The Interplay of Akt and ERK in Aβ Toxicity and Insulin-Mediated Protection in Primary Hippocampal Cell Culture.
It is not known if insulin prevents Aβ-induced cell death, MAPK, and Akt activity in isolated hippocampal cell culture. This study was aimed to explore the effect of insulin on Aβ-induced cell death and ERK and Akt signaling alteration in isolated hippocampal cell culture. Additionally, it was desirable to assess if there is any interaction between these two pathways. The hippocampal cells were derived from fetuses at the embryonic day 18-19. The cells were treated with different drugs, and MTT assay, morphological assessments, and Western blot were done. Insulin prevented Aβ-induced cell death and caspase-3 cleavage. Aβ-induced toxicity was aligned with decrement of the phosphorylated Akt (pAkt) which was prevented by insulin. The PI3 kinase inhibitor, LY294002, decreased pAkt and abolished the protective effect of insulin. Aβ exposure increased phosphorylated ERK (pERK) in parallel with cell death and apoptosis. Insulin-inhibited ERK activation (phosphorylation) induced by Aβ and PD98059 (as ERK inhibitor) did not affect the protective effect of insulin. One of the interesting finding of this study was the interplay of Akt and ERK in Aβ toxicity and insulin-mediated protection; meaning that there is an inverse relation between pERK and pAkt, in a way that PI3-Akt pathway inhibition leads to pERK increment while ERK inhibition causes Akt phosphorylation (activation). This study showed, for the first time, that insulin protects against Aβ toxicity in isolated hippocampal cell culture via modulating Akt and ERK phosphorylation and also revealed an interaction between those signals in Aβ toxicity and insulin-mediated protection.
Department of Physiology and Neurophysiology Research Center, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Rasoul
R
Ghasemi
Department of Physiology and Shiraz Neuroscience Research Center, Shiraz University of Medical Sciences, Zand Street, Shiraz, Iran. marmoosavi@sums.ac.ir.|Nanotechnology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. marmoosavi@sums.ac.ir.
Maryam
M
Moosavi
Department of Physiology and Shiraz Neuroscience Research Center, Shiraz University of Medical Sciences, Zand Street, Shiraz, Iran. zarifkara@sums.ac.ir.
Asadollah
A
Zarifkar
Department of Physiology and Shiraz Neuroscience Research Center, Shiraz University of Medical Sciences, Zand Street, Shiraz, Iran.
Karim
K
Rastegar
Neurobiology Research Center and Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Nader
N
Maghsoudi
D016229:Amyloid beta-Peptides / Q000037:antagonists & inhibitors / Q000633:toxicity*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000502:physiology*; D005419:Flavonoids / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D007328:Insulin / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D009025:Morpholines / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000502:physiology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010446:Peptide Fragments / Q000037:antagonists & inhibitors / Q000633:toxicity*; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D010766:Phosphorylation / Q000187:drug effects; D061251:Primary Cell Culture; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
D016229:Amyloid beta-Peptides; D002867:Chromones; D005419:Flavonoids; D007328:Insulin; D009025:Morpholines; D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D010446:Peptide Fragments; D047428:Protein Kinase Inhibitors; C074636:amyloid beta-protein (25-35); C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D053148:Caspase 3; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one
Akt; Alzheimer’s disease; Beta amyloid; Caspase-3; ERK; Hippocampal cell culture