Evidence of sex differences in ozone-induced oxysterol and cytokine levels in differentiated human nasal epithelial cells.

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 0.4 ppm O3 for 4 h. Afterward, immune mediators in apical washes and basolateral supernatants were analyzed using ELISAs, whereas sterol and oxysterol levels were examined using liquid-chromatography mass spectrometry (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, whereas 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 interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), VEGF, and Eotaxin. Females exhibited O3-induced IL-1β and VEGF increases, whereas males showed increased Eotaxin and reduced GM-CSF. Basolaterally, O3 exposure decreased GM-CSF and thymus and activation-regulated chemokine (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 proinflammatory cytokines like IL-6 and IL-1β, whereas 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.NEW & NOTEWORTHY It is increasingly recognized that lung biology and responses to pollutant exposures differ in males and females. Using a model of differentiated nasal epithelial cells from male and female donors, our data demonstrate that pollutant-induced cytokine/chemokine responses and oxidized lipid levels vary by sex, with donor-specific oxidized lipids linked to inflammatory mediator release.