Title : Synergistic nebulized therapy for severe viral pneumonia: A biomimetic nano-platform integrating MSC-derived exosomes and interferon-α2b
Abstract:
Background: Severe viral pneumonias, particularly those caused by influenza A virus, respiratory syncytial virus (RSV), and emerging coronaviruses, continue to pose formidable challenges to global public health. While Interferon-alpha (IFN-α) remains a cornerstone of antiviral therapy due to its potent induction of antiviral states in host cells, its clinical utility via traditional delivery routes is severely constrained. Systemic administration often triggers significant adverse effects, including bone marrow suppression and neurotoxicity. Conversely, direct nebulized inhalation of naked IFN-α proteins is hindered by rapid proteolytic degradation in the lung
microenvironment, poor retention in deep alveolar tissues, and loss of bioactivity during the high-shear nebulization process. There is an urgent clinical need for a delivery system that ensures both stability and localized therapeutic concentration.
Methods: In this study, we developed Exo-Aero α, a translational biomimetic nano-platform designed to overcome these barriers. Mesenchymal stem cell-derived exosomes (MSC-Exos) were isolated from P3-generation cells via ultracentrifugation and characterized as the primary delivery vehicle. Recombinant human IFN-α2b was encapsulated into the MSC-Exos using a proprietary physical-chemical loading and micro-extrusion protocol, optimizing the "Target- Treat-Repair" trinity logic. To facilitate large-scale distribution and clinical application, the formulation was engineered into a stable lyophilized powder using a specialized vacuumfreeze- drying process (10Pa/-50°C). The physicochemical properties, including particle size distribution (NTA), morphology (TEM), and post-nebulization bioactivity, were rigorously validated. Therapeutic efficacy was evaluated in a murine model subjected to a lethal-dose H1N1 viral challenge.
Results: The Exo-Aero α platform exhibited a highly uniform and stable particle size of 85.2 ± 21.6 nm, optimized for deep lung penetration. Post-nebulization analysis confirmed that the exosomal lipid bilayer provided robust physical shielding, maintaining over 95% of IFN-α2b biological activity. In vivo results demonstrated that the synergistic Exo-Aero α group achieved a remarkable 100% survival rate against lethal-dose H1N1 infection, significantly outperforming the IFN-α2b monotherapy group (32% survival) and the MSC-Exos group (60% survival). Mechanistic investigations revealed a profound "1+1>2" synergistic effect: IFN-α2b effectively suppressed viral replication via the JAK-STAT signaling pathway, while the MSC-Exos functioned as a potent immunomodulator, suppressing the pro-inflammatory "cytokine storm" and promoting the regeneration of damaged alveolar epithelial cells.
