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RESEARCH PRODUCT

Expression of neurotrophins, GDNF, and their receptors in rat thyroid tissue

Q ChengGiuseppa MudòG CanigliaNatale BelluardoM. CorsaroF FrascaDaniele F. CondorelliA Belfiore

subject

endocrine systemmedicine.medical_specialtyGlial Cell Line-Derived Neurotrophic Factor ReceptorsHistologyendocrine system diseasesThyroid GlandGene ExpressionNerve Tissue ProteinsReceptors Nerve Growth FactorNeurotrophin-3Tropomyosin receptor kinase AFollicular cellPathology and Forensic MedicineNeurotrophin 3Proto-Oncogene ProteinsInternal medicinemedicineGlial cell line-derived neurotrophic factorAnimalsDrosophila ProteinsHumansLow-affinity nerve growth factor receptorReceptor trkCGlial Cell Line-Derived Neurotrophic FactorNerve Growth FactorsRNA MessengerReceptor trkAReceptor Ciliary Neurotrophic FactorbiologyBrain-Derived Neurotrophic FactorProto-Oncogene Proteins c-retReceptor Protein-Tyrosine KinasesCell BiologyRatsCell biologyEndocrinologynervous systemProto-Oncogene Proteins c-retbiology.proteinGDNF family of ligandsNeurotrophin

description

Levels of mRNA for neurotrophins (brain-derived neurotrophic factor, BDNF; neurotrophin 3, NT-3; neurotrophin 4, NT-4) and their receptors (trkA, trkB, trkC) and for glial cell line-derived neurotrophic factor (GDNF) and its receptors (ret, GDNFR-alpha) were measured in rat thyroid tissue by ribonuclease protection assays. In thyroid tissue the NT-3 mRNA level was threefold lower and the NT-4 mRNA level sixfold higher than those detected in adult rat hippocampus, while BDNF mRNA was undetectable. Very low levels of mRNA for truncated trkB and trkC receptors and no catalytic trkA, trkB or trkC were found. In conclusion NT-3 and NT-4, but not the corresponding functional receptors, are expressed in the thyroid tissue. Therefore, it is unlikely that these factors serve a direct local autocrine or paracrine function in thyroid cell types, and a target-derived mode of action on neurons innervating the thyroid tissue is suggested. An opposite result has been found for the neurotrophic factor GDNF: thyroid tissue showed a high level of transcripts for the GDNF receptor subunits (GDNFR-alpha and Ret), while GDNF mRNA was undetectable. The in situ hybridization analysis of GDNFR-alpha and ret mRNA revealed an interesting difference in the cell distribution of these transcripts: ret mRNA is selectively expressed in a subpopulation of cells scattered in the follicular epithelium and in the interfollicular spaces, while GDNFR-alpha expression is more homogeneous and widespread, including the more abundant cell type of the thyroid gland: the follicular cell. Double-labeling in situ hybridization/immunocytochemistry experiments, with a specific marker (calcitonin), showed that parafollicular cells express ret but not GDNFR-alpha. This differential distribution of the GDNF receptor components (GDNFR-alpha and ret) may reflect a peculiar biological role in intercellular communication in the thyroid gland.

yearjournalcountryeditionlanguage
1999-02-18Cell and Tissue Research
https://doi.org/10.1007/s004410051252