SWATH-based quantitative proteomics reveals the mechanism of enhanced Bombyx mori nucleopolyhedrovirus-resistance in silkworm reared on UV-B treated mulberry leaves

The association of ribosomal protein L18 with Newcastle disease virus matrix protein enhances viral translation and replication

ABSTRACTNumerous studies have shown that viruses can utilize or manipulate ribosomal proteins to achieve viral protein biosynthesis and replication. In our recent studies using proteomics analysis of virus-infected cells, we found that ribosomal protein L18 (RPL18) was the highest up-regulated differentially expressed protein, which was along with the increasingly expressed viral proteins later in Newcastle disease virus (NDV) infection. However, the association of RPL18 with viral protein biosynthesis and NDV replication remains unclear. In this study, we found that the expression and transcription levels of RPL18 was reduced early in NDV infection but increased later in NDV infection. In addition, the presence of cytoplasmic NDV matrix (M) protein was responsible for the increased expression of RPL18 in both virus-infected cells and plasmid-transfected cells. Moreover, cytoplasmic M protein increased RPL18 expression in a dose-dependent manner, even though they did not interact with each other. Furthermore, siRNA-mediated knockdown of RPL18 or overexpression of RPL18 dramatically reduced or enhanced NDV replication by decreasing or increasing viral protein translation rather than viral RNA synthesis and transcription. Taken together, these results suggested that the increased expression of RPL18 might be associated with the physical clumping together of the M protein, which in turn promoted viral protein biosynthesis and NDV replication, thus revealing for the first time the association of RPL18 with NDV M protein was important for viral translation and replication.

A Novel Benzofuran Derivative Moracin N Induces Autophagy and Apoptosis Through ROS Generation in Lung Cancer

Introduction

The leaves of Morus alba L is a traditional Chinese medicine widely applied in lung diseases. Moracin N (MAN), a secondary metabolite extracted form the leaves of Morus alba L, is a potent anticancer agent. But its molecular mechanism remains unveiled.

Objective

In this study, we aimed to examine the effect of MAN on human lung cancer and reveal the underlying molecular mechanism.

Methods

MTT assay was conducted to measure cell viability. Annexin V-FITC/PI staining was used to detect cell apoptosis. Confocal microscope was performed to determine the formation of autophagosomes and autolysosomes. Flow cytometry was performed to quantify cell death. Western blotting was used to determine the related-signaling pathway.

Results

In the present study, we demonstrated for the first time that MAN inhibitd cell proliferation and induced cell apoptosis in human non-small-cell lung carcinoma (NSCLC) cells. We found that MAN treatment dysregulated mitochondrial function and led to mitochondrial apoptosis in A549 and PC9 cells. Meanwhile, MAN enhanced autophagy flux by the increase of autophagosome formation, the fusion of autophagsomes and lysosomes and lysosomal function. Moreover, mTOR signaling pathway, a classical pathway regualting autophagy, was inhibited by MAN in a time- and dose-dependent mannner, resulting in autophagy induction. Interestingly, autophagy inhibition by CQ or Atg5 knockdown attenuated cell apoptosis by MAN, indicating that autophagy serves as cell death. Furthermore, autophagy-mediated cell death by MAN can be blocked by reactive oxygen species (ROS) scavenger NAC, indicating that ROS accumulation is the inducing factor of apoptosis and autophagy. In summary, we revealed the molecular mechanism of MAN against lung cancer through apoptosis and autophagy, suggesting that MAN might be a novel therapeutic agent for NSCLC treatment.