Intracellular accumulation dynamics and fate of zinc ions in alveolar epithelial cells exposed to airborne ZnO nanoparticles at the air-liquid interface

Airborne nanoparticles (NPs) that enter the respiratory tract are likely to reach the alveolar region. Accumulating observations support a role for zinc oxide (ZnO) NP dissolution in toxicity, but the majority of in-vitro studies were conducted in cells exposed to NPs in growth media, where large doses of dissolved ions are shed into the exposure solution. To determine the precise intracellular accumulation dynamics and fate of zinc ions (Zn(2+)) shed by airborne NPs in the cellular environment, we exposed alveolar epithelial cells to aerosolized NPs at the air-liquid interface (ALI). Using a fluorescent indicator for Zn(2+), together with organelle-specific fluorescent proteins, we quantified Zn(2+) in single cells and organelles over time. We found that at the ALI, intracellular Zn(2+) values peaked 3 h post exposure and decayed to normal values by 12 h, while in submerged cultures, intracellular Zn(2+) values continued to increase over time. The lowest toxic NP dose at the ALI generated peak intracellular Zn(2+) values that were nearly three-folds lower than the peak values generated by the lowest toxic dose of NPs in submerged cultures, and eight-folds lower than the peak values generated by the lowest toxic dose of ZnSO4 or Zn(2+). At the ALI, the majority of intracellular Zn(2+) was found in endosomes and lysosomes as early as 1 h post exposure. In contrast, the majority of intracellular Zn(2+) following exposures to ZnSO4 was found in other larger vesicles, with less than 10% in endosomes and lysosomes. Together, our observations indicate that low but critical levels of intracellular Zn(2+) have to be reached, concentrated specifically in endosomes and lysosomes, for toxicity to occur, and point to the focal dissolution of the NPs in the cellular environment and the accumulation of the ions specifically in endosomes and lysosomes as the processes underlying the potent toxicity of airborne ZnO NPs.

Medienart:

E-Artikel

Erscheinungsjahr:

2015

Erschienen:

2015

Enthalten in:

Zur Gesamtaufnahme - volume:9

Enthalten in:

Nanotoxicology - 9(2015), 1 vom: 23. Feb., Seite 9-22

Sprache:

Englisch

Beteiligte Personen:

Mihai, Cosmin [VerfasserIn]
Chrisler, William B [VerfasserIn]
Xie, Yumei [VerfasserIn]
Hu, Dehong [VerfasserIn]
Szymanski, Craig J [VerfasserIn]
Tolic, Ana [VerfasserIn]
Klein, Jessica A [VerfasserIn]
Smith, Jordan N [VerfasserIn]
Tarasevich, Barbara J [VerfasserIn]
Orr, Galya [VerfasserIn]

Links:

Volltext

Themen:

Air–liquid interface
Airborne nanoparticles
Endosomes
FluoZin-3
Intracellular Zn2+
J41CSQ7QDS
Journal Article
Lysosomes
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
SOI2LOH54Z
Zinc
Zinc Oxide

Anmerkungen:

Date Completed 28.12.2015

Date Revised 21.10.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.3109/17435390.2013.859319

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM233194401