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Adenovirus infection increases iNOS and peroxynitrite production in the lung
Z K Zsengellér1, G F Ross, B C Trapnell
1Division of Neonatology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA.
Abstract:
Host inflammatory and immune responses limit viral gene expression after administration of replication-deficient adenoviruses to the lung. The current study asks whether inducible nitric oxide synthase (iNOS) expression and peroxynitrite generation accompanied the inflammatory response following intratracheal administration of adenovirus. Pulmonary iNOS mRNA and protein were increased 2, 7, and 14 days following administration of 2 x 10(9) plaque-forming units of recombinant adenovirus (Av1Luc1) to BALB/c mice. Adenovirus infection was associated with a marked increase in nitrotyrosine staining. Intense nitrotyrosine staining was observed in alveolar macrophages, respiratory epithelial cells, conducting airways, and alveolar spaces 2 days postinfection. Two weeks after exposure to adenovirus, nitrotyrosine staining was detected within alveolar macrophages, suggesting adenovirus enhanced the nitration of proteins that were subsequently taken up by alveolar macrophages. Western blot analysis using anti-nitrotyrosine antibody did not demonstrate accumulation of nitrated surfactant protein A (SP-A), although a small fraction of aggregated SP-A comigrated with a nitrotyrosine-positive protein. iNOS expression, peroxynitrite, and nitrotyrosine generation accompany and may contribute to inflammatory responses to adenovirus in the lung.
Insights
Host inflammatory responses to adenovirus in the lung involve inducible nitric oxide synthase (iNOS) and peroxynitrite generation. These factors may contribute to the overall inflammatory process following adenovirus administration.
Area of Science:
- Immunology
- Pulmonary Medicine
- Virology
Background:
- Host inflammatory and immune responses can limit viral gene expression from replication-deficient adenoviruses in the lung.
- Adenovirus vectors are used in gene therapy, and understanding their interaction with the host immune system is crucial.
Purpose of the Study:
- To investigate the role of inducible nitric oxide synthase (iNOS) expression and peroxynitrite generation in the pulmonary inflammatory response after intratracheal administration of adenovirus.
- To determine if adenovirus infection leads to increased nitrotyrosine staining, an indicator of peroxynitrite activity.
Main Methods:
- BALB/c mice were administered a recombinant adenovirus (Av1Luc1) intratracheally.
- Pulmonary iNOS mRNA and protein levels were measured at 2, 7, and 14 days post-administration.
- Nitrotyrosine staining was assessed in lung tissues using immunohistochemistry and Western blot analysis.
Main Results:
- Pulmonary iNOS mRNA and protein significantly increased at 2, 7, and 14 days after adenovirus administration.
- A marked increase in nitrotyrosine staining was observed in various lung cells and spaces, particularly at 2 days postinfection.
- Nitrotyrosine staining persisted in alveolar macrophages at 14 days, suggesting uptake of nitrated proteins.
Conclusions:
- Inducible nitric oxide synthase (iNOS) expression and peroxynitrite generation are associated with the pulmonary inflammatory response to adenovirus.
- These findings suggest that iNOS-derived peroxynitrite may play a role in mediating adenovirus-induced lung inflammation.