Perfluorooctanoic acid-induced toxicities in chicken embryo primary cardiomyocytes: Roles of PPAR alpha and Wnt5a/Frizzled2

Persistent metabolic toxicities following developmental exposure to hexafluoropropylene oxide trimer acid (HFPO-TA): Roles of peroxisome proliferator activated receptor gamma

BACKGROUND

Hexafluoropropylene oxide trimer acid (HFPO-TA), a perfluorooctanoic acid (PFOA) substitute, exhibited strong affinity and capability to activate peroxisome proliferator activated receptor gamma (PPARγ), a lipid metabolism regulator, suggesting potential to induce metabolic toxicities.

METHODS

Fertile chicken eggs were exposed to 0, 0.5, 1 or 2 mg/kg (egg weight) HFPO-TA and incubated until hatch. Serum from 0- and 3- month-old chickens were subjected to liquid chromatography ultra-high resolution mass spectrometry for HFPO-TA concentration, while liver, pancreas and adipose tissue samples were collected for histopathological assessments. In ovo PPARγ reporter and silencing system were established with lentivirus microinjection. qRT-PCR and immunohistochemistry were utilized to evaluate the expression levels of PPARγ downstream genes.

RESULTS

In 3-month-old animals developmentally exposed to HFPO-TA, adipose tissue hyperplasia, hepatic steatosis, pancreas islet hypertrophy and elevated serum free fatty acid / insulin levels were observed. Results of reporter assay and qRT-PCR indicated HFPO-TA-mediated PPARγ transactivation in chicken embryo. Silencing of PPARγ alleviated HFPO-TA-induced changes, while PPARγ agonist rosiglitazone mimicked HFPO-TA-induced effects. qRT-PCR and immunohistochemistry revealed that FASN and GPD1 were upregulated following developmental exposure to HFPO-TA in 3-month-old animals.

CONCLUSIONS

Developmental exposure to HFPO-TA induced persistent metabolic toxicities in chickens, in which PPARγ played a central role.

Perfluorooctanoic acid induces cardiac dysfunction in human induced pluripotent stem cell-derived cardiomyocytes

Perfluorooctanoic acid (PFOA), commonly found in drinking water, leads to widespread exposure through skin contact, inhalation, and ingestion, resulting in detectable levels of PFOA in the bloodstream. In this study, we found that exposure to PFOA disrupts cardiac function in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). We observed reductions in field and action potentials in hiPSC-CMs exposed to PFOA. Furthermore, PFOA demonstrated a dose-dependent inhibitory effect on various ion channels, including the calcium, sodium, and potassium channels. Additionally, we noted dose-dependent inhibition of the expression of these ion channels in hiPSC-CMs following exposure to PFOA. These findings suggest that PFOA exposure can impair cardiac ion channel function and decrease the transcription of genes associated with these channels, potentially contributing to cardiac dysfunction such as arrhythmias. Our study sheds light on the electrophysiological and epigenetic consequences of PFOA-induced cardiac dysfunction, underscoring the importance of further research on the cardiovascular effects of perfluorinated compounds (PFCs).

Environmental pollutant pre- and polyfluoroalkyl substances are associated with electrocardiogram parameters disorder in adults

Environmental pollutants exposure might disrupt cardiac function, but evidence about the associations of per- and polyfluoroalkyl substances (PFASs) exposure and cardiac conduction system remains sparse. To explore the associations between serum PFASs exposure and electrocardiogram (ECG) parameters changes in adults, we recruited 1229 participants (mean age: 55.1 years) from communities of Guangzhou, China. 13 serum PFASs with detection rate > 85% were analyzed finally. We selected 6 ECG parameters [heart rate (HR), PR interval, QRS duration, Bazett heart rate-corrected QT interval (QTc), QRS electric axis and RV5 + SV1 voltage] as outcomes. Generalized linear models (GLMs) and Bayesian kernel machine regression (BKMR) model were conducted to explore the associations of individual and joint PFASs exposure and ECG parameters changes, respectively. We detected significant associations of PFASs exposure with decreased HR, QRS duration, but with increased PR interval. For example, at the 95th percentile of 6:2 Cl-PFESA, HR and QRS duration were - 6.98 [95% confidence interval (CI): - 9.07, - 4.90] and - 6.54(95% CI: -9.05, -4.03) lower, but PR interval was 7.35 (95% CI: 3.52, 11.17) longer than those at the 25th percentile. Similarly, significant joint associations were observed in HR, PR interval and QRS duration when analyzed by BKMR model.

A review of cardiovascular effects and underlying mechanisms of legacy and emerging per- and polyfluoroalkyl substances (PFAS)

Cardiovascular disease (CVD) poses the leading threats to human health and life, and their occurrence and severity are associated with exposure to environmental pollutants. Per- and polyfluoroalkyl substances (PFAS), a group of widely used industrial chemicals, are characterized by persistence, long-distance migration, bioaccumulation, and toxicity. Some PFAS, particularly perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexanesulfonic acid (PFHxS), have been banned, leaving only legacy exposure to the environment and human body, while a number of novel PFAS alternatives have emerged and raised concerns, such as polyfluoroalkyl ether sulfonic and carboxylic acid (PFESA and PFECA) and sodium p-perfluorous nonenoxybenzene sulfonate (OBS). Overall, this review systematically elucidated the adverse cardiovascular (CV) effects of legacy and emerging PFAS, emphasized the dose/concentration-dependent, time-dependent, carbon chain length-dependent, sex-specific, and coexposure effects, and discussed the underlying mechanisms and possible prevention and treatment. Extensive epidemiological and laboratory evidence suggests that accumulated serum levels of legacy PFAS possibly contribute to an increased risk of CVD and its subclinical course, such as cardiac toxicity, vascular disorder, hypertension, and dyslipidemia. The underlying biological mechanisms may include oxidative stress, signaling pathway disturbance, lipid metabolism disturbance, and so on. Various emerging alternatives to PFAS also play increasingly prominent toxic roles in CV outcomes that are milder, similar to, or more severe than legacy PFAS. Future research is recommended to conduct more in-depth CV toxicity assessments of legacy and emerging PFAS and explore more effective surveillance, prevention, and treatment strategies, accordingly.

Hexafluoropropylene oxide tetramer acid (HFPO-TeA)-induced developmental toxicities in chicken embryo: Peroxisome proliferator-activated receptor Alpha (PPARα) is involved

Hexafluoropropylene oxide tetramer acid (HFPO-TeA) is an emerging environmental contaminant, with environmental presence but limited toxicological information. To investigate its potential developmental toxicities, various doses of HFPO-TeA exposure were achieved in chicken embryos via air cell injection, and the exposed embryos were incubated until hatch. Within 24 h of hatch, the hatchling chickens were assessed with electrocardiography and histopathology for toxicological evaluation. For mechanistic investigation, in ovo silencing of PPARα was achieved via lentivirus microinjection, then the morphological/functional endpoints along with protein expression levels of PPARα-regulated genes were assessed. HFPO-TeA exposure in chicken embryo resulted in developmental cardiotoxicity and hepatotoxicity. Specifically, decreased right ventricular wall thickness, increased heart rate and hepatic steatosis were observed, whereas silencing of PPARα resulted in alleviation of observed toxicities. Western blotting for EHHADH and FABPs suggested that developmental exposure to HFPO-TeA effectively increased the expression levels of both targets in hatchling chicken heart and liver tissue samples, while PPARα silencing prevented such changes, suggesting that PPARα and its downstream genes are playing critical roles in HFPO-TeA induced developmental toxicities.

Long term toxicities following developmental exposure to perfluorooctanoic acid: Roles of peroxisome proliferation activated receptor alpha

Perfluorooctanoic acid (PFOA) is a widespread persistent organic pollutant. Fertile chicken eggs were exposed to PFOA and incubated to hatch. At three time points post hatch (0-, 1- and 3-months old), chickens were subjected to electrocardiography and sacrificed. Serum was subjected to LC-MS/MS for PFOA concentration, and organs were subjected to histopathological assessments. Additionally, PPARα-silencing lentivirus was co-applied with PFOA exposure, and the corresponding phenotypes were evaluated. Western blotting was performed to assess expressions of FABPs and pSMAD2 in heart and liver samples. Considerable amount of PFOA were detected in hatchling chicken serum, but not in one-month-old or three-month-old chicken serum. PFOA exposure resulted in developmental cardiotoxicity and hepatotoxicity in hatchling chickens. Meanwhile, one-month-old chickens still exhibited elevated heart rate, but classical cardiac remodeling (thicker right ventricular wall) were observed in exposed animals. Three-month-old chickens exhibited similar results as one-month-old ones. PPARα silencing only had partial protective effects in hatchling chickens, but the protective effects seemed to increase as chickens aged. Western blotting results indicated that L-FABP was involved in PFOA-induced hepatotoxicity, while pSMAD2 was involved in PFOA-induced cardiotoxicity. In summary, developmental exposure to PFOA resulted in persistent cardiotoxicity, but not hepatotoxicity. PPARα participates in both cardiotoxicity and hepatotoxicity.

Studying the Impact of Persistent Organic Pollutants Exposure on Human Health by Proteomic Analysis: A Systematic Review

Persistent organic pollutants (POPs) are organic chemical substances that are widely distributed in environments around the globe. POPs accumulate in living organisms and are found at high concentrations in the food chain. Humans are thus continuously exposed to these chemical substances, in which they exert hepatic, reproductive, developmental, behavioral, neurologic, endocrine, cardiovascular, and immunologic adverse health effects. However, considerable information is unknown regarding the mechanism by which POPs exert their adverse effects in humans, as well as the molecular and cellular responses involved. Data are notably lacking concerning the consequences of acute and chronic POP exposure on changes in gene expression, protein profile, and metabolic pathways. We conducted a systematic review to provide a synthesis of knowledge of POPs arising from proteomics-based research. The data source used for this review was PubMed. This study was carried out following the PRISMA guidelines. Of the 742 items originally identified, 89 were considered in the review. This review presents a comprehensive overview of the most recent research and available solutions to explore proteomics datasets to identify new features relevant to human health. Future perspectives in proteomics studies are discussed.

Perfluorooctanoic acid-induced developmental cardiotoxicity in chicken embryo: Roles of miR-490-5p

Perfluorooctanoic acid (PFOA) could induce developmental toxicities, affecting various organs, including the heart. Although peroxisome-proliferation activated receptor alpha (PPARα) had been identified as a major target of PFOA, PPARα-independent effects are frequently reported. To further elucidate the mechanism of toxicity in PFOA-induced developmental cardiotoxicity, RNA-seq analysis was performed in hatchling chicken hearts developmentally exposed to vehicle or 2 mg/kg (egg weight) PFOA. RT-PCR and western blotting were then performed to confirm the identified potential targets. Furthermore, lentivirus was designed to overexpress and silence identified target miRNA in developing chicken embryo, and the resulting phenotypes were investigated. 21 miRNAs and 1142 mRNAs were identified to be affected by developmental exposure to PFOA in chicken embryo hearts. Among the identified differentially expressed miRNAs, miR-490-5p was confirmed to be significantly affected by PFOA exposure, along with its downstream targets, Synaptosome associated protein 91 (SNAP91) and LY6/PLAUR domain containing 6 (LYPD6), as indicated by RT-PCR and western blotting results. Lentivirus overexpressing miR-490-5p mimicked the phenotype induced by PFOA exposure, while lentivirus silencing miR-490-5p alleviated PFOA-induced changes. Similar patterns were also observed in the expression of downstream target genes, SNAP91 and LYPD6. In summary, miR-490-5p and its downstream genes, SNAP91 and LYPD6 are associated with PFOA-induced developmental cardiotoxicity in chicken embryo, which might help to further elucidate the mechanism of PFOA-induced developmental cardiotoxicity.

Profiling biotoxicities of hexafluoropropylene oxide trimer acid with human embryonic stem cell-based assays

Hexafluoropropylene oxide trimer acid (HFPO-TA), an emerging replacement of perfluorooctanoic acid (PFOA), has recently been reported to be a potential environmental contaminant. Due to the similar structure to PFOA, HFPO-TA may cause comparable adverse effects on human health. Therefore, evaluating the toxic profiles of HFPO-TA has become an urgent task. In this study, we investigated the cytotoxicity and hepatoxicity of HFPO-TA using human embryonic stem cell (hESC)-based assays. Results showed that HFPO-TA reduced hESCs' viability in a dose dependent manner, and the calculated IC50 for 24, 48 and 72 hr were 222.8, 167.4, and 80.6 μmol/L, respectively. Significant intracellular ROS accumulation and mitochondrion membrane potential reduction were detected with HFPO-TA exposure, and increased apoptotic/necrotic cells were also observed in high dose of HFPO-TA treated group. Moreover, HFPO-TA at noncytotoxic concentrations also significantly impaired the functions of induced hepatocytes by diminishing cell glycogen storage ability and deregulating specific functional genes. Transcriptome sequencing analysis identified a set of hepatic associated biological processes responding to HFPO-TA exposure. PPAR was the most significantly enriched pathway. Genes including FGA, FGB, FGG, AHSG, HRG, ITIH2, ALB were characterized as hub genes by cytoHubba plug-in. These data indicated that HFPO-TA is a potential hepatotoxicant, and may not be a safe replacement for PFOA.

Angiopoietin-Like 8 in Gestational Diabetes Mellitus: Reduced Levels in Third Trimester Maternal Serum and Placenta, Increased Levels in Cord Blood Serum

Gestational diabetes mellitus (GDM) poses a significant health risk to pregnant women, and thus exploring the potential underlying mechanism is highly desirable. The aim of the study was to compare maternal serum, cord blood serum, and placental angiopoietin-like 8 (ANGPTL8) levels in the third trimester of pregnancy in women with and without gestational diabetes and explore the potential underlying mechanism. A total of 42 pregnant women (23 with GDM and 19 with normal glucose tolerance (NGT)) along with 29 age-matched non-pregnant healthy females were enrolled. All pregnant subjects were in the late third trimester. Maternal serum and cord blood serum ANGPTL8 levels were measured with an enzyme-linked immunosorbent assay and the protein levels of ANGPTL8 in placentas were assessed with western blotting. The associations between maternal serum and cord blood serum ANGPTL8 levels and metabolic parameters were investigated with the Spearman correlation analysis. Significantly lower levels of maternal serum and placental ANGPTL8 levels were observed in GDM patients compared to NGT pregnant women, while remarkably higher ANGPTL8 levels were present in the cord blood serum samples. The maternal serum ANGPTL8 level was positively correlated with BMI, total cholesterol, triglycerides, and AUC for OGTT and birthweight. Additionally, the cord blood serum ANGPTL8 level was positively correlated with insulin and the homeostatic model assessment for insulin resistance. Both maternal serum and cord blood serum ANGPTL8 levels seemed to correlate with GDM and has the potential to be used as a biomarker for GDM and birthweight prediction.

Developmental toxicant exposures and sex-specific effects on epigenetic programming and cardiovascular health across generations

Despite substantial strides in diagnosis and treatment, cardiovascular diseases (CVDs) continue to represent the leading cause of death in the USA and around the world, resulting in significant morbidity and loss of productive years of life. It is increasingly evident that environmental exposures during early development can influence CVD risk across the life course. CVDs exhibit marked sexual dimorphism, but how sex interacts with environmental exposures to affect cardiovascular health is a critical and understudied area of environmental health. Emerging evidence suggests that developmental exposures may have multi- and transgenerational effects on cardiovascular health, with potential sex differences; however, further research in this important area is urgently needed. Lead (Pb), phthalate plasticizers, and perfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants with numerous adverse human health effects. Notably, recent evidence suggests that developmental exposure to each of these toxicants has sex-specific effects on cardiovascular outcomes, but the underlying mechanisms, and their effects on future generations, require further investigation. This review article will highlight the role for the developmental environment in influencing cardiovascular health across generations, with a particular emphasis on sex differences and epigenetic mechanisms. In particular, we will focus on the current evidence for adverse multi and transgenerational effects of developmental exposures to Pb, phthalates, and PFAS and highlight areas where further research is needed.

Hexafluoropropylene oxide dimer acid (HFPO-DA) induced developmental cardiotoxicity and hepatotoxicity in hatchling chickens: Roles of peroxisome proliferator activated receptor alpha

Hexafluoropropylene oxide dimer acid (HFPO-DA) is a perfluorooctanoic acid (PFOA) substitute. In the current study, potential developmental cardiotoxicity and hepatotoxicity following HFPO-DA exposure in chicken embryo has been investigated, focusing on the roles of peroxisome proliferator activated receptor alpha (PPARα), the major molecular target in PFOA-induced toxicities. HFPO-DA was exposed to fertile chicken eggs via air cell injection, morphology and function of the target organs (heart and liver) in hatchlings were investigated with histopathology and electrocardiography, and the serum levels of HFPO-DA had been measured with quadrupole-time of flight liquid chromatograph-mass spectrometer (Q-TOF LC/MS). Additionally, lentivirus-mediated in ovo PPARα silencing was used to assess the roles of PPARα in HFPO-DA induced developmental toxicities. The results indicated that developmental exposure to HFPO-DA induced developmental cardiotoxicity, including thinned right ventricular wall and elevated heart rates, similar to those observed with PFOA exposure, as well as developmental hepatotoxicity in the form of steatosis. Silencing of PPARα alleviated such effects, suggesting participation of PPARα in HFPO-DA induced developmental toxicities in chicken embryo. Moreover, enhanced expression of PPARα downstream genes, cluster of differentiation 36 (CD36) and enoyl-CoA hydratase and 3-hydroxyacyl CoA dehydrogenase (EHHADH), were observed in HFPO-DA exposed animal heart tissues, which can be abolished by PPARα silencing. On the other hand, liver-type fatty acid binding protein (L-FABP) and CD36 expression were effectively enhanced in exposed liver tissues, but not EHHADH, suggesting differential mechanism of toxicity in heart and liver tissues. In summary, developmental exposure to HFPO-DA induced developmental cardiotoxicity and hepatotoxicity in hatchling chickens similar to PFOA, and PPARα still participates in such toxicities, with some differential downstream gene regulations in different organs. Further investigation on HFPO-DA-induced developmental toxicities is guaranteed.

The Combination of Cell Cultured Technology and In Silico Model to Inform the Drug Development

Human-derived in vitro models can provide high-throughput efficacy and toxicity data without a species gap in drug development. Challenges are still encountered regarding the full utilisation of massive data in clinical settings. The lack of translated methods hinders the reliable prediction of clinical outcomes. Therefore, in this study, in silico models were proposed to tackle these obstacles from in vitro to in vivo translation, and the current major cell culture methods were introduced, such as human-induced pluripotent stem cells (hiPSCs), 3D cells, organoids, and microphysiological systems (MPS). Furthermore, the role and applications of several in silico models were summarised, including the physiologically based pharmacokinetic model (PBPK), pharmacokinetic/pharmacodynamic model (PK/PD), quantitative systems pharmacology model (QSP), and virtual clinical trials. These credible translation cases will provide templates for subsequent in vitro to in vivo translation. We believe that synergising high-quality in vitro data with existing models can better guide drug development and clinical use.

Discovery of N-(2-Amino-4-Fluorophenyl)-4-[bis-(2-Chloroethyl)-Amino]-Benzamide as a Potent HDAC3 Inhibitor

In discovery of HDAC inhibitors with improved activity and selectivity, fluorine substitution was performed on our previously derived lead compound. The synthesized molecules N-(2-amino-4-fluorophenyl)-4-[bis-(2-chloroethyl)-amino]-benzamide (FNA) exhibited class I (HDAC1, 2, and 3) selectivity in the in vitro enzymatic assay and especially potent against HDAC3 activity (IC₅₀: 95.48 nM). The results of in vitro antiproliferative assay indicated that FNA exhibited solid tumor cell inhibitory activities with IC₅₀ value of 1.30 μM against HepG2 cells compared with SAHA (17.25 μM). Moreover, the in vivo xenograft model study revealed that FNA could inhibit tumor growth with tumor growth inhibition (TGI) of 48.89% compared with SAHA (TGI of 48.13%). Further HepG2 cell–based apoptosis and cell cycle studies showed that promotion of apoptosis and G2/M phase arrest make contributions to the antitumor activity of FNA. In addition, drug combination results showed that 0.5 μM of FNA could improve the anticancer activity of taxol and camptothecin. The present studies revealed the potential of FNA utilized as a high potent lead compound for further discovery of isoform selective HDAC inhibitors.

In ovo very early-in-life exposure to diesel exhaust induced cardiopulmonary toxicity in a hatchling chick model

Diesel exhaust (DE) had been associated with cardiopulmonary toxicity and developmental toxicity. However, neonatal very early-in-life exposure had not been extensively studied previously. To investigate the potential effects of neonatal very early-in-life exposure to DE, a brand-new chicken embryo in ovo exposure model had been established, with which the cardiopulmonary effects of DE exposure via air cell infusion at embryonic day 18/19 (ED18/19) were assessed in hatchling chicks post-hatch 0-, 1-, or 2-weeks. Heart rates were assessed with electrocardiography. Cardiac and pulmonary morphologies were investigated with histopathological methods. Cardiopulmonary effects were explored with immunohistochemistry for alpha smooth muscle actin (alpha-SMA). In further investigations, the expression levels of phosphorylated AhR, serum levels of TGF-β1, phosphorylated SMAD2/3 and phosphorylated p38MAPK were assessed in the lung tissues. Significantly elevated heart rates, increased right ventricular wall thickness and cardiac collagen deposition were observed in the hearts of exposed hatchling chicks. Significantly increased collagen deposition as well as increased vascular alpha-SMA layer thickness/decreased cavity area were observed in exposed animal lungs. These effects persisted up to two weeks post-hatch. Mechanistic studies revealed elevated phosphorylated AhR expression levels in 0-week and 1-week chicken lungs, while phosphorylated SMAD2/3 levels significantly increased in 0-week chicken lungs but decreased in 2-week chicken lungs following DE exposure. Phosphorylation of p38MAPK did not remarkably increase until 2-week post-hatch. In summary, the novel chicken neonatal very early-in-life exposure model effectively exposed the chicken embryos during the neonatal initial breathing, resulting in cardiopulmonary toxicity, which is associated with AHR, TGF-β1 and MAPK signaling.

L-Carnitine Is Involved in Hyperbaric Oxygen-Mediated Therapeutic Effects in High Fat Diet-Induced Lipid Metabolism Dysfunction

Lipid metabolism dysfunction and obesity are serious health issues to human beings. The current study investigated the effects of hyperbaric oxygen (HBO) against high fat diet (HFD)-induced lipid metabolism dysfunction and the roles of L-carnitine. C57/B6 mice were fed with HFD or normal chew diet, with or without HBO treatment. Histopathological methods were used to assess the adipose tissues, serum free fatty acid (FFA) levels were assessed with enzymatic methods, and the endogenous circulation and skeletal muscle L-carnitine levels were assessed with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Additionally, western blotting was used to assess the expression levels of PPARα, CPT1b, pHSL/HSL, and UCP1. HFD treatment increased body/adipose tissue weight, serum FFA levels, circulation L-carnitines and decreased skeletal muscle L-carnitine levels, while HBO treatment alleviated such changes. Moreover, HFD treatment increased fatty acid deposition in adipose tissues and decreased the expression of HSL, while HBO treatment alleviated such changes. Additionally, HFD treatment decreased the expression levels of PPARα and increased those of CPT1b in skeletal muscle, while HBO treatment effectively reverted such changes as well. In brown adipose tissues, HFD increased the expression of UCP1 and the phosphorylation of HSL, which was abolished by HBO treatment as well. In summary, HBO treatment may alleviate HFD-induced fatty acid metabolism dysfunction in C57/B6 mice, which seems to be associated with circulation and skeletal muscle L-carnitine levels and PPARα expression.