Nitric oxide inhibits androgen receptor-mediated collagen production in human gingival fibroblasts

Expression of epithelial–mesenchymal transition-associated proteins and proliferating cell nuclear antigen in dihydropyridine-induced gingival overgrowth fibroblasts: A preliminary study

Background/purpose

The clinical features of dihydropyridine-induced gingival overgrowth (DIGO), including extracellular matrix accumulation and cell hyperplasia, are regulated by inflammatory factors (e.g., Interleukin-1β [IL-1β]) in combination with calcium channel blockers (e.g., nifedipine [Nif]). We speculated that IL-1β and Nif (IL-1β/Nif) may be the main factor modulating the proliferative potential and turnover of fibroblasts in DIGO.

Materials and methods

We cultured four DIGO fibroblast strains and analysed the possible effects of IL-1β/Nif treatments on epithelial-mesenchymal transition (EMT)-associated proteins. We developed short hairpin ribonucleic acids (shRNAs) and used them to explore the role of IL-1β/Nif in regulating proliferating cell nuclear antigen (PCNA) levels in DIGO tissues.

Results

Our results revealed that compared with control cells, DIGO cells stimulated with IL-1β/Nif had higher levels of the EMT-associated proteins Snail, Slug, and Twist. Moreover, both drugs enhanced androgen receptor (AR), Slug, and PCNA expression.

Conclusion

Taken together, our data indicate that proinflammatory cytokines in combination with calcium channel blockers can regulate the expression of EMT-associated proteins and increase the proliferative potential of DIGO fibroblasts.

The Effects of Non-Thermal Atmospheric Pressure Plasma treated Titanium Surface on Behaviors of Oral Soft Tissue Cells

Here, we investigated the possible use of the technology known as non-thermal atmospheric pressure plasma on integration and control of cytokine release of soft tissue on titanium surface. After NTAPP was applied to titanium samples, changes of surface characteristics were measured as topographical features, contact angle, surface tension, and with X-ray photoelectron spectroscopy (XPS). Protein absorption was evaluated using a bovine serum albumin absorption assay. The attachment, viability, morphology, proliferation, and cytokine release of soft tissue on titanium were assessed. No change in topographical features was observed between control and NTAPP-treated groups. However, NTAPP treatment resulted in significant lowering of the contact angle for polar and non-polar liquids and increase of surface tension. Protein absorption was significantly enhanced on the NTAPP-treated samples. Normal soft tissue attachment was improved on the NTAPP-treated groups with good viability. Cellular morphology was improved in NTAPP-treated groups whereas cellular proliferation was not enhanced. There was a significant reduction in the amounts of cytokine release for inflamed IHOK and hTERT-hNOF on the NTAPP-treated groups; except for IL-8 for IHOKs. This study demonstrates that surface functional consequences by NTAPP exposure enhanced behavior of oral soft tissue cells without topographical change.

Antibacterial activity and effect on gingival cells of microwave-pulsed non-thermal atmospheric pressure plasma in artificial saliva

Although various oral pathogens are inactivated by non-thermal atmospheric pressure plasma (NTAPP), the in vivo effects of NTAPP are poorly understood. The first aim of this study was to examine the antibacterial activity of microwave-pulsed NTAPP against Staphylococcus aureus in artificial saliva to mimic oral environmental conditions. The second aim was to determine the influence of microwave-pulsed NTAPP on human gingival fibroblasts (HGFs). The microwave-pulsed NTAPP reduced bacterial viability (as measured by colony forming units [CFU]) to a greater extent in artificial saliva than in saline. Extending the post-treatment incubation time increased bacterial inactivation in artificial saliva compared to saline. HGFs viability was unaffected by microwave-pulsed NTAPP for bacterial inactivation. Rather, HGFs proliferation increased after a 5-min microwave-pulsed NTAPP. Less tumor necrosis factor alpha was released by microwave-pulsed NTAPP-treated HGFs stimulated with lipopolysaccharide (LPS) than by untreated, LPS-stimulated HGFs; thus, plasma appeared to suppress the inflammatory response. Our study suggests that microwave-pulsed NTAPP may have stronger in vivo antibacterial activity than in vitro activity, and that microwave-pulsed NTAPP may have the additional advantage of suppressing gingival inflammatory responses.

Synthetic Fluororutaecarpine Inhibits Inflammatory Stimuli and Activates Endothelial Transient Receptor Potential Vanilloid-Type 1

The natural product, rutaecarpine (RUT), is the main effective component of Evodia rutaecarpa which is a widely used traditional Chinese medicine. It has vasodilation, anticoagulation, and anti-inflammatory activities. However, further therapeutic applications are limited by its cytotoxicity. Thus, a derivative of RUT, 10-fluoro-2-methoxyrutaecarpine (F-RUT), was designed and synthesized that showed no cytotoxicity toward RAW264.7 macrophages at 20 μM. In an anti-inflammation experiment, it inhibited the production of nitric oxide (NO) and tumor necrosis factor (TNF)-α in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages; cyclooxygenase (COX)-2 and inducible NO synthase (iNOS) induced by LPS were also downregulated. After 24 h of treatment, F-RUT significantly inhibited cell migration and invasion of ovarian A2780 cells. Furthermore, F-RUT promoted expressions of transient receptor potential vanilloid type 1 (TRPV1) and endothelial (e)NOS in human aortic endothelial cells, and predominantly reduced the inflammation in ovalbumin/alum-challenged mice. These results suggest that the novel synthetic F-RUT exerts activities against inflammation and vasodilation, while displaying less toxicity than its lead compound.

Non-thermal atmospheric pressure plasma increased mRNA expression of growth factors in human gingival fibroblasts

OBJECTIVES

The aim of this in vitro study was to investigate the effects of a non-thermal atmospheric pressure plasma jet (NTAPPJ) on the cellular activity of human gingival fibroblasts (HGF) for possible non-surgical application of it during gingival wound healing.

MATERIALS AND METHODS

HGF cells were exposed with NTAPPJ for 1, 2, and 4 min and were investigated for cellular attachment, cell viability, morphology of attached cells, proliferation rate, and messenger ribonucleic acid (mRNA) expression of various growth factors. Also, scavengers for chemicals produced by NTAPPJ were used to identify the chemical species responsible for the effects.

RESULTS

There was no significant change in the number of HGF cells attached or their proliferation following NTAPPJ exposure. Also, high cell viability resulted from exposure of all of HGF cells to NTAPPJ for 1, 2, and 4 min. However, cells were more stretched while the mRNA expressions of transforming growth factor and vascular endothelial growth factor were significantly increased following NTAPPJ exposure. Additionally, the scavenger test showed that nitric oxide is likely to be the chemical responsible for an increase of cellular activity.

CONCLUSION

The results demonstrated that the NTAPPJ increased mRNA expressions of growth factors in human gingival fibroblasts.

CLINICAL RELEVANCE

Application of NTAPPJ would be useful in gingival wound healing in clinics though additional studies confirming the effects would be needed.

NF-κB Enhances Androgen Receptor Expression through 5′-UTR Binding in Gingival Cells

Dihydropyridine-induced gingival overgrowth (DIGO) is a side effect observed in patients treated for hypertension. The disease is aggravated by inflammation. Nifedipine (Nif), a dihydropyridine, causes gingival overgrowth by increasing the expression of the androgen receptor (AR). Furthermore, the proinflammatory cytokine interleukin 1β (IL-1β) induces collagen α1(I) expression through the AR in DIGO fibroblasts. These observations prompted us to investigate whether and how nuclear factor kappa B (NF-κB) affects AR expression in DIGO. Therefore, gingival fibroblasts obtained from the tissues of patients with DIGO and healthy subjects were stimulated with IL-1β, Nif, or both. mRNA and protein expression was detected with real-time polymerase chain reaction and Western blotting. High correlation coefficients were observed for the mRNA expression of the AR, connective tissue growth factor, and collagen α1(I) induced by both drugs. Western blot analysis showed that IL-1β and Nif increased and activated NF-κB more in DIGO cells than in healthy cells. An electrophoretic mobility shift assay demonstrated that the promoter and 5′-untranslated regions (5′-UTRs) of the AR gene contains 3 binding sites for the NF-κB p65 subunit. A chromatin immunoprecipitation assay revealed that the NF-κB p65 subunit was associated with AR 5′-UTRs in gingival fibroblasts. A site-directed mutagenesis study indicated that a mutation of NF-κB binding sites reduced Nif- and IL-1β-induced AR promoter activities. Collectively, these data indicate that NF-κB is an essential transcriptional regulator of AR gene expression and thus plays a crucial role in collagen overproduction in DIGO fibroblasts.

Decreased expression of P54(nrb) /NonO correlates with collagen deposition and fibrosis in human aortic dissection

AIMS

Aortic dissection (AD) is characterized by changes in the extracellular matrix, including fibrosis with collagen production. P54(nrb) /NonO is known to be involved in collagen formation. In this study, we examined whether AD is associated with abnormal P54(nrb) /NonO expression.

METHODS AND RESULTS

Aortic specimens and serum were obtained from 10 patients with AD and 10 controls. In-vitro cultures of vascular smooth muscle cells (VSMCs) and adventitial fibroblasts (AFs) were obtained from organ donors. P54(nrb) /NonO protein and mRNA levels were determined by Western blot, immunohistochemistry and quantitative real-time reverse transcription-polymerase chain reaction (quantitative real-time RT-PCR). To evaluate collagen expression, we stained tissue sections with Masson's trichrome. Serum concentration of TNF-α was determined by enzyme-linked immunosorbent assay (ELISA). Aortic P54(nrb) /NonO protein and mRNA were decreased in AD patients, compared with controls. Decreased P54(nrb) /NonO mRNA correlated significantly with increased collagen deposition and fibrosis in AD aortas. In VSMCs and AFs from normal human aortas, P54(nrb) /NonO was expressed strongly and localized to the nucleus.

CONCLUSIONS

Patients with AD exhibited significantly decreased expression of P54(nrb) /NonO. The significant correlation between P54(nrb) /NonO and collagen may point to novel thinking about collagen metabolism research in AD aorta.

Low-cytotoxic synthetic bromorutaecarpine exhibits anti-inflammation and activation of transient receptor potential vanilloid type 1 activities

Rutaecarpine (RUT), the major bioactive ingredient isolated from the Chinese herb Evodia rutaecarpa, possesses a wide spectrum of biological activities, including anti-inflammation and preventing cardiovascular diseases. However, its high cytotoxicity hampers pharmaceutical development. We designed and synthesized a derivative of RUT, bromo-dimethoxyrutaecarpine (Br-RUT), which showed no cytotoxicity at 20 μM. Br-RUT suppressed nitric oxide (NO) production and tumor necrosis factor-α release in concentration-dependent (0~20 μM) manners in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages; protein levels of inducible NO synthase (iNOS) and cyclooxygenase-2 induced by LPS were downregulated. Br-RUT inhibited cell migration and invasion of ovarian carcinoma A2780 cells with 0~48 h of treatment. Furthermore, Br-RUT enhanced the expression of transient receptor potential vanilloid type 1 and activated endothelial NOS in human aortic endothelial cells. These results suggest that the synthetic Br-RUT possesses very low cytotoxicity but retains its activities against inflammation and vasodilation that could be beneficial for cardiovascular disease therapeutics.

A simple dot-blot-Sirius red-based assay for collagen quantification

The assessment of collagen content in tissues is important in biomedical research, since this protein is altered in numerous diseases. Hydroxyproline and Sirius red based assays are the most common methods for collagen quantification. However, these procedures have some pitfalls, such as the requirement of oxygen-free medium or expensive equipment and large sample size or being unsuitable for hydrolyzed collagen, respectively. Our objective was to develop a specific, versatile, and user-friendly quantitative method applicable to small tissue samples and extracts obtained from elastin purification, therefore, suitable for simultaneous quantification of elastin. This method is based on the binding of Sirius red to collagen present in a sample immobilized on a PVDF membrane, as in the dot-blot technique, and quantified by a scanner and image analysis software. Sample loading, Sirius red concentration, temperature and incubation time, type of standard substance, albumin interference, and quantification time are optimized. The method enabled the quantification of (1) intact collagen in several rat tissue homogenates, including small resistance-sized arteries, (2) partially hydrolyzed collagen obtained from NaOH extracts, compatible with elastin purification, and (3) for the detection of differences in collagen content between hypertensive and normotensive rats. We conclude that the developed technique can be widely used since it is versatile (quantifies intact and hydrolyzed collagen), requires small sample volumes, is user-friendly (low-cost, easy to use, minimum toxic materials, and reduced time of test), and is specific (minimal interference with serum albumin).