RESEARCH HIGHLIGHTS AND ACCOMPLISHMENTS

The mission of the California National Primate Research Center is to provide interdisciplinary programs in biomedical research on significant human health-related problems in which nonhuman primates are the models of choice. In the past few years, a variety of research opportunities were provided to staff and collaborative scientists. These researchers reported projects encompassing many phases of biology and medicine, including AIDS and other infectious diseases, reproduction, infertility, neurodegenerative diseases such as Alzheimer's, nutrition, cystic fibrosis, asthma, xenotransplantation, and behavior. The following are examples of the CNPRC's accomplishments from the past few years:

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BRAIN, MIND AND BEHAVIOR UNIT

The Brain, Mind and Behavior Unit provides services, training, consulting and collaborative expertise in the areas of basic neuroscience, stress physiology, psychoneuroimmunology, cognitive neuroscience, and psychosocial processes in nonhuman primates. Particular emphasis in the Unit is on studying the interrelations of processes at multiple levels of analysis: social, psychological, neuroendocrine, and neurobiological.

CNPRC research scientists in this unit have conducted:

• Research on the monkey model of Alzheimer’s which has proven the effectiveness of nerve growth factor in preventing cell death in aging brains. This research has led to the first human clinical trial of gene therapy for Alzheimer’s Disease.

• Work in collaboration with the U.C. Davis M.I.N.D. Institute, to study the nonhuman primate model of autism and to look at possible causes of the disease. According to the California Department of Developmental Services, the number of autistic children and adults increased by 273 percent from 1987 to 1998.

• Research on the neuroimmune mechanisms by which stress affects health, to try and understand why some individuals are more at risk than others for stress-induced health problems, and to determine the role that chronic stress plays in disease.

• Studies on the changes that take place in brains and in behavior as a result of normal aging processes, and whether, in post-menopausal women, hormone replacement can reverse these effects. These studies of aging in macaques have led to clinical trials evaluating the efficacy of estrogen treatment for cognitive decline. Because of the similarity in reproduction, monkeys are valuable animal models for such studies.

• Behavioral studies to identify critical factors in development of social skills in young monkeys.

• Studies of the organization of somatosensory cortex in titi monkeys that have revealed that this highly social, monogamous nonhuman primate exhibits an unusually large representation of hairy skin in its primary somatosensory cortex, suggesting unique patterns of cortical organization that support the monogamous life-style.

• Research demonstrating that simian immunodeficiency virus replicates in close proximity to catecholamine-containing nerves in lymph nodes.

• Studies demonstrating that affiliative social preferences in juvenile monkeys are related to temperamental characteristics identified in infancy.

• A project showing that postnatal iron deprivation results in cognitive deficits, as well as heightened emotionality.

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REPRODUCTIVE SCIENCES UNIT

Staff Scientists in the Reproductive Sciences Unit have made substantial research and service contributions, and are committed to training the next generation of investigators with expertise in nonhuman primates. Unit research efforts have focused on reproductive endocrinology and aging, gamete biology, fetal development and disease, and stem cells and gene therapy. Stem cells hold great potential for treating a variety of illnesses. While blood stem cells are currently used clinically, safety and benefit of other stem and progenitor cell populations must be shown before they can be used in humans. One of two national NIH-supported Centers of Excellence in Translational Human Stem Cell Research and the only NHLBI-supported Center for Fetal Gene Transfer for Heart, Lung, and Blood Diseases is located in the Reproductive Sciences Unit at the CNPRC. Ground-breaking research using a variety of stem and progenitor cells is currently in progress, and new gene transfer and in vivo imaging techniques are being explored which will provide a very powerful tool to determine the fate of cells after administration to human patients.

Researchers at the CNPRC have:

• Studied the effects of estrogen replacement and the menopausal transition to identify the hormonal basis of “healthy aging” in women.

• Demonstrated that dioxin causes ovarian toxicity, with effect on estrogen production the primary effect.

• Showed that the trophoblast is the target for the toxic action of a by-product of drinking water chlorination, bromodichloromethane.

• Showed that older female macaques in the third decade of life and women in the sixth decade of life experience the same endocrine changes which are linked to the adrenal gland.

• In collaboration with investigators in the Brain, Mind and Behavior Unit showed that during puberty, exposure to a weak environmental estrogen, nonylphenol, results in both anatomical and endocrine changes that are long-lasting.

• Developed biomarker assays for reproductive studies with monkeys and with humans, emphasizing the translational nature of this work.

• Showed the ability of new contraceptive vaccines to block implantation and sperm production.

• Conducted studies on the mechanism of virus (HIV) entry into the placenta, and trophoblast cells in particular, which has important implications for understanding maternal-fetal HIV transmission.

• Developed an ovarian cell culture model to study ovarian function, the role of different hormones during the peri-implantation phase of early pregnancy, and the effects of environmental toxins. (Alternatives to Animals in Research)

• Used in vivo techniques for the successful recovery of mature and immature oocytes that are used to develop methods for in vitro maturation and cryopreservation of nonhuman primate oocytes.

• Identified new ways to treat congenital diseases of the heart, lung, and blood using fetal gene therapy.

• Demonstrated the effectiveness of in vivo imaging techniques for assessing gene expression longitudinally and over time.

• Showed that fetal and infant rhesus monkey mesenchymal stem cells can readily grow and differentiate into cells of mesenchymal origin, that lentiviral vectors can readily transduce these cells without altering differentiation potential, and that there are age-related differences when comparing fetal to adult populations.

• Developed new PCR-based techniques to determine fetal gender and quantify fetal DNA concentrations in maternal blood in order to enhance our understanding of fetal:maternal microchimerism.

• Demonstrated that fetal CD34+ cells readily cross the placenta and can be detected in the maternal circulation, and that fetal cells can remain in maternal tissues for a lifetime comparable to humans.

• Studied the pathogenesis of obstructive renal dysplasia, a major cause of renal failure in children, and showed the role of podocyte loss in determining long-term renal function associated with this condition.

• Used a highly effective antiretroviral agent during pregnancy and showed that tenofovir can cross the placenta in sufficient quantities to significantly reduce fetal viral loads, and result in healthy newborns free of disease at term.

• Developed preclinical pediatric models of non-myeloablative conditioning.

• Obtained data instrumental for a Phase I clinical trial in humans for stem cell therapy for AIDS lymphoma.

• Performed pre-clinical studies to support IND applications for pediatric therapyies for muscular dystrophies.

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RESPIRATORY DISEASES UNIT

The CNPRC Respiratory Diseases Unit is conducting pioneering research on the relationships between air pollution, common allergies, and asthma. Research has shown for the first time that occasional exposure to ozone can change how the lungs of young monkeys develop, leading to a disease similar to childhood asthma in humans. Research in this area may help doctors in smoggy cities combat the rise of asthma in young children. More than 17 million people in the U.S. have asthma, according to the Asthma and Allergy Foundation of America.

Researchers at the CNPRC have:

• Shown that occasional exposure to ozone can change how the lungs of young monkeys develop, leading to a
disease similar to childhood asthma in humans.

• Researched the long term effects of air pollution on our lungs and overall health.

• Observed airway hyper-reactivity and neuroendocrine cell hypertrophy that could lead to lasting adverse consequences, namely asthma, following both prenatal and postnatal exposure to environmental tobacco smoke.

• Shown that ozone exposure has an immunomodulatory effect on the pulmonary response to allergens, with distinct differences in airway immune cell phenotype depending upon age.

• Shown that house dust mite allergen inhalation during postnatal development results in the increased septation of parenchymal tissue with more, smaller alveoli.

• Shown that ozone inhalation during postnatal development results in the decreased septation of parenchymal tissue, with increases in lung volume. Also observed a compensatory mechanism of conversion of respiratory bronchioles into alveolar ducts to maintain the number of alveoli during lung growth.

• Shown that ozone inhalation amplifies the allergic and structural remodeling effects of house dust mite allergen sensitization and inhalation.

• Developed and validated an airway isolation method for evaluating the biology of specific airway generations within the context of their branching history and three-dimensional architectural position within the airways.

• Invented and validated a method for isolating proteins from the epithelium of the intact airway with high fidelity.

• Invented and validated a three-dimensional approach to defining the distribution of cells and sub-cellular contents based on position within the airway tree.

• Developed and validated a model of allergic airways disease in infants, young children and adults using a human allergen.

• Developed and validated methods for isolating individual airway branches from the airway tree in an intact and viable state for long term explant culture. (Alternatives to Animals in Research)

• Developed a panel of monoclonal antibodies and an ELISA assay for quantifying respiratory mucin, which is currently used worldwide as the standard for assaying mucus production.

• Shown that prior exposure to house dust mite allergen or ozone markedly enhances the reactive metabolite formation from 1-nitronaphthalene, which generates reactive metabolites that produce Clara cell injury via cytochrome P450 monooxygenases.

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VIROLOGY & IMMUNOLOGY UNIT

The Virology and Immunology Unit provides unique expertise and a collaborative setting for the study of infectious and immunologic diseases affecting humans, at the whole animal, organ, cellular and molecular levels. The research projects in this unit include pathogenesis of SIV/HIV and opportunistic infections, antiviral immunity, immunity of the genital tract, mucosal transmission of viruses, immunodeficiencies/prophylactics, antiviral therapies, vaccines, viral diagnostics and epidemiology. The Unit scientists are intensely involved in studies directly related to HIV vaccine development.

SAIDS (Simian AIDS) is an autoimmune disease that results from an SIV infection, just as AIDS in humans results from HIV. Macaque monkeys that have SAIDS are ideal models to study the prevention of HIV infection and pathology of AIDS in humans. Monkeys and humans have similar physiology, drug metabolism, placentation and fetal development. The SIV model is useful in vaccine development, understanding how the AIDS virus works, and in preventing and delaying the onset of the disease in infected people.

Researchers at the CNPRC have:

• Discovered that treatment of neonatal monkeys with tenofovir stops mother to infant SIV transmission

• Defined the biology of HIV sexual transmission

• Established the first breeding colony to produce genetically defined rhesus macaques for AIDS research. Virology and Immunology scientists provided the genetic expertise and leadership that led to the establishment of the first breeding colony to produce MamuA*01 rhesus macaques for AIDS research.

• Established a system to study mechanisms of thymus dysfunction in the macaque model of pediatric AIDS.

• Used vaccines and antivirals to prevent SIV infection and disease in infant macaques.

• Defined the initial target cells in vaginal SIV transmission.

• Applied the rhesus monkey measles models to study ways of blocking infection with inhaled agents of bio-terror.

• Began developing a rhesus monkey/influenza A model to study interventions against respiratory pathogens.

• Discovered that nonhuman primate CMV encodes and expresses an interleukin-10-like molecule that binds the cellular IL-10 receptor and has potent immunosuppressive activity.

• Validated the use of an in vitro interferon-gamma assay as an adjunct or alternative to intradermal tuberculin testing for tuberculosis surveillance in nonhuman primates. (Alternatives to Animals in Research)

• Investigated the extent to which ovarian hormones influence mucosal and systemic immunity in female monkeys and women.

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AFFILIATE PROGRAM & OTHER ADVANCES IN MEDICINE AND PRIMATE BIOLOGY

Researchers involved in the CNPRC's Affiliate Program, in collaboration with the CNPRC, have:

• Undertaken an investigation of the efficacy and safety of new treatments for breast cancer, including the antiestrogen tamoxifen, in rhesus monkeys.

• Undertaken the development of an experimental model of diabetes in rhesus monkeys in order to study the impairment of glucagon secretion in response to hypoglycemia.

• Studied cell transplants for diabetics that may one day eliminate the need for insulin injections.

• Worked to elucidate the mechanisms that regulate developmental specificity in the primate visual system.

• Made use of the rhesus monkey model of obesity to examine therapeutic potential in the treatment of obesity and type-2 diabetes.

• Begun cloning nonhuman primate tyrosine phosphatases from insulin sensitive tissue (fat, muscle, and liver) to be used for therapies targeting type-2 diabetes.

• Undertaken an investigation of the organization of binocular, stereo-sensitive cells in the nonhuman primate visual cortex as a prelude to understanding the structural changes that occur from strabismus (“crossed eyes”).

• Demonstrated that sex-linked photopigment polymorphisms in titi monkeys arise from X-linked opsin genes - a unique finding contributing to the evolution of primate color vision.

• Demonstrated that supplementation of infant formula with lactoferrin may protect infants from microbiologic infection by promoting an environment more suitable for growth of “host-friendly” bacteria.

• Accomplished key steps in developing a strategy for successful pancreatic islet transplantation in the rhesus monkey diabetes model, including determining the optimal immunosuppressive drug levels, inducing and managing insulin-dependent diabetes, and successfully transplanting novel templates that will contain the islets.

• Made use of molecular screening methods to monitor genes in rhesus and cynomolgus monkeys to identify natural primate models of human recessive genetic diseases.

• Developed a drug to prevent African River Blindness, a parasitic disease which affects two million people each year.

• Made advances in whole organ transplantation and anti-rejection drugs.

• Researched hormone-like substance that may help heal spinal cord injuries.

• Begun developing gene therapy for cystic fibrosis, an inherited lung disease that is almost always fatal by age 30.

• Characterized and treated spontaneous colitis and diarrhea in nonhuman primates as a potential model for inflammatory bowel disease/ulcerative colitis in humans.

• Established the Helicobacter pylori gastritis model in the rhesus macaque to facilitate the treatment and prevention of this human disease, which is associated with gastric ulcers and neoplasia.

• Developed new vaccines for Lyme disease.

• Conducted research on a geriatric colony of rhesus monkeys (19 years of age and older) as part of a National Institutes of Aging set-aside colony program for research studies on learning/memory, functional imaging of the brain, perimenopausal hormone profiles, gene therapy, cancer, age-related macular degeneration, and osteoporosis.

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