[HSP 70 is associated with abnormal cytoplasmic inclusions characteristic of neurodegenerative diseases]

Several degenerative diseases of the central nervous system are characterized by the presence of neuronal inclusions. One of these inclusions, neurofibrillary tangles in Alzheimer's disease, has been shown to contain ubiquitin that belongs to a group of proteins known as heat shock proteins. Subsequent studies revealed that ubiquitin is also associated with various neuronal inclusions including Lewy bodies, Pick bodies and hyaline inclusions. Very recently, ubiquitin has been found also to be associated with glial inclusions that are unique to multiple system atrophy. The close association of ubiquitin with varying cellular inclusions, together with its function in the proteolytic process, raised the hypothesis that ubiquitin may be involved in the degradation of abnormal proteins appearing in the damaged neurons and glial cells. In central nervous system, a group of heat shock proteins collectively known as HSP 70 is also present which is constitutive and/or inducible. Since HSP 70 has been suspected to play a crucial role degradation and repair of abnormal intracellular proteins, we hypothesized that HSP 70 may be associated with those inclusions, as the case with ubiquitin. To test this we performed immunohistochemical studies on brain tissues from patients with various neurodegenerative conditions by using specific polyclonal antibody to HSP 70. Brain tissues were obtained at autopsy from each three patients with Alzheimer's disease, Pick's disease, Parkinson's disease, amyotrophic lateral sclerosis (ALS) and multiple system atrophy. Tissues were fixed in buffered formalin and embedded in paraffin. Immunostaining was performed by the standard ABC method using diaminobenzidine as a chromogen. Sections were lightly stained with hematoxylin. Polyclonal antibodies were raised in rabbits against mouse HSP 70.(ABSTRACT TRUNCATED AT 250 WORDS)