Search tips
Search criteria

Results 1-5 (5)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
1.  Novel pathways in the pathobiology of human abdominal aortic aneurysms 
Abdominal aortic aneurysm (AAA), a dilatation of the infrarenal aorta, typically affects males > 65 years. The pathobiological mechanisms of human AAA are poorly understood. The goal of this study was to identify novel pathways involved in the development of AAAs.
A custom-designed “AAA-chip” was used to assay 43 of the differentially expressed genes identified in a previously published microarray study between AAA (n = 15) and control (n = 15) infrarenal abdominal aorta. Protein analyses were performed on selected genes.
Altogether 38 of the 43 genes on the “AAA-chip” showed significantly different expression. Novel validated genes in AAA pathobiology included ADCY7, ARL4C, BLNK, FOSB, GATM, LYZ, MFGE8, PRUNE2, PTPRC, SMTN, TMODI and TPM2. These genes represent a wide range of biological functions, such as calcium signaling, development and differentiation, as well as cell adhesion not previously implicated in AAA pathobiology. Protein analyses for GATM, CD4, CXCR4, BLNK, PLEK, LYZ, FOSB, DUSP6, ITGA5 and PTPRC confirmed the mRNA findings.
The results provide new directions for future research into AAA pathogenesis to study the role of novel genes confirmed here. New treatments and diagnostic tools for AAA could potentially be identified by studying these novel pathways.
PMCID: PMC3782105  PMID: 22797469
gene expression; vascular biology; aorta; abdominal aortic aneurysm
2.  Identification, basic characterization and evolutionary analysis of differentially spliced mRNA isoforms of human YAP1 gene 
Gene  2012;509(2):215-222.
The YAP1 gene encodes a potent new oncogene and stem cell factor. However, in some cancers, the YAP1 gene plays a role of tumor suppressor. At present, the gene and its products are intensely studied and its cDNAs are used as transgenes in cellular and animal models. Here, we report 4 new potential mRNA splicing isoforms of the YAP1 gene, bringing the total number of isoforms to 8. We detected all 8 YAP1 isoforms in a panel of human tissues and evaluated the expression of the longest isoform of YAP1 (YAP1-2δ) using Real Time PCR. All YAP1 isoforms are barely detectable in human leukocytes compared to fair levels of expression found in other human tissues. We analyzed the structure of the genomic region that gave rise to alternatively spliced YAP1 transcripts in different metazoans. We found that YAP1 isoforms, which utilize exon 6 emerged in evolution with the appearance of amniotes. Interestingly, 6 YAP1 isoforms, which contain the exon 5 extension, exon 6 or both would have their leucine zipper region disrupted in the predicted protein product, compared to the intact leucine zipper found in two YAP1 (α) isoforms. This observation has direct functional ramifications for YAP1 signaling. We also propose a normalized nomenclature for the mRNA splice variants of YAP1 gene, which should aid in the characterization of signaling differences among the potential protein products of the YAP1 gene.
PMCID: PMC3455135  PMID: 22939869
Alternative splicing; WW domains; Leucine Zipper; Quantitative RT-PCR
3.  Role of Complement Cascade in Abdominal Aortic Aneurysms 
The goal of this study was to investigate the role of complement cascade genes in the pathobiology of human abdominal aortic aneurysms (AAAs).
Methods and Results
Results of a genome-wide microarray expression profiling revealed 3,274 differentially expressed genes between aneurysmal and control aortic tissue. Interestingly, 13 genes in the complement cascade were significantly differentially expressed between AAA and the controls. In silico analysis of the promoters of the 13 complement cascade genes showed enrichment for transcription factor binding sites for STAT5A. Chromatin-immunoprecipitation experiments demonstrated binding of transcription factor STAT5A to the promoters of the majority of the complement cascade genes. Immunohistochemical analysis showed strong staining for C2 in AAA tissues.
These results provide strong evidence that the complement cascade plays a role in human AAA. Based on our microarray studies, the pathway is activated in AAA, particularly via the lectin and classical pathways. The overrepresented binding sites of transcription factor STAT5A in the complement cascade gene promoters suggest a role for STAT5A in the coordinated regulation of complement cascade gene expression.
PMCID: PMC3712630  PMID: 21493888
Abdominal aortic aneurysm; complement cascade; genetic association study; STAT5; chromatin immunoprecipitation
4.  Regional expression of HOXA4 along the aorta and its potential role in human abdominal aortic aneurysms 
BMC Physiology  2011;11:9.
The infrarenal abdominal aorta exhibits increased disease susceptibility relative to other aortic regions. Allograft studies exchanging thoracic and abdominal segments showed that regional susceptibility is maintained regardless of location, suggesting substantial roles for embryological origin, tissue composition and site-specific gene expression.
We analyzed gene expression with microarrays in baboon aortas, and found that members of the HOX gene family exhibited spatial expression differences. HOXA4 was chosen for further study, since it had decreased expression in the abdominal compared to the thoracic aorta. Western blot analysis from 24 human aortas demonstrated significantly higher HOXA4 protein levels in thoracic compared to abdominal tissues (P < 0.001). Immunohistochemical staining for HOXA4 showed nuclear and perinuclear staining in endothelial and smooth muscle cells in aorta. The HOXA4 transcript levels were significantly decreased in human abdominal aortic aneurysms (AAAs) compared to age-matched non-aneurysmal controls (P < 0.00004). Cultured human aortic endothelial and smooth muscle cells stimulated with INF-γ (an important inflammatory cytokine in AAA pathogenesis) showed decreased levels of HOXA4 protein (P < 0.0007).
Our results demonstrated spatial variation in expression of HOXA4 in human aortas that persisted into adulthood and that downregulation of HOXA4 expression was associated with AAAs, an important aortic disease of the ageing population.
PMCID: PMC3125234  PMID: 21627813
5.  Transcriptional profile of Rous Sarcoma Virus transformed chicken embryo fibroblasts reveals new signaling targets of viral-src 
Virology  2007;364(1):10-20.
Transformation of chicken fibroblasts in vitro by Rous Sarcoma Virus represents a model of cancer in which a single oncogene, viral src, uniformly and rapidly transforms primary cells in culture. We experimentally surveyed the transcriptional program affected by Rous Sarcoma Virus (RSV) in primary culture of chicken embryo fibroblasts. As a control, we used cells infected with non-transforming RSV mutant td106, in which the src gene was deleted. Using Affymetrix GeneChipR Chicken Genome Arrays, we report 811 genes that were modulated more than 2.5 fold in the virus transformed cells. Among these, 409 genes were induced and 402 genes were repressed by viral src. From the repertoire of modulated genes, we selected 20 genes that were robustly changed. We then validated and quantified the transcriptional changes of most of the 20 selected genes by real-time PCR. The set of strongly induced genes contains vasoactive intestinal polypeptide, MAP kinase phosphatase 2 and follistatin, among others. The set of strongly repressed genes contains TGF beta 3, TGF beta-induced gene, and deiodinase. The function of several robustly modulated genes sheds new light on the molecular mechanism of oncogenic transformation.
PMCID: PMC1974879  PMID: 17448514
avian sarcoma; Schmidt-Ruppin strain of RSV; src oncogene; protein-tyrosine kinase; vasoactive intestinal polypeptide; MAP kinase phosphatase 2; follistatin

Results 1-5 (5)