FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2039786301> ?p ?o ?g. }

• W2039786301 endingPage "291" @default.
• W2039786301 startingPage "286" @default.
• W2039786301 abstract "Nitric oxide (NO) is known to exert cytotoxic and cytostatic effects in various cells and tissues. Although NO formation in human skin has been convincingly demonstrated, little is known about the NO-mediated effects in skin physiology and pathology. Here, we investigate the influence of NO on proliferation, differentiation, and apoptosis of primary cultures of normal human keratinocytes and fibroblasts. Four different NO donors at concentrations ranging from 0.01 to 5 mM were added every 12 h or 24 h to primary cultures of human keratinocytes and fibroblasts, and cells cultured for up to 3 d in the presence of these compounds. Cultures were examined for necrosis or apoptosis using trypan blue exclusion and in situ nick-translation. Cultures were also screened for the expression of the proliferation marker Ki67 and for an increase in cell numbers using neutral red staining. In addition, keratinocytes were stained for cytokeratin 6 expression to assess differentiation. We find that both keratinocytes and fibroblasts are highly resistant towards necrosis- or apoptosis-inducing effects of NO. In both cell types NO modulates cell growth, albeit in a cell-type specific pattern: cytostasis becomes significant in fibroblasts at concentrations of ≥ 0.25 mM of the NO donor. In keratinocytes a biphasic effect is found with increased proliferation at low concentrations ranging from 0.01 to 0.25 mM and cytostasis at concentrations of ≥ 0.5 mM. Conversely, expression of cytokeratin 6 is decreased at the lower NO donor concentrations and increased at higher concentrations as an indication of induction of differentiation at higher NO concentrations. Collectively, our results demonstrate that NO modulates proliferation and differentiation in human skin cells, a finding that will help to explain the pathophysiology of human skin diseases. Moreover, these findings suggest that NO generation in human skin diseases is not directly associated with local cell destruction, in contrast to findings in several other human diseases. Nitric oxide (NO) is known to exert cytotoxic and cytostatic effects in various cells and tissues. Although NO formation in human skin has been convincingly demonstrated, little is known about the NO-mediated effects in skin physiology and pathology. Here, we investigate the influence of NO on proliferation, differentiation, and apoptosis of primary cultures of normal human keratinocytes and fibroblasts. Four different NO donors at concentrations ranging from 0.01 to 5 mM were added every 12 h or 24 h to primary cultures of human keratinocytes and fibroblasts, and cells cultured for up to 3 d in the presence of these compounds. Cultures were examined for necrosis or apoptosis using trypan blue exclusion and in situ nick-translation. Cultures were also screened for the expression of the proliferation marker Ki67 and for an increase in cell numbers using neutral red staining. In addition, keratinocytes were stained for cytokeratin 6 expression to assess differentiation. We find that both keratinocytes and fibroblasts are highly resistant towards necrosis- or apoptosis-inducing effects of NO. In both cell types NO modulates cell growth, albeit in a cell-type specific pattern: cytostasis becomes significant in fibroblasts at concentrations of ≥ 0.25 mM of the NO donor. In keratinocytes a biphasic effect is found with increased proliferation at low concentrations ranging from 0.01 to 0.25 mM and cytostasis at concentrations of ≥ 0.5 mM. Conversely, expression of cytokeratin 6 is decreased at the lower NO donor concentrations and increased at higher concentrations as an indication of induction of differentiation at higher NO concentrations. Collectively, our results demonstrate that NO modulates proliferation and differentiation in human skin cells, a finding that will help to explain the pathophysiology of human skin diseases. Moreover, these findings suggest that NO generation in human skin diseases is not directly associated with local cell destruction, in contrast to findings in several other human diseases. nitric oxide nitric oxide synthase nitroprusside Nitric oxide (NO) is known to act cytostatic and cytotoxic in various cells and tissues. NO is produced by an enzyme family of nitric oxide synthases (NOS) consisting of three isoforms, the neuronal constitutive (ncNOS), the endothelial constitutive (ecNOS), and the inducible isoform (iNOS) (Kröncke et al., 1995aKröncke K.D. Fehsel K. Sommer A. Rodriguez M.L. Kolb-bachofen V. Nitric oxide generation during cellular metabolization of the diabetogenic N-methyl-N-nitroso-urea streptozotozin contributes to islet cell DNA damage.Biol Chem Hoppe-Seyler. 1995 a; 376: 179-185Crossref PubMed Scopus (160) Google Scholar). Expression of both the constitutive as well as the inducible isoform has been shown in several cells resident to the skin, including keratinocytes and fibroblasts (Bruch-gerharz et al., 1996Bruch-gerharz D. Fehsel K. Suschek C. Michel G. Ruzicka T. Kolb-bachofen V. A proinflammatory activity of interleukin 8 in human skin: Expression of the inducible nitric oxide synthase in psoriatic lesions and cultured keratinocytes.J Exp Med. 1996; 184: 1-7Crossref Scopus (155) Google Scholar,Bruch-gerharz et al., 1998Bruch-gerharz D. Ruzicka T. Kolb-bachofen V. Nitric oxide in human skin: Current status and future prospects.J Invest Dermatol. 1998; 110: 1-7Abstract Full Text Full Text PDF PubMed Scopus (185) Google Scholar[BC1];Du et al., 1997Du M. Islam M. Ohmura Y. Moriyama Y. Fujimura S. Promotion of proliferation of murine BALB/c3T3 fibroblasts mediated by nitric oxide at lower concentrations.Biochem Mol Biol Int. 1997; 41: 625-631PubMed Google Scholar). To examine the effects of NO on cell proliferation, differentiation, and apoptosis in keratinocytes and fibroblasts, cells were incubated in the presence of four different NO donors and examined for proliferation or differentiation by immunostaining with the Ki67 antigen or cytokeratin 6. Furthermore, NO-mediated apoptotic or necrotic effects were investigated using in situ nick-translation or trypan blue exclusion. Altered states of proliferation and differentiation are known to play an important role in various hyperproliferative diseases such as psoriasis. In the case of human skin diseases associated with epidermal hyperproliferation, several different morphologic and biochemical alterations have been observed. For instance, induction of cytokeratins 6 (K6) and 16 (K16) combined with the reduction of cytokeratins 1 (K1) and 10 (K10) are significant differences to normal epidermis (Weiss et al., 1984Weiss R.A. Eichner R. Sun T.T. Monoclonal antibody analysis of keratin expression in epidermal diseases: A 48- and 56- kdalton keratin as molecular markers for hyperproliferative keratinocytes.J Cell Biol. 1984; 98: 1397-1406Crossref PubMed Scopus (435) Google Scholar;McGuire et al., 1984McGuire J. Ocber M. Lightfoot L. Two keratins MW 50,000 and 56, 000 are synthesized by psoriatic epidermis.Br J Dermatol. 1984; 27: 27-37Crossref Scopus (28) Google Scholar). Thus, in normal human epidermis as well as during wound healing processes K6 and K16 are expressed transiently. These cytokeratins are constitutively expressed at low levels (Fuchs and Green, 1978Fuchs E. Green H. Changes in keratin gene expression during terminal differentiation of the keratinocyte.Cell. 1978; 19: 1033-1042Abstract Full Text PDF Scopus (780) Google Scholar;Tyner and Fuchs, 1986Tyner A.L. Fuchs E. Evidence for posttranscriptional regulation of the keratins expressed during hyperproliferation and malignant transformation in human epidermis.J Cell Biol. 1986; 103: 1945-1955Crossref PubMed Scopus (122) Google Scholar). An increasing number of investigations have shown local cytotoxic effects of NO when generated at higher concentrations via the activation of the inducible NOS (Butler and Williams, 1993Butler A.R. Williams D.L.H. The physiological role of nitric oxide.Chem Soc Rev. 1993; 22: 233-241Crossref Google Scholar;Förstermann et al., 1994Förstermann U. Closs E.J. Pollock J.S. Nakane M. Schwarz P. Gath J. Kleinert H. Nitric oxide synthase isoenzymes. Characterization, purification, molecular cloning, and functions.Hypertension. 1994; 23: 1121-1131Crossref PubMed Scopus (960) Google Scholar), and it has been convincingly demonstrated that NO causes local organ destruction in autoimmune diseases (Kolb and Kolb-bachofen, 1992Kolb H. Kolb-bachofen V. Nitric oxide: A pathogenetic factor in autoimmunity.Immunol Today. 1992; 13: 157-160Abstract Full Text PDF PubMed Scopus (335) Google Scholar). The use of chemical NO donors is ideally suited to addressing the question of NO-mediated effects on skin cells. Chemistry has provided several molecules that generate NO after intracellular enzymatic degradation or spontaneous release in aqueous solutions with varying kinetics of decay (Kröncke et al., 1993Kröncke K.D. Brener H.H. Rodriguez M.L. Etzkorn K. Noack E.A. Kolb H. Kolb-bachofen V. Pancreatic islet cells are highly susceptible towards the cytotoxic effects of chemically generated nitric oxide.Biochem Biophys Acta. 1993; 1182: 221-229Crossref PubMed Scopus (102) Google Scholar). The use of these agents thus allows the activities of NOS enzymes to be experimentally mimicked and the effects of intracellular or extracellular NO generation in vitro to be studied. We have used this experimental tool to examine the effect of NO on keratinocyte viability, proliferation, and differentiation and compared these with dermal fibroblasts treated identically. Primary cultures of human keratinocytes and fibroblasts were derived from breast reduction material and also from foreskin material. Cells were grown in 100 mm cell culture dishes (Greiner, Frickenhausen, Germany) under standard culture conditions. Keratinocytes were maintained in serum-free keratinocyte medium (Gibco Life Technologies, Eggenstein, Germany) supplemented with penicillin-streptomycin (4 ml per 500 ml). Primary human fibroblasts were cultured in RPMI 1640 (PAA Laboratories, Linz, Austria) supplemented with 10% fetal calf serum otherwise under the same conditions. Cells were passaged every 4–5 d. Experiments were performed on eight-chamber or 16-chamber glass slides (Nunc LabTec, Wiesbaden, Germany) in the presence or absence of the NO donors nitroprusside (NP), heterocyclic sydnonimine derivative (SIN-1), S-nitrosothiol-N-acetyl-penicillamine (SNAP), or a polyamine/NO-complex [DETA/NO: 1-Hydroxy-2-oxo-3,3-bis (3-aminoethyl)-1-triazene]. NO donor concentrations ranged from 0.01 mM to 5 mM. At various time periods medium was removed and slides were dried and processed for in situ nick-translation or immunostaining procedure. Using 24 h, 2 × 24 h, 4 × 12 h, or 3 × 24 h incubation periods, medium was removed after 24 h or after 12 h and fresh medium with or without NO donor was added. Trypan blue dye exclusion was assessed and quantitated after a 5 min incubation and the number of cells excluding the dye was expressed as a percentage counted from several randomly chosen areas of each well. For detection of DNA strand breaks cells were fixed in acetone for 10 min. Endogenous peroxidase activity was blocked by incubating slides in methanol plus 0.3% hydrogen peroxide for 30 min. The in situ nick-translation mixture contained 3 μM biotin-dUTP, 5 U DNA polymerase I per 100 μl, 3 μM of each dGTP, dATP, dCTP, 50 mM Tris-HCL, pH 7.5, 5 mM MgCl2, and 0.1 mM dithiothreitol. The reaction was performed at room temperature for 20 min. The slides were then washed in phosphate buffered saline and processed for immunocytochemical detection of biotin-labeled UTP by peroxidase-labeled avidin, followed by the enzyme reaction using diaminobenzidine as substrate. Neutral red solution in phosphate buffered saline (Sigma, Deisenhofen, Germany) was added to each well to give a final concentration of 0.03% and incubated for 90 min at 37°C in the dark. Medium was removed, and cells were washed two times with phosphate buffered saline and dried. After dissolving in 100 μl isopropanol plus 1% 1 M HCl, the absorption of the probes was measured at 530 nm in an enzyme linked immunosorbent assay microplate reader (Multiskan Plus MK 2, Helsinki, Finland). Cells were stained with either the anti-Ki67 monoclonal antibody (Gerdes et al., 1984Gerdes J. Lemke H. Baisch H. Wacker H.H. Schwab U. Stein H. Cell cycle analysis of a cell proliferation associated human nuclear antigen defined by the monoclonal antibody Ki67.J Immunol. 1984; 133: 170-1715Google Scholar) from DAKO (Glostrup, Denmark) or the anti-cytokeratin 6 monoclonal antibody (Demirkesen et al., 1995Demirkesen C. Hoede N. Moll R. Epithelial markers and differentiation in adnexial neoplasms of the skin: An immunohistochemical study including individual cytokeratins.J Cutan Pathol. 1995; 22: 518-535Crossref PubMed Scopus (95) Google Scholar) from Boehringer Ingelheim (Heidelberg, Germany). Labeling procedures were performed by using the DAKO LSAB Kit (Peroxidase) following the manufacturer’s instructions. As negative controls, we used isotype-matched irrelevant monoclonal antibodies. After fixation with acetone at room temperature for 10 min, slides were covered either with the primary antibody (Ki67, cytokeratin 6) or with the control antibody for 30 min at room temperature. Cells were then incubated with a link-antibody and streptavidin peroxidase for 30 min each at room temperature, and substrate-chromogen-solution using diaminobenzidine as substrate was applied for 5 min at room temperature. Finally, slides were counterstained with hematoxylin and eosin. Nitroprusside was purchased from Merck (Darmstadt, Germany), SIN-1 was a gift from Cassella-Hoechst (Frankfurt am Main, Germany), DETA/NO was kindly provided by Olaf Grapenthin (Institute of Pharmaceutial Chemistry, Heinrich-Heine-University, Duesseldorf, Germany), and SNAP was synthesized and characterized as described previously (Fehsel et al., 1996Fehsel K. Kröncke K.D. Kolb-bachofen V. Assays for the detection of nitric oxide-induced apoptosis.Meth Enzymol. 1996; 269: 427-434bGoogle Scholar) and used at the concentrations indicated. Stock solutions were always freshly prepared and immediately used. Controls consisted of DETA/NO-NO and SNAP-NO at the highest relevant concentrations. These were obtained by prolonged incubation at 37°C of DETA/NO or SNAP yielding totally denitrosylated substances plus reaction end products. Statistical comparisons were performed with the paired t Student’s test. Significance refers to p < 0.05 or p < 0.001. NO at higher concentrations that are generated by the inducible NOS is generally assumed to have cytotoxic or cytostatic effects (Kröncke et al., 1994Kröncke K.D. Fehsel K. Alsdorff K. Kolb-bachofen V. Expression of inducible NO synthase in human monocytes.Immunobiol. 1994; 191: 267-268Google Scholar). As the relative sensitivity of human skin cells towards NO is not known, we initially analyzed whether NO induces cell death in primary cultures of human keratinocytes or fibroblasts. We used trypan blue exclusion to search for necrosis and in situ nick-translation to detect DNA strand breaks as a hallmark for apoptosis. Both keratinocytes and fibroblasts were incubated with the NO donors SIN-1 or SNAP, and keratinocytes were additionally treated with NP or DETA/NO at concentrations ranging from 0.5 mM to 5 mM for various periods of time. With both cell types, neither DNA strand breaks nor cellular lysis were significant at NO donor concentrations up to 5 mM. Only incubation with SIN-1, which simultaneously generates oxigen radicals, led to significant cell death (35.6% dead keratinocytes and 20.4% dead fibroblasts at 5.0 mM and 24 h) (Figure 1) and DNA damage (53.9% and 32.2% strand breaks in keratinocytes and fibroblasts at 5.0 mM and 24 h) (Figure 2a,b). A low, but significant cell death was found (25–30% of cultured keratinocytes or fibroblasts; data not shown) only at the highest and nonphysiologic concentrations of the different NO donors NP, DETA/NO, or SNAP (5.0 mM) and with a prolonged incubation period (48 h). These results suggest that both keratinocytes and fibroblasts express a relative resistance toward the cytotoxic effects of NO.Figure 2Even at nonphysiologic concentrations NO does not significantly induce apoptosis in keratinocytes and fibroblasts. Strand breaks induced by NP, SIN-1, SNAP, or DETA/NO in primary human keratinocytes (a) or fibroblasts (b) after a 24 h incubation period were visualized by in situ nick-translation. Each bar represents the mean ± SD of four independent experiments. Significance of differences in NO-mediated apoptosis was determined by comparing 1 mM with untreated controls or 5 mM with 1 mM (*p < 0.05, **p < 0.001).View Large Image Figure ViewerDownload (PPT) Primary human keratinocytes or fibroblasts were incubated with various concentrations of DETA/NO that, due to its half-time (t1/2 = 7 h), allows for studying effects of long-term NO exposure. Cells were cultured for a total of 48 h with addition of the NO donor every 24 h or every 12 h. Keratinocytes maintained at concentrations of 0.01 mM to 0.25 mM of DETA/NO, exhibited increased positive immunostaining for Ki67 as an indication for increasing proliferation (Figure 3a). The same effect was found with SNAP, albeit at higher concentrations (Figure 3b), in accordance with the fact that DETA/NO releases 2 mol of NO per mol of polyamine complex, whereas SNAP releases NO in a 1:1 ratio. With higher NO donor concentrations the reverse effect was found, i.e., Ki67 labeling decreased as an indication for an anti-proliferative activity. By measuring cell numbers via neutral red staining we could confirm this biphasic effect on cell proliferation (Figure 4). These effects were found with three different donors of cells and two different skin regions that cells were derived from. Interestingly, with dermal fibroblasts cultured under the identical conditions we found a different type of response: here, a proliferation enhancing effect could not be demonstrated. Even at the lowest concentrations a significant decrease of Ki67 expression and proliferation was found with both methods (Figure 3a,b, Figure 4). Figure 5 shows the Ki67 expression in both keratinocytes and fibroblasts depending on the different concentrations of DETA/NO. We further investigated the effects of exogenous NO on keratinocyte differentiation by studying the expression of cytokeratin 6. By immunocytochemistry, we determined the percentage of cells with weak or strong staining as an indicator for ongoing differentiation. Cells were incubated with DETA/NO for 2 × 24 h as described before. In primary keratinocytes exposed to low NO donor concentrations up to 0.05 mM DETA/NO, a slight but not significant increase of cells staining weakly for anti-cytokeratin 6 was observed in all experiments. At concentrations ranging from 0.05 mM up to 1.0 mM DETA/NO, the expression pattern changed drastically with the majority of cells exhibiting strong staining as an indication for ongoing differentiation of keratinocytes (Figure 6a,b, Figure 7). The results found with DETA/NO as NO donor could again be reproduced with SNAP at incubation periods of 2 × 24 h (Figure 8a) or 4 × 12 h (data not shown). We also analyzed whether the use of DETA/NO for longer periods of time would alter the differentiation pattern, but findings were essentially the same (Figure 8b). There is a multitude of effects and functions for NO described so far, one of which is cytotoxicity leading to the destruction of bacteria and parasites but also of cells and tissues, thereby contributing to unspecific immunity and inflammation (Corbett et al., 1996Corbett J.A. Kwon G. Marino M.H. Rodi C.P. Sullivan P.M. Turk J. McDaniel M.L. Tyrosine kinase inhibition prevent cytokine-induced expression of iNOS and COX-2 by human islets.Am J Physiol. 1996; 270: 1581-1587PubMed Google Scholar;Brenner et al., 1997Brenner T. Brockl S. Szafer F. Sobel L. Parkinson J.F. Perez D.H. Steinman L. Inhibition of nitric oxide synthase for treatment of experimental autoimmune encephalomyelitis.J Immunol. 1997; 158: 2940-2946PubMed Google Scholar). Moreover, several reports have demonstrated the potential of NO to influence the proliferation and differentiation cascade in several mammalian cells (Nüssler and Billiar, 1993Nüssler A.K. Billiar T.R. Inflammation, immunoregulation, and inducible nitric oxide synthase.J Leukocyte Biol. 1993; 54: 171-178Crossref PubMed Scopus (809) Google Scholar;Saunders and Jetten, 1994Saunders N.A. Jetten A.M. Control of growth regulatory and differentiation-specific genes in human epidermal keratinocytes by interferon γ: Antagonism by retinoic acid and transforming growth factor β1.J Biol Chem. 1994; 269: 2016-2022Abstract Full Text PDF PubMed Google Scholar;Arany et al., 1996Arany J. Brysk M.M. Brysk H. Tyring S.K. Regulation of inducible nitric oxide synthase mRNA levels by differentiation and cytokines in human keratinocytes.Biophys Res Commun. 1996; 220: 618-622Crossref PubMed Scopus (69) Google Scholar). Because the relative sensitivity of human skin cells towards NO is not yet known, we investigated whether NO mediates cytotoxicity or influences proliferation and differentiation in cultures of primary human keratinocytes and fibroblasts. In a first set of experiments, we analyzed whether NO induces cell death in these cell cultures. In human skin, physiologic cell death can result from apoptosis (Albina et al., 1993Albina J.E. Cui S. Mateo R.B. Reichner J.S. Nitric oxide-mediated apoptosis in murine peritoneal macrophages.J Immunol. 1993; 150: 5080-5085PubMed Google Scholar;Kaneo et al., 1995Kaneo H. Fugii J. Seo H.G. et al.Apoptotic cell death triggered by nitric oxide in pancreatic beta-cells.Diabetes. 1995; 44: 733-738Crossref Google Scholar), but the exact mechanism of cell death may vary from one type of cell to another. Moreover, morphologic evidence exists that apoptosis also contributes to the pathogenesis of several human skin diseases, although knowledge about potential inducers of apoptosis and about molecular and structural alterations in human skin is scarce (Paus et al., 1993Paus R. Rosenbach T. Haas N. Czarnetzki B.M. Patterns of cell death: the significance of apoptosis for dermatology.Exp Dermatol. 1993; 2: 3-11Crossref PubMed Scopus (77) Google Scholar). One result of our investigations was that epidermal human keratinocytes and fibroblasts are resistant towards cytotoxic or apoptosis-inducing effects of exogenous NO. Of all NO donors used, only SIN-1 resulted in significant cell death at physiologically relevant concentrations. It is likely that this is due to oxigen free radicals produced simultaneously with NO during the decay of SIN-1 but not with any of the other NO donors used here. These findings suggest that NO generation in human skin diseases is not directly associated with local cell destruction, in contrast to findings in several other human diseases. When studying the effect of NO on skin cell growth, however, we found a unique and apparently cell type-specific regulatory activity: keratinocytes show an increasing proliferation and a decreasing differentiation when maintained at low NO concentrations, whereas the pattern of proliferation and differentiation changes into the opposite pattern when cultured at higher concentrations. This biphasic activity of NO on the proliferation and the differentiation cascade is readily seen, although keratinocytes are maintained under proliferative culture conditions as is reflected by the relatively high expression of Ki67 in the absence of NO donors. Interestingly, skin fibroblasts did not reveal this biphasic type of response, but exhibited a significant growth arrest even at the lowest concentrations of NO donors used. For these experiments cells were exposed to repetitive doses of the polyamine/NO-complex DETA/NO that decays in a first order kinetic. Accordingly, 2 mM of DETA/NO will generate 6.6 μM of NO per minute (Berendji et al., 1997Berendji D. Kolb-bachofen V. Meyer K.L. Grapenthin O. Weber H. Wahn V. Kröncke K.D. Nitric oxide mediates intracytoplasmatic and intranuclear zinc release.FEBS Lett. 1997; 405: 37-41Abstract Full Text Full Text PDF PubMed Scopus (146) Google Scholar). In the immediate vicinity of a cell monolayer that enzymatically generates NO, a steady-state concentration of about 4–5 μM of NO has been recently calculated (Laurent et al., 1996Laurent M. Lepoivre M. Tenu J.P. Kinetic modelling of the nitric oxide gradient generated in vitro by adherent cells expressing inducible nitric oxide synthase.Biochem J. 1996; 314: 109-113Crossref PubMed Scopus (85) Google Scholar). Therefore, DETA/NO concentrations of up to 2 mM as used here can be considered as near physiologic and comparable NO releases are indeed seen with live cells. Both cell growth and differentiation regulating activities of NO have been described previously. In primary human keratinocytes it was found that endogenous NO synthesis correlates with onset of differentiation (Arany et al., 1996Arany J. Brysk M.M. Brysk H. Tyring S.K. Regulation of inducible nitric oxide synthase mRNA levels by differentiation and cytokines in human keratinocytes.Biophys Res Commun. 1996; 220: 618-622Crossref PubMed Scopus (69) Google Scholar). Two other studies examined the effects of NO donors or iNOS-generated NO in fibroblasts (Du et al., 1997Du M. Islam M. Ohmura Y. Moriyama Y. Fujimura S. Promotion of proliferation of murine BALB/c3T3 fibroblasts mediated by nitric oxide at lower concentrations.Biochem Mol Biol Int. 1997; 41: 625-631PubMed Google Scholar;Gansauge et al., 1997Gansauge S. Gansauge F. Nüssler A.K. Rau B. Poch B. Schoenberg M.H. Beger H.G. Exogenous, but not endogenous, nitric oxide increases proliferation rates in senescent human fibroblasts.FEBS Lett. 1997; 410: 160-164Abstract Full Text Full Text PDF PubMed Scopus (43) Google Scholar), both describing an increased cell proliferation with single doses of NP or SNAP or GSNO. Results are not comparable, mostly because we studied effects of long-term exposure with repeated addition of the NO donors DETA/NO or SNAP. After a 24 h incubation period of fibroblasts with single doses of NO donors like SNAP (t1/2≈ 4 h) or GSNO (t1/2≈ 70 min), some of the measured effects may reflect cellular responses after a release from NO-mediated blockade, whereas blocking is maintained with constant NO release from iNOS or from repetitive doses of DETA/NO (t1/2≈ 7 h). In addition, the use of NP argues against a difference between NO generated exogenously versus NO produced within cells, as this agent will generate NO only after enzymatic breakdown within cells (for a review seeKröncke et al., 1995bKröncke K.D. Fehsel K. Kolb-bachofen V. Inducible nitric oxide synthase and its product nitric oxide, a small molecule with complex biological activities.Biol Chem Hoppe-Seyler. 1995 b; 376: 327-343Crossref PubMed Google Scholar). In summary, our results demonstrate an important role for NO in human skin homeostasis, exerting both increased proliferation as well as the onset of differentiation, depending on local NO concentrations and cell type. We thank Marija Lovrencic, Ulla Lammersen, and Christa-Maria Wilkens for technical assistance, and Martha Turken for photographic assistance. This work was supported by a study grant (to Schu 1164/1–1) and a research grant (to V.K.-B., Sonderforschungsbereich 503), both from the Deutsche Forschungsgemeinschaft." @default.
• W2039786301 created "2016-06-24" @default.
• W2039786301 creator A5016188699 @default.
• W2039786301 creator A5030754917 @default.
• W2039786301 creator A5037531417 @default.
• W2039786301 creator A5040011400 @default.
• W2039786301 creator A5078443816 @default.
• W2039786301 creator A5045984981 @default.
• W2039786301 date "1998-08-01" @default.
• W2039786301 modified "2023-10-09" @default.
• W2039786301 title "Biphasic Effect of Exogenous Nitric Oxide on Proliferation and Differentiation in Skin Derived Keratinocytes but Not Fibroblasts" @default.
• W2039786301 cites W1491342058 @default.
• W2039786301 cites W1539812004 @default.
• W2039786301 cites W1964813912 @default.
• W2039786301 cites W1973869185 @default.
• W2039786301 cites W2017419704 @default.
• W2039786301 cites W2028764382 @default.
• W2039786301 cites W2029903567 @default.
• W2039786301 cites W2030172601 @default.
• W2039786301 cites W2062300120 @default.
• W2039786301 cites W2068932601 @default.
• W2039786301 cites W2069810321 @default.
• W2039786301 cites W2072849495 @default.
• W2039786301 cites W2087435915 @default.
• W2039786301 cites W2114365237 @default.
• W2039786301 cites W2126486896 @default.
• W2039786301 cites W2127241809 @default.
• W2039786301 cites W2137838799 @default.
• W2039786301 cites W2163275136 @default.
• W2039786301 cites W2165586610 @default.
• W2039786301 cites W2216604643 @default.
• W2039786301 cites W2333302658 @default.
• W2039786301 cites W2417634332 @default.
• W2039786301 cites W4313323083 @default.
• W2039786301 doi "https://doi.org/10.1046/j.1523-1747.1998.00268.x" @default.
• W2039786301 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/9699731" @default.
• W2039786301 hasPublicationYear "1998" @default.
• W2039786301 type Work @default.
• W2039786301 sameAs 2039786301 @default.
• W2039786301 citedByCount "186" @default.
• W2039786301 countsByYear W20397863012012 @default.
• W2039786301 countsByYear W20397863012013 @default.
• W2039786301 countsByYear W20397863012014 @default.
• W2039786301 countsByYear W20397863012015 @default.
• W2039786301 countsByYear W20397863012016 @default.
• W2039786301 countsByYear W20397863012017 @default.
• W2039786301 countsByYear W20397863012018 @default.
• W2039786301 countsByYear W20397863012019 @default.
• W2039786301 countsByYear W20397863012020 @default.
• W2039786301 countsByYear W20397863012021 @default.
• W2039786301 countsByYear W20397863012022 @default.
• W2039786301 countsByYear W20397863012023 @default.
• W2039786301 crossrefType "journal-article" @default.
• W2039786301 hasAuthorship W2039786301A5016188699 @default.
• W2039786301 hasAuthorship W2039786301A5030754917 @default.
• W2039786301 hasAuthorship W2039786301A5037531417 @default.
• W2039786301 hasAuthorship W2039786301A5040011400 @default.
• W2039786301 hasAuthorship W2039786301A5045984981 @default.
• W2039786301 hasAuthorship W2039786301A5078443816 @default.
• W2039786301 hasBestOaLocation W20397863011 @default.
• W2039786301 hasConcept C178790620 @default.
• W2039786301 hasConcept C185592680 @default.
• W2039786301 hasConcept C202751555 @default.
• W2039786301 hasConcept C2777074287 @default.
• W2039786301 hasConcept C519581460 @default.
• W2039786301 hasConcept C55493867 @default.
• W2039786301 hasConcept C86803240 @default.
• W2039786301 hasConcept C95444343 @default.
• W2039786301 hasConceptScore W2039786301C178790620 @default.
• W2039786301 hasConceptScore W2039786301C185592680 @default.
• W2039786301 hasConceptScore W2039786301C202751555 @default.
• W2039786301 hasConceptScore W2039786301C2777074287 @default.
• W2039786301 hasConceptScore W2039786301C519581460 @default.
• W2039786301 hasConceptScore W2039786301C55493867 @default.
• W2039786301 hasConceptScore W2039786301C86803240 @default.
• W2039786301 hasConceptScore W2039786301C95444343 @default.
• W2039786301 hasIssue "2" @default.
• W2039786301 hasLocation W20397863011 @default.
• W2039786301 hasLocation W20397863012 @default.
• W2039786301 hasOpenAccess W2039786301 @default.
• W2039786301 hasPrimaryLocation W20397863011 @default.
• W2039786301 hasRelatedWork W1531601525 @default.
• W2039786301 hasRelatedWork W2319480705 @default.
• W2039786301 hasRelatedWork W2384464875 @default.
• W2039786301 hasRelatedWork W2398689458 @default.
• W2039786301 hasRelatedWork W2606230654 @default.
• W2039786301 hasRelatedWork W2607424097 @default.
• W2039786301 hasRelatedWork W2748952813 @default.
• W2039786301 hasRelatedWork W2899084033 @default.
• W2039786301 hasRelatedWork W2948807893 @default.
• W2039786301 hasRelatedWork W2778153218 @default.
• W2039786301 hasVolume "111" @default.
• W2039786301 isParatext "false" @default.
• W2039786301 isRetracted "false" @default.
• W2039786301 magId "2039786301" @default.
• W2039786301 workType "article" @default.