Multi-omics analyses reveal the mechanisms of Arsenic-induced male reproductive toxicity in mice

ATF3 as a response factor to regulate Cd-induced reproductive damage by activating the NRF2/HO-1 ferroptosis pathway

Cadmium (Cd) has garnered significant attention due to reproductive toxicity in inducing ferroptosis. However, the specific mechanisms underlying Cd-induced germ cell ferroptosis remain poorly understood. This study aimed to systematically explore the molecular mechanisms of germ cell ferroptosis by investigating differential changes in transcription factors and proteins in male mice treated orally with CdCl2 (0.5 g/L) reaching postnatal day 60, alongside Leydig cell (TM3) and Sertoli cell (TM4) lines. Results demonstrated that Cd exposure led to increased iron overload and oxidative stress in mouse testes, disrupted intracellular mitochondrial morphology characteristic of ferroptosis. RNA sequencing revealed significant upregulation of Atf3 and Hmox1 in Cd-exposed germ cells, along with increased expression of ATF3 and HO-1. Intervention in ferroptosis or HO-1 effectively rescued cells from Cd-induced mortality by breaking the detrimental cycle between lipid peroxidation and HO-1 activation. Further findings showed that NRF2 and HO-1 expression was notably elevated upon ATF3 overexpression in TM3 and TM4 cells, activating the Keap1-Nrf2 pathway and triggering ferroptosis in testes, whereas NRF2 and HO-1 expression levels were reversed when ATF3 was silenced. This study provides novel insights into ATF3-mediated NRF2/HO-1 signaling in Cd-induced mitochondrial ferroptosis in testes, shedding light on the mechanisms underlying Cd-induced ferroptosis and testicular injury.

Selenium Improves Arsenic-Induced Male Reproductive Dysfunction by Regulating H3K14ac Level

Arsenic exposure has been known to be associated with male reproduction injury. Exploring the antidote of arsenic and ascertaining proper dose of antidote are important for detoxifying the male reproductive toxicity of arsenic. Selenium, which is essential for the male reproduction and spermatogenesis, can alleviate the toxicity of many environmental toxins, such as metals, and fluoride (F). Selenium relieves arsenic-induced reductions in spermatogenesis index and testicular function marker enzymes via promoting the antioxidative ability of rats. Our previous study has found that arsenic can induce male reproductive toxicity by affecting the level of H3K14ac in the testis, so we further investigate whether selenium can antagonize arsenic-induced male reproductive toxicity through the H3K14ac pathway and ascertain the appropriate dose of selenium. The results show that selenium intervention reduces the accumulation of arsenic in rat testis probably attributing to promote the excretion of arsenic from rat, then improves the testis injury induced by arsenic. Selenium intervention enhances sperm quality, testosterone level, and expression of steroidogenic genes by regulating H3K14ac level and expression of its associated enzymes (KAT2A, BAZ2A, and HDAC6), and thus alleviates the male reproductive toxicity of arsenic, and the proper dose of Se for mitigating arsenic male reproductive toxicity is 1 mg/kg.

Perfluorohexanesulfonic Acid (PFHxS) Impairs Lipid Homeostasis in Zebrafish Larvae through Activation of PPARα

Perfluorohexanesulfonic acid (PFHxS), an emerging short-chain per- and polyfluoroalkyl substance, has been frequently detected in aquatic environments. Adverse outcome pathway studies have shown that perfluorinated compounds impair lipid homeostasis through peroxisome proliferator activated receptors (PPARs). However, many of these studies were performed at high concentrations and may thus be a result of overt toxicity. To better characterize the molecular and key events of PFHxS to biota, early life-stage zebrafish (Danio rerio) were exposed to concentrations detected in the environment (0.01, 0.1, 1, and 10 μg/L). Lipidomic and transcriptomic evaluations were integrated to predict potential molecular targets. PFHxS significantly impaired lipid homeostasis by the dysregulation of glycerophospholipids, fatty acyls, glycerolipids, sphingolipids, prenol lipids, and sterol lipids. Informatic analyses of the lipidome and transcriptome indicated alterations of the PPAR signaling pathway, with downstream changes to retinol, linoleic acid, and glycerophospholipid metabolism. To assess the role of PPARs, potential binding of PFHxS to PPARs was predicted and animals were coexposed to a PPAR antagonist (GW6471). Molecular simulation indicated PFHxS had a 27.1% better binding affinity than oleic acid, an endogenous agonist of PPARα. Antagonist coexposures rescued impaired glycerophosphocholine concentrations altered by PFHxS. These data indicate PPARα activation may be an important molecular initiating event for PFHxS.

RAB13 regulates macrophage polarization in sepsis

To select the core target (RAB13) in sepsis patients' peripheral blood and investigate its molecular functions and possible mechanisms. The peripheral blood of sepsis patients (n = 21) and healthy individuals (n = 9) within 24 h after admission were collected for RNA-seq, and differential gene screening was performed by iDEP online analysis software (P < 0.01; log2FC ≥ 2) and enrichment analysis, the potential core target RAB13 was screened out. The association between RAB13 expression and sepsis severity was explored using multiple datasets in the GEO database, and survival analysis was conducted. Subsequently, peripheral blood mononuclear cells (PBMCs) from sepsis and control groups were isolated, and 10 × single-cell sequencing was used to identify the main RAB13-expressing cell types. Finally, LPS was used to stimulate THP1 cells to construct a sepsis model to explore the function and possible mechanism of RAB13. We found that RAB13 was a potential core target, and RAB13 expression level was positively associated with sepsis severity and negatively correlated with survival based on multiple public datasets. A single-cell sequencing indicated that RAB13 is predominantly localized in monocytes. Cell experiments validated that RAB13 is highly expressed in sepsis, and the knockdown of RAB13 promotes the polarization of macrophages towards the M2 phenotype. This mechanism may be associated with the ECM-receptor interaction signaling pathway. The upregulation of RAB13 in sepsis patients promotes the polarization of M2-like macrophages and correlates positively with the severity of sepsis.

Sodium arsenite impairs sperm quality via downregulating the ZMYND15 and ZMYND10

Zinc finger MYND-type containing 15 (ZMYND15) has been documented to play important roles in spermatogenesis, and mutants contribute to recessive azoospermia, severe oligozoospermia, non-obstructive azoospermia, teratozoospermia, even male infertility. ZMYND10 is involved in sperm motility. Whether environmental pollutants impair male fertility via regulating the expression of ZMYND15 and ZMYND10 has not been studied. Arsenic exposure results in poor sperm quality and male infertility. In order to investigate whether arsenic-induced male reproductive toxicity is related to the expression of ZMYND15, ZMYND10 and their target genes, we established a male rat model of sodium arsenite exposure-induced reproductive injury, measured sperm quality, serum hormone levels, mRNA and protein expressions of intratesticular ZMYND15 and ZMYND10 as well as their target genes. The results showed that, in addition to the increased mRNA expression of Tnp1, sodium arsenite exposure reduced sperm quality, serum hormone levels, and mRNA and protein expression of intratesticular ZMYND15 and ZMYND10 and their target genes in male rats compared with the control group (p < .05). Therefore, our study first showed that the environmental pollutant arsenic impairs sperm quality in male rats by reducing the expression of ZMYND10 and ZMYND15 and their regulatory genes, which provides a possible diagnostic marker for environmental pollutants-induced male infertility.

Diquat causes mouse testis injury through inducing heme oxygenase-1-mediated ferroptosis in spermatogonia

Diquat dibromide (DQ) is a globally used herbicide in agriculture, and its overuse poses an important public health issue, including male reproductive toxicity in mammals. However, the effects and molecular mechanisms of DQ on testes are limited. In vivo experiments, mice were intraperitoneally injected with 8 or 10 mg/kg/ day of DQ for 28 days. It has been found that heme oxygenase-1 (HO-1) mediates DQ-induced ferroptosis in mouse spermatogonia, thereby damaging testicular development and spermatogenesis. Histopathologically, we found that DQ exposure caused seminiferous tubule disorders, reduced germ cells, and increased sperm malformation, in mice. Reactive oxygen species (ROS) staining of frozen section and transmission electron microscopy (TEM) displayed DQ promoted ROS generation and mitochondrial morphology alterations in mouse testes, suggesting that DQ treatment induced testicular oxidative stress. Subsequent RNA-sequencing further showed that DQ treatment might trigger ferroptosis pathway, attributed to disturbed glutathione metabolism and iron homeostasis in spermatogonia cells in vitro. Consistently, results of western blotting, measurements of MDA and ferrous iron, and ROS staining confirmed that DQ increased oxidative stress and lipid peroxidation, and accelerated ferrous iron accumulation both in vitro and in vivo. Moreover, inhibition of ferroptosis by deferoxamine (DFO) markedly ameliorated DQ-induced cell death and dysfunction. By RNA-sequencing, we found that the expression of HO-1 was significantly upregulated in DQ-treated spermatogonia, while ZnPP (a specific inhibitor of HO-1) blocked spermatogonia ferroptosis by balancing intracellular iron homeostasis. In mice, administration of the ferroptosis inhibitor ferrostatin-1 effectively restored the increase of HO-1 levels in the spermatogonia, prevented spermatogonia death, and alleviated the spermatogenesis disorders induced by DQ. Overall, these findings suggest that HO-1 mediates DQ-induced spermatogonia ferroptosis in mouse testes, and targeting HO-1 may be an effective protective strategy against male reproductive disorders induced by pesticides in agriculture.

Resveratrol alleviates inorganic arsenic-induced ferroptosis in chicken brain via activation of the Nrf2 signaling pathway

Inorganic arsenic (iAs) is a well-recognized environmental pollutant that induces severe brain injury in humans and animals. The antioxidant, anti-inflammatory, and anti-ferroptotic effects of resveratrol (Res) were demonstrated in multiple animal experiments. In order to investigate the protective effect of Res on iAs-induced chicken brain injury, the 40 chickens (19-d-old, female) brain injury model was established by oral administration of iAs (30 mg/L NaAsO2) for 6 weeks. All chickens had free access to both food and water during the experiment. The biochemical indices, hematoxylin-eosin staining, and related protein levels of oxidative stress, inflammation and ferroptosis were then determined. Our results indicated that Res (1000 mg/kg) alleviated the iAs-induced brain injury after 6 weeks of oral administration, primarily by reducing the interleukin-1β mRNA expression and nuclear factor kappa B and malondialdehyde level, and increasing the antioxidant enzyme activity and the mRNA expression of nuclear factor erythroid 2-related factor 2 (Nrf2). Taken together, our study demonstrates that Res effectively inhibits iAs-induced oxidative stress and ferroptosis by mediating the Nrf2 signaling pathway, thereby alleviating iAs-induced brain injury in chickens. This is the first time that the amelioration effects of Res on the iAs-induced brain have been investigated from multiple perspectives.

A regulatory module comprising G3BP1-FBXL5-IRP2 axis determines sodium arsenite-induced ferroptosis

Arsenic contamination is extremely threatening to the global public health. It was reported that sodium arsenite exposure induces serious kidney injury. However, the underlying mechanism is unclear. Ferroptosis is a newly characterized form of iron-dependent programmed cell death, which is implicated in the pathogenesis of various human diseases, including kidney injury. The lethal accumulation of iron-catalyzed lipid peroxidation is the fundamental biochemical characteristic of ferroptosis. Herein we report that sodium arsenite exposure initiates ferroptosis in mammalian HEK293, MEF and HT1080 cells, and induces ferroptosis-associated acute kidney injury in mice. RNA-binding protein G3BP1, the switch component of stress granules, is indispensable for sodium arsenite-induced ferroptosis in a stress granule-independent manner. Mechanistically, G3BP1 stabilizes IRP2, the master regulator of cellular iron homeostasis, through binding to and suppressing the translation of FBXL5 mRNA, which encodes the E3 ligase component to mediate IRP2 ubiquitination and proteasomal degradation. Sodium arsenite intoxication expedites this G3BP1-FBXL5-IRP2 axis and elevates cellular labile free iron, which is responsible for sodium arsenite exposure-induced lipid peroxidation and ferroptotic cell death. In summary, this study highlights a regulatory module comprising G3BP1-FBXL5-IRP2 axis in determining sodium arsenite-induced ferroptosis and ferroptosis-associated acute kidney injury in mice.

Associations of exposure to ambient fine particulate matter constituents from different pollution sources with semen quality: Evidence from a prospective cohort

The association between ambient fine particulate matter (PM2.5) exposure and semen quality remains inconclusive, possibly due to variations in pollution sources and PM2.5 compositions. Studies investigating the constituents of PM2.5 have been hindered by small sample sizes, and research exploring the relationships between PM2.5 pollution sources and semen quality is lacking. To address this gap, we conducted a comprehensive study based on the Anhui prospective assisted reproduction cohort to evaluate the associations between semen quality and the constituents and pollution sources of PM2.5. This study included 9013 semen samples from 4417 males in the urban districts of Hefei. The median concentrations of PM2.5 constituents, including eight metals and four water-soluble ions (WSIs), were measured for seven days per month at two monitoring stations during the 0-90-day exposure window. A linear mixed-effects model, weighted quantile sum regression, and positive matrix factorisation were used to evaluate the associations of the constituents and pollution sources of PM2.5 with semen quality. The results showed that exposure to PM2.5-bound metals (antimony, arsenic, cadmium, lead, and thallium) and WSIs (sulphate and chloride) were negatively associated with semen quality parameters. Moreover, mixtures of PM2.5-bound metals and WSIs were negatively associated with semen quality. Additionally, PM2.5 derived from traffic emissions was negatively associated with semen quality. In summary, our study revealed that ambient PM2.5 and its constituents, especially metals, were negatively associated with semen quality. Antimony, lead, and thallium emerged as the primary contributors to toxicity, and PM2.5 from traffic emissions was associated with decreased semen quality. These findings have important public health implications for the management of PM2.5 pollution in the context of male reproductive health.

Transcriptome and proteome analyses reveal the mechanisms involved in polystyrene nanoplastics disrupt spermatogenesis in mice

Nanoplastics have been demonstrated to be reproductively toxic to mammals. However, the mechanisms of nanoplastics induce reproductive damage in mammals, especially their effects on spermatogenesis, remain elusive. Herein, we explored the effects and underlying mechanisms of polystyrene nanoplastics (PS-NPs) on the testicular development of male mice after 28 days of exposure, representing the first systematic study of PS-NPs-induced male reproductive injury by integrating histomorphology, transcriptomics and proteomics. PS-NPs decreased the sperm concentration, sperm motility, and disrupted the structure of the seminiferous tubules of the mice. Besides, transcriptome and proteome analyses revealed that PS-NPs disrupted spermatogenesis by inhibiting the transcription of Prm3/Tnp1/Aurkc/Mea1/Mettl14 and the expression of Pmfbp1/Ggn/Fsip2. Furthermore, PS-NPs enabled Hsd3b5 protein expression to reduce dihydrotestosterone levels, and affected sperm flagellar assembly by decreasing the expression of Dnah8/Tekt5/Rsph6a. Moreover, PS-NPs induced testicular cell apoptosis by up-regulating the expression of cathepsins (B/F/H). In addition, PS-NPs destroyed tight junctions by reducing the expression of the Claudin family (3/5/15). In conclusion, PS-NPs can disrupt spermatogenesis by altering the expression patterns of transcriptome and proteome, inducing testicular cell apoptosis and destroying tight junctions.

Arsenic and polystyrene-nano plastics co-exposure induced testicular toxicity: Triggers oxidative stress and promotes apoptosis and inflammation in mice

Co-existing of polystyrene-nano plastics (PSNPs) and arsenic (As) in the environment caused a horrendous risk to human health. However, the potential mechanism of PSNPs and As combination induced testicular toxicity in mammals has not been elucidated. Therefore, we first explore the testicular toxicity and the potential mechanism in male Kunming mice exposed to As or/and PSNPs. Results revealed that compared to the As or PSNPs group, the combined group showed more significant testicular toxicity. Specifically, As and PSNPs combination induced irregular spermatozoa array and blood-testis barrier disruption. Simultaneously, As and PSNPs co-exposure also exacerbated oxidative stress, including increasing the MDA content, and down-regulating expression of Nrf-2, HO-1, SOD-1, and Trx. PSNPs and As combination also triggered testicular apoptosis, containing changes in apoptotic factors (P53, Bax, Bcl-2, Cytc, Caspase-8, Caspase-9, and Caspase-3). Furthermore, co-exposed to As and PSNPs aggravated inflammatory damage characterized by targeted phosphorylation of NF-κB and degradation of I-κB. In summary, our results strongly confirmed As + PSNPs co-exposure induced the synergistic toxicity of testis through excessive oxidative stress, apoptosis, and inflammation, which could offer a new sight into the mechanism of environmental pollutants co-exposure induced male reproductive toxicity.

Phenylbutyrate and Dichloroacetate Enhance the Liquid-Stored Boar Sperm Quality via PDK1 and PDK3

Artificial insemination (AI) with liquid-stored semen is the most prevalent and efficient assisted reproduction technique in the modern pork industry. Pyruvate dehydrogenase complex component X (PDHX) was demonstrated to be associated with sperm metabolism and affected the boar sperm viability, motility, and fertility. Pyruvate Dehydrogenase Kinases (PDKs) are the key metabolic enzymes that regulate pyruvate dehydrogenase complex (PDHC) activity and also the conversion from glycolysis to oxidative phosphorylation. In the present study, two PDK inhibitors, Dichloroacetate (DCA) and Phenylbutyrate (4-PBA), were added to an extender and investigated to determine their regulatory roles in liquid-stored boar sperm at 17 °C. The results indicated that PDK1 and PDK3 were predominantly located at the head and flagella of the boar sperm. The addition of 2 mM DCA and 0.5 mM 4-PBA significantly enhanced the sperm motility, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), and ATP content. In addition, DCA and 4-PBA exerted their effects by inhibiting PDK1 and PDK3, respectively. In conclusion, DCA and 4-PBA were found to regulate the boar sperm metabolic activities via PDK1 and PDK3. These both can improve the quality parameters of liquid-stored boar sperm, which will help to improve and optimize liquid-stored boar semen after their addition in the extender.

Transcriptome-based analysis of the toxic effects of aluminum chloride exposure on spermatocytes

Aluminum chloride (AlCl3) exposure is pervasive in our daily lives. Numerous studies have demonstrated that exposure to AlCl3 can lead to male reproductive toxicity. However, the precise mechanism of action remains unclear. The objective of this study is to investigate the mechanism of aluminum-induced toxicity by analyzing the alterations in the global transcriptome gene profile of mouse spermatocytes (GC-2spd cells) exposed to AlCl3. GC-2spd cells were exposed to concentrations of 0, 1, 2, and 4 mM AlCl3, and high-throughput mRNA-seq was performed to investigate the changes in the transcriptome after exposure to 4 mM AlCl3. Our findings indicate that exposure to AlCl3 led to an increase in oxidative stress, disrupted glutathione metabolism, reduced cell viability, and altered gene expression in mouse spermatocytes. Gene enrichment analysis revealed that the differentially expressed genes (DEGs) were associated with various biological functions such as mitochondrial inner membrane, response to oxidative stress. Furthermore, these DEGs were found to be enriched in pathways including proteasome, glutathione metabolism, oxidative phosphorylation, and Hif-1 signaling pathway. Real-time PCR and western blot were employed to validate the expression alterations of pivotal genes, and the outcomes exhibited concordance with the mRNA-seq findings. This study provides a theoretical basis for revealing the potential mechanism of male reproductive toxicity caused by aluminum exposure.

Filamin A facilitates NLRP3 inflammasome activation during arsenic-induced nonalcoholic steatohepatitis

Prolonged exposure to arsenic can cause nonalcoholic steatohepatitis (NASH). The NOD-like receptor protein 3 (NLRP3) inflammasome plays an essential role in the process of NASH. However, the mechanism by which arsenic promotes NLRP3 expression remains unclear. Three-month NaAsO2 gavage led to the nuclear factor-κB (NF-κB) signaling pathway activation and NASH. Additionally, NaAsO2 upregulated the level of Filamin A (FLNA) and pyroptosis, thereby activating the NLRP3 inflammasome in SD rat liver. Using FLNA siRNA, NASH-associated inflammation and pyroptosis were clearly mitigated by reducing activation of the NLRP3 inflammasome. Furthermore, arsenic treatment facilitated activation of the NF-κB signaling pathway and promoted p-p65 translocation into the nucleus. Chromatin immunoprecipitation (Ch-IP) assay indicated that FLNA promoted p65 binding to the NLRP3 gene and upregulated the transcription of NLRP3, ultimately leading to pyroptosis and NASH. Our findings indicate that FLNA and pyroptosis are strongly associated with NASH induced by NaAsO2. Collectively, the findings of this study indicated that FLNA mediates NF-κB signaling pathway-induced activation of the NLRP3 inflammasome and ultimately activates pyroptosis and NASH upon NaAsO2 exposure. This information may be useful for improving therapeutic strategies against arsenic-induced NASH.

Identification of biomarkers for risk assessment of arsenicosis based on untargeted metabolomics and machine learning algorithms

BACKGROUND

Long-term exposure to inorganic arsenic may lead to arsenicosis. There are, however, currently no validated metabolic biomarkers used for the identification of arsenicosis risk. This study aims to identify metabolites associated with arsenicosis and establish prediction models for risk assessment based on untargeted metabolomics and machine learning algorithms.

METHODS

In total, 105 coal-borne arsenicosis patients, with 35 subjects in each of the mild, moderate, and severe subgroups according to their symptom severity, and 60 healthy residents were enrolled from Guizhou, China. Ultra-high performance liquid chromatography-tandem mass spectrometer (UHPLC-MS/MS) was utilized to acquire the plasma metabolic profiles of the studied subjects. Statistical analysis was used to identify disease-associated metabolites. Machine learning algorithms and the identified metabolic biomarkers were resorted to assess the arsenicosis risk.

RESULTS

A total of 143 metabolic biomarkers, with organic acids being the majority, were identified to be closely associated with arsenicosis, and the most involved pathway was glycine, serine, and threonine metabolism. Comparative analysis of metabolites in arsenicosis patients with different symptom severity revealed 422 altered molecules, where disrupted metabolism of beta-alanine and arginine demonstrated the most significance. For risk assessment, the model established by a single biomarker (L-carnosine) could undoubtedly discriminate arsenicosis patients from the healthy. For classifying arsenicosis patients with different severity, the model established using 52 metabolites and linear discriminate analysis (LDA) algorithm yielded an accuracy of 0.970-0.979 on calibration set (n = 132) and 0.818-0.848 on validation set (n = 33).

CONCLUSION

Altered metabolites and disrupted pathways are prevalent in arsenicosis patients; The disrupted metabolism of one carbon and dysfunction of antioxidant defense system may partially be causes of the systematic multi-organ damage and carcinogenesis in arsenicosis patients; Metabolic biomarkers, combined with machine learning algorithms, could be efficient for risk assessment and early identification of arsenicosis.

The interplay of arsenic, silymarin, and NF-ĸB pathway in male reproductive toxicity: A review

Arsenic toxicity is one of the most trending reasons for several malfunctions, particularly reproductive toxicity. The exact mechanism of arsenic poisoning is a big question mark. Exposure to arsenic reduces sperm count, impairs fertilization, and causes inflammation and genotoxicity through interfering with autophagy, epigenetics, ROS generation, downregulation of essential protein expression, metabolite changes, and hampering several signaling cascades, particularly by the alteration of NF-ĸB pathway. This work tries to give a clear idea about the different aspects of arsenic resulting in male reproductive complications, often leading to infertility. The first part of this article explains the implications of arsenic poisoning and the crosstalk of the NF-ĸB pathway in male reproductive toxicity. Silymarin is a bioactive compound that exerts anti-cancer and anti-inflammatory properties and has demonstrated hopeful outcomes in several cancers, including colon cancer, breast cancer, and skin cancer, by downregulating the hyperactive NF-ĸB pathway. The next half of this article thus sheds light on silymarin's therapeutic potential in inhibiting the NF-ĸB signaling cascade, thus offering protection against arsenic-induced male reproductive toxicity.

SIRT1/PGC-1α is involved in arsenic-induced male reproductive damage through mitochondrial dysfunction, which is blocked by the antioxidative effect of zinc

Exposure to arsenic poses threats to male reproductive system, including impairing the testes and sperm quality. Although an association regarding arsenic exposure and male reproductive damage has been reported, the undergoing molecular mechanisms and interventions for prevention remain unclear. For the present work, male mice were exposed to 0, 2.5, 5, or 10 ppm sodium arsenite (NaAsO₂) for 8 months. The results showed that arsenic-exposed mice had reduced fertility with abnormalities in the testes, epididymides, and sperm. Exposure of mice to arsenic caused a redox imbalance, decreased SIRT1 and PGC-1α levels, and affected mitochondrial biogenesis and proteins related to mitochondrial dynamics. For immortalized spermatogenic (GC-2) cells, arsenic caused apoptosis and oxidative stress, reduced SIRT1/PGC-1α levels and ATP production, inhibited mitochondrial respiration, and changed the mitochondrial membrane potential (MMP). Mitochondrial biogenesis and dynamics were also impaired. However, by reducing mitochondrial damage in GC-2 cells, upregulation of SIRT1 or zinc (Zn) supplementation reversed the apoptosis induced by arsenic. For mice, Zn supplementation blocked arsenic-induced oxidative stress, the decreases of SIRT1 and PGC-1α levels, and the impairment of mitochondrial function, and it reversed the damage to testes, low sperm quality, and low litter size. Collectively, these results suggest that arsenic causes excessive production of ROS, inhibits the SIRT1/PGC-1α pathway, and causing mitochondrial dysfunction by mediating impairment of mitochondrial biogenesis and dynamics, which results in germ cells apoptosis and male reproductive damage, processes that are blocked by Zn via an antioxidative effect. Our study contributes to understanding of the mechanisms for arsenic-induced male reproductive damage and points to the therapeutic significance of Zn.

Thiram-induced hyperglycemia causes tibial dyschondroplasia by triggering aberrant ECM remodeling via the gut-pancreas axis in broiler chickens

Pesticide thiram is widely used in agriculture and has been demonstrated to cause tibial dyschondroplasia (TD) in birds. However, the underlying mechanism remains unclear. This work used multi-omics analysis to evaluate the molecular pathways of TD in broilers that were exposed to low level of thiram. Integrative analysis of transcriptomic, proteomic, and metabolomic revealed thiram activity in enhancing pathological ECM remodeling via attenuating the glycolysis pathway and activating the hexosamine and glucuronic acid pathways. Intriguingly, we found hyperglycemia as a crucial factor for ECM overproduction, which resulted in the development of TD. We further demonstrated that high glucose levels are caused by islet secretion dysfunction in thiram-treated broilers. A combination of factors, including lipid disorder, low-grade inflammation, and gut flora disturbance, might contribute to the dysregulation of insulin secretion. The current work revealed the underlying toxicological mechanisms of thiram-induced tibial dyschondroplasia through blood glucose disorder via the gut-pancreas axis in chickens for the first time, which makes it easier to figure out the health risks of pesticides for worldwide policy decisions.

Multi-omics analysis reveals that iron deficiency impairs spermatogenesis by gut-hormone synthesis axis

Considering that research has mainly focussed on how excessive iron supplementation leads to reproductive cytotoxicity, there is a lack of in-depth research on reproductive system disorders caused by iron deficiency. To gain a better understanding of the effects of iron deficiency on the reproductive system, especially spermatogenesis, we first constructed a mouse model of iron deficiency. We employed multi-omic analysis, including transcriptomics, metabolomics, and microbiomics, to comprehensively dissect the impact of iron deficiency on spermatogenesis. Moreover, we verified our findings in detail using western blot, immunofluorescence, immunohistochemistry, qRT-PCR and other techniques. Microbiomic analysis revealed altered gut microbiota in iron-deficient mice, and functional predictive analysis showed that gut microbiota can regulate spermatogenesis. The transcriptomic data indicated that iron deficiency directly alters expression of meiosis-related genes. Transcriptome data also revealed that iron deficiency indirectly regulates spermatogenesis by affecting hormone synthesis, findings confirmed by metabolomic data, western blot and immunofluorescence. Interestingly, competing endogenous RNA networks also play a vital role in regulating spermatogenesis after iron deficiency. Taken together, the data elucidate that iron deficiency impairs spermatogenesis and increases the risk of male infertility by affecting hormone synthesis and promoting gut microbiota imbalance.

As3MT-mediated SAM consumption, which inhibits the methylation of histones and LINE1, is involved in arsenic-induced male reproductive damage

Studies have demonstrated that arsenic (As) induces male reproductive injury, however, the mechanism remains unknown. The high levels of arsenic (3) methyltransferase (As3MT) promote As-induced male reproductive toxicity. For As-exposed mice, the germ cells in seminiferous tubules and sperm quality were reduced. Exposure to As caused lower S-adenosylmethionine (SAM) and 5-methylcytosine (5 mC) levels, histone and DNA hypomethylation, upregulation of long interspersed element class 1 (LINE1, or L1), defective repair of double-strand breaks (DSBs), and the arrest of meiosis, resulting in apoptosis of germ cells and lower litter size. For GC-2spd (GC-2) cells, As induced apoptosis, which was prevented by adding SAM or by reducing the expression of As3MT. The levels of LINE1, affected by SAM content, were involved in As-induced apoptosis. Furthermore, folic acid (FA) and vitamin B12 (VB₁₂) supplements restored SAM, 5 mC, and LINE1 levels and blocked impairment of spermatogenesis and testes and lower litter size. Exposed to As, mice with As3MT knockdown showed less impairment of spermatogenesis and testes and greater litter size compared to As-exposed wild-type (WT) mice. Thus, the high As3MT levels induced by As consume SAM and block histone and LINE1 DNA methylation, elevating LINE1 expression and evoking impairment of spermatogenesis, which causes male reproductive damage. Overall, we have found a mechanism for As-induced male reproductive damage, which provides biological insights into the alleviation of reproductive injury induced by environmental factors.

SOX2 modulated astrocytic process plasticity is involved in arsenic-induced metabolic disorders

Metabolic disorders induced by arsenic exposure have attracted great public concern. However, it remains unclear whether hypothalamus-based central regulation mechanisms are involved in this process. Here, we exposed mice to 100 μg/L arsenic in drinking water and established a chronic arsenic exposure model. Our study revealed that chronic arsenic exposure caused metabolic disorders in mice including impaired glucose metabolism and decreased energy expenditure. Arsenic exposure also impaired glucose sensing and the activation of proopiomelanocortin (POMC) neurons in the hypothalamus. In particular, arsenic exposure damaged the plasticity of hypothalamic astrocytic process. Further research revealed that arsenic exposure inhibited the expression of sex-determining region Y-Box 2 (SOX2), which decreased the expression level of insulin receptors (INSRs) and the phosphorylation of AKT. The conditional deletion of astrocytic SOX2 exacerbated arsenic-induced effects on metabolic disorders, the impairment of hypothalamic astrocytic processes, and the inhibition of INSR/AKT signaling. Furthermore, the arsenic-induced impairment of astrocytic processes and inhibitory effects on INSR/AKT signaling were reversed by SOX2 overexpression in primary hypothalamic astrocytes. Together, we demonstrated here that chronic arsenic exposure caused metabolic disorders by impairing SOX2-modulated hypothalamic astrocytic process plasticity in mice. Our study provides evidence of novel central regulatory mechanisms underlying arsenic-induced metabolic disorders and emphasizes the crucial role of SOX2 in regulating the process plasticity of adult astrocytes.

Toxicological effects of tris(1,3-dichloro-2-propyl) phosphate in oyster Crassostrea gigas using proteomic and phosphoproteomic analyses

As a typical organophosphorus pollutant, tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) has been widely detected in aquatic environment. Previous studies showed that protein phosphorylation might be a vital way of TDCIPP to exert multiple toxic effects. However, there is a lack of high-throughput investigations on how TDCIPP affected protein phosphorylation. In this study, the toxicological effects of TDCIPP were explored by proteomic and phosphoproteomic analyses together with traditional means in oysters Crassostrea gigas treated with 0.5, 5 and 50 μg/L TDCIPP for 28 days. Integration of omic analyses revealed that TDCIPP dysregulated transcription, energy metabolism, and apoptosis and cell proliferation by either directly phosphorylating pivotal proteins or phosphorylating their upstream signaling pathways. The U-shaped response of acetylcholinesterase activities suggested the neurotoxicity of TDCIPP in a hormesis manner. What's more, the increase in caspase-9 activity as well as the expression or phosphorylation alterations in eukaryotic translation initiation factor 4E, cell division control protein 42 and transforming growth factor-β1-induced protein indicated the disruption of homeostasis between apoptosis and cell proliferation, which was consistent with the observation of shedding of digestive cells. Overall, combination of proteomic and phosphoproteomic analyses showed the capability of identifying molecular events, which provided new insights into the toxicological mechanisms of TDCIPP.