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A NANOBODY molecule that blocks MerTK ectodomain cleavage in vitro and in vivo
Linde Duprez1, Ayse Kilic2, Hélène Bruwiere1
1Large Molecule Research, NANOBODY Research Platform, Sanofi, Ghent, Belgium.
Abstract:
The membrane receptor MerTK is critical for the resolution of inflammation and thus is of pharmacological interest. MerTK function is inhibited by the proteolytic cleavage of its extracellular domain leading to the formation of soluble Mer (sMer). We describe here the NANOBODY molecule A0445046C08 and its half-life-extended version A044500050. Both bound selectively to MerTK and blocked lipopolysaccharide-induced MerTK cleavage in primary macrophages without influencing ligand binding or kinase activity of MerTK. A044500050 reduced Zymosan-induced sMer levels in the peritoneal lavage fluid of a mouse model with sterile peritonitis. The study demonstrates that NANOBODY molecules can be generated that selectively inhibit ectodomain shedding and outlines a novel pharmacological approach for targeting membrane proteins where aberrant cleavage plays a pathogenic role.
Insights
Researchers developed NANOBODY molecules that block MerTK cleavage, a key step in inflammation resolution. This offers a new therapeutic strategy for targeting membrane proteins involved in disease.
Area of Science:
- Immunology
- Pharmacology
- Molecular Biology
Background:
- The membrane receptor MerTK plays a crucial role in resolving inflammation.
- MerTK activity is regulated by proteolytic cleavage, releasing soluble Mer (sMer) and inhibiting its function.
- Aberrant MerTK cleavage is implicated in inflammatory diseases, making it a therapeutic target.
Purpose of the Study:
- To develop NANOBODY molecules that selectively inhibit MerTK ectodomain shedding.
- To evaluate the efficacy of these NANOBODY molecules in blocking MerTK cleavage and reducing sMer levels in vitro and in vivo.
Main Methods:
- Generation and characterization of NANOBODY molecules (A0445046C08 and A044500050) targeting MerTK.
- Assessment of NANOBODY binding selectivity and impact on MerTK ligand binding and kinase activity.
- Inhibition of lipopolysaccharide-induced MerTK cleavage in primary macrophages.
- Evaluation of NANOBODY A044500050 in a mouse model of sterile peritonitis to measure Zymosan-induced sMer levels.
Main Results:
- NANOBODY molecules A0445046C08 and A044500050 selectively bound to MerTK.
- Both NANOBODIES effectively blocked lipopolysaccharide-induced MerTK cleavage in primary macrophages without affecting MerTK's ligand binding or kinase activity.
- NANOBODY A044500050 significantly reduced Zymosan-induced sMer levels in vivo in a mouse model of sterile peritonitis.
Conclusions:
- NANOBODY technology can be utilized to generate inhibitors of membrane protein ectodomain shedding.
- Selective inhibition of MerTK cleavage represents a novel pharmacological strategy for treating inflammatory conditions.
- Targeting aberrant cleavage of membrane proteins offers a promising therapeutic avenue for various diseases.
