Neutrophil CEACAM1 determines susceptibility to NETosis by regulating the S1PR2/S1PR3 axis in liver transplantation
Hirofumi Hirao, … , Fady M. Kaldas, Jerzy W. Kupiec-Weglinski
Hirofumi Hirao, … , Fady M. Kaldas, Jerzy W. Kupiec-Weglinski
Published February 1, 2023
Citation Information: J Clin Invest. 2023;133(3):e162940. https://doi.org/10.1172/JCI162940.
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Research Article

Neutrophil CEACAM1 determines susceptibility to NETosis by regulating the S1PR2/S1PR3 axis in liver transplantation

Abstract

Neutrophils, the largest innate immune cell population in humans, are the primary proinflammatory sentinel in the ischemia-reperfusion injury (IRI) mechanism in orthotopic liver transplantation (OLT). Carcinoembryonic antigen–related cell adhesion molecule 1 (CEACAM1, CC1, or CD66a) is essential in neutrophil activation and serves as a checkpoint regulator of innate immune-driven IRI cascade in OLT. Although CC1 alternative splicing generates two functionally distinct short and long cytoplasmic isoforms, their role in neutrophil activation remains unknown. Here, we undertook molecular and functional studies to interrogate the significance of neutrophil CC1 signaling in mouse and human OLT recipients. In the experimental arm, we employed a mouse OLT model to document that ablation of recipient-derived neutrophil CC1-long (CC1-L) isotype aggravated hepatic IRI by promoting neutrophil extracellular traps (NETs). Notably, by regulating the S1P–S1PR2/S1PR3 axis, neutrophil CC1-L determined susceptibility to NET formation via autophagy signaling. In the clinical arm, liver grafts from 55 transplant patients selectively enriched for neutrophil CC1-L showed relative resistance to ischemia-reperfusion (IR) stress/tissue damage, improved hepatocellular function, and clinical outcomes. In conclusion, despite neutrophils being considered a principal villain in peritransplant tissue injury, their CC1-L isoform may serve as a regulator of IR stress resistance/NETosis in human and mouse OLT recipients.

Authors

Hirofumi Hirao, Hidenobu Kojima, Kenneth J. Dery, Kojiro Nakamura, Kentaro Kadono, Yuan Zhai, Douglas G. Farmer, Fady M. Kaldas, Jerzy W. Kupiec-Weglinski

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Figure 10

CC1-L level and CC1-L/CathG ratio are associated with hepatocellular function and innate/adaptive immune responses in OLT patients.

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CC1-L level and CC1-L/CathG ratio are associated with hepatocellular fun...
(A) Human OLT Bx (n = 55), collected 2 hours after reperfusion, were analyzed for CC1-L by WB with β-actin normalization and for CathG by qRT-PCR with normalization to GAPDH. (B) Four representative WB of CC1-L expression are shown. Case a, low–CC1-L; cases b/c, intermediate CC1-L; case d, high–CC1-L. (C) Relationship between CC1-L and CathG. (D) Relationship between CC1L/CathG and sAST/sALT at POD1. r, Spearman’s correlation coefficient. (E) Human OLT Bx samples (2 hours after reperfusion) were classified into low (n = 28) and high (n = 27) CC1-L/CathG groups. (F) sAST and sALT levels at POD1–7. *P < 0.05, Mann-Whitney U test. Data are represented as mean ± SEM. (G) Incidence of EAD. Fisher’s exact test. (H) qRT-PCR–assisted detection of mRNA coding for CD4, CD8, CD28, IL17, CD68, CD80, CD86, TLR4, and CXCL-10. Data normalized to GAPDH gene expression are shown in dot plots, and bars indicate mean ± SEM. *P < 0.05; **P < 0.01, Mann-Whitney U test.