Adrb3, also known as β3-adrenergic receptor, is mainly expressed in brown adipose tissue (BAT). It can activate BAT, participating in energy metabolism-related pathways such as lipolysis and thermogenesis in adipose tissue, and is crucial for metabolic health [1,2,4,5,6]. Genetic models like KO mouse models are valuable for studying its functions.

In a brown adipocyte-specific ADRB3 knockout (BKO) mouse model, BKO mice showed accelerated cardiac hypertrophy and fibrosis compared with control mice after Ang II infusion. This indicates that ADRB3 in brown adipocytes offers cardiac protection through suppressing exosomal iNOS, revealing a new endocrine pattern of BAT in regulating cardiac remodeling [1]. Also, in ADRB3-/-PyMT mice, the MDSC-deficient phenotype was associated with impairment of mammary tumorigenesis and reduction in pulmonary metastasis, suggesting that ADRB3 promotes metastasis by inducing mobilization and inhibiting differentiation of both breast cancer cells and myeloid-derived suppressor cells (MDSCs) [3].

In conclusion, Adrb3 is essential for metabolic health, playing a role in energy-related biological processes. Through gene-knockout mouse models, it has been found to be involved in cardiac remodeling and tumor metastasis, providing valuable insights into the mechanisms of related diseases and potential therapeutic targets.