Immunological identification of vesicular nucleotide transporter in intestinal L cells

Biol Pharm Bull. 2014;37(7):1090-5. doi: 10.1248/bpb.b14-00275.

Abstract

It is well established that vesicular nucleotide transporter (VNUT) is responsible for vesicular storage of nucleotides such as ATP, and that VNUT-expressing cells can secrete nucleotides upon exocytosis, playing an important role in purinergic chemical transmission. In the present study, we show that VNUT is expressed in intestinal L cells. Immunohistochemical evidence indicated that VNUT is present in glucagon-like peptide 1 (GLP-1) containing cells in rat intestine. VNUT immunoreactivity is not co-localized with GLP-1, a marker for secretory granules, and synaptophysin, a marker for synaptic-like microvesicles (SLMVs). Essentially the same results were obtained for GLUTag clonal L cells. Sucrose density gradient analysis confirmed that VNUT is present the light fraction, unlike secretory granules. These results demonstrate that intestinal L cells express VNUT in either the unidentified organelles at light density other than secretory granules and SLMVs or a subpopulation of SLMVs, and suggest that L cells are purinergic in nature and secrete nucleotides independent of GLP-1 secretion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Brain / cytology
  • Brain / metabolism
  • Cell Culture Techniques
  • Enteroendocrine Cells / metabolism*
  • Fluorescent Antibody Technique, Indirect
  • Glucagon-Like Peptide 1 / metabolism
  • Intestine, Small / cytology
  • Intestine, Small / metabolism*
  • Male
  • Mice, Inbred C57BL
  • Microscopy, Fluorescence
  • Nucleotide Transport Proteins* / biosynthesis
  • Nucleotide Transport Proteins* / isolation & purification
  • Rats, Wistar
  • Receptors, Purinergic / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Synaptic Vesicles / metabolism
  • Synaptophysin / biosynthesis
  • Synaptophysin / isolation & purification
  • Vesicular Glutamate Transport Proteins / biosynthesis
  • Vesicular Glutamate Transport Proteins / isolation & purification

Substances

  • Nucleotide Transport Proteins
  • Receptors, Purinergic
  • Slc17a9 protein, mouse
  • Slc17a9 protein, rat
  • Synaptophysin
  • Syp protein, mouse
  • Syp protein, rat
  • Vesicular Glutamate Transport Proteins
  • Glucagon-Like Peptide 1
  • Adenosine Triphosphate