In:
Cellular Physiology and Biochemistry, S. Karger AG, Vol. 35, No. 4 ( 2015), p. 1537-1545
Abstract:
Aims: GPR40/FFAR1 mediates palmitate-induced stimulation of insulin secretion but its involvement in lipotoxicity is controversial. Our previous observations suggest that FFAR1/GPR40 agonists protect against lipotoxicity although the underlying mechanism remains elusive. The present study examines the role of ERK1/2 and GPR40/FFAR1 in palmitate-induced stimulation of insulin secretion and beta cell death. Methods: Insulin secretion of INS-1E cells was measured by radioimmunoassay. Protein phosphorylation was examined on Western blots. Apoptosis was assessed by TUNEL staining. Results: Palmitate and the GPR40/FFAR1 agonist TUG-469 increased phosphorylation of ERK1/2 at low (2.8 mmol/L) and high (12 mmol/L) glucose but stimulated insulin secretion only at high glucose. The MEK1 inhibitor PD98059 significantly reduced phosphorylation of ERK1/2 but did not reverse the stimulation of secretion induced by glucose, palmitate or TUG-469. PD98059 rather augmented glucose-induced secretion. Prolonged exposure to palmitate stimulated apoptosis, an effect counteracted by TUG-469. PD98059 accentuated palmitate-induced apoptosis and reversed TUG-469-mediated inhibition of cell death. Conclusions: Activation of ERK1/2 by palmitate and GPR40/FFAR1 agonist correlates neither with stimulation of insulin secretion nor with induction of apoptosis. The results suggest a significant anti-apoptotic role of ERK1/2 under conditions of lipotoxicity.
Type of Medium:
Online Resource
ISSN:
1015-8987
,
1421-9778
Language:
English
Publisher:
S. Karger AG
Publication Date:
2015
detail.hit.zdb_id:
1482056-0
SSG:
12
SSG:
15,3
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