Cytotoxic effect of interleukin-8 in retinal ganglion cells and its possible mechanisms

AIM: To investigate the effect of interleukin-8 (IL-8) on neural retinal ganglion cells (RGCs) and whether it can be alleviated by G31P. METHODS: RGC-5 cells were exposed to IL-8 with or without its specific receptor antagonist G31P for 24h, and the cell viability was assessed by Cell Counting Kit 8 (CCK-8). Apoptosis was measured by examining nuclear morphology and quantifying with flow cytometry. Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and Western blot were used to investigate the expression of apoptosis-related genes. RESULTS: CCK-8 assay showed that IL-8 significantly inhibits the viability of RGC-5 cells in a dose-dependent manner. Cell apoptosis assays exhibited higher apoptotic rate in IL-8 treatment group compared to control group. We further found that IL-8 could promote Bax and caspase-3 expressions, but decrease the level of Bcl-2 in the aspect of mRNA and protein. However, pre-treatment with G31P partly attenuated these effects in RGC-5 cells (P<0.05). CONCLUSION: These results indicate that anti-proliferation effects of IL-8 through induction of cell apoptosis regulated by Bcl-2, Bax and caspase-3 expressions, can be ameliorated by G31P

Preventive effects of the novel antimicrobial peptide Nal-P-113 in a rat Periodontitis model by limiting the growth of Porphyromonas gingivalis and modulating IL-1β and TNF-α production

Abstract Background P-113 (AKRHHGYKRKFH-NH2) is a 12-amino-acid histidine-rich peptide derived from histatin 5 that is highly degradable in high salt concentrations and biological fluids such as serum, plasma and saliva. Nal-P-113, a novel antimicrobial peptide whose histidine residues are replaced by the bulky amino acids β-naphthylalanine, causes the antimicrobial peptide to retain its bactericidal activity even in physiological environments. This study evaluated the effect of the novel antimicrobial peptide Nal-P-113 in a rat periodontitis model and the mechanisms of action of Nal-P-113 for suppressing periodontitis. Methods Periodontitis was induced in mandibular first molars in rats receiving a ligature and infected with Porphyromonas gingivalis. Animals were randomly divided into six groups: a, P. gingivalis W83 alone; b, P. gingivalis W83 with 6.25 μg/mL of Nal-P-113; c, P. gingivalis W83 with 25 μg/mL of Nal-P-113; d, P. gingivalis W83 with 100 μg/mL of Nal-P-113; e, P. gingivalis W83 with 400 μg/mL of Nal-P-113; and f, control without P. gingivalis W83 or Nal-P-113. Morphometric analysis was used to evaluate alveolar bone loss. Microbiological assessment of the presence of Porphyromonas gingivalis and total bacteria was performed using absolute quantitative real-time PCR and scanning electron microscopy. Gingival tissue was collected for western blot and immunohistochemical assays of IL-1β and TNF-α levels. Results Alveolar bone loss was inhibited by 100 μg/mL or 400 μg/mL of Nal-P-113 compared to the control group (P < 0.05). Lower amounts of P. gingivalis and total bacteria were found in groups d and e compared with group a (P < 0.05). A decrease in the levels of IL-1β and TNF-α was detected in group d and group e compared to the control group (P < 0.05). The amount of P. gingivalis was positively correlated with IL-1β and TNF-α expression in periodontal tissue (P < 0.05). Conclusions Nal-P-113 exhibited protective effects on Porphyromonas gingivalis-induced periodontitis in rats by limiting the amount of bacteria and modulating IL-1β and TNF-α production. The use of Nal-P-113 in vivo might serve as a beneficial preventive or therapeutic approach for periodontitis.https://deepblue.lib.umich.edu/bitstream/2027.42/138096/1/12906_2017_Article_1931.pd

Impact Factor: outdated artefact or stepping-stone to journal certification?

A review of Garfield's journal impact factor and its specific implementation as the Thomson Reuters Impact Factor reveals several weaknesses in this commonly-used indicator of journal standing. Key limitations include the mismatch between citing and cited documents, the deceptive display of three decimals that belies the real precision, and the absence of confidence intervals. These are minor issues that are easily amended and should be corrected, but more substantive improvements are needed. There are indications that the scientific community seeks and needs better certification of journal procedures to improve the quality of published science. Comprehensive certification of editorial and review procedures could help ensure adequate procedures to detect duplicate and fraudulent submissions.Comment: 25 pages, 12 figures, 6 table

Object Segmentation from Motion Discontinuities and Temporal Occlusions–A Biologically Inspired Model

BACKGROUND: Optic flow is an important cue for object detection. Humans are able to perceive objects in a scene using only kinetic boundaries, and can perform the task even when other shape cues are not provided. These kinetic boundaries are characterized by the presence of motion discontinuities in a local neighbourhood. In addition, temporal occlusions appear along the boundaries as the object in front covers the background and the objects that are spatially behind it. METHODOLOGY/PRINCIPAL FINDINGS: From a technical point of view, the detection of motion boundaries for segmentation based on optic flow is a difficult task. This is due to the problem that flow detected along such boundaries is generally not reliable. We propose a model derived from mechanisms found in visual areas V1, MT, and MSTl of human and primate cortex that achieves robust detection along motion boundaries. It includes two separate mechanisms for both the detection of motion discontinuities and of occlusion regions based on how neurons respond to spatial and temporal contrast, respectively. The mechanisms are embedded in a biologically inspired architecture that integrates information of different model components of the visual processing due to feedback connections. In particular, mutual interactions between the detection of motion discontinuities and temporal occlusions allow a considerable improvement of the kinetic boundary detection. CONCLUSIONS/SIGNIFICANCE: A new model is proposed that uses optic flow cues to detect motion discontinuities and object occlusion. We suggest that by combining these results for motion discontinuities and object occlusion, object segmentation within the model can be improved. This idea could also be applied in other models for object segmentation. In addition, we discuss how this model is related to neurophysiological findings. The model was successfully tested both with artificial and real sequences including self and object motion

Additional file 1: Table S1. of Molecular pathways underlying inhibitory effect of antimicrobial peptide Nal-P-113 on bacteria biofilms formation of Porphyromonas gingivalis W83 by DNA microarray

List of primers used for qPCR experiments. Table S2. Up-regulated gene list in Nal-P-113 treated P.gingivalis W83 (hypothetical protein excluded). Table S3. Down-regulated gene list in Nal-P-113 treated P.gingivalis W83 (hypothetical protein excluded). (DOCX 46 kb