To date, the biological role of growth hormone binding protein (GHBP) remains largely unknown. While many theories have been put forth, there is no direct evidence that can identify a specific role for this protein. We and others believe that it is highly likely that the GHBP plays a significant role in the GH/IGF- 1 axis. The main argument for this is due to the convergent evolution of two distinct mechanisms in mammals to produce the same protein (i.e. in humans the GHBP is produced by proteolytic cleavage of the GH receptor (GHR) extracellular domain while in rodents GHBP is produced by alternative splicing of the GHR precursor mRNA). Thus, we believe that the best way to elucidate the function of the GHBP is to create a GHBP gene specific disrupted or """"""""knockout"""""""" mouse line. Hence, the objective of this research is to create the first GHBP specific gene-disrupted mouse and then to determine the contributions of GHBP on the growth phenotype as well as other metabolic processes in these animals. Our laboratory has already disrupted the mouse GHR/BP genes and generated combined GHR/GHBP """"""""knockout"""""""" mice. In the homozygous state, these mice display a dwarf phenotype and serve as a model for a human GH- insensitive state termed Laron Syndrome. Although these mice are dwarf and obese, they are extremely sensitive to the action of insulin, resistant to diabetic kidney damage and, surprisingly, they have an extended life span. With this animal providing a background, we are now ready to test the specific hypotheses concerning the in vivo importance of GHBP by isolated GHBP gene-deficiency using a targeted gene disruption approach. We are confident that many questions concerning the biological role of GHBP will be answered in addition to new questions being raised once the GHBP gene disrupted mouse is generated. This proposal seeks to elucidate the role of growth hormone binding protein (GHBP), a protein whose function remains largely unknown other than its ability to bind growth hormone (GH) in the blood. Unlike GHBP, the function of GH is well established and GH is known to play an important role in normal metabolism and in the progression of several diseases such as diabetes, cancer and even aging. Thus, results obtained from this proposal would not only further our understanding of GH, but could help further our understanding of complex metabolic conditions and of the processes involved in aging. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Academic Research Enhancement Awards (AREA) (R15)
Project #
1R15DK075436-01A1
Application #
7303768
Study Section
Molecular and Cellular Endocrinology Study Section (MCE)
Program Officer
Malozowski, Saul N
Project Start
2007-09-01
Project End
2010-08-31
Budget Start
2007-09-01
Budget End
2010-08-31
Support Year
1
Fiscal Year
2007
Total Cost
$220,500
Indirect Cost
Name
Ohio University Athens
Department
Other Basic Sciences
Type
Schools of Osteopathy
DUNS #
041077983
City
Athens
State
OH
Country
United States
Zip Code
45701
Sackmann-Sala, Lucila; Berryman, Darlene E; Lubbers, Ellen R et al. (2014) Age-related and depot-specific changes in white adipose tissue of growth hormone receptor-null mice. J Gerontol A Biol Sci Med Sci 69:34-43
Berryman, Darlene E; Lubbers, Ellen R; Magon, Vishakha et al. (2014) A dwarf mouse model with decreased GH/IGF-1 activity that does not experience life-span extension: potential impact of increased adiposity, leptin, and insulin with advancing age. J Gerontol A Biol Sci Med Sci 69:131-41
Martos-Moreno, G A; Sackmann-Sala, L; Berryman, D E et al. (2013) [Anatomical heterogeneity in the proteome of human subcutaneous adipose tissue]. An Pediatr (Barc) 78:140-8
Martos-Moreno, G A; Kopchick, J J; Argente, J (2013) [Adipokines in healthy and obese children]. An Pediatr (Barc) 78:189.e1-189.e15
Ding, Juan; Sackmann-Sala, Lucila; Kopchick, John J (2013) Mouse models of growth hormone action and aging: a proteomic perspective. Proteomics 13:674-85
Burgos-Ramos, Emma; Sackmann-Sala, Lucila; Baquedano, Eva et al. (2012) Central leptin and insulin administration modulates serum cytokine- and lipoprotein-related markers. Metabolism 61:1646-57
Sackmann-Sala, Lucila; Berryman, Darlene E; Munn, Rachel D et al. (2012) Heterogeneity among white adipose tissue depots in male C57BL/6J mice. Obesity (Silver Spring) 20:101-11
Sackmann-Sala, Lucila; Berryman, Darlene E; Lubbers, Ellen R et al. (2012) Decreased insulin sensitivity and increased oxidative damage in wasting adipose tissue depots of wild-type mice. Age (Dordr) 34:1225-37
Liang, Ruqiang; Khanna, Amit; Muthusamy, Senthilkumar et al. (2011) Post-transcriptional regulation of IGF1R by key microRNAs in long-lived mutant mice. Aging Cell 10:1080-8
Martin, Brent T; List, Edward O; Kopchick, John J et al. (2011) Selective inner retinal dysfunction in growth hormone transgenic mice. Growth Horm IGF Res 21:219-27

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