Bisphenol A impairs macrophages through inhibiting autophagy via AMPK/mTOR signaling pathway and inducing apoptosis

Toxicological investigation of bisphenol A and its derivates on human breast epithelial (MCF-10A) cells

Bisphenols can enter the body, where they have potential adverse effects on human health, via different routes such as inhalation, dermally or orally. They are known as endocrine disrupting chemicals that activate signaling pathways by mimicking the estrogen actions. In this study, we aimed to investigate effects of bisphenol A (BPA), and its analogues bisphenol F (BPF) and bisphenol S (BPS) on MCF-10A cells and their impact mechanisms on autophagy, apoptosis and reduced glutathion levels. In comparison of the cytotoxic effects, while BPF and BPS showed dose-dependent high toxicity on MCF-10A cells, BPA exerted cytotoxic effects only at the highest doses. Caspase 3 and LC3B are strongly and positively correlated with BPF exposures while significant changes were not detected in the BPA and BPS applied groups. It was clearly observed that BPF and BPS displayed more toxic effects than BPA on human breast cells that are important targets for the bisphenols. These findings provide data for understanding the mechanisms for BPA, BPF and BPS-induced toxicity on human breast cells.

Lactoferrin influences atherosclerotic progression by modulating macrophagic AMPK/mTOR signaling-dependent autophagy

This study aimed to explore the role of lactoferrin (LTF) in atherosclerosis (AS) and its possible mechanisms. Human left coronary artery tissues were collected and divided into control (CON), coronary heart disease (CHD) and sudden coronary death (SCD) groups. Pathologic changes (including changes in the coronary plaque area, necrotic core, collagen fibers, and foam cell content) were observed. The LTF, P62, and 4-hydroxynonenal (4-HNE) expression levels were assessed. The ApoE-/- AS mouse model was established. The pathological changes and related protein levels were analyzed after autophagy inhibition. The foam cell model was constructed using an ox-LDL-induced human monocyte line, THP-1. The LTF, BECN1, LC3-II/I, AMP-activated protein kinase (AMPK)/the mammalian target of rapamycin (mTOR) pathway proteins, B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), and 4-HNE expressions were then detected after silencing of LTF or BECN1. Plaque stability was significantly lower in the SCD group compared to the non-SCD group (p < 0.05). LTF, P62 and 4-HNE levels in plaques increased as plaque stability decreased, and LTF was significantly correlated with plaque progression and autophagy levels. Autophagy inhibition by U0126 leads to the worsening of aortic luminal stenosis, increased necrotic core and foam cell deposits, decreased autophagosomes, reduced LTF expression, and upregulated P62 expression in AS mice. It was further demonstrated that LTF expression correlates with autophagy. LTF expression was increased in ox-LDL-treated THP-1 cells, and silencing BECN1 and/or LTF increased mTOR phosphorylation and 4-HNE levels, inhibited BECN1 and LC3 II expression and AMPK activation, and simultaneously decreased the Bcl-2/Bax ratio. LTF might alleviate AS pathology through accelerating the AMPK/mTOR pathway, and suggested that LTF may be a potential predictive molecule for AS.

Modulation of Autophagy on Cinnamaldehyde Induced THP-1 Cell Activation

Cinnamaldehyde (CIN), which is a cosmetic fragrance allergen regulated by the European Union, can induce allergic contact dermatitis in consumers, reducing their quality of life. Autophagy may be associated with the dendritic cell (DC) response to chemical sensitizers. We hypothesized that CIN would activate DCs through autophagy during skin sensitization. In this study, Tohoku Hospital Pediatrics-1 cells (THP-1 cells) were used as an in vitro DC model, and we evaluated the expression of cell activation markers, intracellular oxidative stress, and autophagy pathway-related genes in response to CIN in THP-1 cells. CIN exposure activated THP-1 cells, which presented increases in CD54 and CD86 expression and ROS generation. Transcriptomic analysis revealed that the genes that were differentially expressed after CIN stimulation were mostly associated with autophagy. The autophagy markers LC3B, p62, and ATG5 had upregulated mRNA and protein levels after CIN exposure. Furthermore, the effects of the autophagy inhibitor Baf-A1 and the autophagy activator rapamycin were investigated on CIN-treated cells. Pretreatment with Baf-A1 in THP-1 cells impaired autophagic flux and dramatically promoted cell activation and oxidative stress triggered by CIN. Conversely, rapamycin inhibited cell activation and the ROS content in CIN-challenged cells while increasing autophagy levels via a reduction in mTOR expression. These results suggest that the autophagy pathway has a pivotal influence on the regulation of CIN-induced activation in THP-1 cells, which provides new insight into the pathogenesis and precise therapeutic strategies for ACD.

Impact of Endocrine Disruptors on the Genitourinary Tract

Over the last decades, the human species has seen an increase in the incidence of pathologies linked to the genitourinary tract. Observations in animals have allowed us to link these increases, at least in part, to changes in the environment and, in particular, to an increasing presence of endocrine disruptors. These can be physical agents, such as light or heat; natural products, such as phytoestrogens; or chemicals produced by humans. Endocrine disruptors may interfere with the signaling pathways mediated by the endocrine system, particularly those linked to sex hormones. These factors and their general effects are presented before focusing on the male and female genitourinary tracts by describing their anatomy, development, and pathologies, including bladder and prostate cancer.

MiR-204 regulates autophagy and cell viability by targeting BDNF and inhibiting the NTRK2-dependent PI3K/Akt/mTOR pathway in a human granulosa cell line exposed to bisphenol A

Bisphenol A (BPA) is a widespread endocrine disruptor that mimics estrogen. The accumulation of BPA within the human body has been shown to be detrimental to ovarian function. However, few studies have focused on the specific mechanisms by which it causes harm to granulosa cells (GCs), pivotal ovarian cells that are responsible for the growth and function of oocytes. In vitro research was conducted using human GC lines (KGN cells). The cells were exposed to various concentrations of BPA (0.1, 1, 10, or 100 µM) for either 24 or 48 hours. Here, our findings indicate that 100 μM BPA inhibits KGN cell proliferation and promotes cell autophagy through inhibiting the PI3K/Akt/mTOR pathway. Interestingly, these effects could be partly reversed by an NTRK2 activator (LM22b-10). NTRK2 is the receptor for BDNF. Moreover, via the use of bioinformatics tools, miR-204 was predicted to target BDNF. Additionally, our findings confirmed that miR-204 has the ability to directly target BDNF through a luciferase assay. Downregulation of miR-204 abrogated the BPA exposure-mediated effects on proliferation and autophagy. Furthermore, the inhibition of miR-204 significantly reversed the downregulation of PI3K/Akt/mTOR pathway-related molecules. Similarly, we validated miR-204 as a novel miRNA involved in BPA-mediated damage to GC proliferation and autophagy, and our data provide the first in vitro evidence that increasing miR-204 expression and inhibiting the BDNF/NTRK2-mediated PI3K/Akt/mTOR signaling pathway are involved in the BPA-induced toxic effects in KGN cells.

Prenatal low-dose Bisphenol A exposure impacts cortical development via cAMP-PKA-CREB pathway in offspring

Bisphenol A (BPA) is a widely used plasticizer known to cause various disorders. Despite a global reduction in the use of BPA-containing products, prenatal exposure to low-dose BPA, even those below established safety limits, has been linked to neurological and behavioral deficits in childhood. The precise mechanisms underlying these effects remain unclear. In the present study, we observed a significant increase in the number of cortical neurons in offspring born to dams exposed to low-dose BPA during pregnancy. We also found that this prenatal exposure to low-dose BPA led to increased proliferation but reduced migration of cortical neurons. Transcriptomic analysis via RNA sequencing revealed an aberrant activation of the cAMP-PKA-CREB pathway in offspring exposed to BPA. The use of H89, a selective PKA inhibitor, effectively rescued the deficits in both proliferation and migration of cortical neurons. Furthermore, offspring from dams exposed to low-dose BPA exhibited manic-like behaviors, including hyperactivity, anti-depressant-like responses, and reduced anxiety. While H89 normalized hyperactivity, it didn't affect the other behavioral changes. These results suggest that the overactivation of PKA plays a causative role in BPA-induced changes in neuronal development. Our data also indicate that manic-like behaviors induced by prenatal low-dose BPA exposure may be influenced by both altered neuronal development and abnormal PKA signaling in adulthood.

Lycopene Regulates Macrophage Immune Response through the Autophagy Pathway Mediated by RIPK1

The effects of lycopene (LP) on macrophage immune responses were evaluated in this study. Compared with the control treatment, LP treatment significantly increased cell vitality, phagocytic activity, and chemokine production in RAW264.7 cells. Additionally, compared with the control treatment, 4 μM LP treatment significantly activated autophagy, enhanced mitochondrial membrane potential, and upregulated receptor-interacting protein kinase 1 (RIPK1), while necrostatin-1 significantly reversed these effects of LP. Furthermore, compared with that in the control group, RIPK1 was significantly upregulated in the 4 μM LP and 4 μM LP + spautin-1 groups, whereas p-mTOR levels were reduced. More importantly, compared with that in the control group, p62 was significantly downregulated, and Beclin1, LC3-II, and Atg7 were upregulated in the 4 μM LP group, while spautin-1 significantly reversed these effects of LP. These results confirm that LP activates the mTOR/Beclin1/LC3/p62 autophagy signaling pathway through RIPK1, thereby enhancing the immune response of macrophages.

The Protective Effect of Gallic Acid Against Bisphenol A-Induced Ovarian Toxicity and Endocrine Disruption in Female Rats

Purpose: This study aimed to investigate the protective effects of gallic acid (GA) against ovarian damage induced by bisphenol A (BPA) exposure in female rats. We evaluated whether GA can mitigate the adverse effects of BPA on ovarian structure, inflammatory markers, oxidative stress, apoptosis, and reproductive hormone levels. Methods: Thirty-two female rats were categorized into four groups: control, GA, BPA, and GA+BPA. Histopathological evaluations of ovarian tissue were performed using hematoxylin-eosin staining. The immunohistochemical analysis was conducted for inflammatory, oxidative DNA damage, and apoptotic markers (Tumor necrosis factor alpha [TNFα], cyclooxygenase-2 [COX2], interleukin-1 beta [IL-1β], 8-hydroxydeoxyguanosine [8-OHdG], and caspase 3). Oxidative stress was assessed by measuring malondialdehyde and superoxide dismutase levels. Furthermore, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen, and progesterone levels were quantified using enzyme-linked immunosorbent assay. Results: Histopathological outcomes revealed that BPA significantly induced follicular degeneration, which was effectively mitigated by GA treatment (P < 0.05). Immunohistochemical analysis highlighted the exacerbation of inflammatory responses and oxidative DNA damage and apoptosis (TNFα, COX-2, IL-1β, 8-OHdG, and caspase 3) in BPA-exposed tissues, which were reduced in the presence of GA (P < 0.05). The assessment of oxidative stress demonstrated that GA could significantly decrease lipid peroxidation and partially restore antioxidant defense mechanisms disrupted by BPA (P < 0.05). Hormonal profiling indicated that BPA exposure altered the levels of FSH, LH, estrogen, and progesterone, with GA treatment showing a capacity to modulate these changes, especially in progesterone levels (P < 0.05). Conclusions: The findings suggest that GA exhibits protective properties against BPA-induced ovarian damage through its antioxidative and anti-inflammatory activities, alongside its ability to modulate hormonal imbalances. This research underscores the therapeutic potential of GA in safeguarding reproductive health against environmental toxicants.

Deciphering the molecular mechanism of NLRP3 in BPA-mediated toxicity: Implications for targeted therapies

Bisphenol-A (BPA), a pervasive industrial chemical used in polymer synthesis, is found in numerous consumer products including food packaging, medical devices, and resins. Detectable in a majority of the global population, BPA exposure occurs via ingestion, inhalation, and dermal routes. Extensive research has demonstrated the adverse health effects of BPA, particularly its disruption of immune and endocrine systems, along with genotoxic potential. This review focuses on the complex relationship between BPA exposure and the NOD-like receptor protein 3 (NLRP3) inflammasome, a multiprotein complex central to inflammatory disease processes. We examine how BPA induces oxidative stress through the generation of intracellular free radicals, subsequently activating NLRP3 signaling. The mechanistic details of this process are explored, including the involvement of signaling cascades such as PI3K/AKT, JAK/STAT, AMPK/mTOR, and ERK/MAPK, which are implicated in NLRP3 inflammasome activation. A key focus of this review is the wide-ranging organ toxicities associated with BPA exposure, including hepatic, renal, gastrointestinal, and cardiovascular dysfunction. We investigate the immunopathogenesis and molecular pathways driving these injuries, highlighting the interplay among BPA, oxidative stress, and the NLRP3 inflammasome. Finally, this review explores the emerging concept of targeting NLRP3 as a potential therapeutic strategy to mitigate the organ toxicities stemming from BPA exposure. This work integrates current knowledge, emphasizes complex molecular mechanisms, and promotes further research into NLRP3-targeted interventions.

Triclosan and its alternatives, especially chlorhexidine, modulate macrophage immune response with distinct modes of action

Since European regulators restricted the use of bacteriocidic triclosan (TCS), alternatives for TCS are emerging. Recently, TCS has been shown to reprogram immune metabolism, trigger the NLRP3 inflammasome, and subsequently the release of IL-1β in human macrophages, but data on substitutes is scarce. Hence, we aimed to examine the effects of TCS compared to its alternatives at the molecular level in human macrophages. LPS-stimulated THP-1 macrophages were exposed to TCS or its substitutes, including benzalkonium chloride, benzethonium chloride, chloroxylenol, chlorhexidine (CHX) and cetylpyridinium chloride, with the inhibitory concentration (IC10-value) of cell viability to decipher their mode of action. TCS induced the release of the pro-inflammatory cytokine TNF and high level of IL-1β, suggesting the activation of the NLRP3-inflammasome, which was confirmed by non-apparent IL-1β under the NLRP3-inhibitor MCC950 treatment d. While IL-6 release was reduced in all treatments, the alternative CHX completely abolished the release of all investigated cytokines. To unravel the underlying molecular mechanisms, we used untargeted LC-MS/MS-based proteomics. TCS and CHX showed the strongest cellular response at the protein and signalling pathway level, whereby pathways related to metabolism, translation, cellular stress and migration were mainly affected but to different proposed modes of action. TCS inhibited mitochondrial electron transfer and affected phagocytosis. In contrast, in CHX-treated cells, the translation was arrested due to stress conditions, resulting in the formation of stress granules. Mitochondrial (e.g. ATP5F1D, ATP5PB, UQCRQ) and ribosomal (e.g. RPL10, RPL35, RPS23) proteins were revealed as putative key drivers. Furthermore, we have demonstrated the formation of podosomes by CHX, potentially involved in ECM degradation. Our results exhibit modulation of the immune response in macrophages by TCS and its substitutes and illuminated underlying molecular effects. These results illustrate critical processes involved in the modulation of macrophages' immune response by TCS and its alternatives, providing information essential for hazard assessment.

Gestational exposure to bisphenol AF causes endocrine disorder of corpus luteum by altering ovarian SIRT-1/Nrf2/NF-kB expressions and macrophage proangiogenic function in mice

Bisphenol AF (BPAF) is extensively used in industrial production as an emerging substitute for the earlier-used bisphenol A (BPA). Studies have found that BPAF had stronger estrogenic activities than BPA. However, the effects of BPAF on the luteal function of pregnancy and its possible mechanisms are largely unknown. In this study, pregnant mice were orally administered 3.0 and 30 mg/kg/day of BPAF from gestational day (GD) 1 to 8, and samples were collected on GD 8 and GD 19. Results showed that maternal exposure to BPAF impaired embryo implantation and reduced ovarian weight, and interfered with steroid hormone secretion, and decreased the numbers and areas of corpus luteum. BPAF treatment significantly down-regulated expression levels of ovarian Star, Cyp11a, Hsd3b1, and Cyp19a1 mRNA and CYP19a1 and ERα proteins. BPAF also disrupted markers of redox/inflammation key, including silent information regulator of transcript-1 (SIRT-1), nuclear factor erythroid 2-related factor 2 (Nrf2), and nuclear factor kappa-B (NF-ĸB) expressions along with reduced ovarian antioxidant (CAT and SOD) capacity, enhanced oxidant (H2O2 and MDA) and inflammatory factor (Il6 and Tnfa) activities. Furthermore, BPAF exposure inhibited macrophages with a pro-angiogenic phenotype that specifically expressed TIE-2, accompanied by inhibition of angiogenic factors (HIF1a, VEGFA, and Angpt1) and promotion of anti-angiogenic factor Ang-2 to suppress luteal angiogenesis. In addition, BPAF administration also induced luteolysis and apoptosis by up-regulation of COX-2, BAX/BCL-2, and Cleaved-Caspase-3 protein. Collectively, our current data demonstrated that gestational exposure to BPAF caused luteal endocrine disorder by altering ovarian SIRT-1/Nrf2/NF-kB expressions and macrophage proangiogenic function in mice.

Effects of Allium macrostemon Bunge Extract on Adipose Tissue Inflammation and Hepatic Endoplasmic Reticulum Stress in High-Fat Diet-Fed and Bisphenol A-Treated C57BL/6N Mice

The simultaneous exposure to a high-fat (HF) diet and to bisphenol A (BPA) from delivered foods and food-delivery containers is on the rise in humans, according to the increased frequency of food delivery during the COVID-19 pandemic. This co-exposure could cause harmful tissue toxicity in the human body. Here, the preventive effect of Allium macrostemon Bunge (AM) extract against dysfunction in adipose tissue and the liver under co-exposure to BPA and an HF diet was examined using mice. C57BL/6N mice were divided into four groups (n = 6 or 7/group) according to diet and treatment: control diet with vehicle (CON), HF diet with vehicle (HF), HF diet with an oral injection of BPA (HF + BP), and HF diet with an oral injection of BPA and AM extract (HF + BP + AM). HF feeding increased body weight gain compared to CON feeding, while BP + HF and BP + HF + AM feeding suppressed body weight gain compared with HF feeding. The BP + HF group had lower body weight than the HF group, but the two groups had similar epididymal fat mass. The HF + BP + AM group showed lower pro-inflammatory gene expression levels in adipose tissue and epididymal fat mass compared to the HF + BP group. Altered endoplasmic reticulum (ER) stress response in the liver was partly observed in the HF + BP group, as shown by increased total phosphorylated Jun N-terminal kinase protein levels compared to those in the HF group. In addition, ecdysterone 25-O-β-D-glucopyranoside and 6-gingerol were identified in AM extract by mass spectrometry and molecular networking analysis. In summary, the AM extract diminished adipose tissue inflammation and hepatic ER stress in an HF diet and BPA co-exposure condition. To utilize AM as a potential food component to alleviate the harmful effect of an HF diet and BPA exposure, further research investigating the specific impact of AM extract supplementation using additional experimental groups or various treatment doses is warranted.

Endocrine-disrupting chemicals and autoimmune diseases

Endocrine-disrupting chemicals (EDCs) widely exist in people's production and life which have great potential to damage human and animal health. Over the past few decades, growing attention has been paid to the impact of EDCs on human health, as well as immune system. So far, researchers have proved that EDCs (such as bisphenol A (BPA), phthalate, tetrachlorodibenzodioxin (TCDD), etc.) affect human immune function and promotes the occurrence and development of autoimmune diseases (ADs). Therefore, in order to better understand how EDCs affect ADs, we summarized the current knowledge about the impact of EDCs on ADs, and elaborated the potential mechanism of the impact of EDCs on ADs in this review.

Inhibition of VDAC1 prevents oxidative stress and apoptosis induced by bisphenol A in spermatogonia via AMPK/mTOR signaling pathway

Bisphenol A (BPA), one of the main components of industrial products, is clinically associated with the increased male infertility rate. However, the underlying molecular mechanism of the BPA-resulted reproductive toxicity is not fully elucidated. Voltage-dependent anion channel 1 (VDAC1) is a pore protein and located at the outer mitochondrial membrane. As a mitochondrial gatekeeper, VDAC1 controls the release of reactive oxygen species (ROS) and the metabolic and energetic functions of mitochondria, and serves as a critical player in mitochondrial-mediated apoptosis. Herein, we explored the role of VDAC1 in BPA-induced apoptosis of spermatogonia. The results showed that BPA increased spermatogonia cell line GC-1 spg cell apoptosis and intracellular ROS level, and suppressed AMPK/mTOR signaling pathway at a dose of 80 μM for 48 hr. Lentivirus-mediated short hairpin RNA targeting VDAC1 (Lv-shVDAC1) silenced VDAC1 expression and enhanced BPA-restricted cell viability. Knockdown of VDAC1 inhibited the apoptosis of BPA-treated GC-1 spg cells determined by with changes of the expressions of pro-apoptotic and anti-apoptotic proteins. Knockdown of VDAC1 also alleviated the BPA-triggered intracellular ROS generation and oxidative stress. Moreover, silence of VDAC1 increased AMPKα1/2 phosphorylation and suppressed mTOR phosphorylation under BPA exposure. Dorsomorphin, an AMPK inhibitor, partially abolished the effects of VDAC1 gene silencing on BPA-stimulated GC-1 spg cells. In conclusion, inhibition of VDAC1 attenuated the BPA-induced oxidative stress and apoptosis and promoted the cell viability in spermatogonia through modulating AMPK/mTOR signaling pathway.

Bisphenols A and F, but not S, induce apoptosis in bovine granulosa cells via the intrinsic mitochondrial pathway

With the gradual decline in global fertility rates, there is a need to identify potential contributing factors, their mechanisms of actions and investigate possible solutions to reverse the trend. Endocrine disrupting compounds (EDCs), such as bisphenol A (BPA), are environmental toxicants that are known to negatively impact reproductive functions. As such, the use of BPA in the manufacturing industry has slowly been replaced by analogs, including bisphenol S (BPS) and bisphenol F (BPF), despite limited knowledge available regarding their impact on health and their safety. The following study investigates the effects of BPA, BPS and BPF at a concentration of 0.5 μg/mL and 50 μg/mL on bovine granulosa cell apoptosis, with the ultimate goal of determining how they may impact oocyte competence and, thus, overall fertility. The underlying hypothesis is that bisphenols disrupt the granulosa cell environment surrounding the oocyte inducing excessive apoptosis via the intrinsic mitochondrial pathway. To test this hypothesis, apoptosis was measured following a time- and dose-dependent exposure to all three bisphenols by flowcytometry paired with annexin V/PI staining as well as by quantification of key genes belonging to the intrinsic apoptotic pathway both at the mRNA and protein levels. The results of this study report that BPA and BPF reduce cell viability through reduced cell counts and increased apoptosis. This increase is due, in part, to the induction of apoptotic genes of the intrinsic pathway of apoptosis. Additionally, this study also suggests that BPS may not act on the intrinsic mitochondrial apoptotic pathway in bovine granulosa cells. Overall, this study allows us to establish potential apoptotic pathways activated by bisphenols as well as compare the relative apoptotic activities of BPA to its most widespread analogs.