Thyroid hormone and astrocyte morphogenesis

Abstract

Astrocyte cells clearly play a role in neural development, but nowadays their total action is seen as a far wider one. Recent findings consider them as stem cells, involved in the control of most facets of functional neural networks. Astrocytes play a central role in thyroid hormone metabolism in the brain, being the principal transporters of thyroxine from the blood, responsible for its conversion to 3,5,3 -triiodothyronine and hence supplying the neural tissues with the biologically active form of the hormone. Specific thyroid hormone transporters play an essential role in this regulatory system. The presence of thyroid hormone receptors has been demonstrated in cultured astrocytes. Furthermore, thyroid hormone regulates several aspects of astrocyte differentiation and maturation, including the production of extracellular matrix proteins and growth factors, and thus controls neuronal growth and neuritogenesis. Therefore, astrocytes are currently suggested as important mediators of thyroid hormone in neuronal development.

Cellular approaches to central nervous system remyelination stimulation: thyroid hormone to promote myelin repair via endogenous stem and precursor cells

“…Finally, astrocytes, which are critical players in the complex scenario of inflammatory/demyelinating disease, are the cells that produce T 3 in the CNS and, at the same time, provide a target for T 3 action. TH regulates several aspects of astrocyte differentiation and maturation, including the production of extracellular matrix proteins and growth factors, and thus controls neuronal growth and neuritogenesis (Trentin 2006). T 3 alters the expression and organization of several extracellular matrix proteins including laminin, fibronectin and syndecan, which are produced by astrocytes (Mendes-de-Aguiar et al 2008).…”

Hepatic stellate cells and astrocytes

“…65 Interestingly, thyroid hormone regulates several aspects of astrocyte differentiation and maturation, including the production of ECM proteins and growth factors. 66 The role of p75 NTR in liver regeneration was also confirmed in the chloride tetracarbon model of liver cirrhosis. 67 In this study, the involvement of p75 NTR in the regenerative response was attributed to regulation of hepatic myofibroblast apoptosis and proliferation by p75 NTR .…”

Thyroid Hormone Actions on Glioma Cells

“…Thyroid hormones are major physiological regulators of mammalian brain development [2]. Cell differentiation, cell migration, and gene expression are altered as a consequence of thyroid hormone deficiency or excess.…”

“…The actions of thyroid hormone on glial cells in the brain have been reviewed recently [1][2][3]. Among these actions are morphological differentiation [4], modulation of the state of actin in the astrocyte [5], heightening of the antioxidative capacity of astrocytes [6], and secretion of growth factors such as fibroblast growth factor 2 (FGF2; basic fibroblast growth factor (bFGF)) [7].…”