Maternal Subclinical Hypothyroidism Impairs Neurodevelopment in Rat Offspring by Inhibiting the CREB Signaling Pathway.

Abstract

Thyroid hormone is indispensable for fetal brain development, and maternal thyroid hormone deficiency is thought to result in severe and irreversible brain impairments in learning and memory. Epidemiological and animal studies by our group had shown that maternal subclinical hypothyroidism had significant negative impact on neurodevelopment. But, the underlying mechanisms responsible for these neurological alterations remain unclear. In the present study, we performed thyroidectomy and injected L-T4 daily in Wistar rats to induce maternal subclinical hypothyroidism. Our data indicated that the pups from subclinical group showed prolonged latencies during the learning process in the Morris water maze as compared to the control group. Transcription factor cAMP response element-binding protein (CREB) signaling pathway is closely associated with synaptic plasticity, learning, and memory. Consistent with behavioral results, Western blotting also showed decreased activation of three important upstream modulators of CREB signaling pathway: phospho-mitogen-activated protein kinases (P-ERK1/2), phospho-calcium-dependent-calmodulin kinase IV (P-CaMKIV), phospho-serine/threonine protein kinase AKT(P-AKT), as well as total CREB and phospho-CREB as compared to the control at postnatal day 7 (PND 7) in hippocampus. Our findings suggested that decreased activation of the CREB signaling pathway in pups was related to impairments of cognitive function caused by maternal subclinical hypothyroidism.

• Authors: Yuanyuan Zhang, Yuxin Fan, Xiaohui Yu, Xinyi Wang, Suqing Bao, Jiashu Li, Chenling Fan, Zhongyan Shan, Weiping Teng
• Journal: Molecular neurobiology (Mol Neurobiol) Vol. 52 Issue 1 Pg. 432-41 (Aug 2015) ISSN: 1559-1182 [Electronic] United States
• PMID: 25193019 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Cyclic AMP Response Element-Binding Protein
• Thyroid Hormones
• Proto-Oncogene Proteins c-akt
• Calcium-Calmodulin-Dependent Protein Kinase Type 4
• Camk4 protein, rat
• Extracellular Signal-Regulated MAP Kinases

Topics

• Animals
• Animals, Newborn
• Calcium-Calmodulin-Dependent Protein Kinase Type 4 (metabolism)
• Cyclic AMP Response Element-Binding Protein (metabolism)
• Down-Regulation
• Extracellular Signal-Regulated MAP Kinases (metabolism)
• Female
• Hippocampus (metabolism, pathology)
• Hypothyroidism (blood, metabolism)
• Long-Term Potentiation
• Nervous System (growth & development, metabolism, pathology)
• Phosphorylation
• Proto-Oncogene Proteins c-akt (metabolism)
• Rats, Wistar
• Signal Transduction
• Spatial Learning
• Thyroid Hormones (blood)