TY - JOUR
T1 - Macroautophagy is defective in mucolipin-1-deficient mouse neurons
AU - Curcio-Morelli, Cyntia
AU - Charles, Florie A.
AU - Micsenyi, Matthew C.
AU - Cao, Yi
AU - Venugopal, Bhuvarahamurthy
AU - Browning, Marsha F.
AU - Dobrenis, Kostantin
AU - Cotman, Susan L.
AU - Walkley, Steven U.
AU - Slaugenhaupt, Susan A.
N1 - Funding Information:
This work was supported by the National Institutes of Health [ NS39995 to S.A.S., HD045561 to S.U.W., GM007748-31 to C.C.-M.]; the Mucolipidosis Type 4 Foundation [C.C.-M.]; and by the Executive Committee on Research, Massachusetts General Hospital [C.C.-M.].
PY - 2010/11
Y1 - 2010/11
N2 - Mucolipidosis type IV is a neurodegenerative lysosomal disease clinically characterized by psychomotor retardation, visual impairment, and achlorhydria. In this study we report the development of a neuronal cell model generated from cerebrum of Mcoln1-/- embryos. Prior functional characterization of MLIV cells has been limited to fibroblast cultures gleaned from patients. The current availability of the mucolipin-1 knockout mouse model Mcoln1-/- allows the study of mucolipin-1-defective neurons, which is important since the disease is characterized by severe neurological impairment. Electron microscopy studies reveal significant membranous intracytoplasmic storage bodies, which correlate with the storage morphology observed in cerebral cortex of Mcoln1-/- P7 pups and E17 embryos. The Mcoln1-/- neuronal cultures show an increase in size of LysoTracker and Lamp1 positive vesicles. Using this neuronal model system, we show that macroautophagy is defective in mucolipin-1-deficient neurons and that LC3-II levels are significantly elevated. Treatment with rapamycin plus protease inhibitors did not increase levels of LC3-II in Mcoln1-/- neuronal cultures, indicating that the lack of mucolipin-1 affects LC3-II clearance. P62/SQSTM1 and ubiquitin levels were also increased in Mcoln1-/- neuronal cultures, suggesting an accumulation of protein aggregates and a defect in macroautophagy which could help explain the neurodegeneration observed in MLIV. This study describes, for the first time, a defect in macroautophagy in mucolipin-1-deficient neurons, which corroborates recent findings in MLIV fibroblasts and provides new insight into the neuronal pathogenesis of this disease.
AB - Mucolipidosis type IV is a neurodegenerative lysosomal disease clinically characterized by psychomotor retardation, visual impairment, and achlorhydria. In this study we report the development of a neuronal cell model generated from cerebrum of Mcoln1-/- embryos. Prior functional characterization of MLIV cells has been limited to fibroblast cultures gleaned from patients. The current availability of the mucolipin-1 knockout mouse model Mcoln1-/- allows the study of mucolipin-1-defective neurons, which is important since the disease is characterized by severe neurological impairment. Electron microscopy studies reveal significant membranous intracytoplasmic storage bodies, which correlate with the storage morphology observed in cerebral cortex of Mcoln1-/- P7 pups and E17 embryos. The Mcoln1-/- neuronal cultures show an increase in size of LysoTracker and Lamp1 positive vesicles. Using this neuronal model system, we show that macroautophagy is defective in mucolipin-1-deficient neurons and that LC3-II levels are significantly elevated. Treatment with rapamycin plus protease inhibitors did not increase levels of LC3-II in Mcoln1-/- neuronal cultures, indicating that the lack of mucolipin-1 affects LC3-II clearance. P62/SQSTM1 and ubiquitin levels were also increased in Mcoln1-/- neuronal cultures, suggesting an accumulation of protein aggregates and a defect in macroautophagy which could help explain the neurodegeneration observed in MLIV. This study describes, for the first time, a defect in macroautophagy in mucolipin-1-deficient neurons, which corroborates recent findings in MLIV fibroblasts and provides new insight into the neuronal pathogenesis of this disease.
KW - Lysosomal disease
KW - Macroautophagy
KW - Mucolipidosis type IV
KW - Mucolipin 1
KW - Neuronal storage
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U2 - 10.1016/j.nbd.2010.06.010
DO - 10.1016/j.nbd.2010.06.010
M3 - Article
C2 - 20600908
AN - SCOPUS:79955075253
SN - 0969-9961
VL - 40
SP - 370
EP - 377
JO - Neurobiology of Disease
JF - Neurobiology of Disease
IS - 2
ER -