Silkworm Hemolymph Down-Regulates the Expression of Endoplasmic Reticulum Chaperones under Radiation-Irradiation

Kyeong Ryong Lee,Young Kook Kim,Kweon Yu,Seung-Whan Kim,O-Yu Kwon,Kisang Kwon,Jong-Soon Choi

doi:10.3390/ijms12074456

Abstract

We demonstrated that up-regulation of gene expression of endoplasmic reticulum (ER) chaperones (BiP, calnexin, calreticulin, ERp29) and ER membrane kinases (IRE1, PERK, ATF6) was induced by radiation in neuronal PC12 cells. However, addition of silkworm, Bombyx mori, hemolymph to irradiated cells resulted in an obvious decrease in expression of these genes, compared with a single radiation treatment. In contrast, one of the ER chaperones, “ischemia-responsive protein 94 kDa” (irp94), was up-regulated by radiation. However, addition of silkworm hemolymph resulted in no change in the expression of irp94, with an expression pattern that differed from that of ER chaperones. Based on these results, we propose that silkworm hemolymph contains factors that regulate a decrease in the expression of ER chaperones under radiation-irradiation conditions, with the exception of irp94, which is not down-regulated. We suggest that this difference in the molecular character of irp94 may provide a clue to the biological functions associated with ER stress pathways, particularly the effects of radiation.

Highlights

The endoplasmic reticulum (ER), a eukaryotic organelle, is the location of post-translational modification
The effect of various doses of radiation on binding protein (BiP) expression was assessed in PC12 cells by RT-PCR, and no evidence noting remarkable changes of ER chaperone BiP by
We tested whether B. mori hemolymph directly regulated the expression of unfolded protein response (UPR) molecules, and the dose-dependent effect on gene expression and induction of apoptosis according to previous data [22,23]

Summary

Introduction

The endoplasmic reticulum (ER), a eukaryotic organelle, is the location of post-translational modification. We are interested in the effect of silkworm hemolymph on gene expression of ER chaperones under radiation-irradiation in PC12 cells. We would like to determine whether radiation-irradiation induces expression of ER chaperones, and how silkworm hemolymph affects gene expression under such conditions. We would like to determine whether the molecular behavior of irp[94] to both radiation-irradiation and silkworm hemolymph is the same as those of ER chaperones in the PC12 cell. This may provide clues to understanding irp[94] molecular features associated with extracellular stressors, including ER stress and radiation

Results and Discussion

Cell Culture and Radiation Exposure

Silkworm Hemolymph Collection

Semiquantitative RT-PCR

Conclusions