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U I Heine

Publications and source records attributed to U I Heine.

At least 19 recordsLinked to original sources
PubMed1991

Localization of transforming growth factor-beta 1 in mitochondria of murine heart and liver.

Using both electron microscopic immunohistochemistry and cell fractionation techniques, we show that transforming growth factor-beta 1 (TGF-beta 1) is found in mitochondria of rat and mouse cardiac myocytes and rat hepatocytes. Four different polyclonal antibodies, raised against various epitopes encompassing the mature portion of the TGF-beta 1 molecule as well as the pro-region of its precursor, were used for the electron microscopy studies. The localization of TGF-beta 1 in mitochondria was confirmed by detection of the native peptide in mitochondria isolated from rat heart and liver; the majority of native TGF-beta 1 found in liver homogenates was recovered in highly pure mitochondrial fractions. The functional role of TGF-beta in the mitochondrion is unknown at present.

Animals↗
PubMed1990

Effect of 12-O-tetradecanoylphorbol-13-acetate on colony formation and intercellular communication in a coculture system of JB6 clones.

Disruption of intercellular communication (IC) by tumor promoters has been implicated as one of the major events in the promotion process. We studied the effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) on IC in relation to colony formation (CF) in a coculture system of mouse epidermal JB6 cells, including unpromotable, promotable, and transformed clones. CF was evaluated in cocultures where cells were overlaid onto irradiated mat cells. IC was evaluated by the dye transfer assay in cocultures where overlaid cells were labeled with fluorescent beads. Enhancement of CF by TPA was observed in combinations where promotable clones were used as overlays. However, suppression of IC by TPA was observed in all clones of overlaid cells (day 1) and did not correlate satisfactorily to subsequent CF. Growth-arrested cells retained their capability to communicate with mat cells, while IC between colony-forming cells and mat cells was disrupted during CF (day 5), implying that selective communication is an event secondary to CF. It is suggested that in our experimental model, short-term suppression of IC by TPA may not be sufficient to explain subsequent colony formation and that other factors should be considered.

Animals↗
PubMed1990

Transforming growth factor-beta: multifunctional regulator of differentiation and development.

Transforming growth factors-beta (TGF-beta) are 25 kilodalton (kDa) homodimeric peptides with multifunctional actions controlling the growth, differentiation and function of a broad range of target cells of both epithelial and mesenchymal derivation. They are expressed early in embryogenesis and their tissue-specific and developmentally dependent expression is strongly suggestive of an essential role in particular morphogenetic and histogenetic events. Five distinct TGF-beta s have been characterized so far, with 65-80% homology to each other. By using both molecular biological and immunohistochemical techniques, we are currently attempting to define specific sites of expression of the different TGF-beta s and to determine whether TGF-beta s 1-5 might have unique functions in development and in the mature organism. Comparative study of the promoter regions for the different TGF-beta s and for any particular TGF-beta in different species is also underway. Mechanistically, TGF-beta s act to control gene expression of their target cells, many of their actions converging on a complex, multifaceted scheme of control of matrix proteins and their interactions with cells; these effects on matrix are thought to mediate many of the effects of TGF-beta on development.

Amino Acid Sequence↗
PubMed1990

Effect of 12-O-tetradecanoylphorbol-13-acetate on intercellular communication in various clones of mouse epidermal JB6 cells.

We studied gap junctional intercellular communication (IC) in various clones of mouse epidermal JB6 cells and the effect of the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA) on such communication. JB6 clones used included nonpromotable, promotable, and transformed clones, representing a spectrum in susceptibility to transformation from nontransformed, to initiated (postinitiated), to transformed cells. We used the dye transfer assay and the radioisotope transfer assay, and quantified IC both in homologous pairings, where IC among cells of a single clone was examined, and heterologous pairings, where cells of initiated or transformed clones were paired with cells of a nonpromotable clone. Both pairings showed good IC in the absence of TPA and poor IC in the presence of TPA. However, suppression of IC by TPA was more effective when cells had advanced in promotability. IC was more suppressed by TPA in heterologous pairing than in homologous pairing. These results implied that in advanced stages of promotion, the capability to retain IC with each other (homologous IC) and especially with their nontransformed counterpart (heterologous IC) is progressively lost. Thus we conclude that the interaction of initiated cells and transformed cells with nontransformed cells decreases progressively in this model system for tumor promotion and progression.

Animals↗
PubMed1990

Colocalization of TGF-beta 1 and collagen I and III, fibronectin and glycosaminoglycans during lung branching morphogenesis.

The possible in vivo role of TGF-beta 1 in regulating various proteins of the extracellular matrix, including fibronectin, collagen I and III, and glycosaminoglycans, was examined by immunohistochemical methods during critical stages of lung morphogenesis in the 11- to 18-day-old mouse embryo. Sections of Bouin-fixed, paraffin-embedded whole embryos were exposed to polyclonal antibodies specific to synthetic peptides present in the precursor part of TGF-beta 1 (pro-TGF-beta 1), in the processed TGF-beta 1 (antibody CC), collagen I and III, fibronectin, followed by the PAP or ABC technique to visualize the location of the antibody. GAG were stained with Alcian Blue 8GX. Our results indicate colocalization of TGF-beta 1 expression and that of matrix proteins in the developing lung when branching morphogenesis (cleft formation) and tissue stabilization occur. The presence of TGF-beta 1 at the epithelial-mesenchymal interfaces of stalks and clefts at a time when matrix proteins can first be visualized in these areas, suggests a direct participation of the growth factor in the development of the basic architecture of the lung.

Animals↗
PubMed1990

Transforming growth factor-beta 1 specifically localizes in elastin during synovial inflammation: an immunoelectron microscopic study.

We report here that extracellular TGF-beta 1 is associated exclusively with microfibrils of elastin which are present in the extracellular matrix of the inflamed articular joint of the rat. Inflammation was initiated by bacterial cell walls localized in the synovium following intraperitoneal injection of the bacterial components. This synovitis is associated with both destruction of connective tissue components and matrix deposition. The growth factor was localized by using a polyclonal antibody raised to a synthetic peptide corresponding to amino terminal 30 amino acids of TGF-beta 1 in conjunction with a gold-labeled secondary antibody. The results suggest a close association of TGF-beta 1 with proteoglycans which are known to be a major component of the microfibrils in elastin. Proteoglycan-mediated binding and concentration of TGF-beta 1 in specific areas of the extracellular matrix may constitute a mechanism whereby the growth factor could be targeted to specific sites of action.

Animals↗
PubMed1987

Effect of adhesion factors fibronectin, laminin, and type IV collagen on spreading and growth of transformed and control rat liver epithelial cells.

To examine the specific effects of individual basement membrane components on the behavior of transformed cells of epithelial origin, ethionine-transformed cells and control cells at low and high passage levels were seeded on glass that had been coated with fibronectin, laminin, or type IV collagen. The cells used were sublines of the liver-derived TRL 1215 epithelial cell line, a line in which transformation has been shown to be accompanied by increased cell-substrate adhesion and cell spreading. Cell spreading on the different basement membrane components was determined by morphometry, and growth (proliferation) was measured by protein and DNA analyses. Laminin increased spreading and growth in transformed and control sublines. Laminin also induced changes in cell shape that were indicative of increased cell motility. For the control cells, fibronectin and also type IV collagen were less effective than laminin in stimulating cell spreading and growth. However, for the ethionine-transformed cells, fibronectin was as effective as laminin in stimulating cell spreading. With the exception of the spreading response to fibronectin, the ethionine-transformed cells were less sensitive to the defined substrata than were the control sublines. Moreover, only the ethionine-transformed cells were able to proliferate in serum-free medium. Thus, greater autonomy is characteristic of transformation for these epithelial cells and is exemplified by the reduced influence of and dependence on exogenous factors, both substrate-bound and soluble, for spreading and growth.

Animals↗
PubMed1987

Inhibition of intercellular communication by nickel(II): antagonistic effect of magnesium.

The level of gap-junctional (cell-cell) communication was studied by the radioisotope transfer technique in NIH 3T3 cells exposed to NiSO4, MgSO4, or both salts combined. Monolayered NIH 3T3 donor cells were labeled with [3H]-uridine for 3 h and then co-cultured with non-labeled recipient NIH 3T3 cells for 3 h in the presence of 0.5-20 mM NiSO4, 1.0-100 mM MgSO4, or 5 mM NiSO4 plus 1.0-100 mM MgSO4. 12-O-tetradecanoylphorbol-13-acetate (TPA), 16-160 pM, served as a positive control. The exposed cells were fixed with 2.5% glutaraldehyde and processed for autoradiography. The cell-cell communication rate was based on the number of radioactive recipient cells in relation to the total number of recipient cells for 100 donor cells. NiSO4 disrupted cell-cell communication in a dose-related manner from 98% of the base value at 0.5 mM NiSO4 to 2% at 5 mM NiSO4. Cell viability was not affected by 0.5-5 mM NiSO4. The inhibitory action of 5 mM NiSO4 could be partially prevented by 5.0-100 mM MgSO4. However, MgSO4 did not prevent the inhibition by TPA. The results indicate that NiSO4 is capable of inhibiting cell-cell communication at concentrations that do not cause cytotoxic effects in NIH 3T3 cells during a 3-h period. In this respect NiSO4 resembles such classical tumor promoters like TPA. The antagonism by magnesium of the nickel-induced inhibition of cell-cell communication may indicate a contributory mechanism by which magnesium counteracts the carcinogenicity of nickel in vivo.

Cell Communication↗
PubMed1986

Transforming growth factor type beta: rapid induction of fibrosis and angiogenesis in vivo and stimulation of collagen formation in vitro.

Transforming growth factor type beta (TGF-beta), when injected subcutaneously in newborn mice, causes formation of granulation tissue (induction of angiogenesis and activation of fibroblasts to produce collagen) at the site of injection. These effects occur within 2-3 days at dose levels than 1 microgram. Parallel in vitro studies show that TGF-beta causes marked increase of either proline or leucine incorporation into collagen in either an NRK rat fibroblast cell line or early passage human dermal fibroblasts. Epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) do not cause these same in vivo and in vitro effects; in both rat and human fibroblast cultures, EGF antagonizes the effects of TGF-beta on collagen formation. We have obtained further data to support a role for TGF-beta as an intrinsic mediator of collagen formation: conditioned media obtained from activated human tonsillar T lymphocytes contain greatly elevated levels of TGF-beta compared to media obtained from unactivated lymphocytes. These activated media markedly stimulate proline incorporation into collagen in NRK cells; this effect is blocked by a specific antibody to TGF-beta. The data are all compatible with the hypothesis that TGF-beta is an important mediator of tissue repair.

Amino Acids↗
PubMed1986

Role of cytoskeleton changes and expression of the H-ras oncogene during promotion of neoplastic transformation in mouse epidermal JB6 cells.

The relationship between cytoskeletal changes and oncogene expression in initiated cells during exposure to a tumor promoter was investigated in the phorbol ester-sensitive murine epidermis-derived cell line JB6 (P+ cells) and its promotion-insensitive variant (P- cells) using immunocytochemical methods, soft agar assays, and tumorigenicity tests in nude mice. Cytoskeletal changes in P+ and P- cells induced by short-term incubation with 12-O-tetradecanoylphorbol-13-acetate (TPA) were similar. Prolonged incubation with TPA allowed P- cells to regain their original appearance and resulted in growth inhibition; however, the extended presence of TPA produced in P+ cells persistent alterations in the distribution of actin, vinculin, and fibronectin. P+ cells proceeded to develop multilayered foci. Using monoclonal antibodies, we detected the H-ras oncogene-encoded Mr 21,000 protein (p21) exclusively in focus-forming cells. Both the observed morphological changes and the expression of p21 were reversible in P+ cells when TPA exposure was terminated soon after foci had developed. In order for TPA-treated P+ cells to grow as tumors in nude mice, multiple cycles of exposure to TPA in conjunction with clonal expansion in agar were necessary. The results indicate that there exists during promotion of the P+ JB6 cells a relationship between expression of the H-ras gene product p21 and enhanced proliferation with focus formation and that both expression of p21 and focus formation depend on the continuous presence of the promoting agent.

Actin Cytoskeleton↗
PubMed1985

Effects of retinoid deficiency on the development of the heart and vascular system of the quail embryo.

The regulatory role of retinoids in growth and differentiation has been examined in vitro and in vivo by light and scanning electron microscopy using retinoid-deficient and control quail embryos between the 5-15 somite stage, as well as 2- and 2.5-day-old embryos. Fertile, retinoid-deficient eggs were obtained from flocks of quail maintained on a retinoid- and carotenoid-deficient diet, supplemented only with small amounts of retinoic acid methyl ester as described by Thompson et al. 1969. As described previously, retinoid deprivation during embryonal development causes abnormalities in organs of epithelial and mesenchymal origin, most dramatically preventing the formation of the extraembryonal circulatory system in the avian embryo. Our in vivo studies show that the basis for the latter defect is the failure of the primitive heart tubes to open at their posterior end, thus preventing the formation of omphalomesenteric veins normally connecting the embryonal with the extraembryonal circulatory system. Early manifestation of the retinoid-deficient defect may result also in formation of a cardia bifida, late manifestation in development of a single dilated ventricle. In contrast, the extraembryonal vascular system of blood islands is well developed. Heart function as shown by the rate of heart beat is reduced in deficient embryos. Our in vitro studies demonstrate similar defects in the development of the circulatory system by culture of normal 24-h embryos on retinoid-deficient agar medium; conversely, normal development is observed upon culture of retinoid-deficient embryos on retinoid-containing agar medium.

Animals↗
PubMed1985

Intracellular type A retrovirus movement associated with an intact microtubule system.

Intracytoplasmic type A particles known to be precursors to type B retroviruses in murine, hamster and marsupial cells are closely associated with microtubules and microtubule organizing centres. In this publication, the active participation of microtubules in the intracellular transport of the particles to the cell surface has been examined in NIH 3T3 cells infected with M432 virus using vincristine sulphate (VCR) as inhibitor of microtubule polymerization. The release of virus at different times after exposure to VCR was quantified by reverse transcriptase determinations of cell supernatants and by electron microscopic quantification of the number of virions at the cell surface using freeze-dried whole cell replicas. These studies indicate that VCR inhibits both microtubule polymerization and virus release, and thus suggest that intact cytoplasmic microtubules are necessary for intracellular transport and release of virus.

Animals↗
PubMed1985

Transformation-associated increase of adhesion, cellular fibronectin, and stress fiber development in a liver epithelial cell line.

Cytoskeletal and adhesion characteristics of DL-ethionine (CAS: 67-21-0)-transformed rat liver epithelial cells (ETC) were compared with those of nontumorigenic, untreated cells of the same cell line both at the same passage level as ETC and at an early low passage level. ETC and high-passage-level cells (HPC) showed increased cell spreading and prominent actin stress fibers compared to low-passage-level cells (LPC). The number of adhesion plaques per unit cell area was higher for ETC than for LPC. At confluence, fibronectin expression was high for ETC, moderate for HPC, and low for LPC. The observed increases in cell spreading and in actin and fibronectin expression appeared to be associated with transformation of this cell line rather than being specific responses to ethionine treatment. This conclusion is suggested by the fact that HPC, which display preneoplastic markers, are similar in many respects to ETC.

Actins↗
PubMed1984

Characterization of rat liver cells transformed in culture by DL-ethionine.

A rat liver-derived epithelial cell line transformed with DL-ethionine and the corresponding control cell line were characterized according to morphological and cytochemical criteria to establish their origin from liver epithelium and to identify cellular changes due to transformation by DL-ethionine. The presence of intermediate junctions confirms the epithelial nature; glycogen accumulation and glucose-6-phosphatase activity confirm the hepatic origin of the cells. Persistent alterations resulting from ethionine transformation were variations in cell shape and size, focal multilayered growth, an increase in the nucleolar:nuclear ratio, and a reduction in the number of cells displaying a primary cilium. Hyperplasia of the inner nuclear membrane, elongation and branching of mitochondria, and a reduction in the length and frequency of cell junctions were also characteristic of the transformed cells.

Animals↗
PubMed1983

Quantitative light and electron microscopic changes in thymic reticular epithelial cells during Moloney-virus-induced lymphoma development.

This report describes two types of reticular epithelial cell in the thymic cortex of the BALB/c mouse, an immature and a mature form. During early stages of lymphoma development, i.e., 2-6 weeks postinfection (p.i.) with Moloney leukemia virus (M-MuLV), activation of the epithelial cells is observed. Although the percentage of these cells in the total cell population of the thymic cortex remains constant during that time, the number of mature epithelial cells is significantly increased in infected animals. Subsequently, about 6 weeks p.i., the number of immature epithelial cells starts to increase, whereas the number of mature reticular epithelial cells declines and the appearance of the mature epithelial cells changes drastically. The results of light and electron microscopic studies indicate degeneration of the mature reticular epithelial cells at the onset of lymphoma development at a time when the first deficiencies in the immunologic competence of the reticular epithelial cells are apparent.

Animals↗
PubMed1983

Differentiation block of prethymic lymphocytes during Moloney-virus-induced lymphoma development associated with a thymic epithelial defect.

Previous cytokinetic studies in Moloney-virus (M-MuLV)-induced lymphomas of BALB/c mice showed an intrathymic maturation block of prethymic lymphocytes derived from hematopoietic tissues. Thymus-cell cultures during the latent period of lymphoma development showed a proportion of nonlymphoid cells (NLC) from uninfected mice of 0.1% (3 days) to 0.002% (20 days), rising in infected mice to 1-2% after 5 weeks. Concomitantly, thymic epithelial cells exhibit progressive degenerative changes in vivo in infected mice with virus replication and in vitro a marked cellular polymorphism with nuclear atypia becomes overt. Immunofluorescence studies of thymopoietin II and serum thymus factor in epithelial cells indicate a marked decrease of these hormones in the epithelial cells from infected mice. These results suggest a functional defect of virus-infected thymic epithelial cells which causes a progressive accumulation of nondifferentiating T-cell precursors.

Animals↗