ATP catabolism by tissue non-specific alkaline phosphatase contributes to development of ARDS in influenza-infected mice.

Influenza A viruses are highly contagious respiratory pathogens that are responsible for significant morbidity and mortality worldwide on an annual basis. We have shown previously that influenza infection of mice leads to increased ATP and adenosine accumulation in the airway lumen. Moreover, we demonstrated that A1-adenosine receptor activation contributes significantly to influenza-induced acute respiratory distress syndrome (ARDS). However, we found that development of ARDS in influenza-infected mice does not require catabolism of ATP to adenosine by ecto-5'-nucleotidase (CD73). Hence, we hypothesized that increased adenosine generation in response to infection is mediated by tissue non-specific alkaline phosphatase (TNAP), which is a low-affinity, high-capacity enzyme that catabolizes nucleotides in a non-specific manner. In the current study, we found that whole lung and BALF TNAP expression and alkaline phosphatase enzymatic activity increased as early as 2 days post infection (d.p.i.) of C57BL/6 mice with 10,000 pfu/mouse of influenza A/WSN/33 (H1N1). Treatment at 2 and 4 d.p.i. with a highly-specific quinolinyl-benzenesulfonamide TNAP inhibitor (TNAPi) significantly reduced whole lung alkaline phosphatase activity at 6 d.p.i. but did not alter TNAP gene or protein expression. TNAPi treatment attenuated hypoxemia, lung dysfunction, histopathology, and pulmonary edema at 6 d.p.i. without impacting viral replication. Treatment also improved epithelial barrier function and attenuated cellular and humoral innate immune responses to influenza infection. These data indicate that TNAP inhibition can attenuate influenza-induced ARDS by reducing inflammation and fluid accumulation within the lung. They also further emphasize the importance of adenosine generation for development of ARDS in influenza-infected mice.

from # All Medicine by Alexandros G. Sfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2krxiLS
via IFTTT