Like pigs, and unlike other breeds of cattle examined, mature Angus-derived adipocytes may extrude lipid prior to proliferation in vitro

Abstract

A large number of studies have shown that mature adipocytes are able to dedifferentiate in vitro into progeny cells, which possess proliferative capacity and mutilineage potential. Our present study confirms that mature adipocytes derived from Angus cattle also dedifferentiate into proliferative-competent progeny cells. However, this report is unlike any published for all other breeds of cattle we have worked with or that we have seen in published reports, in which mature adipocytes retain and distribute lipids into daughter cells symmetrically or asymmetrically. In the present work, we noted that Angus-derived mature adipocytes extruded a majority of their cellular lipid droplets prior to cell division. In this manner, these cells are processing lipid in a manner observed in mature adipocytes isolated from swine tissue. These results suggest that regulation of the mechanism(s) underlying lipid processing might be different between and within animal breeds. Lipid processing in beef-derived adipocytes during dedifferentiation may serve as a unique animal model for studying lipid metabolism during reverse adipogenesis.

Keywords: cattle; dedifferentiation; lipids; mature adipocytes; proliferation.

Figure 1. Lipid handing manner during dedifferentiation of pig-derived mature adipocyte. Pig-derived mature adipocyte extruded lipid prior to proliferation. Isolation method was described by Chen et al.^, [(A–C), 200× magnification; (D), 100× magnification; in time order.]

Figure 2. Lipid processing during dedifferentiation of purified cultures of mature adipocytes derived from Angus cattle. At the end of ceiling culture, mature adipocytes appeared like a spindle-shaped oval (A). One day after reinverting the flask the lipid-filled adipocyte began to enlarge and adhered tightly to the flask surface (B). Two days after reinverting the flask the cell membrane spreaded significantly and a large lipid droplet was extruding into the medium (C). Eight days after reinverting the flask, lipid has been expelled, and the cells proliferated into a number of daughter cells in vitro (D). [(A–C), 200× magnification; (D), 100× magnification.]