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SPARC/osteonectin, an endogenous mechanism for targeting albumin to the blood-cerebrospinal fluid interface during

S A Liddelow1, K M Dziegielewska, K Møllgård

  • 1Department of Pharmacology, University of Melbourne, Parkville, Victoria, Australia. shaneal@unimelb.edu.au

The European Journal of Neuroscience
|September 9, 2011
PubMed

Insights

Researchers identified the albumin-binding protein SPARC in choroid plexus cells, suggesting it regulates protein transfer from blood to cerebrospinal fluid (CSF) in the developing brain.

Area of Science:

  • Neuroscience
  • Developmental Biology
  • Biochemistry

Background:

  • Choroid plexus epithelial cells facilitate plasma protein transfer to cerebrospinal fluid (CSF).
  • The precise mechanism of this protein transfer, especially in the developing brain, remains unclear.
  • Understanding this process is crucial for comprehending brain development and function.

Purpose of the Study:

  • To investigate the role of the albumin-binding protein SPARC in protein transfer across the blood-CSF barrier.
  • To determine the expression pattern and regulation of SPARC in the choroid plexus during development.
  • To elucidate the molecular mechanisms governing protein uptake into the CSF.

Main Methods:

  • Utilized the marsupial Monodelphis domestica as a model organism.
  • Employed real-time PCR and Western blot analysis to quantify SPARC expression.
  • Used immunocytochemistry to assess the co-localization and cellular location of SPARC and albumin.
  • Experimentally manipulated blood albumin concentrations to observe SPARC's responsiveness.

Main Results:

  • SPARC was detected in a specific subset of choroid plexus epithelial cells throughout development and into adulthood.
  • SPARC expression levels were higher in younger animals and decreased with age.
  • SPARC co-localized with albumin, suggesting a role in albumin recognition and uptake.
  • SPARC expression and cell positivity were modulated by changes in blood albumin levels.

Conclusions:

  • SPARC is identified as a key molecule involved in regulating the transport of proteins, such as albumin, from blood to CSF.
  • Protein transfer across the blood-CSF barrier is a developmentally and physiologically regulated process.
  • SPARC may act as a recognition site facilitating albumin uptake into the CSF.

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