Multiphoton Resonance Meets Tunneling Ionization: High-Efficient Photoexcitation in Strong-Field-Dressed Ions.

Tunneling ionization, a fascinating quantum phenomenon, has played the key role in the development of attosecond physics. Upon absorption of a few tens of photons, tunneling ionization creates ions in different excited states and even enables the formation of population inversion between ionic states. However, the underlying physics is still being debated. Here, we demonstrate a significant enhancement in the efficiency of multiphoton excitation when ionization of neutral molecules and resonant excitation of ions coexist in strong laser fields. It facilitates the dramatic increase in population inversion and lasing radiation in N_{2}^{+} around 1000 nm pump wavelength. Utilizing the ionization-coupling theory, we discover that the synergistic interplay between tunneling ionization and multiphoton excitation enables the ionic coherence to be maximized by phase locking of the periodically created ionic dipoles and consistently maintain an optimal phase for the follow-up photoexcitation. This Letter provides new insights into the photoexcitation mechanism of ions in strong laser fields and opens up a route for optimizing ionic lasing radiations.

Preclinical evaluation of abuse potential of the peripherally-restricted kappa opioid receptor agonist HSK21542.

HSK21542 is a peripherally-restricted kappa opioid receptor (KOR) agonist developed for pain treatment. Because of the CNS pharmacological concern of opioid receptor activation, such as physical dependence and addiction potential, an assessment of abuse potential of HSK21542 was required prior to marketing approval. The preclinical abuse potential assessments for HSK21542 included the following studies: 1) intravenous self-administration study to explore the relative reinforcing efficacy in rats self-administering remifentanil; 2) rat drug discrimination study to examine the pharmacological similarity of the interoceptive or subjective effects of HSK21542 in rats discriminating pentazocine; 3) rat conditioned place preference (CPP) paradigm to test the rewarding effects; 4) rat natural physical dependence-spontaneous withdrawal study in rats chronically treated with HSK21542; 5) naloxone-precipitated withdrawal assay following chronic HSK21542 exposure to evaluate its physical dependence potential. The results showed that HSK21542 was devoid of behavioral evidence of positive reinforcing effect and did not share similar discriminative stimulus effects with pentazocine. HSK21542 also did not produce CPP in rats. In addition, HSK21542 did not produce spontaneous withdrawal or naloxone-precipitated withdrawal in rats with chronic treatments. Collectively, these preclinical findings suggest that HSK21542 has no abuse potential in animals, which demonstrate low abuse potential in humans.

The repeated administration of rhIL-12 for 14 weeks in rhesus monkeys: A toxicity assessment.

Interleukin-12 (IL-12) is known to exert antitumor immune effects by promoting the activation and proliferation of T cells and NK cells within the immune system. However, clinical trials have observed systemic toxicity associated with the administration of IL-12. This has shelved development plans for its use as a cancer therapeutic drug. Therefore, it is critical that we perform a systematic evaluation of the toxicity and safety of repeated IL-12 administration. In this study, we conducted a comprehensive evaluation of the toxicity and safety of repeated rhIL-12 (recombinant human interleukin-12) administration in rhesus monkeys by assessing its effects on the immune system, organ function, and vital signs. Rhesus monkeys were subcutaneously injected with 0.5, 2.5, and 12.5 µg/kg of rhIL-12 for up to for 14 consecutive weeks. The low dose exhibited no signs of toxicity, whereas animals receiving higher doses displayed symptoms such as loose stools, reduced activity, anemia, and elevated liver function indicators (AST and TBIL). Following three administrations of 12.5 µg/kg, high dosing was adjusted to 7.5 µg/kg due to manifestations of symptoms like loose stools, decreased activity, and huddling in the cage. Furthermore, rhesus monkeys exhibited marked immunogenic responses to recombinant human interleukin-12 (rhIL-12). However, based on overall study findings, the No Observed Adverse Effect Level (NOAEL) for the subcutaneous injection of rhIL-12, when repeatedly administered for 3 months in rhesus monkeys, was considered to be 0.5 µg/kg. The Highest Non-Severely Toxic Dose (HNSTD) was considered to be 7.5 µg/kg.

Secretion of human soluble programmed cell death protein 1 by chimeric antigen receptor-modified T cells enhances anti-tumor efficacy.

BACKGROUND AIMS: Chimeric antigen receptor (CAR) T cells have achieved favorable responses in patients with hematologic malignancies, but the outcome has been far from satisfactory in the treatment of tumors with high expression of immunosuppressive molecules. To overcome this limitation, we modified CAR T cells to secrete types of human soluble programmed cell death protein 1 (PD-1) called sPD-1 CAR T cells. METHODS: To compare the effector function between second (conventional second-generation CAR targeting CD19) and sPD-1 CAR T cells, we measured cytotoxicity, cytokine secretion and activation markers incubated with or without tumor cells expressing CD19 and/or programmed cell death ligand 1 (PD-L1). Furthermore, the anti-tumor efficacy of second and sPD-1 CAR T cells was determined using an NSG mouse model bearing NALM-6-PD-L1. Finally, the underlying mechanism was investigated by metabolic parameters and RNA sequencing analysis of different CAR T cells. RESULTS: Compared with second CAR T cells, sPD-1 CAR T cells enhanced killing efficiency toward CD19+PD-L1+ tumor cells in vitro. Furthermore, sPD-1 CAR T cells reduced the tumor burden and prolonged overall survival of the NSG (NOD-SCID-IL2rg) mice bearing NALM-6-PD-L1. To explore the effect of soluble PD-1 on CAR T cells, we found that sPD-1 CAR T cells exhibited higher levels of activation and ameliorative profiles of differentiation, exhaustion, glycolysis and apoptosis. CONCLUSIONS: With constitutive soluble PD-1 secretion, sPD-1 CAR T cells have tended to eradicate tumors with a high expression of PD-L1 more effectively than second CAR T cells. This may be due to soluble PD-1 enhancing apoptosis resistance, aerobic metabolism and a more "stem" differentiation of CAR T cells. Overall, our study presents a feasible strategy to increase the efficacy of CAR T cells.

Transition-metal catalysed C-N bond activation.

Transition-metal catalysed C-N bond activation has attracted much attention and become one of the most promising bond disconnection and formation strategies that encompass a broad spectrum of applications in many reactions. In this tutorial review, efficient strategies for catalytic cleavage of C(sp)-N, C(sp(2))-N and C(sp(3))-N bonds and their applications in new C-C and C-N bond formation reactions are summarized.

Characterizing the mechanism of thiazolidinedione-induced hepatotoxicity: An in vitro model in mitochondria.

OBJECTIVE: To characterize the mechanism of action of thiazolidinedione (TZD)-induced liver mitochondrial toxicity caused by troglitazone, rosiglitazone, and pioglitazone in HepaRG cells. METHODS: Human hepatoma cells (HepaRG) were treated with troglitazone, rosiglitazone, or pioglitazone (12.5, 25, and 50µM) for 48h. The Seahorse Biosciences XF24 Flux Analyzer was used to measure mitochondrial oxygen consumption. The effect of TZDs on reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were detected by flow cytometry. The mitochondrial ultrastructure of HepaRG cells was observed under a transmission electrical microscope (TEM). mtDNA content was evaluated by real-time PCR, and ATP content and mitochondrial respiratory chain (MRC) complex I, II, III, IV activity were measured via chemiluminescence. Results were considered statistically significant at p<0.05. RESULTS: Among the three drugs, troglitazone exhibited the highest potency, followed by rosiglitazone, and then pioglitazone. The TZDs caused varying degrees of mitochondrial respiratory function disorders including decreases in oxygen consumption, MRC activity, and ATP level, and an elevation in ROS level. TZD treatment resulted in mtDNA content decline, reduction in MMP, and alterations of mitochondrial structure. CONCLUSION: All investigated TZDs show a certain degree of mitochondrial toxicity, with troglitazone exhibiting the highest potency. The underlying mechanism of TZD-induced hepatotoxicity may be associated with alterations in mitochondrial respiratory function disorders, oxidative stress, and changes in membrane permeability. These parameters may be used early in drug development to further optimize risk:benefit profiles.

Path analysis for affecting the physical fitness of marine majors: A cross-sectional observational study from the perspective of health.

The physical fitness of marine major students is critically linked to their academic performance and future career prospects. To investigate the influence of various environmental factors on the physical fitness of maritime majors and to identify potential strategies for improving physical fitness among this population. A cross-sectional observational study was conducted among maritime students. The study surveyed and field-tested 517 male marine majors across 1st to 3rd-grade students using a combination of questionnaire surveys and on-site testing methods. There were no significant differences in body mass index (BMI) and social support among these 1st to 3rd-grade students; however, there were differences in sports lifestyle and physical fitness index (PFI). Social support positively correlated with a sports lifestyle. There is no correlation between BMI and PFI. Social support influences the sports lifestyle of marine majors, which in turn affects BMI and PFI. Pleasure-type and fitness-type sports lifestyles serve as mediators between social support and PFI, while BMI is also a mediator between sports lifestyle and PFI. Social support affects the sports lifestyle of marine majors, which affects BMI and directly influences PFI.

Harmonizing Unets: Attention Fusion module in cascaded-Unets for low-quality OCT image fluid segmentation.

Optical coherence tomography (OCT) is widely used for its high resolution. Accurate OCT image segmentation can significantly improve the diagnosis and treatment of retinal diseases such as Diabetic Macular Edema (DME). However, in resource-limited regions, portable devices with low-quality output are more frequently used, severely affecting the performance of segmentation. To address this issue, we propose a novel methodology in this paper, including a dedicated pre-processing pipeline and an end-to-end double U-shaped cascaded architecture, H-Unets. In addition, an Adaptive Attention Fusion (AAF) module is elaborately designed to improve the segmentation performance of H-Unets. To demonstrate the effectiveness of our method, we conduct a bunch of ablation and comparative studies on three open-source datasets. The experimental results show the validity of the pre-processing pipeline and H-Unets, achieving the highest Dice score of 90.60%±0.87% among popular methods in a relatively small model size.

Measurement of Carbon Dioxide Isotopes with Air-Lasing-Based Coherent Raman Spectroscopy.

Isotope detection is crucial for geological research, medical diagnostics, industrial production, and environmental monitoring. Various spectroscopic techniques are continually emerging for isotopic identification and accurate measurement. Herein, coherent Raman scattering (CRS) spectroscopy is developed for the quantitative detection of carbon dioxide isotopes, in which the N2+ air lasing coherently created in the interaction region is used as the probe. Benefiting from the narrow spectral width of air lasing, the Raman peaks of 12CO2 and 13CO2 can be well discerned, although their spectra partially overlap. The overlapped signals were proven to be the result of the coherent superposition of individual Raman signals. Based on that fact, a deconvolution algorithm was designed to retrieve the concentration ratio of the two isotopes. The relative error of the measurement is less than 6%. The CRS technique based on air lasing offers a potential approach for the quantitative characterization of molecular isotopes, especially in application scenarios of remote sensing or in situ detection.

Dendritic-cell-targeting virus-like particles as potent mRNA vaccine carriers.

Messenger RNA vaccines lack specificity for dendritic cells (DCs)-the most effective cells at antigen presentation. Here we report the design and performance of a DC-targeting virus-like particle pseudotyped with an engineered Sindbis-virus glycoprotein that recognizes a surface protein on DCs, and packaging mRNA encoding for the Spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or for the glycoproteins B and D of herpes simplex virus 1. Injection of the DC-targeting SARS-CoV-2 mRNA vaccine in the footpad of mice led to substantially higher and durable antigen-specific immunoglobulin-G titres and cellular immune responses than untargeted virus-like particles and lipid-nanoparticle formulations. The vaccines also protected the mice from infection with SARS-CoV-2 or with herpes simplex virus 1. Virus-like particles with preferential uptake by DCs may facilitate the development of potent prophylactic and therapeutic vaccines.

Gestational and Lactational Co-Exposure to DEHP and BPA Impairs Hepatic Function via PI3K/AKT/FOXO1 Pathway in Offspring.

Di-(2-Ethylhexyl) phthalate (DEHP) and bisphenol A (BPA) present significant environmental endocrine-disrupting chemical properties. Although studies have implied reproductive impairment from exposure to BPA and DEHP, no study to date has shown the effect and mechanism of hepatic function after gestational and lactational co-exposure to DEHP and BPA in offspring. A total of 36 perinatal rats were randomly divided into four groups, DEHP (600 mg/kg/day), BPA (80 mg/kg/day), DEHP combined with BPA (600 mg/kg/day + 80 mg/kg/day), and control. Notably, 11 chemical targets were screened after identifying eight substances associated with chemically-induced hepatic damage. Molecular docking simulations revealed a high-scoring combination of eight metabolic components and targets of the PI3K/AKT/FOXO1 signaling pathway. The DEHP and BPA combination disrupted hepatic steatosis, ultimately affecting systemic the glucose and the lipid metabolic homeostasis with significant toxicity. Mechanistically, co-exposure to DEHP and BPA causes liver dysfunction and hepatic insulin resistance via PI3K/AKT/FOXO1 pathway in offspring. This is the first study of the hepatic function and mechanism of co-exposure to DEHP and BPA that combines metabolomics, molecular docking, and traditional toxicity assessment methods.

An exploration on retro-construction of plasma drug concentration-time curves from corresponding urine excretion data and single-point plasma concentrations using a simplified and idealized method.

Background: Despite the availability of various tools of modeling and simulation, clinical pediatric pharmacokinetic (PK) studies remain far less efficient than those on adults due to ethical constraints. One of the optimal solutions is to substitute urine to blood sampling based on explicit mathematic relationships between them. However, this idea is limited by three main knowledge gaps associated with urine data, i.e., complicated excretion equations with excessive parameters, insufficient frequency that is hard to fit, and the mere expression of amounts with no in vivo distribution volume information involved. Methods: To overcome these obstacles, we sacrificed the precision from mechanistic PK models with complex excretion equations to expediency of compartmental model in which a constant ke is used to cover all the internal parameters. And the total cumulative amounts of urinary drug excretion (Xu∞) were estimated and introduced to the excretion equation so that urine data were likely to be fitted using a semi-log-terminal linear regression method. In addition, urinary excretion clearance (CLr) could be calculated by single point plasma data to anchor the plasma concentration-time (C-t) curve based on the assumption that CLr was kept constant throughout the PK process. Results: After sensitivity analysis of two subjective judgements (the selection of the compartmental model and the selection of plasma time point to calculate CLr), the performance of the optimized models was assessed using desloratadine or busulfan as model drugs in a variety of PK scenarios, from i.v. bolus/infusion to p.o. administration, from a single dose to multiple doses, and from rats to children. The fitting plasma drug concentrations of the optimal model were close to the observed value. Meanwhile, the drawbacks inherent to the simplified and idealized modeling strategy were fully identified. Conclusions: The method proposed by this tentative proof-of-principle study was able to deliver acceptable plasma exposure curves and shed light on the future refinements.

Targeting and cytotoxicity of chimeric antigen receptor T cells grafted with PD1 extramembrane domain.

BACKGROUND: Immunosuppression induced by programmed cell death protein 1 (PD1) presents a significant constraint on the effectiveness of chimeric antigen receptor (CAR)-T therapy. The potential of combining PD1/PDL1 (Programmed cell death 1 ligand 1) axis blockade with CAR-T cell therapy is promising. However, developing a highly efficient and minimally toxic approach requires further exploration. Our attempt to devise a novel CAR structure capable of recognizing both tumor antigens and PDL1 encountered challenges since direct targeting of PDL1 resulted in systemic adverse effects. METHODS: In this research, we innovatively engineered novel CARs by grafting the PD1 domain into a conventional second-generation (2G) CAR specifically targeting CD19. These CARs exist in two distinct forms: one with PD1 extramembrane domain (EMD) directly linked to a transmembrane domain (TMD), referred to as PE CAR, and the other with PD1 EMD connected to a TMD via a CD8 hinge domain (HD), known as PE8HT CAR. To evaluate their efficacy, we conducted comprehensive assessments of their cytotoxicity, cytokine release, and potential off-target effects both in vitro and in vivo using tumor models that overexpress CD19/PDL1. RESULTS: The findings of our study indicate that PE CAR demonstrates enhanced cytotoxicity and reduced cytokine release specifically towards CD19 + PDL1 + tumor cells, without off-target effects to CD19-PDL1 + tumor cells, in contrast to 2G CAR-T cells. Additionally, PE CAR showed ameliorative differentiation, exhaustion, and apoptosis phenotypes as assessed by flow cytometry, RNA-sequencing, and metabolic parameter analysis, after encountering CD19 + PDL1 + tumor cells. CONCLUSION: Our results revealed that CAR grafted with PD1 exhibits enhanced antitumor activity with lower cytokine release and no PD1-related off-target toxicity in tumor models that overexpress CD19 and PDL1. These findings suggest that our CAR design holds the potential for effectively addressing the PD1 signal.

Preclinical safety of a bionic tiger bone capsule in Sprague-Dawley rats and beagle dogs.

BACKGROUND: Jintiange capsule is composed of bionic tiger bone powder and has similar ingredients to natural tiger bone. OBJECTIVE: To characterize the subacute toxicities of Jintiange capsule in rats and beagle dogs for preclinical safety assessment. METHODS: Suspensions of Jintiange capsule were given via gastric lavage over a 26-week period at low (500 mg/kg), mid (1500 mg/kg) and high doses (4000 mg/kg) in SD rats. Beagles were given by gastric lavage of suspensions of Jintiange capsule once daily for 6 days per week for 39 weeks at low (300 mg/kg), mid (900 mg/kg) or high dose (2000 mg/kg). RESULTS: Repeated gastric lavages of suspensions of Jintiange capsule at doses from 500 to 4000 mg/kg over 26 weeks caused no significant toxicity (No Observed Adverse Effect Level, NOAEL) in rats. In addition, repeated gastric lavages of suspensions of Jintiange capsule at doses from 300 to 2000 mg/kg over 39 weeks caused NOAEL in beagles. CONCLUSIONS: Jintiange capsule was safe in rats at a dose 66.7 times the clinically recommended dose and in beagles at 33.3 times the clinically recommended dose. Our subacute toxicity studies in rats and beagles demonstrated no apparent overall toxicities including haematotoxicities, hepatotoxicities and renal toxicities.

Plasmid parB contributes to uropathogenic Escherichia coli colonization in vivo by acting on biofilm formation and global gene regulation.

The endogenous plasmid pUTI89 harbored by the uropathogenic Escherichia coli (UPEC) strain UTI89 plays an important role in the acute stage of infection. The partitioning gene parB is important for stable inheritance of pUTI89. However, the function of partitioning genes located on the plasmid in pathogenesis of UPEC still needs to be further investigated. In the present study, we observed that disruption of the parB gene leads to a deficiency in biofilm formation in vitro. Moreover, in a mixed infection with the wild type strain and the parB mutant, in an ascending UTI mouse model, the mutant displayed a lower bacterial burden in the bladder and kidneys, not only at the acute infection stage but also extending to 72 hours post infection. However, in the single infection test, the reduced colonization ability of the parB mutant was only observed at six hpi in the bladder, but not in the kidneys. The colonization capacity in vivo of the parB-complemented strain was recovered. qRT-PCR assay suggested that ParB could be a global regulator, influencing the expression of genes located on both the endogenous plasmid and chromosome, while the gene parA or the operon parAB could not. Our study demonstrates that parB contributes to the virulence of UPEC by influencing biofilm formation and proposes that the parB gene of the endogenous plasmid could regulate gene expression globally.

Proteomics unite traditional toxicological assessment methods to evaluate the toxicity of iron oxide nanoparticles.

Iron oxide nanoparticles (IONPs) are the first generation of nanomaterials approved by the Food and Drug Administration for use as imaging agents and for the treatment of iron deficiency in chronic kidney disease. However, several IONPs-based imaging agents have been withdrawn because of toxic effects and the poor understanding of the underlying mechanisms. This study aimed to evaluate IONPs toxicity and to elucidate the underlying mechanism after intravenous administration in rats. Seven-week-old rats were intravenously administered IONPs at doses of 0, 10, 30, and 90 mg/kg body weight for 14 consecutive days. Toxicity and molecular perturbations were evaluated using traditional toxicological assessment methods and proteomics approaches, respectively. The administration of 90 mg/kg IONPs induced mild toxic effects, including abnormal clinical signs, lower body weight gain, changes in serum biochemical and hematological parameters, and increased organ coefficients in the spleen, liver, heart, and kidneys. Toxicokinetics, tissue distribution, histopathological, and transmission electron microscopy analyses revealed that the spleen was the primary organ for IONPs elimination from the systemic circulation and that the macrophage lysosomes were the main organelles of IONPs accumulation after intravenous administration. We identified 197 upregulated and 75 downregulated proteins in the spleen following IONPs administration by proteomics. Mechanically, the AKT/mTOR/TFEB signaling pathway facilitated autophagy and lysosomal activation in splenic macrophages. This is the first study to elucidate the mechanism of IONPs toxicity by combining proteomics with traditional methods for toxicity assessment.

Reducing Hinge Flexibility of CAR-T Cells Prolongs Survival In Vivo With Low Cytokines Release.

Chimeric antigen receptor (CAR)-modified T cells targeting CD19 demonstrate unparalleled responses in B cell malignancies. However, high tumor burden limits clinical efficacy and increases the risk of cytokine release syndrome and neurotoxicity, which is associated with over-activation of the CAR-T cells. The hinge domain plays an important role in the function of CAR-T cells. We hypothesized that deletion of glycine, an amino acid with good flexibility, may reduce the flexibility of the hinge region, thereby mitigating CAR-T cell over-activation. This study involved generating a novel CAR by deletion of two consecutive glycine residues in the CD8 hinge domain of second-generation (2nd) CAR, thereafter named 2nd-GG CAR. The 2nd-GG CAR-T cells showed similar efficacy of CAR expression but lower hinge flexibility, and its protein affinity to CD19 protein was lower than that of 2nd CAR-T cells. Compared to the 2nd CAR-T cells, 2nd-GG CAR-T cells reduced proinflammatory cytokine secretion without diminishing the specific cytotoxicity toward tumor cells in vitro. Furthermore, 2nd-GG CAR-T cells prolonged overall survival in an immunodeficient mouse model bearing NALM-6 when tumor burden was high. This study demonstrated that a lower-flexibility of CD8α hinge improved survival under high tumor burden and reduced proinflammatory cytokines in preclinical studies. While there is potential for improved safety and efficacy, yet this needs validation with clinical trials.

Plasma and liver proteomic analysis of 3Z-3-[(1H-pyrrol-2-yl)-methylidene]-1-(1-piperidinylmethyl)-1,3-2H-indol-2-one-induced hepatotoxicity in Wistar rats.

3Z-3-[(1H-pyrrol-2-yl)-methylidene]-1-(1-piperidinylmethyl)-1,3-2H-indol-2-one (Z24), a synthetic anti-angiogenic compound, inhibits the growth and metastasis of certain tumors. Previous works have shown that Z24 induces hepatotoxicity in rodents. We examined the hepatotoxic mechanism of Z24 at the protein level and looked for potential biomarkers. We used 2-DE and MALDI-TOF/TOF MS to analyze alternatively expressed proteins in rat liver and plasma after Z24 administration. We also examined apoptosis in rat liver and measured levels of intramitochondrial ROS and NAD(P)H redox in liver cells. We found that 22 nonredundant proteins in the liver and 11 in the plasma were differentially expressed. These proteins were involved in several important metabolic pathways, including carbohydrate, lipid, amino acid, and energy metabolism, biotransformation, apoptosis, etc. Apoptosis in rat liver was confirmed with the terminal deoxynucleotidyl transferase dUTP-nick end labeling assay. In mitochondria, Z24 increased the ROS and decreased the NAD(P)H levels. Thus, inhibition of carbohydrate aerobic oxidation, fatty acid beta-oxidation, and oxidative phosphorylation is a potential mechanism of Z24-induced hepatotoxicity, resulting in mitochondrial dysfunction and apoptosis-mediated cell death. In addition, fetub protein and argininosuccinate synthase in plasma may be potential biomarkers of Z24-induced hepatotoxicity.

Systems toxicology used in nanotoxicology: mechanistic insights into the hepatotoxicity of nano-copper particles from toxicogenomics.

In some studies, nano-copper particles have been found to be acutely toxic to exposed mice, with the liver and kidney being the target tissues. However, the characteristics of subacute toxicity from repeated nano-copper exposure in rats and the molecular mechanism of its hepatotoxicity at the genomic level remain unclear. We investigated the mechanisms of nano-copper-induced hepatotoxicity, which were identified from hepatic gene expression profiles that were phenotypically anchored to conventional toxicological outcomes, and identified biomarkers of nanotoxicity caused by nano-copper. Male Wistar rats were administered nano-copper or micro-copper at different doses for five days. Subsequently, we examined conventional toxicological parameters including body weight, clinical chemistry, and histopathology, and also used microarrays to identify gene expression changes in rat liver. High dose nano-copper induced increases in alanine aminotransferase, aspartate aminotransferase, triglyceride, total bilirubin, total bile acid levels, and a decrease in body weight. Histopathological studies of the liver indicated scattered, dotted hepatocytic necrosis in all rats in the high dose nano-copper group. Identified genes from the group receiving the high dose were functionally categorized, and results showed that genes related to oxidoreductase activity, metabolism, and signal transduction were involved in the development of the observed phenotypes. The results also suggest that altered gene expression patterns induced by exposure to a low, subtoxic dose of nano-copper may reveal signs of cell stress or subtle cell injury indicative of overt toxicity at higher doses. Results in this study provide new insights into the toxicology of nano-copper particles and illustrate how toxicogenomic approaches are providing an unprecedented amount of mechanistic information on molecular responses to nano-copper, as well as how they are likely to impact hazard and risk assessment. Gene expression changes are likely to be more sensitive indicators of potential adverse effects than traditional measurements of toxicity.

Toxicological evaluation of z24, a novel indolin-2-ketone compound, in cultured human liver cells using toxicogenomic techniques.

The current study was designed to investigate the toxicity of 3Z-3-[((1)H-pyrrol-2-yl)-methylidene]-1-(1-piperidinylmethyl)-1, 3-2H-indol-2-one (Z24), a novel synthetic indolin-2-ketone small molecule compound, using toxicogenomic techniques (complementary DNA [cDNA] microarray). Bioinformatic analysis suggested that the main functions of genes with altered expression were consistent with liver cell regeneration, apoptosis, metabolism of energy and fat, and the death receptor (DR)-mediated apoptosis-signaling pathway. Death receptor 4, Bcl-2, Bcl-xl, caspase 3, and cytochrome C, which are involved in the DR-mediated apoptosis-signaling pathway, were altered after Z24 treatment as determined by Western blotting analysis. When hepatocarcinoma cell line (HepG2 cells) treated with Z24 at 0.248 mmol/L for 24 hours, DNA fragmentation reached a maximum, and examination of cell morphology showed typical signs of apoptosis. These results indicate that Z24 can initiate apoptosis in hepatocytes, which in turn causes hepatotoxicity. A possible toxicological mechanism is that apoptosis was induced in hepatocytes by initiating the DR-mediated signal transduction pathway. Apoptosis of hepatocytes might lead to impairment of energy and lipid metabolism and provoke hepatocyte necrosis or inflammation, resulting in hepatotoxicity.