Member Of Nuclear Receptor Superfamily Research Articles

Structurally Distinct Nurr1 Ligands Exhibit Different Pharmacological Characteristics in Regulating Inflammatory Responses of Microglial BV-2 Cells.

Nurr1 (NR4A2) is a member of nuclear receptor superfamily that regulates gene transcription in midbrain dopaminergic neurons and also inhibits nuclear factor-κB-mediated inflammatory responses in brain microglial cells. To date, various compounds have been reported to stimulate transcriptional activity of Nurr1 on neuronal genes, but their anti-inflammatory actions are poorly characterized. The present study examined the effects of three kinds of Nurr1 ligands, amodiaquine, 1,1-bis(3'-indolyl)-1-(p-chlorophenyl)-methane (C-DIM12) and 5-chloronaphthalen-1-amine (5-CNA), on inflammatory responses of microglial BV-2 cells. Lipopolysaccharide (LPS)-induced upregulation of interleukin-1β mRNA and tumor necrosis factor α mRNA was inhibited by all three compounds, whereas upregulation of interleukin-6 mRNA and inducible nitric oxide synthase (iNOS) mRNA was significantly inhibited only by 5-CNA. On the other hand, LPS-induced nuclear translocation of p65 subunit of nuclear factor-κB was prevented only by amodiaquine. C-DIM12 increased nuclear localization of Nurr1 and transiently upregulated Nurr1 protein expression, whereas amodiaquine and 5-CNA had no effect on these parameters. Notably, inhibitory effect of 5-CNA on iNOS mRNA upregulation was reversed by co-application of amodiaquine. Conversely, inhibitory effect of amodiaquine on p65 nuclear translocation was cancelled by 5-CNA. These results reveal distinct characteristics of anti-inflammatory actions of Nurr1 ligands.

Study of Estrogen Receptor Gene Thymine-Adenine Repeat Polymorphisms in Low Birth Weight and Premature Infants with Bone Disease

Abstract Introduction Metabolic Bone disease (MBD) of prematurity is a disorder of bone health with hypocalcemia, hypo or hyperphosphatemia and radiological findings of bone demineralization. MBD often presents in newborns <28wks of gestation in 16-40% of VLBW and ELBW (Rustico et al., 2014). Several pathophysiological conditions have been suggested as factors behind MBD including inadequate supply of calcium and phosphorus. as well as side effects of some drugs as corticosteroids (Lothe et al., 2011 & Sharma and Sohi, 2012). Genetic predisposition to low bone mass content (BMC) in premature infants have been studied lately (Saraff et al., 2021). Estrogen Receptor (ER), a group of nuclear receptor superfamily members has been recently implicated in the development of osteoporosis suggesting the use of its gene as a possible candidate gene for bone mineral density (BMD) (Gennari et al. 2005). The targeted deletion of ER in mice has affected the periosteum (Clancy et al., 2017). Having several polymorphic sites for ER, the low number of Thymine adenine repeats (Ho-L) was found to relate with increased fracture risk or BMD in certain populations (Rooney et al., 2017). Aim of the Work Studying the relation between allelic polymorphism of Thymine Adenine repeats variant of ER gene and metabolic bone disease in low birth weight and premature infants. Patients and Methods A case-controlled study conducted at NICU Ain Shams University Hospitals starting from February 2022 till February 2023. Inclusion criteria: Cases (25): VLBW premature infants with bone disease evidenced by laboratory data (low calcium, low phosphorous and high alkaine phosphatase. (Hung et al., 2011) serving as group 1. Controls (25): VLBW premature infants without bone disease evidenced by normal laboratory data, serving as group 2. Exclusion criteria: Full term infants, or premature infants with syndromic features suggesting genetic diseases or chromosomal anomalies. Parents of patients signed an informed consent before being enrolled to this study and after approval of Ethical committee Ain Shams University. All patients and controls were subjected to the following: Full history taking and examination with special emphasis on length, weight and their SDS, gestational age. Laboratory sample for measurement of ALP, Calcium, phosphorous. Genomic DNA was extracted then amplified by PCR to study TA repeats of ER using gene jet purification mini kit (Kany et al., 2019). Results Group 1 had a percent of females and males of 58 and 48% respectively. their birth weight SD ranged from -6.8 to -3.86 while length SD ranged from -2.8 to -3.6. According to laboratory parameters; there was statistically significant decrease in the level of Ca (8.41 ± 0.86) and Phosphorus (1.96 ± 0.43)and increase in alkaline phosphatase (935.60 ± 50.83) among group 1 compared to group 2. Genotyping of TA repeats of ER, Ho-L(homo with low T-A repeated sequences <19), He-LH(hetero with low and high T-A repeated sequences <19 and>18) were statistically significantly higher in Group 1, while Ho-H(homo with high T-A repeated sequences >18) was significantly higher among group 2. There was a statistically significant increase of Ho-L in males more than females. Also gestational age, birth weight and birth length were less in Ho-L group. Percentage of infants on mechanical ventilation was higher among those with Ho-L group. Conclusion This study concluded that premature infants with less TA repeats of ER gene showed higher incidence of MBD, suggesting the possible link between TA repeats of ER gene with the development of MBD.

Decoration of GW9662 scaffold with a fragment-like hit via copper-catalyzed azide-alkyne cycloaddition reaction into peroxisome proliferator-activated receptor γ agonists

PPARγ is a member of nuclear receptor superfamily, which possesses a large Y-shaped cavity in the ligand-binding pocket. GW9662 is a well-known PPARγ antagonist which covalently reacts with the Cys285 residue via nucleophilic substitution. In contrast to its irreversibility, the ability of GW9662 to prevent other ligands from accessing the ligand-binding pocket is partly defective. By focusing on this incompleteness, we develop an integrated approach to create a new PPARγ agonist by using a structure of GW9662 as a scaffold for linking with a fragment compound. A screening of 1,040 compounds identified a partner ligand which synergistically activates PPARγ transcription in combination with GW9662. We introduced an azido or alkyne group to GW9662 or the identified fragment hit, respectively, and then connected the two structures via copper-catalyzed azide-alkyne cycloaddition. A coupling reaction provided a series of hybrid structure with triazole linker, among which the compounds with a bent configuration function as a partial PPARγ agonist. These results highlight a potential utility of GW9662 for the decoration with a fragment compound to develop a covalent agonist for PPARγ activation.

Deciphering the role of classical oestrogen receptor in insulin resistance and type 2 diabetes mellitus: From molecular mechanism to clinical evidence

The biological actions of oestrogen are mediated by the oestrogen receptor α or β (ERα or ERβ), which are members of a broad nuclear receptor superfamily. Numerous in vivo and in vitro studies have demonstrated that loss of circulating oestrogen modulated by classical ERα and ERβ led to rapid changes in pancreatic β-cell and islet function, GLUT4 expression, insulin sensitivity and glucose tolerance, dysfunctional lipid homeostasis, oxidative stress, and inflammatory cascades. Remarkably, 17β-oestradiol (E2) can completely reverse these effects. This review evaluates the current understanding of the protective role of classical ER in critical pathways and molecular mechanisms associated with insulin resistance and type 2 diabetes mellitus (T2DM). It also examines the effectiveness of menopausal hormone therapy (MHT) in reducing the risk of developing T2DM in menopausal women. Clinical trials have shown the protective effects of MHT on glucose metabolism, which may be useful to treat T2DM in perimenopausal women. However, there are concerns about E2's potential side effects of obesity and hyperlipidaemia in menopausal women. Further studies are warranted to gain understanding and find other oestrogen alternatives for treatment of insulin resistance and T2DM in postmenopausal women.

Targeting Peroxisome Proliferator-Activated Receptor-β/δ, Reactive Oxygen Species and Redox Signaling with Phytocompounds for Cancer Therapy.

Significance: Peroxisome proliferator-activated receptors (PPARs) have a moderately preserved amino-terminal domain, an extremely preserved DNA-binding domain, an integral hinge region, and a distinct ligand-binding domain that are frequently encountered with the other nuclear receptors. PPAR-β/δ is among the three nuclear receptor superfamily members in the PPAR group. Recent Advances: Emerging studies provide an insight on natural compounds that have gained increasing attention as potential anticancer agents due to their ability to target multiple pathways involved in cancer development and progression. Critical Issues: Modulation of PPAR-β/δ activity has been suggested as a potential therapeutic strategy for cancer management. This review focuses on the ability of bioactive phytocompounds to impact reactive oxygen species (ROS) and redox signaling by targeting PPAR-β/δ for cancer therapy. The rise of ROS in cancer cells may play an important part in the initiation and progression of cancer. However, excessive levels of ROS stress can also be toxic to the cells and cancer cells with increased oxidative stress are likely to be more vulnerable to damage by further ROS insults induced by exogenous agents, such as phytocompounds and therapeutic agents. Therefore, redox modulation is a way to selectively kill cancer cells without causing significant toxicity to normal cells. However, use of antioxidants together with cancer drugs may risk the effect of treatment as both act through opposite mechanisms. Future Directions: It is advisable to employ more thorough and detailed methodologies to undertake mechanistic explorations of numerous phytocompounds. Moreover, conducting additional clinical studies is recommended to establish optimal dosages, efficacy, and the impact of different phytochemicals on PPAR-β/δ.

Serum adiponectin and peroxisome proliferator-activated receptors-γ levels in obese patients with and without prediabetes.

Obesity is an increasingly prevalent global health problem, which is generally caused by the increase in body fat mass above normal and observed in all societies. If the blood glucose level is higher than normal but not high enough to diagnose diabetes, this condition is defined as prediabetes. Adiponectin increases fatty acid oxidation and insulin sensitivity and is closely associated with obesity. One of the nuclear receptor superfamily member peroxisome proliferator-activated receptors is shown to have an important role in various metabolic reactions. This study aimed to investigate the serum levels of adiponectin and peroxisome proliferator-activated receptors-gamma parameters, which are closely related to adipose tissue, energy metabolism, and insulin sensitivity, in obese patients with and without prediabetes. For this purpose, 52 obese patients with prediabetes, 48 obese patients with non-prediabetes, and 76 healthy individuals were included in this study. Serum adiponectin and peroxisome proliferator-activated receptors-γ levels were analyzed by ELISA. Serum adiponectin levels were significantly higher in obese patients with prediabetes (18.15±15.99) compared with the control group (15.17±15.67; p=0.42). No significant difference was observed in both adiponectin and peroxisome proliferator-activated receptors-γ levels in the obese patients with the non-prediabetes group compared with the control group. However, no significant difference was observed in the obese patients with prediabetes group and obese patients with non-prediabetes group. Our results suggest that adiponectin may serve as an indicator of prediabetes. This implies that examining adiponectin levels in individuals diagnosed with prediabetes may enhance our understanding of the metabolic processes closely linked to prediabetes and related conditions.

Dietary regulation of peroxisome proliferator-activated receptors in metabolic syndrome

BackgroundPeroxisome proliferator-activated receptors (PPARs) are a class of ligand-activated nuclear transcription factors, members of the type nuclear receptor superfamily, with three subtypes, namely PPARα, PPARβ/δ, and PPARγ, which play a key role in the metabolic syndrome. In the past decades, a large number of studies have shown that natural products can act by regulating metabolic pathways mediated by PPARs. PurposeThis work summarizes the physiological importance and clinical significance of PPARs and reviews the experimental evidence that natural products mediate metabolic syndrome via PPARs. MethodsThis study reviews relevant literature on clinical trials, epidemiology, animals, and cell cultures published in NCBI PubMed, Scopus, Web of Science, Google Scholar, and other databases from 2001 to October 2022. Search keywords were "natural product" OR "botanical" OR "phytochemical" AND "PPAR" as well as free text words. ResultsThe modulatory involvement of PPARs in the metabolic syndrome has been supported by prior research. It has been observed that many natural products can treat metabolic syndrome by altering PPARs. The majority of currently described natural compounds are mild PPAR-selective agonists with therapeutic effects that are equivalent to synthetic medicines but less harmful adverse effects. ConclusionPPAR agonists can be combined with natural products to treat and prevent metabolic syndrome. Further human investigations are required because it is unknown how natural products cause harm and how they might have negative impacts.

Fenofibrate Attenuates Radiation-Induced Oxidative Damage to the Skin through Fatty Acid Binding Protein 4 (FABP4).

Radiation facilities and radioactive materials have been widely used in military, industry, medicine, science and nuclear facilities, which has significantly increased the potential of large-scale, uncontrolled exposure to radiation. The skin is one of the radiosensitive organ systems and radiation-induced skin injury remains a serious concern after ionizing radiation exposure. Our previous report indicates the involvement of the peroxisome proliferator-activated receptor pathway in the response of skin tissues to ionizing radiation. PPARα is a member of the PPAR nuclear hormone receptor superfamily, which can be activated by fibrate ligands. However, the protection of fenofibrate against ionizing radiation in skin keratinocytes and fibroblasts has not been described. The PPARα mRNA levels in irradiated and nonirradiated skin tissues of rats were determined by real-time assay. The expression of PPARα, and FABP4 were evaluated by western blot and IHC assay. The cell proliferation was detected by colony formation. The γH2AX foci and ROS levels in irradiated WS1 cells with FABP4 overexpression than in control cells were performed by Immunofluorescence assay. We found that PPARα expression was lower in the irradiated skin tissues of mouse, rat, monkey, and human patients than in their nonirradiated counterparts. PPARα fenofibrate significantly decreased radiation-induced ROS and apoptosis in a dose-dependent manner in human keratinocyte HaCaT and skin fibroblast WS1 cells. Moreover, fenofibrate significantly decreased radiation-induced ROS and malondialdehyde (MDA) levels in electron beam irradiated skin tissues of rats. Mechanistically, the proximal promoter of fatty acid binding protein 4 (FABP4) harbored three binding sites of PPARα and fenofibrate stimulated the transcription of FABP4 in skin cells. FABP4 overexpression decreased radiation-induced ROS and γH2AX foci. FABP4 inhibitor BMS309403 abrogated the ROS-eliminating activity as well as the lipid-accumulating role of fenofibrate, indicating that FABP4 mediates the radioprotective role of fenofibrate. In addition, FABP4 overexpression significantly decreased radiation-induced oxidative damage in vivo. These results confirm that fenofibrate attenuated radiation-induced oxidative damage to the skin by stimulating FABP4.

Fenofibrate mediated activation of PPARα negatively regulates trophoblast invasion

The Peroxisome Proliferator-Activated Receptor-alpha (PPARα) is a member of the ligand-dependent nuclear receptor superfamily known for their crucial role in lipid metabolism. The expression and role of PPARα in trophoblast cells are not very well known. Trophoblast invasion is one of the most critical processes required for successful implantation of the developing embryo into the maternal endometrium. Defects in this process are associated with adverse pregnancy outcomes such as FGR(Fetal Growth Restriction), Preeclampsia, and choriocarcinoma. In this present study, we investigated the role of the ligand-activated transcription factor, Peroxisome proliferator-activated receptor (PPARα) in regulating trophoblast cell invasion using cell lines and explants-based models. Immunohistological localization of PPARα in human placental tissues showed a gestational variation with relatively low expression at term as compared to early trimester. PCR and Western Blot also confirmed this. Further to delineate the effect of PPAR alpha on trophoblast invasion, EVT derived HTR8/SVneo cell lines were stimulated with PPARα agonist, i.e., fenofibrate (FF). Fenofibrate stimulation led to an increased activation and nuclear translocation of PPARα, followed by reduced migration and invasion of these cells in a matrigel invasion assay (Boyden chamber). PPAR alpha stimulation also led to a reduced MMP-2/9 expression following our previous observation. Thus, we may conclude that PPARα to be playing a very important regulatory role in orchestrating the invasive trophoblast programme and hence it seems plausible for it to be associated with PE, which is often characterized by a shallow trophoblast invasion.

Retinoid receptors are expressed in mouse and human lungs.

Retinoid receptors are members of nuclear receptor superfamily consisting of two distinct families: RARs (retinoic acid receptors) and RXRs (retinoid X receptors). Each family contains three receptor subtypes α, β, and γ. Retinoids transduce their effects through binding to retinoid receptors and inhibit transcription factors such as activator protein-1 and nuclear factor-κB (NF-κB) both of which regulate the transcription of several inflammatory genes. Considering the role of retinoid receptors in lung physiology, we need a precise understanding of their expression in normal and inflamed lungs. We used light and electron microscopic immunohistochemistry and Western blot to determine the expression of retinoid receptors in a murine model of endotoxin-induced (E. coli; 055:B5, 80 μg intranasal) acute lung inflammation and normal human lungs. Western blot showed expression of all six retinoid receptor subtypes in normal and inflamed mouse lungs. Immunohistology localized differential expression of retinoid receptors in airway epithelium, alveolar/septal macrophages, vascular endothelium, and alveolar septum in mouse lungs. Intranasal LPS challenge in mice resulted in increased expression of RXRα in airway epithelium compared to control animals. All six retinoid receptor subtypes were expressed in normal human lungs. Immunoelectron microscopy further confirmed the localization of all the receptors in various lung cells including the nucleus of these cells. The basal and altered expression of retinoid receptors in normal and inflamed lungs, respectively, may suggest their roles in lung pathophysiology.

Insulin‐mimetic action of bile acids via FXR

Farnesoid X receptor (FXR), a member of the orphan nuclear receptor superfamily, plays roles in diverse metabolic pathways including bile acids, lipids, glucose, and lipoproteins. We tested a signal transduction of FXR that integrated into the phosphoinositide 3-kinase (PI3K) pathway. In HepG2 cells and Caco-2 cells, FXR in the presence of GW4064 (synthetic FXR agonist) and CDCA (chenodeoxycholic acid, physiological FXR agonist) enhanced signals in PI3K that led to increase in glucose (GLC) uptake and glycogen synthase (GS) activity. Effects of FXR on GLC and GS were effectively reversed by LY200094. However, these positive effects were not observed in the presence of natural FXR antagonists such as LCA (lithocholic acid) and guggulsterone. We also confirmed that effects of FXR were comparable to those of insulin. In addition, FXR was coprecipitated in the presence of GW4064, but not insulin. We conclude that CDCA and GW4064 produce the insulin-mimetic action via FXR in the glucose metabolism in these cells.

Quantitative Immunohistochemistry to Measure Regional Expression of Nurr1 in the Brain and the Effect of the Nurr1 Heterozygous Genotype.

The transcription factor Nurr1 is a member of the steroid hormone nuclear receptor superfamily. Ablation of Nurr1 expression arrests mesencephalic dopamine neuron differentiation while attenuation of Nurr1 in the subiculum and hippocampus impairs learning and memory. Additionally, reduced Nurr1 expression has been reported in patients with Parkinson’s disease and Alzheimer’s disease. In order to better understand the overall function of Nurr1 in the brain, quantitative immunohistochemistry was used to measure cellular Nurr1 protein expression, across Nurr1 immunoreactive neuronal populations. Additionally, neuronal Nurr1 expression levels were compared between different brain regions in wild-type mice (+/+) and Nurr1 heterozygous mice (+/−). Regional Nurr1 protein was also investigated at various time points after a seizure induced by pentylenetetrazol (PTZ). Nurr1 protein is expressed in various regions throughout the brain, however, a wide range of Nurr1 expression levels were observed among various neuronal populations. Neurons in the parietal and temporal cortex (secondary somatosensory, insular, auditory, and temporal association cortex) had the highest relative Nurr1 expression (100%) followed closely by the claustrum/dorsal endopiriform cortex (85%) and then subiculum (76%). Lower Nurr1 protein levels were found in neurons in the substantia nigra pars compacta and ventral tegmental area (39%) followed by CA1 (25%) and CA3 (19%) of the hippocampus. Additionally, in the parietal and temporal cortex, two distinct populations of high and medium Nurr1 expressing neurons were observed. Comparisons between +/− and +/+ mice revealed Nurr1 protein was reduced in +/− mice by 27% in the parietal/temporal cortex, 49% in the claustrum/dorsal endopiriform cortex, 25% in the subiculum, 33% in substantia nigra pars compacta, 22% in ventral tegmental area, and 21% in CA1 region of the hippocampus. Based on these data, regional mechanisms appear to exist which can compensate for a loss of a Nurr1 allele. Following a single PTZ-induced seizure, Nurr1 protein in the dentate gyrus peaked around 2 h and returned to baseline by 8 h. Since altered Nurr1 expression has been implicated in neurologic disorders and Nurr1 agonists have showed protective effects, understanding regional protein expression of Nurr1, therefore, is necessary to understand how changes in Nurr1 expression can alter brain function.

Saffron offers hepatoprotection via up-regulation of hepatic farnesoid-X-activated receptors in a rat model of acetaminophen-induced hepatotoxicity.

Objectives:The most important toxicity of acetaminophen is hepatotoxicity. Farnesoid X-activated receptors (FXR) are one of the nuclear receptor superfamily members which have a pivotal role in the bile acid regulation. The objective of the present study was to examine the role of FXR in mediating the hepatoprotective effects of saffron. Methods:Male Wister rats were randomly allocated into five groups including a control, vehicle, acetaminophen and two saffron extract groups of 150 and 300 mg/kg/day. The liver function and hepatic FXR expression were evaluated using biochemical assay and real time RT-PCR, respectively. Data analysis was performed using the one-way ANOVA followed by Duncan's multiple range test. Results:Levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) of the acetaminophen group were significantly higher than the control group whereas those of the extract-treated groups were significantly lower than those of the acetaminophen group. The real time RT-PCR findings showed a non-significant down-regulation of FXR mRNA expression, however, a dose-dependent FXR up-regulation was seen in the groups treated with 150 and 300 mg/kg of the extract for 2.67 (p=0.002) and 10.22 (p=0.0001) fold, respectively. Conclusion:The main finding of the present study was that the hepatic FXR up-regulation had an important role in saffron hepatoprotective activity.

Associations between Pregnane X Receptor and Breast Cancer Growth and Progression.

Pregnane X receptor (PXR, NR1I2) is a member of the ligand-activated nuclear receptor superfamily. This receptor is promiscuous in its activation profile and is responsive to a broad array of both endobiotic and xenobiotic ligands. PXR is involved in pivotal cellular detoxification processes to include the regulation of genes that encode key drug-metabolizing cytochrome-P450 enzymes, oxidative stress response, as well as enzymes that drive steroid and bile acid metabolism. While PXR clearly has important regulatory roles in the liver and gastrointestinal tract, this nuclear receptor also has biological functions in breast tissue. In this review, we highlight current knowledge of PXR’s role in mammary tumor carcinogenesis. The elevated level of PXR expression in cancerous breast tissue suggests a likely interface between aberrant cell division and xeno-protection in cancer cells. Moreover, PXR itself exerts positive effect on the cell cycle, thereby predisposing tumor cells to unchecked proliferation. Activation of PXR also plays a key role in regulating apoptosis, as well as in acquired resistance to chemotherapeutic agents. The repressive role of PXR in regulating inflammatory mediators along with the existence of genetic polymorphisms within the sequence of the PXR gene may predispose individuals to developing breast cancer. Further investigations into the role that PXR plays in driving tumorigenesis are needed.

Isoform-Specific Lysine Methylation of RORα2 by SETD7 Is Required for Association of the TIP60 Coactivator Complex in Prostate Cancer Progression.

The retinoid acid-related orphan receptor α (RORα), a member of the orphan nuclear receptor superfamily, functions as an unknown ligand-dependent transcription factor. RORα was shown to regulate a broad array of physiological processes such as Purkinje cell development in the cerebellum, circadian rhythm, lipid and bone metabolism, inhibition of inflammation, and anti-apoptosis. The human RORα gene encodes at least four distinct isoforms (RORα1, -2, -3, -4), which differ only in their N-terminal domain (NTD). Two isoforms, RORα2 and 3, are not expressed in mice, whereas RORα1 and 4 are expressed both in mice and humans. In the present study, we identified the specific NTD of RORα2 that enhances prostate tumor progression and proliferation via lysine methylation-mediated recruitment of coactivator complex pontin/Tip60. Upregulation of the RORα2 isoform in prostate cancers putatively promotes tumor formation and progression. Furthermore, binding between coactivator complex and RORα2 is increased by lysine methylation of RORα2 because methylation permits subsequent interaction with binding partners. This methylation-dependent activation is performed by SET domain containing 7 (SETD7) methyltransferase, inducing the oncogenic potential of RORα2. Thus, post-translational lysine methylation of RORα2 modulates oncogenic function of RORα2 in prostate cancer. Exploration of the post-translational modifications of RORα2 provides new avenues for the development of tumor-suppressive therapeutic agents through modulating the human isoform-specific tumorigenic role of RORα2.

Bile Acids and Farnesoid X Receptor: Novel Target for the Treatment of Diabetic Cardiomyopathy.

Diabetes mellitus (DM) has become an increasingly common disease with high disability and mortality rates. Diabetes complications are the main cause of diabetes death and about 50% of diabetic patients died from heart disease in developed countries reported by World Health Organization. Diabetic cardiomyopathy (DCM) has been considered as a high incidence and serious complication of DM and plays a key role in the incidence and development of diabetes related heart failure. Metabolism dysregulation is regarded as an important and earlier factor occurred in the pathogenesis of DCM. Insulin resistance, oxidative stress, inflammation and mitochondrial dysfunction also contribute to the development of DCM. Farnesoid X Receptor (FXR) is a member of nuclear receptor superfamily, and plays a critical role in regulating lipid and glucose metabolism, oxidative stress and inflammation. FXR is activated by primary bile acids (BAs) such as chenodeoxycholic acid, cholic acid and synthetic agonists such as obeticholic acid. BAs are the main active ingredients of many natural products and traditional medicines, especially bile or gallstones in animals, such as calculus bovis. Due to the regulatory effect of FXR on glucose and lipid metabolism, oxidative stress and inflammation, the treatment of BAs and FXR agonists for metabolic syndrome and DCM have gained more attention. This review will focus on the pathogenesis of diabetic cardiomyopathy and the regulatory effect of BAs and FXR on DCM.

Role of hepatocyte nuclear factor 4-alpha in gastrointestinal and liver diseases.

Hepatocyte nuclear factor 4-alpha (HNF4α) is a highly conserved member of nuclear receptor superfamily of ligand-dependent transcription factors that is expressed in liver and gastrointestinal organs (pancreas, stomach, and intestine). In liver, HNF4α is best known for its role as a master regulator of liver-specific gene expression and essential for adult and fetal liver function. Dysregulation of HNF4α expression has been associated with many human diseases such as ulcerative colitis, colon cancer, maturity-onset diabetes of the young, liver cirrhosis, and hepatocellular carcinoma. However, the precise role of HNF4α in the etiology of these human pathogenesis is not well understood. Limited information is known about the role of HNF4α isoforms in liver and gastrointestinal disease progression. There is, therefore, a critical need to know how disruption of the expression of these isoforms may impact on disease progression and phenotypes. In this review, we will update our current understanding on the role of HNF4α in human liver and gastrointestinal diseases. We further provide additional information on possible use of HNF4α as a target for potential therapeutic approaches.

Regulation of Brain Cholesterol: What Role Do Liver X Receptors Play in Neurodegenerative Diseases?

Liver X Receptors (LXR) alpha and beta are two members of nuclear receptor superfamily documented as endogenous cholesterol sensors. Following conversion of cholesterol in oxysterol, both LXR isoforms detect intracellular concentrations and act as transcription factors to promote expression of target genes. Among their numerous physiological roles, they act as central cholesterol-lowering factors. In the central nervous system (CNS), cholesterol has been shown to be an essential determinant of brain function, particularly as a major constituent of myelin and membranes. In the brain, LXRs act as cholesterol central regulators, and, beyond this metabolic function, LXRs have additional roles such as providing neuroprotective effects and lowering neuroinflammation. In many neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), Alzheimer’s disease (AD), and multiple sclerosis (MS), dysregulations of cholesterol and oxysterol have been reported. In this paper, we propose to focus on recent advances in the knowledge of the LXRs roles on brain cholesterol and oxysterol homeostasis, neuroinflammation, neuroprotection, and their putative involvement in neurodegenerative disorders. We will discuss their potential use as candidates for both molecular diagnosis and as promising pharmacological targets in the treatment of ALS, AD, or MS patients.

Coronary Artery Disease Related Mir-19A And Mir-26A Are Sensitive To Simvastatin And Ror-Alpha Ligands In Macrophage Cells

Background and Aims: ROR-alpha is a member of ligand-activated nuclear receptor superfamily of transcription factors. Melatonin and cholesterol are two known ligands of ROR-alpha, both of which were shown to be important for atherosclerosis. The aim of this study was to determine differentially expressed miRNAs in coronary artery disease (CAD) patients, and to test the dependence of their expression on ROR-alpha activity in THP-1 macrophage cells.

A comprehensive evaluation of anti-diabetic drugs on nuclear receptor PXR platform

Pregnane & Xenobiotic Receptor (PXR), one of the members of nuclear receptor superfamily, acts as a ‘master-regulator’ of drug metabolism and disposition machinery (DMD). Activation of PXR enables detoxification and elimination of toxic xenobiotics/endobiotics, and defends our body against chemical insults. On the contrary, PXR activation also imposes a serious concern for drug-drug interactions (DDIs). Such DDIs could either decrease the efficacy or lead to accumulation of co-administered drugs at toxic level. Therefore, it is desirable that during drug development process the small drug molecules are screened on PXR-platform prior to their clinical trial and prevent late stage failures. In view of this, we have selected a group of anti-diabetic drug molecules to examine if the success and potential failure of small molecule modulators can be pre-assessed and judiciously correlated on PXR platform. For this purpose, we have examined the PXR activation potential of the selected anti-diabetic drugs. Subsequent to screening of these anti-diabetic drugs, we elaborated the study further with rosiglitazone and pioglitazone (thiazolidinediones, TZDs) which are oral anti-diabetic formulations and have been in controversy owing to their association with cardiotoxicity and bladder cancer respectively. Our study revealed that some of the selected anti-diabetic drugs possess PXR activation potential, implying that these can up-regulate the expression of CYP3A4, UGT1A1, MDR1 and thereby can be predicted to inflict undesirable consequences.