Stabilin1 mediates ingestion of oxidized erythrocytes by LSECs (efferocytosis)

Backgrounds: Previous studies have identified hemolysis as an important predictor for survival in patients with alcohol-related liver disease (ALD). Here we aimed to study the role of liver sinusoidal endothelial cells (LSEC) on the clearance (efferocytosis) of oxidized red blood cells (RBC).

Methods: Real-time live videos of LSEC efferocytosis were taken using incuCyteS3. Protein and mRNA levels of HO-1, Nrf2, and stabilin-1 were measured by qPCR and immunoblotting. Stabilin-1 was knocked down using siRNA. LSEC efferocytosis was further studied in a mouse model of chronic ethanol exposure and in an in vivo hemolysis model using phenylhydrazine (PHZ) by immunofluorescence and immunohistochemistry.

Results: Live microscopy demonstrates that oxidized RBCs are rapidly ingested by LSECs, followed by induction of HO-1 and its upstream regulator Nrf2. In addition, LSEC efferocytosis was mediated by scavenging receptors such as Stabilin-1. Silencing of endothelial Stabilin-1 partially blocked efferocytosis by 50%. Efferocytosis could also be induced by hemin and lysed RBC. In a PHZ-induced hemolysis and a chronic ethanol mouse model, uptake of RBCs by LSECs could be confirmed using immunofluorescence staining. RBCs could be primed for efferocytosis using ethanol starting from levels as high as 25 mM. Finally, we show in a cohort of heavy human drinkers (n=34) that hepatic Stabilin-1 mRNA highly correlates with mRNA of HO-1 and Nrf2 (r=, P<0.05).

Conclusion: We here show that oxidized and ethanol primed RBCs are rapidly taken up by LSECs, a process that is likely to contribute to hemolysis in ALD.

Publication History

Article published online:
20 January 2025