Cellular fibronectins are differentially expressed in human fetal and adult kidney

The localization of cellular forms of fibronectin (cFn) was studied in fetal and adult kidneys. We used monoclonal antibodies reacting with the extradomains A and B in cFN (EDAcFn, EDBcFn) as well as with a differentially glycosylated fetal form of the protein (Onc-cFn). In adult human kidney EDAcFn was present in glomerular mesangium and in the walls of larger blood vessels, whereas a polyclonal rabbit fibronectin antiserum widely reacted also with interstitial areas. Immunoreactivity for EDBcFn and Onc-cFn, however, was not found in adult kidney. In the basement membranes and interstitial areas of developing tubules and glomeruli the immunoreactivity for EDAcFn was distinct and detectable in the earlier stages also for EDBcFn. In developing glomeruli, EDAcFn and EDBcFn were detected in teh mesangial areas, but in more mature fetal glomeruli, the mesangial immunoreactivity only persisted for EDAcFn. Both EDAcFn and EDBcFn were found in the basement membranes in the medullary area of all developing kidneys. In fetal kidney, immunoreactivity for EDAcFn and EDBcFn was seen also in small blood vessels, including the capillaries. Immunoreactivity for Onc-cFn was found in mesangial cells of fetal glomeruli as well as in the intima of larger blood vessels but not in the basement membranes. The results show that the three forms of cFn are present in the fetal kidney and have certain differences in their distribution. Conversely, only the EDAcFn was detected in the adult kidney. The different, partially age-related distributions of the three types of cFns suggest that they may also differ in their functions.     

In search of candidate genes critically expressed in the human endometrium during the window of implantation

BACKGROUND: In this prospective randomized blinded clinical trial, we examined gene expression profiles of the human endometrium during the early and mid-luteal phases of the natural cycle. METHODS: An endometrial biopsy was performed on day 16 (LH +3) or on day 21 (LH +8), followed by RNA extraction and microarray analysis using an Affymetrix HG-U95A microchip. Data analysis was carried out using pairwise multiple group comparison with the significance analysis of microarrays (SAM) software. RESULTS: With a false discovery rate of 0, the analysis revealed that 107 genes were significantly and differently expressed (> or =2-fold) during the early versus the mid-luteal phase of the cycle. Forty-five of these genes have not been previously linked to endometrial receptivity. Validation of the microarray data was accomplished using semiquantitative RT-PCR. We demonstrated the presence of estrogen and progesterone response elements (ERE and PRE) by analysis of the 5'-flanking regions of a subset of differentially regulated genes. CONCLUSIONS: Using a strict bioinformatics approach of microarray data, we demonstrated significant changes in candidate genes during the transition of the early to the mid-luteal phase of the human endometrium that may have functional significance for the opening and maintenance of the window of implantation.     

HER3 and HER4 are highly expressed in human meningiomas

HER3 and HER4 are tyrosine kinase receptors of the ErbB family that have been detected in several cancers but lack substantial investigation in human meningiomas. In this study, HER3 and -4 expression levels were evaluated as potential biomarkers by immunohistochemistry and explored for association to clinical features in a large series of human meningiomas. 186 primary intracranial meningiomas from adult patients were investigated with antibodies against HER3 and -4 intracellular domains. Tumors were scored with a staining index (SI) based on cytoplasmic/membranous staining intensity and on the percentage of positive cells. SIs were tested for associations with WHO malignancy grade, tumor subtype, localization, and prognosis. HER3 and HER4 were highly expressed in most tumors. Both cytoplasmic and membranous immunoreactivity occurred, and for HER4 nuclear immunoreactivity was observed as well. Non-neoplastic meningeal tissue was not immunoreactive. HER3 and -4 immunoreactivity was not associated with WHO malignancy grade, nor with recurrence or survival in adjusted analyses. Meningiomas of all grades were shown to widely express both HER3 and HER4 receptors. This feature may have diagnostic value since non-neoplastic meninges were not immunoreactive. There was no prognostic significance in adjusted survival analyses.     

Telomerase promoter reprogramming and interaction with general transcription factors in the human mesenchymal stem cell

The human adult mesenchymal stem cell (hMSC) does not express telomerase and has been shown to be the target for neoplastic transformation after transduction with hTERT. These findings lend support to the stem cell hypothesis of cancer development but by supplying hTERT, the molecular events required to upregulate hTERT expression in cancer development are missed. Therefore, the hMSC is ideal for the identification of molecular mechanisms regulating telomerase gene expression in stem cells. This study shows that the repression of hTERT expression in hMSC is chromatin based and that modifications of the chromatin environment lead to reactivation of telomerase gene expression. It is shown that repression of hTERT expression in hMSCs is due to promoter-specific histone hypoacetylation coupled with low Pol II and TFIIB trafficking. This repression is overcome by treatment with Trichostatin A (TSA), an HDAC inhibitor, concomitant with increases in promoter-specific histone acetylation and increases in Pol II and TFIIB tracking. hTR expression is also increased in TSA-treated hMSCs, concomitant with changes in Pol II and TFIIB dynamics.     

OCT4 spliced variants are differentially expressed in human pluripotent and nonpluripotent cells

OCT4 is a master regulator of self-renewal in embryonic stem cells and can potentially encode two spliced variants, designated OCT4A and OCT4B. We have examined the expression pattern of these OCT4 isoforms in various human pluripotent and nonpluripotent cells. Our data revealed that whereas OCT4A expression is restricted to embryonic stem (ES) and embryonal carcinoma (EC) cells, OCT4B can be detected in various nonpluripotent cell types. Furthermore, we detected a novel OCT4 spliced variant, designated OCT4B1, that is expressed primarily in human ES and EC cells and is downregulated following their differentiation. We also found a significantly higher level of OCT4B1 expression in stage-specific embryonic antigen-3 (SSEA3)(+) compared with SSEA3(-) subpopulations of cultured ES cells. Taken together, our data demonstrated a distinctive expression pattern for OCT4 spliced variants in different cell types and highlight the necessity of defining the type of OCT4 when addressing the expression of this gene in different human cells.     

DOK4 and DOK5: new Dok-related genes expressed in human T cells

Dok proteins are adapter proteins involved in signal transduction. Several intracellular proteins expressed in lymphocytes meet the criteria of membrane-associated adapter proteins such as members of the Dok family. To understand the role and the formation of multiprotein networks involving Dok proteins in T lymphocytes, we search for potential additional members of this family. Here, we describe the two new human dok-related genes DOK4 and DOK5 and present data showing the expression of DOK4 and DOK5 genes in T cells. These genes are the orthologues of mouse Dok4 and Dok5 genes. Based on analysis of phylogenetic trees and exon/intron structure of Dok family members, DOK4 and DOK5 define a subfamily within dok genes distinct from DOK1, DOK2 and DOK3. So, Dok-4 and Dok-5 molecules constitute a new group of adapter proteins in T cells, requiring further functional analysis.     

Synaptic genes are extensively downregulated across multiple brain regions in normal human aging and Alzheimer's disease

Synapses are essential for transmitting, processing, and storing information, all of which decline in aging and Alzheimer's disease (AD). Because synapse loss only partially accounts for the cognitive declines seen in aging and AD, we hypothesized that existing synapses might undergo molecular changes that reduce their functional capacity. Microarrays were used to evaluate expression profiles of 340 synaptic genes in aging (20–99 years) and AD across 4 brain regions from 81 cases. The analysis revealed an unexpectedly large number of significant expression changes in synapse-related genes in aging, with many undergoing progressive downregulation across aging and AD. Functional classification of the genes showing altered expression revealed that multiple aspects of synaptic function are affected, notably synaptic vesicle trafficking and release, neurotransmitter receptors and receptor trafficking, postsynaptic density scaffolding, cell adhesion regulating synaptic stability, and neuromodulatory systems. The widespread declines in synaptic gene expression in normal aging suggests that function of existing synapses might be impaired, and that a common set of synaptic genes are vulnerable to change in aging and AD.     

Differentially expressed genes in a porcine adult hepatic stem-like cell line and their expression in developing and regenerating liver

To identify differentially expressed genes in adult hepatic stem cells, we performed suppression-subtractive hybridization (SSH) between adult porcine hepatic stem-like cells (HSLCs) and hepatocytes, and the expression of selected genes was assessed in porcine fetal livers and regenerating liver in an 80% hepatectomy model. SSH and subsequent differential screening selected 39 clones that were expressed differentially in HSLCs, including six known genes, 10 unknown genes, one unidentified gene and some chimeric fragments. Four of these genes showed significantly higher expression in HSLCs than in mature hepatocytes: anti-leukoproteinase, matrix Gla protein, amyloid-beta precursor protein (APP) and dickkopf-3 (DKK-3). Among them, the mRNA expression of APP and DKK-3 was significantly higher in fifth GW fetal liver than in seventh and thirteenth GW fetal and adult livers, unlike the expression patterns of alpha-fetoprotein (AFP) or albumin. These mRNAs were detected in the parenchyma of fifth GW fetal liver, whereas in normal adult liver possible expression was limited to the periportal area. On the other hand, immunohistochemistry, Masson's trichrome staining and silver impregnation demonstrated APP and DKK-3 proteins in fifth GW fetal liver in which intralobular bile ducts and hepatic plates had not completely developed. DKK-3 and AFP mRNAs were upregulated on the seventh day (7D) after 80% hepatectomy. In the liver tissue, DKK-3 and AFP proteins were detected in mesenchymal cells in the periportal area and parenchyma, respectively. These data for DKK-3 expression in adult livers suggest the possible presence of adult HSLCs in the periportal area. The pattern of histological staining suggested that 7D liver was in the process of regeneration, showing a character similar to the fifth GW fetal liver. It is speculated that DKK-3 is upregulated in immature and developing livers, and has possible involvement in hepatic differentiation and liver regeneration.