Acylase 1 expression in rat intestinal crypt–villus axis

Acylase 1 was investigated at the cellular level in the rat small intestine along the enterocyte–differentiation axis. As confirmed by microscopic analysis, villus tip cells and crypt cells of rat jejunal mucosa were successfully separated using the Weiser method. The proliferating undifferentiated crypt cells showed much higher ACY 1 activity levels than the villus cells, with a 6.4-fold decrease as the cells migrated and differentiated along the crypt–villus axis. RT-PCR studies on mRNA extracted from isolated cells showed that ACY 1 mRNA was mainly expressed in crypt cells, reaching levels that were 12-fold higher than those recorded in other cell types along the whole enterocyte differentiation axis. It was concluded that the expression of ACY 1 in the intestinal crypt cells is regulated at the mRNA level. Immunohistochemistry revealed the expression of ACY 1 in the absorbing lineage cells from the ileal and colonic crypts and the absence of ACY 1 in the mucus producing goblet cells. These findings proposed ACY 1 as a new marker transcript for absorbing cells of intestinal crypt, which can be used to monitor the process of intestinal N-α-acetylated protein metabolism.