A3 receptor agonist, Cl-IBMECA, potentiate glucose-induced insulin secretion from MIN6 insulinoma cells possibly through transient Ca²⁺ entry

Abstract

Diabetes incidence showed ascending trends in recent years indicating urgent need for new therapeutic agents. Extracellular adenosine signaling showed promising results. However, role of its A3 receptor in pancreatic β-cells proliferation and insulin secretion is not well established. Thus, we aimed to determine its main signaling mediators in MIN6 insulinoma cell line. A3 adenosine receptor (A3AR) expression was confirmed using RT-PCR. Receptor functionality was evaluated by measurements of cAMP, using ELISA kit, and intracellular Ca2+ levels, using Fura 2/AM probe in response to the specific A3AR agonist (Cl- IBMECA). Insulin ELISA kit was used to measure insulin release. Herein, we mentioned that MIN6 cells express active form of A3AR, which decreased cAMP levels with the half maximal effective concentration (EC50) value of 5.61. [Ca2+]i Levels transiently (approximately 120 sec) increased in response to the agonist. Cl-IBMECA increase insulin secretion at 0.01-1 μM, but showed an inhibitory effects at higher concentrations (1-10 μM). Altogether, we found that in MIN6 cells, A3AR, possibly through Ca2+ mediated signaling pathways, potentiated glucose-induced insulin secretion.

Klotho induces insulin resistance possibly through interference with GLUT4 translocation and activation of Akt, GSK3β, and PFKfβ3 in 3T3-L1 adipocyte cells

“…For further confirmation of 3T3-L1 differentiation, peroxisome proliferator-activated receptor gamma (PPAR-γ) gene expression levels also evaluated by semi-quantitative real-time polymerase chain reaction (qRT-PCR). As previously described (21), total RNA was extracted from 3 × 10 5 3T3-L1 differentiated cells using RNX-Plus solution (Sinaclon, I.R. Iran).…”

Diabetes and hypertension: Pivotal involvement of purinergic signaling

“…Additional A 2A and A 2B receptor activation protects islet grafts from T cell–mediated injury [ 124 ]. The A 3 receptor agonist, Cl-IBMECA, potentiates glucose-induced insulin secretion from MIN6 insulinoma cells possibly through transient Ca 2+ entry [ 118 ]. Finally, an elevated Ado concentrations in endothelial cells due to adenosine kinase deficiency ameliorates diet-induced insulin resistance and metabolic disorders [ 135 ].…”

Metabolomic identification of biochemical changes induced by fluoxetine in an insulinoma cell line (MIN6)

“…The insulinoma cell line MIN6 model is a valuable cell model for studying the molecular mechanism of drugs in pancreatic beta cells, given that the model cells mimic several beta cell functions of humans. In this study, MIN6 cells were exposed to fluoxetine with a concentration similar to that measured in patients ( 7 8 ). Following treatment, many biochemical changes subsequently occur, which are reversible with fluoxetine treatment ( 5 9 ).…”

“…Following treatment, many biochemical changes subsequently occur, which are reversible with fluoxetine treatment ( 5 9 ). Therefore, the MIN6 model of beta cell function is considered suitable for investigating the effect of fluoxetine on the molecular mechanism of pancreatic beta cells ( 7 8 9 ).…”