Bisphenol A exposure under metabolic stress induces accelerated cellular senescence in vivo in a p53 independent manner

The role of cellular senescence in metabolic diseases and the potential for senotherapeutic interventions

Cellular senescence represents an irreversible state of cell cycle arrest induced by various stimuli strongly associated with aging and several chronic ailments. In recent years, studies have increasingly suggested that the accumulation of senescent cells is an important contributor to the decline of organ metabolism, ultimately resulting in metabolic diseases. Conversely, the elimination of senescent cells can alleviate or postpone the onset and progression of metabolic diseases. Thus, a close relationship between senescent cells and metabolic diseases is found, and targeting senescent cells has emerged as an alternative therapy for the treatment of metabolic diseases. In this review, we summarize the role of cellular senescence in metabolic diseases, explore relevant therapeutic strategies for metabolic diseases by removing senescent cells, and provide new insights into the treatment of metabolic diseases.

Endocrine disruptors in plastics alter β-cell physiology and increase the risk of diabetes mellitus

Plastic pollution breaks a planetary boundary threatening wildlife and humans through its physical and chemical effects. Of the latter, the release of endocrine disrupting chemicals (EDCs) has consequences on the prevalence of human diseases related to the endocrine system. Bisphenols (BPs) and phthalates are two groups of EDCs commonly found in plastics that migrate into the environment and make low-dose human exposure ubiquitous. Here we review epidemiological, animal, and cellular studies linking exposure to BPs and phthalates to altered glucose regulation, with emphasis on the role of pancreatic β-cells. Epidemiological studies indicate that exposure to BPs and phthalates is associated with diabetes mellitus. Studies in animal models indicate that treatment with doses within the range of human exposure decreases insulin sensitivity and glucose tolerance, induces dyslipidemia, and modifies functional β-cell mass and serum levels of insulin, leptin, and adiponectin. These studies reveal that disruption of β-cell physiology by EDCs plays a key role in impairing glucose homeostasis by altering the mechanisms used by β-cells to adapt to metabolic stress such as chronic nutrient excess. Studies at the cellular level demonstrate that BPs and phthalates modify the same biochemical pathways involved in adaptation to chronic excess fuel. These include changes in insulin biosynthesis and secretion, electrical activity, expression of key genes, and mitochondrial function. The data summarized here indicate that BPs and phthalates are important risk factors for diabetes mellitus and support a global effort to decrease plastic pollution and human exposure to EDCs.

Potential effects of bisphenol A on diabetes mellitus and its chronic complications: A narrative review

Diabetes mellitus (DM) is a metabolic disease caused by multiple factors such as genetics, environment, and lifestyle. Bisphenol A (BPA), as one of the most common endocrine-disrupting chemicals (EDCs), has been strongly implicated in the development of type 2 diabetes mellitus (T2DM). BPA exposure is associated with target organ damage in DM and may exacerbate the progression of some chronic complications of DM. This paper reviews relevant epidemiological, in vivo, and in vitro studies to better understand BPA's potential risk associations and pathological mechanisms in several chronic diabetic complications.

The novel polyfluoroalkyl benzenesulfonate OBS exposure induces cell cycle arrest and senescence of rat pituitary cell GH3 via the p53/p21/RB pathway

Sodium p-perfluorous nonenoxybenzene sulfonate (OBS), an economical alternative to perfluorooctane sulfonate (PFOS) in multiple industrial fields, is widely detected in the environment. The toxicity of OBS has received increasing attention. Pituitary cells are components of the endocrine system and act as vital regulators of homeostatic endocrine balance. However, the effects of OBS on pituitary cells remain unknown. The present study explores the effects of OBS (0.5, 5, and 50μM) on GH3 rat pituitary cells after treatment for 24, 48, and 72h. We found that OBS significantly inhibited cell proliferation in GH3 cells with remarkable senescent phenotypes, including enhanced SA-β-gal activity and expression of senescence-associated secretory phenotype (SASP)-related genes, cell cycle arrest, and upregulation of the senescence-related proteins γ-H2A.X and Bcl-2. OBS caused significant cell cycle arrest of GH3 cells at the G1-phase and concomitantly downregulated the expression of some key proteins for the G1/S transition, including cyclin D1 and cyclin E1. Consistently, the phosphorylation of retinoblastoma (RB), which plays a central role in regulating the cell cycle, was prominently reduced after OBS exposure. Furthermore, OBS notably activated the p53-p21 signalling pathway in GH3 cells, as evidenced by increased p53 and p21 expressions, enhanced p53 phosphorylation, and augmented p53 nuclear import. To our knowledge, this study is the first to reveal that OBS triggers senescence in pituitary cells via the p53-p21-RB signalling pathway. Our study demonstrates a novel toxic effect of OBS in vitro, and provides new perspectives for understanding the potential toxicity of OBS.

Study of serum bisphenol-A and the mRNA of galactosidase beta 1 and tumor necrosis factor alpha in Egyptian patients with type 2 diabetes mellitus

Background

The pathogenesis of type 2 diabetes mellitus (T2DM) originates from multiple tissue defects. Environmental pollutants such like endocrine-disrupting chemicals (EDCs) have lately gotten special attention in triggering the metabolic abnormalities in relation to insulin resistance and T2DM. Bisphenol-A (BPA), which is one of the EDCs and simulates natural endogenous estrogens, has been implicated in the pathogenesis of several diseases, and, over the last decade, it has been revealed to have probable diabetogenic and obesogenic actions.

Aim

To study the environmental exposure of BPA by measuring its serum level together with the relative expression level of galactosidase beta 1 (GLB1), tumor necrosis alpha (TNF-α) mRNAs and malondialdehyde (MDA) as an oxidative stress marker determine the association of these markers with the glycemic control of Egyptian patients having T2DM.

Patients and methods

The present study was conducted on 90 participants categorized into group 1: 60 patients with T2DM and group 2: 30 subjects with normal glucose tolerance. Serum BPA levels were measured by enzyme-linked immunosorbent assay (ELISA) kit, and biochemical determinations were done by standard protocols. Because of the pro-oxidizing role of BPA, we measured serum level of malondialdehyde (MDA) as an oxidative stress marker. Peripheral blood mononuclear cells (PBMCs) were used for detecting the gene expression changes in GLB1 mRNA, a major marker of cellular senescence, and the mRNA of the proinflammatory cytokine, TNF-α.

Results

Serum levels of BPA in T2DM patients were significantly higher compared to their control group, and they were significantly and positively correlated to poor glycemic control and insulin resistance. T2DM patients showed significantly high serum MDA, mRNA levels of GLB1, and TNF-α. There was positive correlation between serum BPA levels and oxidative stress marker, senescence indicator, and inflammatory marker; however, there was no statistical significance for this correlation.

Conclusion

Our study demonstrates that there is a link between increased serum BPA levels, poor glycemic control, and insulin resistance in Egyptian patients with T2DM.

Bisphenol A Induces Accelerated Cell Aging in Murine Endothelium

Bisphenol A (BPA) is a widespread endocrine disruptor affecting many organs and systems. Previous work in our laboratory demonstrated that BPA could induce death due to necroptosis in murine aortic endothelial cells (MAECs). This work aims to evaluate the possible involvement of BPA-induced senescence mechanisms in endothelial cells. The β-Gal assays showed interesting differences in cell senescence at relatively low doses (100 nM and 5 µM). Western blots confirmed that proteins involved in senescence mechanisms, p16 and p21, were overexpressed in the presence of BPA. In addition, the UPR (unfolding protein response) system, which is part of the senescent phenotype, was also explored by Western blot and qPCR, confirming the involvement of the PERK-ATF4-CHOP pathway (related to pathological processes). The endothelium of mice treated with BPA showed an evident increase in the expression of the proteins p16, p21, and CHOP, confirming the results observed in cells. Our results demonstrate that oxidative stress induced by BPA leads to UPR activation and senescence since pretreatment with N-acetylcysteine (NAC) in BPA-treated cells reduced the percentage of senescent cells prevented the overexpression of proteins related to BPA-induced senescence and reduced the activation of the UPR system. The results suggest that BPA participates actively in accelerated cell aging mechanisms, affecting the vascular endothelium and promoting cardiovascular diseases.

The effect of environmental Bisphenol A exposure on breast cancer associated with obesity

Bisphenol A (BPA) is a widely used endocrine disrupter. Its environmental exposure is a causative factor of cell aging via decreasing telomerase activity, thus leading to shortening of telomere length. Epidemiological studies confirm positive associations between BPA exposure and the incidence of obesity and type 2 diabetes (T2DM). Increased urinary BPA levels in obese females are both significantly correlated with shorter relative telomere length and T2DM. BPA is a critically effective endocrine disrupter leading to poor prognosis via the obesity-inflammation-aromatase axis in breast cancer. Environmental BPA exposure contributes to the progression of both estrogen dependent and triple negative breast cancers. BPA is a positive regulator of human telomerase reverse transcriptase (hTERT) and it increases the expression of hTERT mRNA in breast cancer cells. BPA exposure can lead to tamoxifen resistance. Among patients treated with chemotherapy, those with persistent high telomerase activity due to BPA are at higher risk of death.

Bisphenol A regulates cytochrome P450 1B1 through miR-27b-3p and induces carp lymphocyte oxidative stress leading to apoptosis

Bisphenol A (BPA) is an industrial raw material widely used in water bottles, medical devices and food packaging, and is now ubiquitous in the environment. However, the effects of BPA on the toxicity of fish lymphocytes and the roles of microRNA (miRNA) in this process remain poorly understood. To explore the mechanism, we exposed carp spleen lymphocytes to BPA of 1, 5 and 10 nM for 24 h. The results showed that BPA induced carp lymphocyte apoptosis. BPA inhibited the expression of miR-27b-3p mRNA, thereby increasing the expression of cytochrome P450 1B1, increasing ROS levels, inhibiting SOD, CAT, GSH-PX activity, GSH content, promoting the accumulation of NOS and MDA. At the same time, BPA activated the mitochondrial apoptosis pathway, inhibited the expression of BCL-2, and promoted the expression of CytC, BAX, Caspase-9 and Caspase-3. Dual luciferase reporter system showed CYP1B1 is the target genes of miR-27b-3p and negatively regulated by it. Overexpression of miR-27b-3p partially reversed oxidative stress and apoptosis of carp spleen lymphocytes induced by BPA stimulation. Taken together, BPA exposure can target up regulate CYP1B1 expression by down regulating miR-27b-3p expression, thus causing oxidative stress and inducing apoptosis of carp spleen lymphocytes through mitochondrial pathway. Our study will provide theoretical basis for immunotoxicology mechanism research and environmental protection of BPA in fish.