Rat neural tissue cathepsin D: ultrastructural immunocytochemistry

Abstract

The cellular and subcellular localization of cathepsin D, an aspartyl endopeptidase, was investigated in the central and peripheral nervous systems of the rat by light and electron microscopic immunocytochemistry. The reaction of rabbit anti-rat brain cathepsin D within ventral cervical spinal cord, cerebellum, corpus callosum, caudate nucleus, optic nerve, trigeminal ganglion, fifth cranial nerve and sciatic nerve was localized with an indirect immunoperoxidase technique. A number of tissue processing methods were utilized, but only in tissues fixed in paraformaldehyde-lysine-periodate and sectioned at thicknesses of 25-50 micron could antibody penetration, enzyme protein immunoreactivity and intact morphology be reliably attained. Immunoreactive cathepsin D was present in lysosomes and pleomorphic dense bodies of neurons in the anterior horn of spinal cord, cerebellar Purkinje and granule cell layers, caudate nucleus and trigeminal ganglion. Lysosomal localization of cathepsin D was also documented in oligodendrocytes, astrocytes, endothelial cells and Schwann cells. Reaction product was not observed in microglia although its presence there would be expected. With these methods, reaction product was not detected in the Golgi saccules of any cell type.

The Distribution of Cathepsin D Activity in Adult and Aging Human Brain Regions

“…Both light-microscopic and electron-microscopic immunocytochemical assays showed that cathepsin D in the nervous system is localized mainly in lysosomes (Yokota and Atsumi, 1983;Snyder et al, 1985), a distribution similar to that found in other tissues. The enzyme is not present in all cells of the various tissues (Whitaker and Rhodes, 1983), and there are differences in its level in the various cells (Tummers et al, 1983).…”

“…The enzyme is not present in all cells of the various tissues (Whitaker and Rhodes, 1983), and there are differences in its level in the various cells (Tummers et al, 1983). In the brain, most ofthe activity is found in the neurons (Snyder et al, 1985;Cataldo et d., 1990). The nonlysosomal portion varies among the different cell types (Tummers et al, 1983).…”

Biotinylated fluorescent peptide substrates for the sensitive and specific determination of cathepsin D activity

“…CatD (E.C. 3.4.23.5) is a member of the aspartic protease family and widely distributed among all mammalian cells [1][2][3][4]. It is involved in the degradation of intracellular and extracellular proteins.…”

Alterations of the posttranslational processing of a lysosomal enzyme in C6 glioma cells

“…The aspartyl endopeptidase cathepsin D (EC 3.4.23.5) is present in most vertebrate cell types (Whitaker and Rhodes, 1983). Cathepsin D (CD) has been detected by ultrastructural immunocytochemistry in lysosomes of neurons and glia of the CNS (Yokata and Atsumi, 1985;Snyder et al, 1985). The precise function of this endopeptidase is not known, but it presumably affects intracellular protein degradation.…”