Inhibition of Human Cell Apoptosis by Silkworm Hemolymph

Abstract

Many studies on preventing apoptosis have been carried out from the viewpoint of anti-apoptotic cloned-gene expressions inside cells, whereas in this study, we investigated the inhibition of apoptosis by the addition of silkworm hemolymph, a natural compound, from outside of the cells. In a previous study, we reported the inhibition effect of silkworm hemolymph on the baculovirus-induced insect cell apoptosis. Using the vaccinia virus-HeLa cell system as a model system in this study, we found that silkworm hemolymph, the insect serum, inhibits apoptosis not only in the insect cell system but also in the human cell system. The vaccinia virus-induced HeLa cell apoptosis was analyzed using DNA electrophoresis, TUNEL, and flow cytometry, and the resulting data confirmed that silkworm hemolymph inhibits human cell apoptosis. The inhibition of apoptosis due to silkworm hemolymph was not caused by an inhibition of virus binding and internalization steps, nor did silkworm hemolymph interfere with the virus production. The inhibition of apoptosis by silkworm hemolymph decreased the cell detachment from an adhering surface. With these characteristics, silkworm hemolymph can be effectively used to minimize cell death in commercial animal cell culture.

Performance evaluation of CHO-K1 cell in culture medium supplemented with hemolymph

“…FBS is a costly component, accounting for about 90% of the cost when the medium is supplemented with 10% FBS (Murhammer et al, 1988), whereas silkworm hemolymph is very cheap and can be easily collected since the silkworm is an insect easily available that can be used to produce commercial quantities of hemolymph (Ha et al, 1996). Besides, hemolymph has an inhibitory effect on apoptosis, a programmed form of cell death, as much in insect cells as in animal cells (Ha et al, 1997 andChoi et al, 2002) and when utilized as a substitute for FBS it can enhance the recombinant protein expression (Kim et al, 1999). If a supplement with this characteristic is added to commercial medium and used in animal cell bioprocessing, it should significantly improve productive efficiency and the product's final cost.…”

The Mulberry Silkworm—A New Source of Bioactive Proteins

“…The addition of silkworm haemolymph to cell cultures inhibits apoptosis and improves viability of the cells. To this date, anti-apoptotic properties of haemolymph were proven for insect, Sf9 [44][45][46][47], mammalian, CHO [48,49] and human cell lines, HeLa [50] and HEK293 cell line [48]. Additionally, apoptosis inhibition by haemolymph resulted in a five-fold increase of erythropoietin production in the CHO cell culture [49].…”

“…Silkworm haemolymph could be efficiently used for apoptosis inhibition in commercial cell cultures and improve their productivity [50,48]. Silkworm haemolymph could serve as a medium supplement and replace commonly used fetal bovine serum [51].…”

“…Silkworm haemolymph could serve as a medium supplement and replace commonly used fetal bovine serum [51]. Moreover, silkworm haemolymph does not interact with viruses [50], which are often used as infective expression vectors for the production of recombinant proteins in cell cultures [52,53]. Finally, some haemolymph proteins could be used in the future to treat diseases related to hyperactive apoptosis [48].…”

Effects of matured silkworm hemolymph on suppressing melanin synthesis

“…이와 같은 부작용을 완화시키 기 위한 방편으로 친환경 소재 개발 연구가 진행되고 있 으며 특히, 여러 천연 물질들의 미백, 항산화, 항균, 보습 효과 등이 과학적으로 입증되면서 이들에 대한 연구가 확 대되고 있다 (Mukherjee et al 2011, Choi et al 2010 (Yeo et al 2000, Dash et al 2008, Lee et al 2001 (Zhang et al 2011, Kim et al 2003, Choi et al 2002. (Fig.…”