Acute exposure to ozone (O3) causes upper and lower airway inflammation. We and others have previously demonstrated that O3 oxidizes lipids, particularly cholesterol, into electrophilic oxysterols, such as secosterol B (SecoB), which can adduct proteins, thus altering cellular signaling pathways. To investigate how O3-derived oxysterols influence cytokine and chemokine release, nasal epithelial cells (HNECs) from healthy donors (N = 18 donors) were exposed to 0.4ppm O3 for 4 hours. Afterward, immune mediators in apical washes and basolateral supernatants were analyzed using ELISAs, while sterol and oxysterol levels were examined using LC-MS. O3 exposure increased SecoB, 7-ketocholesterol (7Keto-Chol), 27-hydroxycholesterol (27OH-Chol), and epoxycholesterols in a sex-dependent manner. Female-derived HNECs had significant increases in SecoB, 27OH-Chol, and β-epoxycholesterol, while male-derived cells showed increases in 7Keto-Chol only. O3 decreased the release of Granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-7 but increased IL-1β, IL-6, IL-8, VEGF, and Eotaxin. Females exhibited O3-induced IL-1β and VEGF increases, while males showed increased Eotaxin and reduced GM-CSF. Basolaterally, O3 exposure decreased GM-CSF and TARC while raising IL-6, IL-13, IL- 1β, IL-8, and TNFα. Females showed higher TNFα and IL-1β, but males did not. Oxysterols correlated differently with cytokines by sex. Females showed positive correlations between oxysterols and pro52 inflammatory cytokines like IL-6 and IL-1β, while males displayed negative correlations with IL-6, IL-8, and TNFα. In conclusion, O3-induced cytokine/chemokine responses and sterol/oxysterol levels in HNECs vary by sex, with donor-specific oxysterols associated with O3-triggered inflammatory mediator release.
Keywords: cytokines; epithelial cells; oxysterol; ozone; sex differences.