Korean J Intern Med.  2017 Sep;32(5):865-874. 10.3904/kjim.2016.033.

The activation of NLRP3-inflammsome by stimulation of diesel exhaust particles in lung tissues from emphysema model and RAW 264.7 cell line

• Uh ST
• Koo SM
• Kim Y
• Kim K
• Park S
• Jang AS
• Kim D
• Kim YH
• Park CS

• KMID: 2411489
• DOI: http://doi.org/10.3904/kjim.2016.033

Abstract

BACKGROUND/AIMS
Diesel exhaust particles (DEPs) lead to elevation of reactive oxygen species, which can activate the nucleotide-binding oligomerization domain-like receptor (NLR) family members containing the pyrin domain 3 (NLRP3)-inf lammasome. In this study, we elucidated whether NLRP3 -inf lammasome is activated by DEPs and whether antioxidants (N-acetylcysteine [NAC]) could inhibit such activation.
METHODS
RAW 264.7 cells and ex vivo lung tissues explants obtained from elastase-induced emphysema animal models were stimulated with cigarette smoking extract (CSE), DEPs, and lipopolysaccharide, and levels of interleukin-1β (IL-1β), caspase-1 and nucleotide-binding oligomerization domain-like receptor (NLR) family members containing the pyrin domain (NLRP3)-inflammasome were assessed by Western blotting and immunohistochemistry.
RESULTS
NAC and caspase-1 inhibitor suppressed CSE- and DEP-induced secretion of IL-1β in RAW 264.7 cells. The expression levels of the NLRP3-inflammasome and caspase-1 were upregulated in RAW 264.7 cells by stimulation with CSE and DEPs and were inhibited by NAC. CSE and DEPs increased the secretion of IL-1β in lung tissues from both the normal and elastase-induced emphysema groups. The secretion of IL-1β by CSE and DEPs was increased in the elastin-induced emphysema group more than that in the normal group (CSE: 309 ± 19 pg/mL vs. 151 ± 13 pg/mL, respectively, p < 0.05; DEP: 350 ± 24 pg/mL vs. 281 ± 15 pg/mL, respectively, p < 0.05). NAC inhibited CSE- and DEP-induced IL-1β secretion in both the normal and elastase-induced emphysema groups. NLRP3-inflammasome expression as determined by immunohistochemistry was increased by CSE and DEPs in both the normal and elastin-induced emphysema groups, and was suppressed by NAC.
CONCLUSIONS
The NLRP3-inf lammasome is activated by DEPs in ex vivo tissue explants from elastase-induced emphysema animal model, and this activation is inhibited by NAC.

Keyword

Pulmonary disease, chronic obstructive; Emphysema; Inf lammasomes; Vehicle emissions; Pancreatic elastase

MeSH Terms

Antioxidants
Blotting, Western
Emphysema*
Humans
Immunohistochemistry
Lung*
Models, Animal
Pancreatic Elastase
Pulmonary Disease, Chronic Obstructive
RAW 264.7 Cells*
Reactive Oxygen Species
Smoking
Vehicle Emissions*
Antioxidants
Pancreatic Elastase
Reactive Oxygen Species
Vehicle Emissions