Impact of <i>Celosia cristata</i> Extract on Adipogenesis of Native Human CD34⁺/CD31^- Cells

Abstract

Background : The adipose tissue mainly consists of adipocytes but also contains non-adipose cells. Among them, progenitor cells represent a local pool of immature cells that, in vitro , can undergo various lineage differentiation processes. These cells are thought to contribute to normal homeostasis of the adipose tissue through adipogenesis but also to the growth of the adipose tissue under chronic energy overload. The aim of the present study is to evaluate in vitro the capacity of a Celosia cristata extract to impact the adipogenic potential of native human adipose tissue progenitor cells, i.e. commitment and differentiation towards adipogenic lineage. Methods : Native adipose tissue progenitor cells were isolated by immunoselection/depletion approaches from human subcutaneous adipose tissues. Two distinct cell culture conditions were used to assess the effect of Celosia cristata extract on commitment and differenciation of progenitor cells. Cells were cultured either in differentiation medium for 10 days in the presence/absence of Celosia cristata extracts to study the impact on differentiation or first cultured in a commitment-inducing medium, with or without Celosia cristata extract, for 48 h and then cultured 10 days in differentiation medium to assess the impact on commitment. In both experimental series, the fate of progenitor cells was studied by quantification of lipids and by determining the expression of key genes involved in adipogenesis. Results : Data show that Celosia cristata extract reduces lipid content of progenitor cells undergoing differentiation. This reduction correlates with a reduced expression of C/EBP α . When progenitor cells are placed in commitment-inducing conditions, Celosia cristata extract induces a more potent reduction of lipid content. This reduction correlates with a decrease in the expression levels of master genes involved in adipogenesis: the genes of transcription factors PPAR γ 2 and C/EBP α as well as marker genes coding for LPL and GPDH. Conclusions : Celosia cristata extract decreases adipogenesis. The effect of the extract is stronger when studying commitment and differentiation than differentiation alone; it suggests that the extract impact the commitment of human adipose tissue progenitor cells.