title: Effect of all-trans retinoic acid (ATRA) on viability, proliferation, activation and lineage-specific transcription factors of CD4+ T cells.
abstract: All-trans retinoic acid (ATRA), as an active metabolite of vitamin A, has been shown to affect immune cells. This study was performed to evaluate the effect of ATRA on viability, proliferation, activation and lineage-specific transcription factors of CD4+ T cells. CD4+ T cells were separated from heparinized blood of healthy donors and were cultured in conditions, some with, some without ATRA. Viability was assessed by PI flowcytometry and proliferation was measured by MTT assay. CD69 expression was determined by flowcytometry as a measure of cell activation. Lineage-specific transcription factors (FOXP3, RORγt and T-bet) were examined by intracellular staining and flowcytometry. High doses of ATRA (0.1-1 mM) caused extensive cell death in both PBMCs and CD4+ T cells. Doses of ATRA equal to or lower than 10 µM did not adversely affect cell viability and proliferation in comparison to culture medium without ATRA. Doses of ATRA between 10 µM and 1nM significantly increased cell activation when compared to culture medium without ATRA. ATRA could increase FOXP3+ and also FOXP3+RORγt+ T cells while it decreased RORγt+ and T-bet+ T cells. This study showed that doses of ATRA up to 10 µM are safe when using with CD4+ T cells in terms of cell viability, proliferation and activation. We could also show that ATRA diverts the human immune response in neutral conditions (without adding polarizing cytokines) by increasing FOXP3+ cells and decreasing RORγt+ cells. ATRA could be regarded as a potential therapy in inflammatory conditions and autoimmunities.
authors.affiliation: Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Katayoon
authors.initials: K
authors.lastname: Bidad
authors.forename: Eisa
authors.initials: E
authors.lastname: Salehi
authors.forename: Mona
authors.initials: M
authors.lastname: Oraei
authors.forename: Ali-Akbar
authors.initials: AA
authors.lastname: Saboor-Yaraghi
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Nicknam
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000737:chemistry / Q000187:drug effects* / Q000276:immunology; D019070:Cell Lineage; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000032:analysis; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3 / Q000032:analysis; D020825:T-Box Domain Proteins / Q000032:analysis; D014212:Tretinoin / Q000494:pharmacology*; D000098815:T-bet Transcription Factor
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3; C539900:RORC protein, human; D020825:T-Box Domain Proteins; D000098815:T-bet Transcription Factor; D014212:Tretinoin