TY - JOUR
T1 - Effects of select PM-associated metals on alveolar macrophage phosphorylated ERK1 and -2 and iNOS expression during ongoing alteration in iron homeostasis
AU - Prophete, Colette
AU - Maciejczyk, Polina
AU - Salnikow, Konstantin
AU - Gould, Timothy
AU - Larson, Timothy
AU - Koenig, Jane
AU - Jaques, Peter
AU - Sioutas, Constantinos
AU - Lippmann, Morton
AU - Cohen, Mitchell
PY - 2006/7/1
Y1 - 2006/7/1
N2 - It was hypothesized that relative mass relationships among select constituent metals and iron (Fe 3+ ) govern the pulmonary immunotoxic potential of any PM 2.5 sample, as these determine the extent to which Fe 3+ binding by transferrin is affected (resulting in altered alveolar macrophage [AM] Fe status and subsequent antibacterial function). Iron response protein (IRP) binding activity is a useful indirect measurement of changes in Fe status, as reductions in cell Fe levels lead to increases in IRP binding. However, AM IRP activity can be affected by an increased presence of nitric oxide generated by inducible nitric oxide synthase (iNOS). This study sought to determine if any changes in AM IRP activity induced by PM 2.5 constituents V, Mn, or Al were independent from effects of the metals on cell NO formation. NR8383 rat AM were exposed to Fe 3+ alone or combined with V, Mn, or Al at metal:Fe ratios representative of those in PM 2.5 collected in New York City, Los Angeles, and Seattle during fall 2001. Cells were then assessed for changes in IRP activity and iNOS expression. Phosphorylated extracellular signal-regulated kinase (ERK) 1 and 2 levels were also measured since activated ERKs are involved in signaling pathways that lead to increased iNOS expression. The results indicate that V and Al, and to a lesser extent Mn, altered IRP activity, though the effects were not consistently concentration dependent. Furthermore, while V and Mn treatments did not induce iNOS expression, Al did. These results confirmed our hypothesis that certain metals associated with PM 2.5 might alter the pulmonary immunocompetence of exposed hosts by affecting the Fe status of AM, a major class of deep lung defense cells. Copyright
AB - It was hypothesized that relative mass relationships among select constituent metals and iron (Fe 3+ ) govern the pulmonary immunotoxic potential of any PM 2.5 sample, as these determine the extent to which Fe 3+ binding by transferrin is affected (resulting in altered alveolar macrophage [AM] Fe status and subsequent antibacterial function). Iron response protein (IRP) binding activity is a useful indirect measurement of changes in Fe status, as reductions in cell Fe levels lead to increases in IRP binding. However, AM IRP activity can be affected by an increased presence of nitric oxide generated by inducible nitric oxide synthase (iNOS). This study sought to determine if any changes in AM IRP activity induced by PM 2.5 constituents V, Mn, or Al were independent from effects of the metals on cell NO formation. NR8383 rat AM were exposed to Fe 3+ alone or combined with V, Mn, or Al at metal:Fe ratios representative of those in PM 2.5 collected in New York City, Los Angeles, and Seattle during fall 2001. Cells were then assessed for changes in IRP activity and iNOS expression. Phosphorylated extracellular signal-regulated kinase (ERK) 1 and 2 levels were also measured since activated ERKs are involved in signaling pathways that lead to increased iNOS expression. The results indicate that V and Al, and to a lesser extent Mn, altered IRP activity, though the effects were not consistently concentration dependent. Furthermore, while V and Mn treatments did not induce iNOS expression, Al did. These results confirmed our hypothesis that certain metals associated with PM 2.5 might alter the pulmonary immunocompetence of exposed hosts by affecting the Fe status of AM, a major class of deep lung defense cells. Copyright
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U2 - 10.1080/15287390500362030
DO - 10.1080/15287390500362030
M3 - Article
C2 - 16728372
AN - SCOPUS:33745373358
VL - 69
SP - 935
EP - 951
JO - Journal of Toxicology and Environmental Health - Part A: Current Issues
JF - Journal of Toxicology and Environmental Health - Part A: Current Issues
SN - 1528-7394
IS - 10
ER -