Liraglutide prevents beta-amyloid-induced neurotoxicity in SH-SY5Y cells via a PI3K-dependent signaling pathway.
OBJECTIVE
The aim of the study was to investigate the effects of the GLP-1 analog liraglutide on beta-amyloid (Aβ)-induced neurotoxicity in the human neuroblastoma cell line SH-SY5Y and study the underlying mechanisms.


METHODS
Cultured SH-SY5Y cells in vitro were randomly divided into normal control group, beta-amyloid (Aβ) group (20, 40, and 80 uM), and liraglutide pre-treatment group (10, 100, and 200 nM). Cell viability was determined by CCK-8 and lactate dehydrogenase (LDH). Based on its higher protection potentials, the effect of the liraglutide (100 nM) and wortmannin (200 nM) on beta-amyloid (Aβ) group (40 uM) damage in human SH-SY5Ycells was examined by DAPI fluorescence staining and flow cytometry. Caspase-3, Bcl-2, Bax, Cyt-C, Akt, and P-Akt expression were detected by western blotting.


RESULTS
We found that exposure of SH-SY5Y to Aβ (25-35)-induced cytotoxicity, increased lactate dehydrogenase (LDH) leakage, and cellular apoptosis. Interestingly, pre-treatment with liraglutide reversed these reactions. Liraglutide afforded protection against Aβ (25-35)-induced toxicity by inhibiting apoptosis, which was also confirmed by the activated caspase-3 assay. P-Akt and Bcl-2/Bax expression increased after pre-treatment with liraglutide in SH-SY5Y cells exposed to Aβ (25-35), whereas cytochrome-c release decreased. This effect could be reversed by wortmannin, an inhibitor of PI3K (phosphoinositide 3-kinase).


CONCLUSIONS
These findings suggest that liraglutide prevented Aβ (25-35)-induced neurotoxicity by inhibiting neuronal apoptosis and liraglutide may have a neuroprotective effect through activation of the PI3K/Akt signaling pathway. Thus, liraglutide may be a preventive or therapeutic agent for Alzheimer's disease.
a Department of Endocrinology , Fujian Institute of Endocrinology, Union Hospital of Fujian Medical University , Fuzhou , People's Republic of China.|b Old Age Healthy Science Research Institute, Fujian Medical University , Fuzhou , People's Republic of China.
Xiao-Ying
XY
Liu
a Department of Endocrinology , Fujian Institute of Endocrinology, Union Hospital of Fujian Medical University , Fuzhou , People's Republic of China.|b Old Age Healthy Science Research Institute, Fujian Medical University , Fuzhou , People's Republic of China.
Lin-Xi
LX
Wang
c School of Pharmacology , Fujian Medical University , Fuzhou , People's Republic of China.
Zhou
Z
Chen
a Department of Endocrinology , Fujian Institute of Endocrinology, Union Hospital of Fujian Medical University , Fuzhou , People's Republic of China.|b Old Age Healthy Science Research Institute, Fujian Medical University , Fuzhou , People's Republic of China.
Li-Bin
LB
Liu
D016229:Amyloid beta-Peptides / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D019938:Cyclin D1 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007770:L-Lactate Dehydrogenase; D000069450:Liraglutide / Q000494:pharmacology*; D009447:Neuroblastoma / Q000473:pathology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D012844:Sincalide / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D016229:Amyloid beta-Peptides; D004791:Enzyme Inhibitors; D018696:Neuroprotective Agents; D010446:Peptide Fragments; C074636:amyloid beta-protein (25-35); D051028:bcl-2-Associated X Protein; D019938:Cyclin D1; D000069450:Liraglutide; D007770:L-Lactate Dehydrogenase; D019869:Phosphatidylinositol 3-Kinases; D020169:Caspases; D012844:Sincalide
Akt phosphorylation; Alzheimer’s disease; GLP-1 analogs; Neuroprotection; PI3K-dependent pathway