ABSTRACT
The proper organized expression of specific genes in time and space is responsible for the organogenesis of the central nervous system including the cerebellum. The epigenetic regulation of gene expression is tightly regulated by an intrinsic intracellular genetic program, local stimuli such as synaptic inputs and trophic factors, and peripheral stimuli from outside of the brain including hormones. Some hormone receptors are expressed in the cerebellum. Thyroid hormones (THs), among numerous circulating hormones, are well-known major regulators of cerebellar development. In both rodents and human, hypothyroidism during the postnatal developmental period results in abnormal morphogenesis or altered function. THs bind to the thyroid hormone receptors (TRs) in the nuclei and with the help of transcriptional cofactors regulate the transcription of target genes. Gene regulation by TR induces cell proliferation, migration, and differentiation, which are necessary for brain development and plasticity. Thus, the lack of TH action mediators may directly cause aberrant cerebellar development. Various kinds of animal models have been established in a bid to study the mechanism of TH action in the cerebellum. Interestingly, the phenotypes differ greatly depending on the models. Herein we summarize the actions of TH and TR particularly in the developing cerebellum.
ABSTRACT
The proper organized expression of specific genes in time and space is responsible for the organogenesis of the central nervous system including the cerebellum. The epigenetic regulation of gene expression is tightly regulated by an intrinsic intracellular genetic program, local stimuli such as synaptic inputs and trophic factors, and peripheral stimuli from outside of the brain including hormones. Some hormone receptors are expressed in the cerebellum. Thyroid hormones (THs), among numerous circulating hormones, are well-known major regulators of cerebellar development. In both rodents and human, hypothyroidism during the postnatal developmental period results in abnormal morphogenesis or altered function. THs bind to the thyroid hormone receptors (TRs) in the nuclei and with the help of transcriptional cofactors regulate the transcription of target genes. Gene regulation by TR induces cell proliferation, migration, and differentiation, which are necessary for brain development and plasticity. Thus, the lack of TH action mediators may directly cause aberrant cerebellar development. Various kinds of animal models have been established in a bid to study the mechanism of TH action in the cerebellum. Interestingly, the phenotypes differ greatly depending on the models. Herein we summarize the actions of TH and TR particularly in the developing cerebellum.
ABSTRACT
A system for Physiology Educator Accreditation was established by the Physiological Society of Japan in 2013 and then implemented. The accreditation process starts by the applicant participating in the education program during the society’s annual meeting, after which the applicant’s teaching and research experiences are reviewed. The education program consists of model lectures to learn teaching skills and lectures to obtain up-to-date knowledge about physiology. The main purpose of the system is to provide an opportunity to obtain a wide range of knowledge and skills for physiology teaching for teachers working at medical universities and universities of life sciences and for young researchers aiming for a tenure-track academic position.
ABSTRACT
Polybrominated diphenylethers (PBDEs) are synthesized chemicals essential to minimize accidents and deaths resulting from fire-outbreaks. Despite their usefulness, public health concern is on the increase over their use. PBDE is global in use, persistent in the environment, and possess the ability to bio-accumulate. Previous studies have suggested that they may interfere with thyroid hormone homeostasis, and are neurotoxic. We therefore investigated the effects of DE71 (a PBDE mixture) on thyroid hormone (TH)-mediated developments in the cerebellum. Employing primary cerebellar culture from new born rats, our study revealed that low dose DE71 significantly suppressed TH-mediated Purkinje cell dendrite arborization. Also, low dose DE71 remarkably impaired neurite extension of granule cells obtained from reaggregate culture of new born rat cerebella. Taken together, our study clearly reveals that DE71 can impair TH-mediated neuronal development in the cerebellum and may therefore interfere with normal TH-induced brain growth and function.
