Christian Vaisse, M.D., Ph.D. - US grants

DESCRIPTION (provided by applicant): The long-term objectives of our laboratory are to identify gene mutations that cause obesity in humans and to understand their pathogenic effects. This will provide a more rational approach to the therapy of human obesity. This research proposal focuses on the role of the G-protein coupled Melanocortin-4 Receptor (MC4R) in human obesity. We have shown that this gene is implicated in the first dominantly inherited form of common human obesity and that MC4R mutations cause obesity with a variable penetrance and expressivity. Our hypothesis is that differences in the functional alterations caused by obesity-associated MC4R mutations are the basis for the variable penetrance and expressivity of this genetic form of obesity. To further evaluate the overall role of MC4R in human obesity, to better understand the pathophysiology of human obesity-associated with MC4R mutations and to better evaluate the phenotype-genotype relationship within this form of obesity, we propose the following specific aims: 1) To compare the relative prevalence of different types of melanocortin-4 receptor mutations between large patient cohorts presenting with early or late onset severe obesity. 2) To extensively determine and to compare the nature of the functional alterations caused by the obesity-associated MC4R mutations found in these patient cohorts. 3) To determine if mutations in the MC4R promoter are implicated in human obesity. This study will provide new insights into the role of the MC4R gene in common obesity; promote new hypotheses for the molecular basis of common obesity, and open new avenues for the study of the basic function of MC4R, a major target for the treatment of human obesity.

gene mutation; obesity; genotype; biomarker; gene expression; blood chemistry; gene expression profiling; clinical research; photon absorptiometry; questionnaires; human subject;

[unreadable] DESCRIPTION (provided by applicant): Our long term objectives are to identify gene mutations that cause obesity in humans and to understand their pathogenic effects. We have previously demonstrated that mutations in the Melanocortin-4 receptor (MC4-R), a hypothalamus expressed gene implicated in the central regulation of food intake, cause a common form of obesity in humans. This research proposal focuses on the pro-opiomelanocortin (POMC) gene. This gene is expressed in the arcuate nucleus of the hypothalamus and encodes the physiologic agonist ligands of the MC4R. Homozygous null mutations in the POMC gene result in a rare form of obesity associated with adrenal insufficiency and alterations in hair pigmentation. Recent results in the literature as well as our preliminary findings suggest that heterozygous POMC mutations can predispose to common obesity. Our hypothesis is that a significant number of common severe obesity cases are due to such heterozygous mutations in the POMC gene. To investigate this hypothesis we propose the following specific aims: Aim 1) To determine the prevalence and association of rare POMC gene variants in severe and or early onset human obesity. We will evaluate the prevalence of rare POMC mutations in severe obesity by systematically screening cohorts of severely obese children and adults for mutations in the POMC coding sequence. We will verify the absence of such mutations in non-obese controls. We will analyze the segregation of obesity with the mutations in the families of the probands. We will search for specific phenotypes distinguishing obese POMC mutation carriers from other obese patients. Aim 2) To determine the in vitro effects of obesity associated POMC mutations. Starting with the known obesity-associated heterozygous mutations in the POMC gene, we will systematically evaluate the effects of all the obesity-associated POMC mutations. Specifically we will: 2.1- Examine the effects of human obesity associated POMC mutations on the processing of POMC. 2.2- Examine the effects of mutated human obesity associated POMC derived peptides on MC4R and MC3R activation. 2.3- Test for a toxic effect of human obesity associated POMC mutations on primary cultures of neurons. Aim 3) To determine the effects of obesity associated POMC mutations in vivo. To further confirm the pathogenicity of human obesity associated POMC mutations we will: 3.1- Evaluate the short term effects of mutated human obesity associated POMC derived peptides on food intake in rats. 3.2- Evaluate the long-term effects of transgenic over-expression of human obesity associated POMC mutations in mice. This work will be an additional step towards the genetic classification of obesity in humans and will contribute to the development of targeted preventive and therapeutic interventions based on the underlying genetic defects in the patients. [unreadable] [unreadable]

DESCRIPTION (provided by applicant): Project Summary/Abstract Identification & functional characterization of SIM1 obesity-associated variants Obesity leads to an increased risk for type 2 diabetes, heart attack, many types of cancer, hypertension, stroke, and is estimated to soon be the leading cause of death in the US. Through twin and family studies, obesity has been found to have a 40-70% heritability rate, pointing to a strong genetic etiology. In a large-scale human resequencing project of obese and lean individuals we have discovered that rare coding variants in the Single Minded 1 (SIM1) gene could have a large effect on obesity predisposition. Haploinsuficiency of SIM1 in humans and in heterozygous null Sim1 mice was shown to lead to severe obesity, and a common non- synonymous haplotype predisposes to obesity, suggesting that both altered function and altered expression of SIM1 can lead to obesity susceptibility. In this proposal, we will take advantage of comparative genomics coupled with zebrafish and mouse enhancer assays to identify SIM1 regulatory elements. Using this approach we have already uncovered five hypothalamus enhancers in the SIM1 region. These functional regulatory elements in addition to the SIM1 coding region will be sequenced in several large cohorts of obese and lean individuals in order to uncover obesity-associated variants. Obesity-associated coding variants will be assessed for their effect on the protein function using an in vitro functional assay that we generated for this project. Enhancer variants will be assayed for differential enhancer activity in mice compared to the reference allele. Future assays, such as removal of an obesity-associated enhancer in mice and further sequencing of SIM1 obesity-associated variants in the NIDDK Longitudinal Assessment of Bariatric Surgery (LABS) cohort (a cohort of adults that have undergone bariatric surgery and that is being analyzed for their subsequent outcome) will be considered as a follow-up to this proposal. Identifying and functionally characterizing SIM1 obesity-associated nucleotide variants will increase our understanding of the different genetic contributions of SIM1 to this phenotype. In addition, this study will serve as a model to functionally characterize the effect of noncoding regulatory elements on human disease.

Project Summary/Abstract: Administrative Core The strong nutrition, obesity and metabolism research base at UCSF is distributed today across 44 laboratories within three schools and 12 departments. The primary purpose of the UCSF NORC Administrative Core will be to ensure that all components of the UCSF-NORC are working in unison. This will be achieved by an administrative infrastructure that provides a mechanisms for ensuring the integration of cross-departmental, multidisciplinary research programs and shared research facilities, cohesion in educational/seminar programs and the coordinated facilitation of support for pilot research in emerging research areas. The Administrative Core will provide leadership, infrastructure, administrative support, advice and oversight to all UCSF-NORC operations and to the members of the UCSF-NORC community. The Administrative Core will supply the central support for day-to-day operation and will develop the NORC's long-term visions and strategies. It also will provide the interface to other NIH NORCs, to the NIDDK, and to the lay community. An efficiently operating Administrative Core will facilitate the goal of understanding, and developing new methods to treat, prevent and ultimately cure, the underlying causes and complications of health concerns associated with nutrition, obesity and metabolism. To achieve those aims, the UCSF NORC Administrative Core will: · Facilitate and monitor progress within, and among, the NORC research thematic areas. · Provide oversight of UCSF-NORC shared resources of special need for nutrition, obesity and metabolism studies to enhance the efficiency of human and basic research within the NORC. · Support a Pilot & Feasibility Program to cultivate the development of new sustainable, research programs centered on obesity, nutritional and metabolism themes. · Support an Enrichment Program that both provides research information and fosters collaborations within and among obesity- and nutrition-related research disciplines. · Provide the organizational structure for effective mentoring of NORC investigators. Through its programs and services, the Administrative Core will thus bring together a community of investigators from interrelated disciplines to enhance and extend the effectiveness of nutrition, obesity and metabolism research at UCSF and beyond.

The mission of the proposed UCSF-NORC Enrichment Program is to provide exceptionally high-quality opportunities for investigators at UCSF to exchange research information, for recognized experts in obesity to enlighten the UCSF community on both research and clinical practice, and for faculty to educate trainees, as well as to strengthen the multidisciplinary and collaborative network that links nutrition and obesity research being conducted across UCSF. The Director of the proposed Enrichment Program, Dr. Suneil Koliwad, will be tasked with implementing the Program?s mission. Dr. Koliwad will work with an oversight committee that includes the Center Director, Co- Director, NORC Core and Program Directors, the principal investigators of relevant NIDDK-sponsored T32 training grants, and seminar programs where NORC enrichment-relevant programs are best coordinated such as the UCSF Division of Endocrinology, the Cardiovascular Research Institute (CVRI), the UCSF Center for Obesity Assessment and Treatment (COAST), and the UCSF-affiliated J. David Gladstone Institutes. The specific objectives of the program are to: 1. Strategically design the nutrition and obesity-related components of the weekly UCSF Endocrine Grand Rounds and Obesity & Diabetes Center Seminar Series, including the recruitment of renowned NORC visiting professors from other institutions to present in this series. 2. Oversee the maintenance of an exceptionally high-quality UCSF Obesity Journal Club and Metabolic Research in Progress Seminar (MetaboRIPS) Series, and implement the training components of the NORC mission. 3. Run the proposed Annual NORC Scientific Conference. 4. Help operate collaborative enrichment activities, including proposed NORC/COAST seminars and the annual COAST symposium. 5. Run networking events, such as the NORC/COAST speed networking events, in cooperation with the UCSF Research Development Office (RDO), aimed fostering innovative new collaborative pilot projects. 6. Provide continuing medical education (CME) activities relevant to obesity and nutrition. In achieving these specific objectives, the proposed UCSF-NORC Enrichment Program will realize its proposed mission and its long-term goal of fostering a highly collaborative, world-class learning environment that will advance and promote successful basic, translational, and clinical nutrition and obesity research at UCSF.

UCSF NORC Overview: Summary The UCSF NORC integrates multiple research programs across several different areas of nutrition, obesity and metabolism. Over the last twelve years, UCSF has actively expanded its research base in these critical subject areas, and for the last four years, the NORC has greatly aided the recent phases of this expansion. Specifically, this robust research base has benefitted from an administrative and facilities infrastructure reflecting the diversity of the departments and centers pushing to expand NORC-relevant research at UCSF. Renewal of the NORC will sustain this cohesive programmatic, administrative and shared facilities infrastructure in order to further integrate the already strong research conducted at UCSF, providing a framework for its coordinated future growth. The UCSF NORC includes cellular, animal, translational, clinical, epidemiological, and behavioral research directions. Despite this breadth, these programs are highly interactive with extensive collaborations amongst even the most divergent of programs. For example, radiologists collaborate with clinical scientists to non- invasively visualize metabolism in humans. Human geneticists collaborate with cellular and animal researchers to investigate hypotheses more tractable in those systems. Behavioral scientists coordinate with nutritionists to search for ways to improve outcomes. In all, the 58 interdisciplinary investigators within the UCSF-NORC consist of a mixture of senior and early stage investigators with a collective 78 NIH grants relevant to obesity, metabolism and nutrition research. Their collective goal is to define the underlying mechanisms of disease and to significantly contribute to the prevention and treatment of obesity and its complications. The purpose of the UCSF-NORC is to promote and grow research in obesity, nutrition, and metabolism at UCSF and throughout northern California. This is realized by: · Maintaining, improving, and promoting the interactions and collaborations of researchers in the field with each other and with those outside the field. · Supporting the maintenance and evolution of state-of-the-art Research Cores to meet the needs of obesity, nutrition, and metabolism research. · Facilitating the development of new research directions and the entry of new researchers into the field via Pilot & Feasibility opportunities. · Enriching the NORC research community through pertinent educational forums and other venues that support the development and maintenance of research interactions. · Integrating administrative support to ensure that the infrastructure meets the needs of the local obesity, nutrition and metabolism research community.

? DESCRIPTION (provided by applicant): Our studies address how neuronal primary cilia control obesity. The primary cilium is a cell surface projection that receives and transduces select extracellular signals. In humans, mutations that disrupt the function of primary cilia cause ciliopathies, pleiotropic diseases of which obesity is a cardinal manifestation. How ciliary dysfunction leads to obesity is unclear, but is thought to involve disruption of neuronal signaling pathways that regulate energy homeostasis. The Melanocortin-4 receptor (MC4R) is a central mediator of the regulation of long-term energy homeostasis and mutations in MC4R are the most common monogenic cause of severe human obesity. We have found that MC4R and the recently described MC4R associated protein MRAP2 localize to the primary cilia and that disruption of primary cilia abolishes the anorexigenic function of MC4R in mice. These results suggest three important hypotheses: 1) MC4R functions at the cilium. 2) The endogenous MC4R ligands, ?MSH and AGRP, are sensed by the second order MC4R-expressing neurons through their primary cilia, making this non- synaptic mechanism of modulating neuronal activity an important component of long-term energy homeostasis. 3) Disruption of MC4R signaling is the cause of obesity in ciliopathies. We will test these hypotheses by identifying how MC4R and MRAP2 are targeted to cilia, how ciliopathy-associated proteins participate in MC4R function, and how these proteins signal through cilia to indicate satiety. This work will define molecular and cellular steps of neuronal regulation of energy homeostasis and answer the long-standing question of how ciliary dysfunction causes obesity in humans.

Project Summary/Abstract Obesity leads to an increased risk for type 2 diabetes, heart attack, many types of cancer, hypertension, stroke, and is estimated to soon be the leading cause of death in the US. Through twin and family studies, obesity has been found to have a 40-70% heritability rate, pointing to a strong genetic etiology. The long-term objective of our studies is to determine how genetic variation predisposes humans to obesity and what the therapeutic implications are for this condition. To find common genetic variants associated with obesity, numerous genome-wide association studies (GWAS) have been performed. Over 500 loci have been found to associate with increased body weight index (BMI), all of which reside in noncoding regions of the genome . However, little progress has been made in outlining the causal SNPs and understanding the mechanisms by which they actually cause obesity. In this proposal, we explore the hypothesis that obesity-associated SNPs affect regulatory regions that are active in neuronal sub-population implicated in the regulation of food intake and body weight. Using state-of-the-art approaches that we have recently pioneered through collaborations between the Ahituv and Vaisse laboratories we propose to: - Extend and refine the regulatory landscape of hypothalamic neuronal subpopulations implicated in body weight regulation to identify candidate regulatory elements overlapping obesity GWAS single nucleotide polymorphisms (SNPs). - Use CRISPR inactivation (CRISPRi) in mice to directly test the functional role of regulatory elements that encompass obesity-associated SNPs. - Use CRISPR activation (CRISPRa) in mice to test the therapeutic potential of activity modulation of identified target regulatory regions. Combined, our work will not only provide a regulatory map of neuronal subtypes associated obesity, but also functionally characterize these regions and show their therapeutic potential.

Administrative Core: Summary The strong nutrition, obesity and metabolism research base at UCSF is composed of 58 investigators from 22 departments or organized research units and four schools across 7 UCSF Campuses, as well as UC Berkeley. The primary purpose of the UCSF NORC Administrative Core is to ensure that all components of the UCSF- NORC are working in unison in order to maximally benefit this critical set of investigators. This is achieved by an administrative infrastructure that provides mechanisms to ensure the integration of cross-departmental, multidisciplinary research programs and shared research facilities, cohesion in educational/seminar programs, and the coordinated facilitation of support for pilot research in emerging obesity and nutrition research areas. The Administrative Core provides leadership, infrastructure, administrative support, advice and oversight to all UCSF-NORC operations and to the members of the UCSF-NORC community. The Administrative Core supplies the central support for day-to-day operation and continuously develops the NORC's long-term visions and strategies. It also provides the interface to obesity and nutrition researchers from institutions across Northern California, to other NIH NORCs, to the NIDDK, and to the lay community. An efficiently operating Administrative Core facilitates the goal of understanding, and developing new methods to treat, prevent and ultimately cure, the underlying causes and complications of health concerns related to nutrition, obesity and metabolism. To achieve those aims, the UCSF NORC Administrative Core will continue to: · Facilitate and monitor progress within, and among, the NORC research thematic areas. · Provide oversight of UCSF-NORC shared resources of special need for nutrition, obesity and metabolism studies to enhance the efficiency of human and basic research within the NORC. · Support a Pilot & Feasibility Program to cultivate the development of new sustainable, research programs centered on obesity, nutritional and metabolism themes. · Support an Enrichment Program that both provides research information and fosters collaborations within and among obesity- and nutrition-related research disciplines. · Provide the organizational structure for effective mentoring of NORC investigators. Through its programs and services, the Administrative Core will thus bring together a community of investigators from interrelated disciplines to enhance and extend the effectiveness of nutrition, obesity and metabolism research at UCSF and beyond.!

UCSF NORC Overview: Summary The UCSF NORC integrates multiple research programs across several different areas of nutrition, obesity and metabolism. Over the last twelve years, UCSF has actively expanded its research base in these critical subject areas, and for the last four years, the NORC has greatly aided the recent phases of this expansion. Specifically, this robust research base has benefitted from an administrative and facilities infrastructure reflecting the diversity of the departments and centers pushing to expand NORC-relevant research at UCSF. Renewal of the NORC will sustain this cohesive programmatic, administrative and shared facilities infrastructure in order to further integrate the already strong research conducted at UCSF, providing a framework for its coordinated future growth. The UCSF NORC includes cellular, animal, translational, clinical, epidemiological, and behavioral research directions. Despite this breadth, these programs are highly interactive with extensive collaborations amongst even the most divergent of programs. For example, radiologists collaborate with clinical scientists to non- invasively visualize metabolism in humans. Human geneticists collaborate with cellular and animal researchers to investigate hypotheses more tractable in those systems. Behavioral scientists coordinate with nutritionists to search for ways to improve outcomes. In all, the 58 interdisciplinary investigators within the UCSF-NORC consist of a mixture of senior and early stage investigators with a collective 78 NIH grants relevant to obesity, metabolism and nutrition research. Their collective goal is to define the underlying mechanisms of disease and to significantly contribute to the prevention and treatment of obesity and its complications. The purpose of the UCSF-NORC is to promote and grow research in obesity, nutrition, and metabolism at UCSF and throughout northern California. This is realized by: · Maintaining, improving, and promoting the interactions and collaborations of researchers in the field with each other and with those outside the field. · Supporting the maintenance and evolution of state-of-the-art Research Cores to meet the needs of obesity, nutrition, and metabolism research. · Facilitating the development of new research directions and the entry of new researchers into the field via Pilot & Feasibility opportunities. · Enriching the NORC research community through pertinent educational forums and other venues that support the development and maintenance of research interactions. · Integrating administrative support to ensure that the infrastructure meets the needs of the local obesity, nutrition and metabolism research community.