Basic fibroblast growth factor (bFGF) contributes to the enlargement of brown adipose tissue during cold acclimation

Abstract

The contribution of basic fibroblast growth factor to brown adipose tissue (BAT) enlargement during cold acclimation was investigated using rat brown adipocytes in primary culture. After cold exposure (at 5 degrees C) for 28 days, the level of bFGF messenger ribonucleic acid (mRNA) in BAT of cold-acclimated rats was markedly increased with the increase in the BAT weight. In addition, the blood plasma from cold-acclimated rats considerably enhanced the expression of basic fibroblast growth factor mRNA in rat brown adipocytes. Likewise, the blood plasma from cold-acclimated rats significantly stimulated the growth of rat brown adipocyte precursor cells compared with that from warm-acclimated rats, whereas there was no difference of effect between the two blood plasmas on the growth of bovine capillary endothelial cells. Basic fibroblast growth factor, but not platelet-derived growth factor stimulated the growth of brown adipocyte precursor cells. The conditioned medium from brown adipocyte primary culture markedly stimulated the growth of bovine capillary endothelial cells and the effect was inhibited considerably by antibasic fibroblast growth factor antibody. These results suggest that some factors concerned with the growth of brown adipocyte precursor cells are present in the blood plasma from cold-acclimated rats, and that basic fibroblast growth factor produced by brown adipocytes may significantly contribute to BAT enlargement by autocrine mechanisms during cold exposure.

Multiple symmetric lipomatosis: clinical aspects and outcome in a long-term longitudinal study

“…21,22 Moreover, cultured MSL cells were characterised by a high basic fibroblast growth factor (b-FGF) stimulated proliferation rate, 23 and b-FGF has been demonstrated to contribute to the enlargement of BAT during cold acclimation. 24 Furthermore, fatty tumours in MSL grows mainly through a cell proliferation process, 4 and the malignant degeneration of MSL lipomatous tissue has also been reported. 9,25 Bundles of microfilaments and nuclear pockets, both suggesting a neoplastic-like proliferation process, have been observed in MSL cultured cell.…”

Growth factor regulation of uncoupling protein-1 mRNA expression in brown adipocytes

“…Thus growth factors like aFGF and bFGF, besides being potent mitogens for brown adipocytes, allow differentiation. One of those growth factors, bFGF, has been shown to be involved in BAT enlargement during cold acclimation (34), and its expression is greatly enhanced in response to NE (35). These findings, in addition to our results, confirm that bFGF is an important growth factor for brown fat cell proliferation and differentiation.…”

Norepinephrine Induces Vascular Endothelial Growth Factor Gene Expression in Brown Adipocytes through a β-Adrenoreceptor/cAMP/Protein Kinase A Pathway Involving Src but Independently of Erk1/2

“…9) and thus not dependent on protein synthesis. Thus, although NE may induce the gene expression of certain transcription factors (such as hypoxia-inducible factor-1␣), 5 such induction cannot be involved in the mediation of the NE effect. The lack of need for protein synthesis is also in accordance with observations in other systems, with other inducers of VEGF expression (46,49).…”

“…The regulation of this angiogenesis in brown adipose tissue has so far not been extensively investigated. Expression of the angiogenic factor basic fibroblast growth factor, is induced in the tissue by cold exposure (5) and by NE in cultured brown adipocytes (6). The VEGF-related factor (vascular endothelial growth factor-B) is expressed already during development (7), and expression of VEGF (vascular endothelial growth factor (8)) itself is induced by NE administration and cold exposure in brown adipose tissue (9), and VEGF expression and secretion is stimulated by NE in cultured brown adipocytes (10,11).…”