Extract of Paecilomyces hepiali mycelia induces lipolysis through PKA-mediated phosphorylation of hormone-sensitive lipase and ERK-mediated downregulation of perilipin in 3T3-L1 adipocytes

Abstract

BackgroundCordyceps sinensis has been used for centuries in China as one of the most valued herbal medicine and tonic food. Paecilomyces hepiali, a fungal strain isolated from natural C. sinensis, has been used widely as a substitute of C. sinensis in medicine and health food. P. hepiali has been reported to have various pharmaceutical benefits, including triglyceride-lowing activity. However, its effects on triglyceride metabolism in adipocytes remain unknown. The purpose of the present study was to evaluate the effect of P. hepiali mycelia on adipocyte lipolysis and to clarify the underlying mechanisms.MethodsThe fully differentiated 3T3-L1 adipocytes were treated with methanol extract of Paecilomyces hepiali mycelia (PHME). Contents of glycerol released into the culture medium and intracellular triglyceride were measured as indices of lipolysis using glycerol assay kit and Oil red O staining, respectively. Then, effects of PHME on the main lipases or kinases involved in lipolysis regulation were investigated. Protein expression of adipose triglyceride lipase (ATGL) and perilipin, as well as phosphorylation of hormone-sensitive lipase (HSL), AMP-activated protein kinase (AMPK), and mitogen-activated protein kinases (MAPKs) were determined by western blotting. Moreover, nucleosides, important constituents of PHME, were analyzed using high performance liquid chromatography (HPLC).ResultsTreatment with PHME led to a significant increase in glycerol release thereby reduced intracellular triglyceride accumulation in fully differentiated adipocytes. PHME upregulated protein kinase (PK) A-mediated phosphorylation of HSL at serine residues of 563 and 660. Meanwhile, PHME treatment also upregulated phosphorylation of extracellular signal-regulated kinase (ERK), and downregulated the protein level of perilipin. Pretreatment with the PKA inhibitor, H89, blunted the PHME-induced lipolysis and the phosphorylation of HSL (Ser 563 and 660). Moreover, pretreatment with ERK inhibitor, PD98059, weakened the PHME-caused glycerol release and downregulation of perilipin expression. HPLC analysis indicated there were adenosine, cordycepin, uridine and vernine in PHME.ConclusionsOur results showed that PHME significantly induced lipolysis in 3T3-L1 adipocytes, which is mainly mediated by activation of HSL through PKA pathway and by downregulation of perilipin through activation of ERK pathway.Electronic supplementary materialThe online version of this article (10.1186/s12906-018-2389-0) contains supplementary material, which is available to authorized users.

Adropin Slightly Modulates Lipolysis, Lipogenesis and Expression of Adipokines but Not Glucose Uptake in Rodent Adipocytes

“…Our data indicate that adropin failed to affect Hsl mRNA levels but enhanced the phosphorylation of HSL at serine 563. It is worth noting that the phosphorylation of HSL at serine 563 is promoted by lipolysis-inducing factors [19,[26][27][28]. These results provide evidence that adropin may modulate lipolysis to a slight extend by activating HSL in white adipocytes.…”

Mutual impact of adipocytes and colorectal cancer cells growing in co-culture conditions

“…We also found elevated levels of phosphorylated ERK (extracellular signal-regulated kinase, MW 44/42 kDa) and STAT3 (signal transducer and activator of transcription 3, MW is 91 kDa) (Fig. 2 B), which may participate in the lipolysis process [ 25 , 26 ]. However, this alteration can be better described as a trend (except for pSTAT3/STAT3 in HCT116/AD).…”

“…Another pathway involved in lipolysis might be the ERK pathway, which also takes part in the adipogenesis process. Activation of this kinase is an early signal for the reduction of the perilipin protein level [ 26 ], so our observation of enhanced phosphorylation of ERK may be connected with the decreased expression level of perilipin . This protein is located on the surface of lipid droplets and protects them from the access of lipases [ 43 ].…”

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“…6; generated using Adobe Illustrator CC version 23.0; Adobe Systems, Inc.). HSL is a critical rate-limiting enzyme of adipose degradation and is responsible for the breakdown of TG and cholesteryl esters into glycerin, fatty acid and cholesterol in the adipose tissue, which are then released into the blood (72). Therefore, inhibition of the cAMP signaling pathway can decreases the phosphorylation of HSL to reduce the content of blood TC and TG.…”