AXL expression on homeostatic resident liver macrophages is reduced in cirrhosis following GAS6 production by hepatic stellate cells
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Published version
Author(s)
Type
Journal Article
Abstract
BACKGROUND & AIMS: AXL and MERTK expression on circulating monocytes modulated immune responses in patients with cirrhosis (CD14+HLA-DR+AXL+) and acute-on-chronic liver failure (CD14+MERTK+). AXL expression involved enhanced efferocytosis, sustained phagocytosis, but reduced TNF-α/IL-6 production and T cell activation, suggesting a homeostatic function. Axl was expressed on murine airway in tissues contacting the external environment- but not interstitial lung-, and tissue-resident synovial lining macrophages. We assessed AXL expression on tissue macrophages in patients with cirrhosis. METHODS: Using multiplexed immunofluorescence we compared AXL expression in liver biopsies in cirrhosis (n=22), chronic liver disease (n=8), non-cirrhotic portal hypertension (n=4) and healthy controls (n=4). Phenotype and function of isolated primary human liver macrophages were characterised by flow cytometry (cirrhosis, n=11; control, n=14) ex vivo. Also, AXL expression was assessed on peritoneal- (n=29) and gut macrophages (n=16) from cirrhotic patients. Regulation of AXL expression was analysed in vitro and ex vivo using primary hepatic stellate cells (HSCs), LX-2 cells and GAS6 in co-culture experiments. RESULTS: AXL was expressed on resident (CD68+) but not tissue-infiltrating (MAC387+) liver macrophages, hepatocytes, HSCs, or sinusoidal endothelial cells. Prevalence of hepatic CD68+AXL+ cells significantly decreased with cirrhosis progression: (Healthy 90.2%; Child Pugh A 76.1%; B 64.5%; C 18.7%, all p<0.05) and negatively correlated with MELD and CRP (all p<0.05). AXL-expressing hepatic macrophages were CD68highHLA-DRhighCD16highCD206high. AXL expression also decreased on gut and peritoneal macrophages from cirrhotic patients, but increased in regional lymph nodes. GAS6, enriched in the cirrhotic liver, appeared to be secreted by HSCs and down-regulate AXL in vitro. CONCLUSIONS: Decreased AXL expression on resident liver macrophages in advanced cirrhosis, potentially in response to activated HSCs-secreted GAS6, suggests a role for AXL in the regulation of hepatic immune homeostasis.
Date Issued
2023
Date Acceptance
2023-03-27
Citation
Cellular and Molecular Gastroenterology and Hepatology, 2023, 16 (1), pp.17-37
ISSN
2352-345X
Publisher
Elsevier
Start Page
17
End Page
37
Journal / Book Title
Cellular and Molecular Gastroenterology and Hepatology
Volume
16
Issue
1
Copyright Statement
© 2023 The Authors. Published by Elsevier Inc. on behalf of the AGA
Institute. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/).
Institute. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/37004869
PII: S2352-345X(23)00047-4
Subjects
cirrhosis
innate immunity
resident liver macrophages
TAM receptors
Publication Status
Published
Coverage Spatial
United States
Date Publish Online
2023-03-31