Effect of a structurally modified human granulocyte colony stimulating factor, G-CSFa, on leukopenia in mice and monkeys.

Abstract

BACKGROUND:

Granulocyte colony stimulating factor (G-CSF) regulates survival, proliferation, and differentiation of neutrophilic granulocyte precursors, Recombinant G-CSF has been used for the treatment of congenital and therapy-induced neutropenia and stem cell mobilization. Due to its intrinsic instability, recombinant G-CSF needs to be excessively and/or frequently administered to patients in order to maintain a plasma concentration high enough to achieve therapeutic effects. Therefore, there is a need for the development of G-CSF derivatives that are more stable and active in vivo.

METHODS:

Using site-direct mutagenesis and recombinant DNA technology, a structurally modified derivative of human G-CSF termed G-CSFa was obtained. G-CSFa contains alanine 17 (instead of cysteine 17 as in wild-type G-CSF) as well as four additional amino acids including methionine, arginine, glycine, and serine at the amino-terminus. Purified recombinant G-CSFa was tested for its in vitro activity using cell-based assays and in vivo activity using both murine and primate animal models.

RESULTS:

In vitro studies demonstrated that G-CSFa, expressed in and purified from E. coli, induced a much higher proliferation rate than that of wild-type G-CSF at the same concentrations. In vivo studies showed that G-CSFa significantly increased the number of peripheral blood leukocytes in cesium-137 irradiated mice or monkeys with neutropenia after administration of cyclophosphamide. In addition, G-CSFa increased neutrophil counts to a higher level in monkeys with a concomitant slower declining rate than that of G-CSF, indicating a longer half-life of G-CSFa. Bone marrow smear analysis also confirmed that G-CSFa was more potent than G-CSF in the induction of granulopoiesis in bone marrows of myelo-suppressed monkeys.

CONCLUSION:

G-CSFa, a structurally modified form of G-CSF, is more potent in stimulating proliferation and differentiation of myeloid cells of the granulocytic lineage than the wild-type counterpart both in vitro and in vivo. G-CSFa can be explored for the development of a new generation of recombinant therapeutic drug for leukopenia.

• Authors: Yongping Jiang, Wenhong Jiang, Yuchang Qiu, Wei Dai
• Journal: Journal of hematology & oncology (J Hematol Oncol) Vol. 4 Pg. 28 (Jun 13 2011) ISSN: 1756-8722 [Electronic] England
• PMID: 21668998 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Recombinant Proteins
• Granulocyte Colony-Stimulating Factor

Topics

• Animals
• Cell Differentiation (drug effects)
• Escherichia coli (genetics, metabolism)
• Granulocyte Colony-Stimulating Factor (blood, genetics, pharmacology)
• Haplorhini
• Hematopoietic Stem Cell Mobilization
• Humans
• Leukopenia (blood, drug therapy)
• Male
• Mice
• Mice, Inbred BALB C
• Mice, Inbred ICR
• Mutagenesis, Site-Directed
• Neutropenia (blood, drug therapy)
• Recombinant Proteins (blood, genetics, pharmacology)