Fibroblast growth factor 2 differentially influences leptin gene expression in dispersed adipose tissue cell cultures

Abstract

Re-establishing vasculature is an essential component to the wound healing process, as it is a mechanism for provision of substrates required for tissue repair. Due to the potent angiogenic properties of adipose tissue, the application of extract from ground subcutaneous fat has been utilized to facilitate angiogenesis to promote healing. Nearly all angiogenic processes are regulated through growth factors such as angiopoietin, vascular endothelial growth factor, and fibroblast growth factor (FGF). Fibroblast growth factor belongs to a family of 23 members that is involved in many physiological processes including cellular proliferation and morphological differentiation. Specifically, FGF2 facilitates vascular endothelial cell proliferation, migration, and differentiation required in vessel sprout formation. Interestingly, FGF2 is synthesized and secreted by adipocytes, a cell that also produces leptin, another potent angiogenic factor. Therefore, it is hypothesized that FGF2 stimulates leptin gene expression in adipose tissue cells. In exp 1, subcutaneous adipose tissue was collected from 4 prepubertal female pigs and enzymatically dispersed (collagenase type II) to separate mature adipocytes (MA) from all other cell types (AOC; vascular endothelial cells (VEC), preadipocytes, fibroblasts) in preparation for treatment. The MA and AOC cells were treated with porcine FGF2 (0, -11, -10, -9 M). In exp 2, subcutaneous adipose tissue was collected 6 prepubertal female pigs and processed as in exp. 1; however, following processing, MA and AOC were combined and treated with FGF2 (-11M) or FGF2 polyclonal antibody (1:100 dilution). Real time PCR was used to measure the expression of target genes and SAS was utilized to determine the effect of treatment on gene expression. In exp 1, FGF2 augmented leptin gene expression in cultured MA (P=0.03). In contrast, FGF2 did not appear to influence leptin gene expression in MA and AOC co-cultures, despite the detection of a significant decrease in the expression of FGF receptor 2 (P=0.05). In conclusion, FGF2 influences leptin gene expression in MA; however, this may be mitigated/altered through the interaction with different adipose tissue cells.