TY - JOUR
T1 - Adult Mice Lacking Mct8 and Dio2 Proteins Present Alterations in Peripheral Thyroid Hormone Levels and Severe Brain and Motor Skill Impairments
AU - Bárez-López, Soledad
AU - Grijota-Martínez, Carmen
AU - Ausó, Eva
AU - Fernández-De Frutos, Mario
AU - Montero-Pedrazuela, Ana
AU - Guadaño-Ferraz, Ana
PY - 2019/11/14
Y1 - 2019/11/14
N2 - 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.
AB - 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.
KW - deiodinase type 2
KW - histological brain impairments
KW - Mct8 deficiency
KW - motor skills impairments
KW - mouse model
UR - http://www.scopus.com/inward/record.url?scp=85075227158&partnerID=8YFLogxK
U2 - 10.1089/thy.2019.0068
DO - 10.1089/thy.2019.0068
M3 - Article (Academic Journal)
C2 - 31359845
AN - SCOPUS:85075227158
SN - 1050-7256
VL - 29
SP - 1669
EP - 1682
JO - Thyroid
JF - Thyroid
IS - 11
ER -