Convergent hub pathways targeted by IAV, SARS-CoV-2, and RSV in type II alveolar epithelial cells: molecular mechanisms and therapeutic implications.

Type II alveolar epithelial cells (AEC2s) maintain surfactant homeostasis, support distal-lung repair, and contribute to antiviral innate defense. Influenza A virus (IAV), SARS-CoV-2, and respiratory syncytial virus (RSV) use distinct entry receptors, yet severe disease is repeatedly marked by AEC2 dysfunction, alveolar barrier failure, and dysregulated inflammation. We synthesize cross-virus evidence for convergence on a small set of host hubs: innate sensing and interferon signaling, mitochondria-centered immunometabolism and oxidative stress, post-translational signaling modules, barrier and surfactant programs, and regulated cell-death checkpoints. We summarize structural and post-translational mechanisms by which viral proteins disrupt pattern recognition receptor (PRR)-mitochondrial antiviral signaling protein (MAVS) signaling, couple mitochondrial injury to weakened antiviral responses, and bias epithelial fate toward inflammatory lytic injury. Where AEC2-specific evidence is incomplete, especially for integrated PANoptosis-like programs, we label these elements as working models and highlight validation needs. We compare model systems used to study AEC2 infection, including ALI cultures, organoids, lung-on-chip platforms, and single-cell or network analyses. Finally, we discuss host-directed therapeutic opportunities along the cascade, separating near-term approaches from longer-term platform strategies such as targeted protein degradation and targeted nanodelivery, and noting constraints in distal-lung delivery, onset kinetics, and safety. This AEC2-centered convergence framework supports mechanism-driven interpretation of severe viral pneumonia and guides broader-spectrum intervention concepts.