Insulin-like growth factor-1 fused with thrombopoietin mimetic peptide effectively increase platelets count in vivo.

OBJECTIVES To design the expression of fusion proteins containing one or 2 thrombopoietin mimetic peptide (TMP). METHODS This study was conducted at Harbin Pharmaceutical Group Research and Development Center, Harbin, China from June 2009 to January 2010. We designed the protein that was fused to the C-terminus of insulin-like growth factors (IGF-1) by a flexible peptide linker by Dami cell proliferation assay, colony-forming assay, and analysis of platelet in mice to prove our hypothesis. The total number of mice used was 48 in all 4 groups. RESULTS The fusion proteins were produced in Escherichia coli BL21 (DE3) at up to 26% of the total cell proteins. Subsequent biological activity assays showed that the fusion proteins exhibited higher potency than recombinant human thrombopoietin (TPO). Our results showed that the fusion proteins IGF-1-TMP exhibited higher biological activities than TMP in Dami cell proliferation, human cord blood cell colony-forming assays, and in experiments on acute myeloid radiation sickness mice, which can effectively increase the number of platelets. CONCLUSIONS Experiments in mice and biology activity assay, which can effectively increase the number of platelets, indicated that it has a potential role in pharmaceutical applications for the treatment of thrombocytopenia.