ORPHAN NUCLEAR RECEPTORSBiology and Ligand Identification

View Electronic Brochure (PDF)

Overview

Attention: Agenda updated as of May 16th!!

Pharmaceuticals directed at known ligands of nuclear receptors comprise some of the most successful selling drugs in the industry. Recent research has shown that many of these receptors are associated with metabolic diseases by regulating genes after being activated by small hormones.

This conference specifically provides you with the state-of-the-art knowledge on Orphan Nuclear Receptors, ligand - activated transcription factors whose ligands are NOT identified yet. This fact provides an enormous opportunity for the development of new therapeutic agents and makes them an ideal new target.

physiological functions of orphan receptors
* Effect of LXR on lipid metabolism
* Function of COUP-TFI in the neuronal development
* Novel compounds, regulating the transcriptional activity of the extended estrogen receptor family
* Interaction of BXR, SXR, PXR and CAR with xenobiotics

novel methods for ligand identification
* Using transcriptional profiling to identify new genes
* The latest in vitro fluorescent assay methods
* Using selective peptide probes in order to identify novel compounds that bind to unliganded receptors
* Tagging of genes, responsive to nuclear hormone receptors, in stable cell lines

Don't miss the opportunity to discuss the latest findings on orphan nuclear receptors and the next steps taken to discover their yet unknown ligands with the
top experts!

RELATED LINKS

Agenda

Monday, May 21, 2001

8:15 Registration, Exhibit and Poster Set Up, Coffee and Pastries

9:00 Chairperson's Opening Remarks
Timothy M. Willson, Ph.D., Nuclear Receptor Discovery Research, GlaxoSmithKline

Lipid metabolism

9:40 Orphan Receptors as Drug Discovery Targets for Cardiovascular Disease
Ira Schulman, Associate Director Biology, X-Ceptor Therapeutics, Inc.
X-Ceptor Therapeutics has developed a broad based drug discovery platform focusing on the identification and development of ligands for orphan nuclear receptors for the treatment of human disease. To achieve these goals we have implemented an integrated research approach that includes molecular biology, chemistry, high throughput screening and pharmacology. We have developed cell based transfection and biochemical assays to routinely screen greater than 35,000 single compounds per day in a 384-well format. Both our cell-based and biochemical assays have also been validated in a 1536-well format for a potential capacity of ~150,000 single compounds per day. We have employed this technology toward the orphan receptors, LXR and FXR to identify leads compounds. Our parallel synthesis chemistry efforts have employed hit to lead chemistry to identify potent and selective ligands for these orphan receptors. Modulators of LXR and FXR control key genes involved in decreasing cholesterol absorption in the intestine, altering bile acid synthesis in the liver and disposing of excess cholesterol in lipid accumulating cells in the coronary arteries. The current findings suggest that these receptors serve as new molecular targets for drugs that could be effective in the treatment and/or prevention of diseases such as atherosclerosis.

10:15 Orphan Nuclear Receptors: New Hormone Signaling Pathways and Drug Discovery Opportunities
Jurgen M. Lehmann, Nuclear Receptors Program Director, Tularik, Inc.*
Nuclear receptors comprise a large family of ligand-activated transcription factors that play critical roles in nearly all aspects of development and adult physiology by regulating complex gene programs in response to small lipophilic hormones, such as steroid hormones, retinoic acid, thyroid hormone, and vitamin D. In addition to the receptors with known endogenous ligands, the nuclear receptor family also includes many "orphan" receptors for which ligands have yet to be identified. These orphan receptors not only provide opportunities to characterize novel signal transduction pathways but also may be new potential drug targets. We will present our recent progress in the identification of ligands for orphan receptors and the use of these ligands in functional genomic approaches to explore orphan receptor biology. *In collaboration with Peter Coward, Tim Hoey, Frank Kayser, Kevin Lustig, Bei Shan, and Andrew K. Shiau, Tularik Inc.

10:50 Refreshment Break and Exhibit/ Poster Viewing

Orphan receptors and xenobiotics

11:15 PXR: A Key Regulator of Xenobiotic and Bile Acid Homeostasis
John T. Moore, Ph.D., Nuclear Receptor Discovery Research, GlaxoSmithKline
The discovery and characterization of PXR has led to an increased understanding of the molecular basis of xenobiotic and bile acid metabolism. In response to a diverse array of xenobiotic ligands (including macrolide antibiotics, antimycotics, statins, and glucocorticoids), PXR induces expression of the cytochrome P450 3A monooxygenase (Cyp3A) gene. Given the importance of CYP3A activity in drug metabolism and excretion, this link has important consequences in the drug interaction field. More recently, ligand screening of endogenous compounds has shown that PXR is also activated by certain bile acids such as lithocholic acid and its 3-keto metabolite. We will present evidence that PXR serves as a physiological sensor of lithocholic acid and coordinately regulates genes involved in bile acid metabolism in order to reduce the concentrations of this toxic bile acid. These findings are consistent with a general role of PXR in hepatoprotection and furthermore suggest that PXR agonists may be a useful target for the treatment of human cholestatic liver disease. Evidence from our recent mouse knock-out model support the essential role of PXR in regulation of these processes. Finally, we will present a comparative pharmacological analysis of PXRs from a wide spectrum of vertebrate species. These data provide a better understanding of the phylogenetic and functional relationships between PXR homologs.

11:50 SXR: A Coordinate Regulator of Drug Clearance in the Liver and Intestine
Barry M. Forman, M.D., Ph.D., The Beckman Research Institute at City of Hope, Gonda Research Center, Department of Molecular Medicine
SXR has been shown to play a key role in regulating drug metabolism in the liver. We now show that it can regulate drug efflux in the intestine. This extends the role of SXR to include two critical steps of the drug clearance pathway.

12:25 Luncheon, sponsored by The Knowledge Foundation, Inc.

Orphan receptors and xenobiotics II

1:40 Chairperson's Remarks
Barry M. Forman

1:45 The Orphan Receptor BXR and Xenobiotic Metabolism
Bruce Blumberg, Ph.D., Assistant Professor, Dept. of Developmental & Cell Biology, UC Irvine
Abstract not available at time of print

2:20 Regulation of Drug Metabolism by the Xenobiotic Receptor CAR
David D. Moore, Ph.D., Professor, Department of Molecular and Cellular Biology, Baylor College of Medicine
From foods, environmental pollutants, drugs and other sources, organisms encounter a wide range of foreign compounds. Cytochrome P450 (CYP) enzymes metabolize such xenobiotics and thus provide a primary defense against their potential deleterious effects. Induction of expression of specific CYPs in response to particular xenobiotics is an important aspect of this response. The nuclear receptor CAR mediates the specific response to a class of xenobiotics known as the "phenobarbital-like inducers". Thus, mice lacking the CAR gene are completely unable to activate Cyp2b10 gene expression in response to such inducers. They also show decreased metabolism of the classic CYP substrate zoxazolamine and a complete loss of the liver hypertrophic response to these inducers. Cocaine causes acute hepatotoxicity in wild-type mice treated with phenobarbital-like inducers and this toxicity is absent in the CAR-deficient animals. Thus, loss of CAR function alters sensitivity to toxins, increasing or decreasing it depending on the compound. Modulation of CAR activity in humans may significantly affect metabolism of drugs and other xenobiotics. Since the human and rodent CAR protein differ in their responses to individual inducers, it will be worthwhile to develop screening systems based on the human CAR gene to identify compounds with undesirable effects on drug metabolism among potential drug candidates.

new frontiers in orphan nuclear receptors

3:00 Nuclear Orphan Receptor Coup-TFI in Cerebral Cortical Lamination and Axon Myelination
Ming-Jer Tsai, Professor, Department of Molecular and Cell Biology and Department of Medicine, Baylor College of Medicine*
To understand the physiological functions of orphan receptors, COUP-TFI, we have deleted it in mice by homologous recombination. More than 98% of COUP-TFI null mutant mice die shortly after birth due to the aberrant formation of the ninth ganglion and defect in axon guidance, affecting the ability of the null mutant mice to feed. Thus, the null mutant mice die of dehydration and malnutrition, reconfirming the notion that COUP-TFI is essential for neural development. In addition, these null mice have major defects in the central nervous system, including malformation of cortical layers, failure of axons of corpus callosum and hippocampal commissures to cross the midline and severe reduction of axon myelination in CNS and PNS. These defects are largely contributed by inappropriate differentiation of neurons, or its surrounding cells, in the absence of COUP-TFI. In addition, regionalization of forebrain, that is important for defining the functional domains of visual, somatosensory and motor cortexes, is largely disrupted in the COUP-TFI null mutants. These results further substantiate COUP-TFI as a major player in regulating many aspects of neuronal function.* In collaboration with Cheng, Zhou, 1 Yuhong Qiu, 1 Fred A. Pereira, 1 Michael C. Crair, 2 and Sophia Y. Tsai, 1 1Department of Molecular and Cell Biology and 2 Division of Neuroscience, Baylor College of Medicine

3:35 The Extended Estrogen Receptor Family (ERs and ERRs): Genes, Functions and Shared Ligands
Vincent Giguere, Ph.D., Professor and Director, Molecular Oncology Group, McGill University Health Centre, Royal Victoria Hospital, Montreal, Canada
Nuclear receptors constitute a large family of transcription factors that mediate responses to small lipophilic hormones and play essential roles in embryonic development and maintenance of homeostasis in adult animal. Orphan nuclear receptors are members of the nuclear receptor family that lack identified ligands. Recent studies have identified several natural and synthetic ligands for a number of orphan nuclear receptors, which led to the discovery of new hormone response systems implicated in the control of cell fate, organogenesis and basic metabolic functions. While the estrogen-receptor-related receptor (ERRs) were the first orphan nuclear receptors identified more than a decade ago, the identification of natural and synthetic ERR ligands has remained elusive. Despite being closely related to the estrogen receptors, ERRs are not activated by natural estrogens. In contrast, members of the ERR family display various levels of constitutive activity and can interact with co-activators in the absence of ligand. We will present a series of evidence that ERs and ERRs play complementary functions in development and physiology and that a certain class of synthetic drugs can simultaneously regulate the transcriptional activity of both type of receptors. These novel compounds, referred to as SERMplus, have the potential to possess a broader therapeutic index that current SERMs.

4:10 Refreshment Break and Exhibit/Poster Viewing

4:40 HNF4: Non Ligand-Dependent Mechanisms of Regulating a Nuclear Receptor
Frances M. Sladek, Associate Professor of Cell Biology, Dept. of Cell Biology & Neuroscience, University of California, Riverside
Hepatocye nuclear factor 4 (HNF4), a highly conserved member of the nuclear receptor superfamily, regulates the transcription of many essential genes involved in intermediary metabolism and is linked to human diseases such as diabetes, hemophilia, atherosclerosis and cancer. HNF4 exhibits unique dimerization and transactivation functions, activating transcription in a constitutive fashion and interacting with both co-repressors and co-activators in a ligand-independent fashion.

5:15 Diversity and Function of Orphan Nuclear Receptors in Nematodes
Ann E. Sluder, Ph.D., Cambria Biosciences LLC, Bedford, MA
Orphan nuclear receptors (NRs) are the most abundant transcriptional regulators encoded in the genome of the free-living nematode Caenorhabditis elegans, with >250 predicted NR genes. While several NR classes conserved in vertebrates and insects are represented in C. elegans, most nematode NR genes are distinct from those known in other phyla. Homologues of some diverged C. elegans NR genes are known from other nematode species, revealing nematode-specific diversity within the NR superfamily. Functional studies are revealing roles for the genes in a variety of events in the nematode life-cycle.

5:50 End of Day One

Tuesday, May 22, 2001

8:15 Exhibit/ Poster Viewing, Coffee and Pastries

Ligand Identification

9:00 Chairperson's Opening Remarks

Jurgen M. Lehmann, Nuclear Receptors Program Director, Tularik, Inc.

9:05 In Vitro Fluorescent Assay Methods for Identification and Characterization of Nuclear Receptor Ligands
Robert G. Lowery, Vice President, R&D, PanVera Corporation
Fluorescence based assay methods including fluorescence polarization (FP) and fluorescence resonance energy transfer (FRET) allow real time measurement of equilibrium binding in solution in a high throughput format. This talk will provide an overview of how these approaches can be used to measure nuclear receptor ligand binding and interaction with coactivator proteins, using the classical steroid hormone receptors (ER, PR, and GR) as model systems.

9:40 Tools for the Identification of Novel Compounds to Nuclear Receptors and Their Orphans
Dr. Anna Wilhelmsson, Karo Bio, Sweden
Selective peptide probes have been used in a number of in vitro and cell-based high-throughput formats to identify novel compounds that bind to nuclear receptor molecules in a selective manner. Although most of our peptides are directed to sites formed by binding to receptor forms modulated by known ligands, we have identified several peptide probes that specifically bind only to the unliganded form of the receptor. Such probes represent ideal starting points for selection of compounds from combinatorial libraries that alter this probe binding. This approach offers a rapid and useful method for providing research tools for biological studies and receptor modeling.

10:15 Humanizing Yeast for Nuclear Receptor Functional Analysis
Tauseef R. Butt, Ph.D., Vice President of R&D, LifeSensors, Inc.
Genomic information is likely to increase the number of orphan nuclear receptors as potential therapeutic and diagnostic targets. There is a need to develop rapid and facile methods to uncover the function of these receptors in health and disease. Yeast is remarkable in recapitulating the ligand dependent functions of human nuclear receptors. Ligand dependent function of human estrogen, thyroid hormone and other receptors in yeast will be discussed. Role of human co-activator and co-repressor ligand mediated function in yeast will be described. Our goal is to capture human genes that mimic human-like responses for nuclear receptors in yeast. Applications of this technology to orphan nuclear receptors will be discussed.

10:50 Refreshment Break and Poster/Exhibit Viewing

11:15 Assembly of Transcription-Based Nuclear Receptor Assays with Genome Screening Methods
James Crute, Discovery Biology-Gene Expression Group, Aurora Biosciences Corporation*
Using a proprietary gene-tagging technology (the GenomeScreenTM system), it has been possible to create stable cell lines where endogenous genes responsive to nuclear hormone receptor (NHR) activation are tagged with the sensitive reporter b-lactamase. Tagged genes can be molecularly characterized by 5' and 3' RACE methods and grouped with respect to their identity. Further cell line characterization permits identification of individual clones capable of serving as HTS-compatible assays for identifying new types of modulators of NHR signaling. Model NHR signaling systems will be described, including the tagging of estrogen receptor-a-responsive genes. This work will also document the value of using GenomeScreenTM technology in certain situations to measure the pharmacological modulation of endogenous NHR activity.
* In collaboration with Alexandra Bernardino, Marek Liyanage, and Mariko Riley, Discovery Biology-Gene Expression Group, Aurora Biosciences Corporation

Structure and function of orphan receptors

11:50 Nuclear Receptors Ligand Identification through Functional Gene-based Assay Platform
Fabrice Piu, Ph.D., Principal Scientist, Signal Transduction Group, ACADIA Pharmaceuticals Inc.
ACADIA has developed a proprietary functional gene-based platform that allows for precise pharmacological characterization of drug target genes (Receptor and Selection Amplification Technologies, R-SATTM). This technology was successfully applied to various known and orphan nuclear receptors, leading to a detailed description of receptor function. For instance, unique signaling requirements based upon involvement of co-activators and kinases were identified for each nuclear receptor. Furthermore, levels of constitutive activity exhibited by nuclear receptors could be reliably quantified. R-SATTM thus offers an attractive and powerful assay to rapidly identify surrogate ligands for various receptor targets, without the need for knowledge of prior ligands.

12:25 Structure and Function of the PPARs
Timothy M. Willson, Ph.D., Nuclear Receptor Discovery Research, GlaxoSmithKline
We have determined the X-ray crystal structure of the ligand binding domains of human PPARa, PPARg, and PPARd. The structures reveal a common mechanism of ligand activation of these receptors, which can be exploited to develop PPAR agonists and antagonists. Significant differences in the shapes of the ligand binding pockets between the PPAR subtypes are also apparent. Through the use of combinatorial chemistry and structure-based drug design, we have developed potent and subtype-selective ligands for each of the three PPARs. These ligands have been used as chemical tools to examine the function of these orphan receptors as metabolic regulators of lipid and carbohydrate metabolism.

1:00 End of Conference

Call for Posters

Selected Oral Presentations and Call for Posters
Industry and academic scientists are encouraged to submit poster titles for this event. One-page abstracts (8 1/2” x 11” with 1-inch margins) must be submitted no later than April 16, 2001 for inclusion in conference documentation. Additional poster submissions will be accepted until May 1, 2001 but may not be included in conference documentation.
Note: If you are submitting a poster, you MUST be registered and paid in advance to ensure that a posterboard is reserved for you.

Sponsorship & Exhibit Opportunities
Take advantage of tailored opportunities to reach a very targeted, decision-making audience. We offer a variety of packages, each designed to maximize your organization's exposure and facilitate networking at this event. Don't miss this opportunity to showcase your products to a large audience of attendees qualified to make purchasing decision as well as demonstrate your company's position as a leader in this market.

Conference Sponsorships
A variety of conference sponsorships are available which offer incremental levels of visibility to conference delegates at the event - as well as opportunities for marketing exposure prior to the event. Taking advantage of pre-conference options has the added benefit of getting your organization's name out to a large group of interested decision makers.

Networking Event Sponsorships
These "mini" sponsorships offer representatives of your organization a dedicated opportunity to network with conference delegates - with your organization clearly recognized as the host of the event.

• Cocktail Receptions
• Luncheons
• Dinner Banquets
• Hospitality Suites

Workshop Sponsorships
Your company may sponsor an instructional workshop (subject to approval) for delegates in conjunction with the conference. Highlight your organization's expertise! Delegate feedback indicates that these scientific/technical vehicles enhance retention of your organization's presence in their minds - increasing the potential for drawing customers long after the conference is over.

Call Alan Abend at (617) 232-7400 ext. 202 or email today for pricing information and customization options.

Register

Register me for this exciting conference!