The enantioselective study of the toxicity effects of chiral acetochlor in HepG2 cells

Design, synthesis and biological evaluation of matrine contains benzimidazole derivatives as dual TOPOI and PARP inhibitors for cancer therapy

TOPOI inhibitors have long been a focal point in the research and development of antitumor drugs. PARP-1 plays a crucial role in repairing DNA damage induced by TOPOI inhibitors. Thus, concurrent inhibition of TOPOI and PARP-1 has the potential to augment drug activity. Matrine, characterized by low toxicity and good water solubility, offers advantageous properties. In this investigation, a series of benzimidazole matrine derivatives were designed and synthesized using matrine as the lead compound with the aim of developing dual inhibitors targeting both TOPOI and PARP-1. Among these derivatives, Compound B6 exhibited potent inhibitory effects on PARP-1 and TOPOI, effectively suppressing cancer cell proliferation and migration. Mechanistic assessments revealed that B6 induced DNA damage in HGC-27 cells, leading to G0/G1 cell cycle arrest and significant apoptosis. Molecular docking experiments demonstrated that B6 can effectively enter the active pocket of target proteins, where it forms stable hydrogen bonds with amino acid residues. In vivo, experiments demonstrated that B6 exhibited antitumor activity comparable to that of the positive control drug. The tumor growth inhibition rates (TGIs) for irinotecan, B6 and matrine were 87.0%, 75.4% and 9.7%, respectively. Importantly, B6 demonstrated lower toxicity than the positive control drug. Our findings suggest that TOPOI and PARP-1 may represent potential targets for matrine and B6 emerges as a promising candidate for cancer therapy.

Stereoselective toxicity of acetochlor chiral isomers on the nervous system of zebrafish larvae

Acetochlor (ACT) is a widely detected pesticide globally, and the neurotoxic effects of its chiral isomers on humans and environmental organisms remain uncertain. Zebrafish were used to study the neurotoxicity of ACT and its chiral isomers. Our study reveals that the R-ACT, Rac-ACT, and S-ACT induce neurotoxicity in zebrafish larvae by impairing vascular development and disrupting the blood-brain barrier. These detrimental effects lead to apoptosis in brain cells, hindered development of the central nervous system, and manifest as altered swimming behavior and social interactions in the larvae. Importantly, the neurotoxicity caused by the S-ACT exhibits the most pronounced impact and significantly diverges from the effects induced by the R-ACT. The neurotoxicity associated with the Rac-ACT falls intermediate between that of the R-ACT and S-ACT. Fascinatingly, we observed a remarkable recovery in the S-ACT-induced abnormalities in BBB, neurodevelopment, and behavior in zebrafish larvae upon supplementation of the Wnt/β-catenin signaling pathway. This observation strongly suggests that the Wnt/β-catenin signaling pathway serves as a major target of S-ACT-induced neurotoxicity in zebrafish larvae. In conclusion, S-ACT significantly influences zebrafish larval neurodevelopment by inhibiting the Wnt/β-catenin signaling pathway, distinguishing it from R-ACT neurotoxic effects.

Chiral Carbon Dots and Chiral Carbon Dots with Circularly Polarized Luminescence: Synthesis, Mechanistic Investigation and Applications

Chiral carbon dots (CCDs) can be widely used in various fields such as chiral recognition, chiral catalysis and biomedicine because of their unique optical properties, low toxicity and good biocompatibility. In addition, CCDs with circularly polarized luminescence (CPL) can be synthesized, thus broadening the prospects of CCDs applications. Since the research on CCDs is still in its infancy, this paper reviews the chiral origin, formation mechanism, chiral evolution, synthesis and emerging applications of CCDs, with a special focus on CCDs with CPL activity. It is hoped that it will provide some reference to solve the current problems faced by CCDs. Finally, the opportunities and challenges of the current research on CCDs are described, and their future development trends have also been prospected.

Molecular mechanisms of cardiotoxicity induced by acetamide and its chiral isomers

Acetamide (ACT) is used in a racemic form, and the considerable residues of this compound in the environment raise potential safety concerns for human health. We investigated the toxicity of ACT and its chiral isomers on human cardiomyocyte (AC16) cell line and zebrafish embryonic heart, and found that (+)-S-ACT was the main component causing cardiac toxicity. Our findings indicate that the IC50 of (±)-Rac-ACT on AC16 cells was 20.19 μg/mL. (-)-R-ACT, (±)-Rac-ACT, and (+)-S-ACT caused DNA damage and apoptosis in AC16 cells at this concentration. The underlying molecular mechanism may involve the induction of reactive oxygen species (ROS). The accumulation of ROS results in a decline in mitochondrial membrane potential (MMP) and prompts the release of cytochrome c (cyt c) from the mitochondria. This cascade of events ultimately activates the caspase-3 and caspase-9 signaling pathways, resulting in apoptosis. Furthermore, in vivo observations in zebrafish hearts demonstrated caspase-3 activation and the presence of the DNA damage marker (γH2AX), indicating that (+)-S-ACT is more toxic to cardiomyocytes than (-)-R-ACT and (±)-Rac-ACT. These findings suggest that (+)-S-ACT may be the primary component responsible for the toxicity of (±)-Rac-ACT in AC16 cells. Overall, these findings raise public awareness regarding the risks associated with chiral isomeric pesticides and provide a scientific foundation for their appropriate use.

Developmental and cardiovascular toxicities of acetochlor and its chiral isomers in zebrafish embryos through oxidative stress

Acetochlor (ACT) is a widely used pesticide, yet the environmental and health safety of its chiral isomers remains inadequately evaluated. In this study, we evaluated the toxicity of ACT and its chiral isomers in a zebrafish model. Our findings demonstrate that ACT and its chiral isomers disrupt early zebrafish embryo development, inducing oxidative stress, abnormal lipid metabolism, and apoptosis. Additionally, ACT and its chiral isomers lead to cardiovascular damage, including reduced heart rate, decreased red blood cell (RBC) flow rate, and vascular damage. We further observed that (+)-S-ACT has a significant impact on the transcription of genes involved in cardiac and vascular development, including tbx5, hand2, nkx2.5, gata4, vegfa, dll4, cdh5, and vegfc. Our study highlights the potential risk posed by different conformations of chiral isomeric pesticides and raises concerns regarding their impact on human health. Overall, our results suggest that the chiral isomers of ACT induce developmental defects and cardiovascular toxicity in zebrafish, with (+)-S-ACT being considerably more toxic to zebrafish than (-)-R-ACT.

The health risk of acetochlor metabolite CMEPA is associated with lipid accumulation induced liver injury

Liver injury may cause many diseases, such as non-alcoholic fatty liver disease (NAFLD). Acetochlor is one of the representative chloroacetamide herbicides, and its metabolite 2-chloro-N-(2-ethyl-6-methyl phenyl) acetamide (CMEPA) is the main form of exposure in the environment. It has been shown that acetochlor can cause mitochondrial damage of HepG2 cells and induce apoptosis by activating Bcl/Bax pathway (Wang et al., 2021). But there has been less research on CMEPA. we explored the possibility of CMEPA and liver injury through biological experiments. In vivo, CMEPA (0-16 mg/L) induced liver damage in zebrafish larvae, including increased lipid droplets, changes in liver morphology (>1.3-fold) and increased TC/TG content (>2.5-fold). In vitro, we selected L02 (human normal liver cells) as the model, and explored its molecular mechanism. We found that CMEPA (0-160 mg/L) induced apoptosis (similar to 40%), mitochondrial damage and oxidative stress in L02 cells. CMEPA induced intracellular lipid accumulation by inhibiting AMPK/ACC/CPT-1A signaling pathway and activating SREBP-1c/FAS signaling pathway. Our study provides evidence of a link between CMEPA and liver injury. This raises concerns regarding the health risks of pesticide metabolites to liver health.

ROS-mediated PPAR/RXR inhibition contributes to acetochlor-induced apoptosis and autophagy in Ctenopharyngodon idella hepatic cells

Acetochlor is a high-volume herbicide whose widespread use threatens ecosystems and affects aquaculture. Apoptosis and autophagy are important causes of hepatotoxicity caused by toxicants, which can be mediated by oxidative stress and the inhibition of PPAR/RXR pathway. However, the mechanism of acetochlor on fish hepatocyte damage still needs to be further investigated. Therefore, we treated the Ctenopharyngodon idella hepatic cell line (L8824 cells) with different concentrations (10, 20, and 40 μM) of acetochlor and/or ROS scavenger NAC (1 mM) for 24 h. The results showed that acetochlor decreased the cell viability in a dose-dependent manner. AO/EB staining and flow cytometry verified the increased apoptotic rates. Quantitative analysis of gene expression levels or protein expression levels displayed that the expression levels of Beclin1, P62, LC3B, BAX, and cleaved Casp3 were increased, and the expression of BCL2 was reduced. Besides, we detected the increased ROS contents and decreased PPAR/RXR pathway expressions after acetochlor treatment. The clearance of ROS alleviated the inhibition of the PPAR/RXR pathway and lightened apoptosis and autophagy under acetochlor stress. Overall, these results revealed that acetochlor exposure triggered BCL2/BAX/Casp3-cascaded apoptosis and Beclin1-dependent autophagy through ROS-mediated PPAR/RXR inhibition. The results partially explain the toxicological mechanism of acetochlor and provide targets for the development of its antidote.

Effect of DEHP and DnOP on mitochondrial damage and related pathways of Nrf2 and SIRT1/PGC-1α in HepG2 cells

Di-2-ethylhexyl phthalate (DEHP) and Dioctyl phthalate (DnOP) are widely used as plasticizers in various industries for which the consequent health problems are of great concern. In this context, we treated HepG2 cells with DEHP or DnOP for 48 h. The results showed that DEHP and DnOP caused increase in oxygen species (ROS), malondialdehyde (MDA), Alanine aminotransferase (ALT) and Aspartate transaminase (AST). The proteins NF⁃E2-related factor 2 (Nrf2) and haemeoxygenase-1 (HO-1), were significantly down-regulated. Subsequently, the mitochondrial structure was disrupted, and the ATP content, the mitochondrial copy number as well as the expression of the corresponding mitochondrial genes were also reduced. The expression of sirtuin 1(SIRT1), PPAR gamma co-activator 1 alpha (PGC-1α), Nuclear respiratory factor 1(Nrf1), Mitochondrial transcription factor A (TFAM) on the SIRT1/PGC-1α pathway were significantly reduced. Finally, neither DEHP nor DnOP was found to induce apoptosis, but could significantly up-regulate Light chain 3 II (LC3II) levels. In conclusion, DEHP and DnOP could induce HepG2 cell damage via mitochondria, probably by causing oxidative stress, inhibiting the Nrf2 pathway and inhibiting the mitochondrial biogenesis pathway, which leads to excessive autophagy and cell death. DEHP and DnOP differ in the Nrf2 pathway, autophagic pathway and MAPK pathway, which may be structurally related.

DMEP induces mitochondrial damage regulated by inhibiting Nrf2 and SIRT1/PGC-1α signaling pathways in HepG2 cells

Dimethoxyethyl phthalate (DMEP) is an environmental endocrine disruptor. However, research into the underlying mechanisms of DMEP mitochondrial toxicity is still in its infancy. We therefore expect to understand whether DMEP induced mitochondrial damage in HepG2 cells and the associated signaling pathways. DMEP (0.125, 0.25, 0.5, 1 and 2 mM) exposure for 48 h induced a notable increment in reactive oxygen species (ROS), malondialdehyde (MDA), alanine aminotransferase (ALT), aspartate transaminase (AST) and 8-hydroxydeoxyguanosine (8-OHdG) in hepG2 cells, resulting in cellular oxidative stress. Low doses of DMEP upregulated nuclear factor E2-related factor 2 (Nrf2) and downstream protein haeme oxygenase-1 (HO-1) levels and high doses down-regulated their levels. Nrf2 levels increased after ROS scavenging by N-acetyl-L-cysteine (NAC), which indicated that the Nrf2 pathway may be affected by oxidative stress. We also found that DMEP decreased ATP content, mitochondrial copy number (mtDNA), translocase of the outer membrane subunit 20 (TOM20) expression, mitochondria-encoded genes CO1, CO2, CO3, ATP6, ATP8 expression, inhibited mitochondrial biogenesis pathway, down-regulated sirtuin 1(SIRT1), PPAR gamma co-activator 1 alpha (PGC-1α), Nuclear respiratory factor 1(Nrf1), Mitochondrial transcription factor A (TFAM) content and activated PINK1/Parkin autophagy pathway. DMEP also activated the mitochondrial apoptotic pathway, causing cytochrome c cytoplasmic translocation and caspase 3 cleavage. What's more, DMEP activated the Nuclear factor-κB (NF-κB) pathway and levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were significantly upregulated, causing an inflammatory response. In summary, DMEP can cause inflammatory response and oxidative stress in HepG2 cells, inhibited the Nrf2 pathway and mitochondrial biogenesis, and induced autophagy and apoptosis. And oxidative stress at least partially affected the Nrf2 pathway and mitochondrial biogenesis SIRT1/PGC-1α pathway.