Tyrosinase Inhibition and Kinetic Details of Puerol A Having But-2-Enolide Structure from .

Puerol A () from showed highly potent inhibition against both monophenolase (IC = 2.2 μM) and diphenolase (IC = 3.8 μM) of tyrosinase.

A vitronectin-derived peptide reverses ovariectomy-induced bone loss via regulation of osteoblast and osteoclast differentiation.

Osteoporosis affects millions of people worldwide by promoting bone resorption and impairing bone formation. Bisphosphonates, commonly used agents to treat osteoporosis, cannot reverse the substantial bone loss that has already occurred by the time of diagnosis. Moreover, their undesirable side-effects, including osteonecrosis of the jaw, have been reported.

Dentin wear after simulated toothbrushing with water, a liquid dentifrice or a standard toothpaste.

Purpose: To investigate the influence of dentifrices with and without abrasives on the wear and surface topography of human dentin following simulated toothbrushing in vitro.

Methods: 24 dentin specimens were prepared and randomly allocated to a liquid dentifrice (Garglin Gum-Guard), conventional dentifrice (333 Clinic Total Care), and control (distilled water) groups. Specimens were subjected to simulated toothbrushing of 50,000 repeated strokes under a 150 g-load.

A transcriptional roadmap to the senescence and differentiation of human oral keratinocytes.

Human epithelial cells undergo morphological and molecular changes leading to terminal differentiation and replicative senescence after a finite number of cell divisions during serial subculture. However, the target genes and their functional significance in the senescence and differentiation in normal human oral keratinocytes have been poorly defined. Here, we demonstrated normal human oral keratinocytes transcriptional signature profiling to senescence and differentiation.

Titanium surface coating with a laminin-derived functional peptide promotes bone cell adhesion.

Laminin-derived peptide coatings can enhance epithelial cell adhesion to implants, and the positive effect of these peptides on bone cell adhesion has been anticipated. The purpose of this study was to evaluate the improvement in bone cell attachment to and activity on titanium (Ti) scaffolds coated with a laminin-derived functional peptide, Ln2-P3 (the DLTIDDSYWYRI motif). Four Ti disc surfaces were prepared, and a human osteosarcoma (HOS) cell attachment test was performed to select two candidate surfaces for peptide coating.

The effect of the DLTIDDSYWYRI motif of the human laminin α2 chain on implant osseointegration.

Considerable effort has been directed towards replacing lost teeth using tissue-engineering methods such as titanium implants. A number of studies have tried to modify bioinert titanium surfaces by coating them with functionally bioactive molecules for faster and stronger osseointegration than pure titanium surfaces. Recently, peptides have been recognized as valuable scientific tools in the field of tissue-engineering.

Protein kinase Cα/β inhibitor Gö6976 promotes PC12 cell adhesion and spreading through membrane recruitment and activation of protein kinase Cδ.

Gö6976 is a nonglycosidic indolocarbazole compound widely used as a specific inhibitor of PKCα/β. In experiments probing for a role of PKCα in human laminin-2-integrin-mediated cell adhesion and spreading of PC12 cells, we observed unexpected enhancements of adhesion, spreading and stress fiber formation to 1 μM Gö6976 with concomitant increase in membrane translocation of PKCδ and autophosphorylation of focal adhesion kinase (FAK). Importantly, enhanced cellular behavior and membrane translocation of PKCδ induced by Gö6976 was retained in siRNA-transfected PC12 cells to knockdown PKCα expression.

The potential of laminin-2-biomimetic short peptide to promote cell adhesion, spreading and migration by inducing membrane recruitment and phosphorylation of PKCδ.

Laminin α2 chain plays an important role in basement membrane assembly and peripheral myelinogenesis; however, the integrin binding motif within human laminin α2 chain and the signaling pathways downstream of this ligand-receptor interaction are poorly understood. We identified a motif, RNIPPFEGCIWN (Ln2-LG3-P2), within LG3 domain of human laminin α2 chain as a major site for both α3β1 integrin and cellular activities such as cell adhesion, spreading, and migration. Binding of α3β1 integrin with Ln2-LG3-P2 induced the membrane recruitment of protein kinase Cδ (PKCδ) and stimulated its tyrosine phosphorylation.

Toll-like receptor 9 mediates oral bacteria-induced IL-8 expression in gingival epithelial cells.

Previously, we reported that various oral bacteria regulate interleukin (IL)-8 production differently in gingival epithelial cells. The aim of this study was to characterize the pattern recognition receptor(s) that mediate bacteria-induced IL-8 expression. Among ligands that mimic bacterial components, only a Toll-like receptor (TLR) 9 ligand enhanced IL-8 expression as determined by ELISA.

The potential of mouse skin-derived precursors to differentiate into mesenchymal and neural lineages and their application to osteogenic induction in vivo.

Although previous studies indicate that skin-derived precursors (SKPs) are multipotent dermal precursors that share similarities with neural crest stem cells (NCSCs), a shared ability for multilineage differentiation toward neural crest lineages between SKPs and NCSCs has not been fully demonstrated. Here, we report the derivation of SKPs from adult mouse skin and their directed multilineage differentiation toward neural crest lineages. Under controlled in vitro conditions, mouse SKPs were propagated and directed toward peripheral nervous system lineages such as peripheral neurons and Schwann cells, and mesenchymal lineages, such as osteogenic, chondrogenic, adipogenic, and smooth muscle cells.

Spontaneous tumorigenicity of primary human oral keratinocytes with human papillomavirus negativity and impaired apoptosis.

Although >60% of oral cancer cases are not related to human papillomavirus (HPV) infection, most studies of oral carcinogenesis in human cells in vitro are carried out with human oral keratinocytes immortalized by HPV DNA. To explore whether human oral keratinocytes can spontaneously transform without HPV infection, we attempted to establish spontaneously immortalized and tumorigenic-transformed human oral keratinocytes by serial subculture to the post-mitotic stage. Here we report two spontaneously transformed human oral keratinocyte lines from adult human gingival samples.

A biologically active sequence of the laminin alpha2 large globular 1 domain promotes cell adhesion through syndecan-1 by inducing phosphorylation and membrane localization of protein kinase Cdelta.

Laminin-2 promotes basement membrane assembly and peripheral myelinogenesis; however, a receptor-binding motif within laminin-2 and the downstream signaling pathways for motif-mediated cell adhesion have not been fully established. The human laminin-2 alpha2 chain cDNAs cloned from human keratinocytes and fibroblasts correspond to the laminin alpha2 chain variant sequence from the human brain. Individually expressed recombinant large globular (LG) 1 protein promotes cell adhesion and has heparin binding activities.

alpha3beta1 integrin promotes cell survival via multiple interactions between 14-3-3 isoforms and proapoptotic proteins.

Laminin-5 and alpha3beta1 integrin promote keratinocyte survival; however, the downstream signaling pathways for laminin-5/alpha3beta1 integrin-mediated cell survival had not been fully established. We report the unexpected finding of multiple interactions between 14-3-3 isoforms and proapoptotic proteins in the survival signaling pathway. Ln5-P4 motif within human laminin-5 alpha3 chain promotes cell survival and anti-apoptosis by inactivating Bad and YAP.

Plasma-treated silk fibroin nanofibers for skin regeneration.

Silk fibroin (SF) nanofibers were prepared by electrospinning and treated with plasma in the presence of oxygen or methane gas to modify their surface characteristics. The surface characteristics of the SF nanofibers after plasma treatment were examined using contact angle measurements and XPS analysis. The hydrophilicity of the electrospun SF nanofibers decreased slightly by the CH(4) plasma treatment.