| abstract |
It has been discovered that the stimulation of β-adrenergic receptors, which activate cAMP formation, gives rise to increased APP and GFAP synthesis in astrocytes. Hence, the in vitro or in vivo exposure of neuronal cells to certain compositions comprising β-adrenergic receptor ligands or agonists, including, e.g., norepinephrine, isoproterenol and the like, increases APP mRNA transcription and consequent APP overproduction. These increases are blocked by β-adrenergic receptor antagonists, such as propranolol. The in vitro or in vivo treatment of these cells with 8Br-cAMP, prostaglandin E2 (PG E2), forskolin, and nicotine ditartrate also increased APP synthesis, including an increase in mRNA and holoprotein levels, as well as an increase in the expression of glial fibrillary acidic protein (GFAP). Compositions and methods are disclosed of regulating APP overexpression and mediating reactive astrogliosis through cAMP signaling or the activation of β-adrenergic receptors. It has further been found that the increase in APP synthesis caused by 8Br-cAMP, PG E2, or forskolin is inhibited by immunosuppressants, immunophilin ligands, or anti-inflammatory agents, such as cyclosporin A, and FK-506 (tacrolimus), as well as ion-channel modulators, including ion chelating agents such as EGTA, or calcium/calmodulin kinase inhibitors, such as KN93. The present invention has broad implications in the alleviation, treatment, or prevention of neurological disorders and neurodegenerative diseases, including Alzheimer's Disease. |