Tmem27 is upregulated by vitamin D in INS-1 cells and its serum concentrations are low in patients with autoimmune diabetes

Scand J Clin Lab Invest. 2014 Jun;74(4):358-65. doi: 10.3109/00365513.2014.898322. Epub 2014 Apr 3.

Abstract

Transmembrane protein 27 (Tmem27), which is expressed in pancreatic β-cells, plays an important role in insulin secretion and pancreatic β-cell proliferation. Analysis of the INS-1 cell proteome using stable isotope labeling by amino acids in cell culture (SILAC) in combination with LC-MS identified Tmem27 as the one of most robustly (up to seven-fold) upregulated proteins after treatment with the active metabolite of vitamin D, 1,25-(OH)2D3. Furthermore, we report that Tmem27 which is cleaved and released from, i.e. pancreatic β-cells, is present in human serum and its levels are significantly lower in subjects with autoimmune diabetes as compared to healthy individuals (13% of the levels). Additionally, Tmem27 correlated positively (0.70) with C-peptide serum levels in healthy subjects. Our data indicate that Tmem27 could be of potential value as a serum marker for the pathogenesis of diabetes and as such may warrant the development of measurement methods with lower limit of detection for its further validation.

Keywords: Diabetes; Tmem27; pancreatic β-cell; serum; vitamin D.

MeSH terms

  • Animals
  • Biomarkers / blood
  • C-Peptide / blood
  • Calcitriol / pharmacology
  • Case-Control Studies
  • Cell Line / drug effects
  • Diabetes Mellitus, Type 1 / blood
  • Diabetes Mellitus, Type 1 / metabolism*
  • Female
  • Humans
  • Insulin-Secreting Cells / drug effects
  • Insulin-Secreting Cells / metabolism
  • Male
  • Membrane Glycoproteins / blood
  • Membrane Glycoproteins / metabolism*
  • Rats
  • Up-Regulation
  • Vitamin D / pharmacology*

Substances

  • Biomarkers
  • C-Peptide
  • CLTRN protein, human
  • Cltrn protein, rat
  • Membrane Glycoproteins
  • Vitamin D
  • Calcitriol