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Immunological function of Bombyx Toll9-2 in the silkworm (Bombyx mori) larval midgut: Activation by Escherichia coli/lipopolysaccharide and regulation of growth.
- Source :
-
Archives of insect biochemistry and physiology [Arch Insect Biochem Physiol] 2024 Aug; Vol. 116 (4), pp. e22130. - Publication Year :
- 2024
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Abstract
- Toll receptors are important regulators of insects' innate immune system which, upon binding of pathogen molecules, activate a conserved signal transduction cascade known as the Toll pathway. RNA interference (RNAi) is a powerful tool to study the function of genes via reverse genetics. However, due to the reported refractory of RNAi efficiency in lepidopteran insects, successful reports of silencing of Toll receptors in the silkworm Bombyx mori have not been reported yet. In this study, a Toll receptor of the silkworm Bombyx Toll9-2 (BmToll9-2) was cloned and its expression and function were analyzed. The results showed that BmToll9-2 contains an ectodomain (ECD) with a signal peptide and nine leucine-rich repeats, a transmembrane helix, and a cytoplasmic region with a Toll/interleukin-1 domain. Phylogenetic analysis indicates that BmToll9-2 clusters with other insect Toll9 receptors and mammalian Toll-like receptor 4. Oral infection of exogenous pathogens showed that the Gram-negative bacterium Escherichia coli and its main cell wall component lipopolysaccharide (LPS), as well as the Gram-positive bacterium Staphylococcus aureus and its main cell wall component peptidoglycan, significantly induce BmToll9-2 expression in vivo. LPS also induced the expression of BmToll9-2 in BmN4 cells in vitro. These observations indicate its role as a sensor in the innate immunity to exogenous pathogens and as a pathogen-associated receptor that is responsive to LPS. RNAi of BmToll9-2 was effective in the midgut and epidermis. RNAi-mediated knock-down of BmToll9-2 reduced the weight and growth of the silkworm. Bacterial challenge following RNAi upregulated the expression of BmToll9-2 and rescued the weight differences of the silkworm, which may be related to its participation in the immune response and the regulation of the microbiota in the midgut lumen of the silkworm larvae.<br /> (© 2024 Wiley Periodicals LLC.)
- Subjects :
- Animals
Toll-Like Receptors metabolism
Toll-Like Receptors genetics
Immunity, Innate
Staphylococcus aureus
Gastrointestinal Tract immunology
Gastrointestinal Tract microbiology
Gastrointestinal Tract metabolism
Amino Acid Sequence
RNA Interference
Bombyx immunology
Bombyx genetics
Bombyx growth & development
Bombyx microbiology
Bombyx metabolism
Larva immunology
Larva growth & development
Larva microbiology
Larva genetics
Larva metabolism
Escherichia coli
Insect Proteins genetics
Insect Proteins metabolism
Phylogeny
Lipopolysaccharides pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 1520-6327
- Volume :
- 116
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Archives of insect biochemistry and physiology
- Publication Type :
- Academic Journal
- Accession number :
- 39118437
- Full Text :
- https://doi.org/10.1002/arch.22130