Comparative proteomics of inhaled silver nanoparticles in healthy and allergen provoked mice

Abstract

Background: Silver nanoparticles (AgNPs) have been associated with the exacerbation of asthma; however, the immunological basis for the adjuvant effects of AgNPs is not well understood.

Objective: The aim of the study reported here was to investigate the allergic effects of AgNP inhalation using proteomic approaches.

Methods: Allergen provoked mice were exposed to 33 nm AgNPs at 3.3 mg/m(3). Following this, bronchoalveolar lavage fluid (BALF) and plasma were collected to determine protein profiles.

Results: In total, 106 and 79 AgNP-unique proteins were identified in the BALF of control and allergic mice, respectively. Additionally, 40 and 26 AgNP-unique proteins were found in the plasma of control and allergic mice, respectively. The BALF and plasma protein profiles suggested that metabolic, cellular, and immune system processes were associated with pulmonary exposure to AgNPs. In addition, we observed 18 proteins associated with systemic lupus erythematosus that were commonly expressed in both control and allergic mice after AgNP exposure. Significant allergy responses were observed after AgNP exposure in control and allergic mice, as determined by ovalbumin-specific immunoglobulin E.

Conclusion: Inhaled AgNPs may regulate immune responses in the lungs of both control and allergic mice. Our results suggest that immunology is a vital response to AgNPs.

Keywords: bronchoalveolar lavage; immunotoxicology; proteome; serum; systemic lupus erythematosus.

Figure 1

Experimental design for investigating the effects of silver nanoparticles (AgNPs) on the allergic response to ovalbumin (OVA) antigen using proteomic approaches. OVA: OVA in aluminum hydroxide adjuvant prepared in phosphate-buffered saline (PBS); PBS (control): aluminum hydroxide adjuvant prepared in PBS. Abbreviation: HEPA, high-efficiency particulate air.

Figure 2

Scanning electron microscopy images of (A) the blank Teflon substrate and (B) silver nanoparticles (AgNPs) collected on the Teflon substrate at 5,000× and (C and D) 50,000× magnification.

Figure 3

Venn diagrams showing the proteins common or unique to silver nanoparticle (AgNP) treatment. (A) Bronchoalveolar lavage fluid (BALF) proteins in control mice, (B) BALF proteins in allergic mice, (C) plasma proteins in control mice, and (D) plasma proteins in allergic mice. The identified AgNP-unique proteins were further analyzed for commonalities in control and allergic mice after AgNP exposure. (E) Proteins commonly expressed in BALF and (F) proteins commonly expressed in plasma. Abbreviation: FA, filtered air.

Figure 4

Biological process in (A) bronchoalveolar lavage fluid (BALF) and (B) plasma obtained using Protein ANalysis THrough Evolutionary Relationships (PANTHER) analysis.

Figure 5

Pathway analysis in (A) bronchoalveolar lavage fluid (BALF) and (B) plasma protein using Protein ANalysis THrough Evolutionary Relationships (PANTHER) analysis. Abbreviation: TCA cycle, tricarboxylic acid cycle.

Figure 6

Ovalbumin (OVA)-specific immunoglobulin (Ig) E was collected from control and allergic mice 1 day before and 2 days after silver nanoparticle (AgNP)/filtered air (FA) inhalation and OVA challenge. Note: Values are expressed as the means ± standard deviation; n = 5–6. *P < 0.05.