A complete Sigmodon hispidus genome and dynamic single-cell transcriptomics reveal evolutionarily conserved responses to RSV infection

The cotton rat ( Sigmodon hispidus ) has emerged as a preclinical model for human respiratory syncytial virus (RSV) research because of its ability to support effective viral replication and recapitulate disease; however, the mechanisms supporting this evolutionarily conserved phenotype remain unclear. Here, we report both the chromosomal genome and respiratory single-cell transcriptomic atlas of the cotton rat throughout the course of RSV infection. Phylogenetic analysis showed that cotton rats are in different evolutionary branches from common mouse and rat models and exhibit substantial conservation of tissue profiles with humans. The respiratory cell atlas, alveolar cell trajectory, and distribution of potential viral receptors are also similar to those of humans, explaining the superiority of cotton rats as an RSV infection model. The target cells of RSV, including club cells, secretory2 cells, mesothelial cells, and nerve-associated astrocytes, were expanded after infection. We also identified differential transcriptional regulators, specific antiviral proteins, and cytokines that could be translated into potential clinical markers in humans. Candidate host factors were also identified, which will enable the exploration of host-RSV interactions and offer a source of therapeutic targets.