ANGPTL3 negatively regulates IL-1ß-induced NF-κB activation by inhibiting the IL1R1-associated signaling complex assembly.

Interleukin-1ß (IL-1ß)-induced signaling is one of the most important pathways in regulating inflammation and immunity. The assembly of the receptor complex, consisting of the ligand IL-1ß, the IL-1 receptor (IL-1R) type 1 (IL1R1), and the IL-1R accessory protein (IL1RAP), initiates this signaling. However, how the IL1R1-associated complex is regulated remains elusive. Angiopoietin like 3 (ANGPTL3), a key inhibitor of plasma triglyceride clearance, is mainly expressed in the liver and exists in both intracellular and extracellular secreted forms. Presently, ANGPTL3 has emerged as a highly promising drug target for hypertriglyceridemia and associated cardiovascular diseases. However, most studies have focused on the secreted form of ANGPTL3, while its intracellular role is still largely unknown. Here, we report that intracellular ANGPTL3 acts as a negative regulator of IL-1ß-triggered signaling. Overexpression of ANGPTL3 inhibited IL-1ß-induced NF-κB activation and the transcription of inflammatory genes in HepG2, THP1, and HEK293T cells, while knockdown or knockout of ANGPTL3 resulted in opposite effects. Mechanistically, ANGPTL3 interacted with IL1R1 and IL1RAP through its intracellular C-terminal fibrinogen-like domain (FLD) and disrupted the assembly of the IL1R1-associated complex. Taken together, our study reveals a novel role for ANGPTL3 in inflammation, whereby it inhibits the physiological interaction between IL1R1 and IL1RAP to maintain immune tolerance and homeostasis in the liver.

Catheter-related superior vena cava obstruction: A rare cause of chylothorax in maintenance hemodialysis patients.

With the extensive use of dialysis catheters in patients undergoing hemodialysis, superior vena cava (SVC) syndrome has gradually attracted attention in recent years. Chylothorax caused by SVC syndrome is rarely reported. In this paper, we report a case of chylothorax secondary to superior vena cava obstruction (SVCO) in a maintenance hemodialysis patient after multiple dialysis catheter placements. Relieving the SVCO through intravascular intervention could effectively treat chylothorax. In the past fourteen months, no recurrence of symptoms has been observed.