In certain embodiments compositions are provided that comprise a pentapeptide comprising the formula: C1-X2-X3-X4-C5 where C1 and C5 are independently selected cysteines or cysteine analogues, or other amino acids with sidechains suitable for cyclization, where the cysteines or cysteine analogs are attached to each other by a linkage that does not comprise X2, X3, and X4; where X2, X3, and X4 are independently selected amino acids; and the peptide, when administered to a cell alters APP signaling and/or switches APP processing from aberrant to normal. The compositions mitigate amyloid plaque formation.