CSF1R antagonism results in increased supraspinal infiltration in EAE.

BACKGROUND: Colony stimulating factor 1 receptor (CSF1R) signaling is crucial for the maintenance and function of various myeloid subsets. CSF1R antagonism was previously shown to mitigate clinical severity in experimental autoimmune encephalomyelitis (EAE). The associated mechanisms are still not well delineated. METHODS: To assess the effect of CSF1R signaling, we employed the CSF1R antagonist PLX5622 formulated in chow (PLX5622 diet, PD) and its control chow (control diet, CD). We examined the effect of PD in steady state and EAE by analyzing cells isolated from peripheral immune organs and from the CNS via flow cytometry. We determined CNS infiltration sites and assessed the extent of demyelination using immunohistochemistry of cerebella and spinal cords. Transcripts of genes associated with neuroinflammation were also analyzed in these tissues. RESULTS: In addition to microglial depletion, PD treatment reduced dendritic cells and macrophages in peripheral immune organs, both during steady state and during EAE. Furthermore, CSF1R antagonism modulated numbers and relative frequencies of T effector cells both in the periphery and in the CNS during the early stages of the disease. Classical neurological symptoms were milder in PD compared to CD mice. Interestingly, a subset of PD mice developed atypical EAE symptoms. Unlike previous studies, we observed that the CNS of PD mice was infiltrated by increased numbers of peripheral immune cells compared to that of CD mice. Immunohistochemical analysis showed that CNS infiltrates in PD mice were mainly localized in the cerebellum while in CD mice infiltrates were primarily localized in the spinal cords during the onset of neurological deficits. Accordingly, during the same timepoint, cerebella of PD but not of CD mice had extensive demyelinating lesions, while spinal cords of CD but not of PD mice were heavily demyelinated. CONCLUSIONS: Our findings suggest that CSF1R activity modulates the cellular composition of immune cells both in the periphery and within the CNS, and affects lesion localization during the early EAE stages.

Impact of zinc supplementation on phenotypic antimicrobial resistance of fecal commensal bacteria from pre-weaned dairy calves.

The objective of this study was to evaluate the impact of dietary zinc supplementation in pre-weaned dairy calves on the phenotypic antimicrobial resistance (AMR) of fecal commensal bacteria. A repository of fecal specimens from a random sample of calves block-randomized into placebo (n = 39) and zinc sulfate (n = 28) groups collected over a zinc supplementation clinical trial at the onset of calf diarrhea, calf diarrheal cure, and the last day of 14 cumulative days of zinc or placebo treatment were analyzed. Antimicrobial susceptibility testing was conducted for Enterococcus spp. (n = 167) and E. coli (n = 44), with one representative isolate of each commensal bacteria tested per sample. Parametric survival interval regression models were constructed to evaluate the association between zinc treatment and phenotypic AMR, with exponentiated accelerated failure time (AFT) coefficients adapted for MIC instead of time representing the degree of change in AMR (MIC Ratio, MR). Findings from our study indicated that zinc supplementation did not significantly alter the MIC in Enterococcus spp. for 13 drugs: gentamicin, vancomycin, ciprofloxacin, erythromycin, penicillin, nitrofurantoin, linezolid, quinupristin/dalfopristin, tylosin tartrate, streptomycin, daptomycin, chloramphenicol, and tigecycline (MR = 0.96-2.94, p > 0.05). In E. coli, zinc supplementation was not associated with resistance to azithromycin (MR = 0.80, p > 0.05) and ceftriaxone (MR = 0.95, p > 0.05). However, a significant reduction in E. coli MIC values was observed for ciprofloxacin (MR = 0.17, 95% CI 0.03-0.97) and nalidixic acid (MR = 0.28, 95% CI 0.15-0.53) for zinc-treated compared to placebo-treated calves. Alongside predictions of MIC values generated from these 17 AFT models, findings from this study corroborate the influence of age and antimicrobial exposure on phenotypic AMR.

Temporal development of arsenic speciation and extractability in acidified and non-acidified paddy soil amended with silicon-rich fly ash and manganese- or zinc-oxides under flooded and drainage conditions.

Oxides of silicon (Si), manganese (Mn), and zinc (Zn) have been used as soil amendments to reduce As mobility and uptake in paddy soil systems. However, these amendments are hypothesized to be affected differently depending on the soil pH and their effect on As speciation in rice paddy systems is not fully understood. Herein, we used a microcosm experiment to investigate the effects of natural Si-rich fly ash and synthetic Mn and Zn oxides on the temporal development of porewater chemistry, including aqueous As speciation (As(III), As(V), MMA, DMA, and DMMTA) and solid-phase As solubility, in a naturally calcareous soil with or without soil acidification (with sulfuric acid) during 28 days of flooding and subsequent 14 days of drainage. We found that soil acidification to pH 4.5 considerably increased the solubility of Si, Fe, Mn, and Zn compared to the non-acidified soil. Additions of Mn and Zn oxides decreased the concentrations of dissolved arsenite and arsenate in the non-acidified soil whereas additions of Zn oxide and combined Si-Zn oxides increased them in the acidified soil. The Si-rich fly ash did not increase dissolved Si and As in the acidified and non-acidified soils. Dimethylated monothioarsenate (DMMTA) was mainly observed in the acidified soil during the later stage of soil flooding. The initial 28 days of soil flooding decreased the levels of soluble and exchangeable As and increased As associated with Mn oxides, whereas the subsequent 14 days of soil drainage reversed the trend. This study highlighted that soil acidification considerably controlled the solubilization of Ca and Fe, thus influencing the soil pH-Eh buffering capacity, the solubility of Si, Mn, and Zn oxides, and the mobility of different As species in carbonate-rich and acidic soils under redox fluctuations.

Biocompatible and biodegradable Bletilla striata polysaccharides hydrogels crosslinked by BDDE for wound healing through the regulating of macrophage polarization.

Bletilla striata polysaccharide (BSP) is a naturally occurring polysaccharide that demonstrates notable biocompatibility and biodegradability. Additionally, BSP possesses therapeutic attributes, including anti-inflammatory and reparative actions. Herein, we report a novel BSP hydrogel prepared using 1,4-butanediol diglycidyl ether (BDDE) as a cross-linking agent. The hydrogel was synthesized via condensation of the hydroxyl group in the BSP molecule with the epoxy group in BDDE. This technique of preparation preserves BSP's natural properties while avoiding any potentially hazardous or adverse effects that may occur during the chemical alteration. Compared with BSP before crosslinking, BSP hydrogel has distinct advantages, such as a three-dimensional network structure, improved water retention, enhanced swelling capacity, greater thermal stability, and superior mechanical properties. Experiments on in vitro cytotoxicity, hemolysis, and degradation revealed that BSP hydrogel had good biocompatibility and biodegradability. Finally, we evaluated the in vivo wound repair effect of BSP hydrogel, and the results showed that BSP hydrogel had a significant wound-healing effect. Furthermore, the BSP hydrogel promoted the polarization of M1-type macrophages towards the M2-type and reduced the inflammatory response during the wound healing phase. Because of its ease of production, safety, efficacy, and environmental friendliness, BSP hydrogel is considered a highly promising material for wound dressings.

Saltiness Enhancement through the Synergism of Pyroglutamyl Peptides and Organic Acids.

Excess sodium intake poses health risks, prompting the exploration of taste modulators to reduce the salt content in low-sodium foods yet maintain salty perception. Previous research found a subthreshold synergistic effect among pyroglutamyl dipeptides on saltiness enhancement. This study investigated the subthreshold synergistic effect of pyroglutamyl peptides and organic acids on saltiness perception. Pyroglutamyl dipeptides (pgluE, pgluV), pyroglutamyl tripeptides (pgluVL and pgluVC), and organic acids (malic acid and succinic acid) were explored in a model system and subsequently in commercial brown onion sauce. The detection thresholds of peptides (pgluE, pgluV, pgluVL, and pgluVC) were determined to be 646, 77, 273, and 221 µmol/L, respectively, and the subthreshold synergistic effect of the pyroglutamyl tripeptides and organic acids was determined using the isobologram method. One of the eight combinations of pyroglutamyl tripeptides with pyroglutamyl dipeptide (pgluV) showed a subthreshold synergistic effect, whereas four combinations of tripeptides with malic acid and one combination with succinic acid exhibited a subthreshold synergistic effect. In commercial brown onion sauce, 25 and 30% salt reductions were achieved using the combinations of the tripeptides with malic acid and succinic acid, respectively. This research lays the foundation for future investigations into the potential combinations of pyroglutamyl peptides and organic acids for saltiness enhancement in low-sodium foods.

Studying Fluorescence Sensing of Acetone and Tryptophan and Antibacterial Properties Based on Zinc-Based Triple Interpenetrating Metal-Organic Skeletons.

Two triple interpenetrating Zn(II)-based MOFs were studied in this paper. Named [Zn6(1,4-bpeb)4(IPA)6(H2O)]n (MOF-1) and {[Zn3(1,4-bpeb)1.5(DDBA)3]n·2DMF} (MOF-2), {1,4-bpeb = 1,4-bis [2-(4-pyridy1) ethenyl]benze, IPA = Isophthalic acid, DDBA = 3,3'-Azodibenzoic acid}, they were synthesized by the hydrothermal method and were characterized and stability tested. The results showed that MOF-1 had good acid-base stability and solvent stability. Furthermore, MOF-1 had excellent green fluorescence and with different phenomena in different solvents, which was almost completely quenched in acetone. Based on this phenomenon, an acetone sensing test was carried out, where the detection limit of acetone was calculated to be 0.00365% (volume ratio). Excitingly, the MOF-1 could also be used as a proportional fluorescent probe to specifically detect tryptophan, with a calculated detection limit of 34.84 µM. Furthermore, the mechanism was explained through energy transfer and competitive absorption (fluorescence resonance energy transfer (FRET)) and internal filtration effect (IFE). For antibacterial purposes, the minimum inhibitory concentrations of MOF-1 against Escherichia coli and Staphylococcus aureus were 19.52 µg/mL and 39.06 µg/mL, respectively, and the minimum inhibitory concentrations of MOF-2 against Escherichia coli and Staphylococcus aureus were 68.36 µg/mL and 136.72 µg/mL, respectively.

Changes in Temperature Alter the Toxicity of Polycyclic Aromatic Compounds to American Lobster (Homarus americanus) Larvae.

Polycyclic aromatic compounds (PACs) present in the water column are considered to be one of the primary contaminant groups contributing to the toxicity of a crude oil spill. Because crude oil is a complex mixture composed of thousands of different compounds, oil spill models rely on quantitative structure-activity relationships like the target lipid model to predict the effects of crude oil exposure on aquatic life. These models rely on input provided by single species toxicity studies, which remain insufficient. Although the toxicity of select PACs has been well studied, there is little data available for many, including transformation products such as oxidized hydrocarbons. In addition, the effect of environmental influencing factors such as temperature on PAC toxicity is a wide data gap. In response to these needs, in the present study, Stage I lobster larvae were exposed to six different understudied PACs (naphthalene, fluorenone, methylnaphthalene, phenanthrene, dibenzothiophene, and fluoranthene) at three different relevant temperatures (10, 15, and 20 °C) all within the biological norms for the species during summer when larval releases occur. Lobster larvae were assessed for immobilization as a sublethal effect and mortality following 3, 6, 12, 24, and 48 h of exposure. Higher temperatures increased the rate at which immobilization and mortality were observed for each of the compounds tested and also altered the predicted critical target lipid body burden, incipient median lethal concentration, and elimination rate. Our results demonstrate that temperature has an important influence on PAC toxicity for this species and provides critical data for oil spill modeling. More studies are needed so oil spill models can be appropriately calibrated and to improve their predictive ability. Environ Toxicol Chem 2023;42:2389-2399. © 2023 SETAC.

Curcumin-zinc framework encapsulated microneedle patch for promoting hair growth.

Hair loss is a growing esthetic condition driven by complex mechanisms that has numerous psycho-social implications. Conventional drug applications usually focus on a single treatment target, and the penetration depth restricts the post-delivery effect. Method: We fabricated a curcumin-zinc framework (ZnMOF) encapsulated gamma-polyglutamic acid (γ-PGA) microneedle patch (ZnMOF-MN) as a multifunctional biosafe transdermal drug delivery system. ZnMOF was characterized with the field emission scanning electron microscope (FE-SEM), dynamic light scattering (DLS), elemental mapping, and X-ray diffraction (XRD). The topographical and hygroscopic features of ZnMOF-MN were characterized with SEM. The in vitro ZnMOF release profile and the in vivo penetration of ZnMOF-MN were also evaluated. The anti-oxidant, anti-apoptosis, and antiandrogen effects of ZnMOF solution and ZnMOF-MN extract were studied on mouse dermal papilla cells (DPCs). Two animal models (in C57BL/6 mice), including androgenic alopecia (AGA) model and wound healing model, were used to identify the therapeutic effect of ZnMOF-MN on hair regrowth and wound healing in vivo. Hair follicles, surrounding vessels (CD31+), and proliferating cells (Ki67+) were evaluated by histological staining. Results: ZnMOF crystals were cone-shaped nanoparticles with a size distribution of 424.9 ± 59.01 nm. ZnMOF-MN patch can create temporary holes in the skin to directly and evenly deliver bioactive ZnMOF particles to the targeted depth and achieve a steady and sustained release of Zn2+ and curcumin. In vitro, ZnMOF significantly improved the viability of DPCs against the excess reactive oxygen species (ROS) and inhibited the apoptosis induced by zinc deficiency. In addition, it also reversed the inhibitory effects of dihydrotestosterone (DHT) infiltration. Moreover, the ZnMOF-MN treatment has been proved to accelerate wound healing and increase hair follicles in wound healing models, and improved the hair regrowth in AGA animal models. Enhanced capillary density and cell proliferation observed in the CD31+ and Ki67+ staining of ZnMOF-MN group in both animal models also suggested that ZnMOF can facilitate angiogenesis and promote cell proliferation in the skin, respectively. Conclusion: The ZnMOF-MN treatment is a comprehensive solution with excellent therapeutic efficacy and patient-friendly features for promoting hair growth under various clinical conditions.

Early postnatal microglial ablation in the Ccdc39 mouse model reveals adverse effects on brain development and in neonatal hydrocephalus.

BACKGROUND: Neonatal hydrocephalus is a congenital abnormality resulting in an inflammatory response and microglial cell activation both clinically and in animal models. Previously, we reported a mutation in a motile cilia gene, Ccdc39 that develops neonatal progressive hydrocephalus (prh) with inflammatory microglia. We discovered significantly increased amoeboid-shaped activated microglia in periventricular white matter edema, reduced mature homeostatic microglia in grey matter, and reduced myelination in the prh model. Recently, the role of microglia in animal models of adult brain disorders was examined using cell type-specific ablation by colony-stimulating factor-1 receptor (CSF1R) inhibitor, however, little information exists regarding the role of microglia in neonatal brain disorders such as hydrocephalus. Therefore, we aim to see if ablating pro-inflammatory microglia, and thus suppressing the inflammatory response, in a neonatal hydrocephalic mouse line could have beneficial effects. METHODS: In this study, Plexxikon 5622 (PLX5622), a CSF1R inhibitor, was subcutaneously administered to wild-type (WT) and prh mutant mice daily from postnatal day (P) 3 to P7. MRI-estimated brain volume was compared with untreated WT and prh mutants P7-9 and immunohistochemistry of the brain sections was performed at P8 and P18-21. RESULTS: PLX5622 injections successfully ablated IBA1-positive microglia in both the WT and prh mutants at P8. Of the microglia that are resistant to PLX5622 treatment, there was a higher percentage of amoeboid-shaped microglia, identified by morphology with retracted processes. In PLX-treated prh mutants, there was increased ventriculomegaly and no change in the total brain volume was observed. Also, the PLX5622 treatment significantly reduced myelination in WT mice at P8, although this was recovered after full microglia repopulation by P20. Microglia repopulation in the mutants worsened hypomyelination at P20. CONCLUSIONS: Microglia ablation in the neonatal hydrocephalic brain does not improve white matter edema, and actually worsens ventricular enlargement and hypomyelination, suggesting critical functions of homeostatic ramified microglia to better improve brain development with neonatal hydrocephalus. Future studies with detailed examination of microglial development and status may provide a clarification of the need for microglia in neonatal brain development.

Engineered fibrotic liver-targeted truncated transforming growth factor ß receptor type II variant for superior anti-liver fibrosis therapy.

Truncated transforming growth factor ß receptor type II (tTßRII) is a promising anti-liver fibrotic candidate because it serves as a trap for binding excessive TGF-ß1 by means of competing with wild type TßRII (wtTßRII). However, the widespread application of tTßRII for the treatment of liver fibrosis has been limited by its poor fibrotic liver-homing capacity. Herein, we designed a novel tTßRII variant Z-tTßRII by fusing the platelet-derived growth factor ß receptor (PDGFßR)-specific affibody ZPDGFßR to the N-terminus of tTßRII. The target protein Z-tTßRII was produced using Escherichia coli expression system. In vitro and in vivo studies showed that Z-tTßRII has a superior specific fibrotic liver-targeting potential via the engagement of PDGFßR-overexpressing activated hepatic stellate cells (aHSCs) in liver fibrosis. Moreover, Z-tTßRII significantly inhibited cell migration and invasion, and downregulated fibrosis- and TGF-ß1/Smad pathway-related protein levels in TGF-ß1-stimiluated HSC-T6 cells. Furthermore, Z-tTßRII remarkably ameliorated liver histopathology, mitigated the fibrosis responses and blocked TGF-ß1/Smad signaling pathway in CCl4-induced liver fibrotic mice. More importantly, Z-tTßRII exhibits a higher fibrotic liver-targeting potential and stronger anti-fibrotic effects than either its parent tTßRII or former variant BiPPB-tTßRII (PDGFßR-binding peptide BiPPB modified tTßRII). In addition, Z-tTßRII shows no significant sign of potential side effects in other vital organs in liver fibrotic mice. Taken together, we conclude that Z-tTßRII with its a high fibrotic liver-homing potential, holds a superior anti-fibrotic activity in liver fibrosis in vitro and in vivo, which may be a potential candidate for targeted therapy for liver fibrosis.

Structure-Activity Relationship Analysis of Rhosin, a RhoA GTPase Inhibitor, Reveals a New Class of Antiplatelet Agents.

Current antiplatelet therapies have several clinical complications and are mostly irreversible in terms of suppressing platelet activity; hence, there is a need to develop improved therapeutic agents. Previous studies have implicated RhoA in platelet activation. Here, we further characterized the lead RhoA inhibitor, Rhosin/G04, in platelet function and present structure-activity relationship (SAR) analysis. A screening for Rhosin/G04 analogs in our chemical library by similarity and substructure searches revealed compounds that showed enhanced antiplatelet activity and suppressed RhoA activity and signaling. A screening for Rhosin/G04 analogs in our chemical library using similarity and substructure searches revealed compounds that showed enhanced antiplatelet activity and suppressed RhoA activity and signaling. SAR analysis revealed that the active compounds have a quinoline group optimally attached to the hydrazine at the 4-position and halogen substituents at the 7- or 8-position. Having indole, methylphenyl, or dichloro-phenyl substituents led to better potency. Rhosin/G04 contains a pair of enantiomers, and S-G04 is significantly more potent than R-G04 in inhibiting RhoA activation and platelet aggregation. Furthermore, the inhibitory effect is reversible, and S-G04 is capable of inhibiting diverse-agonist-stimulated platelet activation. This study identified a new generation of small-molecule RhoA inhibitors, including an enantiomer capable of broadly and reversibly modulating platelet activity.

An Insight into the Combined Toxicity of 3,4-Dichloroaniline with Two-Dimensional Nanomaterials: From Classical Mixture Theory to Structure-Activity Relationship.

The assessment and prediction of the toxicity of engineered nanomaterials (NMs) present in mixtures is a challenging research issue. Herein, the toxicity of three advanced two-dimensional nanomaterials (TDNMs), in combination with an organic chemical (3,4-dichloroaniline, DCA) to two freshwater microalgae (Scenedesmus obliquus and Chlorella pyrenoidosa), was assessed and predicted not only from classical mixture theory but also from structure-activity relationships. The TDNMs included two layered double hydroxides (Mg-Al-LDH and Zn-Al-LDH) and a graphene nanoplatelet (GNP). The toxicity of DCA varied with the type and concentration of TDNMs, as well as the species. The combination of DCA and TDNMs exhibited additive, antagonistic, and synergistic effects. There is a linear relationship between the different levels (10, 50, and 90%) of effect concentrations and a Freundlich adsorption coefficient (KF) calculated by isotherm models and adsorption energy (Ea) obtained in molecular simulations, respectively. The prediction model incorporating both parameters KF and Ea had a higher predictive power for the combined toxicity than the classical mixture model. Our findings provide new insights for the development of strategies aimed at evaluating the ecotoxicological risk of NMs towards combined pollution situations.

CSF1R-Mediated Myeloid Cell Depletion Prolongs Lifespan But Aggravates Distinct Motor Symptoms in a Model of Multiple System Atrophy.

As the CNS-resident macrophages and member of the myeloid lineage, microglia fulfill manifold functions important for brain development and homeostasis. In the context of neurodegenerative diseases, they have been implicated in degenerative and regenerative processes. The discovery of distinct activation patterns, including increased phagocytosis, indicated a damaging role of myeloid cells in multiple system atrophy (MSA), a devastating, rapidly progressing atypical parkinsonian disorder. Here, we analyzed the gene expression profile of microglia in a mouse model of MSA (MBP29-hα-syn) and identified a disease-associated expression profile and upregulation of the colony-stimulating factor 1 (Csf1). Thus, we hypothesized that CSF1 receptor-mediated depletion of myeloid cells using PLX5622 modifies the disease progression and neuropathological phenotype in this mouse model. Intriguingly, sex-balanced analysis of myeloid cell depletion in MBP29-hα-syn mice revealed a two-faced outcome comprising an improved survival rate accompanied by a delayed onset of neurological symptoms in contrast to severely impaired motor functions. Furthermore, PLX5622 reversed gene expression profiles related to myeloid cell activation but reduced gene expression associated with transsynaptic signaling and signal release. While transcriptional changes were accompanied by a reduction of dopaminergic neurons in the SNpc, striatal neuritic density was increased upon myeloid cell depletion in MBP29-hα-syn mice. Together, our findings provide insight into the complex, two-faced role of myeloid cells in the context of MSA emphasizing the importance to carefully balance the beneficial and adverse effects of CSF1R inhibition in different models of neurodegenerative disorders before its clinical translation.SIGNIFICANCE STATEMENT Myeloid cells have been implicated as detrimental in the disease pathogenesis of multiple system atrophy. However, long-term CSF1R-dependent depletion of these cells in a mouse model of multiple system atrophy demonstrates a two-faced effect involving an improved survival associated with a delayed onset of disease and reduced inflammation which was contrasted by severely impaired motor functions, synaptic signaling, and neuronal circuitries. Thus, this study unraveled a complex role of myeloid cells in multiple system atrophy, which indicates important functions beyond the previously described disease-associated, destructive phenotype and emphasized the need of further investigation to carefully and individually fine-tune immunologic processes in different neurodegenerative diseases.

Predicting Combined Effects of Chemical Stressors: Population-Level Effects of Organic Chemical Mixtures with a Dynamic Energy Budget Individual-Based Model.

Most regulatory ecological risk-assessment frameworks largely disregard discrepancies between the laboratory, where effects of single substances are assessed on individual organisms, and the real environment, where organisms live together in populations and are often exposed to multiple simultaneously occurring substances. We assessed the capability of individual-based models (IBMs) with a foundation in the dynamic energy budget (DEB) theory to predict combined effects of chemical mixtures on populations when they are calibrated on toxicity data of single substances at the individual level only. We calibrated a DEB-IBM for Daphnia magna for four compounds (pyrene, dicofol, α-hexachlorocyclohexane, and endosulfan), covering different physiological modes of action. We then performed a 17-week population experiment with D. magna (designed using the DEB-IBM), in which we tested mixture combinations of these chemicals at relevant concentrations, in a constant exposure phase (7-week exposure and recovery), followed by a pulsed exposure phase (3-day pulse exposure and recovery). The DEB-IBM was validated by comparing blind predictions of mixture toxicity effects with the population data. The DEB-IBM accurately predicted mixture toxicity effects on population abundance in both phases when assuming independent action at the effect mechanism level. The population recovery after the constant exposure was well predicted, but recovery after the pulse was not. The latter could be related to insufficient consideration of stochasticity in experimental design, model implementation, or both. Importantly, the mechanistic DEB-IBM performed better than conventional statistical mixture assessment methods. We conclude that the DEB-IBM, calibrated using only single-substance individual-level toxicity data, produces accurate predictions of population-level mixture effects and can therefore provide meaningful contributions to ecological risk assessment of environmentally realistic mixture exposure scenarios. Environ Toxicol Chem 2022;41:2240-2258. © 2022 SETAC.

Developing random forest based QSAR models for predicting the mixture toxicity of TiO2 based nano-mixtures to Daphnia magna.

During emission, TiO2 nanoparticles (NPs) might meet various chemicals, including metal ions and organic compounds in aquatic environments (e.g., surface water, sediments). At environmentally safe concentrations, combinations of both TiO2 NPs and those chemicals might cause cocktail effects (i.e., mixture toxicity) to aquatic organisms. Previous models such as concentration addition and independent action require dose-response curves of single components in the mixtures to predict the mixture toxicity. Structure-activity relationship (QSAR) models might predict the toxicity of nano-mixtures without dose-response curves of single components in the mixtures. However, current quantitative structure-activity relationship (QSAR) models are mainly focused on predicting cytotoxicity (i.e., cell viability) of heterogeneous metallic TiO2 nanoparticles (NPs) or mixtures of TiO2 NPs and four metal ions (Cu2+, Cd2+, Ni2+, and Zn2+). To minimize the experimental cost of nano-mixture risk assessment, in this study, we developed novel nano-mixture QSAR models to predict i) EC50 of 76 nano-mixtures containing TiO2 NPs and one of eight inorganic/organic compounds (i.e., AgNO3, Cd(NO3)2, Cu(NO3)2, CuSO4, Na2HAsO4, NaAsO2, Benzylparaben and Benzophenone-3), to Daphnia magna(D. magna), and ii) immobilization of D. magna exposed to one of 98 mixtures containing TiO2 NPs and one of eleven inorganic/organic compounds (i.e., AgNO3, Cd(NO3)2, Cu(NO3)2, CuSO4, Na2HAsO4, NaAsO2, Benzylparaben Benzophenone-3, Pirimicarb, Pentabromodiphenyl Ether and Triton X-100). The nano-mixture QSAR models were developed with mixture descriptors (Dmix) combing quantum descriptors of mixture components (e.g., TiO2 NPs and its partners) by using different machine learning techniques (i.e., random forest, neural network, support vector machine, and multiple linear regression). Nano-mixture QSAR models built with the random forest algorithm and proposed mixture descriptors exhibited good performance for predicting logEC50 (Adj.R2test = 0.955 ± 0.003, RMSEtest = 0.016 ± 0.002, and MAEtest = 0.008 ± 0.001) and immobilization (Adj.R2test = 0.888 ± 0.011, RMSEtest = 11.327 ± 0.730, and MAEtest = 5.933 ± 0.442). The models developed in this study were implemented in a user-friendly application for assessing the aquatic toxicity of TiO2 based nano-mixtures.

Spontaneous and TMS-related EEG changes as new biomarkers to measure anti-epileptic drug effects.

Robust biomarkers for anti-epileptic drugs (AEDs) activity in the human brain are essential to increase the probability of successful drug development. The frequency analysis of electroencephalographic (EEG) activity, either spontaneous or evoked by transcranial magnetic stimulation (TMS-EEG) can provide cortical readouts for AEDs. However, a systematic evaluation of the effect of AEDs on spontaneous oscillations and TMS-related spectral perturbation (TRSP) has not yet been provided. We studied the effects of Lamotrigine, Levetiracetam, and of a novel potassium channel opener (XEN1101) in two groups of healthy volunteers. Levetiracetam suppressed TRSP theta, alpha and beta power, whereas Lamotrigine decreased delta and theta but increased the alpha power. Finally, XEN1101 decreased TRSP delta, theta, alpha and beta power. Resting-state EEG showed a decrease of theta band power after Lamotrigine intake. Levetiracetam increased theta, beta and gamma power, while XEN1101 produced an increase of delta, theta, beta and gamma power. Spontaneous and TMS-related cortical oscillations represent a powerful tool to characterize the effect of AEDs on in vivo brain activity. Spectral fingerprints of specific AEDs should be further investigated to provide robust and objective biomarkers of biological effect in human clinical trials.

Triazine-based porous organic polymers for reversible capture of iodine and utilization in antibacterial application.

The capture and safe storage of radioactive iodine (129I or 131I) are of a compelling significance in the generation of nuclear energy and waste storage. Because of their physiochemical properties, Porous Organic Polymers (POPs) are considered to be one of the most sought classes of materials for iodine capture and storage. Herein, we report on the preparation and characterization of two triazine-based, nitrogen-rich, porous organic polymers, NRPOP-1 (SABET = 519 m2 g-1) and NRPOP-2 (SABET = 456 m2 g-1), by reacting 1,3,5-triazine-2,4,6-triamine or 1,4-bis-(2,4-diamino-1,3,5-triazine)-benzene with thieno[2,3-b]thiophene-2,5-dicarboxaldehyde, respectively, and their use in the capture of volatile iodine. NRPOP-1 and NRPOP-2 showed a high adsorption capacity of iodine vapor with an uptake of up to 317 wt % at 80 °C and 1 bar and adequate recyclability. The NRPOPs were also capable of removing up to 87% of iodine from 300 mg L-1 iodine-cyclohexane solution. Furthermore, the iodine-loaded polymers, I2@NRPOP-1 and I2@NRPOP-2, displayed good antibacterial activity against Micrococcus luteus (ML), Escherichia coli (EC), and Pseudomonas aeruginosa (PSA). The synergic functionality of these novel polymers makes them promising materials to the environment and public health.

Developing a Mathematical Model of Intracellular Calcium Dynamics for Evaluating Combined Anticancer Effects of Afatinib and RP4010 in Esophageal Cancer.

Targeting dysregulated Ca2+ signaling in cancer cells is an emerging chemotherapy approach. We previously reported that store-operated Ca2+ entry (SOCE) blockers, such as RP4010, are promising antitumor drugs for esophageal cancer. As a tyrosine kinase inhibitor (TKI), afatinib received FDA approval to be used in targeted therapy for patients with EGFR mutation-positive cancers. While preclinical studies and clinical trials have shown that afatinib has benefits for esophageal cancer patients, it is not known whether a combination of afatinib and RP4010 could achieve better anticancer effects. Since TKI can alter intracellular Ca2+ dynamics through EGFR/phospholipase C-γ pathway, in this study, we evaluated the inhibitory effect of afatinib and RP4010 on intracellular Ca2+ oscillations in KYSE-150, a human esophageal squamous cell carcinoma cell line, using both experimental and mathematical simulations. Our mathematical simulation of Ca2+ oscillations could fit well with experimental data responding to afatinib or RP4010, both separately or in combination. Guided by simulation, we were able to identify a proper ratio of afatinib and RP4010 for combined treatment, and such a combination presented synergistic anticancer-effect evidence by experimental measurement of intracellular Ca2+ and cell proliferation. This intracellular Ca2+ dynamic-based mathematical simulation approach could be useful for a rapid and cost-effective evaluation of combined targeting therapy drugs.

Cortical diurnal rhythms remain intact with microglial depletion.

Microglia are subject to change in tandem with the endogenously generated biological oscillations known as our circadian rhythm. Studies have shown microglia harbor an intrinsic molecular clock which regulates diurnal changes in morphology and influences inflammatory responses. In the adult brain, microglia play an important role in the regulation of condensed extracellular matrix structures called perineuronal nets (PNNs), and it has been suggested that PNNs are also regulated in a circadian and diurnal manner. We sought to determine whether microglia mediate the diurnal regulation of PNNs via CSF1R inhibitor dependent microglial depletion in C57BL/6J mice, and how the absence of microglia might affect cortical diurnal gene expression rhythms. While we observe diurnal differences in microglial morphology, where microglia are most ramified at the onset of the dark phase, we do not find diurnal differences in PNN intensity. However, PNN intensity increases across many brain regions in the absence of microglia, supporting a role for microglia in the regulation of PNNs. Here, we also show that cortical diurnal gene expression rhythms are intact, with no cycling gene changes without microglia. These findings demonstrate a role for microglia in the maintenance of PNNs, but not in the maintenance of diurnal rhythms.

Microglia control glutamatergic synapses in the adult mouse hippocampus.

Microglia cells are active players in regulating synaptic development and plasticity in the brain. However, how they influence the normal functioning of synapses is largely unknown. In this study, we characterized the effects of pharmacological microglia depletion, achieved by administration of PLX5622, on hippocampal CA3-CA1 synapses of adult wild type mice. Following microglial depletion, we observed a reduction of spontaneous and evoked glutamatergic activity associated with a decrease of dendritic spine density. We also observed the appearance of immature synaptic features and higher levels of plasticity. Microglia depleted mice showed a deficit in the acquisition of the Novel Object Recognition task. These events were accompanied by hippocampal astrogliosis, although in the absence ofneuroinflammatory condition. PLX-induced synaptic changes were absent in Cx3cr1-/- mice, highlighting the role of CX3CL1/CX3CR1 axis in microglia control of synaptic functioning. Remarkably, microglia repopulation after PLX5622 withdrawal was associated with the recovery of hippocampal synapses and learning functions. Altogether, these data demonstrate that microglia contribute to normal synaptic functioning in the adult brain and that their removal induces reversible changes in organization and activity of glutamatergic synapses.