The food-borne carcinogenic 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) disrupts circadian rhythms and ameliorated by pterostilbene (PSB) in Caenorhabditis elegans.

The food-borne 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a potential human carcinogen abundant in cooked meat. While circadian rhythms are crucial biological oscillations, the negative impact of PhIP on circadian systems and the potential of mitigation remain underexplored. We investigated the effects of PhIP on circadian rhythms and the mitigating effects of the phytochemical antioxidant pterostilbene (PSB) in Caenorhabditis elegans. We show that exposure to 10 µM PhIP disrupts the 24-h circadian rhythms of C. elegans, an effect mitigated by co-exposure to 100 µM PSB. In addition, PhIP-induced circadian disruption can be linked to defective oxidative stress resistance, which is associated with the DAF-16/FOXO pathway and is modulated by PSB. Molecular docking suggested that PhIP and PSB bind similarly to DAF-16. Moreover, 10 µM PhIP abolished the rhythmic expression of the core clock gene prdx-2, which is restored by 100 µM PSB. Findings from this study provide novel insight of how food-borne contaminant like PhIP may contribute to the disruption of circadian rhythms and suggest potential for PSB to mitigate these effects in higher organisms.

Distinct neurodevelopmental and epileptic phenotypes associated with gain- and loss-of-function GABRB2 variants.

BACKGROUND: Variants in GABRB2, encoding the ß2 subunit of the γ-aminobutyric acid type A (GABAA) receptor, can result in a diverse range of conditions, ranging from febrile seizures to severe developmental and epileptic encephalopathies. However, the mechanisms underlying the risk of developing milder vs more severe forms of disorder remain unclear. In this study, we conducted a comprehensive genotype-phenotype correlation analysis in a cohort of individuals with GABRB2 variants. METHODS: Genetic and electroclinical data of 42 individuals harbouring 26 different GABRB2 variants were collected and accompanied by electrophysiological analysis of the effects of the variants on receptor function. FINDINGS: Electrophysiological assessments of α1ß2γ2 receptors revealed that 25/26 variants caused dysfunction to core receptor properties such as GABA sensitivity. Of these, 17 resulted in gain-of-function (GOF) while eight yielded loss-of-function traits (LOF). Genotype-phenotype correlation analysis revealed that individuals harbouring GOF variants suffered from severe developmental delay/intellectual disability (DD/ID, 74%), movement disorders such as dystonia or dyskinesia (59%), microcephaly (50%) and high risk of early mortality (26%). Conversely, LOF variants were associated with milder disease manifestations. Individuals with these variants typically exhibited fever-triggered seizures (92%), milder degrees of DD/ID (85%), and maintained ambulatory function (85%). Notably, severe movement disorders or microcephaly were not reported in individuals with loss-of-function variants. INTERPRETATION: The data reveals that genetic variants in GABRB2 can lead to both gain and loss-of-function, and this divergence is correlated with distinct disease manifestations. Utilising this information, we constructed a diagnostic flowchart that aids in predicting the pathogenicity of recently identified variants by considering clinical phenotypes. FUNDING: This work was funded by the Australian National Health & Medical Research Council, the Novo Nordisk Foundation and The Lundbeck Foundation.

Life cycle exposure to titanium dioxide nanoparticles (TiO2-NPs) induces filial toxicity and population decline in the nematode Caenorhabditis elegans.

Titanium dioxide nanoparticle (TiO2-NP) exposure has raised significant concern due to their potential toxicity and adverse ecological impacts. Despite their ubiquitous presence in various environmental compartments, the long-term consequences of TiO2-NPs remain poorly understood. In this study, we combined data of in vivo toxicity and modeling to investigate the potential negative impacts of TiO2-NP exposure. We employed the nematode Caenorhabditis elegans, an environmental organism, to conduct a full life cycle TiO2-NP toxicity assays. Moreover, to assess the potential impact of TiO2-NP toxicity on population dynamics, we applied a stage-constructed matrix population model (MPM). Results showed that TiO2-NPs caused significant reductions in reproduction, survival, and growth of parental C. elegans (P0) at the examined concentrations. Moreover, these toxic effects were even more pronounced in the subsequent generation (F1) when exposed to TiO2-NPs. Furthermore, parental TiO2-NP exposure resulted in significant toxicity in non-exposed C. elegans progeny (TiO2-NPs free), adversely affecting their reproduction, survival, and growth. MPM analysis revealed decreased transition probabilities of surviving (Pi), growth (Gi), and fertility (Fi) in scenarios with TiO2-NP exposure. Additionally, the population growth rate (λmax) was found to be less than 1 in both P0 and F1, indicating a declining population trend after successive generations. Sensitivity analysis pinpointed L1 larvae as the most vulnerable stage, significantly contributing to the observed population decline in both P0 and F1 generations under TiO2-NP exposure. Our findings provide insight into the potential risk of an environmental organism like nematode by life cycle exposure to TiO2-NPs.

Correlations of receptor desensitization of gain-of-function GABRB3 variants with clinical severity.

Genetic variants associated with developmental and epileptic encephalopathies have been identified in the GABRB3 gene that encodes the ß3 subunit of GABAA receptors. Typically, variants alter receptor sensitivity to GABA resulting in either gain- or loss-of-function, which correlates with patient phenotypes. However, it is unclear how another important receptor property, desensitization, contributes to the greater clinical severity of gain-of-function variants. Desensitization properties of 20 gain-of-function GABRB3 variant receptors were evaluated using two-electrode voltage-clamp electrophysiology. The parameters measured included current decay rates and steady-state currents. Selected variants with increased or reduced desensitization were also evaluated using whole-cell electrophysiology in transfected mammalian cell lines. Of the 20 gain-of-function variants assessed, 13 were found to alter receptor desensitization properties. Seven variants reduced desensitization at equilibrium, which acts to worsen gain-of-function traits. Six variants accelerated current decay kinetics, which limits gain-of-function traits. All affected patients displayed severe clinical phenotypes with intellectual disability and difficult-to-treat epilepsy. Nevertheless, variants that reduced desensitization at equilibrium were associated with more severe clinical outcomes. This included younger age of first seizure onset (median 0.5 months), movement disorders (dystonia and dyskinesia), epilepsy of infancy with migrating focal seizures (EIMFS) and risk of early mortality. Variants that accelerated current decay kinetics were associated with slightly milder phenotypes with later seizure onset (median 4 months), unclassifiable developmental and epileptic encephalopathies or Lennox-Gastaut syndrome and no movement disorders. Our study reveals that gain-of-function GABRB3 variants can increase or decrease receptor desensitization properties and that there is a correlation with the degree of disease severity. Variants that reduced the desensitization at equilibrium were clustered in the transmembrane regions that constitute the channel pore and correlated with greater disease severity, while variants that accelerated current decay were clustered in the coupling loops responsible for receptor activation and correlated with lesser severity.

Methanol Extracts from Cirsium japonicum DC. var. australe Kitam. and Their Active Components Reduce Intracellular Oxidative Stress in Caenorhabditis elegans.

Cirsium japonicum DC. var. australe Kitam. has been used as an herbal remedy and often involves using the whole plant or roots. However, the bioactivities of different parts of the plant have been far less explored. This study aimed to evaluate the antioxidative ability of methanol extracts from the flowers, leaves, stems, and roots of the Cirsium plant and their possible active components against juglone-induced oxidative stress in the nematode Caenorhabditis elegans. The results showed that the highest dry weight (12.3 g per plant) was observed in leaves, which was followed by stems (8.0 g). The methanol extract yields from the flowers, leaves, and roots were all similar (13.0-13.8%), while the yield from stems was the lowest (8.6%). The analysis of the silymarin contents in the extracts indicated that the flowers, leaves, stems, and roots contained silychristin and taxifolin; however, silydianin was only found in the leaves, stems, and roots. The flower, leaf, and stem extracts, at a concentration of 10 mg/L, significantly reduced juglone-induced oxidative stress in C. elegans, which was potentially due to the presence of silychristin and taxifolin. Overall, C. japonicum DC. var. australe Kitam. contains a significant amount of silymarin and exhibits in vivo antioxidative activity, suggesting that the prospects for the plant in terms of health supplements or as a source of silymarin are promising.

GABAA receptors in epilepsy: Elucidating phenotypic divergence through functional analysis of genetic variants.

Normal brain function requires a tightly regulated balance between excitatory and inhibitory neurotransmissions. γ-Aminobutyric acid type A (GABAA ) receptors represent the major class of inhibitory ion channels in the mammalian brain. Dysregulation of these receptors and/or their associated pathways is strongly implicated in the pathophysiology of epilepsy. To date, hundreds of different GABAA receptor subunit variants have been associated with epilepsy, making them a prominent cause of genetically linked epilepsy. While identifying these genetic variants is crucial for accurate diagnosis and effective genetic counselling, it does not necessarily lead to improved personalised treatment options. This is because the identification of a variant does not reveal how the function of GABAA receptors is affected. Genetic variants in GABAA receptor subunits can cause complex changes to receptor properties resulting in various degrees of gain-of-function, loss-of-function or a combination of both. Understanding how variants affect the function of GABAA receptors therefore represents an important first step in the ongoing development of precision therapies. Furthermore, it is important to ensure that functional data are produced using methodologies that allow genetic variants to be classified using clinical guidelines such as those developed by the American College of Medical Genetics and Genomics. This article will review the current knowledge in the field and provide recommendations for future functional analysis of genetic GABAA receptor variants.

GABRA1-Related Disorders: From Genetic to Functional Pathways.

OBJECTIVE: Variants in GABRA1 have been associated with a broad epilepsy spectrum, ranging from genetic generalized epilepsies to developmental and epileptic encephalopathies. However, our understanding of what determines the phenotype severity and best treatment options remains inadequate. We therefore aimed to analyze the electroclinical features and the functional effects of GABRA1 variants to establish genotype-phenotype correlations. METHODS: Genetic and electroclinical data of 27 individuals (22 unrelated and 2 families) harboring 20 different GABRA1 variants were collected and accompanied by functional analysis of 19 variants. RESULTS: Individuals in this cohort could be assigned into different clinical subgroups based on the functional effect of their variant and its structural position within the GABRA1 subunit. A homogenous phenotype with mild cognitive impairment and infantile onset epilepsy (focal seizures, fever sensitivity, and electroencephalographic posterior epileptiform discharges) was described for variants in the extracellular domain and the small transmembrane loops. These variants displayed loss-of-function (LoF) effects, and the patients generally had a favorable outcome. A more severe phenotype was associated with variants in the pore-forming transmembrane helices. These variants displayed either gain-of-function (GoF) or LoF effects. GoF variants were associated with severe early onset neurodevelopmental disorders, including early infantile developmental and epileptic encephalopathy. INTERPRETATION: Our data expand the genetic and phenotypic spectrum of GABRA1 epilepsies and permit delineation of specific subphenotypes for LoF and GoF variants, through the heterogeneity of phenotypes and variants. Generally, variants in the transmembrane helices cause more severe phenotypes, in particular GoF variants. These findings establish the basis for a better understanding of the pathomechanism and a precision medicine approach in GABRA1-related disorders. Further studies in larger populations are needed to provide a conclusive genotype-phenotype correlation. ANN NEUROL 2023.

Vinpocetine improved neuropsychiatric and epileptic outcomes in a patient with a GABRA1 loss-of-function variant.

Vinpocetine is a synthetic derivative of the alkaloid vincamine and has been used as a dietary supplement for decades. Following a positive report of the use of vinpocetine in a patient with a loss-of-function GABRB3 variant, we here describe another patient with a loss-of-function GABRA1 variant (p.(Arg112Gln)) who benefited from vinpocetine treatment. This patient was diagnosed with autism spectrum disorder, psychiatric complications, and therapy-resistant focal epilepsy. Upon add-on treatment with 40 mg vinpocetine daily for 16 months, the patient experienced an overall improved quality of life as well as seizure freedom. Our findings corroborate that vinpocetine can attenuate epilepsy-associated behavioral issues in patients with loss-of-function GABAA receptor gene variants.

Nanoplastics exposure disrupts circadian rhythm associated with dysfunction of the endolysosomal pathway and autophagy in Caenorhabditis elegans.

Nanoplastics (NPs), an emerging pollutant, have raised great safety concerns due to their widespread applications and continuous release into the environment, which lead to potential human and environmental risks. Recently, polystyrene NPs (100 nm; 100 mg/L) exposure has been reported to disrupt circadian rhythms under five days temperature entrainment and be associated with stress resistance decline in Caenorhabditis elegans. This study explored the possible relationship between circadian rhythm disruption and endocytosis and autophagy under polystyrene NPs exposure in C. elegans. We show that the disrupted circadian rhythm induced by NPs exposure reduced stress resistance via endocytosis and autophagy impairment. Furthermore, we found that most NPs taken up by intestinal cells were localized to early endosomes, late endosomes, and lysosomes and delivered to autophagosomes. In addition, the disruption of circadian rhythm inhibited NPs localization to these organelles. These findings indicate that NPs exposure disrupts circadian rhythm and alters its subcellular trafficking, leading to enhanced toxicity in C. elegans. Our results shed light on the prominent role of NPs exposure in circadian rhythm disruption associated with endocytosis and autophagy impairments, which may be conserved in higher animals such as humans.

3,5-bis(styryl)pyrazole inhibits mitosis and induces cell death independent of BubR1 and p53 levels by depolymerizing microtubules.

Here, we show that 3,5-bis[(1E)-2-(2,6-dichlorophenyl)ethenyl]-1H-pyrazole 2l depolymerizes microtubules and reduces the number of growing tips of microtubules. The fluorescence recovery after photobleaching experiment in live MCF-7 cells showed that pyrazole 2l suppresses spindle microtubule dynamics. Further, the compound inhibits chromosome movements, activates the spindle assembly checkpoint and blocks mitosis in MCF-7 cells. Pyrazole 2l treatment induced cell death in a variety of pathways. Pyrazole 2l induces cell death independent of BubR1 and p53 levels of MCF-7 cells upon microtubule depolymerization. Further, pyrazole 2l increases the interaction between NF-κB and microtubules and enhances the nuclear localization of NF-κB at its half-maximal proliferation inhibitory concentration while a high concentration of the compound reduced the nuclear localization of NF-κB. Interestingly, the compound exerted significantly stronger antiproliferative effects in cancerous cells than in non-cancerous cells. The results indicated that pyrazole 2l inhibits mitosis by targeting microtubules, induces several types of cell death stimuli and suggests its potential as a lead in developing anticancer agent.

Nanoparticles in the Environment and Nanotoxicology.

Nanomaterials, including engineered nanoparticles and microplastics/nanoplastics, have attracted increasing concern as they might potentially release into the environment, leading to potential risks to ecosystems [...].

Sulfate-modified nanosized polystyrene impairs memory by inhibiting ionotropic glutamate receptors and the cAMP-response element binding protein (CREB) pathway in Caenorhabditis elegans.

Nanoplastic contamination is an emerging environmental concern worldwide. In particular, sulfate anionic surfactants often appear along with nanosized plastic particles in personal care products, suggesting that sulfate-modified nanosized polystyrene (S-NP) may occur, remain, and spread into the environment. However, whether S-NP adversely affects learning and memory is unknown. In this study, we used a positive butanone training protocol to evaluate the effects of S-NP exposure on short-term associative memory (STAM) and long-term associative memory (LTAM) in Caenorhabditis elegans. We observed that long-term S-NP exposure impairs both STAM and LTAM in C. elegans. We also observed that mutations in the glr-1, nmr-1, acy-1, unc-43, and crh-1 genes eliminated the STAM and LTAM impairment induced by S-NP, and the mRNA levels of these genes were also decreased upon S-NP exposure. These genes encode ionotropic glutamate receptors (iGluRs), cyclic adenosine monophosphate (cAMP)/Ca2+ signaling proteins, and cAMP-response element binding protein (CREB)/CRH-1 signaling proteins. Moreover, S-NP exposure inhibited the expression of the CREB-dependent LTAM genes nid-1, ptr-15, and unc-86. Our findings provide new insights into long-term S-NP exposure and the impairment of STAM and LTAM, which involve the highly conserved iGluRs and CRH-1/CREB signaling pathways.

Co-contaminants of ethinylestradiol and sulfamethoxazole in groundwater exacerbate ecotoxicity and ecological risk and compromise the energy budget of C. elegans.

Ethinylestradiol (EE2) and sulfamethoxazole (SMX) are among pharmaceuticals and personal care products (PPCPs) and regarded as emerging contaminants in groundwater worldwide. However, the ecotoxicity and potential risk of these co-contaminants remain unknown. We investigated the effects of early-life long-term co-exposure to EE2 and SMX in groundwater on life-history traits of Caenorhabditis elegans and determined potential ecological risks in groundwater. L1 larvae of wild-type N2 C. elegans were exposed to measured concentrations of EE2 (0.001, 0.75, 5.1, 11.8 mg/L) or SMX (0.001, 1, 10, 100 mg/L) or co-exposed to EE2 (0.75 mg/L, no observed adverse effect level derived from its reproductive toxicity) and SMX (0.001, 1, 10, 100 mg/L) in groundwater. Growth and reproduction were monitored on days 0 - 6 of the exposure period. Toxicological data were analyzed using DEBtox modeling to determine the physiological modes of action (pMoAs) and the predicted no-effect concentrations (PNECs) to estimate ecological risks posed by EE2 and SMX in global groundwater. Early-life EE2 exposure significantly inhibited the growth and reproduction of C. elegans, with lowest observed adverse effect levels (LOAELs) of 11.8 and 5.1 mg/L, respectively. SMX exposure impaired the reproductive capacity of C. elegans (LOAEL = 0.001 mg/L). Co-exposure to EE2 and SMX exacerbated ecotoxicity (LOAELs of 1 mg/L SMX for growth, and 0.001 mg/L SMX for reproduction). DEBtox modeling showed that the pMoAs were increased growth and reproduction costs for EE2 and increased reproduction costs for SMX. The derived PNEC falls within the range of detected environmental levels of EE2 and SMX in groundwater worldwide. The pMoAs for EE2 and SMX combined were increased growth and reproduction costs, resulting in lower energy threshold values than single exposure. Based on global groundwater contamination data and energy threshold values, we calculated risk quotients for EE2 (0.1 - 123.0), SMX (0.2 - 91.3), and combination of EE2 and SMX (0.4 - 341.1). Our findings found that co-contamination by EE2 and SMX exacerbates toxicity and ecological risk to non-target organisms, suggesting that the ecotoxicity and ecological risk of co-contaminants of pharmaceuticals should be considered to sustainably manage groundwater and aquatic ecosystems.

Chronic exposure to di(2-ethylhexyl) phthalate (DEHP) weakens innate immunity and leads to immunosenescence in C. elegans.

Di(2-ethylhexyl) phthalate (DEHP), a widespread contaminant, has numerous adverse impacts on human health and ecosystems. Chronic DEHP exposure has been found to accelerate aging; however, its potential threat to age-dependent innate immune decline remains unknown. This study aims to evaluate the effects of chronic DEHP exposure on innate immunosenescence in Caenorhabditis elegans. We show that the length of the exposure period significantly impacts DEHP-induced age-related declines, which is linked to immunosenescence and oxidative stress. We found that the DEHP-caused immunosenescence is accompanied with downregulation of an antimicrobial gene lys-7 as well as an enhancement of the nuclear translocation of HLH-30, an orthologue of mammalian transcription factor EB (TFEB). Moreover, DEHP exposure increases the expression of riok-1, a human RIO kinase homolog, which is associated with DEHP-induced HLH-30/TFEB translocation. Our findings suggest that early-life and chronic exposure to DEHP, mostly due to parent compound rather than its metabolite mono(2-ethylhexyl) phthalate (MEHP), may weaken the innate immunity in C. elegans and may enhance susceptibility to infections or promote immunosenescence in aged populations.

Assessing the ecological risk and ecotoxicity of the microbially mediated restoration of heavy metal-contaminated river sediment.

Anthropogenic activities such as mining, smelting industries, and the application of pesticides in agriculture might result in contamination of multiple heavy metals in the environment. Heavy metal contamination of sediment is a serious environmental problem, and thus the remediation of contaminated sediment is a worldwide challenge. Several strategies have been developed for the remediation of contaminated sediment, however the ecological risk and ecotoxicity of the restored sediment have rarely been evaluated. We assessed whether river sediment highly contaminated with heavy metals could be restored using microbial bioleaching followed by evaluating the residual toxicity and ecological risk of the microbially remediated sediment. Sequential extraction revealed that the bioavailable levels of Cu, Ni, and Zn in the contaminated sediment exceeded sediment quality guideline (SQG) thresholds. It was consequently found that acidophilic sulfur-oxidizing Acidicaldus sp. SV5 effectively bioleached Cu, Ni, and Zn from the contaminated sediment, reducing the bioavailable fraction of these elements below SQG thresholds. The ecological risk assessment indicated that SV5-driven remediation significantly reduced the potential ecological risk of the contaminated sediment. The residual ecotoxicity of the microbially remediated sediment was also tested with the soil nematode Caenorhabditis elegans. There was a significant decrease in the body burden of Cu, Ni, and Zn in C. elegans and a reduction in the toxicological effect on survival, growth, and reproduction in the microbially remediated sediment. Our study suggests that a combination of chemical analysis, chemical-based ecological risk assessment, and ecotoxicity tests would be helpful for the development of efficient and eco-friendly strategies for the restoration of contaminated sediment, which could be incorporated into sediment quality management practices.

Nanoplastic exposure in soil compromises the energy budget of the soil nematode C. elegans and decreases reproductive fitness.

Environmental nanoplastics (NPs) can accumulate in soils, posing a potential risk to soil ecosystems. However, the ecotoxicity of NPs for soil organisms has received little research attention. This study investigated whether NP exposure in soil leads to reproductive decline in the soil nematode Caenorhabditis elegans and sought to determine the mechanisms by which it may occur. Wild-type N2 C. elegans L1 larvae were exposed to various concentrations of nano-sized polystyrene (100 nm) in soil (0, 1, 10, 100, and 1000 mg/kg dry weight) for 96 h. We show that nano-sized polystyrene (100 nm) labeled with red fluorescence significantly accumulated in the intestine of C. elegans in a dose-dependent fashion via soil exposure (8%-47% increase). In addition, NP soil exposure led to 7%-33% decline in the number of eggs in utero and 2.6%-4.4% decline in the egg hatching percentage. We also find that the number of germ cell corpses (31%-55% increase) and the mRNA levels of germline apoptosis marker gene ced-3 (14%-31% increase) were significantly higher with greater NP soil exposure (10, 100, and 1000 mg/kg), while intracellular ATP levels were significantly reduced. Finally, the DEBtox model, which is based on the dynamic energy budget theory, was applied to show that the increased reproductive costs for C. elegans caused by NPs in soil are associated with energy depletion and reproductive decline. The threshold value (4.18 × 10-6 mg/kg) for the energy budget also highlighted the potential high reproductive risk posed by NPs in terrestrial ecosystems. Our study provides new insights into how soil organisms interact with NPs in soil ecosystems.

Chronic di(2-ethylhexyl) phthalate exposure leads to dopaminergic neuron degeneration through mitochondrial dysfunction in C. elegans.

The plasticizer di(2-ethylhexyl) phthalate (DEHP) is frequently detected in the environment due to the abundance of its use. These levels might be hazardous to human health and ecosystems. Phthalates have been associated with neurological disorders, yet whether chronic DEHP exposure plays a role in Parkinson's disease (PD) or its underlying mechanisms is unknown. We investigated the effects of chronic DEHP exposure less than an environmentally-relevant dose on PD hallmarks, using Caenorhabditis elegans as a model. We show that developmental stage and exposure timing influence DEHP-induced dopaminergic neuron degeneration. In addition, in response to chronic DEHP exposure at 5 mg/L, mitochondrial fragmentation became significantly elevated, reactive oxygen species (ROS) levels increased, and ATP levels decreased, suggesting that mitochondrial dysfunction occurs. Furthermore, the data show that mitochondrial complex I (nuo-1 and gas-1) and complex II (mev-1) are involved in DEHP-induced dopaminergic neuron toxicity. These results suggest that chronic exposure to DEHP at levels less than an environmentally-relevant dose causes dopaminergic neuron degeneration through mitochondrial dysfunction involving mitochondrial complex I and II. Considering the high level of genetic conservation between C. elegans and mammals, chronic DEHP exposure might elevate the risk of developing PD in humans.

Chronic exposure to environmentally relevant levels of di(2-ethylhexyl) phthalate (DEHP) disrupts lipid metabolism associated with SBP-1/SREBP and ER stress in C. elegans.

DEHP is commonly found in the environment, biota, food, and humans, raising significant health concerns. Whether developmental stage and exposure duration modify the obesogenic effects of DEHP is unclear, especially the underlying mechanisms by which chronic exposure to DEHP as well as its metabolites remain largely unknown. This study investigated the obesogenic effects of chronic DEHP exposure, with levels below environmentally-relevant amounts and provide the mechanism in Caenorhabditis elegans. We show that early-life DEHP exposure resulted in an increased lipid and triglyceride (TG) accumulation mainly attributed to DEHP itself, not its metabolite mono-2-ethylhexyl phthalate (MEHP). In addition, developmental stage and exposure timing influence DEHP-induced TG accumulation and chronic DEHP exposure resulted in the most significant effect. Analysis of fatty acid composition shows that chronic DEHP exposure altered fatty acid composition and TG, resulting in an increased ω-6/ω-3 ratio. The increased TG content by chronic DEHP exposure required lipogenic genes fat-6, fat-7, pod-2, fasn-1, and sbp-1. Moreover, chronic DEHP exposure induced XBP-1-mediated endoplasmic reticulum (ER) stress which might lead to up-regulation of sbp-1. This study suggests the possible involvement of ER stress and SBP-1/SREBP-mediated lipogenesis in chronic DEHP-induced obesogenic effects. Results from this study implies that chronic exposure to DEHP disrupts lipid metabolism, which is likely conserved across species due to evolutionary conservation of molecular mechanisms, raising concerns in ecological and human health.

Potential anti-Parkinsonian's effect of S-(+)-linalool from Cinnamomum osmophloeum ct. linalool leaves are associated with mitochondrial regulation via gas-1, nuo-1, and mev-1 in Caenorhabditis elegans.

Parkinson's disease (PD) is one of the prevalent neurodegenerative diseases, and developing new treatments from natural products is of particular interest. Essential oils from Cinnamomum osmophloeum ct. linalool leaves contain high levels (~95%) of S-(+)-linalool. The neuroprotective effects of linalool have been previously described, yet the underlying molecular mechanisms remain largely unknown. This study aimed to investigate the potential anti-Parkinsonian's effect of S-(+)-linalool on mitochondrial regulation and decipher the underlying molecular mechanisms in Caenorhabditis elegans PD model. Essential oils at 20 mg/L and 20 mg/L S-(+)-linalool each significantly attenuated the damaging effects of 6-hydroxydopamine (6-OHDA) on dopaminergic (DA) neurons and decreased the mitochondrial unfolded protein response (UPRmt ) to antimycin. RNAi knockdown of mitochondrial complex I (gas-1, nuo-1), and complex II (mev-1) genes prevented the improvement of mitochondrial activity by S-(+)-linalool. The protective effects of S-(+)-linalool on 6-OHDA-induced behavior changes were absent in a DA-specific strain of C. elegans produced by gas-1, nuo-1, and mev-1 RNAi knockdown. These results suggest the potential anti-Parkinsonian's effect of S-(+)-linalool is associated with mitochondrial activity and regulated by gas-1, nuo-1, and mev-1 in C. elegans. Our findings suggest that S-(+)-linalool might be a promising candidate for therapeutic application to inhibit the progression of PD.