Use of 25(OH) cholecalciferol to inhibit the production of inflammatory cytokines by immune cells

Systemic Lupus Erythematosus (SLE) is an autoimmune inflammatory disease, characterized by the presence of autoantibodies against nucleic acids and ribonuclear proteins. These induce chronic inflammation and the production of numerous cytokines responsible for many symptoms in SLE patients. Vitamin D is an important immunomodulating agent that downregulates cytokine production under inflammatory conditions. Most in vitro studies involving vitamin D use the active form of the secosteroid, 1,25 (OH)2 cholecalciferol. This form cannot be administered as treatment because it increases calcemia whereas the storage form of Vitamin D, 25(OH) cholecalciferol, does not. The aim of this research is to determine whether 25(OH) cholecalciferol will downregulate cytokine production in different immune cell subpopulations. Induction of the inflammatory response results in the upregulation of CP27B1, an enzyme that hydroxylates the storage form of Vitamin D, converting it to the active form. It was expected that 25(OH) cholecalciferol would inhibit cell proliferation in Jurkat T cells, after PHA (Phytohaemagglutinin P), an agent that stimulates T-cell proliferation, was added. Cells were harvested and analyzed using flow cytometry. Jurkat cells do not express the Vitamin D receptor; therefore, 25(OH) cholecalciferol was not able to attach to a receptor to modulate the immune response. Treatment with LPS (lipopolysaccharide), an agent used to stimulate macrophages, was used to activate the THP-1 cells. Cells were permeabilized, stained with anti TNFɑ–PE, and analyzed using flow cytometry. 25(OH) cholecalciferol was successful in downregulating TNFɑ production in LPS stimulated macrophages. Future studies will be conducted using varying concentrations of 25(OH) cholecalciferol.