title: Brain aging in acquired immunodeficiency syndrome: increased ubiquitin-protein conjugate is correlated with decreased synaptic protein but not amyloid plaque accumulation.
abstract: Two neuropathological changes that are linked with biological and pathological aging were examined in subjects with end-stage acquired immunodeficiency syndrome (AIDS). Autopsy brain specimens were examined from 25 people who died from complications of AIDS and 25 comparison subjects who were human immunodeficiency virus (HIV)-negative, matched for age, gender, ethnicity, and postmortem time interval. These adults were stratified into three age groups: elderly (62 to 75 years), intermediate (55 to 60 years), and young (21 to 42 years). Ubiquitin-stained dotlike deposits (Ub-dots) and diffuse extracellular plaques containing the beta-amyloid (Abeta) fragment of the amyloid precursor protein (Abeta plaque) were both increased significantly in the hippocampal formation of older subjects. In subjects with AIDS, Ub-dots were increased whereas Abeta plaque counts were not significantly different. Western blotting confirmed that high-molecular-weight ubiquitin-protein conjugates (HMW-Ub-conj) were increased in AIDS. The band intensity of one HMW-Ub-conj species with an approximate molecular mass of 145 kDa was correlated significantly with increased acute phase inflammatory protein (a-1-antichymotrypsin) and decreased synaptophysin and growth-associated protein-43 band intensities. These results raise the possibility that HIV-related brain inflammation disturbs neuronal protein turnover through the ubiquitin-proteasome apparatus, and might increase the prevalence of age-associated neurodegenerative diseases by decreasing synaptic protein turnover through the proteasome.
authors.affiliation: Department of Pathology, The University of Texas Medical Branch, Galveston, Texas 77555-0785, USA. bgelman@utmb.edu
authors.forename: Benjamin B
authors.initials: BB
authors.lastname: Gelman
authors.forename: Kimberly
authors.initials: K
authors.lastname: Schuenke
mesh_terms: D015526:AIDS Dementia Complex / Q000378:metabolism* / Q000473:pathology*; D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism* / Q000473:pathology*; D016229:Amyloid beta-Peptides / Q000378:metabolism; D000686:Amyloidosis / Q000378:metabolism / Q000473:pathology; D003546:Cysteine Endopeptidases / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009097:Multienzyme Complexes / Q000378:metabolism; D058225:Plaque, Amyloid / Q000378:metabolism / Q000473:pathology; D046988:Proteasome Endopeptidase Complex; D013569:Synapses / Q000378:metabolism / Q000473:pathology; D025801:Ubiquitin / Q000378:metabolism*
chemical_list: D016229:Amyloid beta-Peptides; D009097:Multienzyme Complexes; D025801:Ubiquitin; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex