Substrate reduction therapy for Krabbe disease and a new murine model for cell-autonomous expression of lysosomal hydrolases

Author

Christina Ruth Mikulka, Washington University in St. LouisFollow

ORCID

http://orcid.org/0000-0002-8219-5416

Date of Award

Summer 8-15-2019

Author's School

Graduate School of Arts and Sciences

Author's Department

Biology & Biomedical Sciences (Molecular Genetics & Genomics)

Degree Name

Doctor of Philosophy (PhD)

Degree Type

Dissertation

Abstract

Lysosomal storage diseases (LSDs) are typically caused by a deficiency in a soluble acid hydrolase and are characterized by the accumulation of undegraded substrate in the lysosome. There has been minimal success in developing a therapy to treat Krabbe disease, a lysosomal storage disease caused by the deficiency of galactocerebrosidase (GALC) activity. Here we test a novel substrate reduction therapy (SRT) compound, a competitive inhibitor of UDP-galactose:ceramide galactosyltransferase (CGT), both as a single modality therapy and in combination with BMT or AAV-directed gene therapy in the murine model of Krabbe disease (Twitcher). Although progress has been made towards developing effective therapies for LSDs, determining the role of specific cell types in the pathogenesis of LSDs would undoubtedly uncover additional therapeutic targets. However, this has been a major challenge due to the secretion and subsequent uptake of lysosomal hydrolases by adjacent cells, often referred to a ‘cross-correction’. Here we create and validate a mouse model for cell-autonomous expression of GALC. We show that lysosomal membrane-tethered GALC (GALCLAMP1) retains enzyme activity, is able to cleave galactosylsphingosine, and is unable to cross-correct. Ubiquitous expression of GALCLAMP1 fully rescues the Twitcher mouse, and widespread deletion of GALCLAMP1 recapitulates the Twitcher phenotype. We demonstrate the utility of this model by deleting GALCLAMP1 specifically in myelinating Schwann cells in order to characterize the peripheral neuropathy seen in Krabbe disease.

Language

English (en)

Chair and Committee

Mark S. Sands

Committee Members

Daniel Ory, Stuart Kornfeld, Abhinav Diwan, Jonathan Cooper,

Comments

Permanent URL: https://doi.org/10.7936/er8q-mx75

Recommended Citation

Mikulka, Christina Ruth, "Substrate reduction therapy for Krabbe disease and a new murine model for cell-autonomous expression of lysosomal hydrolases" (2019). Arts & Sciences Electronic Theses and Dissertations. 1931.
https://openscholarship.wustl.edu/art_sci_etds/1931