D. Belsham, Ph.D.Contact Information:
|Phone:||(416) 946-7646 (Office)|
|Phone 2:||416-978-8781 (Lab)|
|Address:||Department of Physiology
Medical Sciences Building
Rm. 3344C (office), Rm. 3344 (lab)
1 King's College
University of Toronto
Toronto, ON, M5S 1A8
Degrees: Ph.D. 1992
Brain Research and Integrated Neurophysiology
Endocrine and Diabetes Platform
Reproduction and Development Platform
- Neuronal cell biology, focusing on the mechanisms of neuron-specific gene expression
- Regulation of gonadotropin-releasing hormone gene expression and secretion by gonadal steroid hormones in hypothalamic cell culture
- Regulation of afferent neurons to the GnRH neuron by hormones
- Signal transduction pathways and transcriptional mechanisms involved in the control of neuropeptides involved in energy homeostasis - gene expression and secretion
- Role of nutrients on circadian rhythm proteins in specific peptide-expressing hypothalamic neurons
- Development of clonal, immortalized, hypothalamic neuronal and glial cell lines
- Characterization of novel hypothalamic cell lines developed in my laboratory
My research program currently has three major directions, which are described in more detail below.
Overview of Dr. Belsham’s Research Program:
The main focus of my laboratory is to understand, at the molecular level, how the hypothalamus achieves its diverse physiological functions. The neuroendocrine hypothalamus consists of a complex array of distinct neuronal phenotypes, each expressing a specific complement of neuropeptides, neurotransmitters and receptors. Many of our vital needs, such as those for growth, reproduction, nutrition, sleep, and stress responses, depend on hormonal balance or homeostasis, which is controlled by both external and internal stimuli or signals at the hypothalamic level.
A) Regulation of GnRH Neurons and Afferent Control Mechanisms:
In order to begin to dissect the molecular signals responsible for the release of specific peptides from individual hypothalamic neurons, my laboratory has focussed on the peptide that controls reproduction, gonadotropin-releasing hormone or GnRH. A large number of neuromodulators have been implicated in the control of reproductive function, as they have been found to regulate GnRH synthesis and secretion. My research program studies many aspects of GnRH function, and how afferent neurons affect the GnRH neurons. We also study the direct regulation of these afferent neurons, such as kisspeptin, neuropeptide Y, and gonadotropin inhibitory hormone, by steroids and other peripheral signals.
B) Generation and Characterization of Hypothalamic Cell Models:
We therefore analyze the direct actions of neuromodulators on individual GnRH neurons; the transcriptional mechanisms dictating the neurogenesis of individual hypothalamic neurons; and the development of specific immortalized hypothalamic neuronal cell models in order to understand the molecular mechanisms involved in interneuron communication and signaling. To address this last point, my laboratory has recently generated a number of cell models representing other specific cell types from the hypothalamus. These models have been used by many labs worldwide to understand how hypothalamic neurons function. These models include embryonic- and adult-derived cell models from the mouse and rat, and represent the many cell types found in the hypothalamus and hippocampus.
C) Analysis of the Neuropeptides involved in Energy Homeostasis:
We have a strong track record of neuroendocrine research, and have also expanded our research program to include the study of neuropeptides involved in both reproduction and energy homeostasis. Currently half of my research efforts are directed towards studies related to the function of the GnRH and afferent neurons, such as kisspeptin, neuropeptide Y and gonadotropin inhibitory hormone, and the other half has extended our research program to include studies of many of the neuropeptide-expressing neurons involved in energy homeostasis. These include neuropeptide Y, neurotensin, brain ghrelin, corticotropin-releasing hormone, and proopiomelanocortin. We are currently analyzing the changes in gene expression and signal transduction events after exposure to key peripheral signals such as insulin, ghrelin, glucose, leptin, and estrogen. We also study the mechanisms involved in neuroinflammatory signal transduction induced by exposure of neurons to excess nutrients, such as saturated fatty acids and high glucose. Importantly, there is also a direct relationship between nutritional status and reproduction, therefore my research program is poised to utilize all the information gained to provide insight into the complex nature of integrated neuroendocrine control of basic physiology.
Cell and tissue culture: Brain slice, immortalized neurons, neurons, pancreas cells, pancreatic islets, primary hypothalamic cultures.
Procedures: Elisa, gene expression analysis, immunohistochemistry, immunocytochemistry, in vivo hypothalamus immunocytochemistry, microarrays, molecular and cellular biology techniques, proteomics, qRT-PCR, retroviral and lentiviral transfections, RIA, RT-PCR, signal transduction characterization, siRNA, stereotaxic brain surgery, western blot.
EQUIPMENT USEDAnalytical balances, bacterial shaker and incubator, benchtop centrifuge, blotting apparatus, culture hood, culture incubators, cryostat, Departmental beta and gamma counters, dissecting microscope, fluorescence microscope, fresh tissue sectioning systems, gel apparatus, low- and high-speed centrifuge, low and ultralow freezers, microwave oven, mini vortexer, plate reader, ProBlot hybridization oven, real-time/thermocycler, setups for electropherosis, stirrer/hot plate, water baths.
SAMPLE PUBLICATIONS AND ABSTRACTSClick on link to PubMed
PRESENT TRAINEESLeigh Wellhauser – Post-doctoral Fellow
Prasad Dalvi – Post-doctoral Fellow
PRESENT COLLABORATIONSWithin the Department of Physiology:
Outside the Department of Physiology:
David Lovejoy, Cell and Systems Biology, U of T
Martin Ralph, Psychology/Cell and Systems Biology, U of T
Abhiram Sahu, University of Pittsburg, USA
Debbie Good, Viginia Tech, USA
Rob Fowkes, Univ of London, UK
Charles Mobbs, Mt Sinai Sch of Med, NY, USA
Susanne la Fleur, University of Amsterdam
Serge Luguet, University of Paris
Committee member/Officer of national or international scientific organization:
Council Member representing Canada on the International Neuroendocrine Federation