Regulation Of Nuclear Receptors Research Articles

Molecular basis and dual ligand regulation of tetrameric estrogen receptor α/14-3-3ζ protein complex

Therapeutic strategies targeting nuclear receptors (NRs) beyond their endogenous ligand binding pocket have gained significant scientific interest driven by a need to circumvent problems associated with drug resistance and pharmacological profile. The hub protein 14-3-3 is an endogenous regulator of various NRs, providing a novel entry point for small molecule modulation of NR activity. Exemplified, 14-3-3 binding to the C-terminal F-domain of the estrogen receptor alpha (ERα), and small molecule stabilization of the ERα/14-3-3ζ protein complex by the natural product Fusicoccin A (FC-A), was demonstrated to downregulate ERα-mediated breast cancer proliferation. This presents a novel drug discovery approach to target ERα; however, structural and mechanistic insights into ERα/14-3-3 complex formation are lacking. Here, we provide an in-depth molecular understanding of the ERα/14-3-3ζ complex by isolating 14-3-3ζ in complex with an ERα protein construct comprising its ligand-binding domain (LBD) and phosphorylated F-domain. Bacterial co-expression and co-purification of the ERα/14-3-3ζ complex, followed by extensive biophysical and structural characterization, revealed a tetrameric complex between the ERα homodimer and the 14-3-3ζ homodimer. 14-3-3ζ binding to ERα, and ERα/14-3-3ζ complex stabilization by FC-A, appeared to be orthogonal to ERα endogenous agonist (E2) binding, E2-induced conformational changes, and cofactor recruitment. Similarly, the ERα antagonist 4-hydroxytamoxifen inhibited cofactor recruitment to the ERα LBD while ERα was bound to 14-3-3ζ. Furthermore, stabilization of the ERα/14-3-3ζ protein complex by FC-A was not influenced by the disease-associated and 4-hydroxytamoxifen resistant ERα-Y537S mutant. Together, these molecular and mechanistic insights provide direction for targeting ERα via the ERα/14-3-3 complex as an alternative drug discovery approach.

Perfluorooctanoic acid (PFOA) and hexafluoropropylene oxide-dimer acid (GenX): Hepatic stress and bile acid metabolism with different pathways

Per- and polyfluoroalkyl substances (PFASs) and perfluoroalkyl ether carboxylic acids (PFECAs) are organic chemicals that are widely used in the manufacture of a wide range of human-made products. Many monitoring findings revealed the presence of PFASs and PFECAs in numerous environmental sources, including water, soil, and air, which drew more attention to both chemicals. Because of their unknown toxicity, the discovery of PFASs and PFECAs in a variety of environmental sources was viewed as a cause for concern. In the present study, male mice were given orally one of the typical PFASs, perfluorooctanoic acid (PFOA), and one of the representative PFECAs, hexafluoropropylene oxide-dimer acid (HFPO-DA). The liver index showing hepatomegaly rose significantly after 90 d of exposure to PFOA and HFPO-DA, respectively. While sharing similar suppressor genes, both chemicals demonstrated unique hepatotoxic mechanisms. In different ways, these two substances altered the expression of hepatic stress-sensing genes as well as the regulation of nuclear receptors. Not only are bile acid metabolism-related genes in the liver altered, but cholesterol metabolism-related genes as well. These results indicate that PFOA and HFPO-DA both cause hepatotoxicity and bile acid metabolism impairment with distinct mechanisms.

93 (PB083) - Preclinical Profile of RP14042, a novel, selective, and potent small molecule inhibitor of PARP7

Background: Poly (ADP-ribose) polymerase (PARP)-7 is a member of PARP family and is classified as monoPARP as it catalyzes the transfer of single units of ADP-ribose (MARylation) onto its substrates to exert its physiological functions. It is involved in several cellular processes, including responses to hypoxia, innate immunity, and regulation of nuclear receptors. In addition, PARP7 is overexpressed/amplified in variety of cancers including Ovarian, Breast, Pancreatic ductal adenocarcinoma (PDAC), Non-small cell lung carcinoma (NSCLC) and Squamous cancers. PARP-7 acts as a negative regulator of nucleic acid sensing in tumor cells leading to suppression of Type I interferon (IFN) response. Preclinical studies have demonstrated that inhibition of PARP-7 restores Type I interferon (IFN) signaling leading to tumor cell growth inhibition and activation of the immune system, thereby contributing to tumor regression. Herein, we describe the preclinical profile of RP14042, a novel, selective, and potent small molecule inhibitor of PARP7. Material & Methods: Enzymatic potency was evaluated using a PARP Chemiluminescent Activity Assay Kit (BPS biosciences). Cell growth was determined following incubation with RP14042 as a single agent in various solid tumor cell lines. Cell cycle was evaluated following incubation of cells with compound for 72 h, subsequent staining with Propidium Iodide, and analysis by flow cytometry. Expression of p-STAT1 and p-IRF3 were determined in NCI-H1373 cell line by Western blotting. Pharmacokinetic properties of the molecule were also evaluated. Results: RP14042 inhibited PARP7 with an IC50 of 10.2 nM with selectivity over other members of the PARP family. Compound caused a dose-dependent growth inhibition of NCI-H1373, a PARP-7 overexpressing, cell line with an GI50 of 0.5 μM without any effect on the growth in low PARP-7 expressing cell lines. Incubation of NCI-H1373 cells with RP14042 caused G0/G1 cell cycle arrest. Inhibition of PARP7 by RP14042 in NCI-H1373 induced STAT1 and IRF3 phosphorylation suggesting restoration of Type I IFN signaling. Pharmacokinetic studies in rodents indicated high oral bioavailability with favorable plasma concentrations relevant for efficacy. Conclusion: Data demonstrate the therapeutic potential of RP14042 in PARP7 overexpressing tumors No conflict of interest.

The Effect of Lithocholic Acid on the Gut-Liver Axis.

Lithocholic acid (LCA) is a monohydroxy bile acid produced by intestinal flora, which has been found to be associated with a variety of hepatic and intestinal diseases. LCA is previously considered to be toxic, however, recent studies revealed that LCA and its derivatives may exert anti-inflammatory and anti-tumor effects under certain conditions. LCA goes through enterohepatic circulation along with other bile acids, here, we mainly discuss the effects of LCA on the gut-liver axis, including the regulation of gut microbiota, intestinal barrier, and relevant nuclear receptors (VDR, PXR) and G protein-coupled receptor five in related diseases. In addition, we also find that some natural ingredients are involved in regulating the detoxification and excretion of LCA, and the interaction with LCA also mediates its own biological activity.

Role of cellular retinol-binding protein, type 1 and retinoid homeostasis in the adult mouse heart: A multi-omic approach.

The main active metabolite of Vitamin A, all-trans retinoic acid (RA), is required for proper cellular function and tissue organization. Heart development has a well-defined requirement for RA, but there is limited research on the role of RA in the adult heart. Homeostasis of RA includes regulation of membrane receptors, chaperones, enzymes, and nuclear receptors. Cellular retinol-binding protein, type 1 (CRBP1), encoded by retinol-binding protein, type 1 (Rbp1), regulates RA homeostasis by delivering vitamin A to enzymes for RA synthesis and protecting it from non-specific oxidation. In this work, a multi-omics approach was used to characterize the effect of CRBP1loss using the Rbp1-/- mouse. Retinoid homeostasis was disrupted in Rbp1-/- mouse heart tissue, as seen by a 33% and 24% decrease in RA levels in the left and right ventricles, respectively, compared to wild-type mice (WT). To further inform on the effect of disrupted RA homeostasis, we conducted high-throughput targeted metabolomics. A total of 222metabolite and metabolite combinations were analyzed, with 33having differential abundance between Rbp1-/- and WT hearts. Additionally, we performed global proteome profiling to further characterize the impact of CRBP1loss in adult mouse hearts. More than 2606 unique proteins were identified, with 340 proteins having differential expression between Rbp1-/- and WT hearts. Pathway analysis performed on metabolomic and proteomic data revealed pathways related to cellular metabolism and cardiac metabolism were the most disrupted in Rbp1-/- mice. Together, these studies characterize the effect of CRBP1loss and reduced RA in the adult heart.

Hepatic MIR20B promotes nonalcoholic fatty liver disease by suppressing PPARA.

Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation and imbalances in lipid metabolism in the liver. Although nuclear receptors (NRs) play a crucial role in hepatic lipid metabolism, the underlying mechanisms of NR regulation in NAFLD remain largely unclear. Using network analysis and RNA-seq to determine the correlation between NRs and microRNA in human NAFLD patients, we revealed that MIR20B specifically targets PPARA. MIR20B mimic and anti-MIR20B were administered to human HepG2 and Huh-7 cells and mouse primary hepatocytes as well as high-fat diet (HFD)- or methionine-deficient diet (MCD)-fed mice to verify the specific function of MIR20B in NAFLD. We tested the inhibition of the therapeutic effect of a PPARα agonist, fenofibrate, by Mir20b and the synergic effect of combination of fenofibrate with anti-Mir20b in NAFLD mouse model. We revealed that MIR20B specifically targets PPARA through miRNA regulatory network analysis of nuclear receptor genes in NAFLD. The expression of MIR20B was upregulated in free fatty acid (FA)-treated hepatocytes and the livers of both obesity-induced mice and NAFLD patients. Overexpression of MIR20B significantly increased hepatic lipid accumulation and triglyceride levels. Furthermore, MIR20B significantly reduced FA oxidation and mitochondrial biogenesis by targeting PPARA. In Mir20b-introduced mice, the effect of fenofibrate to ameliorate hepatic steatosis was significantly suppressed. Finally, inhibition of Mir20b significantly increased FA oxidation and uptake, resulting in improved insulin sensitivity and a decrease in NAFLD progression. Moreover, combination of fenofibrate and anti-Mir20b exhibited the synergic effect on improvement of NAFLD in MCD-fed mice. Taken together, our results demonstrate that the novel MIR20B targets PPARA, plays a significant role in hepatic lipid metabolism, and present an opportunity for the development of novel therapeutics for NAFLD. This research was funded by Korea Mouse Phenotyping Project (2016M3A9D5A01952411), the National Research Foundation of Korea (NRF) grant funded by the Korea government (2020R1F1A1061267, 2018R1A5A1024340, NRF-2021R1I1A2041463, 2020R1I1A1A01074940, 2016M3C9A394589324), and the Future-leading Project Research Fund (1.210034.01) of UNIST.

Identification of the RORα Transcriptional Network Contributes to the Search for Therapeutic Targets in Atherosclerosis.

The retinoic acid receptor-related orphan receptor α (RORα) is involved in the regulation of several physiological processes, including development, metabolism, and circadian rhythm. RORα-deficient mice display profound atherosclerosis, in which hypoalphalipoproteinemia is reportedly associated with decreased plasma levels of high-density lipoprotein, increased levels of inflammatory cytokines, and ischemia/reperfusion-induced damage. The recent characterization of endogenous ligands (including cholesterol, oxysterols, provitamin D3, and their derivatives), mediators, and initiation complexes associated with the transcriptional regulation of these orphan nuclear receptors has facilitated the development of synthetic ligands. These findings have also highlighted the potential of application of RORα as a therapeutic target for several diseases, including diabetes, dyslipidemia, and atherosclerosis. In this review, the current literature related to the structure and function of RORα, its genetic inter-individual differences, and its potential as a therapeutic target in atherosclerosis is discussed.

Exosome-Derived MicroRNAs of Human Milk and Their Effects on Infant Health and Development

Multiple biologically active components of human milk support infant growth, health and development. Milk provides a wide spectrum of mammary epithelial cell-derived extracellular vesicles (MEVs) for the infant. Although the whole spectrum of MEVs appears to be of functional importance for the growing infant, the majority of recent studies report on the MEV subfraction of milk exosomes (MEX) and their miRNA cargo, which are in the focus of this review. MEX and the dominant miRNA-148a play a key role in intestinal maturation, barrier function and suppression of nuclear factor-κB (NF-κB) signaling and may thus be helpful for the prevention and treatment of necrotizing enterocolitis. MEX and their miRNAs reach the systemic circulation and may impact epigenetic programming of various organs including the liver, thymus, brain, pancreatic islets, beige, brown and white adipose tissue as well as bones. Translational evidence indicates that MEX and their miRNAs control the expression of global cellular regulators such as DNA methyltransferase 1—which is important for the up-regulation of developmental genes including insulin, insulin-like growth factor-1, α-synuclein and forkhead box P3—and receptor-interacting protein 140, which is important for the regulation of multiple nuclear receptors. MEX-derived miRNA-148a and miRNA-30b may stimulate the expression of uncoupling protein 1, the key inducer of thermogenesis converting white into beige/brown adipose tissue. MEX have to be considered as signalosomes derived from the maternal lactation genome emitted to promote growth, maturation, immunological and metabolic programming of the offspring. Deeper insights into milk’s molecular biology allow the conclusion that infants are both “breast-fed” and “breast-programmed”. In this regard, MEX miRNA-deficient artificial formula is not an adequate substitute for breastfeeding, the birthright of all mammals.

Nuclear receptor regulation of transcription by phosphoinositides: PIP3 acyl chains control the structure and function of SF‐1.

Nuclear receptor regulation of transcription by phosphoinositides: PIP3 acyl chains control the structure and function of SF‐1.

PARP7 and Mono-ADP-Ribosylation Negatively Regulate Estrogen Receptor α Signaling in Human Breast Cancer Cells

ADP-ribosylation is a post-translational protein modification catalyzed by a family of proteins known as poly-ADP-ribose polymerases. PARP7 (TIPARP; ARTD14) is a mono-ADP-ribosyltransferase involved in several cellular processes, including responses to hypoxia, innate immunity and regulation of nuclear receptors. Since previous studies suggested that PARP7 was regulated by 17β-estradiol, we investigated whether PARP7 regulates estrogen receptor α signaling. We confirmed the 17β-estradiol-dependent increases of PARP7 mRNA and protein levels in MCF-7 cells, and observed recruitment of estrogen receptor α to the promoter of PARP7. Overexpression of PARP7 decreased ligand-dependent estrogen receptor α signaling, while treatment of PARP7 knockout MCF-7 cells with 17β-estradiol resulted in increased expression of and recruitment to estrogen receptor α target genes, in addition to increased proliferation. Co-immunoprecipitation assays revealed that PARP7 mono-ADP-ribosylated estrogen receptor α, and mass spectrometry mapped the modified peptides to the receptor’s ligand-independent transactivation domain. Co-immunoprecipitation with truncated estrogen receptor α variants identified that the hinge region of the receptor is required for PARP7-dependent mono-ADP-ribosylation. These results imply that PARP7-mediated mono-ADP-ribosylation may play an important role in estrogen receptor positive breast cancer.

The Long Noncoding RNA Hepatocyte Nuclear Factor 4α Antisense RNA 1 Negatively Regulates Cytochrome P450 Enzymes in Huh7 Cells via Histone Modifications.

The maintenance of homeostasis of cytochromes P450 enzymes (P450s) under both physiologic and xenobiotic exposure conditions is ensured by the action of positive and negative regulators. In the current study, the hepatocyte nuclear factor 4α (HNF4A) antisense RNA 1 (HNF4A-AS1), an antisense long noncoding RNA of HNF4A, was found to be a negative regulator of the basal and rifampicin (RIF)-induced expression of nuclear receptors and downstream P450s. In Huh7 cells, knockdown of HNF4A-AS1 resulted in elevated expression of HNF4A, pregnane X receptor (PXR), and P450s (including CYP3A4) under both basal and RIF-induced conditions. Conversely, overexpression of HNF4A-AS1 led to decreased basal expression of constitutive androstane receptor, aryl hydrocarbon receptor, PXR, and all studied P450s. Of note, significantly diminished induction levels of PXR and CYP1A2, 2C8, 2C19, and 3A4 by RIF were also observed in HNF4A-AS1 plasmid-transfected Huh7 cells. Moreover, the negative feedback of HNF4A on HNF4A-AS1-mediated gene expression was validated using a loss-of-function experiment in this study. Strikingly, our data showed that increased enrichment levels of histone 3 lysine 4 trimethylation and HNF4A in the CYP3A4 promoter contribute to the elevated CYP3A4 expression after HNF4A-AS1 knockdown. Overall, the current study reveals that histone modifications contribute to the negative regulation of nuclear receptors and P450s by HNF4A-AS1 in basal and drug-induced levels. SIGNIFICANCE STATEMENT: Utilizing loss-of-function and gain-of-function experiments, the current study systematically investigated the negative regulation of HNF4A-AS1 on the expression of nuclear receptors (including HNF4A, constitutive androstane receptor, aryl hydrocarbon receptor, and pregnane X receptor) and P450s (including CYP1A2, 2E1, 2B6, 2D6, 2C8, 2C9, 2C19, and 3A4) in both basal and rifampicin-induced levels in Huh7 cells. Notably, this study is the first to reveal the contribution of histone modification to the HNF4A-AS1-mediated expression of CYP3A4 in Huh7 cells.

Hormone receptor 4 is required in muscles and distinct ovarian cell types to regulate specific steps of Drosophila oogenesis.

The conserved nuclear receptor superfamily has crucial roles in many processes, including reproduction. Nuclear receptors with known roles in oogenesis have been studied mostly in the context of their ovary-intrinsic requirement. Recent studies in Drosophila, however, have begun to reveal new roles of nuclear receptor signaling in peripheral tissues in controlling reproduction. Here, we identified Hormone receptor 4 (Hr4) as an oogenesis regulator required in the ovary and muscles. Global Hr4 knockdown leads to increased germline stem cell (GSC) loss, reduced GSC proliferation, early germline cyst death, slowed follicle growth and vitellogenic follicle degeneration. Tissue-specific knockdown experiments uncovered ovary-intrinsic and peripheral tissue requirements for Hr4 In the ovary, Hr4 is required in the niche for GSC proliferation and in the germline for GSC maintenance. Hr4 functions in muscles to promote GSC maintenance and follicle growth. The specific tissues that require Hr4 for survival of early germline cysts and vitellogenic follicles remain unidentified. These results add to the few examples of muscles controlling gametogenesis and expand our understanding of the complexity of nuclear receptor regulation of various aspects of oogenesis.

Inhibition effect of epigallocatechin-3-gallate on the pharmacokinetics of calcineurin inhibitors, tacrolimus, and cyclosporine A, in rats

ABSTRACT Background Epigallocatechin-3-gallate (EGCG) is the most biologically active catechin of green tea. Tacrolimus (TAC) and cyclosporine A (CsA) are immunosuppressive agents commonly used in clinical organ transplantation. The present study investigated the effect of EGCG on the pharmacokinetics of TAC and CsA in rats and its underlying mechanisms. Research design and methods Either TAC or CsA was administered to rats intravenously or orally with or without concomitant EGCG. Polymerase Chain Reaction and Western Blot were used to determine the effect of EGCG on drug-metabolizing enzymes (DMEs), drug transporters (DTs) and nuclear receptors (NRs). Results The Cmax and AUC of TAC were reduced, and V/F and CL/F of TAC were enhanced after co-administration of EGCG. EGCG increased the Cmax, AUC of CsA at 3 ~ 30 mg∙kg-1 dosages, while decreased those parameters at the dosage of 100 mg∙kg-1. EGCG inhibited the mRNA and protein expressions of DMEs and DTs, such as CYP3A1, A2, UGT1A1, Mdr1 and Mrp2, but upregulated the expressions of Car, Pxr and Fxr. Conclusions These results revealed consumption of high dose EGCG may cause a significant alteration in pharmacokinetics of TAC and distribution/elimination profiles of CsA through the regulation of DMEs, DTs and NRs.

Abstract 6061: NR2F1 limits dissemination of early cancer mammary epithelial cells

Abstract Cancer cells have been found to disseminate during very early and sometimes asymptomatic stages of tumor progression. At secondary organs, early disseminated cancer cells (eDCCs) can enter a non-proliferative state for prolonged periods of time. Intriguingly, eDCCs also carry metastasis- initiating capacity. However, the mechanisms by which these early cancer cells complete all steps of metastasis including metastasis-initiating capacity are unknown. Here we report that the orphan nuclear receptor and lineage commitment regulator NR2F1 serves as an early barrier to early dissemination propelled by HER2 signaling. NR2F1 loss of function in HER2 early cancer cells induced cell motility, loss of E-cadherin junctions, disorganized laminin-V deposition, decreased β-catenin membrane localization and increased micro-invading cells with CK14+/CK18 phenotype. Importantly, upon NR2F1 depletion in HER2 early cancer acini, TWIST, ZEB1 and PRRX1 levels were upregulated. Our findings reveal a previously unrecognized function of NR2F1 as a suppressor of dissemination during early stages of breast tumor progression. Thus, therapies that restore and activate NR2F1 function might limit early dissemination and metastatic outgrowth. Citation Format: Maria Soledad Sosa, Nupura Kale, Nitisha Shrivastava, Carolina Rodriguez-Tirado, Maria Carlini, Jiayi Ji, Javier Bravo-Cordero. NR2F1 limits dissemination of early cancer mammary epithelial cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6061.

Research progress in application and mechanism of Schisandrae Chinensis Fructus for prevention and treatment of liver diseases

Schisandra is the mature fruit of Schisandra chinensis(known as "north Schisandra") or S. shenanthera(known as "south Schisandra"). S. chinensis contains a variety of lignans, volatile oils, polysaccharides, organic acids and other chemical constituents; among them, lignans are recognized as the characteristic active components. Clinical studies have found that Schisandra and Schisandra-related products have a better effect in the prevention and treatment of viral hepatitis, drug-induced liver injury, liver cirrhosis, liver failure and other liver diseases. Modern pharmacological studies have demonstrated that Schisandra has a variety of pharmacological activities, such as anti-inflammation, antioxidation, anticancer, regulation of nuclear receptor, antivirus, regulation of cytochrome P450 enzyme, inhibition of liver cell apoptosis and promotion of liver regeneration. This paper reviews the studies about the applications and mechanism of Schisandra in the prevention and treatment of liver diseases, in the expectation of providing guidance for the development of hepatoprotective drugs from Schisandra and the clinical applications of Schisandra-related products.

Regulation of the germinal center response by nuclear receptors and implications for autoimmune diseases.

The immune system plays an essential role in protecting the host from infectious diseases and cancer. Notably, B and T lymphocytes from the adaptive arm of the immune system can co‐operate to form long‐lived antibody responses and are therefore the main target in vaccination approaches. Nevertheless, protective immune responses must be tightly regulated to avoid hyper‐responsiveness and responses against self that can result in autoimmunity. Nuclear receptors (NRs) are perfectly adapted to rapidly alter transcriptional cellular responses to altered environmental settings. Their functional role is associated with both immune deficiencies and autoimmunity. Despite extensive linking of nuclear receptor function with specific CD4 T helper subsets, research on the functional roles and mechanisms of specific NRs in CD4 follicular T helper cells (Tfh) and germinal center (GC) B cells during the germinal center reaction is just emerging. We review recent advances in our understanding of NR regulation in specific cell types of the GC response and discuss their implications for autoimmune diseases such as systemic lupus erythematosus (SLE).

Histone 3 Lysine 9 Methylating Enzyme G9a Regulates Transcriptional Expression of Nuclear Receptors and Cytochrome P450 Genes in HepaRG Cells

Histone modification transcriptionally regulate gene expression. Cytochrome P450 genes are studied extensively in terms of regulation of expression through histone modification. Histone 3 lysine 4 (H3K4) and Histone 3 lysine 27 (H3K27) methylation are studied extensively in regulation of P450 gene expression. Another histone modification Histone 3 lysine 9 methylation, is well known for transcriptional repression of genes but not studies well in regulation of nuclear receptors and cytochrome P450 gene expression. In this study, the role of histone methyl transferase G9a, which is responsible for mono and di‐methylation of histone 3 lysine 9 residue, was studied in regulation of drug metabolizing enzymes and nuclear receptors. We treated HepaRG cell with small interfering RNA to selectively knockdown EHMT2 mRNA and using adenovirus, G9a was overexpressed to study the effect on nuclear receptors CAR (NR1I3), PXR (NR1I2), AHR and heterodimer partner RXRα along with the selected drug metabolizing cytochrome P450 genes. In pathological conditions such as steatosis, the expression of nuclear receptors and cytochrome P450 genes is affected along with G9a in a mice model treated with high fat diet. In this study, we treated HepaRG cells with fatty acids to induce steatosis. In conclusion we observed that loss of G9a shown to decrease mRNA expression of nuclear receptors and cytochrome P450 genes whereas overexpression of G9a increased expression of nuclear receptors CAR (NR1I3), PXR (NR1I2)and selected drug metabolizing enzymes CYP1A2, CYP2B6, CYP2C9, CYP3A4 etc. In fatty acid treated cells overexpression of G9a was observed to prevent fatty acid mediated down regulation of nuclear receptor CAR (NR1I3) and drug metabolizing enzyme genes CYP2C19, CYP2C8 and CYP3A4.Support or Funding InformationThis project work was funded by Boehringer Ingelheim Pharmaceuticals

Exploring the Mechanism of Action Compound-Xueshuantong Capsule in Diabetic Retinopathy Treatment Based on Network Pharmacology.

Materials and Methods The components with oral bioavailability ≥30% and drug similarity ≥0.18 were screened by the Traditional Chinese Medicine System Pharmacology Database and Analysis Platform (TCMSP), and the effective grouping of Compound-Xueshuantong Capsule was obtained. At the same time, the targets of each drug active component in the Compound-Xueshuantong Capsule were obtained by searching the TCMSP. The effective components and targets of the Compound-Xueshuantong Capsule were annotated by the UniProt database, and the disease treatment targets were searched by the GeneCards database. The disease treatment target is intersected with the drug target and the Wayne diagram is drawn by VennDiagram. The active ingredient targets of the intersection and Compound-Xueshuantong Capsule were inputted into Cytoscape 3.7.2 software to construct the active ingredient-target-disease interaction network. The above targets were inputted into the String database for protein-protein interaction network prediction. Finally, by using the DAVID database, GO and KEGG enrichment analysis was carried out to reveal the potential signal pathway of the Compound-Xueshuantong Capsule in diabetic retinopathy treatment. Results 93 active components of the Compound-Xueshuantong Capsule and 92 targets for treating diabetic retinopathy were screened. The main active components of the Compound-Xueshuantong Capsule in treating diabetic retinopathy were quercetin, luteolin, kaempferol, beta-sitosterol, isorhamnetin, and tanshinone IIa. The effect of the Compound-Xueshuantong Capsule on diabetic retinopathy may be related to IL6, EFGR, CASP3, and VEGFA. In addition, the treatment of diabetic retinopathy mainly involves in the regulation of nuclear receptors and transcription factors in vivo. The target of the Compound-Xueshuantong Capsule in diabetic retinopathy treatment is significantly enriched in the AGE-RAGE signal pathway, TNF signal pathway, HIF-1 signal pathway, and VEGF signal pathway in diabetic complications. Conclusion Compound-Xueshuantong Capsule can treat diabetic retinopathy through multitarget, multipathway, and multipathway regulation of the biomolecular network. The potential biological mechanism of the Compound-Xueshuantong Capsule in diabetic retinopathy treatment may be related to the AGE-RAGE signal pathway, TNF signal pathway, HIF-1 signal pathway, and VEGF signal pathway in diabetic complications, but these findings still need to be confirmed by further clinical research.

IDPs and their complexes in GPCR and nuclear receptor signaling.

G protein-coupled receptors (GPCRs) and Nuclear Receptors (NRs) are two signaling machineries that are involved in major physiological processes and, as a consequence, in a substantial number of diseases. Therefore, they actually represent two major targets for drugs with potential applications in almost all public health issues. Full exploitation of these targets for therapeutic purposes nevertheless requires opening original avenues in drug design, and this in turn implies a better understanding of the molecular mechanisms underlying their functioning. However, full comprehension of how these complex systems function and how they are deregulated in a physiopathological context is obscured by the fact that these proteins include a substantial number of disordered regions that are central to their mechanism of action but whose structural and functional properties are still largely unexplored. In this chapter, we describe how these intrinsically disordered regions (IDR) or proteins (IDP) intervene, control and finely modulate the thermodynamics of complexes involved in GPCR and NR regulation, which in turn triggers a multitude of cascade of events that are exquisitely orchestrated to ultimately control the biological output.

Disruption of hepatic small heterodimer partner induces dissociation of steatosis and inflammation in experimental nonalcoholic steatohepatitis

Disruption of hepatic small heterodimer partner induces dissociation of steatosis and inflammation in experimental nonalcoholic steatohepatitis