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Dust from hog confinement facilities impairs Ca2+ mobilization from sarco(endo)plasmic reticulum by inhibiting ryanodine receptors.

Authors
Tian-C; Moore-CJ; Dodmane-P; Shao-CH; Romberger-DJ; Toews-ML; Bidasee-KR
Source
J Appl Physiol 2013 Mar; 114(5):665-674
NIOSHTIC No.
20043634
Abstract
Individuals working in commercial hog confinement facilities have elevated incidences of headaches, depression, nausea, skeletal muscle weakness, fatigue, gastrointestinal disorders, and cardiovascular diseases, and the molecular mechanisms for these nonrespiratory ailments remain incompletely undefined. A common element underlying these diverse pathophysiologies is perturbation of intracellular Ca(2+) homeostasis. This study assessed whether the dust generated inside hog confinement facilities contains compounds that alter Ca(2+) mobilization via ryanodine receptors (RyRs), key intracellular channels responsible for mobilizing Ca(2+) from internal stores to elicit an array of physiologic functions. Hog barn dust (HBD) was extracted with phosphate-buffered saline, sterile-filtered (0.22 m), and size-separated using Sephadex G-100 resin. Fractions (F) 1 through 9 (Mw >10,000 Da) had no measurable effects on RyR isoforms. However, F10 through F17, which contained compounds of Mw =2,000 Da, modulated the [(3)H]ryanodine binding to RyR1, RyR2, and RyR3 in a biphasic (Gaussian) manner. The Ki values for F13, the most potent fraction, were 3.8 +/- 0.2 g/ml for RyR1, 0.2 +/- 0.01 g/ml and 19.1 +/- 2.8 g/ml for RyR2 (two binding sites), and 44.9 +/- 2.8 g/ml and 501.6 +/- 9.2 g/ml for RyR3 (two binding sites). In lipid bilayer assays, F13 dose-dependently decreased the open probabilities of RyR1, RyR2, and RyR3. Pretreating differentiated mouse skeletal myotubes (C2C12 cells) with F13 blunted the amplitudes of ryanodine- and K(+)-induced Ca(2+) transients. Because RyRs are present in many cell types, impairment in Ca(2+) mobilization from internal stores via these channels is a possible mechanism by which HBD may trigger these seemingly unrelated pathophysiologies.
Keywords
Animals; Laboratory-animals; Airborne-dusts; Airborne-particles; Air-contamination; Metabolism; Pollution; Pollutants; Calcium-compounds; Dusts; Dust-exposure; Exposure-levels; Risk-factors; Humans; Men; Women; Muscles
Contact
Keshore R. Bidasee, 985800 Nebraska Medical Center, Durham Research Center, DRC 3047, Omaha, NE 68198-5800
CODEN
JAPHEV
CAS No.
7440-70-2; 7440-09-7
Publication Date
20130301
Document Type
Journal Article
Email Address
kbidasee@unmc.edu
Funding Type
Grant
Fiscal Year
2013
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-008539
Issue of Publication
5
ISSN
8750-7587
Priority Area
Agriculture, Forestry and Fishing
Source Name
Journal of Applied Physiology
State
NE
Performing Organization
University of Nebraska
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