Lithium chloride corrects weakness and myopathology in a preclinical model of LGMD1D
AR Findlay, R Bengoechea, SK Pittman… - Neurology …, 2019 - AAN Enterprises
Neurology: Genetics, 2019•AAN Enterprises
Objective To understand DNAJB6's function in skeletal muscle and identify therapeutic
targets for limb-girdle muscular dystrophy 1D (LGMD1D). Methods DNAJB6 knockout (KO)
myoblasts were generated with Crispr/cas9 technology, and differentially accumulated
proteins were identified using stable isotope labeling, followed by quantitative mass
spectrometry. Cultured KO myotubes and mouse muscle from DNAJB6b-WT or DNAJB6b-
F93L mice were analyzed using histochemistry, immunohistochemistry, and immunoblot …
targets for limb-girdle muscular dystrophy 1D (LGMD1D). Methods DNAJB6 knockout (KO)
myoblasts were generated with Crispr/cas9 technology, and differentially accumulated
proteins were identified using stable isotope labeling, followed by quantitative mass
spectrometry. Cultured KO myotubes and mouse muscle from DNAJB6b-WT or DNAJB6b-
F93L mice were analyzed using histochemistry, immunohistochemistry, and immunoblot …
Objective
To understand DNAJB6's function in skeletal muscle and identify therapeutic targets for limb-girdle muscular dystrophy 1D (LGMD1D).
Methods
DNAJB6 knockout (KO) myoblasts were generated with Crispr/cas9 technology, and differentially accumulated proteins were identified using stable isotope labeling, followed by quantitative mass spectrometry. Cultured KO myotubes and mouse muscle from DNAJB6b-WT or DNAJB6b-F93L mice were analyzed using histochemistry, immunohistochemistry, and immunoblot. Mouse functional strength measures included forelimb grip strength and inverted wire hang.
Results
DNAJB6 inactivation leads to the accumulation of sarcomeric proteins and hypertrophic myotubes with an enhanced fusion index. The increased fusion in DNAJB6 KO myotubes correlates with diminished glycogen synthase kinase-β (GSK3β) activity. In contrast, LGMD1D mutations in DNAJB6 enhance GSK3β activation and suppress β-catenin and NFAT3c signaling. GSK3β inhibition with lithium chloride improves muscle size and strength in an LGMD1D preclinical mouse model.
Conclusions
Our results suggest that DNAJB6 facilitates protein quality control and negatively regulates myogenic signaling. In addition, LGMD1D-associated DNAJB6 mutations inhibit myogenic signaling through augmented GSK3β activity. GSK3β inhibition with lithium chloride may be a therapeutic option in LGMD1D.
American Academy of Neurology