Possible role of scavenger receptor SRCL in the clearance of amyloid-beta in Alzheimer's disease

J Neurosci Res. 2006 Sep;84(4):874-90. doi: 10.1002/jnr.20992.

Abstract

Accumulation of beta-amyloid protein (Abeta) in the brain is a hallmark of Alzheimer's disease (AD), and Abeta-mediated pathogenesis could result from increased production of Abeta or insufficient Abeta clearance by microglia, astrocytes, or the vascular system. Cell-surface receptors, such as scavenger receptors, might play a critical role in the binding and clearing of Abeta; however, the responsible receptors have yet to be identified. We show that scavenger receptor with C-type lectin (SRCL), a member of the scavenger receptor family containing coiled-coil, collagen-like, and C-type lectin/carbohydrate recognition domains, is expressed in cultured astrocytes and microglia. In contrast to the low expression of SRCL in the wild-type mouse brain, in a double transgenic mouse model of AD (Tg-APP/PS1), immunohistochemistry showed that SRCL was markedly induced in Abeta-positive astrocytes and Abeta-positive vascular/perivascular cells, which are associated closely with cerebral amyloid angiopathy. In patients with AD, the distribution of SRCL was similar to that seen in the Tg-APP/PS1 temporal cortex. The presence of a large number of SRCL/Abeta double-positive particles in the intracellular compartments of reactive astrocytes and vascular/perivascular cells in Tg-APP/PS1 mice and AD patients suggests a role for SRCL in Abeta clearance. Moreover, CHO-K1 cells transfected with SRCL isoforms were found to bind fibrillar Abeta(1-42). These findings suggest that SRCL could be the receptor involved in the binding or clearing of Abeta by glial and vascular/perivascular cells in AD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / metabolism*
  • Alzheimer Disease / pathology
  • Amyloid beta-Peptides / metabolism*
  • Amyloid beta-Peptides / pharmacology
  • Animals
  • Animals, Newborn
  • Anticoagulants / pharmacology
  • Cells, Cultured
  • Cerebral Cortex / metabolism
  • Collectins / physiology*
  • Cricetinae
  • Cricetulus
  • Drug Interactions
  • Female
  • Gene Expression / drug effects
  • Humans
  • In Vitro Techniques
  • Male
  • Mice
  • Microglia / drug effects
  • Microglia / metabolism
  • Nerve Tissue Proteins / metabolism
  • Polysaccharides / pharmacology
  • Pregnancy
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Scavenger / physiology*
  • Reverse Transcriptase Polymerase Chain Reaction / methods

Substances

  • Amyloid beta-Peptides
  • Anticoagulants
  • COLEC12 protein, human
  • Collectins
  • Nerve Tissue Proteins
  • Polysaccharides
  • RNA, Messenger
  • Receptors, Scavenger
  • fucoidan