Locomotor deficiencies and aberrant development of subtype-specific GABAergic interneurons caused by an unliganded thyroid hormone receptor alpha1.
Thyroid hormone (TH) deficiency during development causes severe and permanent neuronal damage, but the primary insult at the tissue level has remained unsolved. We have defined locomotor deficiencies in mice caused by a mutant thyroid hormone receptor alpha1 (TR alpha1) with potent aporeceptor activity attributable to reduced affinity to TH. This allowed identification of distinct functions that required either maternal supply of TH during early embryonic development or sufficient innate levels of hormone during late fetal development. In both instances, continued exposure to high levels of TH after birth and throughout life was needed. The hormonal dependencies correlated with severely delayed appearance of parvalbumin-immunoreactive GABAergic interneurons and increased numbers of calretinin-immunoreactive cells in the neocortex. This resulted in reduced numbers of fast spiking interneurons and defects in cortical network activity. The identification of locomotor deficiencies caused by insufficient supply of TH during fetal/perinatal development and their correlation with subtype-specific interneurons suggest a previously unknown basis for the neuronal consequences of endemic cretinism and untreated congenital hypothyroidism, and specifies TR alpha1 as the receptor isoform mediating these effects.
Wallis
Karin
K
Department of Cell and Molecular Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
Sjögren
Maria
M
van Hogerlinden
Max
M
Silberberg
Gilad
G
Fisahn
André
A
Nordström
Kristina
K
Larsson
Lars
L
Westerblad
Håkan
H
Morreale de Escobar
Gabriela
G
Shupliakov
Oleg
O
Vennström
Björn
B
D000818:Animals; D005260:Female; D047109:Fetal Development / Q000235:genetics; D007395:Interneurons / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D008024:Ligands; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009043:Motor Activity / Q000235:genetics; D019957:Motor Skills Disorders / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D011247:Pregnancy; D037021:Thyroid Hormone Receptors alpha / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D013963:Thyroid Hormones / Q000378:metabolism / Q000502:physiology
D008024:Ligands; D037021:Thyroid Hormone Receptors alpha; D013963:Thyroid Hormones