1 Department of Biology, PERFORM Centre, Concordia University, Montreal, Quebec, Canada.
2 Department of Psychology, PERFORM Centre, Concordia University, Montreal, Quebec, Canada.
3 Department of Chemistry and Biochemistry, PERFORM Centre, Concordia University, Montreal, Quebec, Canada.
4 Department of Biology, PERFORM Centre, Concordia University, Montreal, Quebec, Canada; Department of Psychology, PERFORM Centre, Concordia University, Montreal, Quebec, Canada; Department of Health, Kinesiology & Applied Physiology, PERFORM Centre, Montreal, Quebec, Canada. Electronic address: peter.darlington@concordia.ca.

Background: T helper 17 (Th17) cells produce IL-17A cytokine and can exacerbate autoimmune diseases and asthma. The ß2 adrenergic receptor is a g protein-coupled receptor that induces cAMP second messenger pathways. We tested the hypothesis that terbutaline, a ß2-adrenergic receptor-specific agonist, promotes IL-17 secretion by memory Th17 cells in a cAMP and PKA-dependent manner.

Methods: Venous peripheral blood mononuclear cells (PBMC) from healthy human participants were activated with anti-CD3 and anti-CD28 antibodies. Secreted IL-17A was measured by enzyme linked immunosorbent assay, intracellular IL-17A, and ROR? were measured using flow cytometry, and RORC by qPCR. Memory CD3⁺CD4⁺CD45RA^-CD45RO⁺ T cells were obtained by immunomagnetic negative selection and activated with tri-antibody complex CD3/CD28/CD2. Secreted IL-17A, intracellular IL-17A, RORC were measured, and phosphorylated-serine133-CREB was measured by western blotting memory Th cells.

Results: Terbutaline increased IL-17A (p < 0.001), IL-17A⁺ cells (p < 0.05), and RORC in activated PBMC and memory Th cells. The PKA inhibitors H89 (p < 0.001) and Rp-cAMP (p < 0.01) abrogated the effects of terbutaline on IL-17A secretion in PBMC and memory T cells. Rolipram increased IL-17A (p < 0.01) to a similar extent as terbutaline. P-Ser133-CREB was increased by terbutaline (p < 0.05) in memory T cells.

Conclusion: Terbutaline augments memory Th17 cells in lymphocytes from healthy participants. This could exacerbate autoimmune diseases or asthma, in cases where Th17 cells are considered to be pro-inflammatory.