Abstract
The non-reducing disaccharide trehalose is biosynthesized in several species but not in vertebrates. However, trehalase, the enzyme required for its cleavage, has been observed in different mammalian organs. Even in humans, trehalase was detected in the gastrointestinal tract and the kidney. Trehalase is an intrinsic glycoprotein of the small intestine and kidney that transports trehalose and hydrolyses it to two glucose molecules. To our knowledge, no information is available about the in vivo distribution and localization of trehalase in the mammalian brain. Here, we report the occurrence and distribution of trehalase in vivo in the mouse brain using Western blotting and immunohistochemical techniques. Using an antibody against trehalase, we demonstrated that the enzyme showed a band with a molecular mass of approx. 70 kDa in the hippocampus, cerebral cortex, cerebellum and olfactory bulbs. Strong trehalase immunoreactivity was found in the perikarya and dendrites of neurons located in the hippocampus, cerebral cortex, Purkinje cells and mitral cells. Interestingly, Purkinje cells of the cerebellum showed higher immunoreactivity than neurons in the hippocampus and cerebral cortex. The distribution of trehalase appeared to be mainly related to neurons and was not detected in astrocytes. Independent of the presence of trehalose in neurons, the trehalase levels in neurons should have physiological significance. Investigating whether the interactions between trehalose and trehalase act on brain energy metabolism or have other not-yet-identified effects would also be interesting.