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To find an inhibitor of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) that rapidly metabolises Prostaglandin E2 (PGE2) as a mediator of wound healing, we examined seven flavonoids for this role. 7,3′,4′-Trimethoxyflavone (TMF) had the lowest IC50 value of 0.34 µM for 15-PGDH inhibition but >400 µM for cytotoxicity, indicating a high therapeutic index. TMF elevated PGE2 levels in a concentration-dependent manner in both A549 lung cancer and HaCaT cells. It also significantly increased mRNA expression of multidrug resistance-associated protein 4 (MRP4) and of prostaglandin transporter (PGT) slightly in HaCaT cells. In addition, TMF facilitated in vitro wound healing in a HaCaT scratch model, which was completely inhibited by adding both 15-PGDH and NAD+ as cofactor, confirming the involvement of PGE2 in its wound healing effect. TMF with a high therapeutic index can facilitate wound healing through PGE2 elevation by 15-PGDH inhibition.

Heat shock protein-27 (HSP27) is a member of the small HSP family which has been linked to the nuclear factor-kappa B (NF-κB) signaling pathway regulating inflammatory responses. Clinical reports have suggested that low-level light therapy/laser irradiation (LLLT) could be an effective alternative treatment to relieve inflammation during bacterial infection associated with periodontal disease. However, it remains unclear how light irradiation can modulate the NF-κB signaling pathway. We examined whether or not 635 nm irradiation could lead to a modulation of the NF-kB signaling pathway in HSP27-silenced cells and analyzed the functional cross-talk between these factors in NF-κB activation. The results showed that 635 nm irradiation led to a decrease in the HSP27 phosphorylation, reactive oxygen species (ROS) generation, I-κB kinase (IKK)/inhibitor of κB (IκB)/NF-κB phosphorylation, NF-κB p65 translocation and a subsequent decrease in the COX-1/2 expression and prostaglandin (PGE(2) ) release in lipopolysaccharide(LPS)-induced human gingival fibroblast cells (hGFs). However, in HSP27-silenced hGFs, no obvious changes were observed in ROS generation, IKK/IκB/NF-κB phosphorylation, NF-κB p65 translocation, nor in COX-1/2 expression, or PGE(2) release. This could be a mechanism by which 635 nm irradiation modulates LPS-induced NF-κB signaling pathway via HSP27 in inflammation. Thus, HSP27 may play a role in regulating the anti-inflammatory response of LLLT.

The aim of this study was to examine the reactive oxygen species (ROS) that are dissipated by 635 nm irradiation, and the effect of 635 nm irradiation on ROS scavenging system.Intracellular ROS are produced in the form of superoxide anion by either nicotinamide adenine dinucleotide phosphate (NADPH) oxidase or xanthine oxidase in response to a number of stimuli. Low-level light irradiation decreases the intracellular ROS level and has been used in clinical situations for reducing the level of oxidative stress.Human epithelial cells were exposed to exogenous and endogenous oxidizing agents that promote the generation of harmful ROS. These were then irradiated with 635 nm LED light, 5 mW/cm(2) for 1 h, 18 J/cm(2) or by 470 nm LED light, also 5 mW/cm(2) for 1 h, 18 J/cm(2) on a 9 cm cell culture dish. After irradiation, the MTT reduction method and malondialdehyde (MDA) colorimetric assay were performed in xanthine/xanthine oxidase (XXO)- or hydrogen peroxide (H(2)O(2))-treated HaCaT cells. The superoxide anion was detected by an electron spin resonance (ESR) spectrometer using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the spin trap and H(2)O(2) was assayed by flow cytometry using 2',7'-dichlorodihydrofluorescein diacetate (H(2)DCF-DA).Irradiation at 635 nm enhanced cell viability in the XXO-treated HaCaT cells. Also, irradiation had a much lesser effect on cell viability in the HaCaT cells treated with exogenous H(2)O(2) as compared with that in cells treated with N-acetyl-L-cysteine. The level of the superoxide anion increased in response to XXO treatment, and then decreased after 635 nm irradiation. Irradiation with 635 nm led to a decrease in superoxide anion and lipid peroxidation levels in the presence or absence of diethyldithiocarbamate.These results highlight the potential role of 635 nm irradiation in protection against oxidative stress by scavenging superoxide anions. Also, a pathway that is independent of the activities of intracellular enzymatic ROS scavengers, such as superoxide dismutase, glutathione peroxidase and catalase might be involved in its mechanism of action.

C16 saturated fatty acid (Palmitic acid) is one of the most common dietary fatty acids which played an important role in the cellular biological functions. Palmitic acid (PA) was tested for potential inhibition of DNA topoisomerase I (topo I) and it exhibited inhibitory activity in the nanomolar range. Treatment of lung adenocarcinoma cell line A549 with PA resulted in a decrease in cell viability in a concentration-dependent manner, and PA showed cytotoxicity with an IC50 value of 150 μM. DNA fragmentation assay and caspase activity indicated that PA does not induce apoptotic cell death in A549 cells. Finally, we found that PA was able to cause an increase in autophagic flux in a time-dependent manner, evidenced by the accumulation of LC3 through monodansylcadaverine (MDC) staining. More importantly, inhibition of autophagy by blocking autophagosome formation via the inhibition of type III Phosphatidylinositol 3-kinases (PI-3K), by 3-Methyladenine (3-MA) was able to effectively suppress PA-induced autophagy. We showed that inhibition of autophagy sensitized the cells signal to PA-induced apoptosis, suggesting the pro-survival function of autophagy induced by PA. Taken together, results from this study reveal that PA as a topo I inhibitor induced autophagic cell death in A549 cells.

Novel thiazolidinedione analogues as 15-hydroxyprostaglandin dehydrogenase (15-PGDH) inhibitors were synthesized. Compounds 2, 3, and 4 exhibited IC(50) of 25, 8, and 19 nM, respectively. They also significantly increased levels of PGE(2) in A549 cells. To assess the influence of 15-PGDH inhibitor on cochlear blood flow (CBF), 2 was applied intravenously to guinea pigs. It increased their CBFs. Scratch wounds were also analyzed in confluent monolayers of HaCaT cells. Cells exposed to 4 showed significantly improved wound healing with respect to a control.

Background Prostaglandins (PGs) have short existence in vivo because they are rapidly metabolized by NAD+-dependent 15-hydroxyprostaglandin dehydrogenase (15-PGDH) to 15-ketoprostaglandins. Inhibition of 15-PGDH causes elevated level of PGE2 in cellular system. It will be valuable for the therapeutic management of diseases requiring elevated PGE2 levels, like wound healing. Objective Ninety-eight plant samples were screened for the discovery of potent 15-PGDH inhibitor. Among them, top five plant extracts as potent 15-PGDH inhibitor were chosen to determine PGE2 release from HaCaT (Keratinocyte cell line) cell line. Finally, top 15-PGDH inhibitor was selected to evaluate in vitro wound healing effect on HaCaT scratch model. Method The inhibitory activity for 15-PGDH inhibitors was evaluated using fluorescence spectrophotometer by measuring the formation of NADH at 468 nm following excitation at 340 nm. Cell viability assay and PGE2 release was evaluated in HaCaT cell line after treatment of 15-PGDH inhibitors. Scratches were made using sterile 200 μL on HaCaT cell and wound-healing effect was evaluated after treatment of 15-PGDH inhibitor. Results 15-PGDH inhibitors elevated PGE2 levels in concentration-dependent manner. Ethanol extract of Artocarpus heterophyllus (EEAH), the most potent 15-PGDH inhibitor (IC50 = 0.62 µg/mL) with least cytotoxicity (IC50 = 670 µg/ml), elevated both intracellular and extracellular PGE2 levels. EEAH facilitated in-vitro wound healing in a HaCaT (Keratinocyte cell line) scratch model. Conclusion EEAH might apply to treat dermal wounds by elevating PGE2 levels via COX-1 induction and 15-PGDH inhibition. Summary Biological inactivation of 15-PGDH causes elevated level of PGE2 which will be useful for the management of disease that requires elevated level of PGE2. Abbreviations used: 15-PGDH: 15-hydroxyprostaglandin dehydrogenase, COX: Cyclooxygenase, DTT: Dithiothreitol, DMEM: Dulbecco's modified Eagle's media, EEAH: Ethanol extract of Artocarpus heterophyllus, MRP4: Multidrug resistance 4, PGs: Prostaglandins, PGT: Prostaglandin transporter, SDS: Sodium dodecylsulfate.

Hyperglycemia occurs in patients with poorly controlled diabetes mellitus and contributes to bone resorption and increased susceptibility to bacterial infections. Hyperglycemia can incite low-grade inflammation that can contribute to the resorption of bone, especially the periodontal bone. The increased susceptibility to periodontal infections can contribute to bone resorption through the activation of osteoclasts. In this study, the osteoblastic, clonal cell line, MC3T3-E1, was used in an in vitro model of hyperglycemia and lipopolysaccharide-induced reactive oxygen species generation to determine the potential anti-inflammatory effect of 635 nm light-emitting diode (LED) irradiation or whether 635 nm LED irradiation can be a potential anti-inflammatory treatment. LED irradiation of MC3T3-E1 cells stimulated with lipopolysaccharide in a high glucose-containing medium decreased the level of cyclooxygenase gene and protein expression and reduced the level of prostaglandin E2 expression by decreasing the amount of reactive oxygen species generation. LED irradiation also inhibited the osteoclastogenesis in MC3T3-E1 cells by regulating the receptor activator of nuclear factor kappa-B ligand and osteoprotegerin. These findings reveal the mechanisms which are important in the pathogenesis of diabetic periodontitis and highlight the beneficial effects of 635 nm LED irradiation in reducing the adverse effects of diabetic periodontitis.