Chronic Exposure to Environmental Level Phenanthrene Induces Non-Obesity-Dependent Insulin Resistance in Male Mice

Gestational Exposure to Phenanthrene Induces Superfluous Fibrosis and Calcification and Metabolic Imbalance of the Placenta in Mice

The placenta is a vital organ that facilitates maternal-fetal circulation, ensuring proper fetal development. Phenanthrene (Phe), a typical low-molecular-weight polycyclic aromatic hydrocarbon, is widely present in the environment and food. In this study, pregnant mice were exposed to Phe (0, 0.6, 6, and 60 μg/kg of body weight) via gavage every 3 days from pregnancy day 0.5 (PGD 0.5) for a total of six exposures during pregnancy. Placentas were collected on PGD of 18.5 for analysis. The results showed that Phe exposure altered placental structure and function, inducing trophoblast thickening at low doses (0.6 μg/kg) but thinning at higher doses (6 and 60 μg/kg), reducing blood cell density in the placental labyrinth, disrupting metabolite composition, causing oxidative damage, and leading to excessive fibrosis and calcification. Molecular analysis revealed that PCNA was significantly upregulated in the 0.6 μg/kg group and downregulated in 6 and 60 μg/kg groups, indicating an initial compensatory proliferative response at low doses and impaired placental proliferation at higher doses, while Bad was abnormally accumulated in trophoblasts and dose-dependently upregulated, along with decline in antioxidant capacity. Meanwhile, increases in protein levels of TGF-β1, Smad2, p-Smad2, Smad1/5/9, p-Smad1/5/9, BMP2, TIMP1, Runx2, Collagen I, and SMA, and a decrease in MMP1 level was observed. These findings suggested that Phe exposure during pregnancy induced activation of the TGF-β/Smad2 pathway and BMP2/Smad1/5/9/Runx2 pathway, which might further lead to excessive fibrosis and calcification. The abnormally increased fibrosis and calcification, together with the oxidative damage, further elevated cellular apoptosis, destroyed the structure of the placenta, and reduced blood cell counts, impairing placental exchange efficiency and leading to systemic metabolic imbalances, which might further impair the health of their offspring.

The role of telomere shortening in ambient ozone exposure-related insulin resistance

BACKGROUND

Ozone (O3) exposure and telomere shortening are associated with insulin resistance (IR). However, the role of telomere shortening in ambient O3 exposure-related IR is largely unclear.

METHODS

The Henan Rural Cohort recruited participants and performed a random forest method to estimate residential O3 concentration. IR was reflected by homeostasis model assessment-IR, quantitative insulin sensitivity check index, triglyceride and glucose index, etc. Generalized linear model, quantile regression model, and mediation effects analysis were utilized to assess the associations of O3 exposure and relative telomere length (RTL) with longitudinal IR markers and their change rates. Furthermore, the role of telomere homeostasis in O3-exposure-induced IR in vivo and in vitro experiments was verified.

RESULTS

O3 exposure was positively associated with longitudinal IR. The proportions of RTL mediated associations between O3 exposure and longitudinal IR markers ranged from 11.92 % to 60.36 %. O3-exposed mice exhibited a higher glucose load, upregulation of GSK-3β and G-6-Pase expression at mRNA levels, glycogen accumulation reduction, telomere shortening, and decreased telomerase reverse transcriptase activity relative to air-exposed mice. In vitro experiments reveal that overexpression of TERT in HepG2 cells up-regulated G-6-Pase mRNA expression level.

CONCLUSIONS

Impaired telomere homeostasis may be involved in O3 exposure-related IR via inhibition of glycogen synthesis and acceleration of gluconeogenesis and the specific mechanisms are still further elucidated.

Longitudinal joint effects of polycyclic aromatic hydrocarbons exposure and genetic susceptibility on fasting plasma glucose: A prospective cohort study of general Chinese urban adults

The effects of environmental polycyclic aromatic hydrocarbons (PAHs) exposure on glycemic regulation and the underlying genetic mechanism were still unclear. This study aimed to analyze the longitudinal joint effects of PAHs exposure and genetic susceptibility on fasting plasma glucose (FPG) through a longitudinal study. We included 4104 observations (2383 baseline participants and 1721 6-year follow-up participants) from Wuhan-Zhuhai cohort. Ten urinary PAHs metabolites and FPG were measured at both baseline and follow-up. We constructed the polygenic risk scores (PRS) of FPG from the corresponding genome-wide association studies. Linear mixed models were used to explore the associations of urinary PAHs metabolites or FPG-PRS on FPG levels in the repeated-measure analysis. Besides, the longitudinal relationships of urinary PAHs metabolites, FPG-PRS, and their joint effects on FPG change over 6 years were evaluated by linear regression models. Compared with participants with persistent low levels of urinary total PAHs metabolites, hydroxynaphthalene, and hydroxyphenanthrene, participants with persistent high levels had average decreases of 0.173, 0.188, and 0.263 mmol/L for FPG change over 6 years, respectively. Each 1-unit increase of FPG-PRS was associated with a 0.531 mmol/L for FPG change over 6 years. Besides, compared with participants with high FPG-PRS and persistent low levels of urinary total hydroxynaphthalene, hydroxyfluorene, and hydroxyphenanthrene, participants with low FPG-PRS and persistent high levels had average decreases of 0.322, 0.567, and 0.419 mmol/L for FPG change over 6 years. Our findings demonstrated that high-level PAHs exposure was longitudinally associated with an average decrease of FPG over 6 years, and low FPG genetic risk can enhance the above associations. Our findings emphasized the hypoglycemic effect of PAHs exposure, shed new light on the complex effects between PAHs exposure and genetic factors in the prevention of high FPG, and might provide some clues for the development of potential hypoglycemic agents.

Phenanthrene-induced hyperuricemia with intestinal barrier damage and the protective role of theabrownin: Modulation by gut microbiota-mediated bile acid metabolism

Hyperuricemia is prevalent globally and potentially linked to environmental pollution. As a typical persistent organic pollutant, phenanthrene (Phe) poses threats to human health through biomagnification. Although studies have reported Phe-induced toxicities to multiple organs, its impact on uric acid (UA) metabolism remains unclear. In this study, data mining on NHANES 2001-2016 indicated a positive correlation between Phe exposure and the occurrence of hyperuricemia in population. Subsequently, adolescent Balb/c male mice were orally exposed to Phe at a dosage of 10 mg/kg bw every second day for 7 weeks, resulting in dysfunction of intestinal UA excretion and disruption of the intestinal barrier. Utilizing intestinal organoids, 16S rRNA sequencing of gut microbiota, and targeted metabolomic analysis, we further revealed that an imbalance in bile acid metabolism derived from gut microbiota might mediate the intestinal barrier damage. Additionally, the tea extract theabrownin (TB) effectively improved Phe-induced hyperuricemia and intestinal dysfunction at a dose of 320 mg/kg bw per day. In conclusion, this study demonstrates that Phe exposure is positively associated with hyperuricemia and intestinal damage, which provides new insights into the toxic effects induced by Phe. Furthermore, the present study proposes that supplementation with TB would be a healthy and effective improvement strategy for patients with hyperuricemia and intestinal injury caused by environmental factors.

Induction of insulin resistance in female mice due to prolonged phenanthrene exposure: Unveiling the low-dose effect and potential mechanisms

Phenanthrene (Phe) is a commonly occurring polycyclic aromatic hydrocarbon (PAH) found in various food sources and drinking water. Previous studies have shown that long-term exposure to Phe in male mice leads to insulin resistance in a dose-dependent manner. However, the effect of Phe on glucose homeostasis in female mice remains unknown. To address this knowledge gap, female Kunming mice were exposed to Phe through their drinking water at concentrations of 0.05, 0.5, and 5 ng/mL. After 270 d of exposure, we surprisingly discovered a low-dose effect of Phe on insulin resistance in female mice, which differed from the effect observed in male mice and showed sexual dimorphism. Specifically, insulin resistance was only observed in the 0.05 ng/mL treatment, and this low-dose effect was also reflected in the concentration of Phe in white adipose tissue (WAT). Differences in metabolic enzyme activities in the liver may potentially explain this effect. The observed sexual dimorphism in Phe exposure could be attributed to variations in estrogen (E2) level and estrogen receptor beta (ERβ) expression in WAT. These findings highlight the association between environmental factors and the development of insulin resistance, emphasizing the pathogenic effect of even low doses of Phe. Moreover, sex dependent-effect should be given more attention when studying the toxic effects of environmental pollutants.

Identification and Validation of Oxidative Stress-Related Biomarkers for Bronchopulmonary Dysplasia

The objective of this study was to identify and characterize oxidative stress (OS)-related biomarkers in bronchopulmonary dysplasia (BPD) through a combination of bioinformatics analyses and wet experiments. The study utilized the Gene Expression Omnibus database to obtain the mRNA expression profile dataset GSE32472. Differential expression analysis and functional enrichment analysis were employed to investigate the role of OS-related genes in BPD. Gene Ontology Function Enrichment Analysis and Gene Set Enrichment Analysis were conducted to understand the mechanisms behind the signature. Protein-protein interaction analysis to identify hub genes in BPD, and predictions were made for microRNAs (miRNAs), transcription factors (TFs), and potential medications targeting these genes. CIBERSORT was utilized to investigate the correlation between hub genes and the infiltration of immune cells. Hub genes were ultimately determined and confirmed using expression analysis, correlation analysis, receiver operating characteristic (ROC) analysis, and quantitative real-time PCR (qRT-PCR). A novel OS-related gene signature (ARG1, CSF3R, IL1R1, IL1R2, MMP9, RETN, S100A12, and SOCS3) was constructed for the prediction of BPD. We identified 18 miRNAs, 14 TFs, and 30 potential medications targeting these genes. ROC analysis further validated that these genes could diagnose BPD with high specificity and sensitivity. The qRT-PCR revealed that IL1R1 and ARG1 were highly expressed in the lung tissue of the model group, while the expressions of RETN, SOCS3, IL1R2, and MMP9 were decreased. This study demonstrated that ARG1, CSF3R, IL1R1, IL1R2, MMP9, RETN, S100A12, and SOCS3 may serve as potential diagnostic biomarkers in BPD. Furthermore, a significant association between IL1R1 and the pathogenesis of BPD is observed.

Adverse impact of phthalate and polycyclic aromatic hydrocarbon mixtures on birth outcomes: A metabolome Exposome-Wide association study

It has been well-investigating that individual phthalates (PAEs) or polycyclic aromatic hydrocarbons (PAHs) affect public health. However, there is still a gap that the mixture of PAEs and PAHs impacts birth outcomes. Through innovative methods for mixtures in epidemiology, we used a metabolome Exposome-Wide Association Study (mExWAS) to evaluate and explain the association between exposure to PAEs and PAHs mixtures and birth outcomes. Exposure to a higher level of PAEs and PAHs mixture was associated with lower birth weight (maximum cumulative effect: 143.5 g) rather than gestational age. Mono(2-ethlyhexyl) phthalate (MEHP) (posterior inclusion probability, PIP = 0.51), 9-hydroxyphenanthrene (9-OHPHE) (PIP = 0.53), and 1-hydroxypyrene (1-OHPYR) (PIP = 0.28) were identified as the most important compounds in the mixture. In mExWAS, we successfully annotated four overlapping metabolites associated with both MEHP/9-OHPHE/1-OHPYR and birth weight, including arginine, stearamide, Arg-Gln, and valine. Moreover, several lipid-related metabolism pathways, including fatty acid biosynthesis and degradation, alpha-linolenic acid, and linoleic acid metabolism, were disturbed. In summary, these findings may provide new insights into the underlying mechanisms by which PAE and PAHs affect fetal growth.

Oral exposure to phenanthrene during gestation disorders endocrine and spermatogenesis in F1 adult male mice

Phenanthrene (Phe), a typical low-molecular-weight polycyclic aromatic hydrocarbon (PAH) of three benzene rings, is one of the most abundant PAHs detected in daily diets. Pregnant women and infants are at great risk of Phe exposure. In the present study, Phe was administered to pregnant mice at a dose of 0, 60, or 600 μg/kg body weight six times, and the F1 male mice showed significant reproductive disorders: the testicular weight and testis somatic index were significantly reduced; the levels of serum testosterone, GnRH and SHBG were increased, while the FSH levels were reduced; histological analysis showed that the amount of Sertoli cells and primary spermatocytes in seminiferous tubules was increased, while the amount of secondary spermatocytes and spermatids were decreased in Phe groups. The protein levels of PCNA and androgen receptor were reduced. Differently expressed genes in the testis screened by RNA sequence were enriched in antioxidant capacity, reproduction et al.. Further biochemical tests confirmed that the antioxidant capacity in the F1 testis was significantly inhibited by treatment with Phe during pregnancy. Those results suggested that gestational Phe exposure disordered hypothalamic-pituitary-gonadal (HPG) hormones on the one hand, and on the other hand reduced testicular antioxidant capacity and further arrested cell cycle in F1 adult male mice, which co-caused the inhibition of spermatogenesis.

Environmental dose of 16 priority-controlled PAHs induce endothelial dysfunction: An in vivo and in vitro study

Polycyclic aromatic hydrocarbons (PAHs) exposure is related to the occurrence of cardiovascular diseases (CVDs). Endothelial dysfunction is considered an initial event of CVDs. To confirm the relationship of PAHs exposure with endothelial dysfunction, 8-week-old male SD rats and primary human umbilical vein endothelial cells (HUVECs) were co-treated with environmental doses of 16 priority-controlled PAHs for 90 d and 48 h, respectively. Results showed that 10× PAHs exposure remarkably raised tumor necrosis factor-α and malonaldehyde levels in rat serum (p < 0.05), but had no effects on interleukin-8 levels and superoxide dismutase activity. The expressions of SIRT1 in HUVECs and rat aorta were attenuated after PAHs treatment. Interestingly, PAHs exposure did not activate the expression of total endothelial nitric oxide synthase (eNOS), but 10× PAHs exposure significantly elevated the expression of phosphorylated eNOS (Ser1177) in HUVECs and repressed it in aortas, accompanied with raised nitrite level both in serum and HUVECs by 48.50-253.70 %. PAHs exposure also led to the augment of endothelin-1 (ET-1) levels by 19.76-38.54 %, angiotensin (Ang II) levels by 20.09-39.69 % in HUVECs, but had no effects on ET-1 and Ang II levels in serum. Additionally, PAHs exposure improved endocan levels both in HUVECs and serum by 305.05-620.48 % and stimulated the THP-1 cells adhered to HUVECs (p < 0.05). After PAHs treatment, the smooth muscle alignment was disordered and the vascular smooth muscle locally proliferated in rat aorta. Notably, the systolic blood pressure of rats exposed to 10× PAHs increased significantly compared with the control ones (131.28 ± 5.20 vs 116.75 ± 5.33 mmHg). In summary, environmental chronic PAHs exposure may result in endothelial dysfunction in SD rats and primary HUVECs. Our research can confirm the cardiovascular damage caused by chronic exposure to PAHs and provide ideas for the prevention or intervention of CVDs affected by environmental factors.

Association between polycyclic aromatic hydrocarbon exposure and blood lipid levels: the indirect effects of inflammation and oxidative stress

Although previous studies have indicated polycyclic aromatic hydrocarbons (PAHs) as cardiovascular health risk factors, evidence linking exposure to PAHs and blood lipids is still lacking, and the mechanism remains largely unknown. In this study, we evaluated the association between human internal exposure to PAHs and blood lipid levels in adults, as well as the indirect effects of inflammation and oxidative stress. The internal exposure of PAHs was assessed by determining serum PAHs and their hydroxylated metabolites (OH-PAHs) in the paired urine samples. Multivariable linear regression results demonstrated significant positive associations of individual PAHs and OH-PAHs with blood lipid biomarkers. The Bayesian kernel machine regression model revealed positive joint effects of PAH internal exposure on the fasting blood glucose, low-density lipoprotein cholesterol, total cholesterol, and total triglyceride, as well as an increased ratio of apolipoprotein B to apolipoprotein A1. In evaluating individual effects, serum phenanthrene played the most significant role in the association of increased PAH exposure with elevated fasting blood glucose. Quantile g-computation demonstrated the significant change in the levels of apolipoprotein B, ratio of apolipoprotein B to apolipoprotein A1, low-density lipoprotein cholesterol, and total cholesterol per quartile increase in PAH internal exposure. The restricted cubic spline analysis demonstrated the non-linear relationship between individual PAHs and OH-PAHs on blood lipid biomarkers. The mediation analysis indicated that PAH exposure may affect blood lipids not directly, but rather indirectly through intermediate inflammation and oxidative stress. The results demonstrated a significant association between increased PAH exposure levels and elevated blood lipids, highlighting the indirect effects of inflammation and oxidative stress.

Sex-specific thyroid disruption caused by phenanthrene in adult zebrafish (Danio rerio)

Polycyclic aromatic hydrocarbons (PAHs) are well-known contaminants with widespread distribution in environment and food. Phenanthrene is one of the most abundant PAHs in food and aquatic environment and generates reproductive and developmental toxicity in zebrafish. Nonetheless, whether phenanthrene caused sex-specific thyroid disruption in adult zebrafish is unclear. To determine this, adult zebrafish (male and female) were treated with phenanthrene (0, 0.85, 8.5, and 85 μg/L) for 60 days. After the treatment period, we assessed the concentrations of thyroid hormones (THs) and expression levels of genes in the hypothalamic-pituitary-thyroid (HPT) axis. The results showed that phenanthrene exposure can lead to thyroid disruption in both male and female zebrafish. Exposure to phenanthrene dramatically reduced the levels of L-thyroxine (T4) and L-triiodothyronine (T3) in both male and female zebrafish, with a similar trend in both. However, the genes expression profiles of hypothalamic-pituitary-thyroid (HPT) axis were sex-specific. In all, the present study demonstrated that phenanthrene exposure could result in sex-specific thyroid disruption in adult zebrafish.

Black phosphorus quantum dots cause glucose metabolism disorder and insulin resistance in mice

Black phosphorus quantum dots (BPQDs) are considered to have wide application prospects due to their excellent properties. However, there is no study on the effect of BPQDs on glucose metabolism. In this study, blood glucose was significantly increased when mice were continuously intragastrically administered 0.1 and 1 mg/kg bw BPQDs. The blood glucose level of the mice was elevated from Day 7 to Day 28. BPQD exposure also decreased the area under the curve (AUC) of the oral glucose tolerance test (OGTT). After exposure, the pancreas somatic index was increased. Moreover, the serum insulin and glucagon levels were elevated and the relative area of islet β cells was increased in BPQD-exposed mice, while insulin signaling cascades were reduced in muscle tissues. In summary, our study demonstrated for the first time that BPQD exposure induces glucose disorder and insulin resistance in muscle, which is helpful to understand the biosafety of black phosphorus nanomaterials and promote the sustainable development of nanotechnology.

Long-term exposure to environmental levels of phenanthrene induces emaciation-thirst disease-like syndromes in female mice

Phenanthrene (Phe) is a polycyclic aromatic hydrocarbon widely present in foods and drinking water. To explore the detrimental effects of Phe on body metabolism, female Kunming mice were treated with Phe in drinking water at concentrations of 0.05, 0.5 and 5 ng/mL. After exposure for 270 d, the animals exhibited dose-dependent reduced body weight and increased water consumption. The dose-dependent accumulation of Phe in the brain decreased hypothalamic neuron numbers, upregulated hypothalamic expression of anaplastic lymphoma kinase, elevated norepinephrine levels in white adipose tissue (WAT) and further activated lipolysis in WAT, leading to a reduction in fat mass. Brown adipose tissue formation was reduced, accompanied by the inhibition of the bone morphogenetic protein signaling pathway. A simultaneous reduced serum levels of antidiuretic hormone (arginine vasopressin) might be one of the reasons for increased water consumption. The present results indicate an environmental etiology and prevention way for the development of emaciation-thirst disease.

Prenatal exposure to a mixture of PAHs causes the dysfunction of islet cells in adult male mice: Association with type 1 diabetes mellitus

Polycyclic aromatic hydrocarbons (PAHs) have been detected throughout the human body. Whether exposure to PAHs is associated with the incidence of type 1 diabetes mellitus should be investigated. To this end, pregnant mice were exposed to mixed PAHs (5, 50, or 500 μg/kg) once every other day during gestation. The adult male offspring displayed impaired glucose tolerance and reduced serum levels of glucagon and insulin. Immunohistochemical staining revealed increased numbers of apoptotic β-cells and a reduced β-cell mass in these males. The downregulated expression of pancreatic estrogen receptor α, androgen receptor, and transcription factor PDX1 was responsible for impacting β-cell development. The relatively reduced α-cell area was associated with downregulated ARX expression. The transcription of Isn2 and Gcg in pancreatic tissue was downregulated, which indicated that the function of β-cells and α-cells was impaired. Methylation levels in the Isn2 promotor were significantly elevated in mice prenatally exposed to 500 µg/kg PAHs, which was consistent with the change in its mRNA levels. The number of macrophages infiltrating islets was significantly increased, indicating that prenatal PAH exposure might reduce islet cell numbers in an autoimmune manner. This study shows that prenatal exposure to PAHs may promote the pathogenesis of type 1 diabetes mellitus.

Relationship between miR-203a inhibition and oil-induced toxicity in early life stage zebrafish (Danio rerio)

Dysregulation of microRNA (miRNA, miR) by environmental stressors influences the transcription of mRNA which may impair organism development and/or lead to adverse physiological outcomes. Early studies evaluating the effects of oil on developmental toxicity in early life stages of fish showed that reductions in expression of miR-203a were associated with enhanced expression of downstream mRNAs that predicted altered eye development, cardiovascular disease, and improper fin development. To better understand the effects of miR-203a inhibition as an outcome of oil-induced toxicity in early life stage (ELS) fish, embryonic zebrafish were injected with an miR-203a inhibitor or treated with 3.5 µM phenanthrene (Phe) as a positive control for morphological alterations of cardiovascular and eye development caused by oil. Embryos treated with Phe had diminished levels of miR-203a at 7 and 72 h after injection. Embryos treated with the miR-203a inhibitor and Phe exhibited a reduced heart rate by 48 h post fertilization (hpf), with an increased incidence of developmental deformities (including pericardial edema, altered eye development, and spinal deformities) and reduced caudal fin length by 72 hpf. There were significant reductions in lens and eye diameters in 120 hpf miR-203a-inhibitor and Phe-treated fish, as well as a significantly reduced number of eye saccades, determined by an optokinetic response (OKR) behavioral assay. The expression of vegfa, which is an important activator during neovascularization, was significantly upregulated in embryos receiving miR-203a inhibitor injections by 7 and 72 hpf with increased trends in vegfa expression in 72 hpf larvae treated with Phe. There were decreasing trends in crx, neurod1, and pde6h expression by 72 hpf in miR-203a inhibitor and Phe treatments, which are involved in photoreceptor function in developing eyes and regulated by miR-203a. These results suggest that an inhibition of miR-203a in ELS fish exhibits an oil-induced toxic response that is consistent with Phe treatment and specifically impacts retinal, cardiac, and fin development in ELS fish.

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miR-203a inhibitor-injected zebrafish exhibited an oil-induced toxic response.

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Inhibition of miR-203a impaired retinal, cardiac, and fin development in zebrafish.

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miR-203a inhibition validated previously predicted transcriptomic pathways.

Insights Into Mechanism of the Naphthalene-Enhanced Biodegradation of Phenanthrene by Pseudomonas sp. SL-6 Based on Omics Analysis

The existence of polycyclic aromatic hydrocarbons (PAHs) in contaminated environment is multifarious. At present, studies of metabolic regulation focus on the degradation process of single PAH. The global metabolic regulatory mechanisms of microorganisms facing coexisting PAHs are poorly understood, which is the major bottleneck for efficient bioremediation of PAHs pollution. Naphthalene (NAP) significantly enhanced the biodegradation of phenanthrene (PHE) by Pseudomonas sp. SL-6. To explore the underlying mechanism, isobaric tags for relative and absolute quantification (iTRAQ) labeled quantitative proteomics was used to characterize the differentially expressed proteins of SL-6 cultured with PHE or NAP + PHE as carbon source. Through joint analysis of proteome and genome, unique proteins were identified and quantified. The up-regulated proteins mainly concentrated in PAH catabolism, Transporters and Electron transfer carriers. In the process, the regulator NahR, activated by salicylate (intermediate of NAP-biodegradation), up-regulates degradation enzymes (NahABCDE and SalABCDEFGH), which enhances the biodegradation of PHE and accumulation of toxic intermediate–1-hydroxy-2-naphthoic acid (1H2Na); 1H2Na stimulates the expression of ABC transporter, which maintains intracellular physiological activity by excreting 1H2Na; the up-regulation of cytochrome C promotes the above process running smoothly. Salicylate works as a trigger that stimulates cell to respond globally. The conjecture was verified at transcriptional and metabolic levels. These new insights contribute to improving the overall understanding of PAHs-biodegradation processes under complex natural conditions, and promoting the application of microbial remediation technology for PAHs pollution.

Environmental pollution and diabetes mellitus

Diabetes mellitus (DM) is a chromic metabolic disease that affects a large segment of the population worldwide. Physical inactivity, poor nutrition, and genetic predisposition are main risk factors for disease development. In the last decade, it was clear to the scientific community that DM development is linked to a novel disease inducer that was later defined as diabetogenic factors of pollution and endocrine disrupting agents. Environmental pollution is exponentially increasing in uncontrolled manner in several countries. Environmental pollutants are of diverse nature and toxicities, including polyaromatic hydrocarbons (PAHs), pesticides, and heavy metals. In the current review, we shed light on the impact of each class of these pollutants and the underlined molecular mechanism of diabetes induction and biological toxicities. Finally, a brief overview about the connection between coronavirus disease 2019 and diabetes pandemics is presented.

Inappropriately sweet: Environmental endocrine-disrupting chemicals and the diabetes pandemic

Afflicting hundreds of millions of individuals globally, diabetes mellitus is a chronic disorder of energy metabolism characterized by hyperglycemia and other metabolic derangements that result in significant individual morbidity and mortality as well as substantial healthcare costs. Importantly, the impact of diabetes in the United States is not uniform across the population; rather, communities of color and those with low income are disproportionately affected. While excessive caloric intake, physical inactivity, and genetic susceptibility are undoubted contributors to diabetes risk, these factors alone fail to fully explain the rapid global rise in diabetes rates. Recently, environmental contaminants acting as endocrine-disrupting chemicals (EDCs) have been implicated in the pathogenesis of diabetes. Indeed, burgeoning data from cell-based, animal, population, and even clinical studies now indicate that a variety of structurally distinct EDCs of both natural and synthetic origin have the capacity to alter insulin secretion and action as well as global glucose homeostasis. This chapter reviews the evidence linking EDCs to diabetes risk across this spectrum of evidence. It is hoped that improving our understanding of the environmental drivers of diabetes development will illuminate novel individual-level and policy interventions to mitigate the impact of this devastating condition on vulnerable communities and the population at large.