Bscl2, encoding seipin, is a gene of great significance. Seipin is a transmembrane endoplasmic reticulum protein. It is mainly expressed in the central nervous system in humans and is associated with adipose tissue homeostasis, adipocyte differentiation, and lipid droplet morphology [1,2]. Genetic models, like KO mouse models, are valuable in studying Bscl2's functions.

Bscl2 -/- mice develop severe lipodystrophy, with only residual white and brown fat pads, validating seipin's critical role in adipose tissue homeostasis. They are also diabetic and display severe hepatic steatosis. Treatment with thiazolidinediones (TZD) increases adipose tissue mass and partially rescues metabolic complications, highlighting lipoatrophy as the major cause of the BSCL phenotype [2]. Mice with cardiomyocyte-specific deletion of Bscl2 (Bscl2cKO) develop systolic dysfunction with dilation, along with elevated ATGL expression, increased fatty acid oxidation, and reduced cardiac lipid contents. Their cardiac dysfunction can be partially reversed by a fatty acid oxidation inhibitor or prevented by certain genetic or dietary interventions [3]. A murine model for the aberrant human transcript of BSCL2 (Bscl2Celia/Celia) shows severe neurological symptoms, lipodystrophy, and mild hepatic steatosis in some affected animals, along with a reduction in brain glucose uptake and loss of Purkinje cells [4].

In conclusion, Bscl2 plays essential roles in adipogenesis, lipid droplet homeostasis, cellular triglyceride lipolysis, and cardiac lipid catabolism and contractile function. The study of Bscl2 through KO/CKO mouse models has provided insights into diseases such as Berardinelli-Seip congenital lipodystrophy, Celia's encephalopathy, and associated cardiac disorders, helping to understand the pathophysiology and potentially develop treatment strategies.