Ricardo Proenca

Bio: Ricardo Proenca is an academic researcher from Rockefeller University. The author has contributed to research in topics: Nucleic acid & Oligonucleotide. The author has an hindex of 6, co-authored 14 publications receiving 14955 citations. Previous affiliations of Ricardo Proenca include Howard Hughes Medical Institute.

Positional cloning of the mouse obese gene and its human homologue

Abstract: The mechanisms that balance food intake and energy expenditure determine who will be obese and who will be lean. One of the molecules that regulates energy balance in the mouse is the obese (ob) gene. Mutation of ob results in profound obesity and type II diabetes as part of a syndrome that resembles morbid obesity in humans. The ob gene product may function as part of a signalling pathway from adipose tissue that acts to regulate the size of the body fat depot.

Abnormal splicing of the leptin receptor in diabetic mice

Abstract: MUTATIONS in the mouse diabetes(db) gene result in obesity and diabetes in a syndrome resembling morbid human obesity1. Previous data suggest that the db gene encodes the receptor for the obese(ob) gene product, leptin2–7. A leptin receptor was recently cloned from choroid plexus and shown to map to the same 6-cM interval on mouse chromosome 4 as db8. This receptor maps to the same 300-kilobase interval as db, and has at least six alternatively spliced forms. One of these splice variants is expressed at a high level in the hypothalamus, and is abnormally spliced in C57BL/Ks db/db mice. The mutant protein is missing the cytoplasmic region, and is likely to be defective in signal transduction. This suggests that the weight-reducing effects of leptin may be mediated by signal transduction through a leptin receptor in the hypothalamus.

Modulators of body weight, corresponding nucleic acids and proteins, and diagnostic and therapeutic uses thereof

Abstract: The present invention relates generally to the control of body weight of animals including mammals and humans, and more particularly to materials identified herein as modulators of weight, and to the diagnostic and therapeutic uses to which such modulators may be put. In its broadest aspect, the present invention relates to the elucidation and discovery of nucleotide sequences, and proteins putatively expressed by such nucleotides or degenerate variations thereof, that demonstrate the ability to participate in the control of mammalian body weight. The nucleotide sequences in object represent the genes corresponding to the murine and human OB gene, that have been postulated to play a critical role in the regulation of body weight and adiposity. Preliminary data, presented herein, suggests that the polypeptide product of the gene in question functions as a hormone. The present invention further provides nucleic acid molecules for use as molecular probes, or as primers for polymerase chain reaction (PCR) amplification, i.e., synthetic or natural oligonucleotides. In further aspects, the present invention provides a cloning vector, which comprises the nucleic acids of the invention; and a bacterial, insect, or a mammalian expression vector, which comprises the nucleic acid molecules of the invention, operatively associated with an expression control sequence. Accordingly, the invention further relates to a bacterial or a mammalian cell transfected or transformed with an appropriate expression vector, and correspondingly, to the use of the above-mentioned constructs in the preparation of the modulators of the invention. Also provided are antibodies to the OB polypeptide. Moreover, a method for modulating body weight of a mammal is provided. In specific examples, genes encoding two isoforms of both the murine and human OB polypeptides are provided.

The human obese (OB) gene: RNA expression pattern and mapping on the physical, cytogenetic, and genetic maps of chromosome 7

Abstract: The recently identified mouse obese lob) gene apparently encodes a secreted protein that may function in the signaling pathway of adipose tissue. Mutations in the mouse ob gene are associated with the early development of gross obesity. A detailed knowledge concerning the RNA expression pattern and precise genomic location of the human homolog, the OB gene, would facilitate examination of the role of this gene in the inheritance of human obesity. Northern blot analysis revealed that OB RNA is present at a high level in adipose tissue but at much lower levels in placenta and heart. OB RNA is undetectable in a wide range of other tissues. Comparative mapping of mouse and human DNA indicated that the ob gene is located within a region of mouse chromosome 6 that is homologous to a portion of human chromosome 7q. We mapped the human OB gene on a yeast artificial chromosome {YAC) contig from chromosome 7q31.3 that contains 43 clones and 19 sequence-tagged sites {STSs). Among the 19 STSs are eight corresponding to microsatellite-type genetic markers, including seven {CA}n repeat-type Genethon markers. Because of their close physical proximity to the human OB gene, these eight genetic markers represent valuable tools for analyzing families with evidence of hereditary obesity and for investigating the possible association between OB mutations and human obesity.

Mammalian ob polypeptides capable of modulating body weight, corresponding nucleic acids, and diagnostic and therapeutic uses thereof

Abstract: The present invention relates generally to the control of body weight of animals including mammals and humans, and more particularly to materials identified herein as modulators of weight, and to the diagnostic and therapeutic uses to which such modulators may be put In its broadest aspect, the present invention relates to the elucidation and discovery of nucleotide sequences, and proteins putatively expressed by such nucleotides or degenerate variations thereof, that demonstrate the ability to participate in the control of mammalian body weight The nucleotide sequences in object represent the genes corresponding to the murine and human ob gene, that have been postulated to play a critical role in the regulation of body weight and adiposity Preliminary data, presented herein, suggests that the polypeptide product of the gene in question functions as a hormone The present invention further provides nucleic acid molecules for use as molecular probes, or as primers for polymerase chain reaction (PCR) amplification, ie, synthetic or natural oligonucleotides In further aspects, the present invention provides a cloning vector, which comprises the nucleic acids of the invention; and a bacterial, insect, or a mammalian expression vector, which comprises the nucleic acid molecules of the invention, operatively associated with an expression control sequence Accordingly, the invention further relates to a bacterial or a mammalian cell transfected or transformed with an appropriate expression vector, and correspondingly, to the use of the above mentioned constructs in the preparation of the modulators of the invention Also provided are antibodies to the ob polypeptide Moreover, a method for modulating body weight of a mammal is provided In specific examples, genes encoding two isoforms of both the murine and human ob polypeptides are provided

Serum Immunoreactive-Leptin Concentrations in Normal-Weight and Obese Humans

Abstract: Background Leptin, the product of the ob gene, is a hormone secreted by adipocytes. Animals with mutations in the ob gene are obese and lose weight when given leptin, but little is known about the physiologic actions of leptin in humans. Methods Using a newly developed radioimmunoassay, we measured serum concentrations of leptin in 136 normal-weight subjects and 139 obese subjects (body-mass index, >27.3 for men and >27.8 for women; the body-mass index was defined as the weight in kilograms divided by the square of the height in meters). The measurements were repeated in seven obese subjects after weight loss and during maintenance of the lower weight. The ob messenger RNA (mRNA) content of adipocytes was determined in 27 normal-weight and 27 obese subjects. Results The mean (±SD) serum leptin concentrations were 31.3±24.1 ng per milliliter in the obese subjects and 7.5±9.3 ng per milliliter in the normal-weight subjects (P<0.001). There was a strong positive correlation between serum leptin concentration...

Central nervous system control of food intake

Abstract: New information regarding neuronal circuits that control food intake and their hormonal regulation has extended our understanding of energy homeostasis, the process whereby energy intake is matched to energy expenditure over time. The profound obesity that results in rodents (and in the rare human case as well) from mutation of key signalling molecules involved in this regulatory system highlights its importance to human health. Although each new signalling pathway discovered in the hypothalamus is a potential target for drug development in the treatment of obesity, the growing number of such signalling molecules indicates that food intake is controlled by a highly complex process. To better understand how energy homeostasis can be achieved, we describe a model that delineates the roles of individual hormonal and neuropeptide signalling pathways in the control of food intake and the means by which obesity can arise from inherited or acquired defects in their function.

Adipose Tissue as an Endocrine Organ

Abstract: Adipose tissue is a complex, essential, and highly active metabolic and endocrine organ. Besides adipocytes, adipose tissue contains connective tissue matrix, nerve tissue, stromovascular cells, and immune cells. Together these components function as an integrated unit. Adipose tissue not only responds to afferent signals from traditional hormone systems and the central nervous system but also expresses and secretes factors with important endocrine functions. These factors include leptin, other cytokines, adiponectin, complement components, plasminogen activator inhibitor-1, proteins of the renin-angiotensin system, and resistin. Adipose tissue is also a major site for metabolism of sex steroids and glucocorticoids. The important endocrine function of adipose tissue is emphasized by the adverse metabolic consequences of both adipose tissue excess and deficiency. A better understanding of the endocrine function of adipose tissue will likely lead to more rational therapy for these increasingly prevalent disorders. This review presents an overview of the endocrine functions of adipose tissue.

Obesity alters gut microbial ecology

Abstract: We have analyzed 5,088 bacterial 16S rRNA gene sequences from the distal intestinal (cecal) microbiota of genetically obese ob/ob mice, lean ob/+ and wild-type siblings, and their ob/+ mothers, all fed the same polysaccharide-rich diet. Although the majority of mouse gut species are unique, the mouse and human microbiota(s) are similar at the division (superkingdom) level, with Firmicutes and Bacteroidetes dominating. Microbial-community composition is inherited from mothers. However, compared with lean mice and regardless of kinship, ob/ob animals have a 50% reduction in the abundance of Bacteroidetes and a proportional increase in Firmicutes. These changes, which are division-wide, indicate that, in this model, obesity affects the diversity of the gut microbiota and suggest that intentional manipulation of community structure may be useful for regulating energy balance in obese individuals.

Leptin and the regulation of body weight in mammals

Abstract: The assimilation, storage and use of energy from nutrients constitute a homeostatic system that is essential for life In vertebrates, the ability to store sufficient quantities of energy-dense triglyceride in adipose tissue allows survival during the frequent periods of food deprivation encountered during evolution However, the presence of excess adipose tissue can be maladaptive A complex physiological system has evolved to regulate fuel stores and energy balance at an optimum level Leptin, a hormone secreted by adipose tissue, and its receptor are integral components of this system Leptin also signals nutritional status to several other physiological systems and modulates their function Here we review the role of leptin in the control of body weight and its relevance to the pathogenesis of obesity