Expression of the kallikrein gene family in normal and Alzheimer's diseasebrain

The human kallikrein gene family consists of 15 serine proteases. We examin ed the expression of the kallikrein genes in human cerebral cortex and hipp ocampus by RT-PCR and compared their expression between Alzheimer's disease (AD) and control tissue. KLKI, 4, 5, 6, 7, 8, 10, 11, 13 and 14 are expres sed in both cerebral cortex and hippocampus. KLK9 is expressed in cortex bu t not hippocampus, whereas KLK2, 3, 12 and 15 are not expressed in either t issue. We demonstrate an I 1.5-fold increase in KLK8 mRNA levels in AD hipp ocampus compared to controls. The KLK8 gene product, neuropsin, processes e xtracellular matrix and is important for neuronal plasticity. Therefore, th e increase in KLK8 could have detrimental effects on hippocampal function i n AD. NeuroReport 12:2747-2751 (C) 2001 Lippincott Williams & Wilkins.