Abstract Details

Title Searching for Efficient Therapeutic Avenues To Treat Adult Polyglucosan Body Disease (APBD) and Lafora Disease (LD) Using a High-Throughput Screening Platform

Topic Movement Disorders

Presentation(s) P03 - (-)

Poster/Presentation
Number 053

Objective

Background BACKGROUND: Polyglucosans are poorly branched polysaccharides formed by excessive glycogen elongation at the expense of its branching. Polyglucosans tend to aggregate into presumably pathogenic, non membrane-bound, large (> 1[micro]m) fibrous structures called PB. PB are found in neurometabolic disorders such as APBD and Lafora Disease (LD), respectively characterized by deficient glycogen branching enzyme (GBE) and excessive glycogen synthase (GS) activities. These disorders are currently incurable.

Design/Methods DESIGN/METHODS: Neuronal and mouse models of APBD were generated by suppressing GBE expression using GBE short-helical-RNA-lentivirus transduction and GBEY329S knockin, respectively. GBE, the autophagy marker LC3 and PB levels were assessed by immunoblotting and indirect immunofluorescence. GBE and GS activities were assessed by 14C-glucose incorporation into glycogen. Apoptosis and autophagy were assessed by flow cytometry and transmission electron microscopy, respectively. Small molecules, computationally designed peptides, and triple-helix-forming-oligos (TFO) targeting GS are tested by high throughput screening (HTS) for their ability to reduce PB accumulation, using Periodic Acid Schiff (PAS) staining. APBD-patient-derived skin fibroblasts and brain cultures from APBD mouse models are used for the HTS.

Results RESULTS: GBE-suppressed neurons were apoptotic and showed PB accumulation, similar to APBD patient-derived cells. Inducers of autophagy cleared PB and reversed their damage, but did so via inhibition of GS activity, rather than PB engulfment in autophagosomes.

Conclusions CONCLUSIONS: Our result that autophagy inducers clear PB and reverse their damage by inhibiting GS suggests a strategy for treating APBD and LD via lowering the ratio between glycogen synthesis and branching in order to reduce the levels of neurotoxic PB. This strategy is currently implemented in HTS-based search for GS inhibitors (small molecules, TFO, peptides), GBE stabilizers (small molecules, peptides), or drugs promoting PB degradation.

Authors/Disclosures
Or Kakhlon, PhD (Hadassah-Hebrew University Medical Center) PRESENTER	Or Kakhlon, PhD has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Golden Heart Flower. Or Kakhlon, PhD has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Golden Heart Flower.
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
Berge A. Minassian, MD (Univeristy of Texas Southwestern Medical Center)	Dr. Minassian has nothing to disclose.
	No disclosure on file
	No disclosure on file
	No disclosure on file
David H. Margolin, MD, PhD (Genzyme Corporation)	Dr. Margolin has received personal compensation for serving as an employee of uniQure, Inc.. Dr. Margolin has stock in Cerevance, Inc. Dr. Margolin has stock in Datacubed Health. Dr. Margolin has stock in uniQure, Inc.. Dr. Margolin has received intellectual property interests from a discovery or technology relating to health care.
	No disclosure on file
	No disclosure on file
	No disclosure on file
Alexander Lossos, MD (Hadassah Hospital)	Dr. Lossos has nothing to disclose.

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