Adult Mice Lacking Mct8 and Dio2 Proteins Present Alterations in Peripheral Thyroid Hormone Levels and Severe Brain and Motor Skill Impairments

Soledad Bárez-López*, Carmen Grijota-Martínez, Eva Ausó, Mario Fernández-De Frutos, Ana Montero-Pedrazuela, Ana Guadaño-Ferraz

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

39 Citations (Scopus)

Abstract

Background: Mutations in the thyroid hormone (TH) transporter monocarboxylate transporter 8 (MCT8) lead to peripheral hyperthyroidism and profound psychomotor alterations in humans. Mice lacking Mct8 present peripheral hyperthyroidism but no gross neurological abnormalities due to brain compensatory mechanisms involving the enzyme deiodinase type 2 (Dio2). Methods: Here we have analyzed the endocrine and neurologic phenotype of mice lacking both Mct8 and Dio2 at three and six months of age. Thyroxine (T4) and 3,5,3′ triiodothyronine (T3) levels/content were measured by specific radioimmunoassays; motor skill performance was evaluated by the footprint, rotarod, four limb hanging wire, and balance beam tests; and brain histological analysis was performed by immunostaining for neurofilament and parvalbumin. Results: We have found that this mouse model presents peripheral hyperthyroidism and brain hypothyroidism. Interestingly, the severity of the brain hypothyroidism seems permanent and varies across regions, with the striatum being a particularly affected area. We have also found brain alterations at the histological level compatible with TH deficiency and impaired motor skills. Conclusions: These findings indicate the potential of Mct8/Dio2-deficient mice to represent a model for human MCT8 deficiency, to understand the mechanisms underlying its pathophysiology, and ultimately design therapeutic interventions for human patients.

Original languageEnglish
Pages (from-to)1669-1682
Number of pages14
JournalThyroid
Volume29
Issue number11
Early online date23 Sept 2019
DOIs
Publication statusPublished - 14 Nov 2019

Keywords

  • deiodinase type 2
  • histological brain impairments
  • Mct8 deficiency
  • motor skills impairments
  • mouse model

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