Recombinant G-CSF-ApoAI Fusion Protein Is a Pleiotropic Factor

Area of Science:

• Biochemistry
• Immunology
• Biotechnology

Background:

• Granulocyte colony-stimulating factor (G-CSF) is crucial for neutrophil development.
• Apolipoprotein A-I (ApoAI) plays a role in lipid metabolism and possesses anti-inflammatory properties.
• Developing novel therapeutic proteins with enhanced functionalities is an active area of research.

Purpose of the Study:

• To develop and characterize a recombinant chimeric protein fusing human G-CSF with apolipoprotein A-I (G-CSF-ApoAI).
• To evaluate the biological activities of G-CSF-ApoAI on myeloid cell differentiation and function.
• To assess the potential of G-CSF-ApoAI in modulating inflammation and enhancing pathogen clearance.

Main Methods:

• Recombinant expression of G-CSF-ApoAI in *Pichia pastoris*.
• Assays using human bone marrow cells to assess granulocyte activity (differentiation, maturation, progenitor cell viability).
• Assays using human mononuclear cells and THP cells to assess monocytic activity (cell count, CD14+ expression).
• Caspase 3/7 expression analysis to evaluate apoptosis.
• In vitro models of LPS-induced inflammation to assess cytokine regulation and phagocytosis.

Main Results:

• The G-CSF-ApoAI fusion protein retained G-CSF's granulocyte activity, promoting neutrophil differentiation and progenitor cell viability.
• G-CSF-ApoAI exhibited monocytic activity, increasing total and CD14+ cell counts.
• The chimeric protein reduced caspase 3/7 expression, indicating maintained cell viability.
• G-CSF-ApoAI accelerated cytokine regulation and increased phagocytosis by 1.4-fold compared to G-CSF in an LPS-induced inflammation model.

Conclusions:

• The recombinant G-CSF-ApoAI is a functional chimeric protein with both granulocytic and monocytic activities.
• G-CSF-ApoAI demonstrates enhanced immunomodulatory effects, including accelerated inflammation resolution and improved phagocytosis.
• This novel pleiotropic factor holds promise for applications in pathogen clearance, particularly in infected wounds.