scholarly journals Cell-cell contact regulates gene expression in CDK4-transformed mouse podocytes

2010 ◽  
Vol 299 (4) ◽  
pp. F802-F809 ◽  
Author(s):  
Toru Sakairi ◽  
Yoshifusa Abe ◽  
Parmijit S. Jat ◽  
Jeffrey B. Kopp

We transformed mouse podocytes by ectopic expression of cyclin-dependent kinase 4 (CDK4). Compared with podocytes transformed with a thermo-sensitive SV40 large T antigen mutant tsA58U19 (tsT podocytes), podocytes transformed with CDK4 (CDK4 podocytes) exhibited significantly higher expression of nephrin mRNA. Synaptopodin mRNA expression was significantly lower in CDK4 podocytes and in tsT podocytes under growth-permissive conditions (33°C) compared with tsT podocytes under growth-restricted conditions (37°C), which suggests a role for cell cycle arrest in synaptopodin mRNA expression. Confluent CDK4 podocytes showed significantly higher mRNA expression levels for nephrin, synaptopodin, Wilms tumor 1, podocalyxin, and P-cadherin compared with subconfluent cultures. We carried out experiments to clarify roles of various factors in the confluent podocyte cultures; our findings indicate that cell-cell contact promotes expression of five podocyte marker genes studied, that cellular quiescence increases synaptopodin and podocalyxin mRNA expression, and that soluble factors play a role in nephrin mRNA expression. Our findings suggest that CDK4 podocytes are useful tools to study podocyte biology. Furthermore, the role of cell-cell contact in podocyte gene expression may have relevance for podocyte function in vivo.

1994 ◽  
Vol 267 (5) ◽  
pp. E629-E635 ◽  
Author(s):  
D. J. Drucker

The gene encoding proglucagon is expressed in the pancreas, intestine, and brain. The molecular determinants of proglucagon gene expression and the biological activities of the proglucagon-derived peptides (PGDPs) have been examined using transgenic mice harboring a glucagon-SV40 large T antigen (GLUTag) transgene. These experiments have delineated DNA sequences important for intestinal-specific proglucagon gene transcription. GLUTag mice develop neuroendocrine tumors of the pancreas and large bowel, leading to elevated plasma levels of the PGDPs and suppression of endogenous proglucagon gene expression. Transplantation of the large bowel tumors subcutaneously into nude mice provides additional evidence for inhibition of endogenous pancreatic proglucagon gene expression by one or more of the tumor-derived PGDPs. The large bowel GLUTag tumors exhibit abnormalities in the posttranslational processing of proglucagon. GLUTag tumors may be passaged in vivo and in vitro and have been used to generate stable cell lines that express the proglucagon gene at high levels. Taken together, these studies highlight the utility of transgenic systems for the physiological analysis of hormone action and the molecular determinants of peptide hormone gene expression.


1998 ◽  
Vol 275 (6) ◽  
pp. C1473-C1480 ◽  
Author(s):  
Kenneth M. Hershman ◽  
Edwin S. Levitan

Regulation of voltage-gated K+channel genes represents an important mechanism for modulating cardiac excitability. Here we demonstrate that expression of two K+channel mRNAs is reciprocally controlled by cell-cell interactions between adult cardiac myocytes. It is shown that culturing acutely dissociated rat ventricular myocytes for 3 h results in a dramatic downregulation of Kv1.5 mRNA and a modest upregulation of Kv4.2 mRNA. These effects are specific, because similar changes are not detected with other channel mRNAs. Increasing myocyte density promotes maintenance of Kv1.5 gene expression, whereas Kv4.2 mRNA expression was found to be inversely proportional to cell density. Conditioned culture medium did not mimic the effects of high cell density. However, paraformaldehyde-fixed myocytes were comparable to live cells in their ability to influence K+channel message levels. Thus the reciprocal effects of cell density on the expression of Kv1.5 and Kv4.2 genes are mediated by direct contact between adult cardiac myocytes. These findings reveal for the first time that cardiac myocyte gene expression is influenced by signaling induced by cell-cell contact.


2010 ◽  
Vol 298 (3) ◽  
pp. F557-F567 ◽  
Author(s):  
Toru Sakairi ◽  
Yoshifusa Abe ◽  
Hiroshi Kajiyama ◽  
Linda D. Bartlett ◽  
Lilian V. Howard ◽  
...  

Evidence suggests that loss of podocytes into urine contributes to development of glomerular diseases; shed podocytes are frequently viable and proliferate in culture conditions. To determine the phenotypic characteristics of viable urinary cells derived from human subjects, we established long-term urinary cell culture from two patients with focal segmental glomerulosclerosis and two healthy volunteers, via transformation with the thermosensitive SV40 large T antigen (U19tsA58) together with human telomerase (hTERT). Characterization of arbitrarily selected two clonal cell lines from each human subject was carried out. mRNA expression for the podocyte markers synaptopodin, nestin, and CD2AP were detected in all eight clones. Podocin mRNA was absent from all eight clones. The expression of nephrin, Wilms' tumor 1 (WT1), and podocalyxin mRNA varied among the clones, which may be due to transformation and/or cloning. These results suggest that podocyte cell lines can be established consistently from human urine. The generation of podocyte cell lines from urine of patients and healthy volunteers is novel and will help to advance studies of podocyte cell biology. Further improvements in the approaches to cell transformation and/or cell culture techniques are needed to allow cultured podocytes to fully reproduce in vivo characteristics.


Blood ◽  
2008 ◽  
Vol 111 (10) ◽  
pp. 5223-5232 ◽  
Author(s):  
Naoshi Obara ◽  
Norio Suzuki ◽  
Kibom Kim ◽  
Toshiro Nagasawa ◽  
Shigehiko Imagawa ◽  
...  

Abstract In response to anemia, erythropoietin (Epo) gene transcription is markedly induced in the kidney and liver. To elucidate how Epo gene expression is regulated in vivo, we established transgenic mouse lines expressing green fluorescent protein (GFP) under the control of a 180-kb mouse Epo gene locus. GFP expression was induced by anemia or hypoxia specifically in peritubular interstitial cells of the kidney and hepatocytes surrounding the central vein. Surprisingly, renal Epo-producing cells had a neuronlike morphology and expressed neuronal marker genes. Furthermore, the regulatory mechanisms of Epo gene expression were explored using transgenes containing mutations in the GATA motif of the promoter region. A single nucleotide mutation in this motif resulted in constitutive ectopic expression of transgenic GFP in renal distal tubules, collecting ducts, and certain populations of epithelial cells in other tissues. Since both GATA-2 and GATA-3 bind to the GATA box in distal tubular cells, both factors are likely to repress constitutively ectopic Epo gene expression in these cells. Thus, GATA-based repression is essential for the inducible and cell type–specific expression of the Epo gene.


2011 ◽  
Vol 301 (3) ◽  
pp. F660-F671 ◽  
Author(s):  
Seetharamaiah Chittiprol ◽  
Phylip Chen ◽  
Danica Petrovic-Djergovic ◽  
Tad Eichler ◽  
Richard F. Ransom

The state-of-the-art cultured podocyte is conditionally immortalized by expression of a temperature-sensitive mutant of the SV40 large-T antigen. These cultures proliferate at 33°C and differentiate at 37°C into arborized cells that more closely resemble in vivo podocytes. However, the degree of resemblance remains controversial. In this study, several parameters were measured in podocyte cell lines derived from mouse (JR, KE), human (MS), and rat (HK). In all lines, the quantities of NEPH1 and podocin proteins and NEPH1 and SYNPO mRNAs were comparable to glomeruli, while synaptopodin and nephrin proteins and NPHS1 and NPHS2 mRNAs were <5% of glomerular levels. Expression of Wilms' tumor-1 (WT1) mRNA in mouse lines was comparable to glomeruli, but rat and human lines expressed little WT1. Undifferentiated human and mouse lines had similar proliferation rates that decreased after differentiation, while the rate in rat cells remained constant. The motility of different lines varied as measured by both general motility and wound-healing assays. The toxicity of puromycin aminonucleoside was MS ∼ JR >> KE, and of doxorubicin was JR ∼ KE > MS, while HK cells were almost unaffected. Process formation was largely a result of contractile action after formation of lamellipodia. These findings demonstrate dramatic differences in marker expression, response to toxins, and motility between lines of podocytes from different species and even between similarly-derived mouse lines.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ji-wen Cheng ◽  
Li-xia Duan ◽  
Yang Yu ◽  
Pu Wang ◽  
Jia-le Feng ◽  
...  

Abstract Background Mesenchymal stem cells (MSCs) play a crucial role in cancer development and tumor resistance to therapy in prostate cancer, but the influence of MSCs on the stemness potential of PCa cells by cell–cell contact remains unclear. In this study, we investigated the effect of direct contact of PCa cells with MSCs on the stemness of PCa and its mechanisms. Methods First, the flow cytometry, colony formation, and sphere formation were performed to determine the stemness of PCaMSCs, and the expression of stemness-related molecules (Sox2, Oct4, and Nanog) was investigated by western blot analysis. Then, we used western blot and qPCR to determine the activity levels of two candidate pathways and their downstream stemness-associated pathway. Finally, we verified the role of the significantly changed pathway by assessing the key factors in this pathway via in vitro and in vivo experiments. Results We established that MSCs promoted the stemness of PCa cells by cell–cell contact. We here established that the enhanced stemness of PCaMSCs was independent of the CCL5/CCR5 pathway. We also found that PCaMSCs up-regulated the expression of Notch signaling-related genes, and inhibition of Jagged1-Notch1 signaling in PCaMSCs cells significantly inhibited MSCs-induced stemness and tumorigenesis in vitro and in vivo. Conclusions Our results reveal a novel interaction between MSCs and PCa cells in promoting tumorigenesis through activation of the Jagged1/Notch1 pathway, providing a new therapeutic target for the treatment of PCa.


2006 ◽  
Vol 82 (6) ◽  
pp. 877-887 ◽  
Author(s):  
J. Sehm ◽  
H. Lindermayer ◽  
H. H. D. Meyer ◽  
M. W. Pfaffl

Flavan-3-ols are a class of flavonoids that are widely distributed in fruits and beverages including red wine and apples. Consumption of flavanoid-rich food has been shown to exhibit anti-microbial, anti-oxidative, anti-inflammatory, and immune-modulating effects. To test the nutritional effects of flavanols on mRNA gene-expression of inflammatory and apoptotic marker genes, piglets were given two flavanoids-rich feeding regimens: a low flavanoid standard diet (SD) was compared with diets enriched with 3·5% apple pomace (APD) or 3·5% red-wine pomace (RWPD). The influence on mRNA expression levels was investigated in different immunological active tissues and in the gastro-intestinal tract (GIT). The investigation took place from 1 week prior weaning to 19 days post weaning in 78 piglets. The expression of expressed marker genes was determinate by one-step quantitative real-time (qRT-PCR): TNFα, NFκB as pro-inflammatory; IL10, as anti-inflammatory; caspase 3 as apoptosis; cyclin D1 as cell cycle marker; and nucleosome component histon H3 as reference gene.The feeding regimens result in tissue individual regulation of mRNA gene expression in all investigated organs. It was discovered that there were significant differences between the applied diets and significant changes during feeding time curse. Both pomace treatments caused a significant up-regulation of all investigated genes in liver. The effect on mesenterial lymph nodes and spleen was not prominent. In the GIT, the treatment groups showed a inhibitory effects on gene expression mainly in stomach and jejunum (NFκB, cyclin D1 and caspase 3). In colon the trend of caspase 3 was positive with the greatest change in the RWPD group.In jejunum and stomach the cell cycle turn over was reduced, whereas in liver the cell turn over was highly accelerate. The influence on inflammatory marker gene expression is mainly relevant in stomach. It is presume that both flavanoid rich feeding regimens have the potential to modulate the mRNA expressions of inflammatory, proliferation and apoptotic marker genes in the GIT and piglet organs.


1997 ◽  
pp. 25-29 ◽  
Author(s):  
A. William Tank ◽  
Kristen M. Piech ◽  
Cheryl A. Osterhout ◽  
Baoyong Sun ◽  
Caronol Sterling

1996 ◽  
Vol 109 (5) ◽  
pp. 899-909 ◽  
Author(s):  
B. Capel ◽  
J.R. Hawkins ◽  
E. Hirst ◽  
D. Kioussis ◽  
R. Lovell-Badge

Cell cultures from the urogenital ridge have been established to facilitate the study of the regulation and downstream interactions of Sry in mammalian sex determination. Cells have been explanted from transgenic mice carrying a temperature sensitive SV40 large T-antigen, and established in ongoing cultures. Analysis of the cells in these cultures at the electron microscope level reveals multiple cell types that compare to the cell types found in vivo during this period of development. Primordial germ cells, that are simultaneously explanted in the course of these experiments, also survive in culture. The explants undergo a morphogenetic organization into branching cord-like structures when cells are trypsinized and plated in extracellular matrix (Matrigel). We analyzed the expression of a number of molecular markers of the fetal gonad during monolayer culture, during in vitro morphogenesis in Matrigel, and in clonal lines derived from the complex explants. This analysis included Sry which is found to be expressed in some cultures from XY urogenital ridges that have been maintained for as long as 8 months.


1996 ◽  
Vol 109 (5) ◽  
pp. 1009-1016
Author(s):  
S. Funamoto ◽  
H. Ochiai

The gp64 protein of Polysphondylium pallidum has been shown to mediate EDTA-stable cell-cell adhesion. To explore the functional role of gp64, we made an antisense RNA expression construct designed to prevent the gene expression of gp64; the construct was introduced into P. pallidum cells and the transformants were characterised. The antisense RNA-expressing clone L3mc2 which had just been harvested at the growth phase tended to re-form in aggregates smaller in size than did the parental cells in either the presence or absence of 10 mM EDTA. In contrast, 6.5-hour starved L3mc2 cells remained considerably dissociated from each other after 5 minutes gyrating, although aggregation gradually increased by 50% during a further 55 minutes gyrating in the presence of 10 mM EDTA. Correspondingly, L3mc2 lacked specifically the cell-cell adhesion protein, gp64. We therefore conclude that the gp64 protein is involved in forming the EDTA-resistant cell-cell contact. In spite of the absence of gp64, L3mc2 exhibited normal developmental processes, a fact which demonstrates that another cell-cell adhesion system exists in the development of Polysphondylium. This is the first report in which an antisense RNA technique was successfully applied to Polysphondylium.


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