Clusterin Expression and Localization in the Brain

After its identification in bovine neural tissue1 clusterin was identified in the CNS as a mRNA species with increased abundance in AD hippocampus7,8 and scrapie-infected hamster brain.9 Clusterin mRNA has a similar regional distribution in normal rat and human brain, being widely found in astrocytes throughout the brain, with regional selectivity for neurons.10 Immunohistological localization of clusterin reveals similar selectivity for neurons but few clusterin-positive astrocytes in normal...

Specificity to Alzheimers Disease

Upregulation of clusterin and abnormal staining of lesions for apoE is not limited to AD. Brain levels of clusterin seem to be elevated in many conditions involving injury or chronic inflammation of the brain. Elevated levels of the mRNA for clusterin are seen in the hippocampus in Pick's disease as well as in AD.4 Abnormal staining for clusterin has been seen in dystrophic neurites and some NFTs in the Parkinson's dementia complex of Guam (Fig. 7.1). It has also been seen in humans in ischemic...

Concluding Remarks

In the adult mammalian brain, clusterin sites of expression are more widespread than those of apolipoprotein E (Table 2.1). Both proteins are produced by glial cells, predominantly by astrocytes and ependymal cells. In contrast, only clusterin is synthesized by neurons, although not by all of them, whereas only apoE mRNA can be detected in what appears to be a restricted set of microglial cells. Since both proteins are secreted, the sites of synthesis are not necessarily identical to the sites...