; University of Michigan Medical School
Dr. Ulus Atasoy is a physician scientist and Associate Professor of Internal Medicine in the Division of Allergy-Immunology at the University of Michigan, Section Chief of Allergy-Immunology and Director of the Allergy-Immunology Fellowship Program at the Ann Arbor VA Medical Center. He obtained his undergraduate degree from Rutgers University (Physics and Philosophy) and completed graduate and medical Studies at the University of Minnesota. Upon completion of Pediatrics Residency (UCLA), he joined the laboratory of Dr. William Paul (NIH) as a postdoctoral fellow and studied T cell immunology. He completed clinical and scientific training at Duke Medical Center (Dr. Louise Markert, Dr. Jack Keene) and joined the faculty at Duke University and University of Missouri, prior to relocating to the University of Michigan. He cloned murine HuR (Elavl1) and participated in the development of RNA immunoprecipitation techniques (RIP-seq) in the Keene laboratory. Dr. Atasoy鈥檚 laboratory has investigated posttranscriptional regulation of CD4+ T cell differentiation and its role in the pathogenesis of allergen driven airway inflammation and asthma, using genetically engineered murine models, as well as human translational approaches.
Background: Persistent Th2 inflammation in allergic asthma is maintained by post-transcriptional stabilization of mRNAs encoding GATA3 and downstream cytokines. RNA-binding protein HuR (ELAVL1) regulates these transcripts, suggesting its inhibition may attenuate Th2 responses. We previously demonstrated that T cell-specific HuR conditional ablation in mice (distal lck cre HuRfl/fl) inhibited allergic airway inflammation, highlighting its essential role in regulating CD4鈦 T cell differentiation and Th2 cytokine expression.
Objective: We hypothesized that KH-3, a small-molecule HuR inhibitor, would reduce GATA3 mRNA stability and thereby Th2 cytokine expression in murine and human lung CD4鈦 T cells.
Methods: We used murine and human platforms to investigate effects of HuR inhibition. Mice were immunized using the physiologically relevant antigen, house dust mite (HDM). Human lung tissue was digested with collagenase and CD4鈦 T cells were isolated using anti-CD4 magnetic beads and column separation. Cells were pretreated for 2 hours with KH-3 or inactive analog KH-3B, then activated with plate-bound anti-CD3/CD28 antibodies for 4 days. In parallel, HDM-challenged mice were treated with in vivo injections of KH-3. Cytokine secretion was quantified by Luminex assay. mRNA decay (actinomycin-D) and steady-state transcript levels were evaluated by RT-qPCR.
Results: KH-3 treatment ameliorated lung cellular infiltration, cytokine secretion as well as airway hyperresponsiveness (AHR) in HDM- treated mice. KH-3 significantly reduced secretion of IL-4, IL-5, and IL-13 versus KH-3B while IL-10, IL-2, and IL-1尾 levels were unchanged. Actinomycin-D data showed accelerated decay and lower steady-state levels of GATA3 and Th2 cytokine mRNAs in KH-3鈥搕reated cells, indicating reduced mRNA stability from HuR inhibition. mRNA stability of ROR纬t and T-bet remained unchanged.
Conclusion: HuR inhibition by KH-3 disrupts posttranscriptional maintenance of GATA3 and Th2 cytokine mRNAs in both murine and human lung CD4鈦 T cells. These findings identify HuR as a central regulator of Th2 effector responses and support its targeting as a potential therapeutic strategy for allergic asthma.
Event Time & Dates
Event Details