Biomedical subjects

Mahnaz Bonrouhi

Publications and source records attributed to Mahnaz Bonrouhi.

6 recordsLinked to original sources

PubMed2005

Cell-specific deletion of glucosylceramide synthase in brain leads to severe neural defects after birth.

Sialic acid-containing glycosphingolipids, i.e., gangliosides, constitute a major component of neuronal cells and are thought to be essential for brain function. UDP-glucose:ceramide glucosyltransferase (Ugcg) catalyzes the initial step of glycosphingolipid (GSL) biosynthesis. To gain insight into the role of GSLs in brain development and function, a cell-specific disruption of Ugcg was performed as indicated by the absence of virtually all glucosylceramide-based GSLs. Shortly after birth, mice showed dysfunction of cerebellum and peripheral nerves, associated with structural defects. Axon branching of Purkinje cells was significantly reduced. In primary cultures of neurons, dendritic complexity was clearly diminished, and pruning occurred early. Myelin sheaths of peripheral nerves were broadened and focally severely disorganized. GSL deficiency also led to a down-regulation of gene expression sets involved in brain development and homeostasis. Mice died approximately 3 weeks after birth. These results imply that GSLs are essential for brain maturation.

Animals↗

PubMed2005

13-cis retinoic acid inhibits development and progression of chronic allograft nephropathy.

Chronic allograft nephropathy is characterized by chronic inflammation and fibrosis. Because retinoids exhibit anti-proliferative, anti-inflammatory, and anti-fibrotic functions, the effects of low and high doses of 13-cis-retinoic acid (13cRA) were studied in a chronic Fisher344-->Lewis transplantation model. In 13cRA animals, independent of dose (2 or 20 mg/kg body weight/day) and start (0 or 14 days after transplantation) of 13cRA administration, serum creatinine was significantly lower and chronic rejection damage was dramatically reduced, including subendothelial fibrosis of preglomerular vessels and chronic tubulointerstitial damage. The number of infiltrating mononuclear cells and their proliferative activity were significantly diminished. The mRNA expression of chemokines (MCP-1/CCL2, MIP-1alpha/CCL3, IP-10/CXCL10, RANTES/CCL5) and proteins associated with fibrosis (plasminogen activator inhibitor-1, transforming growth factor-beta1, and collagens I and III) were strikingly lower in treated allografts. In vitro, activated peritoneal macrophages of 13cRA-treated rats showed a pronounced decrease in protein secretion of inflammatory cytokines (eg, tumor necrosis factor-alpha, interleukin-6). The suppression of the proinflammatory chemokine RANTES/CCL5 x 13cRA in fibroblasts could be mapped to a promoter module comprising IRF-1 and nuclear factor-kappaB binding elements, but direct binding of retinoid receptors to promoter elements could be excluded. In summary, 13cRA acted as a potent immunosuppressive and anti-fibrotic agent able to prevent and inhibit progression of chronic allograft nephropathy.

Animals↗

PubMed2004

High-accuracy amplification of nanogram total RNA amounts for gene profiling.

Microarray-based gene profiling of laser-assisted microdissected tissues or clinical biopsies is still a challenge since the amount of total RNA in such samples is limited and amplification of RNA is mandatory. Representative amplification of mRNA is highly dependent on the reverse transcription reaction, which is error prone, and on the number of amplification cycles. To improve the accuracy of RNA amplification, we optimized, combined, and tested different amplification strategies for Affymetrix oligonucleotide array hybridization. We demonstrate that different protocols differ significantly in quality of mRNA amplification. To demonstrate the accuracy and reproducibility of our optimized protocol in a clinical setting, we analyzed total RNAs from laser-assisted, microdissected cells of human prostate tissues. On the basis of these results, we recommend a standard reverse transcription reaction for small-sample-transcriptome profiling experiments as part of the Minimal Information about a Microarray Experiment (MIAME) set of standards.

Animals↗

PubMed2004

Influence of native and hypochlorite-modified low-density lipoprotein on gene expression in human proximal tubular epithelium.

Inflammatory infiltrates can modify (lipo)proteins via hypochlorous acid/hypochlorite (HOCl/OCl(-)) an oxidant formed by the myeloperoxidase-H(2)O(2)-halide system. These oxidatively modified proteins emerge in tubuli in some proteinuric and interstitial diseases. Human proximal tubular cells (HK-2) were used to confirm the hypothesis of detrimental and differential impact of HOCl-modified low density lipoprotein (HOCl-LDL), an in vivo occurring lipoprotein modification exerting proatherogenic and proinflammatory capacity. HOCl-LDL showed dose-dependent antiproliferative effects in HK-2 cells. Small dedicated cDNA macroarrays were used to identify differentially regulated genes. A rapid increase in the expression of genes involved in reactive oxygen species metabolism and cell stress, eg, heme oxygenase-1, thioredoxin reductase, cytochrome b5 reductase, Gadd 153, amino acid transporter E16, and HSP70 was found after HOCl-LDL treatment of HK-2 cells. In parallel, genes involved in tissue remodeling and inflammation eg, CTGF, VCAM-1, IL-1beta, MMP7, and VEGF were up-regulated. Quantitative RT-PCR verified differential expression of a subset of these genes in microdissected tubulointerstitia from patients with acute tubular damage, progressive proteinuric renal disease, and membranous glomerulonephritis (with declining renal function), but not in stable patients with proteinuria caused by minimal change disease. The demonstration of selective up-regulation of a subgroup of genes if proteinuria is accompanied by the presence of HOCl-modified (lipo)proteins support the potential pathophysiological role of the myeloperoxidase-H(2)O(2)-halide system and HOCl-LDL in renal disease.

Adult↗

PubMed2004

Gene expression fingerprints in human tubulointerstitial inflammation and fibrosis as prognostic markers of disease progression.

BACKGROUND: Gene expression profiling of nephropathies may facilitate development of diagnostic strategies for complex renal diseases as well as provide insight into the molecular pathogenesis of kidney diseases. To test molecular based renal disease categorization, differential gene expression profiles were compared between control and hydronephrotic kidneys showing varying degrees of inflammation and fibrosis. METHODS: RNA expression profiles from 9 hydronephrotic and 3 control kidneys were analyzed using small macroarrays dedicated to genes involved in cell-cell contact, matrix turnover, and inflammation. In parallel, the degree of tubulointerstitial inflammation, fibrosis, and tubular atrophy using light microscopy and quantitative immunohistochemical parameters was determined. RESULTS: Hierarchic clustering and self-organizing maps led to a gene expression dendrogram with three distinct nodes representing the control group, four kidneys with high inflammation, and five kidneys giving high fibrosis scores. To evaluate the clinical applicability of the marker set, the expression of nine genes (6Ckine, IL-8, MMP-9, MMP-3, MMP-7, urokinase R, CXCR5, integrin-beta4, and pleiotrophin) was tested in tubulointerstitial samples from routine renal biopsies. Seven mRNA markers showed differential regulation in inflammation and fibrosis in the biopsy population. Clinical follow-up revealed stringent correlation between gene expression data and progression of renal disease, and allowed segregation of the biopsies into progressive or stable disease course based on gene expression profiles. CONCLUSION: This study suggests the feasibility of gene expression-based disease categorization in human nephropathies based on the extraction of marker gene sets.

Adult↗

PubMed2002

Decrease and gain of gene expression are equally discriminatory markers for prostate carcinoma: a gene expression analysis on total and microdissected prostate tissue.

Information on over- and underexpressed genes in prostate cancer in comparison to adjacent normal tissue was sought by DNA microarray analysis. Approximately 12,600 mRNA sequences were analyzed from a total of 26 tissue samples (17 untreated prostate cancers, 9 normal adjacent to prostate cancer tissues) obtained by prostatectomy. Hierarchical clustering was performed. Expression levels of 63 genes were found significantly (at least 2.5-fold) increased, whereas expression of 153 genes was decreased (at least 2.5-fold) in prostate cancer versus adjacent normal tissue. In addition to previously described genes such as hepsin, overexpression of several genes was found that has not drawn attention before, such as the genes encoding the specific granule protein (SGP28), alpha-methyl-acyl-CoA racemase, low density lipoprotein (LDL)-phospholipase A2, and the anti-apoptotic gene PYCR1. The radiosensitivity gene ATDC and the genes encoding the DNA-binding protein inhibitor ID1 and the phospholipase inhibitor uteroglobin were significantly down-regulated in the cancer samples. DNA microarray data for eight genes were confirmed quantitatively in five normal and five cancer tissues by real-time reverse transcriptase-polymerase chain reaction with a high correlation between the two methods. Laser capture microdissection of epithelial and stromal compartments from cancer and histological normal specimens followed by an amplification protocol for low levels of RNA (<0.1 microg) allowed us to distinguish between gene expression profiles characteristic of epithelial cells and those typical of stroma. Most of the genes identified in the nonmicrodissected tumor material as up-regulated were indeed overexpressed in cancerous epithelium rather than in the stromal compartment. We conclude that development of prostate cancer is associated with down-regulation as well as up-regulation of genes that show complex differential regulation in epithelia and stroma. Some of the gene expression alterations identified in this study may prove useful in the development of novel diagnostic and therapeutic strategies.

Adenocarcinoma↗