Cathepsin K cleavage of angiopoietin-2 creates detrimental Tie2 antagonist fragments in sepsis
Takashi Suzuki, … , Sascha David, Samir M. Parikh
Takashi Suzuki, … , Sascha David, Samir M. Parikh
Published March 3, 2025
Citation Information: J Clin Invest. 2025;135(8):e174135. https://doi.org/10.1172/JCI174135.
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Research Article Inflammation Vascular biology

Cathepsin K cleavage of angiopoietin-2 creates detrimental Tie2 antagonist fragments in sepsis

Abstract

Elevated angiopoietin-2 is associated with diverse inflammatory conditions, including sepsis, a leading global cause of mortality. During inflammation, angiopoietin-2 antagonizes the endothelium-enriched receptor Tie2 to destabilize the vasculature. In other contexts, angiopoietin-2 stimulates Tie2. The basis for context-dependent antagonism remains incompletely understood. Here, we show that inflammation-induced proteolytic cleavage of angiopoietin-2 converts this ligand from Tie2 agonist to antagonist. Conditioned media from stimulated macrophages induced endothelial angiopoietin-2 secretion. Unexpectedly, this was associated with reduction of the 75 kDa full-length protein and appearance of new 25 and 50 kDa C-terminal fragments. Peptide sequencing proposed cathepsin K as a candidate protease. Cathepsin K was necessary and sufficient to cleave angiopoietin-2. Recombinant 25 and 50 kDa angiopoietin-2 fragments (cANGPT225 and cANGPT250) bound and antagonized Tie2. Cathepsin K inhibition with the phase 3 small-molecule inhibitor odanacatib improved survival in distinct murine sepsis models. Full-length angiopoietin-2 enhanced survival in endotoxemic mice administered odanacatib and, conversely, increased mortality in the drug’s absence. Odanacatib’s benefit was reversed by heterologous cANGPT225. Septic humans accumulated circulating angiopoietin-2 fragments, which were associated with adverse outcomes. These results identify cathepsin K as a candidate marker of sepsis and a proteolytic mechanism for the conversion of angiopoietin-2 from Tie2 agonist to antagonist, with therapeutic implications for inflammatory conditions associated with angiopoietin-2 induction.

Authors

Takashi Suzuki, Erik Loyde, Sara Chen, Valerie Etzrodt, Temitayo O. Idowu, Amanda J. Clark, Marie Christelle Saade, Brenda Mendoza Flores, Shulin Lu, Gabriel Birrane, Vamsidhara Vemireddy, Benjamin Seeliger, Sascha David, Samir M. Parikh

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Figure 5

Cathepsin K inhibition improves survival in distinct sepsis models and is dependent on ANGPT2 expression and conversion to cleaved products.

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Cathepsin K inhibition improves survival in distinct sepsis models and i...
(A and B) Survival curves for mice after (A) LPS administration (10 mg/kg) or (B) cecal ligation puncture (CLP). Vehicle or ODN (20 mg/kg) was injected i.p. 1 hour prior to LPS administration or CLP surgery. (C–F) Survival curves after hydrodynamic gene transfer of indicated plasmids (10 μg DNA in 10% saline based on body weight, 4 hours prior to vehicle or ODN). Vehicle or ODN (20 mg/kg, i.p.) was administered 1 hour prior to LPS (10 mg/kg) injection. LPS injection time was recorded as time 0. Empty vector (EV) + ODN was used as the control group. (G and H) Survival curves for Angpt2 heterozygous or littermate wild-type control mice after ODN and LPS injection performed, as per A. The Angpt2+/+ + Veh group was used as the control group. Numbers in parentheses indicate mice per group. *P < 0.05, **P < 0.01 by log-rank test.