Extracellular signal-regulated kinases, P38 and c-Jun N-terminal kinases phosphorylation changes in PC12 cells with diabetic disturbances and comorbid excitotoxicity - a preliminary report

Abstract

Phosphorylation of amino acid residues of extracellular signal-regulated kinases (ERK), p38 and c-Jun N-terminal kinases (JNK) contributes to the initiation of complex pathways of intracellular signal transduction, which play a role in the development of excitotoxicity, which is important in pathogenesis both in diabetes and neurodegeneration. Due to reports on the relationship between these two diseases, it is important to explore pathways in the coexistence of both of them. This study investigated ERK, p38 and JNK protein kinases phosphorylation changes in diabetic in vitro conditions with accompanying excitotoxicity reflected by high L-glutamate concentrations. An InstantOne ELISA test in cell lysates was performed to evaluate the intensity of phosphorylation of ERK, p38 and JNK occurring as a result of the incubation of undifferentiated PC12 cells with solutions of glucose (G₁,G₂), insulin (I₁,I₂) and L-glutamate (L₁,L₂). We observed increased phosphorylation of JNK (Thr¹⁸³/Tyr¹⁸⁵) and p38 (Thr¹⁸⁰/Tyr¹⁸²) kinases. For both these kinases, we have shown an increase in phosphorylation in case of double combinations for the following reagents: G₁I₁, G₁I₂, G₂I₁, G₂I₂, G₂L₁, I₂L₂ and the triple ones: G₁I₂L₁ and G₂I₁L₂. The research based on the analysis of selected protein kinases under diabetic conditions with accompanying excitotoxicity, represents an important cognitive issue for research on neurodegenerative disorders resulting from long-term type 2 diabetes. The confirmed changes in protein phosphorylation of p38 and JNK kinases suggests changes in the conformation and activity of these proteins under conditions of increased excitotoxicity resulting from diabetes.