New fly models with relevance to Multisystem Proteinopathy, ALS, and other valosin containig protein (VCP)-related diseases

"The power of a genetically tractable model organism coupled with well-established in vivo assays and a relatively short life cycle make Drosophila an attractive system to study VCP disease pathogenesis and novel treatment strategies."

Dis Model Mech. 2021 Jun 23:dmm.048603. doi: 10.1242/dmm.048603.

CRISPR/Cas9-engineered Drosophila knock-in models to study VCP diseases.

Wall JM, Basu A, Zunica ERM, Dubuisson OS, Pergola K, Broussard JP, Kirwan JP, Axelrod CL, Johnson AE

Abstract

"Valosin containing protein (VCP) is a hexameric type II AAA ATPase required for several cellular processes including ER-associated degradation, organelle biogenesis, autophagy and membrane fusion. VCP contains three domains: a regulatory N-terminal domain and two ATPase domains (D1 and D2). Mutations in the N-terminal and D1 domains are associated with several degenerative diseases, including Multisystem Proteinopathy (MSP-1) and ALS. However, patients with VCP mutations vary widely in their pathology and clinical penetrance, making it difficult to devise effective treatment strategies. Having a deeper understanding of how each mutation affects VCP function could enhance the prediction of clinical outcomes and design of personalized treatment options. Over-expressing VCP patient mutations in Drosophila has been shown to mimic many pathologies observed in human patients. The power of a genetically tractable model organism coupled with well-established in vivo assays and a relatively short life cycle make Drosophila an attractive system to study VCP disease pathogenesis and novel treatment strategies. Using CRISPR/Cas9, we have generated individual Drosophila knock-in mutants that include nine hereditary VCP disease mutations. We validate that these models display many hallmarks of VCP-mediated degeneration, including progressive decline in mobility, protein aggregate accumulation and defects in lysosomal and mitochondrial function. We also made some novel and unexpected findings, including laminopathies and sex-specific phenotypic differences in several mutants. Taken together, the Drosophila VCP disease models we have generated in this study will be useful for studying the etiology of individual VCP patient mutations and for testing potential genetic and/or pharmacological therapies."

DOI: 10.1242/dmm.048603
PMID: 34160014

Fly model leads to new model for cellular mechanisms underlying diseases associated with disruption of Valosin-Containing Proteins

Nat Commun. 2021 Jan 21;12(1):513. doi: 10.1038/s41467-020-20796-8.

SVIP is a molecular determinant of lysosomal dynamic stability, neurodegeneration and lifespan.

Johnson AE, Orr BO, Fetter RD, Moughamian AJ, Primeaux LA,
Geier EG, Yokoyama JS, Miller BL, Davis GW
 

From the abstract:

Missense mutations in Valosin-Containing Protein (VCP) are linked to diverse degenerative diseases including IBMPFD, amyotrophic lateral sclerosis (ALS), muscular dystrophy and Parkinson's disease. Here, we characterize a VCP-binding co-factor (SVIP) that specifically recruits VCP to lysosomes. ... We also establish multiple links between SVIP and VCP-dependent disease in our Drosophila model system. ... Finally, we identify a human SVIP mutation and confirm the pathogenicity of this mutation in our Drosophila model. We propose a model for VCP disease based on the differential, co-factor-dependent recruitment of VCP to intracellular organelles.

DOI: 10.1038/s41467-020-20796-8
PMID: 33479240

Wondering what's IBMPFD? Answer: Inclusion body myopathy with early-onset Paget disease and frontotemporal dementia.