[en] Misonidazole, a hypoxic cell radiosensitizer, can produce peripheral sensory disorders in humans. It has been studied in monkeys with a computer-controlled system for evaluating vibration sensitivity. Monkeys were trained to report when vibration was stimulating the finger tip. Sinusoidal vibrations of several frequencies were presented. Two monkeys were dosed with misonidazole and their vibration sensitivity tested. They received a dose of 3 g/m² (about 180 mg/kg) twice weekly over a period of 6 to 10 weeks. An amplitude-frequency detection function was determined for each monkey before and after drug treatment. An analysis of covariance comparing polynomial regressions was performed. A significant difference (p < 0.001) was found between control and experimental curves in both monkeys. Pharmacokinetic data indicated a half-life of the drug in blood of about 4 to 5 hr. The overall half-life for elimination did not increase throughout prolonged treatment with msonidazole. Neither motor nor sensory nerve conduction velocity was reduced after treatment

[en] Single doses of lead (trace to 445 mg/kg) were administered per os to suckling and adult mice. Both groups exhibited dose-independent lead retention when doses of 4 to 445 mg/kg were administered. However, developmental differences in the fraction of initial dose (FID) retained were evident for all doses administered. A much larger FID was retained in both age groups following administration of carrier-free ²⁰³Pb. The results are consistent with a mechanism of gastrointestinal lead absorption comprising two or more processes. Developmental differences were also observed in organ lead concentration relative to whole body concentration for kidneys, skull and brain 6 days following lead administration. Lead retentions (relative to whole body retention) in brain and in bone were linearly related to dose of lead administered in both suckling and adult age groups. Though uptake of lead into brain and into femur was observed to be directly related to dose over a wide range, relative blood lead concentrations were not linearly correlated with dose administered. The relationships between lead concentrations of blood and organ(s) were also shown to be nonlinear relative to dose. However, blood lead concentration was found to be a reliable indicator of kidney and liver lead concentrations following an acute lead exposure

[en] Highlights: • Abnormal dose-response is present in compounds tested in AR HTS agonism assay. • NMDR compounds vary by chemical class, bioactivity profile, dose-response curve. • Cytotoxicity, luciferase inhibition interfere with dose-response examination. Modern High-Throughput Screening (HTS) techniques allow to determine in vitro bioactivity of tens of thousands of chemicals within a relatively short period of time and tested compounds are usually interpreted as either active or inactive. The interpretation is mostly based on the assumption of monotonic dose-response. This approach ignores potential abnormal dose-response relationships, such as non-monotonic dose-response (NMDR). NMDR presents a serious challenge to toxicologists and pharmacologists, since they undermine the usefulness of such concepts as lowest-observed-adverse-effect level (LOAEL) and no-observed-adverse-effect level (NOAEL). The possible presence of the NMDR in Androgen receptor (AR) agonism was examined for a structurally diverse set of chemicals (~8 300 unique compounds) from Tox21 project library. The source of activity data is Tox21 AR agonism luciferase-based HTS on the MDA-MB-453 cell line. The examination of curve fitting for 35,328 dose-response data entries was based on modified version of existing criteria for determination of NMDR. The bias that arises from compounds' cytotoxicity and interference with firefly luciferase protein was also studied. The examination has shown evidence of NMDR for several compounds, including known AR antagonists (e. g. Cyproterone acetate) and other known endocrine disruptors (e. g. Tranilast). Compounds were divided into 3 groups based on chemical class, known biological activity profile and the shape of dose-response curve. The challenges of using HTS data to determine NMDR and benefits of this analysis are discussed

[en] Highlights: • Network pharmacology was used to explore the antitumor mechanism of cinobufagin. • EGFR and CDK2 were the key targets involved in antitumor effects of cinobufagin. • Cinobufagin inhibited growth of tumor cells by abrogating EGFR-CDK2 signaling. Hepatocellular carcinoma (HCC) is one of the deadliest cancers with high mortality and poor prognosis, and the investigation on new approaches and effective drugs for HCC therapy is of great significance. In our study, we demonstrate that treatment with cinobufagin, a natural compound isolated from traditional chinese medicine Chansu, reduces proliferation and the colony formation capacity of the human hepatoma cells in vitro, in addition, cinobufagin induces mitotic arrest in human hepatoma cells. The results of a network pharmacology-based analysis show that EGFR, MAPK1, PTK2, CDK2, MAPK3, ESR1, CDK1, PRKCA, AR, and CSNK2A1 are the key targets involved in the anti-tumor activities of cinobufagin, additionally, several signaling pathways such as proteoglycans in cancer, pathways in cancer, HIF-1 signaling pathway, VEGF signaling pathway, ErbB signaling pathway, and PI3K-AKT signaling pathway are identified as the potential pathways involved in the inhibitory effects of cinobufagin against HCC. Furthermore, at the molecular level, we find that cinobufagin decreases EGFR expression and CDK2 activity in human hepatoma cells. Inhibition of EGFR or CDK2 expression could not only suppress the growth of tumor cells but also enhance the inhibitory effects of cinobufagin on the proliferative potential of human hepatoma cells. We also demonstrate that EGFR positively regulates CDK2 expression. Furthermore, EGFR inhibitor gefitinib or CDK2 inhibitor CVT-313 synergistically enhances anticancer effects of cinobufagin in human hepatoma cells. Taken together, these findings indicate that cinobufagin may exert antitumor effects by suppressing EGFR-CDK2 signaling, and our study suggests that cinobufagin may be a novel, promising anticancer agent for the treatment of HCC.

[en] Highlights: • Exposure of silver nanocolloids (SNC) induced serious deformities during medaka embryogenesis. • 5 glycan-related genes including human glycosylation diseases were employed. • SNC exposure changed the gene expressions and N-glycan syntheses in medaka. • The gene expressions were significant in the brain and essential for embryogenesis. • SNC may inhibit the skeletal formation of the head and eye through gene expression. Silver nanomaterials such as silver nanocolloids (SNC) contribute to environmental pollution and have adverse ecological effects on aquatic organisms. In particular, chemical exposure of fish during embryogenesis leads to deformities and puts the population at risk. Although glycans and glycosylation are known to be important for proper morphology in embryogenesis, little glycobiology-based research has examined morphological disorders caused by environmental pollutants. This study addressed the glycobiological effects of SNC exposure on medaka embryogenesis. After exposure of medaka embryos to SNC, deformities such as small heads and deformed eyes were observed. The expression of five glycan-related genes (alg2, gnsb, b4galt2, b3gat1a, and b3gat2) was significantly altered, with changes depending on the embryonic stage at exposure, with more severe deformities with exposure at earlier stages. In situ hybridization analyses indicated that the five genes were expressed mainly in the head region; exposure of SNC suppressed alg2 and gnsb and enhanced b4galt2 and b3gat1a expression relative to controls on day 7. Loss (siRNA)- and gain (RNA overexpression)-of-function experiments confirmed that alg2, gnsb, and b4galt2 are essential for embryogenesis. The effects of SNC exposure on glycan synthesis were estimated by glycan structure analysis. In the medaka embryo, high mannose–type glycans were dominant, and SNC exposure altered glycan synthesis. The alteration was more significant when exposure occurred at an early stage of medaka embryogenesis. Thus, SNC exposure causes embryonic deformities in medaka embryos through disordered glycosylation.

[en] Highlights: • A variety of reference drugs linked to seizures were studied in 2 in vitro assays. • Hippocampal slice and neuron-based microelectrode array assays were compared. • In vitro assays can help predict seizure liability in preclinical risk assessment. • Prediction and throughput of microelectrode array can be refined by more validation. An effective in vitro screening assay to detect seizure liability in preclinical development can contribute to better lead molecule optimization prior to candidate selection, providing higher throughput and overcoming potential brain exposure limitations in animal studies. This study explored effects of 26 positive and 14 negative reference pharmacological agents acting through different mechanisms, including 18 reference agents acting on glutamate signaling pathways, in a brain slice assay (BSA) of adult rat to define the assay's sensitivity, specificity, and limitations. Evoked population spikes (PS) were recorded from CA1 pyramidal neurons of hippocampus (HPC) in the BSA. Endpoints for analysis were PS area and PS number. Most positive references (24/26) elicited a concentration-dependent increase in PS area and/or PS number. The negative references (14/14) had little effect on the PS. Moreover, we studied the effects of 15 reference agents testing positive in the BSA on spontaneous activity in E18 rat HPC neurons monitored with microelectrode arrays (MEA), and compared these effects to the BSA results. From these in vitro studies we conclude that the BSA provides 93% sensitivity and 100% specificity in prediction of drug-induced seizure liability, including detecting seizurogenicity by 3 groups of metabotropic glutamate receptor (mGluR) ligands. The MEA results seemed more variable, both quantitatively and directionally, particularly for endpoints capturing synchronized electrical activity. We discuss these results from the two models, comparing each with published results, and provide potential explanations for differences and future directions.

[en] Highlights: • TC-I-15 inhibits the collagen-binding integrin, α2β1, with IC₅₀ < 30 μM on GFOGER. • Inhibition seems competitive with high potency, IC₅₀ < 1 μM, on low-affinity GLOGEN. • TC-I-15 inhibits α1β1 with similar potency, α11β1 weakly, but not α10β1. • The KTS disintegrin, obtustatin, is specific for α1β1. • Both inhibitors act on integrins in situ, not on isolated α-subunit I-domains. Integrins are a family of 24 adhesion receptors which are both widely-expressed and important in many pathophysiological cellular processes, from embryonic development to cancer metastasis. Hence, integrin inhibitors are valuable research tools which may have promising therapeutic uses. Here, we focus on the four collagen-binding integrins α1β1, α2β1, α10β1 and α11β1. TC-I-15 is a small molecule inhibitor of α2β1 that inhibits platelet adhesion to collagen and thrombus deposition, and obtustatin is an α1β1-specific disintegrin that inhibits angiogenesis. Both inhibitors were applied in cellular adhesion studies, using synthetic collagen peptide coatings with selective affinity for the different collagen-binding integrins and testing the adhesion of C2C12 cells transfected with each. Obtustatin was found to be specific for α1β1, as described, whereas TC-I-15 is shown to be non-specific, since it inhibits both α1β1 and α11β1 as well as α2β1. TC-I-15 was 100-fold more potent against α2β1 binding to a lower-affinity collagen peptide, suggestive of a competitive mechanism. These results caution against the use of integrin inhibitors in a therapeutic or research setting without testing for cross-reactivity.

[en] Highlights: • Deltamethrin enhances slow inactivation of Nav1.7, Nav1.8 and Nav1.9. • Nav1.9 persistent and tail currents are enhanced by deltamethrin. • Deltamethrin modifies Nav1.8 use-dependently only at depolarized holding potentials. The insecticide deltamethrin of the pyrethroid class mainly targets voltage-gated sodium channels (Navs). Deltamethrin prolongs the opening of Navs by slowing down fast inactivation and deactivation. Pyrethroids are supposedly safe for humans, however, they have also been linked to the gulf-war syndrome, a neuropathic pain condition that can develop following exposure to certain chemicals. Inherited neuropathic pain conditions have been linked to mutations in the Nav subtypes Nav1.7, Nav1.8, and Nav1.9. Here, we examined the effect of deltamethrin on the human isoforms Nav1.7, Nav1.8, and Nav1.9_C4 (chimera containing the C-terminus of rat Nav1.4) heterologously expressed in HEK293T and ND7/23 cells using whole-cell patch-clamp electrophysiology. For all three Nav subtypes, we observed increased persistent and tail currents that are typical for Nav channels modified by deltamethrin. The most surprising finding was an enhanced slow inactivation induced by deltamethrin in all three Nav subtypes. An enhanced slow inactivation is contrary to the prolonged opening caused by pyrethroids and has not been described for deltamethrin or any other pyrethroid before. Furthermore, we found that the fraction of deltamethrin-modified channels increased use-dependently. However, for Nav1.8, the use-dependent potentiation occurred only when the holding potential was increased to −90 mV, a potential at which the tail currents decay more slowly. This indicates that use-dependent modification is due to an accumulation of tail currents. In summary, our findings support a novel mechanism whereby deltamethrin enhances slow inactivation of voltage-gated sodium channels, which may, depending on the cellular resting membrane potential, reduce neuronal excitability and counteract the well-described pyrethroid effects of prolonging channel opening.

[en] Highlights: • Benzo(a)pyrene exposure in utero upregulated SNCA mRNA transcription. • Benzo(a)pyrene exposure in utero injured protein degradation system. • Benzo(a)pyrene exposure in utero promoted α-syn accumulation and aggregation. • Benzo(a)pyrene exposure induced microglial activation and neuroinflammation. • Benzo(a)pyrene exposure induced dopaminergic neuronal loss in the substantia nigra. Previous work indicated that benzo[a]pyrene (B(a)P) exposure in utero might adversely affect neurodevelopment and cause Parkinson's Disease (PD)-like symptoms. However, the effect of utero exposure to B(a)P on PD-like α-synucleinopathy and the mechanism under are unclear.

[en] Highlights: • Inhaled benzene exposure increases the levels of blood endothelial microparticles. • In vitro, benzene metabolite trans, trans-mucondialdehyde induces endothelial cell apoptosis and microparticles formation. • Inhaled benzene exposure decreases the levels of hematopoietic progenitor cells in the bone marrow. • Inhaled benzene exposure augments the circulating levels of platelet-leukocyte adducts. Benzene is a ubiquitous environmental pollutant. Recent population-based studies suggest that benzene exposure is associated with an increased risk for cardiovascular disease. However, it is unclear whether benzene exposure by itself is sufficient to induce cardiovascular toxicity. We examined the effects of benzene inhalation (50 ppm, 6 h/day, 5 days/week, 6 weeks) or HEPA-filtered air exposure on the biomarkers of cardiovascular toxicity in male C57BL/6J mice. Benzene inhalation significantly increased the biomarkers of endothelial activation and injury including endothelial microparticles, activated endothelial microparticles, endothelial progenitor cell microparticles, lung endothelial microparticles, and activated lung and endothelial microparticles while having no effect on circulating levels of endothelial adhesion molecules, endothelial selectins, and biomarkers of angiogenesis. To understand how benzene may induce endothelial injury, we exposed human aortic endothelial cells to benzene metabolites. Of the metabolites tested, trans,trans-mucondialdehyde (10 μM, 18h) was the most toxic. It induced caspases-3, -7 and -9 (intrinsic pathway) activation and enhanced microparticle formation by 2.4-fold. Levels of platelet-leukocyte aggregates, platelet macroparticles, and a proportion of CD4⁺ and CD8⁺ T-cells were also significantly elevated in the blood of the benzene-exposed mice. We also found that benzene exposure increased the transcription of genes associated with endothelial cell and platelet activation in the liver; and induced inflammatory genes and suppressed cytochrome P450s in the lungs and the liver. Together, these data suggest that benzene exposure induces endothelial injury, enhances platelet activation and inflammatory processes; and circulatory levels of endothelial cell and platelet-derived microparticles and platelet-leukocyte aggregates are excellent biomarkers of cardiovascular toxicity of benzene.