Serum opens tight junctions and reduces ZO-1 protein in retinal epithelial cells

Chih Wei Chang, Xiliang Wang, Ruth B. Caldwell

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


We have shown previously that serum inhibits tight junction formation in a retinal epithelial cell culture model for the blood-brain barrier. We have now examined in detail the effects of serum on the tight junctions. Our data show that serum induces a breakdown in tight junction function as indicated by decreased transepithelial electrical resistance and increased permeability. Rat serum had effects similar to those of bovine serum, indicating that the activity is species-independent. The effect is concentration-dependent, reversible, and specific for the apical surface, suggesting the involvement of a specific receptor-ligand interaction. Differences in the time course, response magnitude, and structural manifestations between the serum-induced breakdown and that induced by switching the cultures to a low-calcium medium suggest fundamental differences in their mechanisms. The calcium switch results in an immediate and complete junctional breakdown with cell retraction and perinuclear translocation of both actin and the tight junction protein zonula occludens- 1. The serum-induced breakdown occurs slowly, is incomplete, and is manifested structurally by decreases in zonula occludens-1 protein, whereas actin organization is unchanged. Thus, serum induces a specific breakdown in retinal epithelial cell tight junctions that may be mediated by effects on the expression of zonula occludens-1.

Original languageEnglish (US)
Pages (from-to)859-867
Number of pages9
JournalJournal of Neurochemistry
Issue number2
StatePublished - Aug 1997


  • Blood-brain barrier
  • Cell culture
  • Intercellular junctions
  • Retinal pigment epithelium
  • Serum
  • Tight junctions

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience


Dive into the research topics of 'Serum opens tight junctions and reduces ZO-1 protein in retinal epithelial cells'. Together they form a unique fingerprint.

Cite this