TCDD alters PKC signaling pathways in developing neuronal cells in culture.
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is known to induce neurodevelopmental deficits such as poor cognitive development and motor dysfunction. However, the mechanism of TCDD-mediated neurotoxicity remains unclear. Since PKC signaling is one of the most pivotal events involved in neuronal function and development, we analyzed the effects of TCDD on the PKC signaling pathway in cerebellar granule cells derived from PND-7 rat brain. Immunoblot analysis revealed the presence of PKC-alpha, betaII, delta, epsilon, lambda and iota in both cytosol and membrane fractions of cerebellar granule cells, but PKC-gamma was below the detectable level. TCDD induced a significant translocation of PKC-alpha, -betaII and -epsilon from cytosol to membrane fraction (p<0.05) and a marginal translocation of PKC-delta at high dose only (p<0.1). It also increased RACK-1, an adaptor protein for PKC, in a dose-dependent manner. Exposure to TCDD induced a dose-dependent increase of both [3H] PDBu binding and the intracellular calcium level. The results suggest that the selective PKC isozymes and RACK-1 are involved in TCDD-mediated signaling pathway and these proteins may be possible molecular targets in neuronal cells for TCDD exposure. Our study provides basic data to understand mechanism of TCDD-induced neurotoxicity with respect to PKC signaling pathway and a scientific basis for improving the health risk assessment of neurotoxicants by identifying intracellular target molecules in neuronal cells.
Kim
Sun-Young
SY
Department of Pharmacology/Toxicology, Catholic University of Daegu, School of Medicine, Daegu, Republic of Korea.
Lee
Hyun-Gyo
HG
Choi
Eun-Jung
EJ
Park
Ki-Yeon
KY
Yang
Jae-Ho
JH
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects* / Q000473:pathology; D003600:Cytosol / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D007527:Isoenzymes / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000473:pathology; D009498:Neurotoxins / Q000633:toxicity*; D010455:Peptides / Q000378:metabolism; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D011493:Protein Kinase C / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D000075370:Receptors for Activated C Kinase; D018570:Risk Assessment; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology
D007527:Isoenzymes; D009498:Neurotoxins; D010455:Peptides; D000072317:Polychlorinated Dibenzodioxins; D000075370:Receptors for Activated C Kinase; C070301:peptide I; D011493:Protein Kinase C; D002118:Calcium