Astrogliosis in culture. IV. Effects of basic fibroblast growth factor

Hou, Yang; Yu, Annie; Garcia, Johnny; Aotaki-Keen, A. E.; Lee, Y. L.; Eng, Lawrence F.; Hjelmeland, Leonard M.; Menon, V. K.

doi:10.1002/jnr.490400310

Cited by 62 publications

(54 citation statements)

References 41 publications

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“…Astrocytes infected with RCAS-bFGF, which induce proliferation and migration of glial cells in vivo also see Fig. 4, below), grew to slightly greater numbers than control astrocytes, as expected in view of the known mitogenic effects of bFGF on cultured astrocytes (Hou et al 1995) but did not survive significantly longer. In marked contrast, INK4a-ARF −/− astrocytes exhibited no loss of growth potential with passage and could be propagated indefinitely, consistent with the behavior of mouse embryo fibroblasts (MEFs) with lesions in this locus (Alcorta et al 1996;Nobel et al 1996) or in ARF alone (Kamijo et al 1997).…”

Section: Loss Of Ink4a-arf and Overexpression Of Cdk4 Both Immortalizsupporting

confidence: 66%

Modeling mutations in the G₁ arrest pathway in human gliomas: overexpression of CDK4 but not loss of INK4a–ARF induces hyperploidy in cultured mouse astrocytes

et al. 1998

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Nearly all human gliomas exhibit alterations in one of three genetic loci governing G 1 arrest: INK4a-ARF, CDK4, or RB. To discern the roles of CDK4 amplification and INK4a-ARF loss in gliomagenesis, we compared the behavior of astrocytes lacking a functional INK4a-ARF locus with astrocytes overexpressing CDK4. Either a deficiency of p16 INK4a and p19 ARF or an increase in Cdk4 allows cultured astrocytes to grow without senescence. Astrocytes overexpressing CDK4 grow more slowly than INK4a-ARF-deficient astrocytes and convert to a tetraploid state at high efficiency; in contrast, INK4a-ARF-deficient cells remain pseudodiploid, consistent with properties observed in human gliomas with corresponding lesions in these genes. Received July 20, 1998; revised version accepted October 14, 1998. Over half of high-grade human gliomas lack a functional INK4a-ARF locus (Jen et al. 1994;Schmidt et al. 1994) and hence can produce neither p16 INK4a nor p19 ARF , the two proteins encoded by this locus (Quelle et al. 1995). Most of the remaining gliomas either lack the RB gene or demonstrate a 10-to 100-fold amplification of the CDK4 locus (He et al. 1994(He et al. , 1995Ichimura et al. 1996). We are developing animal models for gliomagenesis in hopes of understanding these patterns and discerning the contributions made to tumor formation by each abnormality . We have taken advantage of two genetic alterations in mice: disruption of the INK4a-ARF locus by targeted mutation (Serrano et al. 1996) and astrocyte-specific expression of a transgene encoding TVA, the receptor for subgroup A avian leukosis viruses (ALV) (Holland and Varmus 1998). Production of TVA molecules by these cells makes them susceptible to infection by RCAS vectors carrying coding domains for CDK4 and other genes .We have used this gene transfer system to investigate the effects of INK4a-ARF loss and CDK4 overexpression in astrocyte cell culture and to determine whether similarities exist between the cultured cells and human gliomas with similar abnormalities. Results and Discussion Loss of INK4a-ARF and overexpression of CDK4 both immortalize astrocyte culturesTo compare the growth properties of INK4a-ARF-deficient and CDK4-overexpressing astrocytes, we subjected appropriately selected cultures to repeated passage at standard density and counted the number of cells at each passage. Astrocytes overexpressing CDK4 were prepared by infecting primary brain cultures from Gtv-a mice [carrying a tv-a transgene under the control of the astrocytespecific glial fibrillary acidic protein (GFAP) promoter] with an RCAS vector carrying the human CDK4 cDNA (RCAS-cdk4). Cultures of INK4a-ARF-deficient astrocytes were prepared by infecting primary brain cell cultures from Gtv-a transgenic; INK4a-ARF −/− mice with an RCAS vector bearing the puro-R gene (RCAS-puro) ) and selecting for resistance to puromycin. Parallel cultures were prepared by infecting brain cells from Gtv-a transgenic mice with RCAS vectors carrying the alkaline phosphatase (AP) or the basic fibroblast grow...

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Section: Loss Of Ink4a-arf and Overexpression Of Cdk4 Both Immortalizsupporting

confidence: 66%

Modeling mutations in the G₁ arrest pathway in human gliomas: overexpression of CDK4 but not loss of INK4a–ARF induces hyperploidy in cultured mouse astrocytes

et al. 1998

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“…1C,D), cell proliferation (Fig. 3C,D), and responsiveness to basic fibroblast growth factor (Yu et al, 1993;Hou et al, 1995).…”

Section: Resultsmentioning

confidence: 93%

“…Our studies were facilitated by the development of an in vitro scar model (Yu et al, 1993), resembling reactive gliosis in many respects (Yu et al, 1993;Hou et al, 1995). In this in vitro model, astrocytes show upregulation of both mitotic activity and glial fibrillary acidic protein (GFAP) expression, comparable to that seen in vivo (Bignami and Dahl, 1976;Armaducci, 1981;Aquino, 1988).…”

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confidence: 98%

Electrophysiological Changes That Accompany Reactive GliosisIn Vitro

1997

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An in vitro injury model was used to examine the electrophysiological changes that accompany reactive gliosis. Mechanical scarring of confluent spinal cord astrocytes led to a threefold increase in the proliferation of scar-associated astrocytes, as judged by bromodeoxyuridine (BrdU) labeling. Whole-cell patch-clamp recordings demonstrated that current profiles differed absolutely between nonproliferating (BrdU Ϫ ) and proliferating (BrdU ϩ ) astrocytes. The predominant current type expressed in BrdU Ϫ cells was an inwardly rectifying K ϩ current (K IR ; 1.3 pS/pF). BrdU Ϫ cells also expressed transient outward K ϩ currents, accounting for less than one-third of total K ϩ conductance (G). In contrast, proliferating BrdU ϩ astrocytes exhibited a dramatic, approximately threefold reduction in K IR (0.45 pS/pF) but showed a twofold increase in the conductance of both transient (K A ) (0.67-1.32 pS/pF) and sustained (K D ) (0.42-1.10 pS/pF) outwardly rectifying K ϩ currents, with a G KIR : G KD ratio of 0.4. Relative expression of G KIR :G KD led to more negative resting potentials in nonproliferating (Ϫ60 mV) versus proliferating astrocytes (Ϫ53 mV; p ϭ 0.015). Although 45% of the nonproliferating astrocytes expressed Na ϩ currents (0.47 pS/pF), the majority of proliferating cells expressed prominent Na ϩ currents (0.94 pS/pF). Injury-induced electrophysiological changes are rapid and transient, appearing within 4 hr postinjury and, with the exception of K IR , returning to control conductances within 24 hr. These differences between proliferating and nonproliferating astrocytes are reminiscent of electrophysiological changes observed during gliogenesis, suggesting that astrocytes undergoing secondary, injury-induced proliferation recapitulate the properties of immature glial cells. The switch in predominance from K IR to K D appears to be essential for proliferation and scar repair, because both processes were inhibited by blockade of K D .

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“…bFGF has been shown to be a mitogen for astrocytes and to cause migration of both astrocytes and glioma cells in culture (23)(24)(25). Furthermore, the Drosophila gene breathless, encod- ing an FGF receptor homolog, has been shown to be essential for migration of midline glial cells (26) and glial progenitor cells expressing a dominant-negative FGF receptor fail to migrate when transplanted into neonatal rat brains (30).…”

Section: Discussionmentioning

confidence: 99%

Basic fibroblast growth factor induces cell migration and proliferation after glia-specific gene transfer in mice

Holland

Varmus

1998

Proc. Natl. Acad. Sci. U.S.A.

271

194

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Basic fibroblast growth factor (bFGF) is overexpressed in most high-grade human gliomas, implying that it is involved in the pathogenesis of these tumors. To assess the biological effect of inappropriate production of bFGF in normal astrocytes, we developed a system for gliaspecific gene transfer in transgenic mice. A transgene encoding the receptor for subgroup A avian leukosis virus and controlled by the astrocyte-specific glial fibrillary acidic protein promoter permits efficient glia-specific transfer of genes carried by subgroup A avian leukosis virus vectors. With this system, we have demonstrated that bFGF induces proliferation and migration of glial cells in vivo, without the induction of tumors.

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Astrogliosis in culture. IV. Effects of basic fibroblast growth factor

Cited by 62 publications

References 41 publications

Modeling mutations in the G₁ arrest pathway in human gliomas: overexpression of CDK4 but not loss of INK4a–ARF induces hyperploidy in cultured mouse astrocytes

Modeling mutations in the G₁ arrest pathway in human gliomas: overexpression of CDK4 but not loss of INK4a–ARF induces hyperploidy in cultured mouse astrocytes

Electrophysiological Changes That Accompany Reactive GliosisIn Vitro

Basic fibroblast growth factor induces cell migration and proliferation after glia-specific gene transfer in mice

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Astrogliosis in culture. IV. Effects of basic fibroblast growth factor

Cited by 62 publications

References 41 publications

Modeling mutations in the G1 arrest pathway in human gliomas: overexpression of CDK4 but not loss of INK4a–ARF induces hyperploidy in cultured mouse astrocytes

Modeling mutations in the G1 arrest pathway in human gliomas: overexpression of CDK4 but not loss of INK4a–ARF induces hyperploidy in cultured mouse astrocytes

Electrophysiological Changes That Accompany Reactive GliosisIn Vitro

Basic fibroblast growth factor induces cell migration and proliferation after glia-specific gene transfer in mice

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Modeling mutations in the G₁ arrest pathway in human gliomas: overexpression of CDK4 but not loss of INK4a–ARF induces hyperploidy in cultured mouse astrocytes

Modeling mutations in the G₁ arrest pathway in human gliomas: overexpression of CDK4 but not loss of INK4a–ARF induces hyperploidy in cultured mouse astrocytes