Proteasome activator REGγ promotes inflammation in Leydig cells via IkBε signaling

REGγ promotes mantle cell lymphoma cell apoptosis by downregulating NF-κB signaling

Background

Mantle cell lymphoma (MCL) is an aggressive B-cell non-Hodgkin lymphoma (NHL). REGγ is important for tumor occurrence and development, but understanding of the specific role of REGγ in MCL is lacking. We aimed to identify REGγ effects on the proliferation and apoptosis of MCL cells and clarify the underlying mechanisms.

Methods

JEKO-1 cells stably transfected with a doxycycline-inducible Tet-On system expressed high levels of REGγ. JEKO-1 cells stably expressing shRNA-REGγ to reduce REGγ levels were constructed. Cell proliferation, apoptosis, and p-NF-κB, NF-κB, IkB, REGγ, p-STAT3, STAT3, and PSMB5 levels in transfected cells and in transfected cells treated with Stattic, that is a nonpeptidic small molecule exhibited to selectively inhibit signal transducer and activator of transcription factor 3 through blocking the function of its SH2 domain, were analyzed using western blotting.

Results

The proliferation of JEKO-1 cells was inhibited, and apoptosis was enhanced by increased expression of REGγ (P<0.01). REGγ inhibited MCL cell proliferation in a mouse tumor xenograft model by promoting apoptosis, increased the expression of the three IκB subunits and inhibited NF-κB signaling. Overexpressed REGγ inhibited STAT3 and downregulated PSMB5 expression in MCL cells. Stattic downregulated PSMB5 and nuclear factor-kappa B (NF-κB) expressions and upregulated IκBε expression in JEKO-1 cells.

Conclusions

We found that REGγ regulated p-STAT3 expression by accelerating its half-life and downregulated the NF-κB signaling pathway to promote MCL cell apoptosis by negatively regulating STAT3-mediated PSMB5 expression and subsequently upregulating IκB expression.

Screening of the Active Component Promoting Leydig Cell Proliferation from Lepidium meyenii Using HPLC-ESI-MS/MS Coupled with Multivariate Statistical Analysis

Lepidium meyenii is now widely consumed as a functional food and medicinal product, which is known as an enhancer of reproductive health. However, the specific chemical composition and mechanism of action for improving sexual function are unclear. The present study aims at screening and determining the potential compounds, which promote mouse leydig cells (TM3) proliferation. The partial least squares analysis (PLS) was employed to reveal the correlation between common peaks of high performance liquid chromatography (HPLC) fingerprint of L. meyenii and the proliferation activity of TM3. The results suggested that three compounds had good activities on the proliferation of TM3 and promoting testosterone secretion, there were N-benzyl-hexadecanamide, N-benzyl-(9z,12z)-octadecadienamide and N-benzyl-(9z,12z,15z)-octadecatrienamide which might be the potential bioactive markers related to the enhancing sexual ability functions of L. meyenii. The first step in testosterone synthesis is the transport of cholesterol into the mitochondria, and the homeostasis of mitochondrial function is related to cyclophilin D (CypD). In order to expound how bioactive ingredients lead to promoting testosterone secretion, a molecular docking simulation was used for further illustration in the active sites and binding degree of the ligands on CypD. The results indicated there was a positive correlation between the binding energy absolute value and testosterone secretion activity. In addition, in this study it also provided the reference for a simple, quick method to screen the promoting leydig cell proliferation active components in traditional Chinese medicine (TCM).