Cirrhosis‐downregulated LSECtin can be retrieved by cytokines, shifts the TLR‐induced LSECs secretome and correlates with the hepatic Th response

Abstract Background and Aims We evaluated tolerogenic C‐type lectin LSECtin loss in cirrhosis and its potential regulation by cytokines. Methods Liver tissue from patients with cirrhosis and healthy controls, immortalised and generated LSECtin‐CRISPR immortalised LSECs, and murine primary LSECs from the CCl 4 model were handled. Results LSECtin expression was reduced in liver tissue from cirrhotic patients, and it decreased from compensated to decompensated disease. Increased phosphorylation of MAPK, Akt and NFkB was observed upon LSECtin stimulation in LSEC murine cell line, showing a pattern of inflammatory and chemotactic cytokines either restrained (IL‐10, CCL4) or unrestrained (TNF‐α, IL‐1β, IL‐6, CCL2). CD44 attenuated whereas LAG‐3 increased all substrates phosphorylation in combination with TLR4 and TLR2 ligands except for NFkB. TNF‐α, IL‐1 β, IL‐6 and CCL2 were restrained by LSECtin crosslinking on TLRs studied. Conversely, IL‐10 and CCL4 were upregulated, suggesting a LSECtin‐TLRs synergistic effect. Also, LSECtin was significantly induced after IL‐13 stimulation or combined with anti‐inflammatory cytokines in cirrhotic and immortalised LSECs. Th17 and regulatory T cells were progressively increased in the hepatic tissue from compensated to decompensated patients. A significant inverse correlation was present between gene expression levels of CLEC4G/LSECtin and RORγT and FOXP3 in liver tissues. Conclusion LSECtin restrains TLR proinflammatory secretome induced on LSECs by interfering immune response control, survival and MAPKs signalling pathways. The cytokine‐dependent induction of LSECtin and the association between LSECtin loss and Th17 cell subset expansion in the liver, provides a solid background for exploring LSECtin retrieval as a mechanism to reprogram LSEC homeostatic function hampered during cirrhosis.