TY - JOUR
T1 - Crystal Structure of Cleaved Serp-1, a Myxomavirus-Derived Immune Modulating Serpin
T2 - Structural Design of Serpin Reactive Center Loop Peptides with Improved Therapeutic Function
AU - Mahon, Brian P.
AU - Ambadapadi, Sriram
AU - Yaron, Jordan R.
AU - Lomelino, Carrie L.
AU - Pinard, Melissa A.
AU - Keinan, Shahar
AU - Kurnikov, Igor
AU - Macaulay, Colin
AU - Zhang, Liqiang
AU - Reeves, Westley
AU - McFadden, Douglas
AU - Tibbetts, Scott
AU - McKenna, Robert
AU - Lucas, Alexandra R.
N1 - Funding Information:
*Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892. E-mail: brian. mahon@nih.gov. Telephone: (301) 402-6670. *Biodesign Institute, Arizona State University, Tempe, AZ 85287. E-mail: alexluc1@asu.edu. Telephone: (480) 965-2392. ORCID Shahar Keinan: 0000-0001-8703-901X Alexandra R. Lucas: 0000-0003-3869-5373 Author Contributions B.P.M. performed and analyzed experiments and wrote the manuscript. S.A., J.R.Y., C.L.L., M.A.P., S.K., I.K., S.T., L.Z., W.R., and C.M. performed and analyzed experiments and contributed to the production of samples. G.M., R.M., and A.R.L. designed the study and contributed to writing and editing the manuscript. All authors reviewed results and approved the final version of the manuscript. Funding This work was supported by National Institutes of Health Grants 1RC1HL100202-01, GM109524, and 1R01 AI100987-01A1 and American Heart Association Grants 0855421 E and 17GRNT33460327. Notes The authors declare no competing financial interest.
PY - 2018/2/20
Y1 - 2018/2/20
N2 - The Myxomavirus-derived protein Serp-1 has potent anti-inflammatory activity in models of vasculitis, lupus, viral sepsis, and transplant. Serp-1 has also been tested successfully in a Phase IIa clinical trial in unstable angina, representing a "first-in-class" therapeutic. Recently, peptides derived from the reactive center loop (RCL) have been developed as stand-alone therapeutics for reducing vasculitis and improving survival in MHV68-infected mice. However, both Serp-1 and the RCL peptides lose activity in MHV68-infected mice after antibiotic suppression of intestinal microbiota. Here, we utilize a structure-guided approach to design and test a series of next-generation RCL peptides with improved therapeutic potential that is not reduced when the peptides are combined with antibiotic treatments. The crystal structure of cleaved Serp-1 was determined to 2.5 Å resolution and reveals a classical serpin structure with potential for serpin-derived RCL peptides to bind and inhibit mammalian serpins, plasminogen activator inhibitor 1 (PAI-1), anti-thrombin III (ATIII), and α-1 antitrypsin (A1AT), and target proteases. Using in silico modeling of the Serp-1 RCL peptide, S-7, we designed several modified RCL peptides that were predicted to have stronger interactions with human serpins because of the larger number of stabilizing hydrogen bonds. Two of these peptides (MPS7-8 and -9) displayed extended activity, improving survival where activity was previously lost in antibiotic-treated MHV68-infected mice (P < 0.0001). Mass spectrometry and kinetic assays suggest interaction of the peptides with ATIII, A1AT, and target proteases in mouse and human plasma. In summary, we present the next step toward the development of a promising new class of anti-inflammatory serpin-based therapeutics.
AB - The Myxomavirus-derived protein Serp-1 has potent anti-inflammatory activity in models of vasculitis, lupus, viral sepsis, and transplant. Serp-1 has also been tested successfully in a Phase IIa clinical trial in unstable angina, representing a "first-in-class" therapeutic. Recently, peptides derived from the reactive center loop (RCL) have been developed as stand-alone therapeutics for reducing vasculitis and improving survival in MHV68-infected mice. However, both Serp-1 and the RCL peptides lose activity in MHV68-infected mice after antibiotic suppression of intestinal microbiota. Here, we utilize a structure-guided approach to design and test a series of next-generation RCL peptides with improved therapeutic potential that is not reduced when the peptides are combined with antibiotic treatments. The crystal structure of cleaved Serp-1 was determined to 2.5 Å resolution and reveals a classical serpin structure with potential for serpin-derived RCL peptides to bind and inhibit mammalian serpins, plasminogen activator inhibitor 1 (PAI-1), anti-thrombin III (ATIII), and α-1 antitrypsin (A1AT), and target proteases. Using in silico modeling of the Serp-1 RCL peptide, S-7, we designed several modified RCL peptides that were predicted to have stronger interactions with human serpins because of the larger number of stabilizing hydrogen bonds. Two of these peptides (MPS7-8 and -9) displayed extended activity, improving survival where activity was previously lost in antibiotic-treated MHV68-infected mice (P < 0.0001). Mass spectrometry and kinetic assays suggest interaction of the peptides with ATIII, A1AT, and target proteases in mouse and human plasma. In summary, we present the next step toward the development of a promising new class of anti-inflammatory serpin-based therapeutics.
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U2 - 10.1021/acs.biochem.7b01171
DO - 10.1021/acs.biochem.7b01171
M3 - Article
C2 - 29227673
AN - SCOPUS:85039057095
VL - 57
SP - 1096
EP - 1107
JO - Biochemistry
JF - Biochemistry
SN - 0006-2960
IS - 7
ER -