Circulating PEG-indoleamine 2,3-dioxygenase ameliorates diverse inflammatory diseases without toxicity or compromising immunocompetence

J Jennifer A. Simonovich (J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida) R Ryan A. Clark (J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida) A Alexander J. Kwiatkowski (J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida) M Madeline J. Fuchs (J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida) M Mariana E. Viso (J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida) C Chen Lu S Sabrina L. Macias (J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida) I Isabella Pinto (J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida) A Abhishek P. Shrestha (Department of Surgery, Division of Transplantation and Hepatobiliary Surgery, College of Medicine, University of Florida) T Tran B. Ngo (J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida) S Sergio Duarte (Department of Surgery, Division of Transplantation and Hepatobiliary Surgery, College of Medicine, University of Florida) Y Yong He (Department of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University) Q Qiongyao Hu (Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida) G Guanyi Lu (Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida) J Joseph B. Hartman (Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida) G Gang Su S Salvatore T. Scali (Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida) S Scott A. Berceli (Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida) A Ashish K. Sharma (Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida) G Gilbert R. Upchurch (Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida) S Shamima Islam (Department of Immunology, H. Lee Moffitt Cancer Center and Research Institute) A Arun Wanchoo (J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida) G Gregory A. Hudalla (J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida) S Scott T. Robinson (Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida) A Ali Zarrinpar (Department of Surgery, Division of Transplantation and Hepatobiliary Surgery, College of Medicine, University of Florida) D Dorina Avram (Department of Immunology, H. Lee Moffitt Cancer Center and Research Institute) B Benjamin G. Keselowsky (J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida)

Abstract

Indoleamine 2,3-dioxygenase (IDO), the enzyme responsible for tryptophan catabolism, is protective in many autoimmune and inflammatory diseases. We previously developed a localized immunomodulation approach through the fusion of IDO to a carbohydrate binding protein [E. Bracho-Sanchez et al. , Nat. Biomed. Eng. 7 , 1156–1169 (2023)]. Here we further develop IDO as a protein therapeutic for inflammation, investigating systemic delivery via conjugation of poly(ethylene glycol) (PEG) to IDO. PEGylation extended circulation time and treatment PEG-IDO demonstrated therapeutic efficacy in five autoimmune and inflammatory models. Treatment with a single dose of PEG-IDO resulted in reversal of hind limb paralysis in experimental autoimmune encephalomyelitis as model of multiple sclerosis; protected against hepatic damage in liver ischemia-reperfusion injury; prevention of abdominal aortic aneurysm; and decreased severity of imiquimod-induced psoriasis. Treatment with two doses of PEG-IDO provided maintenance of body weight and colon length in acute ulcerative colitis. PEG-IDO treatment increased regulatory T cell populations and reduced pathogenic Th17 cell populations and inflammatory cytokine production. Systemic delivery of PEG-IDO had little-to-no off-target effects. Mice maintained immunocompetency, clearing the Listeria monocytogenes infection, and had no observed toxicity. Additionally, PEG-IDO increased serum kynurenine, consistent with a kynurenine-mediated mechanism of action. These findings demonstrate systemic immunomodulation via circulating PEG-IDO ameliorates a breadth of disparate autoinflammatory diseases, protecting against inflammation-driven tissue destruction in spinal cord, liver, abdominal aorta, skin, and colon, while presenting a positive safety profile, and expanding the scope of potential applications for this therapeutic approach.

Article Details

Volume / Issue Vol. 123, Issue 28
Published July 14, 2026
ISSN 0027-8424
Publisher National Academy of Sciences

Authors (27)

J

Jennifer A. Simonovich

J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida

R

Ryan A. Clark

J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida

A

Alexander J. Kwiatkowski

J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida

M

Madeline J. Fuchs

J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida

M

Mariana E. Viso

J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida

C

Chen Lu

S

Sabrina L. Macias

J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida

I

Isabella Pinto

J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida

A

Abhishek P. Shrestha

Department of Surgery, Division of Transplantation and Hepatobiliary Surgery, College of Medicine, University of Florida

T

Tran B. Ngo

J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida

S

Sergio Duarte

Department of Surgery, Division of Transplantation and Hepatobiliary Surgery, College of Medicine, University of Florida

Y

Yong He

Department of Pathogen Biology, School of Basic Medical Sciences, Anhui Medical University

Q

Qiongyao Hu

Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida

G

Guanyi Lu

Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida

J

Joseph B. Hartman

Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida

G

Gang Su

S

Salvatore T. Scali

Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida

S

Scott A. Berceli

Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida

A

Ashish K. Sharma

Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida

G

Gilbert R. Upchurch

Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida

S

Shamima Islam

Department of Immunology, H. Lee Moffitt Cancer Center and Research Institute

A

Arun Wanchoo

J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida

G

Gregory A. Hudalla

J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida

S

Scott T. Robinson

Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, College of Medicine, University of Florida

A

Ali Zarrinpar

Department of Surgery, Division of Transplantation and Hepatobiliary Surgery, College of Medicine, University of Florida

D

Dorina Avram

Department of Immunology, H. Lee Moffitt Cancer Center and Research Institute

B

Benjamin G. Keselowsky

J. Crayton Pruitt Family Department of Biomedical Engineering, Herbert Wertheim College of Engineering, University of Florida