Immunity has a well-established role in Facioscapulohumeral Muscular Dystrophy (FSHD) muscle pathology, but animal models do not currently exist to investigate these mechanisms. Our project goal is to develop a mouse model of the FSHD innate immune response observed in FSHD muscles by combining muscle and hematopoietic stem cell (HSC) xeno-engraftment into the NSG-QUAD (NOD scid gamma, expressing human SCF, GM-CSF, IL3 and CSF1) mouse, which has significantly enhanced innate immune cell development. Our overriding hypothesis is that sporadic misexpression of the full-length double homeobox 4 (DUX4-fl) FSHD germ line transcription factor in FSHD muscles elicits an innate immunity response to low level muscle damage caused by misexpression of toxic DUX4-fl regulated germline proteins and abnormal proteins produced through downstream inhibition of nonsense mediated decay machinery, leading to an adaptive immune response that destroys immune targeted muscles and allows fat and connective tissue replacement. Our studies utilize immunohistology, blood cytokine and NanoString RNA assays to monitor innate immunity gene expression specifically elicited by FSHD muscle xenografts in mice with a humanized immune system. Once this model is established, the role of DUX4-fl in eliciting the innate immune response will be investigated by DUX4-fl knockdown using the DUX4-fl-specific morpholino, FM10, and the roles of specific cytokines in the FSHD innate immunity response will be investigated using cytokine inhibitors. As there are currently no animal models of immunity in human muscle diseases, this high risk, high reward project promises to provide a new experimental model of FSHD immunity to investigate FSHD muscle pathology and enable development of immune therapeutics.

Public Health Relevance

Immunity has a well-documented role in FSHD muscle pathology, but there are currently n o a n i m a l m o d e l s o f i m m u n i t y i n m u s c l e d i s e a s e . This project u n d e r t a k e s to develop a new muscle/blood humanized mouse model of FSHD innate immunity that will uniquely enable investigations of the role of FSHD disease genes in FSHD muscle pathology and the development of immune therapeutics to treat this devastating disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21NS101257-02
Application #
9616884
Study Section
Skeletal Muscle and Exercise Physiology Study Section (SMEP)
Program Officer
Nuckolls, Glen H
Project Start
2018-01-01
Project End
2019-12-31
Budget Start
2019-01-01
Budget End
2019-12-31
Support Year
2
Fiscal Year
2019
Total Cost
Indirect Cost
Name
University of Massachusetts Medical School Worcester
Department
Neurology
Type
Schools of Medicine
DUNS #
603847393
City
Worcester
State
MA
Country
United States
Zip Code