Nitric Oxide (NO) is an essential signaling molecule for diverse physiological and disease processes. While the regulation of NO flux has focused primarily on the study of the three NO synthases (NOS), their respective genetic deficiencies exhibit relatively modest phenotypes. This has led to difficulties in dissecting the specific cellular contributions to NO in different disease processes. In contrast, the hypothesized intracellular compartmentalized availability of arginine substrate in specifying NO flux may explain the "arginine paradox." In humans, the natural history of urea cycle disorders and specifically of argininosuccinic aciduria (ASA) caused by deficiency of argininosuccinic acid lyase (ASL) shows systemic and chronic features that may reflect global dysregulation of NO homeostasis. We propose that ASL is in fact the central regulator of NO homeostasis because it is essential for both the intracellular production of arginine and the utilization of extracellular arginine. In preliminary data, we identify a distinct subcellular and biochemical compartment where local cellular arginine production and channeling by ASL regulates systemic NO production. We have generated a conditional genetic model of Asl deficiency that will allow us to study the consequences of cell autonomous loss of NO in brain (neurons vs. glial cells), the cardiovascular system (endothelial vs. smooth muscle cells), and the pancreatic beta cell with broad implications on understanding the contribution of NO to models of neurodegeneration, cardiovascular disease, and metabolic syndrome. On a biochemical level, we will assess how ASL controls arginine availability for NO production. Our studies may identify novel and more effective strategies for manipulation NO in multi-system disease.

Public Health Relevance

Nitric oxide (NO) is an important molecule in the cause of almost all human diseases. We propose to study a new way on how NO is produced in the body. A chemical called argininosuccinate lyase (ASL) is used to produce arginine which is required for NO production. We will determine whether inhibiting ASL may be the most effective way for controlling NO production in diseases affecting the brain, heart, and pancreas.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM090310-04
Application #
8326710
Study Section
Special Emphasis Panel (ZRG1-BCMB-A (51))
Program Officer
Anderson, Vernon
Project Start
2009-09-30
Project End
2014-08-31
Budget Start
2012-09-01
Budget End
2013-08-31
Support Year
4
Fiscal Year
2012
Total Cost
$372,684
Indirect Cost
$78,654
Name
Baylor College of Medicine
Department
Genetics
Type
Schools of Medicine
DUNS #
051113330
City
Houston
State
TX
Country
United States
Zip Code
77030
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Nagamani, Sandesh C S; Campeau, Philippe M; Shchelochkov, Oleg A et al. (2012) Nitric-oxide supplementation for treatment of long-term complications in argininosuccinic aciduria. Am J Hum Genet 90:836-46
Erez, Ayelet; Nagamani, Sandesh C S; Shchelochkov, Oleg A et al. (2011) Requirement of argininosuccinate lyase for systemic nitric oxide production. Nat Med 17:1619-26
Erez, Ayelet; Nagamani, Sandesh C Sreenath; Lee, Brendan (2011) Argininosuccinate lyase deficiency-argininosuccinic aciduria and beyond. Am J Med Genet C Semin Med Genet 157:45-53
Erez, Ayelet; Shchelochkov, Oleg A; Plon, Sharon E et al. (2011) Insights into the pathogenesis and treatment of cancer from inborn errors of metabolism. Am J Hum Genet 88:402-21