Three-dimensional adipocyte cultures and co-cultures to study tissue interactions

Abstract

Adipocytes play many important roles within the body, though until recently their importance has frequently gone unrecognised. They are well known for their activities in fat metabolism and storage, but they are also significant secretory cells, and play roles in modulating immune function and provisioning stem cell development. Different adipose depots are specialised to interact in different ways with neighbouring cells, tissues and organs, and there is now an emerging body of evidence demonstrating their roles in areas as diverse as gut function, immune function and cardiac function. Adipocytes are difficult to study in conventional culture: their buoyant density is such that they float, so are easily lost during medium changes, and their large size makes them too fragile to withstand many routine manipulations. When they lyse they release quantities of triacylglycerols which interfere with many biochemical analyses. Thus much of the work on adipocytes has had to be carried out in vivo. We have developed a 3D culture system in which preadipocytes are differentiated to functional, mature adipocytes which retain many of the properties of ex vivo adipocytes. The adipocytes remain in place during medium changes, and their secretory activities can be monitored by assaying culture supernatants. Moreover, the culture conditions are mild, and flexible enough to accommodate co-cultures with cells requiring different culture conditions. It is therefore an ideal system for studying the interactions between adipocytes and other cell types that underpin tissue and organ function