Effect of the silencing of TNF alpha and glycine receptors on the secretion of pro-inflammatory cytokines in 3T3-L1 preadipocytes

Abstract

ABSTRACT: Obesity has been related to a process of chronic inflammation, which is characterized by an increase in pro-inflammatory cytokine levels. It has been reported that glycine decreases the secretion of TNF alpha and IL-6 in adipocytes, although the mechanisms have not yet been clarified. The purpose of this study was to determine the mechanism by which glycine reduces the secretion of TNF alpha and IL-6 using siRNA from the TNF alpha and glycine receptors.

METHODS: Several types of glycine receptors were characterized by RT-PCR. 3T3-L1 cells were transfected with siRNA for glycine receptor; three days later, the cells were ready for the experiments. 3T3-L1 cells was treated with Glycine 10 mM. Total RNA was extracted from the cells for the determination of TNF alpha and IL-6 expression by RT-PCR; in addition, the concentration of these cytokines in the medium was quantified by ELISA.

RESULTS: Glycine decreased the production and release of TNF alpha and IL-6, whereas treatment with siRNA for the TNF alpha and glycine receptors produced increases in the secretion of the levels of these cytokines.

CONCLUSION: These findings give clues about the signaling mechanisms by which glycine inhibits the secretion of pro-inflammatory adipokines in obesity.