Development of a Cellular Dysferlin Deficiency Screening Assay

Grant Duration
07/12 – 09/16

Objective
To develop a cell-based high throughput screening assay using dysferlin deficient cells.

Project Summary
The aim of this project is to develop a simple test for the well-being of a muscle cell in the absence of dysferlin and to use the test to identify compounds (potential drugs) that improve the well-being of dysferlin deficient muscle cells. Since the project was initiated in July 2012, two such tests were developed, and each was used to screen a library of compounds including approved drug and bioactive compounds. The screen identified several hits that might be useful in treating the disease caused dysferlin deficiency, which are currently being characterized. If any of these leads continue to appear promising following characterization, the next likely step will be evaluation of the compound in animal models of dysferlin deficiency.

By Evotec|2021-05-06T20:12:08+00:00October 1st, 2016|Past Projects|0 Comments

About the Author: Evotec

Evotec is a drug discovery alliance and development partnership company focused on rapidly progressing innovative product approaches with leading pharmaceutical and biotechnology companies. They operate worldwide providing the highest quality stand-alone and integrated drug discovery solutions, covering all activities from target-to-clinic. The Company has established a unique position by assembling top-class scientific experts and integrating state-of-the-art technologies as well as substantial experience and expertise in key therapeutic areas including neuroscience, pain, metabolic diseases as well as oncology, inflammation and infectious diseases. Evotec has long-term discovery alliances with partners including Bayer, Boehringer Ingelheim, CHDI, Genentech, Janssen Pharmaceuticals Inc., Medimmune/AstraZeneca, Roche and UCB. In addition, the Company has existing development partnerships and product candidates both in clinical and pre-clinical development. These include partnerships with Boehringer Ingelheim, MedImmune in the field of diabetes, with Janssen Pharmaceuticals in the field of depression and Roche in the field of Alzheimer's disease. For additional information please go to www.evotec.com.

Bla/J mice (B6.A-Dysf^prmd/GeneJ)

Availability:
The Jackson Laboratory
Stock number: 012767
Strain information: http://jaxmice.jax.org/strain/012767.html
Phone: 800-422-MICE (800-422-6423)
610 Main Street, Bar Harbor, Maine 04609 USA

Please note that this strain has been cryopreserved by the Jackson Laboratories, but the Jain Foundation maintains a private colony of these mice for public use. To obtain these mice, please contact the Jain Foundation:

Jain Foundation Inc.
9706 Fourth Ave NE, Suite 101
Seattle, Washington 98115
Phone: 425-882-1492
Fax: 425-882-1050

Email: admin@jain-foundation.org

Development:
In these mice the progressive muscular dystrophy (prmd) allele from the A/J inbred strain is crossed onto the C57BL/6 genetic background. The cross was performed in the laboratory of Dr. Isabelle Richard at Genethon and the backcross generation reached N8. In collaboration with the Jain Foundation, Dr. Richard donated the strain to The Jackson Laboratory in 2010. Upon arrival, mice were bred to C57BL/6J for at least 2 generations to establish the colony.

Mutation:
An ETn retrotransposon (5-6kb) is inserted in intron 4 of the dysferlin gene.

Symptoms:
Disease onset is observed by 2 months and is characterized by the presence of centronucleated fibers and areas of inflammation. As seen with the original background A/J, mice homozygous for the prmd allele on the C57BL/6J background display an increasing number of centronucleated fibers and impairment in the majority of muscles by 4 months of age. In order of severity, the most affected muscles are psoas, quadriceps femoris, tibialis anterior, and gastrocnemius. Mice exhibit a decreased membrane repair capacity following laser wounding experiments. In an open space assay, mice cover less distance and are less active than wild-type. Mice that are homozygous for this allele are viable, fertile and normal in size.

Comparison with other disease strains:
Disease progression is similar to A/J: slightly slower than in SJL/J, Dysf-/- (Campbell), Dysf-/- (Brown), and C57BL/10.SJL mice. As in both SJL/J and Dysf-/- (Brown) mice, proximal muscles are more severely affected than distal muscles. As in Dysf-/- (Brown) mice, abdominal muscles are also affected.

Control strain(s):
C57BL/6 (for homozygotes); littermates (for heterozygotes).

References:
Lostal W; Bartoli M; Bourg N; Roudaut C; Bentaib A; Miyake K; Guerchet N; Fougerousse F; McNeil P; Richard I. 2010. Efficient recovery of dysferlin deficiency by dual adeno-associated vector-mediated gene transfer. Hum Mol Genet 19(10):1897-907.

PMID: 20154340

Below is a quick summary of the inclusion/exclusion criteria. Please review this information carefully prior to making any decision regarding participating.

Inclusion Criteria:

Must be Non-ambulant (cannot walk 10 meters in ≤ 30 sec) and age 18 years or older
Established mutations of the dysferlin gene on both alleles
Impaired muscle function but with sufficient muscle preservation to ensure muscle transfection based on magnetic resonance image of the EDB showing sufficient muscle preservation to permit transfection
Willingness of sexually active subjects with reproductive capacity to practice reliable method of contraception (If appropriate), during the first six months after gene transfer (females) or until two negative sperm samples are obtained post gene transfer (males).

Exclusion Criteria:

Active viral infection based on clinical observations or serological evidence of HIV, or Hepatitis A, B or C infection
The presence of dysferlin mutations without weakness or loss of function
Symptoms or signs of cardiomyopathy, including:
Dyspnea on exertion, pedal edema, shortness of breath upon lying flat, or rales at the base of the lungs
Echocardiogram with ejection fraction below 40%
Diagnosis of (or ongoing treatment for) an autoimmune disease
Persistent leukopenia or leukocytosis (WBC ≤ 3.5 K/µL or ≥ 20.0 K/µL) or an absolute neutrophil count < 1.5K/µL
Concomitant illness or requirement for chronic drug treatment that in the opinion of the PI creates unnecessary risks for gene transfer
Pregnancy
AAVrh74 or AAV8 binding antibody titers > 1:50 as determined by ELISA immunoassay
Abnormal laboratory values in the clinically significant range in the table below, based upon normal values in the Nationwide Children's Hospital Laboratory: GGT, Total Bilirubin, Cystatine, Hemoglobin, White Blood Cells
This first phase of the trial will be small and will only evaluate safety; patients enrolled are not expected to show improvement in their symptoms. If the initial trial is successful, a Phase 2 trial will be scheduled, which will look for efficacy (improvement in symptoms) as well as safety. Each phase would include more patients. So, it is a process and we are pacing ourselves as we support this major milestone in the field of therapeutic intervention for people suffering from dysferlinopathy.