Pen-2 overexpression induces Aβ-42 production, memory defect, motor activity enhancement and feeding behavior dysfunction in NSE/Pen-2 transgenic mice

Pen-2 is a key regulator of the γ-secretase complex, which is involved in the production of the amyloid β (Aβ)-42 peptides, which ultimately lead to Alzheimer's disease (AD). While Pen-2 has been studied in vitro, Pen-2 function in vivo in the brains of transgenic (Tg) mice overexpressing human Pen-2 (hPen-2) protein has not been studied. This study aimed to determine whether Pen-2 overexpression could regulate the AD-like phenotypes in Tg mice. NSE/hPen-2 Tg mice were produced by the microinjection of the NSE/hPen-2 gene into the pronucleus of fertilized eggs. The expression of the hPen-2 gene under the control of the NSE promoter was successfully detected only in the brain and kidney tissue of NSE/hPen-2 Tg mice. Also, 12-month-old NSE/hPen-2 Tg mice displayed behavioral dysfunction in the water maze test, motor activity and feeding behavior dysfunction in food intake/water intake/motor activity monitoring system. In addition, tissue samples displayed dense staining with antibody to the Aβ-42 peptide. Furthermore, NSE/hPen-2 Tg mice exhibiting feeding behavior dysfunction were significantly more apt to display symptoms related to diabetes and obesity. These results suggest that Pen-2 overexpression in NSE/hPen-2 Tg mice may induce all the AD-like phenotypes, including behavioral deficits, motor activity and feeding behavior dysfunction, Aβ-42 peptide deposition and chronic disease induction.