Increasing vimentin expression associated with differentiation of human and rat preadipocytes.

Alterations in the cytoskeletal apparatus constitute some of the earliest changes during assumption of an adipogenic phenotype. We examined three major cytoskeletal elements, beta-actin, alpha-tubulin and vimentin, during adipogenesis in euploid cells from human and rat adipose tissue. As reported with 3T3 sub-lines, mRNA level for beta-actin and alpha-tubulin were decreased upon differentiation. However, in contrast to reports with 3T3 cells, levels of vimentin were increased during differentiation. Furthermore, immunological analyses confirmed that there was no decrease in vimentin protein levels during adipogenic development. As well as highlighting a difference between 3T3 cell lines and preadipocytes isolated from fat depots, these studies indicate that the pattern of cytoskeletal gene expression undergoes complex changes early during preadipocyte differentiation.