4-Nonylphenol triggers apoptosis and affects 17-β-Estradiol receptors in calvarial osteoblasts

Lycium barbarum polysaccharides attenuate nonylphenol and octylphenol-induced oxidative stress and neurotransmitter disorders in PC-12 cells

Nonylphenol (NP) and octylphenol (OP) are environmental contaminants with potential endocrine disrupting effects. However, there is limited research on the mechanisms and intervention of combined NP and OP exposure-induced neurotoxicity. This study aims to explore the cytotoxicity of combined NP and OP exposure and evaluate the potential of Lycium barbarum polysaccharides (LBP) in mitigating the aforementioned toxicity. In present study, LBP (62.5, 125 and 250 µg/mL) were applied to intervene rat adrenal pheochromocytoma (PC-12) cells treated with combined NP and OP (NP: OP = 4:1, w/w; 1, 2, 4 and 8 µg/mL). The results showed that NP and OP induced oxidative stress, disrupted the 5-hydroxytryptamine (5-HT) and cholinergic systems in PC-12 cells. Additionally, they activated the p38 protein kinase (p38) and suppressed the expression of silent information regulation type 1 (SIRT1), monoamine oxidase A (MAOA), phosphorylated cyclic-AMP response binding protein (p-CREB), brain-derived neurotrophic factor (BDNF) and phosphorylated tropomyosin-related kinase receptor type B (p-TrkB). However, N-acetyl-L-cysteine (NAC) treatment counteracted the changes of signalling molecule p38, SIRT1/MAOA and CREB/BDNF/TrkB pathways-related proteins induced by NP and OP. LBP pretreatment ameliorated combined NP and OP exposure-induced oxidative stress and neurotransmitter imbalances. Furthermore, the application of LBP and administration of a p38 inhibitor both reversed the alterations in the signaling molecule p38, as well as the proteins associated to the SIRT1/MAOA and CREB/BDNF/TrkB pathways. These results implied that LBP may have neuroprotective effects via p38-mediated SIRT1/MAOA and CREB/BDNF/TrkB pathways.

Endocrine disrupting chemicals in the environment: Environmental sources, biological effects, remediation techniques, and perspective

Endocrine disrupting chemicals (EDCs) have been identified as emerging contaminants, which poses a great threat to human health and ecosystem. Pesticides, polycyclic aromatic hydrocarbons, dioxins, brominated flame retardants, steroid hormones and alkylphenols are representative of this type of contaminant, which are closely related to daily life. Unfortunately, many wastewater treatment plants (WWTPs) do not treat EDCs as targets in the normal treatment process, resulting in EDCs entering the environment. Few studies have systematically reviewed the related content of EDCs in terms of occurrence, harm and remediation. For this reason, in this article, the sources and exposure routes of common EDCs are systematically described. The existence of EDCs in the environment is mainly related to human activities (Wastewater discharges and industrial activities). The common hazards of these EDCs are clarified based on available toxicological data. At the same time, the mechanism and effect of some mainstream EDCs remediation technologies (such as adsorption, advanced oxidation, membrane bioreactor, constructed wetland, etc.) are separately mentioned. Moreover, our perspectives are provided for further research of EDCs.

Involvement of the TNF-α/SATB2 axis in the induced apoptosis and inhibited autophagy of osteoblasts by the antipsychotic Risperidone

BACKGROUND

Risperidone, an atypical antipsychotic, impedes serotonin and dopamine receptor systems. Meanwhile, tumor necrosis factor-α (TNF-α) is known to participate in regulating osteoblast functions. Consequently, the current study aimed to investigate whether the influences of Risperidone on osteoblast functions are associated with TNF-α and special AT-rich sequence-binding protein (SATB2).

METHODS

Firstly, we searched the DGIdb, MEM and GeneCards databases to identify the critical factors involved in the effects of Risperidone on osteoblasts, as well as their interactions. Afterwards, osteoblast cell line MC3T3-E1 was transduced with lentivirus carrying si-TNF-α, si-SATB2 or both and subsequently treated with Risperidone. Various abilities including differentiation, autophagy and apoptosis of osteoblasts were examined after different treatments. Finally, animal experiments were performed with Risperidone alone or together with lentivirus to verify the function of Risperidone in vivo and the mechanism.

RESULTS

It was found that Risperidone might promote TNF-α expression, thereby inhibiting the expression of SATB2 to affect the autophagy and apoptosis in osteoblasts. Furthermore, as shown by our experimental findings, Risperidone treatment inhibited the differentiation and autophagy, and promoted the apoptosis of osteoblasts, as evidenced by elevated levels of OPG, p62, cleaved PARP1, cleaved caspase-3, cleaved caspase-8, and cleaved caspase-9, and reduced levels of LC3 II/I, Beclin1, collagen I, and RANKL. In addition, Risperidone was also found to elevate the expression of TNF-α to down-regulate SATB2, thereby inhibiting the differentiation and autophagy and enhancing the apoptosis of osteoblasts in vitro and in vivo.

CONCLUSIONS

Collectively, our findings indicated that Risperidone affects the differentiation of osteoblasts by inhibiting autophagy and enhancing apoptosis via TNF-α-mediated down-regulation of SATB2.

Endocrine disrupting chemicals and bone

Endocrine-disrupting chemicals (EDCs) are defined as chemicals that interfere with the function of the endocrine system. EDCs exert their hormonal effects through several mechanisms; modulating hormone receptors or changing metabolism of different hormones. EDCs also influence multiple signalling pathways while effecting the hormonal systems and possess complex dose-response curves. EDCs can exert deleterious effects on bone tissue through changing bone modelling and remodelling via altering bone paracrine hormone synthesis, the release of systemic hormones, cytokines, chemokines and growth factors, and effecting stem cell fate, as well as bone marrow mesenchymal stem cell differentiation. Evidence is accumulating of the bone disrupting effect of different groups of EDCs, such as; the perfluoroalkyl substances, the phthalate esters, the bisphenol A, the organotin compounds, the alkylphenols and the dioxin and dioxin-like compounds. This review highlights the recent discoveries of the effects of commonly found environmental chemicals on bone from basic molecular findings to clinical implications.

Endocrine Disruptors as a New Etiologic Factor of Bone Tissue Diseases (Review)

At present, diseases of bones and joints stand third after cardiovascular and oncological pathologies which demands the necessity of searching for new etiological factors and pathogenetical mechanisms of these illnesses. The accumulating data show the association between the impairment of bone tissue development and regeneration and endocrine disruptor impact. Endocrine disruptors are chemical substances, mainly of anthropogenic origin, capable of affecting endocrine system functioning and interfering with organ morphogenesis and physiological functions. The development and regeneration of bone tissues have a complex hormonal regulation and therefore bone tissue cells, osteoblasts, and osteoclasts can be considered as potential targets for endocrine disruptors. Endocrine disruptors have been established to be able to impair calcium metabolism which also contributes to the development of musculoskeletal system pathology. Data on histogenesis of bone tissue and regeneration, calcium metabolism as well as on hormonal regulation of bone growth and remodeling processes are presented in this work. Recent information on the effect of the main endocrine disruptor classes (diethylstilbestrol, organochlorine pesticides, alkylphenols, bisphenol A, dioxins, polychlorinated biphenyls, and phthalic acid esters) on the development and remodeling of bone tissues and calcium metabolism has been summarized. The established physiological and molecular mechanisms of their action have been also considered.

Molecular and cellular mechanisms linking air pollution and bone damage

Air pollution is the second most important risk factor associated with noncommunicable diseases after smoking. The effects of pollution on health are commonly attributable to particulate matter (PM), a complex mixture of particles suspended in the air. PM can penetrate the lower respiratory tract and has harmful direct and indirect effects on different organs and tissues. Direct effects are caused by the ability of PM components to cross the respiratory membrane and enter the bloodstream; indirect effects are systemic consequences of the local airway response. Recent work suggests that PM is an independent risk factor for low bone mineral density and osteoporosis-related fractures. Osteoporosis is a common age-related disease closely linked to bone fractures, with severe clinical consequences affecting quality of life, morbidity, and mortality. In this review, we discuss potential mechanisms behind the association between outdoor air pollution, especially PM, and bone damage. The discussion features four main mechanisms: 1) several different atmospheric pollutants can induce low-grade systemic inflammation, which affects bone metabolism through a specific effect of cytokines such as TNFα, IL-1β, IL-6, and IL-17 on osteoblast and osteoclast differentiation and function; 2) some pollutants, particularly certain gas and metal compounds, can cause oxidative damage in the airway and bone cells; 3) different groups of pollutants can act as endocrine disruptors when binding to the receptors in bone cells, changing their functioning; and 4) air pollution can directly and indirectly cause vitamin D deficiency. Characterizing these mechanisms will better define the physiopathology of bone damage, and recognizing air pollution as a modifiable risk factor for osteoporosis will inform environmental policies. Such knowledge will also guide the prevention of fractures due to fragility and help reduce health-related costs.

The environmental hormone nonylphenol interferes with the therapeutic effects of G protein-coupled estrogen receptor specific agonist G-1 on murine allergic rhinitis

The G protein-coupled estrogen receptor (GPER) specific agonist G-1 has therapeutic effects in patients with allergic diseases, but any role for G-1 as a therapy for inflammation associated with allergic rhinitis (AR) remains unclear. The structure of the environmental hormone nonylphenol (NP) is very similar to that of estrogen; it binds to the estrogen receptor to produce estrogen-like effects and thus may also bind to the membrane GPER. We explored whether NP administration would reduce the effects of G-1 on AR, the interactions between the two materials, and their mechanisms of action using a murine model of AR. Mice were randomly assigned into control, AR, G-1, and G-1 + NP groups (n = 10/group). AR nasal symptoms were scored. Eosinophils in nasal mucosa were counted after staining with hematoxylin and eosin. Serum ovalbumin (OVA)-specific IgE was determined by ELISA. The proportions of splenic Th1, Th2, and Treg cells were determined by flow cytometry. The expression of transcription factors unique to Th1, Th2, Treg cells and cytokine levels in nasal mucosa were evaluated by real-time PCR and cytometric bead arrays. AR nasal symptoms, including sneezing, nasal scratching, eosinophil infiltration of nasal mucosa, and serum IgE, were reduced in G-1 group. After injection, Th2 cells proportions, Th2-immune response-related cytokines (IL-4, IL-5, and IL-13), and a Th2 cell-specific transcription factor (GATA-3) were significantly decreased in G-1 group. Treg immune response was enhanced (as reflected by Treg cell, IL-10, and Foxp3 levels). The levels of all of these were significantly increased after adding NP, and the Treg immune response was significantly decreased. These results indicate that G-1 attenuated the nasal symptoms, serum OVA-specific IgE, and Th2 cell immune response, whereas it enhanced Treg immune response, in mice with AR. Adding NP weakened these therapeutic effects.

BPA disrupts the cardioprotection by 17β-oestradiol against ischemia/reperfusion injury in isolated guinea pig hearts

Bisphenol A (BPA) is an environmental oestrogen or xenoestrogen (XEs). XEs represent a health risk due to their potential for endocrine disruption and ability to mimic estrogenic activity. The effects of BPA on isolated hearts under normal and ischemia/reperfusion (I/R) conditions were investigated for the first time, with a focus on the effects of BPA and 17β-oestradiol (E₂) co-administration on I/R injury. Our results indicated that BPA at 10^-7 M and 10^-5 M did not significantly affect heart rate (HR), coronary flow (CF), lactate dehydrogenase (LDH) or creatine kinase (CK) release in normal or I/R isolated hearts within the 90 min. However, E₂ exerted a protective effect against I/R injury, whereas, BPA inhibited the cardio-protective effects of E₂ on HR, CF, and LDH and CK release. Furthermore, BPA in combination with E₂ aggravated I/R injury by increasing infarct size and causing a more severe ultrastructural disruption as compared to treatment with E₂ alone. Based on our results, we conclude that BPA inhibits the cardio-protective effects of E₂ on I/R-injured hearts, despite not significantly affecting normal or I/R isolated hearts.

Effects of separate or combined exposure of nonylphenol and octylphenol on central 5-HT system and related learning and memory in the rats

This study evaluated toxic effects of nonylphenol (NP) and octylphenol (OP) on central 5-hydroxytryptamine (5-HT) system and related learning and memory in the rats. Male Sprague-Dawley rats were exposed to NP (30, 90, or 270 mg/kg), OP (40, 120, or 360 mg/kg), or a mixture of NP and OP [(mixed with the corresponding NP, OP alone exposed low, medium and high dose according to the natural environment exists NP:OP = 4:1; NOL (24 mg/kg NP+8 mg/kg OP), NOM (72 mg/kg NP+24 mg/kg OP), NOH (216 mg/kg NP+72 mg/kg OP)] by gavage every other day for 30 d. Learning and memory were assessed using a passive-avoidance test. Levels of estrogen receptor β (ERβ), 5-HT, tryptophan hydroxylase 2 (TPH2), monoamine oxidase (MAOA) enzyme, serotonin transporter (SERT), the vesicular monoamine transporter 2 (VMAT2), 5-hydroxytryptamine 1 A (5-HT_1A), 5-hydroxytryptamine 3 A (5-HT_3A), 5-hydroxytryptamine 3B (5-HT_3B), 5-hydroxytryptamine 4 A (5-HT_4A) and 5-hydroxytryptamine 6 A (5-HT_6A) were measured using ELISA kits. Levels of ERβ, MAOA, SERT, VMAT2, 5-HT_1A, 5-HT_3A, 5-HT_3B, 5-HT_4A and 5-HT_6A in rat hippocampal reduced by a high dose of NP and/or OP. Levels of TPH2 in rat midbrain and 5-HT in rat hippocampal increased by a high dose of NP and/or OP. In addition, latency was significantly shorter and errors were significantly greater in the high dose NP and NP+OP (NO) groups. Taken together, these results suggest that NP and/or OP may affect learning and memory in rats by inhibiting levels of ERβ, which could then lead to decreases in levels of 5-HT_1A, 5-HT_3A, 5-HT_3B, 5-HT_4A, and 5-HT_6A in the rat hippocampus. These findings suggested that separate and combined exposure to NP and OP could produce toxic effects on central 5-HT system and related learning and memory in the rats.

4-Nonylphenol induces disruption of spermatogenesis associated with oxidative stress-related apoptosis by targeting p53-Bcl-2/Bax-Fas/FasL signaling

4-Nonylphenol (NP) is a ubiquitous environmental chemical with estrogenic activity. Our aim was to test the hypothesis that pubertal exposure to NP leads to testicular dysfunction. Herein, 24 7-week-old rats were randomly divided into four groups and treated with NP (0, 25, 50, or 100 mg/kg body weight every 2 days for 20 consecutive days) by intraperitoneal injection. Compared to untreated controls, the parameters of sperm activation rate, curvilinear velocity, average path velocity, and swimming velocity were significantly lower at doses of 100 mg/kg, while sperm morphological abnormalities were higher, indicating functional disruption and reduced fertilization potential. High exposure to NP (100 mg/kg) resulted in disordered arrangement of spermatoblasts and reduction of spermatocytes in seminiferous tubules, while tissues exhibited a marked decline in testicular fructose content and serum FSH, LH, and testosterone levels. Oxidative stress was induced by NP (50 or 100 mg/kg) as evidenced by elevated MDA, decreased SOD and GSH-Px, and inhibited antioxidant gene expression (CAT, GPx, SOD1, and CYP1B1). In addition, NP treatment decreased proportions of Ki-67-positive cells and increased apoptosis in a dose-dependent manner. Rats treated with 100 mg/kg NP exhibited significantly increased mRNA expression of caspase-1, -2, -9, and -11, decreased caspase-8 and PCNA1 mRNA expression, downregulation of Bcl-2/Bax ratios and upregulation of Fas, FasL, and p53 at the protein and mRNA levels. Taken together, NP-induced apoptosis, hormonal deficiencies, and depletion of fructose potentially impairs spermatogenesis and sperm function. p53-independent Fas/FasL-Bax/Bcl-2 pathways may be involved in NP-induced oxidative stress-related apoptosis. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 739-753, 2017.

The Effects of Endocrine Disruptors on Adipogenesis and Osteogenesis in Mesenchymal Stem Cells: A Review

Endocrine-disrupting chemicals (EDCs) are prevalent in the environment, and epidemiologic studies have suggested that human exposure is linked to chronic diseases, such as obesity and diabetes. In vitro experiments have further demonstrated that EDCs promote changes in mesenchymal stem cells (MSCs), leading to increases in adipogenic differentiation, decreases in osteogenic differentiation, activation of pro-inflammatory cytokines, increases in oxidative stress, and epigenetic changes. Studies have also shown alteration in trophic factor production, differentiation ability, and immunomodulatory capacity of MSCs, which have significant implications to the current studies exploring MSCs for tissue engineering and regenerative medicine applications and the treatment of inflammatory conditions. Thus, the consideration of the effects of EDCs on MSCs is vital when determining potential therapeutic uses of MSCs, as increased exposure to EDCs may cause MSCs to be less effective therapeutically. This review focuses on the adipogenic and osteogenic differentiation effects of EDCs as these are most relevant to the therapeutic uses of MSCs in tissue engineering, regenerative medicine, and inflammatory conditions. This review will highlight the effects of EDCs, including organophosphates, plasticizers, industrial surfactants, coolants, and lubricants, on MSC biology.

Environmental immune disruptors, inflammation and cancer risk

An emerging area in environmental toxicology is the role that chemicals and chemical mixtures have on the cells of the human immune system. This is an important area of research that has been most widely pursued in relation to autoimmune diseases and allergy/asthma as opposed to cancer causation. This is despite the well-recognized role that innate and adaptive immunity play as essential factors in tumorigenesis. Here, we review the role that the innate immune cells of inflammatory responses play in tumorigenesis. Focus is placed on the molecules and pathways that have been mechanistically linked with tumor-associated inflammation. Within the context of chemically induced disturbances in immune function as co-factors in carcinogenesis, the evidence linking environmental toxicant exposures with perturbation in the balance between pro- and anti-inflammatory responses is reviewed. Reported effects of bisphenol A, atrazine, phthalates and other common toxicants on molecular and cellular targets involved in tumor-associated inflammation (e.g. cyclooxygenase/prostaglandin E2, nuclear factor kappa B, nitric oxide synthesis, cytokines and chemokines) are presented as example chemically mediated target molecule perturbations relevant to cancer. Commentary on areas of additional research including the need for innovation and integration of systems biology approaches to the study of environmental exposures and cancer causation are presented.

Interferences of an environmental pollutant with estrogen-like action in the male reproductive system of the terrestrial vertebrate Podarcis sicula

Nonylphenol (NP) is classified among the endocrine disruptor chemicals with estrogen-like properties. It is widely used in many industries and to dilute pesticides in agriculture, and is known to affect the reproductive system of many aquatic and semi-aquatic organisms. This study aimed to verify how NP, administered via food and water, may interfere with the reproductive cycle of a terrestrial vertebrate. Our model was the male Italian wall lizard Podarcis sicula, a seasonal breeding species that may be naturally exposed to environmental pollution. From our findings it emerges that an NP-polluted diet administered during the mating period causes in this lizard a slowdown of spermatogenesis and affects the testicular and epididymal structure, making it similar to that of the non-reproductive period. The distribution in the testis and epididymis of mRNA for steroid hormone receptors, i.e., estrogen α and β and androgen receptors, was also investigated. NP treatment inhibits the expression of AR, ERα, and ERβ-mRNA in spermatogonia and primary spermatocytes and causes a switch-off of the secretory activity of the epididymal corpus by inducing the expression of ERα.

Apoptotic and neurotoxic actions of 4-para-nonylphenol are accompanied by activation of retinoid X receptor and impairment of classical estrogen receptor signaling

4-para-Nonylphenol (NP) is a non-ionic surfactant that has widespread and uncontrolled distribution in the environment. Little is known, however, about its actions on neuronal cells during critical developmental periods. This study aimed to investigate the mechanisms underlying the apoptotic and toxic actions of NP on mouse embryonic neuronal cells and the possible interactions of NP with estrogen receptor (ER)- and retinoid X receptor (RXR)-mediated intracellular signaling. Treatment of mouse hippocampal neuronal cell cultures with NP (5 and 10μM) induced apoptotic and neurotoxic effects. The 2 and 7 day-old mouse hippocampal cultures were vulnerable to 5 and 10μM NP, whereas 12 day-old cultures responded only to the highest concentration of NP, thus suggesting an age-dependent action of the chemical on neuronal cells. The use of specific inhibitors did not support the involvement of calpains in NP-induced apoptosis, but indicated caspase-8- and caspase-9-dependent effects of NP. Specific ER antagonists MPP and PHTPP potentiated the NP-induced loss of mitochondrial membrane potential and increase in lactate dehydrogenase (LDH) release whereas, ER agonists PPT and DPN inhibited these effects. RXR antagonist HX531 diminished the NP-evoked loss of mitochondrial membrane potential, the activity of caspase-3 and LDH release. In addition, exposure to NP inhibited ERα- and ERβ-specific immunofluorescence but stimulated RXR-specific immunolabeling in mouse hippocampal cells. In conclusion, our study demonstrated that the apoptotic and toxic actions of NP on neuronal cells in early development is accompanied by an impairment of ER- and stimulation of RXR-mediated signaling pathways. Taking into account NP-induced alterations in mRNA expression levels of particular types of RXRs, we suggest that NP affected mainly RXRα and RXRβ, but not RXRγ signaling.

Negative association between serum perfluorooctane sulfate concentration and bone mineral density in US premenopausal women: NHANES, 2005-2008

CONTEXT

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfate (PFOS) are used in a variety of products worldwide. However, the relationship among serum PFOA, PFOS concentration, bone mineral density (BMD), and the risk of fractures has never been addressed.

OBJECTIVES

The study examined the association among serum PFOA, PFOS concentration, and lumbar spine and total hip BMD in the general US population.

DESIGN AND PARTICIPANTS

We analyzed data on 2339 adults (aged ≧20 y) from the National Health and Nutrition Examination Survey conducted in 2005-2006 and 2007-2008 to determine the relationship among serum PFOA, PFOS concentration, and total lumbar spine and total hip BMD measured by dual-energy x-ray absorptiometry and history of fractures cross-sectionally.

RESULTS

After weighting for sampling strategy, a 1-U increase in the natural log-transformed serum PFOS level was associated with a decrease in total lumbar spine BMD by 0.022 g/cm(2) (95% confidence interval -0.038, -0.007; P = .006) in women not in menopause. There was no association among PFOA, PFOS concentration, and self-reported fracture in adults.

CONCLUSION

Serum PFOS concentration is associated with decreased total lumbar spine BMD in women not in menopause. However, the potential biological significance of this effect is marginal and subclinical in the general US population. Further studies are warranted to clarify the causal relationship between perfluorinated chemical exposure and BMD.

Dietary Aloe vera components' effects on cholesterol lowering and estrogenic responses in juvenile goldfish, Carassius auratus

Aloes are now considered a very interesting source of bioactive compounds among which phytosterols should play a major role. The present study is an attempt to investigate the hypocholesterolemic activity of Aloe vera associated with its impact on the reproductive status of juvenile goldfish. Therefore, the short- and long-term effects of feeding supplementary diet containing aloe components (20 mg aloe/g diet; 2%) on plasma lipids, plasma vitellogenin, and hepatic estrogen receptor α/β1 mRNA levels in goldfish were examined. Results of GC-MS for phytosterols show high abundance of β-sitosterol in freeze-dried powder of Aloe vera whole leaves. Moreover, a 2% aloe powder dietary supplement was not found estrogenic in juvenile goldfish after either 7- or 30-day treatment, but was consistent in plasma hypocholesterolemic effects following long-term exposure. The present data further support that plasma cholesterol modulation induced by phytosterols may not be related to estrogen-like activity.

Endocrine disruptors and bone metabolism

Bone microenvironment is a complex dynamic equilibrium between osteoclasts and osteoblasts and is modulated by a wide variety of hormones and osteocyte mediators secreted in response to physiological and pathological conditions. The rate of remodeling involves tight coupling and regulation of both cells population and is regulated by a wide variety of hormones and mediators such as parathyroid hormone, prostaglandins, thyroid hormone, sex steroids, etc. It is also well documented that bone formation is easily influenced by the exposure of osteoblasts and osteoclasts to chemical compounds. Currently, humans and wildlife animals are exposed to various environmental xenoestrogens typically at low doses. These compounds, known as endocrine disruptor chemicals (EDCs), can alter the systemic hormonal regulation of the bone remodeling process and the skeletal formation. This review highlights the effects of the EDCs on mammalian bone turnover and development providing a macro and molecular view of their action.