Effect of PPARβ/δ Agonist on the Placentation and Embryo-Fetal Development in Rats

Predicting Prenatal Developmental Toxicity Based On the Combination of Chemical Structures and Biological Data

For hazard identification, classification, and labeling purposes, animal testing guidelines are required by law to evaluate the developmental toxicity potential of new and existing chemical products. However, guideline developmental toxicity studies are costly, time-consuming, and require many laboratory animals. Computational modeling has emerged as a promising, animal-sparing, and cost-effective method for evaluating the developmental toxicity potential of chemicals, such as endocrine disruptors, without the use of animals. We aimed to develop a predictive and explainable computational model for developmental toxicants. To this end, a comprehensive dataset of 1244 chemicals with developmental toxicity classifications was curated from public repositories and literature sources. Data from 2140 toxicological high-throughput screening assays were extracted from PubChem and the ToxCast program for this dataset and combined with information about 834 chemical fragments to group assays based on their chemical-mechanistic relationships. This effort revealed two assay clusters containing 83 and 76 assays, respectively, with high positive predictive rates for developmental toxicants identified with animal testing guidelines (PPV = 72.4 and 77.3% during cross-validation). These two assay clusters can be used as developmental toxicity models and were applied to predict new chemicals for external validation. This study provides a new strategy for constructing alternative chemical developmental toxicity evaluations that can be replicated for other toxicity modeling studies.

Modeling Trophoblast Cell-Guided Uterine Spiral Artery Transformation in the Rat

The rat possesses hemochorial placentation with deep intrauterine trophoblast cell invasion and trophoblast-guided uterine spiral artery remodeling, which resembles human placentation. Uterine spiral arteries are extensively remodeled to deliver sufficient supply of maternal blood and nutrients to the developing fetus. Inadequacies in these key processes negatively impact fetal growth and development. Recent innovations in genome editing combined with effective phenotyping strategies have provided new insights into placental development. Application of these research approaches has highlighted both conserved and species-specific features of hemochorial placentation. The review provides foundational information on rat hemochorial placental development and function during physiological and pathological states, especially as related to the invasive trophoblast cell-guided transformation of uterine spiral arteries. Our goal is to showcase the utility of the rat as a model for in vivo mechanistic investigations targeting regulatory events within the uterine-placental interface.

Metabolic study of GW1516 in equine urine using liquid chromatography/electrospray ionization Q-Exactive high-resolution mass spectrometry for doping control

RATIONALE

The use of GW1516, a peroxisome proliferator-activated receptor δ (PPAR δ) agonist, is strictly prohibited in both horseracing and equestrian competitions. However, little is known about its metabolic fate in horses. To the best of our knowledge, this is the first reported metabolic study of GW1516 in equine urine.

METHODS

Urine samples obtained from a thoroughbred after nasoesophageal administration with GW1516 were protein-precipitated and the supernatants were subsequently analyzed by liquid chromatography/electrospray ionization high-resolution mass spectrometry (LC/ESI-HRMS) with a Q-Exactive mass spectrometer. Monoisotopic ions of GW1516 and its metabolites were monitored from the full-scan mass spectral data of pre- and post-administration samples. A quantification method was developed and validated to establish the excretion profiles of GW1516, its sulfoxide, and its sulfone in equine urine.

RESULTS

GW1516 and its nine metabolites [including GW1516 sulfoxide, GW1516 sulfone, 5-(hydroxymethyl)-4-methyl-2-(4-trifluoromethylphenyl)thiazole (HMTT), methyl 4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazole-5-carboxylate (MMTC), 4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazole-5-carboxylic acid (MTTC), and M1 to M4] were detected in post-administration urine samples. GW1516 sulfoxide and GW1516 sulfone showed the longest detection times in post-administration urine samples and were therefore recommended as potential screening targets for doping control purposes. Quantitative analysis was also conducted to establish the excretion profiles of GW1516 sulfoxide and GW1516 sulfone in urine.

CONCLUSIONS

For the purposes of doping control of GW1516, the GW1516 sulfoxide and GW1516 sulfone metabolites are recommended as the target analytes to be monitored in equine urine due to their high specificities, long detection times (1 and 4 weeks, respectively), and the ready availability of their reference materials.

Peroxisome Proliferator-Activated Receptors (PPAR), fatty acids and microRNAs: Implications in women delivering low birth weight babies

Low birth weight (LBW) babies are associated with neonatal morbidity and mortality and are at increased risk for noncommunicable diseases (NCDs) in later life. However, the molecular determinants of LBW are not well understood. Placental insufficiency/dysfunction is the most frequent etiology for fetal growth restriction resulting in LBW and placental epigenetic processes are suggested to be important regulators of pregnancy outcome. Early life exposures like altered maternal nutrition may have long-lasting effects on the health of the offspring via epigenetic mechanisms like DNA methylation and microRNA (miRNA) regulation. miRNAs have been recognized as major regulators of gene expression and are known to play an important role in placental development. Angiogenesis in the placenta is known to be regulated by transcription factor peroxisome proliferator-activated receptor (PPAR) which is activated by ligands such as long-chain-polyunsaturated fatty acids (LCPUFA). In vitro studies in different cell types indicate that fatty acids can influence epigenetic mechanisms like miRNA regulation. We hypothesize that maternal fatty acid status may influence the miRNA regulation of PPAR genes in the placenta in women delivering LBW babies. This review provides an overview of miRNAs and their regulation of PPAR gene in the placenta of women delivering LBW babies.Abbreviations: AA - Arachidonic Acid; Ago2 - Argonaute2; ALA - Alpha-Linolenic Acid; ANGPTL4 - Angiopoietin-Like Protein 4; C14MC - Chromosome 14 miRNA Cluster; C19MC - Chromosome 19 miRNA Cluster; CLA - Conjugated Linoleic Acid; CSE - Cystathionine γ-Lyase; DHA - Docosahexaenoic Acid; EFA - Essential Fatty Acids; E2F3 - E2F transcription factor 3; EPA - Eicosapentaenoic Acid; FGFR1 - Fibroblast Growth Factor Receptor 1; GDM - Gestational Diabetes Mellitus; hADMSCs - Human Adipose Tissue-Derived Mesenchymal Stem Cells; hBMSCs - Human Bone Marrow Mesenchymal Stem Cells; HBV - Hepatitis B Virus; HCC - Hepatocellular Carcinoma; HCPT - Hydroxycamptothecin; HFD - High-Fat Diet; Hmads - Human Multipotent Adipose-Derived Stem; HSCS - Human Hepatic Stellate Cells; IUGR - Intrauterine Growth Restriction; LA - Linoleic Acid; LBW - Low Birth Weight; LCPUFA - Long-Chain Polyunsaturated Fatty Acids; MEK1 - Mitogen-Activated Protein Kinase 1; MiRNA - MicroRNA; mTOR - Mammalian Target of Rapamycin; NCDs - NonCommunicable Diseases; OA - Oleic Acid; PASMC - Pulmonary Artery Smooth Muscle Cell; PLAG1 - Pleiomorphic Adenoma Gene 1; PPAR - Peroxisome Proliferator-Activated Receptor; PPARα - PPAR alpha; PPARγ - PPAR gamma; PPARδ - PPAR delta; pre-miRNA - precursor miRNA; RISC - RNA-Induced Silencing Complex; ROS - Reactive Oxygen Species; SAT - Subcutaneous Adipose Tissue; WHO - World Health Organization.

Revisiting preeclampsia: a metabolic disorder of the placenta

Preeclampsia (PE) is a leading cause of maternal and neonatal mortality and morbidity worldwide, impacting the long-term health of both mother and offspring. PE has long been characterized by deficient trophoblast invasion into the uterus and consequent placental hypoperfusion, yet the upstream causative factors and effective interventional targets for PE remain unknown. Alterations in the metabolism of preeclamptic placentas are thought to result from placental ischemia, while disturbances of the metabolism and of metabolites in PE pathogenesis are largely ignored. In fact, as one of the largest fetal organs at birth, the placenta consumes a considerable amount of glucose and fatty acid. Increasing evidence suggests glucose and fatty acid exist as energy substrates and regulate placental development through bioactive derivates. Moreover, recent findings have revealed that the placental metabolism adapts readily to environmental changes, altering its response to nutrients and endocrine signals; this adaptability optimizes pregnancy outcomes by diversifying available carbon sources for energy production, hormone synthesis, angiogenesis, immune activation, and tolerance, and fetoplacental growth. These observations raise the possibility that carbohydrate and lipid metabolism abnormalities play a role in both the etiology and clinical progression of PE, sparking a renewed interest in the interrelationship between PE and metabolic dysregulation. This review will focus on key metabolic substrates and regulatory molecules in the placenta and aim to provide novel insights with respect to the metabolism's role in modulating placental development and functions. Further investigations from this perspective are poised to decipher the etiology of PE and suggest potential therapies.

Perfluoroalkyl Substances (PFAS) and Their Effects on the Placenta, Pregnancy, and Child Development: a Potential Mechanistic Role for Placental Peroxisome Proliferator-Activated Receptors (PPARs)

PURPOSE OF REVIEW

This review summarizes studies highlighting perfluoroalkyl substances (PFAS) and their effects on the placenta, pregnancy outcomes, and child health. It highlights human population-based associations as well as in vitro-based experimental data to inform an understanding of the molecular mechanisms underlying these health effects. Among the mechanisms by which PFAS may induce toxicity is via their interaction with the peroxisome proliferator-activated receptors (PPARs), nuclear receptors that regulate lipid metabolism and placental functions important to healthy pregnancies, as well as fetal and child development.

RECENT FINDINGS

In utero exposure to prevalent environmental contaminants such as PFAS is associated with negative health outcomes during pregnancy, birth outcomes, and later in life. Specifically, PFAS have been associated with increased incidence of gestational diabetes, childhood obesity, preeclampsia, and fetal growth restriction. In terms of placental molecular mechanisms underlying these associations, studies demonstrate that PFAS interfere with trophoblast lipid homeostasis, inflammation, and invasion. Moreover these effects could be mediated in part by the interaction between PFAS and PPARs, as well as other biological mechanisms. This review summarizes how PFAS, critical environmental contaminants, may contribute to diseases of pregnancy as well as early and later child health.

Doping control analysis of GW1516 in equine plasma using liquid chromatography/electrospray ionization Q-Exactive high-resolution mass spectrometry

RATIONALE

GW1516 is a peroxisome proliferator-activated receptor-δ agonist in the class of hormones and metabolic modulators. The use of GW1516 is banned in both horseracing and equestrian competitions. To the best of our knowledge, this is the first metabolic study of GW1516 in horses.

METHODS

After protein precipitation of pre- and post-administration plasma GW1516 samples, the supernatants were analyzed using liquid chromatography/electrospray ionization Q-Exactive high-resolution mass spectrometry to detect GW1516 and its metabolites. Monoisotopic ions of GW1516 and its metabolites were monitored from the full-scan mass spectral data of pre- and post-administration samples. Quantification methods were developed and validated to establish the elimination profiles of GW1516, its sulfoxide, and its sulfone in equine plasma.

RESULTS

GW1516 and its four metabolites GW1516 sulfoxide, GW1516 sulfone, 5-(hydroxymethyl)-4-methyl-2-(4-trifluoromethylphenyl)thiazole (HMTT), and M1 were detected in post-administration plasma samples. GW1516 sulfoxide, GW1516 sulfone, and HMTT were identified by comparison with their respective reference standards whereas M1 was tentatively identified as 4-methyl-2-[4-(trifluoromethyl)phenyl]-1,3-thiazole-5-carboxylic acid by mass spectral interpretation. GW1516 had the longest detection time in post-administration plasma. The elimination profiles of GW1516, its sulfoxide, and its sulfone in plasma were established.

CONCLUSIONS

For the purpose of doping control, GW1516 is recommended as the target analyte to be monitored in equine plasma due to its long detection time (around 1 week) and the ready availability of its reference material.

PPARs and Angiogenesis-Implications in Pathology

Peroxisome proliferator-activated receptors (PPARs) belong to the family of ligand-activated nuclear receptors. The PPAR family consists of three subtypes encoded by three separate genes: PPARα (NR1C1), PPARβ/δ (NR1C2), and PPARγ (NR1C3). PPARs are critical regulators of metabolism and exhibit tissue and cell type-specific expression patterns and functions. Specific PPAR ligands have been proposed as potential therapies for a variety of diseases such as metabolic syndrome, cancer, neurogenerative disorders, diabetes, cardiovascular diseases, endometriosis, and retinopathies. In this review, we focus on the knowledge of PPAR function in angiogenesis, a complex process that plays important roles in numerous pathological conditions for which therapeutic use of PPAR modulation has been suggested.

Thiazolidinedione drugs in the treatment of type 2 diabetes mellitus: past, present and future

Thiazolidinedione (TZD) drugs used in the treatment of type 2 diabetes mellitus (T2DM) have proven effective in improving insulin sensitivity, hyperglycemia, and lipid metabolism. Though well tolerated by some patients, their mechanism of action as ligands of peroxisome proliferator-activated receptors (PPARs) results in the activation of several pathways in addition to those responsible for glycemic control and lipid homeostasis. These pathways, which include those related to inflammation, bone formation, and cell proliferation, may lead to adverse health outcomes. As treatment with TZDs has been associated with adverse hepatic, cardiovascular, osteological, and carcinogenic events in some studies, the role of TZDs in the treatment of T2DM continues to be debated. At the same time, new therapeutic roles for TZDs are being investigated, with new forms and isoforms currently in the pre-clinical phase for use in the prevention and treatment of some cancers, inflammatory diseases, and other conditions. The aims of this review are to provide an overview of the mechanism(s) of action of TZDs, a review of their safety for use in the treatment of T2DM, and a perspective on their current and future therapeutic roles.

Effect of Xianziyizhen Recipe Capsule on PGI2-PPARδ Signaling Pathway in Embryo Implantation Dysfunction Mice

PROBLEM

We investigated the effect of Xianziyizhen recipe capsule (XRC), a kidney-tonifying herb, on the PGI2-PPARδ signaling pathway at the maternal-fetal interface in embryo implantation dysfunction (EID) mice.

METHOD OF STUDY

Intragastric administration of Progynova (estradiol) or XRC was performed in EID mouse model, following experimental induction of kidney deficiency by co-treatment with chemotherapy drug hydroxyurea and antiprogesterone mifepristone. The PPARδ and IL-11 mRNA expression in endometrium were detected by real-time relative reverse transcription-polymerase chain reaction (RT-PCR). Further, the protein expression of COX-2, PGI2, MMP-9, and TIMP-3 was detected in endometrial glandular epithelium and in stromal cells by immunohistochemical (IHC) assay.

RESULTS

The results showed that hydroxyurea and mifepristone-induced EID were associated with significantly lower PPARδ and IL-11 mRNA levels in endometrium and reduced COX-2, PGI2, MMP-9, and TIMP-3 levels in endometrial glandular epithelium, compared with normal controls. However, XRC and Progynova treatment reversed these effects, leading to significant increases in PPARδ and IL-11 mRNA expression, and COX-2, PGI2, MMP-9 and TIMP-3 protein levels, when compared with the levels observed in EID mice.

CONCLUSION

These results strongly suggested that XRC is beneficial in EID treatment and that XRC may mediate its effects through regulation of the PGI2-PPARδ signaling pathway.

Effect of chlorpromazine on rat placenta development

We examined the sequential histopathological changes in the placentas from rats exposed to chlorpromazine. Chlorpromazine was intraperitoneally administered on GD 14 at 50 and 100 mg/kg and the placentas were sampled on GDs 14.5, 15, 17 and 21. The incidence of dams with complete fetal resorption was increased from GD 17 up to 20% at 50 mg/kg and 44.4% at 100 mg/kg. The embryo/fetal weights reduced on GDs 15 and 17 at 50 mg/kg and during GDs 15-21 at 100 mg/kg. The placental weights reduced on GD 17 at 50 mg/kg and during GDs 14.5-21 at 100 mg/kg. Histopathologically, in the labyrinth zone, apoptotic cells were scattered in the trophoblastic septa without inhibition of cell proliferation on GDs 14.5 and 15 at 50 and 100 mg/kg in a dose-dependent manner. A decrease in trophoblasts led to labyrinth zone hypoplasia. In the basal zone, apoptotic cells were scattered on GDs 14.5 and 15 at 100 mg/kg, and most of them appeared to be glycogen cells. A decrease in glycogen cells induced the delayed development of glycogen cell islands and the subsequent remaining glycogen cell islands, and led to the cystic degeneration of glycogen cells. In addition, failure of development of the glycogen cell islands led to the impaired interstitial invasion of the glycogen cells, and then metrial gland hypoplasia occurred.