Pathway Analysis of Differentially Expressed Genes in Patients with Acute Aortic Dissection

Background: Acute aortic dissection (AAD) is a life-threatening condition with high mortality and a relatively unclarified pathophysiological mechanism. Although differentially expressed genes in AAD have been recognized, interactions between these genes remain poorly defined. This study was conducted to gain a better understanding of the molecular mechanisms underlying AAD and to support the future development of a clinical test for monitoring patients at high risk. Materials and Methods: Aortic tissue was collected from 19 patients with AAD (mean age 61.7 ± 13.1 years), and from eight other patients (mean age 32.9 ± 12.2 years) who carried the mutated gene for Marfan syndrome (MS). Six patients (mean age 56.7 ± 12.3 years) served as the control group. The PIQOR TM Immunology microarray with 1076 probes in quadruplicates was utilized; the differentially expressed genes were analysed in a MedScan search using PathwayAssist software. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and protein analysis were performed. Results: Interactions of MS fibrillin-1 (FBN1) in the MedScan pathway analysis showed four genes, fi bulin-1 (FBLN1), fi bulin-2 (FBLN2), decorin (DCN) and microfi brillar associated protein 5 (MFAP5), which were differentially expressed in all tissue from AAD. The validation of these genes by qRT-PCR revealed a minimum of three-fold downregulation of FBLN1 (0.5 ± 0.4 vs. 6.1 ± 2.3 fold, p = 0.003) and of DCN (2.5 ± 1.0 vs. 8.5 ± 4.7 fold, p = 0.04) in AAD compared to MS and control samples. Conclusions: Downregulation of fibrillin-1 (FBN1) may weaken extracellular components in the aorta and/or interfer with the transmission of cellular signals and eventually cause AAD. Additional research on these four identified genes can be a starting point to develop a diagnostic tool

Gross genetic alterations and genetic heterogeneity in a periductal stromal tumor of the breast

Background!#!Periductal stromal tumors of the breast are exceedingly rare biphasic breast tumors with close morphological relationship to phyllodes tumors. So far, results of genetic analyses on these tumors have not been reported.!##!Case presentation!#!A 50 year old female patient was admitted to the hospital because of a palpable lump in her right breast with a diameter of approximately 5-6 cm which was surgically removed by lumpectomy. Histologic examination revealed a biphasic breast tumor classified as periductal stromal tumor. Array analysis showed a pseudotetraploid tumor with a copy number of 4 for most of the chromosomes. In addition, further changes of chromosomes 1, 5, and 6 were noted but there were no mutations of MED12 as those frequently seen in fibroadenomas or phyllodes tumors.!##!Conclusions!#!The genetic alterations observed indicate karyotypic evolution leading to marked heterogeneity which fits with the tumor´s histologic and cytologic appearance as well as with its malignant behavior. Because of the absence of genetic similarities with phyllodes tumors, the case does not offer evidence for a common entity but rather suggests the existence of two independent entities

Permanent activation of HMGA2 in lipomas mimics its temporal physiological activation linked to the gain of adipose tissue

Objective: In this study the activation of HMGA2 and overexpression by FGF1-driven stimulation of adipose tissue derived stem cells (ADSCs) in adipose tissue tumors were analyzed. In addition, the expression of HMGA2 and PPAR-gamma mRNA were quantified in canine subcutaneous abdominal adipose tissue from normal and overweight purebred dogs. Design and Methods: ADSCs and adipose tissue explants stimulated with FGF1 followed by gene expression analyses of HMGA2 and p14Arf using Western-blot and qRT-PCR. Furthermore, canine subcutaneous white adipose tissue (WAT) were analyzed by qRT-PCR for their expression of HMGA2 and PPAR-gamma. Results: ADSCs and adipose tissue explants are able to execute a HMGA2 response upon FGF1 stimulation. FGF1 enhances proliferation of ADSCs by a HMGA2-dependent mechanism. In lipomas increase of HMGA2 is accompanied by increased expression of p14Arf. Furthermore, a significantly elevated level of HMGA2 in overweight dogs and a negative correlation between the expression of HMGA2 and PPAR-gamma in subcutaneous cWAT were noted. Conclusions: These results suggest that WAT contains cells that as essential part of adipogenesis up-regulate HMGA2 resulting from growth factor stimulation. In subgroups of lipoma, constitutive activation of HMGA2 due to rearrangements replaces the temporal response triggered by growth factors

Locally Different Endothelial Nitric Oxide Synthase Protein Levels in Ascending Aortic Aneurysms of Bicuspid and Tricuspid Aortic Valve

Aims. Dysregulated expression of the endothelial nitric oxide synthase (eNOS) is observed in aortic aneurysms associated with bicuspid aortic valve (BAV). We determined eNOS protein levels in various areas in ascending aortic aneurysms. Methods and Results. Aneurysmal specimens were collected from 19 patients, 14 with BAV and 5 with tricuspid aortic valve (TAV). ENOS protein levels were measured in the outer curve (convexity), the opposite side (concavity), the distal and above the sinotubular junction (proximal) aneurysm. Cultured aortic cells were treated with NO synthesis inhibitor L-NAME and the amounts of 35 apoptosis-related proteins were determined. In patients with BAV, eNOS levels were significantly lower in the proximal aorta than in the concavity and distal aorta. ENOS protein levels were also lower in the convexity than in the concavity. While the convexity and distal aorta showed similar eNOS protein levels in BAV and TAV patients, levels were higher in TAV proximal aorta. Inhibition of NO synthesis in aneurysmal aortic cells by L-NAME led to a cytosolic increase in the levels of mitochondrial serine protease HTRA2/Omi. Conclusion. ENOS protein levels were varied at different areas of the aneurysmal aorta. The dysregulation of nitric oxide can lead to an increase in proapoptotic HTRA2/Omi

Upregulation of the high mobility group AT-hook 2 gene in acute aortic dissection is potentially associated with endothelial-mesenchymal transition

The high mobility group AT-hook 2 (HMGA2) gene is proposed to regulate the genes involved in the epithelial-mesenchymal transition (EMT). One form of EMT is endothelial-mesenchymal transition (EndMT). We analyzed the expression profile of the HMGA2 gene in different human aortic diseases. Aortic specimens were collected from 51 patients, including 19 with acute aortic dissection, 26 with aortic aneurysm, two with Marfan syndrome and four aortic valves. Quantitative real-time polymerase chain reaction was carried out for HMGA2 and immunohistochemical analyses were performed for HMGA2, SNAI1, Vimentin, CD34, MKI-67 and TGFB1. The expression of let-7d microRNA, which is assumed to play a role in the regulation of HMGA2, was also quantified. The level of HMGA2 gene expression was significantly higher in acute aortic dissection compared with all the other samples (193.1 vs. 8.1 fold normalized to calibrator, P<0.001). The immunohistochemical investigation showed that HMGA2, SNAI1, and Vimentin proteins were mainly detected in the endothelial cells of the vasa vasorum. The HMGA2 gene is upregulated in acute aortic dissection. This is the first report describing a link between HMGA2 and acute aortic dissection. The HMGA2, SNAI1 and Vimentin proteins were mainly detected in the endothelium of the vasa vasorum. It seems that HMGA2 overexpression in acute aortic dissection occurs in a let-7d-independent manner and is associated with EndMT of the vasa vasorum