Title

Thyroid hormone regulates the extracellular organization of laminin on astrocytes

UMMS Affiliation

Molecular Endocrinology Laboratory

Date

10-28-1999

Document Type

Article

Subjects

Animals; Animals, Newborn; Astrocytes; Cells, Cultured; Electrophoresis, Polyacrylamide Gel; Extracellular Matrix; Immunohistochemistry; Immunosorbent Techniques; Laminin; Mice; Microscopy, Fluorescence; Rats; Sarcoma, Experimental; Thyroid Hormones; Thyroxine; Triiodothyronine

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Astrocytes produce laminin, a key extracellular matrix guidance molecule in the developing brain. Laminin is bound to transmembrane receptors on the surface of astrocytes known as integrins, which are, in turn, bound to the microfilament meshwork inside the astrocyte. Previous studies have shown that T4 regulates the pattern of integrin distribution in astrocytes by modulating the organization of the microfilaments. In this study, the effect of thyroid hormone on the secretion and topology of laminin in astrocytes was examined. Linear arrays of secreted laminin were observed on the surface of the T4-treated astrocytes within 10 h after seeding the cells onto poly-D-lysine-coated coverslips and became an organized meshwork by 24 h. In contrast, little if any laminin was identified on the surface of either hormone-deficient or T3-treated cells until 36 h after seeding and then was restricted to punctate deposits. Secretion of laminin into the medium by hormone-deficient and T3-treated cells was significantly greater than that by T4-treated cells. Conversely, deposition of laminin into the extracellular matrix was significantly greater in T4-treated cells than in hormone-deficient and T3-treated cells. Thyroid hormone had no effect on the production of laminin by astrocytes. These data show that T4 regulates the extracellular deposition and organization of laminin on the surface of astrocytes and provide a mechanism by which this morphogenic hormone can influence neuronal migration and axonal projection in the developing brain.

Rights and Permissions

Citation: Endocrinology. 1999 Nov;140(11):5014-21.

Related Resources

Link to Article in PubMed

Journal Title

Endocrinology

PubMed ID

10537126