Exosomal microRNA (miRNA) expression in Blonchoalveolar lavage fluid (BALF) collected from mice infected with influenza virus and inoculated with poly(I:C).

To clarify the profile of in BALF exosome collected from mice infected with influenza virus, we infected 100000 pfu of A/Puerto Rico/8/1934 (PR8) strain. BALF was collected at 24, 48, and 72 hour post infection (hpi). For comparison of the profile of the miRNA in BALF exosome induced by innate immune response, we also intranasally inoculated mice with 50 μg of poly(I:C) and collected BALF at 72 hour post inoculation. We found that some miRNAs were common to both influenza virus infectiona and poly(I:C) inoculation, suggesting that exosomal miRNAs in BALF may function in the innate immune response to virus infection. Each group had three biological replication. Exosome was isolated by using filteration and ultracentrifugation. BALF exosome isolated from naive mice was used as control. After isolation of total RNA, miRNA microarray was performed.