Tributyltin chloride induces chondrocyte damage through the activation of NLRP3­mediated inflammation and pyroptosis.

Tributyltin chloride (TBTC) is known to have effects and mechanisms in various diseases; however, whether TBTC is detrimental to joints and causes osteoarthritis (OA), as well as its underlying mechanism, has not yet been fully elucidated. The present study explored the effects of TBTC on rat chondrocytes, as well as on mouse OA. The toxicity of TBTC toward rat chondrocytes was detected using a lactate dehydrogenase (LDH) leakage assay and cell viability was evaluated using the Cell Counting Kit­8 assay. The results showed that TBTC decreased the viability of rat chondrocytes and increased the LDH leakage rate in a concentration­dependent manner. Moreover, compared with in the control group, TBTC increased the expression levels of interleukin (IL)­1ß, IL­18, matrix metalloproteinase (MMP)­1, MMP­13, NLR family pyrin domain containing 3 (NLRP3), caspase­1, PYD and CARD domain containing, and gasdermin D in chondrocytes. Furthermore, knockdown of NLRP3 reversed the TBTC­induced increases in LDH leakage and NLRP3 inflammasome­associated protein levels. In vivo, TBTC exacerbated cartilage tissue damage in mice from the OA group, as evidenced by the attenuation of safranin O staining. In conclusion, TBTC may aggravate OA in mice by promoting chondrocyte damage and inducing pyroptosis through the activation of NLRP3 and caspase­1 signaling. The present study demonstrated that TBTC can cause significant damage to the articular cartilage; therefore, TBTC contamination should be strictly monitored.

Microcosm study reveals the microbial and environmental effects on tributyltin degradation in an estuarine sediment.

Tributyltin (TBT) is one of the most harmful contaminants ever released into the aquatic environment. Despite being banned, it is still present at many locations throughout the world. Its degradation in sediment mainly occurs through microbial biodegradation, a process that remains unclear. This study therefore aimed at better understanding TBT biodegradation in estuarine sediment and the microbial community associated with it. Microcosm experiments were set up, embracing a range of environmental control parameters. Major community shifts were recorded, mainly attributed to the change in oxygen status. The highest percentage of degradation (36,8%) occurred at 4 °C in anaerobic conditions. These results are encouraging for the in-situ bioremediation of TBT contaminated muddy sediment in temperate ports worldwide. However, with TBT able to persist in the coastal environment for decades when undisturbed in anoxic sediment, further research is needed to fully understand the mechanisms that triggered this biodegradation observed in the microcosms.

Maternal exposure to tributyltin alters the breast milk, hormonal profile, and thyroid morphology of dams and induces sex-specific changes in neonate rat offspring.

Tributyltin (TBT) is the chemical substance commonly used worldwide to prevent biofouling of vessels. Due to its ability to bioaccumulate and biomagnify, even after being banned, significant concentrations of TBT can be detected in sediment, affecting marine and human life. Although studies have shown that direct exposure to TBT alters physiological parameters in mammals, the relationship between exposure to TBT during pregnancy and lactation, considered critical windows for metabolic programming, has not been fully elucidated. Our hypothesis is that offspring whose mothers were exposed to TBT during critical stages of development may exhibit dysfunctions in endocrine-metabolic parameters. We used pregnant Wistar rats that were divided into groups and received the following treatments from gestational day 7 until the end of lactation by intragastric gavage: vehicle (ethanol 0.01%; Control), low TBT dose (100 ng/kg of body weight (bw)/day; TBT100ng) and high TBT dose (1000 ng/kg bw/day; TBT1000ng). Dams and offspring at birth and weaning (21 days old) were studied. Maternal exposure to TBT promoted dose-dependent changes in dams. The findings for adiposity, milk composition and lipid profile were more pronounced in TBT100 ng dam; however, thyroid morphology was altered in TBT1000 ng dam. Female offspring were differentially affected by the dose of exposure. At birth, females in the TBT100ng group had low body weight, lower naso-anal length (NAL), and higher plasma T4, and at weaning, females in the TBT100ng group had lower insulin and leptin levels. Females in the TBT1000ng group had lower NAL at birth and lower leptinemia and weight of white adipose tissue at weaning. Male offspring from TBT groups showed high T3 at birth, without biometric alterations at birth or weaning. Despite these findings, both sexes exhibited dose-dependent morphological changes in the thyroid gland. Thus, maternal exposure to TBT constitutes an important route of contamination for both dams and offspring.

Evaluation of Lipids and Lipid-Related Transcripts in Human and Ovine Theca Cells and an in Vitro Mouse Model Exposed to the Obesogen Chemical Tributyltin.

BACKGROUND: Exposure to obesogenic chemicals has been reported to result in enhanced adipogenesis, higher adipose tissue accumulation, and reduced ovarian hormonal synthesis and follicular function. We have reported that organotins [tributyltin (TBT) and triphenyltin (TPT)] dysregulate cholesterol trafficking in ovarian theca cells, but, whether organotins also exert lipogenic effects on ovarian cells remains unexplored. OBJECTIVE: We investigated if environmentally relevant exposures to organotins [TBT, TPT, or dibutyltin (DBT)] induce lipid dysregulation in ovarian theca cells and the role of the liver X receptor (LXR) in this effect. We also tested the effect of TBT on oocyte maturation and neutral lipid accumulation, and lipid-related transcript expression in cumulus cells and preimplantation embryos. METHODS: Primary theca cell cultures derived from human and ovine ovaries were exposed to TBT, TPT, or DBT (1, 10, or 50 ng/ml). The effect of these chemical exposures on neutral lipid accumulation, lipid abundance and composition, lipid homeostasis-related gene expression, and cytokine secretion was evaluated using liquid chromatography-mass spectrometry (LC-MS), inhibitor-based methods, cytokine secretion, and lipid ontology analyses. We also exposed murine cumulus-oocyte complexes to TBT and evaluated oocyte maturation, embryo development, and lipid homeostasis-related mRNA expression in cumulus cells and blastocysts. RESULTS: Exposure to TBT resulted in higher intracellular neutral lipids in human and ovine primary theca cells. In ovine theca cells, this effect was dose-dependent, independent of cell stage, and partially mediated by LXR. DBT and TPT resulted in higher intracellular neutral lipids but to a lesser extent in comparison with TBT. More than 140 lipids and 9 cytokines were dysregulated in TBT-exposed human theca cells. Expression of genes involved in lipogenesis and fatty acid synthesis were higher in theca cells, as well as in cumulus cells and blastocysts exposed to TBT. However, TBT did not impact the rates of oocyte maturation or blastocyst development. DISCUSSION: TBT induced dyslipidemia in primary human and ovine theca cells, which may be responsible for some of the TBT-induced fertility dysregulations reported in rodent models of TBT exposure. https://doi.org/10.1289/EHP13955.

Update on the status of the contamination by organotin compounds in sediment of Nuevo Gulf, Argentina. Insights from field and experimental studies.

Organotin compounds are persistent pollutants and are considered chemicals of high environmental concern. In the present study, the distribution and degradation of tributyltin were evaluated in field sediments and through an ex situ experiment. For this, sediment samples from two locations were analysed: Luis Piedrabuena Harbour, with higher maritime traffic, and Cerro Avanzado, which receives less impact from anthropogenic activities. The results indicated that pollution levels at Luis Piedrabuena Harbour have decreased compared with studies performed 9 years ago for the same area. On the contrary, traces of organotin compounds have been found for the first time at Cerro Avanzado. Moreover, the butyltin degradation index indicated that organotin compounds undergo an advanced degradation process in the collected samples at both sites. Ex situ experiments revealed a limited capacity of sediments to retain tributyltin, and suggested an active role of bioturbation activity in the degradation of these compounds. In addition, visualisation using chemometric techniques (principal components analysis) allowed a simpler analysis of two sediment characteristics: the degree of contamination and the degradation levels of organotin compounds.

Whole-Transcriptome Analysis Reveals the RNA Profiles in Mouse Bone Marrow Mesenchymal Stem Cells or Zebrafish Embryos After Exposure to Environmental Level of Tributyltin.

To understand the underlying molecular mechanisms, mouse bone marrow mesenchymal stem cells (BMSCs) and zebrafish embryos were exposed to the control group and Tributyltin (TBT) group (10 ng/L, environmental concentration) for 48 h, respectively. The expression profiles of RNAs were investigated using whole-transcriptome analysis in mouse BMSCs or zebrafish embryos after TBT exposure. For mouse BMSCs, the results showed 2,449 differentially expressed (DE) mRNAs, 59 DE miRNAs, 317 DE lncRNAs, and 15 circRNAs. Similarly, for zebrafish embryos, the results showed 1,511 DE mRNAs, 4 DE miRNAs, 272 DE lncRNAs, and 28 circRNAs. According to KEGG pathway analysis showed that DE RNAs were mainly associated with immune responses, signaling, and cellular interactions. Competing endogenous RNA (ceRNA) network analysis revealed that the regulatory network of miRNA-circRNA constructed in zebrafish embryos was more complex compared to that of mouse BMSCs.

Assessment of toxicity, genotoxicity and oxidative stress in Fejervarya limnocharis exposed to tributyltin.

Tributyltin (TBT) is widely used in various commercial applications due to its biocidal properties. Toxicological and genotoxicological data on TBT exposure to amphibians is insufficient. Our study aimed to determine the acute toxicity and genotoxic potential of TBT in Fejervarya limnocharis tadpoles. Furthermore, oxidative stress was also investigated in TBT-treated tadpoles. Tadpoles of Gosner stage (26-30) were screened and subjected to increasing concentrations of TBT (0, 3, 7, 11, 15, 19, 23 µg/L) for determining the LC50 values for 24 h, 48 h, 72 h, and 96 h. LC50 values of TBT for 24 h, 48 h, 72 h, and 96 h were found to be 19.45, 15.07, 13.12, and 11.84 µg/L respectively. Based on the 96 h LC50 value (11.84 µg/L), tadpoles were exposed to different sub-lethal concentrations of TBT for the evaluation of its genotoxic potential and effects on oxidative balance. The role of TBT on survivability, growth, and time to metamorphosis was also assessed. TBT exposure significantly altered the life history traits measured, increased mortality, and delayed the time taken to metamorphosis. Results indicated significant induction of micronucleus (MN, p < 0.001) and other erythrocytic nuclear aberrations (ENA, p < 0.01) in the TBT-treated groups. Significant alterations in comet parameters and oxidative balance were also observed in the treated groups. The present study findings might add to the cause of the gradual population decline seen in the amphibians. This study also demonstrates the alteration of the life-history traits, oxidative balance, and DNA damage upon TBT exposure which can have long-term consequences for the anuran amphibian F. limnocharis.

Developmental defects in cognition, metabolic and cardiac function following maternal exposures to low environmental levels of selective serotonin re-uptake inhibitors and tributyltin in Daphnia magna.

Aquatic organisms are exposed to low concentrations of neuro-active chemicals, many of them acting also as neuroendocrine disruptors that can be hazardous during earlier embryonic stages. The present study aims to assess how exposure early in live to environmental low concentrations of two selective serotonin reuptake inhibitors (SSRIs), fluoxetine and sertraline, and tributyltin (TBT) affected cognitive, metabolic and cardiac responses in the model aquatic crustacean Daphnia magna. To that end, newly brooded females were exposed for an entire reproductive cycle (3-4 days) and the response of collected juveniles in the first, second and third consecutive broods, which were exposed, respectively, as embryos, provisioned and un-provisioned egg stages, was monitored. Pre-exposure to the selected SSRIs during embryonic and egg developmental stages altered the swimming behaviour of D. magna juveniles to light in a similar way reported elsewhere by serotonergic compounds while TBT altered cognition disrupting multiple neurological signalling routes. The studied compounds also altered body size, the amount of storage lipids in lipid droplets, heart rate, oxygen consumption rates and the transcription of related serotonergic, dopaminergic and lipid metabolic genes in new-born individuals, mostly pre-exposed during their embryonic and provisioning egg stages. The obtained cognitive, cardiac and metabolic defects in juveniles developed from exposed sensitive pre-natal stages align with the "Developmental Origins of Health and Disease (DoHAD)" paradigm.

Factors affecting the accumulation of organotins by wild fish: A case study in the Three Gorges Reservoir, China.

Organotin compounds (OTs) accumulate in fish easily, however, research on their influencing factors is still limited. This study collected 25 species of fish with different diets, habitats, and age from the Three Gorges Reservoir (TGR), the largest deep-water river channel-type reservoir in China, and analyzed the accumulation characteristics of OTs in these fish. The results showed that tributyltin (TBT) and triphenyltin (TPhT) were the dominant OTs in fish from the TGR. The correlation between OTs concentration and age, body length, and body weight varied with fish species. The concentrations of TBT and TPhT in carnivorous fish (mean, 25.78 and 11.69 ng Sn/g dw, respectively) were higher than those in other diet fish (P<0.01), but there was no significant difference in fish at different habitat water layers (P>0.05). In addition, the degradation rates of TBT and TPhT in different fish species were all below 50%. In summary, the accumulation of TBT and TPhT in fish is mainly influenced by diet, and both TBT and TPhT were difficult to degrade in fish. These results reveal the pollution characteristics of OTs in fish from the TGR, and can improve our understanding of the factors influencing TBT and TPhT accumulation in freshwater fish.

Transgenerational Effects and Mechanisms of Tributyltin Exposure on Neurodevelopment in the Male Offspring of Rats.

This study aimed to investigate the transgenerational effects of tributyltin exposure on rat neurodevelopment in male offspring and the potential mechanisms. Neonatal female rats were exposed to the environmental level of tributyltin and then mated with nonexposed males after sexual maturity to produce the F1 generation. The F1 generation (with primordial germ cell exposure) was mated with nonexposed males to produce nonexposed offspring (the F2 and F3 generations). Neurodevelopmental indicators and behavior were observed for the F1, F2, and F3 generations during postnatal days 1-25 and 35-56, respectively. We found premature eye-opening and delayed visual positioning in newborn F1 rats and anxiety and cognitive deficits in prepubertal F1 male rats. These neurodevelopmental impacts were also observed in F2 and F3 males. Additionally, F1-F3 males exhibited increased serotonin and dopamine levels and a loose arrangement of neurons in the hippocampus. We also observed a reduction in the expression of genes involved in intercellular adhesion and increased DNA methylation of the Dsc3 promoter in F1-F3 males. We concluded that tributyltin exposure led to transgenerational effects on neurodevelopment via epigenetic reprogramming in male offspring. These findings provide insights into the risks of neurodevelopmental disorders in offspring from parents exposed to tributyltin.

Lipid accumulation and gene expression changes induced by tributyltin exposure in primary hepatocytes of lined seahorse (Hippocampus erectus).

Tributyltin (TBT), an antifouling biocide frequently detected in aquatic systems, is generally considered to be an environmental obesogen. However, alterations in lipid metabolism in aquatic animals that are exposed to TBT are scarcely known. This study examined the effects of in vitro exposure to TBT on hepatic lipid homeostasis in the lined seahorse (Hippocampus erectus). Primary seahorse hepatocyte cultures were established for the first time. TBT exposure (100 and 500 nM for 24 h) significantly promoted lipid accumulation in seahorse hepatocytes and drastically reduced the number of active intracellular lysosomes. Furthermore, exposure to TBT significantly upregulated the gene expression of lipogenic enzymes and transcription factors but downregulated that of genes involved in the catabolism of lipid droplets in seahorse hepatocytes. These results indicate that TBT disrupts hepatic lipid homeostasis by simultaneously promoting lipid synthesis and inhibiting lipid droplet breakdown in seahorses. The present study extends our understanding of the utilization of primary hepatocytes from marine animals for toxicological research, and the molecular evidence of the effects of TBT on hepatic lipid homeostasis in teleost fishes.

Biological Evaluation of Triorganotin Derivatives as Potential Anticancer Agents.

Metal-derived platinum complexes are widely used to treat solid tumors. However, systemic toxicity and tumor resistance to these drugs encourage further research into similarly effective compounds. Among others, organotin compounds have been shown to inhibit cell growth and induce cell death and autophagy. Nevertheless, the impact of the ligand structure and mechanisms involved in the toxicity of organotin compounds have not been clarified. In the present study, the biological activities of commercially available bis(tributyltin) oxide and tributyltin chloride, in comparison to those of specially synthesized tributyltin trifluoroacetate (TBT-OCOCF3) and of cisplatin, were assessed using cells with different levels of tumorigenicity. The results show that tributyltins were more cytotoxic than cisplatin in all the tested cell lines. NMR revealed that this was not related to the interaction with DNA but to the inhibition of glucose uptake into the cells. Moreover, highly tumorigenic cells were less susceptible than nontumorigenic cells to the nonunique pattern of death induced by TBT-OCOCF3. Nevertheless, tumorigenic cells became sensitive when cotreated with wortmannin and TBT-OCOCF3, although no concomitant induction of autophagy by the compound was detected. Thus, TBT-OCOCF3 might be the prototype of a family of potential anticancer agents.

Organotin mixtures reveal interactions that modulate adipogenic differentiation in 3T3-L1 preadipocytes.

Organotin chemicals (butyltins and phenyltins) are the most widely used organometallic chemicals worldwide and are used in industrial applications, such as biocides and anti-fouling paints. Tributyltin (TBT) and more recently, dibutyltin (DBT) and triphenyltin (TPT) have been reported to stimulate adipogenic differentiation. Although these chemicals co-exist in the environment, their effect in combination remains unknown. We first investigated the adipogenic effect of eight organotin chemicals (monobutyltin (MBT), DBT, TBT, tetrabutyltin (TeBT), monophenyltin (MPT), diphenyltin (DPT), TPT, and tin chloride (SnCl4)) in the 3T3-L1 preadipocyte cell line in single exposures at two doses (10 and 50 ng/ml). Only three out of the eight organotins induced adipogenic differentiation with TBT eliciting the strongest adipogenic differentiation (in a dose-dependent manner) followed by TPT and DBT, as demonstrated by lipid accumulation and gene expression. We then hypothesized that, in combination (TBT, DBT, and TPT), adipogenic effects will be exacerbated compared to single exposures. However, at the higher dose (50 ng/ml), TBT-induced differentiation was reduced by TPT and DBT when in dual or triple combination. We tested whether TPT or DBT would interfere with adipogenic differentiation stimulated by a peroxisome proliferator-activated receptor (PPARγ) agonist (rosiglitazone) or a glucocorticoid receptor agonist (dexamethasone). Both DBT50 and TPT50 reduced rosiglitazone-, but not dexamethasone-stimulated adipogenic differentiation. In conclusion, DBT and TPT interfere with TBT's adipogenic differentiation possibly via PPARγ signaling. These findings highlight the antagonistic effects among organotins and the need to understand the effects and mechanism of action of complex organotin mixtures on adipogenic outcomes.

The possible ameliorative role of Lycopene on Tributyltin induced thyroid damage in adult male albino rats (histological, immunohistochemical and biochemical study).

Tributyltin is used in industrial applications. This current research aimed to study the effect of Tributyltin on the thyroid gland structure and function of adult male albino rats and the protective effect of Lycopene. Twenty-one male adult albino rats were classified into three groups: Control, treated that received Tributyltin, and protective that received Lycopene with Tributyltin. At the end of the experiment, blood samples were collected and T4, T3, and (TSH) were measured. Tissue superoxide dismutase (SOD) and malondialdehyde (MDA) were estimated. Thyroid gland specimens were processed for histological and immunohistochemical examination. Then morphometric and statistical analyses were done. The treated group showed affection in thyroid function and histological structure as vacuolated colloid and cytoplasm and dark nuclei. Ultrastructurally, follicular cells showed irregular shrunken nuclei, atrophied apical microvilli, vacuoles, multiple lysosomal granules, mitochondria with destructed cristae, and extensively dilated rough endoplasmic reticulum. There was increase in Caspase-3 immunoexpression and decrease in Beclin-1 immunoexpression. The thyroid structure and biochemical markers improved after Lycopene administration. The thyroid gland damage caused by Tributyltin is ameliorated by Lycopene.

Embryonic exposure to environmentally relevant levels of tributyltin affects embryonic tributyltin bioaccumulation and the physiological responses of juveniles in cuttlefish (Sepia pharaonis).

Tributyltin (TBT) is a typical organic pollutant that persists in aquatic sediments due to its wide usage as an antifouling fungicide during the past few decades. Despite increased awareness of the serious negative consequences of TBT on aquatic species, studies on the effects of TBT exposure on cephalopod embryonic development and juvenile physiological performance are scarce. To investigate the lasting effects of TBT toxicity on Sepia pharaonis from embryo to hatchling, embryos (gastrula stage, 3-5 h post fertilization) were exposed to four levels of TBT until hatching: 0 (control), 30 (environmental level), 60, and 120 ng/L. Subsequently, juvenile growth performance endpoints and behavioral alterations were assessed over 15 days post-hatching. Egg hatchability was significantly reduced and embryonic development (i.e., premature hatching) was accelerated in response to 30 ng/L TBT exposure. Meanwhile, TBT-induced alterations in embryonic morphology primarily included yolk-sac lysis, embryonic malformations, and uneven pigment distributions. During the pre-middle stage of embryonic development, the eggshell serves as an effective barrier to safeguard the embryo from exposure to 30-60 ng/L TBT, according to patterns of TBT accumulation and distribution in the egg compartment. However, even environmental relevant levels of TBT (30 ng/L) exposure during embryonic development had a negative impact on juvenile behavior and growth, including slowing growth, shortening eating times, causing more irregular movements, and increasing inking times. These findings indicate that after TBT exposure, negative long-lasting effects on S. pharaonis development from embryo to hatchling persist, suggesting that long-lasting toxic effects endure from S. pharaonis embryos to hatchlings.

Tributyltin activates the Keap1-Nrf2 pathway via a macroautophagy-independent reduction in Keap1.

Tributyltin (TBT) is an environmental chemical, which was used as an antifouling agent for ships. Although its use has been banned, it is still persistently present in ocean sediments. Although TBT reportedly causes various toxicity in mammals, few studies on the mechanisms of biological response against TBT toxicity exist. The well-established Keap1-Nrf2 pathway is activated as a cytoprotective mechanism under stressful conditions. The relationship between TBT and the Keap1-Nrf2 pathway remains unclear. In the present study, we evaluated the effect of TBT on the Keap1-Nrf2 pathway. TBT reduced Keap1 protein expression in Neuro2a cells, a mouse neuroblastoma cell line, after 6 hr without altering mRNA expression levels. TBT also promoted the nuclear translocation of Nrf2, a transcription factor for antioxidant proteins, after 12 hr and augmented the expression of heme oxygenase 1, a downstream protein of Nrf2. Furthermore, TBT decreased Keap1 levels in mouse embryonic fibroblast (MEF) cells, with the knockout of Atg5, which is essential for macroautophagy, as well as in wild-type MEF cells. These results suggest that TBT activates the Keap1-Nrf2 pathway via the reduction in the Keap1 protein level in a macroautophagy-independent manner. The Keap1-Nrf2 pathway is activated by conformational changes in Keap1 induced by reactive oxygen species or electrophiles. Furthermore, any unutilized Keap1 protein is degraded by macroautophagy. Understanding the novel mechanism governing the macroautophagy-independent reduction in Keap1 by TBT may provide insights into the unresolved biological response mechanism against TBT toxicity and the activation mechanism of the Keap1-Nrf2 pathway.

Biochemical mechanisms of tributyltin chloride-induced cell toxicity in Sertoli cells.

Tributyltin chloride (TBTCL) is a widely used fungicide and heat stabilizer in compositions of PVC. TBTCL has been detected in human bodies and potentially causes harmful effects on humans' thyroid, cardiovascular and other organs. As one of the first examples of endocrine disruptors, the toxicity effects of TBTCL on the male reproduction system have aroused concerns. However, the potential cellular mechanisms are not fully explored. In the current study, by using Sertoli cells, a critical regulator of spermatogenesis as a cell model, we showed that with 200 nM exposure for 24 h, TBTCL causes apoptosis and cell cycle arrest. RNA sequencing analyses suggested that TBTCL probably activates endoplasmic reticulum (ER) stress, and disrupts autophagy. Biochemical analysis showed that TBTCL indeed induces ER stress and the dysregulation of autophagy. Interestingly, activation of ER stress and inhibition of autophagy is responsible for TBTCL-induced apoptosis and cell cycle arrest. Our results thus uncovered a novel insight into the cellular mechanisms for TBTCL-induced toxicology in Sertoli cells.

Toxicity of tributyltin to the European flat oyster Ostrea edulis: Metabolomic responses indicate impacts to energy metabolism, biochemical composition and reproductive maturation.

Tri-Butyl Tin (TBT) remains as a legacy pollutant in the benthic environments. Although the toxic impacts and endocrine disruption caused by TBT to gastropod molluscs have been established, the changes in energy reserves allocated to maintenance, growth, reproduction and survival of European oysters Ostrea edulis, a target species of concerted benthic habitat restoration projects, have not been explored. This study was designed to evaluate the effect of TBT chloride (TBTCl) on potential ions and relevant metabolomic pathways and its association with changes in physiological, biochemical and reproductive parameters in O. edulis exposed to environmental relevant concentrations of TBTCl. Oysters were exposed to TBTCl 20 ng/L (n = 30), 200 ng/L (n = 30) and 2000 ng/L (n = 30) for nine weeks. At the end of the exposure, gametogenic stage, sex, energy reserve content and metabolomic profiling analysis were conducted to elucidate the metabolic alterations that occur in individuals exposed to those compounds. Metabolite analysis showed significant changes in the digestive gland biochemistry in oysters exposed to TBTCl, decreasing tissue ATP concentrations through a combination of the disruption of the TCA cycle and other important molecular pathways involved in homeostasis, mitochondrial metabolism and antioxidant response. TBTCl exposure increased mortality and caused changes in the gametogenesis with cycle arrest in stages G0 and G1. Sex determination was affected by TBTCl exposure, increasing the proportion of oysters identified as males in O. edulis treated at 20ng/l TBTCl, and with an increased proportion of inactive stages in oysters treated with 2000 ng/l TBTCl. The presence and persistence of environmental pollutants, such as TBT, could represent an additional threat to the declining O. edulis populations and related taxa around the world, by increasing mortality, changing reproductive maturation, and disrupting metabolism. Our findings identify the need to consider additional factors (e.g. legacy pollution) when identifying coastal locations for shellfish restoration.

Co-expression analysis of lncRNA and mRNA identifies potential adipogenesis regulatory non-coding RNAs involved in the transgenerational effects of tributyltin.

The obesity epidemic is considered a global public health crisis, with an increase in caloric intake, sedentary lifestyles and/or genetic predispositions as contributing factors. Although the positive energy balance is one of the most significant causes of obesity, recent research has linked early exposure to Endocrine-Disrupting Chemicals (EDCs) such as the obesogen tributyltin (TBT) to the disease epidemic. In addition to their actions on the hormonal profile, EDCs can induce long-term changes in gene expression, possibly due to changes in epigenetic patterns. Long non-coding RNAs (lncRNAs) are epigenetic mediators that play important regulatory roles in several biological processes, through regulation of gene transcription and/or translation. In this study, we explored the differential expression of lncRNAs in gonadal white adipose tissue samples from adult male C57BL/6J F4 generation, female C57BL/6J offspring exposed (F0 generation) to 50 nM TBT or 0.1% DMSO (control of vehicle) via drinking water provided during pregnancy and lactation, analyzing RNA-seq data from a publicly available dataset (GSE105051). A total of 74 lncRNAs were differentially expressed (DE), 22 were up-regulated and 52 were down-regulated in the group whose F4 ancestor was exposed in utero to 50nM TBT when compared to those exposed to 0.1% DMSO (control). Regulation of DE lncRNAs and their potential partner genes in gonadal white adipose tissue of mice ancestrally exposed to EDC TBT may be related to the control of adipogenesis, as pathway enrichment analyses showed that these gene partners are mainly involved in the metabolism of lipids and glucose and in insulin-related pathways, which are essential for obesity onset and control.

Tributyltin degrading microbial enzymes: A promising remediation approach.

Brazil is one of the countries most impacted along the entire coastline by the presence of tributyltin (TBT), a biocide used in antifouling paints. Despite being banned since 2008, its use is still registered in the country, and it is possible to find recent inputs of this substance in places under the influence of shipyards, marinas, and fishing ports. In this study, a bacterium isolated from TBT-contaminated sediment from Santos and São Vicente Estuarine System (SESS) in Brazil, identified as Achromobacter sp., proved to be resistant to this compound. Furthermore, its crude enzymatic extract presented the ability to reduce up to 25 % of the initial TBT concentration in the liquid phase in 1 h, demonstrating to be a simple, fast, effective procedure and a potential tool for the environmental attenuation of TBT.