OC 56.1 - Thiol Isomerase ERp72 Cleaves Allosteric Disulfide Bond on CD11b to Regulate Integrin Mac-1 Activity and Neutrophil Recruitment

Tuesday, June 25, 2024

09:30 – 09:45 ICT

Room: 111 A-C

Co-Author(s)

YL

Yaofeng Li

PhD Student
Department of Pharmacology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology
Wuhan, Hubei, China (People's Republic)
XX

Xulin Xu

Associate Professor
Department of Pharmacology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology
Wuhan, Hubei, China (People's Republic)
HW

Haoqing J. Wang

PhD student
School of Biomedical Engineering, Faculty of Engineering, The University of Sydney
Darlington, New South Wales, Australia
YC

Yiyao Chen

PhD Student
School of Biomedical Engineering, Faculty of Engineering, The University of Sydney
Darlington, New South Wales, Australia
YC

Yaobing Chen

Associate Professor
Institute of Pathology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology
Wuhan, Hubei, China (People's Republic)
JC

Joyce Chiu

Lecturer
The Centenary Institute, University of Sydney
Sydney, New South Wales, Australia
LL

Li Li

PhD Student
Department of Pharmacology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology
Wuhan, Hubei, China (People's Republic)
LW

Lei Wang

PhD Student
Department of Pharmacology, School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and Technology
Wuhan, Hubei, China (People's Republic)
JW

Jinyu Wang

Lecturer
School of Stomatology, Tongji Medical Collage, Huazhong University of Science and Technology, and the Key Laboratory of Oral and Maxillofacial Development and Regeneration of Hubei Province
Wuhan, Hubei, China (People's Republic)
Zhaoming Tang, MD

Director of the Clinical Hemostasis and Thrombosis Laboratory
Department of Clinical Laboratory, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology
Wuhan, Hubei, China (People's Republic)
LR

Lehao Ren

Lecturer
Department of Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology
Wuhan, Hubei, China (People's Republic)
HL

Hongliang Li

Professor
Laboratory of Chinese Herbal Pharmacology, Department of Pharmacy, Renmin Hospital; Biomedical Research Institute, School of Pharmaceutical Sciences and Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine
Shiyan, Hubei, China (People's Republic)
XW

Xuanbin Wang

Professor
Laboratory of Chinese Herbal Pharmacology, Department of Pharmacy, Renmin Hospital; Biomedical Research Institute, School of Pharmaceutical Sciences and Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Hubei University of Medicine
Shiyan, Hubei, China (People's Republic)
SJ

Si Jin

Professor
Department of Endocrinology, Institute of Geriatric Medicine, Liyuan Hospital, Tongji Medical College, Huazhong University of Science and Technology
Wuhan, Hubei, China (People's Republic)
YW

Yi Wu, MD, PhD

Professor
Soochow University
Suzhou, Jiangsu, China (People's Republic)
MH

Mingdong Huang

Professor
College of Chemistry, Fuzhou University
Fuzhou, Fujian, China (People's Republic)
Lining A. Ju, PhD

University of Sydney, Australia

Presenting Author(s)

Chao Fang, PhD

Professor of Pharmacology
Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology
Wuhan, Hubei, China (People's Republic)

Background: Integrins mediate the adhesion, crawling and migration of neutrophils during vascular inflammation. Thiol exchange is important in the regulation of integrin functions. ER-resident protein 72 (ERp72) is a member of the thiol isomerase family responsible for the catalysis of disulfide rearrangement.

Aims: This study aims to determine the role of ERp72 in the regulation of integrin αMβ2 (Mac-1) on neutrophils.

Methods: Intravital microscopy of the cremaster microcirculation was performed to determine in vivo neutrophil movement. Static adhesion, flow chamber and flowcytometry were used to evaluate in vitro integrin functions. Confocal fluorescent microscopy and co-immunoprecipitation were utilized to characterize the interactions between ERp72 and Mac-1 on neutrophil surface. Cell-impermeable probes and mass spectrometry were used to label reactive thiols and identify target disulfide bonds. Biomembrane Force Probe (BFP) was performed to quantitatively measure the binding affinity of Mac-1. A murine model of acute lung injury (ALI) induced by LPS was utilized to evaluate neutrophil-associated vasculopathy.

Results: ERp72-deficient neutrophils exhibited increased rolling but decreased adhesion/crawling on inflamed venules in vivo, and defective static adhesion in vitro. The defect was due to defective activation of integrin Mac-1 but not Lymphocyte function-associated antigen-1 (LFA-1) using blocking or epitope-specific antibodies. ERp72 interacted with Mac-1 in lipid rafts on neutrophil surface leading to the reduction of C654-C711 disulfide bond in αM subunit that is critical for Mac-1 activation. Recombinant ERp72, via its catalytic motifs, increased the binding affinity of Mac-1 with Intercellular adhesion molecule-1 (ICAM-1) and rescued the defective adhesion of ERp72-deficient neutrophils both in vitro and in vivo. Deletion of ERp72 in the bone marrow inhibited neutrophil infiltration, ameliorated tissue damage, and increased survival during murine ALI.

Conclusion(s): Extracellular ERp72 regulates integrin Mac-1 activity by catalyzing disulfide rearrangement on αM subunit and may be a novel target for the treatment of neutrophil-associated vasculopathy.