Expression of thyroid hormone receptor isoforms in the oligodendrocyte lineage.

Thyroid hormone (T3) regulates brain development and function and in particular ensures normal myelination. Animal models and in vitro systems have been employed to demonstrate the effects of T3, which acts via nuclear hormone receptors. T3 receptors (TRs) are transcription factors that activate or suppress target gene expression, such as myelin basic protein (MBP), in a hormone-dependent or -independent fashion.

Coexpression of thyroid hormone receptor isoforms in mouse oligodendrocytes.

Double and triple immunocytochemistry with stage-specific markers and specific antireceptor antibodies was used to study expression of nuclear thyroid hormone receptor (TR) isoforms in cultured mouse oligodendrocytes. To evaluate the coexpression of each TR isoform, antibodies were raised in rabbits and mice against specific regions of alpha1-TR and alpha2-TR common to both alpha isoforms and beta1-TR. Their specificities were assessed by Western blotting and by immunocytochemistry on rat hepatocytes.

Ontogeny of steroid metabolizing enzymes in rat oligodendrocytes.

Rat oligodendroglial cells were isolated from newborn and developing brains and used immediately after, for quantification of steroid metabolizing activities. Oligodendrocytes (Ol) and their progenitor cells were incubated with [(14)C] testosterone, [(14)C] progesterone, [(14)C] pregnenolone or [(14)C] dehydroepiandrosterone (DHEA). Oligodendrocytes and their progenitor cells expressed different steroid metabolizing enzymes.

Adrenal gland SNAP-25 expression is altered in thyroid hormone receptor knock-out mice.

SNAP-25 is a protein in neurons and neuroendocrine cells, which is involved, together with syntaxin and VAMP, in neurotransmitter release and neurite outgrowth. Since the thyroid hormone receptors TR alpha and TR beta are essential for nervous system development, their possible role in regulating the expression of these vesicle trafficking proteins was examined by analysing SNAP-25 levels in TR alpha and TR beta knock-out mice. Immunoblotting and RT-PCR showed that SNAP-25 levels are increased in the adrenal gland, but not in cerebellum, in knock-out mice, while syntaxin-1 and VAMP-2 are unaffected in either tissue.

Phospholipid composition in late infantile neuronal ceroid lipofuscinosis.

Background: Neuronal ceroid lipofuscinosis (NCL) is a relatively common group of inherited neurodegenerative disorders characterised by the accumulation of autofluorescent lipopigments (ceroid) similar to lipofuscin. Because of this property, studies have concentrated on fatty acid metabolism and lipid peroxidation.

Methods: In the present study, the fatty acid composition of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) and the molecular species compositions of diacylglycerophosphocholine (diacyl GPC), diacylglycerophosphoethanolamine (diacyl GPE) and alkenylacyl GPE (plasmalogens) were investigated in cultured skin fibroblasts from three patients with a confirmed diagnosis of the late infantile form of the disease (LINCL, CLN2) and three healthy age-matched controls.