Glucagon-like Peptide-1 Secretion Is Inhibited by Lysophosphatidic Acid

Int J Mol Sci. 2022 Apr 9;23(8):4163. doi: 10.3390/ijms23084163.


Glucagon-like peptide-1 (GLP-1) potentiates glucose-stimulated insulin secretion (GSIS). While dozens of compounds stimulate GLP-1 secretion, few inhibit. Reduced GLP-1 secretion and impaired GSIS occur in chronic inflammation. Lysophosphatidic acids (LPAs) are bioactive phospholipids elevated in inflammation. The aim of this study was to test whether LPA inhibits GLP-1 secretion in vitro and in vivo. GLUTag L-cells were treated with various LPA species, with or without LPA receptor (LPAR) antagonists, and media GLP-1 levels, cellular cyclic AMP and calcium ion concentrations, and DPP4 activity levels were analyzed. Mice were injected with LPA, with or without LPAR antagonists, and serum GLP-1 and DPP4 activity were measured. GLUTag GLP-1 secretion was decreased ~70-90% by various LPAs. GLUTag expression of Lpar1, 2, and 3 was orders of magnitude higher than Lpar4, 5, and 6, implicating the former group in this effect. In agreement, inhibition of GLP-1 secretion was reversed by the LPAR1/3 antagonist Ki16425, the LPAR1 antagonists AM095 and AM966, or the LPAR2 antagonist LPA2-antagonist 1. We hypothesized involvement of Gαi-mediated LPAR activity, and found that intracellular cyclic AMP and calcium ion concentrations were decreased by LPA, but restored by Ki16425. Mouse LPA injection caused an ~50% fall in circulating GLP-1, although only LPAR1 or LPAR1/3 antagonists, but not LPAR2 antagonism, prevented this. GLUTag L-cell and mouse serum DPP4 activity was unchanged by LPA or LPAR antagonists. LPA therefore impairs GLP-1 secretion in vitro and in vivo through Gαi-coupled LPAR1/3 signaling, providing a new mechanism linking inflammation with impaired GSIS.

Keywords: L-cells; glucagon-like peptide 1; inflammation; lysophosphatidic acid.

MeSH terms

  • Animals
  • Calcium
  • Cyclic AMP
  • Dipeptidyl Peptidase 4*
  • Glucagon-Like Peptide 1* / metabolism
  • Inflammation
  • Lysophospholipids / metabolism
  • Lysophospholipids / pharmacology
  • Mice
  • Receptors, Lysophosphatidic Acid / metabolism


  • Lysophospholipids
  • Receptors, Lysophosphatidic Acid
  • Glucagon-Like Peptide 1
  • Cyclic AMP
  • Dipeptidyl Peptidase 4
  • Calcium