Metallothionein-I+II induction by zinc and copper in primary cultures of rat microglia.
Metallothioneins (MTs) are a family of low molecular weight proteins which in rodents comprise four isoforms (MT-I to -IV). MT-I+II are widely expressed isoforms which are highly inducible by factors such as heavy metals and a number of hormones. The expression of these isoforms in the brain has been regarded as basically astrocytic, and to a lower extent, neuronal. We, however, demonstrate in this report, by radioimmunoassay and immunocytochemistry, that MT-I+II are expressed in primary cultures of rat microglia and that, furthermore, they are inducible by zinc and copper. Thus all major brain cell types may express the MT-I+II isoforms and respond with increased protein levels to physiological stimuli such as increased extracellular zinc and copper content. In contrast, microglia MT-I+II levels are not affected by either the glucocorticoid dexamethasone or the cytokine IL-1 under the experimental conditions.
Instituto de Biología Fundamental V. Villar i Palasí y Departamento de Bioquímica y Biología Molecular, Universidad Autónoma de Barcelona, Bellaterra, Spain.
L
L
Agullo
A
A
Garcia
J
J
Hidalgo
D000818:Animals; D002478:Cells, Cultured; D002531:Cerebellum / Q000187:drug effects* / Q000378:metabolism; D003300:Copper / Q000494:pharmacology*; D007150:Immunohistochemistry; D008668:Metallothionein / Q000096:biosynthesis*; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D015032:Zinc / Q000494:pharmacology*
D003300:Copper; D008668:Metallothionein; D015032:Zinc