Restoration of TEA-induced calcium responses in fibroblasts from Alzheimer's disease patients by a PKC activator.
Several alterations in fibroblasts of Alzheimer's disease (AD) patients have been described, including alterations in calcium regulation, protein kinase C (PKC), and potassium (K+) channels. Studies have also found reduced levels of the alpha isoform of PKC in brains and fibroblasts of AD patients. Since PKC is known to regulate ion channels, we studied K+ channel activity in fibroblasts from AD patients in the presence of (2S, 5S)-8-(1-decynyl)benzolactam (BL), a novel activator of PKC with improved selectivity for the alpha, beta, and gamma isoforms. We present evidence for restoration of normal K+ channel function, as measured by TEA-induced [Ca2+]i elevations, due to activation of PKC by BL. Representative patch-clamp data further substantiate the effect of BL on restoration of 113pS K+ channel activity. Immunoblotting analyses using an alpha-isozyme-specific PKC antibody confirm that BL-treated fibroblasts of AD patients show increased PKC activation. The present study suggests that PKC activator-based restoration of K+ channels may offer another approach to the investigation of AD pathophysiology, which in turn could lead to the development of a useful model for AD therapeutics.
Bhagavan
S
S
Laboratory of Applied Neuroscience, Georgetown University Medical Center, Washington, DC 20007-2197, USA.
Ibarreta
D
D
Ma
D
D
Kozikowski
A P
AP
Etcheberrigaray
R
R
D000544:Alzheimer Disease / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002273:Carcinogens / Q000494:pharmacology; D002478:Cells, Cultured; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005079:Excipients / Q000494:pharmacology; D005347:Fibroblasts / Q000737:chemistry / Q000166:cytology / Q000201:enzymology; D006801:Humans; D015151:Immunoblotting; D007769:Lactams / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D010704:Phorbols / Q000494:pharmacology; D015221:Potassium Channels / Q000502:physiology; D011493:Protein Kinase C / Q000032:analysis / Q000378:metabolism*; D019789:Tetraethylammonium / Q000494:pharmacology*
D002273:Carcinogens; D005079:Excipients; D007769:Lactams; D010704:Phorbols; D015221:Potassium Channels; C113786:benzolactam V8-310; D015240:Phorbol 12,13-Dibutyrate; D019789:Tetraethylammonium; D011493:Protein Kinase C; D002118:Calcium; C033085:phorbol; D004121:Dimethyl Sulfoxide