Oral N-acetylcysteine decreases IFN-γ production and ameliorates ischemia-reperfusion injury in steatotic livers.

Abstract

Type 1 Natural Killer T-cells (NKT1 cells) play a critical role in mediating hepatic ischemia-reperfusion injury (IRI). Although hepatic steatosis is a major risk factor for preservation type injury, how NKT cells impact this is understudied. Given NKT1 cell activation by phospholipid ligands recognized presented by CD1d, we hypothesized that NKT1 cells are key modulators of hepatic IRI because of the increased frequency of activating ligands in the setting of hepatic steatosis. We first demonstrate that IRI is exacerbated by a high-fat diet (HFD) in experimental murine models of warm partial ischemia. This is evident in the evaluation of ALT levels and Phasor-Fluorescence Lifetime (Phasor-FLIM) Imaging for glycolytic stress. Polychromatic flow cytometry identified pronounced increases in CD45+CD3+NK1.1+NKT1 cells in HFD fed mice when compared to mice fed a normal diet (ND). This observation is further extended to IRI, measuring ex vivo cytokine expression in the HFD and ND. Much higher interferon-gamma (IFN-γ) expression is noted in the HFD mice after IRI. We further tested our hypothesis by performing a lipidomic analysis of hepatic tissue and compared this to Phasor-FLIM imaging using "long lifetime species", a byproduct of lipid oxidation. There are higher levels of triacylglycerols and phospholipids in HFD mice. Since N-acetylcysteine (NAC) is able to limit hepatic steatosis, we tested how oral NAC supplementation in HFD mice impacted IRI. Interestingly, oral NAC supplementation in HFD mice results in improved hepatic enhancement using contrast-enhanced magnetic resonance imaging (MRI) compared to HFD control mice and normalization of glycolysis demonstrated by Phasor-FLIM imaging. This correlated with improved biochemical serum levels and a decrease in IFN-γ expression at a tissue level and from CD45+CD3+CD1d+ cells. Lipidomic evaluation of tissue in the HFD+NAC mice demonstrated a drastic decrease in triacylglycerol, suggesting downregulation of the PPAR-γ pathway.

• Authors: Jedson R Liggett, Jiman Kang, Suman Ranjit, Olga Rodriguez, Katrina Loh, Digvijay Patil, Yuki Cui, Anju Duttargi, Sang Nguyen, Britney He, Yichien Lee, Kesha Oza, Brett S Frank, DongHyang Kwon, Heng-Hong Li, Bhaskar Kallakury, Andrew Libby, Moshe Levi, Simon C Robson, Thomas M Fishbein, Wanxing Cui, Chris Albanese, Khalid Khan, Alexander Kroemer
• Journal: Frontiers in immunology (Front Immunol) Vol. 13 Pg. 898799 ( 2022) ISSN: 1664-3224 [Electronic] Switzerland
• PMID: 36148239 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2022 Liggett, Kang, Ranjit, Rodriguez, Loh, Patil, Cui, Duttargi, Nguyen, He, Lee, Oza, Frank, Kwon, Li, Kallakury, Libby, Levi, Robson, Fishbein, Cui, Albanese, Khan and Kroemer.

Chemical References

• Cytokines
• Ligands
• Peroxisome Proliferator-Activated Receptors
• Phospholipids
• Triglycerides
• Interferon-gamma
• Acetylcysteine

Topics

• Acetylcysteine (pharmacology)
• Animals
• Cytokines
• Fatty Liver (drug therapy)
• Interferon-gamma
• Ligands
• Mice
• Mice, Inbred C57BL
• Peroxisome Proliferator-Activated Receptors
• Phospholipids
• Reperfusion Injury (etiology)
• Triglycerides