1995 — 1997 |
Angleson, Joseph K |
F32Activity Code Description: To provide postdoctoral research training to individuals to broaden their scientific background and extend their potential for research in specified health-related areas. |
Exocytosis and Vesicle Recycling in Photoreceptors @ University of Colorado Denver |
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1999 — 2003 |
Angleson, Joseph K |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Exocytosis &Membrane Trafficking in Neuroendocrine Cell
The long term objective of this proposal is to understand the cellular mechanisms of sustained secretion in neuroendocrine cells. Using a combination of new imaging, electrophysiological, and molecular biological techniques, different aspects of the secretion cycle in pancreatic beta-cells will be examined. In particular, single secretory granules and single secretory endosomes will be separately identified and tracked in living cells under a variety of conditions. Specifically, the aims are to test the following hypotheses: (1) Trafficking of secretory granules and secretory-derived endosomes is regulated by cytoplasmic Ca2+ and protein phosphorylation-signals which themselves are generated by cell stimulation from neuronal and hormonal inputs. (2) The readily releasable pool of secretory granules is replenished from predocked granules, without the need for mobilization of granules from the cytoplasm. Sustained secretion, however, requires movement of granules from deep in the cell interior to the plasma membrane. (3) Secretory granules are directly retrieved during endocytosis, and can be recycled to the releasable pool for subsequent exocytosis. Single secretory granules will be identified because they are labeled with a granule specific green fluorescent protein chimera. Single endosomes derived from secretory granules that undergo exo-endocytosis will be additionally labeled with styryl dyes FM1-43 and FM4-64. These optical assays of membrane trafficking in living cells will be combined with patch clamp recording of membrane capacitance and electron microscopy to establish a firm physiological understanding of the mechanisms that allow for sustained secretion from neuroendocrine cells. These studies will lay the ground work for an understanding of how these processes may be altered in diseases of neuroendocrine cells such as diabetes mellitus that demonstrate an apparent disregulation of secretory granule biogenesis, trafficking or recycling.
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2004 — 2008 |
Dores, Robert (co-PI) [⬀] Danielson, Phillip [⬀] Brennan, Miles (co-PI) [⬀] Angleson, Joseph Coughlan, Christina |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Aquisition of a Protein Fractionation System For Research and Education
A grant has been awarded to the University of Denver under the direction of Dr. Phillip Danielson for partial support of the purchase of a Protein Fractionation System. The accurate fractionation, quantization, recovery and characterization of individual proteins from complex proteomes are capabilities that are increasingly essential to the growth and success of biological research and education. Until recently, the analysis of whole proteomes has been heavily dependent on 2-Dimensional Gel Electrophoresis (2DGE)-based approaches. This approach required the laborious screening of hundreds to thousands of resolved "spots" on thin gels. The identification of even a small number of proteins of interest, can require weeks to months to complete. These more traditional methods have several critical shortcomings. 2DGE provides poor resolution of the small peptide hormones and larger membrane-associated proteins that are the focus of many of researchers programs. Furthermore, 2DGE yields results that are often difficult to quantify or reproduce. The Protein Fractionation System provides a cost-effective solution to the traditional limitations of 2DGE-based proteomic research. Test data from difficult samples have confirmed the performance and applicability of the system for our research needs.
Specific research programs that will benefit immediately include NSF-funded studies of the posttranslational processing and modification of neuropeptide hormones involved in the management of reproductive stress and proteomic research aimed at elucidating the underlying neuroendocrine mechanisms of mammalian feeding behavior. Other studies are examining the molecular neurobiology of mammalian taste cells, the recycling of neuroendocrine secretory vesicles and the degradation of misfolded proteins. Finally the Protein Fractionation system will advance collaborative research in molecular ecology and conservation biology conducted in collaboration with the Denver Botanical Gardens. Beyond the benefit to basic research at the University of Denver, a broad range of laboratory and classroom-oriented educational goals will be advanced at both the undergraduate and graduate levels. Benefits will be particularly evident in the molecular-oriented laboratory courses that are at the heart of the Bachelor of Science and Bachelor of Arts degrees in Molecular Biology.
On a broader level, department-sponsored biotechnology classes offered to high school students and teacher-training workshops that promote hands-on science education at the secondary school level will also be greatly enhanced by providing first-hand experience in one of the most modern methods of proteomic analysis. The benefit to high school outreach efforts will be immeasurable given that these programs target students in urban and low-income school districts who have traditionally been underrepresented in the natural sciences. Most importantly, exposing pre-college students to modern technologies will have a significant and positive impact on student excitement about science as a career.
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0.915 |
2010 |
Angleson, Joseph K |
R15Activity Code Description: Supports small-scale research projects at educational institutions that provide baccalaureate or advanced degrees for a significant number of the Nation’s research scientists but that have not been major recipients of NIH support. The goals of the program are to (1) support meritorious research, (2) expose students to research, and (3) strengthen the research environment of the institution. Awards provide limited Direct Costs, plus applicable F&A costs, for periods not to exceed 36 months. This activity code uses multi-year funding authority; however, OER approval is NOT needed prior to an IC using this activity code. |
Regulation of Glucagon Secretion by Melanocortin Receptor-4 @ University of Denver (Colorado Seminary)
DESCRIPTION (provided by applicant): Maintenance of healthy blood sugar is primarily dependent upon the opposing actions of the pancreatic hormones insulin, released from [unreadable]-cells, and glucagon, released from a-cells. Secretion of glucagon from a-cells plays an essential role in countering hypoglycemia. The proposed studies are directed at understanding the regulation of a-cell function required to control glucagon secretion during hypoglycemia. Recent studies have pointed to an essential role for the melanocortin aMSH in this process. Deletion of the POMC gene in mice resulted in severe impairment of the counter- regulatory response to insulin-induced hypoglycemia due to lack of glucagon secretion. This phenotype was rescued by peripheral injection of the POMC gene product, aMSH. Preliminary studies indicate that pancreatic a-cells express an aMSH receptor, melanocortin receptor-4 (MC4R), and that a-cells display functional response to aMSH including change in intracellular [Ca2+] and glucagon secretion. The proposed study will test the hypothesis that MC4R plays a key role in the control of glucagon secretion by regulating [Ca2+]i and exocytic activity of a-cells. The studies are directed at testing this hypothesis in cultured a-cells and islets in vitro and mouse models in vivo. The studies are organized into 2 major Specific Aims. 1. Test the hypothesis that MC4R controls a-cell signaling and glucagon secretion in vitro: cAMP signaling, [Ca2+]i dynamics and glucagon secretion in cultured a-cells &islets. 2. Test the hypothesis that MC4R expressed in pancreatic a-cells is required for the counter regulatory response to hypoglycemia in vivo. This will be conducted with MC4R null mice and mice expressing MC4R only in the pancreatic a-cell. Successful completion of the studies will determine the ability of a-MSH-MC4R to control glucagon secretion and will also address potential interaction of aMSH derived signals with other cellular factors (e.g. direct glucose regulation, paracrine factors) implicated in control of glucagon secretion. This analysis of a newly described mechanism for control of a-cell secretion may point the way toward a therapeutic target for control of insulin-induced hypoglycemia and maintenance of euglycemia. This project will also allow for outstanding biomedical research experience for both undergraduates and MS students in line with the AREA-grant program objectives. PUBLIC HEALTH RELEVANCE: Hypoglycemia can be a serious complication of diabetes and can represent an impediment to intensive insulin therapy. The body's normal response to hypoglycemia is critically dependent upon the release of the hormone glucagon from pancreatic alpha cells, yet the mechanisms of alpha cell control are not well understood. The proposed studies seek to identify a major point of control of alpha cell function.
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