scholarly journals Conditionally Immortalized Cell Lines as a New In Vitro Model for the Study of Barrier Functions

2001 ◽  
Vol 24 (2) ◽  
pp. 111-118 ◽  
Author(s):  
Tetsuya TERASAKI ◽  
Ken-ichi HOSOYA
2005 ◽  
Vol 288 (3) ◽  
pp. L536-L545 ◽  
Author(s):  
Jackeline Agorreta ◽  
Javier J. Zulueta ◽  
Luis M. Montuenga ◽  
Mercedes Garayoa

Adrenomedullin (ADM) is upregulated independently by hypoxia and LPS, two key factors in the pathogenesis of acute lung injury (ALI). This study evaluates the expression of ADM in ALI using experimental models combining both stimuli: an in vivo model of rats treated with LPS and acute normobaric hypoxia (9% O2) and an in vitro model of rat lung cell lines cultured with LPS and exposed to hypoxia (1% O2). ADM expression was analyzed by in situ hybridization, Northern blot, Western blot, and RIA analyses. In the rat lung, combination of hypoxia and LPS treatments overcomes ADM induction occurring after each treatment alone. With in situ techniques, the synergistic effect of both stimuli mainly correlates with ADM expression in inflammatory cells within blood vessels and, to a lesser extent, to cells in the lung parenchyma and bronchiolar epithelial cells. In the in vitro model, hypoxia and hypoxia + LPS treatments caused a similar strong induction of ADM expression and secretion in epithelial and endothelial cell lines. In alveolar macrophages, however, LPS-induced ADM expression and secretion were further increased by the concomitant exposure to hypoxia, thus paralleling the in vivo response. In conclusion, ADM expression is highly induced in a variety of key lung cell types in this rat model of ALI by combination of hypoxia and LPS, suggesting an essential role for this mediator in this syndrome.


2001 ◽  
Vol 69 (5) ◽  
pp. 3110-3119 ◽  
Author(s):  
Robert Barthel ◽  
Jianwei Feng ◽  
Jorge A. Piedrahita ◽  
David N. McMurray ◽  
Joe W. Templeton ◽  
...  

ABSTRACT Genetically based natural resistance to brucellosis in cattle provides for novel strategies to control zoonotic diseases. BovineNRAMP1, the homologue of a murine gene (Bcg), has been identified as a major candidate for controlling the in vivo resistant phenotype. We developed an in vitro model for expression of resistance- and susceptibility-associated alleles of bovine NRAMP1 as stable transgenes under the regulatory control of the bovineNRAMP1 promoter in the murine RAW264.7 macrophage cell line (Bcg s ) to analyze the regulation of the NRAMP1 gene and its role in macrophage function. We demonstrated that the 5′-flanking region of bovineNRAMP1, despite the lack of TATA and CAAT boxes, has a functional promoter capable of driving the expression of a transgene in murine macrophages. A polymorphism within a microsatellite in the 3′ untranslated region critically affects the expression of bovineNRAMP1 and the control of in vitro replication ofBrucella abortus but not Salmonella enterica serovar Dublin. We did not observe any differences in the production of NO by resting or gamma interferon (IFN-γ)- and IFN-γ–lipopolysaccharide (LPS)-treated transfected cell lines, yet the resistant transfected cell lines produced significantly less NO than other cell lines, following stimulation with LPS at 24 and 48 h.


2005 ◽  
Vol 102 (1) ◽  
pp. 98-108 ◽  
Author(s):  
Todd M. Savarese ◽  
Taichang Jang ◽  
Hoi Pang Low ◽  
Rebecca Salmonsen ◽  
N. Scott Litofsky ◽  
...  

Object. Brain tumors, including gliomas, develop several months after rats are exposed in utero to N-ethyl-N-nitrosourea (ENU). Although pathological changes cannot be detected until these animals are several weeks old, the process that eventually leads to glioma formation must begin soon after exposure given the rapid clearance of the carcinogen and the observation that transformation of brain cells isolated soon after exposure occasionally occurs. This model can therefore potentially provide useful insights about the early events that precede overt glioma formation. The authors hypothesized that future glioma cells arise from stem/progenitor cells residing in or near the subventricular zone (SVZ) of the brain. Methods. Cells obtained from the SVZ or corpus striatum in ENU-exposed and control rats were cultured in an epidermal growth factor (EGF)-containing, chemically defined medium. Usually, rat SVZ cells cultured in this manner (neurospheres) are nestin-positive, undifferentiated, and EGF-dependent and undergo cell senescence. Consistent with these prior observations, control SVZ cells undergo senescence by the 12th to 15th doubling (20 of 20 cultures). In contrast, three of 15 cultures of cells derived from the SVZs of individual ENU-treated rats continue to proliferate for more than 60 cell passages. Each of these nestin-expressing immortalized cell lines harbored a common homozygous deletion spanning the INK4a/ARF locus and was unable to differentiate into neural lineages after exposure to specific in vitro stimuli. Nevertheless, unlike the rat C6 glioma cell line, these immortalized cell lines demonstrate EGF dependence and low clonogenicity in soft agar and did not form tumors after intracranial transplantation. Conclusions. Data in this study indicated that immortalized cells may represent glioma precursors that reside in the area of the SVZ after ENU exposure that may serve as a reservoir for further genetic and epigenetic hits that could eventually result in a full glioma phenotype.


Sign in / Sign up

Export Citation Format

Share Document