Distinct neuropathologic phenotypes after disrupting the chloride transport proteins ClC-6 or ClC-7/Ostm1.
The proteins ClC-6 and ClC-7 are expressed in the endosomal-lysosomal system. Because Clcn6-deficient mice display some features of neuronal ceroid lipofuscinosis (NCL), CLCN6 may be a candidate gene for novel forms of NCL. Using landmarks of disease progression from NCL mouse models as a guide, we examined neuropathologic alterations in the central nervous system of Clcn6(-/-), Clcn7(-/-), andgl mice. gl mice bear a mutation in Ostm1, the β-subunit critical for Clcn7 function. Severely affected Clcn7(-/-) and gl mice have remarkably similar neuropathologic phenotypes, with pronounced reactive changes and neuron loss in the thalamocortical system, similar to findings in early-onset forms of NCL. In contrast, Clcn6(-/-) mice display slowly progressive, milder neuropathologic features with very little thalamic involvement or microglial activation. These findings detail for the first time the markedly different neuropathologic consequences of mutations in these two CLC genes. Clcn7(-/-) and gl mice bear a close resemblance to the progressive neuropathologic phenotypes of early onset forms of NCL, whereas the distinct phenotype of Clcn6-deficient mice suggests that this gene could be a candidate for a later-onset form of mild neurologic dysfunction with some NCL-like features.
Pediatric Storage Disorders Laboratory, Department of Neuroscience, Centre for the Cellular Basis of Behavior, Institute of Psychiatry, King's College London, UK.
Sarah N R
SN
Pressey
Kieran J
KJ
O'Donnell
Tobias
T
Stauber
Jens C
JC
Fuhrmann
Jaana
J
Tyynelä
Thomas J
TJ
Jentsch
Jonathan D
JD
Cooper
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics; D002540:Cerebral Cortex / Q000378:metabolism / Q000473:pathology*; D018118:Chloride Channels / Q000172:deficiency* / Q000235:genetics; D008565:Membrane Proteins / Q000172:deficiency* / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009472:Neuronal Ceroid-Lipofuscinoses / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D010641:Phenotype; D013788:Thalamus / Q000378:metabolism / Q000473:pathology*
D002352:Carrier Proteins; D018118:Chloride Channels; C490800:Clcn6 protein, mouse; C490803:Clcn7 protein, mouse; D008565:Membrane Proteins; C509143:OSTM1 protein, mouse