No description available.

Lipopolysaccharide (LPS)-binding protein (LBP) functions as a crucial molecule in innate immune responses to bacterial challenge. Our recent study shows the expression of LBP in human gingiva and its significant association with periodontal condition. Porphyromonas gingivalis is a keystone periodontopathogen with its LPS as a major virulence factor strongly involved in periodontal pathogenesis. Recent study has discovered that P. gingivalis LPS displays a significant lipid A structural heterogeneity. The present study investigated i) the expression profile of LBP in human oral keratinocytes (HOKs) stimulated by P. gingivalis LPS with penta-acylated (LPS1690) and tetra- (LPS1435/1449) lipid A structures as well as E. coli LPS; ii) the involvement of toll-like receptors (TLRs) and downstream signaling mechanisms in LBP expression; and iii) the effects of LBP and its crosstalk with the two isoforms of P. gingivalis LPS on the expression of cytokines and human β-defensins (hBD-2) in HOKs. The expression of LBP mRNA and peptide was significantly up-regulated by P. gingivalis LPS1690 and E. coli LPS, while not by P. gingivalis LPS1435/1449. P. gingivalis LPS1690-induced LBP expression was through both TLR2 and TLR4, and the relevant down-stream signaling mechanisms were then further investigated. Western blot results showed that P. gingivalis LPS1690 activated the phosphorylation of IκBα, p65, p38 MAPK and SAPK/JNK, whereas E. coli LPS phosphorylated IκBα, p38 MAPK and SAPK/JNK. A nuclear translocation of NF-κB transcription factor was confirmed upon stimulation by both forms of LPS. Further blocking assay revealed that P. gingivalis LPS1690 induction of LBP was through NF-κB and p38 MPAK pathways, while E. coli LPS induction of LBP was mediated by NF-κB, p38 MPAK and JNK pathways. The effects of LBP and its crosstalk with P. gingivalis LPS1690 or LPS1435/1449 on the expression of cytokines and hBD-2 were further investigated. Interestingly, recombinant human LBP (rhLBP) per se could significantly up-regulate the expression of IL-6, IL-8 and TNF-α, while down-regulate hBD-2 expression. P. gingivalis LPS1690 or LPS1435/1449 modulated to different extents the rhLBP-induced cytokine expression. Notably, P. gingivalis LPS1690 significantly down-regulated rhLBP-induced IL-8 expression; whereas, P. gingivalis LPS1435/1449 down-regulated IL-8 expression more intensively (around 80% vs. 40% reduction). The key mediators of TLRs and their adaptors like CD180 and MD-1 were significantly down-regulated by rhLBP (fold changes: -2.44 and -9.62, respectively). Both CD180 and MD-1 mRNAs were up-regulated by P. gingivalis LPS1435/1449 (7.11 and 4.05 folds, respectively); while these two genes were reversely modulated by P. gingivalis LPS1690 (20.86 and -6.93 folds, respectively). The present study demonstrates that P. gingivalis LPS with a lipid A structural heterogeneity differentially modulates LBP expression in HOKs. P. gingivalis LPS1690 promotes LBP expression in HOKs through TLR2 and TLR4 as well as NF-κB and p38 MAPK pathways in a way different from E. coli LPS. rhLBP per se significantly up-regulates the expression of IL-6, IL-8 and TNF-α, while down-regulates hBD-2 expression. P. gingivalis LPS with different lipid A structures down-regulates to different extents the rhLBP-induced expression of cytokines in HOKs, likely through fine-tuning of the CD180-MD1 complex and the relevant TLRs. / published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

No description available.

Thesis (Ph.D.) -- University of Adelaide, Dept. of Biochemistry, 1984.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 103-123).

published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

Thesis (Ph. D.)--Rutgers University, 2007. / Pages missing. "Graduate Program in Toxicology."

Thesis (Ph. D.)--Case Western Reserve University, 2008. / [School of Medicine] Department of Pharmacology. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 138-159). Available also in a digital version from Dissertation Abstracts.

Yes / Genetic approaches that allow lineage tracing are essential to our future understanding of melanocytes and melanoma. To date, the approaches used to label melanocytes in mice have relied on random integration of transgenes driven by the promoters of the Tyrosinase and Dopachrome tautomerase genes, knock-in to the Dopachrome tautomerase locus or knock-in to the Mlana locus in a bacterial artificial chromosome. These strategies result in expression in other tissues such as telencephalon and other cell types such as nerves. Here we used homologous recombination in mouse embryonic stem cells to generate a targeted multicistronic allele of the Pmel locus that drives melanocyte-specific expression of CreERT2, nuclear localised H2B-Cerulean and membrane localised marcks-mKate2 allowing live imaging of melanocytes and activation of other conditional alleles. We combined this allele with R26R-EYFP mice allowing induction of EYFP expression on administration of tamoxifen or its metabolite 4-OHT. The fluorescent proteins H2B-Cerulean and marcks-mKate2 label the cell nucleus and plasma membrane respectively allowing live imaging and FACS isolation of melanoblasts and melanocytes as well as serving to provide an internal control allowing estimation of recombination efficiency after administration of tamoxifen. We demonstrate the utility of the transgene in embryonic and adult tissues. / Cancer Research UK. Grant Number: A15673. Medical Research Council. Grant Number: MC_PC_U127527200. National Centre for the Replacement Refinement and Reduction of Animals in Research. Grant Number: NC/K001612/1. North West Cancer Research Fund. Grant Number: CR1132. Medical Research Scotland. Grant Number: 436FRG