The objective of the proposed study is to further our understanding of the biochemistry of metachromatic leukodystrophy (MLD). MLD is a group of neurological disorders associated with dysfunctions in the catabolism of cerebroside sulfate (sulfatide). Classic MLD is characterized by progressive demyelination and neuropathy. At least seven different forms of MLD are now recognized and we know that it is not a simple, one gene-one enzyme-one mutation disease. A variety of mutations affecting more than one allelic site can cause dysfunctions of sulfatide catabolism and give rise to clinical MLD. The cerebroside sulfatase hydrolytic system must be viewed as a multi-component system. The amount and type of information needed to understand the biochemistry of MLD has expanded accordingly. Much of this information can be obtained by studying cerebroside sulfate hydrolysis in cultured cells. The present proposal consists of three components. The first phase will emphasize the cell biology of the intact fibroblast sulfatide loading test and characterization of the intracellular sulfatidase reaction. Each component of the system will be characterized with respect to parameters such as cell uptake, subcellular localization, optimal concentrations and in situ interaction with other components. These will serve as a base line for the second phase of the project which will focus on specific dysfunctions of cerebroside sulfate catabolism. Detailed studies will attempt to define the nature of specific lesions at the molecular level. The third component focuses on individual components of the CS metabolic system. Selected properties of highly purified enzyme and CS activator will be studied. Immunochemical techniques will be developed for monitoring synthesis, regulation, and turnover of the enzyme and activator proteins. DNA and RNA progenitors will be isolated, characterized, and their dynamic relationships explored. This information should facilitate accurate diagnosis, help define pathogenesis and contribute to the development of effective therapies.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS011665-17
Application #
3394556
Study Section
Neurology C Study Section (NEUC)
Project Start
1977-08-01
Project End
1992-07-31
Budget Start
1990-08-01
Budget End
1992-07-31
Support Year
17
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of California Los Angeles
Department
Type
Other Domestic Higher Education
DUNS #
119132785
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Fluharty, A L; Lombardo, C; Louis, A et al. (1999) Preparation of the cerebroside sulfate activator (CSAct or saposin B) from human urine. Mol Genet Metab 68:391-403
Stevens, R L; Faull, K F; Conklin, K A et al. (1993) Porcine cerebroside sulfate activator: further structural characterization and disulfide identification. Biochemistry 32:4051-9
Fluharty, A L; Katona, Z; Meek, W E et al. (1992) The cerebroside sulfate activator from pig kidney: purification and molecular structure. Biochem Med Metab Biol 47:66-85
Fluharty, A L; Fluharty, C B; Bohne, W et al. (1991) Two new arylsulfatase A (ARSA) mutations in a juvenile metachromatic leukodystrophy (MLD) patient. Am J Hum Genet 49:1340-50
Louis, A I; Fluharty, A L (1991) Activator-dependent hydrolysis of myelin cerebroside sulfate by arylsulfatase A. Dev Neurosci 13:41-6
Louis, A I; Widen, K E; Tsay, K K et al. (1991) Synthesis and characterization of NBD-PS: a fluorescent analog of cerebroside arylsulfatase A deficiency disorders. Mol Chem Neuropathol 14:113-30
Fluharty, A L (1990) The relationship of the metachromatic leukodystrophies to neuropsychiatric disorders. Mol Chem Neuropathol 13:81-94
Fluharty, A L; Neidengard, L; Holtzman, D et al. (1986) Late-onset Krabbe disease initially diagnosed as cerebroside sulfatase activator deficiency. Metab Brain Dis 1:187-95
Kihara, H; Meek, W E; Fluharty, A L (1986) Attenuated activities and structural alterations of arylsulfatase A in tissues from subjects with pseudo arylsulfatase A deficiency. Hum Genet 74:59-62
Sarafian, T A; Tsay, K K; Jackson, W E et al. (1985) Studies on the charge isomers of arylsulfatase A. Biochem Med 33:372-80

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