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Objective·To explore the effect of double homeobox (DUX) protein on the differentiation potential of mouse embryonic stem cells (mESCs) into extraembryonic endoderm (XEN) and the possible mechanism of its action.Methods·Overexpression of DUX cell lines in mESCs was achieved by using a lentiviral system. The proportion of 2-cell-like cells (2CLCs) before and after DUX overexpression was detected by flow cytometry, and the expression of 2-cell stage-specific genes, Dux, zinc finger and SCAN domain containing 4c (Zscan4c), zinc finger protein 352 (Zfp352) and murine endogenous retrovirus-L polymerase (MERVL-pol), were detected by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR). RT-qPCR assay was used to detect the expression of pluripotency factors, nanog homeobox (Nanog), kruppel-like transcription factor 4 (Klf4), sex determining region Y-box 2 (Sox2), and octamer-binding transcription factor 4 (Oct4), in pluripotent state, as well as the expression of signature genes for different germ layers in the differentiated state [endodermal: GATA binding protein 4 (Gata4), GATA binding protein 6 (Gata6), and sex determining region Y-box 17 (Sox17); ectodermal: Nestin and tubulin beta 3 class Ⅲ (Tubb3); mesodermal: heart and neural crest derivatives expressed 1 (Hand1), myogenic differentiation 1 (Myod1), and kinase insert domain protein receptor (Flk1)]. Public RNA sequencing (RNA-seq) data were mined to further clarify the effect of DUX on the differentiation of mESCs into extraembryonic endoderm. Functional and pathway enrichment analyses of differentially expressed genes were performed using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene set enrichment analysis (GSEA) to identify the signaling pathways regulated by DUX. Additionally, an in-depth analysis of existing chromatin immunoprecipitation sequencing (ChIP-seq) data was conducted to explore the potential target genes of DUX.Results·Molecular biology experiments showed that overexpression of DUX could effectively maintain the pluripotency of mESCs, which was consistent with the analysis of public RNA-seq data. Differential gene analysis revealed that endodermal genes were specifically upregulated. After differentiation assay of mESCs, RT-qPCR assay experiments showed that mRNA expression of the XEN marker genes (Gata4, Gata6, Sox17) was significantly upregulated (P

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Background: Autism spectrum disorder (ASD) is a complex group of neurodevelopmental disorders. Research has highlighted a close association between the retinoic acid (RA) signaling pathway and ASD. This study investigates alterations in the vitamin A (VA, retinol) to RA metabolic pathway in children with ASD and speculates on the underlying reasons for these changes. We propose a subtype characterized by downregulated RA signaling in ASD, laying the groundwork for precise diagnosis and treatment research. Methods: We included 489 children with ASD and 280 typically developing (TD) children. Those with ASD underwent evaluations of core symptoms and neuro-developmental levels, which were conducted by professional developmental behavior physicians using assessment scales. Serum VA and all-trans RA (atRA) levels were determined by high-performance liquid chromatography and ultra-high-performance liquid chromatography–tandem mass spectrometry. The expression levels and concentrations of enzyme molecules such as retinol dehydrogenase 10 were assessed using quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. Results: Children with ASD exhibited reduced serum atRA, accompanied by a downregulation of atRA synthesis enzymes. The reduction in serum atRA levels was linked not only to VA levels but also to the aberrant expression of metabolic enzymes responsible for atRA. Furthermore, the serum atRA levels in children with ASD were more strongly correlated with core symptoms and neurodevelopmental levels than VA levels. Conclusion: Children with ASD exhibited a dual regulation of reduced serum atRA levels, influenced by both VA levels and abnormal expression of atRA metabolic enzymes. [ABSTRACT FROM AUTHOR]

The developmental toxicity and human health risks of triazole fungicides (TFs) have attracted worldwide attention due to the ability to enter the human body in a variety of ways. Nevertheless, the specific mechanism by which TFs exert remains incompletely understood. Given that retinoic acid (RA) signaling pathway are closely related to development, this study aimed to screen and identify developmentally disabled chemicals in commonly used TFs and to reveal the potential effects of TFs on developmental retardation through the RA signaling pathway in mouse embryonic stem cells (mESCs). Specifically, six typical TFs (myclobutanil, tebuconazole, hexaconazole, propiconazole, difenoconazole, and flusilazole) were exposed through the construction of an embryoid bodies (EBs)-based in vitro global differentiation models. Our results clarified that various TFs disturbed lineage commitment during early embryonic development. Crucially, the activation of RA signaling pathway, which alters the expression of key genes and interferes the transport and metabolism of retinol, may be responsible for this effect. Furthermore, molecular docking, molecular dynamics simulations, and experiments using a retinoic acid receptor α inhibitor provide evidence supporting the potential modulatory role of the retinoic acid signaling pathway in developmental injury. The current study offers new insights into the TFs involved in the RA signaling pathway that interfere with the differentiation process of mESCs, which is crucial for understanding the impact of TFs on pregnancy and early development.

Background: The COBLL1 gene has been implicated in human central obesity, fasting insulin levels, type 2 diabetes, and blood lipid profiles. However, its molecular mechanisms remain largely unexplored. Methods: In this study, we established cobll1a mutant lines using the CRISPR/Cas9-mediated gene knockout technique. To further dissect the molecular underpinnings of cobll1a during early development, transcriptome sequencing and bioinformatics analysis was employed. Results: Our study showed that compared to the control, cobll1a-/-zebrafish embryos exhibited impaired development of digestive organs, including the liver, intestine, and pancreas, at 4 days post-fertilization (dpf). Transcriptome sequencing and bioinformatics analysis results showed that in cobll1a knockout group, the expression level of genes in the Retinoic Acid (RA) signaling pathway was affected, and the expression level of lipid metabolismrelated genes (fasn, scd, elovl2, elovl6, dgat1a, srebf1 and srebf2) were significantly changed (p < 0.01), leading to increased lipid synthesis and decreased lipid catabolism. The expression level of apolipoprotein genes (apoa1a, apoa1b, apoa2, apoa4a, apoa4b, and apoea) genes were downregulated. Conclusion: Our study suggest that the loss of cobll1a resulted in disrupted RA metabolism, reduced lipoprotein expression, and abnormal lipid transport, therefore contributing to lipid accumulation and deleterious effects on early liver development. [ABSTRACT FROM AUTHOR]

The evaluation of chemical and pharmaceutical safety for humans is moving from animal studies to New Approach Methodologies (NAM), reducing animal use and focusing on mechanism of action, whilst enhancing human relevance. In developmental toxicology, the mechanistic approach is facilitated by the assessment of predictive biomarkers, which allow mechanistic pathways perturbation monitoring at the basis of human hazard assessment. In our search for biomarkers of maldevelopment, we focused on chemically-induced perturbation of the retinoic acid signaling pathway (RA-SP), a major pathway implicated in a plethora of developmental processes. A genome-wide expression screening was performed on zebrafish embryos treated with two teratogens, all-trans retinoic acid (ATRA) and valproic acid (VPA), and a non-teratogen reference compound, folic acid (FA). Each compound was found to have a specific mRNA expression profile with 248 genes commonly dysregulated by both teratogenic compounds but not by FA. These genes were implicated in several developmental processes (e.g., the circulatory and nervous system). Given the prominent response of neurodevelopmental gene sets, and the crucial need to better understand developmental neurotoxicity, our study then focused on nervous system development. We found 62 genes that are potential early neurodevelopmental toxicity biomarker candidates. These results advance NAM-based safety assessment evaluation by highlighting the usefulness of the RA-SP in providing early toxicity biomarker candidates. • ATRA and VPA both induce perturbation of the retinoic acid signaling pathway. • ATRA and VPA commonly regulate 248 genes not regulated by the negative control FA. • These genes are implicated in diverse developmental processes. • The nervous system development is prominently influenced. • 62 potential neurodevelopmental toxicity gene expression biomarkers were found. [ABSTRACT FROM AUTHOR]

Type 2 diabetes mellitus (T2DM) represents an important microvascular disease concerning the kidney and the brain. Gut dysbiosis and microbiota-derived metabolites may be in relation with early pathophysiological changes in diabetic kidney disease (DKD). The aim of the study was to find new potential gut-derived biomarkers involved in the pathogenesis of early DKD, with a focus on the complex interconnection of these biomarkers with podocyte injury, proximal tubule dysfunction, renal and cerebrovascular endothelial dysfunction. The study design consisted of metabolite profiling of serum and urine of 90 T2DM patients (subgroups P1-normoalbuminuria, P2-microalbuminuria, P3-macroalbuminuria) and 20 healthy controls (group C), based on ultra-high-performance liquid chromatography coupled with electrospray ionization-quadrupole-time of flight-mass spectrometry analysis (UHPLC-QTOF-ESI+-MS). By multivariate and univariate analyses of serum and urine, which included Partial Least Squares Discriminant Analysis (PLSDA), Variable Importance Plots (VIP), Random Forest scores, One Way ANOVA and Biomarker analysis, there were discovered metabolites belonging to nitrogen metabolic pathway and retinoic acid signaling pathway which differentiate P1 group from P2, P3, C groups. Tyrosine, phenylalanine, indoxyl sulfate, serotonin sulfate, and all-trans retinoic acid express the metabolic fingerprint of P1 group vs. P2, P3, C groups, revealing a particular pattern in early DKD in T2DM patients. [ABSTRACT FROM AUTHOR]

BackgroundIn the classical pathway of retinoic acid (RA) mediated gene transcription, RA binds to a nuclear hormone receptor dimer composed of retinoic acid receptor (RAR) and retinoid X receptor (RXR), to induce the expression of its downstream target genes. In addition to nuclear receptors, there are other intracellular RA binding proteins such as cellular retinoic acid binding proteins (CRABP1 and CRABP2) and cytochrome P450 (CYP) enzymes, whose contributions to the RA signaling pathway have not been fully understood. The objective of this study was to compare the significance of various RA binding receptors, i.e. CRABP1, CRABP2, CYP and RAR in the RA signaling pathway. In this regard, we developed a mathematical model of the RA pathway, which is one of the few models, if not the only one, that includes all main intracellular RA binding receptors. We then performed a global sensitivity analysis (GSA) to investigate the contribution of the RA receptors to RA-induced mRNA production, when the cells were treated with a wide range of RA levels, from physiological to pharmacological concentrations.ResultsOur results show that CRABP2 and RAR are the most and the least important proteins, respectively, in controlling the model performance at physiological concentrations of RA (1-10 nM). However, at higher concentrations of RA, CYP and RAR are the most sensitive parameters of the system. Furthermore, we found that depending on the concentrations of all RA binding proteins, the rate of metabolism of RA can either change or remain constant following RA therapy. The cellular levels of CRABP1 are more important than that of CRABP2 in controlling RA metabolite formation at pharmacological conditions (RA = 0.1-1 μM). Finally, our results indicate a significant negative correlation between total mRNA production and total RA metabolite formation at pharmacological levels of RA.ConclusionsOur simulations indicate that the significance of the RA binding proteins in the RA pathway of gene expression strongly depends on intracellular concentration of RA. This study not only can explain why various cell types respond to RA therapy differently, but also can potentially help develop pharmacological methods to increase the efficacy of the drug.

BackgroundProcymidone (PCM) exposure can cause damage to reproductive organs of male mice, but whether its mechanism is related to the retinoic acid (RA) signaling pathway is unclear.ObjectiveTo explore the possible mechanism of PCM-induced testes damage in adolescent mice.MethodsThree-week-old ICR mice (n=64) were randomly divided into a control group and three dose groups (low, medium, and high), with 16 mice in each group. PCM was administered orally at 0, 50, 100, and 200 mg·kg−1·d−1 for 21 consecutive days. Serum and bilateral testes in each mouse were collected to detect content of testosterone in serum and to observe histological changes in testis section after the mice were sacrificed one week after cessation of drug administration. Real-time fluorescence quantitative PCR and Western blotting were used to detect the mRNA expression abundances of genes related to the RA signaling pathway and apoptosis genes Casp9 and Casp12, and the protein expression levels of CYP26A1, ALDH2, and CASP9 respectively.ResultsCompared with the control group, there was no significant change in the overall appearance and testicular appearance of mice in each dose group after the PCM exposure. According to pathological section observation, the testicular seminiferous tubules of mice in the low-dose group showed slight atrophy and reduced sperm production; the testes of mice in the medium- and the high-dose groups showed obvious pathological damage (e.g. dilated lumen of seminiferous tubules, damaged spermatogenic epithelium, decreased number of spermatogonia, and partial absence of sertoli cells); as the concentration of PCM increased, the degree of spermatogenic epithelial damage in mice gradually increased and the number of spermatozoa in the seminiferous tubules decreased. There were no significant differences in the distance between the anus and the genitals, testicular mass, testicular volume, and testicular organ coefficient among the four groups of mice (P>0.05). The body weights of the mice in the low-, medium-, and high-dose groups were (34.91±1.89), (34.88±1.75), and (32.94±1.37) g respectively, and that in the high-dose group was lower than that in the control group, (35.93±1.99) g, (P

The developmental toxicity and human health risks of triazole fungicides (TFs) have attracted worldwide attention due to the ability to enter the human body in a variety of ways. Nevertheless, the specific mechanism by which TFs exert remains incompletely understood. Given that retinoic acid (RA) signaling pathway are closely related to development, this study aimed to screen and identify developmentally disabled chemicals in commonly used TFs and to reveal the potential effects of TFs on developmental retardation through the RA signaling pathway in mouse embryonic stem cells (mESCs). Specifically, six typical TFs (myclobutanil, tebuconazole, hexaconazole, propiconazole, difenoconazole, and flusilazole) were exposed through the construction of an embryoid bodies (EBs)-based in vitro global differentiation models. Our results clarified that various TFs disturbed lineage commitment during early embryonic development. Crucially, the activation of RA signaling pathway, which alters the expression of key genes and interferes the transport and metabolism of retinol, may be responsible for this effect. Furthermore, molecular docking, molecular dynamics simulations, and experiments using a retinoic acid receptor α inhibitor provide evidence supporting the potential modulatory role of the retinoic acid signaling pathway in developmental injury. The current study offers new insights into the TFs involved in the RA signaling pathway that interfere with the differentiation process of mESCs, which is crucial for understanding the impact of TFs on pregnancy and early development. [Display omitted] • Triazole fungicides impact developmental processes based on the EB model. • Triazole fungicides disrupt the transport and metabolism of RA. • Triazole fungicides bind with the RA receptors to induce developmental toxicities. [ABSTRACT FROM AUTHOR]

The etiology of pterygium remains unclear, but ultraviolet (UV) radiation is generally considered to be major risk factor. Pterygium has similarity features with many cancers, including inflammation, invasion, cell proliferation, anti-apoptosis, angiogenesis and recurrence after resection. Retinoic acid via cellular retinoic acid binding protein 2 (CRABP2) is involved in cell cycle arrest, apoptosis and differentiation, while it via fatty acid binding protein 5 (FABP5) is involved in survival, cell proliferation and angiogenesis, which pathway gets activated depends on the CRABP2/FABP5 ratio. Alterations of retinoid signaling were found in many cancer types. The deregulated retinoid signaling may also contribute to the development and/or recurrence of pterygium. The aim of our study was to determine mRNA and protein expressions of CRABP2 and FABP5 and ratio of CRABP2/FABP5 in primer and recurrent pterygium tissues. Pterygia tissues were collected from 30 eyes of 30 patients undergoing pterygium excision. CRABP2 and FABP5 mRNA and protein expression were assessed using Real-time PCR and Western blotting through examination of excised specimens from pterygium and conjunctiva tissues. The ratio of CRABP2/FABP5 gene expression was not altered when primary pterygium tissues compared normal conjunctival tissues (1.00-fold change). Whereas the ratio of CRABP2/ FABP5 gene expression was decreased when recurrent pterygium tissues compared normal conjunctival tissues (0.81-fold change). Understanding etiopathogenesis of pterygium may aid in the find of more promising treatments to prevent pterygium in earlier stages. [ABSTRACT FROM AUTHOR]

Abstract: Scope: We evaluated the potential of retinol and retinoic acid (RA) to enhance intracellular glutathione (GSH) levels in a murine cultured macrophage cell line, RAW264, to investigate whether the RA signaling pathway is involved in the β‐carotene‐induced GSH enhancement. Methods and results: We examined GSH levels in RAW264 cells cultured in media supplemented with β‐carotene and various inhibitors (ER50891 for RA receptor (RAR)α, CD2665 for RARβ/γ, or HX531 for all subtypes of retinoid X receptor (RXR)), to verify each inhibitor's activity against β‐carotene, as well as in media supplemented with various stimulants (AM80 for RARα, CD2314 for RARβ, CD437 for RARγ, or SR11237 for RXR), to compare their activity with that of β‐carotene. We also examined the GSH level and glutamate‐cysteine‐ligase (GCL) expression in RAW264 cells cultured in all‐trans RA‐ or retinol‐supplemented media. Enhanced GSH production was not inhibited by any tested antagonist, and, apart from β‐carotene, no agonist induced GSH production. Retinol, but not all‐trans RA, enhanced GSH synthesis and increased GCL expression, similar to that observed with β‐carotene. Conclusion: The RA signaling pathway may not be involved in the β‐carotene‐induced enhancement of GSH levels in RAW264 cells, whereas, like β‐carotene, retinol can enhance the GSH level and GCL expression. [ABSTRACT FROM AUTHOR]

The zebrafish embryo (ZE) model provides a developmental model well conserved throughout vertebrate embryogenesis, with relevance for early human embryo development. It was employed to search for gene expression biomarkers of compound-induced disruption of mesodermal development. We were particularly interested in the expression of genes related to the retinoic acid signaling pathway (RA-SP), as a major morphogenetic regulating mechanism. We exposed ZE to teratogenic concentrations of valproic acid (VPA) and all-trans retinoic acid (ATRA), using folic acid (FA) as a non-teratogenic control compound shortly after fertilization for 4 h, and performed gene expression analysis by RNA sequencing. We identified 248 genes specifically regulated by both teratogens but not by FA. Further analysis of this gene set revealed 54 GO-terms related to the development of mesodermal tissues, distributed along the paraxial, intermediate, and lateral plate sections of the mesoderm. Gene expression regulation was specific to tissues and was observed for somites, striated muscle, bone, kidney, circulatory system, and blood. Stitch analysis revealed 47 regulated genes related to the RA-SP, which were differentially expressed in the various mesodermal tissues. These genes provide potential molecular biomarkers of mesodermal tissue and organ (mal)formation in the early vertebrate embryo. • ATRA and VPA retinoic acid pathway perturbation alter mesodermal-tissue development. • Transcriptomic changes were found for 7 mesodermal tissues. • 47 potential gene expression maldevelopment biomarkers were found. • 13 were considered potential early biomarkers of general mesodermal maldevelopment. • Some were considered novel potential early biomarkers of specific mesoderm organs. [ABSTRACT FROM AUTHOR]

Objective: To observe the expression of the retinoic acid(RA) pathway in hypothalamus and pituitary damage induced by combined exposure of low-level lead and 1-nitropyrene in mice, and to explore the relationship between the changes of RA pathway and hypothalamus and pituitary damage., Methods: A total of 84 4-week-old ICR mice were randomly divided into the control group, Pb~(2+) tainted group(0.008 mg/L), 1-NP tainted group(0.1 mg/kg), low(0.008 mg/L Pb~(2+)+0.004 mg/kg 1-NP), medium(0.008 mg/L Pb~(2+)+0.02 mg/kg 1-NP), and high-dose co-toxicity group(0.008 mg/L Pb~(2+)+0.1 mg/kg 1-NP) according to body weight, with 14 mice in each group. Among them, Pb~(2+) was provided by lead acetate, added to deionized water and ingested by mice drinking freely, 1-NP was given by intraperitoneal injection, 1-NP was administered by intraperitoneal injection. Record daily water intake and food intake. After 21 consecutive days of exposure, body mass was measured, histological changes in the hypothalamus and pituitary were observed under an optical microscope, and lead content in brain tissue was measured by atomic absorption spectrometry. The real-time fluorescence quantitative PCR was used to detect the abundance of retinoic acid pathway members and c-Jun N-terminal kinases genes(Jnks), and the western blot method was used to detect expression levels of acetaldehyde dehydrogenase 2(ALDH2), cytochrome P450 family member 26A1(CYP26a1) proteins., Results: There was no difference in the mean weekly water intake and food intake of the mice in each group. The body weight of the high-dose co-toxicity group mice((27.4±1.9)g) was lower than that of the control group((29.8±2.3)g)(P&lt;0.05). The level of serum follicle-stimulating hormone(FSH) in the middle and high dose co-toxicity groups((265.01±2.99), (260.42±3.61)pg/mL, respectively) was lower than that in the control group((279.00±1.30)pg/mL, P&lt;0.05). The content of Pb~(2+) in the brain of each group containing Pb~(2+) was higher than that of the control group. In the hypothalamic and pituitary tissues, the abundance of Adh1, Adh2, Rar and Rxr, and ALDH2 levels in the medium and high dose co-toxicity groups were higher than those in the control group(P&lt;0.05). Cyp26a1 gene abundance and protein levels were lower in the medium and high dose co-toxicity groups than in the control group(P&lt;0.05). The abundance of Jnks in the high-dose co-toxicity group was higher than that in the control group(P&lt;0.05)., Conclusion: Continuous exposure to 0.008 mg/L Pb~(2+)+0.1 mg/kg 1-NP for 21 days can cause damage to the hypothalamus and pituitary of mice, and activate the RA signaling pathway.

Objective: To investigate the expression of key genes and proteins of retinoic acid signaling pathway in procymidone-induced uterine injury in adolescent mice, and analyze the relationship between the signaling pathway and female reproductive damage., Methods: The 3-week age ICR mice were randomly divided into low, medium, and high-dose groups and one control group with 8 mice in each group by weight. The low, medium and high dose groups were respectively given 50, 100 and 200 mg/(kg·d) procymidone orally for 21 days continuously, while the control group was given equal volume of soybean oil. After the mice were sacrificed, the uterus was taken from both sides for observing the histological changes in the cross-sectional slices of the uterus, the detection of the expression abundance of genes which related to the retinoic acid signaling pathway by the real-time fluorescent quantitative PCR, and the measurement of ALDH2 and CYP26 a1 proteins expression by Western blot., Results: The body weight of mice in low-dose, medium-dose and high-dose groups were(27.50±1.49) g, (27.72±1.40) g and(26.89±1.19) g, respectively, which were lower than those in control group(31.48±1.14) g(P&lt;0.05). The density of uterine lining monolayer columnar epithelium and lamina propria tubular uterine glands gradually decreases, at the same time the uterine folds become less with the dose of procymidone increases. adh1, ad/2, aldh1a1 in each experimental group were higher than those in the control group(P&lt;0.05); the expression levels of aldh1a2 and aldh1a3 genes in the middle and high dose groups were higher than those in the control group(P&lt;0.05); the expression levels of retinoic acid nuclear receptor rarα, rarγ, rxrα and rxrβ genes in the high-dose group were higher than those in the control(P&lt;0.05); yet the expression levels of cyp26a2 and cyp26a3 in the high-dose group were lower than those in the control group(P&lt;0.05); the jnk family in medium and high dose groups were higher than the control(P&lt;0.05). The expression of ALDH2 in each experimental group was higher than that in the control group, and increased with the increase of the dose(P&lt;0.05); the expression of CYP26 a1 in each experimental group was not significantly different from that of the control group., Conclusion: The retinoic acid signal pathway is activated in procymidone-induced uterine injury in mice, then regulates the increase of the expression of jnk family, leading to the damage.