Involvement of histone phosphorylation in apoptosis of human astrocytes after exposure to saline solution.
We have previously found using inhibitors of protein phosphatase that phosphorylation of histones may be involved in thymocyte apoptosis. In this study, we examined whether histone modification occurs in astrocyte apoptosis induced by a pathological condition in the absence of drug. Incubation of cultured human astrocytes with growth medium for 24 h after exposure to saline solution for 30 min induced an increase in terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells and nuclear condensation, biochemical and morphological hallmarks of apoptotic cell death. Acetic acid-urea-Triton X-100 (AUT) gel electrophoresis of the nuclear histone fraction and N-terminal peptide analysis showed that the treatment with saline solution caused rapid changes in phosphorylation of H2A subfamilies, but not in histone acetylation. The phosphorylation of the two subtypes increased markedly, whereas the phosphorylation of one subtype decreased. In contrast, exposure to ACF-95, an artificial cerebrospinal fluid (CSF), was associated with little induction of apoptotic cell death and induced less changes in histone phosphorylation. These results support the previous idea that chemical modification of histones is involved in the DNA fragmentation in astrocytes undergoing apoptosis.
Enomoto
Riyo
R
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Ikawadani-cho, Nishi-ku, Kobe 651-2180, Japan.
Tatsuoka
Hiroyuki
H
Komai
Tomoe
T
Sugahara
Chiyoko
C
Takemura
Kazu
K
Yamauchi
Aiko
A
Nishimura
Masuhiro
M
Naito
Shinsaku
S
Matsuda
Toshio
T
Lee
Eibai
E
D000595:Amino Acid Sequence; D017209:Apoptosis; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D020287:In Situ Nick-End Labeling; D008969:Molecular Sequence Data; D010766:Phosphorylation; D012965:Sodium Chloride
D006657:Histones; D012965:Sodium Chloride