A preliminary study towards downregulation of murine bone marrow eosinophilopoiesis mediated by small molecule inhibition of interleukin-5 receptor alpha gene in vitro.

BACKGROUND

Bone marrow eosinophilopoiesis induced by IL-5 makes a major contribution to eosinophilic airway inflammation in asthma. Bone marrow CD(34)(+) cells expressing IL-5Ralpha may be eosinophil progenitors. However, research on the effect of blocking IL-5Ralpha expression on bone marrow eosinophilopoiesis has seldom been reported.

OBJECTIVE

To explore the effect of inhibiting IL-5Ralpha expression with IL-5Ralpha 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-5Ralpha (P-IL-5Ralpha), 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-5Ralpha). The bone marrow cells were obtained from healthy Balb/c mice, and cultured and transfected by Ad-IL-5Ralpha in vitro. The expression of IL-5Ralpha and the count of newly produced eosinophils were detected in the cultured bone marrow cells.

RESULTS

We found that P-IL-5Ralpha-3 targeted at the sequence of CAG CTG CCT GGT TCG TCT T markedly suppressed the IL-5Ralpha expression in the B lymphoma cellsin vitro. Ad-IL-5Ralpha could suppress the IL-5Ralpha 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-5Ralpha 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.