Parotid secretory protein is an HDL-associated protein with anticandidal activity

Am J Physiol Regul Integr Comp Physiol. 2005 May;288(5):R1306-15. doi: 10.1152/ajpregu.00007.2004. Epub 2005 Jan 6.

Abstract

High-density lipoprotein (HDL) is part of innate immunity, protecting against infection and inflammation. Using a proteomic approach, we identified an amino acid sequence in a hamster HDL protein that showed homology to rat and mouse parotid secretory protein (PSP), a salivary protein secreted from the parotid glands. We cloned the cDNA encoding a putative hamster homolog of rat and mouse PSP. Searches for conserved domains of the protein showed that the COOH terminus of hamster PSP contains a region homologous to the NH2 termini of a family of HDL-associated proteins, including LPS-binding protein, cholesteryl ester transfer protein, and phospholipid transfer protein. In mice, PSP was also associated with HDL but was not detected in very-low-density lipoprotein, low-density lipoprotein, or lipoprotein-deficient sera. In addition to salivary glands, we found that PSP mRNA was expressed in lung, testis, and ovary. The level of PSP in HDL was increased after endotoxin injection in hamsters, but not in mice. Recombinant PSP inhibits growth of Candida albicans in culture. In summary, our results showed that PSP is a novel anticandidal protein associated with HDL.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Candida albicans / immunology*
  • Cricetinae
  • Endotoxins
  • Gene Expression
  • Immunity, Innate
  • Lipoproteins, HDL / blood*
  • Lipoproteins, HDL / chemistry
  • Lipoproteins, HDL / physiology
  • Mice
  • Molecular Sequence Data
  • Rats
  • Salivary Glands / metabolism
  • Salivary Proteins and Peptides / blood*
  • Salivary Proteins and Peptides / chemistry
  • Salivary Proteins and Peptides / physiology*
  • Sequence Homology, Amino Acid
  • Species Specificity

Substances

  • Bpifa2 protein, mouse
  • Bpifa2 protein, rat
  • Endotoxins
  • Lipoproteins, HDL
  • Salivary Proteins and Peptides