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Destruxin A Induces and Binds HSPs in Bombyx mori Bm12 Cells
Huanhuan Zhang1, Weina Hu1, Miaomiao Xiao1
1Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, College of Agriculture, South China Agricultural University , Guangzhou 510642, China.
Abstract:
Destruxin A (DA) is a cyclodepsipeptidic mycotoxin isolated from the entomopathogenic fungus, Metarhizium anisopliae. It has insecticidal activity against host insect's innate immunity system, but the molecular mechanism is not yet elucidated. In our previous experiment, four HSPs (heat shock proteins, BmHSP70-3, BmHSP75, BmHSP83, and BmHSCP) were characterized from the specific protein electrophoretic bands of Bombyx mori Bm12 cell line treated with DA in the test of drug affinity responsive target stability (DARTS), which implied that these HSPs might be kinds of DA-affinity proteins, or DA induces them up-regulated expression. Therefore, in current research, the interactions of DA and HSPs were explored through analysis of bio-layer interferometry (BLI) employing FortBio OcteteQK. The expression levels of HSPs genes were surveyed by quantitative real-time polymerase chain reaction (qPCR). The results indicated that DA had no interactions with BmHSP70-3, BmHSP75, and BmHSP83, but had affinity to BmHSCP with a KD value of 88.1 μM, in BLI analysis. However, the expression levels of all HSPs genes were significantly up-regulated after the Bm12 cells were treated by DA. In conclusion, DA can induce the four HSPs expression in Bm12 cells, but DA only binds to BmHSCP. Our research provides new insights on understanding of the action mechanisms of destruxins.
Insights
Destruxin A (DA) up-regulates four heat shock proteins (HSPs) in Bombyx mori cells. While DA only directly binds to BmHSCP, it induces expression of all four HSPs, offering insights into its insecticidal mechanisms.
Area of Science:
- Toxicology
- Molecular Biology
- Entomology
Background:
- Destruxin A (DA) is a mycotoxin from Metarhizium anisopliae with insecticidal properties.
- The molecular mechanisms underlying DA's effects on insect immunity are not fully understood.
- Previous studies suggested potential interactions between DA and heat shock proteins (HSPs) in Bombyx mori cells.
Purpose of the Study:
- To investigate the direct binding interactions between DA and specific HSPs (BmHSP70-3, BmHSP75, BmHSP83, BmHSCP).
- To determine the effect of DA on the gene expression levels of these HSPs in Bombyx mori Bm12 cells.
Main Methods:
- Bio-layer interferometry (BLI) was used to analyze the binding affinity between DA and purified HSPs.
- Quantitative real-time polymerase chain reaction (qPCR) was employed to measure the expression levels of HSP genes after DA treatment.
Main Results:
- BLI analysis revealed that DA directly binds only to BmHSCP, with a dissociation constant (KD) of 88.1 μM.
- DA treatment significantly up-regulated the gene expression of all four investigated HSPs (BmHSP70-3, BmHSP75, BmHSP83, and BmHSCP) in Bm12 cells.
- DA showed no direct binding affinity to BmHSP70-3, BmHSP75, and BmHSP83.
Conclusions:
- Destruxin A induces the expression of four heat shock proteins in Bombyx mori Bm12 cells.
- DA exhibits specific binding only to BmHSCP among the tested HSPs.
- These findings contribute to a deeper understanding of the molecular mechanisms of destruxin A's action and its insecticidal activity.
