- Author:
Yong Bin HU
1
,
2
;
Xia WU
1
;
Xiao Feng QIN
3
;
Lei WANG
4
;
Pin Hua PAN
5
Author Information
- Publication Type:Journal Article
- Keywords: Alveolar macrophages; Apoptosis; Endoplasmic reticulum stress; Silica
- MeSH: Animals; Apoptosis; drug effects; Butylamines; Cell Survival; drug effects; Endoplasmic Reticulum Stress; physiology; Mice; RAW 264.7 Cells; Silicon Dioxide; toxicity
- From: Biomedical and Environmental Sciences 2017;30(8):591-600
- CountryChina
- Language:English
-
Abstract:
OBJECTIVEWe investigated the role of endoplasmic reticulum stress (ERS) in silica-induced apoptosis in alveolar macrophages in vitro.
METHODSRAW264.7 cells were incubated with 200 μg/mL silica for different time periods. Cell viability was assayed by the MTT assay. Cell apoptosis was evaluated by DAPI staining, flow cytometry analysis, and Western blot analysis of caspase-3. Morphological changes in the endoplasmic reticulum were observed by transmission electron microscopy. The expression of ERS markers binding protein (BiP) and CCAAT-enhancer-binding protein homologous protein (CHOP) was examined by Western blotting and real-time PCR. As an inhibitor of ERS, 4-phenylbutyric acid (4-PBA) was used in the experiments.
RESULTSSilica exposure induced nuclear condensation and caspase-3 expression in RAW264.7 cells. The number of apoptotic cells increased after silica exposure in a time-dependent manner. Silica treatment induced expansion of the endoplasmic reticulum. In addition, the expression of BiP and CHOP increased in silica-stimulated cells. Furthermore, 4-PBA treatment inhibited silica-induced endoplasmic reticulum expansion and the expression of BiP and CHOP. Moreover, 4-PBA treatment attenuated nuclear condensation, reduced apoptotic cells, and downregulated caspase-3 expression in silica-stimulated cells.
CONCLUSIONSilica-induced ERS is involved in the apoptosis of alveolar macrophages.