Rutin mitigates fluoride-induced nephrotoxicity by inhibiting ROS-mediated lysosomal membrane permeabilization and the GSDME-HMGB1 axis involved in pyroptosis and inflammation.

Fluoride is known to induce nephrotoxicity; however, the underlying mechanisms remain incompletely understood. Therefore, this study aims to explore the roles and mechanisms of lysosomal membrane permeabilization (LMP) and the GSDME/HMGB1 axis in fluoride-induced nephrotoxicity and the protective effects of rutin. Rutin, a naturally occurring flavonoid compound known for its antioxidative and anti-inflammatory properties, is primarily mediated by inhibiting oxidative stress and reducing proinflammatory markers. To that end, we established in vivo and in vitro models. In the in vivo study, rats were exposed to sodium fluoride (NaF) throughout pregnancy and up until 2 months after birth. In parallel, we employed in vitro models using HK-2 cells treated with NaF, n-acetyl-L-cysteine (NAC), or rutin. We assessed lysosomal permeability through immunofluorescence and analyzed relevant protein expression via western blotting. Our findings showed that NaF exposure increased ROS levels, resulting in enhanced LMP and increased cathepsin B (CTSB) and D (CTSD) expression. Furthermore, the exposure to NaF resulted in the upregulation of cleaved PARP1, cleaved caspase-3, GSDME-N, and HMGB1 expressions, indicating cell death and inflammation-induced renal damage. Rutin mitigates fluoride-induced nephrotoxicity by suppressing ROS-mediated LMP and the GSDME/HMGB1 axis, ultimately preventing fluoride-induced renal toxicity occurrence and development. In conclusion, our findings suggest that NaF induces renal damage through ROS-mediated activation of LMP and the GSDME/HMGB1 axis, leading to pyroptosis and inflammation. Rutin, a natural antioxidative and anti-inflammatory dietary supplement, offers a novel approach to prevent and treat fluoride-induced nephrotoxicity.

TFEB ameliorates DEHP-induced neurotoxicity by activating GAL3/TRIM16 axis dependent lysophagy and alleviating lysosomal dysfunction.

Di-(2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer with known neurotoxic effects. However, the specific mechanism underlying this neurotoxicity remains unclear. This study aimed to investigate the role of lysosomal function and lysophagy in DEHP-induced neurotoxicity, with a particular focus on the regulatory role of Transcription factor EB (TFEB). To achieve this, we utilized in vitro models of DEHP-exposed SH-SY5Y cells and HT22 cells. Our findings revealed that DEHP exposure led to lysosomal damage and dysfunction. Moreover, we observed impaired autophagic degradation, characterized by elevated levels of LC3II and p62. DEHP treatment downregulated the expression of TFEB, GAL3, and TRIM16, while upregulating the expression of PARP. This led to the inhibition of GAL3/TRIM16 axis dependent lysophagy and ultimately excessive apoptosis in neuronal cells. Importantly, TFEB overexpression alleviated lysosomal dysfunction, activated lysophagy, and mitigated DEHP-induced apoptosis. Overall, our results suggest that DEHP induces not only lysosomal dysfunction, but also inhibits lysophagy through the suppression of GAL3/TRIM16 axis. Consequently, impaired clearance of damaged lysosomes occurs, culminating in neuronal apoptosis. Taken together, our findings highlight the critical role of TFEB in regulating lysophagy and lysosomal function. Furthermore, TFEB may serve as a potential therapeutic target for mitigating DEHP-induced neuronal toxicity.

Correction: Leveraging correlations between variants in polygenic risk scores to detect heterogeneity in GWAS cohorts.

[This corrects the article DOI: 10.1371/journal.pgen.1009015.].

TFE3-mediated impairment of lysosomal biogenesis and defective autophagy contribute to fluoride-induced hepatotoxicity.

Excessive fluoride exposure can cause liver injury, but the specific mechanisms need further investigation. We aimed to explore the role of impaired lysosomal biogenesis and defective autophagy in fluoride-induced hepatotoxicity and its potential mechanisms, focusing on the role of transcription factor E3 (TFE3) in regulating hepatocyte lysosomal biogenesis. To this end, we established a Sprague-Dawley (SD) rat model exposed to sodium fluoride (NaF) and a rat liver cell line (BRL3A) model exposed to NaF. The results showed that NaF exposure diminished liver function and led to apoptosis as well as autophagosome accumulation and impaired autophagic degradation. In addition, NaF exposure caused compromised lysosome biogenesis and decreased lysosomal degradation, and inhibited TFE3 nuclear translocation. Notably, the mTOR inhibitors rapamycin (RAPA) and Ad-TFE3 promoted lysosomal biogenesis and enhanced lysosomal degradation function. Furthermore, RAPA and Ad-TFE3 reduced NaF-induced apoptosis by alleviating impaired autophagic degradation. In conclusion, NaF impairs lysosomal biogenesis by inhibiting TFE3 nuclear translocation, decreasing lysosomal degradation function, resulting in impaired autophagic degradation, and ultimately inducing apoptosis. Therefore, TFE3 may be a promising therapeutic target for fluoride-induced hepatotoxicity.

PRKAA1 induces aberrant mitophagy in a PINK1/Parkin-dependent manner, contributing to fluoride-induced developmental neurotoxicity.

Chronic fluoride exposure can cause developmental neurotoxicity, however the precise mechanisms remain unclear. To explore the mechanism of mitophagy in fluoride-induced developmental neurotoxicity, specifically focusing on PRKAA1 in regulating the PINK1/Parkin pathway, we established a Sprage Dawley rat model with continuous sodium fluoride (NaF) exposure and an NaF-treated SH-SY5Y cell model. We found that NaF exposure increased the levels of LC3-Ⅱ and p62, impaired autophagic degradation, and subsequently blocked autophagic flux. Additionally, NaF exposure increased the expression of PINK1, Parkin, TOMM-20, and Cyt C and cleaved PARP in vivo and in vitro, indicating NaF promotes mitophagy and neuronal apoptosis. Meanwhile, phosphoproteomics and western blot analysis showed that NaF treatment enhanced PRKAA1 phosphorylation. Remarkably, the application of both 3-methyladenosine (3-MA; autophagy inhibitor) and dorsomorphin (DM; AMPK inhibitor) suppressed NaF-induced neuronal apoptosis by restoring aberrant mitophagy. In addition, 3-MA attenuated an increase in p62 protein levels and NaF-induced autophagic degradation. Collectively, our findings indicated that NaF causes aberrant mitophagy via PRKAA1 in a PINK1/Parkin-dependent manner, which triggers neuronal apoptosis. Thus, regulating PRKAA1-activated PINK1/Parkin-dependent mitophagy may be a potential treatment for NaF-induced developmental neurotoxicity.

The inhibition of TRPML1/TFEB leads to lysosomal biogenesis disorder, contributes to developmental fluoride neurotoxicity.

Fluoride is capable of inducing developmental neurotoxicity; regrettably, the mechanism is obscure. We aimed to probe the role of lysosomal biogenesis disorder in developmental fluoride neurotoxicity-specifically, the regulating effect of the transient receptor potential mucolipin 1 (TRPML1)/transcription factor EB (TFEB) signaling pathway on lysosomal biogenesis. Sprague-Dawley rats were given fluoridated water freely, during pregnancy to the parental rats to 2 months after delivery to the offspring. In addition, neuroblastoma SH-SY5Y cells were treated with sodium fluoride (NaF), with or without mucolipin synthetic agonist 1 (ML-SA1) or adenovirus TFEB (Ad-TFEB) intervention. Our findings revealed that NaF impaired learning and memory as well as memory retention capacities in rat offspring, induced lysosomal biogenesis disorder, and decreased lysosomal degradation capacity, autophagosome accumulation, autophagic flux blockade, apoptosis, and pyroptosis. These changes were evidenced by the decreased expression of TRPML1, nuclear TFEB, LAMP2, CTSB, and CTSD, as well as increased expression of LC3-II, p62, cleaved PARP, NLRP3, Caspase1, and IL-1ß. Furthermore, TRPML1 activation and TFEB overexpression both restored TFEB nuclear protein expression and promoted lysosomal biogenesis while enhancing lysosomal degradation capacity, recovering autophagic flux, and attenuating NaF-induced apoptosis and pyroptosis. Taken together, these results show that NaF promotes the progression of developmental fluoride neurotoxicity by inhibiting TRPML1/TFEB expression and impeding lysosomal biogenesis. Notably, the activation of TRPML1/TFEB alleviated NaF-induced developmental neurotoxicity. Therefore, TRPML1/TFEB may be promising markers of developmental fluoride neurotoxicity.

Cross-talk between autophagy and ferroptosis contributes to the liver injury induced by fluoride via the mtROS-dependent pathway.

Fluoride can induce hepatotoxicity, but the mechanisms responsible are yet to be investigated. This study sought to investigate the role and mechanism of mitochondrial reactive oxygen species (mtROS), autophagy, and ferroptosis in fluoride-induced hepatic injury with a focus on the role of mtROS-mediated cross-talk between autophagy and ferroptosis. To this end, an in vivo Sprague-Dawley rat model and in vitro BRL3A cells were exposed to sodium fluoride (NaF). The results revealed that NaF exposure diminished the mitochondrial membrane potential, increased mtROS production and TOMM20 expression, and induced autophagic flux blockage and ferroptosis in vivo and in vitro. Furthermore, the autophagy activator (RAPA) enhanced GPX4 expression while inhibiting ACSL4 expression, reduced the accumulation of ferrous ions in BRL3A cells, and restored lipid peroxidation levels, thus inhibiting ferroptosis. Fer-1, a ferritinase inhibitor, downregulated the expression of LC3-II and p62, increased the number of autolysosomes while decreasing the number of autophagosomes, and alleviated the blockage of autophagic flux by improving autophagic degradation. These results suggest the occurrence of a cross-talk between autophagy and ferroptosis. The mtROS inhibitor (Mito-TEMPO) could alleviate autophagic flux blockage and inhibit ferroptosis in NaF-induced liver injury. In addition, the cross-talk between NaF-induced autophagy and ferroptosis was dependent on the mtROS pathway.

Fluoride Induces Neurocytotoxicity by Disrupting Lysosomal Iron Metabolism and Membrane Permeability.

The detrimental effects of fluoride on neurotoxicity have been widely recorded, yet the detailed mechanisms underlying these effects remain unclear. This study explores lysosomal iron metabolism in fluoride-related neurotoxicity, with a focus on the Steap3/TRPML1 axis. Utilizing sodium fluoride (NaF)-treated human neuroblastoma (SH-SY5Y) and mouse hippocampal neuron (HT22) cell lines, our research demonstrates that NaF enhances the accumulation of ferrous ions (Fe2+) in these cells, disrupting lysosomal iron metabolism through the Steap3/TRPML1 axis. Notably, NaF exposure upregulated ACSL4 and downregulated GPX4, accompanied by reduced glutathione (GSH) levels and superoxide dismutase (SOD) activity and increased malondialdehyde (MDA) levels. These changes indicate increased vulnerability to ferroptosis within neuronal cells. The iron chelator deferoxamine (DFO) mitigates this disruption. DFO binds to lysosomal Fe2+ and inhibits the Steap3/TRPML1 axis, restoring normal lysosomal iron metabolism, preventing lysosomal membrane permeabilization (LMP), and reducing neuronal cell ferroptosis. Our findings suggest that interference in lysosomal iron metabolism may mitigate fluoride-induced neurotoxicity, underscoring the critical role of the Steap3/TRPML1 axis in this pathological process.

Elevated Serum Copper, Zinc, Selenium, and Lowered α-Klotho Associations: Findings from NHANES 2011-2016 Dataset.

The α-Klotho is crucial for human health and longevity. However, the relationship between trace elements and α-Klotho levels needs further investigation. We aimed to explore the relationship between serum levels of selenium (Se), copper (Cu), and zinc (Zn), and serum α-Klotho levels. We analyzed 2138 samples from the 2011-2016 National Health and Nutrition Examination Survey, and the weighted linear regression, WQS, and qgcomp models were utilized to evaluate the effects of these elements on serum α-Klotho levels, individually and combined. A negative correlation was observed between serum Cu concentration and serum α-Klotho levels (ß = - 0.128, 95% CI - 0.196, - 0.059), with each increase in Cu concentration grade showing a gradual decrease in serum α-Klotho levels (Ptrend = 0.002). The WQS model exhibited a negative correlation between the combined effect of Se, Cu, and Zn and serum α-Klotho levels (ß = - 0.035, 95%CI - 0.060, - 0.010), consistently in males (ß = - 0.038 (- 0.059, - 0.017)) and in the 40-49 age group (ß = - 0.059, 95% CI - 0.119, - 0.012). The qgcomp model mirrored these findings, showing a negative correlation in the combined effect index of Se, Cu, and Zn with serum α-Klotho levels (ß = - 0.027, 95% CI - 0.047, - 0.006), consistent in females (ß = - 0.032, 95% CI - 0.061, - 0.004) and in individuals with BMI ≥ 25 (ß = - 0.030, 95% CI - 0.054, - 0.006), and in the 40-49 age group (ß = - 0.047, 95% CI - 0.088, - 0.006). Elevated serum Cu levels may be associated with lower serum α-Klotho levels. The combined effect of serum Se, Cu, and Zn shows a negative correlation with serum α-Klotho levels, with Cu contributing the most. Our findings provide significant insights into assessing the role of trace nutrients in maintaining human health.

Age, Gender, and BMI Modulate the Hepatotoxic Effects of Brominated Flame Retardant Exposure in US Adolescents and Adults: A Comprehensive Analysis of Liver Injury Biomarkers.

Brominated flame retardants (BFRs), commonly found in consumer products, have been identified as potential hazards to liver function. While the individual effects of specific BFRs are somewhat understood, there is limited evidence on how mixtures of these chemicals, especially when influenced by demographic factors, interact to affect liver function. This study utilized data from 10,828 participants aged 12 and above from the National Health and Nutrition Examination Survey (2005-2016) to investigate the associations between BFRs (both individually and in combinations) and biomarkers of liver injury. The study focused on how age, gender, and body mass index (BMI) modify modulate these effects. Multivariate linear regression, restricted cubic spline function, weighted quantile sum (WQS) regression, and quantile g-computation (qgcomp) models were used to analyze the linear, non-linear, and joint associations between BFR levels and liver function parameters. We found positive associations between the mixed BFRs index and AST, ALT, GGT, ALP, and TBIL levels and a negative association with ALB levels. PBDE28, PBDE47, and PBB153 consistently contributed to the top weight in both the WQS and qgcomp models. Most critically, the study demonstrated that the relationship between co-exposure to BFRs and liver function parameters was modified by age, gender, and BMI. Therefore, our study highlights the importance of considering demographic diversity in assessing the risk of BFR-induced liver damage and supports the implementation of tailored preventive and intervention strategies.

Independent and combined associations of urinary arsenic exposure and serum sex steroid hormones among 6-19-year old children and adolescents in NHANES 2013-2016.

Arsenic exposure may disrupt sex steroid hormones, causing endocrine disruption. However, human evidence is limited and inconsistent, especially for children and adolescents. To evaluate the independent and combined associations between arsenic exposure and serum sex steroid hormones in children and adolescents, we conducted a cross-sectional analysis of data from 1063 participants aged 6 to 19 years from the 2013-2016 National Health and Nutrition Examination Survey (NHANES). Three urine arsenic metabolites were examined, as well as three serum sex steroid hormones, estradiol (E2), total testosterone (TT), and sex hormone-binding globulin (SHBG). The ratio of TT to E2 (TT/E2) and the free androgen index (FAI) generated by TT/SHBG were also assessed. Linear regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) were used to evaluate the associations of individual or arsenic metabolite combinations with sex steroid hormones by gender and age stratification. Positive associations were found between total arsenic and arsenic metabolites with TT, E2, and FAI. In contrast, negative associations were found between arsenic metabolites and SHBG. Furthermore, there was an interaction after gender-age stratification between DMA and SHBG in female adolescents. Notably, based on the WQS and BKMR model results, the combined association of arsenic and its metabolites was positively associated with TT, E2, and FAI and negatively associated with SHBG. Moreover, DMA and MMA dominated the highest weights among the arsenic metabolites. Overall, our results indicate that exposure to arsenic, either alone or in mixtures, may alter sex steroid hormone levels in children and adolescents.