掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier BV  

DOI： 10.1016/j.archoralbio.2022.105569

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掲載種別：研究論文（学術雑誌）   出版者・発行元：SAGE Publications  

Although vital pulp therapy should be performed by promoting the wound-healing capacity of dental pulp, existing pulp-capping materials were not developed with a focus on the pulpal repair process. In previous investigations of wound healing in dental pulp, we found that organic dentin matrix components (DMCs) were degraded by matrix metalloproteinase-20, and DMC degradation products containing protein S100A7 (S100A7) and protein S100A8 (S100A8) promoted the pulpal wound-healing process. However, the direct use of recombinant proteins as pulp-capping materials may cause clinical problems or lead to high medical costs. Thus, we hypothesized that functional peptides derived from recombinant proteins could solve the problems associated with direct use of such proteins. In this study, we identified functional peptides derived from the protein S100 family and investigated their effects on dental pulp tissue. We first performed amino acid sequence alignments of protein S100 family members from several mammalian sources, then identified candidate peptides. Next, we used a peptide array method that involved human dental pulp stem cells (hDPSCs) to evaluate the mineralization-inducing ability of each peptide. Our results supported the selection of 4 candidate functional peptides derived from proteins S100A8 and S100A9. Direct pulp-capping experiments in a rat model demonstrated that 1 S100A8-derived peptide induced greater tertiary dentin formation compared with the other peptides. To investigate the mechanism underlying this induction effect, we performed liquid chromatography–tandem mass spectrometry analysis using hDPSCs and the S100A8-derived peptide; the results suggested that this peptide promotes tertiary dentin formation by inhibiting inflammatory responses. In addition, this peptide was located in a hairpin region on the surface of S100A8 and could function by direct interaction with other molecules. In summary, this study demonstrated that a S100A8-derived functional peptide promoted wound healing in dental pulp; our findings provide insights for the development of next-generation biological vital pulp therapies.

DOI： 10.1177/00220345221135766

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その他リンク： http://journals.sagepub.com/doi/full-xml/10.1177/00220345221135766

掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

Flavobacterium johnsoniae forms a thin spreading colony on nutrient-poor agar using gliding motility. As reported in the first paper, WT cells in the colony were sparsely embedded in self-produced extracellular polymeric matrix (EPM), while sprB cells were densely packed in immature biofilm with less matrix. The colony surface is critical for antibiotic resistance and cell survival. We have now developed the Grid Stamp-Peel method whereby the colony surface is attached to a TEM grid for negative-staining microscopy. The images showed that the top of the spreading convex WT colonies was covered by EPM with few interspersed cells. Cells exposed near the colony edge made head-to-tail and/or side-to-side contact and sometimes connected via thin filaments. Nonspreading sprB and gldG and gldK colonies had a more uniform upper surface covered by different EPMs including vesicles and filaments. The EPM of sprB, gldG, and WT colonies contained filaments ~2 nm and ~5 nm in diameter; gldK colonies did not include the latter. Every cell near the edge of WT colonies had one or two dark spots, while cells inside WT colonies and cells in SprB-, GldG-, or GldK-deficient colonies did not. Together, our results suggest that the colony surface structure depends on the capability to expand biofilm.

DOI： 10.3390/ijms22136911

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Microbiology Society  

White spot syndrome virus (WSSV) is the most virulent pathogen causing high mortality and economic loss in shrimp aquaculture and various crustaceans. Therefore, the understanding of molecular mechanisms of WSSV infection is important to develop effective therapeutics to control the spread of this viral disease. In a previous study, we found that VP37 could bind with shrimp haemocytes through the interaction between its C-terminal domain and heparin-like molecules on the shrimp cells, and this interaction can also be inhibited by sulphated galactan. In this study, we present the crystal structure of C-terminal domain of VP37 from WSSV at a resolution of 2.51 Å. The crystal structure contains an eight-stranded β-barrel fold with an antiparallel arrangement and reveals a trimeric assembly. Moreover, there are two sulphate binding sites found in the position corresponding to R213 and K257. In order to determine whether these sulphate binding sites are involved in binding of VP37 to heparin, mutagenesis was performed to replace these residues with alanine (R213A and K257A), and the Surface Plasmon Resonance (SPR) system was used to study the interaction of each mutated VP37 with heparin. The results showed that mutants R213A and K257A exhibited a significant loss in heparin binding activity. These findings indicated that the sites of R213 and K257 on the C-terminal domain of envelope protein VP37 are essential for binding to sulphate molecules of heparin. This study provides further insight into the structure of C-terminal domain of VP37 and it is anticipated that the structure of VP37 might be used as a guideline for development of antivirus agent targeting on the VP37 protein.

DOI： 10.1099/jgv.0.001611

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Pharmaceutical Society of Japan  

DOI： 10.1248/cpb.c20-00011

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Pharmaceutical Society of Japan  

DOI： 10.1248/bpb.b19-00532

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

Summary

The periodontal pathogen Porphyromonas gingivalis secretes many potent virulence factors using the type IX secretion system (T9SS). T9SS cargo proteins that have been structurally determined by X‐ray crystallography are composed of a signal peptide, functional domain(s), an immunoglobulin (Ig)‐like domain and a C‐terminal domain. Role of the Ig‐like domains of cargo proteins in the T9SS has not been elucidated. Gingipain proteases, which are cargo proteins of the T9SS, were degraded when their Ig‐like domains were lacking or truncated. The degradation was dependent on the activity of a quality control factor, HtrA protease. Another T9SS cargo protein, HBP35, which has a thioredoxin domain as a functional domain, was analyzed by X‐ray crystallography, revealing that HBP35 has an Ig‐like domain after the thioredoxin domain and that the hydrophobic regions of the thioredoxin domain and the Ig‐like domain face each other. HBP35 with substitution of hydrophobic amino acids in the Ig‐like domain was degraded depending on HtrA. These results suggest that the Ig‐like domain mediates stability of the cargo proteins in the T9SS.

DOI： 10.1111/mmi.14083

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その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/mmi.14083

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