TREM2 Regulates the Removal of Apoptotic Cells and Inflammatory Processes during the Progression of NAFLD

TY - JOUR

T1 - TREM2 Regulates the Removal of Apoptotic Cells and Inflammatory Processes during the Progression of NAFLD

AU - Liebold, Imke

AU - Meyer, Simon

AU - Heine, Markus

AU - Kuhl, Anastasia

AU - Witt, Jennifer

AU - Eissing, Leah

AU - Fischer, Alexander W

AU - Koop, Anja Christina

AU - Kluwe, Johannes

AU - Wiesch, Julian Schulze Zur

AU - Wehmeyer, Malte

AU - Knippschild, Uwe

AU - Scheja, Ludger

AU - Heeren, Joerg

AU - Bosurgi, Lidia

AU - Worthmann, Anna

PY - 2023/1/17

Y1 - 2023/1/17

N2 - Nonalcoholic fatty liver disease (NAFLD) is the most common liver pathology worldwide. In mice and humans, NAFLD progression is characterized by the appearance of TREM2-expressing macrophages in the liver. However, their mechanistic contributions to disease progression have not been completely elucidated. Here, we show that TREM2+ macrophages prevent the generation of a pro-inflammatory response elicited by LPS-laden lipoproteins in vitro. Further, Trem2 expression regulates bone-marrow-derived macrophages (BMDMs) and Kupffer cell capacity to phagocyte apoptotic cells in vitro, which is dependent on CD14 activation. In line with this, loss of Trem2 resulted in an increased pro-inflammatory response, which ultimately aggravated liver fibrosis in murine models of NAFLD. Similarly, in a human NAFLD cohort, plasma levels of TREM2 were increased and hepatic TREM2 expression was correlated with higher levels of liver triglycerides and the acquisition of a fibrotic gene signature. Altogether, our results suggest that TREM2+ macrophages have a protective function during the progression of NAFLD, as they are involved in the processing of pro-inflammatory lipoproteins and phagocytosis of apoptotic cells and, thereby, are critical contributors for the re-establishment of liver homeostasis.

AB - Nonalcoholic fatty liver disease (NAFLD) is the most common liver pathology worldwide. In mice and humans, NAFLD progression is characterized by the appearance of TREM2-expressing macrophages in the liver. However, their mechanistic contributions to disease progression have not been completely elucidated. Here, we show that TREM2+ macrophages prevent the generation of a pro-inflammatory response elicited by LPS-laden lipoproteins in vitro. Further, Trem2 expression regulates bone-marrow-derived macrophages (BMDMs) and Kupffer cell capacity to phagocyte apoptotic cells in vitro, which is dependent on CD14 activation. In line with this, loss of Trem2 resulted in an increased pro-inflammatory response, which ultimately aggravated liver fibrosis in murine models of NAFLD. Similarly, in a human NAFLD cohort, plasma levels of TREM2 were increased and hepatic TREM2 expression was correlated with higher levels of liver triglycerides and the acquisition of a fibrotic gene signature. Altogether, our results suggest that TREM2+ macrophages have a protective function during the progression of NAFLD, as they are involved in the processing of pro-inflammatory lipoproteins and phagocytosis of apoptotic cells and, thereby, are critical contributors for the re-establishment of liver homeostasis.

KW - Humans

KW - Mice

KW - Animals

KW - Non-alcoholic Fatty Liver Disease/metabolism

KW - Liver Cirrhosis/pathology

KW - Macrophages/metabolism

KW - Apoptosis

KW - Membrane Glycoproteins/genetics

KW - Receptors, Immunologic

U2 - 10.3390/cells12030341

DO - 10.3390/cells12030341

M3 - SCORING: Journal article

C2 - 36766683

VL - 12

JO - CELLS-BASEL

JF - CELLS-BASEL

SN - 2073-4409

IS - 3

M1 - 341

ER -