Effect of Abeta exposure on the mRNA expression patterns of voltage-sensitive calcium channel alpha 1 subunits (alpha 1A-alpha 1D) in human SK-N-SH neuroblastoma.
Evidence for loss of Ca(2+) homeostasis through voltage-sensitive Ca(2+) channels (VSCCs) contribution to neuronal degeneration induced by beta-amyloid protein (Abeta) is considerable and rapidly increasing. Thus, the expression patterns of four alpha(1) subunits for P/Q (alpha(1A))-, N (alpha(1B))-, and L (alpha(1C) and alpha(1D))-type VSCCs before and after Abeta exposure were investigated in human SK-N-SH neuroblastoma. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed a constitutive and abundant co-expression of mRNA for alpha(1A) and alpha(1D) subunit in control cells. The mRNA expression of another L-type subunit alpha(1C) was undetectable in control cells while N-type subunit alpha(1B) was relative lower when compared to alpha(1A) and alpha(1D) subunits. Interestingly, mRNA levels of alpha(1A), alpha(1B), and alpha(1C) were remarkably and time-dependently increased in response to Abeta (20 microM) for 72 h culture period. In contrast, the constitutively expressed alpha(1D) mRNA was not further modified during Abeta exposure. Western blot analysis of four alpha(1) subunits expression was consistent with the findings obtained by RT-PCR. In conclusion, our results suggested that P/Q-, N-, as well as L-type Ca(2+) channel genes might be existed in SK-N-SH cells. Among them, mRNA for alpha(1A), alpha(1B), and alpha(1D) were expressed constitutively while alpha(1C) were inducible. Furthermore, Abeta exposure selectively modulates the transcription of alpha(1A), alpha(1B), and alpha(1C) subunits. These suggested that except activating of existed VSCCs, up-regulation of alpha(1) subunits expression might also contribute to Abeta-induced neuronal toxicity and the complex of these VSCCs expression may participate in Ca(2+) current disturbance in Alzheimer's disease.
Chiou
Wen-Fei
WF
Division of Basic Chinese Medical Research, National Research Institute of Chinese Medicine, No. 155-1, Sec. 2, Li-Nung St., Shipai, Taipei 112, Taiwan, ROC. wfchiou@cma23.nricm.edu.tw
D016229:Amyloid beta-Peptides / Q000502:physiology / Q000633:toxicity*; D015220:Calcium Channels / Q000096:biosynthesis* / Q000235:genetics; D020746:Calcium Channels, L-Type / Q000096:biosynthesis / Q000235:genetics; D020864:Calcium Channels, N-Type / Q000096:biosynthesis / Q000235:genetics; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D006801:Humans; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics
D016229:Amyloid beta-Peptides; C105656:CACNA1A protein, human; C500545:CACNA1B protein, human; C472073:CACNA1D protein, human; D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D020864:Calcium Channels, N-Type; C419385:L-type calcium channel alpha(1C); D012333:RNA, Messenger