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Silkrose: A novel acidic polysaccharide from the silkmoth that can stimulate the innate immune response
Takashi Ohta1, Kie Kusano1, Atsushi Ido1
1Research Group for Reproductive Physiology, Southern Ehime Fisheries Research Center, Ehime University, 1289-1 Funakoshi, Ainan, Ehime 798-4292, Japan.
Abstract:
We have identified a novel acidic polysaccharide from silkmoth (Antheraea yamamai) pupae that activates the mammalian innate immune response. This bioactive polysaccharide was isolated using nitric oxide production in mouse RAW264 macrophages as an indicator of immunostimulatory activity. We named this polysaccharide "silkrose". It has a molecular weight of 3.15 × 10(5) and comprises nine monosaccharides. The expression profiles indicated that silkrose induced the expression of proinflammatory cytokines and interferon β that exist downstream of MyD88-dependent and MyD88-indeptendent signaling pathways. Also, the inhibition of Toll-like receptor 4 (TLR4), which exists upstream of the signaling pathways, led to the suppression of NO production by silkrose. Furthermore, this polysaccharide promoted the activation of nuclear factor kappa B in RAW264 cells, indicating that it stimulates the induction of various cytokines in macrophages through the TLR4 signaling pathway. Our results thus suggest that silkrose activates the innate immune response to various pathogenic microorganisms and viral infections.
Insights
A novel polysaccharide, silkrose, from silkmoth pupae activates the mammalian innate immune response. It stimulates cytokine production via the Toll-like receptor 4 (TLR4) pathway, offering potential against infections.
Area of Science:
- Immunology
- Biochemistry
- Natural Products
Background:
- The innate immune system provides the first line of defense against pathogens.
- Identifying novel compounds that modulate immune responses is crucial for developing new therapeutics.
Purpose of the Study:
- To isolate and characterize a novel immunostimulatory polysaccharide from silkmoth pupae.
- To elucidate the mechanism by which this polysaccharide activates innate immunity.
Main Methods:
- Isolation of an acidic polysaccharide from Antheraea yamamai pupae using nitric oxide production in RAW264 macrophages as a bioassay.
- Characterization of the polysaccharide's molecular weight and monosaccharide composition.
- Analysis of cytokine and interferon-beta expression.
- Investigation of signaling pathways, including MyD88-dependent and -independent pathways, and Toll-like receptor 4 (TLR4) involvement.
- Assessment of nuclear factor kappa B (NF-κB) activation.
Main Results:
- A novel acidic polysaccharide, named silkrose, was isolated and found to have a molecular weight of 3.15 × 10^5 Da, composed of nine monosaccharides.
- Silkrose significantly induced the expression of proinflammatory cytokines and interferon-beta.
- Immune activation was dependent on the Toll-like receptor 4 (TLR4) signaling pathway, involving both MyD88-dependent and -independent pathways.
- Silkrose promoted nuclear factor kappa B (NF-κB) activation in macrophages.
Conclusions:
- Silkrose is a potent activator of the mammalian innate immune response.
- The mechanism of action involves the TLR4 signaling pathway, leading to the induction of key immune mediators.
- Silkrose holds potential as a therapeutic agent against microbial and viral infections.
