Differential expression of transcription factors NF-κB and STAT3 in periodontal ligament fibroblasts and gingiva of healthy and diseased individuals.

OBJECTIVE: Pathogens and host mediators can activate transcription factors in periodontal cells to bring about gene level alterations, thereby accentuating the periodontal disease process. Nuclear factor-kappa B (NF-κB) and signal transducers and activators of transcription 3 (STAT3) are two pivotal transcription factors implicated in chronic inflammatory diseases. But their importance in periodontal pathogenesis has not been investigated in detail. The aim of the present study was to evaluate the expression of activated transcription factors and their target genes in healthy and diseased periodontium. DESIGN: Primary culture of periodontal ligament fibroblasts (PDLF) were established from healthy and diseased periodontium using explant culture methods. NF-κB and STAT3 activation in these cells by Porphyromonas gingivalis LPS (lipopolysaccharide) was demonstrated using confocal microscopy and mRNA expression of target genes were evaluated by quantitative real time PCR. NF-κB and STAT3 expression in diseased and healthy gingival tissues were analyzed using immunohistochemistry. RESULTS: A basal upregulation of transcription factors and their target genes were noted in diseased PDLF compared to healthy ones. LPS challenge induced differential expression of NF-κB and STAT3 and their target genes in diseased PDLF compared to healthy ones. Immunohistochemical analysis revealed significant activation of transcription factors in diseased gingival tissues. CONCLUSION: The findings of the present study reveal the role of transcription factors NF-κB and STAT3 in periodontal pathogenesis and disease susceptibility of fibroblast subpopulations in periodontal disease could be mediated through activation of NF-κB and STAT3. Since genetic factors are nonmodifyable, transcription factors are promising targets for future host modulation therapy.

Bis(3,5-diiodo-2,4,6-trihydroxyphenyl)squaraine photodynamic therapy disrupts redox homeostasis and induce mitochondria-mediated apoptosis in human breast cancer cells.

Photodynamic therapy (PDT) is a clinically established and highly evolving treatment modality for cancer. PDT utilizes a light responsive drug called photosensitizer that selectively destroys tumor cells upon light irradiation. Squaraines are a class of dyes possessing all favorable characteristics of a photosensitizer and have been considered to be a potent candidate for next generation PDT. In this study we chose an iodo derivative of squaraine called diiodo-squaraine (bis(3, 5-diiodo-2,4,6-trihydroxyphenyl)squaraine) which has been reported for its tumor specificity but least studied for its cellular and molecular functions. Our studies revealed that the iodo derivative of squaraine possess maximum photodynamic activity in human breast cancer cells MDA- MB- 231 and had very little cytotoxicity in normal breast cells MCF-10A. We analyzed its pro and anti-apoptotic events initiated by oxidative stress exploring a proteomic approach and delineated other critical molecular pathways and key proteins involved in regulating the complex network of cellular response upon PDT. Our study showed that, diiodo- squaraines predominantly accumulate in mitochondria and induce mitochondria-mediated apoptosis. Our study also reveals the novel mechanistic role of diiodo-squaraines to induce oxidative stress there by activating both protective and death inducing pathways post PDT.

An ex vivo evaluation of the efficacy of andrographolide in modulating differential expression of transcription factors and target genes in periodontal cells and its potential role in treating periodontal diseases.

ETHANOPHARMACOLOGICAL RELEVANCE: Andrographolide is a herbal extract traditionally used in South Asian countries for treating inflammatory diseases. AIM OF THE STUDY: To evaluate the efficacy of andrographolide in management of periodontal disease which is a highly prevalent oral disease. MATERIALS AND METHODS: Periodontal ligament fibroblasts (PDLF) were cultured from healthy and diseased periodontium using explant culture methods. The safe dose of AG was determined using MTT assay. LPS (lipopolysaccharide) of the most important periodontopathogen, P gingivalis was used to activate NF-κB and STAT3 in PDLF. The efficacy of AG in inhibiting NF-κB and STAT3 was analyzed using immunofluorescence. Down regulation of expression of target genes of these transcription factors related to inflammation and bone resorption were analyzed using real time PCR. RESULTS: AG up to the concentration of 25µM was found to be safe as determined by MTT assay. Statistically significant activation of NF-κB and STAT3 in cultured PDLF was observed in diseased group compared to healthy controls before and after LPS challenge. 5µM AG pretreatment significantly inhibited activation of NF-κB and STAT3 and down regulated expression of inflammatory and bone resorptive genes in cultured PDLF. CONCLUSIONS: The findings of the present study propose the adjunctive use of a novel herbal drug andrographolide as a promising host modulation agent for periodontal therapy by inhibiting NF-κB and STAT3 activation and inhibition of inflammation and bone resorption related genes.

Enhancement in intramolecular interactions and in vitro biological activity of a tripodal tetradentate system upon complexation.

Novel biomimetic mononuclear complexes, [Fe()Cl2](+) () and [Cu()(H2O)](2+) () based on naphthalimide appended tripodal tetradentate ligand ( = 2,2',2''-(3,3',3''-(2,2',2''-nitrilotris(methylene)tris(1H-benzo[d]imidazole-2,1-diyl))tris(propane-3,1-diyl))tris(1H-benzo-[de]isoquinoline-1,3(2H)-dione)) have been synthesized and characterized by various analytical and spectral techniques. In addition, the structures of the ligand () and complex were established unambiguously through X-ray crystal structure analysis. Uniquely, the coordination with a metal ion modified the ligand scaffold to interact efficiently with ct-DNA (groove binding) as well as protein (hydrophobic and/or electrostatic interactions). We have determined the affinity of these complexes for DNA/protein and the values are found to be in the range, KDNA = 0.34-1.01 × 10(4) M(-1) and KBSA = 4.1-5.0 × 10(5) M(-1). Furthermore, the fluorescence quenching of BSA with complexes and occurs through a static mechanism and affects the conformation of BSA around the tryptophan residues. The in vitro biological studies of these systems employing HeLa cell lines indicated that both these complexes exhibited enhanced cytotoxicity (IC50 = 32 ± 0.19 and 10 ± 0.21 µM for complexes and , respectively), when compared to the ligand () (IC50 = 150 µM). Interestingly, both the complexes ( and ) were found to be non-toxic to normal H9C2 cell lines. The mechanism of in vitro biological activity of these complexes has been evaluated through a variety of techniques: acridine orange/ethidium bromide, DAPI staining studies, annexin V-FITC/PI and poly(ADP-ribose)-polymerase (PARP) cleavage, which confirmed the apoptotic mediated cell death. Our results demonstrate the importance of complexation of the naphthalimide ligand () as well as the potential of these biomimetic metal complexes as cytotoxic and anticancer agents.

Meso-tetrakis(p-sulfonatophenyl)N-confused porphyrin tetrasodium salt: a potential sensitizer for photodynamic therapy.

A water-soluble derivative of N-confused porphyrin (NCP) was synthesized, and the photodynamic therapeutic (PDT) application was investigated by photophysical and in vitro studies. High singlet oxygen quantum yield in water at longer wavelength and promising IC(50) values in a panel of cancer cell lines ensure the potential candidacy of the sensitizer as a PDT drug. Reactive oxygen species (ROS) generation on PDT in MDA-MB 231 cells and the apoptotic pathway of cell death was illustrated using different techniques.