Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 Jul 12;14(7):843.
doi: 10.3390/biom14070843.

Zinc Protects against Swine Barn Dust-Induced Cilia Slowing

Christopher D Bauer  1 , Deanna D Mosley  1 , Derrick R Samuelson  1 , Jill A Poole  2 , Deandra R Smith  3 , Daren L Knoell  3 , Todd A Wyatt  1   4   5
Affiliations

Zinc Protects against Swine Barn Dust-Induced Cilia Slowing

Christopher D Bauer et al. Biomolecules. .

Abstract

Agricultural workers exposed to organic dust from swine concentrated animal feeding operations (CAFOs) have increased chances of contracting chronic lung disease. Mucociliary clearance represents a first line of defense against inhaled dusts, but organic dust extracts (ODEs) from swine barns cause cilia slowing, leading to decreased bacterial clearance and increased lung inflammation. Because nutritional zinc deficiency is associated with chronic lung disease, we examined the role of zinc supplementation in ODE-mediated cilia slowing. Ciliated mouse tracheal epithelial cells were pretreated with 0-10 µg/mL ZinProTM for 1 h, followed by treatment with 5% ODE for 24 h. Cilia beat frequency (CBF) and protein kinase C epsilon (PKCε) activity were assayed. ODE treatment resulted in cilia slowing after 24 h, which was reversed with 0.5 and 1.0 µg/mL ZinPro pre-treatment. No zinc protection was observed at 50 ng/mL, and ciliated cells detached at high concentrations (100 µg/mL). ZinPro alone produced no changes in the baseline CBF and showed no toxicity to the cells at concentrations of up to 10 µg/mL. Pre-treatment with ZinPro inhibited ODE-stimulated PKCε activation in a dose-dependent manner. Based on ZinPro's superior cell permeability compared to zinc salts, it may be therapeutically more effective at reversing ODE-mediated cilia slowing through a PKCε pathway. These data demonstrate that zinc supplementation may support the mucociliary transport apparatus in the protection of CAFO workers against dust-mediated chronic lung disease.

Keywords: cilia; lung; organic dust; zinc.

PubMed Disclaimer

Conflict of interest statement

JAP received research regents (anti-IL-33/ST2 blocking antibody reagent, no money) from AstraZeneca, and JAP serves as a site recruiter for clinical industry studies for asthma, sinus disease, and urticaria (GlaxoSmithKline, AstraZeneca, Regeneron Pharmaceuticals, CellDex Therapeutics). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the Department of Veterans Affairs. The funders had no role in study design, data collection, and analysis; in the decision to publish the article; in the preparation of the manuscript; or in the decision to publish the results. The authors alone are responsible for the content of this manuscript.

Figures

Figure 1
Figure 1
Repetitive nasal instillation of organic dust extract (ODE) increases lung inflammation and decreases bacterial clearance. (A) Live animal microCT of the lung showing density in Hounsfield units (HUs) in mice at baseline followed by 3 weeks of 12.5% ODE (* p < 0.02, paired t-test of baseline vs. ODE for each mouse, n = 6). (B) S. pneumoniae lung burden at 48 h post infection in 12.5% ODE-treated mice (** p < 0.001, n = 6/group). (C) Total lung zinc content in mice repetitively instilled with sterile PBS or 12.5% ODE (n = 10).
Figure 2
Figure 2
ODE-induced slowing of ciliary beat frequency (CBF) in mouse tracheal epithelial cells (MTECs) is prevented by pretreatment with ZinPro. (A) Time course (0–24 h) of MTECs treated with 0–1 µg/mL ZinPro shows no effect on baseline CBF in Hertz (Hz). (B) Time course in the presence of 5% ODE (* p < 0.01 0–50 ng/mL vs. 500 ng/mL−1 µg/mL ZinPro; one-way ANOVA, n = 20).
Figure 3
Figure 3
ODE-induced activation of protein kinase C epsilon (PKCε) in mouse tracheal epithelial cells (MTECs) is prevented by pretreatment with ZinPro. (A) Time course (0–24 h) of MTECs treated with 1 µg/mL ZinPro in the presence or absence of 5% ODE (* p < 0.02 at 1 h ODE vs. media control; ** p < 0.003 at 6 h ODE vs. media control). (B) PKCε activity at 6 h with ±5% ODE and ±500 ng/mL ZinPro (* p < 0.01; ** p < 0.001; one-way ANOVA, n = 9).
Figure 4
Figure 4
Intracellular chelation of zinc blocks ZinPro reversal of ODE-induced cilia slowing. (A) Ciliated MTECs were pretreated for 4 h with or without 5 µM TPEN (N,N,N′,N′-Tetrakis-2-pyridylmethylethylenediamine), followed by 24 h of ±1 µg/mL ZinPro and ±5% ODE (* p < 0.01, ** p < 0.001, **** p < 0.0001 one-way ANOVA, n = 20). (B) No significant differences in the total number of moving cilia were observed with Chelexed media or TPEN treatment at the time of recording (24 h).
Figure 5
Figure 5
Intracellular chelation of zinc blocks ZinPro reversal of ODE-induced PKCε activation. Ciliated MTECs were pretreated for 1 h with or without 5 µM TPA (Tris(2-pyridylmethyl)amine) followed by 24 h of ±1 µg/mL ZinPro and ±5% ODE. (A) Cytosolic cell fraction measuring non-translocated PKC (** p < 0.001, **** p < 0.0001 one-way ANOVA). (B) Particulate cell fraction showing translocation-activated PKC (** p < 0.001, *** p < 0.005, **** p < 0.0001 one-way ANOVA, n = 9).
Figure 6
Figure 6
Zinc inhibits in vitro protein kinase C epsilon (PKCε) activity. (A) Purified PKCε treated with 0–1 mg/mL ZinPro in vitro (* p < 0.05; **** p < 0.0001, one-way ANOVA, n = 12). (B) Purified PKCε treated with 0–1 mg/mL ZnSO4 in vitro (**** p < 0.0001, one-way ANOVA, n = 9). (C) Purified PKCε treated with 0–1 mg/mL lysine and glutamic acid in vitro as a control. (D) Substrate-only negative control treated with 0–1 mg/mL ZinPro.
Figure 7
Figure 7
CBF is enhanced in isolated ciliary axonemes but not intact mouse tracheal cells or tissue. (A) Freshly excised mouse tracheal rings with beating cilia treated with ±10 µM ZnCl2. (B) Ciliated MTEC treated with ±10 µM ZnCl2. (C) De-membranated isolated ciliary axonemes activated with 1 mM ATP and treated with ±10 µM ZnCl2. (* p < 0.03 unpaired t-test, n = 12).
See this image and copyright information in PMC

References

    1. Heederik D., Sigsgaard T., Thorne P.S., Kline J.N., Avery R., Bonlokke J.H., Chrischilles E.A., Dosman J.A., Duchaine C., Kirkhorn S.R., et al. Health effects of airborne exposures from concentrated animal feeding operations. Environ. Health Perspect. 2007;115:298–302. doi: 10.1289/ehp.8835. - DOI - PMC - PubMed
    1. Clarke K., Manrique A., Sabo-Attwood T., Coker E.S. A Narrative Review of Occupational Air Pollution and Respiratory Health in Farmworkers. Int. J. Environ. Res. Public. Health. 2021;18:4097. doi: 10.3390/ijerph18084097. - DOI - PMC - PubMed
    1. Domingo N.G.G., Balasubramanian S., Thakrar S.K., Clark M.A., Adams P.J., Marshall J.D., Muller N.Z., Pandis S.N., Polasky S., Robinson A.L., et al. Air quality-related health damages of food. Proc. Natl. Acad. Sci. USA. 2021;118:2013637118. doi: 10.1073/pnas.2013637118. - DOI - PMC - PubMed
    1. Boissy R.J., Romberger D.J., Roughead W.A., Weissenburger-Moser L., Poole J.A., LeVan T.D. Shotgun pyrosequencing metagenomic analyses of dusts from swine confinement and grain facilities. PLoS ONE. 2014;9:e95578. doi: 10.1371/journal.pone.0095578. - DOI - PMC - PubMed
    1. Choinière Y., Munroe J. Farm Workers Health Problems Related to Air Quality Inside Livestock Barns. Ministry of Agriculture and Food; Guelph, ON, Canada: 1993.

LinkOut - more resources