Soy hydrolysate enhances the isoproterenol-stimulated lipolytic pathway through an increase in β-adrenergic receptor expression in adipocytes

ABSTRACT

Activation of the adipose lipolytic pathway during lipid metabolism is mediated by protein kinase A (PKA), which responds to β-adrenergic stimulation, leading to increased lipolysis. Soy is well known as a functional food and it is able to affect lipolysis in adipocytes. However, the mechanism by which soy components contribute to the lipolytic pathway remains to be fully elucidated. Here, we show that hydrolyzed soy enhances isoproterenol-stimulated lipolysis and activation of PKA in 3T3-L1 adipocytes. We also found that the expression of β-adrenergic receptors, which coordinate the activation of PKA, is elevated in adipocytes differentiated in the presence of soy hydrolysate. The activity of the soy hydrolysate towards β-adrenergic receptor expression was detected in its hydrophilic fraction. Our results suggest that the soy hydrolysate enhances the PKA pathway through the upregulation of β-adrenergic receptor expression and thereby, increase lipolysis in adipocytes.

GRAPHICAL ABSTRACT

Soy hydrolysate enhances the lipolytic PKA pathway through the upregulation of β-adrenergic receptor expression in adipocytes.

KEYWORDS:

• Soy hydrolysate
• PKA
• lipolysis
• β-adrenergic receptors
• adipocyte

Acknowledgments

We are grateful to T.K. lab members for their technical support and helpful discussions.

Author contribution

W.N., T.K., and T.G. conceived the project. S.-P.N., W.N., H.T., and T.G. designed the experiments. S.-P.N., S.M., and H.N. performed the experiments. S.-P.N., W.N., S.M., H.T., H.-F.J., T.A., T.K., and T.G. discussed the results. S.-P.N. and W.N. wrote the manuscript, and all authors revised the manuscript before submission.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was partly supported by JSPS KAKENHI Grant Number 16H02551 (to T.K.), 16K07734 (to T.G.), and 18K14420 (to H.T.), and the Lotte Shigemitsu Prize, Japan (to W.N.); The Lotte Shigemitsu Prize;Japan Society for the Promotion of Science [16H02551,16K07734,18K14420].