Mono-2-ethylhexyl phthalate drives progression of PINK1-parkin-mediated mitophagy via increasing mitochondrial ROS to exacerbate cytotoxicity

Low-cost and sensitive chemiluminescence detection of phthalates in environment by signal sensing of carbon-based materials from PVC/coal gangue dechlorination

BACKGROUND

The detection of plasticizers in the environment is important to prevent environmental risks and people's health hazards. Improving recycling efficiency of waste PVC still faced challenges.

RESULTS

In this work, it was found that solid products from waste PVC/coal gangue dechlorination in subcritical water (dPVC) had strong catalysis activity for luminol-H2O2 chemiluminescence (CL) reaction. Phthalates, common plasticizers, could bond and adsorb on dPVC, which greatly inhibited the luminol-H2O2-dPVC CL reaction. Based on this, a low-cost CL analysis was constructed for the detection of phthalates combinations (PACs) and di-(2-ethylhexyl) phthalate (DEHP) in the environment. The detection limit for PACs and DEHP was 0.048 ng/L and 0.13 ng/L, respectively. Compared with HPLC standard method, the dPVC CL analysis had accuracy and reliability for the detection of phthalates in actual environmental samples. Besides, the results of life cycle assessment (LCA) revealed that dPVC for CL sensing materials had significantly small global warming potential (GWP).

SIGNIFICANCE

The use of dPVC for CL sensing not only improved the recycling efficiency of PVC, but also reduced carbon emissions of obtaining CL sensing materials.

Macrophage migration inhibitory factor (MIF) suppresses mitophagy through disturbing the protein interaction of PINK1-Parkin in sepsis-associated acute kidney injury

Damage to renal tubular epithelial cells (RTECs) signaled the onset and progression of sepsis-associated acute kidney injury (SA-AKI). Recent research on mitochondria has revealed that mitophagy plays a crucial physiological role in alleviating injury to RTECs and it is suppressed progressively by the inflammation response in SA-AKI. However, the mechanism by which inflammation influences mitophagy remains poorly understood. We examined how macrophage migration inhibitory factor (MIF), a pro-inflammatory protein, influences the PINK1-Parkin pathway of mitophagy by studying protein-protein interactions when MIF was inhibited or overexpressed. Surprisingly, elevated levels of MIF were found to directly bind to PINK1, disrupting its interaction with Parkin. This interference hindered the recruitment of Parkin to mitochondria and impeded the initiation of mitophagy. Furthermore, this outcome led to significant apoptosis of RTECs, which could, however, be reversed by an MIF inhibitor ISO-1 and/or a new mitophagy activator T0467. These findings highlight the detrimental impact of MIF on renal damage through its disruption of the interaction between PINK1 and Parkin, and the therapeutic potential of ISO-1 and T0467 in mitigating SA-AKI. This study offers a fresh perspective on treating SA-AKI by targeting MIF and mitophagy.

Mitophagy in relation to chronic inflammation/ROS in aging

Various assaults on mitochondria occur during the human aging process, contributing to mitochondrial dysfunction. This mitochondrial dysfunction is intricately connected with aging and diseases associated with it. In vivo, the accumulation of defective mitochondria can precipitate inflammatory and oxidative stress, thereby accelerating aging. Mitophagy, an essential selective autophagy process, plays a crucial role in managing mitochondrial quality control and homeostasis. It is a highly specialized mechanism that systematically removes damaged or impaired mitochondria from cells, ensuring their optimal functioning and survival. By engaging in mitophagy, cells are able to maintain a balanced and stable environment, free from the potentially harmful effects of dysfunctional mitochondria. An ever-growing body of research highlights the significance of mitophagy in both aging and age-related diseases. Nonetheless, the association between mitophagy and inflammation or oxidative stress induced by mitochondrial dysfunction remains ambiguous. We review the fundamental mechanisms of mitophagy in this paper, delve into its relationship with age-related stress, and propose suggestions for future research directions.

Effect of MEHP on testosterone synthesis via Sirt1/Foxo1/Rab7 signaling pathway inhibition of lipophagy in TM3 cells

Mono-2-ethylhexyl phthalic acid (MEHP) is the most toxic metabolite of the plasticizer di-2-ethylhexyl phthalic acid (DEHP), and studies have shown that MEHP causes serious reproductive effects. However, its exact mechanisms of action remain elusive. In this study, we aimed to investigate the reproductive effects of MEHP and preliminarily explore its underlying molecular mechanisms. We found that TM3 cells gradually secreted less testosterone and intracellular free cholesterol with increasing MEHP exposure. MEHP exposure inhibited lipophagy and the Sirt1/Foxo1/Rab7 signaling pathway in TM3 cells, causing aberrant accumulation of intracellular lipid droplets. Addition of the Sirt1 agonist SRT1720 and Rab7 agonist ML-098 alleviated the inhibition of lipophagy and increased free cholesterol and testosterone contents in TM3 cells. SRT1720 alleviated the inhibitory effect of MEHP on the Sirt1/Foxo1/Rab7 signaling pathway, whereas ML-098 only alleviated the inhibition of Rab7 protein expression by MEHP and had no effect on Sirt1 and Foxo1 protein expression. This suggests that MEHP inhibits lipophagy in TM3 cells by suppressing the Sirt1/Foxo1/Rab7 signaling pathway, ultimately leading to a further decrease in cellular testosterone secretion. This study improves our current understanding of the toxicity and molecular mechanisms of action of MEHP and provides new insights into the reproductive effects of phthalic acid esters.

Reactive Oxygen Species-Mediated Mitophagy and Cell Apoptosis are Involved in the Toxicity of Aluminum Chloride Exposure in GC-2spd

Aluminum chloride is an inorganic polymeric coagulant commonly found in daily life and various materials. Although male reproductive toxicity has been associated with AlCl3 exposure, the underlying mechanism remains unclear. This study aimed to examine the impact of AlCl3 exposure on mitophagy and mitochondrial apoptosis in testicular tissue and mouse spermatocytes. Reactive oxygen species (ROS) and ATP levels were measured in GC-2spd after AlCl3 exposure using a multifunctional enzyme labeler. The changes in mitochondrial membrane potential (MMP) and TUNEL were observed through confocal laser microscopy, and the expression of proteins associated with mitophagy and apoptosis was analyzed using Western blot. Our results demonstrated that AlCl3 exposure disrupted mitophagy and increased apoptosis-related protein expression in testicular tissues. In the in vitro experiments, AlCl3 exposure induced ROS production, suppressed cell viability and ATP production, and caused a decrease in MMP, leading to mitophagy and cell apoptosis in GC-2spd cells. Intervention with N-acetylcysteine (NAC) reduced ROS production and partially restored mitochondrial function, thereby reversing the resulting mitophagy and cell apoptosis. Our findings provide evidence that ROS-mediated mitophagy and cell apoptosis play a crucial role in the toxicity of AlCl3 exposure in GC-2spd. These results contribute to the understanding of male reproductive toxicity caused by AlCl3 exposure and offer a foundation for future research in this area.

SLC7A11 as a therapeutic target to attenuate phthalates-driven testosterone level decline in mice

INTRODUCTION

Phthalates exposure is a major public health concern due to the accumulation in the environment and associated with levels of testosterone reduction, leading to adverse pregnancy outcomes. However, the relationship between phthalate-induced testosterone level decline and ferroptosis remains poorly defined.

OBJECTIVES

Herein, we aimed to explore the mechanisms of phthalates-induced testosterone synthesis disorder and its relationship to ferroptosis.

METHODS

We conducted validated experiments in vivo male mice model and in vitro mouse Leydig TM3 cell line, followed by RNA sequencing and metabolomic analysis. We evaluated the levels of testosterone synthesis-associated enzymes and ferroptosis-related indicators by using qRT-PCR and Western blotting. Then, we analyzed the lipid peroxidation, ROS, Fe2+ levels and glutathione system to confirm the occurrence of ferroptosis.

RESULTS

In the present study, we used di (2-ethylhexyl) phthalate (DEHP) to identify ferroptosis as the critical contributor to phthalate-induced testosterone level decline. It was demonstrated that DEHP caused glutathione metabolism and steroid synthesis disorders in Leydig cells. As the primary metabolite of DEHP, mono-2-ethylhexyl phthalate (MEHP) triggered testosterone synthesis disorder accompanied by a decrease in the expression of solute carri1er family 7 member 11 (SLC7A11) protein. Furthermore, MEHP synergistically induced ferroptosis with Erastin through the increase of intracellular and mitochondrial ROS, and lipid peroxidation production. Mechanistically, overexpression of SLC7A11 counteracts the synergistic effect of co-exposure to MEHP-Erastin.

CONCLUSION

Our research results suggest that MEHP does not induce ferroptosis but synergizes Erastin-induced ferroptosis. These findings provide evidence for the role of ferroptosis in phthalates-induced testosterone synthesis disorder and point to SLC7A11 as a potential target for male reproductive diseases. This study established a correlation between ferroptosis and phthalates cytotoxicity, providing a novel view point for mitigating the issue of male reproductive disease and "The Global Plastic Toxicity Debt".

Hepatotoxic effects of chronic exposure to environmentally relevant concentrations of Di-(2-ethylhexyl) phthalate (DEHP) on crucian carp: Insights from multi-omics analyses

Di-(2-ethylhexyl) phthalate (DEHP) is an extensively used phthalate esters (PAEs) that raise growing ecotoxicological concerns due to detrimental effects on living organisms and ecosystems. This study performed hepatotoxic investigations on crucian carp under chronic low-dosage (CLD) exposure to DEHP at environmentally relevant concentrations (20-500 μg/L). The results demonstrated that the CLD exposure induced irreversible damage to the liver tissue. Multi-omics (transcriptomics and metabolomics) analyses revealed the predominant toxicological mechanisms underlying DEHP-induced hepatotoxicity by inhibiting energy production pathways and the up-regulation of the purine metabolism. Disruption of metabolic pathways led to excessive reactive oxygen species (ROS) production and subsequent oxidative stress. The adverse metabolic effects were exacerbated by an interplay between oxidative stress and endoplasmic reticulum stress. This study not only provides new mechanistic insights into the ecotoxicological effects of DEHP under chronic low-dosage exposure, but also suggests a potential strategy for further ecological risk assessment of PAEs.

The mitochondrial link: Phthalate exposure and cardiovascular disease

Phthalates' pervasive presence in everyday life poses concern as they have been revealed to induce perturbing health defects. Utilized as a plasticizer, phthalates are riddled throughout many common consumer products including personal care products, food packaging, home furnishings, and medical supplies. Phthalates permeate into the environment by leaching out of these products which can subsequently be taken up by the human body. It is previously established that a connection exists between phthalate exposure and cardiovascular disease (CVD) development; however, the specific mitochondrial link in this scenario has not yet been described. Prior studies have indicated that one possible mechanism for how phthalates exert their effects is through mitochondrial dysfunction. By disturbing mitochondrial structure, function, and signaling, phthalates can contribute to the development of the foremost cause of death worldwide, CVD. This review will examine the potential link among phthalates and their effects on the mitochondria, permissive of CVD development.

SIRT3 alleviates painful diabetic neuropathy by mediating the FoxO3a-PINK1-Parkin signaling pathway to activate mitophagy

INTRODUCTION

Painful diabetic neuropathy (PDN) is a common complication of diabetes. Previous studies have implicated that mitochondrial dysfunction plays a role in the development of PDN, but its pathogenesis and mechanism have not been fully investigated.

METHODS

In this study, we used high-fat diet/low-dose streptozotocin-induced rats as a model of type 2 diabetes mellitus. Behavioral testing, whole-cell patch-clamp recordings of dorsal root ganglion (DRG) neurons, and complex sensory nerve conduction velocity studies were used to assess peripheral neuropathy. Mitochondrial membrane potential (MMP), ATP, tissue reactive oxygen species, and transmission electron microscopy were used to evaluate the function and morphology of mitochondria in DRG. Real-time PCR, western blot, and immunofluorescence were performed to investigate the mechanism.

RESULTS

We found that damaged mitochondria were accumulated and mitophagy was inhibited in PDN rats. The expression of sirtuin 3 (SIRT3), which is an NAD+-dependent deacetylase in mitochondria, was inhibited. Overexpression of SIRT3 in DRG neurons by intrathecally administered LV-SIRT3 lentivirus ameliorated neurological and mitochondrial dysfunctions. This was evidenced by the reversal of allodynia and nociceptor hyperexcitability, as well as the restoration of MMP and ATP levels. Overexpression of SIRT3 restored the inhibited mitophagy by activating the FoxO3a-PINK1-Parkin signaling pathway. The effects of SIRT3 overexpression, including the reversal of allodynia and nociceptor hyperexcitability, the improvement of impaired mitochondria and mitophagy, and the restoration of PINK1 and Parkin expression, were counteracted when FoxO3a siRNA was intrathecally injected.

CONCLUSION

These results showed that SIRT3 overexpression ameliorates PDN via activation of FoxO3a-PINK1-Parkin-mediated mitophagy, suggesting that SIRT3 may become an encouraging therapeutic strategy for PDN.

Di-(2-ethylhexyl) phthalate exposure induces premature testicular senescence by disrupting mitochondrial respiratory chain through STAT5B-mitoSTAT3 in Leydig cell

Di-(2-ethylhexyl) phthalate (DEHP), a prevalent plasticizer, is known to have endocrine-disrupting effects on males and cause reproductive toxicity. There were causal effects of DEHP on testosterone levels in the real world by Mendelian randomization analysis. Exposure to DEHP during the preadult stage might lead to premature testicular senescence, but the mechanisms responsible for this have yet to be determined. In this study, we administered DEHP (300 mg/kg/day) to male C57BL/6 mice from postnatal days 21 to 49. The mice were kept for 6 months without DEHP. RNA sequencing was conducted on testicular tissue at PNM6. The results indicated that DEHP hindered testicular development, lowered serum testosterone levels in male mice, and induced premature testicular senescence. TM3 Leydig cells were exposed to 300 μM of mono(2-ethylhexyl) phthalate (MEHP), the bioactive metabolite of DEHP, for 72 h. The results also found that DEHP/MEHP induced senescence in vivo and in vitro. The mitochondrial respiratory chain was disrupted in Leydig cells. The expression and stability of STAT5B were elevated by MEHP treatment in TM3 cells. Furthermore, p-ERK1/2 was significantly decreased by STAT5B, and mitochondria-STAT3 (p-STAT3 ser727) was significantly decreased due to the decrease of p-ERK1/2. Additionally, the senescence level of TM3 cells was decreased and treated with 5 mM NAC for 1 h after MEHP treatment. In conclusion, these findings provided a novel mechanistic understanding of Leydig cells by disrupting the mitochondrial respiratory chain through STAT5B-mitoSTAT3.

X-box binding protein 1 caused an imbalance in pyroptosis and mitophagy in immature rats with di-(2-ethylhexyl) phthalate-induced testis toxicity

As a widely used plasticizer, di-(2-ethylhexyl) phthalate (DEHP) is known to induce significant testicular injury. However, the potential mechanism and effects of pubertal exposure to DEHP on testis development remain unclear. In vivo, postnatal day (PND) 21 male rats were gavaged with 0, 250, and 500 mg/kg DEHP for ten days. Damage to the seminiferous epithelium and disturbed spermatogenesis were observed after DEHP exposure. Meanwhile, oxidative stress-induced injury and pyroptosis were activated. Both endoplasmic reticulum (ER) stress and mitophagy were involved in this process. Monoethylhexyl phthalate (MEHP) was used as the biometabolite of DEHP in vitro. The GC-1 and GC-2 cell lines were exposed to 0, 100 μM, 200 μM, and 400 μM MEHP for 24 h. Reactive oxygen species (ROS) generation, oxidative stress damage, ER stress, mitophagy, and pyroptosis were significantly increased after MEHP exposure. The ultrastructure of the ER and mitochondria was destroyed. X-box binding protein 1 (XBP1) was observed to be activated and translocated into the nucleus. ROS generation was inhibited by acetylcysteine. The levels of antioxidative stress, ER stress, mitophagy, and pyroptosis were decreased as well. After the administration of the ER stress inhibitor 4-phenyl-butyric acid, both mitophagy and pyroptosis were inhibited. Toyocamycin-induced XBP1 down-regulation decreased the levels of mitophagy and pyroptosis. The equilibrium between pyroptosis and mitophagy was disturbed by XBP1 accumulation. In summary, our findings confirmed that DEHP induced a ROS-mediated imbalance in pyroptosis and mitophagy in immature rat testes via XBP1. Moreover, XBP1 might be the key target in DEHP-related testis dysfunction.

Characterization and functional analysis of SOCS9 from orange-spotted grouper (Epinephelus coioides) during virus infection

The suppressor of cytokine signaling (SOCS) proteins family have twelve members including eight known mammalian SOCS members (CISH, SOCS1-7) and four new discovery members (SOCS3b, SOCS5b, SOCS8 and SOCS9) that is regarded as a classic feedback inhibitor of cytokine signaling. Although the function of the mammalian SOCS proteins have been well studied, little is known about the roles of SOCS in fish during viral infection. In this study, the molecular characteristics of SOCS9 from orange-spotted grouper (Epinephelus coioides, EcSOCS9) is investigated. The EcSOCS9 protein encoded 543 amino acids with typical SH2 (389-475aa) and SOCS_box (491-527aa), sharing high identities with reported fish SOCS9. EcSOCS9 was expressed in all detected tissues and highly expressed in kidney. After red-spotted grouper nervous necrosis virus (RGNNV) infection, the expression of EcSOCS9 was significantly induced in vitro. Furthermore, EcSOCS9 overexpression enhanced RGNNV replication, promoted virus-induced mitophagy that evidenced by the increased level of LC3-Ⅱ, BCL2, PGAM5 and decreased level of BNIP3 and FUNDC1. Besides, EcSOCS9 overexpression suppressed the expression levels of ATP6, CYB, ND4, ATP level and induced ROS level. The expression levels of interferon (IFN) related factors (IRF1, IRF3, IRF7, P53), inflammatory factors (IL1-β, IL8, TLR2, TNF-α) and IFN-3, ISRE, NF-κB, AP1 activities were also reduced by overexpressing EcSOCS9. These date suggests that EcSOCS9 impacts RGNNV infection through modulating mitophagy, regulating the expression levels of IFN- related and inflammatory factors, which will expand our understanding of fish immune responses during viral infection.

Di-(2-ethylhexyl) phthalate induces ferroptosis in prepubertal mouse testes via the lipid metabolism pathway

Di-(2-ethylhexyl) phthalate (DEHP), a widely used plasticizer, has been shown to cause reproductive toxicity, but the precise mechanism remains unclear. This study aimed to investigate the possible molecular mechanism of DEHP-induced testicular damage. In vivo study, we administered different doses of DEHP (0, 250, and 500 mg/kg/day) to male C57BL/6 mice from 22 and 35 days after birth. We found that DEHP exposure induced histopathological alterations in prepubertal testes, and testicular lipidomics indicated notable alterations in lipid metabolism and significant enrichment of ferroptosis. Further tests showed that ferrous iron (Fe2+ ) and malondialdehyde (MDA) levels significantly increased after DEHP exposure. Western blotting revealed that DEHP exposure reduced glutathione peroxidase 4 (GPX4) expression, and elevated acyl coenzyme A synthetase long-chain member 4 (ACSL4) and lysophosphatidylcholine acyltransferase 3 (LPCAT3) expression. The in vitro results were consistent with the in vivo results. When Leydig cells and Sertoli cells were treated with ferrostatin-1 and monoethylhexyl phthalate (MEHP), MEHP-induced increases in Fe2+ and MDA levels, accumulation of lipid reactive oxygen species, downregulation of GPX4, and upregulation of ACSL4 and LPCAT3 were reversed. Collectively, our findings suggested that aberrant lipid metabolism and ferroptosis may be involved in prepubertal DEHP exposure-induced testicular damage.

PPARβ/δ-ANGPTL4 axis mediates the promotion of mono-2-ethylhexyl phthalic acid on MYCN-amplified neuroblastoma development

Di-2-ethylhexyl phthalic acid (DEHP) is one of the most widely used plasticizers in the industry, which can improve the flexibility and durability of plastics. It is prone to migrate from various daily plastic products through wear and leaching into the surrounding environment and decompose into the more toxic metabolite mono-2-ethylhexyl phthalic acid (MEHP) after entering the human body. However, the impacts and mechanisms of MEHP on neuroblastoma are unclear. We exposed MYCN-amplified neuroblastoma SK-N-BE(2)C cells to an environmentally related concentration of MEHP and found that MEHP increased the proliferation and migration ability of tumor cells. The peroxisome proliferator-activated receptor (PPAR) β/δ pathway was identified as a pivotal signaling pathway in neuroblastoma, mediating the effects of MEHP through transcriptional sequencing analysis. Because MEHP can bind to the PPARβ/δ protein and initiate the expression of the downstream gene angiopoietin-like 4 (ANGPTL4), the PPARβ/δ-specific agonist GW501516 and antagonist GSK3787, the recombinant human ANGPTL4 protein, and the knockdown of gene expression confirmed the regulation of the PPARβ/δ-ANGPTL4 axis on the malignant phenotype of neuroblastoma. Based on the critical role of PPARβ/δ and ANGPTL4 in the metabolic process, a non-targeted metabolomics analysis revealed that MEHP altered multiple metabolic pathways, particularly lipid metabolites involving fatty acyls, glycerophospholipids, and sterol lipids, which may also be potential factors promoting tumor progression. We have demonstrated for the first time that MEHP can target binding to PPARβ/δ and affect the progression of neuroblastoma by activating the PPARβ/δ-ANGPTL4 axis. This mechanism confirms the health risks of plasticizers as tumor promoters and provides new data support for targeted prevention and treatment of neuroblastoma.

MXene-Enhanced Bi2S3/CdIn2S4 Heterojunction Photosensitive Gate for DEHP Detection in a Signal-On OPECT Aptamer Biosensor

Organic electrochemical transistors with signal amplification and good stability are expected to play a more important role in the detection of environmental pollutants. However, the bias voltage at the gate may have an effect on the activity of vulnerable biomolecules. In this work, a novel organic photoelectrochemical transistor (OPECT) aptamer biosensor was developed for di(2-ethylhexyl) phthalate (DEHP) detection by combining photoelectrochemical analysis with an organic electrochemical transistor, where MXene/Bi2S3/CdIn2S4 was employed as a photoactive material, target-dependent DNA hybridization chain reaction was used as a signal amplification unit, and Ru(NH3)63+ was selected as a signal enhancement molecule. The poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-based OPECT biosensor modulated by the MXene/Bi2S3/CdIn2S4 photosensitive material achieved a high current gain of nearly a thousand times at zero bias voltage. The developed signal-on OPECT sensing platform realized sensitive and specific detection of DEHP, with a detection range of 1-200 pM and a minimum detection limit of 0.24 pM under optimized experimental conditions, and its application to real water samples was also evaluated with satisfactory results. Hence, the construction of this OPECT biosensing platform not only provides a promising tool for the detection of DEHP but also reveals the great potential of the OPECT application for the detection of other environmental toxins.

ARTS is essential for di-2-ethylhexyl phthalate (DEHP)-induced apoptosis of mouse Leydig cells

As an extensively employed plasticizer in industrial applications, di-2-ethylhexyl phthalate (DEHP) can induce apoptosis of mouse Leydig cells, yet the precise mechanism remains elusive. In the current study, we identified that DEHP could specially induced apoptosis in the Leydig cells of the testis tissue, accompanied with the upregulation of apoptosis-related protein in the TGF-β signaling pathway (ARTS) in the cells. Overexpression of ARTS significantly induced apoptosis of TM3 cells, while knockdown of ARTS inhibited apoptosis. Furthermore, DEHP-induced apoptosis of TM3 cells could be alleviated by knockdown of ARTS, which indicated that ARTS was involved in DEHP-induced apoptosis of mouse Leydig cells. Bioinformation assay predicts that there are four potential p53-responsive elements (p53-REs) located at - 6060, - 5726, - 5631 and - 5554 before the transcription start site of ARTS gene, implying that gene transcription of ARTS could be regulated by p53. Interestingly, DEHP was shown to specifically upregulate the expression of p53 in the Leydig cells of the testis tissue and TM3 cells. Consistently, p53 was proved to bind to the RE4 site of the ARTS gene promoter and transcriptionally activated the promoter-driven expression of the luciferase reporter gene. Overexpression of p53 could induce apoptosis of TM3 cells; while knockdown of p53 could not only rescue DEHP-induced apoptosis of the cells, but also inhibit DEHP-caused upregulation of ARTS. Meanwhile, we showed that oxidative stress could induce apoptosis of TM3 cells, accompanied with the increased protein levels of p53 and ARTS; while inhibition of oxidative stress dramatically alleviated DEHP-induced apoptosis and the up-regulation of p53 and ARTS. Taken together, these results indicated that DEHP-induced oxidative stress activates the p53-ARTS cascade to promote apoptosis of mouse Leydig cells.

Post-Subfunctionalization Functions of HIF-1αA and HIF-1αB in Cyprinid Fish: Fine-Tuning Mitophagy and Apoptosis Regulation Under Hypoxic Stress

Hypoxia-inducible factor 1 (HIF-1) is a crucial transcriptional factor that can restore oxygen balance in the body by regulating multiple vital activities. Two HIF-1α copies were retained in cyprinid fish after experiencing a teleost-specific genome duplication. How the "divergent collaboration" of HIF-1αA and HIF-1αB proceeds in regulating mitophagy and apoptosis under hypoxic stress in cells of cyprinid fish remains unclear. In this study, zebrafish HIF-1αA/B expression plasmids were constructed and transfected into the epithelioma papulosum cyprini cells and were subjected to hypoxic stress. HIF-1αA induced apoptosis through promoting ROS generation and mitochondrial depolarization when cells were subjected to oxygen deficiency. Conversely, HIF-1αB was primarily responsible for mitophagy induction, prompting ATP production to mitigate apoptosis. HIF-1αA did not induce mitophagy in the mitochondria and lysosomes co-localization assay but it was involved in the regulation of different mitophagy pathways. Over-expression of HIF-1αA increased the expression of bnip3, fundc1, Beclin1, and foxo3, suggesting it has a dual role in mitochondrial autophagy and cell death. Each duplicated copy also experienced functional divergence and target shifting in the regulation of complexes in the mitochondrial electron transport chain (ETC). Our findings shed light on the post-subfunctionalization function of HIF-1αA and HIF-1αB in zebrafish to fine-tune regulation of mitophagy and apoptosis following hypoxia exposure.

Mitochondrial dysfunction and endoplasmic reticulum stress induced by activation of PPARα leaded testicular to apoptosis in SD rats explored to di-(2-ethylhexyl) phthalate (DEHP)

Di-2-ethylhexyl phthalate (DEHP), as a common endocrine disrupting chemicals, can induce toxicity to reproductive system. However, the mechanism remains to be explored. In our study, DEHP exposure induced testicular injury in rats. The high throughput transcriptional sequencing was performed to identify differentially expressed genes (DEGs) between the treatment and control groups. KEGG analysis revealed that DEGs were enriched in apoptosis, PPARα, and ER stress pathway. DEHP up-regulated the expression of PPARα, Bax, Bim, caspase-4. GRP78, PERK, p-PERK, eIF2α, p-eIF2α, ATF4 and CHOP. This view has also been confirmed in TM3 and TM4 cells. In vitro, after pre-treatment with GW6471 (an inhibitor of PPARα) or GSK (an inhibitor of PERK), the apoptosis was inhibited and mitochondrial dysfunction was improved. Moreover, the improvement of mitochondrial dysfunction decreased the expression of PERK pathway by using SS-31(a protective agent for mitochondrial function). Interestingly, ER stress promoted the accumulation of ROS by ERO1L (the downstream of CHOP during ER stress), and the ROS further aggravated the ER stress, thus forming a feedback loop during the apoptosis. In this process, a vicious cycle consisting of PERK, eIF2α, ATF4, CHOP, ERO1L, ROS was involved. Taken together, our results suggested that mitochondrial dysfunction and ER stress-ROS feedback loop caused by PPARα activation played a crucial role in DEHP-induced apoptosis. This work provides insight into the mechanism of DEHP-induced reproductive toxicity.

Exploring the relationship between urinary phthalate metabolites and Crohn's disease via oxidative stress, and the potential moderating role of gut microbiota: A conditional mediation model

OBJECTIVE

Interactions between phthalic acid esters (PAEs) exposure and Crohn's disease (CD) were unknown. This study aims to examine the association between exposure to PAEs and CD activity and to explore the roles of oxidative stress and microbiota.

METHODS

A cross-sectional study with 127 CD patients was conducted. The disease activity was evaluated based on symptoms (Harvey-Bradshaw index, HBI), endoscopy findings (Simple Endoscopic Score for CD, SES-CD), and computed tomography enterography (CTE-scores). Ten urinary PAEs metabolites (mPAEs), two urinary oxidative stress biomarkers, including 8-hydroxydeoxyguanosine (8-OHdG) and 8-iso-prostaglandin-F2α (8-iso-PGF2α), as well as 16S rRNA sequencing of stool samples were determined. Multiple linear regression models and Hayes's PROCESS macro for SPSS were used to evaluate the interplays between urinary PAEs metabolites, CD activities, oxidative stress, and microbiota diversity.

RESULTS

There were positive associations between most mPAEs and HBI. Oxidative stress mediated 20.69-89.29% of the indirect associations between low molecular weight (LMW) mPAEs and HBI, while the majority of the high molecular weight (HMW) mPAEs were directly associated with HBI. In addition, microbiota diversity moderated the indirect associations of LMW mPAEs on HBI.

CONCLUSIONS

PAEs exposure was related to CD activity, and the association could be mediated by oxidative stress and reversed or alleviated by rich gut microbiota.

Alpha-lipoic Acid Protects Against Chronic Alcohol Consumption-induced Cardiac Damage by the Aldehyde Dehydrogenase 2-associated PINK/Parkin Pathway

ABSTRACT

Chronic alcohol intake contributes to high mortality rates due to ethanol-induced cardiac hypertrophy and contractile dysfunction, which are accompanied by increased oxidative stress and disrupted mitophagy. Alpha-lipoic acid (α-LA), a well-known antioxidant, has been shown to protect against cardiac hypertrophy and inflammation. However, little is known about its role and mechanism in the treatment of alcoholic cardiomyopathy. Here, we evaluated the role of α-LA in alcohol-induced cardiac damage by feeding mice a 4.8% (v/v) alcohol diet with or without α-LA for 6 w. Our results suggested that chronic alcohol consumption increased mortality, blood alcohol concentrations, and serum aldehyde levels, but a-LA attenuated the elevations in mortality and aldehydes. Chronic alcohol intake also induced cardiac dysfunction, including enlarged left ventricles, reduced left ventricular ejection fraction, enhanced cardiomyocyte size, and increased serum levels of brain natriuretic peptide, lactate dehydrogenase, and creatine kinase myocardial isoenzyme. Moreover, alcohol intake led to the accumulation of collagen fiber and mitochondrial dysfunction, the effects of which were alleviated by α-LA. In addition, α-LA intake also prevented the increase in reactive oxygen species production and the decrease in mitochondrial number that were observed after alcohol consumption. Chronic alcohol exposure activated PINK1/Parkin-mediated mitophagy. These effects were diminished by α-LA intake by the activation of aldehyde dehydrogenase 2. Our data indicated that α-LA helps protect cardiac cells against the effects of chronic alcohol intake, likely by inhibiting PINK1/Parkin-related mitophagy through the activation of aldehyde dehydrogenase 2.

Activation of the p62-Keap1-Nrf2 pathway protects against oxidative stress and excessive autophagy in ovarian granulosa cells to attenuate DEHP-induced ovarian impairment in mice

Di-(2-ethylhexyl) phthalate (DEHP) is widely used in various plastics but has been demonstrated to cause female reproductive toxicity. However, the exact mechanism underlying the ovarian damage induced by DEHP remains unclear. In this study, DEHP was administered orally to 5-week-old female mice for 30 days at doses of 0, 250, 500, and 1000 mg/kg/day. The findings demonstrated that DEHP exposure disrupted ovarian function and follicular development as well as induced oxidative stress and autophagy in ovarian granulosa cells (GCs). Further, 200 µM mono-(2-ethylhexyl) phthalate (MEHP), the primary metabolite of DEHP in vivo, induced autophagy in both human ovarian granulosa cells line (KGN) and mouse primary GCs within 24 h in vitro. However, it did not affect the p62-dependent autophagy flux. Furthermore, MEHP-induced autophagy was inhibited by the autophagy inhibitor 3-MA and exacerbated by the autophagy activator rapamycin, indicating that MEHP induces excessive autophagy in GCs. Subsequently, we found that MEHP-induced autophagic cell death was primarily attributed to oxidative damage from elevated intracellular ROS levels. Meanwhile, MEHP exposure induced nuclear translocation of erythroid-derived factor 2-related factor (Nrf2), a key regulator of antioxidant activity resulting in activating antioxidant effects. Interestingly, we also found that MEHP-induced increase in p62 competitively binds Keap1, thereby facilitating nuclear translocation of Nrf2 and establishing a positive feedback loop in antioxidant regulation. Therefore, this study demonstrated that inhibition of Nrf2 could aggravate oxidative damage and enhance excessive autophagy caused by MEHP, while activation of Nrf2 could reverse the trend. These findings have also been reinforced in studies of cultured ovaries in vitro. Our study suggests that the p62-Keap1-Nrf2 pathway may serve as a potential protective mechanism against DEHP-induced oxidative stress and excessive autophagy in mouse GCs.

Neurotoxicity and the potential molecular mechanisms of mono-2-ethylhexyl phthalic acid (MEHP) in zebrafish

Mono-2-ethylhexyl phthalic acid (MEHP) is the most toxic metabolite of plasticizer di-2-ethylhexyl phthalic acid (DEHP), and there is limited information available on the effects of MEHP on neurotoxicity. This study aims to examine the neurotoxicity of MEHP and preliminarily explore its potential molecular mechanisms. We found that MEHP impeded the growth of zebrafish embryos and the neurodevelopmental-related gene expression at environmentally relevant concentrations. MEHP exposure also induces oxidative stress response and brain cell apoptosis accompanied by a decrease in acetylcholinesterase (AChE) activity in zebrafish larvae. RNA-Seq and bioinformatics analysis showed that MEHP treatment altered the nervous system, neurogenic diseases, and visual perception pathways. The locomotor activity in dark-to-light cycles and phototaxis test confirmed the abnormal neural behavior of zebrafish larvae. Besides, the immune system has produced a large number of differentially expressed genes related to neural regulation. Inflammatory factor IL1β and IL-17 signaling pathways highly respond to MEHP, indicating that inflammation caused by immune system imbalance is a potential mechanism of MEHP-induced neurotoxicity. This study expands the understanding of the toxicity and molecular mechanisms of MEHP, providing a new perspective for in-depth neurotoxicity exploration of similar compounds.

Phthalate acid esters contribute to the cytotoxicity of mask leachate: Cell-based assay for toxicity assessment

After the COVID-19 outbreak, masks have become an essential part of people lives. Although several studies have been conducted to determine the release of hazardous substances from masks, how their co-presence poses a potential exposure risk to human health remains unexplored. In this study, we quantitatively compared the leaching of substances from six different common types of masks, including phthalate acid esters (PAEs), metals, and microplastics (MPs), and comprehensively evaluated the potential cytotoxicity of different leachates. MPs smaller than 3 µm were quantified by Py-GC-MS, and reusable masks showed greater releasing potentials up to 1504 µg/g. We also detected the prevalence of PAEs in masks, with the highest release reaching 42 μg/g, with dibutyl phthalate (DBP), diisobutyl phthalate (DiBP) and bis (2-ethylhexyl) phthalate (DEHP) being the predominant types. Moreover, the antimicrobial cloth masks released 173.0 µg of Cu or 4.5 µg of Ag, representing 2.7% and 0.04% of the original masks, respectively. Our cell-based assay results demonstrated for the first time that mask leachate induced nuclear condensation with DNA damage, and simultaneously triggered high levels of glutathione and reactive oxidative stress production, which exacerbated mitochondrial fragmentation, eventually leading to cell death. Combined with substance identification and correlation analysis, PAEs were found to be the contributors to cytotoxicity. Masks containing Cu or Ag led to acidification of lysosomes and alkalinization of cells. These results strongly suggested that the levels of PAEs in the production of regulatory masks should be strictly controlled.

NEDD4 activates mitophagy by interacting with LC3 to restrain reactive oxygen species and apoptosis in Apostichopus japonicus challenged with Vibrio splendidus

Mitophagy, the selective degradation of damaged mitochondria by autophagy, plays a crucial role in the survival of coelomocytes in Apostichopus japonicus following Vibrio splendidus infection by suppressing the generation of reactive oxygen species (ROS) and attenuating cell apoptosis. A recent study revealed that reducing the expression of the neural precursor cell-expressed developmentally downregulated gene 4 (NEDD4), an enzyme 3 (E3) ubiquitin ligase, significantly affects mitochondrial degradation. Prior to the present study, the functional role of NEDD4 in marine invertebrates was largely unexplored. Therefore, we investigated the role of NEDD4 in the activation of mitophagy, modulation of ROS levels, and induction of apoptosis in A. japonicus infected with V. splendidus. The results demonstrated that V. splendidus infection and lipopolysaccharide (LPS) challenge significantly increased the mRNA levels of NEDD4 in A. japonicus coelomocytes, which was consistent with changes in mitophagy under the same conditions. Knockdown of AjNEDD4 using specific small interfering RNAs (siRNAs) impaired mitophagy and caused accumulation of damaged mitochondria, as observed using transmission electron microscopy (TEM) and confocal microscopy. Furthermore, AjNEDD4 was localized to the mitochondria in both coelomocytes and HEK293T cells. Simultaneously, coelomocytes were treated with the inhibitor indole-3-carbinol (I3C) to confirm the regulatory role of AjNEDD4 in mitophagy. The accumulation of AjNEDD4 in the mitochondria and the level of mitophagy decreased. Subsequent investigations demonstrated that AjNEDD4 interacts directly with the microtubule-associated protein light chain 3 (LC3), a key regulator of autophagy and mitophagy, indicating its involvement in the mitophagy pathway. Moreover, AjNEDD4 interference hindered the interaction between AjNEDD4 and LC3, thereby impairing the engulfment and subsequent clearance of damaged mitochondria. Finally, AjNEDD4 interference led to a significant increase in intracellular ROS levels, followed by increased apoptosis. Collectively, these findings suggest that NEDD4 acts as a crucial regulator of mitophagy in A. japonicus and plays a vital role in maintaining cellular homeostasis following V. splendidus infection. NEDD4 suppresses ROS production and subsequent apoptosis by promoting mitophagy, thereby safeguarding the survival of A. japonicus under pathogenic conditions. Further investigation of the mechanisms underlying NEDD4-mediated mitophagy may provide valuable insights into the development of novel strategies for disease control in aquaculture farms.

Mono-(2-ethylhexyl)-phthalate potentiates methylglyoxal-induced blood-brain barrier damage via mitochondria-derived oxidative stress and bioenergetic perturbation

Phthalates in contaminated foods and personal care products are one of the most frequently exposed chemicals with a public health concern. Phthalate exposure is related to cardiovascular diseases, including diabetic vascular complications and cerebrovascular diseases, yet the mechanism is still unclear. The blood-brain barrier (BBB) integrity disruption is strongly associated with cardiovascular and neurological disease exacerbation. We investigated BBB damage by di-(2-ethylhexyl) phthalate (DEHP) or its metabolite mono-(2-ethylhexyl) phthalate (MEHP) using brain endothelial cells and rat models. BBB damage by the subthreshold level of MEHP, but not a DEHP, significantly increased by the presence of methylglyoxal (MG), a reactive dicarbonyl compound whose levels increase in the blood in hyperglycemic conditions in diabetic patients. Significant potentiation in apoptosis and autophagy activation, mitochondria-derived reactive oxygen species (ROS) production, and mitochondrial metabolic disturbance were observed in brain ECs by co-exposure to MG and MEHP. N-acetyl cysteine (NAC) restored autophagy activation as well as tight junction protein impairment induced by co-exposure to MG and MEHP. Intraperitoneal administration of MG and MEHP significantly altered mitochondrial membrane potential and tight junction integrity in rat brain endothelium. This study may provide novel insights into enhancing phthalate toxicity in susceptible populations, such as diabetic patients.

The mediating role of telomere length in multi-pollutant exposure associated with metabolic syndrome in adults

Metabolic syndrome is a chronic and complex disease characterized by environmental and genetic factors. However, the underlying mechanisms remain unclear. This study assessed the relationship between exposure to a mixture of environmental chemicals and metabolic syndrome (MetS) and further examined whether telomere length (TL) moderated these relationships. A total of 1265 adults aged > 20 years participated in the study. Data on multiple pollutants (polycyclic aromatic hydrocarbons, phthalates, and metals), MetS, leukocyte telomere length (LTL), and confounders were provided in the 2001-2002 National Health and Nutrition Examination Survey. The correlations between multi-pollutant exposure, TL, and MetS in the males and females were separately assessed using principal component analysis (PCA), logistic and extended linear regression models, Bayesian kernel machine regression (BKMR), and mediation analysis. Four factors were generated in PCA that accounted for 76.2% and 77.5% of the total environmental pollutants in males and females, respectively. The highest quantiles of PC2 and PC4 were associated with the risk of TL shortening (P < 0.05). We observed that the relationship between PC2, PC4, and MetS risk was significant in the participants with median TL levels (P for trend = 0.04 for PC2, and P for trend = 0.01 for PC4). Furthermore, mediation analysis revealed that TL could explain 26.1% and 17.1% of the effects of PC2 and PC4 associated with MetS in males, respectively. The results of BKMR model revealed that these associations were mainly driven by 1-PYE (cPIP = 0.65) and Cd (cPIP = 0.29) in PC2. Meanwhile, TL could explain 17.7% of the mediation effects of PC2 associated with MetS in the females. However, the relationships between pollutants and MetS were sparse and inconsistent in the females. Our findings suggest that the effects of the risk of MetS associated with mixed exposure to multiple pollutants are mediated by TL, and this mediating effect in the males is more pronounced than that in the females.

Epigallocatechin gallate alleviates mono-2-ethylhexyl phthalate-induced male germ cell pyroptosis by inhibiting the ROS/mTOR/NLRP3 pathway

Mono-2-ethylhexyl phthalate (MEHP) exposure is known to induce severe testicular injury via reactive oxygen species (ROS). However, few effective treatments are available for the precise treatment of MEHP-induced germ cell damage. Epigallocatechin gallate (EGCG), one of the major polyphenols in green tea, has potential antioxidant activity and can alleviate many diseases induced by oxidative stress. This study explored whether EGCG protects germ cells from MEHP-induced oxidative stress damage. Cells were treated with 400 μM MEHP and 60 μM EGCG for 24 h. EGCG reduced MEHP-induced ROS overgeneration in the spermatogonial cell line GC-1 and spermatocyte cell line GC-2. Western blotting and immunofluorescence showed that the MEHP+EGCG group exhibited lower nuclear factor (erythroid-derived 2)-like 2 (NRF2), heme oxygenase (decycling) 1 (HO-1), and superoxide dismutase (SOD) expression than the MEHP group. Moreover, activation of the mammalian target of rapamycin (mTOR) pathway was decreased. The expression of key factors of pyroptosis was downregulated, and interleukin-10 (IL-10) expression was reduced. Additionally, apoptosis was inhibited by EGCG. The findings indicate that EGCG protects against MEHP-induced germ cell pyroptosis by scavenging ROS, suppressing the mTOR pathway, and inhibiting pyroptosis. EGCG may thus be a potential treatment for MEHP-related spermatogenic dysfunction.

Assessment of lipid metabolism-disrupting effects of non-phthalate plasticizer diisobutyl adipate through in silico and in vitro approaches

Diisobutyl adipate (DIBA), as a novel non-phthalate plasticizer, is widely used in various products. However, little effort has been made to investigate whether DIBA might have adverse effects on human health. In this study, we integrated an in silico and in vitro strategy to assess the impact of DIBA on cellular homeostasis. Since numerous plasticizers could activate peroxisome proliferator-activated receptor γ (PPARγ) pathway to interrupt metabolism systems, we first utilized molecular docking to analyze interaction between DIBA and PPARγ. Results indicated that DIBA had strong affinity with the ligand-binding domain of PPARγ (PPARγ-LBD) at Histidine 499. Afterwards, we used cellular models to investigate in vitro effects of DIBA. Results demonstrated that DIBA exposure increased intracellular lipid content in murine and human hepatocytes, and altered transcriptional expression of genes related to PPARγ signaling and lipid metabolism pathways. At last, target genes regulated by DIBA were predicted and enriched for Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Protein-protein interaction (PPI) network and transcriptional factors (TFs)-genes network were established accordingly. Target genes were enriched in Phospholipase D signaling pathway, phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) and Epidermal growth factor receptor (EGFR) signaling pathway which were related to lipid metabolism. These findings suggested that DIBA exposure might disturb intracellular lipid metabolism homeostasis via targeting PPARγ. This study also demonstrated that this integrated in silico and in vitro methodology could be utilized as a high throughput, cost-saving and effective tool to assess the potential risk of various environmental chemicals on human health.

Insight into the health risk implicated in mitochondrial toxicity of dibutyl phthalate exposure on zebrafish (Danio rerio) cells

Dibutyl phthalate (DBP) is commonly applied plasticizer in plastic products such as face masks, easily leaches or migrates into environment and its widespread contamination posed profound health risks. Further concerns rise regarding to the toxicity of DBP at subcellular level, while little is known about the ranging effects on mitochondrial susceptibility. Present study investigated the mitochondrial impairments with implicated cell death upon DBP exposure on zebrafish cells. Elevated mitochondrial oxidative stress reduced its membrane potential and count, enhanced fragmentation, and impaired ultrastructure that showed smaller size and cristae rupture. Afterwards, the critical function of ATP synthesis was damaged and the stabilized binding capacity between DBP with mitochondrial respiratory complexes was simulated by the molecular docking. And the top pathways enrichment of mitochondrion and metabolism by transcriptome analyses verified the mitochondrial dysfunction that indicated the human diseases risks. The mitochondrial DNA (mtDNA) replication and transcription with DNA methylation modifications were also disrupted, reflecting the genotoxicity on mtDNA. Moreover, the activated autophagy and apoptosis underlying mitochondrial susceptibility integrated into cellular homeostasis changes. These findings provide the first systemic evidence broadening and illustrating the mitochondrial toxicity of DBP exposure on zebrafish model that raise concern on phthalates contamination and ecotoxicological evaluation.

Di(2-ethylhexyl) phthalate and microplastics cause necroptosis and apoptosis in hepatocytes of mice by inducing oxidative stress

Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer and an endocrine disruptor. Microplastics (MPs) are pathogenic small plastic particles and abundant in the aqueous environment. The problem of residual hazards of plastic products is worthy of study, especially the joint exposure of a variety of plastic-related products to the toxic effect. We used 200 mg/kg DEHP and 10 mg/L MPs to establish exposure model in vivo and 2 mM DEHP and 200 μg/L MPs to establish AML12 cell exposure model in vitro. In vivo study results showed that compared with the control group (NC) group, DEHP and MPs significantly increased the contents of malondialdehyde and hydrogen peroxide, and significantly decreased the contents of glutathione and the activity of superoxide dismutase, total antioxidant capacity, catalase and glutathione peroxidase. The level of oxidative stress was further aggravated after combined exposure. The reactive oxygen species level of AML12 exposed to DEHP and MPs in vitro was significantly higher than NC group, and the combined exposure was significantly higher than the single exposure. The in vivo and in vitro also confirmed that DEHP and MPs could significantly increase the mRNA and protein levels of apoptosis markers and necroptosis markers and there was an additive effect. After N-acetylcysteine treatment in vitro, the above-mentioned oxidative stress level and cell damage decreased significantly. This study provided a reference for advocating the reduction of the mixed use of plastic products, and provided a basis for preventing the harm of plastic products residues.

Distribution of Micro-Nano PS, DEHP, and/or MEHP in Mice and Nerve Cell Models In Vitro after Exposure to Micro-Nano PS and DEHP

Polystyrene (PS) and di-(2-ethylhexyl) phthalate (DEHP) exist widely in the environment. However, their distribution in organisms remains unclear. We used three sizes (50 nm, 500 nm, and 5 μm) of PS and DEHP to study the distribution and accumulation of PS, DEHP, and mono(2-ethylhexyl) phthalate (MEHP) in mice and nerve cell models (HT22 and BV2 cells) and their potential toxicity. Results showed that PS entered the blood of mice, and the distribution of different particle sizes in different tissues was different. After the combined exposure to PS and DEHP, PS carried DEHP, which significantly increased the DEHP content and MEHP content and the highest content of MEHP was in the brain. With the decrease in PS particle size, the contents of PS, DEHP, and MEHP in the body increased. The levels of inflammatory factors were increased in the serum of the PS or/and DEHP group. In addition, 50 nm polystyrene can carry MEHP into nerve cells. These results suggest for the first time that PS and DEHP combined exposure can induce systemic inflammation, and the brain is an important target organ of PS and DEHP combined exposure. This study may serve as a reference for further evaluation of the neurotoxicity induced by combined exposure to PS and DEHP.

Mitocytosis Is Critical for Phthalate-Induced Injury to the Ovarian Granulosa Cell Layer in Quail (Coturnix japonica)

Phthalates are widely used synthetic chemicals that determine endocrine disruption effects on female reproductivity and oviposition. Our study demonstrated that the mitochondrial quality in ovarian granulosa cells (GCs) is associated with a poor prognosis in female reproduction. However, the molecular mechanism of di-(2-ethylhexyl) phthalate (DEHP) exposure on the quail ovarian GC layer is still unknown. To validate the effects of DEHP on the GC layer, 8 days' old 150 female Japanese quail were treated orally with DEHP (250, 500, and 750 mg/kg BW/day) for 45 days to explore the toxic effects of DEHP on the ovarian GC layer. Histopathological assessment and ultrastructure observation found that DEHP decreased the thickness of the GC layer, resulted in mitochondrial damage, and activated mitocytosis. Additionally, the results further suggested that DEHP impacted the secretion of steroid hormones (reduced FSH, E2, and T levels and boosted Prog, PRL, and LH levels) by triggering mitocytosis (enhanced transcription of MYO19 and protein of KIF5B levels), mitochondrial dynamics (increasing mRNA and protein levels of OPA1, DRP1, MFN1, and MFN2), mitophagy (increasing mRNA and protein levels of Parkin, LC3B, and P62), and inducing GC function disorder. In conclusion, our research provided a new idea to explain the mechanism of DEHP toxicity of the ovarian GC layer in quail and presented insights into the role of mitocytosis in DEHP-induced ovarian GC layer injury.

FAM72A promotes glioma progression by regulating mitophagy through the Pink1/Parkin signaling pathway

Background: There is growing evidence that aberrant expression of FAM72A contributes to biological dysfunction, especially mitochondrial dysfunction. However, its role in most tumors remains unclear, especially in glioma. Methods: Herein, a high-throughput sequencing approach was used here to identify FAM72A as the target molecule. Next, we detected the protein and mRNA expression levels of FAM72A in normal brain tissue (NBT) as well as different grades of glioma tissue. CCK-8, colony formation, Transwell assays, and Western blotting, were all used to determine the molecular effects of FAM72A on glioma cells. Results: FAM72A was significantly upregulated in glioma, was significantly correlated with WHO grade and was associated with poor clinical outcomes. In functional assays, FAM72A was shown to promote glioma cell growth. Subsequent mechanistic studies indicated that FAM72A promoted glioma progression by regulating mitophagy through the Pink1/Parkin signaling pathway. In addition, FAM72A promoted mitophagy and maintained Pink1 stability through the Pink1/Parkin signaling pathway. Finally, FAM72A promoted tumor immune escape by upregulating PD-L1 expression. Conclusion: All of these data indicate that FAM72A confers an aggressive phenotype and poor prognosis on gliomas. Targeting FAM72A might represent a new therapeutic strategy for glioma.

Manganese-induced PINK1 S-nitrosylation exacerbates nerve cell damage by promoting ZNF746 repression of mitochondrial biogenesis

Occupational exposure and non-occupational exposure to excessive levels of manganese (Mn) result in neuronal cell damage through mitochondrial dysfunction. The functional integrity of mitochondria is maintained by mitophagy and mitochondrial biogenesis. Although Mn-induced S-nitrosylation of PTEN-induced putative kinase 1 (PINK1) can interfere with mitophagy, its effect on mitochondrial biogenesis remains unclear. In this study, we established a rat model of Mn poisoning or "manganism" to examine the relationship between PINK1 S-nitrosylation and impairment of mitochondrial biogenesis, and found that treatment with 60 mg/kg Mn induced marked neurobehavioral abnormalities in rats and significantly increased the S-nitrosylation level of PINK1. We also found that the nuclear-encoded peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PPARGC1A)-mediated mitochondrial biogenesis was significantly upregulated in rats treated with 15 and 30 mg/kg Mn, and downregulated in rats treated with 60 mg/kg Mn. We further investigated the role of S-nitrosylated PINK1 and its molecular mechanism in the high-dose Mn-mediated impairment of mitochondrial biogenesis in primary cultured neurons treated with the nitric oxide synthase 2 (NOS2) inhibitor 1400 W. Our results revealed that the PPARGC1A-mediated mitochondrial biogenesis was upregulated in neurons treated with 100 μM, but downregulated in neurons treated with 200 μM Mn, which was similar to the in vivo results. However, treatment with 1400W could effectively prevent the 200 μM Mn-mediated impairment of mitochondrial biogenesis by suppressing nitric oxide (NO)-mediated PINK1 S-nitrosylation and rescuing Parkin-interacting substrate (PARIS, ZNF746) degradation, thereby upregulating mitochondrial biogenesis via PPARGC1A. These findings demonstrated that S-nitrosylation of PINK1 and subsequent prevention of ZNF746 degradation were crucial signaling processes involved in the Mn-mediated impairment of mitochondrial biogenesis, which might serve as an underlying mechanism of Mn-induced neurotoxicity. Furthermore, this study provided a reliable target for the prevention and treatment of manganism.

Effects of phthalates on human chorionic trophoblast cells and mouse embryonic development

Phthalate exposure is associated with reproductive health, but the mechanism is unclear. This study used human chorionic trophoblast epithelial cells (HTR8/Svneo cells) and mouse embryos as objects aims to explore the effects of phthalate plasticizers on germ cells and fertility and the possible signalling pathways. In the present study, high concentrations of MEHP for 24 h significantly inhibited the proliferation and viability of HTR8/SVneo cells. Compared with the negative control (NC) group, the MEHP medium and high concentration groups promoted the apoptosis of HTR8/SVneo cells and inhibited the cell cycle, HTR8/SVneo cells were blocked in G1/G0 phase and could not enter S phase, and cell meiosis was inhibited. Western blot experiments showed that there was no difference in the protein expression of wnt inhibitory factor 1 (WIF1) and β-catenin in HTR8/SVneo cells between the MEHP exposure groups and the NC groups. In vitro embryo culture experiments found that there was no difference in blastocyst formation rate among groups after exposure to DEHP for 2 h. Immunofluorescence showed that the expression of WIF1 decreased in the low concentration group, and there was no difference in the medium and high concentration groups, while the expression of β-catenin was increased in both the low concentration group and the high concentration group. Our data suggest that exposure to phthalate plasticizers can affect the viability, cell cycle and apoptosis of trophoblast cells, resulting in abnormal expression of the embryonic WIF1/β-catenin signalling pathway and impaired fertility.

Phthalate induces mitochondrial injury in cerebellum through Sirt1-PGC-1α and PINK1/Parkin-mediated signal pathways

Di-(2-ethylhexyl) phthalate (DEHP) is an environmental toxicant that is widely used in the whole world as a plasticizer that can enhance plastic properties. A number of reserarches have demonstrated that DEHP could cause varying degrees of damage to the normal function of nerve. The research aimed to investigate the mechanism of DEHP-induced cerebellar toxicity. In present study, we set DEHP-caused cerebellar injury models of quail and implied that DEHP induced cerebellar dysplasia by abnormity of Purkinje cell and reduction of cerebellar granule cell. Furthermore, the mitochondrial damage was confirmed by the swelling, cristae reduction, membrane rupture of mitochondria or even the occurrence of autophagic vacuole. To clarified DEHP-induced mitochondrial damage in cerebellum, we examined the relevant genes of mitochondrial biogenesis, mitochondrial dynamics, oxidative damage, the pathways related to Nrf2 and PINK1/Parkin in cerebellum. Based on data, it appeared that DEHP treatment had a damaging effect on the cerebellum and led to mitophagy as well as oxidative stress. In conclusion, the research indicated that DEHP-actuated mitochondrial injury has a directly relationship with mitophagy. DEHP-actuated reduced mitochondrial biogenesis and dysregulation of mitochondrial dynamics. The increase of oxidative stress damaged mitochondria, and the redundant ROS in damaged mitochondria that gave rise to cerebellar harm.

PM2.5 increases susceptibility to acute exacerbation of COPD via NOX4/Nrf2 redox imbalance-mediated mitophagy

The increasing abundance of fine particulate matter (PM2.5) in the environment has increased susceptibility to acute exacerbation of COPD (AECOPD). During PM2.5 exposure, excessive reactive oxygen species (ROS) production triggers a redox imbalance, which contributes to damage to organelles and disruption of homeostasis. At present, there are limited data on whether NOX4/Nrf2 redox imbalance increases susceptibility to acute exacerbation of COPD (AECOPD), and the underlying mechanism is unclear. Therefore, the current study was aimed to evaluate the role of NOX4/Nrf2 redox balance on AECOPD induced by PM2.5-CS-exposure. Here, we report that PM2.5 exacerbates cytotoxicity by enhancing NOX4/Nrf2 redox imbalance-mediated mitophagy. First, exposure to a low-dose of PM2.5 (200 μg/ml) significantly exacerbated oxidative stress and mitochondrial damage by increasing the ROS overproduction, enhancing the excessive NOX4/Nrf2 redox imbalance, decreasing the mitochondrial membrane potential (MMP), and enhancing the mitochondrial fragmentation that were caused by a low-dose of CSE (2.5%). Second, coexposure to PM2.5 and CSE (PM2.5-CSE) induced excessive mitophagy. Third, PM2.5 exacerbated CS-induced COPD, as shown by excessive inflammatory cell infiltration, inflammatory cytokine production and mucus hypersecretion, goblet cell hyperplasia, NOX4/Nrf2 redox imbalance, and mitophagy, these effects triggered excessive ROS production and mitochondrial damage in mice. Mechanistically, PM2.5-CS-induced excessive levels of mitophagy by triggering redox imbalance, leading to greater cytotoxicity and AECOPD; however, reestablishing the NOX4/Nrf2 redox balance via NOX4 blockade or mitochondria-specific ROS inhibitor treatment alleviated this cytotoxicity and ameliorated AECOPD. PM2.5 may exacerbate NOX4/Nrf2 redox imbalance and subsequently enhance mitophagy by increasing the ROS and mito-ROS levels, thereby increasing susceptibility to AECOPD.

Combined exposure to di(2-ethylhexyl) phthalate and polystyrene microplastics induced renal autophagy through the ROS/AMPK/ULK1 pathway

Di(2-ethylhexyl) phthalate (DEHP) and polystyrene microplastics (PS-MPs) are new environmental pollutants that attracted increased attention. At present, the effects and underlying mechanisms of action of combined exposure of DEHP and PS-MPs on the kidney have not been elucidated. To investigate the renal toxicity of DEHP and PS-MPs exposure, we established single and combined DEHP and PS-MPs exposure models in mice and HEK293 cells, respectively. Hematoxylin and eosin staining, transmission electron microscopy, monodansylcadaverine staining, immunofluorescence, real-time quantitative PCR, Western blot analysis and other methods were used to detect relevant indicators. The results showed that the expression levels of ROS/AMPK/ULK1 and Ppargc1α/Mfn2 signaling pathway-related genes were significantly increased in the DEHP and PS-MPs exposure models. The mRNA and protein expression levels of autophagy markers were also upregulated. In addition, we found that the expression levels of mRNAs and proteins in the combined exposure group were more significantly increased than those in the single exposure group. In conclusion, combined exposure to DEHP and PS-MPs caused oxidative stress and activated the AMPK/ULK1 pathway, thereby inducing renal autophagy. Our results enhance the field of nephrotoxicity studies of plasticizers and microplastics and provide new light on combined toxicity studies of DEHP and PS-MPs.

Thiostrepton confers protection against reactive oxygen species-related apoptosis by restraining FOXM1-triggerred development of gastric cancer

Gastric cancer is a leading cause of tumor-associated death worldwide. Metastasis and chemoresistance are crucial barriers for gastric cancer treatment. The Forkhead Box M1 (FOXM1) transcription factor has been reported as a promising treatment target for various types of tumors, but its effects on gastric cancer progression are not fully understood. In the present study, we found that FOXM1 expression levels were significantly up-regulated in human gastric cancer cell lines and tissues, and its expression was much higher in patients with metastasis. We then found that suppressing FOXM1 with its inhibitor thiostrepton (THIO) significantly reduced the proliferation of gastric cancer cells, while induced G0/G1 and apoptosis. Moreover, reactive oxygen species (ROS) production, mitochondrial impair and autophagy were remarkably provoked in gastric cancer cells treated with THIO, which were required for the regulation of apoptotic cell death. Furthermore, THIO exposure considerably suppressed the migration, invasion and angiogenesis in gastric cancer cells. The inhibitory effects of THIO on tumor growth and metastasis were confirmed in an established gastric cancer xenograft mouse model without detectable toxicity. Intriguingly, our in vitro studies showed that the anti-cancer effects of THIO on gastric cancer were almost abolished upon FOXM1 over-expression, indicating the necessity of FOXM1 suppression in THIO-inhibited tumor growth. In addition, higher FOXM1 expression was detected in gastric cancer cells with chemoresistance. Both in vitro and in vivo studies illustrated that THIO strongly promoted the drug-resistant gastric cancer cells to chemotherapies, proved by the considerably decreased cell proliferation and epithelial-mesenchymal transition (EMT) process. Together, these findings revealed that FOXM1 was a promising therapeutic target for gastric cancer treatment, and THIO exerted potential as an therapeutic agent for the disease.

Adverse cardiovascular effects and potential molecular mechanisms of DEHP and its metabolites-A review

Currently, cardiovascular disease (CVD) is a health hazard that is associated with progressive deterioration upon exposure to environmental pollutants. Di(2-ethylhexyl) phthalate (DEHP) has been one of the focuses of emerging concern due to its ubiquitous nature and its toxicity to the cardiovascular (CV) system. DEHP has been noted as a causative risk factor or a risk indicator for the initiation and augment of CVDs. DEHP represents a precursor that contributes to the pathogenesis of CVDs through its active metabolites, which mainly include mono (2-ethylhexyl) phthalate (MEHP). Herein, we systematically presented the association between DEHP and its metabolites and adverse CV outcomes and discussed the corresponding effects, underlying mechanisms and possibly interventions. Epidemiological and experimental evidence has suggested that DEHP and its metabolites have significant impacts on processes and factors involved in CVD, such as cardiac developmental toxicity, cardiac injury and apoptosis, cardiac arrhythmogenesis, cardiac metabolic disorders, vascular structural damage, atherogenesis, coronary heart disease and hypertension. DNA methylation, PPAR-related pathways, oxidative stress and inflammation, Ca²⁺ homeostasis disturbance may pinpoint the relevant mechanisms. The preventive and therapeutic measures are potentially related with P-glycoprotein, heat-shock proteins, some antioxidants, curcumin, apigenin, β-thujaplicin, glucagon-like peptide-1 receptor agonists and Ang-converting enzyme inhibitors and so on. Promisingly, future investigations should aid in thoroughly assessing the causal relationship and molecular interactions between CVD and DEHP and its metabolites and explore feasible prevention and treatment measures accordingly.

The critical role of the endolysosomal system in cerebral ischemia

Cerebral ischemia is a serious disease that triggers sequential pathological mechanisms, leading to significant morbidity and mortality. Although most studies to date have typically focused on the lysosome, a single organelle, current evidence supports that the function of lysosomes cannot be separated from that of the endolysosomal system as a whole. The associated membrane fusion functions of this system play a crucial role in the biodegradation of cerebral ischemia-related products. Here, we review the regulation of and the changes that occur in the endolysosomal system after cerebral ischemia, focusing on the latest research progress on membrane fusion function. Numerous proteins, including N-ethylmaleimide-sensitive factor and lysosomal potassium channel transmembrane protein 175, regulate the function of this system. However, these proteins are abnormally expressed after cerebral ischemic injury, which disrupts the normal fusion function of membranes within the endolysosomal system and that between autophagosomes and lysosomes. This results in impaired "maturation" of the endolysosomal system and the collapse of energy metabolism balance and protein homeostasis maintained by the autophagy-lysosomal pathway. Autophagy is the final step in the endolysosomal pathway and contributes to maintaining the dynamic balance of the system. The process of autophagosome-lysosome fusion is a necessary part of autophagy and plays a crucial role in maintaining energy homeostasis and clearing aging proteins. We believe that, in cerebral ischemic injury, the endolysosomal system should be considered as a whole rather than focusing on the lysosome. Understanding how this dynamic system is regulated will provide new ideas for the treatment of cerebral ischemia.

Dibutyl phthalate causes MC3T3-E1 cell damage by increasing ROS to promote the PINK1/Parkin-mediated mitophagy

Dibutyl phthalate (DBP) is a plasticizer widely used in daily production, which causes serious environmental pollution, and damage to brain, liver, kidney, and lung by producing excessive reactive oxygen species (ROS) after entering the body. DBP can also cause skeletal dysplasia, but it is unclear whether ROS is involved. In addition, overproduction of ROS can activate mitophagy, which is an important mechanism for regulating mitochondrial quality and cell homeostasis. In order to investigate whether DBP can damage MC3T3-E1 cells (osteoblast cell line) and whether ROS and mitophagy are involved, DBP toxicity experiment, Parkin gene silencing experiment, and N-acetylcysteine (NAC) intervention experiment were performed on MC3T3-E1 cells in turn. First, we found that DBP caused MC3T3-E1 cell viability decline and osteogenic dysfunction, accompanied by the overproduction of ROS and the activation of mitophagy. Then, we found that silencing Parkin expression alleviated DBP-induced apoptosis and osteogenic dysfunction of MC3T3-E1 cells. In addition, NAC treatment inhibited the PINK1/Parkin-mediated mitophagy and alleviated the apoptosis and osteogenic dysfunction of MC3T3-E1 cells caused by DBP. Our research results showed that DBP could cause MC3T3-E1 cell damage by increasing ROS to promote the PINK1/Parkin-mediated mitophagy.

Compartmentalized regulation of NAD+ by Di (2-ethyl-hexyl) phthalate induces DNA damage in placental trophoblast

Di (2-ethyl-hexyl) phthalate (DEHP) is a wildly used plasticizer. Maternal exposure to DEHP during pregnancy blocks the placental cell cycle at the G2/M phase by reducing the efficiency of the DNA repair pathways and affects the health of offsprings. However, the mechanism by which DEHP inhibits the repair of DNA damage remains unclear. In this study, we demonstrated that DEHP inhibits DNA damage repair by reducing the activity of the DNA repair factor recruitment molecule PARP1. NAD+ and ATP are two substrates necessary for PARP1 activity. DEHP abated NAD+ in the nucleus by reducing the level of NAD+ synthase NMNAT1 and elevated NAD+ in the mitochondrial by promoting synthesis. Furthermore, DEHP destroyed the mitochondrial respiratory chain, affected the structure and quantity of mitochondria, and decreased ATP production. Therefore, DEHP inhibits PARP1 activity by reducing the amount of NAD+ and ATP, which hinders the DNA damage repair pathways. The supplement of NAD+ precursor NAM can partially rescue the DNA and mitochondria damage. It provides a new idea for the prevention of health problems of offsprings caused by DEHP injury to the placenta.

Arsenic exposure elevated ROS promotes energy metabolic reprogramming with enhanced AKT-dependent HK2 expression

Exposure to inorganic or organic arsenic compounds continues to pose substantial public health concerns for hundreds of millions of people around the globe. Highly exposed individuals are susceptible to various illnesses, including impairments and cancers of the lung, liver, skin and bladder. Long-term exposure to low-dose arsenic has been identified to induce aerobic glycolysis, which contributes to cells aberrant proliferation. However, the mechanism underlying arsenic-induced aerobic glycolysis is still unclear. Here, mtDNA copy number is enhanced in arsenic-exposed populations and a positive correlation between serum HK2 and urinary total arsenic was observed in the individuals with high urine arsenic (≥ 0.032 mg/L). In a rat model of trivalent arsenic (iAs³⁺) exposure, the levels of HK2, NDUFA9 and NDUFB8 were increased in the rats treated with iAs³⁺ daily by gavage for 12 weeks than those in the control rats. Subsequently, in a low-dose arsenic exposure cell model we found that 0.2 μmol/L iAs³⁺ induced aerobic glycolysis to promote L-02 cells proliferation and inhibit apoptosis, in which HK2 played an important role. Further studies showed accumulated ROS determined the metabolic reprogramming via activating AKT and then increasing HK2 expression. On the one hand, activated AKT induced aerobic glycolysis by increasing HK2 to promote L-02 cells viability and DNA synthesis; on the other hand, phosphorylated AKT induced HK2 mitochondrial outer-membrane location with VDAC1 to inhibit apoptosis. Taken together, our results indicated that ROS induced by low-dose arsenic exposure determined energy metabolic reprogramming and acted a critical regulator for AKT-dependent HK2 expression and aerobic glycolysis.

Effects of DEHP, DEHT and DINP Alone or in a Mixture on Cell Viability and Mitochondrial Metabolism of Endothelial Cells In Vitro

Plasticizers are chemicals in high demand, used in a wide range of commercial products. Human are exposed through multiple pathways, from numerous sources, to multiple plasticizers. This is a matter of concern, as it may contribute to adverse health effects. The vascular system carries plasticizers throughout the body and therefore can interact with the endothelium. The aim of the study was to evaluate the in vitro toxicity on endothelial cells by considering the individual and the mixture effects of bis-(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP) or bis-(2-ethylhexyl) terephthalate (DEHT). In this study, their cytotoxicity on HMEC-1 cells was evaluated on cell function (viability, cell counting, total glutathione and intracellular adenosines) and mitochondrial function (mitochondrial respiration). Results showed cellular physiological perturbations induced with all the condition tested, excepted for DEHT. Plasticizers induced a cytotoxicity by targeting mitochondrial respiration, depleting mitochondrial ATP production and increasing glycolytic metabolism. Additionally, delayed effects were observed between the cellular and the mitochondrial parameters. These results suggest that endothelial cells could go through a metabolic adaptation to face plasticizer-induced cellular stress, to effectively maintain their cellular processes. This study provides additional information on the adverse effects of plasticizers on endothelial cells.

Deconvoluting the Complexity of Reactive Oxygen Species (ROS) in Neurodegenerative Diseases

Neurodegenerative diseases (NDs) are becoming a serious public health concern as the world’s population continues to age, demanding the discovery of more effective therapies. Excessive formation of reactive oxygen species (ROS) can result in oxidative stress (OS), which can be regarded as one of the common causes of neurodegenerative diseases (NDs). Thus, in this review, we focus on summarizing the consequences of ROS NDs, while taking the four prevalent NDs as examples, including Alzheimer’s disease (AD), Parkinson’s disease (PD), Amyotrophic lateral sclerosis (ALS), and Huntington’s disease (HD), to illustrate the key signaling pathways and relevant drugs. Together, these findings may shed new light on a field in which ROS-related pathways play a key role; thereby setting the groundwork for the future therapeutic development of neurodegenerative diseases.

Parkin, as a Regulator, Participates in Arsenic Trioxide-Triggered Mitophagy in HeLa Cells

Parkin is a well-established synergistic mediator of mitophagy in dysfunctional mitochondria. Mitochondria are the main target of arsenic trioxide (ATO) cytotoxicity, and the effect of mitophagy on ATO action remains unclear. In this study, we used stable Parkin-expressing (YFP-Parkin) and Parkin loss-of-function mutant (Parkin C431S) HeLa cell models to ascertain whether Parkin-mediated mitophagy participates in ATO-induced apoptosis/cell death. Our data showed that the overexpression of Parkin significantly sensitized HeLa cells to ATO-initiated proliferation inhibition and apoptosis; however, the mutation of Parkin C431S significantly weakened this Parkin-mediated responsiveness. Our further investigation found that ATO significantly downregulated two fusion proteins (Mfn1/2) and upregulated fission-related protein (Drp1). Autophagy was also activated as evidenced by the formation of autophagic vacuoles and mitophagosomes, increased expression of PINK1, and recruitment of Parkin to impaired mitochondria followed by their degradation, accompanied by the increased transformation of LC3-I to LC3-II, increased expression of Beclin1 and decreased expression of P62 in YFP-Parkin HeLa cells. Enhanced mitochondrial fragmentation and autophagy indicated that mitophagy was activated. Furthermore, during the process of mitophagy, the overproduction of ROS implied that ROS might represent a key factor that initiates mitophagy following Parkin recruitment to mitochondria. In conclusion, our findings indicate that Parkin is critically involved in ATO-triggered mitophagy and functions as a potential antiproliferative target in cancer cells.

Acetaldehyde Induces Cytotoxicity via Triggering Mitochondrial Dysfunction and Overactive Mitophagy

Overconsumption of alcohol damages brain tissue and causes cognitive dysfunction. It has been suggested that the neurotoxicity caused by excessive alcohol consumption is largely mediated by acetaldehyde, the most toxic metabolite of ethanol. Evidence shows that acetaldehyde impairs mitochondrial function and induces cytotoxicity of neuronal cells; however, the exact mechanisms are not fully understood. The aim of this study was to investigate the role of mitophagy in acetaldehyde-induced cytotoxicity. It was found that acetaldehyde treatment induced mitophagic responses and caused cytotoxicity in SH-SY5Y cells. The levels of light chain 3 (LC3)-II, Beclin1, autophagy-related protein (Atg) 5 and Atg16L1, PTEN-induced putative kinase (PINK)1, and Parkin were significantly elevated, while the level of p62 was reduced in acetaldehyde-treated cells. Acetaldehyde also promoted the accumulation of PINK1 and Parkin on mitochondria and caused a remarkable decrease of mitochondrial mass. Treatment with autophagy inhibitors prevented the decline of mitochondrial mass and alleviated the cytotoxicity induced by acetaldehyde, suggesting that overactive mitophagy might be an important mechanism contributing to acetaldehyde-induced cytotoxicity. Antioxidant N-acetyl-L-cysteine significantly attenuated the mitophagic responses and alleviated the cytotoxicity induced by acetaldehyde, indicating that oxidative stress was a major mediator of the excessive mitophagy induced by acetaldehyde. Taken together, these findings provided new insights into the role of mitophagy and oxidative stress in acetaldehyde-induced cytotoxicity.

DEHP induces ferroptosis in testes via p38α-lipid ROS circulation and destroys the BTB integrity

Exposure to Di (2-ethylhexyl) phthalate (DEHP) has been associated with toxic effects of the reproductive system. However, the exact mechanism remains to be elucidated. In this study we explored the testicular toxicity induced by DEHP, and the probable molecular mechanism in the process. In vivo, the results demonstrated that DEHP affected testosterone levels and blood-testosterone barrier (BTB) integrity and caused ferroptosis. We further demonstrated that DEHP up-regulated the expression of p38α, p-p38α, p53, p-p53, SAT1, ALOX15. This view has also been confirmed in TM4 cells. After pre-treatment with fer-1 or si-MAPK14, the expression of either p53, p-p53, SAT1 and ALOX15 up-regulated by MEHP was inhibited in vitro. Interestingly, p38α can prevent the accumulation of lipid ROS, and the production of lipid ROS in turn promoted the expression of p38α, thus forming a feedback loop during the ferroptosis. In this process, a vicious cycle consisting of p38α, p53, SAT1, ALOX15, lipid ROS was involved. This study provides new mechanistic insights into DEHP-induced toxicity of the reproductive system.