Single-cell RNA sequencing (scRNA-seq) of skin from Rickettsia-infected and uninfected mouse

While the skin immune microenvironment orchestrates multifaceted defense strategies against diverse pathogens, the mechanisms by which obligate intracellular bacteria--particularly tick-borne spotted fever group rickettsiae (SFGR)--subvert cutaneous immunity to establish infection remain unresolved. Here, by integrating single-cell RNA sequencing (scRNA-seq) with a click chemistry-based SFGR labeling technique, we constructed a comprehensive cutaneous cell atlas of SFGR infection in wild-type, Ifnar1-/-, and double knockout Ifnar1-/-; Ifngr1-/- C57BL/6J mice. We found that monocyte-derived macrophages exhibit interferon-dependent responses, whereas recruited neutrophils respond to SFGR through interferon-independent oxidative stress, associated with elevated malondialdehyde (MDA) levels indicative of lipid peroxidation in rickettsia-infected mouse models. Together, these results advance our understanding of localized immune responses to obligate intracellular bacteria and provide a foundation for future mechanistic and therapeutic studies.