Effect of protein kinase A inhibitors on the production of A beta 40 and Abeta 42 by human cells expressing normal and Alzheimer's disease-linked mutated beta APP and presenilin 1
P. Marambaud et al., Effect of protein kinase A inhibitors on the production of A beta 40 and Abeta 42 by human cells expressing normal and Alzheimer's disease-linked mutated beta APP and presenilin 1, BR J PHARM, 126(5), 1999, pp. 1186-1190
1 We previously established that the formation of both alpha- and beta/gamm
a-secretase-derived products generated by human embryonic kidney 293 cells
(HEK293) expressing either wild type or mutant beta APP could be stimulated
by agonists of the cyclic AMP/protein kinase A pathways. This cyclic AMP-d
ependent effect modulates post-translational events since it is not prevent
ed by actinomycin D or cycloheximide.
2 We show here that two protein kinase A inhibitors, H89 and PKI, both trig
ger dose-dependent inhibition of the basal constitutive production of A bet
a 40 and A beta 42 by HEK293 cells expressing wild type beta APP751.
3 H89 also potently inhibits the total A beta produced by the neocortical n
euronal cell line TSM1.
4 These two inhibitors also drastically reduce the recovery of A beta 40 an
d A beta 42 produced by HEK293 cells expressing the Swedish (Sw) beta APP a
nd M146V-presenilin 1 (PS1) mutations responsible for cases of the early-on
set forms of Familial Alzheimer's disease (FAD).
5 By contrast, H89 and PKI do not significantly affect the recovery of the
physiological alpha-secretase-derived fragment APP alpha.
6 Our study indicates that protein kinase A. inhibitors selectively lower t
he formation of A beta 40 and A beta 42 in human cells expressing normal an
d mutant beta APP and PS1 without affecting the physiological alpha-secreta
se pathway in these cells. Selective inhibitors of protein kinase A may be
of therapeutic value in both sporadic and Familial Alzheimer's disease, sin
ce they may decrease the production of A beta that is thought to be respons
ible for the neurodegenerative process.