CAR-mediated repression of Cdkn1a(p21) is accompanied by the Akt activation

Constitutive Androstane Receptor Regulates Germ Cell Homeostasis, Sperm Quality, and Male Fertility via Akt-Foxo1 Pathway

Male sexual function can be disrupted by exposure to exogenous compounds that cause testicular physiological alterations. The constitutive androstane receptor (Car) is a receptor for both endobiotics and xenobiotics involved in detoxification. However, its role in male fertility, particularly in regard to the reprotoxic effects of environmental pollutants, remains unclear. This study aims to investigate the role of the Car signaling pathway in male fertility. In vivo, in vitro, and pharmacological approaches are utilized in wild-type and Car-deficient mouse models. The results indicate that Car inhibition impaired male fertility due to altered sperm quality, specifically histone retention, which is correlated with an increased percentage of dying offspring in utero. The data highlighted interactions among Car, Akt, Foxo1, and histone acetylation. This study demonstrates that Car is crucial in germ cell homeostasis and male fertility. Further research on the Car signaling pathway is necessary to reveal unidentified causes of altered fertility and understand the harmful impact of environmental molecules on male fertility and offspring health.

Chronic Aroclor 1260 exposure alters the mouse liver proteome, selenoproteins, and metals in steatotic liver disease

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) continues to increase due in part to the obesity epidemic and to environmental exposures to metabolism disrupting chemicals. A single gavage exposure of male mice to Aroclor 1260 (Ar1260), an environmentally relevant mixture of non-dioxin-like polychlorinated biphenyls (PCBs), resulted in steatohepatitis and altered RNA modifications in selenocysteine tRNA 34 weeks post-exposure. Unbiased approaches identified the liver proteome, selenoproteins, and levels of 25 metals. Ar1260 altered the abundance of 128 proteins. Enrichment analysis of the liver Ar1260 proteome included glutathione metabolism and translation of selenoproteins. Hepatic glutathione peroxidase 4 (GPX4) and Selenoprotein O (SELENOO) were increased and Selenoprotein F (SELENOF), Selenoprotein S (SELENOS), Selenium binding protein 2 (SELENBP2) were decreased with Ar1260 exposure. Increased copper, selenium (Se), and zinc and reduced iron levels were detected. These data demonstrate that Ar1260 exposure alters the (seleno)proteome, Se, and metals in MASLD-associated pathways.

Histone Modification of Colorectal Cancer by Natural Products

Natural products play important roles in the pathogenesis of many human malignancies, including colorectal cancer, and can act as a gene regulator in many cancers. They regulate malignant cell growth through many cellular signal pathways, including Rac family small GTPase 1 (RAC1)/PI3K/AKT (α-serine/threonine-protein kinase), mitogen-activated protein kinase (MAPK), Wnt/β-catenin pathway, transforming growth factor-β (TGF-β), Janus kinase and signal transducer and activator of transcription (JAK-STAT), nuclear factor kappa-B (NF-κB), the Notch pathway, Hippo pathway, and Hedgehog pathway. In this review, we describe the epigenetic roles of several natural products, e.g., platycodin D (PD), ginsenoside Rd, tretinoin, Rutin, curcumin, clove extract, betulinic acid, resveratrol, and curcumin, in colorectal cancer, including their impact on colorectal cancer cell proliferation, apoptosis, invasion, migration, and anti-chemotherapeutic resistance. The aim is to illustrate the epigenetic mechanisms of action of natural products in cancer prevention and treatment, and to provide (1) a theoretical basis for the study of the role of epigenetics in influencing colorectal cancer; (2) new directions for studying the occurrence, development, and prognosis of colorectal cancer; and (3) new targets for treating and preventing colorectal cancer.

Promotion of NR1I3-mediated liver growth is accompanied by STAT3 activation

BACKGROUND

The constitutive androstane receptor (CAR, NR1I3)-mediated mechanisms regulating hepatocyte proliferation and growth of the liver did not yet experience complete elucidation. We investigated whether STAT3 could be activated in vivo by NR1I3 signaling in mouse liver.

METHODS AND RESULTS

Using Western blot analysis, immunofluorescence assays and real-time PCR we established the state of STAT3 activation when it comes to the mouse liver subsequent to treatment ofNR1I3 agonist,1,4-bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP). STAT3 nuclear relocation and hepatocyte growth were both induced by NR1I3-mediated phosphorylation of STAT3. Moreover, the NR1I3-STAT3 signaling pathway's proliferation impact was facilitated, partly, by cMyc and Cyclin D1 upregulation.

CONCLUSIONS

This work's evidence demonstrates that NR1I3-pushed STAT3 activation contributes to TCPOBOP-induced liver growth and hepatocyte proliferation, at least in part, through its molecular targets cMyc and CyclinD1.

Xenobiotic Receptor CAR Is Highly Induced in Psoriasis and Promotes Keratinocyte Proliferation

Psoriasis is a chronic inflammatory skin disease with abnormal epidermal proliferation. Xenobiotics contribute to the pathogenesis of psoriasis. The mechanism linking xenobiotic stimuli with epidermal proliferation remains largely unknown. In this study, we investigated the role of CAR, a nuclear receptor (NR1I3) responsible for xenobiotics detoxification. We showed that CAR and its target genes were induced in the lesions from patients with psoriasis and imiquimod-treated mice. Proinflammatory cytokines (IL-17A, IL-22, oncostatin M, IL-1α, and TNF-α) synergistically increased the expressions of CAR and its target genes in both human and mouse keratinocytes. Overexpression of CAR promoted the G1/S transition by regulating cyclin E and c-Myc expressions, whereas the silencing of CAR attenuated it. Importantly, a selective CAR agonist 6-(4-chlorophenyl)imidazo(2,1-b)(1,3)thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime or the proinflammatory cytokines induced cyclin E and c-Myc, which were largely blocked by clotrimazole, a selective CAR antagonist, or CAR small interfering RNA. In addition, we showed that topical application of 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene, a selective agonist for mouse CAR, exacerbated the IMQ-induced psoriasis lesions with increased expressions of proliferative and inflammatory markers. In contrast, Car-knockout mice developed significantly milder lesions. In conclusion, these results showed that CAR plays a pathogenic role and, potentially, may be a target for the treatment of psoriasis.

Screening and verification of hub genes involved in osteoarthritis using bioinformatics

Osteoarthritis (OA) is one of the most common causes of disability and its development is associated with numerous factors. A major challenge in the treatment of OA is the lack of early diagnosis. In the present study, a bioinformatics method was employed to filter key genes that may be responsible for the pathogenesis of OA. From the Gene Expression Omnibus database, the datasets GSE55457, GSE12021 and GSE55325 were downloaded, which comprised 59 samples. Of these, 30 samples were from patients diagnosed with osteoarthritis and 29 were normal. Differentially expressed genes (DEGs) were obtained by downloading and analyzing the original data using bioinformatics. The Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathways were analyzed using the Database for Annotation, Visualization and Integrated Discovery online database. Protein-protein interaction network analysis was performed using the Search Tool for the Retrieval of Interacting Genes/proteins online database. BSCL2 lipid droplet biogenesis associated, seipin, FOS-like 2, activator protein-1 transcription factor subunit (FOSL2), cyclin-dependent kinase inhibitor 1A (CDKN1A) and kinectin 1 (KTN1) genes were identified as key genes by using Cytoscape software. Functional enrichment revealed that the DEGs were mainly accumulated in the ErbB, MAPK and PI3K-Akt pathways. Reverse transcription-quantitative PCR analysis confirmed a significant reduction in the expression levels of FOSL2, CDKN1A and KTN1 in OA samples. These genes have the potential to become novel diagnostic and therapeutic targets for OA.

Noncanonical Constitutive Androstane Receptor Signaling in Gene Regulation

The constitutive androstane receptor (CAR, NR1I3) is extremely important for the regulation of many physiological processes, especially xenobiotic (drug) metabolism and transporters. CAR differs from steroid hormone receptors in that it can be activated using structurally unrelated chemicals, both through direct ligand-binding and ligand-independent (indirect) mechanisms. By binding to specific responsive elements on DNA, CAR increases the expression of its target genes encoding drug-metabolizing enzymes and transporters. Therefore, CAR is mainly characterized as a ligand-dependent or ligand-independent transcription factor, and the induction of gene expression is considered the canonical mode of CAR action. Consistent with its central role in xenobiotic metabolism, CAR signaling includes a collection of mechanisms that are employed alongside the core transcriptional machinery of the receptor. These so-called noncanonical CAR pathways allow the receptor to coordinate the regulation of many aspects of cell biology. In this mini-review, we review noncanonical CAR signaling, paying special attention to the role of CAR in energy homeostasis and cell proliferation.

Stilbene compound trans-3,4,5,4´-tetramethoxystilbene, a potential anticancer drug, regulates constitutive androstane receptor (Car) target genes, but does not possess proliferative activity in mouse liver

The constitutive androstane receptor(CAR) activation is connected with mitogenic effects leading to liver hyperplasia and tumorigenesis in rodents. CAR activators, including phenobarbital, are considered rodent non-genotoxic carcinogens. Recently, trans-3,4,5,4´-tetramethoxystilbene(TMS), a potential anticancer drug (DMU-212), have been shown to alleviate N-nitrosodiethylamine/phenobarbital-induced liver carcinogenesis. We studied whether TMS inhibits mouse Car to protect from the PB-induced tumorigenesis. Unexpectedly, we identified TMS as a murine CAR agonist in reporter gene experiments, in mouse hepatocytes, and in C57BL/6 mice in vivo. TMS up-regulated Car target genes Cyp2b10, Cyp2c29 and Cyp2c55 mRNAs, but down-regulated expression of genes involved in gluconeogenesis and lipogenesis. TMS did not change or down-regulate genes involved in liver proliferation or apoptosis such as Mki67, Foxm1, Myc, Mcl1, Pcna, Bcl2, or Mdm2, which were up-regulated by another Car ligand TCPOBOP. TMS did not increase liver weight and had no significant effect on Ki67 and Pcna labeling indices in mouse liver in vivo. In murine hepatic AML12 cells, we confirmed a Car-independent proapoptotic effect of TMS. We conclude that TMS is a Car ligand with limited effects on hepatocyte proliferation, likely due to promoting apoptosis in mouse hepatic cells, while controlling Car target genes involved in xenobiotic and endobiotic metabolism.