title: Cystatin C induces apoptosis and tyrosine hydroxylase gene expression through JNK-dependent pathway in neuronal cells.
abstract: Cystatin C (CysC), an endogenous cysteine protease inhibitor, has been implicated in the apoptosis and differentiation processes of neuronal cells. In this study, we have investigated the pathway involved in the process. A human neuronal hybridoma cell line (A1 cell) was treated with CysC in both undifferentiated and retinoic acid (RA)-induced differentiated conditions, which decreased overall process length in both conditions. Also, CysC increased apoptotic cell number time-dependently, as revealed by TUNEL assay. Western blot analysis demonstrated that in differentiated A1 cells, CysC treatment decreased Bcl-2 and increased active caspase-9 protein level time-dependently. Immunocytochemistry results revealed that, CysC treatment significantly increased active form of Bax expressing cell number, which co-localized with mitochondria. Mitogen activated protein (MAP) kinase inhibition experiments showed that Bax mRNA induction and Bcl-2 mRNA inhibition by CysC treatment were c-Jun N-terminal kinase (JNK)-dependent. After RA-induced differentiation, choline acetyltransferase (ChAT) and neurofilament (NF) mRNA levels were increased in A1 cells. CysC treatment inhibited NF mRNA level in both undifferentiated and RA-differentiated, and increased TH mRNA in differentiated A1 neurons. Analysis of signal transduction pathway demonstrated that TH gene induction was also JNK-dependent. Thus, our results demonstrated the significance of JNK-dependent pathways on CysC-induced apoptosis and TH gene expression in neuronal cells, which might be an important target in the management of CysC dependent neurodegenerative processes.
authors.affiliation: Department of Laboratory Medicine, Shimane University Faculty of Medicine, 89-1 Enya-cho, Izumo 693-8501, Japan.
authors.forename: XueYun
authors.initials: X
authors.lastname: Liang
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nagai
authors.forename: Masaharu
authors.initials: M
authors.lastname: Terashima
authors.forename: Abdullah Md
authors.initials: AM
authors.lastname: Sheikh
authors.forename: Yuri
authors.initials: Y
authors.lastname: Shiota
authors.forename: Shingo
authors.initials: S
authors.lastname: Mitaki
authors.forename: Seung U
authors.initials: SU
authors.lastname: Kim
authors.forename: Shuhei
authors.initials: S
authors.lastname: Yamaguchi
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D002460:Cell Line; D055316:Cystatin C / Q000494:pharmacology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D048670:MAP Kinase Kinase 4 / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D011480:Protease Inhibitors / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
chemical_list: D055316:Cystatin C; D011480:Protease Inhibitors; D048670:MAP Kinase Kinase 4