 pathways within neural crest cells (NCCs). This occurs due to disruptions in ribosome biogenesis, and the restoration of polr1c expression in early embryogenesis effectively rescues the observed craniofacial phenotype in polr1c-deficient zebrafish. Clinical variability in TCS patients suggests interactions between genes and factors like oxidative stress. Elevated production of reactive oxygen species (ROS) in epithelial cells may worsen phenotypic outcomes in TCS individuals. Our study confirmed excessive ROS production in facial regions, inducing apoptosis and altering p53 pathways. Deregulated cell-cycle and epithelial-to-mesenchymal transition (EMT) genes were also detected in the TCS-3 model. Utilizing p53 inhibitor (Pifithrin-α; PFT-α) or antioxidants (Glutathione; GSH and N-Acetyl-L-cysteine; NAC) effectively corrected migrated NCC distribution in the pharyngeal arch (PA), suppressed oxidative stress, prevented cell death, and modulated EMT inducers. Crucially, inhibiting p53 activation or applying antioxidants within a specific time window, notably within 30 h post-fertilization (hpf), successfully reversed phenotypic effects induced by polr1c MO.

Fate characteristics and risk quantification of cyflumetofen from tomato cultivation to processing based on large-scale applications

Elucidating the fate characteristics of cyflumetofen and its main metabolite 2-TFMBA in tomato from cultivation to processing is crucial for safeguarding the environment and humans from hazardous effects. Cyflumetofen and 2-TFMBA could exist stably in tomato matrices for at least 343 days under frozen and dark conditions according to UHPLC-MS/MS, with a limit of quantitation of 0.001 mg/kg and retention time within 2.12 min. The occurrence, dissipation, and concentration variation of cyflumetofen were reflected by original depositions of 0.02-0.44 mg/kg, half-lives of 1.7-7.2 days, and terminal magnitudes of 0.005-0.30 mg/kg, respectively, with various influencing factors, e.g., climate conditions and tomato cultivars. Additionally, 13.5-59.3% of cyflumetofen was metabolized to 2-TFMBA, showing significant toxicological effects ranging from cultivation to processing. When the concentration decreased by 0.06 mg/kg, cyflumetofen was effectively removed by peeling, while washing was the recommended method for removing 2-TFMBA with a processing factor of 0.70. The comparative dietary risks of sum cyflumetofen were assessed for all life cycle populations using deterministic and probabilistic models. The risk quotients decreased to 1.3-4.8 times during the preparation of home canning tomato paste. Despite the low exposure risk, the potential health hazards of sum cyflumetofen should be considered, given its ubiquity and cumulative effects.

Selenium deficiency exacerbated Bisphenol A-induced intestinal toxicity in chickens: Apoptosis and cell cycle arrest mediated by ROS/P53

Bisphenol A (BPA) is a phenolic organic synthetic compound that is used as the raw material of polycarbonate plastics, and its safety issues have recently attracted wide attention. Selenium (Se) deficiency has gradually developed into a global disease affecting intestinal function via oxidative stress and apoptosis. However, the toxic effects and potential mechanisms of BPA exposure and Se deficiency in the chicken intestines have not been studied. In this study, BPA exposure and/or Se deficiency models were established in vivo and in vitro to investigate the effects of Se deficiency and BPA on chicken jejunum. The results showed that BPA exposure and/or Se deficiency increased jejunum oxidative stress and DNA damage, activated P53 pathway, led to mitochondrial dysfunction, and induced apoptosis and cell cycle arrest. Using protein-protein molecular docking, we found a strong binding ability between P53 and peroxisome proliferator-activated receptor γ coactivator-1, thereby regulating mitochondrial dysfunctional apoptosis. In addition, we used N-acetyl-L-cysteine and pifithrin-α for in vitro intervention and found that N-acetyl-L-cysteine and pifithrin-α intervention reversed the aforementioned adverse effects. This study clarified the potential mechanism by which Se deficiency exacerbates BPA induced intestinal injury in chickens through reactive oxygen species/P53, which provides a new idea for the study of environmental combined toxicity of Se deficiency, and insights into animal intestinal health from a new perspective.

Protocol for preparing dynamic covalent macrocycles for co-delivering genes and drugs to cancer cell lines

Combination therapy using effective drug molecules and functional genes such as small interfering RNA (siRNA) has been suggested as a powerful strategy against multiple drug resistance. Here, we present a protocol for preparing a delivery system by developing dynamic covalent macrocycles using a dithiol monomer to co-deliver doxorubicin and siRNA. We describe steps for preparing the dithiol monomer, followed by co-delivery to form nanoparticles. We then detail procedures for cell uptake and assessing enhanced anti-cancer efficacy in vitro. For complete details on the use and execution of this protocol, please refer to Lyu et al.1.

Preserving DNA in Biodegradable Organosilica Encapsulates

A core-shell strategy was developed to protect synthetic DNA in organosilica particles encompassing dithiol linkages allowing for a DNA loading of 1.1 wt %. DNA stability tests involving bleach as an oxidant showed that following the procedure DNA was sandwiched between core particles of ca. 450 nm size and a protective outer layer, separating the DNA from the environment. Rapid aging tests at 60 °C and 50% relative humidity revealed that the DNA protected within this material was significantly more stable than nonprotected DNA, with an expected ambient temperature half-life of over 60 years. Still, and due to the presence of the dithiol linkages in the backbone of the organosilica material, the particles degraded in the presence of reducing agents (TCEP and glutathione) and disintegrated within several days in a simulated compost environment, which was employed to test the biodegradability of the material. This is in contrast to DNA encapsulated following state of the art procedures in pure SiO₂ particles, which do not biodegrade in the investigated timeframes and conditions. The results show that synthetic DNA protected within dithiol comprising organosilica particles presents a strategy to store digital data at a high storage capacity for long time frames in a fully biodegradable format.

Urea transporter B downregulates polyamines levels in melanoma B16 cells via p53 activation

Urea transporter B (UT-B, encoded by the SLC14A1 gene) is a membrane channel protein involved in urea transmembrane transport. Compared with normal tissues, UT-B expression is significantly decreased in most tumours, especially melanoma. However, the UT-B role in tumorigenesis and development is still unclear. Herein, we investigated the effects of UT-B overexpression on polyamine metabolism and the urea cycle in murine melanoma B16 cells, to explore the roles of mitochondrial dysfunction and p53 activation in cell growth and polyamines metabolism. UT-B overexpression in B16 cells decreased cell growth, increased apoptosis, and significantly altered metabolic pathways related to the urea cycle, which were characterized by reduced production of urea and polyamines and increased production of nitric oxide. Subsequently, we observed that activation of the p53 pathway may be the main cause of the above phenomena. The p53 inhibitor pifithrin-α partially restored the production of polyamines, but the mitochondrial morphology and function were still impaired. Further treatment of UT-B-overexpressing B16 cells with reactive oxygen species scavenging agent N-acetyl-l-cysteine and coenzyme Q10 restored cell viability and mitochondrial function and increased polyamine production. In conclusion, UT-B overexpression caused mitochondrial dysfunction and increased oxidative stress in B16 cells, and then activated p53 expression, which may be one of the mechanisms leading to the decrease in intracellular polyamines.

Spherical silver oxide nanoparticles for fabrication of electrochemical sensor for efficient 4-Nitrotoluene detection and assessment of their antimicrobial activity

This research article reports an economic and affordable microwave-assisted synthesis of spherical silver oxide nanoparticles (Ag₂O NPs) (80-90 nm) for an efficient electrochemical sensing of a hazardous organic pollutant 4-nitrotoluene (4-NT). Such well-characterized Ag₂O NPs were utilized to modify gold (Au) electrode in order to fabricate Ag₂O-NPs/Au sensor to detect 4-NT using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) techniques. Ag₂O-NPs/Au sensor exhibited a distinguished electrical response as a function of varying 4-NT concentration in neutral medium samples. Ag₂O-NPs/Au sensor demonstrated an ultrahigh sensitivity as 15.33 μA (μM)^-1 cm^-2, a low detection limit of 62.3 nM, and linear response in detection ranges of 0.6-5.9 μM and 37-175 μM. The sensing performance of fabricated Ag₂O-NPs/Au sensor is reproducible, reusable, selective in presence of other chemical species, and validated using real samples. The Ag₂O/Au sensor had much rapid and easy fabrication process and offered much lower LOD for 4-NT detection than many previously reported sensors. Along with efficient electrochemical activity, the spherical Ag₂O NPs also exhibit remarkable antimicrobial activity against harmful gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus) bacteria. Herein projected efficient Ag₂O-NPs/Au electrochemical sensor for 4-NT is affordable with the capability of scaling up to perform point-of-care 4-NT testing needed for successful environmental monitoring and water quality assurance.

Full Characterization of the UV Hydrodebromination Products of the Current-Use Brominated Flame Retardants Hexabromobenzene, Pentabromotoluene, and Pentabromoethylbenzene

UV transformation was studied with three structurally closely related current-use brominated flame retardants (cuBFRs), i.e., hexabromobenzene (HBB), pentabromotoluene (PBT), and pentabromoethylbenzene (PBEB). Irradiation in toluene and benzotrifluoride (BTF) showed pseudo-first-order kinetics. Repeated high-performance liquid chromatographic (HPLC) fractionation, available reference standards, dedicated syntheses, gas chromatography with mass spectrometry (GC/MS), GC separation on two different phases including retention time rules based on dipole interactions, and proton magnetic resonance spectroscopy (¹H NMR) evaluation enabled a full structural characterization of all 22 transformation products formed by hydrodebromination. In addition to pentabromobenzene (only transformation product with five bromine), tetra- and tribrominated transformation products were predominantly formed in the case of all three cuBFRs. Hydrodebromination was favored by bromine removal from positions with a high Br density. Br → H exchange was about 3 times faster in positions flanked by two vicinal Br atoms. This favored pathway explained why hydrodebromination sharply dropped at the level of tribrominated cuBFRs because readily degradable precursors were no more available at this point. Hence, a full degradation of tribrominated and lower-brominated transformation products may only be achieved in combination with a different process such as microbial transformation.

Biochar-mediated reduction of m-nitrotoluene: Interaction between reduction of m-nitrotoluene and sequestration of contaminants

Biochar is a highly effective adsorbent for nitroaromatic compounds (NACs), and acts as an electron shuttle that mediates the reduction of NACs. Hence, when biochar is used to mediate NAC reduction, adsorption and reduction will occur simultaneously and affect each other. However, the effect of biochar-mediated NAC reduction on sorption remains unknown. Eight biochars with different physicochemical properties were used to adsorb m-nitrotoluene and mediate its reduction. The results showed that the adsorption of m-nitrotoluene onto the various biochars facilitated its reduction, whereas biochar-mediated reduction retarded and weakened contaminant adsorption, which increased the environmental risk posed by m-nitrotoluene. Nevertheless, biochars with a high graphitization degree and developed porosity not only had a great catalytic ability, but also significantly alleviated the negative effect of reduction on adsorption. This was ascribed to the π-π interaction and pore-filling effect, which played more important roles than the hydrophobic effect in adsorbing the reduction product (m-toluidine) onto the studied biochars during reduction. Furthermore, the methanol extraction results indicated that the eight biochars presented significantly stronger sequestration abilities for adsorbed m-toluidine than for adsorbed m-nitrotoluene. This resulted from the hydrogen bonding and the Lewis acid-base effect between m-toluidine and each biochar, which were absent for m-nitrotoluene. These results suggest that biochars with a high graphitization degree and developed porosity are applicable for mediating reduction-enhancing sequestration of NACs, which could be a novel strategy for NAC remediation.

Regulation of amyloid-β levels by matrix metalloproteinase-2/9 (MMP2/9) in the media of lung cancer cells

In this study, we set out to identify regulators of intact amyloid-β40/42 (Aβ) levels in A549 (p53 wild-type) and H1299 (p53-null) lung cancer cell media. Higher Aβ levels were detected in the media of A549 than H1299 cells without or with treatment with 4-methylumbelliferone (4-MU) and/or the anti-CD44 antibody (5F12). Using inhibitors, we found that PI3K, AKT, and NFκB are likely involved in regulating Aβ levels in the media. However, increased Aβ levels that more closely resembled those found upon 4-MU co-treatment resulted from MMP2/9 inhibition, suggesting that MMP2/9 maybe the main contributors to regulation of Aβ levels in the media. Differences in Aβ levels might be accounted for, in part, by p53 since blocking p53 function in A549 cells resulted in decreased Aβ levels, increased MMP2/9 levels, increased PI3K/AKT activities and the phospho/total NFκB ratio. Using siRNA targeted against MMP2 or MMP9, we found increased Aβ levels in the media, however, MMP2 knockdown led to Aβ levels closely mimicking those detected by co-treatment with 4-MU. Cell viability or apoptosis upon treatment with either MMP2 or MMP9 siRNA along with Aβ immunodepletion, showed that MMP2 is the predominant regulator of the cytotoxic effects induced by Aβ in lung cancer cells.

Synthesis of Polyfluorinated Thia- and Oxathiacalixarenes Based on Perfluoro-m-xylene

Perfluorinated tetrathiacalix[4]arene was obtained by heating perfluoro-m-xylene with thiourea or 2,5-difluoro-4,6-bis(trifluoromethyl)benzene-1,3-dithiol at 90 °C. Interaction of perfluoro-m-xylene with resorcinol or orcinol under mild conditions and subsequent heating of the mixture with 2,5-difluoro-4,6-bis(trifluoromethyl)benzene-1,3-dithiol leads to polyfluorinated dioxadithiacalix[4]arenes. Triphenyl and pentaphenyl ethers formed by the interaction of perfluoro-m-xylene with resorcinol under heating with thiourea gives polyfluorinated oxathiacalixarenes containing six and five aromatic nuclei, respectively.

A New Inhibitor of ADAM17 Composed of a Zinc-Binding Dithiol Moiety and a Specificity Pocket-Binding Appendage

A disintegrin and metalloproteinase 17 (ADAM17) is a zinc-dependent enzyme that catalyzes the cleavage of the extracellular domains of various transmembrane proteins. ADAM17 is regarded as a promising drug target for the suppression of various diseases, including cancer metastasis. We synthesized a new ADAM17 inhibitor, SN-4, composed of a zinc-binding dithiol moiety and an appendage that specifically binds to a pocket of ADAM17. We show that SN-4 inhibits the ability of ADAM17 to cleave tumor necrosis factor α (TNF-α) in vitro. This activity was reduced by the addition of zinc, indicating the importance of the zinc chelating dithiol moiety. Inhibition of TNF-α cleavage by SN-4 in cells was also observed, and with an IC50 of 3.22 µM, SN-4 showed slightly higher activity than the well-studied ADAM17 inhibitor marimastat. Furthermore, SN-4 was shown to inhibit cleavage of CD44 by ADAM17, but not by ADAM10, and to suppress cell invasion. Molecular docking showed good fitting of the specificity pocket-binding group and one SH of SN-4 and hinted at possible means of structural optimization. This study provides clues for the development of potent and selective ADAM17 inhibitors.

Application of P53 mRNA in signal transduction mechanisms of skeletal muscle cells

By analyzing the effects of P53 inhibitors and ladder climbing exercise on P53 mRNA transcription in skeletal muscle of mice, the application of P53 mRNA in signal transduction mechanism of skeletal muscle cells was studied. Several clean ICR mice were fed for experiment. The experimental mice were divided into groups to analyze the effect of P53 inhibitor on P53 mRNA transcription in gastrocnemius muscle of mice. The mice were randomly divided into The application of P53 mRNA in signal transduction mechanism of skeletal muscle cells was studied, and the corresponding endurance exercise program and ladder climbing training program were designed. According to the research, exercise is to some extent a stimulating factor affecting P53 inhibitor. Endurance training and injection of P53 inhibitor affect P53 mRNA content. Exercise has a benign effect on ICR mice injected with P53 inhibitor. The expression of P53 mRNA in skeletal muscle was significantly affected by climbing training in youth, and decreased by climbing training in old age. However, there was no difference between long-term climbing training and short-term climbing training in the expression of P53 mRNA in skeletal muscle.

Remediation of different nitroaromatic pollutants by a promising agent of Cupriavidus sp. strain a3

Nitrobenzene, nitrotoluenes and nitrobenzoic acid are toxic and mutagenic. Their removal from the environment is necessary to avoid health and environmental damage. In this study, Cupriavidus strain a3 was found to utilize 2-nitrotoluene (2NT), 3-nitrotoluene (3NT), 4-nitrotoluene (4NT), nitrobenzene (NB) and 2-nitrobenzoic acid (2NBA) as carbon and nitrogen source, resulting in their detoxification. The metabolism involved reductive transformation of nitroaromatics to the corresponding amines followed by cleavage of amino group to release ammonia. Cell free extract showed nitroreductase activity in the range of 310-389 units/mg. NB was reduced to form benzamine and 4-aminophenol, 2NT was reduced to 2-aminotoluene, whereas 2NBA was reduced to form 2-aminobenzoic acid. Similarly, 3NT was metabolized to 3-aminotoluene and 2-amino-4-methylphenol, while 4NT was reduced to 4-nitrosotoluene and 4-aminotoluene. Cytotoxicity and apoptosis assays using Jurkat cell line, and Ames test were used to evaluate the detoxification of nitroaromatics during biodegradation. Biodegradation with Cupriavidus resulted in 2.6-11 fold increase in cell viability, 1.3-2.3 fold reduction in apoptosis, 1.6-55 fold reduction in caspase-3 activation, and complete disappearance of mutagenic activity. In soil microcosm, bioaugmentation with Cupriavidus resulted in 16-59% degradation of various nitroaromatics, as against <14% degradation without bioaugmentation. Thus, the present study reflects promising capability of Cupriavidus strain a3 in degradation and detoxification of multiple nitroaromatics.

Thioredoxin-dependent control balances the metabolic activities of tetrapyrrole biosynthesis

Plastids are specialized organelles found in plants, which are endowed with their own genomes, and differ in many respects from the intracellular compartments of organisms belonging to other kingdoms of life. They differentiate into diverse, plant organ-specific variants, and are perhaps the most versatile organelles known. Chloroplasts are the green plastids in the leaves and stems of plants, whose primary function is photosynthesis. In response to environmental changes, chloroplasts use several mechanisms to coordinate their photosynthetic activities with nuclear gene expression and other metabolic pathways. Here, we focus on a redox-based regulatory network composed of thioredoxins (TRX) and TRX-like proteins. Among multiple redox-controlled metabolic activities in chloroplasts, tetrapyrrole biosynthesis is particularly rich in TRX-dependent enzymes. This review summarizes the effects of plastid-localized reductants on several enzymes of this pathway, which have been shown to undergo dithiol-disulfide transitions. We describe the impact of TRX-dependent control on the activity, stability and interactions of these enzymes, and assess its contribution to the provision of adequate supplies of metabolic intermediates in the face of diurnal and more rapid and transient changes in light levels and other environmental factors.

A novel soybean protein disulphide isomerase family protein possesses dithiol oxidation activity: identification and characterization of GmPDIL6

Secretory and membrane proteins synthesized in the endoplasmic reticulum (ER) are folded with intramolecular disulphide bonds, viz. oxidative folding, catalysed by the protein disulphide isomerase (PDI) family proteins. Here, we identified a novel soybean PDI family protein, GmPDIL6. GmPDIL6 has a single thioredoxin-domain with a putative N-terminal signal peptide and an active centre (CKHC). Recombinant GmPDIL6 forms various oligomers binding iron. Oligomers with or without iron binding and monomers exhibited a dithiol oxidase activity level comparable to those of other soybean PDI family proteins. However, they displayed no disulphide reductase and extremely low oxidative refolding activity. Interestingly, GmPDIL6 was mainly expressed in the cotyledon during synthesis of seed storage proteins and GmPDIL6 mRNA was up-regulated under ER stress. GmPDIL6 may play a role in the formation of disulphide bonds in nascent proteins for oxidative folding in the ER.

THOC1 deficiency leads to late-onset nonsyndromic hearing loss through p53-mediated hair cell apoptosis

Apoptosis of cochlear hair cells is a key step towards age-related hearing loss. Although numerous genes have been implicated in the genetic causes of late-onset, progressive hearing loss, few show direct links to the proapoptotic process. By genome-wide linkage analysis and whole exome sequencing, we identified a heterozygous p.L183V variant in THOC1 as the probable cause of the late-onset, progressive, non-syndromic hearing loss in a large family with autosomal dominant inheritance. Thoc1, a member of the conserved multisubunit THO/TREX ribonucleoprotein complex, is highly expressed in mouse and zebrafish hair cells. The thoc1 knockout (thoc1 mutant) zebrafish generated by gRNA-Cas9 system lacks the C-startle response, indicative of the hearing dysfunction. Both Thoc1 mutant and knockdown zebrafish have greatly reduced hair cell numbers, while the latter can be rescued by embryonic microinjection of human wild-type THOC1 mRNA but to significantly lesser degree by the c.547C>G mutant mRNA. The Thoc1 deficiency resulted in marked apoptosis in zebrafish hair cells. Consistently, transcriptome sequencing of the mutants showed significantly increased gene expression in the p53-associated signaling pathway. Depletion of p53 or applying the p53 inhibitor Pifithrin-α significantly rescued the hair cell loss in the Thoc1 knockdown zebrafish. Our results suggested that THOC1 deficiency lead to late-onset, progressive hearing loss through p53-mediated hair cell apoptosis. This is to our knowledge the first human disease associated with THOC1 mutations and may shed light on the molecular mechanism underlying the age-related hearing loss.

From Riluzole to Dexpramipexole via Substituted-Benzothiazole Derivatives for Amyotrophic Lateral Sclerosis Disease Treatment: Case Studies

The 1,3-benzothiazole (BTZ) ring may offer a valid option for scaffold-hopping from indole derivatives. Several BTZs have clinically relevant roles, mainly as CNS medicines and diagnostic agents, with riluzole being one of the most famous examples. Riluzole is currently the only approved drug to treat amyotrophic lateral sclerosis (ALS) but its efficacy is marginal. Several clinical studies have demonstrated only limited improvements in survival, without benefits to motor function in patients with ALS. Despite significant clinical trial efforts to understand the genetic, epigenetic, and molecular pathways linked to ALS pathophysiology, therapeutic translation has remained disappointingly slow, probably due to the complexity and the heterogeneity of this disease. Many other drugs to tackle ALS have been tested for 20 years without any success. Dexpramipexole is a BTZ structural analog of riluzole and was a great hope for the treatment of ALS. In this review, as an interesting case study in the development of a new medicine to treat ALS, we present the strategy of the development of dexpramipexole, which was one of the most promising drugs against ALS.

Spiro-containing derivatives show antiparasitic activity against Trypanosoma brucei through inhibition of the trypanothione reductase enzyme

Trypanothione reductase (TR) is a key enzyme that catalyzes the reduction of trypanothione, an antioxidant dithiol that protects Trypanosomatid parasites from oxidative stress induced by mammalian host defense systems. TR is considered an attractive target for the development of novel anti-parasitic agents as it is essential for parasite survival but has no close homologue in humans. We report here the identification of spiro-containing derivatives as inhibitors of TR from Trypanosoma brucei (TbTR), the parasite responsible for Human African Trypanosomiasis. The hit series, identified by high throughput screening, was shown to bind TbTR reversibly and to compete with the trypanothione (TS₂) substrate. The prototype compound 1 from this series was also found to impede the growth of Trypanosoma brucei parasites in vitro. The X-ray crystal structure of TbTR in complex with compound 1 solved at 1.98 Å allowed the identification of the hydrophobic pocket where the inhibitor binds, placed close to the catalytic histidine (His 461’) and lined by Trp21, Val53, Ile106, Tyr110 and Met113. This new inhibitor is specific for TbTR and no activity was detected against the structurally similar human glutathione reductase (hGR). The central spiro scaffold is known to be suitable for brain active compounds in humans thus representing an attractive starting point for the future treatment of the central nervous system stage of T. brucei infections.

Trypanosoma brucei is a parasite responsible for neglected pathologies such as human African trypanosomiasis, also known as sleeping sickness. This disease is endemic in sub-Saharan Africa, with 70 million people at risk of infection. Current treatments for this type of disease are limited by their toxicity, administration in endemic countries and treatment resistance. Therapies against infectious diseases typically rely on targeting one or more components of the parasite that are not present in humans to ensure the best possible therapeutic window. In this case we aimed at targeting the Trypanosoma brucei trypanothione reductase (TR), one enzyme that synthesize the reduced trypanothione a key molecule for preserving the parasite redox balance. This enzyme does not exist in humans that have glutathione instead of trypanothione. Past attempts to identify novel inhibitors of this target has failed to generate drug-like molecules. To overcome this limitation we employed a recent, higher quality, TR activity assay to test a collection of compounds previously reported to be active against these parasites. This approach led to the identification and validation of a new chemotype with a unique mode of inhibition of TR. This chemical series is a drug-like starting point, in fact its core (spiro) is present in drugs approved for human use.

The p53 inactivators pifithrin-μ and pifithrin-α mitigate TBI-induced neuronal damage through regulation of oxidative stress, neuroinflammation, autophagy and mitophagy

Traumatic brain injury (TBI) is one of the most common causes of death and disability worldwide. We investigated whether inhibition of p53 using pifithrin (PFT)-α or PFT-μ provides neuroprotective effects via p53 transcriptional dependent or -independent mechanisms, respectively. Sprague Dawley rats were subjected to controlled cortical impact TBI followed by the administration of PFTα or PFT-μ (2 mg/kg, i.v.) at 5 h after TBI. Brain contusion volume, as well as sensory and motor functions were evaluated at 24 h after TBI. TBI-induced impairments were mitigated by both PFT-α and PFT-μ. Fluoro-Jade C staining was used to label degenerating neurons within the TBI-induced cortical contusion region that, together with Annexin V positive neurons, were reduced by PFT-μ. Double immunofluorescence staining similarly demonstrated that PFT-μ significantly increased HO-1 positive neurons and mRNA expression in the cortical contusion region as well as decreased numbers of 4-hydroxynonenal (4HNE)-positive cells. Levels of mRNA encoding for p53, autophagy, mitophagy, anti-oxidant, anti-inflammatory related genes and proteins were measured by RT-qPCR and immunohistochemical staining, respectively. PFT-α, but not PFT-μ, significantly lowered p53 mRNA expression. Both PFT-α and PFT-μ lowered TBI-induced pro-inflammatory cytokines (IL-1β and IL-6) mRNA levels as well as TBI-induced autophagic marker localization (LC3 and p62). Finally, treatment with PFT-μ mitigated TBI-induced declines in mRNA levels of PINK-1 and SOD2. Our data suggest that both PFT-μ and PFT-α provide neuroprotective actions through regulation of oxidative stress, neuroinflammation, autophagy, and mitophagy mechanisms, and that PFT-μ, in particular, holds promise as a TBI treatment strategy.

Effect of Polymerization Accelerator on Bond Strength to Eugenol-Contaminated Dentin

PURPOSE

To evaluate the effect of a polymerization accelerator on the microtensile bond strength (µTBS) of etch-and-rinse and self-etch adhesives to eugenol-contaminated dentin.

MATERIALS AND METHODS

Sixty flat dentin surfaces were prepared from human molars. Half of the specimens were restored with zinc oxide eugenol temporary cement (IRM) (eugenol-contaminated group) and the other half remained without restoration (control group). After 24-h storage, the cement was mechanically removed. Then the specimens in each group were further divided into three subgroups based on the application procedure of a polymerization accelerator (p-toluenesulfinic acid sodium salt; Accel): no application, 10-s application, or 30-s application. After air drying, the dentin surfaces were bonded with either a three-step etch-and-rinse adhesive (OptiBond FL) or a two-step self-etch adhesive (Clearfil SE Bond) and restored with composite. After 24-h water storage, the bonded specimens were subjected to the µTBS test. Data were analyzed by three-way ANOVA and Dunnett's T3 test (p < 0.05).

RESULTS

The eugenol-contaminated groups had significantly lower µTBS than the control groups with both types of adhesives (p < 0.05), and the application of Accel significantly increased the compromised µTBS to eugenol-contaminated dentin. Optibond FL presented significantly higher µTBS to eugenol-contaminated dentin than did Clearfil SE Bond (p < 0.05).

CONCLUSION

The application of a polymerization accelerator on eugenol-contaminated dentin prior to adhesive resin application increased the μTBS of both the three-step etch-and-rinse and two-step self-etch adhesive.

Distribution characteristics and ecological evaluation of chlorobenzene compounds in surface sediment of the Maowei Sea, Guangxi, China

To enhance our understanding on environmental conditions of the Maowei Sea in Guangxi province, China, the concentration and distribution of 22 chlorobenzene compounds (CBs) in the surface sediment were determined by gas chromatography-mass spectrometry (GC-MS). The relationship of the sediment between CBs and total organic carbon (TOC) was also investigated. The results showed that a total of eight kinds of CBs compounds were detected in the sediment samples which were collected from the coastal environment of the Maowei Sea, with an average concentration of 15.3 ng·g^-1 (the concentration range, 2.5-61.5 ng·g^-1). The rank of their average concentrations was as follows: 2,3,4,5,6-pentachlorotoluene > hexachlorobenzene, 2-chlorotoluene, 3-chlorotoluene and 2,3-dichlorotoluene > 2,4-dichlorotoluene > 4-chlorotoluene > pentachlorobenzene. Most CBs were distributed in sediments along the east coast of the Maowei Sea. For total TOC content in sediments, the concentration in the sampling locations was similar, with a mean concentration of 8.83 g·kg^-1 (the concentration range, 4.87-20.13 g·kg^-1). However, there was no significant correlation between the concentration of TOC and total CBs. Compared to the corresponding CBs in the sediment of other coastal areas in mainland China and other countries, the value of CBs in the Maowei Sea was low.

Novel brominated flame retardant (NBFR) concentrations and spatial distributions in global fishmeal

Novel brominated flame retardants (NBFRs), which are lipophilic compounds that have been widely applied after the phasing-out of legacy BFRs, can bioaccumulate through the food chain. However, information on NBFRs in animal feeds, the beginning of farm-to-fork pathway, is very limited. Fishmeal is one of the most widely applied feedstuff worldwide. The present study identified eleven NBFRs from ninety-two globally collected fishmeal samples with levels in the range of 0.13-822 (mean: 15.1 ± 85.5) ng/g lipid weight (lw). Hexabromobenzene (HBB) and pentabromotoluene (PBT) were the most prevalent contributors (detection frequencies: 95.7% and 73.9%, respectively), and decabromodiphenylethane (DBDPE) was the weightiest contributor (accounted for 67.1% of the ΣNBFRs, mean: 12.1 ± 84.8 ng/g lw). From a geographical view, the highest NBFR level was found in Chinese fishmeal. The NBFRs fell within an order of magnitude in South America, Southeast Asia, Europe and United States. DBDPE was predominant in the fishmeal collected from China, South America and United States, but it was not detected in European fishmeal. The NBFR levels are significantly lower compared to the polybrominated diphenyl ethers (PBDEs) (p < 0.01), indicating that the distribution of NBFRs was not as wide as PBDEs in fishmeal. DBDPE was significantly correlated with BDE209 (r = 0.557, p < 0.01), which implies that the two chemicals might have similar sources. Quantitative structure-activity relationship (QSAR)results imply that the NBFRs might have similar persistence and biomagnification potential as legacy lipophilic POPs.

Acute kidney injury induces dramatic p21 upregulation via a novel, glucocorticoid-activated, pathway

The cyclin kinase inhibitor p21 is acutely upregulated during acute kidney injury (AKI) and exerts cytoprotective effects. A proposed mechanism is oxidant stress-induced activation of p53, the dominant p21 transcription factor. Glycerol-induced rhabdomyolysis induces profound renal oxidant stress. Hence, we studied this AKI model to determine whether p53 activation corresponds with p21 gene induction and/or whether alternative mechanism(s) might be involved. CD-1 mice were subjected to glycerol-induced AKI. After 4 or 18 h, plasma, urinary, and renal cortical p21 protein and mRNA levels were assessed. Renal p53 activation was gauged by measurement of both total and activated (Ser15-phosphorylated) p53 and p53 mRNA levels. Glycerol evoked acute, progressive increases in renal cortical p21 mRNA and protein levels. Corresponding plasma (~25-fold) and urinary (~75-fold) p21 elevations were also observed. Renal cortical ratio of total to phosphorylated (Ser15) p53 rose three- to fourfold. However, the p53 inhibitor pifithrin-α failed to block glycerol-induced p21 gene induction, suggesting that an alternative p21 activator might also be at play. To this end, it was established that glycerol-induced AKI 1) dramatically increased plasma (~5-fold) and urinary (~75-fold) cortisol levels, 2) the glucocorticoid receptor antagonist mifepristone blocked glycerol-induced p21 mRNA and protein accumulation, and 3) dexamethasone or cortisol injections markedly increased p21 protein and mRNA in both normal and glycerol-treated mice, although no discernible p53 protein or mRNA increases were observed. We conclude that AKI-induced "systemic stress" markedly increases plasma and urinary cortisol, which can then activate renal p21 gene expression, at least in part, via a glucocorticoid receptor-dependent signaling pathway. Discernible renal cortical p53 increases are not required for this dexamethasone-mediated p21 response.

In Vitro and in Vivo Effect of MAPK Signal Transduction Pathway Inhibitors on Echinococcus multilocularis

To evaluate the effect of mitogen-activated protein kinase (MAPK) signal transduction pathway inhibitors against alveolar echinococcosis in vitro and in vivo, Echinococcus multilocularis metacestode cysts and protoscolices were obtained from infected mice. Protein chip technology was utilized to screen for key highly expressed target proteins in the MAPK pathway in this parasite and their corresponding inhibitors. Four-week-old Balb/c female mice used for the in vivo experiment underwent inoculation of E. multilocularis by intraperitoneal injection, as well as intragastric administration of MAPK inhibitors for 6 wk. We included 6 groups of mice: a phosphate-buffered saline (PBS) group (negative control); an albendazole-treated group (positive group); and 4 experimental groups treated with TRx0237 mesylate, GDC-0994, pifithrin-β hydrobromide, or Selonsertib. Echinococcus multilocularis protoscolices were collected and cultured in 1066 medium with penicillin/streptomycin and 10% fetal bovine serum. The in vitro experiment included a PBS group (negative control), a dimethyl sulfoxide-treated group (solvent group), and 4 inhibitor-treated groups as in the in vivo experiment (experimental groups). Each inhibitor group received 4 drug concentrations (5, 30, 55, and 80 μM), and the experiment was performed in triplicate per sample. Fluorescence microscopy was used to evaluate the survival rate of the protoscolices every 48 hr beginning from the first 24 hr. The same grouping was used to evaluate cytotoxicity on E. multilocularis germinal cells and L02 cells. The average weights of E. multilocularis metacestode cyst tissue from each group of the in vivo experiment were 873 mg (PBS), 335 mg (albendazole), 323 mg (TRx0237 mesylate), 420 mg (GDC-0994), 340 mg (pifithrin-β hydrobromide), and 642 mg (Selonsertib). Results showed albendazole, TRx0237 mesylate, and pifithrin-β hydrobromide had significant inhibitory effects on inhibition of E. multilocularis. We found a positive correlation between drug concentrations and the inhibitory effects seen in the in vitro experiment, with the differences in contrast with the control group becoming statistically significant after 72 hr of treatment ( P < 0.05). The inhibition rates of TRx0237 mesylate to germinal cells by drug concentration were 23.73, 46.59, 74.71, and 77.44%. Other drugs had no effect on germinal cells. All the inhibitors had low toxicity on L02 cells. Inhibitors of the MAPK signal transduction pathway showed significant inhibitory effects on E. multilocularis, suggesting these may be potential candidates for the treatment of alveolar echinococcosis.

Degradable redox-responsive disulfide-based nanogel drug carriers via dithiol oxidation polymerization

Stimuli-responsive nanogels are important drug and gene carriers that mediate the controlled release of therapeutic molecules. Herein, we report the synthesis of fully degradable disulfide cross-linked nanogel drug carriers formed by oxidative radical polymerization of 2,2'-(ethylenedioxy)diethanethiol (EDDET) as a monomer with different cross-linkers, including pentaerythritol tetramercaptoacetate (PETMA). Because the poly(EDDET) backbone repeat structure and cross-linking junctions are composed entirely of disulfide bonds, these nanogels specifically degrade to small molecule dithiols intracellularly in response to the reducing agent glutathione present inside of cells. Cross-linked nanogels were synthesized using controlled microfluidic mixing in the presence of a nonionic Pluronic surfactant PLU-127 to increase the nanogel stability. Adjusting the monomer to cross-linker ratio from 5 : 1 to 100 : 1 (mol/mol) tuned the cross-linking density, resulting in swelling ratios from 1.65 to >3. Increasing the amount of stabilizing Pluronic surfactant resulted in a decrease of nanogel diameter, as expected due to increased surface area of the resulting nanogels. The monomer to cross-linker ratio in the feed had no effect on the formed nanogel diameter, providing a way to control cross-linking density with constant nanogel size but tunable drug release kinetics. Nanogels exhibited an entrapment efficiency of up to 75% for loading of Rhodamine B dye. In vitro studies showed low cytotoxicity, quick uptake, and fast degradation kinetics. Due to the ease of synthesis, rapid gelation times, and tunable functionality, these non-toxic and fully degradable nanogels offer potential for use in a variety of drug delivery applications.

Tumor suppressor protein p53 negatively regulates ischemia-induced angiogenesis and arteriogenesis

OBJECTIVE

The tumor suppressor protein p53 regulates angiogenesis and is a key regulatory mediator of cellular apoptosis, proliferation, and growth. p53 expression is induced in response to ischemia; however, its role in regulating ischemia-induced angiogenesis and arteriogenesis remains undefined. The objective of this study was to define the role of p53 in regulating ischemia-induced angiogenesis and arteriogenesis and to identify mechanisms by which this regulation occurs in vivo.

METHODS

Surgically induced hindlimb ischemia or mesenteric artery ligation was performed in wild-type (p53+/+) and p53 knockout (p53-/-) mice. Limb perfusion and revascularization were assessed by laser Doppler perfusion imaging, capillary density, and collateral artery development. Mesenteric collateral artery flow and development were determined by arterial flow measurement and by histologic analysis, respectively. An in vitro aortic ring assay was performed on p53+/+ and p53-/- aortic tissue to evaluate endothelial function. The p53 inhibitor and activator pifithrin-α and quinacrine, respectively, were used to modulate p53 activity in vivo after ischemia.

RESULTS

Absence of p53 in mice resulted in increased limb perfusion (P < .05), capillary density (P < .05), and collateral artery development (P < .05) after induction of hindlimb ischemia. In the nonischemic mesenteric artery ligation model of arteriogenesis, p53 expression was induced in collateral arteries and increased arterial blood flow in mice lacking p53 (P < .05). Lack of p53 decreased apoptosis in ischemic hindlimb tissue (P < .05) and increased proangiogenic factors hypoxia-inducible factor 1α and vascular endothelial growth factor (VEGF). Endothelial cell outgrowth in vitro increased in the absence of p53 (P < .05). Pharmacologic augmentation of p53 expression after ischemia impaired perfusion and collateral artery formation and decreased VEGF levels (P < .05). Conversely, inhibition of p53 with pifithrin-α augmented limb perfusion (P < .05) and collateral artery formation (P < .05) and increased protein levels of hypoxia-inducible factor 1α and VEGF. Pharmacologic augmentation and inhibition of p53 had no significant effect in mice lacking p53.

CONCLUSIONS

p53 negatively regulates ischemia-induced angiogenesis and arteriogenesis. Inhibition of p53 increases ischemia-induced arteriogenesis and limb perfusion and thus represents a potential therapeutic strategy for arterial occlusive disease.

Novel Role of p53 in Septic Immunosuppression: Involvement in Loss and Dysfunction of CD4+ T Lymphocytes

BACKGROUND/AIMS

Immunosuppression frequently occurs during the development of sepsis and is closely associated with poor outcome. Characteristics of immunosuppressive CD4+ T lymphocytes in sepsis have been reported to include dramatic cell loss and inactivation. p53 acts as a pivotal transcription factor in regulating cell proliferation and apoptosis, which control tumorigenesis. However, few studies have investigated the universal role of p53 in immune cells, especially in the development of sepsis.

METHODS

A mouse model of sepsis was produced by cecal ligation and puncture (CLP), and isolated splenic CD4+ T cells or Jurkat cells were exposed to lipopolysaccharide (LPS) stimulation in vitro. We used genetic knockout (p53-/-) mice or the specific inhibitor pifithrin-α (PFT) to investigate the regulatory mechanisms of p53. Cell proliferation ability was assessed using a Cell Counting Kit-8 assay, and apoptotic cells were stained with annexin V/propidium iodide and then analyzed using a FACScan flow cytometer. Protein and mRNA expression levels were measured by western blotting and real-time PCR, and cytokine levels in culture supernatants were determined by enzyme-linked immunosorbent assay.

RESULTS

Splenic CD4+ T lymphocytes from CLP mice expressed gradually elevated p53 mRNA and protein levels, which resulted in extracellular regulated protein kinase 1/2 inactivation and expression of apoptotic molecules. Specific inhibition of p53 by PFT or genetic knockout (p53-/-) maintained CD4+ T lymphocyte homeostasis, as indicated by protection from cell loss and restoration of immune function. A medium dose of PFT improved the survival rate of mice, while mortality rate showed only a slight improvement in p53-/- mice compared with wild-type mice. The in vitro responses to LPS were consistent with these results, and upregulation of p53 clearly affected the proliferation, apoptosis, and immune dysfunction of CD4+ T lymphocytes. In addition, we confirmed the regulatory effect of p53 in Jurkat cells, and inhibition of p53 by either inhibition or short hairpin RNA transduction markedly protected cells from LPS stimulation.

CONCLUSION

Elevation of p53 in T lymphocytes during sepsis or endotoxin challenge might be responsible for inhibiting cell proliferation and enhancing both apoptosis and immune dysfunction of T cells.

Biodegradation of gaseous emissions of 2-chlorotoluene by strains of Rhodococcus sp. in polyurethane foam packed biotrickling filters

About 60,000-70,000 tons of 2-chlorotoluene, which shows high toxicity in aquatic ecosystems, are produced worldwide and used in a tremendous field of applications. However, clear proofs of biodegradation were only presented for Comamonas testosteroni KT5 and Rhodococcus sp. OCT10. Hence, this study aims on the isolation of additional strains and their characterization in pilot-scale biotrickling filters. Three strains named OCT2, OCT9, and OCT14 of the genus Rhodococcus were isolated, able to mineralize gaseous 2-chlorotoluene like the previously isolated strain Rhodococcus sp. OCT10. The performance levels of these strains were tested in four biotrickling filters each containing 18.8 L of polyurethane foam package, showing elimination capacities of carbon (C) of 30.9 (OCT2), 30.1 (OCT9), 32.2 (OCT10), and 3.9 g C·m^-3·h^-1 (OCT14) at an average crude gas level of 397.6 mg C·m^-3 and an empty bed residence time (EBRT) of 22.6 s. Since OCT10 showed the highest performance levels, this strain was characterized in a second biotrickling filter configuration at long-term conditions of 985 days, varying crude gas levels, EBRT and nutrient supply. Chloride balancing showed a recovery of 94.4% of 2-chlorotoluene eliminated out of the gas phase, pointing out mineralization of 2-chlorotoluene. German emission limit values were met at crude gas levels up to 750 mg C·m^-3 at EBRTs of 120 s or higher. The maximum elimination capacity was 51.2 g C·m^-3·h^-1 at a specific freight of 51.9 g C·m^-3·h^-1 and an EBRT of 254 s. Performance levels were strongly boosted by addition of ammonia as nutrient and stabilized at efficiency levels higher than 90% at a feed rate of 4 g ammonium sulfate per week and 100 L of package volume. Repetitive monitoring of the established 2-chlorotoluene degrading community by BOX-PCR fingerprinting revealed a high long-term stability of OCT10, underlining its suitability in this kind of application.

Chemical application strategies to protect water quality

Management of turfgrass on golf courses and athletic fields often involves application of plant protection products to maintain or enhance turfgrass health and performance. However, the transport of fertilizer and pesticides with runoff to adjacent surface waters can enhance algal blooms, promote eutrophication and may have negative impacts on sensitive aquatic organisms and ecosystems. Thus, we evaluated the effectiveness of chemical application setbacks to reduce the off-site transport of chemicals with storm runoff. Experiments with water soluble tracer compounds confirmed an increase in application setback distance resulted in a significant increase in the volume of runoff measured before first off-site chemical detection, as well as a significant reduction in the total percentage of applied chemical transported with the storm runoff. For example, implementation of a 6.1 m application setback reduced the total percentage of an applied water soluble tracer by 43%, from 18.5% of applied to 10.5% of applied. Evaluation of chemographs revealed the efficacy of application setbacks could be observed with storms resulting in lesser (e.g. 100 L) and greater (e.g. > 300 L) quantities of runoff. Application setbacks offer turfgrass managers a mitigation approach that requires no additional resources or time inputs and may serve as an alternative practice when buffers are less appropriate for land management objectives or site conditions. Characterizing potential contamination of surface waters and developing strategies to safeguard water quality will help protect the environment and improve water resource security. This information is useful to grounds superintendents for designing chemical application strategies to maximize environmental stewardship. The data will also be useful to scientists and regulators working with chemical transport and risk models.

Synthesis of N-aryl substituted p-toluenesulphonamides via nickel catalyzed amidation reaction and their antibacterial, antifungal and antioxidant activities evaluation

In present study nickel catalyzed synthesis of N-(aryl) substituted p-toluene sulphonamides is reported. The intermediate 4-methylbenzenesulphonamide (2) was obtained by the reaction between p-toluene sulphonyl chloride and ammonium hydroxide. Various readily available aryl halides (3a-e) Substituted p-toluene sulphonamides (4a-e) were obtained by coupling 4-methylbenezenesulphonamide (2) with via Buchwald-Hartwig cross-coupling reaction. Chemical structures of synthesized compounds were confirmed using Fourier Transform Infrared (FT-1R), proton and carbon-13 Nuclear Magnetic Resonance (1H-NMR and 13C-NMR) and mass spectroscopy. The new compounds were screened for antibacterial and antifungal activities against Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, salmonella typhi, candida albicans and Aspergillusniger using agar diffusion technique. Some of the compounds showed higher activity when compared with the standards ciprofloxacin and ketoconazole). The sulphonamides were further screened for antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl, Ferrous sulphate lipid per oxidation and Ferric reducing antioxidant power and the compound showed good antioxidant activity. Tests such as acute toxicity, liver function and kidney function was also carried out on the synthesized compounds.

Phytochemical Analysis of Anti-Inflammatory and Antioxidant Effects of Mahonia aquifolium Flower and Fruit Extracts

Oxidative stress and inflammation are interlinked processes. The aim of the study was to perform a phytochemical analysis and to evaluate the antioxidant and anti-inflammatory activities of ethanolic Mahonia aquifolium flower (MF), green fruit (MGF), and ripe fruit (MRF) extracts. Plant extract chemical composition was evaluated by HLPC. A DPPH test was used for the in vitro antioxidant activity. The in vivo antioxidant effects and the anti-inflammatory potential were tested on a rat turpentine oil-induced inflammation, by measuring serum nitric oxide (NOx) and TNF-alpha, total oxidative status (TOS), total antioxidant reactivity (TAR), oxidative stress index (OSI), 3-nitrothyrosine (3NT), malondialdehyde (MDA), and total thiols (SH). Extracts were administrated orally in three dilutions (100%, 50%, and 25%) for seven days prior to inflammation. The effects were compared to diclofenac. The HPLC polyphenol and alkaloid analysis revealed chlorogenic acid as the most abundant compound. All extracts had a good in vitro antioxidant activity, decreased NOx, TOS, and 3NT, and increased SH. TNF-alpha was reduced, and TAR increased only by MF and MGF. MDA was not influenced. Our findings suggest that M. aquifolium has anti-inflammatory and antioxidant effects that support the use in primary prevention of the inflammatory processes.

MG132 plus apoptosis antigen-1 (APO-1) antibody cooperate to restore p53 activity inducing autophagy and p53-dependent apoptosis in HPV16 E6-expressing keratinocytes

The E6 oncoprotein can interfere with the ability of infected cells to undergo programmed cell death through the proteolytic degradation of proapoptotic proteins such as p53, employing the proteasome pathway. Therefore, inactivation of the proteasome through MG132 should restore the activity of several proapoptotic proteins. We investigated whether in HPV16 E6-expressing keratinocytes (KE6 cells), the restoration of p53 levels mediated by MG132 and/or activation of the CD95 pathway through apoptosis antigen-1 (APO-1) antibody are responsible for the induction of apoptosis. We found that KE6 cells underwent apoptosis mainly after incubation for 24 h with MG132 alone or APO-1 plus MG132. Both treatments activated the extrinsic and intrinsic apoptosis pathways. Autophagy was also activated, principally by APO-1 plus MG132. Inhibition of E6-mediated p53 proteasomal degradation by MG132 resulted in the elevation of p53 protein levels and its phosphorylation in Ser46 and Ser20; the p53 protein was localized mainly at nucleus after treatment with MG132 or APO-1 plus MG132. In addition, induction of its transcriptional target genes such as p21, Bax and TP53INP was observed 3 and 6 h after treatment. Also, LC3 mRNA was induced after 3 and 6 h, which correlates with lipidation of LC3B protein and induction of autophagy. Finally, using pifithrin alpha we observed a decrease in apoptosis induced by MG132, and by APO-1 plus MG132, suggesting that restoration of APO-1 sensitivity occurs in part through an increase in both the levels and the activity of p53. The use of small molecules to inhibit the proteasome pathway might permit the activation of cell death, providing new opportunities for CC treatment.

Photodegradation of some brominated and phenolic micropollutants in raw hospital wastewater with CeO2 and TiO2 nanoparticles

In this study, the degradations of 2,3,4,5,6-pentabromotoluene (PBT), 2,3,4,5,6-pentabromoethyl benzene (PBEB), triclosan (TCS) and gemfibrozil (GFZ) in raw hospital wastewater were investigated with cerium (IV) oxide and titanium (IV) oxide nanoparticles considering the mechanisms of adsorption, photolysis, and photocatalysis with UV-C lamps. The effects of nano-CeO₂ and nano-TiO₂ concentrations, irradiation times, UV light powers and hospital wastewater pH on the photodegradation yields of micropollutants namely PBT, PBEB, TCS and GFZ were investigated throughout photocatalysis. The nano-TiO₂ produced had an anatase phase with crystalline shape with a surface area of 205 m² g^-1 and an average size of 11.50 nm. The CeO₂ nanoparticles had a spherical shape with a higher surface area (302 m² g^-1) than that of TiO₂ and a lower average size (8.11 nm). It was found that the removals of PBT, PBEB, TCS and GFZ with adsorption (5.7%-17.1%) and photolysis (9.0%-15.9%) were not significant for both nanoparticles. The photodegradation of PBT (92%), PBEB (90%), TCS (97%) and GFZ (95%) with nano-CeO₂ gave better results than nano-TiO₂ (90%, 87%, 94% and 93% for PBT, PBEB, TCS and GFZ, respectively) under optimum experimental conditions (0.50 g L^-1 nano-CeO_2, 45 min irradiation time, 25 °C temperature, pH = 8.50, 210 W UV light power). Both nanoparticles were reused effectively after photo-removals of the micropollutants from the hospital wastewater. The lowest photodegradation yields were 80%, 78%, 75% and 74% for TCS, GFZ, PBT and PBEB, respectively, with nano-TiO₂ after six sequential treatments. The lowest photodegradation yields were 86%, 83%, 80% and 79% for the same micropollutants, respectively, with nano-CeO₂ after six sequential treatments. The cost to treat 1 m³ raw hospital wastewater were 8.70 € and 2.28 €, for the photocatalytic treatments with nano-TiO₂ and nano-CeO₂, respectively.

CF2H, a Hydrogen Bond Donor

The CF₂H group, a potential surrogate for the OH group, can act as an unusual hydrogen bond donor, as confirmed by crystallographic, spectroscopic, and computational methods. Here, we demonstrate the bioisosterism of the OH and CF₂H groups and the important roles of CF₂-H···O hydrogen bonds in influencing intermolecular interactions and conformational preferences. Experimental evidence, corroborated by theory, reveals the distinctive nature of CF₂H hydrogen bonding interactions relative to their normal OH hydrogen bonding counterparts.

MgAl layered double hydroxide/chitosan porous scaffolds loaded with PFTα to promote bone regeneration

Poor bone formation remains a key risk factor associated with acellular scaffolds that occurs in some bone defects, particularly in patients with metabolic bone disorders and local osteoporosis. We herein fabricated for the first time layered double hydroxide-chitosan porous scaffolds loaded with PFTα (LDH-CS-PFTα scaffolds) as therapeutic bone scaffolds for the controlled release of PFTα to enhance stem cell osteogenic differentiation and bone regeneration. The LDH-CS scaffolds had three-dimensional interconnected macropores, and plate-like LDH nanoparticles were uniformly dispersed within or on the CS films. The LDH-CS scaffolds exhibited appropriate PFTα drug delivery due to hydrogen bonding among LDH, CS and PFTα. In vitro functional studies demonstrated that the PFTα molecules exhibited potent ability to induce osteogenesis of hBMSCs via the GSK3β/β-catenin pathway, and the LDH-CS-PFTα scaffolds significantly enhanced the osteogenic differentiation of hBMSCs. In vivo studies revealed significantly increased repair and regeneration of bone tissue in cranial defect model rats compared to control rats at 12 weeks post-implantation. In conclusion, the LDH-CS-PFTα scaffolds exhibited excellent osteogenic differentiation and bone regeneration capability and hold great potential for applications in defined local bone regeneration.

Protective role of p53 in acetaminophen hepatotoxicity

p53 is a tumor suppressor with a pro-death role in many conditions. However, in some contexts, evidence supports a pro-survival function. p53 has been shown to be activated in acetaminophen (APAP) toxicity but the impact of this on toxicity is uncertain. In the present study, we have found that p53 plays a protective role in APAP-induced liver injury. We inhibited p53 using three different approaches in mice, pifithrin-α (PFTα), knockdown of p53 expression with antisense oligonucleotide, and p53 knockout. Mice were treated with APAP (300mg/kg) i.p. and after 24h in all three conditions, the liver injury was more severe as reflected in higher ALT levels and great area of necrosis in histology of the liver. Conversely, a p53 activator, nutlin-3a, decreased the liver injury induced by APAP. In the p53 inhibition models, enhanced sustained JNK activation was seen in the early time course, while the JNK was suppressed with the p53 activator. In conclusion, p53 plays a novel protective role in APAP induced liver injury through inhibiting the activation of JNK, a key mediator in APAP-induced oxidative stress.

Biosynthesis of palladium nanoparticles using Poplar leaf extract and its application in Suzuki coupling reaction

A green route for the synthesis of palladium (Pd) nanoparticles (Pd NPs) employing Poplar leaf extract as a reducing and capping agent is described. The as-prepared Pd NPs are spherical with a face centred cubic structure, a particle distribution of 2.2-6.8 nm and an average particle size of 4.2 nm. The application of this catalyst toward homogeneous Suzuki coupling reactions was investigated. The Pd NPs afforded a yield of 98.86% in the Suzuki coupling reaction of 4-bromotoluene with phenylboronic acid using 0.01 mmol% of the catalyst at 60°C for 30 min under an air atmosphere.

Dithiol disulphide exchange in redox regulation of chloroplast enzymes in response to evolutionary and structural constraints

Redox regulation of chloroplast enzymes via disulphide reduction is believed to control the rates of CO₂ fixation. The study of the thioredoxin reduction pathways and of various target enzymes lead to the following guidelines.

Halogenated flame retardants in bobcats from the midwestern United States

In response to the restrictions of polybrominated diphenyl ether (PBDE) flame retardants in various consumer products, alternative halogenated flame retardants have been subjected to increased use. Compared to aquatic ecosystems, relatively little information is available on the contamination of alternative flame retardants in terrestrial ecosystems, especially with regards to mammalian wildlife. In this study we used a top terrestrial carnivore, the bobcat (Lynx rufus), as a unique biomonitoring species for assessing flame retardant contamination in the Midwestern United States (U.S.) terrestrial ecosystems. Concentrations of ∑PBDEs (including all detectable PBDE congeners) ranged from 8.3 to 1920 ng/g lipid weight (median: 50.3 ng/g lw) in livers from 44 bobcats collected during 2013-2014 in Illinois. Among a variety of alternative flame retardants screened, Dechloranes (including anti- and syn-Dechlorane Plus and Dechlorane-602, 603, and 604), tetrabromo-o-chlorotoluene (TBCT), and hexabromocyclododecane (HBCD) were also frequently detected, with median concentrations of 28.7, 5.2, and 11.8 ng/g lw, respectively. Dechlorane analogue compositions in bobcats were different from what has been reported in other studies, suggesting species- or analogue-dependent bioaccumulation, biomagnification, or metabolism of Dechlorane chemicals in different food webs. Our findings, along with previously reported food web models, suggest Dechloranes may possess substantial bioaccumulation and biomagnification potencies in terrestrial mammalian food webs. Thus, attention should be given to these highly bioavailable flame retardants in future environmental biomonitoring and risk assessments in a post-PBDE era.

Induction of microRNA-17-5p by p53 protects against renal ischemia-reperfusion injury by targeting death receptor 6

Renal ischemia-reperfusion injury is a leading cause of acute kidney injury; the pathogenesis of which remains poorly understood and effective therapies are still lacking. Here we tested whether microRNAs, identified as critical regulators of cell health and disease, are involved in this process. We found that miR-17-5p was significantly up-regulated during renal ischemia-reperfusion injury in mice and during hypoxia in cultured renal tubular cells. In cultured cells, miR-17-5p directly inhibited the expression of death receptor 6 (DR6) and attenuated apoptosis during hypoxia. Blockade of miR-17-5p abolished the suppression of DR6 and facilitated caspase activation and apoptosis. In vivo, an miR-17-5p mimic suppressed DR6 expression and protected against renal ischemia-reperfusion injury. We further verified that miR-17-5p induction during renal ischemia-reperfusion injury was dependent on p53. Inhibition of p53 with pifithrin-α or a dominant-negative mutant led to the repression of miR-17-5p expression under hypoxia in vitro. Moreover, miR-17-5p induction during renal ischemia-reperfusion injury was attenuated in proximal tubule p53 knockout mice, supporting the role of p53 in miR-17-5p induction in vivo. Thus, p53/miR-17-5p/DR6 is a new protective pathway in renal ischemia-reperfusion injury and may be targeted for the prevention and treatment of ischemic acute kidney injury.

The antioxidant transcription factor Nrf2 contributes to the protective effect of mild thermotolerance (40°C) against heat shock-induced apoptosis

The exposure of cells to low doses of stress induces adaptive survival responses that protect cells against subsequent exposure to toxic stress. The ability of cells to resist subsequent toxic stress following exposure to low dose heat stress at 40°C is known as mild thermotolerance. Mild thermotolerance involves increased expression of heat shock proteins and antioxidants, but the initiating factors in this response are not understood. This study aims to understand the role of the Nrf2 antioxidant pathway in acquisition of mild thermotolerance at 40°C, and secondly, whether the Nrf2 pathway could be involved in the protective effect of thermotolerance against heat-shock (42°C)-induced apoptosis. During cell preconditioning at 40°C, protein expression of the Nrf2 transcription factor increased after 15-60min. In addition, levels of the Nrf2 targets MnSOD, catalase, heme oxygenase-1, glutamate cysteine ligase and Hsp70 increased at 40°C. Levels of these Nrf2 targets were enhanced by Nrf2 activator oltipraz and decreased by shRNA targeting Nrf2. Levels of pro-oxidants increased after 30-60min at 40°C. Pro-oxidant levels were decreased by oltipraz and increased by knockdown of Nrf2. Increased Nrf2 expression and catalase activity at 40°C were inhibited by the antioxidant PEG-catalase and by p53 inhibitor pifithrin-α. These results suggest that mild thermotolerance (40°C) increases cellular pro-oxidant levels, which in turn activate Nrf2 and its target genes. Moreover, Nrf2 contributes to the protective effect of thermotolerance against heat-shock (42°C)-induced apoptosis, because Nrf2 activation by oltipraz enhanced thermotolerance, whereas Nrf2 knockdown partly reversed thermotolerance. Improved knowledge about the different protective mechanisms that mild thermotolerance can activate is crucial for the potential use of this adaptive survival response to treat stress-related diseases.

ATP-Dependent C-F Bond Cleavage Allows the Complete Degradation of 4-Fluoroaromatics without Oxygen

Complete biodegradation of the abundant and persistent fluoroaromatics requires enzymatic cleavage of an arylic C-F bond, probably the most stable single bond of a biodegradable organic molecule. While in aerobic microorganisms defluorination of fluoroaromatics is initiated by oxygenases, arylic C-F bond cleavage has never been observed in the absence of oxygen. Here, an oxygen-independent enzymatic aryl fluoride bond cleavage is described during the complete degradation of 4-fluorobenzoate or 4-fluorotoluene to CO2 and HF in the denitrifying Thauera aromatica: the ATP-dependent defluorination of 4-fluorobenzoyl-coenzyme A (4-F-BzCoA) to benzoyl-coenzyme A (BzCoA) and HF, catalyzed by class I BzCoA reductase (BCR). Adaptation to growth with the fluoroaromatics was accomplished by the downregulation of a promiscuous benzoate-CoA ligase and the concomitant upregulation of 4-F-BzCoA-defluorinating/dearomatizing BCR on the transcriptional level. We propose an unprecedented mechanism for reductive arylic C-F bond cleavage via a Birch reduction-like mechanism resulting in a formal nucleophilic aromatic substitution. In the proposed anionic 4-fluorodienoyl-CoA transition state, fluoride elimination to BzCoA is favored over protonation to a fluorinated cyclic dienoyl-CoA.

IMPORTANCE

Organofluorides are produced as pesticides, pharmaceuticals, and other chemicals and comprise approximately one quarter of all organic compounds in the pharmaceutical and agricultural sectors; they are considered a growing class of environmentally relevant persistent pollutants. Especially in the case of fluoroaromatics, biodegradation is hampered by the extreme stability of the arylic C-F bond. In aerobic microorganisms, degradation proceeds via oxygenase-dependent C-F bond cleavage reactions, whereas the enzymes involved in the degradation of fluoroaromatics at anoxic sites are unknown. Here we report a strategy for the complete biodegradation of a fluoroaromatic to CO2 and HF in a denitrifying bacterium via activation to a CoA ester, followed by oxygen-independent arylic C-F bond cleavage catalyzed by an ATP-dependent enzyme. This reaction, in conjunction with a transcriptional adaptation to fluorinated growth substrates, is essential for the anoxic biodegradation of 4-fluorobenzoate/4-F-toluene and probably other fluoroaromatics.

On-board measurements of gaseous pollutant emission characteristics under real driving conditions from light-duty diesel vehicles in Chinese cities

A total of 15 light-duty diesel vehicles (LDDVs) were tested with the goal of understanding the emission factors of real-world vehicles by conducting on-board emission measurements. The emission characteristics of hydrocarbons (HC) and nitrogen oxides (NOx) at different speeds, chemical species profiles and ozone formation potential (OFP) of volatile organic compounds (VOCs) emitted from diesel vehicles with different emission standards were analyzed. The results demonstrated that emission reductions of HC and NOx had been achieved as the control technology became more rigorous from Stage I to Stage IV. It was also found that the HC and NOx emissions and percentage of O2 dropped with the increase of speed, while the percentage of CO2 increased. The abundance of alkanes was significantly higher in diesel vehicle emissions, approximately accounting for 41.1%-45.2%, followed by aromatics and alkenes. The most abundant species were propene, ethane, n-decane, n-undecane, and n-dodecane. The maximum incremental reactivity (MIR) method was adopted to evaluate the contributions of individual VOCs to OFP. The results indicated that the largest contributors to O3 production were alkenes and aromatics, which accounted for 87.7%-91.5%. Propene, ethene, 1,2,4-trimethylbenzene, 1-butene, and 1,2,3-trimethylbenzene were the top five VOC species based on their OFP, and accounted for 54.0%-64.8% of the total OFP. The threshold dilution factor was applied to analyze the possibility of VOC stench pollution. The majority of stench components emitted from vehicle exhaust were aromatics, especially p-diethylbenzene, propylbenzene, m-ethyltoluene, and p-ethyltoluene.

Concentrations and distributions of polybrominated diphenyl ethers and novel brominated flame retardants in tree bark and human hair from Yunnan Province, China

The concentrations and distributions of polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (NBFRs) in tree bark and hair samples from the same area in Yunnan Province, China, were determined. The total PBDE and NBFR concentrations in the tree bark samples were 3.8 ng/g lipid weight to 91 ng/g lipid weight and 0.23 ng/g lipid weight to 5.0 ng/g lipid weight, respectively. The total PBDE and NBFR concentrations in the hair samples were 2.1 ng/g dry weight to 14 ng/g dry weight and 0.083 ng/g dry weight to 0.29 ng/g dry weight, respectively. Decabromodiphenyl ether had similar distributions in the tree bark and hair samples, but other PBDE congeners and NBFRs had different distributions in the tree bark and hair samples. External exposure was found to be mainly responsible for the total PBDE and pentabromotoluene concentrations in hair, but both external and internal exposure were responsible for the pentabromophenyl and hexabromobenzene concentrations in hair.

Statewide surveillance of halogenated flame retardants in fish in Illinois, USA

In order to better understand the exposure of aquatic systems to halogenated flame retardant contaminants, the present study investigated a variety of legacy and emerging flame retardants in common carp and largemouth bass collected from 58 stations across Illinois (United States). The data revealed that polybrominated diphenyl ethers (PBDEs) generally dominated the flame retardant residues in Illinois fish. Concentrations of ΣPBDEs (including all detectable PBDE congeners) ranged from 24.7 to 8270 ng/g lipid weight (median: 135 ng/g lw) in common carp and 15-3870 ng/g lw (median: 360 ng/g lw) in largemouth bass. In addition to PBDEs, Dechlorane analogues (i.e. Dec-603, Dec-604, and Chlordane Plus) were also frequently detected. Median concentrations of ΣDechloranes (including all detected Dechlorane analogues) were 34.4 and 23.3 ng/g lw in common carp and largemouth bass, respectively. Other emerging flame retardants, including tetrabromo-o-chlorotoluene (TBCT), hexabromobenzene (HBBZ), 2-ethylhexyltetrabromobenzoate (EH-TBB), and bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (BEH-TEBP), were also detected in 40-78% of the fish at the monitored stations. Spatial analysis revealed significantly greater PBDE concentrations in fish living in impaired urban streams and lakes compared to those from the impaired agricultural and unimpaired agricultural/urban waters, demonstrating a significant urban influence on PBDE contamination. Future studies and environmental monitoring are recommended to focus on temporal trends of PBDEs and alternative flame retardants, as well as human exposure risks via edible fishes, in the identified Areas of Concern within Illinois.

Polybrominated diphenyl ethers (PBDEs) and alternative brominated flame retardants (aBFRs) in sediments from four bays of the Yellow Sea, North China

The distribution characteristics and potential sources of polybrominated diphenyl ethers (PBDEs) and alternative brominated flame retardants (aBFRs) were investigated in 54 surface sediment samples from four bays (Taozi Bay, Sishili Bay, Dalian Bay, and Jiaozhou Bay) of North China's Yellow Sea. Of the 54 samples studied, 51 were collected from within the four bays and 3 were from rivers emptying into Jiaozhou Bay. Decabromodiphenylethane (DBDPE) was the predominant flame retardant found, and concentration ranged from 0.16 to 39.7 ng g(-1) dw and 1.13-49.9 ng g(-1) dw in coastal and riverine sediments, respectively; these levels were followed by those of BDE 209, and its concentrations ranged from n.d. to 10.2 ng g(-1) dw and 0.05-7.82 ng g(-1) dw in coastal and riverine sediments, respectively. The levels of DBDPE exceeded those of decabromodiphenyl ether (BDE 209) in most of the samples in the study region, whereas the ratio of DBDPE/BDE 209 varied among the four bays. This is indicative of different usage patterns of brominated flame retardants (BFRs) and also different hydrodynamic conditions among these bay areas. The spatial distribution and composition profile analysis indicated that BFRs in Jiaozhou Bay and Dalian Bay were mainly from local sources, whereas transport from Laizhou Bay by coastal currents was the major source of BFRs in Taozi Bay and Sishili Bay. Both the ∑PBDEs and ∑aBFRs (sum of pentabromotoluene (PBT), 2,3-diphenylpropyl-2,4,6-tribromophenyl ether (DPTE), pentabromoethylbenzene (PBEB), and hexabromobenzene (HBB)) were at low concentrations in all the sediments. This is probably attributable to a combination of factors such as low regional usage of these products, atmospheric deposition patterns, coastal currents transportation patterns, and degradation processes for higher BDE congeners. This paper is the first study that has investigated the levels of DBDPE in the coastal sediments of China's Yellow Sea.

Anesthetic Isoflurane Induces DNA Damage Through Oxidative Stress and p53 Pathway

DNA damage is associated with aging and neurological disorders, including Alzheimer's disease. Isoflurane is a commonly used anesthetic. It remains largely unknown whether isoflurane induces DNA damage. Phosphorylation of the histone protein H2A variant X at Ser139 (γH2A.X) is a marker of DNA damage. We therefore set out to assess the effects of isoflurane on γH2A.X level in H4 human neuroglioma cells and in brain tissues of mice. Oxidative stress, caspase-activated DNase (CAD), and the p53 signaling pathway are involved in DNA damage. Thus, we determined the interaction of isoflurane with reactive oxygen species (ROS), CAD, and p53 to illustrate the underlying mechanisms. The cells were treated with 2 % isoflurane for 3 or 6 h. The mice were anesthetized with 1.4 % isoflurane for 2 h. Western blot, immunostaining and live cell fluorescence staining were used in the experiments. We showed that isoflurane increased levels of γH2A.X, cleaved caspase-3, and nucleus translocation of CAD and decreased levels of inhibitor of CAD (ICAD) and p53. Isoflurane enhanced the nucleus level of γH2A.X. Moreover, caspase inhibitor Z-VAD and ROS generation inhibitor N-acetyl-L-cysteine (NAC) attenuated the isoflurane-induced increase in γH2A.X level. However, NAC did not significantly alter the isoflurane-induced reduction in p53 level. Finally, p53 activator (actinomycin D) and inhibitor (pifithrin-α) attenuated and potentiated the isoflurane-induced increase in γH2A.X level, respectively. These findings suggest that isoflurane might induce DNA damage, as represented by increased γH2A.X level, via induction of oxidative stress and inhibition of the repair of DNA damage through the p53 signaling pathway.

Preclinical effects of honokiol on treating glioblastoma multiforme via G1 phase arrest and cell apoptosis

BACKGROUND

Our previous study showed that honokiol, a bioactive polyphenol, can traverse the blood-brain barrier and kills neuroblastoma cells.

PURPOSE

In this study, we further evaluated the preclinical effects of honokiol on development of malignant glioma and the possible mechanisms.

METHODS

Effects of honokiol on viability, caspase activities, apoptosis, and cell cycle arrest in human glioma U87 MG or U373MG cells were assayed. As to the mechanisms, levels of inactive or phosphorylated (p) p53, p21, CDK6, CDK4, cyclin D1, and E2F1 were immunodetected. Pifithrin-α (PFN-α), a p53 inhibitor, was pretreated into the cells. Finally, our in vitro findings were confirmed using intracranial nude mice implanted with U87 MG cells.

RESULTS

Exposure of human U87 MG glioma cells to honokiol decreased the cell viability. In parallel, honokiol induced activations of caspase-8, -9, and -3, apoptosis, and G1 cell cycle arrest. Treatment of U87 MG cells with honokiol increased p53 phosphorylation and p21 levels. Honokiol provoked signal-transducing downregulation of CDK6, CDK4, cyclin D1, phosphorylated (p)RB, and E2F1. Pretreatment of U87 MG cells with PFN-α significantly reversed honokiol-induced p53 phosphorylation and p21 augmentation. Honokiol-induced alterations in levels of CDK6, CDK4, cyclin D1, p-RB, and E2F1 were attenuated by PFN-α. Furthermore, honokiol could induce apoptotic insults to human U373MG glioma cells. In our in vivo model, administration of honokiol prolonged the survival rate of nude mice implanted with U87 MG cells and induced caspase-3 activation and chronological changes in p53, p21, CDK6, CDK4, cyclin D1, p-RB, and E2F1.

CONCLUSIONS

Honokiol can repress human glioma growth by inducing apoptosis and cell cycle arrest in tumor cells though activating a p53/cyclin D1/CDK6/CDK4/E2F1-dependent pathway. Our results suggest the potential of honokiol in therapies for human malignant gliomas.