FUNDC1-mediated mitophagy triggered by mitochondrial ROS is partially involved in 1-nitropyrene-evoked placental progesterone synthesis inhibition and intrauterine growth retardation in mice

1-nitropyrene triggers trophoblast dysfunction via EMPs-mediated ferroptosis through Glutathione peroxidase 4

1-Nitropyrene (1-NP), a prevalent environmental pollutant, poses significant risks to vascular and placental health. This study demonstrates that 1-NP induces vascular endothelial dysfunction by dose-dependently reducing human umbilical vein endothelial cell (HUVEC) viability, inhibiting proliferation, promoting apoptosis, and impairing tube formation. Notably, endothelial microparticles (EMPs) isolated from 1-NP-treated HUVECs (N-EMPs) exhibited distinct biological effects compared to control EMPs (C-EMPs). N-EMPs suppressed trophoblast viability, proliferation, invasion, and migration, correlating with N-cadherin downregulation and E-cadherin upregulation. Mechanistically, ferroptosis emerged as the primary driver of N-EMPs-induced trophoblast dysfunction, evidenced by reactive oxygen species (ROS) accumulation, glutathione depletion, elevated malondialdehyde and Fe²⁺ levels, and mitochondrial oxidative stress. Crucially, glutathione peroxidase 4 (GPX4) was identified as a central regulator, with its expression significantly downregulated by N-EMPs. Overexpression of GPX4 reversed ferroptosis markers (restoring GSH/SOD, reducing MDA/Fe²⁺) and rescued trophoblast viability, migration, and invasiveness. These findings establish a previously unrecognized pathogenic cascade wherein 1-NP triggers endothelial injury, releasing cytotoxic EMPs that propagate ferroptosis-dependent trophoblast dysfunction via GPX4 suppression. The central role of EMPs as mediators of environmental pollutant toxicity highlights their potential as biomarkers and therapeutic targets for mitigating placental developmental disorders caused by 1-NP exposure.

Effect of 1-nitropyrene exposure on the biological behavior of trophoblast cells

1-nitropyrene (1-NP) is a toxic component of PM2.5 that adversely affects human health, especially pregnant women; however, the mechanisms are still unclear. This study aims to explore the mechanisms by which 1-NP influences trophoblast cell behaviors. HTR8/Svneo cells were treated by different concentrations of 1-NP (0, 5, 10, 20 μM) to assess clonogenic, invasive, and migratory abilities. Western blot analysis was used to assess the expression of EMT and Wnt/β-catenin pathway proteins. 1-NP significantly inhibited HTR8/Svneo cell clonogenic ability, especially at 10 μM and 20 μM (P < 0.01). Invasiveness decreased by 68.44 % at 5 μM (P < 0.05), and migration was significantly inhibited at 10 μM and 20 μM (P < 0.05). Western blot revealed increased E-cadherin and decreased Vimentin (P < 0.01), elevated β-catenin (P < 0.05), and reduced APC (P < 0.01). In summary, 1-NP impacts trophoblast cell clonogenicity, invasion, and migration by modulating EMT and Wnt/β-catenin pathways, providing novel insights into its biological effects on trophoblast cells.

Mitochondrial ROS-associated integrated stress response is involved in arsenic-induced blood-testis barrier disruption and protective effect of melatonin

Arsenic (As) is an environmental metalloid. Previous studies have demonstrated that As exposure resulted in decline of sperm quality. This study aimed to investigate the impact of exposure to As on blood-testis barrier (BTB) in a mouse model. Four-week-old male mice were exposed to NaAsO2 (1 or 15 mg/L) for 6 weeks. Our results found that NaAsO2 exposure disrupted the BTB and reduced sperm counts in adult mice. NaAsO2 activated the integrated stress response (ISR) and downregulated barrier junction protein in mouse testes and Sertoli cells. Ribosome profiling sequencing (Ribo-seq) and Ribosome-nascent chain complex-bound mRNA qPCR (RNC-qPCR) showed that translational efficiency of N-cadherin and ZO-1, two key barrier junction proteins, was reduced in NaAsO2-treated Sertoli cells. Mechanistically, NaAsO2 exposure reduced SIRT3 protein via proteasomal degradation, thereby resulting in mitochondrial dysfunction and excess mitochondrial ROS (mtROS) generation in Sertoli cells. Melatonin alleviated NaAsO2-induced mitochondrial dysfunction and mtROS upregulation via reducing SOD2 acetylation in Sertoli cells. Moreover, melatonin antagonized NaAsO2-induced ISR, barrier junction proteins downregulation and barrier function impairment in Sertoli cells. Accordingly, melatonin attenuated NaAsO2-evoked BTB disruption and sperm count reduction in adult mice. These results suggest that mitochondrial dysfunction-associated translational inhibition of barrier junction proteins is involved in As-mediated BTB disruption and sperm quality decline.

Mitochondrial malfunction-initiated Leydig cell premature senescence partially participates in 1-nitropyrene-evoked downregulation of steroidogenic synthases in testes

Serum testosterone (T) in males has been declining during the past decades. The previous reports found that 1-nitropyrene (1-NP) exposure suppressed testicular T synthesis. The purpose of the current study was to further explore whether premature senescence participates in 1-NP-triggered reduction of testicular T synthesis. Adult male mice were orally exposed to 1-NP (0, 100, and 500 μg/kg) daily for 14 days. Serum and testicular T contents were diminished in 1-NP-administered mice. Mitochondria-located steroidogenic synthases, including StAR, CYP11A1, and 3βHSD1, were downregulated in 1-NP-administered mouse testes and MLTC-1 cells. Mechanistically, 1-NP exposure increased acetylation modification of mitochondrial steroidogenic synthases by inhibiting the enzymatic activity of SIRT3, an NAD+-dependent deacetylase. Supplementing NAD + precursor and Sirt3 overexpression relieved 1-NP-triggered reduction of steroidogenic synthase levels in mouse testes and MLTC-1 cells. By contrast, Sirt3 silencing aggravated 1-NP-evoked acetylation and reduction of steroidogenic synthase levels in MLTC-1 cells. Further experiments demonstrated that 1-NP exposure caused mitochondrial malfunction and premature senescence in mouse testes and MLTC-1 cells. Supplementation with mitochondria-directed antioxidant mitoquinone (MitoQ) prevented 1-NP-evoked Leydig cell premature senescence and downregulation of testicular steroidogenic synthases. These results suggest that mitochondrial malfunction-initiated Leydig cell premature senescence may partially participate in 1-NP-evoked reduction of steroidogenic synthase levels in testes.

Exposure to 1-nitropyrene after weaning induces anxiety-like behavior partially by inhibiting steroid hormone synthesis in prefrontal cortex

1-Nitropyrene (1-NP) is a neurodevelopmental toxicant. This study was to evaluate the impact of exposure to 1-NP after weaning on anxiety-like behavior. Five-week-old mice were administered with 1-NP (0.1 or 1 mg/kg) daily for 4 weeks. Anxiety-like behaviour was measured using elevated-plus maze (EPM) and open field test (OFT). In EPM test, time spending in open arm and times entering open arm were reduced in 1-NP-treated mice. In OFT test, time spent in the center region and times entering the center region were diminished in 1-NP-treated mice. Prefrontal dendritic length and number of dendrite branches were decreased in 1-NP-treated mice. Prefrontal PSD95, an excitatory postsynaptic membrane protein, and gephyrin, an inhibitory postsynaptic membrane protein, were downregulated in 1-NP-treated mice. Further analysis showed that peripheral steroid hormones, including serum testosterone (T) and estradiol (E2), testicular T, and ovarian E2, were decreased in 1-NP-treated mice. Interestingly, T and E2 were diminished in 1-NP-treated prefrontal cortex. Prefrontal T and E2 synthases were diminished in 1-NP-treated mice. Mechanistically, GCN2-eIF2α, a critical pathway that regulates ribosomal protein translation, was activated in 1-NP-treated prefrontal cortex. These results indicate that exposure to 1-NP after weaning induces anxiety-like behaviour partially by inhibiting steroid hormone synthesis in prefrontal cortex.

The mitochondria-targeted antioxidant MitoQ ameliorates inorganic arsenic-induced DCs/Th1/Th2/Th17/Treg differentiation partially by activating PINK1-mediated mitophagy in murine liver

Inorganic arsenic is a well-established environmental toxicant linked to acute liver injury, fibrosis, and cancer. While oxidative stress, pyroptosis, and ferroptosis are known contributors, the role of PTEN-induced kinase 1 (PINK1)-mediated mitophagy in arsenic-induced hepatic immunotoxicity remains underexplored. Our study revealed that acute arsenic exposure prompts differentiation of hepatic dendritic cells (DCs) and T helper (Th) 1, Th2, Th17, and regulatory T (Treg) cells, alongside increased transcription factors and cytokines. Inorganic arsenic triggered liver redox imbalance, leading to elevated alanine transaminase (ALT), hydrogen peroxide (H2O2), malondialdehyde (MDA), and activation of nuclear factor erythroid 2-related factor (Nrf2)/heme oxygenase-1 (HO-1) pathway. PINK1-mediated mitophagy was initiated, and its inhibition exacerbates H2O2 accumulation while promoting DCs/Th1/Th2/Treg differentiation in the liver of arsenic-exposed mice. Mitoquinone (MitoQ) pretreatment relieved arsenic-induced acute liver injury and immune imbalance by activating Nrf2/HO-1 and PINK1-mediated mitophagy. To our knowledge, this is the first report identifying PINK1-mediated mitophagy as a protective factor against inorganic arsenic-induced hepatic DCs/Th1/Th2 differentiation. This study has provided new insights on the immunotoxicity of inorganic arsenic and established a foundation for exploring preventive and therapeutic strategies targeting PINK1-mediated mitophagy in acute liver injury. Consequently, the application of mitochondrial antioxidant MitoQ may offer a promising treatment for the metalloid-induced acute liver injury.

An integral role of mitochondrial function in the pathophysiology of preeclampsia

Preeclampsia (PE) is associated with high maternal and perinatal morbidity and mortality. The development of effective treatment strategies remains a major challenge due to the limited understanding of the pathogenesis. In this review, we summarize the current understanding of PE research, focusing on the molecular basis of mitochondrial function in normal and PE placentas, and discuss perspectives on future research directions. Mitochondria integrate numerous physiological processes such as energy production, cellular redox homeostasis, mitochondrial dynamics, and mitophagy, a selective autophagic clearance of damaged or dysfunctional mitochondria. Normal placental mitochondria have evolved innovative survival strategies to cope with uncertain environments (e.g., hypoxia and nutrient starvation). Cytotrophoblasts, extravillous trophoblast cells, and syncytiotrophoblasts all have distinct mitochondrial morphology and function. Recent advances in molecular studies on the spatial and temporal changes in normal mitochondrial function are providing valuable insight into PE pathogenesis. In PE placentas, hypoxia-mediated mitochondrial fission may induce activation of mitophagy machinery, leading to increased mitochondrial fragmentation and placental tissue damage over time. Repair mechanisms in mitochondrial function restore placental function, but disruption of compensatory mechanisms can induce apoptotic death of trophoblast cells. Additionally, molecular markers associated with repair or compensatory mechanisms that may influence the development and progression of PE are beginning to be identified. However, contradictory results have been obtained regarding some of the molecules that control mitochondrial biogenesis, dynamics, and mitophagy in PE placentas. In conclusion, understanding how the mitochondrial morphology and function influence cell fate decisions of trophoblast cells is an important issue in normal as well as pathological placentation biology. Research focusing on mitochondrial function will become increasingly important for elucidating the pathogenesis and effective treatment strategies of PE.