PROJECT SUMMARY (See instructions): Background: Adenovirus (Ad) infection normally induces mild, self-limited disease in immunocompetent human hosts. A new strain of Ad14, Ad14p1, first emerged in U.S. military and has since spread globally to civilian populations resulting in severe infections leading to acute respiratory distress syndrome (ARDS). We have shown that Ad that lacks expression of the E1B 20K (20K) gene results in dead cells (Ad CPE corpses) that stimulate a pro-inflammatory response from macrophages compared to an anti-inflammatory response from wild type Ad. Ad14p1 expresses only 20% the amount of 20K as the prototype Ad14 and results in Ad14p1 CPE corpses that are pro-inflammatory while prototype Ad14 CPE corpses are anti-inflammatory. Infection of Syrian hamsters (permissive for human Ad) showed a patchy bronchopneumonia following infection with Ad14p1 compared to little inflammation with Ad14. Hypothesis: 20K-dependent changes in miRNA expression regulate Ad CPE corpse immunomodulatory activity leads to increased pathogenesis. Specific Aims: 1. To refine and further develop the Syrian hamster model of Ad14p1 immunopathogenesis. 2. To determine the roles of alveolar macrophages and T-cells in Ad14p1 immunopathogenesis in the Syrian hamster. 3. To define the 20K expression threshold effect on Ad14p1 immunopathogenesis. 4. Define the expression of ‘Find Me’, ‘Eat Me’ and ‘Don’t Eat Me’ signal expression of Ad14/Ad14p1 CPE corpses and their roles in immunorepression. 5. Determine the role of increased expression of miR-181a-5p as the mediator of Ad14 CPE corpse repression on markers of pro-inflammatory responses: cytokine expression and M1/M2 macrophage polarization. Use of HPIC and Flow Cytometry facilities: Aims 1 and 2 will utilize the Syrian hamster model of Ad14p1 immunopathogenesis and will make extensive use of the HPIC for tissue fixation, embedding and sectioning, routine H&E, immunohistochemistry and pathological scoring of tissues to assess differences in disease pathology. All aims will make use of the Accuri C6 and MoFlo XDP that are available in the Flow Cytometry facility. Contribution to the Multi-disciplinary Infectious Diseases Research Program: Dr. Radke is a respected scientist in the field of adenoviruses and programmed cell death. His experience in adenoviruses and Ad14p1 will expand the core’s studies on infectious diseases to the viral pathogenesis while is interest in the innate immune response to virally infected and transformed cells will be in step with the core’s focus on the innate immune response to infectious diseases. In addition he will provide additional expertise in flow cytometry and molecular biology techniques to the core.