Cellular and molecular basis of adipose tissue development: from stem cells to adipocyte physiology

White adipose tissue plays a key role in the regulation of energy balance in vertebrates. Its primary function is to store and release energy. It is also recognized to secrete a variety of factors called adipokines that are involved in a wide range of physiological and metabolic functions. Unlike other tissues, adipose tissue mass has large capacity to expand and can be seen as a dynamic tissue able to adapt to a variety of environmental and genetic factors. The aim of this review is to update the cellular and molecular mechanisms associated with adipose tissue growth and development in domestic animals, with a special focus on the pig. In contrast to other tissues, the embryonic origin of adipose cells remains the subject of debate. Among the variety of cell types contained in adipose tissue, we highlight recent data dealing with adipose-derived stromal stem cells that contribute to tissue homeostasis. The relationships between the proportions of the different stem cells and other molecular indicators of adipose tissue functions are investigated. The current knowledge on the dynamic expression of genes involved in cell cycle arrest, differentiation, and physiology during fetal development is summarized to determine how these changes may be linked to newborn survival. Both genetics and nutrients can affect these processes; they also influence the postnatal growth of adipose tissue. In brief, a better understanding of the developmental biology of adipose tissue is of great importance for targeting this tissue in the animal production held