Brown adipocyte and browning thermogenesis: metabolic crosstalk beyond mitochondrial limits and physiological impacts.

Brown adipocytes were proposed to reverse metabolic conditions such as obesity and diabetes, which make them potential for therapeutic applications. Brown adipocytes and browning process are capable of thermogenesis, the uncoupling metabolism which allows them to promote balanced energy expenditure, a fundamental mechanism for improving metabolic disorders. Thermogenesis process is not only performed by the thermogenin UCPs within the mitochondria, but instead, is globally regulated within brown and browning adipose tissues, which induces signalling molecules that can be sent to nearby and distant tissues to generate systemic effects on metabolism. This review highlights thermogenesis and describes the crosstalk between different organelles within browning and brown adipocytes, as well as their interorgan axes to regulate whole body metabolism. Finally, browning and thermogenesis activation will also be discussed in terms of physiological conditions, in which, we propose that thermogenesis and functional activities of brown adipocytes should be considered individually in future clinical application.