Cheow K Chang1, Joseph LoCicero. 1. Department of Surgery, Finch University of Health Sciences/The Chicago Medical School at Mount Sinai Hospital Medical Center, Chicago, Illinois, USA.
Abstract
BACKGROUND: Transcriptional regulation is a major determinant of interleukin-1beta (IL-1beta) protein synthesis. Nuclear factor kappaB (NF-kappaB) plays a central role in the regulation of IL-1beta and subsequent IL-1beta-dependent inflammatory processes. Previously, we observed in a murine endotoxic stress model a progressive increase with age in the amount of IL-1beta mRNA. We test the aging pulmonary response of NF-kappaB and NF-kappaB-dependent genes, IL-1beta, and inducible nitric oxide synthase (iNOS) in the same model. METHODS: Young (2-month-old) and senescent (25-month-old) mice were given 0.5 mg/kg lipopolysaccharide (LPS) intraperitoneally. Lung and blood samples were harvested after 4 hours. IL-1beta production in blood samples and the expression levels of protein and mRNA of IL-1beta and iNOS in lung tissues were measured. NF-kappaB binding activity in lung tissues was also determined. RESULTS: LPS induced higher levels of IL-1beta in the sera and lungs of senescent mice over young mice. Northern and Western blot analyses showed that mRNA and protein signals of IL-1beta and iNOS were significantly higher in old lungs than in young lungs. Electrophoretic mobility shift assay also showed that NF-kappaB activation was significantly higher in the older animals. CONCLUSIONS: Our results suggest that elevated activation of NF-kappaB, at least in part, contributes to the dysregulated expression of IL-1beta and iNOS in the lungs of senescent animals. Thus increased expression of proinflammatory cytokines and inflammatory responsive genes in the lung may play a role in the increased susceptibility in aging animals to endotoxic stress.
BACKGROUND: Transcriptional regulation is a major determinant of interleukin-1beta (IL-1beta) protein synthesis. Nuclear factor kappaB (NF-kappaB) plays a central role in the regulation of IL-1beta and subsequent IL-1beta-dependent inflammatory processes. Previously, we observed in a murine endotoxic stress model a progressive increase with age in the amount of IL-1beta mRNA. We test the aging pulmonary response of NF-kappaB and NF-kappaB-dependent genes, IL-1beta, and inducible nitric oxide synthase (iNOS) in the same model. METHODS: Young (2-month-old) and senescent (25-month-old) mice were given 0.5 mg/kg lipopolysaccharide (LPS) intraperitoneally. Lung and blood samples were harvested after 4 hours. IL-1beta production in blood samples and the expression levels of protein and mRNA of IL-1beta and iNOS in lung tissues were measured. NF-kappaB binding activity in lung tissues was also determined. RESULTS: LPS induced higher levels of IL-1beta in the sera and lungs of senescent mice over young mice. Northern and Western blot analyses showed that mRNA and protein signals of IL-1beta and iNOS were significantly higher in old lungs than in young lungs. Electrophoretic mobility shift assay also showed that NF-kappaB activation was significantly higher in the older animals. CONCLUSIONS: Our results suggest that elevated activation of NF-kappaB, at least in part, contributes to the dysregulated expression of IL-1beta and iNOS in the lungs of senescent animals. Thus increased expression of proinflammatory cytokines and inflammatory responsive genes in the lung may play a role in the increased susceptibility in aging animals to endotoxic stress.
Authors: Ti Zhou; Yang Hu; Ying Chen; Kevin K Zhou; Bin Zhang; Guoquan Gao; Jian-xing Ma Journal: Invest Ophthalmol Vis Sci Date: 2009-10-29 Impact factor: 4.799