NLRP3 inflammasome expression in lipopolysaccharide-induced otitis media.

Abstract

BACKGROUND:

The nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome is a critical molecule mediating interleukin-1β (IL-1β) responses. However, the role of the NLRP3 inflammasome in otitis media has not been fully examined.

AIMS/OBJECTIVES:

The purpose of this study is to assess the expression of NLRP3, ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain and a pyrin domain), and caspase-1 in lipopolysaccharide-induced otitis media.

MATERIALS AND METHODS:

BALB/c mice received a transtympanic injection of either lipopolysaccharide or phosphate-buffered saline. The mice were sacrificed 24 h after injection. Concentrations of IL-1β, NLRP3, ASC, and caspase-1 in the middle ear effusions were measured by enzyme-linked immunosorbent assay. Temporal bones were processed for histologic examination and immunohistochemistry.

RESULTS:

The transtympanic injection of lipopolysaccharide significantly upregulated levels of IL-1β, NLRP3, ASC, and caspase-1 in the middle ear as compared with the control mice. The proteins of NLRP3, ASC, and caspase-1 were observed in infiltrating inflammatory cells induced by lipopolysaccharide in the middle ear cavity.

CONCLUSIONS AND SIGNIFICANCE:

Lipopolysaccharide induces NLRP3 inflammasome components in the middle ear. The NLRP3 inflammasome may play an important role in the pathogenesis of otitis media. Modulation of inflammasome-mediated inflammation may be a novel therapeutic strategy for otitis media.

• Authors: Shin Kariya, Mitsuhiro Okano, Pengfei Zhao, Yukihide Maeda, Yuko Kataoka, Takaya Higaki, Yohei Noda, Seiichiro Makihara, Kazunori Nishizaki
• Journal: Acta oto-laryngologica (Acta Otolaryngol) Vol. 138 Issue 12 Pg. 1061-1065 (Dec 2018) ISSN: 1651-2251 [Electronic] England
• PMID: 30676848 (Publication Type: Journal Article)

Chemical References

• CARD Signaling Adaptor Proteins
• Inflammasomes
• Inflammation Mediators
• Lipopolysaccharides
• NLR Family, Pyrin Domain-Containing 3 Protein
• Nlrp3 protein, mouse
• Pycard protein, mouse
• Caspase 1

Topics

• Animals
• Biopsy, Needle
• CARD Signaling Adaptor Proteins (metabolism)
• Caspase 1 (metabolism)
• Disease Models, Animal
• Immunohistochemistry
• Inflammasomes (metabolism)
• Inflammation Mediators (metabolism)
• Lipopolysaccharides (pharmacology)
• Mice
• Mice, Inbred BALB C
• NLR Family, Pyrin Domain-Containing 3 Protein (metabolism)
• Otitis Media (metabolism, pathology)
• Random Allocation
• Sensitivity and Specificity
• Statistics, Nonparametric
• Up-Regulation