Project description:The goal of this study was to compare the gene expression profiles of chronically inflamed human peri-implant and chronically inflamed human periodontal tissues in order to elucidate potential changes at the molecular level. Cells out of the pocket depth of the inflamed peri-implant and periodontal ligament as well as from the middle third of healthy periodontal ligament were applied. Genome-wide gene expression was compared with the help of microarray analysis, and the data were validated by real-time RT-PCR. The expression rates of 14,239 genes were investigated and 2,079 of them were found differentially expressed by at least two-fold; the expression rates of 1,093 genes were significantly up-regulated and the expression rates of 986 genes were significantly down-regulated in inflamed peri-implant cells compared to inflamed periodontal cells. We focused on genes coding for extracellular matrix components and those that degrade them. Only genes of non-fibril-forming collagens (types IV, VI, VII, and XVII) were increased in inflamed peri-implant tissue, whereas only the genes of two fibril-forming collagens (types III and XVII) were decreased, suggesting that peri-implant tissue re-models faster than periodontal tissue. Furthermore, cathepsin D and cathepsin S might participate to a greater extent in connective tissue destruction of peri-implant tissue. The present investigation demonstrated that, despite their clinical similarities, periimplantitis and periodontitis are two different diseases at the genetic level. Keywords: inflammation, peri-implant, periodontal ligament cells The peri-implant tissue was scraped of the implant and the periodontal tissue was scraped off the roots of the teeth. Both tissue probes were treated with the RNeasy mini Kit (Qiagen, Hilden, Germany) to isolate total RNA from chronically inflamed peri-implant and chronically inflamed PDL cells, according to the manufacturer’s instructions. Healthy PDL cells were taken from the middle third of the root clearly avoiding sampling the gingiva. The chronically inflamed peri-implant and periodontal cells were taken directly out of the depth of the pocket again avoiding the ingrown gingiva. Quality control and quantitation of total RNA samples were determined prior to the microarray experiments (Agilent 2100 Bioanalyzer, Agilent Technologies, Palo Alto, CA, USA). Equal amounts of total RNA were pooled into an inflamed peri-implant and an inflamed and healthy periodontal cell pool. To monitor the relative abundance of mRNA for full-length human genes, the Affymetrix GeneChip HG_U133A was used, representing 22,283 probe sets (14,239 unique human genes). Labelled cRNA, fragmented to an average size of 100–150 bases, was hybridized to the GeneChips. For each pool of cRNA, two GeneChips were hybridized. Chronically inflamed peri-implant as well as healthy and chronically inflamed periodontal tissue was collected from 48 patients at the Dental Medical School of the University of Goettingen (21 men, 27 women, aged between 18 and 72 years) from March 2005 to August 2006, as already described by Gersdorff et al. (2007). The peri-implant tissue probes were taken from endosteal implants (Astra Tech®, ITI Bonefit®, or Brånemark®) with chronic peri-implant lesions (Schwarz et al. 2007). The periodontal tissue probes were taken from teeth, either extracted for orthodontic reasons or due to carious lesions (healthy periodontium) or from teeth with generalized chronic periodontitis (Armitage 2004). Teeth with healthy PDL had no clinical signs of inflammation (no bleeding on probing), exhibited a probing depth of ?3,5 mm and had no radiographic detectable bone loss. In contrast, implants and teeth with generalized chronic inflammation exhibited obvious clinical signals of inflammation (bleeding on probing), exhibited a probing depth of >4 mm and had radiographic evidence of bone loss (1 to 7 mm). A detailed anamnesis of each patient was explored. All patients were without a medical history, i.e. heart diseases or diabetes, and were not on medication. In addition, the tissue samples used in our study were only taken from non-smokers. The explanted implants and extracted teeth were immediately frozen and stored at -80 °C. All patients who participated in the study were informed about the nature and aim of this project and gave their written informed consent. The study was approved according to the regulations of the Ethics Committee of the Medical Faculty of the University of Goettingen.

Project description:Background & Aims. Resection of hepatocellular carcinoma (HCC) tumors by partial hepatectomy (PHx) is associated with promoting hepatocarcinogenesis. We have previously reported that PHx promotes hepatocarcinogenesis in the Mdr2-knockout (Mdr2-KO) mouse, a model for inflammation-mediated HCC. Now, we explored the molecular mechanisms underlying the tumor-promoting effect of PHx in these mice. Methods. Using microarrays-based techniques, we compared genomic and transcriptomic profiles of HCC tumors developing in the Mdr2-KO mice either spontaneously or following PHx. Results. PHx accelerated HCC development in these mice by four months. PHx-induced tumors had only amplifications affecting multiple chromosomes and locating mainly near the acrocentric centromeres of murine chromosomes. Four different chromosomal regions were amplified each in at least three tumors. All tumors of untreated mice had chromosomal aberrations, including both deletions and amplifications. Comparison of gene expression profiles revealed a significantly enriched expression of oncogenes, chromosomal instability markers and E2F1 targets in the post-PHx compared to spontaneous tumors. Both tumor groups shared the same frequent amplification at chromosome 18. Here, we demonstrated that one of the regulatory genes encoded by this amplified region, Crem, was over-expressed in the nuclei of murine and human HCC cells in vivo, and that it stimulated proliferation of human HCC cells in vitro. Conclusions: PHx of a chronically inflamed liver directed tumor development to a discrete pathway characterized by amplification of specific chromosomal regions and expression of specific tumor-promoting genes. Crem is a new candidate HCC oncogene frequently amplified in this model and frequently over-expressed in human HCC. To explore the mechanisms of the accelerated HCC development by PHx, we compared liver tumors and their matched non-tumor liver tissues between 9-month-old hepatectomized and 13-14-month-old untreated Mdr2-KO mice.

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Impaired estrogen signaling underlies regulatory T cell loss-of-function in the chronically-inflamed intestine

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