A Preliminary Study towards Downregulation of Murine Bone Marrow Eosinophilopoiesis Mediated by Small Molecule Inhibition of Interleukin-5 Receptor α Gene in vitro

Abstract

Background: Bone marrow eosinophilopoiesis induced by IL-5 makes a major contribution to eosinophilic airway inflammation in asthma. Bone marrow CD₃₄⁺ cells expressing IL-5Rα may be eosinophil progenitors. However, research on the effect of blocking IL-5Rα expression on bone marrow eosinophilopoiesis has seldom been reported. Objective: To explore the effect of inhibiting IL-5Rα expression with IL-5Rα short hairpin RNA-expressing vector on murine bone marrow eosinophilopoiesisin vitro. Methods: We constructed 4 kinds of plasmid vectors that could express small molecule inhibition, short hairpin RNA, which targeted IL-5Rα (P-IL-5Rα), and selected an effective one by transfecting B lymphoma cells in vitro. We also constructed an adenovirus vector which was inserted into an effective template sequence (Ad-IL-5Rα). The bone marrow cells were obtained from healthy Balb/c mice, and cultured and transfected by Ad-IL-5Rα in vitro. The expression of IL-5Rα and the count of newly produced eosinophils were detected in the cultured bone marrow cells. Results: We found that P-IL-5Rα-3 targeted at the sequence of CAG CTG CCT GGT TCG TCT T markedly suppressed the IL-5Rα expression in the B lymphoma cellsin vitro. Ad-IL-5Rα could suppress the IL-5Rα expression of murine bone marrow cellsin vitro and it could also significantly decrease the IL-5-induced eosinophilia in the cultured bone marrow cells. Conclusion: These results indicate that the blocking of IL-5Rα expression by small molecule inhibition can help to effectively decrease murine bone marrow eosinophilopoiesis, and that bone marrow may be used as a critical target organ in the diseases involved in eosinophilia, such as asthma.