Identification and expression of the epithelial Muc1 mucin in normal feline tissues

Many pathogens require direct binding to, or penetration of, mucosal cells to cause pathology. Cell surface mucins are critical components of mucosal defense. Mucin 1, named MUC1 in humans and Muc1 in non-human species, is a transmembrane glycoprotein expressed in apical mammalian epithelia] tissues. The aim of this study was to determine the Muc1 profile expression in healthy cat epithelial tissues. An extensive analysis of Muc1 expression was performed by immunohistochemistry (IHC), Western blot (WB) and RT-PCR. By IHC, the presence of Muc1 protein was observed in the epithelial cells of the esophagus, stomach, trachea, lung, small and large intestine, liver, pancreas, salivary glands, lactating mammary glands and bladder. The predominantly linear patterns of reaction as well as the ubiquitous expression of feline Mucl were consistent with normal human tissues. By WB, a band of 35 kDa, corresponding to that predicted for the Mucl cytoplasmic tail, was detected. The RT-PCR analysis showed a fragment of 115 bp, consistent with that found in MCF7 and T47D human cell lines. The results showed that the widest distribution of feline Mucl expression is in the mucosal tissues most at risk of infections such as the gastrointestinal tract, respiratory tract and lactating mammary gland. This study provides a normal model of cat Mucl pattern expression as a starting point to evaluate and compare the expression of this epithelial mucin in pathological feline tissues. We believe that the CT33 antibody and the universal primers designed could be valuable tools for veterinary pathologists involved in the diagnostic interpretation of alterations in Muc1 expression of infected tissues in cats. (C) 2009 Elsevier B.V. All rights reserved.