Cathepsin L plays a role in quinolinic acid-induced NF-Κb activation and excitotoxicity in rat striatal neurons.
The present study seeks to investigate the role of cathepsin L in glutamate receptor-induced transcription factor nuclear factor-kappa B (NF-κB) activation and excitotoxicity in rats striatal neurons. Stereotaxic administration of the N-methyl-d-aspartate (NMDA) receptor agonist Quinolinic acid (QA) into the unilateral striatum was used to produce the in vivo excitotoxic model. Co-administration of QA and the cathepsin L inhibitor Z-FF-FMK or 1-Naphthalenesulfonyl-IW-CHO (NaphthaCHO) was used to assess the contribution of cathepsin L to QA-induced striatal neuron death. Western blot analysis and cathepsin L activity assay were used to assess the changes in the levels of cathepsin L after QA treatment. Western blot analysis was used to assess the changes in the protein levels of inhibitor of NF-κB alpha isoform (IκB-α) and phospho-IκB alpha (p-IκBα) after QA treatment. Immunohistochemical analysis was used to detect the effects of Z-FF-FMK or NaphthaCHO on QA-induced NF-κB. Western blot analysis was used to detect the effects of Z-FF-FMK or NaphthaCHO on QA-induced IκB-α phosphorylation and degradation, changes in the levels of IKKα, p-IKKα, TP53, caspase-3, beclin1, p62, and LC3II/LC3I. The results show that QA-induced loss of striatal neurons were strongly inhibited by Z-FF-FMK or NaphthaCHO. QA-induced degradation of IκB-α, NF-κB nuclear translocation, up-regulation of NF-κB responsive gene TP53, and activation of caspase-3 was strongly inhibited by Z-FF-FMK or NaphthaCHO. QA-induced increases in beclin 1, LC3II/LC3I, and down-regulation of p62 were reduced by Z-FF-FMK or NaphthaCHO. These results suggest that cathepsin L is involved in glutamate receptor-induced NF-κB activation. Cathepsin L inhibitors have neuroprotective effects by inhibiting glutamate receptor-induced IκB-α degradation and NF-κB activation.
Department of Pharmacology and Laboratory of Aging and Nervous Diseases (SZS0703), Soochow University School of Pharmaceutical Science, Wen Jing Road, Suzhou, China.
Yan-Ru
YR
Wang
Shu
S
Qin
Rong
R
Han
Jun-Chao
JC
Wu
Zhong-Qin
ZQ
Liang
Zheng-Hong
ZH
Qin
Yan
Y
Wang
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D056668:Cathepsin L / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D018698:Glutamic Acid / Q000378:metabolism; D007659:Ketones / Q000494:pharmacology; D008297:Male; D016328:NF-kappa B / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D059748:Proteolysis; D017378:Quinolinic Acid / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D015853:Cysteine Proteinase Inhibitors; D004151:Dipeptides; D007659:Ketones; D016328:NF-kappa B; D016194:Receptors, N-Methyl-D-Aspartate; D016159:Tumor Suppressor Protein p53; C057383:MDL 201053; D018698:Glutamic Acid; D056668:Cathepsin L; C534280:Ctsl protein, rat; D017378:Quinolinic Acid