Glycan-Mediated Impacts on the Mucus Barrier Towards Respiratory Viruses

/ ABSTRACT The mucus barrier in the lung provides a critical, first-line defense system that acts to trap and remove inhaled particulates. To cause infection, viruses must overcome this barrier to avoid elimination from the respiratory tract. Thus, understanding the elements that constitute a functional mucus barrier and the specific nature of virus- mucus interactions is paramount. Prior work investigating the mechanisms by which respiratory viruses such as influenza A virus (IAV) are neutralized by the mucus barrier in the lung has primarily focused on virus trapping through adhesive interactions. However, our preliminary data suggest penetration of IAV through the mucus barrier can be largely attributed to the architecture of mucus that leads to viral particle size -dependent physical trapping. Moreover, it remains unclear how the mucus barrier protects the lung against other respiratory viruses with and without the capacity to bind mucin-associated glycans. We propose a conceptually innovative central hypothesis that physical trapping of viruses by the mucus barrier is glycan dependent and provides a broadly conserved protective mechanism to neutralize diverse respiratory viruses. This hypothesis will be tested by pursuing two specific aims where we will determine 1) how mucin-associated glycans dictate structural mucus properties and mucociliary clearance (MCC) and 2) how specific secreted mucins and mucin-associated glycans dictate virus trapping and infection dynamics by diverse respiratory viruses including IAV, rhinovirus, respiratory syncytial virus, human metapneumovirus, human parainfluenza virus 3, and adenovirus. To achieve these objectives, we will utilize genetically-modified models of human airway epithelium lacking specific secreted mucin proteins, or deficient in fucosylation, sialylation, or sulfation. This approach is technically innovative and will be paired with biophysical assays to quantify virus-mucus interactions and real-time dynamics of mucus clearance function to provide mechanistic understanding of observed viral infection phenotypes. Together, this work will further clarify the impact of mucus, mucins, and their associated glycans on host-pathogen interactions critical to protection against respiratory virus infection. If successful, the results of this work will be significant given such knowledge will inform our understanding of viral transmission and susceptibility to infection and provide mechanistic insights which could potentially explain the deficits in antiviral functions observed clinically in chronic lung diseases. Project Number: 1R01HL182101-01 | Fiscal Year: 2025 | NIH Institute/Center: National Heart Lung and Blood Institute (NHLBI) | Principal Investigator: Margaret Scull (+1 co-PI) | Institution: UNIV OF MARYLAND, COLLEGE PARK, COLLEGE PARK, MD | Award Amount: $711,144 | Activity Code: R01 | Study Section: Special Emphasis Panel[ZRG1 RCCS-N (03)] View on NIH RePORTER: https://reporter.nih.gov/project-details/1R01HL18210101