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Dipeptidylpeptidase 4 negatively regulates colony-stimulating factor activity and stress hematopoiesis.

ABSTRACT: Enhancement of hematopoietic recovery after radiation, chemotherapy, or hematopoietic stem cell (HSC) transplantation is clinically relevant. Dipeptidylpeptidase (DPP4) cleaves a wide variety of substrates, including the chemokine stromal cell-derived factor-1 (SDF-1). In the course of experiments showing that inhibition of DPP4 enhances SDF-1-mediated progenitor cell survival, ex vivo cytokine expansion and replating frequency, we unexpectedly found that DPP4 has a more general role in regulating colony-stimulating factor (CSF) activity. DPP4 cleaved within the N-termini of the CSFs granulocyte-macrophage (GM)-CSF, G-CSF, interleukin-3 (IL-3) and erythropoietin and decreased their activity. Dpp4 knockout or DPP4 inhibition enhanced CSF activities both in vitro and in vivo. The reduced activity of DPP4-truncated versus full-length human GM-CSF was mechanistically linked to effects on receptor-binding affinity, induction of GM-CSF receptor oligomerization and signaling capacity. Hematopoiesis in mice after radiation or chemotherapy was enhanced in Dpp4(-/-) mice or mice receiving an orally active DPP4 inhibitor. DPP4 inhibition enhanced engraftment in mice without compromising HSC function, suggesting the potential clinical utility of this approach.

SUBMITTER: Broxmeyer HE

PROVIDER: S-EPMC3742313 | biostudies-literature | 2012 Dec

REPOSITORIES: biostudies-literature

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Dipeptidylpeptidase 4 negatively regulates colony-stimulating factor activity and stress hematopoiesis.

Broxmeyer Hal E HE Hoggatt Jonathan J O'Leary Heather A HA Mantel Charlie C Chitteti Brahmananda R BR Cooper Scott S Messina-Graham Steven S Hangoc Giao G Farag Sherif S Rohrabaugh Sara L SL Ou Xuan X Speth Jennifer J Pelus Louis M LM Srour Edward F EF Campbell Timothy B TB

Nature medicine 20121118 12

Enhancement of hematopoietic recovery after radiation, chemotherapy, or hematopoietic stem cell (HSC) transplantation is clinically relevant. Dipeptidylpeptidase (DPP4) cleaves a wide variety of substrates, including the chemokine stromal cell-derived factor-1 (SDF-1). In the course of experiments showing that inhibition of DPP4 enhances SDF-1-mediated progenitor cell survival, ex vivo cytokine expansion and replating frequency, we unexpectedly found that DPP4 has a more general role in regulati ...[more]

PMID: 23160239

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Project description:Currently, amino-terminal PEGylated human granulocyte colony stimulating factor (huG-CSF) is used to prevent and treat neutropenia. Although huG-CSF has been used as a drug for more than 20 years, it has three significant drawbacks: (i) it relies on PEG aldehyde for PEGylation of the alpha-amino group of the first amino acid, and this leads to non-specific PEGylation of the epsilon amino group of lysine residues within the G-CSF; (ii) longer-acting G-CSF variants are desirable to reduce the risk of chemotherapy-associated neutropenia; and (iii) G-CSF cannot be administered on the day of chemotherapy. In an attempt to overcome the above drawbacks, we engineered cysteine variants of G-CSF to facilitate the maleimide PEG-based site-specific PEGylation that leads to a highly homogenous PEGylated product. Importantly, we have demonstrated that 20 kDa thiol-reactive PEG conjugated by maleimide chemistry to the Cys2 G-CSF variant exhibits leukocyte proliferative activity similar to that of the commercially available G-CSF conjugated with aldehyde PEG in a neutropenia mice model. Moreover, we have demonstrated that PEGylation of the cysteine variant of huG-CSF with higher molecular weight PEGs, such as 30 kDa PEG and 40 kDa PEG, leads to significantly prolonged leukocyte proliferation activity compared to the variant conjugated with 20 kDa PEG. Importantly, even a half-dose of the engineered variant conjugated with 40 kDa PEG exhibited significantly longer biological activity than the commercially available 20 kDa PEGylated huG-CSF. Finally, we have demonstrated that administration of the engineered variant conjugated with 40 kDa PEG on the day of administration of cyclophosphamide for inducing neutropenia in mice can alleviate neutropenia through leukocyte proliferation. In summary, this study provides the design of site-specific PEGylated huG-CSF variants with improved therapeutic potential. It opens the possibility of long-acting and same-day prophylactic administration of G-CSF after chemotherapy drug regimens. These results may pave the way for the development of potential G-CSF derivatives possessing longer half-lives and favorable clinical attributes.

Project description:BackgroundStem cell factor (SCF) and granulocyte-colony stimulating factor (G-CSF) are well-characterized vital hematopoietic growth factors that regulate hematopoiesis. G-CSF and SCF synergistically exhibit a stimulatory effect on hematopoietic progenitors. The combination of G-CSF and SCF has been used for mobilization of peripheral blood progenitor cells in cancer and non-cancerous conditions. To overcome challenges connected with the administration of two cytokines, we developed two fusion proteins composed of human SCF and human G-CSF interspaced by an alpha-helix-forming peptide linker.MethodsThe recombinant proteins SCF-Lα-GCSF and GCSF-Lα-SCF were purified in three steps using an ion-exchange and mixed-mode chromatography. The purity and quantity of the proteins after each stage of purification was assessed using RP-HPLC, SDS-PAGE, and the Bradford assays. Purified proteins were identified using high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) and the Western blot analyses. The molecular weight was determined by size exclusion HPLC (SE-HPLC). The activity of heterodimers was assessed using cell proliferation assays in vitro. The capacity of recombinant fusion proteins to stimulate the increase of the absolute neutrophil count in rats was determined in vivo. The binding kinetics of the proteins to immobilized G-CSF and SCF receptors was measured using total internal reflection ellipsometry and evaluated by a standard Langmuir kinetics model.ResultsThe novel SCF-Lα-GCSF and GCSF-Lα-SCF proteins were synthesized in Escherichia coli. The purity of the heterodimers reached >90% as determined by RP-HPLC. The identity of the proteins was confirmed using the Western blot and HPLC/ESI-MS assays. An array of multimeric forms, non-covalently associated dimers or trimers were detected in the protein preparations by SE-HPLC. Each protein induced a dose-dependent proliferative response on the cell lines. At equimolar concentration, the heterodimers retain 70-140% of the SCF monomer activity (p ≤ 0.01) in promoting the M-07e cells proliferation. The G-CSF moiety in GCSF-Lα-SCF retained 15% (p ≤ 0.0001) and in SCF-Lα-GCSF retained 34% (p ≤ 0.01) of the monomeric G-CSF activity in stimulating the growth of G-NFS-60 cells. The obtained results were in good agreement with the binding data of each moiety in the fusion proteins to their respective receptors. The increase in the absolute neutrophil count in rats caused by the SCF-Lα-GCSF protein corresponded to the increase induced by a mixture of SCF and G-CSF.

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Dipeptidylpeptidase 4 negatively regulates colony-stimulating factor activity and stress hematopoiesis.

Publications

Dipeptidylpeptidase 4 negatively regulates colony-stimulating factor activity and stress hematopoiesis.

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