Wirth, E.K.* ; Roth, S.* ; Blechschmidt, C.* ; Hölter, S.M. ; Becker, L. ; Rácz, I. ; Zimmer, A.* ; Klopstock, T.* ; Gailus-Durner, V. ; Fuchs, H. ; Wurst, W. ; Naumann, T.* ; Bräuer, A.* ; Hrabě de Angelis, M. ; Köhrle, J.* ; Grüters, A.* ; Schweizer, U.*
Neuronal 3',3,5-triiodothyronine (T₃) uptake and behavioral phenotype of mice deficient in Mct8, the neuronal T₃ transporter mutated in Allan-Herndon-Dudley syndrome.
J. Neurosci. 29, 9439-9449 (2009)
Thyroid hormone transport into cells requires plasma membrane transport proteins. Mutations in one of these, monocarboxylate transporter 8 (MCT8), have been identified as underlying cause for the Allan-Herndon-Dudley syndrome, an X-linked mental retardation in which the patients also present with abnormally high 3 ',3,5-triiodothyronine (T-3) plasma levels. Mice deficient in Mct8 replicate the thyroid hormone abnormalities observed in the human condition. However, no neurological deficits have been described in mice lacking Mct8. Therefore, we subjected Mct8-deficient mice to a comprehensive immunohistochemical, neurological, and behavioral screen. Several behavioral abnormalities were found in the mutants. Interestingly, some of these behavioral changes are compatible with hypothyroidism, whereas others rather indicate hyperthyroidism. We thus hypothesized that neurons exclusively dependent on Mct8 are in a hypothyroid state, whereas neurons expressing other T-3 transporters become hyperthyroid, if they are exposed directly to the high plasma T-3. The majority of T-3 uptake in primary cortical neurons is mediated by Mct8, but pharmacological inhibition suggested functional expression of additional T-3 transporter classes. mRNAs encoding six T-3 transporters, including L-type amino acid transporters (LATs), were coexpressed with Mct8 in isolated neurons. We then demonstrated Lat2 expression in cultured neurons and throughout murine brain development. In contrast, LAT2 is expressed in microglia in the developing human brain during gestation, but not in neurons. We suggest that lack of functional complementation by alternative thyroid hormone transporters in developing human neurons precipitates the devastating neurodevelopmental phenotype in MCT8-deficient patients, whereas Mct8-deficient mouse neurons are functionally complemented by other transporters, for possibly Lat2.
Impact Factor
Scopus SNIP
Web of Science
Times Cited
Scopus
Cited By
Altmetric
Publication type
Article: Journal article
Document type
Scientific Article
Thesis type
Editors
Keywords
blood-brain-barrier; thyroid-hormone transport; organic anion transporter; amino-acid transporter; thyroxine treatment; monocarboxylate transporter-8; psychomotor retardation; cerebral-cortex; primary culture; rat
Keywords plus
Language
english
Publication Year
2009
Prepublished in Year
HGF-reported in Year
2009
ISSN (print) / ISBN
0270-6474
e-ISSN
1529-2401
ISBN
Book Volume Title
Conference Title
Conference Date
Conference Location
Proceedings Title
Quellenangaben
Volume: 29,
Issue: 30,
Pages: 9439-9449
Article Number: ,
Supplement: ,
Series
Publisher
Society for Neuroscience
Publishing Place
Day of Oral Examination
0000-00-00
Advisor
Referee
Examiner
Topic
University
University place
Faculty
Publication date
0000-00-00
Application date
0000-00-00
Patent owner
Further owners
Application country
Patent priority
Reviewing status
Peer reviewed
POF-Topic(s)
30201 - Metabolic Health
30204 - Cell Programming and Repair
Research field(s)
Genetics and Epidemiology
PSP Element(s)
G-500600-003
G-500600-001
G-500500-001
Grants
Copyright
Erfassungsdatum
2009-09-03