Description:
Novel C3aR
agonists and antagonists for inhibiting pro-inflammatory activities of the human
complement system targeting C3aR
Princeton Docket # 12-2813
Novel agonists to C3aR have been designed using a de novo design
framework. The best predicted peptides were experimentally validated using a rat
basophilic leukemia cell degranulation assay and a monocytic cell calcium flux
assay.
Of the peptides tested using a degranulation assay in
C3aR-transfected rat basophilic leukemia cells, two were prominent agonists
(EC50 values in the nanomolar range) and two others were partial agonists (IC50
values in the nanomolar range). Further testing of these lead compounds in a
calcium flux assay in U937 cells yielded similar results, although with reduced
potencies compared to transfected cells. The partial agonists also displayed
full antagonist activity when tested in a C3aR inhibition assay. In addition,
the electrostatic potential profile was shown to potentially discriminate
between full agonists and partial agonists.
The peptides will be tested in human primary cells (human
neutrophils), and mouse cells (peritoneal macrophages) before testing in
inflammation animal models as published findings confirm C3aR as a putative
therapeutic target for inflammation.
Publication:
Bellows-Peterson, ML, Fung HK, Floudas CA, et al. ¿De Novo Design
with C3a Receptor Agonist and Antagonist Activities: Theoretical Predictions and
Experimental Validation, Journal of Medicinal Chemistry, 2012, 55(9) 4159-4168.
Background
A de novo design framework with a ranking metric based on fold
specificities was applied to the design of C3a receptor (C3aR) agonists and
antagonists. The design is based upon the structure of C3a, which activates
C3aR. C3a is a 77-residue peptide that mediates the pro-inflammatory activities
in the human complement system and possibly has opposing immunological roles in
some cellular systems. Improper activation of the complement system can cause
tissue injury in various pathological conditions and contributes to several
immune diseases, including stroke, heart attack, reperfusion injuries, and
rheumatoid arthritis. The crystal structure of C3a, as well as flexible template
structures generated by MD simulations with explicit solvation via water
molecules, was employed as the design template.
The framework utilizes two stages: a sequences selection stage and
a binding affinity calculation stage. The sequence selection stage produces a
rank-ordered list of amino acid sequences with the lowest energies based upon
the template structure. The second stage re-ranks the sequences from stage one
using either a fold specificity or an approximate binding affinity. Since
structural information of the C3a:C3aR complex was unknown, only fold
specificity calculations could be employed. Fold specificity measures how likely
a given sequence will fold into the design template structure. Thus the design
was driven by the hypothesis that structure implies function, and novel
sequences of C3a that adopt the C3a fold are potential candidates for C3aR
agonists or antagonists.
Intellectual property and technology status:
Patent pending.
Princeton is seeking to identify appropriate partners for the
further development and commercialization of this
technology.
Contact:
Laurie
Tzodikov
Princeton University Office of Technology Licensing
(609)
258-7256 tzodikov@princeton.edu
Wenting
Luo
Princeton
University Office of Technology Licensing
(609)
258-5579 wluo@princeton.edu