A spatial sequencing atlas of age-induced changes in the lung during influenza infection - Summary
Respiratory viral infection, such as seasonal flu and COVID pandemic, has a significant impact on global health.
Influenza virus epidemics result in severe illness, hospitalizations, and deaths, especially among elderly people.
Aging is associated with a decline in immune function, making older adults more susceptible to severe flu
symptoms and complications. Understanding the underlying mechanisms of age-associated immune responses
in flu is crucial for developing effective prevention and treatment strategies. The baseline increase in
inflammation, often referred to as inflammaging, is a major driver of age-related pathophysiological changes.
Murine models of aging have been shown to have qualitatively and quantitively impaired anti-influenza immune
responses: aged lungs exhibit altered myeloid cell recruitment and function; lower titers of neutralizing
antibodies; and delayed and diminished recruitment of CD4 and CD8 T cells to the lung during infection, which
results in delayed viral clearance. Aging alters all organ systems, not just the immune system; as such, aging
may also impact the host response to Influenza A virus (IAV) through direct changes in lung tissue. Nevertheless,
little is known about how immune cells interact with epithelial and endothelial cells in the lung and how these
interactions contribute to the host defense, tissue injury, wound healing in the lung and coagulopathy
systemically with aging. Previously published research from the team and others demonstrate that aged immune
cells drive a senescent phenotype in non-immune tissues, and that a subset of type 2 innate lymphoid cells
(ILC2s) promotes wound healing and tissue repair in the lung following IAV infection. These observations
highlight the importance of crosstalk among immune, epithelial, and endothelial cells during infection, which also
demand new methodology to more comprehensively investigate the colocalization of these cellular components.
New spatial sequencing techniques, such as the 10x Genomics Visium platform, offer the ability to identify cells
and their gene expression profiles in situ at a resolution not previously possible, particularly when paired with
scRNA-seq. Therefore, the team seek to utilize a combination of scRNA-seq, spatial sequencing, and bulk RNA-
seq to generate a multifaceted, high-resolution atlas of young and aged lung tissue following influenza infection
and identify key changes induced by aging in this clinically relevant setting in this proposed study. Using
advanced computational algorithms, the team will further delineate how lung epithelial cells affect the migration
and tissue retention of immune cells, how immune cells trigger tissue repair and endothelial cell activation and
coagulation, and how novel molecular pathways affect inflammation and fibrosis in the resolution phase of
infection in the proposed study. Overall, the team anticipate that our project will identify potential targets for the
development of new therapeutic strategies to prevent and treat severe flu symptoms in elderly people.
