Biology subjects

Sugita, T.

Publications and source records attributed to Sugita, T..

4 recordsLinked to original sources

bioRxiv2024

Acid-treated Staphylococcus aureus induces acute silkworm hemolymph melanization

The skin microbiome maintains healthy human skin, and disruption of the microbiome balance leads to inflammatory skin diseases such as folliculitis and atopic dermatitis. Staphylococcus aureus and Cutibacterium acnes are pathogenic bacteria that simultaneously inhabit the skin and cause inflammatory diseases of the skin through the activation of innate immune responses. Silkworms are useful invertebrate animal models for evaluating innate immune responses. In silkworms, phenoloxidase generates melanin as an indicator of innate immune activation upon the recognition of bacterial or fungal components. We hypothesized that S. aureus and C. acnes interact to increase the innate immunity-activating properties of S. aureus. In the present study, we showed that acidification is involved in the activation of silkworm hemolymph melanization by S. aureus. Autoclaved-killed S. aureus (S. aureus [AC]) alone does not greatly activate silkworm hemolymph melanization. On the other hand, applying S. aureus [AC] treated with C. acnes culture supernatant increased the silkworm hemolymph melanization. Adding C. acnes culture supernatant to the medium decreased the pH. S. aureus [AC] treated with propionic acid, acetic acid, or lactic acid induced higher silkworm hemolymph melanization activity than untreated S. aureus [AC]. S. aureus [AC] treated with hydrochloric acid also induced silkworm hemolymph melanization. The silkworm hemolymph melanization activity of S. aureus [AC] treated with hydrochloric acid was inhibited by protease treatment of S. aureus [AC]. These results suggest that acid treatment of S. aureus induces innate immune activation in silkworms and that S. aureus proteins are involved in the induction of innate immunity in silkworms.

microbiology↗

bioRxiv2022

Acute innate immune activation in silkworm by the human commensal bacterium Cutibacterium acnes

Cutibacterium acnes is a pathogenic bacterium that cause inflammatory diseases of the skin and intervertebral discs. The immune activation induced by C. acnes requires multiple cellular responses in the host. Silkworm, an invertebrate, generates melanin by phenoloxidase upon recognizing bacterial or fungal components. Therefore, the melanization reaction can be used as an indicator of innate immune activation. A silkworm infection model was developed for evaluating the virulence of C. acnes, but a system for evaluating the induction of innate immunity by C. acnes using melanization as an indicator has not yet been established. Here we demonstrated that C. acnes rapidly causes melanization of the silkworm hemolymph within 3 h. On the other hand, Staphylococcus aureus, a gram-positive bacterium identical to C. acnes, does not cause immediate melanization. Even injection of heat-killed C. acnes cells caused melanization of the silkworm hemolymph. DNase, RNase, and protease treatment of the heat-treated C. acnes cells did not decrease the silkworm hemolymph melanization. Treatment with peptidoglycan-degrading enzymes, such as lysostaphin and lysozyme, however, decreased the induction of melanization by the heat-treated C. acnes cells. These findings suggest that silkworm hemolymph melanization may be a useful indicator to evaluate innate immune activation by C. acnes and that C. acnes peptidoglycans are involved in the induction of innate immunity in silkworms.

microbiology↗

bioRxiv2021

Comparative analysis of Mycobacterium abscessus clinical isolate virulence using an invertebrate infection model

Mycobacterium abscessus causes chronic skin infections, lung diseases, and systemic or disseminated infections. Here we investigated whether the virulence of M. abscessus clinical isolates could be evaluated by calculating the median lethal dose (LD50) in a silkworm infection model. M. abscessus subsp. abscessus cells were injected into the silkworm hemolymph. When reared at 37{degrees}C, the silkworms died within 2 days post-infection with M. abscessus subsp. abscessus. Viable cell numbers of M. abscessus subsp. abscessus increased in the hemolymph of silkworms injected with M. abscessus subsp. abscessus. Silkworms were not killed by injections with heat-killed M. abscessus subsp. abscessus cells. The administration of clarithromycin, an antibacterial drug used to treat the infection, prolonged the survival time of silkworms injected with M. abscessus subsp. abscessus. The LD50 values of 7 clinical isolates were determined using the silkworm infection model and differed by up to 9-fold. The Mb-17 isolate, which was identified as a pathogenic strain in the silkworm infection model, induced more detachment of human THP-1-derived macrophages during infection than the Mb-10 isolate. These findings suggest that the silkworm M. abscessus infection model with can be used to quantitatively evaluate the virulence of M. abscessus clinical isolates in a short time period.

microbiology↗

bioRxiv2020

Comparative mapping of crawling-cell morphodynamics in deep learning-based feature space

Navigation of fast migrating cells such as amoeba Dictyostelium and immune cells are tightly associated with their morphologies that range from steady polarized forms that support high directionality to those more complex and variable when making frequent turns. Model simulations are essential for quantitative understanding of these features and their origins, however systematic comparisons with real data are underdeveloped. Here, by employing deep-learning-based feature extraction combined with phase-field modeling framework, we show that a low dimensional feature space for 2D migrating cell morphologies obtained from the shape stereotype of keratocytes, Dictyostelium and neutrophils can be fully mapped by interlinked signaling network of cell-polarization and protrusion dynamics. Our analysis links the data-driven shape analysis to the underlying causalities by identifying key parameters critical for migratory morphologies both normal and aberrant under genetic and pharmacological perturbations. The results underscore the importance of deciphering self-organizing states and their interplay when characterizing morphological phenotypes.

cell biology↗