Gene set enrichment analysis in closed pyometra detected by IPA analysis.

<p>Gene set enrichment analysis in closed pyometra detected by IPA analysis.</p

Molecular Expression Profile Reveals Potential Biomarkers and Therapeutic Targets in Canine Endometrial Lesions

<div><p>Cystic endometrial hyperplasia (CEH), mucometra, and pyometra are common uterine diseases in intact dogs, with pyometra being a life threatening disease. This study aimed to determine the gene expression profile of these lesions and potential biomarkers for closed-cervix pyometra, the most severe condition. Total RNA was extracted from 69 fresh endometrium samples collected from 21 healthy female dogs during diestrus, 16 CEH, 15 mucometra and 17 pyometra (eight open and nine closed-cervixes). Global gene expression was detected using the Affymetrix Canine Gene 1.0 ST Array. Unsupervised analysis revealed two clusters, one mainly composed of diestrus and CEH samples and the other by 12/15 mucometra and all pyometra samples. When comparing pyometra with other groups, 189 differentially expressed genes were detected. <i>SLPI</i>, <i>PTGS2/COX2</i>, <i>MMP1</i>, <i>S100A8</i>, <i>S100A9</i> and <i>IL8</i> were among the top up-regulated genes detected in pyometra, further confirmed by external expression data. Notably, a particular molecular profile in pyometra from animals previously treated with exogenous progesterone compounds was observed in comparison with pyometra from untreated dogs as well as with other groups irrespective of exogenous hormone treatment status. In addition to <i>S100A8</i> and <i>S100A9</i> genes, overexpression of the inflammatory cytokines <i>IL1B</i>, <i>TNF</i> and <i>IL6</i> as well as <i>LTF</i> were detected in the pyometra from treated animals. Interestingly, closed pyometra was more frequently detected in treated dogs (64% <i>versus</i> 33%), with <i>IL1B</i>, <i>TNF</i>, <i>LBP</i> and <i>CXCL10</i> among the most relevant overexpressed genes. This molecular signature associated with potential biomarkers and therapeutic targets, such as <i>CXCL10</i> and <i>COX2</i>, should guide future clinical studies. Based on the gene expression profile we suggested that pyometra from progesterone treated dogs is a distinct molecular entity.</p></div

Protein-protein interaction (PPI) networks in closed and open pyometra.

<p>PPI networks based on altered genes exclusively detected in closed pyometra and open pyometra and their interactive partners built and visualized with Navigator v.2.3. Potential candidates for biomarkers (B blue circles) and targets for therapy (Drugs, D orange circles) in closed pyometra and open pyometra are highlighted. Triangles represent the genes with altered expression in each group and are color-coded according to Gene Ontology (GO). Upright and inverted triangles indicate overexpressed and underexpressed genes, respectively.</p

IPA network analysis.

<p>(A-D) Top networks identified with IPA software for differentially expressed genes in different group’s comparisons: A-B: Pyometra compared with diestrus, CEH and mucometra. A: Family members of the MMP and <i>S100</i> genes were detected as central nodes in pyometra and connected with pro-inflammatory cytokines. The <i>SLP1</i> gene (highest fold change in pyometra) is also depicted. B: Multiple interactions between the <i>CXCL8/IL8</i>, a pro-inflammatory gene, and other genes are shown, including the <i>PTGS2/COX2</i> gene. C-D: Pyometra of animals previously treated with progesterone compounds compared to pyometra of untreated dogs. C: The proinflammatory cytokine TNF was detected as central with multiple connections with different genes. D: <i>E2F1</i> (overexpression) and <i>VEGF</i> (underexpression) products in the treated group. The lines between genes represent known interactions, with solid lines and dashed lines representing direct and indirect interactions, respectively. Different node shapes represent the functional class of the gene product. Red and green nodes represent overexpressed and underexpressed genes in each comparison.</p

Gene set enrichment analysis in closed pyometra detected by IPA analysis.

<p>Gene set enrichment analysis in closed pyometra detected by IPA analysis.</p

Supervised hierarchical clustering analysis of global gene expression data.

<p>Supervised analysis according to: <b>A:</b> absence or presence of previous exogenous progesterone treatment in female dogs with CEH, mucometra and pyometra; <b>B</b>. absence or presence of previous exogenous progesterone treatment in female dogs with pyometra. <b>C:</b> cervix condition in pyometra (open versus closed).</p