NanoString autoimmune profiling panel normalized linear counts and summary of statistical analyses

Occupational exposure to respirable crystalline silica (cSiO2) is linked to the development of lupus. Preclinical studies have revealed weekly repeated intranasal exposure to 1 mg cSiO2 in young (8-11 wk-old) female NZBWF1 lupus-prone mice, a life-stage equivalent to 12–20-yr-old humans, triggers autoimmunity in the lungs and kidneys that is prevented by dietary supplementation with the omega-3 fatty acid docosahexaenoic acid (DHA). Methods: Here, we characterized cSiO2's and DHA's effects in mature adult (16–19-wk-old) female NZBWF1 mice, an age period that coincides with the onset of immunological tolerance breach and that is more representative of the age (>20-yr-old) of cSiO2-exposed workers. We fed mice either a control diet (CON) or diet amended with DHA calorically equivalent to a human daily dose of 5 g. After 2 wk, we intranasally instilled them with either saline vehicle (VEH) or 1 mg of cSiO2 weekly for 4 wk. Cohorts were terminated 1 and 5 wk after the final installation. Lungs were then analyzed for inflammatory cell counts, chemokines, histopathology, B-and T-cell infiltration, autoantibody profile, and inflammatory/autoimmune gene signatures and results further related to autoimmune glomerulonephritis onset. Results: VEH/CON mice displayed no lung or kidney pathology at either time point. In contrast, cSiO2/CON mice exhibited mild ectopic lymphoid tissue (ELT) formation in the lungs at 1 wk, which increased significantly by 5 wk. Lungs from cSiO2/CON mice also showed elevations in BALF cellularity, chemokine production, CD3 + T-cells, CD45R + B-cells, IgG + plasma cells, inflammatory/autoimmune gene expression, IgG autoantibodies. cSiO2/CON mice had visible glomerular hypertrophy and IgG deposition. Dietary DHA supplementation suppressed all these endpoints. Discussion: Consistent with young mice, intranasal cSiO2 exposure in mature adult NZBWF1 lupusprone mice elicited early pulmonary inflammation that served as a nexus for autoimmunity, suggesting these life-stage differences are not critical for cSiO2-triggered autoimmune response in this preclinical model. DHA supplementation at a translationally relevant human dosage effectively mitigated cSiO2-induced inflammation/autoimmunity in mature adult mice, resembling the protective effects observed in young mice. Together these findings further highlight the therapeutic potential of omega-3 fatty acids in mitigating toxicant-triggered autoimmune responses.