P15 Polyunsaturated fatty acids enhance cell death in Jurkat T cells: implications for dysregulated cell death pathways in skin disease
Michelle Allen, Anna Nicolaou, Alexandra Kendall, Amy Saunders, Silvia Bulfone-PausAbstract
Introduction and aims
Psoriasis is an inflammatory skin condition with increased inflammatory cell death (ferroptosis and pyroptosis) and reduced noninflammatory cell death (apoptosis). Resident and infiltrating cutaneous T cells metabolize fatty acids (FAs) into inflammatory or anti-inflammatory lipid mediators; their production is altered in psoriasis skin. We aim to explore how these lipids may influence different cell death pathways.
Methods
Naïve and anti-CD3/CD28-activated Jurkat T cells were treated with arachidonic acid (AA), linoleic acid (LA), docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) or palmitic acid (PA) (0–100 µmol L–1; 24 h) and viability assessed by CCK8. To explore whether FAs enhance or protect against cell death, naïve Jurkat T cells were treated with AA, LA, PA, DHA or EPA (20 μmol L–1; 24 h) to generate FA-loaded cells and divided into two groups. Group one were activated (anti-CD3/CD28) and then exposed to cell death inducers (dox, 0.15 μmol L–1; erastin, 5 μmol L–1; nigericin, 1.5 μmol L–1). Group two remained naïve and treated with FAs only (24 h), before exposure to cell death inducers (24 h). Cells were then stained with anti-CD69 and Zombie near-infrared (NIR) (activated) or Zombie NIR (naïve), before fixing and assessing using flow cytometry.
Results
Polyunsaturated FAs (AA, LA, DHA and EPA) reduced viability (< 80%) in activated and naïve Jurkat T cells. PA (saturated FA) did not induce cell death in naïve or activated T cells, but specifically sensitized cells to erastin-induced ferroptosis. AA, LA, DHA and EPA all enhanced dox-induced apoptosis, erastin-induced ferroptosis and nigericin-induced pyroptosis.
Conclusions
Polyunsaturated FAs enhanced inflammatory (ferroptosis and pyroptosis) and noninflammatory (apoptosis) cell death, while the saturated FA, PA, enhanced only erastin-induced ferroptosis. PA cannot be metabolized to lipid mediators through the same pathways as polyunsaturated FAs suggesting it could initiate cell death through alternative mechanisms. Pretreating T cells with FAs may sensitize them to pharmacological treatments enhancing their efficacy and improving therapeutic potential.