Methods for identifying substances for the treatment of Alzheimer's disease

1. A method for identifying a test substance useful in the treatment of Alzheimer's disease, which method comprises the following steps:

(a) contacting a test neuronal cell with the test substance and Semaphorin 3A protein under conditions wherein the addition of the Semaphorin 3A protein alone induces withdrawal, retraction or collapse of the nerve growth cone;

(b) contacting a control neuronal cell with the Semaphorin 3A protein alone under the same conditions;

(c) comparing withdrawal, retraction or collapse of the nerve growth cone in the test neuronal cell of step (a) and the control neuronal cell of step (b);

(d) identifying as a substance useful for the treatment of Alzheimer's disease the test substance which inhibits withdrawal, retraction or collapse of the nerve growth cone in the test neuronal cell of step (a) as compared to the control neuronal cell of step (b); and

(e) administering the test compound identified as useful for the treatment of Alzheimer's disease in step (d) to an animal model of Alzheimer's disease.

2. The method according to claim 1 , wherein the Semaphorin 3A is human Semaphorin 3A.